Mitofusin-2 mediated mitochondrial Ca 2+ uptake 1/2 induced liver injury in rat remote ischemic perconditioning liver transplantation and alpha mouse liver-12 hypoxia cell line models

World J Gastroenterol. 2017 Oct 14;23(38):6995-7008. doi: 10.3748/wjg.v23.i38.6995.

Abstract

Aim: To investigate the protective mechanism of mitofusin-2 (Mfn2) in rat remote ischemic perconditioning (RIC) models and revalidate it in alpha mouse liver-12 (AML-12) hypoxia cell lines.

Methods: Sprague-Dawley rats were divided into three groups (n = 6 each): sham, orthotopic liver transplantation and RIC. After operation, blood samples were collected to test alanine aminotransferase and aspartate aminotransferase. The liver lobes were harvested for histopathological examination, western blotting (WB) and quantitative real-time (qRT)-PCR. AML-12 cell lines were then subjected to normal culture, anoxic incubator tank culture (hypoxia) and anoxic incubator tank culture with Mfn2 knockdown (hypoxia + Si), and data of qRT-PCR, WB, mitochondrial membrane potential (ΔΨm), apoptosis, endoplasmic reticulum Ca2+ concentrations and mitochondrial Ca2+ concentrations were collected.

Results: Both sham and normal culture groups showed no injury during the experiment. The RIC group showed amelioration of liver function compared with the orthotopic liver transplantation group (P < 0.05). qRT-PCR and WB confirmed that Mfn2-mitochondrial Ca2+ uptake 1/2 (MICUs) axis was changed (P < 0.005). In AML-12 cell lines, compared with the hypoxia group, the hypoxia + Si group attenuated the collapse of ΔΨm and apoptosis (P < 0.005). The endoplasmic reticulum Ca2+ decrease and mitochondrial Ca2+ overloading observed in the hypoxia group were also attenuated in the hypoxia + Si group (P < 0.005). Finally, qRT-PCR and WB confirmed the Mfn2-MICUs axis change in all the groups (P < 0.005).

Conclusion: Mfn2 participates in liver injury in rat RIC models and AML-12 hypoxia cell lines by regulating the MICUs pathway.

Keywords: Ca2+; Ischemia-reperfusion injury; Mitochondrial Ca2+ uniporter; Mitofusin-2; Remote ischemic per-conditioning.

MeSH terms

  • Animals
  • Apoptosis
  • Calcium / metabolism
  • Calcium Channels / metabolism*
  • Cell Line
  • Endoplasmic Reticulum / metabolism
  • GTP Phosphohydrolases / metabolism*
  • Hypoxia / metabolism
  • Ischemic Preconditioning*
  • Liver Transplantation*
  • Male
  • Membrane Proteins / metabolism*
  • Mice
  • Mitochondria / metabolism
  • Mitochondrial Proteins / metabolism*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Calcium Channels
  • Membrane Proteins
  • Mitochondrial Proteins
  • mitochondrial calcium uniporter
  • GTP Phosphohydrolases
  • Mfn2 protein, mouse
  • Mfn2 protein, rat
  • Calcium