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Wei R, Li D, Jia S, Chen Y, Wang J. MC4R in Central and Peripheral Systems. Adv Biol (Weinh) 2023; 7:e2300035. [PMID: 37043700 DOI: 10.1002/adbi.202300035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 02/25/2023] [Indexed: 04/14/2023]
Abstract
Obesity has emerged as a critical and urgent health burden during the current global pandemic. Among multiple genetic causes, melanocortin receptor-4 (MC4R), involved in food intake and energy metabolism regulation through various signaling pathways, has been reported to be the lead genetic factor in severe and early onset obesity and hyperphagia disorders. Most previous studies have illustrated the roles of MC4R signaling in energy intake versus expenditure in the central system, while some evidence indicates that MC4R is also expressed in peripheral systems, such as the gut and endocrine organs. However, its physiopathological function remains poorly defined. This review aims to depict the central and peripheral roles of MC4R in energy metabolism and endocrine hormone homeostasis, the diversity of phenotypes, biased downstream signaling caused by distinct MC4R mutations, and current drug development targeting the receptor.
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Affiliation(s)
- Ran Wei
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
- Department of Endocrinology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, 200240, China
| | - Danjie Li
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Sheng Jia
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Yuhong Chen
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
| | - Jiqiu Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, 197 Ruijin 2nd Road, Shanghai, 200025, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai National Center for Translational Medicine, Shanghai, 200025, China
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Copperi F, Kim JD, Diano S. Role of the Melanocortin System in the Central Regulation of Cardiovascular Functions. Front Physiol 2021; 12:725709. [PMID: 34512392 PMCID: PMC8424695 DOI: 10.3389/fphys.2021.725709] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 07/30/2021] [Indexed: 11/18/2022] Open
Abstract
Increasing evidence indicates that the melanocortin system is not only a central player in energy homeostasis, food intake and glucose level regulation, but also in the modulation of cardiovascular functions, such as blood pressure and heart rate. The melanocortins, and in particular α- and γ-MSH, have been shown to exert their cardiovascular activity both at the central nervous system level and in the periphery (e.g., in the adrenal gland), binding their receptors MC3R and MC4R and influencing the activity of the sympathetic nervous system. In addition, some studies have shown that the activation of MC3R and MC4R by their endogenous ligands is able to improve the outcome of cardiovascular diseases, such as myocardial and cerebral ischemia. In this brief review, we will discuss the current knowledge of how the melanocortin system influences essential cardiovascular functions, such as blood pressure and heart rate, and its protective role in ischemic events, with a particular focus on the central regulation of such mechanisms.
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Affiliation(s)
- Francesca Copperi
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
| | - Jung Dae Kim
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
| | - Sabrina Diano
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States.,Department of Molecular Pharmacology and Therapeutics, Columbia University Irving Medical Center, New York, NY, United States.,Department of Physiology and Cellular Biophysics, Columbia University Irving Medical Center, New York, NY, United States
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3
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Pechanova O, Vrankova S, Cebova M. Chronic L-Name-Treatment Produces Hypertension by Different Mechanisms in Peripheral Tissues and Brain: Role of Central eNOS. PATHOPHYSIOLOGY 2020; 27:46-54. [PMID: 35366256 PMCID: PMC8830472 DOI: 10.3390/pathophysiology27010007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/11/2020] [Accepted: 12/11/2020] [Indexed: 12/17/2022] Open
Abstract
The goal of our study was to analyze the time course of the effect of NG-nitro-L-arginine methyl ester (L-NAME) on nitric oxide synthase (NOS) isoforms and nuclear factor–κB (NF-κB) protein expression, total NOS activity, and blood pressure (BP) in rats. Adult 12-week-old male Wistar rats were subjected to treatment with L-NAME (40 mg/kg/day) for four and seven weeks. BP was increased after 4- and 7-week L-NAME treatments. NOS activity decreased after 4-week-L-NAME treatment; however, the 7-week treatment increased NOS activity in the aorta, heart, and kidney, while it markedly decreased NOS activity in the brainstem, cerebellum, and brain cortex. The 4-week-L-NAME treatment increased eNOS expression in the aorta, heart, and kidney and this increase was amplified after 7 weeks of treatment. In the brain regions, eNOS expression remained unchanged after 4-week L-NAME treatment and prolonged treatment led to a significant decrease of eNOS expression in these tissues. NF-κB expression increased in both peripheral and brain tissues after 4 weeks of treatment and prolongation of treatment decreased the expression in the aorta, heart, and kidney. In conclusion, decreased expression of eNOS in the brain regions after 7-week L-NAME treatment may be responsible for a remarkable decrease of NOS activity in these regions. Since the BP increase persisted after 7 weeks of L-NAME treatment, we hypothesize that central regulation of BP may contribute significantly to L-NAME-induced hypertension.
