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Meng F, Li J, Han X, Li L, Li T, Du X, Cao X, Liang Q, Huang A, Kong F, Zeng X, Bu G. TAC3 regulates GnRH/gonadotropin synthesis in female chickens. Theriogenology 2024; 215:302-311. [PMID: 38128223 DOI: 10.1016/j.theriogenology.2023.12.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 12/12/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
Neurokinin B (NKB), a peptide encoded by the tachykinin 3 (TAC3), is critical for reproduction in all studied species. However, its potential roles in birds are less clear. Using the female chicken (c-) as a model, we showed that cTAC3 is composed of five exons with a full-length cDNA of 787 bp, which was predicted to generate the mature NKB peptide containing 10 amino acids. Using cell-based luciferase reporter assays, we demonstrated that cNKB could effectively and specifically activate tachykinin receptor 3 (TACR3) in HEK293 cells, suggesting its physiological function is likely achieved via activating cTACR3 signaling. Notably, cTAC3 and cTACR3 were predominantly and abundantly expressed in the hypothalamus of hens and meanwhile the mRNA expression of cTAC3 was continuously increased during development, suggesting that NKB-TACR3 may emerge as important components of the neuroendocrine reproductive axis. In support, intraperitoneal injection of cNKB could significantly promote hypothalamic cGnRH-Ι, and pituitary cFSHβ and cLHβ expression in female chickens. Surprisingly, cTAC3 and cTACR3 were also expressed in the pituitary gland, and cNKB treatment significantly increased cLHβ and cFSHβ expression in cultured primary pituitary cells, suggesting cNKB can also act directly at the pituitary level to stimulate gonadotropin synthesis. Collectively, our results reveal that cNKB functionally regulate GnRH/gonadotropin synthesis in female chickens.
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Affiliation(s)
- Fengyan Meng
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China.
| | - Jinxuan Li
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China
| | - Xingfa Han
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China
| | - Lingyang Li
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China
| | - Tianyang Li
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China
| | - Xiaogang Du
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China
| | - Xiaohan Cao
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China
| | - Qiuxia Liang
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China
| | - Anqi Huang
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China
| | - Fanli Kong
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China
| | - Xianyin Zeng
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China
| | - Guixian Bu
- College of Life Science, Sichuan Agricultural University, Xinkang Road, Ya'an, 625014, PR China.
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Hibberd TJ, Costa M, Smolilo DJ, Keightley LJ, Brookes SJ, Dinning PG, Spencer NJ. Mechanisms underlying initiation of propulsion in guinea pig distal colon. Am J Physiol Gastrointest Liver Physiol 2022; 323:G71-G87. [PMID: 35502864 DOI: 10.1152/ajpgi.00055.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Colonic motor complexes (CMCs) are a major neurogenic activity in guineapig distal colon. The identity of the enteric neurons that initiate this activity is not established. Specialized intrinsic primary afferent neurons (IPANs) are a major candidate. We aimed to test this hypothesis. To do this, segments of guineapig distal colon were suspended vertically in heated organ baths and propulsive forces acting on a pellet inside the lumen were recorded by isometric force transducer while pharmacological agents were applied to affect IPAN function. In the absence of drugs, CMCs acted periodically on the pellet, generating peak propulsive forces of 12.7 ± 5 g at 0.56 ± 0.22 cpm, lasting 49 ± 17 s (215 preparations; n = 60). Most but not all CMCs were abolished by nicotinic receptor blockade to inhibit fast excitatory synaptic transmission (50/62 preparations; n = 25). Remarkably, CMCs inhibited by hexamethonium were restored by a pharmacological strategy that aimed to enhance IPAN excitability. Thus, CMCs were restored by increased smooth muscle tension (using BAY K8644, bethanechol or carbachol) and by IPAN excitation using phorbol dibutyrate; NK3 receptor agonist, senktide; and partially by αCGRP. The IPAN inhibitor, 5,6-dichloro-1-ethyl-1,3-dihydro-2H-benzimidazole-2-one (DCEBIO), decreased CMC frequency. CGRP, but not NK3-receptor antagonists, decreased CMC frequency in naive preparations. Finally, CMCs were blocked by tetrodotoxin, and this was not reversed by any drugs listed above. These results support a major role for IPANs that does not require fast synaptic transmission, in the periodic initiation of neurogenic propulsive contractions. Endogenous CGRP plays a role in determining CMC frequency, whereas further unidentified signaling pathways may determine their amplitude and duration.NEW & NOTEWORTHY The colonic motor complex (CMC) initiates propulsion in guinea pig colon. Here, CMCs evoked by an intraluminal pellet were restored during nicotinic receptor blockade by pharmacological agents that directly or indirectly enhance intrinsic primary afferent neuron (IPAN) excitability. IPANs are the only enteric neuron in colon that contain CGRP. Blocking CGRP receptors decreased CMC frequency, implicating their role in CMC initiation. The results support a role for IPANs in the initiation of CMCs.
