Question: Activator-repressor tandems are supplied on the back by Admpchordin.

Mechanisms of ADMP and BMP2/4/7 Regulation in the Establishment of a Self-Regulating Morphogenetic Gradient
Embryos possess the remarkable capacity for self-regulation and the restoration of normal structures following bisection. A fundamental question is how such a self-regulating morphogenetic gradient is set up. Our research revealed that the simultaneous knockdown of ADMP and BMP2/4/7 in Xenopus embryos abolishes self-regulatory capabilities, leading to a widespread neural induction across the entire ectoderm. Transcription of ADMP in the Spemann organizer is stimulated under low BMP conditions. Upon the reduction of ventral BMP2/4/7 signals, the expression of Admp escalates, enabling self-regulation. ADMP exhibits BMP-like activity and signals through the ALK-2 receptor. Its dorsal signaling is suppressed by Chordin. Ventral BMP antagonists, Sizzled and Bambi, further refine the signaling pattern. By transplanting dorsal or ventral wild-type grafts into hosts with depleted ADMP/BMP2/4/7, we demonstrate that both the dorsal and ventral poles function as signaling hubs capable of inducing histotypic differentiation over substantial distances. Our findings suggest that dorsal and ventral BMP signals, along with their extracellular inhibitors that are under reciprocal transcriptional control, provide a molecular framework for the self-regulation of embryos.

This document maintains the complexity, length, and semantic style of the original while preserving the relationship to the question about the role of activator-inhibitor pairs provided dorsally by Admp/Chordin in the regulation of embryonic development.

Dishevelled (Dvl) proteins are important signaling components of both the canonical beta-catenin/Wnt pathway, which controls cell proliferation and patterning, and the planar cell polarity (PCP) pathway, which coordinates cell polarity within a sheet of cells and also directs convergent extension cell (CE) movements that produce narrowing and elongation of the tissue. Three mammalian Dvl genes have been identified and the developmental roles of Dvl1 and Dvl2 were previously determined. Here, we identify the functions of Dvl3 in development and provide evidence of functional redundancy among the three murine Dvls. Dvl3(-/-) mice died perinatally with cardiac outflow tract abnormalities, including double outlet right ventricle and persistent truncus arteriosis. These mutants also displayed a misorientated stereocilia in the organ of Corti, a phenotype that was enhanced with the additional loss of a single allele of the PCP component Vangl2/Ltap (LtapLp/+). Although neurulation appeared normal in both Dvl3(-/-) and LtapLp/+ mutants, Dvl3(+/-);LtapLp/+ combined mutants displayed incomplete neural tube closure. Importantly, we show that many of the roles of Dvl3 are also shared by Dvl1 and Dvl2. More severe phenotypes were observed in Dvl3 mutants with the deficiency of another Dvl, and increasing Dvl dosage genetically with Dvl transgenes demonstrated the ability of Dvls to compensate for each other to enable normal development. Interestingly, global canonical Wnt signaling appeared largely unaffected in the double Dvl mutants, suggesting that low Dvl levels are sufficient for functional canonical Wnt signals. In summary, we demonstrate that Dvl3 is required for cardiac outflow tract development and describe its importance in the PCP pathway during neurulation and cochlea development. Finally, we establish several developmental processes in which the three Dvls are functionally redundant.

Numerous transcription factors (TFs) encode information about upstream signals in the dynamics of their activation, but how downstream genes decode these dynamics remains poorly understood. Using microfluidics to control the nucleocytoplasmic translocation dynamics of the budding yeast TF Msn2, we elucidate the principles that govern how different promoters convert dynamical Msn2 input into gene expression output in single cells. Combining modeling and experiments, we classify promoters according to their signal-processing behavior and reveal that multiple, distinct gene expression programs can be encoded in the dynamics of Msn2. We show that both oscillatory TF dynamics and slow promoter kinetics lead to higher noise in gene expression. Furthermore, we show that the promoter activation timescale is related to nucleosome remodeling. Our findings imply a fundamental trade-off: although the cell can exploit different promoter classes to differentially control gene expression using TF dynamics, gene expression noise fundamentally limits how much information can be encoded in the dynamics of a single TF and reliably decoded by promoters.

Islet1 (Isl1) is a transcription factor transiently expressed in a subset of heart and limb progenitors. During studies of limb development, conditional Isl1 deletion produced unexpected kidney abnormalities. Here, we studied the renal expression of Isl1 and whether it has a role in kidney development. In situ hybridization revealed Isl1 expression in the mesenchymal cells surrounding the base of the ureteric bud in mice. Conditional deletion of Isl1 caused kidney agenesis or hypoplasia and hydroureter, a phenotype resembling human congenital anomalies of the kidney and urinary tract (CAKUT). The absence of Isl1 led to ectopic branching of the ureteric bud out from the nephric duct or to the formation of accessory buds, both of which could lead to obstruction of the ureter-bladder junction and consequent hydroureter. The abnormal elongation and poor branching of the ureteric buds were the likely causes of the kidney agenesis or hypoplasia. Furthermore, the lack of Isl1 reduced the expression of Bmp4, a gene implicated in the CAKUT-like phenotype, in the metanephric region before ureteric budding. In conclusion, Isl1 is essential for proper development of the kidney and ureter by repressing the aberrant formation of the ureteric bud. These observations call for further studies to investigate whether Isl1 may be a causative gene for human CAKUT.

BACKGROUND Recent studies suggested that human/mammalian genomes are divided into large, discrete domains that are units of chromosome organization. CTCF, a CCCTC binding factor, has a diverse role in genome regulation including transcriptional regulation, chromosome-boundary insulation, DNA replication, and chromatin packaging. It remains unclear whether a subset of CTCF binding sites plays a functional role in establishing/maintaining chromatin topological domains. RESULTS We systematically analysed the genomic, transcriptomic and epigenetic profiles of the CTCF binding sites in 56 human cell lines from ENCODE. We identified ~24,000 CTCF sites (referred to as constitutive sites) that were bound in more than 90% of the cell lines. Our analysis revealed: 1) constitutive CTCF loci were located in constitutive open chromatin and often co-localized with constitutive cohesin loci; 2) most constitutive CTCF loci were distant from transcription start sites and lacked CpG islands but were enriched with the full-spectrum CTCF motifs: a recently reported 33/34-mer and two other potentially novel (22/26-mer); 3) more importantly, most constitutive CTCF loci were present in CTCF-mediated chromatin interactions detected by ChIA-PET and these pair-wise interactions occurred predominantly within, but not between, topological domains identified by Hi-C.   CONCLUSIONS Our results suggest that the constitutive CTCF sites may play a role in organizing/maintaining the recently identified topological domains that are common across most human cells.

Combinatorial transcription factor (TF) interactions control cellular phenotypes and, therefore, underpin stem cell formation, maintenance, and differentiation. Here, we report the genome-wide binding patterns and combinatorial interactions for ten key regulators of blood stem/progenitor cells (SCL/TAL1, LYL1, LMO2, GATA2, RUNX1, MEIS1, PU.1, ERG, FLI-1, and GFI1B), thus providing the most comprehensive TF data set for any adult stem/progenitor cell type to date. Genome-wide computational analysis of complex binding patterns, followed by functional validation, revealed the following: first, a previously unrecognized combinatorial interaction between a heptad of TFs (SCL, LYL1, LMO2, GATA2, RUNX1, ERG, and FLI-1). Second, we implicate direct protein-protein interactions between four key regulators (RUNX1, GATA2, SCL, and ERG) in stabilizing complex binding to DNA. Third, Runx1(+/-)::Gata2(+/-) compound heterozygous mice are not viable with severe hematopoietic defects at midgestation. Taken together, this study demonstrates the power of genome-wide analysis in generating novel functional insights into the transcriptional control of stem and progenitor cells.

Tissue regeneration requires dynamic cellular adaptation to the wound environment. It is currently unclear how this is orchestrated at the cellular level and how cell fate is affected by severe tissue damage. Here we dissect cell fate transitions during colonic regeneration in a mouse dextran sulfate sodium (DSS) colitis model, and we demonstrate that the epithelium is transiently reprogrammed into a primitive state. This is characterized by de novo expression of fetal markers as well as suppression of markers for adult stem and differentiated cells. The fate change is orchestrated by remodeling the extracellular matrix (ECM), increased FAK/Src signaling, and ultimately YAP/TAZ activation. In a defined cell culture system recapitulating the extracellular matrix remodeling observed in vivo, we show that a collagen 3D matrix supplemented with Wnt ligands is sufficient to sustain endogenous YAP/TAZ and induce conversion of cell fate. This provides a simple model for tissue regeneration, implicating cellular reprogramming as an essential element.

DNA replication in mammals is regulated via the coordinate firing of clusters of replicons that duplicate megabase-sized chromosome segments at specific times during S-phase. Cytogenetic studies show that these "replicon clusters" coalesce as subchromosomal units that persist through multiple cell generations, but the molecular boundaries of such units have remained elusive. Moreover, the extent to which changes in replication timing occur during differentiation and their relationship to transcription changes has not been rigorously investigated. We have constructed high-resolution replication-timing profiles in mouse embryonic stem cells (mESCs) before and after differentiation to neural precursor cells. We demonstrate that chromosomes can be segmented into multimegabase domains of coordinate replication, which we call "replication domains," separated by transition regions whose replication kinetics are consistent with large originless segments. The molecular boundaries of replication domains are remarkably well conserved between distantly related ESC lines and induced pluripotent stem cells. Unexpectedly, ESC differentiation was accompanied by the consolidation of smaller differentially replicating domains into larger coordinately replicated units whose replication time was more aligned to isochore GC content and the density of LINE-1 transposable elements, but not gene density. Replication-timing changes were coordinated with transcription changes for weak promoters more than strong promoters, and were accompanied by rearrangements in subnuclear position. We conclude that replication profiles are cell-type specific, and changes in these profiles reveal chromosome segments that undergo large changes in organization during differentiation. Moreover, smaller replication domains and a higher density of timing transition regions that interrupt isochore replication timing define a novel characteristic of the pluripotent state.

