title: Long-term live imaging reveals cytosolic immune responses of host hepatocytes against Plasmodium infection and parasite escape mechanisms.
abstract: Plasmodium parasites are transmitted by Anopheles mosquitoes to the mammalian host and actively infect hepatocytes after passive transport in the bloodstream to the liver. In their target host hepatocyte, parasites reside within a parasitophorous vacuole (PV). In the present study it was shown that the parasitophorous vacuole membrane (PVM) can be targeted by autophagy marker proteins LC3, ubiquitin, and SQSTM1/p62 as well as by lysosomes in a process resembling selective autophagy. The dynamics of autophagy marker proteins in individual Plasmodium berghei-infected hepatocytes were followed by live imaging throughout the entire development of the parasite in the liver. Although the host cell very efficiently recognized the invading parasite in its vacuole, the majority of parasites survived this initial attack. Successful parasite development correlated with the gradual loss of all analyzed autophagy marker proteins and associated lysosomes from the PVM. However, other autophagic events like nonselective canonical autophagy in the host cell continued. This was indicated as LC3, although not labeling the PVM anymore, still localized to autophagosomes in the infected host cell. It appears that growing parasites even benefit from this form of nonselective host cell autophagy as an additional source of nutrients, as in host cells deficient for autophagy, parasite growth was retarded and could partly be rescued by the supply of additional amino acid in the medium. Importantly, mouse infections with P. berghei sporozoites confirmed LC3 dynamics, the positive effect of autophagy activation on parasite growth, and negative effects upon autophagy inhibition.
authors.affiliation: b Molecular Parasitology; Bernhard Nocht Institute for Tropical Medicine ; Hamburg , Germany.
authors.forename: Monica
authors.initials: M
authors.lastname: Prado
authors.affiliation: a Institute of Cell Biology; University of Bern ; Bern , Switzerland.
authors.forename: Nina
authors.initials: N
authors.lastname: Eickel
authors.affiliation: a Institute of Cell Biology; University of Bern ; Bern , Switzerland.
authors.forename: Mariana
authors.initials: M
authors.lastname: De Niz
authors.affiliation: b Molecular Parasitology; Bernhard Nocht Institute for Tropical Medicine ; Hamburg , Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Heitmann
authors.affiliation: a Institute of Cell Biology; University of Bern ; Bern , Switzerland.
authors.forename: Carolina
authors.initials: C
authors.lastname: Agop-Nersesian
authors.affiliation: a Institute of Cell Biology; University of Bern ; Bern , Switzerland.
authors.forename: Rahel
authors.initials: R
authors.lastname: Wacker
authors.affiliation: a Institute of Cell Biology; University of Bern ; Bern , Switzerland.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Schmuckli-Maurer
authors.affiliation: a Institute of Cell Biology; University of Bern ; Bern , Switzerland.
authors.forename: Reto
authors.initials: R
authors.lastname: Caldelari
authors.affiliation: c Center of Infectious Diseases; Leiden University Medical Center ; Leiden , The Netherlands.
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Janse
authors.affiliation: c Center of Infectious Diseases; Leiden University Medical Center ; Leiden , The Netherlands.
authors.forename: Shahid M
authors.initials: SM
authors.lastname: Khan
authors.affiliation: d Infectious Disease Epidemiology; Bernhard Nocht Institute for Tropical Medicine ; Hamburg , Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: May
authors.affiliation: e Molecular Medicine; Bernhard Nocht Institute for Tropical Medicine ; Hamburg , Germany.|f Institute of Tropical Medicine; Eberhard-Karls University ; Tübingen , Germany.
authors.forename: Christian G
authors.initials: CG
authors.lastname: Meyer
authors.affiliation: a Institute of Cell Biology; University of Bern ; Bern , Switzerland.
authors.forename: Volker T
authors.initials: VT
authors.lastname: Heussler
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D001343:Autophagy; D015415:Biomarkers / Q000378:metabolism; D003600:Cytosol / Q000276:immunology*; D037161:Galectins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000276:immunology* / Q000469:parasitology / Q000648:ultrastructure; D006801:Humans; D021621:Imaging, Three-Dimensional; D057131:Immune Evasion; D007109:Immunity; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D008018:Life Cycle Stages; D008099:Liver / Q000469:parasitology; D008247:Lysosomes / Q000378:metabolism / Q000648:ultrastructure; D008288:Malaria / Q000276:immunology* / Q000469:parasitology; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D010271:Parasites / Q000254:growth & development / Q000276:immunology* / Q000472:pathogenicity / Q000648:ultrastructure; D010962:Plasmodium berghei / Q000254:growth & development / Q000472:pathogenicity* / Q000648:ultrastructure; D000071456:Sequestosome-1 Protein; D034101:Sporozoites / Q000502:physiology / Q000648:ultrastructure; D016019:Survival Analysis; D013997:Time Factors; D025801:Ubiquitin / Q000378:metabolism; D054875:Ubiquitination; D014617:Vacuoles / Q000378:metabolism / Q000648:ultrastructure; D014774:Virulence
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015415:Biomarkers; D037161:Galectins; D006360:Heat-Shock Proteins; C480860:Map1lc3b protein, mouse; D008869:Microtubule-Associated Proteins; D000071456:Sequestosome-1 Protein; C101343:Sqstm1 protein, mouse; D025801:Ubiquitin
keywords: LC3; Plasmodium liver-stage; cytosolic immune response; long-term live imaging; malaria; selective autophagy; ubiquitin