Abstract
SummaryInsulin resistance is an essential characteristic of type 2 diabetes mellitus (T2DM), which can be induced by glucotoxicity and adipose chronic inflammation. Mesenchymal stem cells (MSCs) and their exosomes were reported to ameliorate T2DM and its complications by their immunoregulatory and healing abilities. Exosomes derived from MSCs contain abundant molecules to mediate crosstalk between cells and mimic biological function of MSCs. But the role of exosomes derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) in insulin resistance of human adipocytes is unclear. In this study, exosomes were harvested from the conditioned medium of hUC-MSCs and added to insulin-resistant adipocytes. Insulin-stimulated glucose uptake was measured by glucose oxidase/peroxidase assay. The signal pathway involved in exosome-treated adipocytes was detected by RT-PCR and Western blotting. The biological characteristics and function were compared between hUC-MSCs and human adipose-derived mesenchymal stem cells (hAMSCs). The results showed that hAMSCs had better adipogenic ability than hUC-MSCs. After induction of mature adipocytes by adipogenesis of hAMSC, the model of insulin-resistant adipocytes was successfully established by TNF-α and high glucose intervention. After exosome treatment, the insulin-stimulated glucose uptake was significantly increased. In addition, the effect of exosomes could be stabilized for at least 48 h. Furthermore, the level of leptin was significantly decreased, and the mRNA expression of sirtuin-1 and insulin receptor substrate-1 was significantly upregulated after exosome treatment. In conclusion, exosomes significantly improve insulin sensitivity in insulin-resistant human adipocytes, and the mechanism involves the regulation of adipokines.
Highlights
1.1 Mesenchymal stem cells (MSCs) Culture and Identification human adipose-derived mesenchymal stem cells (hAMSCs) were isolated from discarded adipose tissue from patients who underwent liposuction in the Orthopedic Department of Peking Union Medical College Hospital (PUMCH). hUC-MSCs were isolated from the umbilical cords and placentas of healthy pregnant women at PUMCH
No differences in osteogenesis were observed between hAMSCs and hUCMSCs, but hUC-MSCs were lightly stained after Alizarin Red staining
We demonstrated that exosomes derived from hUC-MSCs improved insulin sensitivity in human adipocytes by upregulating adiponectin and SIRT-1 expression
Summary
All procedures were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2000 Both hAMSCs and hUC-MSCs were cultured in Current Medical Science 41(1):2021 low-glucose Dulbecco’s modified Eagle’s medium (DMEM)/F12 (Corning, USA) containing 10% fetal bovine serum (FBS) (Gibco, USA) and 100 U/mL penicillin/streptomycin at 37°C in a 5% CO2 incubator. MSCs (6th passage) were stained with FITC-conjugated antibodies against CD29, CD31, CD34, CD44, CD73, CD90, CD106 and HLADR (1:500; BD Pharmingen, USA) at room temperature for 30 min in the dark. Cultured cells were lysed with TRIzol reagent (Invitrogen, USA), and RNA was extracted according to the manufacturer’s instructions. Residual glucose in the cell media was determined by measuring the absorbance (A) at 510 nm (Biotek Synergy, USA). The data were presented as the mean ± standard error of the mean and determined by Student’s t test or ANOVA followed by a post SNK q test as appropriate
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