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BACKGROUND: The impact of extended steroid administration on patients with autoimmune pancreatitis after a 3-year maintenance period remains poorly understood. This study analyzed the advantage and disadvantage of continuing steroid therapy beyond 3 years. METHODS: In this retrospective multicenter study across 17 institutions, patients who successfully completed 3 years of maintenance therapy without experiencing relapse were categorized into two groups: the maintenance therapy discontinuation group, who discontinued steroid therapy after the initial 3-year period, and maintenance therapy continuation group, who continued steroid therapy beyond 3 years. The cumulative relapse rate after 3 years of maintenance therapy was the primary outcome. Relapse predictors were compared using the Gray test for cumulative relapse incidence by specific factor. RESULTS: Of 211 patients, 105 experienced no relapse during the 3-year maintenance therapy and were divided into two groups: 69 in the maintenance therapy discontinuation group and 36 in the maintenance therapy continuation group. The relapse rate was lower in the maintenance therapy continuation group than in the maintenance therapy discontinuation group (P = 0.035). Predictors of relapse after 3 years included cessation of maintenance therapy (hazard ratio [HR] = 3.76; 95 % confidence interval [CI] = 1.07-13.3, P = 0.040) and renal involvement (HR = 2.88; 95 % CI = 1.04-7.99, P = 0.042). The maintenance therapy continuation group showed a significantly higher prevalence of macrovascular complications, compared with the maintenance therapy discontinuation group (P = 0.005). CONCLUSIONS: Cessation of steroid maintenance therapy and renal involvement were predictors of relapse after 3 years of maintenance therapy. However, the long-term use of steroids may increase the risk of macrovascular complications.
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Enfermedades Autoinmunes , Pancreatitis Autoinmune , Humanos , Pancreatitis Autoinmune/complicaciones , Estudios Retrospectivos , Enfermedades Autoinmunes/tratamiento farmacológico , Enfermedades Autoinmunes/complicaciones , Esteroides/efectos adversos , Enfermedad Crónica , RecurrenciaRESUMEN
A 34-year-old female patient with epigastric pain was admitted to our hospital. She reported an underlying condition of Rendu-Osler-Weber disease and a history of coil embolization for pulmonary arteriovenous fistula. A blood test revealed high hepatobiliary enzyme levels. An abdominal contrast-enhanced computed tomography revealed numerous arterioportal and arteriovenous shunts in the liver and a high-density area in the bile duct, which was diagnosed as biliary bleeding. She underwent transpapillary biliary drainage by endoscopic retrograde cholangiopancreatography, but recurrent biliary bleeding caused cholangitis, which was complicated by multiple liver abscesses. She was awaiting her turn for liver transplantation from brain-dead donors, but the liver abscesses were difficult to improve. Further, liver failure, septic pulmonary embolism, and disseminated intravascular coagulation were complicated. Thus, recurrent further biliary bleeding resulted in hemorrhagic shock, which required frequent blood transfusions. Furthermore, the continuous abscess to the intrahepatic bile duct in the anterior superior segment penetrated her diaphragm, causing hemothorax and eventually, death. Establishing progressive treatment, including liver transplantation, is considered necessary for this intractable disease.
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Fístula Arteriovenosa , Absceso Hepático , Fallo Hepático , Telangiectasia Hemorrágica Hereditaria , Humanos , Femenino , Adulto , Telangiectasia Hemorrágica Hereditaria/complicaciones , Fístula Arteriovenosa/complicaciones , Fallo Hepático/complicaciones , Colangiopancreatografia Retrógrada Endoscópica , HemorragiaRESUMEN
Various extrinsic signals tightly control hematopoietic stem cell quiescence. Our recent study showed that hematopoietic stem cells are regulated by a special FoxP3+ regulatory T-cell population with high expression of a hematopoietic stem cell marker, CD150. Extracellular adenosine generated via a cell-surface ectoenzyme CD39 on CD150high regulatory T cells maintained hematopoietic stem cell quiescence. It remains unclear how conventional T cells and the other cell-surface ectoenzyme, CD73, contribute to regulation of hematopoietic stem cells. This work shows that CD150high regulatory T cells as well as unique CD150high CD4+ conventional T cells regulate hematopoietic stem cells via CD73. Global CD73 deletion increased the numbers of hematopoietic stem cells, cycling stem cell frequencies, and levels of reactive oxygen species in hematopoietic stem cells. In vivo antioxidant treatment inhibited the increase of hematopoietic stem cells in CD73 knockout mice, suggesting that CD73 maintains stem cell quiescence by preventing oxidative stress. High levels of CD73 expression were frequently found on CD150high regulatory T cells and CD150high FoxP3-CD4+ T cells within the bone marrow. Transfer of these CD150high regulatory T cells and CD150high CD4+ conventional T cells abolished the increase of hematopoietic stem cells in CD73 knockout mice. In addition, the increase of stem cells in CD73 knockout mice was also inhibited by pharmacological activation of adenosine receptor 2A which is highly expressed by hematopoietic stem cells. Taken together, these results suggest that CD73 of CD150high regulatory T cells and CD150high CD4+ conventional T cells protects hematopoietic stem cells from oxidative stress, maintaining stem cell quiescence via adenosine receptor 2A.
