| Objectives: Previous studies have shown that human umbilical cord mesenchymal stem cell exosomes(exosomes derived from human umbilical cord mesenchymal stem cells,hucMSC-ex)can promote Fibroblast-to-Myofibroblast Differentiation in Inflammatory Environments and Benefit Cardioprotective Effects.What components in the exosomes play a key role in this process is the focus of this research.Studies have reported that Galectin-3(Gal-3)plays an important role in the phenotypic transformation of cardiac fibroblasts.This research aims to explore the role and mechanism of Gal-3 derived from human umbilical cord mesenchymal stem cells in promoting the phenotype and functional transformation of cardiac fibroblasts in an inflammatory environment.Methods: Adipogenic and osteogenic differentiation induction experiment,Flow cytometry,Nanosight nanoparticle analyzer and Western blot were used to identify hucMSC and hucMSC-ex.Western blot was used to detect Gal-3 protein expression in hucMSC-ex and RNA interference technology knocked down Gal-3 in hucMSC.In vitro,Lipopolysaccharide(LPS)has been used to induce inflammatory responses.On this basis,hucMSC-ex,negative control-si RNA-hucMSC-ex(NC-ex)and Gal-3-si RNA-hucMSC-ex(si Gal-3-ex)were added in myocardial fibroblasts,respectively.Western blot,Transwell cell migration test,collagen gel contraction test,and q RT-PCR were used to evaluate the effect of Gal-3 derived from hucMSC-ex on cardiac fibroblasts phenotype transformation,cell migration,collagen contraction ability,β-catenin and inflammatory factors.In addition,further investigate were carried out to explore the effect of myocardial fibroblast transformation on the repair of myocardial injury.In vivo,PBS,hucMSC-ex,NC-ex,and si Gal-3-ex were immediately injected into the SD rats’ myocardium that underwent myocardial infarction through permanently ligating the left anterior descending coronary artery.Cardiomyocytes were subjected to hypoxia induction in vitro.Western blot and immunohistochemical staining were used to evaluate the effect of Gal-3 derived from hucMSC-ex on myocardial fibroblast phenotype transformation,inflammatory factor expression and cardiomyocyte apoptosis.Results: HucMSCs were able to differentiate into adipogenic osteoblasts and highly express CD105,CD90 and CD29,but not CD45,CD34 or CD19.HucMSC-ex had a particle size of 30～150nm and expressed exosomal marker proteins CD63,CD81 and TSG-101,but did not express calnexin.In vitro studies have confirmed that Gal-3protein was in the hucMSC-ex and Gal-3 derived from hucMSC-ex promoted the transformation of cardiac fibroblasts into myofibroblasts in an inflammatory environment.After the transformation,the contractile ability was enhanced,the migration ability was weakened,and the expression of anti-inflammatory factors were Increased,the expression of pro-inflammatory factors were decreased,the expression of β-catenin was up-regulated and the expression of apoptosis-related protein was reduced in cardiomyocytes.In vivo,the expression of myofibroblast-related proteins in the infarct area were increased,the expression of anti-inflammatory factors were increased,whereas the expression of pro-inflammatory factors were weakened in the hucMSC-ex injection group.However,this experimental phenomenon was not found in the si-ex injection group.Conclusion: Gal-3 derived from HucMSC-ex can promote the transformation of cardiac fibroblasts into myofibroblasts,and further reduce the expression of pro-inflammatory factors and apoptosis of cardiac myocytes in an inflammatory environment. |
