Abstract
Polynucleotide (PN), a high-molecular-weight DNA fragment derived from salmon and other fish sources, shows promising anti-aging and regenerative effects on the skin. This study investigated how PN enhances collagen synthesis, focusing on its effect on phosphoenolpyruvate carboxykinase 1 (PCK1) in senescent macrophages and its downstream effects on fibroblasts. Using in vitro senescent cell models and in vivo aged animal models, PN significantly upregulated the adenosine 2A receptor (A2AR), adenylate cyclase (AC), cyclic AMP (cAMP), protein kinase A (PKA), and cAMP response element-binding protein (CREB) in senescent macrophages. This led to increased PCK1 expression, which reduced oxidative stress and promoted M2 macrophage polarization, associated with elevated levels of interleukin-10 and tumor growth factor-β. Conditioned media from PN-treated macrophages enhanced SMAD family member 2 and signal transducer and activator of transcription 3 phosphorylation in senescent fibroblasts, increasing collagen I and III synthesis and reducing nuclear factor-κB activity. In vivo, PN administration elevated expression of the A2AR/AC/PKA/CREB/PCK1 pathway, reduced oxidative stress, increased M2 macrophage markers, and significantly improved collagen density and skin elasticity over time. Use of a PCK1 inhibitor attenuated these effects, highlighting the pivotal role of PCK1. Overall, PN modulates macrophage-fibroblast interactions via the CREB/PCK1 axis, enhancing collagen synthesis and counteracting age-related skin changes. PN has emerged as a promising therapeutic agent for skin rejuvenation by targeting cellular senescence and promoting extracellular matrix restoration.