Role Of Human Umbilical Cord Derived Mesenchymal Stem Cells And Their Exosome In Hyperglycemia Injury And Chronic Inflammation Adipocytes

BackgroundInsulin resistance is one essential character of type 2 diabetes mellitus(T2DM),which can be induced by glucotoxicity and adipose chronic inflammation.Combination treatments of glucotoxicity,chronic inflammation and many other risk factors minic complicated interaction in vivo better than single treatments.In addition,3T3-L1 cell lines are major pre-adipocytes for recent studies of insulin resistance,few reports concerns for human adipocytes and their hyperglycemia injury.Mesenchymal stem cells(MSCs)are non-hematopoietic stem cells with multi-lineage differentiation ability.MSCs ameliorate T2DM and the complications by their immunoregulatory and healing abilities.But homing and in vivo differentiation remain unsolved for MSCs.Thus,cells-free therapy is of great importance.Exosomes derived from MSCs contains abundant molecules to mediate crosstalks between cells and minic biological function of MSCs.Human umbilical cord derived MSCs(hUC-MSCs)are least influenced by donors in compared with bone marrow and adipose derived MSCs.But the role of hUC-MSCs and their exosomes in insulin resistance of human adipocytes is unclear.Objective1.Comparation of the character and function of hUC-MSCs and human adipose derived MSCs(hAMSCs).2.Comparation of adipogenesis in hAMSCs and 3T3-L1 cells.To determine the stable insulin resistance model induced by glucotoxicity and TNF-a among hAMSCs and 3T3-L1 cells.3.To explore the effects of hUC-MSCs and their exosomes on insulin resistance and to figure out the underlying mechanisms.MethodFirst,we isolated MSCs from subcutaneous adipose tissue and umbilical cords.We compared osteogenesis and adipogenesis as well as immunophenotype between hAMSCs and hUC-MSCs.Exosomes were harvested from conditioned medium of hUC-MSCs and were identified by transmission electron microscope and exosome specific antibody expression.Second,insulin resistance is induced by glucotoxicity and TNF-a in mature adipocytes in both hAMSCs and 3T3-L1 cells.Insulin stimulated glucose uptake is measured among inflammation group,glucotoxicity group,combination of inflammation and glucotoxicity group,control group of normal glucose and groups after exosome treatment.Cytokines and adipokines expression is also determined in all groups.ResultsIn our study,hAMSCs presented better adipogenesis and osteogenesis than hUC-MSCs.Rosiglitazone was one effective inducer for 3T3-L1 adipogenesis.Mature adipocytes induced by hAMSCs presented more stable insulin resistance phenotypes than 3T3-L1 cell lines.Exosomes significantly increased insulin stimulated glucose uptake in inflammatory and hyperglycemia injury adipocytes.The mechanisms might relate to up-regulation of adiponectin and sirtuin-1 in the meantime down-regulation of leptin expression.