Inhibition of autophagy promoted high glucose/ROS-mediated apoptosis in ADSCs

Increased apoptosis in adipose tissue-derived stem cells (ADSCs) limits their application in treating diabetes complications. Autophagy is a molecular process that allows cells to degrade and recover damaged macromolecules, and closely interacts with apoptosis. The aim of the present study was to investigate the potential role of autophagy in ADSC apoptosis induced by high glucose.

Human ADSCs were cultured in normal or high-glucose medium for 6 h, 12 h, or 24 h. The effects of high glucose on ADSC autophagy, reactive oxygen species (ROS) production, and apoptosis were evaluated. The impact of autophagy on ROS production and apoptosis was explored by treatment with rapamycin or 3-methyladenine (3-MA). The c-jun kinase (JNK) signaling pathway was investigated by pharmacological disruption of SP600125.

ADSCs subjected to high glucose stress showed an obvious induction of autophagy and apoptosis and a significant increase in intracellular ROS levels. The JNK signaling pathway was confirmed to be involved in high glucose-induced autophagy. Pre-treatment with SP600125 or N-acetylcysteine reversed the effects of high glucose on the JNK signaling pathway and autophagy-related proteins. Pretreatment of ADSCs with 3-MA under high glucose stress induced a further increase in ROS levels compared to those of high glucose-treated cells. Furthermore, ADSCs pretreated with 3-MA under high glucose stress showed a marked increase in apoptosis compared with that of the cells treated with high glucose. Conversely, pre-treatment with rapamycin inhibited the apoptosis of ADSCs.

Taken together, our data suggest that autophagy may play a protective role in high glucose-induced apoptosis in ADSCs. ROS/JNK signaling is essential in upregulating high glucose-induced autophagy. This study provides new insights into the molecular mechanism of autophagy involved in high glucose-induced apoptosis in ADSCs.