Negative auto-regulation of sulfur dioxide generation in vascular endothelial cells: AAT1 S-sulfenylation

Yunjia Song; Hanlin Peng; Dingfang Bu; Xiang Ding; Fuquan Yang; Zhigang Zhu; Xiaoyu Tian; Lulu Zhang; Xiuli Wang; Chaoshu Tang; Yaqian Huang; Junbao Du; Hongfang Jin

doi:10.1016/j.bbrc.2020.02.040

Negative auto-regulation of sulfur dioxide generation in vascular endothelial cells: AAT1 S-sulfenylation

Biochem Biophys Res Commun. 2020 Feb 19:S0006-291X(20)30306-5. doi: 10.1016/j.bbrc.2020.02.040. Online ahead of print.

Authors

Yunjia Song¹, Hanlin Peng², Dingfang Bu³, Xiang Ding⁴, Fuquan Yang⁴, Zhigang Zhu², Xiaoyu Tian², Lulu Zhang², Xiuli Wang², Chaoshu Tang⁵, Yaqian Huang², Junbao Du⁶, Hongfang Jin⁷

Affiliations

¹ Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China; Research Unit of Clinical Diagnosis and Treatment of Pediatric Syncope and Cardiovascular Diseases, Chinese Academy of Medical Sciences, China.
² Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China.
³ Research Center, Peking University First Hospital, Beijing, 100034, China.
⁴ Key Laboratory of Protein and Peptide Pharmaceuticals & Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
⁵ Department of Physiology and Pathophysiology, Peking University Health Science Centre, Beijing, 100191, China; Key Laboratory of Molecular Cardiology, Ministry of Education, Beijing, 100191, China.
⁶ Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China; Key Laboratory of Molecular Cardiology, Ministry of Education, Beijing, 100191, China.
⁷ Department of Pediatrics, Peking University First Hospital, Beijing, 100034, China. Electronic address: jinhongfang51@126.com.

PMID: 32087961
DOI: 10.1016/j.bbrc.2020.02.040

Abstract

Recently, endogenous sulfur dioxide (SO₂) has been found to exert an important function in the cardiovascular system. However, the regulatory mechanism for SO₂ generation has not been entirely clarified. Hence, we aimed to explore the possible auto-regulation of endogenous SO₂ generation and its mechanisms in vascular endothelial cells. We showed that SO₂ did not affect the protein expression of aspartate aminotransferase 1 (AAT1), a major SO₂ synthesis enzyme, but significantly inhibited AAT activity in primary human umbilical vein endothelial cells (HUVECs) and porcine purified AAT1 protein. An AAT1 enzymatic kinetic study showed that SO₂ reduced the Vmax (1.89 ± 0.10 vs 2.55 ± 0.12, μmol/mg/min, P < 0.05) and increased the Km (35.97 ± 9.54 vs 19.33 ± 1.76 μmol/L, P < 0.05) values. Furthermore, SO₂ induced S-sulfenylation of AAT1 in primary HUVECs and purified AAT1 protein. LC-MS/MS analysis indicated that SO₂ sulfenylated AAT1 at Cys192. Mechanistically, thiol reductant DTT treatment or C192S mutation prevented SO₂-induced AAT1 sulfenylation and the subsequent inhibition of AAT activity in purified AAT1 protein and primary HUVECs. Our findings reveal, for the first time, a mechanism of auto-regulation of SO₂ generation through sulfenylation of AAT1 at Cys192 to suppress AAT activity in vascular endothelial cells. These findings will greatly deepen the understanding of regulatory mechanisms in the cardiovascular homeostasis.

Keywords: Aspartate aminotransferase 1; Cys192; S-sulfenylation; Self-feedback; Sulfur dioxide; Vascular endothelial cells.