Proinflammatory cytokines induce RANTES and MCP-1 synthesis in human corneal keratocytes but not in corneal epithelial cells. Beta-chemokine synthesis in corneal cells.
OBJECTIVE
To determine whether human corneal epithelial cells and keratocytes produce chemokines regulated upon activation, normal T-cell expressed and secreted (RANTES) protein and monocyte chemotactic protein-1 (MCP-1) after exposure to proinflammatory cytokines interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor-alpha (TNF-alpha).


METHODS
Pure cultures of human corneal epithelial cells and keratocytes were exposed to increasing concentrations of either human recombinant IL-1 alpha or TNF-alpha. At selected time intervals after exposure, culture supernatants were removed and assayed for RANTES and MCP-1 by the enzyme-linked immunosorbent assay. Total RNA was extracted from the cell cultures, and steady state mRNA levels were measured by reverse transcriptase-polymerase chain reaction.


RESULTS
Exposure to keratocytes to either IL-1 alpha or TNF-alpha resulted in > 100-fold increases in RANTES protein secretion and > 150-fold increases in MCP-1 protein secretion, as well as in rapid sustained increases in intracellular levels of their corresponding mRNAs. Exposure of corneal epithelial cells to IL-1 alpha and TNF-alpha did not stimulate MCP-1 secretion nor intracellular levels of MCP-1 mRNA. Epithelial cells also failed to secrete RANTES protein even through the two inducing cytokines did stimulate increased expression of RANTES mRNA.


CONCLUSIONS
These results suggest that RANTES and MCP-1 gene expression in human keratocytes differs markedly from their expression in human corneal epithelial cells and that the stroma of the cornea may be more important than the epithelium in recruitment of mononuclear leukocytes responsible for cell-mediated immunity.
Tran
M T
MT
Department of Microbiology/Immunology, College of Medicine, University of South Alabama, Mobile 36688, USA.
Tellaetxe-Isusi
M
M
Elner
V
V
Strieter
R M
RM
Lausch
R N
RN
Oakes
J E
JE
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000235:genetics; D018946:Chemokine CCL5 / Q000096:biosynthesis* / Q000235:genetics; D018925:Chemokines / Q000096:biosynthesis; D003315:Cornea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016207:Cytokines / Q000494:pharmacology; D017931:DNA Primers / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012313:RNA / Q000302:isolation & purification; D012333:RNA, Messenger / Q000032:analysis; D011994:Recombinant Proteins / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D018932:Chemokine CCL2; D018946:Chemokine CCL5; D018925:Chemokines; D016207:Cytokines; D017931:DNA Primers; D007375:Interleukin-1; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D012313:RNA