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5'-Nucleotidasa/metabolismo , Linfocitos T CD4-Positivos/metabolismo , Células Madre Hematopoyéticas/citología , Células Madre Hematopoyéticas/metabolismo , Miembro 1 de la Familia de Moléculas Señalizadoras de la Activación Linfocitaria/metabolismo , Linfocitos T Reguladores/metabolismo , Animales , Biomarcadores , Linfocitos T CD4-Positivos/efectos de los fármacos , Linfocitos T CD4-Positivos/inmunología , Proteínas Ligadas a GPI/metabolismo , Células Madre Hematopoyéticas/efectos de los fármacos , Inmunofenotipificación , Activación de Linfocitos , Ratones , Ratones Noqueados , Estrés Oxidativo , Agonistas del Receptor Purinérgico P1/farmacología , Linfocitos T Reguladores/efectos de los fármacos , Linfocitos T Reguladores/inmunologíaAsunto(s)
Colestasis , Obstrucción Duodenal , Atresia Intestinal , Humanos , Stents/efectos adversos , Endoscopios , Drenaje , Colestasis/etiología , Colestasis/cirugíaRESUMEN
Discovery of a high-risk group for pancreatic cancer is important for prevention of pancreatic cancer. The present study was conducted as a nested case-control study including 170 pancreatic cancer cases and 340 matched controls of our population-based cohort study involving 30 239 subjects who answered a baseline questionnaire and supplied blood samples. Twelve targeted metabolites were quantitatively analyzed by gas chromatography/tandem mass spectrometry. Odds ratios (OR) and their corresponding 95% confidence intervals (CI) were calculated using conditional logistic regression models. Statistically significant P-value was defined as P < .05. Increasing 1,5-anhydro-d-glucitol (1,5-AG) levels were associated with a decreasing trend in pancreatic cancer risk (OR of quartile 4 [Q4], 0.50; 95% CI, 0.27-0.93; P = .02). Increasing methionine levels were also associated with an increasing trend of pancreatic cancer risk (OR of Q4, 1.79; 95% CI, 0.94-3.40: P = .03). Additional adjustment for potential confounders attenuated the observed associations of 1,5-AG and methionine (P for trend = .06 and .07, respectively). Comparing subjects diagnosed in the first 0-6 years, higher levels of 1,5-AG, asparagine, tyrosine and uric acid showed a decreasing trend for pancreatic cancer risk (P for trend = .04, .04, .04 and .02, respectively), even after adjustment for potential confounders. We found that the 12 target metabolites were not associated with pancreatic cancer risk. However, metabolic changes in the subjects diagnosed in the first 0-6 years showed a similar tendency to our previous reports. These results might suggest that these metabolites are useful for early detection but not for prediction of pancreatic cancer.
