N. sphaeroides phycocyanin subunit Ns-α and Ns-β improve C. elegans antioxidative capacity via ROS-related regulation
Abstract
Oxidative stress and damage to macromolecules due to free radicals are commonly considered factors that can impair health. Phycocyanin, a natural pigment-apoprotein complex composed of protein α- and β-subunits with attached linear tetrapyrrole chromophores, has health benefits such as reducing the impact of reactive oxygen species (ROS) . However, the potential functions of the subunit proteins in vitro remain unexplored. In this study, bacterial expression vectors were separately constructed to induce two engineering subunit proteins, Ns-α and Ns-β, with genes derived from Nostoc sphaeroides (Gexianmi), a valuable resource with both medicinal and edible virtues. These engineering proteins were then examined for their potential to enhance antioxid ative capacity in C. elegans. A proper concentration of the proteins Ns-α and Ns-β in vitro exhibited 2, 2-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity. While there were no other observed effects on the nematodes, those treated with the proteins showed significant improvements in motility and reduced levels of lipofuscin compared to the control group. Furthermore, the treated nematodes demonstrated increased resistance to oxidation, as evidenced by the higher survivals under oxidative conditions induced by 5 mM H2O2. Notably, the treated nematodes exhibited decline in endogenous ROS levels, and the redox-related genes, such as SOD-3 and CAT-1, were down-regulated following consumption of the engineering proteins. These findings suggest that engineering proteins Ns-α and Ns-β improve the antioxidative capacity of C. elegans by modulatin g ROS-related regulation, making them potential modulators in responding to oxidative stressors.