胆汁酸代謝に着目した脂肪性肝疾患の病態進行メカニズムの検討

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 國土 典宏, 東京大学准教授 牛久 哲男, 東京大学教授 鈴木 洋史, 東京大学准教授 池田 均, 東京大学准教授 山内 敏正University of Tokyo(東京大学

Nonstructural 5A Protein of Hepatitis C Virus Interferes with Toll-Like Receptor Signaling and Suppresses the Interferon Response in Mouse Liver.

The hepatitis C virus nonstructural protein NS5A is involved in resistance to the host immune response, as well as the viral lifecycle such as replication and maturation. Here, we established transgenic mice expressing NS5A protein in the liver and examined innate immune responses against lipopolysaccharide (LPS) in vivo. Intrahepatic gene expression levels of cytokines such as interleukin-6, tumor necrosis factor-α, and interferon-γ were significantly suppressed after LPS injection in the transgenic mouse liver. Induction of the C-C motif chemokine ligand 2, 4, and 5 was also suppressed. Phosphorylation of the signal transducer and activator of transcription 3, which is activated by cytokines, was also reduced, and expression levels of interferon-stimulated genes, 2'-5' oligoadenylate synthase, interferon-inducible double-stranded RNA-activated protein kinase, and myxovirus resistance 1 were similarly suppressed. Since LPS binds to toll-like receptor 4 and stimulates the downstream pathway leading to induction of these genes, we examined the extracellular signal-regulated kinase and IκB-α. The phosphorylation levels of these molecules were reduced in transgenic mouse liver, indicating that the pathway upstream of the molecules was disrupted by NS5A. Further analyses revealed that the interaction between interleukin-1 receptor-associated kinase-1 and tumor necrosis factor receptor associated factor-6 was dispersed in transgenic mice, suggesting that NS5A may interfere with this interaction via myeloid differentiation primary response gene 88, which was shown to interact with NS5A. Since the gut microbiota, a source of LPS, is known to be associated with pathological conditions in liver diseases, our results suggest the involvement of NS5A in the pathogenesis of HCV infected-liver via the suppression of innate immunity

Treatment and outcome of hepatorenal syndrome in Japan: a retrospective cohort study using a national inpatient database

Abstract Background Hepatorenal syndrome (HRS) is a life-threatening complication of end-stage liver disease. This study aimed to clarify the status of HRS in Japan by analyzing the Japanese Diagnosis Procedure Combination database. Methods Patients hospitalized for cirrhosis and HRS from July 2010 to March 2019 were sampled. They were divided into two groups according to their prognosis upon discharge: the transplant-free survival group and the death or liver transplantation group. The two groups’ baseline patient characteristics and treatments were compared. Results The mean age of the 1,412 participants was 67.3 years (standard deviation: 12.3 years), and 65.4% were male. The Child–Pugh grades was B and C in 18.8% and 81.2%, respectively. Hepatocellular carcinoma was present in 27.1% of the patients, and the proportion of spontaneous bacterial peritonitis was 2.3%. Albumin, noradrenaline, and dopamine were administered to 57.9%, 8.0%, and 14.9% of the patients, respectively; 7.0% of the patients underwent renal replacement therapy; and 5.0% were admitted to the intensive care unit. Intravenous antibiotics were administered to 30.8% of the patients. A total of 925 patients (65.5%) died or underwent liver transplantation. In addition to a higher proportion of patients with poor baseline liver function, the death or liver transplantation group included more males, patients with hepatocellular carcinoma, and those with spontaneous bacterial peritonitis. Conclusions HRS in Japan has a high mortality rate. Albumin was administered to over 50% of participants. Although noradrenaline is recommended in Japanese clinical guidelines, dopamine was more frequently used as a vasoconstrictor in clinical practice

Heterozygous knockout of Bile salt export pump ameliorates liver steatosis in mice fed a high-fat diet.

The incidence of nonalcoholic steatohepatitis (NASH) is increasing worldwide, including in Asian countries. We reported that the hepatic expression of bile salt export pump (BSEP) was downregulated in patients with NASH, suggesting that BSEP is involved in the pathogenesis of NASH. To identify the underlying mechanism, we analyzed Bsep heterozygous knock-out (Bsep+/- mice) and wild-type (WT) C57BL/6J mice fed a high-fat diet (HFD) (32.0% animal fat) or normal diet. We examined histological changes, levels of hepatic lipids and hepatic bile acids, and expression of genes related to bile acid and cholesterol metabolism. HFD-fed Bsep+/- mice exhibited milder hepatic steatosis and less weight gain, compared to HFD-fed WT mice. The concentrations of total bile acid, triglycerides, and cholesterols were reduced in the liver of HFD-fed Bsep+/- mice. Regarding hepatic bile acid metabolism, the expression levels of Farnesoid X receptor (Fxr) and Multidrug resistance-associated protein 2 were significantly upregulated in HFD-fed Bsep+/- mice, compared to HFD-fed WT mice. Furthermore, several alterations were observed in upstream cholesterol metabolism in the liver. The expression levels of bile acid metabolism-related genes were also altered in the intestine of HFD-fed Bsep+/- mice. In conclusion, HFD-fed Bsep+/- mice exhibited significant alterations of the expression levels of genes related to bile acid and lipid metabolism in both the liver and ileum, resulting in alleviated steatosis and less weight gain. These results suggest the importance of BSEP for maintenance of bile acid and cholesterol metabolism. Further investigations of the involvement of BSEP in the pathogenesis of NASH will provide greater insight and facilitate the development of novel therapeutic modalities

