생명과학과에서 아래와 같이 세미나를 실시합니다.

많은 관심과 참여 부탁드립니다.

일시: 2023년 5월 18일 금요일 17:00

장소: 원천관 242호

연사: 오양균 교수(이화여자대학교 생명과학과)

주제: Deciphering the function of internal nutrient-sensor

주관: 기초과학연구소(자율운영 중점연구소지원사업)

Deciphering the function of internal nutrient-sensor

Animals are able to sense their internal metabolic status and adjust their metabolism and feeding behaviors to cope with environmental changes. Although the function of internal sensors is essential for maintaining metabolic homeostasis, we could not fully understand them because of their complexity. I found that insulin and glucagon release in Drosophila is controlled by a pair of glucose-sensing neurons in the brain (Oh et al., 2019, Nature). When glucose levels are elevated, the stimulated glucose-sensing neurons send excitatory signals to insulin-producing cells (IPCs) and simultaneously send inhibitory signals to glucagon-producing cells. The signaling cascade from those neurons increases and decreases the secretion of insulin and glucagon, respectively. This finding is the first discovery of the neuronal control of glucose homeostasis, coordinated by insulin and glucagon secretion. Additionally, I found that the mechanosensory Piezo channel monitors the stomach/crop stretch following food ingestion and conveys the information to the brain, thereby inhibiting the glucose-evoked response of nutrient-sensing neurons and preventing food overconsumption (Oh et al., 2021, Neuron). This finding gave us a comprehensive understanding of how the internal mechanosensory system monitors the influx of food in the gastrointestinal tract and regulates feeding behavior by controlling the function of glucose-sensing neurons.

Maintaining protein homeostasis is essential for the survival and reproduction of animals. While it is known that the specific taste-receptors recognize the dietary protein in the food, it is unclear how animals detect and respond to the deprivation of dietary protein. The previous study reported that the CNMa peptide is released from the enterocytes in the Drosophila midgut during protein deprivation. Then CNMa peptide guide animals prefer essential amino acids (EAAs) rather than non-essential amino acids (NEAAs) (Kim et al., 2021, Nature). However, it is not fully understood how the CNMa signaling pathway influences the brain to increase protein or EAAs specific appetite during protein starvation. Here, we identified two distinct CNMa receptor-expressing brain regions that regulate protein or carbohydrate appetite to maximize protein feeding during protein deprivation. We show that CNMa signaling suppresses carbohydrate feeding by inhibiting the glucose response of DH44 neurons in protein-starved flies. Simultaneously, a specific population of ellipsoid body (EB) neurons express CNMa receptor activated by CNMa peptide and increase protein appetite in protein-deprived flies. These findings show that CNMa peptide is secreted during protein deprivation, suppresses carbohydrate feeding by inhibiting DH44 neurons, and evokes protein feeding by activating a specific population of EB neurons in the fly brain.