Ursolic acid stimulates UCP2 expression and protects H9c2 cells from hypoxia-reoxygenation injury via p38 signaling

J Biosci. 2018 Dec;43(5):857-865.

Abstract

Oxidative stress and apoptosis is involved in hypoxia-reoxygenation (H/R) induced myocardial injury. Increased expression of uncoupling protein 2 (UCP2), a cationic carrier protein, has protective effect against H/R injury. The present study aimed to find candidate drugs for H/R induced cardiac damage by identifying compounds regulating UCP2 expression. Here, among six natural compounds, ursolic acid (UA) had the most significant induction effect on UCP2 expression in H9c2 cells under H/R conditions. Subsequently, we found that UA significantly attenuated cell apoptosis and Caspase 3 activity, but increased nitric oxide (NO) release under H/R conditions. Additionally, UA pretreatment also decreased reactive oxygen species (ROS) production and malondialdehyde (MDA) content, but increased superoxide dismutase (SOD) activity. H/R caused a notable increase in the phosphorylation of p38, which was weakened by UA pretreatment. Moreover, p38 inhibitor (SB203580) showed the similar effects on H/R cells as UA pretreatment, while UCP2 knockdown had the reverse biological effects. More importantly, the effects of UA or p38 inhibitor exposure were partially rescued by UCP2 knockdown. Collectively, our data suggested the functions of UA on UCP2 expression and on the protection of H/Rstimulated H9c2 cells may be attributed to p38 signaling pathway.

MeSH terms

  • Animals
  • Apoptosis / drug effects
  • Caspase 3 / genetics
  • Caspase 3 / metabolism
  • Cell Hypoxia
  • Cell Line
  • Gene Expression Regulation
  • Imidazoles / pharmacology
  • Malondialdehyde / metabolism
  • Myocytes, Cardiac / cytology
  • Myocytes, Cardiac / drug effects*
  • Myocytes, Cardiac / metabolism
  • Nitric Oxide / metabolism
  • Oxidative Stress
  • Phosphorylation / drug effects
  • Pyridines / pharmacology
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Rats
  • Reactive Oxygen Species / metabolism
  • Signal Transduction / drug effects*
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism
  • Triterpenes / pharmacology*
  • Uncoupling Protein 2 / agonists
  • Uncoupling Protein 2 / antagonists & inhibitors
  • Uncoupling Protein 2 / genetics*
  • Uncoupling Protein 2 / metabolism
  • Ursolic Acid
  • p38 Mitogen-Activated Protein Kinases / genetics*
  • p38 Mitogen-Activated Protein Kinases / metabolism

Substances

  • Imidazoles
  • Pyridines
  • RNA, Small Interfering
  • Reactive Oxygen Species
  • Triterpenes
  • Ucp2 protein, rat
  • Uncoupling Protein 2
  • Nitric Oxide
  • Malondialdehyde
  • Superoxide Dismutase
  • p38 Mitogen-Activated Protein Kinases
  • Casp3 protein, rat
  • Caspase 3
  • SB 203580