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Wang Z, do Carmo JM, da Silva AA, Fu Y, Jaynes LT, Sears J, Li X, Mouton AJ, Omoto ACM, Xu BP, Hall JE. Transient receptor potential cation channel 6 (TRPC6) deficiency leads to increased body weight and metabolic dysfunction. Am J Physiol Regul Integr Comp Physiol 2022; 323:R81-R97. [PMID: 35537100 DOI: 10.1152/ajpregu.00097.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
TRPC6, a member of the TRPC family, is expressed in the hypothalamus and modulates cell Ca2+ influx. However, the role of TRPC6 in controlling metabolic and cardiovascular functions under normal conditions has not been previously determined. Thus, the impacts of TRPC6 deletion on energy balance, metabolic and cardiovascular regulation as well as the anorexic responses to leptin and melanocortin 3/4 receptor (MC3/4R) activation were investigated in this study. Extensive cardiometabolic phenotyping was conducted in male and female TRPC6 knock out (KO) and control mice from 6 to 24 weeks of age to assess mechanisms by which TRPC6 influences regulation of energy balance and blood pressure (BP). We found that TRPC6 KO mice are heavier with greater adiposity, hyperphagic, and have reduced energy expenditure, impaired glucose tolerance, hyperinsulinemia, and increased liver fat compared to controls. TRPC6 KO mice also have smaller brains, reduced POMC mRNA levels in the hypothalamus, and impaired anorexic response to leptin but not to MC3/4R activation. BP and heart rate, assessed by telemetry, were similar in TRPC6 KO and control mice, and BP responses to air-jet stress were attenuated in TRPC6 KO mice despite increased body weight and metabolic disorders that normally raise BP and increase BP responses to stress. Our results provide evidence for a novel and important role of TRPC6 in controlling energy balance, adiposity, and glucose homeostasis, which suggests that normal TRPC6 function may be necessary to link weight gain and hyperleptinemia with BP responses to acute stress.
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Affiliation(s)
- Zhen Wang
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
| | - Jussara M do Carmo
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
| | - Alexandre A da Silva
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
| | - Yiling Fu
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
| | - Lance T Jaynes
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
| | - Jaylan Sears
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
| | - Xuan Li
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
| | - Alan J Mouton
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
| | - Ana C M Omoto
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
| | - Brittney P Xu
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
| | - John E Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States
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2
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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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3
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Lu SC, Akanji AO. Leptin, Obesity, and Hypertension: A Review of Pathogenetic Mechanisms. Metab Syndr Relat Disord 2020; 18:399-405. [PMID: 32876506 DOI: 10.1089/met.2020.0065] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The adipokine leptin is expressed at higher concentrations in obese subjects, who also incidentally have a higher prevalence of hypertension. The pathogenesis of this obesity-related hypertension is controversial and is believed to be related to many factors including increased sympathetic activity, abnormalities of the renin-angiotensin system, sodium retention, and an endotheliopathy acting independently or in concert with increased circulating leptin. This review discusses the potential mechanisms through which changes in leptin signal transduction pathways in tissues with the leptin receptor, especially the hypothalamus, mediate the pathogenetic relationships between obesity and hypertension. The hypothesis is explored that leptin effects on blood pressure (BP) are meditated by the downstream effects of hypothalamic leptin signaling and ultimately result in activation of specific melanocortin receptors located on sympathetic neurons in the spinal cord. The physiological consequences of this sympathetic activation of the heart and kidney are activation of the renin-angiotensin system, sodium retention and circulatory expansion and finally, elevated BP. This sequence of events has been elegantly demonstrated with leptin infusion and gene knockout studies in animal models but has not been convincingly reproducibly confirmed in humans. Further studies in human subjects on the specific roles of hypothalamic leptin in essential hypertension are indicated as elucidation of the signaling pathways should provide better understanding of the role of weight loss in BP control and afford an additional mechanism for pharmacologic control of BP in adults and children at risk of cardiovascular disease.
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Affiliation(s)
- Song Chi Lu
- Department of Medical Sciences, Frank H. Netter School of Medicine, NH-MED, Quinnipiac University, Hamden, Connecticut, USA
| | - Abayomi O Akanji
- Department of Medical Sciences, Frank H. Netter School of Medicine, NH-MED, Quinnipiac University, Hamden, Connecticut, USA
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da Silva Teixeira S, Harrison K, Uzodike M, Rajapakshe K, Coarfa C, He Y, Xu Y, Sisley S. Vitamin D actions in neurons require the PI3K pathway for both enhancing insulin signaling and rapid depolarizing effects. J Steroid Biochem Mol Biol 2020; 200:105690. [PMID: 32408067 PMCID: PMC7397709 DOI: 10.1016/j.jsbmb.2020.105690] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 03/23/2020] [Accepted: 04/29/2020] [Indexed: 12/15/2022]
Abstract
Despite correlations between low vitamin D levels and diabetes incidence/severity, supplementation with vitamin D has not been widely effective in improving glucose parameters. This may be due to a lack of knowledge regarding how low vitamin D levels physiologically affect glucose homeostasis. We have previously shown that the brain may be a critical area for vitamin d-mediated action on peripheral glucose levels. However, the mechanisms for how vitamin D acts in the brain are unknown. We utilized a multimodal approach to determine the mechanisms by which vitamin D may act in the brain. We first performed an unbiased search (RNA-sequencing) for pathways affected by vitamin D. Vitamin D (125-dihydroxyvitamin D3; 1,25D3) delivered directly into the third ventricle of obese animals differentially regulated multiple pathways, including the insulin signaling pathway. The insulin signaling pathway includes PI3K, which is important in the brain for glucose regulation. Since others have shown that vitamin D acts through the PI3K pathway in non-neuronal cells (muscle and bone), we hypothesized that vitamin D may act in neurons through a PI3K-dependent pathway. In a hypothalamic cell-culture model (GT1-7 cells), we demonstrate that 1,25D3 increased phosphorylation of Akt in the presence of insulin. However, this was blocked with pre-treatment of wortmannin, a PI3K inhibitor. 1,25D3 increased gene transcription of several genes within the PI3K pathway, including Irs2 and p85, without affecting expression of InsR or Akt. Since we had previously shown that 1,25D3 has significant effects on neuronal function, we also tested if the PI3K pathway could mediate rapid actions of vitamin D. We found that 1,25D3 increased the firing frequency of neurons through a PI3K-dependent mechanism. Collectively, these data support that vitamin D enhances insulin signaling and neuronal excitability through PI3K dependent processes which involve both transcriptional and membrane-initiated signaling events.
