Dapagliflozin exerts anti-apoptotic effects by mitigating macrophage polarization via modulation of the phosphoinositide 3-kinase/protein kinase B signaling pathway.

Abstract

Background: Macrophages are central to the orchestration of immune responses, inflammatory processes, and the pathogenesis of diabetic complications. The dynamic polarization of macrophages into M1 and M2 phenotypes critically modulates inflammation and contributes to the progression of diabetic nephropathy. Sodium-glucose cotransporter 2 inhibitors such as dapagliflozin, which are acclaimed for their efficacy in diabetes management, may influence macrophage polarization, thereby ameliorating diabetic nephropathy. This investigation delves into these mechanistic pathways, aiming to elucidate novel therapeutic strategies for diabetes.

Aim: To investigate the inhibitory effect of dapagliflozin on macrophage M1 polarization and apoptosis and to explore its mechanism of action.

Methods: We established a murine model of type 2 diabetes mellitus and harvested peritoneal macrophages following treatment with dapagliflozin. Concurrently, the human monocyte cell line cells were used for in vitro studies. Macrophage viability was assessed in a cell counting kit 8 assay, whereas apoptosis was evaluated by Annexin V/propidium iodide staining. Protein expression was examined through western blotting, and the expression levels of macrophage M1 surface markers, inflammatory cytokines, and apoptotic factors were quantified using flow cytometry, enzyme linked immunosorbent assay, and quantitative real-time polymerase chain reaction analyses.

Results: Dapagliflozin attenuated M1 macrophage polarization and mitigated apoptosis in the abdominal macrophages of diabetic mice, evidenced by the downregulation of proapoptotic genes (Caspase 3), inflammatory cytokines [interleukin (IL)-6, tumor necrosis factor-α, and IL-1β], and M1 surface markers (inducible nitric oxide synthase, and cluster of differentiation 86), as well as the upregulation of the antiapoptotic gene BCL2. Moreover, dapagliflozin suppressed the expression of proteins associated with the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway (PI3K, AKT, phosphorylated protein kinase B). These observations were corroborated in vitro, where we found that the modulatory effects of dapagliflozin were abrogated by 740Y-P, an activator of the PI3K/AKT signaling pathway.

Conclusion: Dapagliflozin attenuates the polarization of macrophages toward the M1 phenotype, thereby mitigating inflammation and promoting macrophage apoptosis. These effects are likely mediated through the inhibition of the PI3K/AKT signaling pathway.