Identification of MAP3K4 as a novel regulation factor of hepatic lipid metabolism in non-alcoholic fatty liver disease.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a metabolic disorder with abnormal lipid metabolism. The present study was to identify regulatory genes related to lipid droplets (LDs) abnormal accumulation in NAFLD. METHODS: transcriptomic analysis and bioinformatics analysis (GEO database) were used to identify potential genes in abnormal lipid metabolism of NAFLD. A candidate gene MAP3K4 expression were detected by immunohistochemistry staining in NAFLD and controls. RNA interference and immunoblotting were used to verify the roles of MAP3K4 in the formation of hepatic LDs. RESULTS: A total of 134 candidate genes were screened, including 44 up-regulated genes and 90 down-regulated genes. 29 genes in the protein-protein interaction (PPI) were selected as hub genes, including MAP3K4. The expression levels of MAP3K4 were positively correlated with NAFLD activity score (r = 0.702, p = 0.002). Furthermore, we found a positive correlation of MAP3K4 expression with serum total cholesterol (r = 0.564, p = 0.023), uric acid levels (r = 0.520, p = 0.039), and body mass index (r = 0.574, p = 0.020). Downregulation of MAP3K4 decreased LDs accumulation in HepG2 cells and reduced the expression of CGI-58 and Plin-2 by imbibition of JNK and group IVA cytosolic phospholipase A2 (cPLA2) activation. CONCLUSION: The study revealed a number of regulatory genes related to hepatic lipid metabolism of NAFLD, and demonstrated that MAP3K4 played a pivotal role in the hepatic lipogenesis of NAFLD.

Transcriptomic analysis reveals a novel regulatory factor of ECHDC1 involved in lipid metabolism of non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the highest incidence of chronic liver disease worldwide characterized by lipid accumulation in the liver. The full understanding of the lipogenesis of NAFLD is extreme importance. Here, whole-genome transcriptome analysis was performed on liver tissues of NAFLD patients and healthy controls to identify the differentially expressed genes and find new pathways and target genes related to the lipogenesis of NAFLD. Combined with the Gene Expression Omnibus (GEO) database, we found 86 overlapping genes, many of which are related to lipid metabolism of NAFLD. ECHDC1 is one of 86 overlapping genes, and its role in NAFLD has not been reported. The expression of ECHDC1 was significantly increased in liver tissue of patients with NAFLD than that of healthy controls, and oil Red O intensity was positively correlated with the expression levels of ECHDC1. Inhibition of ECHDC1 expression in HepG2 cells by RNAi significantly reduced intracellular lipid droplet number in vitro. In summary, this study analyzed pathogenic factors related to NAFLD at the whole-genome level and demonstrated that ECHDC1 may be involved in the occurrence and development of NAFLD by regulating hepatic lipid metabolism.

Combined Analysis of Expression Profiles in a Mouse Model and Patients Identified BHMT2 as a New Regulator of Lipid Metabolism in Metabolic-Associated Fatty Liver Disease.

Metabolic associated fatty liver disease (MAFLD) is associated with obesity, type 2 diabetes mellitus, and other metabolic syndromes. Farnesoid X receptor (FXR, NR1H4) plays a prominent role in hepatic lipid metabolism. This study combined the expression of liver genes in FXR knockout (KO) mice and MAFLD patients to identify new pathogenic pathways for MAFLD based on genome-wide transcriptional profiling. In addition, the roles of new target genes in the MAFLD pathogenic pathway were also explored. Two groups of differentially expressed genes were obtained from FXR-KO mice and MAFLD patients by transcriptional analysis of liver tissue samples. The similarities and differences between the two groups of differentially expressed genes were analyzed to identify novel pathogenic pathways and target genes. After the integration analysis of differentially expressed genes, we identified 134 overlapping genes, many of which have been reported to play an important role in lipid metabolism. Our unique analysis method of comparing differential gene expression between FXR-KO mice and patients with MAFLD is useful to identify target genes and pathways that may be strongly implicated in the pathogenesis of MAFLD. The overlapping genes with high specificity were screened using the Gene Expression Omnibus (GEO) database. Through comparison and analysis with the GEO database, we determined that BHMT2 and PKLR could be highly correlated with MAFLD. Clinical data analysis and RNA interference testing in vitro confirmed that BHMT2 may a new regulator of lipid metabolism in MAFLD pathogenesis. These results may provide new ideas for understanding the pathogenesis of MAFLD and thus provide new targets for the treatment of MAFLD.

