Role of macrophages in liver cirrhosis: fibrogenesis and resolution

Apolipoprotein H-based prognostic risk correlates with liver lipid metabolism disorder in patients with HBV-related hepatocellular carcinoma

Background

/Aim: Chronic hepatitis B patients often develop concomitant fatty liver disease, which is associated with increased risk of liver cirrhosis and hepatocarcinoma. Our previous studies have shown that apolipoprotein H (APOH) levels are gradually decreased in patients with chronic HBV infection at different stages of disease progression, and APOH deficiency disrupted hepatic lipid metabolism and caused fatty liver. We focus on the relationship between APOH and hepatocellular carcinoma (HCC) in the context of chronic HBV infection.

Methods and results

APOH was downregulated at the transcriptional level in HBV-related HCC patients from open-source human liver transcriptome databases, and relatively high expression of APOH might be a favourable prognostic marker in HCC. APOH downregulation was positively associated with tumour grade and HCC subtypes. The analysis result of CHCC-HBV database showed that APOH-associated differential expression genes (DEGs) enriched in lipid metabolic pathways and downregulated APOH correlated with macrophage, neutrophil and CD8 T cell infiltration levels. Next, in vitro experiments were performed and APOH gene was silenced in HepG2.2.15 cells, an HBV producing human HCC cells. Further transcriptomic assay and analysis revealed the DEGs were enriched in cholesterol metabolism. The subsequent RT-qPCR experiments identified that CYP7A1 expression was higher upregulated in APOH silencing HepG2.2.15 cells than vehicle control cells (p < 0.05). Finally, demographic data of patients with HBV-related HCC were enrolled, and serum APOH levels were analysed using ELISA. Serum APOH levels were significantly lower in patients with HCC than in healthy controls (p < 0.05), and positively correlated with triglyceride level in healthy controls (p < 0.05). In HBV-HCC patients, serum APOH levels were positively correlated with albumin levels and negatively correlated with alkaline phosphatase (ALP), total bilirubin, and INR levels (p < 0.05).

Conclusion

APOH downregulation disrupted liver lipid metabolism to potentially affect the overall survival in patients with HBV-related HCC.

The role of hepatic microenvironment in hepatic fibrosis development

AIM

Fibrosis is a common pathological feature of most types of chronic liver injuries. There is no specific treatment for liver fibrosis at present. The liver microenvironment, which fosters the survival and activity of liver cells, plays an important role in maintaining the normal structure and physiological function of the liver. The aim of this review is to deeply understand the role of the liver microenvironment in the dynamic and complicated development of liver fibrosis.

METHODS

After searching in Elsevier ScienceDirect, PubMed and Web of Science databases using 'liver fibrosis' and 'microenvironment' as keywords, studies related to microenvironment in liver fibrosis was compiled and examined.

RESULTS

The homeostasis of the liver microenvironment is disrupted during the development of liver fibrosis, affecting liver cell function, causing various types of cell reactions, and changing the cell-cell and cell-matrix interactions, eventually affecting fibrosis formation.

CONCLUSION

Liver microenvironment may be important for identifying potential therapeutic targets, and restoring microenvironment homeostasis may be an important strategy for promoting the reversal of liver fibrosis.KEY MESSAGESThe homeostasis of the liver microenvironment is disrupted in liver fibrosis;A pro-fibrotic microenvironment is formed during the development of liver fibrosis;Restoring microenvironment homeostasis may be an important strategy for promoting the reversal of liver fibrosis.

Ectodysplasin-A mRNA in exosomes released from activated hepatic stellate cells stimulates macrophage response

INTRODUCTION

The interaction between activated hepatic stellate cells (aHSCs) and macrophages is central to liver fibrosis development. The cargo contained within aHSC exosomes (aHSC-EXOs) and how aHSC-EXOs affect macrophage function is poorly understood.

METHODS

RNA from aHSC-EXOs was separated into small (<200-basepairs) and large (≥200-basepairs) RNA species, transfected into macrophages, and macrophage IL-6 and TNFα mRNA expression and protein secretion measured. Next generation sequencing was performed on EXOs from rat quiescent and aHSCs and human aHSCs. aHSCs were transfected with siRNA against ectodysplasin-A (EDA), EXOs collected, and their effect on macrophage function analyzed. Human cirrhotic liver was analyzed for EDA mRNA expression and compared to non-tumor liver (NTL).

RESULTS

Transfection with large RNA from aHSC-EXOs stimulated macrophage IL-6 and TNFα mRNA expression and protein secretion. EDA mRNA was highly expressed in aHSCs and transfection of aHSCs with EDA-siRNA decreased aHSC-EXO EDA mRNA and blunted the effect of aHSC-EXOs on macrophage function (IL-6/TNFα expression and macrophage migration). Human cirrhotic liver exhibited high EDA mRNA compared to NTL.

CONCLUSIONS

HSC activation leads to altered EXO mRNA/miRNA profiles with aHSC-EXOs mRNAs exerting a dominant role in altering macrophage function. Ectodysplasin-A mRNA is an important component in aHSC-EXOs in regulating macrophage function.