1
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Zhu Y, Meerschaert KA, Galvan-Pena S, Bin NR, Yang D, Basu H, Kawamoto R, Shalaby A, Liberles SD, Mathis D, Benoist C, Chiu IM. A chemogenetic screen reveals that Trpv1-expressing neurons control regulatory T cells in the gut. Science 2024; 385:eadk1679. [PMID: 39088603 DOI: 10.1126/science.adk1679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 03/21/2024] [Accepted: 06/03/2024] [Indexed: 08/03/2024]
Abstract
Neuroimmune cross-talk participates in intestinal tissue homeostasis and host defense. However, the matrix of interactions between arrays of molecularly defined neuron subsets and of immunocyte lineages remains unclear. We used a chemogenetic approach to activate eight distinct neuronal subsets, assessing effects by deep immunophenotyping, microbiome profiling, and immunocyte transcriptomics in intestinal organs. Distinct immune perturbations followed neuronal activation: Nitrergic neurons regulated T helper 17 (TH17)-like cells, and cholinergic neurons regulated neutrophils. Nociceptor neurons, expressing Trpv1, elicited the broadest immunomodulation, inducing changes in innate lymphocytes, macrophages, and RORγ+ regulatory T (Treg) cells. Neuroanatomical, genetic, and pharmacological follow-up showed that Trpv1+ neurons in dorsal root ganglia decreased Treg cell numbers via the neuropeptide calcitonin gene-related peptide (CGRP). Given the role of these neurons in nociception, these data potentially link pain signaling with gut Treg cell function.
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Affiliation(s)
- Yangyang Zhu
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Kimberly A Meerschaert
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Silvia Galvan-Pena
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Na-Ryum Bin
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Daping Yang
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Himanish Basu
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Ryo Kawamoto
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Amre Shalaby
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Stephen D Liberles
- Howard Hughes Medical Institute, Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Diane Mathis
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Christophe Benoist
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Isaac M Chiu
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
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2
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Li Y, Kim M, Jiang L, Baron L, Faulkner LD, Olson DP, Li X, Gannot N, Li P, Rui L. SH2B1 Defends Against Energy Imbalance, Obesity, and Metabolic Disease via a Paraventricular Hypothalamus→Dorsal Raphe Nucleus Neurocircuit. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2400437. [PMID: 38885417 PMCID: PMC11336965 DOI: 10.1002/advs.202400437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 05/01/2024] [Indexed: 06/20/2024]
Abstract
SH2B1 mutations are associated with obesity, type 2 diabetes, and metabolic dysfunction-associated steatotic liver disease (MASLD) in humans. Global deletion of Sh2b1 results in severe obesity, type 2 diabetes, and MASLD in mice. Neuron-specific restoration of SH2B1 rescues the obesity phenotype of Sh2b1-null mice, indicating that the brain is a main SH2B1 target. However, SH2B1 neurocircuits remain elusive. SH2B1-expressing neurons in the paraventricular hypothalamus (PVHSH2B1) and a PVHSH2B1→dorsal raphe nucleus (DRN) neurocircuit are identified here. PVHSH2B1 axons monosynaptically innervate DRN neurons. Optogenetic stimulation of PVHSH2B1 axonal fibers in the DRN suppresses food intake. Chronic inhibition of PVHSH2B1 neurons causes obesity. In male and female mice, either embryonic-onset or adult-onset deletion of Sh2b1 in PVH neurons causes energy imbalance, obesity, insulin resistance, glucose intolerance, and MASLD. Ablation of Sh2b1 in the DRN-projecting PVHSH2B1 subpopulation also causes energy imbalance, obesity, and metabolic disorders. Conversely, SH2B1 overexpression in either total or DRN-projecting PVHSH2B1 neurons protects against diet-induced obesity. SH2B1 binds to TrkB and enhances brain-derived neurotrophic factor (BDNF) signaling. Ablation of Sh2b1 in PVHSH2B1 neurons induces BDNF resistance in the PVH, contributing to obesity. In conclusion, these results unveil a previously unrecognized PVHSH2B1→DRN neurocircuit through which SH2B1 defends against obesity by enhancing BDNF/TrkB signaling.
