Effects And Mechanisms Of Adipose-derived Mesenchymal Stem Cells And Their Exosomes On Inflammatory Cells In Adipocytes And Type 2 Diabetic Rats

Background Type 2 diabetes mellitus(T2D)is a metabolic disease characterized by insulin resistance,relative insulin-insuffiency which can cause abnormal glucose,lipid and protein metabolism disorders.Long-time exposed to hyperglycemia can cause dysfunction of macrovascular complication such as CAD,stroke,and peripheral vascular disease.It’s the main cause of type 2 diabetes patients disability or death.At present,the clinical commonly used hypoglycemic drug therapy can prevent and delay the complications of T2D by controling blood glucose.However,T2D as a chronic metabolic disease is still lack of clinical cure.Mesenchymal stem/stromal cells(MSCs)treatment is an emerging cell therapy for diabetes and related complications.MSCs are a group of adult stem cells that have the capacity of self-renewing and multi lineage differentiation.They can be differentiated into several lineages including osteoblasts,adipocytes and chondrocytes.They are also known for their immunoregulatory abilities which have important clinical applications.More and more researches present MSCs secretory factors(cytokines,miRNA,exosomes,microvesicle)play the key role in treatment.In vivo and in vitro researches have shown MSCs can promote macrophage-induced polarization of M2 and anti-inflammatory effects by secreting anti-inflammatory cytokines(including TGF-β,VEGF,HFG,TSG6,IL-10,etc.),thereby improving myocardial infarction,acute lung injury,skin damage repair and insulin resistance.Exosomes composed of of proteins,lipids,and miRNA/mRNA/DNAs could facilitate the direct intercellular transfer between cells.Also,there are studies explain that exosomes can eliminate hyperglycemia and improve endothelia cell function.At present,the mainly used MSCs are derived from umbilical cord and bone marrow and the preventive effects are obviously.However,the effects of adipose tissue derived MSC as an invention for diabetes mellitus is unclear.Compared to other MSCs,AMSC are more leveraged as a cell source for diabetic intervention as these are endowed with large number of bioactive mediator like leptin,adiponectin,and visfatin,which are known to regulated gluceose homeostasis.Whether AMSCs have the similar effect of treatment of diabetes mellitus is still urgent researched.Objective 1.To explore the effect of exosome derived from AMSC on expression of adipokines and cytokines in inflammatory adipocytes.2.To explore the effects ofAMSC and their exosomes on blood glucose homeostasis,insulin resistance,adiponectin and inflammatory factor expression in T2D rat model and the underlying molecular mechanisms.Method First,we isolated AMSCs from subcutaneous adipose tissue.And induced the AMSC to mature adipocytes.Exosomes were harvested from AMSCs.mRNA expression and secretion of adiponectin,leptin and inflammation-associated cytokines in exosomes-treated inflammatory mature adipocytes were analysed by RT-PCR and ELISA.Secondary,the effect of AMSC and exosomes on glucose homeostasis and insulin sensitivity was evaluated in vivo rat T2D model.Adiponectin and inflammatory cytokines was also evaluated by Elisa test.Results In this study,we found that AMSC derived exosomes can increased inflammatory mature adipocyte leptin and IL-10 mRNA expression.In the vivo study,exosomes could decrease the FBG of T2D rats to some extent.But,both AMSC and exosomes could not improve T2D glucose tolerance as well as insulin resistance.Both AMSC and exosomes could decrease the TNF-a and IL-6 serum level,but there was no significant difference.