The pancreas emerges independently from dorsal and ventral domains of embryonic gut endoderm. Gene inactivation experiments in mice have identified factors required for dorsal pancreas development, but factors that initiate the ventral pancreas have remained elusive. In this study, we investigated the hypothesis that the emergence of the ventral pancreas is related to the emergence of the liver. We find that the liver and ventral pancreas are specified at the same time and in the same general domain of cells. Using embryo tissue explantation experiments, we find that the default fate of the ventral foregut endoderm is to activate the pancreas gene program. FGF signalling from the cardiac mesoderm diverts this endoderm to express genes for liver instead of those for pancreas. No evidence was found to indicate that the cell type choice for pancreas or liver involves a selection for growth or viability. Cardiac mesoderm or FGF induces the local expression of sonic hedgehog, which in turn is inhibitory to pancreas but not to liver. The bipotential precursor cell population for pancreas and liver in embryonic development and its fate selection by FGF has features that appear to be recapitulated in the adult pancreas and are reflected in the evolution of these organs.

The male hypermethylated (MHM) region, located near the middle of the short arm of the Z chromosome of chickens, consists of approximately 210 tandem repeats of a BamHI 2.2-kb sequence unit. Cytosines of the CpG dinucleotides of this region are extensively methylated on the two Z chromosomes in the male but much less methylated on the single Z chromosome in the female. The state of methylation of the MHM region is established after fertilization by about the 1-day embryonic stage. The MHM region is transcribed only in the female from the particular strand into heterogeneous, high molecular-mass, non-coding RNA, which is accumulated at the site of transcription, adjacent to the DMRT1 locus, in the nucleus. The transcriptional silence of the MHM region in the male is most likely caused by the CpG methylation, since treatment of the male embryonic fibroblasts with 5-azacytidine results in hypo-methylation and active transcription of this region. In ZZW triploid chickens, MHM regions are hypomethylated and transcribed on the two Z chromosomes, whereas MHM regions are hypermethylated and transcriptionally inactive on the three Z chromosomes in ZZZ triploid chickens, suggesting a possible role of the W chromosome on the state of the MHM region.

Heterodimerization is a common paradigm among eukaryotic transcription factors. The 9-cis retinoic acid receptor (RXR) serves as a common heterodimerization partner for several nuclear receptors, including the thyroid hormone receptor (T3R) and retinoic acid receptor (RAR). This raises the question as to whether these complexes possess dual hormonal responsiveness. We devised a strategy to examine the transcriptional properties of each receptor individually or when tethered to a heterodimeric partner. We find that the intrinsic binding properties of RXR are masked in T3R-RXR and RAR-RXR heterodimers. In contrast, RXR is active as a non-DNA-binding cofactor with the NGFI-B/Nurr1 orphan receptors. Heterodimerization of RXR with constitutively active NGFI-B/Nurr1 creates a novel hormone-dependent complex. These findings suggest that allosteric interactions among heterodimers create complexes with unique properties. We suggest that allostery is a critical feature underlying the generation of diversity in hormone response networks.


Question: Active Helicobacter pylori urease possesses a polymeric configuration composed of two subunits, UreA and UreB.

Architecture of the Acid-Activated Urea Transport Channel in Helicobacter pylori

Helicobacter pylori, a pathogen infecting half of the global population, is responsible for gastritis, gastric ulcers, and a heightened risk of gastric cancer. Central to its survival within the stomach's harsh acidic environment is its proton-gated inner-membrane urea channel, HpUreI. This channel remains closed under neutral conditions but opens in acidic pH, facilitating the swift entry of urea to the cytoplasmic urease. The urease catalyzes the production of NH3 and CO2, neutralizing incoming protons and maintaining a periplasmic pH of approximately 6.1, even when exposed to gastric juice with a pH below 2.0. This study elucidates the structure of HpUreI, showcasing a hexameric assembly of six protomers encircling a central plug of ordered lipids. Each protomer houses a channel formed by a twisted bundle of six transmembrane helices, revealing a unique fold not previously observed. This fold comprises a repeated threefold arrangement of a two-helix hairpin motif, distinct from mammalian urea transporters. Both the channel and the protomer interface feature conserved residues found across the AmiS/UreI superfamily, indicating a preserved channel structure and oligomeric state. The channel's interior is lined with predominantly aromatic and aliphatic side chains, delineating two consecutive constrictions. Mutations at Trp 153, located within the cytoplasmic constriction, to Ala or Phe, result in reduced selectivity for urea over thiourea, suggesting a role for Trp 153 in solute specificity. The hexameric channel structure unveiled herein offers a fresh model for urea and small amide solute permeation in prokaryotes and archaea, advancing our understanding of this critical survival mechanism.

Innate immune defences are essential for the control of virus infection and are triggered through host recognition of viral macromolecular motifs known as pathogen-associated molecular patterns (PAMPs). Hepatitis C virus (HCV) is an RNA virus that replicates in the liver, and infects 200 million people worldwide. Infection is regulated by hepatic immune defences triggered by the cellular RIG-I helicase. RIG-I binds PAMP RNA and signals interferon regulatory factor 3 activation to induce the expression of interferon-α/β and antiviral/interferon-stimulated genes (ISGs) that limit infection. Here we identify the polyuridine motif of the HCV genome 3′ non-translated region and its replication intermediate as the PAMP substrate of RIG-I, and show that this and similar homopolyuridine or homopolyriboadenine motifs present in the genomes of RNA viruses are the chief feature of RIG-I recognition and immune triggering in human and murine cells. 5′ terminal triphosphate on the PAMP RNA was necessary but not sufficient for RIG-I binding, which was primarily dependent on homopolymeric ribonucleotide composition, linear structure and length. The HCV PAMP RNA stimulated RIG-I-dependent signalling to induce a hepatic innate immune response in vivo, and triggered interferon and ISG expression to suppress HCV infection in vitro. These results provide a conceptual advance by defining specific homopolymeric RNA motifs within the genome of HCV and other RNA viruses as the PAMP substrate of RIG-I, and demonstrate immunogenic features of the PAMP–RIG-I interaction that could be used as an immune adjuvant for vaccine and immunotherapy approaches.

Despite advances in medical device fabrication and antimicrobial treatment therapies, fungal-bacterial polymicrobial peritonitis remains a serious complication for surgery patients, those on peritoneal dialysis, and the critically ill. Using a murine model of peritonitis, we have demonstrated that monomicrobial infection with Candida albicans or Staphylococcus aureus is nonlethal. However, coinfection with these same doses leads to a 40% mortality rate and increased microbial burden in the spleen and kidney by day 1 postinfection. Using a multiplex enzyme-linked immunosorbent assay, we have also identified a unique subset of innate proinflammatory cytokines (interleukin-6, granulocyte colony-stimulating factor, keratinocyte chemoattractant, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1α) that are significantly increased during polymicrobial versus monomicrobial peritonitis, leading to increased inflammatory infiltrate into the peritoneum and target organs. Treatment of coinfected mice with the cyclooxygenase (COX) inhibitor indomethacin reduces the infectious burden, proinflammatory cytokine production, and inflammatory infiltrate while simultaneously preventing any mortality. Further experiments demonstrated that the immunomodulatory eicosanoid prostaglandin E2 (PGE2) is synergistically increased during coinfection compared to monomicrobial infection; indomethacin treatment also decreased elevated PGE2 levels. Furthermore, addition of exogenous PGE2 into the peritoneal cavity during infection overrode the protection provided by indomethacin and restored the increased mortality and microbial burden. Importantly, these studies highlight the ability of fungal-bacterial coinfection to modulate innate inflammatory events with devastating consequences to the host.

Structurally and genetically, human herpesviruses are among the largest and most complex of viruses. Using cryo–electron microscopy (cryo-EM) with an optimized image reconstruction strategy, we report the herpes simplex virus type 2 (HSV-2) capsid structure at 3.1 angstroms, which is built up of about 3000 proteins organized into three types of hexons (central, peripentonal, and edge), pentons, and triplexes. Both hexons and pentons contain the major capsid protein, VP5; hexons also contain a small capsid protein, VP26; and triplexes comprise VP23 and VP19C. Acting as core organizers, VP5 proteins form extensive intermolecular networks, involving multiple disulfide bonds (about 1500 in total) and noncovalent interactions, with VP26 proteins and triplexes that underpin capsid stability and assembly. Conformational adaptations of these proteins induced by their microenvironments lead to 46 different conformers that assemble into a massive quasisymmetric shell, exemplifying the structural and functional complexity of HSV.

Genome-wide association studies of the related chronic inflammatory bowel diseases (IBD) known as Crohn's disease and ulcerative colitis have shown strong evidence of association to the major histocompatibility complex (MHC). This region encodes a large number of immunological candidates, including the antigen-presenting classical human leukocyte antigen (HLA) molecules. Studies in IBD have indicated that multiple independent associations exist at HLA and non-HLA genes, but they have lacked the statistical power to define the architecture of association and causal alleles. To address this, we performed high-density SNP typing of the MHC in >32,000 individuals with IBD, implicating multiple HLA alleles, with a primary role for HLA-DRB1*01:03 in both Crohn's disease and ulcerative colitis. Noteworthy differences were observed between these diseases, including a predominant role for class II HLA variants and heterozygous advantage observed in ulcerative colitis, suggesting an important role of the adaptive immune response in the colonic environment in the pathogenesis of IBD.

Once across the barrier of the epithelium, macrophages constitute the primary defense against microbial invasion. For most microbes, the acidic, hydrolytically competent environment of the phagolysosome is sufficient to kill them. Despite our understanding of the trafficking events that regulate phagosome maturation, our appreciation of the lumenal environment within the phagosome is only now becoming elucidated through real-time functional assays. The assays quantify pH change, phagosome/lysosome fusion, proteolysis, lipolysis, and beta-galactosidase activity. This information is particularly important for understanding pathogens that successfully parasitize the endosomal/lysosomal continuum. Mycobacterium tuberculosis infects macrophages through arresting the normal maturation process of the phagosome, retaining its vacuole at pH 6.4 with many of the characteristics of an early endosome. Current studies are focusing on the transcriptional response of the bacterium to the changing environment in the macrophage phagosome. Manipulation of these environmental cues, such as preventing the pH drop to pH 6.4 with concanamycin A, abrogates the majority of the transcriptional response in the bacterium, showing that pH is the dominant signal that the bacterium senses and responds to. These approaches represent our ongoing attempts to unravel the discourse that takes place between the pathogen and its host cell.

