Identification of myopia-related marker proteins in tilapia retinal, RPE, and choroidal tissue following induced form deprivation.
OBJECTIVE
Experimentally induced myopia is characterized by axial elongation of the eye. The molecular pathways leading to this condition are largely unknown, even though many candidate proteins have been proposed to be involved in this process. This study has identified proteins that were differentially expressed in myopic and control combined retina, retinal pigment epithelium (RPE), and choroidal tissue in tilapia (Oreochromis niloticus).


METHODS
Form deprivation was used to induce myopia in tilapia (n = 3). In this initial study on tilapia retina, RPE and choroid, 2-D differential in gel electrophoresis (DIGE) and mass spectrometry were used to identify differentially expressed proteins. Homology-based gene cloning was used to obtain full sequence data for one of the identified proteins.


RESULTS
A total of 18 protein spots separated by 2-D electrophoresis exhibited statistically significant differences in expression between the myopic and contralateral control combined retinal, RPE, and choroidal tissue. Three proteins were identified at a significance level of p < 0.05, as annexin A5 (down-regulated 47%), Gelsolin (down-regulated 27%), and TCP-1 (CCT) (down-regulated 54%). DNA sequencing of tilapia annexin A5 shows an amino acid sequence identity of 84.5% with the homologous Japanese ricefish annexin max2.


CONCLUSIONS
A proteomics approach has been used to identify differentially expressed proteins in form-deprived combined retinal, RPE, and choroidal tissue from myopic versus normal eyes. The identified proteins may be components of pathways involved in myopia pathogenesis.
Jostrup
Rasmus
R
Department of Biology, University of Waterloo, Waterloo, Ontario, Canada.
Shen
Wei
W
Burrows
Jeffrey T A
JT
Sivak
Jacob G
JG
McConkey
Brendan J
BJ
Singer
Thomas D
TD
D000595:Amino Acid Sequence; D000818:Animals; D017304:Annexin A5 / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D015415:Biomarkers / Q000378:metabolism*; D056404:Chaperonin Containing TCP-1 / Q000378:metabolism; D002829:Choroid / Q000378:metabolism*; D023681:Cichlids; D003001:Cloning, Molecular; D004195:Disease Models, Animal; D015536:Down-Regulation; D015180:Electrophoresis, Gel, Two-Dimensional; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism*; D029941:Fish Proteins / Q000235:genetics / Q000378:metabolism*; D005556:Form Perception; D018260:Gelsolin / Q000378:metabolism; D008969:Molecular Sequence Data; D009216:Myopia / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics; D012160:Retina / Q000378:metabolism*; D055213:Retinal Pigment Epithelium / Q000378:metabolism*; D012683:Sensory Deprivation; D017386:Sequence Homology, Amino Acid; D053719:Tandem Mass Spectrometry
D017304:Annexin A5; D015415:Biomarkers; D005136:Eye Proteins; D029941:Fish Proteins; D018260:Gelsolin; D056404:Chaperonin Containing TCP-1