MCH-R1 Antagonist GPS18169, a Pseudopeptide, Is a Peripheral Anti-Obesity Agent in Mice

Melanin-concentrating hormone (MCH) is a 19 amino acid long peptide found in the brain of animals, including fishes, batrachians, and mammals. MCH is implicated in appetite and/or energy homeostasis. Antagonists at its receptor (MCH-R1) could be major tools (or ultimately drugs) to understand the mechanism of MCH action and to fight the obesity syndrome that is a worldwide societal health problem. Ever since the deorphanisation of the MCH receptor, we cloned, expressed, and characterized the receptor MCH-R1 and started a vast medicinal chemistry program aiming at the discovery of such usable compounds. In the present final work, we describe GPS18169, a pseudopeptide antagonist at the MCH-R1 receptor with an affinity in the nanomolar range and a Ki for its antagonistic effect in the 20 picomolar range. Its metabolic stability is rather ameliorated compared to its initial parent compound, the antagonist S38151. We tested it in an in vivo experiment using high diet mice. GPS18169 was found to be active in limiting the accumulation of adipose tissues and, correlatively, we observed a normalization of the insulin level in the treated animals, while no change in food or water consumption was observed.

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Efficacy of Guanabenz Combination Therapy against Chronic Toxoplasmosis across Multiple Mouse Strains

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00539-20 ◽

2020 ◽

Vol 64 (9) ◽

Cited By ~ 1

Author(s):

Jennifer Martynowicz ◽

J. Stone Doggett ◽

William J. Sullivan

Keyword(s):

Limit Of Detection ◽

Acute Infection ◽

Antagonistic Effect ◽

Mouse Strains ◽

Chronic Infections ◽

Content Type ◽

Brain Cyst ◽

The Brain

ABSTRACT Toxoplasma gondii, an obligate intracellular parasite that can cause life-threatening acute disease, differentiates into a quiescent cyst stage to establish lifelong chronic infections in animal hosts, including humans. This tissue cyst reservoir, which can reactivate into an acute infection, is currently refractory to clinically available therapeutics. Recently, we and others have discovered drugs capable of significantly reducing the brain cyst burden in latently infected mice, but not to undetectable levels. In this study, we examined the use of novel combination therapies possessing multiple mechanisms of action in mouse models of latent toxoplasmosis. Our drug regimens included combinations of pyrimethamine, clindamycin, guanabenz, and endochin-like quinolones (ELQs) and were administered to two different mouse strains in an attempt to eradicate brain tissue cysts. We observed mouse strain-dependent effects with these drug treatments: pyrimethamine-guanabenz showed synergistic efficacy in C57BL/6 mice yet did not improve upon guanabenz monotherapy in BALB/c mice. Contrary to promising in vitro results demonstrating toxicity to bradyzoites, we observed an antagonistic effect between guanabenz and ELQ-334 in vivo. While we were unable to completely eliminate the brain cyst burden, we found that a combination treatment with ELQ-334 and pyrimethamine impressively reduced the brain cyst burden by 95% in C57BL/6 mice, which approached the limit of detection. These analyses highlight the importance of evaluating anti-infective drugs in multiple mouse strains and will help inform further preclinical studies of cocktail therapies designed to treat chronic toxoplasmosis.

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Sensitive enzyme electrodes

Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences ◽

10.1098/rsta.1990.0136 ◽

1990 ◽

Vol 333 (1628) ◽

pp. 49-61 ◽

Cited By ~ 3

Keyword(s):

