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The Laminin Receptors in Kidney Fibrosis

肾纤维化中的层粘连蛋白受体

基本信息

批准号：
10368972
负责人：
ROY ZENT
金额：
$ 50.78万
依托单位：
VANDERBILT UNIVERSITY MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-06-08 至 2023-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10368972
关键词：
Adhesions Age Aging Animals Apoptosis Apoptotic Biochemical Biological Biological Assay Cell physiology Cells Chronic Chronic Kidney Failure Collagen Cytoplasmic Tail Data Defect Development Dilatation - action Disease Ductal Epithelial Cell Epithelial Cells Extracellular Domain Extracellular Matrix Fibrosis Goals Grant Health Homeostasis Human Inflammation Inflammatory Inflammatory Response Injury Injury to Kidney Integrin Binding Integrin alpha3 Integrin alpha3beta1 Integrin alpha6 Integrins Kidney Knockout Mice Knowledge Laminin Laminin Receptor Ligand Binding Ligands Mediating Metanephric Diverticulum Minor Morphology Mus Mutation Nephrotic Syndrome Null Lymphocytes Obstruction Phenotype Process Production Property Renal tubule structure Signal Pathway Signal Transduction Specificity System Testing Transgenic Mice Transmembrane Domain Tubular formation aged cell injury cytokine defined contribution dimer epithelial injury injured insight kidney epithelial cell kidney fibrosis mouse model novel receptor receptor binding response

项目摘要

Our overall goal is to define how cell-extracellular matrix interactions regulate kidney homeostasis in health and disease. These interactions are studied from animals to molecules using transgenic mouse models, cell biological and biochemical assays. We previously defined the contribution of laminin (LM) receptor integrins, integrin α3β1 and α6 containing integrins, to ureteric bud (UB) development. Recently, we made an unexpected novel observation that LM receptors regulate tubular epithelial cell inflammation and kidney tubulointerstitial fibrosis in aged and injured mice. These new findings form the basis of this renewal. Integrins are transmembrane receptors composed of α and β subunits that mediate interactions between cells and ECM. There are 18 α and 8 β subunits, which form dimers with different ligand binding properties. Integrins are classified into collagen, LM and RGD binding receptors and the principal LM binding integrins are α3β1, α6β1 and α6β4. Ligand specificity is defined by the extracellular domain while the transmembrane domain (TM) and the cytoplasmic tail mediate specialized functional intracellular signaling. In the last grant cycle, we showed that deleting the integrin (Itg) α3 subunit in the UB causes minor morphological developmental abnormalities, while deleting the Itgα6 subunit did not alter development. Mice lacking Itgα3 in the UB are highly susceptible to kidney fibrosis after unilateral ureteric obstruction (UUO), while the integrin Itgα6-null mice develop severe tubular dilatation and cellular apoptosis, but no fibrosis. Mice lacking all LM binding integrins in the UB (Itgα3/α6- null) have the same developmental phenotype as the Itgα3-null mice, but with age they develop severe tubulointerstitial fibrosis and inflammation. These mice are also susceptible to severe inflammation, fibrosis and tubular apoptosis after UUO and chronic proximal tubule injury. Utilizing collecting duct cells from these mice, we show that in addition to their classical adhesion functions, the LM binding integrins regulate epithelial cell apoptosis, inflammation and collagen production. Excess collagen synthesis occurs when Itgα3 is deleted, apoptosis when α6 is deleted and, in addition to these processes, inflammation occurs in Itgα3/α6-null mice. In this proposal, we will investigate the mechanisms whereby the LM-binding receptors regulate renal tubular epithelial cell responses to aging and injury. We will test the hypothesis that loss of kidney tubule epithelial cell signaling from LMs, via α3β1 an α6-containing integrins, causes accelerated inflammation and excessive fibrosis and apoptosis resulting in chronic kidney disease in the following aims: 1) Define the mechanisms whereby loss of LM binding integrin signaling predisposes kidney tubules to chronic kidney injury. 2) Determine the mechanisms whereby the loss of LM binding integrin signaling promotes renal tubular epithelial cell apoptosis, inflammation and collagen production.

我们的总体目标是确定细胞-细胞外基质相互作用如何调节健康肾脏的稳态，疾病使用转基因小鼠模型、细胞模型和细胞模型，生物学和生物化学测定。我们先前定义了层粘连蛋白（LM）受体整联蛋白的贡献，含整合素α3β1和α6的整合素参与输尿管芽（UB）发育。最近，我们做了一个意想不到的 LM受体调节肾小管上皮细胞炎症和肾小管间质的新观察老年和受伤小鼠的纤维化。这些新发现构成了这一更新的基础。整合素是由α和β亚基组成的跨膜受体，介导细胞间的相互作用 ECM。有18个α和8个β亚基，它们形成具有不同配体结合特性的二聚体。整合素分为胶原、LM和RGD结合受体，主要的LM结合整联蛋白是α3β1， α6β1和α6β4。配体特异性由胞外结构域定义，而跨膜结构域（TM）胞质尾介导专门的功能性胞内信号传导。在上一个资助周期中，在UB中缺失整合素（Itg）α3亚基会导致轻微的形态发育异常，而删除Itgα6亚基并不改变发育。UB中缺乏Itgα3的小鼠高度易感单侧输尿管梗阻（UUO）后肾纤维化，而整合素Itgα6缺失小鼠出现严重的肾小管扩张和细胞凋亡，但无纤维化。UB中缺乏所有LM结合整合素的小鼠（Itgα3/α6- null）与Itgα3-null小鼠具有相同的发育表型，但随着年龄的增长，肾小管间质纤维化和炎症。这些小鼠也容易受到严重的炎症，纤维化和 UUO和慢性近端小管损伤后肾小管细胞凋亡。利用收集这些小鼠的导管细胞，我们发现，除了经典的粘附功能外，LM结合整合素还调节上皮细胞细胞凋亡、炎症和胶原蛋白产生。当Itgα3缺失时，会发生过量的胶原蛋白合成，在Itgα3/α6缺失小鼠中，除了这些过程外，还发生了炎症。在因此，我们将研究LM结合受体调节肾小管功能的机制。上皮细胞对衰老和损伤的反应。我们将检验肾小管上皮细胞的缺失 LM通过α3β1和含α6的整联蛋白发出的细胞信号会导致炎症加速，过度的纤维化和细胞凋亡导致慢性肾脏疾病，其目的如下：1）定义 LM结合整联蛋白信号传导的丧失使肾小管易于慢性炎症的机制肾损伤2)确定LM结合整合素信号传导的丧失促进肾小管上皮细胞凋亡、炎症和胶原生成。