Notch Signaling Regulates the Neuroprotective Effects of hUCMSCs in a Mouse Model of Cerebral Ischemia

Abstract

Human umbilical cord mesenchymal stem cells (hUCMSCs) have shown promise for treating ischemic stroke (IS) by promoting neural repair. The Notch signaling pathway is known to regulate neural stem cell (NSC) proliferation and differentiation, but its role in hUCMSC-mediated neuroprotection remains unclear. This study aimed to evaluate the therapeutic effects of hUMSCs in a mouse model of middle cerebral artery occlusion (MCAO) and investigate the involvement of the Notch pathway. Fifth generation of hUCMSCs were characterized by flow cytometry. In vitro, hUCMSCs were induced to differentiate with or without DAPT (a Notch inhibitor) or Jagged1 (a Notch agonist), and neural differentiation was assessed by Nestin and MAP2 expression. In vivo, MCAO mice received hUCMSC transplantation, and NSC proliferation, differentiation, and neural repair were evaluated using BrdU/Nestin immunofluorescence, qRT-PCR, Western blot, mNSS scoring, TTC, Nissl, and TUNEL assays. HUCMSCs displayed typical mesenchymal markers (CD90, CD44, CD105, and CD73) and low expression of hematopoietic markers. In vitro, DAPT enhanced hUCMSC differentiation into neuron-like cells, while JAG1 reversed this effect, confirming the mechanistic role of Notch signaling. In MCAO mice, hUCMSC transplantation promoted NSC proliferation and differentiation in the SVZ, reduced infarct volume and water content, increased Nissl-positive neurons, decreased apoptotic cells, and lowered mNSS scores. Inhibition of Notch signaling further augmented these therapeutic effects. HUCMSCs promote neural differentiation and neuroprotection in ischemic brains, at least in part by modulating the Notch signaling pathway. These findings highlight hUCMSCs as a promising therapeutic strategy for IS.