Guicciardi M E, Miyoshi H, Bronk S F, Gores G J
Division of Gastroenterology and Hepatology, Mayo Medical School, Clinic, and Foundation, Rochester, Minnesota 55905, USA.
Am J Pathol. 2001 Dec;159(6):2045-54. doi: 10.1016/s0002-9440(10)63056-8.
Tumor necrosis factor-alpha (TNF-alpha) contributes to liver injury by inducing hepatocyte apoptosis. Recent evidence suggests that cathepsin B (cat B) contributes to TNF-alpha-induced apoptosis in vitro. The aim of the present study was to determine whether cat B contributes to TNF-alpha-induced hepatocyte apoptosis and liver injury in vivo. Cat B knockout (catB(-/-)) and wild-type (catB(+/+)) mice were first infected with the adenovirus Ad5I kappa B expressing the I kappa B superrepressor to inhibit nuclear factor-kappa B-induced survival signals and then treated with murine recombinant TNF-alpha. Massive hepatocyte apoptosis with mitochondrial release of cytochrome c and activation of caspases 9 and 3 was detected in catB(+/+) mice 2 hours after the injection of TNF-alpha. In contrast, significantly less hepatocyte apoptosis and no detectable release of cytochrome c or caspase activation occurred in the livers of catB(-/-) mice. By 4 hours after TNF-alpha injection, only 20% of the catB(+/+) mice were alive as compared to 85% of catB(-/-) mice. Pharmacological inhibition of cat B in catB(+/+) mice with L-3-trans-(propylcarbamoyl)oxirane-2-carbonyl-L-isoleucyl-L-proline (CA-074 Me) also reduced TNF-alpha-induced liver damage. The present data demonstrate that a cat B-mitochondrial apoptotic pathway plays a pivotal role in TNF-alpha-induced hepatocyte apoptosis and liver injury.
肿瘤坏死因子-α（TNF-α）通过诱导肝细胞凋亡导致肝损伤。最近的证据表明，组织蛋白酶B（组织蛋白酶B）在体外促成TNF-α诱导的凋亡。本研究的目的是确定组织蛋白酶B在体内是否促成TNF-α诱导的肝细胞凋亡和肝损伤。首先用表达IκB超抑制因子的腺病毒Ad5IκB感染组织蛋白酶B基因敲除（catB(-/-)）和野生型（catB(+/+)）小鼠，以抑制核因子-κB诱导的生存信号，然后用小鼠重组TNF-α进行治疗。在注射TNF-α后2小时，在catB(+/+)小鼠中检测到大量肝细胞凋亡，伴有细胞色素c从线粒体释放以及半胱天冬酶9和3的激活。相比之下，catB(-/-)小鼠肝脏中的肝细胞凋亡明显较少，未检测到细胞色素c释放或半胱天冬酶激活。在注射TNF-α后4小时，只有20%的catB(+/+)小鼠存活，而catB(-/-)小鼠的存活率为85%。用L-3-反式-（丙基氨基甲酰基）环氧乙烷-2-羰基-L-异亮氨酰-L-脯氨酸（CA-074 Me）对catB(+/+)小鼠进行组织蛋白酶B的药理学抑制也减少了TNF-α诱导的肝损伤。目前的数据表明，组织蛋白酶B-线粒体凋亡途径在TNF-α诱导的肝细胞凋亡和肝损伤中起关键作用。
