Counteracting diabetes-induced adipose tissue derived-stromal cell senescence

Abstract

Adipose tissue stromal cells (ADSCs) are prone to functional decline and senescence during metabolic disturbances. In diabetes mellitus (DM), the pathogenic microenvironment induces oxidative stress causing ADSCs to senesce. The senescence associated secretory phenotype (SASP) in turn drives disease progression. The pathogenesis of DM is thus both a cause and consequence of senescence. Therapeutically preventing the onset of senescence in ADSCs may play a significant role in preventing disease progression and directly impact the onset of comorbidities. The purpose of this study was to establish an in vitro model that mimic the DM micro-environment to use as a screening tool to assess the therapeutic efficacy of preventative and restorative agents. Exposing ADSCs (<passage 10) to a combination of high glucose, advanced glycation end products (AGE-BSA) and TNFα in culture for a period of 3 days induced senescence in 70 ± 4 % of cells (β-galactosidase assay). This coincided with increased ROS production, DNA damage (yH2Ax foci) and excessive release of SASP factors (IFNγ, TNFα, IL1β, IL8, IL6). Pretreatment of ADSCs as well as early intervention using either Metformin (50 μg/mL) or ascorbic acid 2 phosphate (AAP 0.6 mM) could prevent the onset of premature senescence. The expression of genes related to cell cycle (p21cip1, p16INK4A), apoptosis (p53), inflammation (TNFα, IL6, PTX3, IL10) and adipogenesis (PPARγ, UCP3) was assessed, with AAP pretreatment significantly reducing PTX3 expression. Although this study only investigated the early stages following senescence induction (3 days), subsequent studies could employ this model for longer duration and gain insight into premature senescence and the functional decline of ADSCs within the diabetic context, whilst limiting the use of animals.