Decreased scleral Wnt5a^hi fibroblasts exacerbate myopia progression by disrupting extracellular matrix homeostasis in mice

Myopia is a common refractive error with high prevalence; its pathogenesis is poorly understood. Scleral single-cell RNA sequencing is used to determine whether there is an association between phenotypic heterogeneity of scleral fibroblasts and form-deprivation myopia in male mice. The number of unique Wnt5a-positive scleral fibroblasts is markedly lower in the form-deprived eyes, specifically in the temporal inner peripapillary sclera. Inhibition of Wnt5a expression by injection of shWnt5a-AAV within Tenon’s capsule causes increased myopia progression, while decreasing COL1A1 protein content and collagen fibril diameter. Integrating scleral bulk RNA-seq data from shWnt5a-AAV injected male mice with data from scleral single-cell RNA sequencing in form-deprivation myopia mice, implicates the Sparc gene as a key downstream target of the Wnt5a signalling pathway. Tenon’s capsule injection of shSparc-AAV induces myopia, decreases scleral COL1A1 content, and reduces collagen fibril diameter. These results demonstrate that scleral-specific fibroblasts manifesting high Wnt5a expression (Wnt5a^hi fibroblast) modulate homeostasis of the extracellular matrix, thus promoting myopia progression.