SGLT2i-Triggered hyperglycosuria Unveils CDKN2A-Driven distal tubular senescence and EMT, Fueling renal fibrosis.

SGLT2 inhibitors are widely recommended by clinical guidelines for managing diabetes, cardiovascular, and kidney diseases. High glucose induces proximal tubular epithelial cell senescence and epithelial-mesenchymal transition (EMT), promoting renal interstitial fibrosis. However, the impact of SGLT2 inhibitor-induced hyperglucosuria on distal tubular cell biology remains unreported. C57BL/6 or db/db mice were administered empagliflozin via oral gavage for 4 weeks. Tissues were collected post-intervention to assess the immediate effects on distal tubular cell senescence and EMT. After treatment cessation, C57BL/6 and db/db mice were maintained for another 24 and 11 weeks respectively to investigate subsequent effects. In vitro, mouse distal convoluted tubule (mDCT) cells were stimulated with high glucose to verify mechanisms of glucose-induced senescence and EMT. Empagliflozin induced hyperglucosuria that persisted post-cessation. In C57BL/6 mice, immediate effects led to senescence marked by CDKN1A upregulation and EMT in distal tubular cells. Twenty-four weeks post-cessation, these cells exhibited senescence with co-upregulation of CDKN2A and CDKN1A, EMT progression, and renal interstitial fibrosis. In db/db mice, immediate effects did not exacerbate senescence or EMT, but 11 weeks post-cessation aggravated senescence, EMT progression, and renal interstitial fibrosis. In vitro, high glucose promoted reactive oxygen species (ROS) generation, exacerbated DNA damage, and induced mDCT cell senescence and EMT by upregulating CDKN2A. This study first demonstrates that persistent SGLT2 inhibitor-induced hyperglucosuria drives distal tubular cell senescence, EMT, and renal interstitial fibrosis in wild-type and db/db mice, providing foundational evidence for a more comprehensive understanding of these drugs.