Regulation of lipid dysmetabolism and neuroinflammation linked with Alzheimer's disease through modulation of Dgat2

Abstract

Alzheimers disease (AD), an age-associated neurodegenerative disorder, is characterized by progressive cognitive decline, amyloid-{beta} (A{beta}) deposition, lipid dysregulation, and neuroinflammation. Although mutations in the amyloid precursor protein (APP) and accumulation of A{beta}42 are established drivers of pathology, the mechanisms connecting amyloid toxicity with lipid metabolism and inflammatory responses remain poorly understood. Here, we employed complementary Drosophila and mouse models to dissect these relationships. Expression of AppNLG and A{beta}42 in Drosophila resulted in locomotor deficits, disrupted sleep-circadian rhythms, memory impairments, lipid accumulation, synaptic loss, and neuroinflammatory signatures. Comparable lipid metabolic disturbances and inflammatory alterations were detected in the AppNLG-F knock-in mouse model, underscoring their conserved relevance to AD pathogenesis. We further identified diacylglycerol O-acyltransferase 2 (Dgat2), a key enzyme catalyzing the final step of triglyceride synthesis, as a critical modulator of AD-related phenotypes. Dgat2 expression was altered in both animal models and human AD tissues. Notably, panneuronal knockdown of Dgat2 in Drosophila attenuated lipid accumulation, restored synaptic integrity, and ameliorated locomotor and cognitive deficits, while also reducing neuroinflammation. Dgat2 suppression additionally improved sleep and circadian behavior, highlighting its pleiotropic protective effects. Together, these findings demonstrate a mechanistic link between amyloid pathology, lipid dysregulation, and neuroinflammatory processes. Targeting Dgat2 may therefore represent a novel therapeutic strategy to counteract AD-associated metabolic and neuronal dysfunction. The conservation of lipid homeostasis mechanisms across species underscores the translational potential of this approach for delaying or mitigating AD progression.