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Affiliation(s)
- Yuan Li
- Department of Molecular & Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | - Min‐Hyun Kim
- Department of Molecular & Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- College of Health SolutionsArizona State UniversityPhoenixAZ85004USA
| | - Lin Jiang
- Department of Molecular & Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | - Lorelei Baron
- Department of Molecular & Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | - Latrice D. Faulkner
- Department of PediatricsUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | - David P. Olson
- Department of Molecular & Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- Department of PediatricsUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- Elizabeth Weiser Caswell Diabetes InstituteUniversity of MichiganAnn ArborMI48109USA
| | - Xingyu Li
- Life Sciences InstituteUniversity of MichiganAnn ArborMI48109USA
| | - Noam Gannot
- Life Sciences InstituteUniversity of MichiganAnn ArborMI48109USA
- Department of Biologic and Materials SciencesSchool of DentistryUniversity of MichiganAnn ArborMI48109USA
| | - Peng Li
- Department of Molecular & Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- Life Sciences InstituteUniversity of MichiganAnn ArborMI48109USA
- Department of Biologic and Materials SciencesSchool of DentistryUniversity of MichiganAnn ArborMI48109USA
| | - Liangyou Rui
- Department of Molecular & Integrative PhysiologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- Elizabeth Weiser Caswell Diabetes InstituteUniversity of MichiganAnn ArborMI48109USA
- Division of Gastroenterology and HepatologyDepartment of Internal MedicineUniversity of Michigan Medical SchoolAnn ArborMI48109USA
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3
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Sun Q, van de Lisdonk D, Ferrer M, Gegenhuber B, Wu M, Park Y, Tuveson DA, Tollkuhn J, Janowitz T, Li B. Area postrema neurons mediate interleukin-6 function in cancer cachexia. Nat Commun 2024; 15:4682. [PMID: 38824130 PMCID: PMC11144211 DOI: 10.1038/s41467-024-48971-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 05/20/2024] [Indexed: 06/03/2024] Open
Abstract
Interleukin-6 (IL-6) has been long considered a key player in cancer cachexia. It is believed that sustained elevation of IL-6 production during cancer progression causes brain dysfunctions, which ultimately result in cachexia. However, how peripheral IL-6 influences the brain remains poorly understood. Here we show that neurons in the area postrema (AP), a circumventricular structure in the hindbrain, is a critical mediator of IL-6 function in cancer cachexia in male mice. We find that circulating IL-6 can rapidly enter the AP and activate neurons in the AP and its associated network. Peripheral tumor, known to increase circulating IL-6, leads to elevated IL-6 in the AP, and causes potentiated excitatory synaptic transmission onto AP neurons and AP network hyperactivity. Remarkably, neutralization of IL-6 in the brain of tumor-bearing mice with an anti-IL-6 antibody attenuates cachexia and the hyperactivity in the AP network, and markedly prolongs lifespan. Furthermore, suppression of Il6ra, the gene encoding IL-6 receptor, specifically in AP neurons with CRISPR/dCas9 interference achieves similar effects. Silencing Gfral-expressing AP neurons also attenuates cancer cachectic phenotypes and AP network hyperactivity. Our study identifies a central mechanism underlying the function of peripheral IL-6, which may serve as a target for treating cancer cachexia.
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Affiliation(s)
- Qingtao Sun
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Daniëlle van de Lisdonk
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
- Center for Neuroscience, University of Amsterdam, Amsterdam, the Netherlands
| | - Miriam Ferrer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Bruno Gegenhuber
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Melody Wu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Youngkyu Park
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - David A Tuveson
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Jessica Tollkuhn
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Tobias Janowitz
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Bo Li
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, 310024, Zhejiang, China.
- School of Life Sciences, Westlake University, Hangzhou, 310024, Zhejiang, China.
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, 310024, Zhejiang, China.
