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McFarlin BE, Duffin KL, Konkar A. Incretin and glucagon receptor polypharmacology in chronic kidney disease. Am J Physiol Endocrinol Metab 2024; 326:E747-E766. [PMID: 38477666 DOI: 10.1152/ajpendo.00374.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/10/2024] [Indexed: 03/14/2024]
Abstract
Chronic kidney disease is a debilitating condition associated with significant morbidity and mortality. In recent years, the kidney effects of incretin-based therapies, particularly glucagon-like peptide-1 receptor agonists (GLP-1RAs), have garnered substantial interest in the management of type 2 diabetes and obesity. This review delves into the intricate interactions between the kidney, GLP-1RAs, and glucagon, shedding light on their mechanisms of action and potential kidney benefits. Both GLP-1 and glucagon, known for their opposing roles in regulating glucose homeostasis, improve systemic risk factors affecting the kidney, including adiposity, inflammation, oxidative stress, and endothelial function. Additionally, these hormones and their pharmaceutical mimetics may have a direct impact on the kidney. Clinical studies have provided evidence that incretins, including those incorporating glucagon receptor agonism, are likely to exhibit improved kidney outcomes. Although further research is necessary, receptor polypharmacology holds promise for preserving kidney function through eliciting vasodilatory effects, influencing volume and electrolyte handling, and improving systemic risk factors.
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Affiliation(s)
- Brandon E McFarlin
- Lilly Research Laboratories, Lilly Corporate CenterIndianapolisIndianaUnited States
| | - Kevin L Duffin
- Lilly Research Laboratories, Lilly Corporate CenterIndianapolisIndianaUnited States
| | - Anish Konkar
- Lilly Research Laboratories, Lilly Corporate CenterIndianapolisIndianaUnited States
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2
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Zhang Y, Chen S, Luo L, Greenly S, Shi H, Xu JJ, Yan C. Role of cAMP in Cardiomyocyte Viability: Beneficial or Detrimental? Circ Res 2023; 133:902-923. [PMID: 37850368 PMCID: PMC10807647 DOI: 10.1161/circresaha.123.322652] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 10/10/2023] [Indexed: 10/19/2023]
Abstract
BACKGROUND 3', 5'-cyclic AMP (cAMP) regulates numerous cardiac functions. Various hormones and neurotransmitters elevate intracellular cAMP (i[cAMP]) in cardiomyocytes through activating GsPCRs (stimulatory-G-protein-coupled-receptors) and membrane-bound ACs (adenylyl cyclases). Increasing evidence has indicated that stimulating different GsPCRs and ACs exhibits distinct, even opposite effects, on cardiomyocyte viability. However, the underlying mechanisms are not fully understood. METHODS We used molecular and pharmacological approaches to investigate how different GsPCR/cAMP signaling differentially regulate cardiomyocyte viability with in vitro, ex vivo, and in vivo models. RESULTS For prodeath GsPCRs, we explored β1AR (beta1-adrenergic receptor) and H2R (histamine-H2-receptor). We found that their prodeath effects were similarly dependent on AC5 activation, ATP release to the extracellular space via PANX1 (pannexin-1) channel, and extracellular ATP (e[ATP])-mediated signaling involving in P2X7R (P2X purinoceptor 7) and CaMKII (Ca2+/calmodulin-dependent protein kinase II). PANX1 phosphorylation at Serine 206 by cAMP-dependent-PKA (protein-kinase-A) promoted PANX1 activation, which was critical in β1AR- or H2R-induced cardiomyocyte death in vitro and in vivo. β1AR or H2R was localized proximately to PANX1, which permits ATP release. For prosurvival GsPCRs, we explored adenosine-A2-receptor (A2R), CGRPR (calcitonin-gene-related-peptide-receptor), and RXFP1 (relaxin-family peptide-receptor 1). Their prosurvival effects were dependent on AC6 activation, cAMP efflux via MRP4 (multidrug resistance protein 4), extracellular cAMP metabolism to adenosine (e[cAMP]-to-e[ADO]), and e[ADO]-mediated signaling. A2R, CGRPR, or RXFP1 was localized proximately to MRP4, which enables cAMP efflux. Interestingly, exogenously increasing e[cAMP] levels by membrane-impermeable cAMP protected against cardiomyocyte death in vitro and in ex vivo and in vivo mouse hearts with ischemia-reperfusion injuries. CONCLUSIONS Our findings indicate that the functional diversity of different GsPCRs in cardiomyocyte viability could be achieved by their ability to form unique signaling complexes (signalosomes) that determine the fate of cAMP: either stimulate ATP release by activating PKA or directly efflux to be e[cAMP].