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Hall JE, Mouton AJ, da Silva AA, Omoto ACM, Wang Z, Li X, do Carmo JM. Obesity, kidney dysfunction, and inflammation: interactions in hypertension. Cardiovasc Res 2020; 117:1859-1876. [PMID: 33258945 DOI: 10.1093/cvr/cvaa336] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 10/01/2020] [Accepted: 11/17/2020] [Indexed: 12/20/2022] Open
Abstract
Obesity contributes 65-75% of the risk for human primary (essential) hypertension (HT) which is a major driver of cardiovascular and kidney diseases. Kidney dysfunction, associated with increased renal sodium reabsorption and compensatory glomerular hyperfiltration, plays a key role in initiating obesity-HT and target organ injury. Mediators of kidney dysfunction and increased blood pressure include (i) elevated renal sympathetic nerve activity (RSNA); (ii) increased antinatriuretic hormones such as angiotensin II and aldosterone; (iii) relative deficiency of natriuretic hormones; (iv) renal compression by fat in and around the kidneys; and (v) activation of innate and adaptive immune cells that invade tissues throughout the body, producing inflammatory cytokines/chemokines that contribute to vascular and target organ injury, and exacerbate HT. These neurohormonal, renal, and inflammatory mechanisms of obesity-HT are interdependent. For example, excess adiposity increases the adipocyte-derived cytokine leptin which increases RSNA by stimulating the central nervous system proopiomelanocortin-melanocortin 4 receptor pathway. Excess visceral, perirenal and renal sinus fat compress the kidneys which, along with increased RSNA, contribute to renin-angiotensin-aldosterone system activation, although obesity may also activate mineralocorticoid receptors independent of aldosterone. Prolonged obesity, HT, metabolic abnormalities, and inflammation cause progressive renal injury, making HT more resistant to therapy and often requiring multiple antihypertensive drugs and concurrent treatment of dyslipidaemia, insulin resistance, diabetes, and inflammation. More effective anti-obesity drugs are needed to prevent the cascade of cardiorenal, metabolic, and immune disorders that threaten to overwhelm health care systems as obesity prevalence continues to increase.
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Affiliation(s)
- John E Hall
- Department of Physiology & Biophysics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA.,Mississippi Center for Clinical and Translational Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA
| | - Alan J Mouton
- Department of Physiology & Biophysics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA
| | - Alexandre A da Silva
- Department of Physiology & Biophysics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA
| | - Ana C M Omoto
- Department of Physiology & Biophysics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA
| | - Zhen Wang
- Department of Physiology & Biophysics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA
| | - Xuan Li
- Department of Physiology & Biophysics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA
| | - Jussara M do Carmo
- Department of Physiology & Biophysics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 30216-4505, USA
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5
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Hall JE, do Carmo JM, da Silva AA, Wang Z, Hall ME. Obesity, kidney dysfunction and hypertension: mechanistic links. Nat Rev Nephrol 2020; 15:367-385. [PMID: 31015582 DOI: 10.1038/s41581-019-0145-4] [Citation(s) in RCA: 293] [Impact Index Per Article: 73.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Excessive adiposity raises blood pressure and accounts for 65-75% of primary hypertension, which is a major driver of cardiovascular and kidney diseases. In obesity, abnormal kidney function and associated increases in tubular sodium reabsorption initiate hypertension, which is often mild before the development of target organ injury. Factors that contribute to increased sodium reabsorption in obesity include kidney compression by visceral, perirenal and renal sinus fat; increased renal sympathetic nerve activity (RSNA); increased levels of anti-natriuretic hormones, such as angiotensin II and aldosterone; and adipokines, particularly leptin. The renal and neurohormonal pathways of obesity and hypertension are intertwined. For example, leptin increases RSNA by stimulating the central nervous system proopiomelanocortin-melanocortin 4 receptor pathway, and kidney compression and RSNA contribute to renin-angiotensin-aldosterone system activation. Glucocorticoids and/or oxidative stress may also contribute to mineralocorticoid receptor activation in obesity. Prolonged obesity and progressive renal injury often lead to the development of treatment-resistant hypertension. Patient management therefore often requires multiple antihypertensive drugs and concurrent treatment of dyslipidaemia, insulin resistance, diabetes and inflammation. If more effective strategies for the prevention and control of obesity are not developed, cardiorenal, metabolic and other obesity-associated diseases could overwhelm health-care systems in the future.
