Ocular-Component-Specific miRNA Expression in a Murine Model of Lens-Induced Myopia

Abstract

To identify tissues and molecules involved in refractive myopic shift and axial length elongation in a murine lens-induced myopia model, we performed a comprehensive analysis of microRNA (miRNA) expression. Three weeks after negative 30 diopter lens fixation on three-week-old C57BL/6J mice, total RNA was extracted from individual ocular components including cornea, iris, lens, retina, retinal pigment epithelium (RPE)/choroid, and sclera tissue. The miRNA expression analysis was pooled from three samples and carried out using Agilent Mouse miRNA Microarray (8 × 60 K) miRBase21.0. The expression ratio was calculated, and differentially expressed miRNAs were extracted, using GeneSpring GX 14.5. Myopic induction showed a significant myopic refractive change, axial elongation, and choroidal thinning. Through the comprehensive miRNA analysis, several upregulated miRNAs (56 in cornea tissue, 13 in iris tissue, 6 in lens tissue, 0 in retina tissue, 29 in RPE/choroid tissue, and 30 in sclera tissue) and downregulated miRNAs (7 in cornea tissue, 28 in iris tissue, 17 in lens tissue, 9 in retina tissue, 7 in RPE/choroid tissue, and 40 in sclera tissue) were observed. Overlapping expression changes in miRNAs were also found in different ocular components. Some of this miRNA dysregulation may be functionally involved in refractive myopia shift and axial length elongation.

Keywords: lens-induced myopia; miRNA; ocular components.

Figure 1

Myopia induction in mice using a negative 30 diopter (D) lens. Changes in (a) refraction and (b) axial length over three weeks are shown as a comparison between normal and negative 30 D lens-wearing eyes (n = 3). Data are presented as the mean ± SD. *** p < 0.001; Student’s t-test. (c) A representative optical coherent tomography (OCT) image showing each ocular component.

Figure 2

Changes in retina and choroid thickness during the period of lens-induced myopia. The changes in (a) retina and (b) choroid thickness over a three-week-period are shown as a comparison between normal and negative 30 D lens-wearing eyes (n = 3). Data are presented as the mean ± SD. * p < 0.05; Student’s t-test.

Figure 3

Ocular component tissues. The individual components of the eyeball are shown as separated into the cornea, iris, lens, retina, retinal pigment epithelium (RPE)/choroid, and sclera. The RPE/choroid and the sclera components were removed as delicately as possible using surgical scalpels.

Figure 4

Corneal miRNAs affected by myopia induction. The corneal miRNAs whose expression was affected by myopia induction are listed as upregulated (left) and downregulated (right).

Figure 5

Iris miRNAs affected by myopia induction. The iris miRNAs whose expression was affected by myopia induction are listed as upregulated (left) and downregulated (right).

Figure 6

Lens miRNAs affected by myopia induction. The lens miRNAs whose expression was affected by myopia induction are listed as upregulated (left) and downregulated (right).

Figure 7

Retinal miRNAs affected by myopia induction. The retinal miRNAs whose expression was affected by myopia induction are listed as upregulated (left) and downregulated (right). Note that no upregulated miRNAs were detected (n.d.).

Figure 8

Retinal pigment epithelium (RPE)/choroidal miRNAs affected by myopia induction. The RPE/choroidal miRNAs whose expression was affected by myopia induction are listed as upregulated (left) and downregulated (right).

Figure 9

Scleral miRNAs affected by myopia induction. The scleral miRNAs whose expression was affected by myopia induction are listed as upregulated (left) and downregulated (right).