Satoshi Yamagiwa

Sustained response to interferon‐α plus ribavirin therapy for chronic hepatitis C is closely associated with increased dynamism of intrahepatic natural killer and natural killer T cells

Aim:  Previous studies have revealed that functional impairment of innate immune cells, including natural killer (NK) and natural killer T (NKT) cells, might be associated with the persistence of hepatitis C virus (HCV) infection. However, the involvement of innate immune cells, which predominate in the liver, in therapeutic HCV clearance is still unclear.

Blockade of interferon-γ-inducible protein-10 attenuates chronic experimental colitis by blocking cellular trafficking and protecting intestinal epithelial cells

The role of chemokines, especially CXCL10/interferon‐γ‐inducible protein 10 kDa (IP‐10), a chemokine to attract CXCR3+ T‐helper 1‐type CD4+ T cells, is largely unknown in the pathophysiology of inflammatory bowel disease; ulcerative colitis and Crohns disease. The authors have earlier shown that IP‐10 neutralization protected mice from acute colitis by protecting crypt epithelial cells of the colon. To investigate the therapeutic effect of neutralization of IP‐10 on chronic colitis, an anti‐IP‐10 antibody was injected into mice with newly established murine AIDS (MAIDS) colitis. Anti‐IP‐10 antibody treatment reduced the number of colon infiltrating cells when compared to those mice given a control antibody. The treatment made the length of the crypt of the colon greater than control antibody. The number of Ki67+ proliferating epithelial cells was increased by the anti‐IP‐10 antibody treatment. Terminal deoxynucleotidyl transferase‐mediated dUTP nick‐end labeling (TUNEL)+ apoptotic cells were observed in the epithelial cells of the luminal tops of crypts in control MAIDS colitis, whereas TUNEL+ apoptotic epithelial cells were rarely observed with anti‐IP‐10 antibody treatment. In conclusion, blockade of IP‐10 attenuated MAIDS colitis through blocking cellular trafficking and protecting intestinal epithelial cells, suggesting that IP‐10 plays a key role in the development of inflammatory bowel disease as well as in chronic experimental colitis.

MEK/ERK signaling is a critical mediator for integrin-induced cell scattering in highly metastatic hepatocellular carcinoma cells.

The human hepatocellular carcinoma (HCC)-derived cell line KYN-2 is thought to provide a good model for studying the molecular basis of invasion and metastasis of human HCC, because it often shows cell scattering in vitro and intrahepatic metastasis in vivo. We previously found that integrin-mediated extracellular signals inactivated E-cadherin in KYN-2, and caused loss of cell–cell contact with gain of cell motility, which is considered to be a critical step in the process of cancer cell invasion and metastasis. To further understand molecular mechanisms involved in biological aggressiveness of HCC, we investigated intracellular signaling involved in integrin-mediated scattering of KYN-2 cells. Cultured KYN-2 cells formed trabecular aggregates in suspension, but when adhering to integrin-stimulating substrata, they scattered according to phosphorylation of extracellular signal-regulated kinase (ERK). Upon treatment with ERK kinase (MEK) inhibitor PD98059, adhered KYN-2 cell scattering was inhibited, tight cell-to-cell contact was recovered, and both E-cadherin and actin filaments accumulated in the area of intercellular contact zone. In contrast, constitutively active MEK1-transfected KYN-2 cells showed reduced E-cadherin and actin filaments in the intercellular contact zone, showing a flattened phenotype with broad lamellipodia. Enforced signaling of MEK-ERK pathway in KYN-2 cells suppressed cadherin-mediated homotypic adhesion and increased the potential of cell motility. An antibody-based protein microarray analysis revealed that the cytoplasmic protein c-Cbl was significantly downregulated in MEK1-transfected KYN-2 cells, suggesting that c-Cbl might be a candidate downstream mediator of integrin/MEK/ERK-mediated cell scattering. In conclusion, cell scattering of the highly metastatic cell line KYN-2 is regulated through the integrin-MEK-ERK signaling cascade, suggesting that this molecular pathway may be critical in intrahepatic metastasis of human HCC.

High viral loads, serum alanine aminotransferase and gender are predictive factors for the development of hepatocellular carcinoma from viral compensated liver cirrhosis

The aims of the present study were to determine the occurrence rate of hepatocellular carcinoma (HCC) and to assess the risk factors for the development of HCC in compensated viral liver cirrhosis.

Natural killer cell receptors and their ligands in liver diseases

The liver is a distinctive immune organ with predominant innate immunity, being rich in innate immune cells such as natural killer (NK) cells. In humans, NK cells comprise about 30%–50% of intrahepatic lymphocytes, whereas peripheral blood lymphocytes contain about 5%–20% NK cells. Accumulating evidence suggests that NK cells play an important role not only in host defense against invading microorganisms and tumor transformation in the liver but also in liver injury and repair. In recent years, significant progress has been made in terms of understanding how NK cells recognize their target cells and carry out their effector functions. It is now clear that NK cells are strictly regulated by numerous activating and inhibitory NK cell receptors that recognize various classes of cell surface ligands, some of which are expressed by normal healthy cells. Therefore, to further elucidate the involvement of NK cells in the pathogenesis of liver diseases, an understanding of recent advances in NK cell biology is crucial. This review provides an overview of recent advances in our knowledge of human NK cell receptors and their ligands in the context of liver diseases.

