All-trans retinoic acid regulates the expression of the extracellular matrix protein fibulin-1 in the guinea pig sclera and human scleral fibroblasts.
OBJECTIVE
Fibulin-1 (FBLN1) mRNA is expressed in human sclera and is an important adhesion modulatory protein that can affect cell-matrix interactions and tissue remodeling. Scleral remodeling is influenced by all-trans retinoic acid (RA). Our purpose was to confirm the presence of fibulin-1 protein in guinea pig sclera and investigate the effect of RA on the expression of fibulin-1 in guinea pig sclera in vivo and in cultured human scleral fibroblasts (HSFs).


METHODS
Confocal fluorescence microscopy was used to study fibulin-1 and aggrecan expression and localization in sclera from control guinea pigs and in animals given RA by daily gavage from 4 to 8 days of age. The effects of RA (from 10(-9) to 10(-5) M) on fibulin-1 expression in HSFs were observed by immunohistochemistry and assayed by real-time PCR and western blot analysis.


RESULTS
Fibulin-1 protein expression was detected by confocal fluorescence microscopy in guinea pig sclera and in cultured HSFs. Upregulation of fibulin-1 in scleral tissue was observed after feeding with RA. In vitro, the level of Fbln1 mRNA was increased after treatment of HSFs with RA (at concentrations of 10(-8) to 10(-6) M; p<0.001), with a maximum effect at 10(-7) M. Fibulin-1 protein levels were significantly increased after treatment of HSFs with 10(-7) M of RA for 24 or 48 h (p<0.05).


CONCLUSIONS
Fibulin-1 protein was expressed in guinea pig sclera and cultured HSFs. Expression was regulated by RA, a molecule known to be involved in the regulation of eye growth. Further studies on the role of fibulin-1 in the regulation of eye growth, including during the development of myopia, are therefore warranted.
Li
Chuanxu
C
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
McFadden
Sally A
SA
Morgan
Ian
I
Cui
Dongmei
D
Hu
Jianmin
J
Wan
Wenjuan
W
Zeng
Junwen
J
D000293:Adolescent; D053674:Aggrecans / Q000378:metabolism; D000818:Animals; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002648:Child; D018920:Coculture Techniques; D016326:Extracellular Matrix Proteins / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006168:Guinea Pigs / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012590:Sclera / Q000166:cytology* / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology*; D055815:Young Adult
D053674:Aggrecans; D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; D012333:RNA, Messenger; C060820:fibulin; D014212:Tretinoin
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