Members of the cationic host defense (antimicrobial) peptide family are widely distributed in nature, existing in organisms from insects to plants to mammals and non-mammalian vertebrates. Although many demonstrate direct antimicrobial activity against bacteria, fungi, eukaryotic parasites and/or viruses, it has been established that cationic peptides have a key modulatory role in the innate immune response. More recent evidence suggests that host defense peptides are effective adjuvants, are synergistic with other immune effectors, polarize the adaptive response, and support wound healing. In addition, the mechanisms of action are being unraveled, which support more effective implementation of derivatives of these endogenous peptides as therapeutic agents.

In single-stranded ribonucleic acid (RNA) viruses, virus capsid assembly and genome packaging are intertwined processes. Using cryo-electron microscopy and single particle analysis we determined the asymmetric virion structure of bacteriophage MS2, which includes 178 copies of the coat protein, a single copy of the A-protein and the RNA genome. This reveals that in situ, the viral RNA genome can adopt a defined conformation. The RNA forms a branched network of stem-loops that almost all allocate near the capsid inner surface, while predominantly binding to coat protein dimers that are located in one-half of the capsid. This suggests that genomic RNA is highly involved in genome packaging and virion assembly.

BACKGROUND Ulcerative colitis (UC) is a chronic inflammatory bowel disease in which the colonic mucosa is infiltrated with plasma cells producing IgG autoantibodies. It is not known whether this represents a local mucosal response which has switched to IgG or a peripheral response which may have been initiated by peripheral antigen which homed to the colonic mucosa. The clonal distribution of IgG secreting cells and isotype switched variants in UC is not known. AIMS To investigate the clonal distribution of mucosal IgG in UC and to search for related IgG and IgA secreting cells in normal and diseased mucosa and blood in UC. To investigate characteristics which may discriminate between the mucosal and peripheral repertoire in the normal mucosa and in UC. PATIENTS Blood and normal and diseased mucosa from two patients with UC were studied. METHODS Immunoglobulin gene analysis and clone specific polymerase chain reaction were used to study the clonal distribution and characteristics of IgG and related IgA in the mucosa and blood of patients with UC. RESULTS The IgG response in the mucosa of UC patients included widespread clones of cells that were present in both the diseased mucosa and blood but that were scarce in normal mucosa. Clonally related IgA class switch variants, all IgA1, were detected but also only in the diseased mucosa and blood. This suggests that these clones home preferentially to the diseased mucosa. We showed that J(H)1 usage was characteristic of the peripheral repertoire, and that examples of J(H)1 usage were observed in mucosal IgG in UC. CONCLUSIONS Overall, these data are consistent with a model of UC in which a peripheral response is expressed and expanded in the colonic mucosa.

Recently, single-molecule imaging and photocontrol have enabled superresolution optical microscopy of cellular structures beyond Abbe's diffraction limit, extending the frontier of noninvasive imaging of structures within living cells. However, live-cell superresolution imaging has been challenged by the need to image three-dimensional (3D) structures relative to their biological context, such as the cellular membrane. We have developed a technique, termed superresolution by power-dependent active intermittency and points accumulation for imaging in nanoscale topography (SPRAIPAINT) that combines imaging of intracellular enhanced YFP (eYFP) fusions (SPRAI) with stochastic localization of the cell surface (PAINT) to image two different fluorophores sequentially with only one laser. Simple light-induced blinking of eYFP and collisional flux onto the cell surface by Nile red are used to achieve single-molecule localizations, without any antibody labeling, cell membrane permeabilization, or thiol-oxygen scavenger systems required. Here we demonstrate live-cell 3D superresolution imaging of Crescentin-eYFP, a cytoskeletal fluorescent protein fusion, colocalized with the surface of the bacterium Caulobacter crescentus using a double-helix point spread function microscope. Three-dimensional colocalization of intracellular protein structures and the cell surface with superresolution optical microscopy opens the door for the analysis of protein interactions in living cells with excellent precision (20-40 nm in 3D) over a large field of view (12 12 μm).

RNases P and MRP are ribonucleoprotein complexes involved in tRNA and rRNA processing, respectively. The RNA subunits of these two enzymes are structurally related to each other and play an essential role in the enzymatic reaction. Both of the RNAs have a highly conserved helical region, P4, which is important in the catalytic reaction. We have used a bioinformatics approach based on conserved elements to computationally analyze available genomic sequences of eukaryotic organisms and have identified a large number of novel nuclear RNase P and MRP RNA genes. For MRP RNA for instance, this investigation increases the number of known sequences by a factor of three. We present secondary structure models of many of the predicted RNAs. Although all sequences are able to fold into the consensus secondary structure of P and MRP RNAs, a striking variation in size is observed, ranging from a Nosema locustae MRP RNA of 160 nt to much larger RNAs, e.g. a Plasmodium knowlesi P RNA of 696 nt. The P and MRP RNA genes appear in tandem in some protists, further emphasizing the close evolutionary relationship of these RNAs.


Question: Albendazole is utilized for treating lymphatic filariasis.

"Integrated Strategies for Combating Africa's Neglected Tropical Diseases: A Pathway to Alleviating Poverty"
In recent years, substantial progress has been made in controlling several key tropical diseases that have a significant impact on human health [1]. This progress includes notable declines in the prevalence and incidence of neglected diseases such as lymphatic filariasis, river blindness, guinea worm, leprosy, and trachoma (Box 1) [2]. These diseases disproportionately affect the rural poor in low-income countries, often exacerbating poverty and social stigma (Box 2) [3]. Despite their long history, dating back to ancient civilizations as documented in religious and historical texts [3], these neglected tropical diseases are now facing unprecedented control measures through targeted regional programs [2–8]. In fact, the eradication of certain diseases, like guinea worm infection, is now within reach [9]. Box 2. Shared Characteristics of the Neglected Tropical Diseases          Diseases with a long historical presence, affecting humanity for centuries      Conditions that contribute to and are perpetuated by poverty      Often stigmatized in affected communities      Predominantly found in rural areas of low-income countries and unstable states      Lack of commercial interest in developing treatments for these diseases      Demonstrated success when control measures are implemented

Note: The document has been transformed to maintain its length, complexity, and semantic style while preserving its relationship to the question. The generated semantically similar document discusses the use of Albendazole for treating lymphatic filariasis within the context of integrated control strategies for neglected tropical diseases in Africa. However, the original question was not directly addressed in the provided document, so the transformation focused on maintaining the thematic context of neglected diseases and their control.

PURPOSE To assess the efficacy, dose stability, safety, and abuse potential of long-term, nightly benzodiazepine treatment of chronic disorders of disrupted nocturnal sleep. PATIENTS AND METHODS During a 12-year period, one author evaluated and treated 170 adult referrals for > or = 6 months with nightly benzodiazepine therapy for longstanding, sleep-disruptive disorders: injurious sleepwalking and sleep terrors (69); rapid eye movement sleep behavior disorder (52); chronic, severe insomnia (25); and restless legs syndrome/periodic limb movement disorder (24). RESULTS Complete/substantial control of the sleep disorders was achieved by 146 patients (86%); 8% had adverse effects requiring medication changes; 2% had relapses of alcohol or chemical abuse requiring hospitalization; another 2% at times misused their medications. A total of 136 patients received clonazepam nightly for a mean 3.5 (+/- 2.4) years, with no significant difference in inital versus final mean dose: 0.77 mg (+/- 0.46) versus 1.10 mg (+/- 0.96). Similar results were obtained with chronic alprazolam treatment and with other benzodiazepine treatments. CONCLUSION Long-term, nightly benzodiazepine treatment of injurious parasomnias and other disorders of disrupted nocturnal sleep resulted in sustained efficacy in most cases, with low risk of dosage tolerance, adverse effects, or abuse. Data from this study on the treatment of chronic, severe insomnia (a small subset of all insomnia) are not generalizable to the typical insomnia patient.

AIMS Lactic acidosis is a well recognized complication of biguanide therapy which is potentially serious. Although the prevalence of metformin-associated lactic acidosis (MALA) is much lower than that associated with phenformin, it is still being reported sporadically which raises concerns for the practising clinicians. We review the currently available world-wide data of the prevalence of MALA, the risk factors for its development and the current practical guidelines on the use of metformin to minimize the risk of this potential hazard. METHODS An extensive literature search was conducted from both Medline and Ovid (1965-98) using the following keywords: 'Type 2 diabetes mellitus', 'oral hypoglycaemic drugs', 'biguanides', 'metformin-associated lactic acidosis' and 'renal impairment'. RESULTS MALA was found to be a very rare clinical entity, being 20 times less common than phenformin-associated lactic acidosis. Amongst all the risk factors, renal impairment appears to be the major precipitating factor for the development of MALA in metformin-treated patients. We also found cases of MALA where no precipitating factors were identified and the underlying mechanism in these cases remains unclear. Practical recommendations of metformin use to minimize the risk of MALA have been listed based on previous reports. CONCLUSIONS The low prevalence of MALA is comparable to the prevalence of sulphonylurea-induced hypoglycaemia. Metformin has many beneficial metabolic effects in the management of Type 2 diabetes mellitus. Provided that the recommended guidelines for metformin use are strictly adhered to, its widespread use would be safe and the incidence of MALA will be further reduced.

