Association of Hepatobiliary Phase of Gadoxetic-Acid-Enhanced MRI Imaging with Immune Microenvironment and Response to Atezolizumab Plus Bevacizumab Treatment.

It has been reported that high intensity in the hepatobiliary (HB) phase of Gd-EOB-DTPA-enhanced MRI (EOB-MRI) is associated with an immune-cold microenvironment in HCC. The aim of this study is to reveal whether non-high-intensity HCCs are homogeneous with respect to the immune microenvironment and to investigate the predictive ability of EOB-MRI for the response to atezolizumab + bevacizumab therapy (Atezo/Bev). The association between differences in stepwise signal intensity of HB phase and molecular subtypes and somatic mutations associated with the immune microenvironment was investigated in 65 HCC patients (cohort 1). The association between EOB-MRI and the therapeutic effect of Atezo/Bev was evaluated in the Atezo/Bev cohort (60 patients in cohort 2). The proportion of HCCs having CTNNB1 mutations and classified as Chiang CTNNB1 and Hoshida S3 was high in the high-intensity HB-phase group. Infiltration of tumor-associated macrophages (TAM) and regulatory T-lymphocytes (Treg) was characteristic of the high-intensity and low-intensity groups, respectively. Although EOB-MRI could not predict the response to Atezo/Bev treatment, our results demonstrate that EOB-MRI could serve as a surrogate marker predicting the immune microenvironment. This suggests that Atezo/Bev treatment can be selected regardless of signal intensity in the EOB-MRI HB phase.

Participation of medical students in the medical team of sports events.

Including medical student volunteers in the medical team for the triathlon strengthens the medical team structure, and encourages medical students to involve in sports medicine. Family physicians who play a role in the medical team for sports events can adopt medical students as a member and can educate them.

The Analysis of Muscle Volume Measured by Bioelectrical Impedance in Patients with Hepatocellular Carcinoma Treated with First-Line Atezolizumab plus Bevacizumab Combination Therapy or First-Line Lenvatinib.

INTRODUCTION: Measurements of body composition, such as the skeletal muscle index (SMI), are useful for predicting prognosis in hepatocellular carcinoma (HCC). This study aimed to analyze the relationship between skeletal muscle changes during therapy with atezolizumab plus bevacizumab (Atezo + Beva) or lenvatinib (Len) and the association between SMI and prognosis. METHODS: Patients with advanced HCC and Child-Pugh A status received Atezo + Beva or Len as first-line systemic chemotherapy. We assessed prognosis and body composition obtained by bioelectrical impedance analysis. RESULTS: A total of 109 patients received treatment (Atezo + Beva, n = 47; Len, n = 62). During treatment, the arm SMI was reduced in the Len group and maintained in the Atezo + Beva group. The extracellular water to total body water ratio (ECW/TBW) increased significantly in both groups during treatment. In the Atezo + Beva group, no factor was associated with prognosis. Multivariate analysis showed that in the Len group, the arm SMI (hazard ratio [HR], 0.5; 95% CI: 0.26-0.89; p = 0.02), ECW/TBW (HR: 2.7; 95% CI: 1.21-6.01; p = 0.01), and Child-Pugh score (HR: 2.3; 95% CI: 1.31-6.13; p = 0.004) were associated with progression-free survival. CONCLUSION: Assessing body composition with BIA before Atezo + Beva and Len treatment may be useful.

Correlation between serum pro-inflammatory cytokine levels and the prognosis of the patients with acute liver failure.

