title: Blocking the expression of syntaxin 4 interferes with initial phagocytosis of Brucella melitensis in macrophages.
abstract: Brucella melitensis is the Brucella species most frequently associated with brucellosis in humans. It is also the causative agent of the disease in goats and other ruminants. Although significant aspects of the pathogenesis of infection by this intracellular pathogen have been clarified, several events during invasion of host cells remain to be elucidated. In this study, infections of human macrophages from the THP-1 monocyte cell line were conducted with B. melitensis Bm133 wild-type strain and a strain of Salmonella serovar Enteritidis as a control. A multiplicity of infection of 100 was used in trials focused on defining the relative expression of syntaxin 4 (STX4), a soluble N-ethylmaleimide-sensitive factor attachment protein receptor, in the early events of phagocytosis (at 15, 30, 45, and 60 min). Immunoblot assays were also done to visualize expression of the protein in cells infected with either bacterial strain. The expression of STX4 was not significantly different in cells infected with B. melitensis strain Bm133 compared to that observed in cells infected with S. Enteritidis. When the expression of STX4 mRNA was inhibited with short or small interfering, or silencing, RNA in the THP-1 cells, the survival of B. melitensis was significantly reduced at time 0, when gentamicin treatment of cultures was begun (after 1 h of phagocytosis), and also at 2 h and 12 h after infection.
authors: Laboratorio de Microbiología Molecular, Departamento de Microbiología e Inmunología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Av. Universidad 3000, Circuito Exterior s/n, CU, Distrito Federal 04510, México (Castañeda-Ramírez, González-Rodríguez, Hernández-Pineda, Verdugo-Rodríguez); Departamento de Zootecnia, Universidad Autónoma Chapingo, Texcoco, México (Castañeda-Ramírez).
authors: Alfredo
authors: A
authors: Castañeda-Ramírez
authors: Laboratorio de Microbiología Molecular, Departamento de Microbiología e Inmunología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Av. Universidad 3000, Circuito Exterior s/n, CU, Distrito Federal 04510, México (Castañeda-Ramírez, González-Rodríguez, Hernández-Pineda, Verdugo-Rodríguez); Departamento de Zootecnia, Universidad Autónoma Chapingo, Texcoco, México (Castañeda-Ramírez).
authors: Diana
authors: D
authors: González-Rodríguez
authors: Laboratorio de Microbiología Molecular, Departamento de Microbiología e Inmunología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Av. Universidad 3000, Circuito Exterior s/n, CU, Distrito Federal 04510, México (Castañeda-Ramírez, González-Rodríguez, Hernández-Pineda, Verdugo-Rodríguez); Departamento de Zootecnia, Universidad Autónoma Chapingo, Texcoco, México (Castañeda-Ramírez).
authors: J Aide
authors: JA
authors: Hernández-Pineda
authors: Laboratorio de Microbiología Molecular, Departamento de Microbiología e Inmunología, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Av. Universidad 3000, Circuito Exterior s/n, CU, Distrito Federal 04510, México (Castañeda-Ramírez, González-Rodríguez, Hernández-Pineda, Verdugo-Rodríguez); Departamento de Zootecnia, Universidad Autónoma Chapingo, Texcoco, México (Castañeda-Ramírez).
authors: Antonio
authors: A
authors: Verdugo-Rodríguez
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D017347:Brucella melitensis / Q000276:immunology*; D002460:Cell Line; D055785:Gene Knockdown Techniques; D006801:Humans; D008264:Macrophages / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D010587:Phagocytosis / Q000502:physiology*; D050765:Qa-SNARE Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D050765:Qa-SNARE Proteins