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Affiliation(s)
- John E Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA. .,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA.
| | - Jussara M do Carmo
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Alexandre A da Silva
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Zhen Wang
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Michael E Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA.,Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA
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6
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Spradley FT, Palei AC, Anderson CD, Granger JP. Melanocortin-4 Receptor Deficiency Attenuates Placental Ischemia-Induced Hypertension in Pregnant Rats. Hypertension 2019; 73:162-170. [PMID: 30571561 DOI: 10.1161/hypertensionaha.118.12028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Preeclampsia is a pregnancy-specific disorder of new-onset hypertension linked to placental ischemia. While obesity is a major risk factor for preeclampsia, not all obese pregnant women develop pregnancy-induced hypertension or preeclampsia. Previously, we reported that placental ischemia-induced hypertension is dependent upon intact signaling of the sympathetic nervous system. Moreover, in various models of obesity, blockade of MC4R (melanocortin-4 receptor) signaling protects against the development of hypertension via suppression of the sympathetic nervous system. Less is known about this pathway during obese pregnancy. Although blockade of MC4R may lead to increased body weight during pregnancy, we tested the hypothesis that placental ischemia-induced hypertension is attenuated in obese MC4R-deficient pregnant rats. On gestational day 14, MC4R wild-type or heterozygous-deficient (MC4R-def) rats were subjected to chronic placental ischemia via the reduced uterine perfusion pressure procedure or Sham surgery then examined on gestational day 19. In Sham MC4R-def versus Sham wild-type pregnant rats, there was increased body weight, fat mass, and circulating leptin levels but they had similar fetus weights. Reduced uterine perfusion pressure reduced fetus weights in both strains. Reduced uterine perfusion pressure increased blood pressure in wild-type rats but this response was significantly attenuated in MC4R-def rats, although blood pressure was elevated in Sham MC4R-def over Sham wild-type. These data indicate that while obese MC4R-def pregnant rats have higher blood pressure during pregnancy, placental ischemia-induced hypertension is attenuated in obese MC4R-def pregnant rats. Thus, obese women with abnormal MC4R signaling may be less susceptible to the development of placental ischemia-induced hypertension.
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Affiliation(s)
- Frank T Spradley
- From the Department of Surgery (F.T.S., A.C.P., C.D.A.), The University of Mississippi Medical Center, Jackson.,Department of Physiology and Biophysics (F.T.S., J.P.G.), The University of Mississippi Medical Center, Jackson
| | - Ana C Palei
- From the Department of Surgery (F.T.S., A.C.P., C.D.A.), The University of Mississippi Medical Center, Jackson
| | - Christopher D Anderson
- From the Department of Surgery (F.T.S., A.C.P., C.D.A.), The University of Mississippi Medical Center, Jackson
| | - Joey P Granger
- Department of Physiology and Biophysics (F.T.S., J.P.G.), The University of Mississippi Medical Center, Jackson
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Pate AT, Schnell AL, Ennis TA, Samson WK, Yosten GLC. Expression and function of nesfatin-1 are altered by stage of the estrous cycle. Am J Physiol Regul Integr Comp Physiol 2019; 317:R328-R336. [PMID: 31141415 DOI: 10.1152/ajpregu.00249.2018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Nesfatin-1 is a peptide derived from the nucleobindin 2 (Nucb2) precursor protein that has been shown to exert potent effects on appetite and cardiovascular function in male animals. Sex hormones modulate the expression of Nucb2 in several species, including goldfish, mouse, and rat, and human studies have revealed differential expression based on male or female sex. We therefore hypothesized that the ability of nesfatin-1 to increase mean arterial pressure (MAP) would be influenced by stage of the estrous cycle. Indeed, we found that in cycling female Sprague-Dawley rats, nesfatin-1 induced an increase in MAP on diestrus, when both estrogen and progesterone levels are low but not on proestrus or estrus. The effect of nesfatin-1 on MAP was dependent on functional central melanocortin receptors, because the nesfatin-1-induced increase in MAP was abolished by pretreatment with the melanocortin 3/4 receptor antagonist, SHU9119. We previously reported that nesfatin-1 inhibited angiotensin II-induced water drinking in male rats but found no effect of nesfatin-1 in females in diestrus. However, nesfatin-1 enhanced angiotensin II-induced elevations in MAP in females in diestrus but had no effect on males. Finally, in agreement with previous reports, the expression of Nucb2 mRNA in hypothalamus was significantly reduced in female rats in proestrus compared with rats in diestrus. From these data we conclude that the function and expression of nesfatin-1 are modulated by sex hormone status. Further studies are required to determine the contributions of chromosomal sex and individual sex hormones to the cardiovascular effects of nesfatin-1.
