FAM3A mediates PPARγ's protection in liver ischemia-reperfusion injury by activating Akt survival pathway and repressing inflammation and oxidative stress.

Zhenzhen Chen,Junpei Wang,Ji Chen,Bin Geng,Weili Yang,Qinghua Cui,Yuhong Meng,Jichun Yang

doi:10.18632/oncotarget.17805

Abstract

FAM3A is a novel mitochondrial protein, and its biological function remains largely unknown. This study determined the role and mechanism of FAM3A in liver ischemia-reperfusion injury (IRI). In mouse liver after IRI, FAM3A expression was increased. FAM3A-deficient mice exhibited exaggerated liver damage with increased serum levels of AST, ALT, MPO, MDA and oxidative stress when compared with WT mice after liver IRI. FAM3A-deficient mouse livers had a decrease in ATP content, Akt activity and anti-apoptotic protein expression with an increase in apoptotic protein expression, inflammation and oxidative stress when compared WT mouse livers after IRI. Rosiglitazone pretreatment protected against liver IRI in wild type mice but not in FAM3A-deficient mice. In cultured hepatocytes, FAM3A overexpression protected against, whereas FAM3A deficiency exaggerated oxidative stress-induced cell death. FAM3A upregulation or FAM3A overexpression inhibited hypoxia/reoxygenation-induced activation of apoptotic gene and hepatocyte death in P2 receptor-dependent manner. FAM3A deficiency blunted rosiglitazone's beneficial effects on Akt activation and cell survival in cultured hepatocytes. Collectively, FAM3A protects against liver IRI by activating Akt survival pathways, repressing inflammation and attenuating oxidative stress. Moreover, the protective effects of PPARγ agonist(s) on liver IRI are dependent on FAM3A-ATP-Akt pathway.

Highlights

Mouse hepatocytes were treated with water, H2O2 (400μM), H2O2+Rosig for 24h. 1–2×106 cells were trypsinized using EDTA-free trypsin and centrifuged at 1000 rpm
The cells were collected and washed twice in PBS, and labeled with 7-AAD and Annexin V-FITC in binding buffer for 15 min in the dark according to manufacturer's instructions
The isolation of mitochondrial and cytosolic fractions were performed according to the instructions for the Mitochondria/Cytosol Isolation Kit (C1260, Applygen Technologies Inc.). 30mg livers were homogenized in 1.5mL of ice-cold Mito-Cyto Buffer with a Dounce homogenizer

Summary

Introduction

FAM3A mediates PPARγ’s protection in liver ischemiareperfusion injury by activating Akt survival pathway and repressing inflammation and oxidative stress Apoptosis was detected using Annexin V-FITC/7AAD staining. Mouse hepatocytes were treated with water, H2O2 (400μM), H2O2+Rosig for 24h. 1–2×106 cells were trypsinized using EDTA-free trypsin and centrifuged at 1000 rpm. The cells were collected and washed twice in PBS, and labeled with 7-AAD and Annexin V-FITC in binding buffer for 15 min in the dark according to manufacturer's instructions.

Results

Conclusion