Edelstein Charles L, Hoke Thomas S, Somerset Hilary, Fang Wenfeng, Klein Christina L, Dinarello Charles A, Faubel Sarah
University of Colorado Health Science Center, Department of Internal Medicine, Denver, CO 80262, USA, and Division of Pulmonary and Critical Care Medicine, Chang Gung Memorial Hospital, Kaohsiung Medical Center, Taiwan.
Nephrol Dial Transplant. 2007 Apr;22(4):1052-61. doi: 10.1093/ndt/gfl775. Epub 2007 Jan 25.
Caspase-1 is a proinflammatory caspase via activation of the cytokine IL-18. We have recently demonstrated that the caspase-1-mediated production of IL-18 plays a deleterious role in ischaemic acute renal failure (ARF) which is independent of neutrophils and CD4+ T cells. The role of caspase-1 in hypoxia-induced membrane injury of proximal tubules (PT) in vitro is unknown.
Freshly isolated mouse PT exposed to 25 min of hypoxia were used to study the role of caspases, caspase-1 and IL-18 in hypoxia-induced membrane injury. Lactate dehydrogenase (LDH) release into the PT medium was used as a biochemical parameter of cell membrane damage. IL-18 was determined by enzyme-linked immunosorbent assay (ELISA) and immunoblotting.
PT pre-incubated with the novel pancaspase inhibitor IDN-8050 were protected; LDH release (%) was 35+/-3 in vehicle-treated hypoxic PT and 21+/-2 in IDN-8050-treated hypoxic PT (P<0.01, n=6). To investigate the mechanism of protection and examine the role of caspase-1 specifically, PT were isolated in parallel from wild-type and caspase-1- deficient (-/-) mice. PT from caspase-1-/-mice demonstrated less hypoxia-induced membrane injury. LDH release was 37+/-2 in wild-type hypoxic PT and 28+/-2 in caspase-1-/-hypoxic PT (P<0.01, n=12). IL-18 was detected in PT by immunoblotting and ELISA. PT pre-incubated with IL-18 binding protein, an inhibitor of IL-18, were not protected.
These studies demonstrate a deleterious effect of the proinflammatory caspase, caspase-1, on PT in vitro in the absence of inflammatory cells and vascular effects.
半胱天冬酶 -1是一种通过激活细胞因子白细胞介素 -18发挥作用的促炎半胱天冬酶。我们最近证明，半胱天冬酶 -1介导的白细胞介素 -18产生在缺血性急性肾衰竭（ARF）中起有害作用，且该作用独立于中性粒细胞和CD4 + T细胞。半胱天冬酶 -1在体外缺氧诱导的近端肾小管（PT）膜损伤中的作用尚不清楚。
将新鲜分离的小鼠PT暴露于25分钟的缺氧环境中，以研究半胱天冬酶、半胱天冬酶 -1和白细胞介素 -18在缺氧诱导的膜损伤中的作用。乳酸脱氢酶（LDH）释放到PT培养基中被用作细胞膜损伤的生化参数。白细胞介素 -18通过酶联免疫吸附测定（ELISA）和免疫印迹法测定。
用新型泛半胱天冬酶抑制剂IDN - 8050预孵育的PT受到保护；在未处理的缺氧PT中，LDH释放率（%）为35±3，而在IDN - 8050处理的缺氧PT中为21±2（P<0.01，n = 6）。为了研究保护机制并特别研究半胱天冬酶 -1的作用，从野生型和半胱天冬酶 -1缺陷（-/-）小鼠中平行分离PT。来自半胱天冬酶 -1-/-小鼠的PT表现出较少的缺氧诱导的膜损伤。在野生型缺氧PT中LDH释放率为37±2，而在半胱天冬酶 -1-/-缺氧PT中为28±2（P<0.01，n = 12）。通过免疫印迹和ELISA在PT中检测到白细胞介素 -18。用白细胞介素 -18结合蛋白（一种白细胞介素 -18抑制剂）预孵育的PT未受到保护。
这些研究表明，在没有炎症细胞和血管效应的情况下，促炎半胱天冬酶半胱天冬酶 -1在体外对PT有有害作用。
