CD14 glycoprotein expressed in vascular smooth muscle cells.
The inducible nitric oxide synthase (iNOS) expression in vascular smooth muscle cells is an important factor for pathogenesis of septic shock or multiple organ dysfunction syndrome. The mechanisms of iNOS expression in such conditions are partly known. This study tried to clarify the signal transduction of lipopolysaccharide (LPS) single stimulation that induces iNOS mRNA and protein in vascular smooth muscle cells (VSMC). VSMC were primarily cultured from rat aorta. The concentrations of nitrite in culture media were measured by the Griess reaction. Western blottings and immunoreaction for iNOS, nuclear factor kappaB (NFkappaB) p65, and CD14 protein were performed. mRNAs of iNOS and tumor necrosis factor (TNF) alpha were analyzed by RT-PCR. Genistein inhibited LPS induced early phase nitrite production, while pyrrolidine dithiocarbamate (PDTC) inhibited nitrite production at a late phase. PDTC significantly reduced NFkappaB p65 and iNOS protein expression by LPS. TNFalpha mRNA expression by LPS was not detected in VSMC. Membranous CD14 glycoprotein was detected in VSMC and soluble CD14 glycoprotein was not detected in fetal bovine serum added in culture media. These results suggest that CD14 glycoprotein is present on the cell membranes of VSMC, a non-myelomonocyte lineage, acting as an LPS receptor. Activations of tyrosine kinase and NFkappaB p65 are essential for iNOS expression by LPS single stimulation, while TNFalpha is not a concern to iNOS expression in VSMC.
Choi
Hyoung Chul
HC
Department of Pharmacology, College of Medicine, Yeungnam University, Namgu, Daegu, Korea. hcchoi@med.yu.ac.kr
Lee
Kwang Youn
KY
D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology; D018950:Lipopolysaccharide Receptors / Q000096:biosynthesis* / Q000235:genetics; D008070:Lipopolysaccharides / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides