Published papers

Background: Pathological angiogenesis is involved in the development of hepatocellular carcinoma. In patients with chronic hepatitis C (CHC), the level of angiogenic factor angiopoietin (ANGP)-2 is reported to be increased in the blood, correlating with fibrosis. In this study, we aimed to clarify whether blood ANGP-2 is useful as a biomarker for liver angiogenesis and fibrosis in CHC patients and to further reveal the relationship between such pathology in a carbon tetrachloride (CCl4)-treated liver fibrosis mouse model. Methods: Plasma levels of ANGP-2, expression of a liver sinusoidal endothelial cell (LSEC) marker (CD31), collagen deposition (Sirius Red staining) in the liver, clinical fibrosis markers (Mac-2 binding protein glycosylation isomer, virtual touch quantification, and liver stiffness measurement), and liver function (albumin bilirubin score) were examined in CHC patients. To determine the effects of an anti-angiogenic agent on liver fibrosis in vivo, sorafenib was administered to the CCl4-treated mice (BALB/c male). Results: The plasma levels of ANGP-2 were increased in CHC patients compared to healthy volunteers and decreased by the eradication of hepatitis C with direct-acting antivirals. In addition, plasma ANGP-2 levels were correlated with CD31 expression, collagen deposition, clinical fibrosis markers, and liver function. Sorafenib inhibited liver angiogenesis and fibrosis in the CCl4-treated mice and was accompanied by decreased ANGP-2 expression in LSECs. Conclusions: ANGP-2 may serve as a useful biomarker for liver angiogenesis and fibrosis in CHC patients. In addition, angiogenesis and fibrosis may be closely related.

Congestive hepatopathy (CH) with chronic passive congestion is characterized by the progression of liver fibrosis without prominent inflammation and hepatocellular damage. Currently, the lack of reliable biomarkers for liver fibrosis in CH often precludes the clinical management of patients with CH. To explore fibrosis biomarkers, we performed proteome analysis on serum exosomes isolated from patients with CH after the Fontan procedure. Exosomal cluster of differentiation (CD)44 levels were increased in patients with CH compared to healthy volunteers and was accompanied by increases in serum levels of soluble CD44 and CD44 expression in the liver. To address the roles of CD44 in CH, we established a mouse model of chronic liver congestion by partial inferior vena cava ligation (pIVCL) that mimics CH by fibrosis progression with less inflammation and cellular damage. In the pIVCL mice, enhanced CD44 expression in hepatic stellate cells (HSCs) and deposition of its ligand hyaluronan were observed in the liver. Blood levels of soluble CD44 were correlated with liver fibrosis. The blockade of CD44 with specific antibody inhibited liver fibrosis in pIVCL mice and was accompanied by a reduction in S100 calcium-binding protein A4 expression following activation of HSCs. Conclusion: Chronic liver congestion promotes fibrosis through CD44. This identifies CD44 as a novel biomarker and therapeutic target of liver fibrosis in patients with CH.

Background: NASH is an increasingly common cause of chronic liver disease and can progress to cirrhosis and HCC. Although exercise suppresses inflammation during acute hepatitis, its impact on the progression of chronic liver disease remains unclear. Here, we investigated the effects of exercise on disease progression and intrahepatic immune cell composition in a mouse model of NASH. Method: Mice were assigned to 4 groups: 2 control groups (normal diet) and 2 NASH groups (western diet and low-dose carbon tetrachloride injection). One of each group remained sedentary and one was exercised on a treadmill for 12 weeks (60 min/d, 5 times/wk). All mice were then analyzed for liver histomorphology, steatosis, inflammation, and fibrosis; liver, adipose tissue, and skeletal muscle expression of genes related to metabolism and inflammation; and intrahepatic immune cell composition. Result: Compared with the normal diet mice, NASH mice exhibited enhanced liver steatosis, inflammation, and fibrosis; upregulated expression of liver lipogenesis-related and inflammation-related genes; and increased frequencies of intrahepatic F4/80int CD11bhi bone marrow-derived macrophages and programmed death receptor-1 (PD-1)+ CD8+ T cells. Expression of inflammatory cytokines and the frequencies of bone marrow-derived macrophages and PD-1+ CD8+ T cells correlated positively with liver steatosis, inflammation, and fibrosis. Exercise was shown to reduce NASH-induced hepatic steatosis, liver inflammation, and fibrosis; induce alterations in metabolism-related genes and inflammatory cytokines in the liver; and suppress accumulation of liver bone marrow-derived macrophages and PD-1+ CD8+ T cells. In addition, we showed that exercise induced increased expression of IL-15 in muscle and its deficiency exacerbated the pathology of NASH. Conclusions: Exercise alters the intrahepatic immune cell profile and protects against disease progression in a mouse model of NASH.

