Kidney Week

Abstract: FR-PO456

Inhibition of H3K4 Trimethylation Ameliorates Peritoneal Fibrosis and Senescence

Session Information

• Peritoneal Dialysis: Current Topics
  November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: Dialysis

• 702 Dialysis: Home Dialysis and Peritoneal Dialysis

Authors

• Hara, Daisuke, Hiroshima University Hospital, Hiroshima, Japan

Daisuke Hara,

• Sasaki, Kensuke, Hiroshima University Hospital, Hiroshima, Japan

Kensuke Sasaki,

• Nakashima, Ayumu, Hiroshima University Hospital, Hiroshima, Japan

Ayumu Nakashima,

• Masaki, Takao, Hiroshima University Hospital, Hiroshima, Japan

Takao Masaki,

Background

Senescence is induced by aging as well as various stimuli, resulting in the development of organ inflammation and fibrosis. Recently, the accumulation of p16^INK4a-positive cells is considered as a feature of organ senescence, and p16^INK4a gene expression 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 inhibition ameliorates peritoneal senescence together with peritoneal inflammation and fibrosis in methylglyoxal (MGO) induced peritoneal injury mice and cultured human peritoneal mesothelial cells (HPMCs).

Methods

Peritoneal fibrosis was induced by intraperitoneal injection of MGO in male C57/B6 mice for 3 weeks. MM-102, a MLL1/WDR5 complex inhibitor, was administered subcutaneously at the same time. After 3 weeks of treatment, peritoneal tissues were examined. In an in vitro study, TGF-β1 stimulated HPMCs were examined with or wihout MM-102 preincubation.Chromatin immunoprecipitation (ChIP) assays were performed to clarify the status of p16^INK4a gene promoter as an H3K4me3-enrichment region. Human nonadherent cells were isolated from the effluent of PD patients.

Results

MLL1 was upregulated in the peritoneum of MGO-injected mice, TGF-β1- stimulated HPMCs and human nonadherent cells. MM-102 significantly suppressed p16^INK4a expression, as well as submesothelial zone thickness and cell density in MGO-injected mice. Immunohistochemical staining revealed that MM-102 decreased not only H3K4me3 and p16^INK4a expression, but also peritoneal inflammation and collagen deposition. Moreover, p16^INK4a expression was positively correlated with dialysate-to-plasma (D/P) ratio of creatinine in PD patients. In the in vitro study, MM-102 suppressed TGF-β1-induced upregulation of p16^INK4a, H3K4me3 and fibrotic markers in HPMCs. Finally, ChIP assay revealed that MM-102 decreased the H3K4me3 levels at the promoter of p16^INK4a.

Conclusion

The MLL1/WDR5 inhibitor MM-102 ameliorates peritoneal inflammation and fibrosis through suppression of senescence.