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Affiliation(s)
- Silvania da Silva Teixeira
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, United States
| | - Keisha Harrison
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, United States
| | | | - Kimal Rajapakshe
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, United States; Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, 77030, United States
| | - Cristian Coarfa
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, United States; Dan L Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, 77030, United States; Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX, 77030, United States
| | - Yanlin He
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, United States
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, United States
| | - Stephanie Sisley
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, 77030, United States.
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Abstract
PURPOSE OF REVIEW In this brief review, we highlight studies that have contributed to our current understanding of glucose homeostasis by the central nervous system (CNS) leptin-melanocortin system, particularly proopiomelanocortin neurons and melanocortin-4 receptors (MC4R). RECENT FINDINGS Leptin deficiency is associated with insulin resistance and impaired glucose metabolism whereas leptin administration improves tissue glucose uptake/oxidation and reduces hepatic glucose output. These antidiabetic effects of leptin have been demonstrated in experimental animals and humans, even when circulating insulin levels are barely detectable. Recent evidence suggests that these antidiabetic actions of leptin are mediated, in large part, by stimulation of leptin receptors (LRs) in the CNS and require activation of proopiomelanocortin (POMC) neurons and MC4R. These chronic antidiabetic effects of the CNS leptin-melanocortin system appear to be independent of autonomic nervous system and pituitary-thyroid-adrenal (PTA) axis mechanisms. The powerful antidiabetic actions of the CNS leptin-melanocortin system are capable of normalizing plasma glucose even in the absence of insulin and involve interactions of multiple neuronal populations and intracellular signaling pathways. Although the links between the CNS leptin-melanocortin system and its chronic effects on peripheral tissue glucose metabolism are still uncertain, they are independent of insulin action, activation of the autonomic nervous system, or the PTA axis. Unraveling the pathways that contribute to the powerful antidiabetic effects of the CNS leptin-melanocortin system may provide novel therapeutic approaches for diabetes mellitus.
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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, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216-4505, USA.
| | - Jussara M do Carmo
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, and Cardiovascular-Renal Research Center, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216-4505, USA
| | - John E Hall
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, and Cardiovascular-Renal Research Center, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216-4505, USA
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Salazar J, Chávez-Castillo M, Rojas J, Ortega A, Nava M, Pérez J, Rojas M, Espinoza C, Chacin M, Herazo Y, Angarita L, Rojas DM, D'Marco L, Bermudez V. Is "Leptin Resistance" Another Key Resistance to Manage Type 2 Diabetes? Curr Diabetes Rev 2020; 16:733-749. [PMID: 31886750 DOI: 10.2174/1573399816666191230111838] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 11/08/2019] [Accepted: 12/12/2019] [Indexed: 02/06/2023]
Abstract
Although novel pharmacological options for the treatment of type 2 diabetes mellitus (DM2) have been observed to modulate the functionality of several key organs in glucose homeostasis, successful regulation of insulin resistance (IR), body weight management, and pharmacological treatment of obesity remain notable problems in endocrinology. Leptin may be a pivotal player in this scenario, as an adipokine which centrally regulates appetite and energy balance. In obesity, excessive caloric intake promotes a low-grade inflammatory response, which leads to dysregulations in lipid storage and adipokine secretion. In turn, these entail alterations in leptin sensitivity, leptin transport across the blood-brain barrier and defects in post-receptor signaling. Furthermore, hypothalamic inflammation and endoplasmic reticulum stress may increase the expression of molecules which may disrupt leptin signaling. Abundant evidence has linked obesity and leptin resistance, which may precede or occur simultaneously to IR and DM2. Thus, leptin sensitivity may be a potential early therapeutic target that demands further preclinical and clinical research. Modulators of insulin sensitivity have been tested in animal models and small clinical trials with promising results, especially in combination with agents such as amylin and GLP-1 analogs, in particular, due to their central activity in the hypothalamus.