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Affiliation(s)
- Timothy J Hibberd
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Marcello Costa
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - David J Smolilo
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Lauren J Keightley
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Simon J Brookes
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Phil G Dinning
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Nick J Spencer
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
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Zhao P, Pattison LA, Jensen DD, Jimenez-Vargas NN, Latorre R, Lieu T, Jaramillo JO, Lopez-Lopez C, Poole DP, Vanner SJ, Schmidt BL, Bunnett NW. Protein kinase D and Gβγ mediate sustained nociceptive signaling by biased agonists of protease-activated receptor-2. J Biol Chem 2019; 294:10649-10662. [PMID: 31142616 DOI: 10.1074/jbc.ra118.006935] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 05/23/2019] [Indexed: 12/20/2022] Open
Abstract
Proteases sustain hyperexcitability and pain by cleaving protease-activated receptor-2 (PAR2) on nociceptors through distinct mechanisms. Whereas trypsin induces PAR2 coupling to Gαq, Gαs, and β-arrestins, cathepsin-S (CS) and neutrophil elastase (NE) cleave PAR2 at distinct sites and activate it by biased mechanisms that induce coupling to Gαs, but not to Gαq or β-arrestins. Because proteases activate PAR2 by irreversible cleavage, and activated PAR2 is degraded in lysosomes, sustained extracellular protease-mediated signaling requires mobilization of intact PAR2 from the Golgi apparatus or de novo synthesis of new receptors by incompletely understood mechanisms. We found here that trypsin, CS, and NE stimulate PAR2-dependent activation of protein kinase D (PKD) in the Golgi of HEK293 cells, in which PKD regulates protein trafficking. The proteases stimulated translocation of the PKD activator Gβγ to the Golgi, coinciding with PAR2 mobilization from the Golgi. Proteases also induced translocation of a photoconverted PAR2-Kaede fusion protein from the Golgi to the plasma membrane of KNRK cells. After incubation of HEK293 cells and dorsal root ganglia neurons with CS, NE, or trypsin, PAR2 responsiveness initially declined, consistent with PAR2 cleavage and desensitization, and then gradually recovered. Inhibitors of PKD, Gβγ, and protein translation inhibited recovery of PAR2 responsiveness. PKD and Gβγ inhibitors also attenuated protease-evoked mechanical allodynia in mice. We conclude that proteases that activate PAR2 by canonical and biased mechanisms stimulate PKD in the Golgi; PAR2 mobilization and de novo synthesis repopulate the cell surface with intact receptors and sustain nociceptive signaling by extracellular proteases.
