5-Aminolevulinic acid with sodium ferrous citrate induces autophagy and protects cardiomyocytes from hypoxia-induced cellular injury through MAPK-Nrf-2-HO-1 signaling cascade

Biochem Biophys Res Commun. 2016 Oct 28;479(4):663-669. doi: 10.1016/j.bbrc.2016.09.156. Epub 2016 Sep 29.

Abstract

Background: Hypoxia causes cardiac disease via oxidative stress and mitochondrial dysfunction. 5-Aminolevulinic acid in combination with sodium ferrous citrate (ALA/SFC) has been shown to up-regulate heme oxygenase-1 (HO-1) and decrease macrophage infiltration and renal cell apoptosis in renal ischemia injury mice. However, its underlying mechanism remains largely unknown. The aim of this study was to investigate whether ALA/SFC could protect cardiomyocytes from hypoxia-induced apoptosis by autophagy via HO-1 signaling.

Materials & methods: Murine atrial cardiomyocyte HL-1 cells were pretreated with ALA/SFC and then exposed to hypoxia.

Results: ALA/SFC pretreatment significantly attenuated hypoxia-induced cardiomyocyte apoptosis, reactive oxygen species production, and mitochondrial injury, while it increased cell viability and autophagy levels. HO-1 expression by ALA/SFC was associated with up-regulation and nuclear translocation of Nrf-2, whereas Nrf-2 siRNA dramatically reduced HO-1 expression. ERK1/2, p38, and SAPK/JNK pathways were activated by ALA/SFC and their specific inhibitors significantly reduced ALA/SFC-mediated HO-1 upregulation. Silencing of either Nrf-2 or HO-1and LY294002, inhibitor of autophagy, abolished the protective ability of ALA/AFC against hypoxia-induced injury and reduced ALA/SFC-induced autophagy.

Conclusion: Taken together, our data suggest that ALA/SFC induces autophagy via activation of MAPK/Nrf-2/HO-1 signaling pathway to protect cardiomyocytes from hypoxia-induced apoptosis.

Keywords: ALA; Apoptosis; Autophagy; Cardioprotection; HO-1; Hypoxia; MAPK; Nrf-2.

MeSH terms

  • Aminolevulinic Acid / pharmacology*
  • Animals
  • Apoptosis / drug effects
  • Autophagy / drug effects*
  • Cell Hypoxia / drug effects*
  • Chromones / pharmacology
  • Citric Acid
  • Enzyme Inhibitors / pharmacology
  • Ferrous Compounds / pharmacology*
  • Heme Oxygenase-1 / metabolism
  • Ischemia / prevention & control
  • Kidney / blood supply
  • MAP Kinase Signaling System / drug effects
  • Macrophages / drug effects
  • Mice
  • Mitogen-Activated Protein Kinases
  • Morpholines / pharmacology
  • Myocytes, Cardiac / drug effects*
  • Myocytes, Cardiac / enzymology
  • Oxidative Stress / drug effects
  • Protective Agents / pharmacology
  • RNA, Small Interfering / genetics
  • Reactive Oxygen Species / metabolism
  • Signal Transduction / drug effects
  • Up-Regulation

Substances

  • Chromones
  • Enzyme Inhibitors
  • Ferrous Compounds
  • Morpholines
  • Protective Agents
  • RNA, Small Interfering
  • Reactive Oxygen Species
  • Citric Acid
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
  • ferrous citrate
  • Aminolevulinic Acid
  • Heme Oxygenase-1
  • Mitogen-Activated Protein Kinases