Dapagliflozin attenuates nicotine-induced apoptosis by targeting the ASK1/p38/JNK apoptotic pathway in HK-2 cells

Objective Cigarette smoking accelerates kidney disease progression. Emerging evidence suggests that dapagliflozin (DAPA) exerts protective effects against various kidney injuries. This study aimed to investigate the effects of DAPA on nicotine (NIC)-induced apoptosis in human kidney proximal tubular epithelial (HK-2) cells. Methods HK-2 cells were treated with NIC, DAPA or selective mitogen-activated protein kinase (MAPK) inhibitors (SP600125 and SB203580). Cell viability, apoptotic cell death and reactive oxygen species (ROS), namely intracellular ROS and MitoSOX, were assessed using a CCK-8 assay and flow cytometry. The concentrations of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were determined by enzyme-linked immunosorbent assay. Protein expression levels related to mitochondrial function, endoplasmic reticulum (ER) stress and the MAPK signalling pathway were analysed by immunoblotting. Results Dapagliflozin and MAPK inhibitors significantly attenuated NIC-induced apoptosis and improved HK-2 cell viability, as evidenced by increased Bcl-2 expression and decreased Bax and Caspase-3 expression. Apoptosis attenuation was closely associated with the suppression of p-ASK1/p-JNK/p-p38 MAPKs and p-MEK3/p-MEK4 activation. Dapagliflozin and MAPK attenuations regulate the expression of oxidant and antioxidant proteins, reducing intracellular ROS and MitoSOX overproduction and thereby alleviating mitochondrial dysfunction and ER stress. Both agents also significantly reduced pro-inflammatory cytokine levels, including TNF-α and IL-1β. Conclusions These findings suggest that DAPA protects HK-2 cells from NIC-induced apoptosis by modulating the ASK1/p38/JNK MAPK signalling pathway, reducing oxidative stress and alleviating inflammation.