title: The spreading process of Ehrlichia canis in macrophages is dependent on actin cytoskeleton, calcium and iron influx and lysosomal evasion.
abstract: Ehrlichia canis is an obligate intracellular microorganism and the etiologic agent of canine monocytic ehrlichiosis. The invasion process has already been described for some bacteria in this genus, such as E. muris and E. chaffeensis, and consists of four stages: adhesion, internalisation, intracellular proliferation and intercellular spreading. However, little is known about the spreading process of E. canis. The aim of this study was to analyse the role of the actin cytoskeleton, calcium, iron and lysosomes from the host cell in the spreading of E. canis in dog macrophages in vitro. Different inhibitory drugs were used: cytochalasin D (actin polymerisation inhibitor), verapamil (calcium channel blocker) and deferoxamine (iron chelator). Our results showed a decrease in the number of bacteria in infected cells treated with all drugs when compared to controls. Lysosomes in infected cells were cytochemically labelled with acid phosphatase to allow the visualisation of phagosome-lysosome fusion and were further analysed by transmission electron microscopy. Phagosome-lysosome fusion was rarely observed in vacuoles containing viable E. canis. These data suggest that the spreading process of E. canis in vitro is dependent on cellular components analysed and lysosomal evasion.
authors.affiliation: Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Avenida Pará, 1720, Umuarama, 38400-902 Uberlândia, MG, Brazil.
authors.forename: R N
authors.initials: RN
authors.lastname: Alves
authors.affiliation: Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Avenida Pará, 1720, Umuarama, 38400-902 Uberlândia, MG, Brazil. Electronic address: mal@icbim.ufu.br.
authors.forename: M A
authors.initials: MA
authors.lastname: Levenhagen
authors.affiliation: Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Avenida Pará, 1720, Umuarama, 38400-902 Uberlândia, MG, Brazil.
authors.forename: M M M D
authors.initials: MM
authors.lastname: Levenhagen
authors.affiliation: Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Avenida Pará, 1720, Umuarama, 38400-902 Uberlândia, MG, Brazil.
authors.forename: S E
authors.initials: SE
authors.lastname: Rieck
authors.affiliation: Departamento de Medicina Veterinária Preventiva e Saúde Animal, Universidade de São Paulo, Avenida Prof. Orlando Marques de Paiva, 87, Cidade Universitária, 05508-270 São Paulo, SP, Brazil.
authors.forename: M B
authors.initials: MB
authors.lastname: Labruna
authors.affiliation: Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Avenida Pará, 1720, Umuarama, 38400-902 Uberlândia, MG, Brazil.
authors.forename: M E
authors.initials: ME
authors.lastname: Beletti
mesh_terms: D008841:Actin Cytoskeleton / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D003572:Cytochalasins / Q000494:pharmacology; D003676:Deferoxamine / Q000494:pharmacology; D004283:Dog Diseases / Q000188:drug therapy / Q000276:immunology / Q000382:microbiology; D004285:Dogs; D041061:Ehrlichia canis / Q000187:drug effects / Q000254:growth & development* / Q000276:immunology; D016873:Ehrlichiosis / Q000188:drug therapy / Q000276:immunology / Q000662:veterinary; D007501:Iron / Q000378:metabolism*; D008247:Lysosomes / Q000378:metabolism / Q000382:microbiology / Q000648:ultrastructure; D008264:Macrophages / Q000378:metabolism / Q000382:microbiology* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D009000:Monocytes / Q000378:metabolism / Q000382:microbiology / Q000648:ultrastructure; D017262:Siderophores / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D003572:Cytochalasins; D017262:Siderophores; D014700:Verapamil; D007501:Iron; D003676:Deferoxamine; D002118:Calcium
keywords: Canine macrophage; Ehrlichia canis; In vitro; Spreading