BACKGROUND AND AIM: The prognosis of acute liver failure (ALF) remains poor, and liver transplantation is an alternative treatment option. Assessing the prognosis of ALF is important in determining treatment strategies. Here, we investigated clinical factors including serum pro-inflammatory cytokine levels that are associated with the prognosis of ALF. METHODS: Sixty-six patients who developed ALF were enrolled in this study. Serum concentrations of 12 pro-inflammatory cytokines were measured on admission. The prognosis and factors associated with survival and development of hepatic coma were analyzed. RESULTS: Of 66 patients, 4 patients underwent liver transplantation, and 49 patients were rescued without liver transplantation, while the remaining 13 patients died. Serum concentrations of interleukin (IL)-1ß, IL-4, IL-6, IL-8, IL-13, TNF, IFN -γ, IP-10, and G-CSF were significantly elevated in ALF patients. IL-4 and IL-8 levels were higher in patients who underwent liver transplantation or died than in rescued patients. Multivariable analysis identified age ≥ 55 years and IL-4 ≥ 1.2 pg/mL on admission as independent factors for mortality. Serum IL-8 levels were higher in patients with hepatic coma, and prothrombin-international normalized ratio ≥ 3.5 and IL-8 ≥ 77.2 pg/mL on admission were associated with development of hepatic coma after admission. CONCLUSION: Serum levels of several pro-inflammatory cytokines were elevated in ALF patients. IL-4 and IL-8 were correlated with survival and development of hepatic coma after admission, respectively. Measurement of serum pro-inflammatory cytokines seems to be useful for the management of ALF.

Serum interleukin-6 level predicts the prognosis for patients with alcohol-related acute-on-chronic liver failure.

AIM: Heavy alcohol consumption is the most common etiology of acute-on-chronic liver failure (ACLF) in Japan. In some patients, ACLF is associated with a fatal outcome in less than 6 months. We evaluated the prognosis of patients with alcohol-related ACLF in our cohort and explored the prognostic factors. METHODS: Forty-six patients with alcoholic liver cirrhosis who fulfilled the Japanese diagnostic criteria for ACLF, including those classified as extended and/or probable, were enrolled in this study. Serum concentrations of inflammatory cytokines (interleukin [IL]-1ß, IL-6, IL-8, IL-10, IL-12p70 and TNFα) were measured. We assessed prognosis and identified factors associated with survival. RESULTS: During the median 33-day observation period, 19 patients died, and 3 patients underwent living donor liver transplantation. Cumulative survival rates of patients treated without liver transplantation were 69, 48, 41, and 36% at 1, 3, 6, and 12 months, respectively. Eighteen of the 19 deceased patients died within 6 months after ACLF diagnosis. Serum concentrations of inflammatory cytokines were significantly elevated, and patients who underwent liver transplantation or who died within 6 months after admission had significantly higher serum IL-6 levels than the survival group. Multivariate analysis identified IL-6 > 23.3 pg/mL at admission and model for end-stage liver disease (MELD) score ≥ 25 on day 4 of admission as significant independent factors for mortality within 6 months. CONCLUSION: Serum IL-6 level and Day-4 MELD were prognostic factors for alcohol-related ACLF. Early liver transplantation is a potential treatment option for patients whose prognosis is expected to be poor.

HBV with precore and basal core promoter mutations exhibits a high replication phenotype and causes ER stress-mediated cell death in humanized liver chimeric mice.

BACKGROUND AND AIMS: Mutations within the precore (PC) and basal core promoter (BCP) regions of the HBV genome are associated with fulminant hepatitis and HBV reactivation. These mutations may enhance viral replication, but little is known about whether they directly induce damage to the liver. We investigated mechanisms of direct cytopathic effects induced by the infection with PC/BCP mutants in the absence of immune response in vitro and in vivo . APPROACH AND RESULTS: Mice with humanized livers and hepatocytes derived from humanized mice were infected with either wild-type or mutant-type PC/BCP HBV, and the HBV replication and human hepatocyte damage were evaluated. HBV proliferated vigorously in mice with PC/BCP-mutant infection, and the severe loss of human hepatocytes with a slight human ALT elevation subsequently occurred only in PC/BCP mutant mice. In PC/BCP mutant infection, the accumulation of HBsAg in humanized livers colocalized with the endoplasmic reticulum, leading to apoptosis through unfolded protein response in HBV-infected hepatocytes. RNA-sequencing revealed the molecular characteristics of the phenotype of PC/BCP mutant infection in a humanized mouse model. Reduced ALT elevation and higher HBV DNA levels in this model are consistent with characteristics of HBV reactivation, indicating that the hepatocyte damage in this model might mimic HBV reactivation followed by hepatocyte damage under immunosuppressive conditions. CONCLUSION: PC and BCP mutations were associated with enhanced viral replication and cell death induced by ER stress using HBV infection models. These mutations might be associated with liver damage in patients with fulminant hepatitis or HBV reactivation.

