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Beretta M, Dai Y, Olzomer EM, Vancuylenburg CS, Santiago-Rivera JA, Philp AM, Hargett SR, Li K, Shah DP, Chen SY, Alexopoulos SJ, Li C, Harris TE, Lee B, Wathier M, Cermak JM, Tucker SP, Turner N, Bayliss DA, Philp A, Byrne FL, Santos WL, Hoehn KL. Liver-Selective Imidazolopyrazine Mitochondrial Uncoupler SHD865 Reverses Adiposity and Glucose Intolerance in Mice. Diabetes 2024; 73:374-384. [PMID: 37870907 PMCID: PMC10882157 DOI: 10.2337/db23-0233] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 10/04/2023] [Indexed: 10/24/2023]
Abstract
Excess body fat is a risk factor for metabolic diseases and is a leading preventable cause of morbidity and mortality worldwide. There is a strong need to find new treatments that decrease the burden of obesity and lower the risk of obesity-related comorbidities, including cardiovascular disease and type 2 diabetes. Pharmacologic mitochondrial uncouplers represent a potential treatment for obesity through their ability to increase nutrient oxidation. Herein, we report the in vitro and in vivo characterization of compound SHD865, the first compound to be studied in vivo in a newly discovered class of imidazolopyrazine mitochondrial uncouplers. SHD865 is a derivative of the furazanopyrazine uncoupler BAM15. SHD865 is a milder mitochondrial uncoupler than BAM15 that results in a lower maximal respiration rate. In a mouse model of diet-induced adiposity, 6-week treatment with SHD865 completely restored normal body composition and glucose tolerance to levels like those of chow-fed controls, without altering food intake. SHD865 treatment also corrected liver steatosis and plasma hyperlipidemia to normal levels comparable with chow-fed controls. SHD865 has maximal oral bioavailability in rats and slow clearance in human microsomes and hepatocytes. Collectively, these data identify the potential of imidazolopyrazine mitochondrial uncouplers as drug candidates for the treatment of obesity-related disorders. ARTICLE HIGHLIGHTS
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Affiliation(s)
- Martina Beretta
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Yumin Dai
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA
| | - Ellen M. Olzomer
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Calum S. Vancuylenburg
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - José A. Santiago-Rivera
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA
| | - Ashleigh M. Philp
- St Vincent’s Clinical School, UNSW Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Stefan R. Hargett
- Department of Pharmacology, University of Virginia, Charlottesville, VA
| | - Keyong Li
- Department of Pharmacology, University of Virginia, Charlottesville, VA
| | - Divya P. Shah
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Sing-Young Chen
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Stephanie J. Alexopoulos
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Catherine Li
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Thurl E. Harris
- Department of Pharmacology, University of Virginia, Charlottesville, VA
| | - Brendan Lee
- Biological Resources Imaging Laboratory, University of New South Wales, Sydney, New South Wales, Australia
| | | | | | - Simon P. Tucker
- Life Biosciences, Boston, MA
- Firebrick Pharma, Melbourne, Victoria, Australia
| | - Nigel Turner
- Cellular Bioenergetics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia
| | | | - Andrew Philp
- Centre for Healthy Ageing, Centenary Institute, Camperdown, New South Wales, Australia
- School of Sport, Exercise and Rehabilitation Sciences, University of Technology Sydney, Sydney, New South Wales, Australia
- Charles Perkins Centre, The University of Sydney, Camperdown, New South Wales, Australia
| | - Frances L. Byrne
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Webster L. Santos
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA
| | - Kyle L. Hoehn
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington, New South Wales, Australia
- Department of Pharmacology, University of Virginia, Charlottesville, VA
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Gonye EC, Dagli AV, Kumar NN, Clements RT, Xu W, Bayliss DA. Expression of endogenous epitope-tagged GPR4 in the mouse brain. eNeuro 2024; 11:ENEURO.0002-24.2024. [PMID: 38408869 DOI: 10.1523/eneuro.0002-24.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 02/13/2024] [Accepted: 02/17/2024] [Indexed: 02/28/2024] Open
Abstract