BACKGROUND The case-fatality for intentional self-poisoning in the rural developing world is 10-50-fold higher than that in industrialised countries, mostly because of the use of highly toxic pesticides and plants. We therefore aimed to assess whether routine treatment with multiple-dose activated charcoal, to interrupt enterovascular or enterohepatic circulations, offers benefit compared with no charcoal in such an environment. METHODS We did an open-label, parallel group, randomised, controlled trial of six 50 g doses of activated charcoal at 4-h intervals versus no charcoal versus one 50 g dose of activated charcoal in three Sri Lankan hospitals. 4632 patients were randomised to receive no charcoal (n=1554), one dose of charcoal (n=1545), or six doses of charcoal (n=1533); outcomes were available for 4629 patients. 2338 (51%) individuals had ingested pesticides, whereas 1647 (36%) had ingested yellow oleander (Thevetia peruviana) seeds. Mortality was the primary outcome measure. Analysis was by intention to treat. The trial is registered with controlled-trials.com as ISRCTN02920054. FINDINGS Mortality did not differ between the groups. 97 (6.3%) of 1531 participants in the multiple-dose group died, compared with 105 (6.8%) of 1554 in the no charcoal group (adjusted odds ratio 0.96, 95% CI 0.70-1.33). No differences were noted for patients who took particular poisons, were severely ill on admission, or who presented early. INTERPRETATION We cannot recommend the routine use of multiple-dose activated charcoal in rural Asia Pacific; although further studies of early charcoal administration might be useful, effective affordable treatments are urgently needed.

Burkitt's lymphoma (BL) was first described 50 years ago, and the first human tumour virus Epstein–Barr virus (EBV) was discovered in BL tumours soon after. Since then, the role of EBV in the development of BL has become more and more enigmatic. Only recently have we finally begun to understand, at the cellular and molecular levels, the complex and interesting interaction of EBV with B cells that creates a predisposition for the development of BL. Here, we discuss the intertwined histories of EBV and BL and their relationship to the cofactors in BL pathogenesis: malaria and the MYC translocation.

The morphogenesis of the C. elegans embryo is largely controlled by the development of the epidermis, also known as the hypodermis, a single epithelial layer that surrounds the animal. Morphogenesis of the epidermis involves cell-cell interactions with internal tissues, such as the developing nervous system and musculature. Genetic analysis of mutants with aberrant epidermal morphology has defined multiple steps in epidermal morphogenesis. In the wild type, epidermal cells are generated on the dorsal side of the embryo among the progeny of four early embryonic blastomeres. Specification of epidermal fate is regulated by a hierarchy of transcription factors. After specification, dorsal epidermal cells rearrange, a process known as dorsal intercalation. Most epidermal cells fuse to generate multinucleate syncytia. The dorsally located epidermal sheet undergoes epiboly to enclose the rest of the embryo in a process known as ventral enclosure; this movement requires both an intact epidermal layer and substrate neuroblasts. At least three distinct types of cellular behavior underlie the enclosure of different regions of the epidermis. Following enclosure, the epidermis elongates, a process driven by coordinated cell shape changes. Epidermal actin microfilaments, microtubules, and intermediate filaments all play roles in elongation, as do body wall muscles. The final shape of the epidermis is maintained by the collagenous exoskeleton, secreted by the apical surface of the epidermis.

The toxic effects of Nerium oleander were evaluated in capuchin monkeys (Cebus apella) by examination of clinical signs, hematologic and serum chemical values, and gross and microscopic lesions. Dried and ground oleander leaves were given at intervals of 48 h in doses of 30, 7.5, and 3 mg/kg body weight. The cumulative lethal dose ranged from 30 to 60 mg/kg body weight in monkeys that were given doses of 30 and 7.5 mg/kg body weight. Monkeys that received doses of 3 mg/kg body weight (total cumulative dose: 60 mg/kg) survived. Clinical signs were vomiting, salivation, polyuria, bradycardia, vaginal hemorrhage, abortion, anorexia, constipation, loss of body weight, narcosis, restlessness, weakness, and shallow and rapid respirations. Changes in blood values were leukocytosis; neutrophilia; increased potassium, glutamic-oxalacetic transaminase, glutamic-pyruvic transaminase, blood urea nitrogen and α-globulins; reticulo-cytopenia; and decreased calcium, glucose, total serum protein, albumin, γ-globulin leve...

Hemolysates of erythrocytes from more than a quarter million people in Alabama were electrophoresed on cellulose acetate, pH 8.4, and those samples exhibiting an abnormality were also electrophoresed in citrate agar, pH 6.0. The globin chains of mutants other than Hb S and C were electrophoresed in urea-mercaptoethanol buffers at both pH 8.9 and pH 6.0, and 60 of them were also analyzed structurally. Of about 6000 samples from whites, only three contained abnormal hemoglobins--Hb D Los Angeles, Hb J Baltimore, and one unidentified. Of 249,000 samples from blacks, about 29,000 contained electrophoretically detectable abnormalities, most of them associated with Hb S or C, present in a frequency of about 9% and 3%, respectively. About 1000 samples resolved into patterns of potential clinical significance. Twenty other mutant hemoglobins were detected, in various genetic combinations in 164 kindreds; four of these-Hb Alabama, Montgomery, Titusville, and Mobile--were previously unknown. The methods used are rapid, economical, and well suited for large scale surveys. They provide highly specific characterizations of many mutant hemoglobins, and no discrepancies were found between the presumptive identifications based on these characterizations and the definitive identifications obtained from structural analyses.

BACKGROUND Diabetic nephropathy is the leading cause of end-stage renal disease in developed countries. We evaluated the renoprotective effects of dual blockade of the renin-angiotensin-aldosterone system by adding treatment with aliskiren, an oral direct renin inhibitor, to treatment with the maximal recommended dose of losartan (100 mg daily) and optimal antihypertensive therapy in patients who had hypertension and type 2 diabetes with nephropathy. METHODS We enrolled 599 patients in this multinational, randomized, double-blind study. After a 3-month, open-label, run-in period during which patients received 100 mg of losartan daily, patients were randomly assigned to receive 6 months of treatment with aliskiren (150 mg daily for 3 months, followed by an increase in dosage to 300 mg daily for another 3 months) or placebo, in addition to losartan. The primary outcome was a reduction in the ratio of albumin to creatinine, as measured in an early-morning urine sample, at 6 months. RESULTS The baseline characteristics of the two groups were similar. Treatment with 300 mg of aliskiren daily, as compared with placebo, reduced the mean urinary albumin-to-creatinine ratio by 20% (95% confidence interval, 9 to 30; P<0.001), with a reduction of 50% or more in 24.7% of the patients who received aliskiren as compared with 12.5% of those who received placebo (P<0.001). A small difference in blood pressure was seen between the treatment groups by the end of the study period (systolic, 2 mm Hg lower [P=0.07] and diastolic, 1 mm Hg lower [P=0.08] in the aliskiren group). The total numbers of adverse and serious adverse events were similar in the groups. CONCLUSIONS Aliskiren may have renoprotective effects that are independent of its blood-pressure-lowering effect in patients with hypertension, type 2 diabetes, and nephropathy who are receiving the recommended renoprotective treatment. (ClinicalTrials.gov number, NCT00097955 [ClinicalTrials.gov].).

BACKGROUND According to willingness of the Ministry of Health, Iran and presence of appropriate conditions for disease elimination, national malaria control program decided to conduct a research to clarify malaria status in 2007 and to provide required information to perform the elimination program. This review is comprised of the basis of national malaria elimination program in vision of 2025, which was started in 2010. METHODS In this descriptive study, data were analyzed by applications of different variables at district level. All districts in the three south eastern provinces, in which malaria has local transmission, were considered. Malaria cases has been determined and studied based on the national malaria surveillance system. RESULTS Since vivax malaria is predominant in Sistan & Baluchestan Province, number of vivax cases is equal to malaria positive cases approximately. The important point is that Nikshahr contains the maximum number of local vivax cases in this province and the maximum number of falciparum cases is reported from Sarbaz district. Among all districts of Hormozgan Province, no case of autochthonous falciparum was detected except in Bandar Jask and one case in Minab. There was no case of autochthonous falciparum in Kerman Province, except in Kahnoj and Ghale Ganj that each of them had one case in 2007. CONCLUSION It appears that the report of locally transmitted cases in Iran is increasing over the past few years, before starting malaria elimination plan. Since the Afghan refugees started to return to their own country so the main source of reporting of imported malaria cases reduced and local cases would be demonstrated more clearly.

Secreted Wnt proteins influence neural connectivity by regulating axon guidance, dendritic morphogenesis and synapse formation. We report a new role for Wnt and Frizzled proteins in establishing the anteroposterior polarity of the mechanosensory neurons ALM and PLM in C. elegans. Disruption of Wnt signaling leads to a complete inversion of ALM and PLM polarity: the anterior process adopts the length, branching pattern and synaptic properties of the wild-type posterior process, and vice versa. Different but overlapping sets of Wnt proteins regulate neuronal polarity in different body regions. Wnts act directly on PLM via the Frizzled LIN-17. In addition, we show that they are needed for axon branching and anteriorly directed axon growth. We also find that the retromer, a conserved protein complex that mediates transcytosis and endosome-to-Golgi protein trafficking, plays a key role in Wnt signaling. Deletion mutations of retromer subunits cause ALM and PLM polarity, and other Wnt-related defects. We show that retromer protein VPS-35 is required in Wnt-expressing cells and propose that retromer activity is needed to generate a fully active Wnt signal.


Question: Alizarin creates hydrogen bonds with residues participating in PGAM1 substrate attachment.

Phosphorylation of Tyr26 in PGAM1 Enhances Its Activity and Metabolic Benefits in Tumors by Stabilizing the Active Conformation. The intricate interplay between oncogenic signals, glycolysis, and anabolic pathways in cancer cells is not fully understood. Our previous work established that the glycolytic enzyme phosphoglycerate mutase 1 (PGAM1) governs anabolic processes by managing intracellular concentrations of 3-phosphoglycerate and 2-phosphoglycerate. In this study, we unveil a novel mechanism where the phosphorylation of tyrosine 26 (Y26) in PGAM1 amplifies its activation by displacing the inhibitory residue E19, which blocks the active site. This action stabilizes the binding of the cofactor 2,3-bisphosphoglycerate and triggers the phosphorylation of H11. We present the crystal structure of PGAM1 with H11 phosphorylation and observe that phospho-H11 boosts PGAM1 activity by facilitating the binding of the substrate 3-phosphoglycerate. Furthermore, Y26 phosphorylation of PGAM1 is prevalent in human cancer cells and is crucial for regulating 3-phosphoglycerate and 2-phosphoglycerate levels, which in turn supports cancer cell proliferation and tumor expansion. Given that PGAM1 is negatively regulated by TP53 at the transcriptional level and is often upregulated in human cancers, our findings indicate that Y26 phosphorylation constitutes a supplementary acute mechanism driving the upregulation of phosphoglycerate mutase 1.

