Decreased IL7Rα and TdT expression underlie the skewed immunoglobulin repertoire of human B-cell precursors from fetal origin

Newborns are unable to mount antibody responses towards certain antigens. This has been related to the restricted repertoire of immunoglobulin (Ig) genes of their B cells. The mechanisms underlying the restricted fetal Ig gene repertoire are currently unresolved. We here addressed this with detailed molecular and cellular analysis of human precursor-B cells from fetal liver, fetal bone marrow (BM), and pediatric BM. In the absence of selection processes, fetal B-cell progenitors more frequently used proximal V, D and J genes in complete IGH gene rearrangements, despite normal Ig locus contraction. Fewer N-nucleotides were added in IGH gene rearrangements in the context of low TdT and XRCC4 expression. Moreover, fetal progenitor-B cells expressed lower levels of IL7Rα than their pediatric counterparts. Analysis of progenitor-B cells from IL7Rα-deficient patients revealed that TdT expression and N-nucleotides additions in Dh-Jh junctions were dependent on functional IL7Rα. Thus, IL7Rα affects TdT expression, and decreased expression of this receptor underlies at least in part the skewed Ig repertoire formation in fetal B-cell precursors. These new insights provide a better understanding of the formation of adaptive immunity in the developing fetus

Identification of a novel locus on chromosome 2q13, which predisposes to clinical vertebral fractures independently of bone density

