Fig. 8: Association of DNA double-strand breaks (DSB) in PTECs with macrophage activation in human kidney biopsy samples from patients diagnosed with diabetic nephropathy (DN) or minor glomerular abnormalities (MGA).

A (Left) Representative photomicrographs of IF double staining of γH2AX (green)/AQP1 (red) in the kidney cortex of patients with DN (a) or MGA (b). Scale bar, 50 µm. (right) Quantification of the immunolabeled double-positive area. B (left) Representative photomicrographs of immunohistochemical staining with anti-CD11b or anti-CD11c antibodies in the kidney cortex of patients diagnosed with DN (a) or MGA (b). Scale bar, 50 µm. (right) Correlation between the γH2AX-positive area and the CD11b- or CD11c-positive area. γH2AX-, CD11b- and CD11c-positive areas were counted per field of view. Scale bar, 50 µm. C (a) Correlation between the extent of DNA damage in PTECs using the DNA damage in the SGLT2 gene and DNA methylation at the CpG site cg22012530 in the TSS1500 region. b Correlation between DNA methylation at the CpG site cg22012530 in the TSS1500 region and the hepatic steatosis index (HSI). D Graphical abstract of the study. DNA DSBs in PTECs cause not only metabolic alterations in the kidney but also DNA methylation in blood cells, including reduced DNA methylation at KLF9-binding motifs, such as GSDMD, which triggers the expansion of activated Ly6C^hi Ccr2⁺ monocytes in blood. The activated monocytes subsequently trigger systemic metabolic disturbances associated with macrophage activation. Created in BioRender. https://BioRender.com/rrfwed6. In A and B, n = 5 samples in each group. In C, n = 12 samples in each group. The clinical data are presented in Supplementary Table 1 and 2, respectively. The data are presented as the means ± SEMs. **p < 0.01 vs. the control. Source data are provided as a Source Data file.