Mycobacteria entry and trafficking into endothelial cells.

Endothelial cells are susceptible to infection by mycobacteria, but the endocytic mechanisms that mycobacteria exploit to enter host cells and their mechanisms of intracellular transport are completely unknown. Using pharmacological inhibitors, we determined that the internalization of Mycobacterium tuberculosis (MTB), Mycobacterium smegmatis (MSM), and Mycobacterium abscessus (MAB) is dependent on the cytoskeleton and is differentially inhibited by cytochalasin D, nocodazole, cycloheximide, wortmannin, and amiloride. Using confocal microscopy, we investigated their endosomal trafficking by analyzing Rab5, Rab7, LAMP-1, and cathepsin D.