Meprin A Metalloproteinase in Acute Kidney Injury

Meprin A 金属蛋白酶在急性肾损伤中的作用

• 批准号: 8235921
• 负责人: Gur Prasad Kaushal
• 金额: $ 20.71万
• 依托单位: UNIV OF ARKANSAS FOR MED SCIS
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8235921
• 关键词: Acute; Acute Kidney Failure; Acute Renal Failure with Renal Papillary Necrosis; Address; Adhesions; Admission activity; Affect; Animals; Apical; Basement membrane; Binding; Biological Markers; Blood Circulation; Blood Urea Nitrogen; C3H/He Mouse; CCL2 gene; CD14 gene; Cell surface; Cells; Cisplatin; Cleaved cell; Collagen Type IV; Creatinine; Cytoplasm; Dialysis procedure; Disease; Disintegrins; Enzymes; Epithelial Cells; Excretory function; Experimental Models; Extracellular Matrix; Extracellular Matrix Degradation; Extracellular Matrix Proteins; Family; Fibronectins; Future; Health; Hemodialysis; Immunofluorescence Immunologic; In Vitro; Infiltration; Inflammation; Inflammatory; Inflammatory Response; Injury; Interleukin-1 beta; Interleukins; Ischemia; Kidney; Kidney Diseases; Kidney Failure; Knockout Mice; Laminin; Leukocyte Trafficking; Leukocytes; Light; Marrow; Mass Spectrum Analysis; Mediating; Membrane; Membrane Proteins; Meprin; Metalloendopeptidases; Metalloproteases; Minor; Molecular; Mouse Strains; Movement; Mus; Na(+)-K(+)-Exchanging ATPase; Nephrotoxic; Nidogen; Patients; Peptide Hydrolases; Peripheral; Postoperative Period; Process; Proximal Kidney Tubules; Publishing; Rattus; Recombinants; Reperfusion Therapy; Resistance; Risk; Risk Factors; Role; Serum; Side; Site; Specificity; Staining method; Stains; Suggestion; T-Lymphocyte; Testing; Therapeutic Intervention; Time; Tissues; Tubular formation; Urine; astacin; base; basolateral membrane; brush border membrane; chemokine; cytokine; in vivo; in vivo Model; inhibitor/antagonist; insight; kidney cortex; macrophage; member; meprin A; migration; monocyte; mortality; mouse model; nephrotoxicity; overexpression; peripheral blood; prevent; protective effect; protein aminoacid sequence; response; response to injury; secretase; urinary

DESCRIPTION (provided by applicant): Meprins, cell-surface and secreted oligomeric metalloendopeptidases of the 'astacin' family, are highly expressed at the brush-border membranes of the kidney proximal tubules. The specific role of meprins 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-beta from its inactive proform and proteolytically processing chemotactic cytokine MCP-1, suggesting that meprins are also important in inflammation. Leukocytes isolated from the peripheral blood or the kidney tissue were found to express meprin beta. Furthermore, our studies demonstrate that, following ischemia-reperfusion- and cisplatin-induced AKI, meprin A is redistributed toward the basolateral side of the proximal tubule. These studies suggest that altered localization of meprin A in places other than the apical brush-border membranes may be deleterious in vivo in acute tubular injury. 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 ischemia- reperfusion-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 mice are resistant to cisplatin nephrotoxicity. Interestingly, we observed that nidogen and meprin-beta fragments, undetectable in the urine of normal mice, increased significantly during cisplatin nephrotoxicity and actinonin markedly prevented urinary excretion of nidogen fragments. 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. We will test the hypothesis through the following specific aims: The Specific Aims are: 1. Examine the temporal relationship between meprin A redistribution, renal injury, leukocyte infiltration, and meprin A shedding during AKI using experimental models of IR and cisplatin nephrotoxicity. 2. Identification of meprin A-mediated in vivo degradation products of the ECM components during IR and cisplatin nephrotoxicity. 3. Determine the mechanisms of meprin A-mediated inflammatory effects and functional significance of meprin A during AKI using a meprin inhibitor and meprin A-deficient mice. Understanding the underlying role of meprin A in AKI will provide insights for specific therapeutic interventions to prevent acute kidney injury. PUBLIC HEALTH RELEVANCE: Kidney disease 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 expenses related for patients with kidney failure are estimated at $10 billion per year. The risk of mortality is greater than 60% among patients who develop AKI and subsequently require hemodialysis. There has been little improvement in mortality over the last four decades. The mechanisms underlying the causes of kidney injury remain poorly defined. The studies proposed in this application are aimed directly at understanding these mechanisms, which will result in appropriate therapeutic interventions.

描述（由申请人提供）：Meprins，“astacin”家族的细胞表面和分泌的寡聚金属内肽酶，在肾近端小管的刷状缘膜高度表达。meprins在急性肾损伤（阿基）中的具体作用尚未完全了解。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-β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。发现从外周血或肾组织分离的白细胞表达meprin β。此外，我们的研究表明，缺血-再灌注和顺铂诱导的阿基后，meprin A重新分布到近端小管的基底外侧。这些研究表明，在体内急性肾小管损伤中，除了顶端刷状缘膜之外的地方的眠丙素A的定位改变可能是有害的。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。使用顺铂和缺血再灌注诱导的阿基的体内模型，我们证明了放线菌素（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缺陷小鼠对顺铂肾毒性具有抗性。有趣的是，我们观察到巢蛋白和meprin-β片段，在正常小鼠的尿液中检测不到，在顺铂肾毒性和放线菌素显着增加显着阻止尿排泄巢蛋白片段。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。我们将通过以下具体目标来检验假设：具体目标是：1。使用IR和顺铂肾毒性的实验模型检查阿基期间甲氧苄氨嘧啶再分布、肾损伤、白细胞浸润和甲氧苄氨嘧啶脱落之间的时间关系。2. IR和顺铂肾毒性期间ECM组分的meprin A介导的体内降解产物的鉴定。3.使用meprin抑制剂和meprin A缺陷小鼠确定meprin A介导的炎症作用的机制和meprin A在阿基期间的功能意义。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： 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，并且与肾衰竭患者相关的费用估计为每年100亿美元。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%。在过去四十年中，死亡率几乎没有改善。肾损伤的潜在原因的机制仍然不清楚。本申请中提出的研究旨在直接了解这些机制，这将导致适当的治疗干预。