Acute liver injury in a non-alcoholic fatty liver disease patient with chloroform exposure: a case report.

We report a rare case of acute liver injury by daily exposure to small amounts of chloroform in non-alcoholic fatty liver disease (NAFLD) patient. The patient had been followed up in our hospital every 3 months. Although his alanine aminotransferase (ALT) levels were steady around 30 ~ 60 U/L until August 2014, ALT level was spontaneously increased to more than 1,000 U/L at the follow-up point in late August 2014. As he was diagnosed as acute liver injury by chloroform exposure, we withdrew him from the exposure of chloroform and treated him with 600 mg/day of ursodeoxycholic acid. Afterwards, his ALT level rapidly improved and normalized within 1 month. To verify the influences of chloroform exposure, we measured plasma chloroform levels by gas chromatography. Although plasma chloroform concentration was 7.1 ng/ml (normal range: < 0.2 ng/ml) at the time of liver injury, the concentration had decreased to 0.7 ng/ml by 1 month later. Despite the fact that he had put on a face mask to protect from aspiration of chloroform, liver injury still occurred in the present case. Chloroform has a high solubility for lipids and accumulation of lipids in the liver might become a risk factor for liver injury by chloroform.

A novel cDNA-uPA/SCID/Rag2-/- /Jak3-/- mouse model for hepatitis virus infection and reconstruction of human immune system.

Although human hepatocyte-transplanted immunodeficient mice support infection with hepatitis viruses, these mice fail to develop viral hepatitis due to the lack of an adaptive immune system. In this study, we generated new immunodeficiency cDNA-urokinase-type plasminogen activator (uPA)/SCID/Rag2-/- /Jak3-/- mice and established a mouse model with both a humanized liver and immune system. Transplantation of human hepatocytes with human leukocyte antigen (HLA)-A24 resulted in establishment of a highly replaced liver in cDNA-uPA/SCID/Rag2-/- /Jak3-/- mice. These mice were successfully infected with hepatitis B virus (HBV) and hepatitis C virus (HCV) for a prolonged period and facilitate analysis of the effect of anti-HCV drugs. Administration of peripheral blood mononuclear cells (PBMCs) obtained from an HLA-A24 donor resulted in establishment of 22.6%-81.3% human CD45-positive mononuclear cell chimerism in liver-infiltrating cells without causing graft-versus-host disease in cDNA-uPA/SCID/Rag2-/- /Jak3-/- mice without human hepatocyte transplantation. When mice were transplanted with human hepatocytes and then administered HLA-A24-positive human PBMCs, an alloimmune response between transplanted human hepatocytes and PBMCs occurred, with production of transplanted hepatocyte-specific anti-HLA antibody. In conclusion, we succeeded in establishing a humanized liver/immune system characterized by an allo-reaction between transplanted human immune cells and human liver using a novel cDNA-uPA/SCID/Rag2-/- /Jak3-/- mouse. This mouse model can be used to generate a chronic hepatitis mouse model with a human immune system with application not only to hepatitis virus virology but also to investigation of the pathology of post-transplantation liver rejection.

Hepatitis B Virus (HBV) Upregulates TRAIL-R3 Expression in Hepatocytes Resulting in Escape From Both Cell Apoptosis and Suppression of HBV Replication by TRAIL.

