iTRAQ-Based Proteomic Profiling of Skin Aging Protective Effects of Tremella fuciformis-Derived Polysaccharides on D-Galactose-Induced Aging Mice

In the present study, a heteromannan primarily composed of mannose, fucose, xylose, glucose, and arabinose at a molar ratio of 4.78:1.18:1:0.82:0.11 containing a low proportion of glucuronic acid with weight-average molecular weights of 3.6 × 10⁶ Da, named NTP, was prepared from the fruiting body of <i>Tremella fuciformis</i>. The anti-skin-aging effects of NTP on d-Galactose-induced aging mice and the biological mechanisms were investigated by an iTRAQ-based proteomics approach. NTP substantially mitigated skin aging characterized by a decreased loss of hydroxyproline and hyaluronic acid and reduced oxidative stress in the skin. Moreover, 43 differentially expressed proteins (DEPs) were identified in response to NTP, of which 23 were up-regulated and 20 were down-regulated. Bioinformatics analysis revealed that these DEPs were mainly involved in the biological functions of cellular and metabolic regulations, immune system responses, and structural components. The findings provided new insights into the biological mechanisms underlying the anti-skin-aging actions of <i>T. fuciformis</i>-derived polysaccharides and facilitated NTP applications in naturally functional foods.