FOXP1 and KLF2 reciprocally regulate checkpoints of stem-like to effector transition in CAR T cells.

In cancer and infections, self-renewing stem-like CD8+ T cells mediate the response of immunotherapies and replenish terminally exhausted T cells and effector-like T cells. However, the programs governing the lineage choice in chimeric antigen receptor (CAR) T cells are unclear. Here, by simultaneously profiling single-cell chromatin accessibility and transcriptome in the same CAR T cells, we identified heterogeneous chromatin states within CD8+ T cell subsets that foreshadowed transcriptional changes and were primed for regulation by distinct transcription factors. Transcription factors that controlled each CD8+ T cell subset were regulated by high numbers of enhancers and positioned as hubs of gene networks. FOXP1, a hub in the stem-like network, promoted expansion and stemness of CAR T cells and limited excessive effector differentiation. In the effector network, KLF2 enhanced effector CD8+ T cell differentiation and prevented terminal exhaustion. Thus, we identified gene networks and hub transcription factors that controlled the differentiation of stem-like CD8+ CAR T cells into effector or exhausted CD8+ CAR T cells.

BACH2 enforces the transcriptional and epigenetic programs of stem-like CD8+ T cells.

During chronic infection and cancer, a self-renewing CD8+ T cell subset maintains long-term immunity and is critical to the effectiveness of immunotherapy. These stem-like CD8+ T cells diverge from other CD8+ subsets early after chronic viral infection. However, pathways guarding stem-like CD8+ T cells against terminal exhaustion remain unclear. Here, we show that the gene encoding transcriptional repressor BACH2 is transcriptionally and epigenetically active in stem-like CD8+ T cells but not terminally exhausted cells early after infection. BACH2 overexpression enforced stem-like cell fate, whereas BACH2 deficiency impaired stem-like CD8+ T cell differentiation. Single-cell transcriptomic and epigenomic approaches revealed that BACH2 established the transcriptional and epigenetic programs of stem-like CD8+ T cells. In addition, BACH2 suppressed the molecular program driving terminal exhaustion through transcriptional repression and epigenetic silencing. Thus, our study reveals a new pathway that enforces commitment to stem-like CD8+ lineage and prevents an alternative terminally exhausted cell fate.

The role of Bach2 in regulating CD8 + T cell development and function.

Bach2 was initially discovered in B cells, where it was revealed to control the transcription involved in cell differentiation. Bach2 is intimately connected to CD8 + T lymphocytes in various differentiation states and subsets according to recent findings. Bach2 can regulate primitive T cells, stimulate the development and differentiation of memory CD8 + T cells, inhibit the differentiation of effector CD8 + T cells, and play a significant role in the exhaustion of CD8 + T cells. The appearance and development of diseases are tightly linked to irregular CD8 + T cell differentiation and function. Accordingly, Bach2 offers novel approaches and possible targets for the clinical treatment of associated disorders based on research on these pathways. Here, we summarize the role of Bach2 in the function and differentiation of CD8 + T cells and its potential clinical applications.

The Inhibition of Bruton Tyrosine Kinase Alleviates Acute Liver Failure via Downregulation of NLRP3 Inflammasome.

There is no effective treatment for acute liver failure (ALF) except for an artificial liver support system (ALSS) and liver transplant. Bruton tyrosine kinase (Btk) plays important immunoregulatory roles in the inflammatory diseases, but its possible function in ALF remains to be characterized. In this study, we detected the phosphorylation level of Btk in ALF mouse liver and analyzed the protective effects of Btk inhibitor on survival rate and liver damage in ALF mouse models. We measured the expression levels of various inflammatory cytokines in the ALF mouse liver and primary human monocytes. In addition, we examined the expression of the NLRP3 inflammasome in mouse models with or without Btk inhibition. Clinically, we observed the dynamic changes of Btk expression in PBMCs of ALSS-treated patients. Our results showed that Btk was upregulated significantly in the experimental ALF mouse models and that Btk inhibition alleviated liver injury and reduced the mortality in these models. The protective effect of Btk inhibitors on ALF mice partially depended on the suppression of NLRP3 inflammasome signaling. Clinical investigations revealed that the dynamic changes of Btk expression in PBMCs could predict the effect of ALSS treatment. Our work shows that Btk inhibition is an effective therapeutic strategy for ALF. Moreover, Btk is a useful indicator to predict the therapeutic effect of ALSS on liver failure, which might have great value in clinical practice.