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Affiliation(s)
- Alicia T Pate
- Saint Louis College of Pharmacy, St. Louis, Missouri
| | - Abigayle L Schnell
- Department of Pharmacology and Physiology, St. Louis University School of Medicine, St. Louis, Missouri
| | - Teresa A Ennis
- Department of Pharmacology and Physiology, St. Louis University School of Medicine, St. Louis, Missouri
| | - Willis K Samson
- Department of Pharmacology and Physiology, St. Louis University School of Medicine, St. Louis, Missouri
| | - Gina L C Yosten
- Department of Pharmacology and Physiology, St. Louis University School of Medicine, St. Louis, Missouri
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8
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da Silva AA, do Carmo JM, Wang Z, Hall JE. Melanocortin-4 Receptors and Sympathetic Nervous System Activation in Hypertension. Curr Hypertens Rep 2019; 21:46. [PMID: 31028563 DOI: 10.1007/s11906-019-0951-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
PURPOSE OF REVIEW To highlight the role of the brain melanocortin 4 receptor (MC4R) for sympathetic nervous system (SNS) activation in hypertension. RECENT FINDINGS Hypertension is the most significant risk factor for developing cardiovascular disease. Although excess weight gain is associated with at least two thirds of primary hypertension cases, the pathophysiological mechanisms involved remain the subject of intense investigation. Multiple studies demonstrate an important role for increased sympathetic nervous system (SNS) activity in development and maintenance of hypertension, and that the brain MC4R modulates SNS activity to thermogenic, cardiovascular, and kidney tissues. These studies also support the concept that MC4R activation is critical for obesity-induced hypertension as well as other forms of hypertension associated with increased SNS activity. MC4R is a potential target for antiobesity therapy, although there are challenges in using MC4R agonists to induce weight loss without evoking increases in SNS activity.
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Affiliation(s)
- Alexandre A da Silva
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, and Cardiovascular-Renal Research Center, The University of Mississippi Medical Center, 2500 North State St., Jackson, MS, 39216-4505, USA.
