Jian Wang1, Xin Fu2, Kai Yang3, Qian Jiang2, Yuqin Chen2, Jing Jia2, Xin Duan4, Elizabeth W Wang5, Jianxing He2, Pixin Ran2, Nanshan Zhong2, Gregg L Semenza6, Wenju Lu1. 1. State Key Laboratory of Respiratory Disease, The 1st Affiliated Hospital of Guangzhou Medical University, Guangzhou, 151 Yanjiang Road, Guangzhou, Guangdong 510120, China Division of Pulmonary & Critical Care Medicine, Johns Hopkins University, Baltimore, MD 21224, USA wlu92@yahoo.com jwang31@jhmi.edu. 2. State Key Laboratory of Respiratory Disease, The 1st Affiliated Hospital of Guangzhou Medical University, Guangzhou, 151 Yanjiang Road, Guangzhou, Guangdong 510120, China. 3. State Key Laboratory of Respiratory Disease, The 1st Affiliated Hospital of Guangzhou Medical University, Guangzhou, 151 Yanjiang Road, Guangzhou, Guangdong 510120, China Division of Pulmonary & Critical Care Medicine, Johns Hopkins University, Baltimore, MD 21224, USA. 4. Department of Cardiology, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China. 5. Geisinger Medical Center, Danville, PA 17822, USA. 6. Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD 21224, USA.
Abstract
AIMS: Previously we demonstrated that both hypoxia inducible factor-1 (HIF-1) and bone morphogenetic protein-4 (BMP4) up-regulate transient receptor potential canonical (TRPC) 1 and TRPC6, resulting in increased basal intracellular Ca(2+) concentration ([Ca(2+)]i) in pulmonary arterial smooth muscle cells (PASMCs), driving development of chronic hypoxia (CH)-induced pulmonary hypertension (CHPH). This study aims to determine whether HIF-1 regulates BMP4, and whether BMP4 mediates TRPC and basal [Ca(2+)]i increases in hypoxic PASMCs. METHODS AND RESULTS: The level of BMP4 mature protein was increased for ∼183% in distal pulmonary arterial smooth muscle (PA) from CH (10% O2 for 21 days; CH) exposed rats, and 143% in PASMCs cultured under prolonged hypoxia (4% O2 for 60 h). In rat PASMCs, HIF-1α overexpression up-regulated, whereas HIF-1α knockdown under hypoxia decreased BMP4 expression; site-mutation identified two functional HIF-1-binding sites in Bmp4 gene promoter; noggin or BMP4 siRNA treatment blocked hypoxia-induced increases of TRPC1 and TRPC6 expression and basal [Ca(2+)]i. Likewise, in mice, exposure to CH increased BMP4 expression in distal PA for ∼80%, which was absent in HIF-1α heterozygous mutant mice. Comparing with wild-type littermates, BMP4 heterozygous mutant mice exposed to CH displayed lower BMP4 and TRPC levels in PA, decreased basal [Ca(2+)]i in PASMCs, and attenuated CHPH. In human PASMCs, HIF-1α knockdown attenuated hypoxia-induced BMP4 expression and knockdown of either HIF-1α or BMP4 abolished hypoxia-induced TRPC expression and basal [Ca(2+)]i. CONCLUSIONS: BMP4 acts downstream of HIF-1 and mediates hypoxia-induced up-regulation of TRPC, leading to increased basal [Ca(2+)]i in PASMCs, promoting CHPH pathogenesis. Published on behalf of the European Society of Cardiology. All rights reserved.
AIMS: Previously we demonstrated that both hypoxia inducible factor-1 (HIF-1) and bone morphogenetic protein-4 (BMP4) up-regulate transient receptor potential canonical (TRPC) 1 and TRPC6, resulting in increased basal intracellular Ca(2+) concentration ([Ca(2+)]i) in pulmonary arterial smooth muscle cells (PASMCs), driving development of chronic hypoxia (CH)-induced pulmonary hypertension (CHPH). This study aims to determine whether HIF-1 regulates BMP4, and whether BMP4 mediates TRPC and basal [Ca(2+)]i increases in hypoxic PASMCs. METHODS AND RESULTS: The level of BMP4 mature protein was increased for ∼183% in distal pulmonary arterial smooth muscle (PA) from CH (10% O2 for 21 days; CH) exposed rats, and 143% in PASMCs cultured under prolonged hypoxia (4% O2 for 60 h). In ratPASMCs, HIF-1α overexpression up-regulated, whereas HIF-1α knockdown under hypoxia decreased BMP4 expression; site-mutation identified two functional HIF-1-binding sites in Bmp4 gene promoter; noggin or BMP4 siRNA treatment blocked hypoxia-induced increases of TRPC1 and TRPC6 expression and basal [Ca(2+)]i. Likewise, in mice, exposure to CH increased BMP4 expression in distal PA for ∼80%, which was absent in HIF-1α heterozygous mutant mice. Comparing with wild-type littermates, BMP4 heterozygous mutant mice exposed to CH displayed lower BMP4 and TRPC levels in PA, decreased basal [Ca(2+)]i in PASMCs, and attenuated CHPH. In humanPASMCs, HIF-1α knockdown attenuated hypoxia-induced BMP4 expression and knockdown of either HIF-1α or BMP4 abolished hypoxia-induced TRPC expression and basal [Ca(2+)]i. CONCLUSIONS:BMP4 acts downstream of HIF-1 and mediates hypoxia-induced up-regulation of TRPC, leading to increased basal [Ca(2+)]i in PASMCs, promoting CHPH pathogenesis. Published on behalf of the European Society of Cardiology. All rights reserved.
Authors: M Yasuo; S Mizuno; D Kraskauskas; H J Bogaard; R Natarajan; C D Cool; M Zamora; N F Voelkel Journal: Eur Respir J Date: 2010-06-18 Impact factor: 16.671
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