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Maghsoudi S, Shuaib R, Van Bastelaere B, Dakshinamurti S. Adenylyl cyclase isoforms 5 and 6 in the cardiovascular system: complex regulation and divergent roles. Front Pharmacol 2024; 15:1370506. [PMID: 38633617 PMCID: PMC11021717 DOI: 10.3389/fphar.2024.1370506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/11/2024] [Indexed: 04/19/2024] Open
Abstract
Adenylyl cyclases (ACs) are crucial effector enzymes that transduce divergent signals from upstream receptor pathways and are responsible for catalyzing the conversion of ATP to cAMP. The ten AC isoforms are categorized into four main groups; the class III or calcium-inhibited family of ACs comprises AC5 and AC6. These enzymes are very closely related in structure and have a paucity of selective activators or inhibitors, making it difficult to distinguish them experimentally. AC5 and AC6 are highly expressed in the heart and vasculature, as well as the spinal cord and brain; AC6 is also abundant in the lungs, kidney, and liver. However, while AC5 and AC6 have similar expression patterns with some redundant functions, they have distinct physiological roles due to differing regulation and cAMP signaling compartmentation. AC5 is critical in cardiac and vascular function; AC6 is a key effector of vasodilatory pathways in vascular myocytes and is enriched in fetal/neonatal tissues. Expression of both AC5 and AC6 decreases in heart failure; however, AC5 disruption is cardio-protective, while overexpression of AC6 rescues cardiac function in cardiac injury. This is a comprehensive review of the complex regulation of AC5 and AC6 in the cardiovascular system, highlighting overexpression and knockout studies as well as transgenic models illuminating each enzyme and focusing on post-translational modifications that regulate their cellular localization and biological functions. We also describe pharmacological challenges in the design of isoform-selective activators or inhibitors for AC5 and AC6, which may be relevant to developing new therapeutic approaches for several cardiovascular diseases.
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Affiliation(s)
- Saeid Maghsoudi
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
- Biology of Breathing Group, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Rabia Shuaib
- Biology of Breathing Group, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Ben Van Bastelaere
- Biology of Breathing Group, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
| | - Shyamala Dakshinamurti
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB, Canada
- Biology of Breathing Group, Children’s Hospital Research Institute of Manitoba, Winnipeg, MB, Canada
- Section of Neonatology, Department of Pediatrics, Health Sciences Centre, Winnipeg, MB, Canada
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2
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Bhatia V, Maghsoudi S, Hinton M, Bhagirath AY, Singh N, Jaggupilli A, Chelikani P, Dakshinamurti S. Characterization of Adenylyl Cyclase Isoform 6 Residues Interacting with Forskolin. BIOLOGY 2023; 12:biology12040572. [PMID: 37106773 PMCID: PMC10135528 DOI: 10.3390/biology12040572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/26/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023]
Abstract
BACKGROUND The adenylyl cyclase (AC) pathway, crucial for pulmonary vasodilation, is inhibited by hypoxia. Forskolin (FSK) binds allosterically to AC, stimulating ATP catalysis. As AC6 is the primary AC isoform in the pulmonary artery, selective reactivation of AC6 could provide targeted reinstatement of hypoxic AC activity. This requires elucidation of the FSK binding site in AC6. METHODS HEK293T cells stably overexpressing AC 5, 6, or 7 were incubated in normoxia (21% O2) or hypoxia (10% O2) or exposed to s-nitrosocysteine (CSNO). AC activity was measured using terbium norfloxacin assay; AC6 structure built by homology modeling; ligand docking to examine FSK-interacting amino acids; roles of selected residues determined by site-directed mutagenesis; FSK-dependent cAMP generation measured in wild-type and FSK-site mutants by biosensor-based live cell assay. RESULTS Only AC6 is inhibited by hypoxia and nitrosylation. Homology modeling and docking revealed residues T500, N503, and S1035 interacting with FSK. Mutation of T500, N503, or S1035 decreased FSK-stimulated AC activity. FSK site mutants were not further inhibited by hypoxia or CSNO; however, mutation of any of these residues prevented AC6 activation by FSK following hypoxia or CSNO treatment. CONCLUSIONS FSK-interacting amino acids are not involved in the hypoxic inhibition mechanism. This study provides direction to design FSK derivatives for selective activation of hypoxic AC6.
