Mycobacterium tuberculosis (Mtb), the etiological agent of tuberculosis (TB) in humans, releases extracellular vesicles in vitro and in vivo. Like extracellular vesicles released by Gram-positive bacteria, mycobacterial extracellular vesicles originate at the plasma membrane. Mycobacterial membrane vesicles contain a broad range of immunologically active proteins and glycolipids that can influence host cellular immunity. When added to cells in culture, isolated membrane vesicles can regulate the immune response of uninfected macrophages, T-cells and dendritic cells suggesting a pathogenic role of membrane vesicles in immunomodulation and immune evasion. It has been recognized that vesicle biogenesis in M. tuberculosis is an active and regulated process, but the molecular mechanisms and factors involved remain largely unknown. Iron limitation, a condition encountered in the host, induces the production of membrane vesicles in M. tuberculosis. These vesicles contain the hydrophobic siderophore mycobactin, which can serve as an iron donor and supports replication of iron-starved mycobacteria. Based on these observations we have used a genetic approach to identify the principles governing iron regulated vesicle biogenesis and the molecular determinants of vesiculation in M. tuberculosis, which will be the focus of the presentation.
G. Marcela Rodriguez is an Associate Professor in the Public Health Research Institute, Department of Medicine at New Jersey Medical School, Rutgers University in Newark, New Jersey. She received her undergraduate degree from Pontificia Universidad Javeriana in Colombia SA, and a Ph.D from New York University, NY. During her training, Dr. Rodriguez developed a keen interest in infections diseases particularly tuberculosis. As a post-doctoral fellow (1999-2007) in Issar Smith’s lab at The Public Health Research Institute she was awarded a fellowship from the Parker Francis Foundation to study iron metabolism and regulation in M. tuberculosis. Dr. Rodriguez received an award from The Hispanic Center of Excellence at UMDNJ in 2011 and start her independent research program, which has been focused in the metallobiology of M. tuberculosis and its role in pathogenesis.