OBJECTIVES: To identify genetic determinants of susceptibility to clinical vertebral fractures, which is an important complication of osteoporosis. METHODS: Here we conduct a genome-wide association study in 1553 postmenopausal women with clinical vertebral fractures and 4340 controls, with a two-stage replication involving 1028 cases and 3762 controls. Potentially causal variants were identified using expression quantitative trait loci (eQTL) data from transiliac bone biopsies and bioinformatic studies. RESULTS: A locus tagged by rs10190845 was identified on chromosome 2q13, which was significantly associated with clinical vertebral fracture (P=1.04×10-9) with a large effect size (OR 1.74, 95% CI 1.06 to 2.6). Bioinformatic analysis of this locus identified several potentially functional SNPs that are associated with expression of the positional candidate genes TTL (tubulin tyrosine ligase) and SLC20A1 (solute carrier family 20 member 1). Three other suggestive loci were identified on chromosomes 1p31, 11q12 and 15q11. All these loci were novel and had not previously been associated with bone mineral density or clinical fractures. CONCLUSION: We have identified a novel genetic variant that is associated with clinical vertebral fractures by mechanisms that are independent of BMD. Further studies are now in progress to validate this association and evaluate the underlying mechanism.Funding: ORCADES was supported by the Chief Scientist Office of the Scottish Government (CZB/4/276, CZB/4/710), the Royal Society, the MRC Human Genetics Unit, Arthritis Research UK and the European Union framework programme 6 EUROSPAN project (contract no. LSHG-CT-2006-018947). DNA extractions were performed at the Wellcome Trust Clinical Research Facility in Edinburgh. We would like to acknowledge the invaluable contributions of Lorraine Anderson and the research nurses in Orkney, the administrative team in Edinburgh and the people of Orkney. CABRIO was supported by the Instituto de Salud Carlos III and Fondos FEDER from the EU (PI 11/1092 and PI12/615). The AOGC study was funded by the Australian National Health and Medical Research Council (Project grant 511132). Lothian Birth Cohort 1921 phenotype collection was supported by the UK’s Biotechnology and Biological Sciences Research Council (BBSRC), The Royal Society and The Chief Scientist Office of the Scottish Government. Phenotype collection in the Lothian Birth Cohort 1936 was supported by Age UK (The Disconnected Mind project). Genotyping of the cohorts was funded by the BBSRC. The work was undertaken by the University of Edinburgh Centre for Cognitive Ageing and Cognitive Epidemiology, part of the cross council Lifelong Health and Wellbeing Initiative (MR/K026992/1). Funding from the BBSRC and Medical Research Council (MRC) is gratefully acknowledged. Research work on Slovenian case and control samples was funded by Slovenian Research Agency (project no. P3-0298 and J3-2330). The Danish National Birth Cohort (DNBC) is a result of major grants from the Danish National Research Foundation, the Danish Pharmacists’Fund, the Egmont Foundation, the March of Dimes Birth Defects Foundation, the Augustinus Foundation and the Health Fund of the Danish Health Insurance Societies. The DNBC biobank is a part of the Danish National Biobank resource, which is supported by the Novo Nordisk Foundation. Dr Bjarke Feenstra is supported by an Oak Foundation Fellowship. The Framingham Study was funded by grants from the US National Institute for Arthritis, Musculoskeletal and Skin Diseases and National Institute on Aging (R01 AR 41398 and R01 AR061162; DPK and R01 AR 050066; DK). The Framingham Heart Study of the National Heart, Lung, and Blood Institute of the National Institutes of Health and Boston University School of Medicine were supported by the National Heart, Lung, and Blood Institute’s Framingham Heart Study (N01-HC-25195) and its contract with Affymetrix, Inc. for genotyping services (N02-HL-6-4278). Analyses reflect intellectual input and resource development from the Framingham Heart Study investigators participating in the SNP Health Association Resource (SHARe) project. A portion of this research was conducted using the Linux Cluster for Genetic Analysis (LinGA-II) funded by the Robert Dawson Evans Endowment of the Department of Medicine at Boston University School of Medicine and Boston Medical Center. This research was performed within the Genetic Factors for Osteoporosis (GEFOS) consortium, funded by the European Commission (HEALTH-F2-2008-201865-GEFOS).Acknowledgments: The authors are grateful to the patients and controls from the different centres who agreed to participate in this study. We would like to thank Ms Dilruba Kabir at the Rheumatology and Bone Disease Unit, CGEM-IGMM, Edinburgh, UK; Mr Matt Sims at the MRC Epidemiology Unit, University of Cambridge, UK; Ms Mila Jhamai and Ms Sarah Higgins at the Genetics Laboratory of Erasmus MC, Rotterdam, The Netherlands; Ms Johanna Hadler, Ms Kathryn A Addison and Ms Karena Pryce of the University of Queensland Centre for Clinical Genomics, Brisbane, Australia, for technical support on the genotyping stage; and Mr Marijn Verkerk and Dr Anis Abuseiris at the Genetics Laboratory of Erasmus MC, Rotterdam, for assistance on the data analysis. We would like to acknowledge the invaluable contributions of Lorraine Anderson and the research nurses in Orkney, the administrative team in Edinburgh and the people of Orkney. We would also like to thank Professor Nick Gilbert and Dr Giovanny Rodriguez-Blanco for their comments and advice on the manuscript preparation. This study makes use of data generated by the Wellcome Trust Case Control Consortium. A full list of the investigators who contributed to the generation of the data is available at www.wtccc.org.uk

Neil3-dependent base excision repair regulates lipid metabolism and prevents atherosclerosis in Apoe-deficient mice

Increasing evidence suggests that oxidative DNA damage accumulates in atherosclerosis. Recently, we showed that a genetic variant in the human DNA repair enzyme NEIL3 was associated with increased risk of myocardial infarction. Here, we explored the role of Neil3/NEIL3 in atherogenesis by both clinical and experimental approaches. Human carotid plaques revealed increased NEIL3 mRNA expression which significantly correlated with mRNA levels of the macrophage marker CD68. Apoe−/−Neil3−/− mice on high-fat diet showed accelerated plaque formation as compared to Apoe−/− mice, reflecting an atherogenic lipid profile, increased hepatic triglyceride levels and attenuated macrophage cholesterol efflux capacity. Apoe−/−Neil3−/− mice showed marked alterations in several pathways affecting hepatic lipid metabolism, but no genotypic alterations in genome integrity or genome-wide accumulation of oxidative DNA damage. These results suggest a novel role for the DNA glycosylase Neil3 in atherogenesis in balancing lipid metabolism and macrophage function, potentially independently of genome-wide canonical base excision repair of oxidative DNA damage