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Affiliation(s)
- Vikram Bhatia
- Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada
- Department of Oral Biology, University of Manitoba, Winnipeg, MB R3E 0W2, Canada
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB R3A 1S1, Canada
| | - Saeid Maghsoudi
- Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Martha Hinton
- Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Anjali Y Bhagirath
- Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada
- Department of Oral Biology, University of Manitoba, Winnipeg, MB R3E 0W2, Canada
| | - Nisha Singh
- Department of Oral Biology, University of Manitoba, Winnipeg, MB R3E 0W2, Canada
| | | | - Prashen Chelikani
- Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada
- Department of Oral Biology, University of Manitoba, Winnipeg, MB R3E 0W2, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Shyamala Dakshinamurti
- Biology of Breathing Theme, Children's Hospital Research Institute of Manitoba, Winnipeg, MB R3E 3P4, Canada
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, MB R3A 1S1, Canada
- Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
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Qiu ZE, Xu JB, Chen L, Huang ZX, Lei TL, Huang ZY, Hou XC, Yang HL, Lin QH, Zhu YX, Zhao L, Zhou WL, Zhang YL. Allicin Facilitates Airway Surface Liquid Hydration by Activation of CFTR. Front Pharmacol 2022; 13:890284. [PMID: 35784719 PMCID: PMC9241074 DOI: 10.3389/fphar.2022.890284] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 05/20/2022] [Indexed: 11/16/2022] Open
Abstract
Airway epithelium plays critical roles in regulating airway surface liquid (ASL), the alteration of which causes mucus stasis symptoms. Allicin is a compound released from garlic and harbors the capacity of lung-protection. However, the potential regulatory effects of allicin on airway epithelium remain elusive. This study aimed to investigate the effects of allicin on ion transport across airway epithelium and evaluate its potential as an expectorant. Application of allicin induced Cl− secretion across airway epithelium in a concentration-dependent manner. Blockade of cystic fibrosis transmembrane conductance regulator (CFTR) or inhibition of adenylate cyclase-cAMP signaling pathway attenuated allicin-induced Cl− secretion in airway epithelial cells. The in vivo study showed that inhaled allicin significantly increased the ASL secretion in mice. These results suggest that allicin induces Cl− and fluid secretion across airway epithelium via activation of CFTR, which might provide therapeutic strategies for the treatment of chronic pulmonary diseases associated with ASL dehydration.
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Affiliation(s)
- Zhuo-Er Qiu
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jian-Bang Xu
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
| | - Lei Chen
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Ze-Xin Huang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Tian-Lun Lei
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zi-Yang Huang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Xiao-Chun Hou
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Hai-Long Yang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Qin-Hua Lin
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yun-Xin Zhu
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Lei Zhao
- State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
- Department of Physiology, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China
- *Correspondence: Lei Zhao, ; Wen-Liang Zhou, ; Yi-Lin Zhang,
| | - Wen-Liang Zhou
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- *Correspondence: Lei Zhao, ; Wen-Liang Zhou, ; Yi-Lin Zhang,
| | - Yi-Lin Zhang
- School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- *Correspondence: Lei Zhao, ; Wen-Liang Zhou, ; Yi-Lin Zhang,
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PDE-Mediated Cyclic Nucleotide Compartmentation in Vascular Smooth Muscle Cells: From Basic to a Clinical Perspective. J Cardiovasc Dev Dis 2021; 9:jcdd9010004. [PMID: 35050214 PMCID: PMC8777754 DOI: 10.3390/jcdd9010004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 12/18/2021] [Accepted: 12/20/2021] [Indexed: 12/14/2022] Open
Abstract
Cardiovascular diseases are important causes of mortality and morbidity worldwide. Vascular smooth muscle cells (SMCs) are major components of blood vessels and are involved in physiologic and pathophysiologic conditions. In healthy vessels, vascular SMCs contribute to vasotone and regulate blood flow by cyclic nucleotide intracellular pathways. However, vascular SMCs lose their contractile phenotype under pathological conditions and alter contractility or signalling mechanisms, including cyclic nucleotide compartmentation. In the present review, we focus on compartmentalized signaling of cyclic nucleotides in vascular smooth muscle. A deeper understanding of these mechanisms clarifies the most relevant axes for the regulation of vascular tone. Furthermore, this allows the detection of possible changes associated with pathological processes, which may be of help for the discovery of novel drugs.
