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Bharanidharan Devarajan, Hemadevi Boomiraj, VIDYARANI MOHANKUMAR, Lalitha Prajna; Human Corneal microRNA Expression Profile in Fungal Keratitis. Invest. Ophthalmol. Vis. Sci. 2015;56(7 ):1884.
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© ARVO (1962-2015); The Authors (2016-present)
Keratitis can progress rapidly with corneal ulceration through pathological wound healing within 24-48 hours. The predominant cause of corneal ulceration in India is fungi, may be responsible for 60-70% of infectious keratitis cases. Many of the fungal keratitis cases are refractory to medical treatment and will require corneal transplantation. MicroRNAs (miRNAs) are small, stable non-coding RNA molecules with regulatory function and marked tissue specificity that post-transcriptionally regulate gene expression, however their role in fungal keratitis remain unknown. Here, our purpose is to identify the miRNAs in human cornea from fungal keratitis patients and understand their key role in regulation of pathogenesis.
Corneal samples from normal cadaver (n=3) and fungal keratitis (n=5) patients were pooled separately. Deep sequencing was done using illumina platform to identify miRNA profile. NOISeq R package was applied to identify the differentially expressed significant miRNAs. Select miRNAs were validated by Real-time RT-PCR (Q-PCR). The regulatory functions of miRNAs were predicted by combining miRNA target genes and pathway analysis. mRNA expression levels of select target genes were further analysed by Q-PCR.
Using deep sequencing, seventy five miRNAs were identified as differentially expressed with fold change >2 and the probability score >0.9 in fungal keratitis corneas. MiRNAs with same isomiRs, showing high fold difference (>5), were confirmed by Q-PCR. In addition, we predicted their role in regulating target genes in several pathways. Among those, miR-21-5p, miR-223-3p, miR-146b-5p, miR-155-5p, miR-511-5p were found to be involved in inflammatory and immune responses, regulating Toll like receptor signalling pathways, which is of particular interest. MiR-451a with an increased expression in keratitis may have a role in wound healing by targeting Macrophage Migration Inhibitory Factor (MIF). Further, we highlighted that Neurotrophin signalling pathway may play a role in wound healing process. One novel miRNA was detected only in keratitis cornea.
Several miRNAs with high expression in fungal keratitis corneas point towards their potential role in regulation of pathogenesis. Further insights in understanding miRNAs role in wound healing and inflammation may help design new therapeutic strategies.
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