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Axiak‐Bechtel SM, Leach SB, Newton‐Northup JR, Milner RJ, Fox‐Alvarez SA, Fagman LI, Young KA, Tate DJ, Wright ZM, Chretin JD, Allen JW, Yoshimoto SK, Selting KA, Flesner BK, White CR, Mills T, Aherne M, Bergman PJ, Qi L, Gruber KA, Callahan MF. Safety of TCMCB07, a melanocortin-4 antagonist peptide, in dogs with naturally occurring cachexia. J Vet Intern Med 2023; 37:2344-2355. [PMID: 37897303 PMCID: PMC10658582 DOI: 10.1111/jvim.16915] [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: 05/30/2023] [Accepted: 10/13/2023] [Indexed: 10/30/2023] Open
Abstract
BACKGROUND The melanocortin 4 antagonist TCMCB07 is safe and effective in reversing cachexia caused by sepsis or cancer in rodents. The safety and pharmacokinetics of TCMCB07 are demonstrated in healthy beagle dogs. HYPOTHESIS/OBJECTIVES The objectives of this study were to investigate the safety, peak plasma concentrations, and potential for efficacy of TCMCB07 in pet dogs with naturally occurring cachexia over a 4-week time period. ANIMALS Fourteen dogs with cachexia of any underlying cause, except cancer of the oral cavity or gastrointestinal tract, were eligible for enrollment with informed client consent. METHODS This study was a prospective, 1-armed open-label trial. Physical examination, complete blood count, chemistry panel, and owner-assessed quality of life surveys were checked at weeks 1, 2, and 4. Due to potential for bradycardia and hypotension, Holter monitoring and blood pressure evaluations were scheduled at pre-enrollment and week 4. RESULTS Fourteen dogs completed the trial. Significant changes detected included increased mean body weight (18.6-19.5 kg, P < .02), increased body condition score (median Tufts 5-point thin dog scale score P < .004 and WSAVA muscle condition score P < .02) and increased mean blood urea nitrogen (21.79-30.43 mg dL-1 , P < .004). On quality of life surveys, pet owners perceived their dog appeared to be panting less (P < .002) and that the general health improved (P < .03). Four dogs had a change in coat pigmentation. The peak plasma concentration of TCMCB07 in cachectic dogs was similar to that in healthy beagle dogs. CONCLUSIONS AND CLINICAL IMPORTANCE TCMCB07 was safe and has potential efficacy in pet dogs with cachexia.
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Affiliation(s)
| | - Stacey B. Leach
- Department of Veterinary Medicine and SurgeryUniversity of MissouriColumbiaMissouriUSA
| | | | - Rowan J. Milner
- Department of Small Animal Clinical SciencesUniversity of FloridaGainesvilleFloridaUSA
| | - Stacey A. Fox‐Alvarez
- Department of Small Animal Clinical SciencesUniversity of FloridaGainesvilleFloridaUSA
| | - Lana I. Fagman
- Department of Small Animal Clinical SciencesUniversity of FloridaGainesvilleFloridaUSA
| | - Kaylee A. Young
- Department of Small Animal Clinical SciencesUniversity of FloridaGainesvilleFloridaUSA
| | - Deborah J. Tate
- Department of Veterinary Medicine and SurgeryUniversity of MissouriColumbiaMissouriUSA
| | | | - John D. Chretin
- VCA West Los AngelesLos AngelesCaliforniaUSA
- Present address:
VCA Veterinary Specialists of the ValleyWoodland HillsCaliforniaUSA
| | | | - Sean K. Yoshimoto
- VCA West Los AngelesLos AngelesCaliforniaUSA
- Present address:
VCA Animal Specialty and Emergency CenterLos AngelesCaliforniaUSA
| | - Kimberly A. Selting
- Department of Veterinary Medicine and SurgeryUniversity of MissouriColumbiaMissouriUSA
- Present address:
Department of Veterinary Clinical Medicine, College of Veterinary MedicineUniversity of Illinois Urbana‐ChampaignUrbanaIllinoisUSA
| | - Brian K. Flesner
- Department of Veterinary Medicine and SurgeryUniversity of MissouriColumbiaMissouriUSA
- Present address:
