H2S and homocysteine control a novel feedback regulation of cystathionine beta synthase and cystathionine gamma lyase in cardiomyocytes

Paras Kumar Mishra,Shyam Sundar Nandi

doi:10.1038/s41598-017-03776-9

Paras Kumar Mishra, Shyam Sundar Nandi

Open Access

https://doi.org/10.1038/s41598-017-03776-9

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Journal: Scientific Reports	Publication Date: Jun 16, 2017
Citations: 55	License type: open-access

Affiliation: University of Nebraska Medical Center

Abstract

Hydrogen sulfide (H2S), a cardioprotective gas, is endogenously produced from homocysteine by cystathionine beta synthase (CBS) and cystathionine gamma lyase (CSE) enzymes. However, effect of H2S or homocysteine on CBS and CSE expression, and cross-talk between CBS and CSE are unclear. We hypothesize that homocysteine and H2S regulate CBS and CSE expressions in a dose dependent manner in cardiomyocytes, and CBS deficiency induces cardiac CSE expression. To test the hypothesis, we treated murine atrial HL1 cardiomyocytes with increasing doses of homocysteine or Na2S/GYY4137, a H2S donor, and measured the levels of CBS and CSE. We found that homocysteine upregulates CSE but downregulates CBS whereas Na2S/GYY4137 downregulates CSE but upregulates CBS in a dose-dependent manner. Moreover, the Na2S-treatment downregulates specificity protein-1 (SP1), an inducer for CSE, and upregulates miR-133a that targets SP1 and inhibits cardiomyocytes hypertrophy. Conversely, in the homocysteine-treated cardiomyocytes, CBS and miR-133a were downregulated and hypertrophy was induced. In vivo studies using CBS+/−, a model for hyperhomocysteinemia, and sibling CBS+/+ control mice revealed that deficiency of CBS upregulates cardiac CSE, plausibly by inducing SP1. In conclusion, we revealed a novel mechanism for H2S-mediated regulation of homocysteine metabolism in cardiomyocytes, and a negative feedback regulation between CBS and CSE in the heart.

Highlights

In the homocysteine-treated cardiomyocytes, cystathionine beta-synthase (CBS) and miR-133a were downregulated and hypertrophy was induced
50 μM and 75 μM doses of Na2S increased the mRNA and protein levels of CBS but decreases the respective levels of cystathionine gamma lyase (CSE) (Fig. 1C,D), suggesting that higher doses of Na2S induces CBS but inhibits CSE in cardiomyocytes. This trend was not maintained above 75 μM dose and at 100 μM dose Na2S did not change the levels of CBS and CSE (Fig. 1C,D)
We observed that GYY4137 upregulated CBS at higher doses (25 μM and 50 μM) but downregulated CSE at higher doses (50 μM and 75 μM) (Fig. 1E), reinforcing that H2S has an opposite effect on CBS and CSE expressions in cardiomyocytes

Summary

Introduction

In the homocysteine-treated cardiomyocytes, CBS and miR-133a were downregulated and hypertrophy was induced. Hcy level is decreased in clinical trials by folic acid treatment, which remethylate Hcy to methionine Another pathway to reduce Hcy level is transsulfuration of Hcy to hydrogen sulfide (H2S), where cystathionine beta-synthase (CBS) and cystathionine gamma lyase (CSE) enzymes play crucial roles[8]. Na2S-mediated reduction of hypertrophy in HHcy cardiomyocytes indicates that reduced H2S production in HHcy cardiomyocytes may be a major cause for hypertrophy[17], it is unclear whether Hcy or H2S regulates miR-133a levels in a dose-dependent manner. We used HL1 cardiomyocytes cell line, and CBS+/− (a model for HHcy) and sibling CBS+/+ mice to uncover the dose-dependent effects of Hcy or H2S on the levels of CBS and CSE in cardiomyocytes, and to investigate the feedback regulation between CBS and CSE in the heart

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