Decreased miR-17-92 cluster correlates with senescence features, disrupted oxidative homeostasis, and impaired therapeutic efficacy of mesenchymal stem cells.

Aging and replicative cellular senescence are associated with the reduced therapeutic potential of mesenchymal stem cells (MSCs) on a variety of diseases. This study aimed to determine the mechanism in MSC senescence and further explore a modification strategy to reverse senescence-associated cell dysfunction to improve the therapeutic efficacy of MSCs on acute liver failure (ALF). We found that the adipose tissue-derived MSCs from old mice (oAMSCs) exhibited senescence phenotypes and showed reduced therapeutic efficacy in lipopolysaccharide and D-galactosamine-induced ALF, as shown by the increased hepatic necrosis, liver histology activity index scores, serum liver function indicator levels, and inflammatory cytokine levels. The expression of miR-17-92 cluster members, especially miR-17 and miR-20a, was obviously decreased in oAMSCs and replicatively senescent AMSCs, and was consistent with the decreased oncogene c-Myc level during AMSC senescence and may mediate c-Myc stemness addiction. Further experiments revealed that c-Myc-regulated miR-17-92 expression contributed to increased p21 expression and redox system dysregulation during AMSC senescence. Furthermore, modification of AMSCs with the two key miRNAs in the miR-17-92 cluster mentioned above reversed the senescence features of oAMSCs and restored the therapeutic effect of senescent AMSCs on ALF. In conclusion, the cellular miR-17-92 cluster level is correlated with AMSC senescence and can be used both as an index for evaluating and as a modification target for improving the therapeutic potential of AMSCs.NEW & NOTEWORTHY We reported for the first time that c-Myc-regulated miR-17-92 contributed to increased p21 expression and redox system dysregulation during AMSC senescence and was associated with the reduced therapeutic effects of senescent AMSCs on ALF. Moreover, modifying the expression of the miR-17-92 cluster members, especially miR-17 and/or miR-20a, could reverse AMSC senescence. Thus, miR-17-92 cluster can be used both as an index for evaluating and as a modification strategy for improving the therapeutic potential of AMSCs.

A new perspective on mesenchymal stem cell-based therapy for liver diseases: restoring mitochondrial function.

Mesenchymal stem cells (MSCs) have emerged as a promising alternative treatment for liver disease due to their roles in regeneration, fibrosis inhibition, and immunoregulation. Mitochondria are crucial in maintaining hepatocyte integrity and function. Mitochondrial dysfunction, such as impaired synthesis of adenosine triphosphate (ATP), decreased activity of respiratory chain complexes, and altered mitochondrial dynamics, is observed in most liver diseases. Accumulating evidence has substantiated that the therapeutic potential of MSCs is mediated not only through their cell replacement and paracrine effects but also through their regulation of mitochondrial dysfunction in liver disease. Here, we comprehensively review the involvement of mitochondrial dysfunction in the development of liver disease and how MSCs can target mitochondrial dysfunction. We also discuss recent advances in a novel method that modifies MSCs to enhance their functions in liver disease. A full understanding of MSC restoration of mitochondrial function and the underlying mechanisms will provide innovative strategies for clinical applications. Video Abstract.

Expression changes of Tim-3 as one of supplementary indicators for monitoring prognosis of liver pathological changes in chronic HBV infection.

PURPOSE: This study was designed to analyze the liver tissue changes among the CHB patients who received treatment for at least 6 months and follow-up for at least 1 year, together with the correlation between the different disease condition and serum markers. METHODS: One-hundred and eighty-five CHB patients underwent antiviral therapy for at least 6 months were enrolled. In the 12-month follow-up, ultrasonography-guided biopsy was performed. The patients were grouped based on the serum markers and pathological changes in liver tissues. Then we determined the serum markers, virological tests and Tim-3 expression among these groups. RESULTS: Antiviral therapy significantly reduced liver inflammation indicators and serum Tim-3 level. However, the fibrosis process of liver tissue was not changed, and there are still disputes on the serum marker and hepatic lesion outcomes. Under normal liver function or negative hepatitis B e antigen (HBeAg) of CHB patients, there might be consensus between Tim-3 change and liver pathological outcome. According to the liver tissue inflammation and fibrosis conditions, Tim-3 was positively correlated with liver function indices. Besides, it was also related to fibrosis stage and inflammation grade. CONCLUSION: There were inconsistent changes between serum markers and liver tissue conditions after anti-viral therapy. Tim-3 expression was more suitable to indicate the changes of liver inflammatory and fibrosis response to some extent than ALT and AST. It may serve as a certain indicator to predict the CHB prognosis, which could be used as one of the monitoring indicators in liver pathological changes of chronic HBV infection, especially in monitoring liver tissue inflammation.