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Metaboloma , Neoplasias Pancreáticas/metabolismo , Adulto , Anciano , Asparagina/análisis , Estudios de Casos y Controles , Desoxiglucosa/análisis , Femenino , Humanos , Modelos Logísticos , Masculino , Metionina/análisis , Persona de Mediana Edad , Neoplasias Pancreáticas/etiología , Estudios Prospectivos , RiesgoAsunto(s)
Várices Esofágicas y Gástricas , Hemostasis Endoscópica , Humanos , Hemorragia Gastrointestinal/etiología , Hemorragia Gastrointestinal/terapia , Cianoacrilatos/uso terapéutico , Várices Esofágicas y Gástricas/complicaciones , Várices Esofágicas y Gástricas/terapia , Campos Visuales , Inmersión , Resultado del Tratamiento , RecurrenciaRESUMEN
BACKGROUND & AIMS: Antiviral agents including entecavir (ETV) suppress the replication of the hepatitis B virus (HBV) genome in human hepatocytes, but they do not reduce the abundance of viral proteins. The present study focused on effectively reducing viral protein levels. METHODS: We designed siRNAs (HBV-siRNA) that target consensus sequences in HBV genomes. To prevent the emergence of escaped mutant virus, we mixed three HBV-siRNAs (HBV-siRNAmix); the mixture was encapsulated in a novel pH-sensitive multifunctional envelope-type nanodevice (MEND), a hepatocyte-specific drug delivery system. Coagulation factor 7 siRNA was used to assess delivery and knockdown efficiencies of MEND/siRNA treatments in mice. The potency of MEND/HBV-siRNAmix was evaluated in primary human hepatocytes and in chimeric mice with humanized liver persistently infected with HBV. RESULTS: Effective knockdown of targets, efficient delivery of siRNA, and liver-specific delivery were each observed with MEND. MEND/HBV-siRNA caused efficient reduction of HBsAg and HBeAg in vitro and in vivo. However, ETV treatment did not efficiently reduce HBsAg or HBeAg when compared with a single MEND/HBV-siRNAmix treatment. Furthermore, the suppressive effects of a single dose of MEND/HBV-siRNAmix persisted for 14days in vitro and in vivo. CONCLUSION: We demonstrated that MEND/HBV-siRNA controlled HBV more efficiently than did ETV. Furthermore, the effect of a single dose of MEND/HBV-siRNA persisted for a long time. These results indicated that MEND/HBV-siRNA may be a promising novel HBV treatment that is more effective than reverse transcriptase inhibitors.
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Técnicas de Transferencia de Gen , Hepatitis B Crónica/terapia , ARN Interferente Pequeño/administración & dosificación , Animales , ADN Viral/análisis , Antígenos de Superficie de la Hepatitis B/análisis , Antígenos e de la Hepatitis B/análisis , Virus de la Hepatitis B/genética , Humanos , Concentración de Iones de Hidrógeno , Liposomas , RatonesRESUMEN
In 2010, a 39-year-old woman presented with a cystic lesion, 16 mm in diameter, in the tail of the pancreas. Regular follow-ups were conducted to monitor this lesion; its diameter was found to increase to 45 mm in 2013. Thus, the patient was admitted to our hospital for further examination and treatment. Abdominal US, abdominal contrast-enhanced CT, and MRI showed a cystic lesion of 45 mm in diameter in the tail of the pancreas, which had internal septae and mural nodules inside. EUS revealed a cyst-in-cyst-like structure, with a thickened cystic wall along the entire circumference. Thus, distal pancreatectomy and splenectomy were performed on the basis of a diagnosis of mucinous cystic neoplasm. Histopathological examination of a resected specimen showed that the lesion comprised a substantial component of red-brown tone, with adjacent cystic components. The final diagnosis was an epidermoid cyst in an intrapancreatic accessory spleen.
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Diagnóstico Diferencial , Quiste Epidérmico/diagnóstico , Neoplasias Quísticas, Mucinosas y Serosas/diagnóstico , Enfermedades del Bazo/diagnóstico , Neoplasias del Bazo/diagnóstico , Adulto , Femenino , Humanos , Imagen MultimodalRESUMEN
BACKGROUND & AIMS: Host cell lipid rafts form a scaffold required for replication of hepatitis C virus (HCV). Serine palmitoyltransferases (SPTs) produce sphingolipids, which are essential components of the lipid rafts that associate with HCV nonstructural proteins. Prevention of the de novo synthesis of sphingolipids by an SPT inhibitor disrupts the HCV replication complex and thereby inhibits HCV replication. We investigated the ability of the SPT inhibitor NA808 to prevent HCV replication in cells and mice. METHODS: We tested the ability of NA808 to inhibit SPT's enzymatic activity in FLR3-1 replicon cells. We used a replicon system to select for HCV variants that became resistant to NA808 at concentrations 4- to 6-fold the 50% inhibitory concentration, after 14 rounds of cell passage. We assessed the ability of NA808 or telaprevir to inhibit replication of HCV genotypes 1a, 1b, 2a, 3a, and 4a in mice with humanized livers (transplanted with human hepatocytes). NA808 was injected intravenously, with or without pegylated interferon alfa-2a and HCV polymerase and/or protease inhibitors. RESULTS: NA808 prevented HCV replication via noncompetitive inhibition of SPT; no resistance mutations developed. NA808 prevented replication of all HCV genotypes tested in mice with humanized livers. Intravenous NA808 significantly reduced viral load in the mice and had synergistic effects with pegylated interferon alfa-2a and HCV polymerase and protease inhibitors. CONCLUSIONS: The SPT inhibitor NA808 prevents replication of HCV genotypes 1a, 1b, 2a, 3a, and 4a in cultured hepatocytes and in mice with humanized livers. It might be developed for treatment of HCV infection or used in combination with pegylated interferon alfa-2a or HCV polymerase or protease inhibitors.