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4
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Liu H, Liu Z, Wong HK, Xu N, Liu Q, Li Y, Liu Y, Wong H, Burt ME, Jossy SV, Han J, He Y. Therapeutic Strategies Against Metabolic Imbalance in a Male Mouse Model With 5-HT2CR Loss-of-Function. Endocrinology 2024; 165:bqae063. [PMID: 38815086 DOI: 10.1210/endocr/bqae063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/07/2024] [Accepted: 05/28/2024] [Indexed: 06/01/2024]
Abstract
The serotonin 2C receptor (5-HT2CR)-melanocortin pathway plays well-established roles in the regulation of feeding behavior and body weight homeostasis. Dysfunctions in this system, such as loss-of-function mutations in the Htr2c gene, can lead to hyperphagia and obesity. In this study, we aimed to investigate the potential therapeutic strategies for ameliorating hyperphagia, hyperglycemia, and obesity associated with a loss-of-function mutation in the Htr2c gene (Htr2cF327L/Y). We demonstrated that reexpressing functional 5-HT2CR solely in hypothalamic pro-opiomelanocortin (POMC) neurons is sufficient to reduce food intake and body weight in Htr2cF327L/Y mice subjected to a high-fat diet (HFD). In addition, 5-HT2CR expression restores the responsiveness of POMC neurons to lorcaserin, a selective agonist for 5-HT2CR. Similarly, administration of melanotan II, an agonist of the melanocortin receptor 4 (MC4R), effectively suppresses feeding and weight gain in Htr2cF327L/Y mice. Strikingly, promoting wheel-running activity in Htr2cF327L/Y mice results in a decrease in HFD consumption and improved glucose homeostasis. Together, our findings underscore the crucial role of the melanocortin system in alleviating hyperphagia and obesity related to dysfunctions of the 5-HT2CR, and further suggest that MC4R agonists and lifestyle interventions might hold promise in counteracting hyperphagia, hyperglycemia, and obesity in individuals carrying rare variants of the Htr2c gene.
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MESH Headings
- Animals
- Receptor, Serotonin, 5-HT2C/metabolism
- Receptor, Serotonin, 5-HT2C/genetics
- Male
- Mice
- Hyperphagia/metabolism
- Hyperphagia/genetics
- Pro-Opiomelanocortin/metabolism
- Pro-Opiomelanocortin/genetics
- Diet, High-Fat
- Obesity/metabolism
- Obesity/genetics
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- Receptor, Melanocortin, Type 4/agonists
- alpha-MSH/pharmacology
- alpha-MSH/analogs & derivatives
- Loss of Function Mutation
- Hypothalamus/metabolism
- Body Weight/drug effects
- Eating/drug effects
- Eating/physiology
- Eating/genetics
- Neurons/metabolism
- Neurons/drug effects
- Disease Models, Animal
- Hyperglycemia/metabolism
- Hyperglycemia/genetics
- Mice, Inbred C57BL
- Benzazepines
- Peptides, Cyclic
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Affiliation(s)
- Hailan Liu
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhaoxun Liu
- Nursing Department, The Third Xiangya Hospital, Central South University, Changsha, Hunan, 410013, China
- Department of Emergency, The Third Xiangya Hospital, Central South University, Changsha, Hunan, 410013, China
| | - HueyXian Kelly Wong
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Nathan Xu
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Qingzhuo Liu
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yongxiang Li
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yao Liu
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - HueyZhong Wong
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Megan E Burt
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sanika V Jossy
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Junying Han
- USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yang He
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Department of Pediatrics, Section of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
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5
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Kang H, Kim J, Park CH, Jeong B, So I. Direct modulation of TRPC ion channels by Gα proteins. Front Physiol 2024; 15:1362987. [PMID: 38384797 PMCID: PMC10880550 DOI: 10.3389/fphys.2024.1362987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 01/26/2024] [Indexed: 02/23/2024] Open
Abstract
GPCR-Gi protein pathways are involved in the regulation of vagus muscarinic pathway under physiological conditions and are closely associated with the regulation of internal visceral organs. The muscarinic receptor-operated cationic channel is important in GPCR-Gi protein signal transduction as it decreases heart rate and increases GI rhythm frequency. In the SA node of the heart, acetylcholine binds to the M2 receptor and the released Gβγ activates GIRK (I(K,ACh)) channel, inducing a negative chronotropic action. In gastric smooth muscle, there are two muscarinic acetylcholine receptor (mAChR) subtypes, M2 and M3. M2 receptor activates the muscarinic receptor-operated nonselective cationic current (mIcat, NSCC(ACh)) and induces positive chronotropic effect. Meanwhile, M3 receptor induces hydrolysis of PIP2 and releases DAG and IP3. This IP3 increases intracellular Ca2+ and then leads to contraction of GI smooth muscles. The activation of mIcat is inhibited by anti-Gi/o protein antibodies in GI smooth muscle, indicating the involvement of Gαi/o protein in the activation of mIcat. TRPC4 channel is a molecular candidate for mIcat and can be directly activated by constitutively active Gαi QL proteins. TRPC4 and TRPC5 belong to the same subfamily and both are activated by Gi/o proteins. Initial studies suggested that the binding sites for G protein exist at the rib helix or the CIRB domain of TRPC4/5 channels. However, recent cryo-EM structure showed that IYY58-60 amino acids at ARD of TRPC5 binds with Gi3 protein. Considering the expression of TRPC4/5 in the brain, the direct G protein activation on TRPC4/5 is important in terms of neurophysiology. TRPC4/5 channels are also suggested as a coincidence detector for Gi and Gq pathway as Gq pathway increases intracellular Ca2+ and the increased Ca2+ facilitates the activation of TRPC4/5 channels. More complicated situation would occur when GIRK, KCNQ2/3 (IM) and TRPC4/5 channels are co-activated by stimulation of muscarinic receptors at the acetylcholine-releasing nerve terminals. This review highlights the effects of GPCR-Gi protein pathway, including dopamine, μ-opioid, serotonin, glutamate, GABA, on various oragns, and it emphasizes the importance of considering TRPC4/5 channels as crucial players in the field of neuroscience.
