Modulation of migration and Ca2+ signaling in retinal pigment epithelium cells by recombinant human CTGF.
OBJECTIVE
The migration of retinal pigment epithelium (RPE) cells is an initial step in the development of proliferative vitreoretinopathy (PVR). We investigated the expression of connective tissue growth factor (CTGF) in an in vitro model of wound healing and effects of recombinant human CTGF (rhCTGF) on modulating migration and Ca(2+) signaling in RPE cells.


METHODS
Cultured human RPE monolayers were used to establish a wound-healing model. Western blot and in situ hybridization were used to detect the CTGF expression in RPE cells. Migration of RPE cells was measured under the stimulation of rhCTGF alone or in combination with dexamethasone (DEX) or 8-Br-cAMP. To determine the concentration of cytoplasmic-free Ca(2+) ([Ca(2+)]i) responding to CTGF, the fluo-3/AM-loaded RPE cells were observed with a laser scanning confocal microscope.


RESULTS
The CTGF expression first increased after being wounded in RPE cells, then reached a peak and maintained at a high level. The positive expression was mainly at the edge of scrape and in motile RPE cells. rhCTGF-stimulated RPE cells migrated in a dose-dependent manner, and both DEX and 8-Br-cAMP could significantly inhibit the CTGF-induced migrations. CTGF induced a (Ca(2+))i elevation in RPE cells in a concentration-dependent manner. Moreover, stimulation of RPE cells with CTGF and DEX or 8-Br-cAMP counteracted the elevation of (Ca(2+))i induced by CTGF.


CONCLUSIONS
The CTGF expression could be induced by an in vitro model of scrape wounding. rhCTGF stimulated the migration and Ca(2+) signal pathway in RPE cells in a dose-dependent manner, and DEX and 8-Br-cAMP suppressed this effect. Our results indicate that CTGF is involved in the wound-healing process and plays an important role in the pathogenesis of intraocular proliferative diseases.
Guo
Chang-Mei
CM
Department of Ophthalmology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
Wang
Yu-Sheng
YS
Hu
Dan
D
Han
Quan-Hong
QH
Wang
Jing-Bo
JB
Hou
Xu
X
Hui
Yan-Nian
YN
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000328:Adult; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects*; D018929:Cell Culture Techniques; D002465:Cell Movement / Q000187:drug effects*; D055513:Connective Tissue Growth Factor / Q000008:administration & dosage* / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation; D006801:Humans; D011994:Recombinant Proteins / Q000008:administration & dosage*; D055213:Retinal Pigment Epithelium / Q000187:drug effects* / Q000378:metabolism; D018630:Vitreoretinopathy, Proliferative / Q000378:metabolism; D014945:Wound Healing / Q000187:drug effects
D000893:Anti-Inflammatory Agents; C526317:CCN2 protein, human; D011994:Recombinant Proteins; D055513:Connective Tissue Growth Factor; D015124:8-Bromo Cyclic Adenosine Monophosphate; D003907:Dexamethasone