Downregulation of IRS-1 expression causes inhibition of corneal angiogenesis.
OBJECTIVE
The antiangiogenic effect of an antisense oligodeoxynucleotide (ODN) targeting insulin receptor substrate (IRS)-1 was evaluated on rat corneal neovascularization.


METHODS
Eyes with neovessels were treated with subconjunctival injections of IRS-1 antisense oligonucleotide (ASODN), IRS-1 sense ODN (SODN), or PBS. At 8 and 24 hours after the first subconjunctival injection, the expression of IRS-1, VEGF, and IL-1beta mRNA was evaluated. IRS-1 protein levels were also measured at 8 hours by Western blot analysis (n = 4/group). On day 10, corneal neovascularization was quantified in flatmount corneas of rats treated daily from days 4 to 9.


RESULTS
On day 10, new vessels covered 95.5% +/- 4% of the corneal area in PBS-treated eyes, 92% +/- 7% in SODN-treated eyes and 59% +/- 20% in ASODN-treated eyes (P < 0.001). In the ASODN-treated group, the expression and synthesis of IRS-1 were significantly downregulated when compared with the control groups. ASODN did not significantly affect the expression of VEGF but significantly decreased the expression of IL-1beta at 24 hours (P = 0.04).


CONCLUSIONS
Subconjunctival injections of IRS-1 antisense ODN significantly inhibit rat corneal neovascularization. This effect may be mediated by a downregulation of IL-1beta. IRS-1 proteins may be interesting targets for the regulation of angiogenesis mediated by insulin, hypoxia, or inflammation.
Berdugo
Marianne
M
Institut National de la Santé et de la Recherche Médicale (INSERM), U598, Paris, France.
Andrieu-Soler
Charlotte
C
Doat
Marc
M
Courtois
Yves
Y
BenEzra
David
D
Behar-Cohen
Francine
F
D020533:Angiogenesis Inhibitors / Q000627:therapeutic use*; D000818:Animals; D015153:Blotting, Western; D003228:Conjunctiva / Q000187:drug effects; D016510:Corneal Neovascularization / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D004195:Disease Models, Animal; D015536:Down-Regulation; D007150:Immunohistochemistry; D007267:Injections; D055504:Insulin Receptor Substrate Proteins; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism; D020319:Oligodeoxyribonucleotides, Antisense / Q000627:therapeutic use*; D010750:Phosphoproteins / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D013047:Specific Pathogen-Free Organisms; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism
D020533:Angiogenesis Inhibitors; D055504:Insulin Receptor Substrate Proteins; D007375:Interleukin-1; C526296:Irs1 protein, rat; D020319:Oligodeoxyribonucleotides, Antisense; D010750:Phosphoproteins; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat