Scleral Micro-RNA Signatures in Adult and Fetal Eyes

• Published in: PloS one Vol. 8; no. 10; p. e78984
• Main Authors: Metlapally, Ravikanth, Gonzalez, Pedro, Hawthorne, Felicia A., Tran-Viet, Khanh-Nhat, Wildsoet, Christine F., Young, Terri L.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 21.10.2013; Public Library of Science (PLoS)
• Subjects: Age; Age Factors; Algorithms; Alzheimer's disease; Alzheimers disease; Cancer; Cataracts; Collagen; Comparative analysis; Congenital diseases; Data processing; Diabetic retinopathy; DNA microarrays; Enlargement; Extracellular matrix; Eye; Eye (anatomy); Female; Fetal Development; Fetus - anatomy & histology; Fetus - metabolism; Fetuses; Fibroblasts; Gene expression; Gene Expression Profiling; Gene Expression Regulation; Gene sequencing; Genes; Genomes; Genomics; Growth factors; Humans; Male; MicroRNAs; MicroRNAs - metabolism; Middle Aged; Myopia; Oligonucleotide Array Sequence Analysis; Ribonucleic acid; RNA; Sampling methods; Sclera - embryology; Sclera - growth & development; Sclera - metabolism; Signaling; Tissues; North Carolina; United States > US; California
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0078984

In human eyes, ocular enlargement/growth reflects active extracellular matrix remodeling of the outer scleral shell. Micro-RNAs are small non-coding RNAs that regulate gene expression by base pairing with target sequences. They serve as nodes of signaling networks. We hypothesized that the sclera, like most tissues, expresses micro-RNAs, some of which modulate genes regulating ocular growth. In this study, the scleral micro-RNA expression profile of rapidly growing human fetal eyes was compared with that of stable adult donor eyes using high-throughput microarray and quantitative PCR analyses. Scleral samples from normal human fetal (24 wk) and normal adult donor eyes were obtained (n=4 to 6, each group), and RNA extracted. Genome-wide micro-RNA profiling was performed using the Agilent micro-RNA microarray platform. Micro-RNA target predictions were obtained using Microcosm, TargetScan and PicTar algorithms. TaqMan® micro-RNA assays targeting micro-RNAs showing either highest significance, detection, or fold differences, and collagen specificity, were applied to scleral samples from posterior and peripheral ocular regions (n=7, each group). Microarray data were analyzed using R, and quantitative PCR data with 2^-deltaCt methods. Human sclera was found to express micro-RNAs, and comparison of microarray results for adult and fetal samples revealed many to be differentially expressed (p<0.01, min p= 6.5x10(11)). Specifically, fetal sclera showed increased expression of mir-214, let-7c, let-7e, mir-103, mir-107, and mir-98 (1.5 to 4 fold changes, p<0.01). However, no significant regionally specific differences .i.e., posterior vs. peripheral sclera, were observed for either adult or fetal samples. For the first time, micro-RNA expression has been catalogued in human sclera. Some micro-RNAs show age-related differential regulation, higher in the sclera of rapidly growing fetal eyes, consistent with a role in ocular growth regulation. Thus micro-RNAs represent potential targets for ocular growth manipulation, related to myopia and/or other disorders such as scleral ectasia.