Department of Clinical Sciences and Advanced Medicine, School of Veterinary MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Carrie R. White
- VCA Family and Oahu Veterinary Specialty CenterPearl CityHawaiiUSA
| | - Tracy Mills
- VCA Clinical StudiesLos AngelesCaliforniaUSA
| | - Michael Aherne
- Department of Small Animal Clinical SciencesUniversity of FloridaGainesvilleFloridaUSA
| | | | - LeAnn Qi
- TCI Peptide TherapeuticsColumbiaMissouriUSA
| | - Kenneth A. Gruber
- TCI Peptide TherapeuticsColumbiaMissouriUSA
- Department of Medical Pharmacology & Physiology and the Dalton Cardiovascular Research CenterUniversity of MissouriColumbiaMissouriUSA
| | - Michael F. Callahan
- Department of Medical Pharmacology & Physiology and the Dalton Cardiovascular Research CenterUniversity of MissouriColumbiaMissouriUSA
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Ji RL, Jiang SS, Tao YX. Modulation of Canine Melanocortin-3 and -4 Receptors by Melanocortin-2 Receptor Accessory Protein 1 and 2. Biomolecules 2022; 12:biom12111608. [PMID: 36358958 PMCID: PMC9687446 DOI: 10.3390/biom12111608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 10/26/2022] [Accepted: 10/29/2022] [Indexed: 11/06/2022] Open
Abstract
The neural melanocortin receptors (MCRs), melanocortin-3 and -4 receptors (MC3R and MC4R), have crucial roles in regulating energy homeostasis. The melanocortin-2 receptor accessory proteins (MRAPs, MRAP1 and MRAP2) have been shown to regulate neural MCRs in a species-specific manner. The potential effects of MRAP1 and MRAP2 on canine neural MCRs have not been investigated before. Herein, we cloned canine (c) MC3R and identified one canine MRAP2 splice variant, MRAP2b, with N-terminal extension of cMRAP2a. Canine MC3R showed higher maximal responses to five agonists than those of human MC3R. We further investigated the modulation of cMRAP1, cMRAP2a, and cMRAP2b, on cMC3R and cMC4R pharmacology. For the cMC3R, all MRAPs had no effect on trafficking; cMRAP1 significantly decreased Bmax whereas cMRAP2a and cMRAP2b significantly increased Bmax. Both MRAP1 and MRAP2a decreased Rmaxs in response to α-MSH and ACTH; MRAP2b only decreased α-MSH-stimulated cAMP generation. For the MC4R, MRAP1 and MRAP2a increased cell surface expression, and MRAP1 and MRAP2a increased Bmaxs. All MRAPs had increased affinities to α-MSH and ACTH. MRAP2a increased ACTH-induced cAMP levels, whereas MRAP2b decreased α-MSH- and ACTH-stimulated cAMP production. These findings may lead to a better understanding of the regulation of neural MCRs by MRAP1 and MRAP2s.
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Tao YX. Mutations in melanocortin-4 receptor: From fish to men. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 189:215-257. [PMID: 35595350 DOI: 10.1016/bs.pmbts.2022.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Melanocortin-4 receptor (MC4R), expressed abundantly in the hypothalamus, is a critical regulator of energy homeostasis, including both food intake and energy expenditure. Shortly after the publication in 1997 of the Mc4r knockout phenotypes in mice, including increased food intake and severe obesity, the first mutations in MC4R were reported in humans in 1998. Studies in the subsequent two decades have established MC4R mutation as the most common monogenic form of obesity, especially in early-onset severe obesity. Studies in animals, from fish to mammals, have established the conserved physiological roles of MC4R in all vertebrates in regulating energy balance. Drug targeting MC4R has been recently approved for treating morbid genetic obesity. How the MC4R can be exploited for animal production is highly worthy of active investigation.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, United States.
