PMID- 36244663 OWN - NLM STAT- MEDLINE DCOM- 20221228 LR - 20221228 IS - 2212-8778 (Electronic) IS - 2212-8778 (Linking) VI - 66 DP - 2022 Dec TI - Hindbrain insulin controls feeding behavior. PG - 101614 LID - S2212-8778(22)00183-1 [pii] LID - 10.1016/j.molmet.2022.101614 [doi] LID - 101614 AB - OBJECTIVE: Pancreatic insulin was discovered a century ago, and this discovery led to the first lifesaving treatment for diabetes. While still controversial, nearly one hundred published reports suggest that insulin is also produced in the brain, with most focusing on hypothalamic or cortical insulin-producing cells. However, specific function for insulin produced within the brain remains poorly understood. Here we identify insulin expression in the hindbrain's dorsal vagal complex (DVC), and determine the role of this source of insulin in feeding and metabolism, as well as its response to diet-induced obesity in mice. METHODS: To determine the contribution of Ins2-producing neurons to feeding behavior in mice, we used the cross of transgenic RipHER-cre mouse and channelrhodopsin-2 expressing animals, which allowed us to optogenetically stimulate neurons expressing Ins2 in vivo. To confirm the presence of insulin expression in Rip-labeled DVC cells, in situ hybridization was used. To ascertain the specific role of insulin in effects discovered via optogenetic stimulation a selective, CNS applied, insulin receptor antagonist was used. To understand the physiological contribution of insulin made in the hindbrain a virogenetic knockdown strategy was used. RESULTS: Insulin gene expression and presence of insulin-promoter driven fluorescence in rat insulin promoter (Rip)-transgenic mice were detected in the hypothalamus, but also in the DVC. Insulin mRNA was present in nearly all fluorescently labeled cells in DVC. Diet-induced obesity in mice altered brain insulin gene expression, in a neuroanatomically divergent manner; while in the hypothalamus the expected obesity-induced reduction was found, in the DVC diet-induced obesity resulted in increased expression of the insulin gene. This led us to hypothesize a potentially divergent energy balance role of insulin in these two brain areas. To determine the acute impact of activating insulin-producing neurons in the DVC, optic stimulation of light-sensitive channelrhodopsin 2 in Rip-transgenic mice was utilized. Optogenetic photoactivation induced hyperphagia after acute activation of the DVC insulin neurons. This hyperphagia was blocked by central application of the insulin receptor antagonist S961, suggesting the feeding response was driven by insulin. To determine whether DVC insulin has a necessary contribution to feeding and metabolism, virogenetic insulin gene knockdown (KD) strategy, which allows for site-specific reduction of insulin gene expression in adult mice, was used. While chow-fed mice failed to reveal any changes of feeding or thermogenesis in response to the KD, mice challenged with a high-fat diet consumed less food. No changes in body weight were identified, possibly resulting from compensatory reduction in thermogenesis. CONCLUSIONS: Together, our data suggest an important role for hindbrain insulin and insulin-producing cells in energy homeostasis. CI - Copyright (c) 2022 The Authors. Published by Elsevier GmbH.. All rights reserved. FAU - Eerola, Kim AU - Eerola K AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden; Unit of Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Finland. FAU - Longo, Francesco AU - Longo F AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Reinbothe, Thomas M AU - Reinbothe TM AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Richard, Jennifer E AU - Richard JE AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Shevchouk, Olesya T AU - Shevchouk OT AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Lopez-Ferreras, Lorena AU - Lopez-Ferreras L AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Mishra, Devesh AU - Mishra D AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Asker, Mohammed AU - Asker M AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Tolo, Johan AU - Tolo J AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Miranda, Caroline AU - Miranda C AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Musovic, Saliha AU - Musovic S AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Olofsson, Charlotta S AU - Olofsson CS AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden. FAU - Rorsman, Patrik AU - Rorsman P AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden; Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK. FAU - Skibicka, Karolina P AU - Skibicka KP AD - Institute for Neuroscience and Physiology, University of Gothenburg, Sweden; Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Sweden; Department of Nutritional Sciences and The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA. Electronic address: Karolina.Skibicka@neuro.gu.se. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20221013 PL - Germany TA - Mol Metab JT - Molecular metabolism JID - 101605730 RN - 0 (Channelrhodopsins) RN - 0 (Insulin) RN - EC 2.7.10.1 (Receptor, Insulin) SB - IM MH - Animals MH - Mice MH - Rats MH - Channelrhodopsins/metabolism MH - Feeding Behavior MH - Hyperphagia/metabolism MH - *Insulin/metabolism MH - Mice, Transgenic MH - Obesity/metabolism MH - *Receptor, Insulin/metabolism MH - Rhombencephalon/metabolism PMC - PMC9637798 OTO - NOTNLM OT - Diet-induced obesity OT - Dorsal vagal complex OT - Food intake OT - Hindbrain OT - Insulin EDAT- 2022/10/17 06:00 MHDA- 2022/12/21 06:00 PMCR- 2022/10/13 CRDT- 2022/10/16 19:48 PHST- 2022/06/02 00:00 [received] PHST- 2022/10/10 00:00 [revised] PHST- 2022/10/11 00:00 [accepted] PHST- 2022/10/17 06:00 [pubmed] PHST- 2022/12/21 06:00 [medline] PHST- 2022/10/16 19:48 [entrez] PHST- 2022/10/13 00:00 [pmc-release] AID - S2212-8778(22)00183-1 [pii] AID - 101614 [pii] AID - 10.1016/j.molmet.2022.101614 [doi] PST - ppublish SO - Mol Metab. 2022 Dec;66:101614. doi: 10.1016/j.molmet.2022.101614. Epub 2022 Oct 13.