scholarly journals Organ system view of the hepatic innate immunity in HCV infection

2016 ◽  
Vol 88 (12) ◽  
pp. 2025-2037 ◽  
Author(s):  
Bo-Ram Bang ◽  
Sandra Elmasry ◽  
Takeshi Saito
Keyword(s):  
Innate Immunity ◽  
Organ System ◽  
Hcv Infection ◽  
System View ◽  
Hepatic Innate Immunity

scholarly journals Dysregulated liver lipid metabolism and innate immunity associated with hepatic steatosis in neonatal BBdp rats and NOD mice

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
D. Serrano ◽  
J. A. Crookshank ◽  
B. S. Morgan ◽  
R. W. Mueller ◽  
M.-F. Paré ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Lipid Metabolism ◽  
Hepatic Steatosis ◽  
Liver Lipid ◽  
Nod Mice ◽  
Gene Signature ◽  
Enhanced Expression ◽  
Liver Lipid Metabolism ◽  
Hepatic Innate Immunity ◽  
Lipid Metabolism Genes

Abstract In a previous study we reported that prediabetic rats have a unique gene signature that was apparent even in neonates. Several of the changes we observed, including enhanced expression of pro-inflammatory genes and dysregulated UPR and metabolism genes were first observed in the liver followed by the pancreas. In the present study we investigated further early changes in hepatic innate immunity and metabolism in two models of type 1 diabetes (T1D), the BBdp rat and NOD mouse. There was a striking increase in lipid deposits in liver, particularly in neonatal BBdp rats, with a less striking but significant increase in neonatal NOD mice in association with dysregulated expression of lipid metabolism genes. This was associated with a decreased number of extramedullary hematopoietic clusters as well as CD68+ macrophages in the liver of both models. In addition, PPARɣ and phosphorylated AMPKα protein were decreased in neonatal BBdp rats. BBdp rats displayed decreased expression of antimicrobial genes in neonates and decreased M2 genes at 30 days. This suggests hepatic steatosis could be a common early feature in development of T1D that impacts metabolic homeostasis and tolerogenic phenotype in the prediabetic liver.

scholarly journals Chaperone-Mediated Autophagy in the Liver: Good or Bad?

Cells ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1308 ◽  
Author(s):  
Srikanta Dash ◽  
Yucel Aydin ◽  
Krzysztof Moroz
Keyword(s):  
Cellular Stress ◽  
Hcv Infection ◽  
Liver Disease Progression ◽  
Cellular Autophagy ◽  
Therapeutic Development ◽  
Metabolic Conditions ◽  
Hepatic Innate Immunity ◽  
Viral Etiologies ◽  
Cellular Components ◽  
Chaperone Mediated Autophagy

Hepatitis C virus (HCV) infection triggers autophagy processes, which help clear out the dysfunctional viral and cellular components that would otherwise inhibit the virus replication. Increased cellular autophagy may kill the infected cell and terminate the infection without proper regulation. The mechanism of autophagy regulation during liver disease progression in HCV infection is unclear. The autophagy research has gained a lot of attention recently since autophagy impairment is associated with the development of hepatocellular carcinoma (HCC). Macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA) are three autophagy processes involved in the lysosomal degradation and extracellular release of cytosolic cargoes under excessive stress. Autophagy processes compensate for each other during extreme endoplasmic reticulum (ER) stress to promote host and microbe survival as well as HCC development in the highly stressed microenvironment of the cirrhotic liver. This review describes the molecular details of how excessive cellular stress generated during HCV infection activates CMA to improve cell survival. The pathological implications of stress-related CMA activation resulting in the loss of hepatic innate immunity and tumor suppressors, which are most often observed among cirrhotic patients with HCC, are discussed. The oncogenic cell programming through autophagy regulation initiated by a cytoplasmic virus may facilitate our understanding of HCC mechanisms related to non-viral etiologies and metabolic conditions such as uncontrolled type II diabetes. We propose that a better understanding of how excessive cellular stress leads to cancer through autophagy modulation may allow therapeutic development and early detection of HCC.