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Axiak‐Bechtel SM, Leach SB, Scholten DG, Newton‐Northup JR, Johnson BJ, Durham HE, Gruber KA, Callahan MF. Pharmacokinetics and safety of TCMCB07, a melanocortin-4 antagonist peptide in dogs. Pharmacol Res Perspect 2021; 9:e00777. [PMID: 34014033 PMCID: PMC8135083 DOI: 10.1002/prp2.777] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/08/2021] [Accepted: 03/15/2021] [Indexed: 12/12/2022] Open
Abstract
The melanocortin-4 receptor (MC4R) antagonistic peptide TCMCB07 was developed for the treatment of cachexia. The objectives of this study were to examine pharmacokinetics and safety of TCMCB07 administered subcutaneously to healthy dogs. Dogs were treated with high- (2.25 mg kg-1 ) (n = 5) and low-dose TCMCB07 (0.75 mg kg-1 ) (n = 5) once daily for 28 days with a 14-day washout period between groups. Histamine levels, complete blood count, chemistry panel, blood pressure, 24-hour Holter recording, and pharmacokinetic parameters were monitored in the high-dose group. Physical examination changes were limited to weight gain and darkening of the coat color. There was no elevation of plasma histamine within 24 hours of injection but there was a significant elevation of plasma histamine across time. An approximately doubled eosinophil count and an approximately 25% increase, and then 25% decrease back to pre-treatment plasma phosphorous were also found, although both remained within the reference interval. Serial blood pressure and 24-hour Holter monitors revealed no clinically relevant changes. A difference was found in the AUC between dosing groups and a significant effect of dose, time, and interaction was noted for Vd . Low-dose TCMCB07 had a Cmax of 2.1 ug ml-1 at day 28, compared to high-dose TCMCB07 which had a Cmax 3.6 ug ml-1 at day 28. Once-daily subcutaneous administration of TCMCB07 was well-tolerated for up to 28 days in dogs when administered at doses one and three times (0.75 mg kg-1 and 2.25 mg kg-1 ) the predicted therapeutic dose and pharmacokinetic parameters are described. SIGNIFICANCE STATEMENT: Melanocortin-4 receptor (MC4R) antagonistic peptide TCMCB07 is safe at both low and high doses in dogs. Therapy was tolerated well as determined by physical examination, clinical pathology, and cardiovascular parameters; darkening of the coat was noted with treatment and resolved with discontinuation. Pharmacokinetics are described and further study in the naturally occurring canine model is warranted.
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Affiliation(s)
- Sandra M. Axiak‐Bechtel
- Department of Veterinary Medicine and SurgeryUniversity of MissouriColumbiaMOUSA
- Present address:
Department of Small Animal Clinical SciencesUniversity of FloridaGainesvilleFLUSA
| | - Stacey B. Leach
- Department of Veterinary Medicine and SurgeryUniversity of MissouriColumbiaMOUSA
| | - David G. Scholten
- TCI Peptide TherapeuticsColumbiaMOUSA
- Present address:
Department of PharmacologyFainberg School of MedicineNorthwestern UniversityChicagoILUSA
| | | | - Brendan J. Johnson
- Department of Veterinary Medicine and SurgeryUniversity of MissouriColumbiaMOUSA
- TCI Peptide TherapeuticsColumbiaMOUSA
- Present address:
Wake Forest School of MedicineBowman Gray Center for Medical EducationWinston‐SalemNCUSA
| | - H. E. Durham
- Department of Veterinary Medicine and SurgeryUniversity of MissouriColumbiaMOUSA
- Present address:
Southwest Florida Veterinary SpecialistsBonita SpringsFLUSA
| | - Kenneth A. Gruber
- TCI Peptide TherapeuticsColumbiaMOUSA
- Department of Medical Pharmacology & Physiology and the Dalton Cardiovascular Research CenterUniversity of MissouriColumbiaMOUSA
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Wallis N, Raffan E. The Genetic Basis of Obesity and Related Metabolic Diseases in Humans and Companion Animals. Genes (Basel) 2020; 11:E1378. [PMID: 33233816 PMCID: PMC7699880 DOI: 10.3390/genes11111378] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 11/13/2020] [Accepted: 11/16/2020] [Indexed: 12/18/2022] Open
Abstract