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Affiliation(s)
- Juan Salazar
- Endocrine and Metabolic Diseases Research Center, School of Medicine, The University of Zulia, Maracaibo, Venezuela
| | - Mervin Chávez-Castillo
- Endocrine and Metabolic Diseases Research Center, School of Medicine, The University of Zulia, Maracaibo, Venezuela
| | - Joselyn Rojas
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Angel Ortega
- Endocrine and Metabolic Diseases Research Center, School of Medicine, The University of Zulia, Maracaibo, Venezuela
| | - Manuel Nava
- Endocrine and Metabolic Diseases Research Center, School of Medicine, The University of Zulia, Maracaibo, Venezuela
| | - José Pérez
- Endocrine and Metabolic Diseases Research Center, School of Medicine, The University of Zulia, Maracaibo, Venezuela
| | - Milagros Rojas
- Endocrine and Metabolic Diseases Research Center, School of Medicine, The University of Zulia, Maracaibo, Venezuela
| | | | - Maricarmen Chacin
- Universidad Simon Bolivar, Facultad de Ciencias de la Salud, Barranquilla, Colombia
| | - Yaneth Herazo
- Universidad Simon Bolivar, Facultad de Ciencias de la Salud, Barranquilla, Colombia
| | - Lissé Angarita
- Escuela de Nutricion y Dietetica, Facultad de Medicina, Universidad Andres Bello, Sede Concepcion, Chile
| | - Diana Marcela Rojas
- Escuela de Nutricion y Dietética, Facultad de Medicina, Universidad Andres Bello, Santiago, Chile
| | - Luis D'Marco
- Hospital Clinico de Valencia, INCLIVA, Servicio de Nefrologia, Valencia, Spain
| | - Valmore Bermudez
- Universidad Simon Bolivar, Facultad de Ciencias de la Salud, Barranquilla, Colombia
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do Carmo JM, da Silva AA, Gava FN, Moak SP, Dai X, Hall JE. Impact of leptin deficiency compared with neuronal-specific leptin receptor deletion on cardiometabolic regulation. Am J Physiol Regul Integr Comp Physiol 2019; 317:R552-R562. [PMID: 31411897 DOI: 10.1152/ajpregu.00077.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The main goal of this study was to compare the impact of total body leptin deficiency with neuronal-specific leptin receptor (LR) deletion on metabolic and cardiovascular regulation. Liver fat, diacylglycerol acyltransferase-2 (DGTA2), and CD36 protein content were measured in wild-type (WT), nervous system LR-deficient (LR/Nestin-Cre), and leptin deficient (ob/ob) mice. Blood pressure (BP) and heart rate (HR) were recorded by telemetry, and motor activity (MA) and oxygen consumption (V̇o2) were monitored at 24 wk of age. Female and male LR/Nestin-Cre and ob/ob mice were heavier than WT mice (62 ± 5 and 61 ± 3 vs. 31 ± 1 g) and hyperphagic (6.2 ± 0.5 and 6.1 ± 0.7 vs. 3.5 ± 1.0 g/day), with reduced V̇o2 (27 ± 1 and 33 ± 1 vs 49 ± 3 ml·kg-1·min-1) and decreased MA (3 ± 1 and 7 ± 2 vs 676 ± 105 cm/h). They were also hyperinsulinemic and hyperglycemic compared with WT mice. LR/Nestin-Cre mice had high levels of plasma leptin, while ob/ob mice had undetectable leptin levels. Despite comparable obesity, LR/Nestin-Cre mice had lower liver fat content, DGTA2, and CD36 protein levels than ob/ob mice. Male WT, LR/Nestin-Cre, and ob/ob mice exhibited similar BP (111 ± 3, 110 ± 1 and 109 ± 2 mmHg). Female LR/Nestin-Cre and ob/ob mice, however, had higher BP than WT females despite similar metabolic phenotypes compared with male LR/Nestin-Cre and ob/ob mice. These results indicate that although nervous system LRs play a crucial role in regulating body weight and glucose homeostasis, peripheral LRs regulate liver fat deposition. In addition, our results suggest potential sex differences in the impact of obesity on BP regulation.
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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
| | - Fabio N Gava
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi
| | - Sydney P Moak
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi
| | - Xuemei Dai
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, 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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8
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Chatmethakul T, Roghair RD. Risk of hypertension following perinatal adversity: IUGR and prematurity. J Endocrinol 2019; 242:T21-T32. [PMID: 30657741 PMCID: PMC6594910 DOI: 10.1530/joe-18-0687] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 01/18/2019] [Indexed: 12/12/2022]
Abstract
Consistent with the paradigm shifting observations of David Barker and colleagues that revealed a powerful relationship between decreased weight through 2 years of age and adult disease, intrauterine growth restriction (IUGR) and preterm birth are independent risk factors for the development of subsequent hypertension. Animal models have been indispensable in defining the mechanisms responsible for these associations and the potential targets for therapeutic intervention. Among the modifiable risk factors, micronutrient deficiency, physical immobility, exaggerated stress hormone exposure and deficient trophic hormone production are leading candidates for targeted therapies. With the strong inverse relationship seen between gestational age at delivery and the risk of hypertension in adulthood trumping all other major cardiovascular risk factors, improvements in neonatal care are required. Unfortunately, therapeutic breakthroughs have not kept pace with rapidly improving perinatal survival, and groundbreaking bench-to-bedside studies are urgently needed to mitigate and ultimately prevent the tsunami of prematurity-related adult cardiovascular disease that may be on the horizon. This review highlights our current understanding of the developmental origins of hypertension and draws attention to the importance of increasing the availability of lactation consultants, nutritionists, pharmacists and physical therapists as critical allies in the battle that IUGR or premature infants are waging not just for survival but also for their future cardiometabolic health.
