title: Several Human Liver Cell Expressed Apolipoproteins Complement HCV Virus Production with Varying Efficacy Conferring Differential Specific Infectivity to Released Viruses.
abstract: Apolipoprotein E (ApoE), an exchangeable apolipoprotein, is necessary for production of infectious Hepatitis C virus (HCV) particles. However, ApoE is not the only liver-expressed apolipoprotein and the role of other apolipoproteins for production of infectious HCV progeny is incompletely defined. Therefore, we quantified mRNA expression of human apolipoproteins in primary human hepatocytes. Subsequently, cDNAs encoding apolipoproteins were expressed in 293T/miR-122 cells to explore if they complement HCV virus production in cells that are non-permissive due to limiting endogenous levels of human apolipoproteins. Primary human hepatocytes expressed high mRNA levels of ApoA1, A2, C1, C3, E, and H. ApoA4, A5, B, D, F, J, L1, L2, L3, L4, L6, M, and O were expressed at intermediate levels, and C2, C4, and L5 were not detected. All members of the ApoA and ApoC family of lipoproteins complemented HCV virus production in HCV transfected 293T/miR-122 cells, albeit with significantly lower efficacy compared with ApoE. In contrast, ApoD expression did not support production of infectious HCV. Specific infectivity of released particles complemented with ApoA family members was significantly lower compared with ApoE. Moreover, the ratio of extracellular to intracellular infectious virus was significantly higher for ApoE compared to ApoA2 and ApoC3. Since apolipoproteins complementing HCV virus production share amphipathic alpha helices as common structural features we altered the two alpha helices of ApoC1. Helix breaking mutations in both ApoC1 helices impaired virus assembly highlighting a critical role of alpha helices in apolipoproteins supporting HCV assembly. In summary, various liver expressed apolipoproteins with amphipathic alpha helices complement HCV virus production in human non liver cells. Differences in the efficiency of virus assembly, the specific infectivity of released particles, and the ratio between extracellular and intracellular infectivity point to distinct characteristics of these apolipoproteins that influence HCV assembly and cell entry. This will guide future research to precisely pinpoint how apolipoproteins function during virus assembly and cell entry.
authors.affiliation: Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Hueging
authors.affiliation: Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany.
authors.forename: Romy
authors.initials: R
authors.lastname: Weller
authors.affiliation: Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany.
authors.forename: Mandy
authors.initials: M
authors.lastname: Doepke
authors.affiliation: Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany.
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Vieyres
authors.affiliation: Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Todt
authors.affiliation: Institute of Virology, Hannover Medical School, Hannover, Germany.
authors.forename: Benno
authors.initials: B
authors.lastname: Wölk
authors.affiliation: Department of General, Visceral and Transplant Surgery, Hannover Medical School, Hannover, Germany; Integrated Research and Treatment Center Transplantation (IFB-Tx), Hannover Medical School, Hannover, Germany; German Centre for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Hannover, Germany.
authors.forename: Florian W R
authors.initials: FW
authors.lastname: Vondran
authors.affiliation: Research Group Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Geffers
authors.affiliation: Institute for Medical Informatics and Biometry, Medical Faculty, Technische Universität Dresden, Dresden, Germany.
authors.forename: Chris
authors.initials: C
authors.lastname: Lauber
authors.affiliation: Institute for Medical Informatics and Biometry, Medical Faculty, Technische Universität Dresden, Dresden, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Kaderali
authors.affiliation: Institut de Biologie et Chimie des Protéines, Bases Moléculaires et Structurales des Systèmes Infectieux, UMR 5086, CNRS, Labex Ecofect, University of Lyon, Lyon, France.
authors.forename: François
authors.initials: F
authors.lastname: Penin
authors.affiliation: Institute of Experimental Virology, TWINCORE, Centre for Experimental and Clinical Infection Research, Hannover, Germany; German Centre for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Hannover, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Pietschmann
mesh_terms: D001053:Apolipoproteins / Q000502:physiology*; D002460:Cell Line; D016174:Hepacivirus / Q000472:pathogenicity / Q000502:physiology*; D022781:Hepatocytes / Q000378:metabolism*; D006801:Humans; D014774:Virulence; D014779:Virus Replication / Q000502:physiology*
chemical_list: D001053:Apolipoproteins