Autophagy and poly(ADP-ribose) polymerase 1 (PARP-1) are activated and involved in a series of cell processes under oxidative stress, which is associated with pathogenesis of atherosclerosis. Research on their relationship under oxidative stress has been limited. In this study, we aimed to investigate the activation, relationship, and role of autophagy and PARP-1 in vascular smooth muscle cell (VSMC) death under oxidative stress. This study ex-plored the signal molecule PARP-1 and autophagy in VSMCs using gene silencing and the hydrogen peroxide (H2O2)-stimulated oxidative stress model. We observed that H2O2 could induce autophagy in VSMCs, and the inhibition of autophagy could protect VSMCs against oxidative stress-mediated cell death. Meanwhile, PARP-1 could also be activated by H2O2. Additionally, we analysed the regulatory role of PARP-1 in oxidative stress-mediated autophagy and found that PARP-1 was a novel factor involved in the H2O2-induced autophagy via the AMPK-mTOR pathway. Finally, PARP-1 inhibition protected VSMCs against caspase-dependent apoptosis. These data suggested that PARP-1 played a critical role in H2O2-mediated autophagy and both of them were involved in apoptosis of VSMCs. and Corresponding author: Guoxian Qi
a1_We investigated the potential neuroprotective effect of transient hypertension on neuronal cell death induced by ischemia-reperfusion. Recovery of neurons, terminally differentiated cells, is almost entirely dependent upon active transcription and repair of DNA damage. We focused on the histochemical detection of distribution of NOR (argyrophylic nucleolar proteins) reflecting nucleolar integrity, immunohistochemical detection of PARP-1 (poly(ADP-ribose) polymerase-1), MADD (mitogen-activated death domain), a protein accumulated in nucleoli upon stimulation by ischemia, the active form of caspase-3, a universal proteolytic enzyme of apoptosis. The terminal deoxynucleotidyl-transferase (TdT)-mediated dUTP-biotin nick-end-labeling method (TUNEL) proved the presence of in situ DNA fragmentation. We used the model of transient focal cerebral ischemia in rats with occlusion of middle cerebral artery. In experimental group of rats, the transient hypertension was induced by constriction of the abdominal aorta. The period of ischemia lasted 15, 30, 60 and 120 min followed by 48 h of reperfusion. We examined the frontal lobe of the ipsilateral hemisphere for apoptosis of neurons and compared it with the intact brain tissue. In normotensive rats with transient focal cerebral ischemia, we found disintegrated nucleoli of cortical as well as subcortical neurons at all investigated periods of ischemia, whereas the neurons of intact animals showed compact nucleoli with a few satellites. Nuclear positivity for MADD and PARP-1 was apparent in the neocortex after 15 min and peaked after 30 min of ischemia. On the other hand, the subcortical neurons showed nuclear positivity after 60 and 120 min. The immunohistochemical reaction for active caspase 3 was apparent after 30 min onwards predominantly in the cortex. The TUNEL staining was distinct after 60 and 120 min., a2_In hypertensive rats, we found nucleolar disintegration, positivity for MADD, PARP-1 and caspase 3 after 30 min cortically and subcortically, followed by TUNEL positive staining of cortical neurons after 60 and 120 min. In summary, we detected delayed activation of neuronal apoptosis in transiently hypertensive rats with focal cerebral ischemia compared to normotensive animals. The apoptotic phenotype was confirmed by a panel of complementary methods showing rapid proteolysis-nucleolar segregation, MADD, PARP-1 and caspase-3 positivity as well as ultimate DNA fragmentation proved by the TUNEL assay., M. Smrčka, M. Horký, F. Otevřel, Š. Kuchtíčková, V. Kotala, J. Mužík., and Obsahuje bibliografii