ABSTRACT
We present the software Condition-specific Regulatory Units Prediction (CRUP) to infer from epigenetic marks a list of regulatory units consisting of dynamically changing enhancers with their target genes. The workflow consists of a novel pre-trained enhancer predictor that can be reliably applied across cell types and species, solely based on histone modification ChIP-seq data. Enhancers are subsequently assigned to different conditions and correlated with gene expression to derive regulatory units. We thoroughly test and then apply CRUP to a rheumatoid arthritis model, identifying enhancer-gene pairs comprising known disease genes as well as new candidate genes.
Subject(s)
Enhancer Elements, Genetic , Software , Animals , Arthritis, Experimental/genetics , Arthritis, Rheumatoid/genetics , Chromatin Immunoprecipitation Sequencing , Histone Code , MiceABSTRACT
Breast cancer is one of the most common cancers in humans and will on average affect up to one in eight women in their lifetime in the United States and Europe. The Women's Health Initiative and the Million Women Study have shown that hormone replacement therapy is associated with an increased risk of incident and fatal breast cancer. In particular, synthetic progesterone derivatives (progestins) such as medroxyprogesterone acetate (MPA), used in millions of women for hormone replacement therapy and contraceptives, markedly increase the risk of developing breast cancer. Here we show that the in vivo administration of MPA triggers massive induction of the key osteoclast differentiation factor RANKL (receptor activator of NF-κB ligand) in mammary-gland epithelial cells. Genetic inactivation of the RANKL receptor RANK in mammary-gland epithelial cells prevents MPA-induced epithelial proliferation, impairs expansion of the CD49f(hi) stem-cell-enriched population, and sensitizes these cells to DNA-damage-induced cell death. Deletion of RANK from the mammary epithelium results in a markedly decreased incidence and delayed onset of MPA-driven mammary cancer. These data show that the RANKL/RANK system controls the incidence and onset of progestin-driven breast cancer.
Subject(s)
Mammary Neoplasms, Experimental/chemically induced , Mammary Neoplasms, Experimental/pathology , Progestins/adverse effects , RANK Ligand/metabolism , Animals , Apoptosis/radiation effects , Cell Differentiation , Cell Proliferation/drug effects , DNA Damage , Epithelial Cells/cytology , Epithelial Cells/drug effects , Epithelial Cells/metabolism , Epithelial Cells/radiation effects , Female , Gamma Rays , Integrin alpha6/metabolism , Mammary Neoplasms, Experimental/genetics , Mammary Neoplasms, Experimental/metabolism , Medroxyprogesterone Acetate/administration & dosage , Medroxyprogesterone Acetate/adverse effects , Mice , NF-kappa B/metabolism , Osteoclasts/cytology , Phosphoproteins/analysis , Phosphoproteins/immunology , Progestins/administration & dosage , RANK Ligand/deficiency , RANK Ligand/genetics , Receptor Activator of Nuclear Factor-kappa B/deficiency , Receptor Activator of Nuclear Factor-kappa B/genetics , Receptor Activator of Nuclear Factor-kappa B/metabolism , Signal Transduction , Stem Cells/cytology , Stem Cells/drug effects , Stem Cells/metabolismABSTRACT
Activation of the innate immune system in obesity is a risk factor for the development of type 2 diabetes. The aim of the current study was to investigate the notion that increased numbers of macrophages exist in the islets of type 2 diabetes patients and that this may be explained by a dysregulation of islet-derived inflammatory factors. Increased islet-associated immune cells were observed in human type 2 diabetic patients, high-fat-fed C57BL/6J mice, the GK rat, and the db/db mouse. When cultured islets were exposed to a type 2 diabetic milieu or when islets were isolated from high-fat-fed mice, increased islet-derived inflammatory factors were produced and released, including interleukin (IL)-6, IL-8, chemokine KC, granulocyte colony-stimulating factor, and macrophage inflammatory protein 1alpha. The specificity of this response was investigated by direct comparison to nonislet pancreatic tissue and beta-cell lines and was not mimicked by the induction of islet cell death. Further, this inflammatory response was found to be biologically functional, as conditioned medium from human islets exposed to a type 2 diabetic milieu could induce increased migration of monocytes and neutrophils. This migration was blocked by IL-8 neutralization, and IL-8 was localized to the human pancreatic alpha-cell. Therefore, islet-derived inflammatory factors are regulated by a type 2 diabetic milieu and may contribute to the macrophage infiltration of pancreatic islets that we observe in type 2 diabetes.
Subject(s)
Diabetes Mellitus, Type 2/pathology , Islets of Langerhans/pathology , Macrophages/pathology , Aged , Aged, 80 and over , Antigens, CD/analysis , Cell Count , Female , HLA-B Antigens/analysis , Humans , Islets of Langerhans/immunology , Macrophages/immunology , Male , Middle Aged , Neoplasms/pathology , Neoplasms/surgeryABSTRACT
Upon release into circulation, the potent insulin secretagogues glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are rapidly cleaved and inactivated by the enzyme dipeptidyl peptidase IV (DP IV). Long-term administration of specific DP IV inhibitors, so as to enhance circulating active GIP and GLP-1 levels, has been shown to improve glucose tolerance and beta-cell glucose responsiveness and to reduce hyperinsulinemia in the Vancouver diabetic fatty (VDF) rat model of type 2 diabetes. Using the VDF model, the current study was undertaken to examine the effects of long-term DP IV inhibitor treatment on insulin sensitivity. Euglycemic-hyperinsulinemic clamps were performed on two sets of conscious VDF rats treated with or without the DP IV inhibitor P32/98 (20 mg. kg(-1). day(-1) for 12 weeks). The protocol consisted of three sequential 90-min periods with insulin infusion rates of 0, 5, and 15 mU. kg(-1). min(-1) and included a constant infusion of [ (3)H]glucose for measure of hepatic and peripheral insulin sensitivity. Relative to untreated littermates, the treated animals showed a left shift in the sensitivity of hepatic glucose output to insulin (average reduction approximately 6 micro mol. kg(-1). min(-1)) and a marked gain in peripheral responsiveness to insulin, with glucose disposal rates increasing 105 and 216% in response to the two insulin steps (versus 2 and 46% in controls). These results provide the first demonstration of improved hepatic and peripheral insulin sensitivity after DP IV inhibitor therapy, and coupled with apparent improvements in beta-cell function, they offer strong support for the utility of these compounds in the treatment of diabetes.