Increased expression of heme oxygenase-1 in human retinal pigment epithelial cells by transforming growth factor-beta.
Antibodies specific for heme oxygenase-1 (HO-1) were produced in rabbits, using the multiple antigen peptide (MAP) technique, and were employed to investigate the ability of transforming growth factor-beta 1 (TGF-beta 1) to induce the HO-1 protein in cultured human retinal pigment epithelial (RPE) cells. Western blot analyses showed that the cytokine induced HO-1 in these cells in a time- and dose-dependent manner. TGF-beta 1 also increased the mRNA for HO-1 in treated cells prior to the increase in HO-1 protein. The induction was effectively blocked by a neutralizing antibody preparation against TGF-beta 1. When tested under similar conditions, other growth factors such as basic fibroblast growth factor-I, platelet-derived growth factor, insulin-like growth factor, transforming growth factor-alpha, and epidermal growth factor did not show appreciable induction of HO-1. Lipopolysaccharide, tumor necrosis factor-alpha, and interferon-gamma were also not inducers, although TGF-beta 2 effectively induced HO-1. Heavy metal ions and thiol reagents were also highly potent inducers of HO-1 in human RPE cells. The induction of HO-1 by TGF-beta 1 was also observed in bovine choroid fibroblasts, but not in HELA, HEL or bovine corneal fibroblasts. Our results demonstrate for the first time that HO-1 can be induced by an important cytokine, TGF-beta 1, causing an increase in the expression of both HO-1 message and protein in specific neuroepithelial and fibroblast cells.
Kutty
R K
RK
Laboratory of Retinal Cell, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892.
Nagineni
C N
CN
Kutty
G
G
Hooks
J J
JJ
Chader
G J
GJ
Wiggert
B
B
D000595:Amino Acid Sequence; D002478:Cells, Cultured; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007120:Immunochemistry; D008969:Molecular Sequence Data; D009994:Osmolar Concentration; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D016212:Transforming Growth Factor beta; D006419:Heme Oxygenase (Decyclizing)