Packed Bed ◽

Current Time ◽

Enzyme Electrodes ◽

Freely Moving ◽

The Brain ◽

Nanomolar Range ◽

Inhibited Enzyme ◽

Micromolar Range

Conventional enzyme electrodes are relatively insensitive devices capable of measuring analytes in the micromolar range. Inhibited enzyme electrodes work by measuring the inhibition of an enzyme turning over undersaturated conditions. This increased turnover gives greater sensitivity. The detection limits are controlled either by the thermodynamic amplitude or by the kinetic discrimination. Software has been developed to analyse the current time transient to produce concentrations of the inhibitor. Results for CN- and H 2 S are presented. The packed bed wall jet electrode is an electrode assembly that allows complete reaction of the substrate with the enzyme coupled to an efficient hydrodynamic régime for electrochemical detection. Results for the determination of acetylcholine are presented. The electrode can also be used in an immunoassay for the determination of human immunoglobulin in the nanomolar range. Finally results will be presented for in vivo changes in ascorbate in the brain of the freely moving rat as a result of tail pinch; changes on a timescale of half a second can be followed.

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Determination of the Interaction and Pharmacological Modulation of MCHR1 Signaling by C Terminus of MRAP2 Protein

10.21203/rs.3.rs-829492/v1 ◽

2021 ◽

Author(s):

Meng Wang ◽

Yue Zhai ◽

Xiaowei Lei ◽

Jing Xu ◽

Bopei Jiang ◽

...

Keyword(s):

Energy Homeostasis ◽

Transmembrane Protein ◽

Melanocortin Receptor ◽

Pharmacological Modulation ◽

C Terminus ◽

Melanin Concentrating Hormone ◽

The Central Nervous System

Abstract Background: Melanin concentrating hormone (MCH), an orexigenic neuropeptide, is primarily secreted by the hypothalamus and acts at its receptor, the melanin-concentrating hormone receptor 1 (MCHR1), to regulate energy homeostasis and body weight. The Melanocortin Receptor Accessory Protein 2 (MRAP2), a small single transmembrane protein broadly expressed in multiple tissues, has been defined as a vital endocrine pivot of five melanocortin receptors (MC1R-MC5R) and several other GPCRs in the regulation of central neuronal appetite and peripheral energy homeostasis. However, the regulatory and relationship between MCHR1 and MRAP2 is unknown.Results: In this study, we show that MRAP2 interacts with MCHR1 and suppresses MCHR1 signaling in vitro. We also identified the C-terminal domains of MRAP2 protein required for pharmacological modulation of intracellular Ca2+ cascades and membrane transport.Conclusions: These findings elucidated the broad regulatory profile of MRAP2 protein in the central nervous system and may provide implications for the modulation of central MCHR1 function in vivo.

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Dual orexin and MCH neuron-ablated mice display severe sleep attacks and cataplexy

eLife ◽

10.7554/elife.54275 ◽

2020 ◽

Vol 9 ◽

Cited By ~ 2

Author(s):

Chi Jung Hung ◽

Daisuke Ono ◽

Thomas S Kilduff ◽

Akihiro Yamanaka

Keyword(s):

Transgenic Mice ◽

Spectral Power ◽

Nrem Sleep ◽

Functional Interaction ◽

Neuronal Populations ◽

Orexin Neuron ◽

Melanin Concentrating Hormone ◽

The Brain ◽

Theta Range

Orexin/hypocretin-producing and melanin-concentrating hormone-producing (MCH) neurons are co-extensive in the hypothalamus and project throughout the brain to regulate sleep/wakefulness. Ablation of orexin neurons decreases wakefulness and results in a narcolepsy-like phenotype, whereas ablation of MCH neurons increases wakefulness. Since it is unclear how orexin and MCH neurons interact to regulate sleep/wakefulness, we generated transgenic mice in which both orexin and MCH neurons could be ablated. Double-ablated mice exhibited increased wakefulness and decreased both rapid eye movement (REM) and non-REM (NREM) sleep. Double-ablated mice showed severe cataplexy compared with orexin neuron-ablated mice, suggesting that MCH neurons normally suppress cataplexy. Double-ablated mice also showed frequent sleep attacks with elevated spectral power in the delta and theta range, a unique state that we call ‘delta-theta sleep’. Together, these results indicate a functional interaction between orexin and MCH neurons in vivo that suggests the synergistic involvement of these neuronal populations in the sleep/wakefulness cycle.