Skeletal Site-Related Variation in Human Trabecular Bone Transcriptome and Signaling

BACKGROUND: The skeletal site-specific influence of multiple genes on bone morphology is recognised, but the question as to how these influences may be exerted at the molecular and cellular level has not been explored. METHODOLOGY: To address this question, we have compared global gene expression profiles of human trabecular bone from two different skeletal sites that experience vastly different degrees of mechanical loading, namely biopsies from iliac crest and lumbar spinal lamina. PRINCIPAL FINDINGS: In the lumbar spine, compared to the iliac crest, the majority of the differentially expressed genes showed significantly increased levels of expression; 3406 transcripts were up- whilst 838 were down-regulated. Interestingly, all gene transcripts that have been recently demonstrated to be markers of osteocyte, as well as osteoblast and osteoclast-related genes, were markedly up-regulated in the spine. The transcriptome data is consistent with osteocyte numbers being almost identical at the two anatomical sites, but suggesting a relatively low osteocyte functional activity in the iliac crest. Similarly, osteoblast and osteoclast expression data suggested similar numbers of the cells, but presented with higher activity in the spine than iliac crest. This analysis has also led to the identification of expression of a number of transcripts, previously known and novel, which to our knowledge have never earlier been associated with bone growth and remodelling. CONCLUSIONS AND SIGNIFICANCE: This study provides molecular evidence explaining anatomical and micro-architectural site-related changes in bone cell function, which is predominantly attributable to alteration in cell transcriptional activity. A number of novel signaling molecules in critical pathways, which have been hitherto not known to be expressed in bone cells of mature vertebrates, were identified

Identification of a novel locus on chromosome 2q13, which predisposes to clinical vertebral fractures independently of bone density.

OBJECTIVES: To identify genetic determinants of susceptibility to clinical vertebral fractures, which is an important complication of osteoporosis. METHODS: Here we conduct a genome-wide association study in 1553 postmenopausal women with clinical vertebral fractures and 4340 controls, with a two-stage replication involving 1028 cases and 3762 controls. Potentially causal variants were identified using expression quantitative trait loci (eQTL) data from transiliac bone biopsies and bioinformatic studies. RESULTS: A locus tagged by rs10190845 was identified on chromosome 2q13, which was significantly associated with clinical vertebral fracture (P=1.04×10-9) with a large effect size (OR 1.74, 95% CI 1.06 to 2.6). Bioinformatic analysis of this locus identified several potentially functional SNPs that are associated with expression of the positional candidate genes TTL (tubulin tyrosine ligase) and SLC20A1 (solute carrier family 20 member 1). Three other suggestive loci were identified on chromosomes 1p31, 11q12 and 15q11. All these loci were novel and had not previously been associated with bone mineral density or clinical fractures. CONCLUSION: We have identified a novel genetic variant that is associated with clinical vertebral fractures by mechanisms that are independent of BMD. Further studies are now in progress to validate this association and evaluate the underlying mechanism

Meta-analysis of genome-wide scans for total body BMD in children and adults reveals allelic heterogeneity and age-specific effects at the WNT16 locus