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Affiliation(s)
- Peishen Zhao
- From the Monash Institute of Pharmaceutical Sciences and Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Luke A Pattison
- From the Monash Institute of Pharmaceutical Sciences and Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Dane D Jensen
- the Departments of Surgery and Pharmacology, Columbia University Vagelos College of Physicians and Surgeons, Columbia University, New York, New York 10032
| | - Nestor N Jimenez-Vargas
- the Gastrointestinal Diseases Research Unit, Division of Gastroenterology, Queen's University, Kingston, Ontario K7L 3N6, Canada, and
| | - Rocco Latorre
- the Departments of Surgery and Pharmacology, Columbia University Vagelos College of Physicians and Surgeons, Columbia University, New York, New York 10032
| | - TinaMarie Lieu
- From the Monash Institute of Pharmaceutical Sciences and Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Josue O Jaramillo
- the Gastrointestinal Diseases Research Unit, Division of Gastroenterology, Queen's University, Kingston, Ontario K7L 3N6, Canada, and
| | - Cintya Lopez-Lopez
- the Gastrointestinal Diseases Research Unit, Division of Gastroenterology, Queen's University, Kingston, Ontario K7L 3N6, Canada, and
| | - Daniel P Poole
- From the Monash Institute of Pharmaceutical Sciences and Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University, Parkville, Victoria 3052, Australia
| | - Stephen J Vanner
- the Gastrointestinal Diseases Research Unit, Division of Gastroenterology, Queen's University, Kingston, Ontario K7L 3N6, Canada, and
| | - Brian L Schmidt
- the Bluestone Center for Clinical Research, New York University College of Dentistry, New York, New York 10010
| | - Nigel W Bunnett
- the Departments of Surgery and Pharmacology, Columbia University Vagelos College of Physicians and Surgeons, Columbia University, New York, New York 10032,
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Koussoulas K, Gwynne RM, Foong JPP, Bornstein JC. Cholera Toxin Induces Sustained Hyperexcitability in Myenteric, but Not Submucosal, AH Neurons in Guinea Pig Jejunum. Front Physiol 2017; 8:254. [PMID: 28496413 PMCID: PMC5406514 DOI: 10.3389/fphys.2017.00254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 04/10/2017] [Indexed: 01/04/2023] Open
Abstract
Background and Aims: Cholera toxin (CT)-induced hypersecretion requires activation of secretomotor pathways in the enteric nervous system (ENS). AH neurons, which have been identified as a population of intrinsic sensory neurons (ISNs), are a source of excitatory input to the secretomotor pathways. We therefore examined effects of CT in the intestinal lumen on myenteric and submucosal AH neurons. Methods: Isolated segments of guinea pig jejunum were incubated for 90 min with saline plus CT (12.5 μg/ml) or CT + neurotransmitter antagonist, or CT + tetrodotoxin (TTX) in their lumen. After washing CT away, submucosal or myenteric plexus preparations were dissected keeping circumferentially adjacent mucosa intact. Submucosal AH neurons were impaled adjacent to intact mucosa and myenteric AH neurons were impaled adjacent to, more than 5 mm from, and in the absence of intact mucosa. Neuronal excitability was monitored by injecting 500 ms current pulses through the recording electrode. Results: After CT pre-treatment, excitability of myenteric AH neurons adjacent to intact mucosa (n = 29) was greater than that of control neurons (n = 24), but submucosal AH neurons (n = 33, control n = 27) were unaffected. CT also induced excitability increases in myenteric AH neurons impaled distant from the mucosa (n = 6) or in its absence (n = 5). Coincubation with tetrodotoxin or SR142801 (NK3 receptor antagonist), but not SR140333 (NK1 antagonist) or granisetron (5-HT3 receptor antagonist) prevented the increased excitability induced by CT. Increased excitability was associated with a reduction in the characteristic AHP and an increase in the ADP of these neurons, but not a change in the hyperpolarization-activated inward current, Ih. Conclusions: CT increases excitability of myenteric, but not submucosal, AH neurons. This is neurally mediated and depends on NK3, but not 5-HT3 receptors. Therefore, CT may act to amplify the secretomotor response to CT via an increase in the activity of the afferent limb of the enteric reflex circuitry.
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Affiliation(s)
- Katerina Koussoulas
- Enteric Neuroscience Laboratory, Department of Physiology, University of MelbourneParkville, VIC, Australia
| | - Rachel M Gwynne
- Enteric Neuroscience Laboratory, Department of Physiology, University of MelbourneParkville, VIC, Australia
| | - Jaime P P Foong
- Enteric Neuroscience Laboratory, Department of Physiology, University of MelbourneParkville, VIC, Australia
| | - Joel C Bornstein
- Enteric Neuroscience Laboratory, Department of Physiology, University of MelbourneParkville, VIC, Australia
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Poole DP, Bunnett NW. G Protein-Coupled Receptor Trafficking and Signalling in the Enteric Nervous System: The Past, Present and Future. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 891:145-52. [PMID: 27379642 DOI: 10.1007/978-3-319-27592-5_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
G protein-coupled receptors (GPCRs) enable cells to detect and respond to changes in their extracellular environment. With over 800 members, the GPCR family includes receptors for a diverse range of agonists including olfactants, neurotransmitters and hormones. Importantly, GPCRs represent a major therapeutic target, with approximately 50 % of all current drugs acting at some aspect of GPCR signalling (Audet and Bouvier 2008). GPCRs are widely expressed by all cell types in the gastrointestinal (GI) tract and are major regulators of every aspect of gut function. Many GPCRs are internalised upon activation, and this represents one of the mechanisms through which G protein-signalling is terminated. The latency between the endocytosis of GPCRs and their recycling and resensitization is a major determinant of the cell's ability to respond to subsequent exposure to agonists.
