Disruption of CFTR-Dependent Lipid Rafts Reduces Bacterial Levels and Corneal Disease in a Murine Model ofPseudomonas aeruginosaKeratitis

Abstract

P. aeruginosa enters human corneal epithelial cells via lipid rafts containing CFTR, and disruption of raft-mediated uptake of this organism by CD protects against disease and reduces bacterial levels in the mouse model of keratitis.

Homotrimeric Macrophage Migration Inhibitory Factor (MIF) Drives Inflammatory Responses in the Corneal Epithelium by Promoting Caveolin-rich Platform Assembly in Response to Infection

“…P. aeruginosa uses caveolin-1-enriched endocytic pathways to gain entry into lung and corneal epithelial cells (37,42). Caveolin-1 is found in the lipid raft microdomains when isolated into Triton X-100 insoluble fractions (43,44).…”

Cholesterol Modulates CFTR Confinement in the Plasma Membrane of Primary Epithelial Cells

“…Exposure to pathogens leads to ceramide synthesis and the formation of large platforms that are essential for their entry into airway epithelial cells (14,16,34,35,37). We studied the effects of acute adenoviral infection on the transformation of nanoscale lipid rafts into large platforms and on the distribution and dynamics of CFTR using kICS.…”

“…CFTR is central to innate immunity in the airways through its roles in mucociliary clearance, bicarbonate-dependent bacterial killing, and perhaps direct binding and internalization of bacteria (14)(15)(16)37,43). Exposing airway epithelial Biophysical Journal 109(1) 85-94 cells to Pseudomonas aeruginosa causes lipid rafts to fuse into large ceramide-rich platforms, which leads to internalization of the bacterium, apoptosis and cytokine release (34).…”

“…This partitioning may be due to lipid interactions with CFTR itself or with the scaffold protein NHERF1, which links the CFTR to the actin cytoskeleton (12) and also binds to cholesterol at the plasma membrane (13). Colocalization of fluorescently labeled CFTR with the lipid raft markers cholera toxin B or caveolin-1 has also been observed during infection by Pseudomonas aeruginosa (14)(15)(16), and the CFTR has been proposed to bind and internalize bacteria to help clear them from the lumen and to initiate lipid-raft-dependent epithelial cytokine and chemokine release (8,(14)(15)(16)(17). The presence of a CFTR population in the DRM fraction implies heterogeneity among CFTR molecules.…”

Pseudomonas aeruginosa: can studies in engineered cells tell us why is it such a problem in people with cystic fibrosis? Focus on “Cystic fibrosis transmembrane conductance regulator and caveolin-1 regulate epithelial cell internalization of Pseudomonas aeruginosa”

“…This defect is not uniformly manifest in all epithelial tissues. For example, in the cornea, disruption of internalization of PA by perturbing membrane cholesterol reduces bacterial levels and is protective against PA keratitis (18). Others (16) hypothesize that PA internalized through lipid raft-mediated endocytosis is protected from degradation and can survive to cause pneumonia.…”