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The Chlamydial Inclusion Preferentially Intercepts Basolaterally Directed Sphingomyelin‐Containing Exocytic Vacuoles
Author(s) -
Moore Elizabeth R.,
Fischer Elizabeth R.,
Mead David J.,
Hackstadt Ted
Publication year - 2008
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2008.00828.x
Subject(s) - biology , vacuole , microbiology and biotechnology , sphingomyelin , vesicle , endosome , chlamydiae , ceramide , brefeldin a , inclusion bodies , golgi apparatus , chlamydia trachomatis , biochemistry , cytoplasm , cholesterol , virology , intracellular , endoplasmic reticulum , membrane , apoptosis , escherichia coli , gene
Chlamydiae replicate intracellularly within a unique vacuole termed the inclusion. The inclusion circumvents classical endosomal/lysosomal pathways but actively intercepts a subset of Golgi‐derived exocytic vesicles containing sphingomyelin (SM) and cholesterol. To further examine this interaction, we developed a polarized epithelial cell model to study vectoral trafficking of lipids and proteins to the inclusion. We examined seven epithelial cell lines for their ability to form single monolayers of polarized cells and support chlamydial development. Of these cell lines, polarized colonic mucosal C2BBe1 cells were readily infected with Chlamydia trachomatis and remained polarized throughout infection. Trafficking of (6‐(( N ‐(7‐nitrobenz‐2‐oxa‐1, 3‐diazol‐4‐yl) amino)hexanoyl)sphingosine) (NBD‐C 6 ‐ceramide) and its metabolic derivatives, NBD‐glucosylceramide (GlcCer) and NBD‐SM, was analyzed. SM was retained within L2‐infected cells relative to mock‐infected cells, correlating with a disruption of basolateral SM trafficking. There was no net retention of GlcCer within L2‐infected cells and purification of C. trachomatis elementary bodies from polarized C2BBe1 cells confirmed that bacteria retained only SM. The chlamydial inclusion thus appears to preferentially intercept basolaterally‐directed SM‐containing exocytic vesicles, suggesting a divergence in SM and GlcCer trafficking. The observed changes in lipid trafficking were a chlamydia‐specific effect because Coxiella burnetii ‐infected cells revealed no changes in GlcCer or SM polarized trafficking.