BACKGROUND: Hepatitis B virus (HBV) evades host immunity by regulating intracellular signals. To clarify this immune tolerance mechanism, we performed gene expression analysis using HBV-infected humanized mouse livers. METHODS: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 3 (TRAIL-R3) was significantly upregulated in livers of HBV-infected human hepatocyte transplanted mice by cDNA microarray and next-generation sequencing. We analyzed the significance of TRAIL-R3 upregulation in HBV infection using human hepatocyte transplanted mice and HepG2 cell lines. RESULTS: TRAIL-R3 induction by HBV infection was verified by in vitro and in vivo HBV replication models, and induction was inhibited by antiviral nucleot(s)ide analogue treatment. TRAIL-R3 transcription was regulated by the TRAIL-R3 promoter at -969 to -479 nucleotides upstream from the transcription start site, and by hepatitis B x (HBx) via activation of nuclear factor-κB (NF-κB) signal. TRAIL not only induced cell apoptosis but also inhibited HBV replication. TRAIL-R3 upregulation could inhibit both TRAIL-dependent apoptosis in HBV-infected hepatocytes and TRAIL-mediated suppression of HBV replication. CONCLUSIONS: These results suggest a mechanism by which HBV persists by escaping host immunity through upregulation of TRAIL-R3. Development of novel drugs to inhibit this escape system might lead to complete HBV elimination from human hepatocytes.

Hepatic venous pressure gradient after balloon-occluded retrograde transvenous obliteration and liver stiffness measurement predict the prognosis of patients with gastric varices.

BACKGROUND: Balloon-occluded retrograde transvenous obliteration (BRTO) is a treatment option for patients with gastric varices (GVs). This study aimed to clarify the clinical significance of portal hypertension estimated by the hepatic venous pressure gradient (HVPG), subsequent exacerbation of esophageal varices (EVs), and prognosis of patients who underwent BRTO for GVs. METHODS: Thirty-six patients with GVs treated with BRTO were enrolled in this study, and their HVPG was measured before (pre-HVPG) and on the day after BRTO (post-HVPG). After BRTO, patients were followed-up for a median interval of 24.5 (3-140) months. Clinical factors related to EVs exacerbation and prognosis after BRTO were retrospectively analyzed. RESULTS: Post-HVPG increased compared to pre-HVPG in 21 out of 36 patients (58%), and post-HVPG was overall significantly higher compared to pre-HVPG (P = 0.009). During the observation period, 19 patients (53%) developed EVs exacerbation, and the cumulative EVs exacerbation rates at 1, 3 and 5 years after BRTO were 27%, 67%, and 73%, respectively. Pre-HVPG was not related to EVs exacerbation, although elevation of post-HVPG to ≥ 13 mmHg (P < 0.01) and high level of serum aspartate aminotransferase (P < 0.05) were significant independent risk factors for EVs exacerbation after BRTO. Fourteen patients (38.9%) died during the observation period. An elevated value of liver stiffness measurement (LSM) of ≥ 21 kPa was a significant independent risk factor for poor prognosis after BRTO (P < 0.05). CONCLUSIONS: HVPG increases after BRTO. HVPG after BRTO has greater predictive ability for subsequent EVs exacerbation than HVPG before BRTO. LSM is a potential prognostic parameter in patients who undergo BRTO.

The presence of vessels encapsulating tumor clusters is associated with an immunosuppressive tumor microenvironment in hepatocellular carcinoma.