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Affiliation(s)
- Yishuai Zhang
- Aab Cardiovascular Research Institute, Department of Medicine
| | - Si Chen
- Aab Cardiovascular Research Institute, Department of Medicine
| | - Lingfeng Luo
- Aab Cardiovascular Research Institute, Department of Medicine
- Department of Biochemistry and Biophysics
| | - Sarah Greenly
- Aab Cardiovascular Research Institute, Department of Medicine
| | - Hangchuan Shi
- Department of Clinical and Translational Research
- Department of Public Health Sciences; University of Rochester School of Medicine and Dentistry, Rochester, NY 14642
| | | | - Chen Yan
- Aab Cardiovascular Research Institute, Department of Medicine
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González-Velasco Ó, De Las Rivas J, Lacal J. Proteomic and Transcriptomic Profiling Identifies Early Developmentally Regulated Proteins in Dictyostelium Discoideum. Cells 2019; 8:cells8101187. [PMID: 31581556 PMCID: PMC6830349 DOI: 10.3390/cells8101187] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 09/26/2019] [Indexed: 02/06/2023] Open
Abstract
Cyclic AMP acts as a secondary messenger involving different cellular functions in eukaryotes. Here, proteomic and transcriptomic profiling has been combined to identify novel early developmentally regulated proteins in eukaryote cells. These proteomic and transcriptomic experiments were performed in Dictyostelium discoideum given the unique advantages that this organism offers as a eukaryotic model for cell motility and as a nonmammalian model of human disease. By comparing whole-cell proteome analysis of developed (cAMP-pulsed) wild-type AX2 cells and an independent transcriptomic analysis of developed wild-type AX4 cells, our results show that up to 70% of the identified proteins overlap in the two independent studies. Among them, we have found 26 proteins previously related to cAMP signaling and identified 110 novel proteins involved in calcium signaling, adhesion, actin cytoskeleton, the ubiquitin-proteasome pathway, metabolism, and proteins that previously lacked any annotation. Our study validates previous findings, mostly for the canonical cAMP-pathway, and also generates further insight into the complexity of the transcriptomic changes during early development. This article also compares proteomic data between parental and cells lacking glkA, a GSK-3 kinase implicated in substrate adhesion and chemotaxis in Dictyostelium. This analysis reveals a set of proteins that show differences in expression in the two strains as well as overlapping protein level changes independent of GlkA.
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Affiliation(s)
- Óscar González-Velasco
- Bioinformatics and Functional Genomics Research Group. Cancer Research Center (CIC-IBMCC, CSIC/USAL/IBSAL), 37007 Salamanca, Spain.
| | - Javier De Las Rivas
- Bioinformatics and Functional Genomics Research Group. Cancer Research Center (CIC-IBMCC, CSIC/USAL/IBSAL), 37007 Salamanca, Spain.
| | - Jesus Lacal
- Department of Microbiology and Genetics, Faculty of Biology, University of Salamanca, 37007 Salamanca, Spain.