Obesity is one of the most prevalent health conditions in humans and companion animals globally. It is associated with premature mortality, metabolic dysfunction, and multiple health conditions across species. Obesity is, therefore, of importance in the fields of medicine and veterinary medicine. The regulation of adiposity is a homeostatic process vulnerable to disruption by a multitude of genetic and environmental factors. It is well established that the heritability of obesity is high in humans and laboratory animals, with ample evidence that the same is true in companion animals. In this review, we provide an overview of how genes link to obesity in humans, drawing on a wealth of information from laboratory animal models, and summarise the mechanisms by which obesity causes related disease. Throughout, we focus on how large-scale human studies and niche investigations of rare mutations in severely affected patients have improved our understanding of obesity biology and can inform our ability to interpret results of animal studies. For dogs, cats, and horses, we compare the similarities in obesity pathophysiology to humans and review the genetic studies that have been previously reported in those species. Finally, we discuss how veterinary genetics may learn from humans about studying precise, nuanced phenotypes and implementing large-scale studies, but also how veterinary studies may be able to look past clinical findings to mechanistic ones and demonstrate translational benefits to human research.
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Affiliation(s)
- Natalie Wallis
- Anatomy Building, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Eleanor Raffan
- Anatomy Building, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
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6
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Melanocortin-4 receptor regulation of reproductive function in black rockfish (Sebastes schlegelii). Gene 2020; 741:144541. [PMID: 32165303 DOI: 10.1016/j.gene.2020.144541] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 02/20/2020] [Accepted: 03/08/2020] [Indexed: 01/15/2023]
Abstract
Melanocortin-4 receptor (MC4R) is a G protein-coupled receptor with multiple functions in mammals. However, the functions of MC4R in fish have not been investigated extensively. The purpose of this study was to determine potential regulation of reproduction by the MC4R. We cloned the black rockfish MC4R and analyzed its tissue distribution and function. The results showed that black rockfish mc4r cDNA consisted of 981 nucleotides encoding a protein of 326 amino acids. The quantitative PCR data showed that mc4r mRNA was primarily expressed in the brain, gonad, stomach and intestine. In the brain, mc4r was found to be primarily located in the hypothalamus. Both α-MSH and β-MSH increased gnih expression and decreased sgnrh and cgnrh expression (P < 0.05). α-MSH and β-MSH had opposite effects on kisspeptin expression. In contrast, α-MSH and β-MSH increased the expression of cyp11, cyp19, 3β-hsd and star. In summary, our study shows that MC4R in black rockfish might regulate reproductive function and that the effects of α-MSH and β-MSH might differ.
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Aono S, Dennis JC, He S, Wang W, Tao YX, Morrison EE. Exploring Pleiotropic Functions of Canine β-Defensin 103: Nasal Cavity Expression, Antimicrobial Activity, and Melanocortin Receptor Activity. Anat Rec (Hoboken) 2019; 304:210-221. [PMID: 31714028 DOI: 10.1002/ar.24300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 01/24/2023]
Abstract
Canine β-defensin 103 (cBD103) and its common variant cBD103ΔG23 are multitasking polypeptides. As a β-defensin, cBD103 is one of many antimicrobial agents used by the innate immunity to thwart pathogenic colonization. In this study, we showed that cBD103 was expressed throughout the nasal cavity, with primary expression in the nares as well as respiratory and olfactory epithelia. In the rostral nasal concha, cBD103 was expressed in the epithelium, and to a lesser degree in the lamina propria, but was absent in goblet cells. In the main olfactory epithelium, virtually all cells in the epithelial layer and select cells associated with Bowman's glands expressed cBD103. We also showed that the ΔG23 mutation did not appreciably alter the antimicrobial activity of the peptide against several species of microorganisms tested in nutrient-rich or minimal media or minimal media with salt added. Moreover, we showed antimicrobial activity in minimal media did not necessarily predict the inhibitory action of the peptide in nutrient-rich media. Both forms of cBD103 caused ultrastructural changes (membrane blebbing, condensation of intracellular contents and cell wall lysis) in Escherichia coli and Staphylococcus aureus. As a ligand of the melanocortin receptors, we showed that cBD103ΔG23 increased ERK1/2 activation and cAMP accumulation when bound to the human or canine melanocortin-4 receptor, acting as a weak allosteric agonist.
