Integrated proteomic and nitrosylomic profiling suggests a role for S-nitrosylation in choroidal dysregulation during myopia pathogenesis.

Abstract

BACKGROUND: Myopia, a global health burden, is associated with choroidal dysfunction, but the role of post-translational modifications, specifically S-nitrosylation (SNO), in its pathogenesis remains unclear. This study aimed to characterize choroidal S-nitrosylation and proteomic changes in lens-induced myopia (LIM) to identify SNO-driven regulatory pathways. METHODS: Myopia was induced in guinea pigs by unilateral -10 D lens wear (LIM group), with contralateral eyes as normal controls (NC). Ocular changes were assessed by axial length (AL) and refractive error measurements. Choroidal thickness was evaluated via Hematoxylin and Eosin (H&E) staining. Global S-nitrosylation changes were detected by the biotin-switch assay coupled with Western blotting. Integrated proteomic and S-nitrosylomic profiling of choroidal tissues was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Bioinformatic analyses included functional enrichment analysis and integrative nine-quadrant analysis to identify proteins regulated primarily via S-nitrosylation independent of abundance changes. RESULTS: The LIM model induced significant axial elongation (normalized AL elongation: 0.40 ± 0.68 mm) and a myopic shift (-7.11 ± 1.22 D), accompanied by significant choroidal thinning (49.69 ± 8.67 μm in LIM vs. 70.96 ± 8.90 μm in NC, P = 0.00004). Total choroidal S-nitrosylated protein levels were significantly upregulated in LIM. Integrated dual-omics analysis identified 1293 proteins (corresponding to 1651 modification sites) with significant SNO changes without concomitant protein abundance alterations. Among these, 711 proteins (910 sites) showed upregulated S-nitrosylation in the LIM group. Functional enrichment analysis of these proteins implicated key pathways including Cytoskeleton in muscle cells, Synaptic vesicle cycle, and Ferroptosis. Critical candidates such as HSPG2, FN1, SPTBN1, NSF, and GPX4 were prioritized, suggesting their involvement in extracellular matrix integrity, neurovascular communication, and oxidative stress defense. CONCLUSION: This study provides the first integrated map of choroidal proteome and S-nitrosylome in myopia, establishing S-nitrosylation as a pivotal post-translational regulatory layer. The data suggest that SNO-mediated dysregulation of cytoskeletal integrity, synaptic signaling, and ferroptosis pathways may contribute to choroidal thinning and dysfunction during myopia progression. These findings nominate specific SNO-modified proteins and their associated pathways as novel potential therapeutic targets for myopia intervention. Future work should focus on the functional validation of the identified SNO sites.