Using mHealth to Provide Mobile App Users With Visualization of Health Checkup Data and Educational Videos on Lifestyle-Related Diseases : Methodological Framework for Content Development

BACKGROUND: The number of people with lifestyle-related diseases continues to increase worldwide. Improving lifestyle behavior with health literacy may be the key to address lifestyle-related diseases. The delivery of educational videos using mobile health (mHealth) services can replace the conventional way of educating individuals, and visualization can replace the provision of health checkup data. OBJECTIVE: This paper aimed to describe the development of educational content for MIRAMED, a mobile app aimed at improving users' lifestyle behaviors and health literacy for lifestyle-related diseases. METHODS: All videos were based on a single unified framework to provide users with a consistent flow of information. The framework was later turned into a storyboard. The final video contents were created based on this storyboard and further discussions with leading experts and specialist physicians on effective communication with app users about lifestyle-related diseases. RESULTS: The app uses visualization of personal health checkup data and educational videos on lifestyle-related diseases based on the current health guidelines, scientific evidence, and expert opinions of leading specialist physicians in the respective fields. A total of 8 videos were created for specific lifestyle-related diseases affecting 8 organs: (1) brain-cerebrovascular disorder, (2) eyes-diabetic retinopathy, (3) lungs-chronic obstructive pulmonary disease, (4) heart-ischemic heart disease, (5) liver-fatty liver, (6) kidneys-chronic kidney disease (diabetic kidney disease), (7) blood vessels-peripheral arterial disease, and (8) nerves-diabetic neuropathy. CONCLUSIONS: Providing enhanced mHealth education using novel digital technologies to visualize conventional health checkup data and lifestyle-related diseases is an innovative strategy. Future studies to evaluate the efficacy of the developed content are planned

IGF-II Producing Hepatocellular Carcinoma Treated with Sorafenib: Metabolic Complications and a Foresight to Molecular Targeting Therapy to the IGF Signal

Hypoglycemia is a rare paraneoplastic manifestation of patients with neoplasms. Hypoglycemia can be induced by several causes, including an aberrant increase of hypoglycemic agents and adrenal insufficiency. Sorafenib is the first agent to demonstrate a survival benefit in the treatment of advanced hepatocellular carcinoma (HCC). This small molecule inhibits serine/threonine kinase RAF in tumor cells and tyrosine kinases VEGFR/PDGFR in tumor vasculature and decreases tumor growth and angiogenesis. In this paper, we report a case of HCC who was treated with sorafenib and showed severe hypoglycemia. This hypoglycemia might be induced by two causes, both adrenal insufficiency as an adverse effect of sorafenib and activation of the insulin-like growth factor (IGF) signal by excessive secretion of incompletely processed precursors of IGF-II. Although the IGF signal is suggested to be involved in aberrant growth of HCC in some cases, there is no other report showing the influence of sorafenib on HCC with active IGF signal. Unfortunately, the effect of sorafenib was limited in the present case. However, emerging drugs that directly inhibit the IGF signal can be expected to be highly effective in the treatment of HCC with hypoglycemia

Suppressed TLR signaling in the livers of LPS-injected NS5A-transgenic mice.

<p>(A) Phosphorylation levels of ERK, IκB-α, and IRF7 were determined by immunoblotting with phospho-specific antibodies in the livers of NS5A-transgenic (Tg) and non-transgenic (NT) mice injected with LPS. (B) Interaction between IRAK1 and TRAF6 was examined using an immunoprecipitation experiment. Liver tissue lysates of NS5A-transgenic (Tg) and non-transgenic (NT) mice were immunoprecipitated with anti-TRAF6 antibody and the immunoprecipitates were subjected to SDS-PAGE followed by immunoblotting with anti-IRAK1 and anti-TRAF6 antibodies. Whole cell lysates (WCL) were similarly subjected to immunoblotting with anti-IRAK1 and anti-vinculin antibodies.</p

Suppressed activation of STAT3 in NS5A-transgenic mice.

<p>(A) Phosphorylation levels of STAT3 were determined by immunoblotting with phospho-specific antibodies in the livers of NS5A-transgenic (Tg) and non-transgenic (NT) mice 6 h after injection with LPS or normal saline. (B) Liver tissue sections derived from LPS-injected transgenic (Tg) and nontransgenic (NT) mice were immunohistologically stained with an anti-phospho-STAT3 antibody. (C) DNA-binding activity of STAT3 was determined by EMSA. Shifted bands corresponding to DNA-bound STAT3 were shown (left panel). The specificity of the band was examined by adding 100-fold amount of non-labeled, identical (I) or mutated (M) oligonucleotides before the addition of labeled oligonucleotides (right panel).</p

Expression of NS5A in transgenic mice.

<p>(A) Expression levels of NS5A protein in liver tissues of NS5A-transgenic (Tg) and non-transgenic (NT) mice were determined by immunoblotting with mouse anti-NS5A antibody. As a positive control (PC), lysates of the HCV subgenomic replicon cells were used. The arrow represents the NS5A protein. The arrowhead indicates a nonspecific band observed only in mouse tissues. (B) mRNA expression levels of NS5A in the liver of transgenic mice and HCV-infected patients were determined using quantitative real-time PCR. The levels were standardized to the β-actin gene. The median value of human samples was defined as 1 in Y-axis. (C) Liver tissue sections of the 6-month-old NS5A-transgenic (Tg) and non-transgenic (NT) mice were histologically examined with H&E staining.</p