Role of Meprin A in Acute Kidney Injury

Meprin A 在急性肾损伤中的作用

• 批准号: 7790910
• 负责人: Gur Prasad Kaushal
• 金额: --
• 依托单位: CENTRAL ARKANSAS VETERANS HLTHCARE SYS
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7790910
• 关键词: Acute; Acute Kidney Failure; Acute Renal Failure with Renal Papillary Necrosis; Address; Admission activity; Affect; Animals; Apical; Binding; Biological Assay; Biological Markers; Blood Circulation; Blood Urea Nitrogen; C3H/He Mouse; CCL2 gene; CD14 gene; Cell membrane; Cells; Cisplatin; Cleaved cell; Collagen Type IV; Creatinine; Cytoplasm; Dialysis procedure; Disease; Disintegrins; Doctor of Philosophy; Early Diagnosis; Enzyme-Linked Immunosorbent Assay; Enzymes; Epithelial Cells; Excretory function; Experimental Models; Extracellular Matrix; Extracellular Matrix Degradation; Extracellular Matrix Proteins; Family; Fibronectins; Generations; Goals; Gur; Hemodialysis; Immunofluorescence Immunologic; In Vitro; Infiltration; Inflammation; Inflammatory; Injury; Interleukin-1; Interleukin-1 beta; Ischemia; Kidney; Kidney Diseases; Kidney Failure; Knockout Mice; Laminin; Leukocyte Trafficking; Leukocytes; Marrow; Matrix Metalloproteinases; Mediating; Membrane; Membrane Proteins; Meprin; Metalloproteases; Molecular; Mouse Strains; Mus; Na(+)-K(+)-Exchanging ATPase; Nephrotoxic; Nidogen; Patients; Peptide Hydrolases; Peripheral; Postoperative Period; Process; Production; Proximal Kidney Tubules; Publishing; Rattus; Recombinants; Reperfusion Therapy; Resistance; Risk; Risk Factors; Role; Serum; Site; Staining method; Stains; T-Lymphocyte; Testing; Therapeutic Intervention; Time; Tissues; Tubular formation; Urine; Veterans; Western Blotting; base; basolateral membrane; brush border membrane; chemokine; clinically relevant; cytokine; in vivo; in vivo Model; inhibitor/antagonist; insight; kidney cortex; member; meprin A; monocyte; mortality; mouse model; nephrotoxicity; new therapeutic target; overexpression; patient population; prevent; protective effect; public health relevance; response; secretase; urinary

DESCRIPTION (provided by applicant): Role of Meprin A in acute kidney injury Gur P. Kaushal, Ph.D. Project Summary Meprin A, a membrane-associated neutral metalloendoprotease, is highly expressed at the brush- border membranes of proximal tubules in the corticomedullary junction. The specific role of meprin A during acute kidney injury (AKI) is not fully understood. Our studies identified that meprin A is the major matrix-degrading protease in the rat kidney cortex capable of degrading the extracellular matrix (ECM) proteins including collagen IV, fibronectin, laminin, and nidogen in vitro. Our recently published and preliminary studies demonstrated that meprins are also capable of producing biologically active proinflammatory cytokine interleukin 1-2 from its inactive proform and proteolytically processing chemotactic cytokine MCP-1, suggesting that meprins are also important in inflammation. Following ischemia-reperfusion (IR)- and cisplatin-induced AKI, meprin A is redistributed throughout the cytoplasm and extracellularly adhering toward the basolateral plasma membrane and the cleaved form of meprin A is excreted in the urine during AKI. These studies suggest that shedding and altered localization of meprin A in places other than the apical brush-border membranes may be deleterious in vivo in acute tubular injury. How membrane-associated meprin A is redistributed and shed is not known. Preliminary studies suggest that meprin A shedding may involve a member of the ADAM (a disintegrin and metalloproteinase) family. Using in vivo models of cisplatin- and IR-induced AKI, we demonstrated that actinonin, a potent inhibitor of meprin A inhibits meprin A in vivo and ameliorates acute kidney injury and meprin A-deficient C3H/He mice are resistant to AKI. Interestingly, we observed that nidogen and meprin-beta fragments, undetectable in the urine of normal mice, increased significantly before the rise in serum creatinine during the progression of IR- and cisplatin- induced AKI. Thus, a unique opportunity exists to further explore the role and mechanism of action of meprin A in AKI. We hypothesize that meprin A, with its enormous destructive potential, is detrimental to renal proximal tubules due to altered localization during AKI and that understanding its mechanism of action is important in protecting or reducing AKI. In addition, we hypothesize that meprin and nidogen fragments excreted during AKI will serve as important biomarkers for early detection of AKI. We will test these hypotheses through the following specific aims: 1. Examine the temporal relationship between meprin A redistribution, renal injury, leukocyte infiltration, meprin A shedding, and urinary excretion of meprin subunits during AKI using experimental models of IR and cisplatin nephrotoxicity. 2. Examine meprin A-mediated in vivo degradation products of nidogen during IR and cisplatin nephrotoxicity. 3. Determine the mechanisms of meprin A-mediated inflammatory effects and functional significance of meprin A inhibition after the onset of AKI. Understanding the underlying role of meprin A in AKI will provide insights for specific therapeutic interventions to prevent acute kidney injury. PUBLIC HEALTH RELEVANCE: NARRATIVE Kidney disease due to ischemia and toxic acute kidney injury (AKI) is a frequent and serious disease, which affects 5-7% of all hospitalized patients and 30 % of ICU admissions with a high mortality rate and the risk of mortality is greater than 60% among patients who develop AKI and subsequently require hemodialysis. The expenses related with kidney failure are estimated at $10 billion per year. There has been little improvement in mortality over the last four decades. The primary goal of the current proposal is to study meprin A as a novel therapeutic target to prevent or reduce AKI and most importantly, to investigate the mechanism of its altered distribution during AKI. In addition the study will identify meprin A-mediated urinary markers for early detection of AKI. Therefore, the proposal is clinically relevant to the VA patient population since a large segment of veterans suffer from AKI.