Recently, a distinct vascular pattern in hepatocellular carcinoma (HCC) called vessels encapsulating tumor-forming clusters (VETC) has received attention because of its association with poor prognosis. However, little is known about the mechanism by which VETC promotes an aggressive phenotype at the molecular level. In our study, the association between differences in stepwise signal intensity in the HB phase and molecular subtypes and somatic mutations associated with the immune microenvironment were investigated using the International Cancer Genome Consortium (ICGC) cohort (66 patients). To our knowledge, this is the first study to analyze the molecular patterns of VETC using RNA-Seq data. The VETC+ HCC group showed significantly lower overall survival and higher cumulative incidence of extrahepatic metastasis after curative hepatic resection than the VETC- HCC group. The VETC+ group exhibited molecular features indicative of lower immune activation than the VETC- group, suggesting that tumor cells in the VETC+ group were more likely to escape from the immune response, which could lead to the shorter OS (Overall survival) and higher risk of metastasis. On the other hand, gene expression levels of fibroblast growth factor receptors were upregulated in VETC+ HCC, suggesting that VETC+ HCC might benefit from lenvatinib treatment. Our results demonstrate that VETC+ HCC was associated with the suppression of tumor immune responses at the molecular level.

Efficacy and safety of chemoradiation therapy using one-shot cisplatin via hepatic arterial infusion for advanced hepatocellular carcinoma with major macrovascular invasion: a single-arm retrospective cohort study.

BACKGROUND: Patients with hepatocellular carcinoma (HCC) and macrovascular invasion (MVI) who receive systemic chemotherapy have a poor prognosis. This study aimed to determine if one-shot cisplatin (CDDP) chemotherapy via hepatic arterial infusion (HAI) combined with radiation therapy (RT) prior to systemic chemotherapy could improve the outcomes of these patients. METHODS: This study consisted of 32 HCC patients with the following eligibility criteria: (i) portal vein invasion 3/4 and/or hepatic vein invasion 2/3; (ii) received one-shot CDDP via HAI; (iii) received RT for MVI, (iv) a Child-Pugh score ≤ 7; and (v) an Eastern Clinical Oncology Group Performance Status score of 0 or 1. To determine the therapeutic effect, we collected information on patient characteristics and took contrast-enhanced computed tomography at the start of the therapy and every 2 to 4 months after the start of therapy. We evaluated the overall response of the tumor and tumor thrombosis according to modified Response Evaluation Criteria in Solid Tumors. We assessed patient data using the Mann-Whitney U and Fisher exact tests and evaluated overall survival and progression-free survival using the log-rank test. RESULTS: The overall response rate at the first evaluation performed a median of 1.4 weeks after HAI was 16% for the main intrahepatic tumor and 59% for the MVI. The best responses were the same as those of the first-time responses. The duration of median survival was 8.6 months, and progression-free survival of the main intrahepatic tumor was 3.2 months. Predictive factors for overall survival were the relative tumor volume in the liver and the first therapeutic response of MVI. There were no severe adverse events or radiation-induced hepatic complications. CONCLUSIONS: One-shot CDDP via HAI and RT were well tolerated and showed immediate and favorable control of MVI. Thus, this combination shows potential as a bridging therapy to systemic chemotherapy.

A dual conditional CRISPR-Cas9 system to activate gene editing and reduce off-target effects in human stem cells.

The CRISPR-Cas9 system has emerged as a powerful and efficient tool for genome editing. An important drawback of the CRISPR-Cas9 system is the constitutive endonuclease activity when Cas9 endonuclease and its sgRNA are co-expressed. This constitutive activity results in undesirable off-target effects that hinder studies using the system, such as probing gene functions or its therapeutic use in humans. Here, we describe a convenient method that allows temporal and tight control of CRISPR-Cas9 activity by combining transcriptional regulation of Cas9 expression and protein stability control of Cas9 in human stem cells. To achieve this dual control, we combined the doxycycline-inducible system for transcriptional regulation and FKBP12-derived destabilizing domain fused to Cas9 for protein stability regulation. We showed that approximately 5%-10% of Cas9 expression was observed when only one of the two controls was applied. By combining two systems, we markedly lowered the baseline Cas9 expression and limited the exposure time of Cas9 endonuclease in the cell, resulting in little or no undesirable on- or off-target effects. We anticipate that this dual conditional CRISPR-Cas9 system can serve as a valuable tool for systematic characterization and identification of genes for various pathological processes.

