Dissecting metabolic regulation of behaviors and physiology during aging in Drosophila.

Abstract

Aging disrupts physiological and behavioral homeostasis, largely driven by one-carbon metabolism, mitochondrial, and metabolic imbalance. To elucidate the roles of conserved metabolic and mitochondrial genes in age-related decline, we employed genetic manipulations in vivo using Drosophila melanogaster models, in a cell-autonomous and non-cell-autonomous manner. By using panneuronal and indirect flight muscle (IFM) specific drivers, we assessed the impact of gene knockdown (KD) or overexpression (OE) on sleep-circadian rhythms, locomotion, and lipid metabolism in a cell-autonomous and non-cell-autonomous manner to address bidirectional neuro-muscle communications. KD of genes such as SdhD and Gnmt leads to a decrease in flight performance, especially in 6 weeks with both drivers. Panneuronal knockdown of genes did not impact the locomotory performance. Whereas knockdown of mAcon1, LSD2, Ampkα, Ald, and Adsl genes showed reduced flight performance, with only IFM-specific driver emphasizing the cell-autonomous role of metabolic genes. Panneuronal KD of Ald, GlyP, mAcon1, and Gnmt genes showed increased total sleep, reduced activity, while Adsl and Ogdh knockdown led to sleep fragmentation, in a mid-age suggests cell-autonomous impact. Functional analysis of AMPK signaling via overexpression and knockdown of Ampkα, as well as expression of the mutant overexpression SNF1A and its kinase-dead mutant, revealed kinase-dependent, age- and tissue-specific modulation of sleep and activity rhythms. Lipid analysis showed that panneuronal overexpression of Ampkα altered lipid droplet number and size in the brain, indicating disrupted lipid homeostasis during aging. These findings on various genes provide us with an understanding of their diverse effects on sleep-activity rhythms, locomotor effects, and communication in cell and non-cell-autonomous roles. Our study emphasizes Ampkα as a central regulator of behavioral and metabolic aging, linking neuronal energy sensing, motor function, and lipid dynamics, and offers mechanistic insights into tissue-specific metabolic regulation with potential relevance for interventions targeting age-related decline and neurodegeneration.