GPR4 is a proton-sensing G protein-coupled receptor implicated in many peripheral and central physiological processes. GPR4 expression has previously been assessed only via detection of the cognate transcript or indirectly, by use of fluorescent reporters. In this work, CRISPR/Cas9 knock-in technology was used to encode a hemagglutinin (HA) epitope tag within the endogenous locus of Gpr4 and visualize GPR4-HA in the mouse central nervous system using a specific, well characterized HA antibody; GPR4 expression was further verified by complementary Gpr4 mRNA detection. HA immunoreactivity was found in a limited set of brain regions, including in the retrotrapezoid nucleus (RTN), serotonergic raphe nuclei, medial habenula, lateral septum, and several thalamic nuclei. GPR4 expression was not restricted to cells of a specific neurochemical identity as it was observed in excitatory, inhibitory, and aminergic neuronal cell groups. HA immunoreactivity was not detected in brain vascular endothelium, despite clear expression of Gpr4 mRNA in endothelial cells. In the RTN, GPR4 expression was detected at the soma and in proximal dendrites along blood vessels and the ventral surface of the brainstem; HA immunoreactivity was not detected in RTN projections to two known target regions. This localization of GPR4 protein in mouse brain neurons corroborates putative sites of expression where its function has been previously implicated (e.g., CO2-regulated breathing by RTN), and provides a guide for where GPR4 could contribute to other CO2/H+ modulated brain functions. Finally, GPR4-HA animals provide a useful reagent for further study of GPR4 in other physiological processes outside of the brain.Significance Statement GPR4 is a proton-sensing G-protein coupled receptor whose expression is necessary for a number of diverse physiological processes including acid-base sensing in the kidney, immune function, and cancer progression. In the brain, GPR4 has been implicated in the hypercapnic ventilatory response mediated by brainstem neurons. While knockout studies in animals have clearly demonstrated its necessity for normal physiology, descriptions of GPR4 expression have been limited due to a lack of specific antibodies for use in mouse models. In this paper, we implemented a CRISPR/Cas9 knock-in approach to incorporate the coding sequence for a small epitope tag into the locus of GPR4. Using these mice, we were able to describe GPR4 protein expression directly for the first time.
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Affiliation(s)
- Elizabeth C Gonye
- University of Virginia, Department of Pharmacology, Charlottesville, VA, USA
| | - Alexandra V Dagli
- University of Virginia, Department of Pharmacology, Charlottesville, VA, USA
| | - Natasha N Kumar
- University of New South Wales Sydney, School of Biomedical Sciences, New South Wales, Australia
| | - Rachel T Clements
- University of Virginia, Department of Pharmacology, Charlottesville, VA, USA
| | - Wenhao Xu
- University of Virginia, Genetically Engineered Mouse Model Core, Charlottesville, VA, USA
| | - Douglas A Bayliss
- University of Virginia, Department of Pharmacology, Charlottesville, VA, USA
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Gonye EC, Bayliss DA. Criteria for central respiratory chemoreceptors: experimental evidence supporting current candidate cell groups. Front Physiol 2023; 14:1241662. [PMID: 37719465 PMCID: PMC10502317 DOI: 10.3389/fphys.2023.1241662] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 08/16/2023] [Indexed: 09/19/2023] Open
Abstract
An interoceptive homeostatic system monitors levels of CO2/H+ and provides a proportionate drive to respiratory control networks that adjust lung ventilation to maintain physiologically appropriate levels of CO2 and rapidly regulate tissue acid-base balance. It has long been suspected that the sensory cells responsible for the major CNS contribution to this so-called respiratory CO2/H+ chemoreception are located in the brainstem-but there is still substantial debate in the field as to which specific cells subserve the sensory function. Indeed, at the present time, several cell types have been championed as potential respiratory chemoreceptors, including neurons and astrocytes. In this review, we advance a set of criteria that are necessary and sufficient for definitive acceptance of any cell type as a respiratory chemoreceptor. We examine the extant evidence supporting consideration of the different putative chemoreceptor candidate cell types in the context of these criteria and also note for each where the criteria have not yet been fulfilled. By enumerating these specific criteria we hope to provide a useful heuristic that can be employed both to evaluate the various existing respiratory chemoreceptor candidates, and also to focus effort on specific experimental tests that can satisfy the remaining requirements for definitive acceptance.
