Calpastatin overexpression prevents progression of S-1.2-dichlorovinyl-L-cysteine (DCVC)-initiated acute renal injury and renal failure (ARF) in diabetes
Calpastatin overexpression prevents progression of S-1.2-dichlorovinyl-L-cysteine (DCVC)-initiated acute renal injury and renal failure (ARF) in diabetes
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DOI：
10.1016/j.taap.2006.01.018
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发表时间：
2006-09-01
影响因子：
3.8
通讯作者：
Mehendale, Harihara M.
中科院分区：
文献类型：
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作者：
Dnyanmote, Ankur V.;Sawant, Sharmilee P.;Mehendale, Harihara M.
先前我们已经表明，90%的链脲佐菌素（STZ）诱导的1型糖尿病（DB）小鼠从急性肾衰竭（ARF）和正常LD 90剂量（75 mg/kg，i. p.）肾毒性物质S-1，2-二氯乙烯基-L-半胱氨酸（DCVC）。这种显著的保护作用是由于DCVC引发的肾损伤进展较慢和DB肾脏中代偿性肾源性组织修复增加的组合。BRDU免疫组化显示DB条件导致4倍更高数量的近端肾小管细胞（PTC）进入细胞周期的S期。在本研究中，我们测试了一个假设，即DB诱导的PTC进入S期的增加伴随着钙蛋白酶抑制剂钙蛋白酶抑制素的过表达，钙蛋白酶抑制素内源性地阻止了由钙蛋白酶从受损PTC中逃逸介导的DCVC引发的肾损伤的进展。肾钙蛋白酶的免疫组织化学检测及其在尿中的活性，在用LD 50剂量的DCVC治疗后的一段时间内，表明与DB肾相比，钙蛋白酶渗漏到非糖尿病（NDB）肾的损伤PTC的细胞外间隙中的进行性增加。随着时间的推移，使用免疫组化，在NDB肾脏中检测到最低限度的钙蛋白酶抑制蛋白表达。另一方面，DB肾脏中持续较高数量的小管显示钙蛋白酶抑制蛋白表达随时间推移而增加。DB肾脏中钙蛋白酶的较低渗漏与这些小鼠的S期负载PTC中钙蛋白酶抑制蛋白的组成性较高表达相称。为了测试新分裂的/正在分裂的PTC的保护作用，给DB小鼠施用抗有丝分裂剂秋水仙碱（CLC）（2 mg/kg和1.5mg/kg，腹膜内，在STZ注射后第8天和第10天），然后用LD 90剂量的DCVC攻击，这导致48小时内100%的死亡率。死亡率是由于DCVC引发的肾损伤的快速进展，表明新分裂/分裂的细胞有助于减轻DB中DCVC引发的肾损伤的进展。CLC在DB肾中的抗有丝分裂作用与受损肾小管中钙蛋白酶抑制蛋白的表达降低和钙蛋白酶的渗漏增加有关。这些研究结果表明，DB肾中组成性较高的细胞分裂与钙蛋白酶抑制蛋白的过表达相关，这一方面减少了由钙蛋白酶介导的DCVC启动的肾损伤的进展，另一方面加速了肾源性组织修复，从而恢复了肾脏结构和功能。(c)2006年爱思唯尔公司All rights reserved.
Previously we have shown that 90% of streptozotocin (STZ)-induced type-1 diabetic (DB) mice survive from acute renal failure (ARF) and death induced by a normally LD90 dose (75 mg/kg, i.p.) of the nephrotoxicant S-1,2-dichlorovinyl-L-eysteine (DCVC). This remarkable protection is due to a combination of slower progression of DCVC-initiated renal injury and increased compensatory nephrogenic tissue repair in the DB kidneys. BRDU immunohistochemistry revealed that the DB condition led to 4-fold higher number of proximal tubular cells (PTC) entering S-phase of cell cycle. In the present study, we tested the hypothesis that DB-induced augmentation of PTC into S-phase is accompanied by overexpression of the calpain-inhibitor calpastatin, which endogenously prevents the progression of DCVC-initiated renal injury mediated by the calpain escaping out of damaged PTCs. Immumohistochemical detection of renal calpain and its activity in the urine, over a time course after treatment with the LD50 dose of DCVC, indicated progressive increase in leakage of calpain into the extracellular spaces of the injured PTCs of the non-diabetic (NDB) kidneys as compared to the DB kidneys. Calpastatin expression was minimally detected in the NDB kidneys, using immumohistochemistry, over the time course. On the other hand, consistently higher number of tubules in the DB kidney showed calpastatin expression over the time course. The lower leakage of calpain in the DB kidneys was commensurate with constitutively higher expression of calpastatin in the S-phase-laden PTCs of these mice. To test the protective role of newly divided/dividing PTCs, DB mice were given the antimitotic agent colchicine (CLC) (2 mg/kg and 1.5 mg/kg, i.p., on days 8 and 10 after STZ injection) prior to challenge with a LD90 dose of DCVC, which led to 100% mortality by 48 h. Mortality was due to rapid progression of DCVC-initiated renal injury, suggesting that newly divided/ dividing cells are instrumental in mitigating the progression of DCVC-initiated renal injury in DB. The anti-mitotic effect of CLC in DB kidney was associated with lower expression of calpastatin and higher leakage of calpain in the injured tubules. These findings suggest that constitutively higher cell division in the DB kidney is associated with overexpression of calpastatin, which reduces the progression of DCVC-initiated renal injury mediated by calpain on the one hand and accelerates nephrogenic tissue repair on the other, thereby restoring renal structure and function. (c) 2006 Elsevier Inc. All rights reserved.