Department of Pathology, Neuroproteomics Platform National Neuroscience Facility, The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia.
J Neuropathol Exp Neurol. 2011 Feb;70(2):143-50. doi: 10.1097/NEN.0b013e3182084a8c.
Activation of the caspase family of cysteine proteases is proposed to be an important cell death mechanism in transmissible spongiform encephalopathies or prion diseases. We determined the extent of caspase activation in the brain and peripheral organs of mice that showed clinical signs after intracerebral inoculation with mouse-adapted prions by in vivo administration of a red fluorescent pan-caspase inhibitor, sulforhodamine B-Val-Ala-Asp(OMe)-fluoromethylketone. Fluorescence reflectance imaging identified a significant increase in active caspases in brains of prion-infected, but not uninfected, mice that correlated with increases in procaspase-3 and cleaved caspase-3, a central effector caspase, assessed by Western immunoblot analysis. Fluorescence was found in brain regions in which neuronal loss occurs; immunohistochemical analysis indicated that fluorescence was localized within and adjacent to deposits of abnormal disease-associated conformers of the prion protein (PrP Sc). Fluorescence was also significantly increased in the kidney, lung, and ileum of prion-infected mice. This premortem labeling of caspase activation in the brain, and importantly in peripheral organs, could be exploited as a biomarker for longitudinal monitoring of prion disease progression and the impact of therapy in vivo in addition to, or independently of, PrP and spongiform changes.
半胱氨酸蛋白酶天冬氨酸家族的激活被认为是传染性海绵状脑病或朊病毒病中重要的细胞死亡机制。我们通过体内给予红色荧光泛半胱氨酸蛋白酶抑制剂，磺酰罗丹明 B-Val-Ala-Asp(OMe)-氟甲基酮，检测到在感染鼠朊病毒的小鼠出现临床症状后，大脑和外周器官中半胱氨酸蛋白酶的激活程度。荧光反射成像确定，在感染朊病毒但未感染的小鼠的大脑中，活性半胱氨酸蛋白酶显著增加，与中央效应半胱氨酸蛋白酶 procaspase-3 和 cleaved caspase-3 的增加相关，通过 Western 免疫印迹分析评估。荧光出现在发生神经元丢失的脑区；免疫组织化学分析表明，荧光定位于朊病毒蛋白（PrP Sc）异常疾病相关构象的沉积物内和周围。在感染朊病毒的小鼠的肾脏、肺和回肠中，荧光也显著增加。这种在大脑中，重要的是在周围器官中，对半胱氨酸蛋白酶激活的生前标记，可以作为体内纵向监测朊病毒病进展和治疗效果的生物标志物，除了（或独立于）PrP 和海绵状变化之外。