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Affiliation(s)
- Elizabeth C. Gonye
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States
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Li K, Abbott SBG, Guyenet PG, Bayliss DA. JP-RL-2023-285396: Reply to 'Letter to the Editor' (JP-LE-2023-285385). J Physiol 2023; 601:4173-4175. [PMID: 37610165 DOI: 10.1113/jp285396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 08/24/2023] Open
Affiliation(s)
- Keyong Li
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
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Li K, Gonye EC, Stornetta RL, Bayliss CB, Yi G, Stornetta DS, Baca SM, Abbott SB, Guyenet PG, Bayliss DA. The astrocytic Na + -HCO 3 - cotransporter, NBCe1, is dispensable for respiratory chemosensitivity. J Physiol 2023; 601:3667-3686. [PMID: 37384821 PMCID: PMC10528273 DOI: 10.1113/jp284960] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Accepted: 06/02/2023] [Indexed: 07/01/2023] Open
Abstract
The interoceptive homeostatic mechanism that controls breathing, blood gases and acid-base balance in response to changes in CO2 /H+ is exquisitely sensitive, with convergent roles proposed for chemosensory brainstem neurons in the retrotrapezoid nucleus (RTN) and their supporting glial cells. For astrocytes, a central role for NBCe1, a Na+ -HCO3 - cotransporter encoded by Slc4a4, has been envisaged in multiple mechanistic models (i.e. underlying enhanced CO2 -induced local extracellular acidification or purinergic signalling). We tested these NBCe1-centric models by using conditional knockout mice in which Slc4a4 was deleted from astrocytes. In GFAP-Cre;Slc4a4fl/fl mice we found diminished expression of Slc4a4 in RTN astrocytes by comparison to control littermates, and a concomitant reduction in NBCe1-mediated current. Despite disrupted NBCe1 function in RTN-adjacent astrocytes from these conditional knockout mice, CO2 -induced activation of RTN neurons or astrocytes in vitro and in vivo, and CO2 -stimulated breathing, were indistinguishable from NBCe1-intact littermates; hypoxia-stimulated breathing and sighs were likewise unaffected. We obtained a more widespread deletion of NBCe1 in brainstem astrocytes by using tamoxifen-treated Aldh1l1-Cre/ERT2;Slc4a4fl/fl mice. Again, there was no difference in effects of CO2 or hypoxia on breathing or on neuron/astrocyte activation in NBCe1-deleted mice. These data indicate that astrocytic NBCe1 is not required for the respiratory responses to these chemoreceptor stimuli in mice, and that any physiologically relevant astrocytic contributions must involve NBCe1-independent mechanisms. KEY POINTS: The electrogenic NBCe1 transporter is proposed to mediate local astrocytic CO2 /H+ sensing that enables excitatory modulation of nearby retrotrapezoid nucleus (RTN) neurons to support chemosensory control of breathing. We used two different Cre mouse lines for cell-specific and/or temporally regulated deletion of the NBCe1 gene (Slc4a4) in astrocytes to test this hypothesis. In both mouse lines, Slc4a4 was depleted from RTN-associated astrocytes but CO2 -induced Fos expression (i.e. cell activation) in RTN neurons and local astrocytes was intact. Likewise, respiratory chemoreflexes evoked by changes in CO2 or O2 were unaffected by loss of astrocytic Slc4a4. These data do not support the previously proposed role for NBCe1 in respiratory chemosensitivity mediated by astrocytes.