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Affiliation(s)
- Trassanee Chatmethakul
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Robert D Roghair
- Stead Family Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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9
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Wang Z, do Carmo JM, da Silva AA, Bailey KC, Aberdein N, Moak SP, Hall JE. Role of SOCS3 in POMC neurons in metabolic and cardiovascular regulation. Am J Physiol Regul Integr Comp Physiol 2019; 316:R338-R351. [PMID: 30673296 PMCID: PMC6483217 DOI: 10.1152/ajpregu.00163.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 01/16/2019] [Accepted: 01/17/2019] [Indexed: 02/08/2023]
Abstract
Suppressor of cytokine signaling 3 (SOCS3) is a negative regulator of leptin signaling. We previously showed that the chronic effects of leptin on blood pressure (BP) and glucose regulation are mediated by stimulation of proopiomelanocortin (POMC) neurons. In this study we examined the importance of endogenous SOCS3 in POMC neurons in control of metabolic and cardiovascular function and potential sex differences. Male and female SOCS3flox/flox/POMC-Cre mice in which SOCS3 was selectively deleted in POMC neurons and control SOCS3flox/flox mice were studied during a control diet (CD) or a high-fat diet (HFD) and during chronic leptin infusion. Body weight was lower in male and female SOCS3flox/flox/POMC-Cre than control mice fed the CD, despite similar food intake. Male SOCS3flox/flox/POMC-Cre mice exhibited increased energy expenditure. BP and heart rate were similar in male and female SOCS3flox/flox/POMC-Cre and control mice fed the CD. HFD-fed male and female SOCS3flox/flox/POMC-Cre mice showed attenuated weight gain. HFD-induced elevations in baseline BP and BP responses to an air-jet stress test were greater in female SOCS3flox/flox/POMC-Cre than control mice. Chronic leptin infusion produced similar responses for food intake, body weight, oxygen consumption, blood glucose, BP, and heart rate in all groups. Thus SOCS3 deficiency in POMC neurons influences body weight regulation in the setting of CD and HFD and differentially affects BP and energy balance in a sex-specific manner but does not amplify the dietary, glycemic, or cardiovascular effects of leptin.
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Affiliation(s)
- Zhen Wang
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
| | - Jussara M do Carmo
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
| | - Alexandre A da Silva
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
| | - Kandice C Bailey
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
| | - Nicola Aberdein
- Biomolecular Science Research Centre, Sheffield Hallam University , Sheffield , United Kingdom
| | - Sydney P Moak
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
| | - John E Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, Mississippi
- Mississippi Center for Obesity Research, University of Mississippi Medical Center , Jackson, Mississippi
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10
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Baldini G, Phelan KD. The melanocortin pathway and control of appetite-progress and therapeutic implications. J Endocrinol 2019; 241:R1-R33. [PMID: 30812013 PMCID: PMC6500576 DOI: 10.1530/joe-18-0596] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 01/22/2019] [Indexed: 12/19/2022]
Abstract
The initial discovery that ob/ob mice become obese because of a recessive mutation of the leptin gene has been crucial to discover the melanocortin pathway to control appetite. In the melanocortin pathway, the fed state is signaled by abundance of circulating hormones such as leptin and insulin, which bind to receptors expressed at the surface of pro-opiomelanocortin (POMC) neurons to promote processing of POMC to the mature hormone α-melanocyte-stimulating hormone (α-MSH). The α-MSH released by POMC neurons then signals to decrease energy intake by binding to melanocortin-4 receptor (MC4R) expressed by MC4R neurons to the paraventricular nucleus (PVN). Conversely, in the 'starved state' activity of agouti-related neuropeptide (AgRP) and of neuropeptide Y (NPY)-expressing neurons is increased by decreased levels of circulating leptin and insulin and by the orexigenic hormone ghrelin to promote food intake. This initial understanding of the melanocortin pathway has recently been implemented by the description of the complex neuronal circuit that controls the activity of POMC, AgRP/NPY and MC4R neurons and downstream signaling by these neurons. This review summarizes the progress done on the melanocortin pathway and describes how obesity alters this pathway to disrupt energy homeostasis. We also describe progress on how leptin and insulin receptors signal in POMC neurons, how MC4R signals and how altered expression and traffic of MC4R change the acute signaling and desensitization properties of the receptor. We also describe how the discovery of the melanocortin pathway has led to the use of melanocortin agonists to treat obesity derived from genetic disorders.