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Bhagirath AY, Bhatia V, Medapati MR, Singh N, Hinton M, Chelikani P, Dakshinamurti S. Critical cysteines in the functional interaction of adenylyl cyclase isoform 6 with Gαs. FASEB Bioadv 2021; 4:180-196. [PMID: 35664968 PMCID: PMC9159366 DOI: 10.1096/fba.2021-00073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/11/2021] [Accepted: 11/08/2021] [Indexed: 11/17/2022] Open
Abstract
Activation of adenylyl cyclases (ACs) by G‐protein Gαs catalyzes the production of cyclic adenosine monophosphate (cAMP), a key second messenger that regulates diverse physiological responses. There are 10 AC isoforms present in humans, with AC5 and AC6 proposed to play vital roles in cardiac function. We have previously shown that under hypoxic conditions, AC6 is amenable to post‐translational modification by nitrosylation, resulting in decreased AC catalytic activity. Using a computational model of the AC6–Gαs complex, we predicted key nitrosylation‐amenable cysteine residues involved in the interaction of AC6 with Gαs and pursued a structure–function analysis of these cysteine residues in both AC6 and Gαs. Our results based on site‐directed mutagenesis of AC6 and Gαs, a constitutively active Gαs, AC activity, and live cell intracellular cAMP assays suggest that Cys1004 in AC6 (subunit C2) and Cys237 in Gαs are present at the AC–Gαs interface and are important for the activation of AC6 by Gαs. We further provide mechanistic evidence to show that mutating Cys 1004 in the second catalytic domain of AC6 makes it amenable to inhibition by Gαi, which may account for decreased functional activity of AC6 when this residue is unavailable.
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Affiliation(s)
- Anjali Y. Bhagirath
- Biology of Breathing Theme Children's Hospital Research Institute of Manitoba (CHRIM) Winnipeg Manitoba Canada
- Department of Oral Biology University of Manitoba Winnipeg Manitoba Canada
| | - Vikram Bhatia
- Biology of Breathing Theme Children's Hospital Research Institute of Manitoba (CHRIM) Winnipeg Manitoba Canada
- Department of Oral Biology University of Manitoba Winnipeg Manitoba Canada
| | | | - Nisha Singh
- Department of Oral Biology University of Manitoba Winnipeg Manitoba Canada
| | - Martha Hinton
- Biology of Breathing Theme Children's Hospital Research Institute of Manitoba (CHRIM) Winnipeg Manitoba Canada
- Department of Physiology and Pathophysiology University of Manitoba Winnipeg Manitoba Canada
| | - Prashen Chelikani
- Biology of Breathing Theme Children's Hospital Research Institute of Manitoba (CHRIM) Winnipeg Manitoba Canada
- Department of Oral Biology University of Manitoba Winnipeg Manitoba Canada
| | - Shyamala Dakshinamurti
- Biology of Breathing Theme Children's Hospital Research Institute of Manitoba (CHRIM) Winnipeg Manitoba Canada
- Department of Physiology and Pathophysiology University of Manitoba Winnipeg Manitoba Canada
- Department of Pediatrics University of Manitoba Winnipeg Manitoba Canada
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6
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Bhatia V, Elnagary L, Dakshinamurti S. Tracing the path of inhaled nitric oxide: Biological consequences of protein nitrosylation. Pediatr Pulmonol 2021; 56:525-538. [PMID: 33289321 DOI: 10.1002/ppul.25201] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/28/2020] [Accepted: 11/29/2020] [Indexed: 12/12/2022]
Abstract
Nitric oxide (NO) is a comprehensive regulator of vascular and airway tone. Endogenous NO produced by nitric oxide synthases regulates multiple signaling cascades, including activation of soluble guanylate cyclase to generate cGMP, relaxing smooth muscle cells. Inhaled NO is an established therapy for pulmonary hypertension in neonates, and has been recently proposed for the treatment of hypoxic respiratory failure and acute respiratory distress syndrome due to COVID-19. In this review, we summarize the effects of endogenous and exogenous NO on protein S-nitrosylation, which is the selective and reversible covalent attachment of a nitrogen monoxide group to the thiol side chain of cysteine. This posttranslational modification targets specific cysteines based on the acid/base sequence of surrounding residues, with significant impacts on protein interactions and function. S-nitrosothiol (SNO) formation is tightly compartmentalized and enzymatically controlled, but also propagated by nonenzymatic transnitrosylation of downstream protein targets. Redox-based nitrosylation and denitrosylation pathways dynamically regulate the equilibrium of SNO-proteins. We review the physiological roles of SNO proteins, including nitrosohemoglobin and autoregulation of blood flow through hypoxic vasodilation, and pathological effects of nitrosylation including inhibition of critical vasodilator enzymes; and discuss the intersection of NO source and dose with redox environment, in determining the effects of protein nitrosylation.
