Rapamycin Promotes the Survival and Adipogenesis of Ischemia-Challenged Adipose Derived Stem Cells by Improving Autophagy

Abstract

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.

Mitofusin 2 Exerts a Protective Role in Ischemia Reperfusion Injury Through Increasing Autophagy

“…3a, b). And we examined the influence of rapamycin (a well-documented autophagy inducer) on the number of autophagosomes and autolysosomes [28]. Our results demonstrated that the numbers of yellow puncta (early autophagosomes) were higher in the rapamycin treated group than the control group (2.0±0.5774 vs 6.667±0.8819, P < 0.05 ) (Fig.…”

Ischemia-Like Stress Conditions Stimulate Trophic Activities of Adipose-Derived Stromal/Stem Cells

“…In the present study, the cells were able to maintain their viability for several days despite the complete exhaustion of glucose. This could possibly be due to an enhanced autophagic activity of the cells, as autophagy has been shown to be a survival mechanism for oxygen/glucose-deprived MSCs [ 36 , 37 , 38 ]. A further observation was that those ASCs that survived under the harsh ischemic condition (glucose/oxygen deprivation) were not affected in their adipogenic differentiation capability.…”

Short-Term Rapamycin Preconditioning Diminishes Therapeutic Efficacy of Human Adipose-Derived Stem Cells in a Murine Model of Multiple Sclerosis

“…Previous work suggests that short-term, but not long-term, inhibition of the mammalian target of rapamycin (mTOR) activity intensifies mesenchymal stem cell immunomodulation. In BMSCs, short-term Rapa results in elevated production of immune-modifying factors increased immunosuppression of PBMC or splenocyte proliferation, and protection against apoptosis following exposure to ischemia or oxygen-glucose deprivation [ 28 , 51 ]. In the present study, we examined the effect of short-term mTOR inhibition with Rapamycin on the immunomodulatory capacity of ASCs in the EAE mouse model of MS. Our results demonstrate that control ASCs exhibited significant therapeutic benefits when administered at DPI 20, as indicated by improved clinical scores, modestly better rotarod performance, and increased myelin levels in the lumbar spinal cord compared to vehicle-treated EAE mice.…”

“…The preconditioning of MSCs with Rapa results in substantial improvement of their immunoregulatory function in animal models of graft vs. host disease and cutaneous wound healing [ 23 , 24 ]. Moreover, Rapa exposure has demonstrated an effective reversal of MSC senescence [ 25 , 26 , 27 ], resiliency to apoptosis-inducing stimuli [ 28 ], and robust enrichment of immunomodulatory function [ 29 , 30 , 31 ]. Furthermore, short-term Rapa exposure caused an increase in both cyclooxygenase-2 (COX2) and prostaglandin-E2 (PGE2) in bone marrow-derived mesenchymal stem cells (BMSCs) in vitro [ 30 ].…”