Leptin and hepatic innate immunity

2001 ◽  
Vol 120 (5) ◽  
pp. A26-A26
Author(s):  
S YANG ◽  
H LIN ◽  
R SCHWENK ◽  
U KRYTCH ◽  
A DIEHL
Keyword(s):  
Innate Immunity ◽  
Hepatic Innate Immunity

T1619 Alteration in Hepatic Innate Immunity Triggers Hepatic Regeneration Failure in Obese and Diabetic Kk-aY Mice

2009 ◽  
Vol 136 (5) ◽  
pp. A-850
Author(s):  
Tomonori Aoyama ◽  
Kenichi Ikejima ◽  
Kazuyoshi Kon ◽  
Hisafumi Yamagata ◽  
Shunhei Yamashina ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Hepatic Regeneration ◽  
Regeneration Failure ◽  
Hepatic Innate Immunity ◽  
Ay Mice

scholarly journals Pathogen-Associated Molecular Pattern Recognition of Hepatitis C Virus Transmitted/Founder Variants by RIG-I Is Dependent on U-Core Length

2015 ◽  
Vol 89 (21) ◽  
pp. 11056-11068 ◽  
Author(s):  
Alison Kell ◽  
Mark Stoddard ◽  
Hui Li ◽  
Joe Marcotrigiano ◽  
George M. Shaw ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Acute Infection ◽  
Innate Immune ◽  
Hcv Infection ◽  
Immune Signaling ◽  
Molecular Pattern ◽  
Innate Immune Signaling ◽  
Acute Hcv

ABSTRACTDespite the introduction of direct-acting antiviral (DAA) drugs against hepatitis C virus (HCV), infection remains a major public health concern because DAA therapeutics do not prevent reinfection and patients can still progress to chronic liver disease. Chronic HCV infection is supported by a variety of viral immune evasion strategies, but, remarkably, 20% to 30% of acute infections spontaneously clear prior to development of adaptive immune responses, thus implicating innate immunity in resolving acute HCV infection. However, the virus-host interactions regulating acute infection are unknown. Transmission of HCV involves one or a few transmitted/founder (T/F) variants. In infected hepatocytes, the retinoic acid-inducible gene I (RIG-I) protein recognizes 5′ triphosphate (5′ppp) of the HCV RNA and a pathogen-associated molecular pattern (PAMP) motif located within the 3′ untranslated region consisting of poly-U/UC. PAMP binding activates RIG-I to induce innate immune signaling and type 1 interferon antiviral defenses. HCV poly-U/UC sequences can differ in length and complexity, suggesting that PAMP diversity in T/F genomes could regulate innate immune control of acute HCV infection. Using 14 unique poly-U/UC sequences from HCV T/F genomes recovered from acute-infection patients, we tested whether RIG-I recognition and innate immune activation correlate with PAMP sequence characteristics. We show that T/F variants are recognized by RIG-I in a manner dependent on length of the U-core motif of the poly-U/UC PAMP and are recognized by RIG-I to induce innate immune responses that restrict acute infection. PAMP recognition of T/F HCV variants by RIG-I may therefore impart innate immune signaling and HCV restriction to impact acute-phase-to-chronic-phase transition.IMPORTANCERecognition of nonself molecular patterns such as those seen with viral nucleic acids is an essential step in triggering the immune response to virus infection. Innate immunity is induced by hepatitis C virus infection through the recognition of viral RNA by the cellular RIG-I protein, where RIG-I recognizes a poly-uridine/cytosine motif in the viral genome. Variation within this motif may provide an immune evasion strategy for transmitted/founder viruses during acute infection. Using 14 unique poly-U/UC sequences from HCV T/F genomes recovered from acutely infected HCV patients, we demonstrate that RIG-I binding and activation of innate immunity depend primarily on the length of the uridine core within this motif. T/F variants found in acute infection contained longer U cores within the motif and could activate RIG-I and induce innate immune signaling sufficient to restrict viral infection. Thus, recognition of T/F variants by RIG-I could significantly impact the transition from acute to chronic infection.

scholarly journals Developmental regulation of myeloerythroid progenitor function by the Lin28b–let-7–Hmga2 axis

2016 ◽  
Vol 213 (8) ◽  
pp. 1497-1512 ◽  
Author(s):  
R. Grant Rowe ◽  
Leo D. Wang ◽  
Silvia Coma ◽  
Areum Han ◽  
Ronald Mathieu ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Detailed Analysis ◽  
Developmental Regulation ◽  
Organ System ◽  
Developmental Timing ◽  
Intrauterine Environment ◽  
Genetic Switch ◽  
Hematopoietic System ◽  
Prenatal Growth ◽  
Ectopic Activation

For appropriate development, tissue and organ system morphogenesis and maturation must occur in synchrony with the overall developmental requirements of the host. Mistiming of such developmental events often results in disease. The hematopoietic system matures from the fetal state, characterized by robust erythrocytic output that supports prenatal growth in the hypoxic intrauterine environment, to the postnatal state wherein granulocytes predominate to provide innate immunity. Regulation of the developmental timing of these myeloerythroid states is not well understood. In this study, we find that expression of the heterochronic factor Lin28b decreases in common myeloid progenitors during hematopoietic maturation to adulthood in mice. This decrease in Lin28b coincides with accumulation of mature let-7 microRNAs, whose biogenesis is regulated by Lin28 proteins. We find that inhibition of let-7 in the adult hematopoietic system recapitulates fetal erythroid-dominant hematopoiesis. Conversely, deletion of Lin28b or ectopic activation of let-7 microRNAs in the fetal state induces a shift toward adult-like myeloid-dominant output. Furthermore, we identify Hmga2 as an effector of this genetic switch. These studies provide the first detailed analysis of the roles of endogenous Lin28b and let-7 in the timing of hematopoietic states during development.