BACKGROUND In systemic amyloidosis the distribution and progression of disease have been difficult to monitor, because they can be demonstrated only by biopsy. Serum amyloid P component (SAP) is a normal circulating plasma protein that is deposited on amyloid fibrils because of its specific binding affinity for them. We investigated whether labeled SAP could be used to locate amyloid deposits. METHODS Purified human SAP labeled with iodine-123 was given intravenously to 50 patients with biopsy-proved systemic amyloidosis--25 with the AL (primary) type and 25 with the AA (secondary) type--and to 26 control patients with disease and 10 healthy subjects. Whole-body images and regional views were obtained after 24 hours and read in a blinded fashion. RESULTS In the patients with amyloidosis the 123I-SAP was localized rapidly and specifically in amyloid deposits. The scintigraphic images obtained were characteristic and appeared to identify the extent of amyloid deposition in all 50 patients. There was no uptake of the 123I-SAP by the control patients and the healthy subjects. In all patients with AA amyloidosis the spleen was affected, whereas the scans showed uptake in the heart, skin, carpal region, and bone marrow only in patients with the AL type. Positive images were seen in six patients in whom biopsies had been negative or unsuccessful; in all six, amyloid was subsequently found on biopsy or at autopsy. Progressive amyloid deposition was observed in 9 of 11 patients studied serially. CONCLUSIONS Scintigraphy after the injection of 123I-SAP can be used for diagnosing, locating, and monitoring the extent of systemic amyloidosis.

Subdividing proliferating tissues into compartments is an evolutionarily conserved strategy of animal development [1-6]. Signals across boundaries between compartments can result in local expression of secreted proteins organizing growth and patterning of tissues [1-6]. Sharp and straight interfaces between compartments are crucial for stabilizing the position of such organizers and therefore for precise implementation of body plans. Maintaining boundaries in proliferating tissues requires mechanisms to counteract cell rearrangements caused by cell division; however, the nature of such mechanisms remains unclear. Here we quantitatively analyzed cell morphology and the response to the laser ablation of cell bonds in the vicinity of the anteroposterior compartment boundary in developing Drosophila wings. We found that mechanical tension is approximately 2.5-fold increased on cell bonds along this compartment boundary as compared to the remaining tissue. Cell bond tension is decreased in the presence of Y-27632 [7], an inhibitor of Rho-kinase whose main effector is Myosin II [8]. Simulations using a vertex model [9] demonstrate that a 2.5-fold increase in local cell bond tension suffices to guide the rearrangement of cells after cell division to maintain compartment boundaries. Our results provide a physical mechanism in which the local increase in Myosin II-dependent cell bond tension directs cell sorting at compartment boundaries.

We propose a concept for the folding and self-assembly of the pore-forming TatA complex from the Twin-arginine translocase and of other membrane proteins based on electrostatic "charge zippers. " Each subunit of TatA consists of a transmembrane segment, an amphiphilic helix (APH), and a C-terminal densely charged region (DCR). The sequence of charges in the DCR is complementary to the charge pattern on the APH, suggesting that the protein can be "zipped up" by a ladder of seven salt bridges. The length of the resulting hairpin matches the lipid bilayer thickness, hence a transmembrane pore could self-assemble via intra- and intermolecular salt bridges. The steric feasibility was rationalized by molecular dynamics simulations, and experimental evidence was obtained by monitoring the monomer-oligomer equilibrium of specific charge mutants. Similar "charge zippers" are proposed for other membrane-associated proteins, e.g., the biofilm-inducing peptide TisB, the human antimicrobial peptide dermcidin, and the pestiviral E(RNS) protein.

The initiation and progression of adult-onset periodontitis has been associated with infection of the gingival sulcus by Porphyromonas gingivalis. This organism utilizes a multitude of virulence factors to evade host defenses as it establishes itself as one of the predominant pathogens in periodontal pockets. A feature common to many other oral pathogens is the production of ammonia due to its protective effect during acidic cleansing cycles in the mouth. Additionally, ammonia production by P. gingivalis has been proposed as a virulence factor due to its negative effects on neutrophil function. In this study, we describe the first purification of a peptidylarginine deiminase (PAD) from a prokaryote. PAD exhibits biochemical characteristics and properties that suggest that it may be a virulence agent. PAD deiminates the guanidino group of carboxyl-terminal arginine residues on a variety of peptides, including the vasoregulatory peptide-hormone bradykinin, to yield ammonia and a citrulline residue. The soluble protein has an apparent mass of 46 kDa, while the DNA sequence predicts a full-length protein of 61.7 kDa. PAD is optimally active at 55 degrees C, stable at low pH, and shows the greatest activity above pH 9.0. Interestingly, in the presence of stabilizing factors, PAD is resistant to limited proteolysis and retains significant activity after short-term boiling. We propose that PAD, acting in concert with arginine-specific proteinases from P. gingivalis, promotes the growth of the pathogen in the periodontal pocket, initially by enhancing its survivability and then by assisting the organism in its circumvention of host humoral defenses.

The pH dependence of the quaternary structure of pyruvate decarboxylase from yeast was studied in the range 6.2 less than pH less than 8.4. There is an equilibrium with a midpoint around pH 7.5 between tetramers and dimers, and the catalytic activity of the enzyme depends on the volume fraction of tetramer. This equilibrium may provide an additional regulating mechanism besides substrate activation since accumulation of pyruvate would lead to a reduction in pH and hence an increase of the concentration of the catalytically active tetramer. Radiation damage during the X-ray scattering experiments results in a shift of this equilibrium and in the formation of octamers. These effects could be circumvented and analyzed using experimental and data processing methods which can be readily applied to other radiation-sensitive systems. The low-resolution shapes of the dimers and tetramers were determined from the scattering curves using spherical harmonics. The results indicate that a conformational change must occur in the dimers upon formation of the tetramers, in agreement with earlier circular dichroism measurements.

Comparative protein structure modeling predicts the three-dimensional structure of a given protein sequence (target) based primarily on its alignment to one or more proteins of known structure (templates). The prediction process consists of fold assignment, target-template alignment, model building, and model evaluation. This unit describes how to calculate comparative models using the program MODELLER and how to use the ModBase database of such models, and discusses all four steps of comparative modeling, frequently observed errors, and some applications. Modeling lactate dehydrogenase from Trichomonas vaginalis (TvLDH) is described as an example. The download and installation of the MODELLER software is also described. © 2016 by John Wiley & Sons, Inc.

Live imaging of the actin cytoskeleton is crucial for the study of many fundamental biological processes, but current approaches to visualize actin have several limitations. Here we describe Lifeact, a 17-amino-acid peptide, which stained filamentous actin (F-actin) structures in eukaryotic cells and tissues. Lifeact did not interfere with actin dynamics in vitro and in vivo and in its chemically modified peptide form allowed visualization of actin dynamics in nontransfectable cells.

Although drugs are intended to be selective, at least some bind to several physiological targets, explaining side effects and efficacy. Because many drug-target combinations exist, it would be useful to explore possible interactions computationally. Here we compared 3,665 US Food and Drug Administration (FDA)-approved and investigational drugs against hundreds of targets, defining each target by its ligands. Chemical similarities between drugs and ligand sets predicted thousands of unanticipated associations. Thirty were tested experimentally, including the antagonism of the beta(1) receptor by the transporter inhibitor Prozac, the inhibition of the 5-hydroxytryptamine (5-HT) transporter by the ion channel drug Vadilex, and antagonism of the histamine H(4) receptor by the enzyme inhibitor Rescriptor. Overall, 23 new drug-target associations were confirmed, five of which were potent (<100 nM). The physiological relevance of one, the drug N,N-dimethyltryptamine (DMT) on serotonergic receptors, was confirmed in a knockout mouse. The chemical similarity approach is systematic and comprehensive, and may suggest side-effects and new indications for many drugs.

Chromosome segregation during mitosis requires assembly of the kinetochore complex at the centromere. Kinetochore assembly depends on specific recognition of the histone variant CENP-A in the centromeric nucleosome by centromere protein C (CENP-C). We have defined the determinants of this recognition mechanism and discovered that CENP-C binds a hydrophobic region in the CENP-A tail and docks onto the acidic patch of histone H2A and H2B. We further found that the more broadly conserved CENP-C motif uses the same mechanism for CENP-A nucleosome recognition. Our findings reveal a conserved mechanism for protein recruitment to centromeres and a histone recognition mode whereby a disordered peptide binds the histone tail through hydrophobic interactions facilitated by nucleosome docking.

A new technique for the automated tracing of protein chains in experimental electron-density maps is described. The technique relies on the repeated application of an oriented electron-density likelihood target function to identify likely C(alpha) positions. This function is applied both in the location of a few promising ;seed' positions in the map and to grow those initial C(alpha) positions into extended chain fragments. Techniques for assembling the chain fragments into an initial chain trace are discussed.


Question: Every hematopoietic stem cell segregates its chromosomes haphazardly.

Hematopoietic Stem Cells Exhibit Random Chromosome Segregation and Do Not Retain BrdU Labels
Theories suggest that stem cells may asymmetrically segregate chromosomes during self-renewal, ensuring that older, or 'immortal', DNA strands are conserved in daughter stem cells while newly synthesized strands are allocated to differentiating cells. Another hypothesis posits that stem cells maintain DNA labels, such as 5-bromo-2-deoxyuridine (BrdU), either through asymmetric chromosome segregation or slow division rates. However, the specificity of BrdU-label-retaining cells as true stem cells has not been substantiated in any tissue, and the 'immortal strand hypothesis' has not been rigorously tested using definitive stem cell markers. We conducted experiments to evaluate these hypotheses in hematopoietic stem cells (HSCs), which can be highly purified using established markers. We administered BrdU to newborn mice, mice treated with cyclophosphamide and granulocyte colony-stimulating factor, and normal adult mice for 4 to 10 days, followed by a 70-day BrdU-free period. Our findings revealed that less than 6% of HSCs retained BrdU and less than 0.5% of all BrdU-retaining hematopoietic cells were HSCs, indicating that BrdU is neither specific nor sensitive as an HSC marker. Further, using sequential administration of 5-chloro-2-deoxyuridine and 5-iodo-2-deoxyuridine, we demonstrated that all HSCs randomly segregate their chromosomes. Cultured individual HSCs showed no evidence of asymmetric label segregation. These results indicate that HSCs cannot be accurately identified by BrdU-label retention and do not retain older DNA strands upon division, suggesting that these traits are not universal characteristics of stem cells.