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Affiliation(s)
- Hana Kang
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jinhyeong Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Christine Haewon Park
- Department of Physiology, University of California, San Francisco, San Francisco, CA, United States
| | - Byeongseok Jeong
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Insuk So
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
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6
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Shin Y, Kim S, Sohn JW. Serotonergic regulation of appetite and sodium appetite. J Neuroendocrinol 2023; 35:e13328. [PMID: 37525500 DOI: 10.1111/jne.13328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 06/27/2023] [Accepted: 07/15/2023] [Indexed: 08/02/2023]
Abstract
Serotonin is a neurotransmitter that is synthesized and released from the brainstem raphe nuclei to affect many brain functions. It is well known that the activity of raphe serotonergic neurons is changed in response to the changes in feeding status to regulate appetite via the serotonin receptors. Likewise, changes in volume status are known to alter the activity of raphe serotonergic neurons and drugs targeting serotonin receptors were shown to affect sodium appetite. Therefore, the central serotonin system appears to regulate ingestion of both food and salt, although neural mechanisms that induce appetite in response to hunger and sodium appetite in response to volume depletion are largely distinct from each other. In this review, we discuss our current knowledge regarding the regulation of ingestion - appetite and sodium appetite - by the central serotonin system.
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Affiliation(s)
- Yurim Shin
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Seungjik Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Jong-Woo Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
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7
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Sun Q, van de Lisdonk D, Ferrer M, Gegenhuber B, Wu M, Tollkuhn J, Janowitz T, Li B. Area postrema neurons mediate interleukin-6 function in cancer-associated cachexia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.12.523716. [PMID: 36711916 PMCID: PMC9882141 DOI: 10.1101/2023.01.12.523716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Interleukin-6 (IL-6) has been long considered a key player in cancer-associated cachexia 1-15 . It is believed that sustained elevation of IL-6 production during cancer progression causes brain dysfunctions, which ultimately result in cachexia 16-20 . However, how peripheral IL-6 influences the brain remains poorly understood. Here we show that neurons in the area postrema (AP), a circumventricular structure in the hindbrain, mediate the function of IL-6 in cancer-associated cachexia in mice. We found that circulating IL-6 can rapidly enter the AP and activate AP neurons. Peripheral tumor, known to increase circulating IL-6 1-5,15,18,21-23 , leads to elevated IL-6 and neuronal hyperactivity in the AP, and causes potentiated excitatory synaptic transmission onto AP neurons. Remarkably, neutralization of IL-6 in the brain of tumor-bearing mice with an IL-6 antibody prevents cachexia, reduces the hyperactivity in an AP network, and markedly prolongs lifespan. Furthermore, suppression of Il6ra , the gene encoding IL-6 receptor, specifically in AP neurons with CRISPR/dCas9 interference achieves similar effects. Silencing of Gfral-expressing AP neurons also ameliorates the cancer-associated cachectic phenotypes and AP network hyperactivity. Our study identifies a central mechanism underlying the function of peripheral IL-6, which may serve as a target for treating cancer-associated cachexia.