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Antivirales/farmacología , Hepacivirus/efectos de los fármacos , Hepatocitos/virología , Serina C-Palmitoiltransferasa/antagonistas & inhibidores , Replicación Viral/efectos de los fármacos , Animales , Hepacivirus/clasificación , Hepacivirus/genética , Humanos , Ratones , ARN Viral/análisisRESUMEN
Lipids are key components in the viral life cycle that affect host-pathogen interactions. In this study, we investigated the effect of HCV infection on sphingolipid metabolism, especially on endogenous SM levels, and the relationship between HCV replication and endogenous SM molecular species. We demonstrated that HCV induces the expression of the genes (SGMS1 and 2) encoding human SM synthases 1 and 2. We observed associated increases of both total and individual sphingolipid molecular species, as assessed in human hepatocytes and in the detergent-resistant membrane (DRM) fraction in which HCV replicates. SGMS1 expression had a correlation with HCV replication. Inhibition of sphingolipid biosynthesis with a hepatotropic serine palmitoyltransferase (SPT) inhibitor, NA808, suppressed HCV-RNA production while also interfering with sphingolipid metabolism. Further, we identified the SM molecular species that comprise the DRM fraction and demonstrated that these endogenous SM species interacted with HCV nonstructural 5B polymerase to enhance viral replication. Our results reveal that HCV alters sphingolipid metabolism to promote viral replication, providing new insights into the formation of the HCV replication complex and the involvement of host lipids in the HCV life cycle.
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Hepacivirus/fisiología , Hepatitis C/metabolismo , Esfingolípidos/biosíntesis , Replicación Viral/fisiología , Animales , Línea Celular Tumoral , Inhibidores Enzimáticos/farmacología , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Hepatitis C/genética , Humanos , Proteínas de la Membrana/biosíntesis , Ratones , Proteínas del Tejido Nervioso/biosíntesis , Serina C-Palmitoiltransferasa/antagonistas & inhibidores , Serina C-Palmitoiltransferasa/genética , Serina C-Palmitoiltransferasa/metabolismo , Esfingolípidos/genética , Transferasas (Grupos de Otros Fosfatos Sustitutos)/biosíntesis , Replicación Viral/efectos de los fármacosRESUMEN
INTRODUCTION AND IMPORTANCE: Acute epidural hematoma is typically managed with craniotomy. However, there are a few reports on transcatheter arterial embolization (TAE) as an adjunctive therapy. CASE PRESENTATION: A 70-year-old female with no obvious history of trauma was transported to our hospital. Computed tomography scan revealed an epidural hematoma of approximately 80 ml with a midline shift of 5 mm. We decided to perform an emergency craniotomy. However, the operating room (OR) was already occupied by a scheduled surgery and it would take 30 min to an hour to prepare it. We opted to wait for our OR, considering that, even if the patient was transferred to another hospital, it would take time for the craniotomy to commence. CLINICAL DISCUSSION: We performed TAE for the middle meningeal artery (MMA) as a palliative measure to prevent hematoma enlargement. The MMA was selectively embolized with 20 % n-butyl-2-cyanoacrylate (NBCA), resulting in no hematoma enlargement or observed complications. The criteria for endovascular treatment of acute epidural hematoma are not yet well-established. This case demonstrates the potential role of endovascular treatment for large acute epidural hematomas in carefully selected patients. CONCLUSION: If there is a time gap before craniotomy, TAE could be considered a viable option for large acute epidural hematomas as a palliative intervention before craniotomy.
