Connexin43 knockdown accelerates wound healing but inhibits mesenchymal transition after corneal endothelial injury in vivo.
OBJECTIVE
To explore connexin43 (Cx43) knockdown as an efficient treatment for corneal endothelial injury in an in vivo rat corneal scrape injury model.


METHODS
Scrape injury was induced in the corneal endothelium, and immunolabeling (ZO-1, alpha-SMA, Cx43) was performed to analyze changes in Cx43 expression during wound healing. Single injection of Cx43 antisense oligodeoxynucleotide (AS-ODN), small interfering RNA (siRNA), or adenovirus (CMV-Cx43-mRFP1) was applied into the anterior chamber simultaneously with the injury, and wound closure was examined by immunolabeling (ZO-1, Cx43) and propidium iodide staining. Corneal endothelium proliferation on day 1 after injury was studied by Ki67-immunolabeling. Cx43-knockdown treatment was performed also without injury, and its effect on Cx43 expression and Ki67 immunolabeling was examined. The postinjury appearance of myofibroblasts in Cx43 AS-ODN- and sense-ODN-treated corneas was compared by alpha-SMA-immunolabeling.


RESULTS
Complete wound closures were observed in five of six corneas on day 3 after injury with either Cx43 AS-ODN or siRNA treatment, whereas no complete closure was observed on day 3 in the control corneas (S-ODN, zero of six; or nonsense siRNA, zero of six). Consistently, Cx43 overexpression using adenovirus delayed wound closure. Cx43 knockdown increased the number of Ki67-positive proliferating cells on day 1, whereas it decreased the number of alpha-SMA-positive myofibroblasts on day 5. Cx43 knockdown without injury decreased Cx43 expression and induced endothelial proliferation in vivo.


CONCLUSIONS
These results show that Cx43 knockdown induces corneal endothelium proliferation but inhibits endothelial-mesenchymal transition/transformation after injury, suggesting that Cx43 knockdown is a new therapeutic approach for acceleration of wound closure and for prevention of retrocorneal fibrous membrane formation.
Nakano
Yukiko
Y
Departments of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Kawaramachi Hirokoji, Kamigyo-ku, Kyoto, Japan.
Oyamada
Masahito
M
Dai
Ping
P
Nakagami
Takuo
T
Kinoshita
Shigeru
S
Takamatsu
Tetsuro
T
D000199:Actins / Q000378:metabolism; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism; D049109:Cell Proliferation; D018031:Connexin 43 / Q000235:genetics* / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004195:Disease Models, Animal; D004728:Endothelium, Corneal / Q000293:injuries* / Q000378:metabolism / Q000473:pathology; D015807:Eye Injuries, Penetrating / Q000378:metabolism* / Q000473:pathology; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D020868:Gene Silencing / Q000502:physiology*; D005822:Genetic Vectors; D007124:Immunoenzyme Techniques; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism / Q000473:pathology; D018613:Microscopy, Confocal; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D053781:Transforming Growth Factor beta2 / Q000378:metabolism; D014945:Wound Healing / Q000502:physiology*; D062826:Zonula Occludens-1 Protein
D000199:Actins; D018031:Connexin 43; D019394:Ki-67 Antigen; D008565:Membrane Proteins; D016376:Oligonucleotides, Antisense; D010750:Phosphoproteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C569044:Tjp1 protein, rat; D053781:Transforming Growth Factor beta2; D062826:Zonula Occludens-1 Protein; D016222:Fibroblast Growth Factor 2; D000242:Cyclic AMP