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Abstract: TH-PO089

Inhibition of H3K4 Trimethylation Attenuates Renal Senescence in Mice with Ischemic Reperfusion Injury

Session Information

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Shimoda, Hironori, Hiroshima University Hospital, Hiroshima, Japan
  • Doi, Shigehiro, Hiroshima University Hospital, Hiroshima, Japan
  • Nakashima, Ayumu, Hiroshima University Hospital, Hiroshima, Japan
  • Masaki, Takao, Hiroshima University Hospital, Hiroshima, Japan
Background

Renal senescence is induced by not only aging, but also various stimuli, and plays important roles in the development of renal inflammation and fibrosis. Recently, accumulation of p16INK4a-positive cells in the kidney has been considered a molecular feature of renal senescence, which is regulated by Mixed-lineage leukemia 1 (MLL1)/WD-40 repeat protein 5 (WDR5)-mediated histone 3 lysine 4 trimethylation (H3K4me3). In this study, we investigated whether MLL1/WDR5 complex inhibitor MM-102 attenuates renal senescence together with renal inflammation and fibrosis in ischemic reperfusion injury (IRI) mice and cultured renal fibroblasts.

Methods

Male C57BL/6 mice were subjected to IRI (renal pedicle was clamped for 30 minutes), and administered MM-102 every 24 hours for 7 days postoperatively. Expression of MLL1, WDR5, H3K4me3, and p16INK4a was examined by western blotting and immunohistochemistry. Senescence-associated β-galactosidase (SA-β-gal) staining was performed as a senescence marker. Renal fibrosis was examined by the expression of transforming growth factor (TGF)-β1, α-smooth muscle actin (αSMA), and collagens. The effect of MM-102 on inflammation was investigated by the expression of nuclear factor-κB (NF-κB), interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor α (TNFα), and CD11b. For the in vitro study, TGF-β1-stimulated normal renal fibroblasts with and without MM-102 preincubation were examined for expression of MLL1, WDR5, H3K4me3, and p16INK4a. Chromatin immunoprecipitation assays were performed to clarify the status of p16INK4a gene promoter as an H3K4me3-enrichment region.

Results

MM-102 suppressed expression of p16INK4a and β-gal in IRI mice, accompanied by decreased expression of MLL1 and WDR5 as well as H3K4me3. MM-102 also attenuated renal fibrosis and inflammation in the kidneys of IRI mice. In the in vitro study, TGF-β1 induced expression of MLL1, WDR5, H3K4me3 and p16INK4a. Finally, the p16INK4a promoter was revealed to be an H3K4me3 site in renal fibroblasts.

Conclusion

The MLL1/WDR5 inhibitor MM-102 ameliorates IRI-induced renal senescence together with renal fibrosis and inflammation through a reduction in H3K4me3.

Funding

  • Government Support - Non-U.S.