| | - Jussara M do Carmo
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, and Cardiovascular-Renal Research Center, The University of Mississippi Medical Center, 2500 North State St., Jackson, MS, 39216-4505, USA
| | - Zhen Wang
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, and Cardiovascular-Renal Research Center, The University of Mississippi Medical Center, 2500 North State St., Jackson, MS, 39216-4505, USA
| | - John E Hall
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, and Cardiovascular-Renal Research Center, The University of Mississippi Medical Center, 2500 North State St., Jackson, MS, 39216-4505, USA
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9
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do Carmo JM, da Silva AA, Moak SP, da Silva FS, Spradley FT, Hall JE. Role of melanocortin 4 receptor in hypertension induced by chronic intermittent hypoxia. Acta Physiol (Oxf) 2019; 225:e13222. [PMID: 30466186 DOI: 10.1111/apha.13222] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 11/13/2018] [Accepted: 11/15/2018] [Indexed: 12/23/2022]
Abstract
AIM We previously demonstrated that central nervous system (CNS) melanocortin 4 receptors (MC4R) play a key role in regulating blood pressure (BP) in some conditions associated with increased SNS activity, including obesity. In this study, we examined whether activation of CNS MC4R contributes to chronic intermittent hypoxia (CIH)-induced hypertension and ventilatory responses to hypercapnia. METHODS Rats were instrumented with an intracerebroventricular (ICV) cannula in the lateral cerebral ventricle for continuous infusion of MC4R antagonist (SHU-9119) and telemetry probes for measuring mean arterial pressure (MAP) and heart rate (HR). Untreated and SHU-9119-treated rats as well as obese and lean MC4R-deficient rats were exposed to CIH for 7-18 consecutive days. RESULTS Chronic intermittent hypoxia reduced cumulative food intake by 18 ± 5 g while MAP and HR increased by 10 ± 3 mm Hg and 9 ± 5 bpm in untreated rats. SHU-9119 increased food intake (from 15 ± 1 to 46 ± 3 g) and prevented CIH-induced reduction in food intake. CIH-induced hypertension was not attenuated by MC4R antagonism (average increase of 10 ± 1 vs 9 ± 1 mm Hg for untreated and SHU-9119 treated rats). In obese MC4R-deficient rats, CIH for 7 days raised BP by 11 ± 4 mm Hg. However, when MC4R-deficient rats were food restricted to prevent obesity, CIH-induced hypertension was attenuated by 32%. We also found that MC4R deficiency was associated with impaired ventilatory responses to hypercapnia independently of obesity. CONCLUSION These results show that obesity and the CNS melanocortin system interact in complex ways to elevate BP during CIH and that MC4R may be important in the ventilatory responses to hypercapnia.
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Affiliation(s)
- Jussara M. do Carmo
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular‐Renal Research Center University of Mississippi Medical Center Jackson Mississippi
| | - Alexandre A. da Silva
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular‐Renal Research Center University of Mississippi Medical Center Jackson Mississippi
- Barão de Mauá University Center Ribeirão Preto Brazil
- Universidade Estadual de Minas Gerais Passos Brazil
| | - Sydney P. Moak
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular‐Renal Research Center University of Mississippi Medical Center Jackson Mississippi
| | - Fernanda S. da Silva
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular‐Renal Research Center University of Mississippi Medical Center Jackson Mississippi
- Barão de Mauá University Center Ribeirão Preto Brazil
| | - Frank T. Spradley
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular‐Renal Research Center University of Mississippi Medical Center Jackson Mississippi
- Department of Surgery University of Mississippi Medical Center Jackson Mississippi
| | - John E. Hall
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular‐Renal Research Center University of Mississippi Medical Center Jackson Mississippi
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Abstract
Obesity greatly increases the risk for cardiovascular, metabolic, and renal diseases and is one of the most significant and preventable causes of increased blood pressure (BP) in patients with essential hypertension. This review highlights recent advances in our understanding of central nervous system (CNS) signaling pathways that contribute to the etiology and pathogenesis of obesity-induced hypertension. We discuss the role of excess adiposity and activation of the brain leptin-melanocortin system in causing increased sympathetic activity in obesity. In addition, we highlight other potential brain mechanisms by which increased weight gain modulates metabolic and cardiovascular functions. Unraveling the CNS mechanisms responsible for increased sympathetic activation and hypertension and how circulating hormones activate brain signaling pathways to control BP offer potentially important therapeutic targets for obesity and hypertension.
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11
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do Carmo JM, da Silva AA, Wang Z, Fang T, Aberdein N, Perez de Lara CE, Hall JE. Role of the brain melanocortins in blood pressure regulation. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2508-2514. [PMID: 28274841 DOI: 10.1016/j.bbadis.2017.03.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 02/27/2017] [Accepted: 03/02/2017] [Indexed: 10/20/2022]
Abstract
Melanocortins play an important role in regulating blood pressure (BP) and sympathetic nervous system (SNS) activity as well as energy balance, glucose and other metabolic functions in humans and experimental animals. In experimental models of hypertension with high SNS activity, blockade of the melanocortin-4 receptor (MC4R) reduces BP despite causing marked hyperphagia and obesity. Activation of the central nervous system (CNS) pro-opiomelanocortin (POMC)-MC4R pathway appears to be an important link between obesity, SNS activation and hypertension. Despite having severe obesity, subjects with MC4R deficiency exhibit reductions in BP, heart rate, and urinary catecholamine excretion, as well as attenuated SNS responses to cold stimuli compared to obese subjects with normal MC4R function. In this review we discuss the importance of the brain POMC-MC4R system in regulating SNS activity and BP in obesity and other forms of hypertension. We also highlight potential mechanisms and brain circuitry by which the melanocortin system regulates cardiovascular function.
