Research Article: Mycobacterium bovis-BCG regulates macrophage vasodilator-stimulated phosphoprotein

Vasodilator-stimulated phosphoprotein (VASP) is a processive actin polymerase that regulates membrane architecture, cell motility, and pathophysiologic processes such as metastatic invasion. VASP is also a putative regulator of host-pathogen interactions. Intracellular pathogens such as Listeria monocytogenes, Cryptosporidium parvum, and Mycobacterium marnium are known to utilize the host's actin network to facilitate entry into and motility within host cells. In order to determine if VASP is involved in mediating cytoskeletal rearrangement in cells infected with Mycobacterium bovis-BCG, a model organism for the study of Mycobacterium tuberculosis, murine macrophages were infected with the bacterium and analyzed by immunofluorescence. Antibodies against VASP were used to determine its localization. Results indicate that VASP is present on the membrane of murine macrophages in an evenly distributed fashion. Macrophages infected with M. bovis-BCG showed punctate VASP structures. Activated macrophages infected with M. bovis-BCG showed punctate VASP structures in addition to phagosomes. VASP was also located to what is believed to be the phagosomal cup. These results indicate that VASP localization is mediated by M. bovis-BCG infection. M. bovis-BCG may alter the actin cytoskeleton to evade the antimicrobial response in order to persist in the host.