title: Octopamine connects nutrient cues to lipid metabolism upon nutrient deprivation.
abstract: Starvation is probably the most common stressful situation in nature. In vertebrates, elevation of the biogenic amine norepinephrine levels is common during starvation. However, the precise role of norepinephrine in nutrient deprivation remains largely unknown. We report that in the free-living nematode Caenorhabditis elegans, up-regulation of the biosynthesis of octopamine, the invertebrate counterpart of norepinephrine, serves as a mechanism to adapt to starvation. During nutrient deprivation, the nuclear receptor DAF-12, known to sense nutritional cues, up-regulates the expression of tbh-1 that encodes tyramine β-hydroxylase, a key enzyme for octopamine biosynthesis, in the RIC neurons. Octopamine induces the expression of the lipase gene lips-6 via its receptor SER-3 in the intestine. LIPS-6, in turn, elicits lipid mobilization. Our findings reveal that octopamine acts as an endocrine regulator linking nutrient cues to lipolysis to maintain energy homeostasis, and suggest that such a mechanism may be evolutionally conserved in diverse organisms.
authors.affiliation: State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Tao
authors.affiliation: State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Yi-Cheng
authors.identifier: 0000-0002-9585-6279
authors.initials: YC
authors.lastname: Ma
authors.affiliation: State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan 650091, China.; College of Basic Medicine, Yunnan University of Traditional Chinese Medicine, Kunming, Yunnan 650500, China.
authors.forename: Zhong-Shan
authors.initials: ZS
authors.lastname: Yang
authors.affiliation: State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Cheng-Gang
authors.initials: CG
authors.lastname: Zou
authors.affiliation: State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Ke-Qin
authors.identifier: 0000-0002-3190-5326
authors.initials: KQ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism; D003463:Cues; D005502:Food; D005786:Gene Expression Regulation; D008049:Lipase / Q000235:genetics / Q000378:metabolism; D050356:Lipid Metabolism; D053858:Metabolic Networks and Pathways; D009747:Nutritional Physiological Phenomena; D009655:Octopamine / Q000378:metabolism*; D011485:Protein Binding; D013217:Starvation
chemical_list: D029742:Caenorhabditis elegans Proteins; D009655:Octopamine; D008049:Lipase
keywords: C. elegans; DAF-12; Octopamine; lipid hydrolysis; starvation