Key molecular networks underlying retinol's biphasic effects on cell proliferation through multi-omics integrative analysis using genome-scale metabolic modeling.

Retinol is widely used in skin anti-aging, yet its effects exhibit significant concentration dependence. However, the underlying biphasic mechanism, that is low concentrations promote cell proliferation while high concentrations are inhibitory, remains incompletely understood. Here, we employed multi-omics analysis and genome-scale metabolic models (GEMs) to systematically infer the key molecular networks underlying the distinct effects of retinol concentrations on human foreskin fibroblasts (HFFs). Our results suggest that low retinol concentrations appear to promote proliferation by activating the canonical retinoic acid signaling pathway and inducing sophisticated metabolic reprogramming. This reprogramming appears to involve prioritizing the coenzyme NADPH for retinol processing and antioxidant defense, which is associated with a compensatory suppression of NADPH-consuming cholesterol biosynthesis. This metabolic shift may foster a favorable intracellular environment for growth. Conversely, high concentrations are linked to a multi-system injury cascade. The observed key feature likely involves significant oxidative stress, associated with the buildup of toxic metabolic intermediates and a pro-inflammatory lipid storm marked by elevated leukotrienes. These stress responses align with the signatures of ferroptosis, a form of programmed cell death characterized by glutathione (GSH) defense system collapse and downregulation of the key regulator GPX4. Our findings suggest a potential mechanistic transition from a state of metabolic optimization to the activation of stress-induced injury pathways in response to varying retinol concentrations. This study provides a systems-level framework for understanding retinol's biphasic effects and highlights key regulatory nodes (e.g., DHRS3, GCLM) as potential targets for future research. These insights could contribute to developing safer and more effective retinol-based formulations in cosmetic and dermatological applications.