Palermo Justin, Keene Alex C, DiAngelo Justin R
Department of Biology, Texas A&M University, College Station, TX, USA.
Division of Science, Penn State Berks, Reading, PA, USA.
Biochem Biophys Rep. 2022 May 14;30:101280. doi: 10.1016/j.bbrep.2022.101280. eCollection 2022 Jul.
The ability of organisms to sense their nutritional environment and adjust their behavior accordingly is critical for survival. Insulin-like peptides (ilps) play major roles in controlling behavior and metabolism; however, the tissues and cells that insulin acts on to regulate these processes are not fully understood. In the fruit fly, , insulin signaling has been shown to function in the fat body to regulate lipid storage, but whether ilps act on the fly brain to regulate nutrient storage is not known. In this study, we manipulate insulin signaling in defined populations of neurons in and measure glycogen and triglyceride storage. Expressing a constitutively active form of the insulin receptor () in the insulin-producing cells had no effect on glycogen or triglyceride levels. However, activating insulin signaling in the Drosulfakinin ()-producing neurons led to triglyceride accumulation and increased food consumption. The expression of , and was increased in flies with activated insulin signaling in the Dsk neurons, which along with the feeding phenotype, may cause the triglyceride storage phenotypes observed in these flies. In addition, expressing a constitutively active in Dsk neurons resulted in decreased sleep in the fed state and less starvation-induced sleep suppression suggesting a role for insulin signaling in regulating nutrient-responsive behaviors. Together, these data support a role for insulin signaling in the -producing neurons for regulating behavior and maintaining metabolic homeostasis.
生物体感知其营养环境并据此调整行为的能力对生存至关重要。胰岛素样肽（ilps）在控制行为和新陈代谢中起主要作用；然而，胰岛素作用于哪些组织和细胞来调节这些过程尚未完全清楚。在果蝇中，胰岛素信号已被证明在脂肪体中发挥作用以调节脂质储存，但ilps是否作用于果蝇大脑来调节营养储存尚不清楚。在本研究中，我们在果蝇特定的神经元群体中操纵胰岛素信号，并测量糖原和甘油三酯的储存情况。在胰岛素产生细胞中表达胰岛素受体（）的组成型活性形式对糖原或甘油三酯水平没有影响。然而，在产生果蝇速激肽（）的神经元中激活胰岛素信号会导致甘油三酯积累并增加食物消耗。在速激肽神经元中胰岛素信号激活的果蝇中，、和的表达增加，这与进食表型一起，可能导致在这些果蝇中观察到的甘油三酯储存表型。此外，在速激肽神经元中表达组成型活性的会导致进食状态下睡眠减少以及饥饿诱导的睡眠抑制减弱，这表明胰岛素信号在调节营养反应性行为中起作用。总之，这些数据支持胰岛素信号在产生速激肽的神经元中对调节行为和维持代谢稳态起作用。
