Lipopolysaccharide activation of pericyte’s Toll-like receptor-4 regulates co-culture permeability

• Published in: The American journal of surgery 2007-06, Vol.193 (6), p.730-735
• Main Authors: Edelman, David A., M.D, Jiang, Yang, M.D, Tyburski, James G., M.D, Wilson, Robert F., M.D, Steffes, Christopher P., M.D
• Format: Article
• Language: English
• Subjects: Acute respiratory distress syndrome; Albumins - metabolism; Animals; Biological and medical sciences; Blotting, Western; Capillary leak; Cell Membrane Permeability - drug effects; Cell Membrane Permeability - genetics; Cells, Cultured; Co-culture; Coculture Techniques; Endothelial Cells - cytology; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Endothelium, Vascular - cytology; Endothelium, Vascular - drug effects; Endothelium, Vascular - metabolism; Gene Silencing - drug effects; General aspects; Lung - blood supply; Lung - cytology; Lungs; Medical sciences; Membranes; Pericytes; Pericytes - cytology; Pericytes - drug effects; Pericytes - metabolism; Permeability; Pneumology; Polysaccharides - pharmacology; Proteins; Rats; Rats, Sprague-Dawley; Respiratory distress syndrome; Respiratory system : syndromes and miscellaneous diseases; RNA, Small Interfering - genetics; Rodents; Sepsis; Smooth muscle; Studies; Surgery; TLR-4; Toll-Like Receptor 4 - drug effects; Toll-Like Receptor 4 - genetics; Toll-Like Receptor 4 - metabolism
• ISSN: 0002-9610; 1879-1883
• DOI: 10.1016/j.amjsurg.2006.08.086

Abstract Background Pericytes (PCs) have a synergistic relationship with endothelial cells (MVEC) in regulating capillary permeability. PCs express Toll-like receptor-4 (TLR-4). We hypothesize one mechanism of MVEC/PC co-culture permeability is regulated through lipopolysaccharide (LPS) activation of pericyte TLR-4. Methods Rat PCs were harvested and cultured. PCs were transfected with siRNA targeted to TLR-4. Western blotting was used to confirm gene silencing of TLR-4. A previously described co-culture permeability assay was performed after LPS treatment. Results Western blot confirmed successful silencing of TLR-4 in PCs, which was sustained for 7 days. A dose- and time-dependent effect of LPS on albumin clearance was seen in MVEC/PC co-cultures. Co-cultures with TLR-4 silenced in PCs eliminated the LPS dose-dependent increase in albumin clearance. Conclusions TLR-4 regulates pericyte mediated capillary leak seen with LPS exposure. Our TLR-4 silencing model can be used to further investigate TLR-4’s role in pericyte mediated capillary leak.