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Obesity remodels activity and transcriptional state of a lateral hypothalamic brake on feeding

Science ◽

10.1126/science.aax1184 ◽

2019 ◽

Vol 364 (6447) ◽

pp. 1271-1274 ◽

Cited By ~ 26

Author(s):

Mark A. Rossi ◽

Marcus L. Basiri ◽

Jenna A. McHenry ◽

Oksana Kosyk ◽

James M. Otis ◽

...

Keyword(s):

Energy Homeostasis ◽

Health Concern ◽

Hypothalamic Area ◽

Obesity Epidemic ◽

Glutamatergic Neurons ◽

Two Photon ◽

Lateral Hypothalamic ◽

The Brain ◽

Transcriptional State

The current obesity epidemic is a major worldwide health concern. Despite the consensus that the brain regulates energy homeostasis, the neural adaptations governing obesity are unknown. Using a combination of high-throughput single-cell RNA sequencing and longitudinal in vivo two-photon calcium imaging, we surveyed functional alterations of the lateral hypothalamic area (LHA)—a highly conserved brain region that orchestrates feeding—in a mouse model of obesity. The transcriptional profile of LHA glutamatergic neurons was affected by obesity, exhibiting changes indicative of altered neuronal activity. Encoding properties of individual LHA glutamatergic neurons were then tracked throughout obesity, revealing greatly attenuated reward responses. These data demonstrate how diet disrupts the function of an endogenous feeding suppression system to promote overeating and obesity.

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Absence of neurotoxicity and lack of neurobehavioral consequences due to exposure to tetrabromobisphenol A (TBBPA) exposure in humans, animals and zebrafish

Archives of Toxicology ◽

10.1007/s00204-019-02627-y ◽

2019 ◽

Vol 94 (1) ◽

pp. 59-66 ◽

Cited By ~ 5

Author(s):

Sam Kacew ◽

A. Wallace Hayes

Keyword(s):

Flame Retardant ◽

Parent Compound ◽

Consumer Products ◽

The Body ◽

Tetrabromobisphenol A ◽

Human Breast Milk ◽

Target Tissue ◽

Brominated Flame Retardant ◽

The Brain

AbstractTetrabromobisphenol A (2,2′,6,6′-tetrabromo-4,4′-isopropylidenediphenol, CAS no. 79-94-7) (TBBPA) is an effective brominated flame retardant present in many consumer products whose effectiveness is attributable to its ability to retard flames and consequently save human lives. Toxicokinetic studies revealed that TBBPA when absorbed via the gastrointestinal tract is rapidly metabolized to glucuronide or sulfate metabolites which are rapidly eliminated by the kidney. TBBPA does not accumulate in the body and there is no evidence that the parent compound is present in the brain. Although this brominated flame retardant was detected in human breast milk and serum, there was no evidence that TBBPA reached the brain in in vivo animal studies as reflected by the absence of neuropathological, neurotoxic, or behavioral alterations indicating that the central nervous system is not a target tissue. These animal investigations were further supported by use of the larval/embryo observations that TBBPA did not produce behavioral changes in a larval/embryo zebrafish a model of chemical-induced neurotoxicity. Although some protein expressions were increased, deceased or not affected in the blood–brain barrier indicating no evidence that TBBPA entered the brain, the changes were contradictory, or gender related, and behavior was not affected supporting that this compound was not neurotoxic. Taken together, TBBPA does not appear to target the brain and is not considered as a neurotoxicant.

