SLC5A2-SRC-ERK/STAT3 signaling network in proximal tubule S1 cells mediates the renoprotective effects of dapagliflozin in obese mice.

Obesity-related kidney disease (ORKD) has a complex pathogenesis, and current therapeutic strategies have significant limitations. Although sodium-glucose cotransporter 2 inhibitors (SGLT2i) exhibit remarkable renoprotective effects, their direct cellular targets and underlying molecular mechanisms remain unclear. In this study, we systematically elucidated the mechanism of action of dapagliflozin (DAPA) by integrating a high-fat diet (HFD)-induced obese mouse model, single-nucleus RNA sequencing (snRNA-seq), high-dimensional gene co-expression network analysis (hdWGCNA), in vitro functional validation, and urinary metabolomics. We identified the S1 segment of the proximal tubule (PT-S1) as the core cell type mediating the response to obesity-induced stress and drug-mediated renoprotection. Under obese conditions, the expression of sodium-glucose cotransporter 2 (SGLT2), encoded by the solute carrier family 5 member 2 (SLC5A2) gene, was aberrantly upregulated in this cell subset. Acting as a central signaling hub, SLC5A2 activates SRC kinase, which in turn triggers the phosphorylation of the downstream extracellular regulated protein kinases 1/2 (ERK1/2) and signal transducer and activator of transcription 3 (STAT3) signaling cascades, thus forming a synergistically amplified injury network that ultimately leads to impaired renal intercellular communication and systemic metabolic imbalance. By directly targeting and inhibiting SLC5A2, DAPA blocked the aberrant activation of this cooperative network at its source, restored the expression of key paracrine signaling molecules (VEGFA, vascular endothelial growth factor A; COL4A4, collagen type IV alpha 4 chain), remodeled the renal tissue microenvironment, and reversed the dysregulation of systemic oxidative stress-related metabolites and the aldosterone signaling pathway. At single-cell resolution, this study delineated a novel mechanism underlying the multidimensional renoprotective effects of SGLT2i, mediated through interference with the SLC5A2-SRC-ERK/oxidative stress-STAT3 cooperative signaling network, thereby laying a new theoretical foundation for the clinical application of SGLT2i in the management of ORKD.