Rapamycin Promotes the Survival and Adipogenesis of Ischemia-Challenged Adipose Derived Stem Cells by Improving Autophagy.
BACKGROUND/AIMS
Ischemia is one of the main causes of the high rate of absorption of transplanted autologous fat. Autophagy allows cells to survive by providing energy under starvation. Rapamycin has been found to play a role in promoting autophagy. In this study, we investigated whether rapamycin participates in the survival and adipogenesis of ischemia-challenged adipose-derived stem cells (ADSCs) by regulating autophagy.


METHODS
Before the cells were exposed to oxygen-glucose deprivation (OGD), a simulated ischemic microenvironment, the level of autophagy was reduced or increased by lentiviral transfection with short hairpin RNA targeting microtubule-associated protein 1-light chain 3 gene (shRNA-LC3) or treatment with rapamycin, respectively. The level of autophagy was assessed by western blotting, transmission electron microscopythen the apoptosis ratio was determined through terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) and flow cytometry. Adipogenesis was further evaluated by oil red O staining and the expressions level of some specific proteins for adipocytes.


RESULTS
shRNA-LC3 and rapamycin treatment effectively decreased and improved the level of autophagy in cells with or without OGD challenge, respectively. In addition, autophagy inhibition increased the apoptosis rate and activated caspase-3 expression level in response to OGD, and these were markedly inhibited by rapamycin preconditioning. During adipogenesis, autophagy inhibition decreased not only oil droplet accumulation but also lipoprotein lipase (LPL) and peroxisome proliferator-activated receptor gamma (PPARγ) expression in cells with or without OGD challenge. However, autophagy promotion by rapamycin increased oil droplet accumulation and LPL and PPARγ expression.


CONCLUSIONS
Rapamycin may promote the survival and adipogenesis of ischemia-challenged ADSCs by upregulating autophagy.
['Li|Chichi|C|', 'Ye|Lechi|L|', 'Yang|Li|L|', 'Yu|Xiaofang|X|', 'He|Yucang|Y|', 'Chen|Zhuojie|Z|', 'Li|Liqun|L|', 'Zhang|Dan|D|']
D050156:Adipogenesis D000273:Adipose Tissue D017209:Apoptosis D001343:Autophagy D053148:Caspase 3 D015687:Cell Hypoxia D002460:Cell Line D002470:Cell Survival D005947:Glucose D006801:Humans D007511:Ischemia D046529:Microscopy, Electron, Transmission D008869:Microtubule-Associated Proteins D047495:PPAR gamma D034622:RNA Interference D034741:RNA, Small Interfering D016601:RNA-Binding Proteins D020123:Sirolimus D013234:Stem Cells D014162:Transfection
Rapamycin Adipogenesis Autophagy Ischemia Adipose-derived stem cells