ABSTRACT NUMBER: ESOC2026A882 TET2 DEFICIENCY EXACERBATES CEREBRAL CELLULAR SENESCENCE VIA SPP1-MEDIATED SENESCENT CELL CROSSTALK AFTER ISCHEMIC STROKE

Abstract Background and aims Cellular senescence is recognized as a critical pathogenic mechanism in acute ischemic stroke (AIS) that is closely linked to poor clinical outcomes. Epigenetics, especially 5-hydroxymethylcytosine (5hmC) plays an important role in both AIS and cellular senescence processes. Ten-Eleven-Translocation 2 (Tet2) has been confirmed to be a key protein that regulates the modification of the gene 5hmC after cerebral ischemia-reperfusion injury. However, no studies have examined the role of Tet2 in cellular senescence after IS. Methods Single-cell RNA sequencing (scRNA-seq) analyzed cellular senescence in animal models and patient samples, with validation via β-galactosidase (SA-β-GAL) staining, immunofluorescence, and reverse transcription quantitative polymerase chain reaction (RT-qPCR). Results Nestin-Cre+/-Tet2flox/flox (Tet2cKO) mice showed SA-β-gal-positive cells 24h post-transient middle cerebral artery occlusion (tMCAO), confirming Tet2 deficiency promotes ischemia-induced senescence. The SenMayo gene set constructed a brain senescence single-cell atlas for tMCAO mice and human IS patients, verifying senescence-related gene expression changes. Spp1-mediated pericyte-senescent cell crosstalk dominated senescent-neurovascular cell communication, with Spp1 activity elevated without Tet2. Five pericyte subpopulations were identified, including ischemia-specific subgroup 4 associated with degeneration; Spp1 drives its differentiation. Vitamin C, a Tet2 activator, reduced senescence-related genes/proteins in mice and patients. Conclusions Our findings delineate the comprehensive landscape of cellular senescence in brain tissues subjected to acute ischemic injury and highlight that Tet2 upregulation constitutes a promising early therapeutic strategy for combating cellular senescence. This approach enables the concurrent targeting of multiple dysregulated cell types within the neurovascular unit (NVU), thereby ameliorating functional outcomes in ischemic stroke. Conflict of interest Xiaojing Li:nothing to disclose. Jingwei Li:nothing to disclose. Zengling Cai:nothing to disclose. Xinya Chen:nothing to disclose.