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Updated: Aug 27, 2025
Comparative Proteomic Analysis of Whole Kidney, Medulla, and Cortical Tubules in Diabetic Pathogenesis of Kidney Injury in Mice
Published on: May 2, 2025
Proximal tubular epithelia-specific transcriptomics of diabetic mice treated with dapagliflozin
Noriko Uehara-Watanabe1, Natsuko Okuno-Ozeki1, Itaru Nakamura1
1Department of Nephrology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
Abstract:
Based on recent clinical trials using sodium-glucose co-transporter 2 inhibitor (SGLT2i) demonstrating the significant improvement of outcomes of diabetic kidney disease (DKD), the paradigm shift from "glomerulocentric" to "tubule centric" pathophysiology in DKD progression has been highlighted. Several responsible mechanisms for renoprotective effects by SGLT2i have been proposed recently, but the changes in proximal tubule-specific gene expression by SGLT2i in diabetic mice have not been elucidated. We report the analysis of the proximal tubular-specific pathway, demonstrating the downregulation of oxidative phosphorylation in dapagliflozin-treated db/db mice, a type 2 diabetic model. After 8-week treatment of dapagliflozin for db/db mice having a proximal tubule-specific tdTomato reporter, tdTomato-positive cells were isolated by FACS. Pathway analysis of RNA sequencing of isolated tubular epithelia revealed that oxidative phosphorylation was downregulated in dapagliflozin-treated mice. However, depletion of renal tissue ATP content in db/db mice was ameliorated by dapagliflozin administration. Pimonidazole staining demonstrated renal cortical tissue hypoxia in db/db mice, which was improved by dapagliflozin administration. This study suggests that dapagliflozin can ameliorate the excessive oxygen and ATP consumption, and subsequent tissue hypoxia in the diabetic kidney, which may explain, in part, the responsible mechanisms of the renoprotective effects of dapagliflozin.
Insights
Sodium-glucose co-transporter 2 inhibitors (SGLT2i) like dapagliflozin improve diabetic kidney disease (DKD) outcomes. This study reveals SGLT2i reduces excessive oxygen and ATP consumption, mitigating hypoxia in diabetic kidneys.
Area of Science:
- Nephrology
- Diabetology
- Molecular Biology
Background:
- Recent clinical trials highlight SGLT2 inhibitors' efficacy in diabetic kidney disease (DKD).
- The understanding of DKD pathophysiology is shifting towards a tubule-centric view.
- Mechanisms behind SGLT2 inhibitor renoprotection require further elucidation, particularly regarding proximal tubule gene expression.
Purpose of the Study:
- To investigate the impact of dapagliflozin on proximal tubule-specific gene expression in a mouse model of type 2 diabetes.
- To explore the effects of dapagliflozin on cellular energy metabolism and tissue oxygenation in the diabetic kidney.
Main Methods:
- Utilized 8-week dapagliflozin treatment in db/db mice with a proximal tubule-specific tdTomato reporter.
- Isolated tdTomato-positive proximal tubular cells via FACS for RNA sequencing.
- Performed pathway analysis on RNA sequencing data and assessed renal ATP content and tissue hypoxia using pimonidazole staining.
Main Results:
- Dapagliflozin treatment downregulated oxidative phosphorylation in proximal tubular cells of diabetic mice.
- Renal tissue ATP depletion was ameliorated by dapagliflozin administration.
- Dapagliflozin improved renal cortical tissue hypoxia observed in diabetic mice.
Conclusions:
- Dapagliflozin may exert renoprotective effects by reducing excessive oxygen and ATP consumption in the diabetic kidney.
- The observed reduction in oxidative phosphorylation and amelioration of hypoxia contribute to the understanding of SGLT2 inhibitor mechanisms in DKD.