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Affiliation(s)
- Jussara M do Carmo
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA.
| | - Alexandre A da Silva
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA; Barão de Mauá University Center, Ribeirão Preto, São Paulo, Brazil; Universidade Estadual de Minas Gerais, Passos, Minas Gerais, Brazil
| | - Zhen Wang
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
| | - Taolin Fang
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
| | - Nicola Aberdein
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
| | - Cecilia E Perez de Lara
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
| | - John E Hall
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, MS, USA
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Spradley FT, Sasser JM, Musall JB, Sullivan JC, Granger JP. Nitric oxide synthase-mediated blood pressure regulation in obese melanocortin-4 receptor-deficient pregnant rats. Am J Physiol Regul Integr Comp Physiol 2016; 311:R851-R857. [PMID: 27534879 DOI: 10.1152/ajpregu.00285.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/14/2016] [Indexed: 11/22/2022]
Abstract
Although obesity increases the risk for hypertension in pregnancy, the mechanisms responsible are unknown. Increased nitric oxide (NO) production results in vasodilation and reduced blood pressure during normal pregnancy in lean rats; however, the role of NO is less clear during obese pregnancies. We examined the impact of obesity on NO synthase (NOS)-mediated regulation of blood pressure during pregnancy by testing the hypothesis that NOS activity, expression, and regulation of vascular tone and blood pressure are reduced in obese pregnant rats. At gestational day 19, melanocortin-4 receptor (MC4R)-deficient obese rats (MC4R) had greater body weight and fat mass with elevated blood pressure and circulating sFlt-1 levels compared with MC4R pregnant rats. MC4R pregnant rats also had less circulating cGMP levels and reduced total NOS enzymatic activity and expression in mesenteric arteries. Despite decreased biochemical measures of NO/NOS in MC4R rats, NOS inhibition enhanced vasoconstriction only in mesenteric arteries from MC4R rats, suggesting greater NOS-mediated tone. To examine the role of NOS on blood pressure regulation in obese pregnant rats, MC4R and MC4R pregnant rats were administered the nonselective NOS inhibitor NG-nitro-l-arginine methyl ester (l-NAME, 100 mg/l) from gestational day 14 to 19 in drinking water. The degree by which l-NAME raised blood pressure was similar between obese and lean pregnant rats. Although MC4R obese pregnant rats had elevated blood pressure associated with reduced total NOS activity and expression, they had enhanced NOS-mediated attenuation of vasoconstriction, with no evidence of alterations in NOS-mediated regulation of blood pressure.
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Affiliation(s)
- Frank T Spradley
- Department of Surgery, The University of Mississippi Medical Center, Jackson, Mississippi; .,Department of Physiology and Biophysics, The University of Mississippi Medical Center, Jackson, Mississippi.,Cardiovascular-Renal Research Center, The University of Mississippi Medical Center, Jackson, Mississippi.,Women's Health Research Center, The University of Mississippi Medical Center, Jackson, Mississippi; and
| | - Jennifer M Sasser
- Department of Pharmacology and Toxicology, The University of Mississippi Medical Center, Jackson, Mississippi.,Cardiovascular-Renal Research Center, The University of Mississippi Medical Center, Jackson, Mississippi.,Women's Health Research Center, The University of Mississippi Medical Center, Jackson, Mississippi; and
| | | | | | - Joey P Granger
- Department of Physiology and Biophysics, The University of Mississippi Medical Center, Jackson, Mississippi.,Cardiovascular-Renal Research Center, The University of Mississippi Medical Center, Jackson, Mississippi.,Women's Health Research Center, The University of Mississippi Medical Center, Jackson, Mississippi; and
