Nuclear cardiac myosin light chain 2 modulates NADPH oxidase 2 expression in myocardium: a novel function beyond muscle contraction

Yi Shuai Zhang, Bin Liu, Xiu Ju Luo, Ting Bo Li, Jie Jie Zhang, Jing Jie Peng, Xiao Jie Zhang, Qi Lin Ma, Chang Ping Hu, Yuan Jian Li, Jun Peng, Qingjie Li

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17 Scopus citations

Abstract

Recent studies demonstrated that NADPH oxidase 2 (NOX2) expression in myocardium after ischemia–reperfusion (IR) is significantly upregulated. However, the underlying mechanisms remain unknown. This study aims to determine if nuclear cardiac myosin light chain 2 (MYL2), a well-known regulatory subunit of myosin, functions as a transcription factor to promote NOX2 expression following myocardial IR in a phosphorylation-dependent manner. We examined the phosphorylation status of nuclear MYL2 (p-MYL2) in a rat model of myocardial IR (left main coronary artery subjected to 1 h ligation and 3 h reperfusion) injury, which showed IR injury and upregulated NOX2 expression as expected, accompanied by elevated H<inf>2</inf>O<inf>2</inf> and nuclear p-MYL2 levels; these effects were attenuated by inhibition of myosin light chain kinase (MLCK). Next, we explored the functional relationship of nuclear p-MYL2 with NOX2 expression in H9c2 cell model of hypoxia-reoxygenation (HR) injury. In agreement with our in vivo findings, HR treatment increased apoptosis, NOX2 expression, nuclear p-MYL2 and H<inf>2</inf>O<inf>2</inf> levels, and the increases were ameliorated by inhibition of MLCK or knockdown of MYL2. Finally, molecular biology techniques including co-immunoprecipitation (Co-IP), chromatin immunoprecipitation (ChIP), DNA pull-down and luciferase reporter gene assay were utilized to decipher the molecular mechanisms. We found that nuclear p-MYL2 binds to the consensus sequence AGCTCC in NOX2 gene promoter, interacts with RNA polymerase II and transcription factor IIB to form a transcription preinitiation complex, and thus activates NOX2 gene transcription. Our results demonstrate that nuclear MYL2 plays an important role in IR injury by transcriptionally upregulating NOX2 expression to enhance oxidative stress in a phosphorylation-dependent manner.

Original languageEnglish (US)
JournalBasic Research in Cardiology
Volume110
Issue number4
DOIs
StatePublished - Jul 18 2015

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Keywords

  • Cardiac myosin light chain 2
  • Ischemia
  • NADPH oxidase 2
  • Reperfusion
  • Transcription

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)
  • Physiology

Cite this

Zhang, Y. S., Liu, B., Luo, X. J., Li, T. B., Zhang, J. J., Peng, J. J., Zhang, X. J., Ma, Q. L., Hu, C. P., Li, Y. J., Peng, J., & Li, Q. (2015). Nuclear cardiac myosin light chain 2 modulates NADPH oxidase 2 expression in myocardium: a novel function beyond muscle contraction. Basic Research in Cardiology, 110(4). https://doi.org/10.1007/s00395-015-0494-5