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Affiliation(s)
- Shelly Aono
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - John C Dennis
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Shan He
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Wei Wang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
| | - Edward E Morrison
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama
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8
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Polymorphism and methylation of the MC4R gene in obese and non-obese dogs. Mol Biol Rep 2017; 44:333-339. [PMID: 28755272 PMCID: PMC5579139 DOI: 10.1007/s11033-017-4114-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 07/19/2017] [Indexed: 11/26/2022]
Abstract
The dog is considered to be a useful biomedical model for human diseases and disorders, including obesity. One of the numerous genes associated with human polygenic obesity is MC4R, encoding the melanocortin 4 receptor. The aim of our study was to analyze polymorphisms and methylation of the canine MC4R in relation to adiposity. Altogether 270 dogs representing four breeds predisposed to obesity: Labrador Retriever (n = 187), Golden Retriever (n = 38), Beagle (n = 28) and Cocker Spaniel (n = 17), were studied. The dogs were classified into three groups: lean, overweight and obese, according to the 5-point Body Condition Score (BCS) scale. In the cohort of Labradors a complete phenotypic data (age, sex, neutering status, body weight and BCS) were collected for 127 dogs. The entire coding sequence as well as 5′ and 3′-flanking regions of the studied gene were sequenced and six polymorphic sites were reported. Genotype frequencies differed considerably between breeds and Labrador Retrievers appeared to be the less polymorphic. Moreover, distribution of some polymorphic variants differed significantly (P < 0.05) between small cohorts with diverse BCS in Golden Retrievers (c.777T>C, c.868C>T and c.*33C>G) and Beagles (c.-435T>C and c.637G>T). On the contrary, in Labradors no association between the studied polymorphisms and BCS or body weight was observed. Methylation analysis, using bisulfite DNA conversion followed by Sanger sequencing, was carried out for 12 dogs with BCS = 3 and 12 dogs with BCS = 5. Two intragenic CpG islands, containing 19 cytosines, were analyzed and the methylation profile did not differ significantly between lean and obese animals. We conclude that an association of the MC4R gene polymorphism with dog obesity or body weight is unlikely, in spite of the fact that some associations were found in small cohorts of Beagles and Golden Retrievers. Also methylation level of this gene is not related with dog adiposity.