Neddylation inhibitor MLN4924 has anti-HBV activity via modulating the ERK-HNF1α-C/EBPα-HNF4α axis.

Hepatitis B virus (HBV) infection is a major public health problem. The high levels of HBV DNA and HBsAg are positively associated with the development of secondary liver diseases, including hepatocellular carcinoma (HCC). Current treatment with nucleos(t)ide analogues mainly reduces viral DNA, but has minimal, if any, inhibitory effect on the viral antigen. Although IFN reduces both HBV DNA and HBsAg, the serious associated side effects limit its use in clinic. Thus, there is an urgent demanding for novel anti-HBV therapy. In our study, viral parameters were determined in the supernatant of HepG2.2.15 cells, HBV-expressing Huh7 and HepG2 cells which transfected with HBV plasmids and in the serum of HBV mouse models with hydrodynamic injection of pAAV-HBV1.2 plasmid. RT-qPCR and Southern blot were performed to detect 35kb mRNA and cccDNA. RT-qPCR, Luciferase assay and Western blot were used to determine anti-HBV effects of MLN4924 and the underlying mechanisms. We found that treatment with MLN4924, the first-in-class neddylation inhibitor currently in several phase II clinical trials for anti-cancer application, effectively suppressed production of HBV DNA, HBsAg, 3.5kb HBV RNA as well as cccDNA. Mechanistically, MLN4924 blocks cullin neddylation and activates ERK to suppress the expression of several transcription factors required for HBV replication, including HNF1α, C/EBPα and HNF4α, leading to an effective blockage in the production of cccDNA and HBV antigen. Our study revealed that neddylation inhibitor MLN4924 has impressive anti-HBV activity by inhibiting HBV replication, thus providing sound rationale for future MLN4924 clinical trial as a novel anti-HBV therapy.

MiR-17 family-mediated regulation of Pknox1 influences hepatic steatosis and insulin signaling.

The aberrant expression of Pknox1 is associated with hepatic glucose and lipid dysmetabolism status of type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD). However, the underlying mechanism causing Pknox1 overexpression in this pathological status remains unclear. By using miRNA target prediction programs, we found that the 3'-UTR of the Pknox1 mRNA sequence contains highly conserved target sites of miR-17 family. In a rat model of streptozotocin and high-fat diet-induced T2DM and NAFLD complication, the increased hepatic expression of Pknox1 was consistent with decreased expressions of miR-17 family, especially miR-17 and miR-20a. Furthermore, an inverse correlation was observed between Pknox1 and miR-17 and miR-20a in free fatty acids-induced hepatocyte steatosis. Dual-luciferase reporter assay further showed that Pknox1 was a valid target gene of miR-17 family. The ectopic expression of miR-17 or miR-20a could markedly suppress Pknox1 expression in hepatocytes. MiR-17 or miR-20a overexpression also resulted in significantly enhanced insulin sensitivity and reduced hepatocyte steatosis in HepG2 and L02 cells, which were determined by altered phosphorylation on insulin receptor signaling pathway proteins and decreased intracellular triglyceride and lipid accumulation, respectively. These data implicate the upregulated hepatic expression of Pknox1 in T2DM complicated with NAFLD may be caused by the reduced expression of miR-17 family, indicating that developing miRNA-mediated regulation strategies on Pknox1 may provide new therapeutic options for metabolic disease.

Hepatic Macrophages are the Cell Source of Hepatic Procalcitonin in Acute Liver Failure.

