Distinct Transcriptomic Profiles of Cultured Anterior and Posterior Populations of Human Infant Scleral Fibroblasts: Including Dopamine Receptors.

Purpose: The transcriptomic profiling of scleral fibroblasts remains largely unexplored. To elucidate their heterogeneity, we performed single-cell RNA sequencing (scRNA-seq) on primary infant scleral fibroblasts.

Methods: Primary scleral fibroblasts, cultured at passage 2 from the anterior, equatorial, and posterior regions of infant sclera (3 months to 2 years of age) were subjected to scRNA-seq using the 10x Genomics platform. In-depth analysis revealed distinct transcriptomic profiles between anterior and posterior scleral fibroblasts, including differential expression of dopamine (DA) receptors, which was subsequently validated both in vitro and in situ. Furthermore, the regulatory role of DA in scleral remodeling was assessed using an in vitro collagen gel contraction assay, and the involvement of DA receptor activity and expression in this process was further explored through pharmacological manipulation and gene silencing approaches.

Results: Infant scleral fibroblasts have anterior and posterior subpopulations, each exhibiting distinct transcriptomic profiles. Anterior scleral fibroblasts show increased expression of D1-like receptors, but posterior scleral fibroblasts exhibit elevated expression of D2-like receptors. D1-like receptor activity enhances the inhibitory effect of DA on scleral remodeling in anterior sclera, whereas D2-like receptor activity, particularly that of DRD2 in the posterior sclera, counteracts this effect. Gene silencing of DRD4 significantly enhances DA-mediated inhibition of scleral remodeling in the posterior sclera.

Conclusions: To our knowledge, this study presents the first comprehensive transcriptomic profiling of infant scleral fibroblasts, revealing their heterogeneity. The investigation of the regulatory role of DA receptor activity and expression in DA-mediated inhibition of scleral fibroblast contraction provides new insights into how DA signaling modulates scleral remodeling.