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Affiliation(s)
- Giulia Baldini
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Kevin D. Phelan
- Department of Neurobiology & Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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do Carmo JM, da Silva AA, Moak SP, Browning JR, Dai X, Hall JE. Increased sleep time and reduced energy expenditure contribute to obesity after ovariectomy and a high fat diet. Life Sci 2018; 212:119-128. [PMID: 30273560 PMCID: PMC6240909 DOI: 10.1016/j.lfs.2018.09.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/17/2018] [Accepted: 09/18/2018] [Indexed: 12/21/2022]
Abstract
In this study we examined if sleep time, caloric intake and energy expenditure are important contributors to development of ovariectomy-induced obesity in mice fed control or high fat diet (HFD). Twelve female mice at 6 weeks of age were divided into 2 groups: Sham (n = 5) and ovariectomized (OVX, n = 7). Mice were fed control diet for 9 weeks and shifted to HFD for additional 9 weeks. Food intake and body weight were measured daily and body composition was measured weekly by EchoMRI. Energy expenditure (EE), oxygen consumption (VO2), motor activity (MA) and sleep time were monitored at week 9 during control diet and HFD. OVX did not alter caloric intake, body weight or body composition, MA, sleep time or fasting blood glucose, but slightly reduced EE compared to Sham mice on control diet. After HFD feeding, OXV mice had similar caloric intake, lean mass, MA, and blood glucose levels but had significantly greater weight gain (8.2 ± 1.0 vs. 4.8 ± 1.2 g, p < 0.05), increased fat mass and sleep time, and reduced EE (3.3 ± 0.4 vs. 5.5 ± 0.2 kcal/h) and VO2 (1.12 ± 0.01 vs. 1.83 ± 0.05 ml/min) compared to Sham group. Daytime blood pressure was higher while nighttime heart rate was lower in OVX group. These results suggest that OVX may not substantially alter body weight or body composition in mice fed a normal diet, but when combined with HFD it increases sleep time and reduces EE, leading to greater weight gain and adiposity without altering food intake.
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Affiliation(s)
- Jussara M do Carmo
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States of America.
| | - Alexandre A da Silva
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Sydney P Moak
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Jackson R Browning
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Xuemei Dai
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - John E Hall
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, United States of America
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do Carmo JM, da Silva AA, Freeman JN, Wang Z, Moak SP, Hankins MW, Drummond HA, Hall JE. Neuronal Suppressor of Cytokine Signaling 3: Role in Modulating Chronic Metabolic and Cardiovascular Effects of Leptin. Hypertension 2018; 71:1248-1257. [PMID: 29686012 DOI: 10.1161/hypertensionaha.118.11127] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 03/06/2018] [Accepted: 03/19/2018] [Indexed: 12/21/2022]
Abstract
We determined whether deficiency of neuronal SOCS3 (suppressor of cytokine signaling 3)-a potential negative regulator of leptin signaling-amplifies the chronic effects of leptin on food intake, energy expenditure, glucose, and blood pressure (BP) and protects against adverse cardiometabolic effects of obesity. BP and heart rate were recorded by telemetry, and oxygen consumption (VO2) was monitored in 22-week-old mice with nervous system SOCS3 deficiency (SOCS3-Nestin-Cre) and control mice (SOCS3flox/flox) fed normal or high-fat-high-fructose diet from 6 to 22 weeks of age. Compared with controls, SOCS3-Nestin-Cre mice had lower plasma glucose (124±7 versus 146±10 mg/dL), consumed less food (3.0±0.4 versus 3.6±0.2 g/d), and had similar VO2 (77±6 versus 73±3 mL/kg per minute) and BP (103±3 versus 107±3 mm Hg) but higher heart rate (666±15 versus 602±17 bpm). In mice fed the normal diet, leptin infusion for 7 days caused similar reductions in food intake (2.3±0.1 versus 2.4±0.2 g) but greater increases in BP (15±3 versus 7±2 mm Hg) in SOCS3-Nestin-Cre compared with controls. Leptin reduced blood glucose concentrations in both groups. Male or female SOCS3-Nestin-Cre fed high-fat-high-fructose diet exhibited less weight gain, body fat, and liver steatosis and greater energy expenditure and heart rate compared with controls. Female SOCS3-Nestin-Cre mice fed high-fat-high-fructose diet had higher BP compared with controls. Thus, neuronal SOCS3 seems to play an important role in cardiometabolic regulation because neuronal SOCS3 deficiency reduced body weight and food intake while amplifying leptin's effects on appetite and BP and attenuating the adverse metabolic effects of high-fat-high-fructose diet.
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Affiliation(s)
- Jussara M do Carmo
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - Alexandre A da Silva
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.).,Faculdade de Medicina, Departamento de Fisiologia, Barão de Mauá University Center, Ribeirão Preto, São Paulo, Brazil (A.A.d.S.).,and Faculdade de Medicina, Departamento de Fisiologia, Universidade Estadual de Minas Gerais, Passos, Brazil (A.A.d.S.)
| | - John Nathan Freeman
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - Zhen Wang
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - Sydney P Moak
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - Michael W Hankins
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - Heather A Drummond
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
| | - John E Hall
- From the Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson (J.M.d.C., A.A.d.S., J.N.F., Z.W., S.P.M., M.W.H., H.A.D., J.E.H.)
