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Susan L. Uprichard, PhD Director of Hepatology Research Loyola University Medical Center Department of Medicine Section of Hepatology HepNet 2013 HCV Virology
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Approximately 170 million people worldwide are infected with HCV World Health Organization. Hepatitis C - Global Surveillance Update <1% 1 - 2.4% 2.5 - 4.9% 5 - 10% >10% n/a
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Acute infection – typically asymptomatic The majority of those who become infected remain chronically infected persistent hepatitis steatosis liver cirrhosis hepatocellular carcinoma HCV Infection TrichromeStainedFibrosis Picture from: Picture from: Dr. Guzman Dr. Guzman
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No preventative vaccine Only a fraction of patients respond to available IFN-based therapies limited efficacy expensiveadherence adverse side effects Many do not know they are infected Unknown who will develop progressive disease Unknown who will respond to therapy HCV Infection
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No preventative vaccine Only a fraction of patients respond to available IFN-based therapies limited efficacy expensive adverse side effects Many do not know they are infected Unknown who will develop progressive disease Unknown who will respond to therapy HCV Infection Better understanding of HCV and the host factors that determine outcome and treatment response is needed to improve treatment options
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1975 Description of non-A, non-B hepatitis 1989 Identification of HCV HCV Timeline Ability to screen blood 15 years
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Family: Flaviviridae (enveloped, positive-strand RNA viruses) HCV Genome: contains a single ORF that encodes a polyprotein (~3011aa) contains a single ORF that encodes a polyprotein (~3011aa) Translated in the cytoplasm by the host cell Translated in the cytoplasm by the host cell Polyprotein processed by host & viral proteases Polyprotein processed by host & viral proteases Identification of possible HCV antiviral targets (protease/polymerase) Identification of possible HCV antiviral targets (protease/polymerase) RNA= 9.6kb HCV Virology
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1975 Description of non-A, non-B hepatitis 1989 Identification of HCV 1998 IFN / ribavirin combination therapy 1999 Replicon system HCV Timeline Ability to screen blood 1997 Infectious clone in chimpanzees 10 years
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Recombinant HCV RNA containing a selection marker How replicons work:Introduce RNA into cell Viral replication proteins are made Viral proteins replicate the RNA. HCV Replicons
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Using the selection marker could select for cells that replicate the replicon HCV Replicons Allowed for robust antiviral drug screening (protease / polymerase inhibitors)
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1975 Description of non-A, non-B hepatitis 1989 Identification of HCV 1998 IFN / ribavirin combination therapy 2005 Infectious HCV cell culture system 1999 Replicon system HCV Timeline Ability to screen blood 2012 Protease inhibitors Polymerase inhibitors 1997 Infectious clone in chimpanzees
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HCV Infection System
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1975 Description of non-A, non-B hepatitis 1989 Identification of HCV 1998 IFN / ribavirin combination therapy 2005 Infectious HCV cell culture system 2013 1999 Replicon system HCV Timeline HCV Mouse Model Ability to screen blood 2012 Protease inhibitors Polymerase inhibitors Entry inhibitors Host factor inhibitors 1997 Infectious clone in chimpanzees
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HCV Life Cycle
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From Ralf Bartenschlager
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HOST FACTORS INVOLVED IN HCV ENTRY
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Niemann-Pick C1 Like 1 Protein ( NPC1L1 ) SSD 13 trans-membrane cell surface cholesterol transporter Altmann, et al. (2004) - Cellular cholesterol absorption and homeostasis –NPC1L1 takes up free cholesterol into cells via vesicular endocytosis (clathrin) In most species, expression restricted to the enterocytes However - humans & chimpanzees, it is also abundant on hepatocytes 145 kDa LEL1 LEL2 LEL3
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HOST FACTORS SERVE AS POTENTIAL ANTIVIRAL TARGETS
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HCV seroprevalence across ezetimibe use HCV Positive (N=276) HCV Negative (N=15337) On ezetimibe 0.2%99.8% Not on ezetimibe 1.7%98.3% P-value: 0.02 (Adjusted sampling & design corrections applied for analyses)
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WHAT DO HOST FACTORS HAVE TO TEACH US ABOUT HCV?
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