title: The Acinetobacter baumannii Omp33-36 porin is a virulence factor that induces apoptosis and modulates autophagy in human cells.
abstract: Acinetobacter baumannii is an extracellular opportunistic human pathogen that is becoming increasingly problematic in hospitals. In the present study, we demonstrate that the A. baumannii Omp 33- to 36-kDa protein (Omp33-36) is a porin that acts as a channel for the passage of water. The protein is found on the cell surface and is released along with other porins in the outer membrane vesicles (OMVs). In immune and connective cell tissue, this protein induced apoptosis by activation of caspases and modulation of autophagy, with the consequent accumulation of p62/SQSTM1 (sequestosome 1) and LC3B-II (confirmed by use of autophagy inhibitors). Blockage of autophagy enables the bacterium to persist intracellularly (inside autophagosomes), with the subsequent development of cytotoxicity. Finally, we used macrophages and a mouse model of systemic infection to confirm that Omp33-36 is a virulence factor in A. baumannii. Overall, the study findings show that Omp33-36 plays an important role in the pathogenesis of A. baumannii infections.
authors.affiliation: Department of Microbiology, Complejo Hospitalario Universitario A Coruña-INIBIC, La Coruña, Spain.
authors.forename: Carlos
authors.initials: C
authors.lastname: Rumbo
authors.affiliation: Department of Microbiology, Complejo Hospitalario Universitario A Coruña-INIBIC, La Coruña, Spain ma.del.mar.tomas.carmona@sergas.es german.bou.arevalo@sergas.es.
authors.forename: María
authors.initials: M
authors.lastname: Tomás
authors.affiliation: Department of Microbiology, Complejo Hospitalario Universitario A Coruña-INIBIC, La Coruña, Spain.
authors.forename: Esteban
authors.initials: E
authors.lastname: Fernández Moreira
authors.affiliation: Department of Microbiology, Complejo Hospitalario Universitario A Coruña-INIBIC, La Coruña, Spain.
authors.forename: Nelson Cruz
authors.initials: NC
authors.lastname: Soares
authors.affiliation: CEBAS-CSIC, Madrid, Spain.
authors.forename: Micaela
authors.initials: M
authors.lastname: Carvajal
authors.affiliation: CIB-CSIC, Madrid, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Santillana
authors.affiliation: Department of Microbiology, Complejo Hospitalario Universitario A Coruña-INIBIC, La Coruña, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Beceiro
authors.affiliation: CIB-CSIC, Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Romero
authors.affiliation: Department of Microbiology, Complejo Hospitalario Universitario A Coruña-INIBIC, La Coruña, Spain ma.del.mar.tomas.carmona@sergas.es german.bou.arevalo@sergas.es.
authors.forename: Germán
authors.initials: G
authors.lastname: Bou
mesh_terms: D000151:Acinetobacter Infections / Q000382:microbiology; D040981:Acinetobacter baumannii; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001343:Autophagy / Q000187:drug effects*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D053938:DNA Fragmentation; D006801:Humans; D008264:Macrophages / Q000382:microbiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018272:Porins / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D018272:Porins; D037521:Virulence Factors