Vaccine immunogenicity is influenced by the vaccinee's genetic background. Here, we perform a genome-wide association study of vaccine-induced SARS-CoV-2-specific immunoglobulin G (IgG) antibody titers and T cell immune responses in 1,559 mRNA-1273 and 537 BNT162b2 vaccinees of Japanese ancestry. SARS-CoV-2-specific antibody titers are associated with the immunoglobulin heavy chain (IGH) and major histocompatibility complex (MHC) locus, and T cell responses are associated with MHC. The lead variants at IGH contain a population-specific missense variant (rs1043109-C; p.Leu192Val) in the immunoglobulin heavy constant gamma 1 gene (IGHG1), with a strong decreasing effect (β = −0.54). Antibody-titer-associated variants modulate circulating immune regulatory proteins (e.g., LILRB4 and FCRL6). Age-related hematopoietic expanded mosaic chromosomal alterations (mCAs) affecting MHC and IGH also impair antibody production. MHC-/IGH-affecting mCAs confer infectious and immune disease risk, including sepsis and Graves’ disease. Impacts of expanded mosaic loss of chromosomes X/Y on these phenotypes were examined. Altogether, both germline and somatic mutations contribute to adaptive immunity functions.

Background: Hepatitis B surface antigen (HBsAg) loss is an ideal goal for chronic hepatitis B patients. Antiretroviral therapy (ART) in hepatitis B virus/human immunodeficiency virus-1 (HBV/HIV-1)-coinfected patients can lead to hepatic flare (HF) caused by immune reconstitution-induced inflammatory syndrome (IRIS). Here, we investigated the impact of IRIS-HF on HBsAg loss. Methods: This was a retrospective study of 58 HBV/HIV-1-coinfected subjects HBsAg-positive for ≥6 months before ART initiation and followed for ≥1 year (median 9.9 years) after ART initiation. We examined humoral factors in sera from healthy volunteers, HIV-monoinfected patients, and HBV/HIV-1-coinfected patients with IRIS-HF or acute hepatitis B infection. Results: During ART, HBsAg loss was observed in 20 of 58 HBV/HIV-1-coinfected patients (34.5%). Of the 58 patients, 15 (25.9%) developed IRIS-HF within 12 months of ART initiation. HBsAg loss was more frequent among patients who developed IRIS-HF (11/15, 73.3%) than those who did not (9/43, 20.9%). Multivariate analysis showed IRIS-HF was an independent predictor of subsequent HBsAg loss. Younger age and higher baseline HBV DNA titer were associated with IRIS-HF. Elevation of sCD163, not CXCL9, CXC10, CXCXL11, or CXCL13, was observed at IRIS-HF. Conclusions: IRIS-HF was associated with HBsAg loss in HBV/HIV-1-coinfected patients.

Non-alcoholic fatty liver disease (NAFLD) is a progressive disorder that can develop into liver fibrosis and hepatocellular carcinoma. Natural killer (NK) cells have been shown to protect against liver fibrosis and tumorigenesis, suggesting that they may also play a role in the pathogenesis of NAFLD. Sialic acid-binding immunoglobulin-like lectins (Siglecs) are a family of inhibitory and activating receptors expressed by many cell types, including NK cells. Here, we investigated the phenotypic profiles of peripheral blood and intrahepatic NK cells, including expression of Siglecs and immune checkpoint molecules, and their association with NK cell function in patients with NAFLD. Immune cells in the peripheral blood of 42 patients with biopsy-proven NAFLD and 13 healthy volunteers (HVs) were identified by mass cytometry. The function of various NK cell subpopulations was assessed by flow cytometric detection of intracellular IFN-γ and CD107a/LAMP-1, a degranulation marker, after in vitro stimulation. We found that peripheral blood from NAFLD patients, regardless of fibrosis stage, contained significantly fewer total CD56+ NK cell and CD56dim NK cell populations compared with HVs, and the CD56dim cells from NAFLD patients were functionally impaired. Among the Siglecs examined, NK cells predominantly expressed Siglec-7 and Siglec-9, and both the expression levels of Siglec-7 and Siglec-9 on NK cells and the frequencies of Siglec-7+CD56dim NK cells were reduced in NAFLD patients. Notably, Siglec-7 levels on CD56dim NK cells were inversely correlated with PD-1, CD57, and ILT2 levels and positively correlated with NKp30 and NKp46 levels. Further subtyping of NK cells identified a highly dysfunctional Siglec-7−CD57+PD-1+CD56dim NK cell subset that was increased in patients with NAFLD, even those with mild liver fibrosis. Intrahepatic NK cells from NAFLD patients expressed elevated levels of NKG2D and CD69, suggesting a more activated phenotype than normal liver NK cells. These data identify a close association between NK cell function and expression of Siglec-7, CD57, and PD-1 that could potentially be therapeutically targeted in NAFLD.

