Aβ1-40 induces venular endothelial cell ferroptosis in cerebral amyloid angiopathy via the ATF3/xCT axis: Insights from single-cell RNA sequencing.

INTRODUCTION: Amyloid-beta (Aβ)-induced microvascular injury is a key pathological feature of cerebral amyloid angiopathy (CAA). Recent evidence suggests that ferroptosis is implicated in Aβ pathology; however, its cell-type specificity and regulatory mechanisms within the cerebral microvasculature in CAA remain unclear. METHODS: Single-cell RNA sequencing (scRNA-seq) was performed on cortical microvessels from 11-month-old APP23 mice and wild-type littermates to identify cell-type-specific ferroptosis signatures. Biochemical, histopathological, and intervention experiments were further conducted to validate the findings and investigate the underlying mechanisms. RESULTS: Venous endothelial cluster exhibited the most prominent enrichment of ferroptosis signatures in scRNA-seq analysis, with subsequent experiments demonstrating progressive ferroptosis-related alterations in cortical venular endothelial cells (vECs) during CAA development. Mechanistically, Aβ1-40 increased activating transcription factor 3 (ATF3) expression and its occupancy at the Slc7a11 promoter, whereas ATF3 silencing restored Slc7a11/xCT expression, supporting ATF3-mediated Slc7a11/xCT repression and consequent impairment of glutathione-dependent antioxidant defense. Importantly, endothelial ATF3 knockdown attenuated ferroptosis-related alterations in vECs, reduced cerebral Aβ burden, and ameliorated cognitive deficits in APP23 mice. DISCUSSION: This study uncovers a previously underrecognized Aβ-driven microvascular injury characterized by vEC ferroptosis and highlights the ATF3/xCT axis as a potential therapeutic target in the early stage of CAA.