Lipopolysaccharide-induced expression of intercellular adhesion molecule-1 and chemokines in cultured human corneal fibroblasts.
OBJECTIVE
Invasion of bacteria into the corneal stroma induces the infiltration of leukocytes and subsequent corneal ulceration. The role of corneal fibroblasts in the detection of bacterial invasion into the stroma was investigated by examining the in vitro expression of the receptor complex for lipopolysaccharide (LPS), a common component of Gram-negative bacteria, as well as the possible effects of LPS on both the expression of adhesion molecules and the release of chemokines in cultured human corneal fibroblasts.


METHODS
Expression of the LPS receptor complex, intercellular adhesion molecule (ICAM)-1, and the chemokines interleukin (IL)-8 and monocyte chemotactic protein (MCP)-1 was examined by reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, or immunofluorescence analysis.


RESULTS
Corneal fibroblasts were found to contain transcripts encoding toll-like receptor-4, CD14, and MD-2, all of which are components of the LPS receptor complex. The expression of ICAM-1 at the surface of corneal fibroblasts and the amount of ICAM-1 mRNA in the cells were both increased by LPS. Similarly, LPS increased both the release of IL-8 and MCP-1 by corneal fibroblasts as well as the amounts of the corresponding mRNAs in these cells. These various effects of LPS were potentiated by the presence of a low concentration of human serum.


CONCLUSIONS
Corneal fibroblasts may play an important role in the defense system of the cornea by recognizing the presence of LPS and subsequently expressing adhesion molecules and chemokines that promote leukocyte infiltration.
Kumagai
Naoki
N
Department of Biomolecular Recognition and Ophthalmology, Yamaguchi University School of Medicine, Ube City, Yamaguchi, Japan. kgnaoki@yamaguchi-u.ac.jp
Fukuda
Ken
K
Fujitsu
Youichiro
Y
Lu
Ying
Y
Chikamoto
Nobuhiko
N
Nishida
Teruo
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000954:Antigens, Surface / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics* / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D003315:Cornea / Q000187:drug effects* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000235:genetics* / Q000378:metabolism; D016209:Interleukin-8 / Q000235:genetics* / Q000378:metabolism; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D051218:Lymphocyte Antigen 96; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors
D000954:Antigens, Surface; C111835:CCL2 protein, human; D002352:Carrier Proteins; D018932:Chemokine CCL2; D016209:Interleukin-8; C495377:LY96 protein, human; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D051218:Lymphocyte Antigen 96; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D018799:Intercellular Adhesion Molecule-1