Aim: In patients with liver cirrhosis, high levels of serum myostatin are associated with poor prognosis. We aimed to clarify the influence of myostatin on the prognosis of patients with non-alcoholic fatty liver disease–hepatocellular carcinoma (NAFLD-HCC) without cirrhosis and on the progression of liver fibrosis. Methods: Serum myostatin levels were evaluated in 234 patients who underwent primary surgical resection for single HCC. To clarify the impact of myostatin on liver fibrosis, we established human primary liver fibroblasts from resected livers, and cultured them in the presence of myostatin. Results: The median age was 67.4 years, the median L3 skeletal muscle mass index was 44.4 cm2/m2, and the median body mass index was 23.4 kg/m2. Eighty-two (35.0%) patients had sarcopenia (L3 skeletal muscle mass index: men <42, women <38 cm2/m2). The etiologies of liver disease were hepatitis B virus (n = 61), hepatitis C virus (n = 86), and non-B non-C hepatitis (n = 87) including NAFLD (n = 74). High preoperative serum myostatin and vascular invasion were independent predictors of poor overall survival (OS). High serum myostatin was associated with poor OS in patients with no sarcopenia (n = 152). In patients without advanced liver fibrosis (Fibrosis stage, 0–2; n = 58), high levels of serum myostatin were also associated with poor OS, regardless of sarcopenia. Serum myostatin levels were increased with the progression of liver fibrosis. Liver fibroblasts were activated and produced collagen following stimulation with myostatin. Conclusions: In patients with NAFLD-HCC without advanced liver fibrosis, high levels of serum myostatin were associated with poor OS. Myostatin activated primary fibroblasts and stimulated collagen production.

Aim: Congestive hepatopathy often leads to liver fibrosis and hepatocellular carcinoma. Imaging modalities provided clinical evidence that elevation of liver stiffness and tumor occurrence are mainly induced in the periphery of the liver in patients with congestive hepatopathy. However, clinical relevance of liver stiffness and liver fibrosis is unclear because liver congestion itself increases liver stiffness in congestive hepatopathy. It also unclear which factors configure such regional disparity of tumor development in patients with congestive hepatopathy. To answer these questions, we evaluated the macroscopic spatial distribution of liver fibrosis and tumors in the murine model of congestive hepatopathy. Methods: Chronic liver congestion was induced by partial ligation of the suprahepatic inferior vena cava. Distribution of liver congestion, fibrosis, and tumors in partial ligation of the suprahepatic inferior vena cava mice were assessed by histological findings, laser microdissection (LMD)-based qPCR and enhanced computed tomography. LMD-based RNA-sequencing was performed to identify causal factors that promote tumor development in congestive hepatopathy. Results: Liver fibrosis was mainly induced in the periphery of the liver and co-localized with distribution of liver congestion. Liver tumors were also induced in the periphery of the liver where liver congestion and fibrosis occurred. LMD-based RNA-sequencing revealed the upregulation of extracellular matrix/collagen fibril-, wound healing-, angiogenesis-, morphogenesis-, and cell motility-related signaling pathways in periphery of liver compared with liver center. Conclusions: Our findings showed the experimental relevance of liver congestion, fibrosis, and tumor development in congestive hepatopathy, and may provide important locational information. Macroscopic regional disparity observed in this murine model should be considered to manage patients with congestive hepatopathy.

Overall response rates of systemic therapies against advanced hepatocellular carcinoma (HCC) remain unsatisfactory. Thus, searching for new immunotherapy targets is indispensable. NK cells are crucial effectors and regulators in the tumor microenvironment and a determinant of responsiveness to checkpoint inhibitors. We revealed the landscape of NK cell phenotypes in HCC patients to find potential immunotherapy targets. Using single cell mass cytometry, we analyzed 32 surface markers on CD56dim and CD56bright NK cells, which included Sialic acid-binding immunoglobulin-type lectins (Siglecs). We compared peripheral NK cells between HCC patients and healthy volunteers. We also compared NK cells, in terms of their localizations, on an individual patient bases between peripheral and intrahepatic NK cells from cancerous and noncancerous liver tissues. In the HCC patient periphery, CD160+CD56dim NK cells that expressed Siglec-7, NKp46, and NKp30 were reduced, while CD49a+CD56dim NK cells that expressed Siglec-10 were increased. CD160 and CD49a on CD56dim NK cells were significantly correlated to other NK-related markers in HCC patients, which suggested that CD160 and CD49a were signature molecules. CD49a+ CX3CR1+ Siglec-10+ NK cells had accumulated in HCC tissues. Considering further functional analyses, CD160, CD49a, CX3CR1, and Siglec-10 on CD56dim NK cells may be targets for immunotherapies of HCC patients.