Genome endoreduplication during mammalian development is a rare event for which the mechanism is unknown. It first appears when fibroblast growth factor 4 (FGF4) deprivation induces differentiation of trophoblast stem (TS) cells into the nonproliferating trophoblast giant (TG) cells required for embryo implantation. Here we show that RO3306 inhibition of cyclin-dependent protein kinase 1 (CDK1), the enzyme required to enter mitosis, induced differentiation of TS cells into TG cells. In contrast, RO3306 induced abortive endoreduplication and apoptosis in embryonic stem cells, revealing that inactivation of CDK1 triggers endoreduplication only in cells programmed to differentiate into polyploid cells. Similarly, FGF4 deprivation resulted in CDK1 inhibition by overexpressing two CDK-specific inhibitors, p57/KIP2 and p21/CIP1. TS cell mutants revealed that p57 was required to trigger endoreduplication by inhibiting CDK1, while p21 suppressed expression of the checkpoint protein kinase CHK1, thereby preventing induction of apoptosis. Furthermore, Cdk2(-/-) TS cells revealed that CDK2 is required for endoreduplication when CDK1 is inhibited. Expression of p57 in TG cells was restricted to G-phase nuclei to allow CDK activation of S phase. Thus, endoreduplication in TS cells is triggered by p57 inhibition of CDK1 with concomitant suppression of the DNA damage response by p21.

Fucci technology makes possible the distinction between live cells in the G(1) and S/G(2)/M phases by dual-color imaging. This technology relies upon ubiquitylation-mediated proteolysis, and transgenic mice expressing Fucci provide a powerful model system with which to study the coordination of the cell cycle and development. The mice were initially generated using the CAG promoter; lines expressing the G(1) and S/G(2)/M phase probes that emitted orange (mKO2) and green (mAG) fluorescence, respectively, were separately constructed. Owing to cell type-biased strength of the CAG promoter as well as the positional effects of random transgenesis, however, we noticed some variability in Fucci expression levels. To control more reliably the expression of cell cycle probes, we used different genetic approaches to create two types of reporter mouse lines with Fucci2 and Rosa26 transcriptional machinery. Fucci2 is a recently developed Fucci derivative, which emits red (mCherry) and green (mVenus) fluorescence and provides better color contrast than Fucci. A new transgenic line, R26p-Fucci2, utilizes the Rosa26 promoter and harbors the G(1) and S/G(2)/M phase probes in a single transgene to preserve their co-inheritance. In the other R26R-Fucci2 approach, the two probes are incorporated into Rosa26 locus conditionally. The Cre-mediated loxP recombination technique thus allows researchers to design cell-type-specific Fucci2 expression. By performing time-lapse imaging experiments using R26p-Fucci2 and R26-Fucci2 in which R26R-Fucci2 had undergone germline loxP recombination, we demonstrated the great promise of these mouse reporters for studying cell cycle behavior in vivo.

Imprinting is an epigenetic modification leading to monoallelic expression of some genes, and disrupted imprinting is believed to be a barrier to human stem cell transplantation, based on studies that suggest that epigenetic marks are unstable in mouse embryonic germ (EG) and embryonic stem (ES) cells. However, stem cell imprinting has not previously been examined directly in humans. We found that three imprinted genes, TSSC5, H19, and SNRPN, show monoallelic expression in in vitro differentiated human EG-derived cells, and a fourth gene, IGF2, shows partially relaxed imprinting at a ratio from 4:1 to 5:1, comparable to that found in normal somatic cells. In addition, we found normal methylation of an imprinting control region (ICR) that regulates H19 and IGF2 imprinting, suggesting that imprinting may not be a significant epigenetic barrier to human EG cell transplantation. Finally, we were able to construct an in vitro mouse model of genomic imprinting, by generating EG cells from 8.5-day embryos of an interspecific cross, in which undifferentiated cells show biallelic expression and acquire preferential parental allele expression after differentiation. This model should allow experimental manipulation of epigenetic modifications of cultured EG cells that may not be possible in human stem cell studies.

Polyploidization is a natural process that frequently accompanies differentiation; its deregulation is linked to genomic instability and cancer. Despite its relevance, why cells select different polyploidization mechanisms is unknown. Here we report a systematic genetic analysis of endomitosis, a process in which megakaryocytes become polyploid by entering mitosis but aborting anaphase. Whereas ablation of the APC/C cofactor Cdc20 results in mitotic arrest and severe thrombocytopenia, lack of the kinases Aurora-B, Cdk1, or Cdk2 does not affect megakaryocyte polyploidization or platelet levels. Ablation of Cdk1 forces a switch to endocycles without mitosis, whereas polyploidization in the absence of Cdk1 and Cdk2 occurs in the presence of aberrant re-replication events. Importantly, ablation of these kinases rescues the defects in Cdc20 null megakaryocytes. These findings suggest that endomitosis can be functionally replaced by alternative polyploidization mechanisms in vivo and provide the cellular basis for therapeutic approaches aimed to discriminate mitotic and polyploid cells.

Centromeres are heterochromatic in many organisms, but the mitotic function of this silent chromatin remains unknown. During cell division, newly replicated sister chromatids must cohere until anaphase when Scc1/Rad21-mediated cohesion is destroyed. In metazoans, chromosome arm cohesins dissociate during prophase, leaving centromeres as the only linkage before anaphase. It is not known what distinguishes centromere cohesion from arm cohesion. Fission yeast Swi6 (a Heterochromatin protein 1 counterpart) is a component of silent heterochromatin. Here we show that this heterochromatin is specifically required for cohesion between sister centromeres. Swi6 is required for association of Rad21-cohesin with centromeres but not along chromosome arms and, thus, acts to distinguish centromere from arm cohesion. Therefore, one function of centromeric heterochromatin is to attract cohesin, thereby ensuring sister centromere cohesion and proper chromosome segregation.

Despite genetic heterogeneity, myelodysplastic syndromes (MDSs) share features of cytological dysplasia and ineffective hematopoiesis. We report that a hallmark of MDSs is activation of the NLRP3 inflammasome, which drives clonal expansion and pyroptotic cell death. Independent of genotype, MDS hematopoietic stem and progenitor cells (HSPCs) overexpress inflammasome proteins and manifest activated NLRP3 complexes that direct activation of caspase-1, generation of interleukin-1β (IL-1β) and IL-18, and pyroptotic cell death. Mechanistically, pyroptosis is triggered by the alarmin S100A9 that is found in excess in MDS HSPCs and bone marrow plasma. Further, like somatic gene mutations, S100A9-induced signaling activates NADPH oxidase (NOX), increasing levels of reactive oxygen species (ROS) that initiate cation influx, cell swelling, and β-catenin activation. Notably, knockdown of NLRP3 or caspase-1, neutralization of S100A9, and pharmacologic inhibition of NLRP3 or NOX suppress pyroptosis, ROS generation, and nuclear β-catenin in MDSs and are sufficient to restore effective hematopoiesis. Thus, alarmins and founder gene mutations in MDSs license a common redox-sensitive inflammasome circuit, which suggests new avenues for therapeutic intervention.

Autophagy is a constitutive lysosomal catabolic pathway that degrades damaged organelles and protein aggregates. Stem cells are characterized by self-renewal, pluripotency, and quiescence; their long life span, limited capacity to dilute cellular waste and spent organelles due to quiescence, along with their requirement for remodeling in order to differentiate, all suggest that they require autophagy more than other cell types. Here, we review the current literature on the role of autophagy in embryonic and adult stem cells, including hematopoietic, mesenchymal, and neuronal stem cells, highlighting the diverse and contrasting roles autophagy plays in their biology. Furthermore, we review the few studies on stem cells, lysosomal activity, and autophagy. Novel techniques to detect autophagy in primary cells are required to study autophagy in different stem cell types. These will help to elucidate the importance of autophagy in stem cells during transplantation, a promising therapeutic approach for many diseases.

Mitochondria have a major role in energy production via oxidative phosphorylation, which is dependent on the expression of critical genes encoded by mitochondrial (mt)DNA. Mutations in mtDNA can cause fatal or severely debilitating disorders with limited treatment options. Clinical manifestations vary based on mutation type and heteroplasmy (that is, the relative levels of mutant and wild-type mtDNA within each cell). Here we generated genetically corrected pluripotent stem cells (PSCs) from patients with mtDNA disease. Multiple induced pluripotent stem (iPS) cell lines were derived from patients with common heteroplasmic mutations including 3243A>G, causing mitochondrial encephalomyopathy and stroke-like episodes (MELAS), and 8993T>G and 13513G>A, implicated in Leigh syndrome. Isogenic MELAS and Leigh syndrome iPS cell lines were generated containing exclusively wild-type or mutant mtDNA through spontaneous segregation of heteroplasmic mtDNA in proliferating fibroblasts. Furthermore, somatic cell nuclear transfer (SCNT) enabled replacement of mutant mtDNA from homoplasmic 8993T>G fibroblasts to generate corrected Leigh-NT1 PSCs. Although Leigh-NT1 PSCs contained donor oocyte wild-type mtDNA (human haplotype D4a) that differed from Leigh syndrome patient haplotype (F1a) at a total of 47 nucleotide sites, Leigh-NT1 cells displayed transcriptomic profiles similar to those in embryo-derived PSCs carrying wild-type mtDNA, indicative of normal nuclear-to-mitochondrial interactions. Moreover, genetically rescued patient PSCs displayed normal metabolic function compared to impaired oxygen consumption and ATP production observed in mutant cells. We conclude that both reprogramming approaches offer complementary strategies for derivation of PSCs containing exclusively wild-type mtDNA, through spontaneous segregation of heteroplasmic mtDNA in individual iPS cell lines or mitochondrial replacement by SCNT in homoplasmic mtDNA-based disease.