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BACKGROUND: Immune checkpoint inhibitor-related pancreatic injury (ICI-PI) is a rare occurrence, which has not been reported in detail. We conducted a retrospective multicenter study to determine the clinical characteristics, risk factors, and treatment of ICI-PI. METHODS: We reviewed the medical records of patients who received ICIs for malignant tumors between April 2014 and April 2019 at 16 participating hospitals. Patients with elevated pancreatic enzymes or pancreatitis were identified and classified using the Common terminology Criteria for Adverse Events (CTCAE) ver.5.0). The number of patients with pancreatic enzyme elevation was determined and those with pancreatic enzyme elevation of ≥ grade 3 according to CTCAE ver.5.0, or pancreatitis underwent detailed analysis for ICI-PI. RESULTS: The study enrolled 1069 patients. Nineteen patients (1.8%) had ICI-PI, 5 (0.5%) of whom also had pancreatitis. Four patients had mild pancreatitis, whereas 1 patient had severe pancreatitis, culminating in death. Steroid therapy was administered to 7 of 19 patients, which led to ICI-PI improvement in 5 patients. On the other hand, ICI-PI improved in 9 of 12 patients who were not administered steroid therapy. Six of the 14 patients with ICI-PI improvement were rechallenged with ICI, and ICI-PI relapse occurred in only 1 patient (16.7%), which improved with ICI discontinuation and steroid therapy. CONCLUSIONS: ICI-PI is a rare occurrence, with a low incidence of pancreatitis, which followed a very serious course in one patient. Although the benefit of steroid therapy for ICI-PI is unclear, ICI rechallenge is acceptable after improvement of ICI-PI without pancreatitis.
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Inhibidores de Puntos de Control Inmunológico , Pancreatitis , Humanos , Inhibidores de Puntos de Control Inmunológico/efectos adversos , Páncreas , Pancreatitis/inducido químicamente , Pancreatitis/epidemiología , Estudios Retrospectivos , EsteroidesRESUMEN
BACKGROUND: Focal parenchymal atrophy and main pancreatic duct (MPD) dilatation have been identified as early signs of pancreatic ductal adenocarcinoma. However, limited evidence exists regarding their temporal progression due to previous study limitations with restricted case numbers. OBJECTIVE: To ascertain a more precise frequency assessment of suspicious pancreatic ductal adenocarcinoma findings as well as delineate the temporal progression of them. METHODS: A multicenter retrospective study was conducted on patients diagnosed with pancreatic ductal adenocarcinoma between 2015 and 2021. We included patients who had undergone at least one computed tomography (CT) scan ≥6 months before diagnosing pancreatic ductal adenocarcinoma. The temporal progression of suspicious pancreatic ductal adenocarcinoma findings on CT was investigated. RESULTS: Out of 1832 patients diagnosed with pancreatic ductal adenocarcinoma, 320 had a previous CT before their diagnosis. Suspicious pancreatic ductal adenocarcinoma findings were detected in 153 cases (47.8%), with focal parenchymal atrophy (26.6%) being the most common followed by MPD dilatation (11.3%). Focal parenchymal atrophy was the earliest detectable sign among all suspicious findings and became visible on average 2.7 years before diagnosis, and the next most common, MPD dilatation, 1.1 years before diagnosis. Other findings, such as retention cysts, were less frequent and appeared around 1 year before diagnosis. Focal parenchymal atrophy followed by MPD dilatation was observed in 10 patients but not in reverse order. Focal parenchymal atrophy was more frequently detected in the pancreatic body/tail. No significant relationship was found between the pathological pancreatic ductal adenocarcinoma differentiation or tumor stage and the time course of the CT findings. All cases of focal parenchymal atrophy progressed just prior to diagnosis, and the atrophic area was occupied by tumor at diagnosis. Main pancreatic duct dilatation continued to progress until diagnosis. CONCLUSION: This large-scale study revealed that the temporal progression of focal parenchymal atrophy is the earliest detectable sign indicating pancreatic ductal adenocarcinoma. These results provide crucial insights for early pancreatic ductal adenocarcinoma detection.
