Alpha-oxoglutarate inhibits the proliferation of immortalized normal bladder epithelial cells via an epigenetic switch involving ARID1A

Muhammad Shahid,Nicole Gull,Jooeun Bae,Benjamin P Berman,Sungyong You,Austin Yeon,Minjung Kim,Jayoung Kim,Hyun Seok Yoon,Hana Yoon,Eunho Cho

doi:10.1038/s41598-018-22771-2

Abstract

Interstitial cystitis (IC) is a chronic urinary tract disease that is characterized by unpleasant sensations, such as persistent pelvic pain, in the absence of infection or other identifiable causes. We previously performed comprehensive metabolomics profiling of urine samples from IC patients using nuclear magnetic resonance and gas-chromatography/mass spectrometry and found that urinary α-oxoglutarate (α-OG), was significantly elevated. α-OG, a tricarboxylic acid (TCA) cycle intermediate, reportedly functions to suppress the proliferation of immortalized normal human bladder epithelial cells. Here, we identified AT-rich interactive domain 1 A (ARID1A), a key chromatin remodeler, as being hypomethylated and upregulated by α-OG treatment. This was done through EPIC DNA methylation profiling and subsequent biochemical approaches, including quantitative RT-PCR and western blot analyses. Furthermore, we found that α-OG almost completely suppresses ten-eleven translocation (TET) activity, but does not affect DNA methyltransferase (DNMT) activity. Altogether, our studies reveal the potential role of α-OG in epigenetic remodeling through its effects on ARID1A and TET expression in the bladder. This may provide a new possible therapeutic strategy in treating IC.

Highlights

Interstitial cystitis (IC) is a chronic urinary tract disease that is characterized by unpleasant sensations, such as persistent pelvic pain, in the absence of infection or other identifiable causes
We found that levels of p53 and p21 significantly increased while levels of JunB modestly increased in the presence of α-OG (Fig. 1B)
It is still unclear whether these metabolic biomarkers are biologically active in urine and how they contribute to bladder pathogenesis and homeostasis

Summary

Introduction

Interstitial cystitis (IC) is a chronic urinary tract disease that is characterized by unpleasant sensations, such as persistent pelvic pain, in the absence of infection or other identifiable causes. Our studies reveal the potential role of α-OG in epigenetic remodeling through its effects on ARID1A and TET expression in the bladder. This may provide a new possible therapeutic strategy in treating IC. Treatment with α-OG in bladder epithelial cells suppressed cell proliferation and was consistent with previous observations by other groups that found α-OG inhibited cell cycle transitions through the up or downregulation of p21Waf1/Cip[1], p27Kip[1], cyclin D1, and Rb. no functional impacts or mechanisms of urinary α-OG have been proposed in the setting of bladder wall abnormalities or diseases and no correlations have been previously described

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Conclusion