DNA2 knockout aggravates cerebral ischemia/reperfusion injury by reducing postsynaptic Homer1a

DNA2, a multifunctional enzyme with structure-specific nuclease, 5 <i>'</i>-to-3 <i>'</i> helicase, and DNA-dependent ATPase activities, plays a pivotal role in the cellular response to DNA damage. However, its involvement in cerebral ischemia/reperfusion (I/R) injury remains to be elucidated. This study investigated the involvement of DNA2 in cerebral I/R injury using conditional knockout (cKO) mice ( <i>Nestin</i>-Cre) subjected to middle cerebral artery occlusion (MCAO), an established model of cerebral I/R. Results demonstrated a gradual up-regulation of DNA2 expression, peaking at 72 h post-MCAO. Notably, <i>DNA2</i> cKO mice exhibited more pronounced brain injury, neurological deficits, and neuronal apoptosis within the penumbra following MCAO. Additionally, DNA2 expression was elevated in an oxygen-glucose deprivation/reoxygenation (OGD/R) cell culture model, and <i>DNA2</i> knockdown (KD) exacerbated neuronal apoptosis and oxidative stress. Transcriptome analysis of ischemic penumbra tissues via RNA sequencing revealed significant down-regulation of <i>Homer1</i> in <i>DNA2</i> cKO mice. Furthermore, <i>in</i> <i>vitro</i> experiments demonstrated that overexpression of <i>Homer1a</i> ameliorated <i>DNA2</i> KD-induced neuronal apoptosis. Collectively, these findings demonstrate that <i>DNA2</i> deficiency exacerbates cerebral I/R injury through the down-regulation of <i>Homer1a</i>, highlighting a novel regulatory axis in ischemic neuroprotection.