BACKGROUND/AIMS: Serum procalcitonin (PCT) is elevated in acute liver failure (ALF), but the expression of PCT in the liver has not been elucidated. We aimed to clarify the regulation of hepatic PCT expression and the cell sources in ALF. METHODS: Human monocytic leukemia line U937 cells were treated with 12-O-tetradecanoylphorbol-l3-acetate (PMA) (100 ng/ mL) for 24 h to induce activated macrophages. In the presence of lipopolysaccharide (LPS, 1 µg/mL), activated macrophages and human hepatocyte line L02 cells were incubated with LPS or co-cultured for 0, 2, 6, and 24 h. In an in vivo experiment, male C57BL/6 mice were challenged with intraperitoneal LPS/D-galactosamine (LPS/D-GalN). Serum liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured using an automatic chemical analyzer. Inflammatory mediators were measured by real-time PCR and liver histology was examined by hematoxylin-eosin (HE) staining and immunohistochemistry (IHC). RESULTS: LPS induced the upregulation of PCT mRNA in U937-activated macrophages but not in L02 cells. When co-cultured with L02 cells, the expression of PCT mRNA of activated macrophages was upregulated compared to controls; however, the activated macrophages did not induce the expression of PCT mRNA in L02 cells in the presence of LPS. Moreover, serum liver enzymes (ALT, AST), inflammation, necrosis, and hepatic expression of PCT were significantly elevated in the LPS/D-GalN-challenged ALF mouse model. IHC revealed that PCT expression was co-localized with hepatic macrophages. CONCLUSIONS: Hepatic PCT expression is upregulated in ALF. Hepatic macrophages but not hepatocytes are the cell source of hepatic PCT expression.

Serum Procalcitonin Correlates with Renal Function in Hepatitis B Virus-Related Acute-on-Chronic Liver Failure.

BACKGROUND/AIMS: To investigate the relationship between elevated serum procalcitonin (PCT) and renal function in hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF). METHODS: HBV-ACLF patients (n = 201) presenting to the State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, from January 2013 to November 2016 were categorized into three groups according to serum PCT levels: (i) normal group (n = 74) had PCT of ≤ 0.5 ng/mL; (ii) elevated group (n = 85) had PCT in the range 0.5-1.0 ng/mL; and (iii) highly elevated group (n = 42) had PCT of > 1.0 ng/mL. Thirty-five cases received standard care after admission. Serum PCT levels and renal function were determined during a two-week follow-up. RESULTS: Significant increases in serum creatinine (Cr) were recorded in male and female patients in the elevated group and highly elevated group compared with the normal group (P < 0.05). In addition, serum Cr levels in male and female patients were significantly higher in the highly elevated group than in the elevated group (P < 0.05). The glomerular filtration rate (GFR) was significantly lower in the highly elevated group (P < 0.05) and this group had the highest risk of altered Cr (45.9% in males; 80% in females) and abnormal GFR (37.5%). Serum PCT levels correlated significantly with all renal function parameters including homocysteine (Hcy), GFR, Cr, blood urea nitrogen, uric acid, and cystatin C at baseline and during treatment. Univariate and multivariate analyses indicated that serum PCT was a strong predictor of renal dysfunction. CONCLUSION: Serum PCT is closely related to renal dysfunction in HBV-ACLF.

6-Methoxyethylamino-numonafide inhibits hepatocellular carcinoma xenograft growth as a single agent and in combination with sorafenib.

Hepatocellular carcinoma (HCC) is the third leading form of cancer worldwide, and its incidence is increasing rapidly in the United States, tripling over the past 3 decades. The current chemotherapeutic strategies against localized and metastatic HCC are ineffective. Here we report that 6-methoxyethylamino-numonafide (MEAN) is a potent growth inhibitor of murine xenografts of 2 human HCC cell lines. At the same dose and with the same treatment strategies, MEAN was more efficacious in inhibiting tumor growth in mice than sorafenib, the only approved drug for HCC. Treatment by MEAN at an effective dose for 6 wk was well tolerated by animals. Combined therapy using both sorafenib and MEAN enhanced tumor growth inhibition over monotherapy with either agent. Additional experiments revealed that MEAN inhibited tumor growth through mechanisms distinct from those of either its parent compound, amonafide, or sorafenib. MEAN suppressed C-MYC expression and increased expression of several tumor suppressor genes, including Src homology region 2 domain-containing phosphatase-1 (SHP-1) and TXNIP (thioredoxin-interacting protein). As an encouraging feature for envisioned clinical application, the IC50 of MEAN was not significantly changed in several drug-resistant cell lines with activated P-glycoprotein drug efflux pumps compared to drug-sensitive parent cells, demonstrating the ability of MEAN to be effective in cells resistant to existing chemotherapy regimens. MEAN is a promising candidate for clinical development as a single-agent therapy or in combination with sorafenib for the management of HCC.-Liu, Y., Lou, G., Norton, J. T., Wang, C., Kandela, I., Tang, S., Shank, N. I., Gupta, P., Huang, M., Avram, M. J., Green, R., Mazar, A., Appella, D., Chen, Z., Huang, S. 6-Methoxyethylamino-numonafide inhibits hepatocellular carcinoma xenograft growth as a single agent and in combination with sorafenib.