To identify genetic loci influencing bone accrual, we performed a genome-wide association scan for total-body bone mineral density (TB-BMD) variation in 2,660 children of different ethnicities. We discovered variants in 7q31.31 associated with BMD measurements, with the lowest P = 4.1×10-11 observed for rs917727 with minor allele frequency of 0.37. We sought replication for all SNPs located ±500 kb from rs917727 in 11,052 additional individuals from five independent studies including children and adults, together with de novo genotyping of rs3801387 (in perfect linkage disequilibrium (LD) with rs917727) in 1,014 mothers of children from the discovery cohort. The top signal mapping in the surroundings of WNT16 was replicated across studies with a meta-analysis P = 2.6×10-31 and an effect size explaining between 0.6%-1.8% of TB-BMD variance. Conditional analyses on this signal revealed a secondary signal for total body BMD (P = 1.42×10-10) for rs4609139 and mapping to C7orf58. We a

Comparison of upstream regulators in human ex vivo cultured cornea limbal epithelial stem cells and differentiated corneal epithelial cells

Background The surface of the human eye is covered by corneal epithelial cells (CECs) which regenerate from a small population of limbal epithelial stem cells (LESCs). Cell therapy with LESCs is a non-penetrating treatment for preventing blindness due to LESC deficiency or dysfunction. Our aim was to identify new putative molecular markers and upstream regulators in the LESCs and associated molecular pathways. Results Genome-wide microarray transcriptional profiling was used to compare LESCs to differentiated human CECs. Ingenuity-based pathway analysis was applied to identify upstream regulators and pathways specific to LESCs. ELISA and flow cytometry were used to measure secreted and surface expressed proteins, respectively. More than 2 fold increase and decrease in expression could be found in 1830 genes between the two cell types. A number of molecules functioning in cellular movement (381), proliferation (567), development (552), death and survival (520), and cell-to-cell signaling (290) were detected having top biological functions in LESCs and several of these were confirmed by flow cytometric surface protein analysis. Custom-selected gene groups related to stemness, differentiation, cell adhesion, cytokines and growth factors as well as angiogenesis could be analyzed. The results show that LESCs play a key role not only in epithelial differentiation and tissue repair, but also in controlling angiogenesis and extracellular matrix integrity. Some pro-inflammatory cytokines were found to be important in stemness-, differentiation- and angiogenesis-related biological functions: IL-6 and IL-8 participated in most of these biological pathways as validated by their secretion from LESC cultures. Conclusions The gene and molecular pathways may provide a more specific understanding of the signaling molecules associated with LESCs, therefore, help better identify and use these cells in the treatment of ocular surface diseases

The human ortholog of the rodent testis-specific ABC transporter Abca17 is a ubiquitously expressed pseudogene (ABCA17P) and shares a common 5' end with ABCA3

Background During the past years, we and others discovered a series of human ATP-binding cassette (ABC) transporters, now referred to as ABC A-subfamily transporters. Recently, a novel testis-specific ABC A transporter, Abca17, has been cloned in rodent. In this study, we report the identification and characterization of the human ortholog of rodent Abca17. Results The novel human ABC A-transporter gene on chromosome 16p13.3 is ubiquitously expressed with highest expression in glandular tissues and the heart. The new ABC transporter gene exhibits striking nucleotide sequence homology with the recently cloned mouse (58%) and rat Abca17 (51%), respectively, and is located in the syntenic region of mouse Abca17 indicating that it represents the human ortholog of rodent Abca17. However, unlike in the mouse, the full-length ABCA17 transcript (4.3 kb) contains numerous mutations that preclude its translation into a bona fide ABC transporter protein strongly suggesting that the human ABCA17 gene is a transcribed pseudogene (ABCA17P). We identified numerous alternative ABCA17P splice variants which are transcribed from two distinct transcription initiation sites. Genomic analysis revealed that ABCA17P borders on another ABC A-subfamily transporter – the lung surfactant deficiency gene ABCA3. Surprisingly, we found that both genes overlap at their first exons and are transcribed from opposite strands. This genomic colocalization and the observation that the ABCA17P and ABCA3 genes share significant homologies in several exons (up to 98%) suggest that both genes have evolved by gene duplication. Conclusion Our results demonstrate that ABCA17P and ABCA3 form a complex of overlapping genes in the human genome from which both non-coding and protein-coding ABC A-transporter RNAs are expressed. The fact that both genes overlap at their 5' ends suggests interdependencies in their regulation and may have important implications for the functional analysis of the disease gene ABCA3. Moreover, this is the first demonstration of the expression of a pseudogene and its parent gene from a common overlapping DNA region in the human genome