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Affiliation(s)
- Vikram Bhatia
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, Canada
| | - Lara Elnagary
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, Canada
| | - Shyamala Dakshinamurti
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba, University of Manitoba, Winnipeg, Canada.,Section of Neonatology, Departments of Pediatrics and Physiology, University of Manitoba, Winnipeg, Canada
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Effects of Post-translational Modifications on Membrane Localization and Signaling of Prostanoid GPCR-G Protein Complexes and the Role of Hypoxia. J Membr Biol 2019; 252:509-526. [PMID: 31485700 DOI: 10.1007/s00232-019-00091-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/17/2019] [Indexed: 02/07/2023]
Abstract
G protein-coupled receptors (GPCRs) play a pivotal role in the adaptive responses to cellular stresses such as hypoxia. In addition to influencing cellular gene expression profiles, hypoxic microenvironments can perturb membrane protein localization, altering GPCR effector scaffolding and altering downstream signaling. Studies using proteomics approaches have revealed significant regulation of GPCR and G proteins by their state of post-translational modification. The aim of this review is to examine the effects of post-translational modifications on membrane localization and signaling of GPCR-G protein complexes, with an emphasis on vascular prostanoid receptors, and to highlight what is known about the effect of cellular hypoxia on these mechanisms. Understanding post-translational modifications of protein targets will help to define GPCR targets in treatment of disease, and to inform research into mechanisms of hypoxic cellular responses.
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8
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Jaggupilli A, Howard R, Aluko RE, Chelikani P. Advanced Glycation End-Products Can Activate or Block Bitter Taste Receptors. Nutrients 2019; 11:nu11061317. [PMID: 31212814 PMCID: PMC6628017 DOI: 10.3390/nu11061317] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 06/07/2019] [Accepted: 06/10/2019] [Indexed: 12/14/2022] Open
Abstract
Bitter taste receptors (T2Rs) are expressed in several tissues of the body and are involved in a variety of roles apart from bitter taste perception. Advanced glycation end-products (AGEs) are produced by glycation of amino acids in proteins. There are varying sources of AGEs, including dietary food products, as well as endogenous reactions within our body. Whether these AGEs are T2R ligands remains to be characterized. In this study, we selected two AGEs, namely, glyoxal-derived lysine dimer (GOLD) and carboxymethyllysine (CML), based on their predicted interaction with the well-studied T2R4, and its physiochemical properties. Results showed predicted binding affinities (Kd) for GOLD and CML towards T2R4 in the nM and μM range, respectively. Calcium mobilization assays showed that GOLD inhibited quinine activation of T2R4 with IC50 10.52 ± 4.7 μM, whilst CML was less effective with IC50 32.62 ± 9.5 μM. To characterize whether this antagonism was specific to quinine activated T2R4 or applicable to other T2Rs, we selected T2R14 and T2R20, which are expressed at significant levels in different human tissues. A similar effect of GOLD was observed with T2R14; and in contrast, GOLD and CML activated T2R20 with an EC50 of 79.35 ± 29.16 μM and 65.31 ± 17.79 μM, respectively. In this study, we identified AGEs as novel T2R ligands that caused either activation or inhibition of different T2Rs.
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Affiliation(s)
- Appalaraju Jaggupilli
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada.
| | - Ryan Howard
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada.
| | - Rotimi E Aluko
- Department of Food and Human Nutritional Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.
| | - Prashen Chelikani
- Manitoba Chemosensory Biology Research Group, Department of Oral Biology, University of Manitoba, Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB R3E 0W4, Canada.