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Badillo P, Salgado P, Bravo P, Guevara K, Acurio J, Gonzalez MA, Oyarzun C, San Martin R, Escudero C. High plasma adenosine levels in overweight/obese pregnant women. Purinergic Signal 2017; 13:479-488. [PMID: 28721552 PMCID: PMC5714837 DOI: 10.1007/s11302-017-9574-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 07/06/2017] [Indexed: 10/19/2022] Open
Abstract
We aim to investigate whether overweight/obese pregnant women have elevated plasma levels of adenosine associated with increased consumption of high-calorie food. Sixty women were included. They were divided into lean (n = 23 and n = 12) or overweight/obese (n = 7 and n = 18) non-pregnant and pregnant women, respectively. Clinical records and maternal blood samples were collected after informed consent. A self-reported dietary questionnaire was also completed. Plasma adenosine levels were determined with high-performance liquid chromatography. Biochemical parameters, including glucose, total protein, and lipid profile, were determined using standard colorimetric assays. Adenosine levels were higher in pregnant women than in non-pregnant women (18.7 ± 1.6 vs 10.8 ± 1.3 nM/μg protein, respectively, p < 0.0001). Overweight/obese pregnant women (21.9 ± 2.5 nM/μg protein) exhibited higher adenosine levels than lean pregnant (14.5 ± 1.0 nM/μg protein, p = 0.04) or non-pregnant women (11.7 ± 1.5 nM/μg protein, p = 0.0005). Also, pregnant women with elevated weight gain exhibited higher (26.2 ± 3.7 nM/μg protein) adenosine levels than those with adequate weight gain (14.9 ± 1.4 nM/μg protein, p = 0.03). These differences were not statistically significant compared with those of pregnant women with reduced weight gain (17.4 ± 2.1 nM/μg protein, p = 0.053). Body mass index and adenosine only in pregnant women were positively correlated (r = 0.39, p = 0.02). While, polyunsaturated fatty acid (PUFA) consumption was negatively correlated with plasma adenosine levels only in non-pregnant women (r = -0.33, p = 0.03). Pregnancy is associated with high plasma adenosine levels, which are further elevated in pregnant women who are overweight/obese. High PUFA intake might reduce plasma adenosine levels in non-pregnant women.
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Affiliation(s)
- Priscila Badillo
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (LFV-GIANT), University of Bío-Bío, Chillán, Chile
| | - Paola Salgado
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (LFV-GIANT), University of Bío-Bío, Chillán, Chile
| | - Patricia Bravo
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (LFV-GIANT), University of Bío-Bío, Chillán, Chile
| | - Katherine Guevara
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (LFV-GIANT), University of Bío-Bío, Chillán, Chile
| | - Jesenia Acurio
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (LFV-GIANT), University of Bío-Bío, Chillán, Chile
- Group of Research and Innovation in Vascular Health (GRIVAS Health), University of Bío-Bío, Chillán, Chile
- Department of Basic Sciences, University of Bío-Bío, Chillán, Chile
| | - Maria Angelica Gonzalez
- Department of Nutrition, Health and Food Sciences Faculty, University of Bío-Bío, Chillán, Chile
| | - Carlos Oyarzun
- Laboratorio de Patologia Molecular, Instituto de Bioquimica y Microbiologia, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja, P.O. Box 567, Valdivia, Chile
| | - Rody San Martin
- Laboratorio de Patologia Molecular, Instituto de Bioquimica y Microbiologia, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja, P.O. Box 567, Valdivia, Chile
| | - Carlos Escudero
- Vascular Physiology Laboratory, Group of Investigation in Tumor Angiogenesis (LFV-GIANT), University of Bío-Bío, Chillán, Chile.
- Group of Research and Innovation in Vascular Health (GRIVAS Health), University of Bío-Bío, Chillán, Chile.
- Department of Basic Sciences, University of Bío-Bío, Chillán, Chile.
- Department of Nutrition, Health and Food Sciences Faculty, University of Bío-Bío, Chillán, Chile.
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Lv S, Qiu X, Li J, Liang J, Li W, Zhang C, Zhang ZN, Luan B. Glucagon-induced extracellular cAMP regulates hepatic lipid metabolism. J Endocrinol 2017; 234:73-87. [PMID: 28515141 DOI: 10.1530/joe-16-0649] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 01/07/2023]
Abstract
Hormonal signals help to maintain glucose and lipid homeostasis in the liver during the periods of fasting. Glucagon, a pancreas-derived hormone induced by fasting, promotes gluconeogenesis through induction of intracellular cAMP production. Glucagon also stimulates hepatic fatty acid oxidation but the underlying mechanism is poorly characterized. Here we report that following the acute induction of gluconeogenic genes Glucose 6 phosphatase (G6Pase) and Phosphoenolpyruvate carboxykinase (Pepck) expression through cAMP-response element-binding protein (CREB), glucagon triggers a second delayed phase of fatty acid oxidation genes Acyl-coenzyme A oxidase (Aox) and Carnitine palmitoyltransferase 1a (Cpt1a) expression via extracellular cAMP. Increase in extracellular cAMP promotes PPARα activity through direct phosphorylation by AMP-activated protein kinase (AMPK), while inhibition of cAMP efflux greatly attenuates Aox and Cpt1a expression. Importantly, cAMP injection improves lipid homeostasis in fasted mice and obese mice, while inhibition of cAMP efflux deteriorates hepatic steatosis in fasted mice. Collectively, our results demonstrate the vital role of glucagon-stimulated extracellular cAMP in the regulation of hepatic lipid metabolism through AMPK-mediated PPARα activation. Therefore, strategies to improve cAMP efflux could serve as potential new tools to prevent obesity-associated hepatic steatosis.