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Atrofia , Carcinoma Ductal Pancreático , Progresión de la Enfermedad , Conductos Pancreáticos , Neoplasias Pancreáticas , Tomografía Computarizada por Rayos X , Humanos , Estudios Retrospectivos , Neoplasias Pancreáticas/diagnóstico por imagen , Neoplasias Pancreáticas/patología , Neoplasias Pancreáticas/diagnóstico , Masculino , Femenino , Carcinoma Ductal Pancreático/diagnóstico por imagen , Carcinoma Ductal Pancreático/patología , Persona de Mediana Edad , Anciano , Conductos Pancreáticos/diagnóstico por imagen , Conductos Pancreáticos/patología , Factores de Tiempo , Detección Precoz del Cáncer/métodos , Dilatación Patológica/diagnóstico por imagen , Páncreas/diagnóstico por imagen , Páncreas/patología , Adulto , Anciano de 80 o más AñosRESUMEN
BACKGROUND: We recently established a monoclonal antibody (2-152a MAb) that binds to 3ß-hydroxysterol-Δ24-reductase (DHCR24) by immunizing mice with cells (RzM6-LC) persistently expressing hepatitis C virus (HCV). Here, we aimed to analyze the activity of 2-152a MAb against HCV replication and explore the molecular mechanism underlying the antiviral activity. METHODS: We characterized the effects of 2-152a MAb on HCV replication and performed a microarray analysis of antibody-treated HCV replicon cells. The molecules showing a significant change after the antibody treatment were screened to examine their relationship with HCV replication. RESULTS: The antibody had antiviral activity both in vitro and in vivo (chimeric mice). In the microarray analysis, 2-152a MAb significantly suppressed the expression of betaine/GABA transporter-1 (BGT-1) in 2 HCV replicon cell lines but not in HCV-cured cells. Silencing of BGT-1 expression by small interfering RNA (siRNA) revealed significant suppression of HCV replication and infection without cytotoxicity. Further, BGT-1 expression was significantly increased in the presence of HCV (P < .05). CONCLUSIONS: Our results suggest that 2-152a MAb suppresses HCV replication and infection through BGT-1. These findings highlight important roles of BGT-1 in HCV replication and reveal a possible target for anti-HCV therapy.
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Anticuerpos Monoclonales/uso terapéutico , Proteínas Portadoras/metabolismo , Proteínas Transportadoras de GABA en la Membrana Plasmática/metabolismo , Hepacivirus/fisiología , Hepatitis C Crónica/tratamiento farmacológico , Replicación Viral/efectos de los fármacos , Animales , Anticuerpos Monoclonales/inmunología , Línea Celular Tumoral , Proteínas Transportadoras de GABA en la Membrana Plasmática/genética , Células Hep G2 , Hepatitis C Crónica/metabolismo , Hepatitis C Crónica/virología , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Transgénicos , Proteínas del Tejido Nervioso/inmunología , Análisis de Secuencia por Matrices de Oligonucleótidos , Oxidorreductasas actuantes sobre Donantes de Grupo CH-CH/inmunología , ARN/química , ARN/genética , Interferencia de ARN , Reacción en Cadena de la Polimerasa de Transcriptasa InversaRESUMEN
BACKGROUND & AIMS: We characterized the role of 24-dehydrocholesterol reductase (DHCR24) in hepatitis C virus infection (HCV). DHCR24 is a cholesterol biosynthetic enzyme and cholesterol is a major component of lipid rafts, which is reported to play an important role in HCV replication. Therefore, we examined the potential of DHCR24 as a target for novel HCV therapeutic agents. METHODS: We examined DHCR24 expression in human hepatocytes in both the livers of HCV-infected patients and those of chimeric mice with human hepatocytes. We targeted DHCR24 with siRNA and U18666A which is an inhibitor of both DHCR24 and cholesterol synthesis. We measured the level of HCV replication in these HCV replicon cell lines and HCV infected cells. U18666A was administrated into chimeric mice with humanized liver, and anti-viral effects were assessed. RESULTS: Expression of DHCR24 was induced by HCV infection in human hepatocytes in vitro, and in human hepatocytes of chimeric mouse liver. Silencing of DHCR24 by siRNA decreased HCV replication in replicon cell lines and HCV JFH-1 strain-infected cells. Treatment with U18666A suppressed HCV replication in the replicon cell lines. Moreover, to evaluate the anti-viral effect of U18666A in vivo, we administrated U18666A with or without pegylated interferon to chimeric mice and observed an inhibitory effect of U18666A on HCV infection and a synergistic effect with interferon. CONCLUSIONS: DHCR24 is an essential host factor which augmented its expression by HCV infection, and plays a significant role in HCV replication. DHCR24 may serve as a novel anti-HCV drug target.