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Affiliation(s)
- Keyong Li
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA, 22908
| | - Elizabeth C. Gonye
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA, 22908
| | - Ruth L. Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA, 22908
| | | | - Grace Yi
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA, 22908
| | - Daniel S. Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA, 22908
| | - Serapio M. Baca
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA, 22908
| | - Stephen B.G. Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA, 22908
| | - Patrice G. Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA, 22908
| | - Douglas A. Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA, 22908
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Souza GMPR, Stornetta DS, Shi Y, Lim E, Berry FE, Bayliss DA, Abbott SBG. Neuromedin B-Expressing Neurons in the Retrotrapezoid Nucleus Regulate Respiratory Homeostasis and Promote Stable Breathing in Adult Mice. J Neurosci 2023; 43:5501-5520. [PMID: 37290937 PMCID: PMC10376939 DOI: 10.1523/jneurosci.0386-23.2023] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/10/2023] Open
Abstract
Respiratory chemoreceptor activity encoding arterial Pco2 and Po2 is a critical determinant of ventilation. Currently, the relative importance of several putative chemoreceptor mechanisms for maintaining eupneic breathing and respiratory homeostasis is debated. Transcriptomic and anatomic evidence suggests that bombesin-related peptide Neuromedin-B (Nmb) expression identifies chemoreceptor neurons in the retrotrapezoid nucleus (RTN) that mediate the hypercapnic ventilatory response, but functional support is missing. In this study, we generated a transgenic Nmb-Cre mouse and used Cre-dependent cell ablation and optogenetics to test the hypothesis that RTN Nmb neurons are necessary for the CO2-dependent drive to breathe in adult male and female mice. Selective ablation of ∼95% of RTN Nmb neurons causes compensated respiratory acidosis because of alveolar hypoventilation, as well as profound breathing instability and respiratory-related sleep disruption. Following RTN Nmb lesion, mice were hypoxemic at rest and were prone to severe apneas during hyperoxia, suggesting that oxygen-sensitive mechanisms, presumably the peripheral chemoreceptors, compensate for the loss of RTN Nmb neurons. Interestingly, ventilation following RTN Nmb -lesion was unresponsive to hypercapnia, but behavioral responses to CO2 (freezing and avoidance) and the hypoxia ventilatory response were preserved. Neuroanatomical mapping shows that RTN Nmb neurons are highly collateralized and innervate the respiratory-related centers in the pons and medulla with a strong ipsilateral preference. Together, this evidence suggests that RTN Nmb neurons are dedicated to the respiratory effects of arterial Pco2/pH and maintain respiratory homeostasis in intact conditions and suggest that malfunction of these neurons could underlie the etiology of certain forms of sleep-disordered breathing in humans.SIGNIFICANCE STATEMENT Respiratory chemoreceptors stimulate neural respiratory motor output to regulate arterial Pco2 and Po2, thereby maintaining optimal gas exchange. Neurons in the retrotrapezoid nucleus (RTN) that express the bombesin-related peptide Neuromedin-B are proposed to be important in this process, but functional evidence has not been established. Here, we developed a transgenic mouse model and demonstrated that RTN neurons are fundamental for respiratory homeostasis and mediate the stimulatory effects of CO2 on breathing. Our functional and anatomic data indicate that Nmb-expressing RTN neurons are an integral component of the neural mechanisms that mediate CO2-dependent drive to breathe and maintain alveolar ventilation. This work highlights the importance of the interdependent and dynamic integration of CO2- and O2-sensing mechanisms in respiratory homeostasis of mammals.