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Wang ZQ, Wang W, Shi L, Chai JT, Zhang XJ, Tao YX. Molecular cloning and pharmacological characterization of giant panda (Ailuropoda melanoleuca) melanocortin-4 receptor. Gen Comp Endocrinol 2016; 229:32-40. [PMID: 26896843 DOI: 10.1016/j.ygcen.2016.02.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 02/13/2016] [Accepted: 02/15/2016] [Indexed: 10/22/2022]
Abstract
The melanocortin-4 receptor (MC4R) is critical in regulating mammalian food intake and energy expenditure. Giant panda (Ailuropoda melanoleuca), famous as the living fossil, is an endangered species endemic to China. We are interested in exploring the functions of the giant panda MC4R (amMC4R) in regulating energy homeostasis and report herein the molecular cloning and pharmacology of the amMC4R. Sequence analysis revealed that amMC4R was highly homologous (>88%) at nucleotide and amino acid sequences to several mammalian MC4Rs. Western blot revealed that the expression construct myc-amMC4R in pcDNA3.1 was successfully constructed and expressed in HEK293T cells. With human MC4R (hMC4R) as a control, pharmacological characteristics of amMC4R were analyzed with binding and signaling assays. Four agonists, including [Nle(4), D-Phe(7)]-α-melanocyte stimulating hormone (NDP-MSH), α- and β-MSH, and a small molecule agonist, THIQ, were used in binding and signaling assays. We showed that amMC4R bound NDP-MSH with the highest affinity followed by THIQ, α-MSH, and β-MSH, with the same ranking order as hMC4R. Treatment of HEK293T cells expressing amMC4R with different concentrations of agonists resulted in dose-dependent increase of intracellular cAMP levels, with similar EC50s for the four agonists. The results suggested that the cloned amMC4R encoded a functional MC4R. The availability of amMC4R and its binding and signaling properties will facilitate the investigation of amMC4R in regulating food intake and energy homeostasis.
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Affiliation(s)
- Zhi-Qiang Wang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, People's Republic of China.
| | - Wei Wang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Lin Shi
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, People's Republic of China
| | - Ji-Tian Chai
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, People's Republic of China
| | - Xin-Jun Zhang
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu 225009, People's Republic of China
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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Wang ZQ, Huang JS, Zhou JH, Shi L, Jiang XF, Tao YX. Pharmacologic analyses of four chicken melanocortin-4 receptor mutations. Domest Anim Endocrinol 2016; 54:68-75. [PMID: 26521202 DOI: 10.1016/j.domaniend.2015.06.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 05/12/2015] [Accepted: 06/24/2015] [Indexed: 10/23/2022]
Abstract
The melanocortin-4 receptor (MC4R) is a critical regulator of mammalian food intake and energy expenditure, with receptor activation resulting in decreased food intake and increased energy expenditure. Recently, studies on role of MC4R in regulation of food intake have been extended to other species, such as chicken. Functional study of mutant MC4Rs is important in proving the causal link between MC4R mutation and production traits. Herein, we cloned chicken MC4R (cMC4R) complementary DNA and generated 4 mutant cMC4Rs (Q18H, G21R, S76L, and L299P) by site-directed mutagenesis and measured their expression by flow cytometry. Pharmacologic characteristics were analyzed with binding and signaling assays using 3 agonists. We showed that G21R had decreased cell surface and total expression (P < 0.05), whereas the other 3 mutants had similar total and cell surface expression levels as wild-type cMC4R. The 4 mutants had either decreased (Q18H, G21R, S76L; P < 0.05) or no (L299P) binding to radiolabeled [Nle(4), D-Phe(7)]-α-melanocyte-stimulating hormone (MSH). In signaling assays, Q18H was constitutively active. Q18H, G21R, and S76L had decreased responses to α-MSH stimulation (P < 0.05). L299P had decreased basal and ligand-stimulated signaling (P < 0.01). Nle(4), D-Phe(7)-MSH was the most potent agonist for cMC4R and therefore would be better suited for further in vivo studies. We conclude that the cloned cMC4R was a functional receptor and provided detailed functional data for these mutations, contributing to a better understanding of cMC4R variants associated with production traits.
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Affiliation(s)
- Z-Q Wang
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu 225009, People's Republic of China; Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA.
| | - J-S Huang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA
| | - J-H Zhou
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu 225009, People's Republic of China
| | - L Shi
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu 225009, People's Republic of China
| | - X-F Jiang
- College of Veterinary Medicine, Yangzhou University, Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu 225009, People's Republic of China
| | - Y-X Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, USA.
