The Role Of Notch1 Signaling In Mesenchymal Stem Cells Mediated Alleviation Of Emphysema In CS-exposed Rat Models

Objective: Previous studies have demonstrated that mesenchymal stem cells(MSC)administration has a therapeutic potential in airway inflammation,but has limited effect on the repair of emphysema in smoking rats.Notch1 signaling pathway plays an important role not only in the occurrence,differentiation and maturation of lung epithelial cells,but also plays an important role in stem cell differentiation and function maintenance.Thus,present study has been performed to investigate the following issues:(1)to explore the mechanism of Notch1 regulating proliferation,migration and anti-apoptotic ability of MSC;(2)the mechanism of Notch1 signaling regulating the differentiation of MSC into endothelial cells under cigarette smoking conditions;(3)and the role of Notch1 signaling in mesenchymal stem cells mediated alleviation of emphysema in CS-exposed rat modelMethods:(1)The Notch1 overexpressing MSC(MSC-N1ICD)was constructed by lentivirus-transfection.The proliferation of MSC were detected by Western blot and immunofluorescence in vitro with Cigarette smoke extract(CSE)stimulation;TUNEL and immunohistochemistry to detect the apoptosis of MSC,migration ability of MSC was detected by transwell assay.(2)Overexpression and knockdown of Notch1 signal in MSC were used to detect the regulation of Notch1 on differentiation of MSC into endothelial cells.Western blot,Real time-PCR and immunofluorescence and flow cytometry were used to detect the expression of endothelial cell specific markers.The tubule forming ability was detected by matrigel assay.The effect of MSC-N1 ICD on Notch1 pathway activity and Jagged1 protein expression in MSC was detected by transwell co-culture,and further verified the role of Jagged1 in differentiation of MSC into endothelial cells.MSC was administrated by intratracheal approach to evaluate the repair of emphysema in Cigarette smoke(CS)exposed rat.HE staining of lung tissue was used to detect the severity of emphysema.Apoptosis of lung tissue was detected by Western blot and immunohistochemistry.The retention of mesenchymal stem cells in the lung was detected by In-Vivo Optical Imaging system.Result:(1)Overexpression of Notch1 increases the proliferation,migration and anti-apoptotic ability of MSC under cigarette smoking conditions,and improves the resistance of MSC to CSE cytotoxicity;(2)Notch1 signaling enhances the ability of MSC differentiate into endothelial cells by up-regulating the expression of Jagged1 protein depend on RBP-Jκ,and increases the microvessel density in the lung tissue of CS-exposed rat after MSC administration(3)Notch1 signaling improves the repair of emphysema in CS-exposed rat by up-regulating MSC-mediated inhibiting the apoptosis of lung cells and increasing the retention of MSC in the lung.Conclusion: Notch1 signaling can improve the repair property of MSC by increasing the capacity of proliferation,migration and anti-apoptotic under cigarette smoking condition.Notch1 signaling enhances the ability of MSC to differentiate into endothelial cells by upregulating the Jagged1 protein expression in a paracrine manner,and improve lung tissue microvessel density in CS-exposed rat,as wells as upregulated MSC-mediated inhibiting the apoptosis of alveolar epithelial cells and increasing the retention of MSC in the lung,further promote the repair of emphysema in CS-exposed rat.