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Expression of sFlt1 and its function in the glomerular endothelium

sFlt1在肾小球内皮细胞中的表达及其功能

基本信息

批准号：
8730136
负责人：
CHRISTIE P. THOMAS
金额：
$ 31.02万
依托单位：
UNIVERSITY OF IOWA
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-09-30 至 2016-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8730136
关键词：
5&apos Flanking Region Actins Angiogenesis Inhibitors Angiotensin II Antibodies Attention Beryllium Binding Biogenesis Cell physiology Cells Chemotherapy-Oncologic Procedure DNA Sequence Rearrangement Development Ectopic Expression Elements Endothelial Cells Endothelin-1 Exons FLT1 gene Genes Genetic Transcription Goals Hour Hypertension Hypoxia Introns Kidney Kidney Diseases Lead Lesion Mediating Membrane Messenger RNA Modeling Monoclonal Antibodies Mus Nitric Oxide Outcome Pathway interactions Patients Placenta Plasma Polyadenylation Post-Transcriptional Regulation Pre-Eclampsia Preproendothelin Process Protein Isoforms Proteins Proteinuria Public Health RNA Splicing Rattus Receptor Activation Receptor, Angiotensin, Type 1 Recombinants Regulation Regulator Genes Relative (related person)Renal glomerular disease Research Proposals Risk Factors Role Septic Toxemia Serum Signal Pathway Signal Transduction Syncytiotrophoblast Syndrome Testing Transcript Transcriptional Regulation Tyrosine Kinase Inhibitor Undifferentiated Vascular Endothelial Growth Factor Receptor Vascular Endothelial Growth Factor Receptor-1 Vascular Endothelial Growth Factors Woman cell injury chemotherapy cytotrophoblast glomerular endothelium human NOS3 protein hypertension control hypertension treatment injured intercellular communication mRNA Expression mRNA Stability modifiable risk nephrin new therapeutic target novel podocyte pregnant promoter receptor trophoblast

项目摘要

DESCRIPTION (provided by applicant): Infusing an anti-VEGF antibody or a soluble VEGF receptor antagonist, sFlt1, in rats and mice lead to the development of severe proteinuria and hypertension accompanied by glomerular endotheliosis. This syndrome recapitulates the proteinuria and hypertension frequently seen in patients undergoing chemotherapy with anti-VEGF monoclonal antibodies or with tyrosine kinase inhibitors and provides a model to study the role of VEGF and its receptors in glomerular endothelial cell signaling and injury. Glomerular endotheliosis also accompanies the heavy proteinuria seen in toxemia and is considered its defining pathological lesion. Serum from toxemic women stimulates the glomerular endothelial cell (GEC) to release soluble factors such as endothelin-1 (ET-1), which in turn induce nephrin shedding and actin cytoskeletal rearrangement in the podocyte, emphasizing the role of the glomerular endothelial cell in inducing proteinuria. The primary goals of this project are to identify the mechanisms that underlie the increased expression of sFlt1 in toxemia and to determine the effect of sFlt1 isoforms on glomerular endothelial cell function. We have identified novel sFtl1 isoforms that are increased in toxemia and are regulated by hypoxia. We plan to study alternate processing of the primary transcripts of FLT1, focusing on hypoxia and angiotensin II type 1 (AT1) receptor activation, two pathways that increase sFlt1 expression. We will also study the effect of plasma obtained from patients with toxemia and the effect of novel sFlt1 isoforms on GEC preproendothelin-1 expression and ET-1 release. We hypothesize that hypoxia differentially stimulates sFlt1 expression, primarily by post-transcriptional regulation of sFlt1. We also hypothesize that cis-elements within FLT1 locus regulates the abundance of Flt1 and sFlt1 transcripts. These cis-elements are predicted to be in the 5' flanking region of FLT1 coordinately regulating the transcription of Flt1 and sFlt1 and within intron 13 of FLT1 and neighboring exons reciprocally regulating Flt1 and sFlt1. We hypothesize that sFlt1 inhibits glomerular endothelial nitric oxide synthase (eNOS) and NO release which in turn increases ET-1 expression and release from GEC. We also hypothesize that the effect of toxemic serum to induce ET-1 release from GEC is attributable to the increase sFlt1 in serum. To test our hypotheses we propose the following specific aims: (i)establish the mechanisms that lead to the stimulation of sFlt1 mRNA expression by hypoxia; (ii)study the transcriptional regulation of Flt1; and (iii)determine the effect of sFlt1 isoforms on GEC nitric oxide synthesis and endothelin-1 release. We will compare the effects of the principal sFlt1 isoforms in cultured primary GEC and we will assess whether the effect of toxemic serum to increase glomerular ET-1 release is mediated through increased sFlt1. An understanding of the processes that regulate sFlt1 and the elucidation of signaling pathways in GEC has broad implication for the study of proteinuric kidney diseases and may provide new therapeutic targets for treatment of hypertension and proteinuria.

描述（由申请方提供）：在大鼠和小鼠中输注抗VEGF抗体或可溶性VEGF受体拮抗剂sFlt 1导致严重蛋白尿和高血压伴肾小球内皮增生的发展。该综合征概括了在接受抗VEGF单克隆抗体或酪氨酸激酶抑制剂化疗的患者中常见的蛋白尿和高血压，并提供了研究VEGF及其受体在肾小球内皮细胞信号传导和损伤中的作用的模型。肾小球内皮组织增生也伴随着大量蛋白尿见于毒血症，被认为是其定义性病理损害。毒血症妇女的血清刺激肾小球内皮细胞（GEC）释放可溶性因子，如内皮素-1（ET-1），这反过来又诱导足细胞中的nephrin脱落和肌动蛋白细胞骨架重排，强调肾小球内皮细胞在诱导蛋白尿中的作用。该项目的主要目标是确定毒血症中sFlt 1表达增加的机制，并确定sFlt 1亚型对肾小球内皮细胞功能的影响。我们已经确定了新的sFtl 1亚型，增加毒血症和缺氧调节。我们计划研究FLT 1初级转录物的替代加工，重点是缺氧和血管紧张素II 1型（AT 1）受体激活，这两种途径增加sFlt 1表达。我们还将研究从毒血症患者获得的血浆的效果和新的sFlt 1亚型对GEC前内皮素原-1表达和ET-1释放的影响。我们假设，缺氧差异刺激sFlt 1的表达，主要是通过转录后调节sFlt 1。我们还推测FLT 1基因座内的顺式元件调节Flt 1和sFlt 1转录本的丰度。预测这些顺式元件位于FLT 1的5'侧翼区，协调调节Flt 1和sFlt 1的转录，并位于FLT 1的内含子13和邻近的外显子内，协调调节Flt 1和sFlt 1。我们推测sFlt 1抑制肾小球内皮一氧化氮合酶（eNOS）和NO的释放，从而增加GEC的ET-1表达和释放。我们还推测，毒血清诱导GEC释放ET-1的作用是由于血清中sFlt 1的增加。为了验证我们的假设，我们提出了以下具体目标：（i）建立机制，导致刺激sFlt 1 mRNA的表达缺氧;（ii）研究Flt 1的转录调控;（iii）确定GEC一氧化氮合成和内皮素-1释放的sFlt 1亚型的影响。我们将比较培养的原代GEC中主要sFlt 1亚型的作用，并评估毒血症血清增加肾小球ET-1释放的作用是否通过增加sFlt 1介导。了解sFlt 1的调控过程和阐明GEC中的信号通路对蛋白尿肾病的研究具有广泛的意义，并可能为高血压和蛋白尿的治疗提供新的治疗靶点。