Vitronectin mediates survival of human WJ-MSCs under inflammatory temperature stress via cell cycle arrest.

Abstract

Due to their anti-inflammatory and immunomodulatory capabilities, mesenchymal stem cells (MSCs) are being widely used in cell-based therapies for the treatment of a wide spectrum of inflammatory disorders. Despite their promises, substantial cell loss post transplantation leads to compromised therapeutic benefits in clinical trials, which remains a challenge to overcome. Inflammatory microenvironment comprises the presence of pro-inflammatory cytokines, elevated temperature, etc., which could hamper MSC viability following transplantation. Thus, identifying the underlying molecular factors controlling survival mechanism under such stress conditions, thereby, improving MSC survival becomes important for optimising MSC-based therapy. Also, since MSCs from different origins have significantly varied biology, choosing the appropriate MSC source could be crucial in determining the fate of transplanted MSCs in stressful milieu. As extracellular matrix (ECM) components can mediate cell survival signals, in the present study, we have evaluated the role of ECM matricellular protein, vitronectin (VTN), in the survival of human umbilical cord-derived Whartons Jelly MSCs (WJ-MSCs) under the condition of inflammatory temperature stress. On exposure to 40{degrees}C, WJ-MSCs underwent cell cycle arrest with no significant change in viability status, along with an induction in VTN expression both at mRNA and protein levels. Interestingly, inhibition of pro-survival signalling pathways, ERK or PI3K, at 40{degrees}C led to further upregulation in VTN expression without any significant impact on viability or cell cycle arrest status. However, on knocking down VTN in WJ-MSCs at 40{degrees}C, decrease in viable population along with reversal of cell cycle arrest were noted. Moreover, inhibition of pro-survival pathways ERK or PI3K, in VTN knocked down WJ-MSCs at 40{degrees}C, led to a dramatic reduction in the viable population accompanied with reversal in cell cycle arrest. Altogether, our findings highlighted the protective role of VTN in mediating survival of WJ-MSCs under inflammatory temperature stress condition, by possibly involving autophagy as an underlying mechanism.