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Affiliation(s)
- Daniel P Poole
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia.
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, 3010, Australia.
| | - Nigel W Bunnett
- Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, VIC, 3052, Australia
- Department of Pharmacology and Therapeutics, The University of Melbourne, Parkville, VIC, 3010, Australia
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Coria AS, Masseroni ML, Díaz Añel AM. Regulation of PKD1-mediated Golgi to cell surface trafficking by Gαq subunits. Biol Cell 2013; 106:30-43. [PMID: 24175919 DOI: 10.1111/boc.201300052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 10/28/2013] [Indexed: 11/30/2022]
Abstract
BACKGROUND INFORMATION Heterotrimeric GTP-binding proteins play a key role in cell trafficking regulation. Above all, specific Gβγ subunits have been shown to be a major component of a signal transduction pathway, which also involves phospholipases C (PLC), protein kinases C (PKC) and D (PKD), whose main function is to regulate transport between Golgi and plasma membrane. It was the involvement of PLC which led us to study the role of the other member of this G protein family, the α subunits, in the regulation of membrane fission at the Golgi apparatus. RESULTS Among constitutive active (QL) variants of different G protein α subunit sub-families, only GαqQL subunits were able to induce Golgi fragmentation, a phenotype that mainly reflects a membrane fission increase at this organelle. This phenotype was not observed with a GαqQL palmitoylation mutant, showing the need for a membrane-bounded subunit. Besides, GαqQL-dependent Golgi fission was blocked by specific PLC and PKC inhibitors, and in the presence of a PKD1-kinase dead variant. In addition, GαqQL was the only α subunit capable of inducing PKD1 phosphorylation. Finally, Vesicular Stomatitis Virus thermosensitive mutant glycoprotein (VSVG tsO45) transport assays have demonstrated that GαqQL acts directly on Golgi membranes to regulate trafficking between this organelle and plasma membrane. CONCLUSIONS All these results indicate Gαq subunits for the first time as a regulator of PKD-mediated intracellular trafficking between Golgi apparatus and plasma membrane, opening new perspectives in the understanding of internal trafficking regulation by external signals through G protein-coupled receptors.
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Affiliation(s)
- A Soledad Coria
- Laboratory of Neurobiology and Cell Biology, Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC), CONICET and Universidad Nacional de Córdoba. Friuli 2434, Barrio Parque Vélez Sarsfield, Córdoba 5016, Provincia de Córdoba, Argentina
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Lau WW, Chan AS, Poon LS, Zhu J, Wong YH. Gβγ-mediated activation of protein kinase D exhibits subunit specificity and requires Gβγ-responsive phospholipase Cβ isoforms. Cell Commun Signal 2013; 11:22. [PMID: 23561540 PMCID: PMC3637504 DOI: 10.1186/1478-811x-11-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 03/22/2013] [Indexed: 11/29/2022] Open
Abstract
Background Protein kinase D (PKD) constitutes a novel family of serine/threonine protein kinases implicated in fundamental biological activities including cell proliferation, survival, migration, and immune responses. Activation of PKD in these cellular activities has been linked to many extracellular signals acting through antigen receptor engagement, receptor tyrosine kinases, as well as G protein-coupled receptors. In the latter case, it is generally believed that the Gα subunits of the Gq family are highly effective in mediating PKD activation, whereas little is known with regard to the ability of Gβγ dimers and other Gα subunits to stimulate PKD. It has been suggested that the interaction between Gβγ and the PH domain of PKD, or the Gβγ-induced PLCβ/PKC activity is critical for the induction of PKD activation. However, the relative contribution of these two apparently independent events to Gβγ-mediated PKD activation has yet to be addressed. Results In this report, we demonstrate that among various members in the four G protein families, only the Gα subunits of the Gq family effectively activate all the three PKD isoforms (PKD1/2/3), while Gα subunits of other G protein families (Gs, Gi, and G12) are ineffective. Though the Gα subunits of Gi family are unable to stimulate PKD, receptors linked to Gi proteins are capable of triggering PKD activation in cell lines endogenously expressing (HeLa cells and Jurkat T-cells) or exogenously transfected with (HEK293 cells) Gβγ-sensitive PLCβ2/3 isoforms. This indicates that the Gi-mediated PKD activation is dependent on the released Gβγ dimers upon stimulation. Further investigation on individual Gβγ combinations (i.e. Gβ1 with Gγ1–13) revealed that, even if they can stimulate the PLCβ activity in a comparable manner, only those Gβ1γ dimers with γ2, γ3, γ4, γ5, γ7, and γ10 can serve as effective activators of PKD. We also demonstrated that Gi-mediated PKD activation is essential for the SDF-1α-induced chemotaxis on Jurkat T-cells. Conclusions Our current report illustrates that Gβγ dimers from the Gi proteins may activate PKD in a PLCβ2/3-dependent manner, and the specific identities of Gγ components within Gβγ dimers may determine this stimulatory action.