Promoting mechanism of serum amyloid a family expression in mouse intestinal epithelial cells.

Serum amyloid A (SAA) is an acute phase inflammatory protein that we previously described as a robust biomarker of colorectal inflammation in patients with ulcerative colitis (UC) in clinical remission. However, what induces SAA expression in UC remains unclear. This study demonstrates that SAA is significantly expressed in the intestinal tract of UC mouse models when compared with C-reactive protein, another inflammatory biomarker. Moreover, interleukin-6 and tumor necrosis factor-α were found to promote SAA1 expression, as were Toll-like receptor ligands flagellin and lipopolysaccharide. Furthermore, results suggested that the nuclear factor-kappa B (NF-κB) pathway may be involved in the promotion of SAA1 expression by flagellin, which was inhibited by treatment with 5-aminosalicylic acid (5-ASA). Therefore, the flagellin/NF-κB/SAA1 axis may represent one of the mechanisms by which 5-ASA suppresses intestinal inflammation.

Gemella haemolysans as an emerging pathogen for bacteremia among the elderly.

We report a patient of an 82-year-old woman with occult Gemella haemolysans bacteremia without a clear entry site. Gemella haemolysans is part of the normal human flora but can cause severe systemic infections such as infective endocarditis on rare occasions. In this patient, physical examination showed no localized symptoms, and a transthoracic echocardiogram showed no vegetation on the heart valves. The entry site for this pathogen was unclear. As the number of the elderly with asymptomatic infections has been increasing, clinicians should be aware of that this microorganism can cause occult bacteremia and infective endocarditis.

The importance of body composition assessment for patients with advanced hepatocellular carcinoma by bioelectrical impedance analysis in lenvatinib treatment.

BACKGROUND AND AIMS: The aim of this study was to investigate the relationship between body composition before lenvatinib treatment and prognosis in patients with hepatocellular carcinoma (HCC). We also assessed the relationship between the rate of change in body composition after lenvatinib treatment and prognosis. METHODS: Eighty-one patients with advanced HCC who were treated with lenvatinib were enrolled. We assessed prognosis, various clinical data, body composition parameters obtained by bioelectrical impedance analysis (BIA), and handgrip strength. RESULTS: Multivariate analysis showed that an extracellular water to total body water ratio (ECW/TBW) ≤ 0.400 at treatment initiation was associated with longer overall survival (OS), progression-free survival (PFS), and post-progression survival (PPS) (OS: hazard ratio [H0R], 4.72; 95% CI, 12.03-11.00; P < 0.001; PFS: HR, 2.66; 95% CI, 1.33-5.34; P = 0.0057; PPS: HR, 3.08; 95% CI, 1.32-7.18; P = 0.0093). Multivariate analysis also showed that the skeletal muscle mass index (SMI) of the arm at treatment initiation was associated with a longer PFS (HR, 2.12; 95% CI, 1.23-3.64; P = 0.0069). In the group with an ECW/TBW ≤ 0.400 before lenvatinib treatment, univariate analysis showed that the rate of change in only the arm SMI was associated with a longer OS and PFS. CONCLUSION: Body composition assessment by BIA before and after lenvatinib treatment is useful in predicting prognosis in lenvatinib-treated patients with HCC.

Genetically edited hepatic cells expressing the NTCP-S267F variant are resistant to hepatitis B virus infection.

