Phlorizin Ameliorates Amyloid-β Toxicity and Enhances Fatty Acid β-Oxidation in Caenorhabditis elegans via NHR-49-Dependent Pathway

Phlorizin (PHZ) is a glucoside of phloretin, belonging to the dihydrochalcone class within flavonoids; It is one of the active ingredients of the plant Cynomorium, and it has been shown that PHZ can regulate lipid metabolism disorders as well as having anti-aging properties. However, no studies have investigated whether PHZ ameliorates Aβ-induced toxicity in Alzheimer's disease (AD) by regulating fatty acid β-oxidation. This study aims to investigate the effects of PHZ on the regulation of fatty acid β-oxidation and resistance to Aβ-associated toxicity on the AD <i>Caenorhabditis elegans</i> and the mechanisms of action. Wild-type N2 and AD model CL4176 <i>C. elegans</i> were used; lifespan, heat stress resistance, chronic paraquat stress, reactive oxygen species (ROS), behavioral performance, and lipofuscin accumulation assays were examined to evaluate the anti-aging effects; and non-esterified fatty acid (NEFA), triglyceride (TG) and lipidomic contents were quantified after PHZ treatment. The detection of genes related to fatty acid β-oxidation pathways was performed using qRT-PCR. <i>nhr-49</i> knockout mutant RB1716; and GFP-binding mutants PMD150 WBM170 were used to observe the effect of PHZ on NHR-49 pathways, and molecular docking studies were performed by combining PHZ with NHR-49 proteins. Results showed that PHZ improved worms' survival and delayed senescence, as demonstrated by enhanced performance in lifespan, heat stress, ROS, and paraquat assays and chronic paraquat assays; PHZ also reduced lipid accumulation in worms, affected the unsaturated fatty acid pathway, and significantly increased the expression of fatty acid metabolism-related genes <i>nhr-49</i>, <i>acs-2</i>, and <i>cpt-5</i>, and can be tightly coupled to NHR-49 targets. PHZ may play an anti-Aβ toxicity role by regulating lipid metabolism disorders through the NHR-49-related pathway and anti-aging in AD worms.