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Dual Orexin and MCH neuron-ablated mice display severe sleep attacks and cataplexy

10.1101/2019.12.17.880229 ◽

2019 ◽

Author(s):

Chi Jung Hung ◽

Daisuke Ono ◽

Thomas S. Kilduff ◽

Akihiro Yamanaka

Keyword(s):

Spectral Power ◽

Nrem Sleep ◽

Functional Interaction ◽

Neuronal Populations ◽

Orexin Neuron ◽

Melanin Concentrating Hormone ◽

The Mean ◽

The Brain ◽

Theta Range

SummaryOrexin/hypocretin-producing and melanin-concentrating hormone-producing (MCH) neurons are co-extensive in the tuberal hypothalamus and project throughout the brain to regulate sleep/wakefulness. Ablation of orexin neurons in mice decreases wakefulness and results in a narcolepsy-like phenotype, whereas ablation of MCH neurons increases wakefulness. Since it is unclear how orexin and MCH neurons interact to regulate sleep/wakefulness, we generated conditional transgenic mice in which both orexin and MCH neurons could be ablated. Double-ablated mice exhibited increased wakefulness and decreased both rapid eye movement (REM) and non-REM (NREM) sleep. The total time in cataplexy and the mean cataplexy bout duration increased significantly in double-ablated mice compared with orexin neuron-ablated mice, suggesting that MCH neurons normally suppress cataplexy and that compromised MCH neurons may exacerbate symptoms in some narcoleptic patients. Double-ablated mice also showed frequent sleep attacks with elevated spectral power in the delta and theta range during wakefulness, a state with EEG characteristics indistinguishable from the transition from NREM into REM sleep. Together, these results indicate a functional interaction between orexin and MCH neurons in vivo that suggests the synergistic involvement of these neuronal populations in the sleep/wakefulness cycle.

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Viral Infection Drives the Regulation of Feeding Behavior Related Genes in Salmo salar

International Journal of Molecular Sciences ◽

10.3390/ijms222111391 ◽

2021 ◽

Vol 22 (21) ◽

pp. 11391

Author(s):

David Muñoz ◽

Ricardo Fuentes ◽

Beatriz Carnicero ◽

Andrea Aguilar ◽

Nataly Sanhueza ◽

...

Keyword(s):

Food Intake ◽

Viral Infection ◽

Feeding Behavior ◽

Energy Homeostasis ◽

Infectious Pancreatic Necrosis Virus ◽

Complex Activity ◽

Fish Remains ◽

Pancreatic Necrosis Virus ◽

The Brain

The feeding behavior in fish is a complex activity that relies on the ability of the brain to integrate multiple signals to produce appropriate responses in terms of food intake, energy expenditure, and metabolic activity. Upon stress cues including viral infection or mediators such as the proinflammatory cytokines, prostaglandins, and cortisol, both Pomc and Npy/Agrp neurons from the hypothalamus are stimulated, thus triggering a response that controls both energy storage and expenditure. However, how appetite modulators or neuro-immune cues link pathogenesis and energy homeostasis in fish remains poorly understood. Here, we provide the first evidence of a molecular linkage between inflammation and food intake in Salmon salar. We show that in vivo viral challenge with infectious pancreatic necrosis virus (IPNV) impacts food consumption by activating anorexic genes such as mc4r, crf, and pomcb and 5-HT in the brain of S. salar. At the molecular level, viral infection induces an overall reduction in lipid content in the liver, favoring the production of AA and EPA associated with the increment of elovl2 gene. In addition, infection upregulates leptin signaling and inhibits insulin signaling. These changes are accompanied by a robust inflammatory response represented by the increment of Il-1b, Il-6, Tnfa, and Pge2 as well as an increased cortisol level in vivo. Thus, we propose a model in which hypothalamic neurons respond to inflammatory cytokines and stress-related molecules and interact with appetite induction/inhibition. These findings provide evidence of crosstalk between pathogenesis-driven inflammation and hypothalamic–pituitary–adrenocortical axes in stress-induced food intake behavior in fish.