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Hepacivirus/fisiología , Hepatitis C/virología , Proteínas del Tejido Nervioso/metabolismo , Oxidorreductasas actuantes sobre Donantes de Grupo CH-CH/metabolismo , Replicación Viral/fisiología , Androstenos/farmacología , Androstenos/uso terapéutico , Animales , Colesterol/metabolismo , Células Hep G2 , Hepatitis C/tratamiento farmacológico , Hepatitis C/metabolismo , Humanos , Interferón-alfa/uso terapéutico , Ratones , Ratones Endogámicos BALB C , Proteínas del Tejido Nervioso/efectos de los fármacos , Proteínas del Tejido Nervioso/fisiología , Oxidorreductasas actuantes sobre Donantes de Grupo CH-CH/efectos de los fármacos , Oxidorreductasas actuantes sobre Donantes de Grupo CH-CH/fisiología , Polietilenglicoles/uso terapéutico , ARN Interferente Pequeño/farmacología , Proteínas Recombinantes/uso terapéutico , Regulación hacia ArribaRESUMEN
Hepatitis C virus (HCV) replication and infection depend on the lipid components of the cell, and replication is inhibited by inhibitors of sphingomyelin biosynthesis. We found that sphingomyelin bound to and activated genotype 1b RNA-dependent RNA polymerase (RdRp) by enhancing its template binding activity. Sphingomyelin also bound to 1a and JFH1 (genotype 2a) RdRps but did not activate them. Sphingomyelin did not bind to or activate J6CF (2a) RdRp. The sphingomyelin binding domain (SBD) of HCV RdRp was mapped to the helix-turn-helix structure (residues 231 to 260), which was essential for sphingomyelin binding and activation. Helix structures (residues 231 to 241 and 247 to 260) are important for RdRp activation, and 238S and 248E are important for maintaining the helix structures for template binding and RdRp activation by sphingomyelin. 241Q in helix 1 and the negatively charged 244D at the apex of the turn are important for sphingomyelin binding. Both amino acids are on the surface of the RdRp molecule. The polarity of the phosphocholine of sphingomyelin is important for HCV RdRp activation. However, phosphocholine did not activate RdRp. Twenty sphingomyelin molecules activated one RdRp molecule. The biochemical effect of sphingomyelin on HCV RdRp activity was virologically confirmed by the HCV replicon system. We also found that the SBD was the lipid raft membrane localization domain of HCV NS5B because JFH1 (2a) replicon cells harboring NS5B with the mutation A242C/S244D moved to the lipid raft while the wild type did not localize there. This agreed with the myriocin sensitivity of the mutant replicon. This sphingomyelin interaction is a target for HCV infection because most HCV RdRps have 241Q.
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Hepacivirus/enzimología , Hepacivirus/genética , Hepatitis C/metabolismo , ARN Polimerasa Dependiente del ARN/metabolismo , Esfingomielinas/metabolismo , Proteínas Virales/metabolismo , Activación Enzimática , Genotipo , Hepacivirus/química , Hepacivirus/fisiología , Hepatitis C/virología , Datos de Secuencia Molecular , Unión Proteica , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , ARN Polimerasa Dependiente del ARN/química , ARN Polimerasa Dependiente del ARN/genética , Especificidad de la Especie , Proteínas Virales/química , Proteínas Virales/genética , Replicación ViralRESUMEN
The lack of a small-animal model has hampered the analysis of hepatitis C virus (HCV) pathogenesis. The tupaia (Tupaia belangeri), a tree shrew, has shown susceptibility to HCV infection and has been considered a possible candidate for a small experimental model of HCV infection. However, a longitudinal analysis of HCV-infected tupaias has yet to be described. Here, we provide an analysis of HCV pathogenesis during the course of infection in tupaias over a 3-year period. The animals were inoculated with hepatitis C patient serum HCR6 or viral particles reconstituted from full-length cDNA. In either case, inoculation caused mild hepatitis and intermittent viremia during the acute phase of infection. Histological analysis of infected livers revealed that HCV caused chronic hepatitis that worsened in a time-dependent manner. Liver steatosis, cirrhotic nodules, and accompanying tumorigenesis were also detected. To examine whether infectious virus particles were produced in tupaia livers, naive animals were inoculated with sera from HCV-infected tupaias, which had been confirmed positive for HCV RNA. As a result, the recipient animals also displayed mild hepatitis and intermittent viremia. Quasispecies were also observed in the NS5A region, signaling phylogenic lineage from the original inoculating sequence. Taken together, these data suggest that the tupaia is a practical animal model for experimental studies of HCV infection.