MiR-122 modification enhances the therapeutic efficacy of adipose tissue-derived mesenchymal stem cells against liver fibrosis.

Mesenchymal stem cell (MSC) transplantation alone may be insufficient for treatment of liver fibrosis because of complicated histopathological changes in the liver. Given that miR-122 plays an essential role in liver fibrosis by negatively regulating the proliferation and transactivation of hepatic stellate cells (HSCs), this study investigated whether miR-122 modification can improve the therapeutic efficacy of adipose tissue-derived MSCs in treating liver fibrosis. MiR-122-modified AMSCs (AMSC-122) were constructed through lentivirus-mediated transfer of pre-miR-122. MiR-122-modified AMSCs expressed high level of miR-122, while they retained their phenotype and differentiation potential as naïve AMSCs. AMSC-122 more effectively suppressed the proliferation of and collagen maturation in HSCs than scramble miRNA-modified AMSCs. In addition, AMSC-derived exosomes mediated the miR-122 communication between AMSCs and HSCs, further affecting the expression levels of miR-122 target genes, such as insulin-like growth factor receptor 1 (IGF1R), Cyclin G(1) (CCNG1) and prolyl-4-hydroxylase α1 (P4HA1), which are involved in proliferation of and collagen maturation in HSCs. Moreover, miR-122 modification enhanced the therapeutic efficacy of AMSCs in the treatment of carbon tetrachloride (CCl4 )-induced liver fibrosis by suppressing the activation of HSCs and alleviating collagen deposition. Results demonstrate that miR-122 modification improves the therapeutic efficacy of AMSCs through exosome-mediated miR-122 communication; thus, miR-122 modification is a new potential strategy for treatment of liver fibrosis.

Macrophage Inflammatory Protein-2 in High Mobility Group Box 1 Secretion of Macrophage Cells Exposed to Lipopolysaccharide.

BACKGROUND/AIMS: Macrophage inflammatory protein-2 (MIP-2), a type of leukocyte chemokine, is primarily produced by macrophages, and levels increase significantly in early inflammation. However, the precise biological functions and mechanisms of MIP-2 in the development of inflammation remain unclear. The purposes of the present study were to investigate the role of MIP-2 in inflammation induced by lipopolysaccharide (LPS) in vitro and to determine the possibility of blocking the high mobility group box 1 (HMGB1) signalling pathway via MIP-2 inhibition. METHODS: Macrophage cells (RAW264.7, U937 and THP-1 cells) were divided into control and treatments groups. Expression levels of interleukin-6 (IL-6), interleukin-1ß (IL-1ß), tumour necrosis factor-α (TNF-α), HMGB1, chemokine (C-C motif) ligand-2 (Ccl-2), Toll-like receptor-4 (TLR-4), inducible nitric oxide synthase (iNOS), phosphorylated MAPKs (p38, ERKs, JNKs), PI3K/Akts, JAKs/STAT3, IκB, and cytoplasmic and nuclear NF-κB p65 in RAW264.7 cells were detected by qRT-PCR, enzyme-linked immunosorbent assay (ELISA) or western blot assays. RESULTS: mip-2 siRNA and an anti-MIP-2 antibody significantly reduced the expression levels of Ccl-2, TLR-4, iNOS, IL-6, IL-1ß, HMGB1, and TNF-α in RAW264.7 cells exposed to LPS (P<0.01). Additionally, mRNA expression levels of HMGB1 and TLR-4 in cells treated with LPS+mip-2 siRNA were significantly lower than those in cells treated with LPS alone (P<0.01 or P<0.05). The MIP-2 antibody significantly suppressed activation of p38-MAPK, p-STAT3, and p-Akts and translocation of NF-κB p65 from the cytoplasm to the nucleus in RAW264.7 exposed to LPS (P<0.01 or P<0.05). CONCLUSION: mip-2 siRNA and the MIP-2 antibody can reduce the inflammatory effects induced by LPS in macrophage cells. The mechanisms may occur through down-regulation of p38-MAPK, STAT3 and Akts phosphorylation and translocation of NF-κB p65. MIP-2 plays an important role in inflammation induced by LPS.

