Hypertonic environment regulates cadherin expression and affects em-bryoid body differentiation / 中国病理生理杂志

ABSTRACT

AIM:Given the uncertain impact of osmotic pressure on embryoid body(EB)differentiation,this study aimed to investigate the effects of increased osmotic pressure on EB differentiation and explore the potential relation-ship between this process and cadherin.METHODS:Polhethylene glycol 300(PEG 300)was used to increase the os-motic pressure of the culture medium used for cultivating EBs under both high osmotic pressure and standard culture condi-tions.The experimental design included a control group,an experimental group(hypertonic group),groups treated with varying concentrations of PEG 300,and an experimental group treated with an inhibitor.Western blot,RT-qPCR,AM/PI staining,CCK-8,and immunocytochemical staining was used to analyze the cell viability and the expression of CDH1 and CDH2 markers of the three germ layers,and pluripotency markers within the EBs.RESULTS:Hypertonicity did not af-fect cell viability.Significant differences were observed in the expression of the cadherin proteins CDH1 and CDH2 in EBs between the experimental and control groups;however,no cleartrend towards an EMT shift was observed.Specifically,CDH2 expression was significantly down-regulated in experimental group,showing a clear correlation with variations in os-motic pressure.Moreover,compared with control group,pluripotency markers in the EBs from experimental group exhibited significantly higher expression levels from the 2nd day to the 5th day.A substantial increase in the expression of mesoder-mal markers was also observed;however,a downward trend was observed for ectodermal markers in experimental group.Intervention using SB431542,which up-regulates CDH2 expression by affecting TGF-β signaling,reversed the expression trend of mesodermal and ectodermal markers in experimental group.CONCLUSION:Elevated osmotic pressure appears to enhance the mesodermal differentiation efficiency in EBs,possibly correlating with CDH1 and CDH2 changes induced by osmotic pressure.Therefore,this study emphasizes the significant role of osmotic pressure in stem cell applications.