title: Inhibition of dendritic cell apoptosis by Leishmania mexicana amastigotes.
abstract: Macrophages (Mφ) and dendritic cells are the major target cell populations of the obligate intracellular parasite Leishmania. Inhibition of host cell apoptosis is a strategy employed by multiple pathogens to ensure their survival in the infected cell. Leishmania promastigotes have been shown to protect Mφ, neutrophils, and dendritic cells from both natural and induced apoptosis. Nevertheless, the effect of the infection with Leishmania amastigotes in the apoptosis of these cell populations has not been established, which results are very important since amastigotes persist in cells for many days and are responsible for sustaining infection in the host. As shown in this study, apoptosis of monocyte-derived dendritic cells (moDC) induced by treatment with camptothecin was downregulated by infection with L. mexicana amastigotes from 42.48 to 36.92% as detected by Annexin-V binding to phosphatidylserine. Also, the infection of moDC with L. mexicana amastigotes diminished the fragmentation of DNA as detected by terminal deoxynucleotidyl transferase-mediated fluorescein-dUTP nick end labeling assay, and changes in cell morphology were analyzed by electron microscopy. The observed antiapoptotic effect was found to be associated with an 80% reduction in the presence of active caspase-3 in infected moDC. The capacity of L. mexicana amastigotes to delay apoptosis induction in the infected moDC may have implications for Leishmania pathogenesis by favoring the invasion of its host and the persistence of the parasite in the infected cells.
authors: Departamento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Dr. Balmis 148 Col. Doctores, México D.F., 06726, Mexico. lgutierr@unam.mx
authors: Laila
authors: L
authors: Gutiérrez-Kobeh
authors: Eleané
authors: E
authors: de Oyarzabal
authors: Jesús
authors: J
authors: Argueta
authors: Arturo
authors: A
authors: Wilkins
authors: Norma
authors: N
authors: Salaiza
authors: Edith
authors: E
authors: Fernández
authors: Oliver
authors: O
authors: López
authors: Magdalena
authors: M
authors: Aguirre
authors: Ingeborg
authors: I
authors: Becker
mesh_terms: D000818:Animals; D017304:Annexin A5 / Q000032:analysis; D017209:Apoptosis; D003713:Dendritic Cells / Q000276:immunology* / Q000469:parasitology*; D004583:Electrons; D006801:Humans; D057131:Immune Evasion; D020287:In Situ Nick-End Labeling; D007894:Leishmania mexicana / Q000276:immunology* / Q000472:pathogenicity
chemical_list: D017304:Annexin A5