Microtubular stability affects pVHL-mediated regulation of HIF-1alpha via the p38/MAPK pathway in hypoxic cardiomyocytes

• Published in: PloS one Vol. 7; no. 4; p. e35017
• Main Authors: Teng, Miao, Jiang, Xu-pin, Zhang, Qiong, Zhang, Jia-ping, Zhang, Dong-xia, Liang, Guang-ping, Huang, Yue-sheng
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 10.04.2012; Public Library of Science (PLoS)
• Subjects: Animals; Apoptosis; Biology; Cardiomyocytes; Cell Hypoxia - physiology; Cells, Cultured; Colchicine; Depolymerization; Down-Regulation; Expression vectors; Glycolysis; Heart cells; Heart diseases; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit - genetics; Hypoxia-Inducible Factor 1, alpha Subunit - metabolism; Hypoxia-inducible factor 1a; Hypoxia-inducible factors; Infection; Kinases; Ligases; MAP kinase; Medicine; Microtubule-associated protein 4; Microtubule-Associated Proteins - genetics; Microtubule-Associated Proteins - metabolism; Microtubules - genetics; Microtubules - metabolism; Myocytes, Cardiac - metabolism; Neoplasia; Nitric oxide; p38 Mitogen-Activated Protein Kinases - genetics; p38 Mitogen-Activated Protein Kinases - metabolism; Paclitaxel; Phosphorylation; Plasmids; Rats; Rats, Sprague-Dawley; Regulatory mechanisms (biology); Rodents; Signal Transduction; siRNA; Transfection; Tubulin - metabolism; Tumor suppressor genes; Ubiquitin; Ubiquitin-protein ligase; Ubiquitin-Protein Ligases - genetics; Ubiquitin-Protein Ligases - metabolism; Up-Regulation; VHL protein; Von Hippel-Lindau Tumor Suppressor Protein - genetics; Von Hippel-Lindau Tumor Suppressor Protein - metabolism
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0035017

Our previous research found that structural changes of the microtubule network influence glycolysis in cardiomyocytes by regulating the hypoxia-inducible factor (HIF)-1α during the early stages of hypoxia. However, little is known about the underlying regulatory mechanism of the changes of HIF-1α caused by microtubule network alternation. The von Hippel-Lindau tumor suppressor protein (pVHL), as a ubiquitin ligase, is best understood as a negative regulator of HIF-1α. In primary rat cardiomyocytes and H9c2 cardiac cells, microtubule-stabilization was achieved by pretreating with paclitaxel or transfection of microtubule-associated protein 4 (MAP4) overexpression plasmids and microtubule-depolymerization was achieved by pretreating with colchicine or transfection of MAP4 siRNA before hypoxia treatment. Recombinant adenovirus vectors for overexpressing pVHL or silencing of pVHL expression were constructed and transfected in primary rat cardiomyocytes and H9c2 cells. With different microtubule-stabilizing and -depolymerizing treaments, we demonstrated that the protein levels of HIF-1α were down-regulated through overexpression of pVHL and were up-regulated through knockdown of pVHL in hypoxic cardiomyocytes. Importantly, microtubular structure breakdown activated p38/MAPK pathway, accompanied with the upregulation of pVHL. In coincidence, we found that SB203580, a p38/MAPK inhibitor decreased pVHL while MKK6 (Glu) overexpression increased pVHL in the microtubule network altered-hypoxic cardiomyocytes and H9c2 cells. This study suggests that pVHL plays an important role in the regulation of HIF-1α caused by the changes of microtubular structure and the p38/MAPK pathway participates in the process of pVHL change following microtubule network alteration in hypoxic cardiomyocytes.