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do Carmo JM, da Silva AA, Moak SP, Houghton HJ, Smith A, Hall JE. Regulation of Blood Pressure, Appetite, and Glucose by CNS Melanocortin System in Hyperandrogenemic Female SHR. Am J Hypertens 2016; 29:832-40. [PMID: 26584577 DOI: 10.1093/ajh/hpv182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 10/20/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Hyperandrogenemia in females may be associated with sympathetic nervous system (SNS) activation and increased blood pressure (BP). However the importance of hyperandrogenemia in causing hypertension in females and the mechanisms involved are still unclear. We tested whether chronic hyperandrogenemia exacerbates hypertension in young female spontaneously hypertensive rats (SHR) and whether endogenous melanocortin-3/4 receptor (MC3/4R) activation contributes to the elevated BP. METHODS Cardiovascular and metabolic effects of chronic MC3/4R antagonism were assessed in female SHR treated with dihydrotestosterone (DHT, beginning at 5 weeks of age) and placebo-treated female SHR. BP and heart rate (HR) were measured by telemetry and an intracerebroventricular (ICV) cannula was placed in the lateral ventricle for infusions. After control measurements, the MC3/4R antagonist (SHU-9119) was infused for 10 days (1 nmol/hour, ICV, at 15 weeks of age) followed by a 5-day recovery period. RESULTS MC3/4R antagonism increased food intake and body weight in DHT-treated SHR (14±1 to 35±1g/day and 244±3 to 298±8g) and controls (14±1 to 34±2g/day and 207±4 to 269±8g). Compared to untreated SHR, DHT-treated SHR had similar BP but lower HR (146±3 vs. 142±4mm Hg and 316±2 vs. 363±4 bpm). Chronic SHU-9119 infusion reduced BP and HR in DHT-treated SHR (-12±2mm Hg and -14±4 bpm) and control female SHR (-19±2mm Hg and -21±6 bpm). CONCLUSION These results indicate that hyperandrogenemia does not exacerbate hypertension in female SHR. MC3/4R antagonism reduces BP and HR despite marked increases in food intake and body weight in hyperandrogenemic and control female SHR.
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Affiliation(s)
- Jussara M do Carmo
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA;
| | - Alexandre A da Silva
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA; Barão de Mauá University Center, Ribeirão Preto, São Paulo, Brazil
| | - Sydney P Moak
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Haley J Houghton
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Andrew Smith
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA; Department of Radiology, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - John E Hall
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi, USA
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In vivo organ specific drug delivery with implantable peristaltic pumps. Sci Rep 2016; 6:26251. [PMID: 27185292 PMCID: PMC4869096 DOI: 10.1038/srep26251] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 04/29/2016] [Indexed: 12/20/2022] Open
Abstract
Classic methods for delivery of agents to specific organs are technically challenging and causes superfluous stress. The current study describes a method using programmable, implantable peristaltic pumps to chronically deliver drugs in vivo, while allowing animals to remain undisturbed for accurate physiological measurements. In this study, two protocols were used to demonstrate accurate drug delivery to the renal medulla. First, the vasopressin receptor-2 agonist, dDAVP, was delivered to the renal medulla resulting in a significant increase in water retention, urine osmolality and aquaporin-2 expression and phosphorylation. Second, in a separate group of rats, the histone deacetylase (HDAC) inhibitor, MS275, was delivered to the renal medulla. HDAC inhibition resulted in a significant increase in histone H3-acetylation, the hallmark for histone deacetylase inhibition. However, this was confined to the medulla, as the histone H3-acetylation was similar in the cortex of vehicle and MS275 infused rats, suggesting targeted drug delivery without systemic spillover. Thus, implantable, peristaltic pumps provide a number of benefits compared to externalized chronic catheters and confer specific delivery to target organs.