描述（由申请人提供）： Meprin A在急性肾损伤中的作用Gur P. Kaushal，Ph.D. Meprin A是一种膜相关中性金属内切蛋白酶，在皮质髓质连接处近端小管的刷状缘膜高度表达。在急性肾损伤（阿基）的具体作用meprin A尚未完全理解。我们的研究表明，meprin A是大鼠肾皮质中的主要基质降解蛋白酶，能够在体外降解细胞外基质（ECM）蛋白，包括胶原IV，纤连蛋白，层粘连蛋白和巢蛋白。我们最近发表的和初步的研究表明，meprins也能够产生生物活性的促炎细胞因子白细胞介素1-2从其无活性的前体和蛋白水解加工趋化细胞因子MCP-1，这表明meprins在炎症中也很重要。在缺血-再灌注（IR）和顺铂诱导的阿基后，meprin A在整个细胞质中重新分布，并在细胞外粘附到基底外侧质膜，在阿基期间，meprin A的裂解形式在尿液中排泄。这些研究表明，脱落和改变定位的meprin A的地方以外的顶端刷缘膜可能是有害的，在体内急性肾小管损伤。膜相关的meprin A如何重新分布和脱落尚不清楚。初步研究表明，meprin A脱落可能涉及ADAM（一种去整合素和金属蛋白酶）家族的成员。使用顺铂和IR诱导的阿基的体内模型，我们证明了actinonin，一种有效的meprin A抑制剂，在体内抑制meprin A并改善急性肾损伤，并且meprin A缺陷的C3 H/He小鼠对阿基具有抗性。有趣的是，我们观察到在正常小鼠的尿液中检测不到的巢蛋白和meprin-β片段在IR和顺铂诱导的阿基进展期间在血清肌酐升高之前显著增加。因此，存在进一步探索meprin A在阿基中的作用和作用机制的独特机会。我们假设，具有巨大破坏潜力的meprin A由于阿基期间的定位改变而对肾近端小管有害，并且理解其作用机制对于保护或减少阿基非常重要。此外，我们假设在阿基期间排泄的meprin和巢蛋白片段将作为早期检测阿基的重要生物标志物。我们将通过以下具体目标来检验这些假设：1.使用IR和顺铂肾毒性的实验模型检查阿基期间吗啡肽A再分布、肾损伤、白细胞浸润、吗啡肽A脱落和吗啡肽亚基尿排泄之间的时间关系。2.检查IR和顺铂肾毒性期间meprin A介导的巢蛋白体内降解产物。3.确定Meprin A介导的炎症作用的机制和阿基发作后Meprin A抑制的功能意义。 了解meprin A在阿基中的潜在作用将为预防急性肾损伤的特定治疗干预提供见解。 公共卫生相关性： 由于缺血和毒性急性肾损伤（阿基）引起的肾脏疾病是一种常见且严重的疾病，其影响所有住院患者的5-7%和ICU入院的30%，具有高死亡率，并且在发生阿基并随后需要血液透析的患者中，死亡风险大于60%。与肾衰竭相关的费用估计为每年100亿美元。在过去四十年中，死亡率几乎没有改善。目前提案的主要目标是研究meprin A作为预防或减少阿基的新型治疗靶点，最重要的是研究其在阿基期间改变分布的机制。此外，该研究将确定用于早期检测阿基的meprin A介导的尿液标记物。因此，该提案与VA患者人群具有临床相关性，因为很大一部分退伍军人患有阿基。