Nuclear receptors in vascular biology

Nuclear receptors sense a wide range of steroids and hormones (estrogens, progesterone, androgens, glucocorticoid, and mineralocorticoid), vitamins (A and D), lipid metabolites, carbohydrates, and xenobiotics. In response to these diverse but critically important mediators, nuclear receptors regulate the homeostatic control of lipids, carbohydrate, cholesterol, and xenobiotic drug metabolism, inflammation, cell differentiation and development, including vascular development. The nuclear receptor family is one of the most important groups of signaling molecules in the body and as such represent some of the most important established and emerging clinical and therapeutic targets. This review will highlight some of the recent trends in nuclear receptor biology related to vascular biology

Perivascular Fat and the Microcirculation: Relevance to Insulin Resistance, Diabetes, and Cardiovascular Disease

Type 2 diabetes and its major risk factor, obesity, are a growing burden for public health. The mechanisms that connect obesity and its related disorders, such as insulin resistance, type 2 diabetes, and hypertension, are still undefined. Microvascular dysfunction may be a pathophysiologic link between insulin resistance and hypertension in obesity. Many studies have shown that adipose tissue-derived substances (adipokines) interact with (micro)vascular function and influence insulin sensitivity. In the past, research focused on adipokines from perivascular adipose tissue (PVAT). In this review, we focus on the interactions between adipokines, predominantly from PVAT, and microvascular function in relation to the development of insulin resistance, diabetes, and cardiovascular disease

Therapeutic Surgical Management of Palpable Melanoma Groin Metastases: Superficial or Combined Superficial and Deep Groin Lymph Node Dissection

Item does not contain fulltextBACKGROUND: Management of patients with clinically detectable lymph node metastasis to the groin is by ilioinguinal or combined superficial and deep groin dissection (CGD) according to most literature, but in practice superficial groin dissection (SGD) only is still performed in some centers. The aim of this study is to evaluate the experience in CGD versus SGD patients in our center. METHODS: Between 1991 and 2009, 121 therapeutic CGD and 48 SGD were performed in 169 melanoma patients with palpable groin metastases at our institute. Median follow-up was 20 and, for survivors, 45 months. RESULTS: In this heterogeneous group of patients, overall (OS) and disease-free survival, local control rates, and morbidity rates were not significantly different between CGD and SGD patients. However, CGD patients had a trend towards more chronic lymphedema. Superficial lymph node ratio, the number of positive superficial lymph nodes, and the presence of deep nodes were prognostic factors for survival. CGD patients with involved deep lymph nodes (24.8%) had estimated 5-year OS of 12% compared with 40% with no involved deep lymph nodes (p = 0.001). Preoperative computed tomography (CT) scan had high negative predictive value of 91% for detection of pelvic nodal involvement. CONCLUSIONS: This study demonstrated that survival and local control do not differ for patients with palpable groin metastases treated by CGD or SGD. Patients without pathological iliac nodes on CT might safely undergo SGD, while CGD might be reserved for patients with multiple positive nodes on SGD and/or positive deep nodes on CT scan

Somatic Mutation Profiles of MSI and MSS Colorectal Cancer Identified by Whole Exome Next Generation Sequencing and Bioinformatics Analysis

BACKGROUND: Colorectal cancer (CRC) is with approximately 1 million cases the third most common cancer worldwide. Extensive research is ongoing to decipher the underlying genetic patterns with the hope to improve early cancer diagnosis and treatment. In this direction, the recent progress in next generation sequencing technologies has revolutionized the field of cancer genomics. However, one caveat of these studies remains the large amount of genetic variations identified and their interpretation. METHODOLOGY/PRINCIPAL FINDINGS: Here we present the first work on whole exome NGS of primary colon cancers. We performed 454 whole exome pyrosequencing of tumor as well as adjacent not affected normal colonic tissue from microsatellite stable (MSS) and microsatellite instable (MSI) colon cancer patients and identified more than 50,000 small nucleotide variations for each tissue. According to predictions based on MSS and MSI pathomechanisms we identified eight times more somatic non-synonymous variations in MSI cancers than in MSS and we were able to reproduce the result in four additional CRCs. Our bioinformatics filtering approach narrowed down the rate of most significant mutations to 359 for MSI and 45 for MSS CRCs with predicted altered protein functions. In both CRCs, MSI and MSS, we found somatic mutations in the intracellular kinase domain of bone morphogenetic protein receptor 1A, BMPR1A, a gene where so far germline mutations are associated with juvenile polyposis syndrome, and show that the mutations functionally impair the protein function. CONCLUSIONS/SIGNIFICANCE: We conclude that with deep sequencing of tumor exomes one may be able to predict the microsatellite status of CRC and in addition identify potentially clinically relevant mutations

The Nutritional Induction of COUP-TFII Gene Expression in Ventromedial Hypothalamic Neurons Is Mediated by the Melanocortin Pathway

