Inflammatory Milieu by Crosstalk between Glomerulus and Proximal Tubular Cells in Type 2 Diabetes Mellitus Kidney Disease.

Background: Due to the limited availability of therapeutic agents for type 2 diabetic kidney disease (T2DKD), there is a need for further knowledge derived from experimental models and innovative techniques. In addressing this issue, single-cell RNA sequencing (scRNA-seq) has been exclusively applied to a genetically modified diabetic kidney disease model, but not to an induced model representing T2DKD. Herein, we analyzed scRNA-seq and other experiments from an induced T2DKD model and validated the results in human-derived biospecimens.

Methods: The model was induced by combining a high-fat diet with streptozotocin to simulate induced T2DKD. scRNA-seq, histological, and flow cytometric analyses were conducted, and the results were compared with control mice. The findings were then applied to human T2DKD kidneys.

Results: Biochemical and histological analyses unveiled early-stage T2DKD features, such as hyperfiltration, increased proteinuria, glomerulomegaly, and interstitial fibrosis. scRNA-seq identified that proximal tubules secreted a variety of chemokines, potentially in response to crosstalk with glomeruli. Notably, C-X-C motif chemokine 12 (CXCL12) emerged as a key player in potentially promoting T-cell recruitment. Flow cytometry substantiated T-cell infiltration into the kidney of the T2DKD model. This finding was further corroborated in human biopsied kidney tissues, showing a correlation between elevated CXCL12 levels and T2DKD progression.

Conclusion: The induced T2DKD model highlights the pivotal role of CXCL12-mediated T-cell infiltration, stemming from the crosstalk between proximal tubules and glomeruli. This data serves as a foundation for future studies, promising a therapeutic target for T2DKD.