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Affiliation(s)
- Winnie Wi Lau
- Division of Life Science and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
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Thomson ABR, Chopra A, Clandinin MT, Freeman H. Recent advances in small bowel diseases: Part II. World J Gastroenterol 2012; 18:3353-74. [PMID: 22807605 PMCID: PMC3396188 DOI: 10.3748/wjg.v18.i26.3353] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 04/05/2012] [Accepted: 04/13/2012] [Indexed: 02/06/2023] Open
Abstract
As is the case in all areas of gastroenterology and hepatology, in 2009 and 2010 there were many advances in our knowledge and understanding of small intestinal diseases. Over 1000 publications were reviewed, and the important advances in basic science as well as clinical applications were considered. In Part II we review six topics: absorption, short bowel syndrome, smooth muscle function and intestinal motility, tumors, diagnostic imaging, and cystic fibrosis.
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Carrasquero LMG, Delicado EG, Sánchez-Ruiloba L, Iglesias T, Miras-Portugal MT. Mechanisms of protein kinase D activation in response to P2Y(2) and P2X7 receptors in primary astrocytes. Glia 2010; 58:984-95. [PMID: 20222145 DOI: 10.1002/glia.20980] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Protein kinase D (PKD) is a family of serine/threonine kinases that can be activated by many stimuli via protein kinase C in a variety of cells. This is the first report where PKD activation and localization is studied in glial cells. Herein, we demonstrate that P2Y(2) and P2X7 receptor stimulation of primary rat cerebellar astrocytes rapidly increases PKD1/2 phosphorylation and activity. P2Y(2) receptor response evokes a PKD1/2 activation that is dependent on a pertussis toxin-insensitive G protein, phospholipase C (PLC)-mediated generation of diacylglycerol, and protein kinase C. This mechanism is similar to the one described for other G-protein coupled receptors. In contrast, the way the ionotropic P2X7 receptor activates PKD1/2 is significantly different. Importantly, this response is not dependent on calcium entry, but depends on the activity of several phospholipases, including phosphoinositide-phospholipase C (PI-PLC), phosphatidylcholine-phospholipase C (PC-PLC) and also phospholipase D (PLD). Immunoblot and confocal microscopy analysis show that PKD1/2 activation by nucleotides is transient. The active kinase first moves to and concentrates in certain plasma membrane domains. Then, phosphorylated-PKD1/2 translocates to intracellular vesicles, where it remains active. All together, our results open the perspective of PKD1/2 being involved in many physiological functions where nucleotides play important roles not only in astrocytes but in other cell types bearing these receptors.
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Affiliation(s)
- Luz María G Carrasquero
- Departamento de Bioquímica, Facultad de Veterinaria, Universidad Complutense de Madrid, Madrid 28040, Spain
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Darmani NA, Ray AP. Evidence for a re-evaluation of the neurochemical and anatomical bases of chemotherapy-induced vomiting. Chem Rev 2009; 109:3158-99. [PMID: 19522506 DOI: 10.1021/cr900117p] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Nissar A Darmani
- Department of Basic Medical Sciences, College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, California 91766-1854, USA.
