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Abstract: FR-OR33

Multi-Omic Analysis Identifies a New Class of Proximal Tubular Cell With Metabolic Alterations in Diabetic Kidney Disease

Session Information

Category: Diabetic Kidney Disease

  • 601 Diabetic Kidney Disease: Basic

Authors

  • Maekawa, Hiroshi, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Zhou, Yalu, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Fain, Margaret E., Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Kaminski, Dorian, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Chandel, Navdeep S., Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Quaggin, Susan E., Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
Background

Therapeutic inhibition of the sodium glucose cotransporter 2 (SGLT2) protects the kidney although underlying mechanisms are incompletely known. We tested the hypothesis that cell-specific metabolic pathways activated by SGLT2 inhibition in diabetic kidney disease (DKD) underly benefits.

Methods

Kidneys from 10-week-old male Sglt2 mutant (MT) and wildtype (WT) mice, fed with normal or high fat diet (HFD) for eight or eighteen weeks, were analyzed. Changes in body weight, food intake, insulin and glucose tolerance were determined. Single cell RNA sequence (scRNA seq) analysis was performed on libraries prepared from whole kidneys. Metabolomic analysis of renal cortex was conducted by Metabolon, Inc. Human proximal tubular cells (HK-2), were exposed to 50 mM of D-glucose with/without 1uM of Methionine Adenosyltransferase 2A inhibitor (MAT2Ai) and treated with SGLT2 siRNA or S-Adenosyl methionine (SAM) for 48hr.

Results

HFD-induced obesity was similar in both MT and WT while compensatory hyperphagia was observed in MT. Glucose intolerance occurred in mice fed HFD (WT>MT). Molecular and functional markers of kidney injury including KIM-1, number of apoptotic cells and albuminuria were higher in WT>MT. Analysis of scRNAseq data showed emergence of a new class of proximal tubular cells (New-PTC), predominantly found in HFD-fed WT. New-PTC showed increased expression of genes related to epithelial–mesenchymal transition (EMT), apoptosis and inflammation. Pathway enrichment analysis of metabolomic data uncovered differences in WT vs MT renal cortex; metabolites of methionine cycle including SAM were preferentially increased in HFD-fed MT. High glucose treatment of HK-2 recapitulated molecular changes observed in New-PTC of HFD-WT mice, including markers of EMT (elevated fibronectin, reduced E-cadherin) and inflammation (increased IL-6, IL-8, TNF) which could be inhibited by SGLT2 knock down or SAM supplementation, which enhances methionine metabolism. Conversely, an inhibitor of the methionine cycle, MAT2Ai, exacerbated EMT and inflammation.

Conclusion

Multi-omic analysis identified a New-PTC type and an association between methionine cycle pathway and renal-protection in a model of DKD. SGLT2 inhibition suppressed the emergence of this New-PTC, which can be replicated in vitro by modulation of methionine cycle.

Funding

  • NIDDK Support