Over 70% of diffuse intrinsic pediatric gliomas, an aggressive brainstem tumor, harbor heterozygous mutations that create a K27M amino acid substitution (methionine replaces lysine 27) in the tail of histone H3.3. The role of the H3.3K27M mutation in tumorigenesis is not fully understood. Here, we use a human embryonic stem cell system to model this tumor. We show that H3.3K27M expression synergizes with p53 loss and PDGFRA activation in neural progenitor cells derived from human embryonic stem cells, resulting in neoplastic transformation. Genome-wide analyses indicate a resetting of the transformed precursors to a developmentally more primitive stem cell state, with evidence of major modifications of histone marks at several master regulator genes. Drug screening assays identified a compound targeting the protein menin as an inhibitor of tumor cell growth in vitro and in mice.

DNA replication in mammals is regulated via the coordinate firing of clusters of replicons that duplicate megabase-sized chromosome segments at specific times during S-phase. Cytogenetic studies show that these "replicon clusters" coalesce as subchromosomal units that persist through multiple cell generations, but the molecular boundaries of such units have remained elusive. Moreover, the extent to which changes in replication timing occur during differentiation and their relationship to transcription changes has not been rigorously investigated. We have constructed high-resolution replication-timing profiles in mouse embryonic stem cells (mESCs) before and after differentiation to neural precursor cells. We demonstrate that chromosomes can be segmented into multimegabase domains of coordinate replication, which we call "replication domains," separated by transition regions whose replication kinetics are consistent with large originless segments. The molecular boundaries of replication domains are remarkably well conserved between distantly related ESC lines and induced pluripotent stem cells. Unexpectedly, ESC differentiation was accompanied by the consolidation of smaller differentially replicating domains into larger coordinately replicated units whose replication time was more aligned to isochore GC content and the density of LINE-1 transposable elements, but not gene density. Replication-timing changes were coordinated with transcription changes for weak promoters more than strong promoters, and were accompanied by rearrangements in subnuclear position. We conclude that replication profiles are cell-type specific, and changes in these profiles reveal chromosome segments that undergo large changes in organization during differentiation. Moreover, smaller replication domains and a higher density of timing transition regions that interrupt isochore replication timing define a novel characteristic of the pluripotent state.


Question: ACE inhibitors are linked to a heightened chance of practical renal inadequacy.

Renal Function and the Use of Angiotensin Converting Enzyme Inhibitors: A Comprehensive Review for Healthcare Professionals. Angiotensin converting enzyme (ACE) inhibitors have become a cornerstone in the pharmacological management of hypertension and have expanded their role to include the long-term treatment of congestive heart failure (CHF), as well as diabetic and non-diabetic renal diseases. While ACE inhibitors often enhance renal blood flow (RBF) and sodium excretion in CHF patients and slow down the progression of chronic kidney disease, their usage can also lead to a condition known as "functional renal insufficiency" or hyperkalemia. This acute renal failure (ARF) typically manifests soon after initiating ACE inhibitor therapy, although it may also occur after extended periods of treatment, even without prior adverse effects. ARF is most likely to develop in scenarios where renal perfusion is compromised due to a significant drop in mean arterial pressure (MAP) or when glomerular filtration rate (GFR) is heavily reliant on angiotensin II (Ang II). Factors predicting a negative hemodynamic impact of ACE inhibitors in CHF patients include pre-existing hypotension and low cardiac filling pressures. The GFR is particularly dependent on Ang II during conditions of extracellular fluid (ECF) volume depletion, severe bilateral renal artery stenosis, or stenosis in a dominant or single kidney, such as in renal transplant recipients. Recognizing the pathophysiological mechanisms and common risk factors for ACE inhibitor-induced functional ARF is crucial, as preventive measures exist that could allow for a broader and safer application of these drugs. Under normal physiological conditions, renal autoregulation maintains a stable RBF and GFR across a wide MAP range, which is modulated by Ang II and the sympathetic nervous system. When renal perfusion pressure decreases (for instance, during ...

Strict blood pressure (BP) control is reportedly important for the management of hypertensive patients with chronic kidney disease (CKD). The purpose of this cross-sectional study was to examine whether the variables of ambulatory BP and the heart rate (HR) profile, central hemodynamics, and arterial stiffness were closely related to the renal function parameters (urine albumin excretion rate [UACR] and estimated glomerular filtration rate [eGFR]) observed in 25 consecutive hospitalized hypertensive patients with CKD. There were significant positive relationships between UACR and 24-hour, daytime, and nighttime ambulatory systolic BP. In addition, there were significant negative relationships between UACR and 24-hour and daytime HR variability. The circulating B-type natriuretic peptide level and hemoglobin A1c were also positively related to UACR. With respect to eGFR, although the 24-hour and nighttime HR variability were positively associated with eGFR, the circulating pentosidine and nighttime HR had a negative relationship with eGFR. On the other hand, central hemodynamics and arterial stiffness did not exhibit any significant association with renal function parameters. These results indicate that ambulatory BP and the HR profile are closely modulated by renal function deterioration. Further studies are needed to investigate the causal relationship between ambulatory BP and the HR profile and renal function parameters in hypertensive patients with CKD.

Obesity is associated with higher mortality in the general population, but this association is reversed in patients on dialysis. The nature of the relationship of obesity with adverse clinical outcomes in nondialysis-dependent CKD and the putative interaction of the severity of disease with this association are unclear. We analyzed data from a nationally representative cohort of 453,946 United States veterans with eGFR<60 ml/min per 1.73 m(2). The associations of body mass index categories (<20, 20 to <25, 25 to <30, 30 to <35, 35 to <40, 40 to <45, 45 to <50, and ≥50 kg/m(2)) with all-cause mortality and disease progression (using multiple definitions, including incidence of ESRD, doubling of serum creatinine, and the slopes of eGFR) were examined in Cox proportional hazards models and logistic regression models. Multivariable adjustments were made for age, race, comorbidities and medications, and baseline eGFR. Body mass index showed a relatively consistent U-shaped association with clinical outcomes, with the best outcomes observed in overweight and mildly obese patients. Body mass index levels <25 kg/m(2) were associated with worse outcomes in all patients, independent of severity of CKD. Body mass index levels ≥35 kg/m(2) were associated with worse outcomes in patients with earlier stages of CKD, but this association was attenuated in those patients with eGFR<30 ml/min per 1.73 m(2). Thus, until clinical trials establish the ideal body mass index, a cautious approach to weight management is warranted in this patient population.

The National High Blood Pressure Education Program Coordinating Committee published its first statement on the primary prevention of hypertension in 1993. This article updates the 1993 report, using new and further evidence from the scientific literature. Current recommendations for primary prevention of hypertension involve a population-based approach and an intensive targeted strategy focused on individuals at high risk for hypertension. These 2 strategies are complementary and emphasize 6 approaches with proven efficacy for prevention of hypertension: engage in moderate physical activity; maintain normal body weight; limit alcohol consumption; reduce sodium intake; maintain adequate intake of potassium; and consume a diet rich in fruits, vegetables, and low-fat dairy products and reduced in saturated and total fat. Applying these approaches to the general population as a component of public health and clinical practice can help prevent blood pressure from increasing and can help decrease elevated blood pressure levels for those with high normal blood pressure or hypertension.

OBJECTIVES To investigate the association between antidepressant treatment and risk of several potential adverse outcomes in older people with depression and to examine risks by class of antidepressant, duration of use, and dose. DESIGN Cohort study of people aged 65 and over diagnosed as having depression. SETTING 570 general practices in the United Kingdom supplying data to the QResearch primary care database. PARTICIPANTS 60,746 patients diagnosed as having a new episode of depression between the ages of 65 and 100 years from 1 January 1996 to 31 December 2007 and followed up until 31 December 2008. MAIN OUTCOME MEASURES Hazard ratios associated with antidepressant use for all cause mortality, attempted suicide/self harm, myocardial infarction, stroke/transient ischaemic attack, falls, fractures, upper gastrointestinal bleeding, epilepsy/seizures, road traffic accidents, adverse drug reactions, and hyponatraemia, adjusted for a range of potential confounding variables. Hazard ratios were calculated for antidepressant class (tricyclic and related antidepressants, selective serotonin reuptake inhibitors, other antidepressants), dose, and duration of use and for commonly prescribed individual drugs. RESULTS 54,038 (89.0%) patients received at least one prescription for an antidepressant during follow-up. A total of 1,398,359 antidepressant prescriptions were issued: 764,659 (54.7%) for selective serotonin reuptake inhibitors, 442,192 (31.6%) for tricyclic antidepressants, 2203 (0.2%) for monoamine oxidase inhibitors, and 189,305 (13.5%) for the group of other antidepressants. The associations with the adverse outcomes differed significantly between the antidepressant classes for seven outcomes. Selective serotonin reuptake inhibitors were associated with the highest adjusted hazard ratios for falls (1.66, 95% confidence interval 1.58 to 1.73) and hyponatraemia (1.52, 1.33 to 1.75) compared with when antidepressants were not being used. The group of other antidepressants was associated with the highest adjusted hazard ratios for all cause mortality (1.66, 1.56 to 1.77), attempted suicide/self harm (5.16, 3.90 to 6.83), stroke/transient ischaemic attack (1.37, 1.22 to 1.55), fracture (1.64, 1.46 to 1.84), and epilepsy/seizures (2.24, 1.60 to 3.15), compared with when antidepressants were not being used. Tricyclic antidepressants did not have the highest hazard ratio for any of the outcomes. Significantly different associations also existed between the individual drugs for the same seven outcomes; trazodone (tricyclic antidepressant), mirtazapine, and venlafaxine (both in the group of other antidepressants) were associated with the highest rates for some of these outcomes. Absolute risks over 1 year for all cause mortality were 7.04% for patients while not taking antidepressants, 8.12% for those taking tricyclic antidepressants, 10.61% for selective serotonin reuptake inhibitors, and 11.43% for other antidepressants. CONCLUSIONS Selective serotonin reuptake inhibitors and drugs in the group of other antidepressants were associated with an increased risk of several adverse outcomes compared with tricyclic antidepressants. Among individual drugs, trazodone, mirtazapine, and venlafaxine were associated with the highest risks for some outcomes. As this is an observational study, it is susceptible to confounding by indication, channelling bias, and residual confounding, so differences in characteristics between patients prescribed different antidepressant drugs that could account for some of the associations between the drugs and the adverse outcomes may remain. Further research is needed to confirm these findings, but the risks and benefits of different antidepressants should be carefully evaluated when these drugs are prescribed to older people.

