TBC1Domain Family Member 25 deficiency aggravates cerebral ischemia‐reperfusion injury via TAK1‐JNK/p38 pathway

Abstract TBC1Domain Family Member 25 (TBC1D25) is a protein that contains a TBC/RAB‐GTPase activating protein (GAP) domain, which was shown to participate in autophagy in previous studies. However, the role of TBC1D25 in cerebral ischemia‐reperfusion (I/R) injury remains unknown. In this study, we found that the mRNA and protein expression levels of TBC1D25 decreased in mouse brain after I/R injury and primary cortical neurons treated with oxygen and glucose deprivation/reoxygenation (OGD/R). Then TBC1D25 knockout (KO) mice were applied to demonstrate that TBC1D25 ablation aggravated cerebral I/R‐induced neuronal loss and infarct size. In addition, neuronal apoptosis and inflammation were significantly potentiated in the TBC1D25‐KO group. In in vitro OGD/R model, TBC1D25 knockdown can attenuate neuronal cell viability and aggravate the process of inflammation and apoptosis. Conversely, over‐expression of TBC1D25 in primary neurons ameliorated the aforementioned processes. Mechanistically, RNA‐sequencing (RNA‐seq) analysis revealed mitogen‐activated protein kinase (MAPK) signaling pathway was the most significant pathway that contributed to TBC1D25‐mediated brain I/R injury process. Through experimental verification, TBC1D25 deficiency increased the phosphorylation of the transforming growth factor‐β‐activated kinase 1 (TAK1)‐c‐Jun N‐terminal kinase (JNK)/p38 axis in neurons during the brain I/R injury. Furthermore, we found that TAK1 blockade abrogated the apoptosis and inflammatory response produced by TBC1D25 knockdown in vitro. In conclusion, this study is the first to demonstrate the functional significance of TBC1D25 in the pathophysiology of brain I/R injury, and the protective mechanism of TBC1D25 is dependent on the TAK1‐JNK/p38 pathway. image