title: A 32-kilodalton hydrolase plays an important role in Paracoccidioides brasiliensis adherence to host cells and influences pathogenicity.
abstract: One of the most crucial events during infection with the dimorphic fungus Paracoccidioides brasiliensis is adhesion to pulmonary epithelial cells, a pivotal step in the establishment of disease. In this study, we have evaluated the relevance of a 32-kDa protein, a putative adhesion member of the haloacid dehalogenase (HAD) superfamily of hydrolases, in the virulence of this fungus. Protein sequence analyses have supported the inclusion of PbHad32p as a hydrolase and have revealed a conserved protein only among fungal dimorphic and filamentous pathogens that are closely phylogenetically related. To evaluate its role during the host-pathogen interaction, we have generated mitotically stable P. brasiliensis HAD32 (PbHAD32) antisense RNA (aRNA) strains with consistently reduced gene expression. Knockdown of PbHAD32 did not alter cell vitality or viability but induced morphological alterations in yeast cells. Moreover, yeast cells with reduced PbHAD32 expression were significantly affected in their capacity to adhere to human epithelial cells and presented decreased virulence in a mouse model of infection. These data support the hypothesis that PbHad32p binds to extracellular matrix (ECM) proteins and modulates the initial immune response for evasion of host defenses. Our findings point to PbHAD32 as a novel virulence factor active during the initial interaction with host cells in P. brasiliensis.
authors.affiliation: Instituto de Biología, Universidad de Antioquia, Medellín, Colombia. orvillehr@hotmail.com
authors.forename: Orville
authors.initials: O
authors.lastname: Hernández
authors.forename: Agostinho J
authors.initials: AJ
authors.lastname: Almeida
authors.forename: Angel
authors.initials: A
authors.lastname: Gonzalez
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Garcia
authors.forename: Diana
authors.initials: D
authors.lastname: Tamayo
authors.forename: Luz Elena
authors.initials: LE
authors.lastname: Cano
authors.forename: Angela
authors.initials: A
authors.lastname: Restrepo
authors.forename: Juan G
authors.initials: JG
authors.lastname: McEwen
mesh_terms: D000818:Animals; D002448:Cell Adhesion; D002460:Cell Line; D019743:Chemokines, CXC; D016207:Cytokines / Q000096:biosynthesis / Q000502:physiology; D020869:Gene Expression Profiling; D055785:Gene Knockdown Techniques; D054884:Host-Pathogen Interactions / Q000502:physiology; D006801:Humans; D006867:Hydrolases / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010228:Paracoccidioides / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology; D010229:Paracoccidioidomycosis / Q000382:microbiology*; D020545:Respiratory Mucosa / Q000382:microbiology
chemical_list: D019743:Chemokines, CXC; C118893:Cxcl15 protein, mouse; D016207:Cytokines; D006867:Hydrolases; C034507:2-haloacid dehalogenase