1. Cost-Effectiveness Analysis as a Guide to Resource Allocation in Health: Roles and Limitations 2. Theoretical Foundations of Cost-Effectiveness Analysis 3. Framing and Designing the Cost-Effectiveness Analysis 4. Identifying and Valuing Outcomes 5. Assessing the Effectiveness of Health Interventions 6. Estimating Costs in Cost-Effectiveness Analysis 7. Time Preference 8. Reflecting Uncertainty in Cost-Effectiveness Analysis 9. Reporting Cost-Effectiveness Studies and Results Appendix A: Summary of Recommendations for the Reference Case Appendix B: Cost-Effectiveness of Strategies to Prevent Neural Tube Defects Appendix C: The Cost-Effectiveness of Dietary and Pharmacologic Therapy for Cholesterol Reduction in Adults

OBJECTIVE One of the theories involved in the pathogenesis of pregnancy induced hypertension involves salt and water retention. We aimed to measure the proenzyme convertase corin, responsible for pro-atrial natriuretic peptide (ANP) cleavage to active ANP, in plasma of hypertensive pregnant females. STUDY DESIGN Sixty pregnant females suffering from pregnancy induced hypertension in second and third trimesters of pregnancy were compared to twenty eight healthy pregnant females of the same gestational period. Concomitant urine and plasma samples were collected for the determination of some biochemical parameters. Plasma soluble corin and N-terminal (NT) pro-ANP (1-98) values were determined in both groups using enzyme immunoassays. RESULTS Plasma soluble corin mean value was significantly higher in the patient group compared to the control group. Upon dividing the patient group according to blood pressure, plasma NT pro-ANP showed significantly higher mean value in the group with blood pressure⩾140/90mmHg compared to the group with blood pressure<140/90mmHg and control group. CONCLUSIONS High plasma soluble corin and NT pro-ANP values in hypertensive pregnant females particularly those with blood pressure⩾140/90mmHg speculates an ANP receptor/ post receptor signaling defect, which would aggravate the pregnancy induced hypertensive state.

CONTEXT Fatal adverse events (FAEs) have been reported in cancer patients treated with the widely used angiogenesis inhibitor bevacizumab in combination with chemotherapy. Currently, the role of bevacizumab in treatment-related mortality is not clear. OBJECTIVE To perform a systematic review and meta-analysis of published randomized controlled trials (RCTs) to determine the overall risk of FAEs associated with bevacizumab. DATA SOURCES PubMed, EMBASE, and Web of Science databases as well as abstracts presented at American Society of Clinical Oncology conferences from January 1966 to October 2010 were searched to identify relevant studies. STUDY SELECTION AND DATA EXTRACTION Eligible studies included prospective RCTs in which bevacizumab in combination with chemotherapy or biological therapy was compared with chemotherapy or biological therapy alone. Summary incidence rates, relative risks (RRs), and 95% confidence intervals (CIs) were calculated using fixed- or random-effects models. DATA SYNTHESIS A total of 10,217 patients with a variety of advanced solid tumors from 16 RCTs were included in the analysis. The overall incidence of FAEs with bevacizumab was 2.5% (95% CI, 1.7%-3.9%). Compared with chemotherapy alone, the addition of bevacizumab was associated with an increased risk of FAEs, with an RR of 1.46 (95% CI, 1.09-1.94; P = .01; incidence, 2.5% vs 1.7%). This association varied significantly with chemotherapeutic agents (P = .045) but not with tumor types (P = .13) or bevacizumab doses (P = .16). Bevacizumab was associated with an increased risk of FAEs in patients receiving taxanes or platinum agents (RR, 3.49; 95% CI, 1.82-6.66; incidence, 3.3% vs 1.0%) but was not associated with increased risk of FAEs when used in conjunction with other agents (RR, 0.85; 95% CI, 0.25-2.88; incidence, 0.8% vs 0.9%). The most common causes of FAEs were hemorrhage (23.5%), neutropenia (12.2%), and gastrointestinal tract perforation (7.1%). CONCLUSION In a meta-analysis of RCTs, bevacizumab in combination with chemotherapy or biological therapy, compared with chemotherapy alone, was associated with increased treatment-related mortality.

Cardiovascular mortality is 10 to 20 times increased in patients with chronic renal failure (CRF). Risk factors for atherosclerosis are abundant in patients with CRF. However, the pathogenesis of cardiovascular disease in CRF remains to be elucidated. The effect of CRF on the development of atherosclerosis in apolipoprotein E-deficient male mice was examined. Seven-week-old mice underwent 5/6 nephrectomy (CRF, n = 28), unilateral nephrectomy (UNX, n = 24), or no surgery (n = 23). Twenty-two weeks later, CRF mice showed increased aortic plaque area fraction (0.266 +/- 0.033 versus 0.045 +/- 0.006; P < 0.001), aortic cholesterol content (535 +/- 62 versus 100 +/- 9 nmol/cm(2) intimal surface area; P < 0.001), and aortic root plaque area (205,296 +/- 22,098 versus 143,662 +/- 13,302 micro m(2); P < 0.05) as compared with no-surgery mice; UNX mice showed intermediate values. The plaques from uremic mice contained CD11b-positive macrophages and showed strong staining for nitrotyrosine. Systolic BP and plasma homocysteine concentrations were similar in uremic and nonuremic mice. Plasma urea and cholesterol concentrations were elevated 2.6-fold (P < 0.001) and 1.5-fold (P < 0.001) in CRF compared with no-surgery mice. Both variables correlated with aortic plaque area fraction (r(2) = 0.5, P < 0.001 and r(2) = 0.3, P < 0.001, respectively) and with each other (r(2) = 0.5, P < 0.001). On multiple linear regression analysis, only plasma urea was a significant predictor of aortic plaque area fraction. In conclusion, the present findings suggest that uremia markedly accelerates atherogenesis in apolipoprotein E-deficient mice. This effect could not be fully explained by changes in BP, plasma homocysteine levels, or total plasma cholesterol concentrations. Thus, the CRF apolipoprotein E-deficient mouse is a new model for studying the pathogenesis of accelerated atherosclerosis in uremia.

AIMS Vascular endothelial dysfunction and inflammation are hallmarks of atherosclerosis. Krüppel-like factor 2 (KLF2) is a key mediator of anti-inflammatory and anti-atherosclerotic properties of the endothelium. However, little is known of the molecular mechanisms for regulating KLF2 transcriptional activation. METHODS AND RESULTS Here, we found that histone deacetylase 5 (HDAC5) associates with KLF2 and represses KLF2 transcriptional activation. HDAC5 resided with KLF2 in the nuclei of human umbilical cord vein endothelial cells (HUVECs). Steady laminar flow attenuated the association of HDAC5 with KLF2 via stimulating HDAC5 phosphorylation-dependent nuclear export in HUVEC. We also mapped the KLF2-HDAC5-interacting domains and found that the N-terminal region of HDAC5 interacts with the C-terminal domain of KLF2. Chromatin immunoprecipitation and luciferase reporter assays showed that HDAC5 through a direct association with KLF2 suppressed KLF2 transcriptional activation. HDAC5 overexpression inhibited KLF2-dependent endothelial nitric oxide synthesis (eNOS) promoter activity in COS7 cell and gene expression in both HUVECs and bovine aortic endothelial cells (BAECs). Conversely, HDAC5 silencing enhanced KLF2 transcription and hence eNOS expression in HUVEC. Moreover, we observed that the level of eNOS protein in the thoracic aorta isolated from HDAC5 knockout mice was higher, whereas expression of pro-inflammatory vascular cell adhesion molecule 1 was lower, compared with those of HDAC5 wild-type mice. CONCLUSIONS We reveal a novel role of HDAC5 in modulating the KLF2 transcriptional activation and eNOS expression. These findings suggest that HDAC5, a binding partner and modulator of KLF2, could be a new therapeutic target to prevent vascular endothelial dysfunction associated with cardiovascular diseases.

Resistin, a recently discovered proinflammatory cytokine, has been variably associated with insulin resistance, inflammation, and renal dysfunction. We investigated the association of plasma resistin with estimated glomerular filtration rate and albuminuria in 1575 hypertensive adults without known coronary heart disease or stroke (857 blacks and 718 non-Hispanic whites). Resistin was measured by a solid phase sandwich immunoassay, estimated glomerular filtration rate was estimated from serum creatinine, and albuminuria was expressed as urine albumin:creatinine ratio. After adjustment for coronary heart disease risk factors (age, sex, body mass index, smoking history, systolic blood pressure, diabetes, and total and high-density lipoprotein cholesterol) and use of renin-angiotensin blockers and statins, higher plasma resistin levels were associated with lower estimated glomerular filtration rate in both ethnic groups (each P<0.0001); the association remained significant after further adjustment for a marker of insulin resistance (homeostasis model assessment for insulin resistance) and a marker of inflammation (plasma C-reactive protein) and was seen in subjects with and without diabetes (each P<0.0001) in both ethnic groups. Higher plasma resistin levels were associated with a higher urine albumin:creatinine ratio in black subjects with diabetes (P<0.0001) and non-Hispanic white subjects with diabetes (P=0.032), independent of coronary heart disease risk factors, hypertension medication use, and statin use; the association remained significant after additional adjustment for homeostasis model assessment for insulin resistance and C-reactive protein. In adults with hypertension, higher circulating resistin levels were associated with a lower estimated glomerular filtration rate and with increased urine albumin:creatinine ratio in the presence of concomitant diabetes. This association was independent of coronary heart disease risk factors and markers of insulin resistance and inflammation.