p38 mitogen-activated protein kinase (MAPK) is a major player in mitochondrial dysfunction after subarachnoid hemorrhage (SAH). Moreover, DJ-1, which responds to oxidative stress and translocates to mitochondria, maintains mitochondrial homeostasis. Although a few studies have demonstrated that DJ-1 indirectly regulates p38 activation, the relationship between DJ-1 and p38 in mitochondrial dysfunction after SAH has not been delineated. Using an in vitro SAH model, alterations in p38, p-p38, DJ-1, and autophagic-related protein expression were detected. As expected, p38 inhibitor significantly blocked excessive expression of p38 and p-p38 after SAH, whereas total DJ-1 expression and mitochondrial DJ-1 were up-regulated. Further analysis showed that p38 inhibitor significantly blocked oxyhemoglobin (OxyHb) induced mitochondrial dysfunction, including mitochondrial membrane potential depolarization and reactive oxygen species (ROS) release. In addition, p38 inhibitor restored OxyHb-induced abnormal autophagic flux at the initiation and formation stage by regulating Atg5, beclin-1, the ratio of LC3-II/LC3-I, and p62 expression. This study suggested that overexpression of p38 induced the accumulation of mitochondrial dysfunction partly due to abnormal activation of autophagy, which largely relied on DJ-1 mitochondrial translocation.
Keywords: Autophagy; DJ-1; Mitochondrial dysfunction; ROS; p38.