Antioxidants improve the viability of diabetic bone marrow MSCs without rescuing their pro-regenerative secretome function

Bone marrow mesenchymal stem cell (BM-MSC) dysfunction and poor viability are prominent in diabetes and limit their therapeutic efficacy. A proteomic investigation was performed to assess disease associated alterations and the efficacy of antioxidants to rescue cellular function. BM-MSCs were isolated from obese diabetic mice (B6.Cg-Lep^ob/J) cultured in the presence or absence of N-acetylcysteine (NAC) and ascorbic acid-2phosphate (AAP). Label free Liquid Chromatography and Mass Spectrometry (LC-MS) analysis detected 5079 proteins with 251 being differentially expressed between treatment groups. NAC/AAP improved cellular growth/viability post isolation by up-regulating proteins involved in redox status, ATP synthesis, Rho-GTPase signaling and modulated the immunophenotype of BM-MSCs. Despite a single application of the secretome not providing any advantage for wound bed regeneration in full thickness excisional diabetic wounds, the intracellular proteome illustrated the potential mechanisms of action by which NAC/AAP targeted the respiratory chain and modulated the immune phenotype of BM-MSCs. Given these observations, antioxidant supplementation might be more effective as prophylactic strategy to protect MSCs against functional decline instead of using it as a restorative agent and warrants further investigation.