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Role of hindbrain melanocortin-4 receptor activity in controlling cardiovascular and metabolic functions in spontaneously hypertensive rats. J Hypertens 2016; 33:1201-6. [PMID: 25668357 DOI: 10.1097/hjh.0000000000000530] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Although we previously demonstrated that activation of central nervous system (CNS) melanocortin3/4 receptors (MC3/4R) play a key role in blood pressure (BP) regulation, especially in spontaneously hypertensive rats (SHRs), the importance of hindbrain MC4R is still unclear. METHOD In the present study, we examined the cardiovascular and metabolic effects of chronic inhibition of MC3/4R in the hindbrain of SHRs and normotensive Wistar-Kyoto (WKY) rats. Male WKY rats (n = 6) and SHRs (n = 7) were implanted with telemetry probes to measure BP and heart rate (HR) 24 h/day, and an intracerebroventricular cannula was placed into the fourth ventricle. After 10 days of recovery and 5 days of control measurements, the MC3/4R antagonist (SHU-9119) was infused into the fourth ventricle (1 nmol/h) to antagonize hindbrain MC4R for 10 days, followed by a 5-day recovery period. RESULTS Chronic hindbrain MC3/4R antagonism significantly increased food intake and body weight in WKY rats (17 ± 1 to 35 ± 2 g/day and 280 ± 8 to 353 ± 8 g) and SHRs (19 ± 2 to 35 ± 2 g/day and 323 ± 7 to 371 ± 11 g), and markedly increased fasting insulin and leptin levels while causing no changes in blood glucose levels (99 ± 4 to 87 ± 4 and 89 ± 5 to 89 ± 4 mg/dl, respectively, for WKY rats and SHRs). Chronic SHU-9119 infusion reduced mean arterial pressure and HR similarly in WKY rats (-8 ± 1 mmHg and -47 ± 3 b.p.m.) and SHRs (-11 ± 3 mmHg and -44 ± 3 b.p.m.). CONCLUSION These results suggest that although hindbrain MC4R activity contributes to appetite and HR regulation, it does not play a major role in mediating the elevated BP in SHRs.
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Hall JE, do Carmo JM, da Silva AA, Wang Z, Hall ME. Obesity-induced hypertension: interaction of neurohumoral and renal mechanisms. Circ Res 2015; 116:991-1006. [PMID: 25767285 DOI: 10.1161/circresaha.116.305697] [Citation(s) in RCA: 680] [Impact Index Per Article: 75.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Excess weight gain, especially when associated with increased visceral adiposity, is a major cause of hypertension, accounting for 65% to 75% of the risk for human primary (essential) hypertension. Increased renal tubular sodium reabsorption impairs pressure natriuresis and plays an important role in initiating obesity hypertension. The mediators of abnormal kidney function and increased blood pressure during development of obesity hypertension include (1) physical compression of the kidneys by fat in and around the kidneys, (2) activation of the renin-angiotensin-aldosterone system, and (3) increased sympathetic nervous system activity. Activation of the renin-angiotensin-aldosterone system is likely due, in part, to renal compression, as well as sympathetic nervous system activation. However, obesity also causes mineralocorticoid receptor activation independent of aldosterone or angiotensin II. The mechanisms for sympathetic nervous system activation in obesity have not been fully elucidated but may require leptin and activation of the brain melanocortin system. With prolonged obesity and development of target organ injury, especially renal injury, obesity-associated hypertension becomes more difficult to control, often requiring multiple antihypertensive drugs and treatment of other risk factors, including dyslipidemia, insulin resistance and diabetes mellitus, and inflammation. Unless effective antiobesity drugs are developed, the effect of obesity on hypertension and related cardiovascular, renal and metabolic disorders is likely to become even more important in the future as the prevalence of obesity continues to increase.
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Affiliation(s)
- John E Hall
- From the Departments of Physiology and Biophysics (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), Medicine (M.E.H.), Mississippi Center for Obesity Research (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), and Cardiovascular-Renal Research Center (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), University of Mississippi Medical Center, Jackson.
| | - Jussara M do Carmo
- From the Departments of Physiology and Biophysics (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), Medicine (M.E.H.), Mississippi Center for Obesity Research (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), and Cardiovascular-Renal Research Center (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), University of Mississippi Medical Center, Jackson
| | - Alexandre A da Silva
- From the Departments of Physiology and Biophysics (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), Medicine (M.E.H.), Mississippi Center for Obesity Research (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), and Cardiovascular-Renal Research Center (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), University of Mississippi Medical Center, Jackson
| | - Zhen Wang
- From the Departments of Physiology and Biophysics (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), Medicine (M.E.H.), Mississippi Center for Obesity Research (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), and Cardiovascular-Renal Research Center (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), University of Mississippi Medical Center, Jackson
| | - Michael E Hall
- From the Departments of Physiology and Biophysics (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), Medicine (M.E.H.), Mississippi Center for Obesity Research (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), and Cardiovascular-Renal Research Center (J.E.H., J.M.d.C., A.A.d.S., Z.W., M.E.H.), University of Mississippi Medical Center, Jackson
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