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8
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Raphe serotonin projections dynamically regulate feeding behavior through targeting inhibitory circuits from rostral zona incerta to paraventricular thalamus. Mol Metab 2022; 66:101634. [PMID: 36351530 PMCID: PMC9672487 DOI: 10.1016/j.molmet.2022.101634] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE Rostral zona incerta (ZIR) evokes feeding by sending GABA transmission to paraventricular thalamus (PVT). Although central serotonin (5-HT) signaling is known to play critical roles in the regulation of food intake and eating disorders, it remains unknown whether raphe 5-HT neurons functionally innervate ZIR-PVT neural pathway for feeding control. Here, we sought to reveal how raphe 5-HT signaling regulates both ZIR and PVT for feeding control. METHODS We used retrograde neural tracers to map 5-HT projections in Sert-Cre mice and slice electrophysiology to examine the mechanism by which 5-HT modulates ZIR GABA neurons. We also used optogenetics to test the effects of raphe-ZIR and raphe-PVT 5-HT projections on feeding motivation and food intake in mice regularly fed, 24 h fasted, and with intermittent high-fat high-sugar (HFHS) diet. In addition, we applied RNAscope in situ hybridization to identify 5-HT receptor subtype mRNA in ZIR. RESULTS We show raphe 5-HT neurons sent projections to both ZIR and PVT with partial collateral axons. Photostimulation of 5-HT projections inhibited ZIR but excited PVT neurons to decrease motivated food consumption. However, both acute food deprivation and intermittent HFHS diet downregulated 5-HT inhibition on ZIR GABA neurons, abolishing the inhibitory regulation of raphe-ZIR 5-HT projections on feeding motivation and food intake. Furthermore, we found high-level 5-HT1a and 5-HT2c as well as low-level 5-HT7 mRNA expression in ZIR. Intermittent HFHS diet increased 5-HT7 but not 5-HT1a or 5-HT2c mRNA levels in the ZIR. CONCLUSIONS Our results reveal that raphe-ZIR 5-HT projections dynamically regulate ZIR GABA neurons for feeding control, supporting that a dynamic fluctuation of ZIR 5-HT inhibition authorizes daily food intake but a sustained change of ZIR 5-HT signaling leads to overeating induced by HFHS diet.
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9
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Li L, Wyler SC, León-Mercado LA, Xu B, Oh Y, Swati, Chen X, Wan R, Arnold AG, Jia L, Wang G, Nautiyal K, Hen R, Sohn JW, Liu C. Delineating a serotonin 1B receptor circuit for appetite suppression in mice. J Exp Med 2022; 219:213337. [PMID: 35796804 PMCID: PMC9270184 DOI: 10.1084/jem.20212307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 04/04/2022] [Accepted: 06/13/2022] [Indexed: 01/09/2023] Open
Abstract
Triptans are a class of commonly prescribed antimigraine drugs. Here, we report a previously unrecognized role for them to suppress appetite in mice. In particular, frovatriptan treatment reduces food intake and body weight in diet-induced obese mice. Moreover, the anorectic effect depends on the serotonin (5-HT) 1B receptor (Htr1b). By ablating Htr1b in four different brain regions, we demonstrate that Htr1b engages in spatiotemporally segregated neural pathways to regulate postnatal growth and food intake. Moreover, Htr1b in AgRP neurons in the arcuate nucleus of the hypothalamus (ARH) contributes to the hypophagic effects of HTR1B agonists. To further study the anorexigenic Htr1b circuit, we generated Htr1b-Cre mice. We find that ARH Htr1b neurons bidirectionally regulate food intake in vivo. Furthermore, single-nucleus RNA sequencing analyses revealed that Htr1b marks a subset of AgRP neurons. Finally, we used an intersectional approach to specifically target these neurons (Htr1bAgRP neurons). We show that they regulate food intake, in part, through a Htr1bAgRP→PVH circuit.
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Affiliation(s)
- Li Li
- The Hypothalamic Research Center, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Steven C. Wyler
- The Hypothalamic Research Center, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Luis A. León-Mercado
- The Hypothalamic Research Center, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Baijie Xu
- The Hypothalamic Research Center, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Youjin Oh
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Swati
- The Hypothalamic Research Center, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Xiameng Chen
- The Hypothalamic Research Center, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Rong Wan
- The Hypothalamic Research Center, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Amanda G. Arnold
- The Hypothalamic Research Center, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Lin Jia
- Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX
| | - Guanlin Wang
- Centre for Computational Biology, Medical Research Council Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Katherine Nautiyal
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH
| | - René Hen
- Department of Psychiatry, Columbia University and Research Foundation for Mental Hygiene, New York State Psychiatric Institute, New York, NY,Department of Neuroscience, Columbia University, New York, NY,Department of Pharmacology, Columbia University, New York, NY
| | - Jong-Woo Sohn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Korea,Jong-Woo Sohn:
| | - Chen Liu
- The Hypothalamic Research Center, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX,Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX,Peter O’Donnell Jr. Brain Institute, UT Southwestern Medical Center, Dallas, TX,Correspondence to Chen Liu:
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