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11
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Zeng R, Zhang Y, Du P. SNPs of melanocortin 4 receptor (MC4R) associated with body weight in Beagle dogs. Exp Anim 2014; 63:73-8. [PMID: 24521865 PMCID: PMC4160929 DOI: 10.1538/expanim.63.73] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Melanocortin 4 receptor (MC4R), which is associated with inherited human obesity, is involoved in food intake and body weight of mammals. To study the relationships between MC4R gene polymorphism and body weight in Beagle dogs, we detected and compared the nucleotide sequence of the whole coding region and 3'- and 5'- flanking regions of the dog MC4R gene (1214 bp). In 120 Beagle dogs, two SNPs (A420C, C895T) were identified and their relation with body weight was analyzed with RFLP-PCR method. The results showed that the SNP at A420C was significantly associated with canine body weight trait when it changed amino acid 101 of the MC4R protein from asparagine to threonine, while canine body weight variations were significant in female dogs when MC4R nonsense mutation at C895T. It suggested that the two SNPs might affect the MC4R gene's function which was relative to body weight in Beagle dogs. Therefore, MC4R was a candidate gene for selecting different size dogs with the MC4R SNPs (A420C, C895T) being potentially valuable as a genetic marker.
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Affiliation(s)
- Ruixia Zeng
- Department of Human Anatomy, School of Basic Medical Sciences, Liaoning Medical University, Jinzhou 121001, P.R. China
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12
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Tao YX, Conn PM. Chaperoning G protein-coupled receptors: from cell biology to therapeutics. Endocr Rev 2014; 35:602-47. [PMID: 24661201 PMCID: PMC4105357 DOI: 10.1210/er.2013-1121] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 03/14/2014] [Indexed: 12/13/2022]
Abstract
G protein-coupled receptors (GPCRs) are membrane proteins that traverse the plasma membrane seven times (hence, are also called 7TM receptors). The polytopic structure of GPCRs makes the folding of GPCRs difficult and complex. Indeed, many wild-type GPCRs are not folded optimally, and defects in folding are the most common cause of genetic diseases due to GPCR mutations. Both general and receptor-specific molecular chaperones aid the folding of GPCRs. Chemical chaperones have been shown to be able to correct the misfolding in mutant GPCRs, proving to be important tools for studying the structure-function relationship of GPCRs. However, their potential therapeutic value is very limited. Pharmacological chaperones (pharmacoperones) are potentially important novel therapeutics for treating genetic diseases caused by mutations in GPCR genes that resulted in misfolded mutant proteins. Pharmacoperones also increase cell surface expression of wild-type GPCRs; therefore, they could be used to treat diseases that do not harbor mutations in GPCRs. Recent studies have shown that indeed pharmacoperones work in both experimental animals and patients. High-throughput assays have been developed to identify new pharmacoperones that could be used as therapeutics for a number of endocrine and other genetic diseases.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology, and Pharmacology (Y.-X.T.), College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849-5519; and Departments of Internal Medicine and Cell Biology (P.M.C.), Texas Tech University Health Science Center, Lubbock, Texas 79430-6252
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Switonski M, Mankowska M, Salamon S. Family of melanocortin receptor (MCR) genes in mammals-mutations, polymorphisms and phenotypic effects. J Appl Genet 2013; 54:461-72. [PMID: 23996627 PMCID: PMC3825561 DOI: 10.1007/s13353-013-0163-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/11/2013] [Accepted: 07/28/2013] [Indexed: 01/02/2023]
Abstract
The melanocortin receptor gene family consists of five single-exon members, which are located on autosomes. Three genes (MC2R, MC4R and MC5R) are syntenic in the human, mouse, cattle and dog genomes, while in the pig, the syntenic group comprises MC1R, MC2R and MC5R. Two genes (MC1R and MC4R) have been extensively studied due to their function in melanogenesis (MC1R) and energy control (MC4R). Conservative organisation of these genes in five mammalian species (human, mouse, cattle, pig and dog), in terms of the encoded amino acid sequence, is higher in the case of MC4R compared to MC1R. Polymorphisms of these two genes are responsible or associated with variation of pigmentation (MC1R) and adipose tissue deposition (MC4R). Polymorphic variants in MC1R, causing coat colour variation, were described in humans and domestic mammals (cattle, horse, pig, sheep, dog), as well as farm red and arctic foxes. The MC4R gene is very polymorphic in humans and it is well known that some variants cause monogenic obesity or significantly contribute to the development of polygenic obesity. Such relationships are not so evident in domestic mammals; however, at least one missense substitution (298Asp > Asn) in the porcine MC4R significantly contributes, at least in some breeds, to fat tissue accumulation, feed conversion ratio and daily weight gain. Knowledge on the phenotypic effects of polymorphisms of MC2R, MC3R and MC5R in domestic mammals is scarce, probably due to the small number of reports addressing these genes. Thus, further studies focused on these genes should be undertaken.
