Glial Scar Stiffness Affects NSCs Differentiated Direction via Piezo1 Post-Stroke.

Abstract

Following ischemic stroke, the progressive formation and mechanical stiffening of the glial scar pose a critical microenvironmental barrier to neural regeneration. However, how this dynamic stiffness influences the fate of neural stem cells (NSCs) remains unclear. To address this, this study aimed to elucidate the mechanotransduction mechanism regulating NSCs differentiation post-stroke. Specifically, thirty male C57BL/6J mice underwent distal middle cerebral artery occlusion to establish a focal cerebral ischemia model. We combined in vivo transplantation of NSCs into distal middle cerebral artery occlusion mouse stroke models and in vitro culture on polyacrylamide hydrogels mimicking scar stiffness. Furthermore, transcriptomic analysis and functional validation through Piezo1 knockdown were employed. Mechanistic insights were explored by examining calcium influx and the Notch signaling pathway. We found that increased substrate stiffness potently inhibited neuronal differentiation and neurite outgrowth. Importantly, Piezo1 was identified as a key mechanosensitive regulator and its knockdown severely diminished both the neuronal differentiated direction and the NSCs proliferation. Mechanistically, Piezo1-mediated calcium influx modulated Notch signaling, forming a stiffness-sensing axis that coordinates the differentiation gene network. Overall, these findings identify aberrant mechanosensing as an important contributing factor of neurogenesis and highlight Piezo1 as a potential therapeutic target for enhancing neural repair.