Aim: Although the survival rate after living-donor liver transplantation (LDLT) is improving, sepsis still limits the prognosis. Immune dysfunction and sarcopenia are often observed in LDLT patients, and increase susceptibility to infection. Brain-derived neurotrophic factor (BDNF) is a myokine produced by immune cells and skeletal muscle. We aimed to determine whether serum BDNF could be a feasible biomarker for sepsis of LDLT patients. Methods: We measured serum samples from 124 patients who underwent LDLT and 9 healthy volunteers for BDNF. We examined its correlation with incidence rate of sepsis. To clarify the source of BDNF, we examined its expression in lymphocytes, skeletal muscle cells, and hepatocytes. Results: Patients who experienced sepsis showed worse short-term survival. Preoperative serum BDNF was lower in LDLT patients compared with healthy volunteers, and was also lower in Child–Pugh C compared with Child–Pugh A or B. Serum BDNF was inversely correlated with Model for End-Stage Liver Disease and controlling nutritional status (CONUT) scores, but had a weak positive correlation with skeletal muscle mass index (SMI). Multivariate analysis revealed that serum BDNF was independently associated with sepsis. Preoperative serum BDNF was a better predictor of sepsis in LDLT patients than CONUT score or SMI. Serum BDNF was positively correlated with lymphocyte counts, especially T cells. In vitro, T cells and skeletal muscle cells produced BDNF. Conclusions: Preoperative serum BDNF could be a predictive biomarker for sepsis after LDLT, by reflecting the systemic condition including hepatic function, nutritional status, and immune status.

Background and Aims: Chronic liver congestion reflecting right-sided heart failure (RHF), Budd-Chiari syndrome, or Fontan-associated liver disease (FALD) is involved in liver fibrosis and HCC. However, molecular mechanisms of fibrosis and HCC in chronic liver congestion remain poorly understood. Approach and Results: Here, we first demonstrated that chronic liver congestion promoted HCC and metastatic liver tumor growth using murine model of chronic liver congestion by partial inferior vena cava ligation (pIVCL). As the initial step triggering HCC promotion and fibrosis, gut-derived lipopolysaccharide (LPS) appeared to induce LSECs capillarization in mice and in vitro. LSEC capillarization was also confirmed in patients with FALD. Mitogenic factor, sphingosine-1-phosphate (S1P), was increased in congestive liver and expression of sphingosine kinase 1, a major synthetase of S1P, was increased in capillarized LSECs after pIVCL. Inhibition of S1P receptor (S1PR) 1 (Ex26) and S1PR2 (JTE013) mitigated HCC development and liver fibrosis, respectively. Antimicrobial treatment lowered portal blood LPS concentration, LSEC capillarization, and liver S1P concentration accompanied by reduction of HCC development and fibrosis in the congestive liver. Conclusions: In conclusion, chronic liver congestion promotes HCC development and liver fibrosis by S1P production from LPS-induced capillarized LSECs. Careful treatment of both RHF and liver cancer might be necessary for patients with RHF with primary or metastatic liver cancer.

Backgrounds and Aims: Toll-like receptor (TLR) agonists have been developed as adjuvants to efficiently induce antiviral immune responses. Specificity and potency of these compounds are essential requirements for clinical trial applications. In patients with hepatitis B virus (HBV) infections, sustained loss of hepatitis B surface antigen (HBsAg) is a therapeutic goal, which may be achievable by the sequential activation of follicular helper T cells (Tfh) and antibody-secreting B cells. We aimed to elucidate whether novel TLR7 agonist, GS-986, could activate immune responses involved in HBV elimination. Methods: To clarify the impact of GS-986 on pDCs, we quantified the expression levels of surface markers and evaluated for Tfh induction in a culture model consisting of human pDCs with allogeneic naïve CD4+ T cells. In addition, we examined whether GS-986 could enhance HBs antibody production capacity using PBMC from CHB patients. Results: pDCs from CHB patients had lower OX40L expression and as well as impaired capacity for Tfh induction compared with those from healthy donors. However, GS-986–stimulated pDCs from CHB patients expressed OX40L and produced IL-6 and IL-12, resulting in the induction of IL-21–producing Tfh cells (CXCR5+PD-1+CD4+) from naïve CD4+ T cells. The Tfh-inducing capacity of GS-986 was reduced in the presence of an anti-OX40L blocking antibody. Furthermore, GS-986 promoted HBsAg-specific antibody production in PBMCs from CHB patients. Conclusions: GS-986 is an adjuvant that stimulates pDCs to induce Tfh differentiation and antigen-specific B-cell production. This immune profile may be beneficial for therapeutic application as an immune modulator in CHB patients.