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da Silva AA, Freeman JN, Hall JE, do Carmo JM. Control of appetite, blood glucose, and blood pressure during melanocortin-4 receptor activation in normoglycemic and diabetic NPY-deficient mice. Am J Physiol Regul Integr Comp Physiol 2017; 314:R533-R539. [PMID: 29351428 DOI: 10.1152/ajpregu.00293.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although central melanocortin 4 receptor (MC4R) blockade abolishes the central nervous system (CNS)-mediated anorexogenic, antidiabetic, and cardiovascular actions of leptin, chronic MC4R stimulation fails to completely mimic the effects of leptin. Because neuropeptide Y (NPY) and MC4R exert opposite effects on cardiovascular and metabolic functions, we tested the role of NPY in offsetting the long-term actions of MC4R activation. Wild-type (WT) and NPY-deficient (NPY-/-) mice were implanted with telemetry probes for measuring mean arterial pressure (MAP) and heart rate (HR) 24 h/day. After the mice recovered from surgery and stable baseline measurements, the MC3/4R agonist melanotan II (MTII, 120 μg·kg-1·day-1 iv) was infused for 7 days followed by a recovery period. No major differences between groups were observed at baseline except for slightly higher food intake and HR in NPY-/- mice (4.3 ± 0.2 vs. 3.4 ± 0.2 g/day and 567 ± 14 vs. 522 ± 13 beats/min). Chronic MTII infusion reduced food intake in both groups while causing transient increases in MAP and HR only in WT mice (peaks of 11 ± 3 mmHg and 126 ± 13 beats/min). To examine whether NPY deficiency would amplify the antidiabetic effects of MC4R activation, diabetes was induced with streptozotocin (STZ) 1 wk before baseline measurements were taken, and the same experimental protocol was followed. In WT and NPY-/- mice, STZ-induced diabetes led to similar hyperphagia, hyperglycemia, and weight loss, which were not reversed by chronic MTII treatment. Our results demonstrate that chronic MC4R activation, even in NPY-deficient mice, does not mimic chronic antidiabetic, cardiovascular, or metabolic actions of leptin, and that NPY is not essential for hyperphagia or cardiovascular changes associated with diabetes.
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Affiliation(s)
- 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, Sao Paulo , Brazil.,Universidade Estadual de Minas Gerais, Passos, Minas Gerais , Brazil
| | - J Nathan Freeman
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, 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
| | - 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
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Differential contribution of POMC and AgRP neurons to the regulation of regional autonomic nerve activity by leptin. Mol Metab 2017; 8:1-12. [PMID: 29289646 PMCID: PMC5985226 DOI: 10.1016/j.molmet.2017.12.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 11/30/2017] [Accepted: 12/12/2017] [Indexed: 02/06/2023] Open
Abstract
Objectives The autonomic nervous system is critically involved in mediating the control by leptin of many physiological processes. Here, we examined the role of the leptin receptor (LepR) in proopiomelanocortin (POMC) and agouti-related peptide (AgRP) neurons in mediating the effects of leptin on regional sympathetic and parasympathetic nerve activity. Methods We analyzed how deletion of the LepR in POMC neurons (POMCCre/LepRfl/fl mice) or AgRP neurons (AgRPCre/LepRfl/fl mice) affects the ability of leptin to increase sympathetic and parasympathetic nerve activity. We also studied mice lacking the catalytic p110α or p110β subunits of phosphatidylinositol-3 kinase (PI3K) in POMC neurons. Results Leptin-evoked increase in sympathetic nerve activity subserving thermogenic brown adipose tissue was partially blunted in mice lacking the LepR in either POMC or AgRP neurons. On the other hand, loss of the LepR in AgRP, but not POMC, neurons interfered with leptin-induced sympathetic nerve activation to the inguinal fat depot. The increase in hepatic sympathetic traffic induced by leptin was also reduced in mice lacking the LepR in AgRP, but not POMC, neurons whereas LepR deletion in either AgRP or POMC neurons attenuated the hepatic parasympathetic nerve activation evoked by leptin. Interestingly, the renal, lumbar and splanchnic sympathetic nerve activation caused by leptin were significantly blunted in POMCCre/LepRfl/fl mice, but not in AgRPCre/LepRfl/fl mice. However, loss of the LepR in POMC or AgRP neurons did not interfere with the ability of leptin to increase sympathetic traffic to the adrenal gland. Furthermore, ablation of the p110α, but not the p110β, isoform of PI3K from POMC neurons eliminated the leptin-elicited renal sympathetic nerve activation. Finally, we show trans-synaptic retrograde tracing of both POMC and AgRP neurons from the kidneys. Conclusions POMC and AgRP neurons are differentially involved in mediating the effects of leptin on autonomic nerve activity subserving various tissues and organs. Both POMC and AgRP neurons contribute to leptin-elicited increase in BAT SNA and hepatic PSNA. AgRP neurons mediate leptin-evoked increase in SNA subserving WAT and liver. Leptin-induced increase in lumbar, splanchnic and renal SNA is mediated by POMC neurons. The p110α, but not p110β, subunit of PI3K in POMC neurons is required for the effect of leptin on renal SNA.
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Dodd GT, Tiganis T. Insulin action in the brain: Roles in energy and glucose homeostasis. J Neuroendocrinol 2017; 29. [PMID: 28758251 DOI: 10.1111/jne.12513] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/05/2017] [Accepted: 07/26/2017] [Indexed: 12/14/2022]
Abstract
A growing body of evidence from research in rodents and humans has identified insulin as an important neuoregulatory peptide in the brain, where it coordinates diverse aspects of energy balance and peripheral glucose homeostasis. This review discusses where and how insulin interacts within the brain and evaluates the physiological and pathophysiological consequences of central insulin signalling in metabolism, obesity and type 2 diabetes.
