Biliverdin reductase/bilirubin mediates the anti-apoptotic effect of hypoxia in pulmonary arterial smooth muscle cells through ERK1/2 pathway.

Abstract

Inhibition of pulmonary arterial smooth muscle cell (PASMC) apoptosis induced by hypoxia plays an important role in pulmonary arterial remodeling leading to aggravate hypoxic pulmonary arterial hypertension. However, the mechanisms of hypoxia acting on PASMC apoptosis remain exclusive. Biliverdin reductase (BVR) has many essential biologic roles in physiological and pathological processes. Nevertheless, it is unclear whether the hypoxia-induced inhibition on PASMC apoptosis is mediated by BVR. In the present work, we found BVR majorly localized in PASMCs and was up-regulated in levels of protein and mRNA by hypoxia. Then we studied the contribution of BVR to anti-apoptotic response of hypoxia in PASMCs. Our results showed that siBVR, blocking generation of bilirubin, reversed the effect of hypoxia on enhancing cell survival and apoptotic protein (Bcl-2, procasepase-9, procasepase-3) expression, preventing nuclear shrinkage, DNA fragmentation and mitochondrial depolarization in starved PASMCs, which were recovered by exogenous bilirubin. Moreover, the inhibitory effect of bilirubin on PASMC apoptosis under hypoxic condition was blocked by the inhibitor of ERK1/2 pathway. Taken together, our data indicate that BVR contributes to the inhibitory process of hypoxia on PASMC apoptosis, which is mediated by bilirubin through ERK1/2 pathway.

• Authors: Shasha Song, Shuang Wang, Jun Ma, Lan Yao, Hao Xing, Lei Zhang, Lin Liao, Daling Zhu
• Journal: Experimental cell research (Exp Cell Res) Vol. 319 Issue 13 Pg. 1973-1987 (Aug 01 2013) ISSN: 1090-2422 [Electronic] United States
• PMID: 23722043 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2013 Elsevier Inc. All rights reserved.

Chemical References

• RNA, Small Interfering
• Oxidoreductases Acting on CH-CH Group Donors
• biliverdin reductase
• Bilirubin

Topics

• Animals
• Apoptosis (drug effects, genetics, physiology)
• Bilirubin (metabolism, physiology)
• Cell Hypoxia (drug effects, genetics, physiology)
• Cell Size (drug effects)
• Cell Survival (drug effects, genetics)
• Cells, Cultured
• MAP Kinase Signaling System (drug effects, genetics, physiology)
• Male
• Muscle, Smooth, Vascular (cytology, drug effects, metabolism, physiology)
• Myocytes, Smooth Muscle (drug effects, metabolism, physiology)
• Oxidoreductases Acting on CH-CH Group Donors (antagonists & inhibitors, genetics, physiology)
• Pulmonary Artery (cytology, drug effects, metabolism, physiology)
• RNA, Small Interfering (pharmacology)
• Rats
• Rats, Wistar