Hypoxia-driven HIF-1α-dependent glycolysis/lactate-associated signaling promotes autophagy-associated scleral...

Myopic axial elongation is driven by scleral remodeling, yet the metabolic events linking scleral hypoxia to autophagy-associated remodeling remain incompletely defined. We examined whether HIF-1α-dependent glycolytic reprogramming and lactate-associated metabolic stress connect hypoxia to remodeling changes in human scleral fibroblasts (HSFs) and in a guinea pig model of form-deprivation myopia (FDM). RNA sequencing showed significant enrichment of HIF-1 signaling and glycolysis/gluconeogenesis in hypoxic HSFs. Hypoxia increased HIF-1α, HK2, PFKP, and LDHA expression and raised intracellular lactate levels. Inhibition of glycolysis with 2-deoxy-D-glucose (2DG) or pharmacologic inhibition of lactate production with oxamate attenuated hypoxia-associated autophagy and remodeling marker changes. HIF-1α inhibition with acriflavine or siRNA suppressed glycolytic activation and mitigated downstream marker changes. Exogenous lactate partly restored autophagy- and remodeling-associated phenotypes during glycolytic or HIF-1α inhibition without restoring upstream glycolytic enzyme expression. Additional CQ-based flux assays supported that hypoxia enhanced autophagic flux and that lactate further increased CQ-sensitive LC3B II accumulation under hypoxia. pH-controlled experiments showed that sodium lactate under pH-normalized conditions and HCl-mediated acidification produced partially overlapping downstream effects, whereas unadjusted Lactate produced the strongest response, supporting combined contributions from lactate-associated signaling and extracellular acidification. GNE-140, used as an LDH/lactate branch-focused inhibitor, attenuated downstream autophagy- and remodeling-associated changes without materially suppressing upstream glycolytic enzymes, and lactate add-back restored the downstream phenotype. In vivo, subconjunctival 2DG reduced myopic refractive shift, axial elongation, posterior scleral thinning, collagen disorganization, abnormal glycolysis/autophagy/ECM marker expression, and FDM-associated scleral lactate accumulation. These findings support a model in which hypoxia-driven HIF-1α-dependent glycolytic rewiring generates a lactate-enriched acidic microenvironment that contributes to autophagy-associated scleral remodeling in experimental myopia.