MicroRNA-141 Targets Sirt1 and Inhibits Autophagy to Reduce HBV Replication.

BACKGROUND/AIMS: About 400 million individuals are chronically infected with hepatitis B virus, at high risk of developing liver cirrhosis and hepatocellular carcinoma. Recent studies have demonstrated an interaction between hepatitis B virus replication and autophagy activity of hepatocytes. In the present study, we aimed to investigate the role of miR-141 in regulating autophagy and hepatitis B virus replication. METHODS: The expression of HBV-DNA, miR-141 and Sirt1 mRNA was determined by quantitative real-time PCR analysis. The expression of HBsAg and HBeAg was determined by ELISA. Western blotting was performed to detect protein expression. The LC3 puncta was determined by immunofluorescence. To test whether miR-141 directly regulate the expression level of Sirt1 mRNA, dual-luciferase reporter gene assay was performed. RESULTS: In vitro studies showed that miR-141 mimic inhibited the autophagic response, hepatitis B virus and the expression of Sirt1 in hepatocytes. And transfection with miR-141 inhibitor enhanced autophagic response and Sirt1 expression. The autophagy induced by overexpression of Sirt1 was inhibited by miR-141 mimic. In addition, miR-141 mimic also decreased the expression of Sirt1 mRNA. Sirt1 was predicted as a potential miR-141 target by bioinformatic analysis of its 3'-UTR, and confirmed by luciferase reporter assays which analyzing the interaction of miR-141 with the wild- type or the mutated Sirt1 3'-UTR. CONCLUSION: We have therefore demonstrated a role of miR-141 in regulating autophagy-mediated hepatitis B virus inhibition by targeting Sirt1, and may provide potential targets for drug development.

The p53/miR-34a/SIRT1 Positive Feedback Loop in Quercetin-Induced Apoptosis.

BACKGROUND: The anti-tumor effects of quercetin have been reported, but the underlying molecular mechanisms remain to be elucidated. The aim of present study was to explore the role of miRNA in the anticancer effects of quercetin. METHODS: The differential miRNAs expression between the HepG2 and Huh7 cells treated by quercetin were detected by microarray. The xCELLigence, Flow cytometry, RT-PCR and Western blot were used to analyze the cell proliferation, cell apoptosis, cell cycle arrest, anti-tumor genes, and protein expression. RESULTS: miR-34a was up-regulated in HepG2 cells treated by quercetin exhibiting wild-type p53. When inhibiting the miR-34a, the sensitivity of the cells to quercetin decreased and the expression of the SIRT1 was up-regulated, but the acetylation of p53 and the expression of some genes related to p53 down-regulated. CONCLUSION: miR-34a plays an important role in the anti-tumor effects of querctin in HCC, miR-34a may be a tiemolecule between the p53 and SIRT1 and is composed of a p53/miR-34a/SIRT1 signal feedback loop, which could enhance apoptosis signal and significantly promote cell apoptosis.

Isoliquiritigenin Inhibits Interferon-γ-Inducible Genes Expression in Hepatocytes through Down-Regulating Activation of JAK1/STAT1, IRF3/MyD88, ERK/MAPK, JNK/MAPK and PI3K/Akt Signaling Pathways.