The sodium-dependent taurocholate co-transporting polypeptide (NTCP)-S267F variant is known to be associated with a reduced risk of hepatitis B virus (HBV) infection and disease progression. The NTCP-S267F variant displays diminished function in mediating HBV entry, but its function in HBV infection has not been fully established in more biologically relevant models. We introduced the NTCP-S267F variant and tested infectivity by HBV in genetically edited hepatic cells. HepG2-NTCP clones with both homozygous and heterozygous variants were identified after CRISPR base editing. NTCP-S267F homozygous clones did not support HBV infection. The heterozygote clones behaved similarly to wild-type clones. We generated genetically edited human stem cells with the NTCP-S267F variant, which differentiated equally well as wild-type into hepatocyte-like cells (HLCs) expressing high levels of hepatocyte differentiation markers. We confirmed that HLCs with homozygous variant did not support HBV infection, and heterozygous variant clones were infected with HBV equally as well as the wild-type cells. In conclusion, we successfully introduced the S267F variant by CRISPR base editing into the NTCP/SLC10A gene of hepatocytes, and showed that the variant is a loss-of-function mutation. This technology of studying genetic variants and their pathogenesis in a natural context is potentially valuable for therapeutic intervention against HBV.

Novel drug resistance-associated substitutions against pibrentasvir emerged in genotype 1b hepatitis C virus-infected human hepatocyte transplanted mice.

Combination therapy with glecaprevir and pibrentasvir (PIB) has high efficacy for patients with hepatitis C virus (HCV) infection except among those who experienced NS5A-P32 deletion (del) mutation during prior DAA treatment failure. However, some patients fail to achieve SVR through combination treatment even in the absence of NS5A-P32del. We analyzed emergence of NS5A resistance-associated substitutions (RASs) against PIB using HCV-infected mice. Male human hepatocyte transplanted mice were infected with genotype 1b wild-type HCV. Mice were treated with PIB, resulting in a transient decrease in serum HCV RNA levels but followed by relapse during the treatment. Direct sequence analysis showed emergences of various mutations in the NS5A region, including L31V/P32del, L31F/P32del/Y93H, NS5A-P29del/Y85C, and NS5A-F37Y. PIB was less effective in mice with NS5A-F37Y mutations compared to mice with wild-type HCV. NS5A-F37Y showed 5.4-fold resistance to PIB relative to wild-type based on analysis using HCV subgenomic replicon systems. The present in vivo and in vitro studies identified NS5A-F37Y as a novel RAS against PIB and showed the possibility of emergence of various NS5A RASs including P29del, P32del and F37Y following PIB treatment. These mutations might emerge and lead to failure to respond to DAA therapies including PIB-based regimens in chronic hepatitis C patients.

In vitro analysis of hepatic stellate cell activation influenced by transmembrane 6 superfamily 2 polymorphism.

Non­alcoholic steatohepatitis (NASH) may progress via liver fibrosis along with hepatic stellate cell (HSC) activation. A single nucleotide polymorphism (SNP; rs58542926) located in transmembrane 6 superfamily 2 (TM6SF2) has been reported to be significantly associated with fibrosis in patients with NASH, but the precise mechanism is still unknown. The present study aimed to explore the role of TM6SF2 in HSC activation in vitro. Plasmids producing TM6SF2 wild-type (WT) and mutant type (MT) containing E167K amino acid substitution were constructed, and the activation of LX­2 cells was analyzed by overexpressing or knocking down TM6SF2 under transforming growth factor ß1 (TGFß) treatment. Intracellular α­smooth muscle actin (αSMA) expression in LX­2 cells was significantly repressed by TM6SF2­WT overexpression and increased by TM6SF2 knockdown. Following treatment with TGFß, αSMA expression was restored in TM6SF2­WT overexpressed LX­2 cells and was enhanced in TM6SF2 knocked­down LX­2 cells. Comparing αSMA expression under TM6SF2­WT or ­MT overexpression, expression of αSMA in TM6SF2­MT overexpressed cells was higher than that in TM6SF2­WT cells and was further enhanced by TGFß treatment. The present study demonstrated that intracellular αSMA expression in HCS was negatively regulated by TM6SF2 while the E167K substitution released this negative regulation and led to enhanced HSC activation by TGFß. These results suggest that the SNP in TM6SF2 may relate to sensitivity of HSC activation.