Fig 1: SASP derived from senescent cells contributes to renal cell damage. (A and B) KIM‐1 expression and LDH release in young HK‐2 cells treated with different CM‐SASP for 2 days. (C and D) Prostaglandins levels in DN mice with rIL‐33 or αIL‐33. (E) Prostaglandin levels in SASP of senescent HK‐2 cells (n = 3). (F–H) SA‐β‐gal+ cell, KIM‐1 expression, and LDH release in HK‐2 cells treated with COX‐2 inhibitor NS‐398 (10 µM) for 5 days (scale bar: 20 µm). (I and J) KIM‐1 expression and LDH release in young HK‐2 cells treated with different CM‐SASP (Si‐IL‐33 and NS‐398) for 2 days. *p < 0.05, **p < 0.01, ***p < 0.001.
Fig 2: Renal senescence and aging are improved in IL‐33+/− and ST2+/− DN mice and. αIL‐33‐treated WT DN mice. WT mice considered diabetic were intraperitoneally injected with IgG or αIL‐33 twice a week for 12 weeks and maintained with HFD feeding. IL‐33+/− and ST2+/− DN mice were maintained with HFD feeding for 26 weeks. (A) The circulating IL‐33 level was measured by ELISA. (B and C) FBG and renal‐body ratio. (D‐F) Renal function was measured by Scr, BUN, and ACR. (G) Representative images of H&E, PAS staining (scale bar: 20 µm), and transmission electron microscopy (scale bar: 1 µm). (H) The statistics of pathological indicators in the glomeruli included glomerular area, PAS‐positive areas, GBM thickness, and foot process width. (I and J) Renal tubular injury score and KIM‐1 protein level were used to measure renal tubular changes. *p < 0.05, **p < 0.01, ***p < 0.001.
Fig 3: rIL‐33 administration aggravates renal injury in DN mice. Diabetic mice were intraperitoneally injected with PBS or rIL‐33 twice a week for 12 weeks and maintained with HFD feeding. (A) Serum IL‐33 levels were measured by ELISA at the endpoint of the experiment. (B–F) FBG, renal‐body ratio, Scr, BUN, and ACR were assessed. (G) Representative micrographs about DN‐related pathological indicators. (H) The statistics of glomerular area, PAS‐positive area, GBM thickness, and foot process width. (I) Renal tubular injury score based on the area of renal tubular injury in H&E images. (J) Renal lysates were processed for western immunoblot analysis for KIM‐1. (K) Correlation of eGFR, glomerular area, and KIM‐1 expression with IL‐33 level and ST2 level. (L) eQTL analysis between IL‐33 mRNA in whole blood and the SNPs of IL33 nearby region (± 500 kb) using data provided by GTEx. The x‐axis showed the chromosomal positions and the y‐axis showed a −log10 p value; the significance threshold used in our analysis was p < 0.01. (M) OR (95% CI) in PRS associated with DN risk among participants with or without DN from UK biobank. *p < 0.05, **p < 0.01, ***p < 0.001.
Fig 4: Renal injury is exacerbated in IL‐33−/− or ST2−/− DN mice. WT, IL‐33−/−, and ST2−/− mice were continued to be fed for 12 weeks after they were determined to be diabetic. Control mice were continuously fed with ND. (A–E) FBG, renal‐body ratio, Scr, BUN, and ACR were monitored at the end of the experiment. (F) Representative images of kidney tissue stained with H&E and PAS (scale bar: 20 µm). Ultra‐structural changes in glomerular morphology were assessed by transmission electron microscopy (scale bar: 1 µm). (G and H) The glomerular area and PAS‐positive area were assessed in 3 mice with at least 10 glomeruli per mouse. (I and J) GBM thickness and foot process width were calculated in electron microscopic images of at least 5 fields of view per mouse. (K) The renal tubular injury score was estimated by H&E staining. (L) Immunoblot analysis for KIM‐1. *p < 0.05, **p < 0.01, ***p < 0.001.
Fig 5: Mechanism flow chart. Sustained hyperglycemic stimulation leads to an increased production of IL‐33, which in turn accelerates senescence in tubular epithelial cells. The senescent cells then release SASP components, including IL‐33 and prostaglandins, which further amplify cellular senescence and exacerbate renal lesions.
Supplier Page from MedChemExpress for IL-33 Protein, Mouse