ABSTRACT
Nonalcoholic fatty liver disease (NAFLD) has become a worldwide epidemic. A large and growing unmet therapeutic need has inspired numerous studies in the field. Integrating the published genomic data available in the Gene Expression Omnibus (GEO) with NAFLD samples from rodents, we discovered that interferon regulatory factor 6 (IRF6) is significantly downregulated in high-fat diet (HFD)-induced fatty liver. In the current study, we identified IRF6 in hepatocytes as a protective factor in liver steatosis (LS). During HFD challenge, hepatic Irf6 was suppressed by promoter hypermethylation. Severity of HFD-induced LS was exacerbated in hepatocyte-specific Irf6 knockout mice, whereas hepatocyte-specific transgenic mice overexpressing Irf6 (IRF6-HTG) exhibited alleviated steatosis and metabolic disorder in response to HFD feeding. Mechanistic studies in vitro demonstrated that hepatocyte IRF6 directly binds to the promoter of the peroxisome proliferator-activated receptor γ (PPARγ) gene and subsequently halts the transcription of Pparγ and its target genes (e.g., genes that regulate lipogenesis and lipid acid uptake) under physiological conditions. Conclusion: Irf6 is downregulated by promoter hypermethylation upon metabolic stimulus exposure, which fail to inhibit Pparγ and its targets, driving abnormalities of lipid metabolism.
Subject(s)
Gene Expression Regulation , Interferon Regulatory Factors/genetics , Non-alcoholic Fatty Liver Disease/genetics , Non-alcoholic Fatty Liver Disease/pathology , PPAR gamma/genetics , Animals , DNA Methylation/genetics , Diet, High-Fat/adverse effects , Disease Models, Animal , Down-Regulation , Hepatocytes/cytology , Humans , Interferon Regulatory Factors/metabolism , Lipid Metabolism/genetics , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Random Allocation , Sensitivity and SpecificityABSTRACT
OBJECTIVE: To study the function of ZNF300 in the megakaryocytes differentiation and proliferation. METHODS: Public data analysis of ZNF300 expression and megakaryocyte culture were used to reveal the correlation of ZNF300 expression with leukemia and megakaryocyte differetniation; ZNF300 overexpression was mediated by lentiviral or retroviral infection, and the differentiation and proliferation of K562 cells and primary mouse bone marrow cells to magekaryocytes were measured by flow cytometry, MTT assay and colony-forming test; the ZNF300 subcellular localization was tested by separating cytosolic and nuclear extracts combined with Western blotting. The dual-luciferase assay and ChIP-qPCR were used to study ZNF300 target gene. RESULTS: ZNF300 expression upregulation correlated with megakaryoyte differentiation; over-expression of ZNF300 promoted CD41 and CD61 expression, inhibited cell cycle progress, and could reduce colony-forming unit. The ZNF300 locolized in nuclear and regulated C-MYC expression. CONCLUSION: ZNF300 promotes megakaryocyte differentiation.
Subject(s)
Cell Differentiation/drug effects , Megakaryocytes/drug effects , Repressor Proteins/physiology , Animals , Hematopoiesis , Humans , K562 Cells , Mice , Up-RegulationABSTRACT
RATIONALE: Early diagnosis and treatment of tuberculous meningitis saves lives, but current laboratory diagnostic tests lack sensitivity. OBJECTIVES: We investigated whether the detection of intracellular bacteria by a modified Ziehl-Neelsen stain and early secretory antigen target (ESAT)-6 in cerebrospinal fluid leukocytes improves tuberculous meningitis diagnosis. METHODS: Cerebrospinal fluid specimens from patients with suspected tuberculous meningitis were stained by conventional Ziehl-Neelsen stain, a modified Ziehl-Neelsen stain involving cytospin slides with Triton processing, and an ESAT-6 immunocytochemical stain. Acid-fast bacteria and ESAT-6-expressing leukocytes were detected by microscopy. All tests were performed prospectively in a central laboratory by experienced technicians masked to the patients' final diagnosis. MEASUREMENTS AND MAIN RESULTS: Two hundred and eighty patients with suspected tuberculous meningitis were enrolled. Thirty-seven had Mycobacterium tuberculosis cultured from cerebrospinal fluid; 40 had a microbiologically confirmed alternative diagnosis; the rest had probable or possible tuberculous meningitis according to published criteria. Against a clinical diagnostic gold standard the sensitivity of conventional Ziehl-Neelsen stain was 3.3% (95% confidence interval, 1.6-6.7%), compared with 82.9% (95% confidence interval, 77.4-87.3%) for modified Ziehl-Neelsen stain and 75.1% (95% confidence interval, 68.8-80.6%) for ESAT-6 immunostain. Intracellular bacteria were seen in 87.8% of the slides positive by the modified Ziehl-Neelsen stain. The specificity of modified Ziehl-Neelsen and ESAT-6 stain was 85.0% (95% confidence interval, 69.4-93.8%) and 90.0% (95% confidence interval, 75.4-96.7%), respectively. CONCLUSIONS: Enhanced bacterial detection by simple modification of the Ziehl-Neelsen stain and an ESAT-6 intracellular stain improve the laboratory diagnosis of tuberculous meningitis.
