Molecular mechanism of transcytosis of Leptospira interrogans across vascular endothelial cells / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the molecular mechanism of transcytosis of Leptospira interrogans ( L. interrogans) across vascular endothelial cells. Methods:Transwell assay was performed to observe the ability of L. interrogans strain Lai across the monolayer of human vascular endothelial cells (HUVEC). Transmission electron microscopy and laser confocal microscopy were used to detect the endocytic vesicles containing L. interrogans strain Lai in HUVEC. The leptospiral endocytic pathway was determined by endocytic inhibition test. Laser confocal microscopy was also used detect the co-localization of L. interrogans with lysosomal marker LAMP1 in HUVEC. The exocytosis of L. interrogans from HUVEC was detected using Petroff-Hausser counting chamber and darkfield microscopy. Results:L. interrogans strain Lai could rapidly transmigrate through HUVEC monolayers and be internalized into HUVEC by PI3K-microfilament-dependent endocytosis to form leptospiral endocytic vesicles. The internalized L. interrogans did not co-localize with LAMP1, indicating the leptospiral endocytic vesicles did not fuse with lysosomes. The exocytosis of internalized L. interrogans was through FAK-microfilament/microtubule pathway. Conclusions:L. interrogans strain Lai could transmigrate through HUVEC by transcytosis to diffuse in vivo and cause disease aggravation.