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Affiliation(s)
- Sihan Lv
- Department of EndocrinologyShanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Xinchen Qiu
- Department of EndocrinologyShanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jian Li
- Department of EndocrinologyShanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jinye Liang
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Weida Li
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Chao Zhang
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zhen-Ning Zhang
- Translational Medical Center for Stem Cell Therapy & Institute for Regenerative MedicineShanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Bing Luan
- Department of EndocrinologyShanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China
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Godinho RO, Duarte T, Pacini ESA. New perspectives in signaling mediated by receptors coupled to stimulatory G protein: the emerging significance of cAMP efflux and extracellular cAMP-adenosine pathway. Front Pharmacol 2015; 6:58. [PMID: 25859216 PMCID: PMC4373373 DOI: 10.3389/fphar.2015.00058] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 03/06/2015] [Indexed: 12/25/2022] Open
Abstract
G protein-coupled receptors (GPCRs) linked to stimulatory G (Gs) proteins (GsPCRs) mediate increases in intracellular cyclic AMP as consequence of activation of nine adenylyl cyclases , which differ considerably in their cellular distribution and activation mechanisms. Once produced, cyclic AMP may act via distinct intracellular signaling effectors such as protein kinase A and the exchange proteins activated by cAMP (Epacs). More recently, attention has been focused on the efflux of cAMP through a specific transport system named multidrug resistance proteins that belongs to the ATP-binding cassette transporter superfamily. Outside the cell, cAMP is metabolized into adenosine, which is able to activate four distinct subtypes of adenosine receptors, members of the GPCR family: A1, A2A, A2B, and A3. Taking into account that this phenomenon occurs in numerous cell types, as consequence of GsPCR activation and increment in intracellular cAMP levels, in this review, we will discuss the impact of cAMP efflux and the extracellular cAMP-adenosine pathway on the regulation of GsPCR-induced cell response.
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Affiliation(s)
- Rosely O Godinho
- Disciplina Farmacologia Celular, Departamento de Farmacologia, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
| | - Thiago Duarte
- Disciplina Farmacologia Celular, Departamento de Farmacologia, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
| | - Enio S A Pacini
- Disciplina Farmacologia Celular, Departamento de Farmacologia, Escola Paulista de Medicina, Universidade Federal de São Paulo São Paulo, Brazil
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Sciaraffia E, Riccomi A, Lindstedt R, Gesa V, Cirelli E, Patrizio M, De Magistris MT, Vendetti S. Human monocytes respond to extracellular cAMP through A2A and A2B adenosine receptors. J Leukoc Biol 2014; 96:113-22. [PMID: 24652540 DOI: 10.1189/jlb.3a0513-302rr] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In this study, we test the hypothesis that cAMP, acting as an extracellular mediator, affects the physiology and function of human myeloid cells. The cAMP is a second messenger recognized as a universal regulator of several cellular functions in different organisms. Many studies have shown that extracellular cAMP exerts regulatory functions, acting as first mediator in multiple tissues. However, the impact of extracellular cAMP on cells of the immune system has not been fully investigated. We found that human monocytes exposed to extracellular cAMP exhibit higher expression of CD14 and lower amount of MHC class I and class II molecules. When cAMP-treated monocytes are exposed to proinflammatory stimuli, they exhibit an increased production of IL-6 and IL-10 and a lower amount of TNF-α and IL-12 compared with control cells, resembling the features of the alternative-activated macrophages or M2 macrophages. In addition, we show that extracellular cAMP affects monocyte differentiation into DCs, promoting the induction of cells displaying an activated, macrophage-like phenotype with reduced capacity of polarized, naive CD4(+) T cells into IFN-γ-producing lymphocytes compared with control cells. The effects of extracellular cAMP on monocytes are mediated by CD73 ecto-5'-nucleotidase and A2A and A2B adenosine receptors, as selective antagonists could reverse its effects. Of note, the expression of CD73 molecules has been found on the membrane of a small population of CD14(+)CD16(+) monocytes. These findings suggest that an extracellular cAMP-adenosine pathway is active in cells of the immune systems.