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Affiliation(s)
- M Switonski
- Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637, Poznan, Poland,
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Switonski M, Mankowska M. Dog obesity--the need for identifying predisposing genetic markers. Res Vet Sci 2013; 95:831-6. [PMID: 24034586 DOI: 10.1016/j.rvsc.2013.08.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 08/14/2013] [Accepted: 08/17/2013] [Indexed: 11/24/2022]
Abstract
Incidence of overweight and obesity in dogs exceeds 30%, and several breeds are predisposed to this heritable phenotype. Rapid progress of canine genomics and advanced knowledge on the genetic background of human obesity bring a unique opportunity to perform such studies in dogs. Natural candidate genes for obesity are these encoding adipokines. Extended studies in humans indicated that polymorphisms of three of them, i.e. ADIPOQ, IL1 and TNF, are associated with predisposition to obesity. On the other hand, the use of genome-wide association studies revealed an association between human obesity and polymorphism of more than 50 other genes. Until now only few preliminary reports on polymorphism of canine FTO, MC4R, MC3R and PPARG genes have been published. Since the dog is a valuable model organism for human diseases one can foresee that such studies may also contribute to an in-depth understanding of human obesity pathogenesis.
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Affiliation(s)
- M Switonski
- Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wołynska 33, 60-637 Poznan, Poland.
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Tao YX, Yuan ZH, Xie J. G Protein-Coupled Receptors as Regulators of Energy Homeostasis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 114:1-43. [DOI: 10.1016/b978-0-12-386933-3.00001-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Skorczyk A, Flisikowski K, Switonski M. A comparative analysis of MC4R gene sequence, polymorphism, and chromosomal localization in Chinese raccoon dog and Arctic fox. DNA Cell Biol 2011; 31:732-8. [PMID: 22047079 DOI: 10.1089/dna.2011.1423] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Numerous mutations of the human melanocortin receptor type 4 (MC4R) gene are responsible for monogenic obesity, and some of them appear to be associated with predisposition or resistance to polygenic obesity. Thus, this gene is considered a functional candidate for fat tissue accumulation and body weight in domestic mammals. The aim of the study was comparative analysis of chromosome localization, nucleotide sequence, and polymorphism of the MC4R gene in two farmed species of the Canidae family, namely the Chinese raccoon dog (Nycterutes procyonoides procyonoides) and the arctic fox (Alopex lagopus). The whole coding sequence, including fragments of 3'UTR and 5'UTR, shows 89% similarity between the arctic fox (1276 bp) and Chinese raccoon dog (1213 bp). Altogether, 30 farmed Chinese raccoon dogs and 30 farmed arctic foxes were searched for polymorphisms. In the Chinese raccoon dog, only one silent substitution in the coding sequence was identified; whereas in the arctic fox, four InDels and two single-nucleotide polymorphisms (SNPs) in the 5'UTR and six silent SNPs in the exon were found. The studied gene was mapped by FISH to the Chinese raccoon dog chromosome 9 (NPP9q1.2) and arctic fox chromosome 24 (ALA24q1.2-1.3). The obtained results are discussed in terms of genome evolution of species belonging to the family Canidae and their potential use in animal breeding.
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Affiliation(s)
- Anna Skorczyk
- Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Poznan, Poland.
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