Hunter-Manseau Florence, Cormier Simon B, Strang Rebekah, Pichaud Nicolas
Department of Chemistry and Biochemistry, Université de Moncton, Moncton, New Brunswick, Canada.
New Brunswick Centre for Precision Medicine, Moncton, New Brunswick, Canada.
Insect Sci. 2024 Dec;31(6):1770-1788. doi: 10.1111/1744-7917.13355. Epub 2024 Mar 21.
Changes in diet type and nutrient availability can impose significant environmental stress on organisms, potentially compromising physiological functions and reproductive success. In nature, dramatic fluctuations in dietary resources are often observed and adjustments to restore cellular homeostasis are crucial to survive this type of stress. In this study, we exposed male Drosophila melanogaster to two modulated dietary treatments: one without a fasting period before exposure to a high-fat diet and the other with a 24-h fasting period. We then investigated mitochondrial metabolism and molecular responses to these treatments. Exposure to a high-fat diet without a preceding fasting period resulted in disrupted mitochondrial respiration, notably at the level of complex I. On the other hand, a short fasting period before the high-fat diet maintained mitochondrial respiration. Generally, transcript abundance of genes associated with mitophagy, heat-shock proteins, mitochondrial biogenesis, and nutrient sensing pathways increased either slightly or significantly following a fasting period and remained stable when flies were subsequently put on a high-fat diet, whereas a drastic decrease of almost all transcript abundances was observed for all these pathways when flies were exposed directly to a high-fat diet. Moreover, mitochondrial enzymatic activities showed less variation after the fasting period than the treatment without a fasting period. Overall, our study sheds light on the mechanistic protective effects of fasting prior to a high-fat diet and highlights the metabolic flexibility of Drosophila mitochondria in response to abrupt dietary changes and have implication for adaptation of species to their changing environment.
饮食类型和营养可利用性的变化会给生物体带来巨大的环境压力，可能损害其生理功能和繁殖成功率。在自然界中，经常会观察到饮食资源的剧烈波动，而恢复细胞内稳态的调节对于在这种压力下生存至关重要。在本研究中，我们将雄性黑腹果蝇暴露于两种经过调节的饮食处理中：一种在暴露于高脂饮食前没有禁食期，另一种有24小时禁食期。然后，我们研究了线粒体代谢以及对这些处理的分子反应。暴露于无前期禁食期的高脂饮食会导致线粒体呼吸紊乱，尤其是在复合体I水平。另一方面，高脂饮食前的短期禁食可维持线粒体呼吸。一般来说，与线粒体自噬、热休克蛋白、线粒体生物发生和营养感应途径相关的基因转录丰度在禁食期后略有或显著增加，并且当果蝇随后摄入高脂饮食时保持稳定，而当果蝇直接暴露于高脂饮食时，所有这些途径的几乎所有转录丰度都急剧下降。此外，禁食期后的线粒体酶活性变化小于无禁食期的处理。总体而言，我们的研究揭示了高脂饮食前禁食的机制性保护作用，并突出了果蝇线粒体在应对突然的饮食变化时的代谢灵活性，对物种适应不断变化的环境具有启示意义。