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Affiliation(s)
- Ester Sciaraffia
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and
| | - Antonella Riccomi
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and
| | - Ragnar Lindstedt
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and
| | - Valentina Gesa
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and
| | - Elisa Cirelli
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and Animal Breeding Department, University of Rome "Tor Vergata", Rome, Italy
| | - Mario Patrizio
- Department of Drug Research and Evaluation, Istituto Superiore di Sanità, Rome, Italy; and
| | | | - Silvia Vendetti
- Department of Infectious, Parasitic and Immune-Mediated Diseases, and
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Cheng D, Zhu X, Gillespie DG, Jackson EK. Role of RACK1 in the differential proliferative effects of neuropeptide Y(1-36) and peptide YY(1-36) in SHR vs. WKY preglomerular vascular smooth muscle cells. Am J Physiol Renal Physiol 2013; 304:F770-80. [PMID: 23303411 DOI: 10.1152/ajprenal.00646.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Previous studies show that neuropeptide Y(1-36) (NPY(1-36)) and peptide YY(1-36) (PYY(1-36)), by engaging Y1 receptors, stimulate proliferation of spontaneous hypertensive rat (SHR) preglomerular vascular smooth muscle cells (PGVSMCs). In contrast, these peptides have little effect on proliferation of Wistar-Kyoto (WKY) PGVSMCs. Why SHR and WKY PGVSMCs differ in this regard is unknown. Because receptor for activated C kinase 1 (RACK1) can modulate cell proliferation, we tested the hypothesis that differences in RACK1 levels/localization may explain the differential response of SHR vs. WKY PGVSMCs to NPY(1-36) and PYY(1-36). Western blotting for RACK1 in subcellular fractions of cultured SHR and WKY PGVSMCs demonstrated increased levels of RACK1 in the membrane and cytoskeletal subcellular fractions of SHR vs. WKY PGVSMCs. NPY(1-36) and PYY(1-36) stimulated proliferation of SHR PGVSMCs, and siRNA knockdown of RACK1 abrogated this effect. Neither NPY(1-36) nor PYY(1-36) stimulated the proliferation of WKY PGVSMCs. However, in WKY PGVSMCs treated with a RACK1 plasmid, both NPY(1-36) and PYY(1-36) stimulated proliferation. In SHR PGVSMCs, inhibitors of the G(i)/phospholipase C/PKC pathway (a pathway known to be organized by RACK1) attenuated the ability of NPY(1-36) to stimulate the proliferation of SHR PGVSMCs. Our results suggest that RACK1 modulates the ability of PGVSMCs to respond to the proliferative actions of NPY(1-36) and PYY(1-36)and differences in RACK1 levels/localization account for, in part, differential proliferative responses to NPY(1-36) and PYY(1-36) in SHR vs. WKY PGVSMCs. Because dipeptidyl peptidase IV inhibitors increase NPY(1-36) and PYY(1-36) levels, our findings have implications for the use of such drugs in diabetic patients.
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Affiliation(s)
- Dongmei Cheng
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
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Escudero A, Carreño B, Retamal N, Celis C, Castro L, Aguayo C, Acurio J, Escudero C. Elevated concentrations of plasma adenosine in obese children. Biofactors 2012; 38:422-8. [PMID: 22890589 DOI: 10.1002/biof.1039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 07/01/2012] [Accepted: 07/18/2012] [Indexed: 01/19/2023]
Abstract
There are no data regarding adenosine levels in obese children, even though is a ubiquitous molecule implicated in the regulation of lipid metabolism in humans. To determinate whether adenosine plasma levels are related with anthropometric and biochemical markers in children, we studied 51 students belong to Ramon Belmar School in Linares, Chile. Review of clinical data and frequent food questionnaire were taken in order to collect the information. Plasma adenosine levels were measured by high-performance liquid chromatography and biochemical parameters including insulin, glucose, total proteins, and lipid profile by using standard colorimetric assays. Children with detectable (above 0.1 μM) adenosine plasma levels (n = 30; BMI, 22.3 ± 0.7) had higher total cholesterol (P < 0.05); triglycerides (P < 0.01) and LDL-cholesterol (P < 0.05) concentrations than children with undetectable adenosine levels (n = 21; BMI, 23.9 ± 0.61). Among the analyzed variables, only BMI and BMI standard deviation score (BMI-SDS) were positively correlated with adenosine levels. Besides, obese children (n = 10) showed significantly high adenosine levels compared to controls (n = 11; 1.8 ± 0.2 vs. 1.2 ± 0.1 μM/mg protein, respectively. P < 0.05), but not compared to overweight children (n = 9). In conclusion, obesity in children is associated to high adenosine plasma levels. This study opens a new perspective to investigate the role of adenosine in the regulation of lipid metabolism in obese children.