Kinetic analysis of the development of pancreatic lesions in mice infected with a murine retrovirus

Sjögrens syndrome (SjS)-like sialoadenitis and exocrine pancreatitis were induced in mice infected with LP-BM5 murine leukemia virus, which induces a severe immunodeficiency termed murine AIDS (MAIDS). All mice with MAIDS showed advancing cellular infiltration around the pancreatic ducts as well as systemic exocrinopathy. The primary target tissue of the pancreas was acinar cells, and the pancreatic islets were well preserved until a late phase of the disease. Immunofluorescence and flow cytometry demonstrated that CD4(+) T cells, Mac-1(+) cells, and B220(+) cells were major inflammatory components, and IFN-gamma and IL-10 were mainly detected on CD4(+) T and Mac-1(+) cells in the pancreas. Both Th1 and Th2 cells were found. TUNEL(+) apoptotic cells were mostly detected among pancreas-infiltrating cells. Fas ligand and TNF-alpha were also detected among pancreas-infiltrating cells, whereas Fas was rarely expressed in the pancreatic acinar cells. Thus, MAIDS mice could be valuable for analyzing the pathogenesis of autoimmune-related pancreatitis associated with SjS.

Mechanisms Involved in Enteropathy Induced by Administration of Nonsteroidal Antiinflammatory Drugs (NSAIDS)

Mice received oral indomethacin (1 mg/mouse) daily for five days. It was found that severe gastroenteropathy (ie, paralytic stomach and necrotic intestine) was induced on the sixth day. Ulcer formation was also seen at many sites in the digestive tract, especially in the colon. In parallel with the increase in the number of leukocytes in the digestive tract, the proportion of granulocytes increased at various sites, for example, in the intraepithelium and lamina propria of the colon and the lamina propria of the appendix. The number of extrathymic T cells at these sites in the digestive tract, especially γδ T cells in the colon, increased. A functional assay revealed that granulocytes isolated from mice injected with indomethacin were activated in terms of their superoxide production upon stimulation. In conjunction with the data on the simultaneous activation of granulocytes in the liver and blood, the present results suggest that nonsteroidal antiinflammatory drugs (NSAIDs) have the potential to induce severe granulocytosis in specific sites of the body, possibly via their stimulatory effect on the sympathetic nervous system (ie, granulocytes bear adrenergic receptors on their surface).

Autoantibodies in primary biliary cirrhosis: recent progress in research on the pathogenetic and clinical significance.

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic liver disease characterized by immune-mediated destruction of the small- and medium-sized intrahepatic bile ducts and the presence of antimitochondrial antibodies (AMA) in the serum. AMA are detected in over 90% of patients with PBC, whereas their prevalence in the general population is extremely low, varying from 0.16% to 1%. Previous studies have shown that the unique characteristics of biliary epithelial cells undergoing apoptosis may result in a highly direct and very specific immune response to mitochondrial autoantigens. Moreover, recent studies have demonstrated that serum from AMA-positive PBC patients is reactive with a number of xenobiotic modified E2 subunits of the pyruvate dehydrogenase complex, which is not observed in the serum of normal individuals. These findings indicate that chemicals originating from the environment may be associated with a breakdown in the tolerance to mitochondrial autoantigens. While it is currently generally accepted that AMA are the most specific serological markers of PBC, more than 60 autoantibodies have been investigated in patients with PBC, and some have previously been considered specific to other autoimmune diseases. This review covers the recent progress in research on the pathogenetic and clinical significance of important autoantibodies in PBC. Determining the pathogenic role of those autoantibodies in PBC remains a priority of basic and clinical research.

Recurrence of primary biliary cirrhosis and primary sclerosing cholangitis after liver transplantation in Japan.

Although there was some initial controversy, there is now a consensus that primary biliary cirrhosis (PBC) does indeed recur in both cadaveric and living donated allografts. Recurrence rate after deceased donor liver transplantation (LT) was reported to be 10.9–23% at 5 years. In the present study, we reviewed 221 PBC patients who underwent living‐donor liver transplantation (LDLT) in Japan. The 5‐year overall survival rate was 79%, and the rate of recurrence based on histological findings was 10% (7/70) after a median time of 36 months. Primary immunosuppression, withdrawal of corticosteroids and human leukocyte antigen matches were not associated with the recurrence. Recurrent PBC appears to have little impact on graft function and survival, but this may become a greater problem with longer follow up.

DNA Damage Sensor γ-H2AX Is Increased in Preneoplastic Lesions of Hepatocellular Carcinoma

Background. Phosphorylated histone H2AX (γ-H2AX) is a potential regulator of DNA repair and is a useful tool for detecting DNA damage. To evaluate the clinical usefulness of γ-H2AX in hepatocellular carcinoma (HCC), we measured the level of γ-H2AX in HCC, dysplastic nodule, and nontumorous liver diseases. Methods. The level of γ-H2AX was measured by immunohistochemistry in fifty-eight HCC, 18 chronic hepatitis, 22 liver cirrhosis, and 19 dysplastic nodules. Appropriate cases were also examined by fluorescence analysis and western blotting. Results. All cases with chronic liver disease showed increased levels of γ-H2AX expression. In 40 (69.9%) of 58 cases with HCC, the labeling index (LI) of γ-H2AX was above 50% and was inversely correlated with the histological grade. Mean γ-H2AX LI was the highest in dysplastic nodule (74.1 ± 22.1%), which was significantly higher than HCC (P < 0.005). Moreover, γ-H2AX was significantly increased in nontumorous tissues of HCC as compared with liver cirrhosis without HCC (62.5 ± 24.7%, from 5.1 to 96.0%, P < 0.005). Conclusions. γ-H2AX was increased in the preneoplastic lesions of HCC and might be a useful biomarker for predicting the risk of HCC.