Sequencing of Cell-Free DNA to Monitor Cytomegalovirus Infection After Liver Transplant.

OBJECTIVES: In the present study, we investigated donor-derived cell-free DNA dynamics and assessed the diagnostic efficacy of 2 tests: the sequencing of cytomegalovirus-derived cell-free DNA and the quantitative nucleic acid amplification test in cytomegalovirus infection following liver transplant. MATERIALS AND METHODS: We first examined 6 patients who were identified with active cytomegalovirus DNAemia by both quantitative nucleic acid amp-lification test and next-generation sequencing of cytomegalovirus-derived cell-free DNA and then performed a receiver operating characteristic analysis to evaluate the efficacy of cell-free DNA sequencing and establish a cutoff for this assay. Further validation of the next-generation sequencing method was also performed in 84 liver transplant recipients. The study protocol conformed to the ethical guidelines of the Declaration of Helsinki and the Declaration of Istanbul. RESULTS: In the first 6 patients, there was no significant correlation between the cytomegalovirus infection and donor-derived cell-free DNA. We determined that the levels of cytomegalovirus-derived cell-free DNA sequencing directly correlate with the results of the quantitative nucleic acid amplification test (area under the curve 0.982) and obtained a value of 0.015% as a cutoff for the cell-free DNA sequencing assay. In the validation cohort composed of 84 liver transplant recipients, next-generation sequencing of cell-free DNA revealed the occurrence of cytomegalovirus infection that remains otherwise undetected by the quantitative nucleic acid amplification test. CONCLUSIONS: Cytomegalovirus infections that do not cause direct graft injury (cytomegalovirus-related hepatitis) did not result in elevations of donor-derived cell-free DNA. Next-generation sequencing of cytomegalovirus-derived cell-free DNA provides a potential tool for detection of cytomegalovirus infection that remains undetected by the quantitative nucleic acid amplification test.

Prognostic factors influencing outcome in adult liver transplantation using hypernatremic organ donation after brain death.

BACKGROUND: Hypernatremic donors was regarded as the expanded criteria donors in liver transplantation. The study was to investigate the effects of donor hypernatremia on the outcomes of liver transplantation and identify the prognostic factors possibly contributing to the poor outcomes. METHODS: Donor serum sodium levels before procurement were categorized as normal sodium (< 155 mmol/L), moderate high sodium (155-170 mmol/L), and severe high sodium (≥ 170 mmol/L). Furthermore, we subdivided the 142 hypernatremic donors (≥ 155 mmol/L) into two subgroups: subgroup A, the exposure time of liver grafts from hypernatremia to reperfusion was < 36 h; and subgroup B, the exposure time was ≥ 36 h. The outcomes included initial graft function, survival rates of grafts and recipients, graft loss and early events within the first year following liver transplantation. RESULTS: There were no significant differences in the 1-year survival rates of grafts and recipients, 1-year graft loss rates and early events among the normal, moderate high and severe high sodium groups. However, the overall survival rates of grafts and recipients in subgroup A were significantly higher than those in subgroup B. Cox model showed that the exposure time (HR = 1.117; 95% CI: 1.053-1.186; P < 0.001), cold ischemia time (HR = 1.015; 95% CI: 1.006-1.024; P = 0.001) and MELD (HR = 1.061; 95% CI: 1.003-1.121; P = 0.037) were the important prognostic factors contributing to the poor outcomes of recipients with hypernatremic donors. CONCLUSIONS: The level of donor sodium immediately before organ procurement does not have negative effects on the early outcomes following adult liver transplantation. For hypernatremia liver donors, minimization of the exposure time from hypernatremia to reperfusion is critical to prevent graft loss.