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Amadesi S, Grant AD, Cottrell GS, Vaksman N, Poole DP, Rozengurt E, Bunnett NW. Protein kinase D isoforms are expressed in rat and mouse primary sensory neurons and are activated by agonists of protease-activated receptor 2. J Comp Neurol 2009; 516:141-56. [PMID: 19575452 DOI: 10.1002/cne.22104] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Serine proteases generated during injury and inflammation cleave protease-activated receptor 2 (PAR(2)) on primary sensory neurons to induce neurogenic inflammation and hyperalgesia. Hyperalgesia requires sensitization of transient receptor potential vanilloid (TRPV) ion channels by mechanisms involving phospholipase C and protein kinase C (PKC). The protein kinase D (PKD) serine/threonine kinases are activated by diacylglycerol and PKCs and can phosphorylate TRPV1. Thus, PKDs may participate in novel signal transduction pathways triggered by serine proteases during inflammation and pain. However, it is not known whether PAR(2) activates PKD, and the expression of PKD isoforms by nociceptive neurons is poorly characterized. By using HEK293 cells transfected with PKDs, we found that PAR(2) stimulation promoted plasma membrane translocation and phosphorylation of PKD1, PKD2, and PKD3, indicating activation. This effect was partially dependent on PKCepsilon. By immunofluorescence and confocal microscopy, with antibodies against PKD1/PKD2 and PKD3 and neuronal markers, we found that PKDs were expressed in rat and mouse dorsal root ganglia (DRG) neurons, including nociceptive neurons that expressed TRPV1, PAR(2), and neuropeptides. PAR(2) agonist induced phosphorylation of PKD in cultured DRG neurons, indicating PKD activation. Intraplantar injection of PAR(2) agonist also caused phosphorylation of PKD in neurons of lumbar DRG, confirming activation in vivo. Thus, PKD1, PKD2, and PKD3 are expressed in primary sensory neurons that mediate neurogenic inflammation and pain transmission, and PAR(2) agonists activate PKDs in HEK293 cells and DRG neurons in culture and in intact animals. PKD may be a novel component of a signal transduction pathway for protease-induced activation of nociceptive neurons and an important new target for antiinflammatory and analgesic therapies.
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Affiliation(s)
- Silvia Amadesi
- Center for Neurobiology of Digestive Diseases, University of California, San Francisco, San Francisco, California 94143-0660, USA
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Affiliation(s)
- James J Galligan
- Department of Pharmacology & Toxicology and the Neuroscience Program, Michigan State University, East Lansing, 48824, USA.
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Motagally MA, Lukewich MK, Chisholm SP, Neshat S, Lomax AE. Tumour necrosis factor alpha activates nuclear factor kappaB signalling to reduce N-type voltage-gated Ca2+ current in postganglionic sympathetic neurons. J Physiol 2009; 587:2623-34. [PMID: 19403618 DOI: 10.1113/jphysiol.2009.172312] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Inflammation has profound effects on the innervation of affected tissues, including altered neuronal excitability and neurotransmitter release. As Ca(2+) influx through voltage-gated Ca(2+) channels (VGCCs) is a critical determinant of excitation-secretion coupling in nerve terminals, the aim of this study was to characterize the effect of overnight incubation in the inflammatory mediator tumour necrosis factor alpha (TNFalpha; 1 nM) on VGCCs in dissociated neurons from mouse superior mesenteric ganglia (SMG). Voltage-gated Ca(2+) currents (I(Ca)) were measured using the perforated patch clamp technique and the VGCC subtypes present in SMG neurons were estimated based on inhibition by selective VGCC blockers: omega-conotoxin GVIA (300 nM; N-type), nifedipine (10 microM; L-type), and omega-conotoxin MVIIC (300 nM; N-, P/Q-type). We used intracellular Ca(2+) imaging with Fura-2 AM to compare Ca(2+) influx during depolarizations in control and TNFalpha-treated neurons. TNF receptor and VGCC mRNA expression were measured using PCR, and channel alpha subunit (CaV2.2) was localized with immunohistochemistry. Incubation in TNFalpha significantly decreased I(Ca) amplitude and depolarization-induced Ca(2+) influx. The reduction in I(Ca) was limited to omega-conotoxin GVIA-sensitive N-type Ca(2+) channels. Depletion of glial cells by incubation in cytosine arabinoside (5 microM) did not affect I(Ca) inhibition by TNFalpha. Preincubation of neurons with SC-514 (20 microM) or BAY 11-7082 (1 microM), which both inhibit nuclear factor kappaB signalling, prevented the reduction in I(Ca) by TNFalpha. Inhibition of N-type VGCCs following TNFalpha incubation was associated with a decrease in CaV2.2 mRNA and reduced membrane localization of CaV2.2 immunoreactivity. These data suggest that TNFalpha inhibits I(Ca) in SMG neurons and identify a novel role for NF-kappaB in the regulation of neurotransmitter release during inflammatory conditions with elevated circulating TNFalpha, such as Crohn's disease and Guillain-Barré syndrome.