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Affiliation(s)
- G T Dodd
- Metabolic Disease and Obesity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
| | - T Tiganis
- Metabolic Disease and Obesity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC, Australia
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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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17
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Stocker SD, Kinsman BJ, Sved AF. Recent Advances in Neurogenic Hypertension: Dietary Salt, Obesity, and Inflammation. Hypertension 2017; 70:HYPERTENSIONAHA.117.08936. [PMID: 28739972 PMCID: PMC5783795 DOI: 10.1161/hypertensionaha.117.08936] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Neurally-mediated hypertension results from a dysregulation of sympathetic and/or neuroendocrine mechanisms to increase ABP. Multiple factors may exert multiple central effects to alter neural circuits and produce unique sympathetic signatures and elevate ABP. In this brief review, we have discussed novel observations regarding three contributing factors: dietary salt intake, obesity, and inflammation. However, the interaction among these and other factors is likely much more complex; recent studies suggest a prior exposure to one stimulus may sensitize the response to a subsequent hypertensive stimulus. Insight into the central mechanisms by which these factors selectively alter SNA or cooperatively interact to impact hypertension may represent a platform for novel therapeutic treatment strategies.
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Affiliation(s)
- Sean D Stocker
- From the Department of Medicine, Renal-Electrolyte Division (S.D.S., B.J.K.), Department of Neuroscience (A.F.S.), and University of Pittsburgh Hypertension Center (S.D.S.), University of Pittsburgh, PA.
| | - Brian J Kinsman
- From the Department of Medicine, Renal-Electrolyte Division (S.D.S., B.J.K.), Department of Neuroscience (A.F.S.), and University of Pittsburgh Hypertension Center (S.D.S.), University of Pittsburgh, PA
| | - Alan F Sved
- From the Department of Medicine, Renal-Electrolyte Division (S.D.S., B.J.K.), Department of Neuroscience (A.F.S.), and University of Pittsburgh Hypertension Center (S.D.S.), University of Pittsburgh, PA
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da Silva AA, Hall JE, Moak SP, Browning J, Houghton HJ, Micheloni GC, do Carmo JM. Role of autonomic nervous system in chronic CNS-mediated antidiabetic action of leptin. Am J Physiol Endocrinol Metab 2017; 312:E420-E428. [PMID: 27923809 PMCID: PMC5451526 DOI: 10.1152/ajpendo.00301.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 12/02/2016] [Accepted: 12/02/2016] [Indexed: 01/13/2023]
Abstract
This study tested whether ganglionic blockade or hepatic vagotomy attenuates the chronic central nervous system (CNS)-mediated antidiabetic and cardiovascular effects of leptin. Male Sprague-Dawley rats were instrumented with telemetry probes and arterial and venous catheters for determination of blood pressure (BP), heart rate (HR), blood sampling, and intravenous (iv) infusions. An intracerebroventricular (ICV) cannula was placed into the brain lateral ventricle for infusion of leptin or vehicle. After control measurements, streptozotocin (STZ) was injected iv (50 mg/kg) to induce diabetes, and 5 days later leptin (n = 6) or saline vehicle (n = 5) was infused ICV for 12 days via osmotic pumps. Beginning on day 6 of leptin treatment, the ganglionic blocker hexamethonium (15 mg·kg-1·day-1 iv) was infused, while leptin infusion was continued, to assess the role of the autonomic nervous system. Induction of diabetes was associated with increases in blood glucose (98 ± 7 to 350 ± 19 mg/dl), food intake (23 ± 3 to 43 ± 3 g/day), decreases in HR (-70 ± 11 beats/min), polyuria, and increased water consumption, which were all completely normalized by ICV leptin infusion. Although hexamethonium attenuated leptin's effect on HR, it failed to impair leptin's ability to restore euglycemia or to prevent the polyuria or increased water intake in STZ-diabetic rats. We also found that after pretreatment with hexamethonium (n = 8), ICV leptin infusion, during continued ganglionic blockade, completely normalized blood glucose in diabetic rats. In addition, selective hepatic vagotomy did not attenuate leptin's ability to restore euglycemia in diabetic rats. These results suggest that leptin's powerful chronic CNS antidiabetic actions are mediated primarily via nonautonomic mechanisms.
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Affiliation(s)
- 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; and
- Barão de Mauá University Center, Ribeirão Preto, São Paulo, Brazil
| | - John E Hall
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi; and
| | - Sydney P Moak
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi; and
| | - Jackson Browning
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi; and
| | - Haley J Houghton
- Department of Physiology and Biophysics, Mississippi Center for Obesity Research, Cardiovascular-Renal Research Center, University of Mississippi Medical Center, Jackson, Mississippi; and
| | | | - 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; and
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Dorfman MD, Krull JE, Scarlett JM, Guyenet SJ, Sajan MP, Damian V, Nguyen HT, Leitges M, Morton GJ, Farese RV, Schwartz MW, Thaler JP. Deletion of Protein Kinase C λ in POMC Neurons Predisposes to Diet-Induced Obesity. Diabetes 2017; 66:920-934. [PMID: 28073831 PMCID: PMC5360303 DOI: 10.2337/db16-0482] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 01/02/2017] [Indexed: 12/16/2022]
Abstract
Effectors of the phosphoinositide 3-kinase (PI3K) signal transduction pathway contribute to the hypothalamic regulation of energy and glucose homeostasis in divergent ways. Here we show that central nervous system (CNS) action of the PI3K signaling intermediate atypical protein kinase C (aPKC) constrains food intake, weight gain, and glucose intolerance in both rats and mice. Pharmacological inhibition of CNS aPKC activity acutely increases food intake and worsens glucose tolerance in chow-fed rodents and causes excess weight gain during high-fat diet (HFD) feeding. Similarly, selective deletion of the aPKC isoform Pkc-λ in proopiomelanocortin (POMC) neurons disrupts leptin action, reduces melanocortin content in the paraventricular nucleus, and markedly increases susceptibility to obesity, glucose intolerance, and insulin resistance specifically in HFD-fed male mice. These data implicate aPKC as a novel regulator of energy and glucose homeostasis downstream of the leptin-PI3K pathway in POMC neurons.