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Affiliation(s)
- Andrea Escudero
- Vascular Physiology Laboratory, Department of Basic Sciences, University of Bío-Bío, Chillán, Chile
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10
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Duarte T, Menezes-Rodrigues FS, Godinho RO. Contribution of the extracellular cAMP-adenosine pathway to dual coupling of β2-adrenoceptors to Gs and Gi proteins in mouse skeletal muscle. J Pharmacol Exp Ther 2012; 341:820-8. [PMID: 22438472 DOI: 10.1124/jpet.112.192997] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
β(2)-Adrenoceptor (β(2)-AR) agonists increase skeletal muscle contractile force via activation of G(s) protein/adenylyl cyclases (AC) and increased generation of cAMP. Herein, we evaluated the possible dual coupling of β(2)-AR to G(s) and G(i) proteins and the influence of the β(2)-AR/G(s)-G(i)/cAMP signaling cascade on skeletal muscle contraction. Assuming that the increment of intracellular cAMP is followed by cAMP efflux and extracellular generation of adenosine, the contribution of the extracellular cAMP-adenosine pathway on the β(2)-AR inotropic response was also addressed. The effects of clenbuterol/fenoterol (β(2)-AR agonists), forskolin (AC activator), cAMP/8-bromo-cAMP, and adenosine were evaluated on isometric contractility of mouse diaphragm muscle induced by supramaximal direct electrical stimulation (0.1 Hz, 2 ms duration). Clenbuterol/fenoterol (10-1000 μM), 1 μM forskolin, and 20 μM rolipram induced transient positive inotropic effects that peaked 30 min after stimulation onset, declining to 10 to 20% of peak levels in 30 min. The late descending phase of the β(2)-AR agonist inotropic effect was mimicked by either cAMP or adenosine and abolished by preincubation of diaphragm with pertussis toxin (PTX) (G(i) signaling inhibitor) or the organic anion transporter inhibitor probenecid, indicating a delayed coupling of β(2)-AR to G(i) protein which depends on cAMP efflux. Remarkably, the PTX-sensitive β(2)-AR inotropic effect was inhibited by the A(1) adenosine receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine and ecto-5'-phosphodiesterase inhibitor α,β-methyleneadenosine 5'-diphosphate sodium salt, indicating that β(2)-AR coupling to G(i) is indirect and dependent on A(1) receptor activation. The involvement of the extracellular cAMP-adenosine pathway in β(2)-AR signaling would provide a negative feedback loop that may limit stimulatory G protein-coupled receptor positive inotropism and potential deleterious effects of excessive contractile response.
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Affiliation(s)
- Thiago Duarte
- Division of Cellular Pharmacology, Department of Pharmacology, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio, 100 São Paulo, SP Brazil 04044-020
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Hofer AM, Lefkimmiatis K. Extracellular calcium and cAMP: second messengers as "third messengers"? Physiology (Bethesda) 2008; 22:320-7. [PMID: 17928545 DOI: 10.1152/physiol.00019.2007] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Calcium and cyclic AMP are familiar second messengers that typically become elevated inside cells on activation of cell surface receptors. This article will explore emerging evidence that transport of these signaling molecules across the plasma membrane allows them to be recycled as "third messengers," extending their ability to convey information in a domain outside the cell.
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Affiliation(s)
- Aldebaran M Hofer
- Department of Surgery, VA Boston Healthcare System and Brigham & Women's Hospital, Harvard Medical School, West Roxbury, Massachusetts, USA.
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