Aminopeptidase A: A nephritogenic target antigen of nephrotoxic serum
Aminopeptidase A: A nephritogenic target antigen of nephrotoxic serum
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DOI：
10.1046/j.1523-1755.2001.059002601.x
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发表时间：
2001-02-01
影响因子：
19.6
通讯作者：
Salant, DJ
中科院分区：
文献类型：
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作者：
Chugh, S;Yuan, HP;Salant, DJ
背景。我们研究了绵羊抗大鼠肾毒性血清 (NTS) 的非补体结合部分诱导的抗体介导的肾小球损伤的潜在靶点。该模型的特点是向大鼠注射 NTS 后 24 小时内出现严重的补体和白细胞依赖性蛋白尿。方法。通过免疫沉淀法鉴定 NTS 反应性肾小球细胞和基质蛋白。蛋白质印迹分析。蛋白质测序、cDNA 文库筛选和酶联免疫吸附测定。在注射NTS的大鼠中测量蛋白尿，其中针对IV型胶原的反应性已通过免疫吸附去除，并且抗体从注射了未吸收的NTS的蛋白尿大鼠的肾小球中洗脱。确定氨肽酶 A (APA) 是 NTS 的主要靶标后，我们研究了 NTS 和抗 APA 对培养的小鼠肾小球上皮细胞的影响。结果。然而，NTS 鉴定出了几种足细胞和基质蛋白。 APA 是：唯一能与注射 NTS 的大鼠肾小球中洗脱的抗体发生反应的细胞表面蛋白。尽管洗脱液还含有对 IV 型胶原蛋白 α1 和 α3 链的非胶原结构域的反应性，但这些抗体的免疫耗竭并没有减弱 NTS 引起蛋白尿的能力。我们还记录了 APA 在培养的小鼠肾小球上皮细胞上的表面表达。并发现 NTS 和特异性抗 APA 抗体诱导抗原的时间和温度依赖性重新分布。结论。 APA 是一种 II 型整合膜金属肽酶，是 NTS 体内的主要靶标，已知存在于足细胞表面。 NTS 诱导的蛋白尿与已知的肾炎基质蛋白的反应性无关。这些结果与先前的研究相结合，表明单克隆抗 APA 抗体会在小鼠中诱导严重的蛋白尿，表明抗 APA 抗体是该模型中补体非依赖性蛋白尿的原因。
Background. We investigated potential targets of antibody-mediated glomerular injury induced with a noncomplement binding fraction of sheep anti-rat nephrotoxic serum (NTS). This model is characterized by severe complement- and leukocyte-independent proteinuria within 24 hours of NTS injection into rats.Methods. NTS-reactive glomerular cell and matrix proteins were identified by immunoprecipitation. Western blot analysis. protein sequencing, cDNA library screening, and enzyme-linked immunosorbent assay. Proteinuria was measured in rats injected with NTS from which reactivity against type IV collagen had been removed by immunoadsorption, and antibodies were eluted from the glomeruli of proteinuric rats that had been injected with unabsorbed NTS. Having identified aminopeptidase A (APA) as a major target of NTS, we studied the effect of NTS and anti-APA on mouse glomerular epithelial cells in culture.Results. NTS identified several podocyte and matrix proteins: however. APA was the: only cell surface protein reactive with antibodies eluted from the glomeruli of rats injected with NTS. Although the eluate also contained reactivity to the noncollagenous domains of alpha1 and alpha3 chains of type IV collagen, immunodepletion of these antibodies did not diminish the ability of NTS to cause proteinuria. We also documented the surface expression of APA on mouse glomerular epithelial cells in culture. and found that NTS and specific anti-APA antibodies induce a time- and temperature-dependent redistribution of the antigen.Conclusions. APA, a type II integral membrane metallopeptidase, is a major target of NTS in vivo and is known to be present on the surface of podocytes. NTS-induced proteinuria is independent of reactivity to known nephritogenic matrix proteins. These: findings, in combination with previous studies showing that monoclonal anti-APA antibodies induce severe proteinuria in mice, suggest that anti-APA antibodies are responsible For complement-independent proteinuria in this model.