BACKGROUND & AIMS: The high expression levels of interferon-γ (IFN-γ)-inducible genes correlate positively with liver diseases. The present study aimed to explore the effect of isoliquiritigenin (ISL) on the expression of genes induced by IFN-γ in vitro, and to elucidate the underlying molecular mechanisms. METHODS: HepG2 and L02 cells were divided into control, ISL, IFN-γ, and IFN-γ plus ISL groups. The cytotoxicity of compounds to cells was evaluated by Cell Counting Kit 8 (CCK8) assay; the expression levels of chemokine (C-X-C motif) ligand 9 (CXCL9), CXCL10, CXCL11, and interleukin-6 (IL-6) in cells and supernatant were measured by quantitative real time polymerase chain reaction (qRT-PCR) and ELISA, respectively. Moreover, western blot was used to examine the phosphorylated levels of janus kinase (JAK)/signal transducer and activator of transcription 1 (STAT1), nuclear factor (NF)-κB, interferon regulatory factor 3 (IRF3)/myeloid differentiation factor 88 (MyD88), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K)/Protein Kinase B (Akt) in HepG2 and L02 cells exposed to ISL, IFN-γ and IFN-γ plus ISL. RESULTS: The results showed that IFN-γ treatment induced the expression of CXCL9, CXCL10, CXCL11, and IL-6 in HepG2 and LO2 cells, which could be significantly and dose-dependently inhibited by ISL treatment (P < 0.05 or P < 0.01), but the inhibitory effect of ISL on IL-6 expression was not so good as on CXCL9, CXCL10, and CXCL11 expression. Furthermore, ISL treatment dose-dependently inhibited the activation of JAK1/STAT1, IRF3/MyD88, extracellular signal-regulated kinase (ERK)/MAPK, c-Jun N-terminal kinase (JNK)/MAPK, and PI3K/Akt signaling pathways (P < 0.05), but had no effect on the activation of JAK2/STAT1, NF-κB and p38/MAPK signaling pathways. CONCLUSION: We demonstrate that ISL inhibits IFN-γ-induced inflammation in hepatocytes via influencing the activation of JAK1/STAT1, IRF3/MyD88, ERK/MAPK, JNK/MAPK, and PI3K/Akt signaling pathways.

Lipocalin 2 Upregulation Protects Hepatocytes from IL1-ß-Induced Stress.

BACKGROUND: Lipocalin 2 (LCN2), a protein primarily produced by hepatocytes, is highly upregulated under various conditions that induce cellular stress, such as intoxication, infection or inflammation. However, the precise biological functions and underlying mechanisms of LCN2 in hepatocytes remains unknown. METHODS: Hepatocyte stress was successfully induced by treating Huh7 cells with interleukin-1ß (IL-1ß). Interleukin-6 (IL-6), Tumor Necrosis Factor-α (TNF-α) and LCN2 levels were measured in IL-1ß treated Huh7 cells and supernatant. Additionally, microarray analysis was conducted to identify genes differentially expressed in LCN2-silenced and control Huh7 cells. RESULTS: TNF-α, IL-6 and LCN2 were significantly elevated in Huh7 cells after IL-1ß) treatment. In LCN2-silenced Huh7 cells, expression of IL-6 and TNF-α was significantly increased when compared with the expression levels of control Huh7 cells. Furthermore, differentially expressed genes were observed between the LCN2-silenced and control cells. Microarray analysis indicated that LCN2 acted by influencing genes involved in protein metabolism, stress response, cell cycle and proliferation. CONCLUSIONS: Our results suggest that LCN2 upregulation protects hepatocytes from IL-1ß-induced stress. Additionally, our microarray analysis of LCN2-silenced and control cells provides a better understanding of the mechanisms that may be influenced by LCN2 induction.

The sterile inflammation in the exacerbation of HBV-associated liver injury.

Exacerbation of hepatitis B virus-associated liver injury is characterized by abnormal immune response which not only mobilizes specific antiviral effects but also poses a potentially lethal nonspecific sterile inflammation to the host. How nonspecific sterile inflammation is triggered after the preexisting injury caused by specific immune injury remains elusive. In the setting of sterile inflammation, endogenous damage-associated molecular patterns are released by stressed and dying hepatocytes, which alarm the immune system through their potential pattern recognition receptors and related signaling pathways, orchestrate the influx of diverse cytokines, and ultimately amplify liver destruction. This review highlights current knowledge about the sterile hepatic inflammation in the exacerbation of chronic hepatitis B.