All-trans retinoic Acid regulates cx43 expression, gap junction communication and differentiation in primary lens epithelial cells.
OBJECTIVE
To examine the effect of all-trans retinoic acid (ATRA) treatment on connexin 43 (Cx43) expression, gap junction intercellular communication (GJIC), and cellular differentiation in primary canine lens epithelial cells (LEC).


METHODS
Dose and time-dependent effects of ATRA on Cx43 protein, mRNA and GJIC, were assessed by immunoblotting, quantitative reverse transcription polymerase chain reaction (qRT-PCR), and scrape loading/dye transfer assays, respectively. Expression of beta crystallin was evaluated by immunoblotting.


RESULTS
Treatment with ATRA at non-cytotoxic concentrations significantly increased Cx43 protein, mRNA and GJIC in primary canine LEC. Treatment with ATRA for five and seven days increased levels of beta crystallin, a protein marker of LEC differentiation. Inhibition of GJIC via pre-treatment with a synthetic inhibitor, 18-alpha glycyrrethinic acid (AGA), reduced ATRA-induced increases in Cx43 and GJIC and partially blocked ATRA-induced beta crystallin protein.


CONCLUSIONS
Treatment with ATRA significantly increased Cx43 expression and GJIC in canine LEC, and these effects were associated with increased LEC differentiation. Results from this study suggest that functional gap junctions may play a role in the modulation of cellular differentiation in primary canine LEC.
Long
Amy C
AC
The Ohio State University, Interdisciplinary Ph.D Program in Nutrition, Department of Human Nutrition, Department of Ophthalmology, Biomedical Engineering Center, College of Optometry, Department of Veterinary Clinical Sciences, Columbus, Ohio, USA.
Bomser
Joshua A
JA
Grzybowski
Deborah M
DM
Chandler
Heather L
HL
D000818:Animals; D002229:Carbenoxolone / Q000494:pharmacology; D002450:Cell Communication / Q000187:drug effects*; D002454:Cell Differentiation / Q000187:drug effects*; D049109:Cell Proliferation; D002478:Cells, Cultured; D018031:Connexin 43 / Q000235:genetics* / Q000378:metabolism; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D017629:Gap Junctions / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects*; D015151:Immunoblotting; D007908:Lens, Crystalline / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014212:Tretinoin / Q000008:administration & dosage / Q000494:pharmacology*; D038204:beta-Crystallins / Q000378:metabolism
D018031:Connexin 43; D012333:RNA, Messenger; D038204:beta-Crystallins; D014212:Tretinoin; D002229:Carbenoxolone