scholarly journals Hepatitis C Virus Evasion from RIG-I-Dependent Hepatic Innate Immunity

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Helene Minyi Liu ◽  
Michael Gale
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Intracellular Signaling ◽  
Innate Immune ◽  
Hcv Infection ◽  
Viral Pathogen ◽  
Infected Hepatocyte ◽  
Interferon Stimulated Genes ◽  
Hepatic Innate Immunity ◽  
Chronic Hcv

Exposure to hepatitis C virus (HCV) usually results in persistent infection that often develops into chronic liver disease. Interferon-alpha (IFN) treatment comprises the foundation of current approved therapy for chronic HCV infection but is limited in overall efficacy. IFN is a major effector of innate antiviral immunity and is naturally produced in response to viral infection when viral pathogen-associated molecular patterns (PAMPs) are recognized as nonself and are bound by cellular pathogen recognition receptors (PRRs), including Toll-like receptors (TLRs) and the RIG-I-like receptors (RLRs). Within hepatocytes, RIG-I is a major PRR of HCV infection wherein PAMP interactions serve to trigger intracellular signaling cascades in the infected hepatocyte to drive IFN production and the expression of interferon-stimulated genes (ISGs). ISGs function to limit virus replication, modulate the immune system, and to suppress virus spread. However, studies of HCV-host interactions have revealed several mechanisms of innate immune regulation and evasion that feature virus control of PRR signaling and regulation of hepatic innate immune programs that may provide a molecular basis for viral persistence.

scholarly journals Neuralized E3 Ubiquitin Protein Ligase 3 Is an Inducible Antiviral Effector That Inhibits Hepatitis C Virus Assembly by Targeting Viral E1 Glycoprotein

2018 ◽  
Vol 92 (21) ◽  
Author(s):  
Yanan Zhao ◽  
Xuezhi Cao ◽  
Mingzhe Guo ◽  
Xuesong Wang ◽  
Tao Yu ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Hepatitis C ◽  
Envelope Glycoprotein ◽  
Biological Function ◽  
Rna Viruses ◽  
Innate Immune ◽  
Hcv Infection ◽  
Ubiquitin Protein Ligase ◽  
Host Innate Immunity ◽  
Insight Into

ABSTRACTHepatitis C virus (HCV) infection is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. HCV can be sensed by host innate immunity to induce expression of interferons (IFNs) and a number of antiviral effectors. In this study, we found HCV infection induced the expression of neuralized E3 ubiquitin protein ligase 3 (NEURL3), a putative E3 ligase, in a manner that requires the involvement of innate immune sensing but is independent of the IFN action. Furthermore, we showed that NEURL3 inhibited HCV infection while it had little effect on other RNA viruses, including Zika virus (ZIKV), dengue virus (DENV), and vesicular stomatitis virus (VSV). Mechanistic studies demonstrated that NEURL3 inhibited HCV assembly by directly binding HCV envelope glycoprotein E1 to interfere with the E1/E2 heterodimerization, an important prerequisite for virion morphogenesis. Finally, we showed that knockout of NEURL3 significantly enhanced HCV infection. In summary, we identified NEURL3 as a novel inducible antiviral host factor that suppresses HCV assembly. Our results not only shed new insight into how host innate immunity acts against HCV but also revealed a new important biological function for NEURL3.IMPORTANCEThe exact biological function of NEURL3, a putative E3 ligase, remains largely unknown. In this study, we found that NEURL3 could be upregulated upon HCV infection in a manner dependent on pattern recognition receptor-mediated innate immune response. NEURL3 inhibits HCV assembly by directly binding viral E1 envelope glycoprotein to disrupt its interaction with E2, an action that requires its Neuralized homology repeat (NHR) domain but not the RING domain. Furthermore, we found that NEURL3 has a pangenotypic anti-HCV activity and interacts with E1 of genotypes 2a, 1b, 3a, and 6a but does not inhibit other closely related RNA viruses, such as ZIKV, DENV, and VSV. To our knowledge, our study is the first report to demonstrate that NEURL3 functions as an antiviral host factor. Our results not only shed new insight into how host innate immunity acts against HCV, but also revealed a new important biological function for NEURL3.

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