PPARα-Mediated Fatty Acid Catabolism in Astrocytes Was Involved in Improvement of Cognitive Dysfunction by Phlorizin in APP/PS1 Mice

Central lipid metabolism disorders are crucial for the development of Alzheimer's disease (AD). Phlorizin (PHZ) improved lipid metabolism abnormalities in AD nematodes, but its mechanism of action in improving AD-related symptoms and whether it can alleviate AD cognitive impairment remain unclear. To elucidate the effects and mechanisms of PHZ on lipid metabolism disorders in an AD model, gavage administration of PHZ for 8 weeks improved cognitive dysfunction and lipid disorders in APPswe/PSEN1dE9 (APP/PS1) mice. Concurrently, in astrocytes induced by palmitic acid (PA)- mediated lipid metabolic disorder, PHZ treatment improved astrocytic lipid accumulation by upregulating the target peroxisome proliferator-activated receptor α (PPARα) and its downstream pathways, thereby promoting astrocytic fatty acid oxidation. We validated PHZ's strong in vitro binding affinity with PPARα. Co-culture systems of lipid-metabolically disordered astrocytes and neurons further demonstrated that PHZ significantly improved neuronal cell viability and reduced intracellular lipid accumulation, thereby decreasing the expression of enzymes associated with β-amyloid protein (Aβ) production. This study demonstrates that gavage administration of PHZ for 2 months improves cognitive deficits and pathological markers in AD mice. Furthermore, at the cellular level, PHZ may exert its effects by enhancing astrocytic lipid metabolism, thereby preventing neuronal lipotoxicity and mitigating AD progression.