Alfonso Santiago-Téllez1,2, Laura Estela Castrillón-Rivera2, Alejandro Palma-Ramos2, Juan Manuel Bello-López3, Teresita Sainz-Espuñes2, Adriana Contreras-Paredes4, Julieta Luna-Herrera5, Jorge Ismael Castañeda-Sánchez2. 1. Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, Calzada del Hueso 1100, Villa Quietud, Coyoacán, Mexico city, Mexico. 2. Departamento de Sistemas Biológicos, Universidad Autónoma Metropolitana Unidad Xochimilco, Calzada del Hueso 1100, Villa Quietud, Coyoacán, Mexico city, Mexico. 3. Unidad de Investigación en Microbiología y Toxicología, Hospital Juárez de México, Av. Instituto Politécnico Nacional 5160, Magdalena de las Salinas, Gustavo A. Madero, Mexico city, Mexico. 4. Subdirección de Investigación Básica, Instituto Nacional de Cancerología, Avenida San Fernando 22, Sección XVI, Tlalpan, Mexico city, Mexico. 5. Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación Manuel Carpio y Plan de Ayala S/N, Santo Tomás, Miguel Hidalgo, Mexico city, Mexico.
Abstract
BACKGROUND: Actinomycetoma is a syndrome of the skin characterized by chronic inflammation and lesions with nodular grain-like structures. The most common aetiological agents are Nocardia brasiliensis and Actinomadura madurae. In response to infection with these organisms the body produces an inflammatory immune response in the skin. The aim of the present study was to determine the production of chemokines, pro-inflammatory cytokines, antimicrobial peptides and the expression of Toll-like receptors (TLRs) in keratinocytes infected by A. madurae. METHODS: A cell line of HaCaT keratinocytes was infected with A. madurae at a multiplicity of infection of 20:1 for 2 h and the samples were collected from 2 to 72 h post-infection. Intracellular replication of the bacterium was evaluated by counting of colony-forming units, the TLR expression and antimicrobial peptide production were assayed by confocal microscopy and chemokine and pro-inflammatory cytokine levels were determined by enzyme-linked immunosorbent assay. RESULTS: Early in the infection, A. madurae was able to achieve intracellular replication in keratinocytes, however, the cells eventually controlled the infection. In response to the infection, keratinocytes overexpressed TLR2 and TLR6, produced high concentrations of cytokines monocyte chemoattractant protein-1, interleukin 8, human β-defensin-1, human β-defensin-2 and LL37 and low levels of tumour necrosis factor α. CONCLUSIONS: The human keratinocytes contribute to the inflammatory process in response to A. madurae infection by overexpressing TLRs and producing chemokines, pro-inflammatory cytokines and antimicrobial peptides.
BACKGROUND:Actinomycetoma is a syndrome of the skin characterized by chronic inflammation and lesions with nodular grain-like structures. The most common aetiological agents are Nocardia brasiliensis and Actinomadura madurae. In response to infection with these organisms the body produces an inflammatory immune response in the skin. The aim of the present study was to determine the production of chemokines, pro-inflammatory cytokines, antimicrobial peptides and the expression of Toll-like receptors (TLRs) in keratinocytes infected by A. madurae. METHODS: A cell line of HaCaT keratinocytes was infected with A. madurae at a multiplicity of infection of 20:1 for 2 h and the samples were collected from 2 to 72 h post-infection. Intracellular replication of the bacterium was evaluated by counting of colony-forming units, the TLR expression and antimicrobial peptide production were assayed by confocal microscopy and chemokine and pro-inflammatory cytokine levels were determined by enzyme-linked immunosorbent assay. RESULTS: Early in the infection, A. madurae was able to achieve intracellular replication in keratinocytes, however, the cells eventually controlled the infection. In response to the infection, keratinocytes overexpressed TLR2 and TLR6, produced high concentrations of cytokines monocyte chemoattractant protein-1, interleukin 8, human β-defensin-1, human β-defensin-2 and LL37 and low levels of tumour necrosis factor α. CONCLUSIONS: The human keratinocytes contribute to the inflammatory process in response to A. madurae infection by overexpressing TLRs and producing chemokines, pro-inflammatory cytokines and antimicrobial peptides.