ABSTRACT
The forkhead protein (FoxO) family plays a crucial role in regulating oxidative stress, cell proliferation, and apoptosis. FoxO6, a member of the FoxO family, helps regulate oxidative stress in gastric cancer and hepatocellular carcinoma. However, it is unclear whether FoxO6 participates in the protective effect of isoflurane preconditioning in liver injury caused by oxidative stress in ischemia. In this study, we explored the role and mechanism of FoxO6 in the protective effect of isoflurane preconditioning during hepatocyte injury caused by oxygen-glucose deprivation (OGD). Cells from the human fetal hepatocyte (LO2) line were incubated with 0%, 1%, 2%, 2.5%, 3%, 3.5%, 4%, or 5% isoflurane for 3 h and then exposed to OGD. Data showed that 3% isoflurane preconditioning inhibited FoxO6 expression, caspase-3 activity, and reactive oxygen species production and promoted cell viability. FoxO6 overexpression abolished the effects of 3% isoflurane preconditioning on caspase-3 activity, reactive oxygen species production, and cell viability in these cells. Moreover, FoxO6 regulated nuclear factor erythroid 2-related factor (Nrf2) expression via c-Myc after 3% isoflurane preconditioning and OGD exposure. Thus, isoflurane preconditioning prevented OGD-induced injury in LO2 cells by modulating FoxO6, c-Myc, and Nrf2 signaling.
Subject(s)
Forkhead Transcription Factors/genetics , Isoflurane/pharmacology , NF-E2-Related Factor 2/genetics , Neurons/drug effects , Proto-Oncogene Proteins c-myc/genetics , Apoptosis/drug effects , Cell Hypoxia/drug effects , Gene Expression Regulation/drug effects , Glucose/metabolism , Hepatocytes/drug effects , Humans , Ischemic Preconditioning/methods , Liver/drug effects , Liver/injuries , Liver/metabolism , Liver/pathology , Neurons/metabolism , Oxidative Stress/drug effects , Oxygen/metabolism , Reactive Oxygen Species/metabolism , Signal Transduction/drug effectsABSTRACT
BACKGROUND: We demonstrated growing evidence supports a protective role of chlorogenic acid of rat hepatocytes elicited by two compounds, i.e. thapsigargin and palmitic acid. Nevertheless, little is known about the mechanisms of palmitic acid induced endoplasmic reticulum (ER) stress and cell death. METHODS: The proliferation of primary rat hepatocytes was detected by MTT assay. The expression of GRP78, CHOP and GRP94 was detected by Western blot analyses. Caspase-3 activity was detected by a Caspase-3 substrate kit. Cell apoptosis was detected by Hoechst 33342 staining. RESULTS: We demonstrated that incubation of hepatocytes for 16 h with palmitic acid elevated cell death. Moreover, Western blot analyses demonstrated increased levels of the endoplasmic reticulum stress markers - glucose regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), and glucose regulated protein 94 (GRP94). Chlorogenic acid could inhibit ER stress induced cell death and levels of indicators of ER stress caused by palmitic acid. The effect of thapsigargin, which evokes ER stress were reversed by chlorogenic acid. CONCLUSIONS: Altogether, our data indicate that in primary rat hepatocytes, chlorogenic acid prevents ER stress-mediated apoptosis of palmitic acid.
Subject(s)
Apoptosis/drug effects , Chlorogenic Acid/pharmacology , Heat-Shock Proteins/genetics , Membrane Glycoproteins/genetics , Transcription Factor CHOP/genetics , Animals , Cell Proliferation/drug effects , Endoplasmic Reticulum Stress/drug effects , Gene Expression Regulation/drug effects , Hepatocytes/drug effects , Hepatocytes/metabolism , Palmitic Acid , Primary Cell Culture , Rats , Signal Transduction/drug effects , Thapsigargin/pharmacologyABSTRACT
Hepatic ischemia and reperfusion (I/R) injury is a major cause of liver damage during liver transplantation, resection surgery, shock, and trauma. It has been reported that TXNIP expression was upregulated in a rat model of hepatic I/R injury. However, the role of TXNIP in the hepatic I/R injury is little known. In our study, we investigated the biological role of TXNIP and its potential molecular mechanism in the human hepatic cell line (HL7702â¯cells). Using oxygen-glucose deprivation and reoxygenation (OGD/R) to create a cell model of hepatic I/R injury, we found that the mRNA and protein expression levels of TXNIP were upregulated in HL7702â¯cells exposed to OGD/R. TXNIP overexpression remarkably promoted OGD/R-induced cell apoptosis and lactate dehydrogenase (LDH) release, both of which were significantly decreased by TXNIP knockdown. The production of malondialdehyde (MDA) was also increased by TXNIP overexpression, but was reduced by TXNIP knockdown. Moreover, TXNIP overexpression significantly upregulated the phosphorylation of p38 and JNK, which was remarkably inhibited by TXNIP knockdown. Additionally, p38-specific inhibitor SB203580 abrogated the effect of TXNIP overexpression on OGD/R-induced cell injury. Taken together, these results indicated that TXNIP knockdown alleviated hepatocyte I/R injury through preventing p38/JNK pathway activation. Thus, TXNIP might offer a novel potential therapeutic target for the treatment of hepatic I/R injury.
