Protective functions of myricetin in LPS-induced cardiomyocytes H9c2 cells injury by regulation of MALAT1

Eur J Med Res. 2019 Apr 26;24(1):20. doi: 10.1186/s40001-019-0378-5.

Abstract

Background: Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a crucial mediator in response to inflammation. Myricetin protects cardiomyocytes against inflammatory injury. However, it's still unexplored whether myricetin exerted anti-inflammatory properties via MALAT1. The purpose of our study was to validate the cardio-protective function of myricetin against myocarditis and its underlying mechanism in vitro.

Methods: H9c2 cells were pre-incubated with myricetin before stimulation with lipopolysaccharide (LPS). Enforced silence of MALAT1 was achieved by transducing short hairpin (sh)-MALAT1 into H9c2 cells. Next, cell viability and apoptotic cells were detected with cell counting kit-8 (CCK-8) and Annexin V-fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) apoptosis detection kit, respectively. Western blot assay was conducted to examine apoptosis-relative proteins, pro-inflammatory factors, and signaling regulators. Quantitative real-time PCR (qRT-PCR) was performed to quantify pro-inflammatory factors and MALAT1 at mRNA levels. Enzyme-linked immune sorbent assay (ELISA) was employed to determine protein concentration of pro-inflammatory factors.

Results: Myricetin ameliorated LPS-elicited reduction of cell viability, augment of apoptosis, and overexpression of monocyte chemo-attractant protein-1 (MCP-1) and interleukin-6 (IL-6) in H9c2 cells. Meanwhile, phosphorylation of p65 and inhibitor of nuclear factor kappa B alpha (IκBα) were suppressed. Besides, myricetin enhanced the expression of MALAT1 which was originally down-regulated by LPS. However, the protective effects of myricetin against LPS-caused inflammatory lesions were abrogated in MALAT1-deficiency cells, with the restored phosphorylation of p65 and IκBα.

Conclusion: Myricetin possessed an anti-inflammatory function against LPS-induced lesions in cardiomyocytes. Mechanically, myricetin up-regulated MALAT1, blocked LPS-evoked activation of nuclear factor-κB (NF-κB) inflammatory pathway, and, finally, exerted cardio-protective effects.

Keywords: Anti-inflammation; MALAT1; Myricetin; NF-κB.

MeSH terms

  • Animals
  • Cardiotonic Agents / pharmacology*
  • Cell Line
  • Flavonoids / chemistry
  • Flavonoids / pharmacology*
  • Inflammation / pathology
  • Inflammation Mediators / metabolism
  • Lipopolysaccharides
  • Myocytes, Cardiac / drug effects
  • Myocytes, Cardiac / metabolism*
  • Myocytes, Cardiac / pathology*
  • NF-kappa B / metabolism
  • RNA, Long Noncoding / genetics
  • RNA, Long Noncoding / metabolism*
  • Rats
  • Signal Transduction / drug effects
  • Up-Regulation / drug effects
  • Up-Regulation / genetics

Substances

  • Cardiotonic Agents
  • Flavonoids
  • Inflammation Mediators
  • Lipopolysaccharides
  • MALAT1 long noncoding RNA, rat
  • NF-kappa B
  • RNA, Long Noncoding
  • myricetin