Effect of an AAV1 containing an sh-RNA targeting Angptl2 on the hypocampus of male and female atherosclerotic mice

Cerebral accumulation of inflammatory senescent cells (SnC) may compromise the continuum between endothelial (EC) and neuronal function, leading to vascular cognitive impairment (VCI). We hypothesized that targeted elimination of vascular SnC will preserve cerebrovascular and neuronal functions in atherosclerotic mice of both sexes, demonstrating the causal contribution of SnC in cognitive decline. Male and female atherosclerotic mice (ATX; LDLR-/-;hApoB+/+, n=12 per group) of 6-month of age were treated twice over 3 months with an adeno-associated virus-1 delivering a shRNA targeting vascular Angptl2, a strong inflammatory factor of SnEC; a sh-scramble was used as a control. The Morris water maze test assessed cognition. In males, targeting vascular SnC had no effect on short-term memory but improved long-term memory (p<0.05 vs. sh-scramble); in contrast, in females, the treatment reduced short-term memory (p<0.05), and had no effect on long-term memory. Endothelium-dependent flow-mediated dilations in pressurized cerebral arteries were improved (p<0.05) by the treatment in both males and females. Single-nuclei RNA-sequencing (hippocampal region) revealed a strong sexual dimorphism in transcriptomics profile, with the overexpression of senescence pathways only in male vascular cells. The analysis also revealed that male sex predicted the response to the sh-Angptl2 in oligodendrocytes progenitor cells and neurons (AUC>0.8). Accordingly, the sh-Angptl2 reduced the number of EC expressing angptl2 in males (-75%), but not in females (-10%). In conclusion, these data demonstrate a sexual dimorphism in the causal contribution of vascular senescence in cerebrovascular dysfunction and cognitive impairment: only in male atherosclerotic mice, vascular senescence contributes to VCI. Overall design: Nuclei were isolated from the hypocampus of 12 mice randomly treated with an AAV1 containing an sh-RNA control (SCR) or targeting Angptl2. Mice were treated with the virus at 6 months old and 7 and a half months old before sacrifice at 9 months old. Our dataset include 3 males SCR, 3 males Angptl2, 3 females SCR and 3 females Angptl2.