Deletion of the FHL2 gene attenuating neovascularization after corneal injury.
OBJECTIVE
The four-and-one-half LIM domain-containing protein2 (FHL2) is a member of the four-and-a-half LIM domain-only (FHL) gene family. Although FHL2 is expressed in the cornea, its role in angiogenesis is unclear. The aim of this study was to investigate the role of the FHL2 gene in corneal angiogenesis after chemical injury.


METHODS
FHL2-LacZ knock-in mice were used to trace FHL2 gene expression before and after corneal injury. Corneal angiogenesis between FHL2-null mice and wild-type mice that underwent chemical and mechanical denudation of corneal and limbal epithelium were compared. New growth vessel density was assessed by CD31 staining and was analyzed using image analysis software. Levels of vascular endothelial growth factor (VEGF) and cyclooxygenase (COX)-2 proteins were determined by Western blot assay.


RESULTS
beta-Galactosidase staining of corneal tissue in FHL2-LacZ knock-in mice revealed that FHL2 gene expression is upregulated in the corneal epithelium after corneal injury. Ten days after injury, corneal neovascularization was observed in control and FHL2-null mice. New corneal vessel density was found to be lower in the FHL2-null mice injury group than in the wild-type mice injury group. Western blot analysis showed that VEGF and COX-2 protein levels were higher after chemical injury in FHL2-null mice and wild-type mice. However, the upregulated VEGF protein was significantly lower in the FHL2-null mice than in the wild-type mice.


CONCLUSIONS
The decreased chemical-induced corneal angiogenesis found in the FHL2-null mice in this study indicated that FHL2 protein plays a role in inhibiting inflammatory angiogenesis.
Chu
Pao-Hsien
PH
First Cardiovascular Division, Department of Internal Medicine, Chang-Gung Memorial Hospital, Chang-Gung University College of Medicine, Taipei, Taiwan. pchu@adm.cgmh.org.tw
Yeh
Lung-Kun
LK
Lin
Hsin-Chiung
HC
Jung
Shih-Ming
SM
Ma
David Hui-Kang
DH
Wang
I-Jong
IJ
Wu
Hsueh-Hua
HH
Shiu
Tzu-Fang
TF
Chen
Ju
J
D000818:Animals; D015153:Blotting, Western; D002057:Burns, Chemical / Q000209:etiology; D065306:Corneal Injuries; D016510:Corneal Neovascularization / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004195:Disease Models, Animal; D005126:Eye Burns / Q000139:chemically induced* / Q000378:metabolism; D017353:Gene Deletion; D005786:Gene Expression Regulation / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics*; D060850:LIM-Homeodomain Proteins; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009124:Muscle Proteins / Q000235:genetics*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D012972:Sodium Hydroxide; D014157:Transcription Factors / Q000235:genetics*; D015854:Up-Regulation; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
C491382:Fhl2 protein, mouse; D018398:Homeodomain Proteins; D060850:LIM-Homeodomain Proteins; D009124:Muscle Proteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D012972:Sodium Hydroxide; C077623:Ptgs2 protein, mouse; D051546:Cyclooxygenase 2