Mitogenic and antiapoptotic effects of various growth factors on human corneal fibroblasts.
OBJECTIVE
To investigate both the effects of various growth factors on the proliferation of human corneal fibroblasts and the abilities of these factors to protect the cells from apoptosis.


METHODS
Cultured human corneal fibroblasts were incubated separately with 11 different growth factors whose receptors are expressed by these cells. Cell proliferation was evaluated by measurement of [(3)H]thymidine incorporation. The activation of the protein kinase Akt, which plays an important role in antiapoptotic signaling, was assessed by immunoblot analysis with antibodies specific for a phosphorylated form of the enzyme. Apoptosis was quantitated by the TdT-mediated dUTP-biotin nick-end labeling (TUNEL) assay.


RESULTS
Of the 11 growth factors examined, platelet-derived growth factor, insulin, insulin-like growth factors-1 and -2, and epidermal growth factor, each stimulated the proliferation of corneal fibroblasts, induced the activation of Akt in these cells, and protected them from apoptosis induced by sodium nitroprusside (SNP). Basic fibroblast growth factor, keratinocyte growth factor, nerve growth factor, and hepatocyte growth factor stimulated cell proliferation but did not induce Akt activation or protect the cells from SNP-induced apoptosis. Transforming growth factor-beta1 and -beta2 did not stimulate proliferation and had no effect on Akt activity or on SNP-induced apoptosis.


CONCLUSIONS
In terms of their modulatory effects on the proliferation and apoptosis of human corneal fibroblasts, the 11 growth factors examined can be classified into three groups. These growth factors may both contribute to maintenance of the cornea and coordinate the proliferative and apoptotic responses of corneal fibroblasts during corneal wound healing.
Yanai
Ryoji
R
Department of Biomolecular Recognition and Ophthalmology, Yamaguchi University School of Medicine, 1-1-1 Minami-Kogushi, Ube City, Yamaguchi 755-8505, Japan.
Yamada
Naoyuki
N
Kugimiya
Naruji
N
Inui
Makoto
M
Nishida
Teruo
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D003315:Cornea / Q000166:cytology*; D004247:DNA / Q000096:biosynthesis; D005260:Female; D005347:Fibroblasts / Q000187:drug effects* / Q000378:metabolism; D006133:Growth Substances / Q000494:pharmacology*; D006801:Humans; D015151:Immunoblotting; D020287:In Situ Nick-End Labeling; D008297:Male; D008875:Middle Aged; D009599:Nitroprusside / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D011817:Rabbits
D006133:Growth Substances; D011518:Proto-Oncogene Proteins; D009599:Nitroprusside; D004247:DNA; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt