Form-deprivation myopia in chick induces limited changes in retinal gene expression.
OBJECTIVE
Evidence has implicated the retina as a principal controller of refractive development. In the present study, the retinal transcriptome was analyzed to identify alterations in gene expression and potential signaling pathways involved in form-deprivation myopia of the chick.


METHODS
One-week-old white Leghorn chicks wore a unilateral image-degrading goggle for 6 hours or 3 days (n = 6 at each time). Total RNA from the retina/(retinal pigment epithelium) was used for expression profiling with chicken gene microarrays (Chicken GeneChips; Affymetrix, Santa Clara, CA). To identify gene expression level differences between goggled and contralateral nongoggled eyes, normalized microarray signal intensities were analyzed by the significance analysis of microarrays (SAM) approach. Differentially expressed genes were validated by real-time quantitative reverse transcription-polymerase chain reaction (qPCR) in independent biological replicates.


RESULTS
Small changes were detected in differentially expressed genes in form-deprived eyes. In chickens that had 6 hours of goggle wear, downregulation of bone morphogenetic protein 2 and connective tissue growth factor was validated. In those with 3 days of goggle wear, downregulation of bone morphogenetic protein 2, vasoactive intestinal peptide, preopro-urotensin II-related peptide and mitogen-activated protein kinase phosphatase 2 was validated, and upregulation of endothelin receptor type B and interleukin-18 was validated.


CONCLUSIONS
Form-deprivation myopia, in its early stages, is associated with only minimal changes in retinal gene expression at the level of the transcriptome. While the list of validated genes is short, each merits further study for potential involvement in the signaling cascade mediating myopia development.
McGlinn
Alice M
AM
Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-6075, USA.
Baldwin
Donald A
DA
Tobias
John W
JW
Budak
Murat T
MT
Khurana
Tejvir S
TS
Stone
Richard A
RA
D000367:Age Factors; D000818:Animals; D002645:Chickens; D005135:Eye Protective Devices; D005556:Form Perception / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D023281:Genomics; D009216:Myopia / Q000235:genetics* / Q000503:physiopathology; D020411:Oligonucleotide Array Sequence Analysis; D010469:Perceptual Distortion / Q000502:physiology*; D012160:Retina / Q000254:growth & development / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology