Abstract
Purpose: :
Cellular microRNAs (miRNA) are noncoding RNAs of ~21 nucleotides (nt) that recognize target mRNAs by base pairing and thereby regulate their expression. Recent advances demonstrate that miRNAs play important roles in developmental timing, differentiation, cell proliferation and apoptosis. Although brain specific miR-124, miR-125b and let-7 are expressed in the mouse and rat lens, virtually nothing is known about the spatial and temporal expression profiles of miRNAs in lens development. To provide an overview of the breadth of miRNA expression in the lens, we performed microarray analysis to detect miRNA expression profile in developing as well as adult rat lens epithelial cells (LECs). We also analyzed specific miRNA using human LECs.
Methods: :
All animal experiments were conducted in accordance with the National Institute of Health Guide for the Care and Use of Laboratory Animals and the animal protocol in University of Fukui. To identify miRNA expression profile of LECs, total RNAs were isolated from Sprague-Dawley female rats at gestational days 14, 4 weeks (W) and 14 W. RNA quality control, labeling, hybridization, and scanning were performed by ALLIANCE Biosystems, Inc. (Osaka, Japan) using Agilent rat miRNA array. Real-time PCR was used to validate the microarray results and to analyze the expression of human LECs.
Results: :
By using LECs isolated from rats of different developmental stages or variable ages, we discovered that miRNAs have a wide variety of expression profiles during development or with aging in rat LECs. Expression of several miRNAs, such as let 7a, let 7b let 7c, miR29a, miR 29c, miR126, miR 204, mi339-3P, miR 451, are altered in rat LECs during late embryonic and post-natal development and adult lenses. miRNAs such as let-7b and c were detected in human LECs.
Conclusions: :
Differential expression profiles of miRNAs during development in rat LECs reveals that the modulation of specific miRNA expression may be involved in regulating development and maturity of rat lens. Thus our data provide a significant resource and inspiration to those seeking functional studies of miRNAs in the lens development and differentiation.
Keywords: aging • development • RNAi