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Determination of the Interaction and Pharmacological Modulation of MCHR1 Signaling by C Terminus of MRAP2 Protein

10.21203/rs.3.rs-829492/v2 ◽

2021 ◽

Author(s):

Meng Wang ◽

Yue Zhai ◽

Xiaowei Lei ◽

Jing Xu ◽

Bopei Jiang ◽

...

Keyword(s):

Energy Homeostasis ◽

Transmembrane Protein ◽

Melanocortin Receptor ◽

Pharmacological Modulation ◽

C Terminus ◽

Melanin Concentrating Hormone ◽

The Central Nervous System

Abstract Background: Melanin concentrating hormone (MCH), an orexigenic neuropeptide, is primarily secreted by the hypothalamus and acts at its receptor, the melanin-concentrating hormone receptor 1 (MCHR1), to regulate energy homeostasis and body weight. The Melanocortin Receptor Accessory Protein 2 (MRAP2), a small single transmembrane protein broadly expressed in multiple tissues, has been defined as a vital endocrine pivot of five melanocortin receptors (MC1R-MC5R) and several other GPCRs in the regulation of central neuronal appetite and peripheral energy homeostasis. However, the regulatory and relationship between MCHR1 and MRAP2 is unknown.Results: In this study, we show that MRAP2 interacts with MCHR1 and suppresses MCHR1 signaling in vitro. We also identified the C-terminal domains of MRAP2 protein required for pharmacological modulation of intracellular Ca2+ cascades and membrane transport. Conclusions: These findings elucidated the broad regulatory profile of MRAP2 protein in the central nervous system and may provide implications for the modulation of central MCHR1 function in vivo.

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Regulation of Brain Primary Cilia Length by MCH Signaling: Evidence from Pharmacological, Genetic, Optogenetic and Chemogenic Manipulations

10.1101/2021.04.07.438846 ◽

2021 ◽

Author(s):

Wedad Alhassen ◽

Yuki Kobayashi ◽

Jessica Su ◽

Brianna Robbins ◽

Henry Ngyuen ◽

...

Keyword(s):

Energy Homeostasis ◽

Primary Cilia ◽

Designer Drugs ◽

Genetic Manipulations ◽

Pathological Conditions ◽

Melanin Concentrating Hormone ◽

Agonist And Antagonist ◽

And Migration ◽

External Stimuli

AbstractThe melanin concentrating hormone (MCH) system is involved in numerous functions including energy homeostasis, food intake, sleep, stress, mood, aggression, reward, maternal behavior, social behavior, and cognition. MCH acts on a G protein-coupled receptor MCHR1, which expresses ubiquitously in the brain and localizes to neuronal primary cilia. Cilia act as cells’ antennas and play crucial roles in cell signaling to detect and transduce external stimuli to regulate cell differentiation and migration. Cilia are highly dynamic in terms of their length and morphology; however, it is not known if cilia length is causally regulated by MCH system activation in-vivo. In the current work, we examined the effects of the activation and inactivation of MCH system on cilia lengths by using different methodologies, including pharmacological (MCHR1 agonist and antagonist GW803430), germline and conditional genetic deletion of MCHR1 and MCH, optogenetic, and chemogenetic (Designer Receptors Exclusively Activated by Designer Drugs (DREADD)) approaches. We found that stimulation of MCH system either directly through MCHR1 activation, or indirectly through optogenetic and chemogenetic- mediated excitation of MCH neurons, causes cilia shortening. Contrarily, inactivation of MCH signaling through pharmacological MCHR1 blockade or through genetic manipulations - germline deletion of MCHR1 and conditional ablation of MCH neurons - induces cilia lengthening. Our study is the first to uncover the causal effects of the MCH system in the regulation of the length of brain neuronal primary cilia. These findings place MCH system at a unique position in the ciliary signaling in physiological and pathological conditions, and implicate cilia MCHR1 as a potential therapeutic target for the treatment of pathological conditions characterized by impaired cilia function.

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