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Affiliation(s)
- Mauricio D Dorfman
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, WA
| | - Jordan E Krull
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, WA
| | - Jarrad M Scarlett
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, WA
| | - Stephan J Guyenet
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, WA
| | - Mini P Sajan
- Department of Internal Medicine, University of South Florida College of Medicine, Tampa, FL
- Research & Internal Medicine Services, James A. Haley VA Medical Center, Tampa, FL
| | - Vincent Damian
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, WA
| | - Hong T Nguyen
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, WA
| | - Michael Leitges
- The Biotechnology Centre of Oslo, University of Oslo, Oslo, Norway
| | - Gregory J Morton
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, WA
| | - Robert V Farese
- Department of Internal Medicine, University of South Florida College of Medicine, Tampa, FL
- Research & Internal Medicine Services, James A. Haley VA Medical Center, Tampa, FL
| | - Michael W Schwartz
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, WA
| | - Joshua P Thaler
- UW Diabetes Institute and Department of Medicine, University of Washington, Seattle, WA
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20
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DNA methylation and histone deacetylation regulating insulin sensitivity due to chronic cold exposure. Cryobiology 2017; 74:36-42. [DOI: 10.1016/j.cryobiol.2016.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 11/01/2016] [Accepted: 12/13/2016] [Indexed: 11/18/2022]
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Affiliation(s)
- Maik Gollasch
- Medical Clinic for Nephrology and Internal Intensive Care, Charité Campus Virchow Klinikum, and Experimental and Clinical Research Center, a joint cooperation of the Charité – University Medicine Berlin and Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany;
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22
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Hill JW, Faulkner LD. The Role of the Melanocortin System in Metabolic Disease: New Developments and Advances. Neuroendocrinology 2017; 104:330-346. [PMID: 27728914 PMCID: PMC5724371 DOI: 10.1159/000450649] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/01/2016] [Indexed: 12/17/2022]
Abstract
Obesity is increasing in prevalence across all sectors of society, and with it a constellation of associated ailments including hypertension, type 2 diabetes, and eating disorders. The melanocortin system is a critical neural system underlying the control of body weight and other functions. Deficits in the melanocortin system may promote or exacerbate the comorbidities of obesity. This system has therefore generated great interest as a potential target for treatment of obesity. However, drugs targeting melanocortin receptors are plagued by problematic side effects, including undesirable increases in sympathetic nervous system activity, heart rate, and blood pressure. Circumnavigating this roadblock will require a clearer picture of the precise neural circuits that mediate the functions of melanocortins. Recent, novel experimental approaches have significantly advanced our understanding of these pathways. We here review the latest advances in our understanding of the role of melanocortins in food intake, reward pathways, blood pressure, glucose control, and energy expenditure. The evidence suggests that downstream melanocortin-responsive circuits responsible for different physiological actions do diverge. Ultimately, a more complete understanding of melanocortin pathways and their myriad roles should allow treatments tailored to the mix of metabolic disorders in the individual patient.
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Affiliation(s)
- Jennifer W Hill
- Department of Physiology and Pharmacology, College of Medicine, The University of Toledo, Toledo, OH, USA
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Parto P, Lavie CJ, Arena R, Bond S, Popovic D, Ventura HO. Body habitus in heart failure: understanding the mechanisms and clinical significance of the obesity paradox. Future Cardiol 2016; 12:639-653. [DOI: 10.2217/fca-2016-0029] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The prevalence of obesity among adults and children worldwide has reached epic proportions and has become a major independent risk factor for the development of heart failure (HF), in addition to a contributor of hypertension and cardiovascular disease. The implications of obesity in the development of HF involve adverse effects on cardiac structure and function. Despite all of this, in the setting of chronic HF, excess body mass is associated with improved clinical outcomes, demonstrating the presence of an obesity paradox. In this review, we will discuss the gender differences, global application, potential mechanisms and role of interventions based on fitness and purposeful weight loss as potential therapeutic strategies.
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Affiliation(s)
- Parham Parto
- Department of Cardiovascular Diseases, John Ochsner Heart & Vascular Institute, Ochsner Clinical School-University of Queensland School of Medicine, 1514 Jefferson Highway, New Orleans, LA 70121, USA
| | - Carl J Lavie
- Department of Cardiovascular Diseases, John Ochsner Heart & Vascular Institute, Ochsner Clinical School-University of Queensland School of Medicine, 1514 Jefferson Highway, New Orleans, LA 70121, USA
| | - Ross Arena
- Department of Physical Therapy, Department of Kinesiology & Nutrition & Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Samantha Bond
- Department of Biomedical & Health Information Sciences, College of Applied Science, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Dejana Popovic
- Clinic for Cardiology, University Clinical Center Serbia, Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia
| | - Hector O Ventura
- Department of Cardiovascular Diseases, John Ochsner Heart & Vascular Institute, Ochsner Clinical School-University of Queensland School of Medicine, 1514 Jefferson Highway, New Orleans, LA 70121, USA
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