BACKGROUND: The nuclear receptor chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) is an important coordinator of glucose homeostasis. We report, for the first time, a unique differential regulation of its expression by the nutritional status in the mouse hypothalamus compared to peripheral tissues. METHODOLOGY/PRINCIPAL FINDINGS: Using hyperinsulinemic-euglycemic clamps and insulinopenic mice, we show that insulin upregulates its expression in the hypothalamus. Immunofluorescence studies demonstrate that COUP-TFII gene expression is restricted to a subpopulation of ventromedial hypothalamic neurons expressing the melanocortin receptor. In GT1-7 hypothalamic cells, the MC4-R agonist MTII leads to a dose dependant increase of COUP-TFII gene expression secondarily to a local increase in cAMP concentrations. Transfection experiments, using a COUP-TFII promoter containing a functional cAMP responsive element, suggest a direct transcriptional activation by cAMP. Finally, we show that the fed state or intracerebroventricular injections of MTII in mice induce an increased hypothalamic COUP-TFII expression associated with a decreased hepatic and pancreatic COUP-TFII expression. CONCLUSIONS/SIGNIFICANCE: These observations strongly suggest that hypothalamic COUP-TFII gene expression could be a central integrator of insulin and melanocortin signaling pathway within the ventromedial hypothalamus. COUP-TFII could play a crucial role in brain integration of circulating signal of hunger and satiety involved in energy balance regulation

Essential Role of Chromatin Remodeling Protein Bptf in Early Mouse Embryos and Embryonic Stem Cells

We have characterized the biological functions of the chromatin remodeling protein Bptf (Bromodomain PHD-finger Transcription Factor), the largest subunit of NURF (Nucleosome Remodeling Factor) in a mammal. Bptf mutants manifest growth defects at the post-implantation stage and are reabsorbed by E8.5. Histological analyses of lineage markers show that Bptf−/− embryos implant but fail to establish a functional distal visceral endoderm. Microarray analysis at early stages of differentiation has identified Bptf-dependent gene targets including homeobox transcriptions factors and genes essential for the development of ectoderm, mesoderm, and both definitive and visceral endoderm. Differentiation of Bptf−/− embryonic stem cell lines into embryoid bodies revealed its requirement for development of mesoderm, endoderm, and ectoderm tissue lineages, and uncovered many genes whose activation or repression are Bptf-dependent. We also provide functional and physical links between the Bptf-containing NURF complex and the Smad transcription factors. These results suggest that Bptf may co-regulate some gene targets of this pathway, which is essential for establishment of the visceral endoderm. We conclude that Bptf likely regulates genes and signaling pathways essential for the development of key tissues of the early mouse embryo

Health Care Expenditures Attributable to Smoking in Military Veterans

INTRODUCTION: The health effects of cigarette smoking have been estimated to account for between 6%–8% of U.S. health care expenditures. We estimated Veterans Health Administration (VHA) health care costs attributable to cigarette smoking. METHODS: VHA survey and administrative data provided the number of Veteran enrollees, current and former smoking prevalence, and the cost of 4 types of care for groups defined by age, gender, and region. Cost and smoking status could not be linked at the enrollee level, so we used smoking attributable fractions estimated in sample of U.S. residents where the linkage could be made. RESULTS: The 7.7 million Veterans enrolled in VHA received $40.2 billion in VHA provided health services in 2010. We estimated that$2.7 billion in VHA costs were attributable to the health effects of smoking. This was 7.6% of the $35.3 billion spent on the types of care for which smoking-attributable fractions could be determined. The fraction of inpatient costs that was attributable to smoking (11.4$1.7 billion) than to former smokers ($983 million). CONCLUSIONS: The fraction of VHA costs attributable to smoking is similar to that of other health care systems. Smoking among Veterans is slowly decreasing, but prevalence remains high in Veterans with psychiatric and substance use disorders, and in younger and female Veterans. VHA has adopted a number of smoking cessation programs that have the potential for reducing future smoking-attributable costs

Mouse lacking COUP-TFII as an animal model of Bochdalek-type congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH), a life-threatening anomaly, is a major cause of pediatric mortality. Although the disease was described >350 years ago, the etiology of CDH is poorly understood. Here, we show that tissue-specific null mutants of COUP-TFII exhibit Bochdalek-type CDH, the most common form of CDH. COUP-TFII, a member of orphan nuclear receptors, is expressed in regions critical for the formation of the diaphragm during embryonic development. Ablation of COUP-TFII in the foregut mesenchyme, including the posthepatic mesenchymal plate (PHMP), results in the malformation of the diaphragm and the failure of appropriate attachment of the PHMP to the body wall. Thus, both the stomach and liver enter the thoracic cavity, leading to lung hypoplasia and neonatal death. Recently a minimally deleted region for CDH has been identified on chromosome 15q26.1-26.2 by CGH array and FISH analysis. COUP-TFII is one of the four known genes residing within this critical region. Our finding suggests that COUP-TFII is a likely contributor to the formation of CDH in individuals with 15q deletions, and it may also be a potential contributor to some other Bochdalek-type of CDH