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Yumeng Wang, Tsz Kin Ng, Hoi Kin Wong, Kwong Wai Choy, Chi Pui Pang, Vishal Jhanji; Mechanisms of corneal epithelial degeneration in keratoconus: Histology and microRNA analyses. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5561.
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© ARVO (1962-2015); The Authors (2016-present)
Keratoconus is a bilateral, progressive corneal ectasia associated with irregular astigmatism and decreased visual acuity. We hypothesize that microRNAs (miRNAs) regulate the pathological changes during the development of keratoconus. This study aimed to delineate the miRNA profile of corneal epithelium from keratoconus patients.
A total of 26 corneal epithelium samples were obtained from subjects who underwent surface ablation or collagen crosslinking. The expression of miRNAs was determined using the microRNA expression microarray (version 19.0, Agilent Technologies) and analyzed using the GeneSpring analysis software (version 13.0, Agilent Technologies). Differentially expressed miRNAs were validated by the TaqMan® quantitative microRNA assays (Applied Biosystems). The miRNA target genes were predicted using TargetScan and their biological roles were analyzed by gene ontology analysis (DAVID, version 6.8; National Institute of Health) and pathway analysis (FunRich, version 2.1.2).
Histological assessment by hematoxylin and eosin staining showed that the corneal epithelium in keratoconus patients was thinner with loosely packed cells as compared to control subjects. Microarray analysis demonstrated that 137 of 2006 human miRNAs had more than 1.5-fold expression changes, among which 11 showed significant differential expression in the keratoconus epithelium, compared to the control epithelium (corrected p < 0.05). TaqMan PCR validated 7 miRNAs (hsa-miR-138-5p, hsa-miR-146b-5p, hsa-miR-151a-3p, hsa-miR-151a-5p, hsa-miR-181a-2-3p, hsa-miR-185-5p, and hsa-miR-28-5p) that were significantly downregulated in the keratoconus epithelium (p < 0.05). Gene ontology analysis demonstrated that the predicted miRNA target genes could be involved in cell junction, cell division and cell migration. Pathway analysis suggested that IGF-1 pathway could be regulated by the differentially expressed miRNAs and their target genes.
The miRNA profile of keratoconus corneal epithelium suggested that the regenerative properties of corneal epithelium are affected in keratoconus. In addition, the differentially expressed miRNAs can be regarded as a novel biomarker for keratoconus diagnosis.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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