Global miRNA expression analysis of serous and clear cell ovarian carcinomas identifies differentially expressed miRNAs including miR-200c-3p as a prognostic marker

Background Improved insight into the molecular characteristics of the different ovarian cancer subgroups is needed for developing a more individualized and optimized treatment regimen. The aim of this study was to a) identify differentially expressed miRNAs in high-grade serous ovarian carcinoma (HGSC), clear cell ovarian carcinoma (CCC) and ovarian surface epithelium (OSE), b) evaluate selected miRNAs for association with clinical parameters including survival and c) map miRNA-mRNA interactions. Methods Differences in miRNA expression between HGSC, CCC and OSE were analyzed by global miRNA expression profiling (Affymetrix GeneChip miRNA 2.0 Arrays, n = 12, 9 and 9, respectively), validated by RT-qPCR (n = 35, 19 and 9, respectively), and evaluated for associations with clinical parameters. For HGSC, differentially expressed miRNAs were linked to differentially expressed mRNAs identified previously. Results Differentially expressed miRNAs (n = 78) between HGSC, CCC and OSE were identified (FDR < 0.01%), of which 18 were validated (p < 0.01) using RT-qPCR in an extended cohort. Compared with OSE, miR-205-5p was the most overexpressed miRNA in HGSC. miR-200 family members and miR-182-5p were the most overexpressed in HGSC and CCC compared with OSE, whereas miR-383 was the most underexpressed. miR-205-5p and miR-200 members target epithelial-mesenchymal transition (EMT) regulators, apparently being important in tumor progression. miR-509-3-5p, miR-509-5p, miR-509-3p and miR-510 were among the strongest differentiators between HGSC and CCC, all being significantly overexpressed in CCC compared with HGSC. High miR-200c-3p expression was associated with poor progression-free (p = 0.031) and overall (p = 0.026) survival in HGSC patients. Interacting miRNA and mRNA targets, including those of a TP53-related pathway presented previously, were identified in HGSC. Conclusions Several miRNAs differentially expressed between HGSC, CCC and OSE have been identified, suggesting a carcinogenetic role for these miRNAs. miR-200 family members, targeting EMT drivers, were mostly overexpressed in both subgroups, among which miR-200c-3p was associated with survival in HGSC patients. A set of miRNAs differentiates CCC from HGSC, of which miR-509-3-5p and miR-509-5p are the strongest classifiers. Several interactions between miRNAs and mRNAs in HGSC were mapped

Vitamin D metabolites influence expression of genes concerning cellular viability and function in insulin producing β-cells (INS1E)

Background Studies have shown that vitamin D can enhance glucose-stimulated insulin secretion (GSIS) and change the expression of genes in pancreatic β-cells. Still the mechanisms linking vitamin D and GSIS are unknown. Material and methods We used an established β-cell line, INS1E. INS1E cells were pre-treated with 10 nM 1,25(OH)2vitamin D or 10 nM 25(OH)vitamin D for 72 h and stimulated with 22 mM glucose for 60 min. RNA was extracted for gene expression analysis. Results Expression of genes affecting viability, apoptosis and GSIS changed after pre-treatment with both 1,25(OH)2vitamin D and 25(OH)vitamin D in INS1E cells. Stimulation with glucose after pre-treatment of INS1E cells with 1,25(OH)2vitamin D resulted in 181 differentially expressed genes, whereas 526 genes were differentially expressed after pre-treatment with 25(OH)vitamin D. Conclusion Vitamin D metabolites may affect pancreatic β-cells and GSIS through changed gene expression for genes involved in β-cell function and viability