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Copel C, Osorio N, Crest M, Gola M, Delmas P, Clerc N. Activation of neurokinin 3 receptor increases Na(v)1.9 current in enteric neurons. J Physiol 2009; 587:1461-79. [PMID: 19204045 DOI: 10.1113/jphysiol.2009.169409] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The intrinsic primary afferent neurons (IPANs) of the guinea pig enteric nervous system express Na(v)1.9 sodium channels that produce a persistent TTX-resistant current having a low activation threshold and slow gating kinetics. These neurons receive slow EPSPs induced mainly by the activation of neurokinin 3 receptors (NK3r). Here, we demonstrate that senktide, a specific NK3r agonist, potentiates the Na(v)1.9 current (I(Nav1.9)) in IPANs. Using whole-cell patch-clamp recordings from IPANs in duodenum longitudinal muscle/myenteric plexus preparations, we show that short (1-5 s) and long (up to 1 min) applications of senktide, increase the I(Nav1.9) peak current up to 13-fold. The effect, blocked by a NK3r antagonist SB235375 is transient, lasting approximately 2 min and is due to a negative shift of the activation voltage by approximately 20 mV and of fast inactivation by approximately 10 mV. As a consequence, the window current resulting from the product of the activation and fast inactivation curves is shifted and enlarged. The transient effect of senktide is likely to be due to the fast desensitization of NK3r. Protein kinase C (PKC) activation with phorbol or oleoyl acetylglycerol also increases I(Nav1.9), although persistently, by inducing similar voltage-dependent changes. Current-clamp experiments showed that I(Nav1.9) modulation by senktide lowers action potential threshold and increases excitability. The increase in I(Nav1.9) by NK3r activation is also likely to amplify slow EPSPs generated in the IPANs. These changes in excitability potentially have a profound effect on the entire enteric synaptic circuit and ultimately on gut motility and secretion.
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Affiliation(s)
- Carine Copel
- UMR, CNRS/Université de la Méditerranée/Université Paul Cézanne, Marseille, France
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Haley GE, Flynn FW. Blockade of NK3R signaling in the PVN decreases vasopressin and oxytocin release and c-Fos expression in the magnocellular neurons in response to hypotension. Am J Physiol Regul Integr Comp Physiol 2008; 295:R1158-67. [PMID: 18650316 DOI: 10.1152/ajpregu.90402.2008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tachykinin neurokinin 3 receptor (NK3R) signaling has a broad role in vasopressin (VP) and oxytocin (OT) release. Hydralazine (HDZ)-induced hypotension activates NK3R expressed by magnocellular neurons, increases plasma VP and OT levels, and induces c-Fos expression in VP and OT neurons. Intraventricular pretreatment with the specific NK3R antagonist, SB-222200, eliminates the HDZ-stimulated VP and OT release. NK3R are distributed in the central pathways conveying hypotension information to the magnocellular neurons, and the NK3R antagonist could act anywhere in the pathways. Alternatively, the antagonist could act at the NK3R expressed by the magnocellular neurons. To determine whether blockade of NK3R on magnocellular neurons impairs VP and OT release to HDZ, rats were pretreated with a unilateral PVN injection of 0.15 M NaCl or SB-222200 prior to an intravenous injection of 0.15 M NaCl or HDZ. Blood samples were taken, and brains were processed for VP/c-Fos and OT/c-Fos immunohistochemistry. Intravenous injection of 0.15 M NaCl did not alter plasma hormone levels, and little c-Fos immunoreactivity was present in the PVN. Conversely, intravenous injection of HDZ increased plasma VP and OT levels and c-Fos expression in VP and OT magnocellular neurons. Intra-PVN injection of SB-222200 prior to an intravenous injection of HDZ significantly decreased c-Fos expression in both VP and OT neurons by approximately 70% and attenuated plasma VP and OT levels by 33% and 35%, respectively. Therefore, NK3R signaling in magnocellular neurons has a critical role for the release of VP and OT in response to hypotension.
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Affiliation(s)
- Gwendolen E Haley
- Graduate Neuroscience Program, University of Wyoming, Laramie, Wyoming 82071, USA
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