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Sikarwar AS, Hinton M, Santhosh KT, Dhanaraj P, Talabis M, Chelikani P, Dakshinamurti S. Hypoxia inhibits adenylyl cyclase catalytic activity in a porcine model of persistent pulmonary hypertension of the newborn. Am J Physiol Lung Cell Mol Physiol 2018; 315:L933-L944. [PMID: 30234376 DOI: 10.1152/ajplung.00130.2018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Persistent pulmonary hypertension of the newborn (PPHN) features hypoxemia, pulmonary vasoconstriction, and impaired cardiac inotropy. We previously reported low basal and stimulated cAMP in hypoxic pulmonary artery smooth muscle cells (PASMCs). We now examine pulmonary arterial adenylyl cyclase (AC) activity and regulation in hypoxic PPHN. PPHN was induced in newborn swine by normobaric hypoxia (fraction of inspired oxygen 0.10) for 72 h and compared with age-matched normoxic controls. We studied relaxation of pulmonary arterial (PA) rings to AC activator forskolin and cGMP activator sodium nitroprusside (SNP) by isometric myography, ATP content, phosphodiesterase activity, AC content, isoform expression, and catalytic activity in presence or absence of Gαs-coupled receptor agonists, forskolin, or transnitrosylating agents in human and neonatal porcine PASMCs and HEK293T stably expressing AC isoform 6, after 72 h hypoxia (10% O2) or normoxia (21% O2). Relaxation to forskolin and SNP were equally impaired in PPHN PA. AC-specific activity decreased in hypoxia. PASMC from PPHN swine had reduced AC activity despite exposure to normoxia in culture; transient hypoxia in vitro further decreased AC activity. Prostacyclin receptor ligand affinity decreased, but its association with Gαs increased in hypoxia. Total AC content was unchanged by hypoxia, but AC6 increased in hypoxic cells and PPHN pulmonary arteries. Impairment of AC6 activity in hypoxia was associated with nitrosylation. PPHN PA relaxation is impaired because of loss of AC activity. Hypoxic AC is inhibited because of S-nitrosylation; inhibition persists after removal from hypoxia. Downregulation of AC-mediated relaxation in hypoxic PA has implications for utility of Gαs-coupled receptor agonists in PPHN treatment.
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Affiliation(s)
- A S Sikarwar
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba , Winnipeg , Canada.,Department of Physiology, University of Manitoba , Winnipeg , Canada.,Department of Oral Biology, University of Manitoba , Winnipeg , Canada
| | - M Hinton
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba , Winnipeg , Canada
| | - K T Santhosh
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba , Winnipeg , Canada
| | - P Dhanaraj
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba , Winnipeg , Canada.,Department of Oral Biology, University of Manitoba , Winnipeg , Canada
| | - M Talabis
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba , Winnipeg , Canada
| | - P Chelikani
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba , Winnipeg , Canada.,Department of Oral Biology, University of Manitoba , Winnipeg , Canada
| | - S Dakshinamurti
- Biology of Breathing Group, Children's Hospital Research Institute of Manitoba , Winnipeg , Canada.,Department of Physiology, University of Manitoba , Winnipeg , Canada.,Department of Pediatrics, University of Manitoba , Winnipeg , Canada
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Childers KC, Garcin ED. Structure/function of the soluble guanylyl cyclase catalytic domain. Nitric Oxide 2018; 77:53-64. [PMID: 29702251 PMCID: PMC6005667 DOI: 10.1016/j.niox.2018.04.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 02/06/2023]
Abstract
Soluble guanylyl cyclase (GC-1) is the primary receptor of nitric oxide (NO) in smooth muscle cells and maintains vascular function by inducing vasorelaxation in nearby blood vessels. GC-1 converts guanosine 5′-triphosphate (GTP) into cyclic guanosine 3′,5′-monophosphate (cGMP), which acts as a second messenger to improve blood flow. While much work has been done to characterize this pathway, we lack a mechanistic understanding of how NO binding to the heme domain leads to a large increase in activity at the C-terminal catalytic domain. Recent structural evidence and activity measurements from multiple groups have revealed a low-activity cyclase domain that requires additional GC-1 domains to promote a catalytically-competent conformation. How the catalytic domain structurally transitions into the active conformation requires further characterization. This review focuses on structure/function studies of the GC-1 catalytic domain and recent advances various groups have made in understanding how catalytic activity is regulated including small molecules interactions, Cys-S-NO modifications and potential interactions with the NO-sensor domain and other proteins.
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Affiliation(s)
- Kenneth C Childers
- University of Maryland Baltimore County, Department of Chemistry and Biochemistry, Baltimore, USA
| | - Elsa D Garcin
- University of Maryland Baltimore County, Department of Chemistry and Biochemistry, Baltimore, USA.
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