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Affiliation(s)
- George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Daniel S Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Eunu Lim
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Faye E Berry
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908
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Moreira TS, Shi Y, Sobrinho CR, Milla BM, Soto-Perez J, Stornetta DS, Stornetta RL, Takakura AC, Mulkey DK, Bayliss DA. 5-HT7 receptors expressed in the mouse parafacial region are not required for respiratory chemosensitivity. FASEB J 2022. [PMID: 35551873 DOI: 10.1096/fasebj.2022.36.s1.r2540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A brainstem homeostatic system senses CO2 /H+ to regulate ventilation, blood gases and acid-base balance. Neurons of the retrotrapezoid nucleus (RTN) and medullary raphe are both implicated in this mechanism as respiratory chemosensors, but recent pharmacological work suggested that the CO2 /H+ -sensitivity of RTN neurons is mediated indirectly - by raphe-derived serotonin acting on 5-HT7 receptors. To investigate this further, we characterized Htr7 transcript expression in phenotypically identified RTN neurons using multiplex single cell qRT-PCR and RNAscope. Although present in multiple neurons in the parafacial region of the ventrolateral medulla, Htr7 expression was undetectable in most RTN neurons (Nmb+ /Phox2b+ ) concentrated in the densely packed cell group ventrolateral to the facial nucleus. Where detected, Htr7 expression was modest and often associated with RTN neurons that extend dorsolaterally to partially encircle the facial nucleus. These more dorsolateral Nmb+ /Htr7+ neurons tended to express high levels of Nmb and low levels of the intrinsic RTN proton detectors, Gpr4 and Kcnk5. In mouse brainstem slices, CO2 -stimulated firing in RTN neurons was mostly unaffected by a 5-HT7 receptor antagonist, SB269970 (n=11/12). At the whole animal level, microinjection of SB269970 into the RTN of conscious mice blocked respiratory stimulation by co-injected LP-44, a 5-HT7 receptor agonist, but had no effect on CO2 -stimulated breathing in those same mice. We conclude that Htr7 is expressed by a minor subset of RTN neurons with a molecular profile distinct from the established chemoreceptors and that 5-HT7 receptors have negligible effects on CO2 -evoked firing activity in RTN neurons or on CO2 -stimulated breathing in mice.
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Affiliation(s)
| | - Yingtang Shi
- Pharmacology, University of Virginia, Charlottesville, VA
| | | | - Brenda M Milla
- Physiology and Neurobiology, University of Connecticut, Storrs, CT
| | | | | | | | | | - Daniel K Mulkey
- Physiology and Neurobiology, University of Connecticut, Storrs, CT
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8
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Shi Y, Sobrinho CR, Soto-Perez J, Milla BM, Stornetta DS, Stornetta RL, Takakura AC, Mulkey DK, Moreira TS, Bayliss DA. 5-HT7 receptors expressed in the mouse parafacial region are not required for respiratory chemosensitivity. J Physiol 2022; 600:2789-2811. [PMID: 35385139 PMCID: PMC9167793 DOI: 10.1113/jp282279] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 03/23/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract A brainstem homeostatic system senses CO2/H+ to regulate ventilation, blood gases and acid–base balance. Neurons of the retrotrapezoid nucleus (RTN) and medullary raphe are both implicated in this mechanism as respiratory chemosensors, but recent pharmacological work suggested that the CO2/H+ sensitivity of RTN neurons is mediated indirectly, by raphe‐derived serotonin acting on 5‐HT7 receptors. To investigate this further, we characterized Htr7 transcript expression in phenotypically identified RTN neurons using multiplex single cell qRT‐PCR and RNAscope. Although present in multiple neurons in the parafacial region of the ventrolateral medulla, Htr7 expression was undetectable in most RTN neurons (Nmb+/Phox2b+) concentrated in the densely packed cell group ventrolateral to the facial nucleus. Where detected, Htr7 expression was modest and often associated with RTN neurons that extend dorsolaterally to partially encircle the facial nucleus. These dorsolateral Nmb+/Htr7+ neurons tended to express Nmb at high levels and the intrinsic RTN proton detectors Gpr4 and Kcnk5 at low levels. In mouse brainstem slices, CO2‐stimulated firing in RTN neurons was mostly unaffected by a 5‐HT7 receptor antagonist, SB269970 (n = 11/13). At the whole animal level, microinjection of SB269970 into the RTN of conscious mice blocked respiratory stimulation by co‐injected LP‐44, a 5‐HT7 receptor agonist, but had no effect on CO2‐stimulated breathing in those same mice. We conclude that Htr7 is expressed by a minor subset of RTN neurons with a molecular profile distinct from the established chemoreceptors and that 5‐HT7 receptors have negligible effects on CO2‐evoked firing activity in RTN neurons or on CO2‐stimulated breathing in mice. Key points Neurons of the retrotrapezoid nucleus (RTN) are intrinsic CO2/H+ chemosensors and serve as an integrative excitatory hub for control of breathing. Serotonin can activate RTN neurons, in part via 5‐HT7 receptors, and those effects have been implicated in conferring an indirect CO2 sensitivity. Multiple single cell molecular approaches revealed low levels of 5‐HT7 receptor transcript expression restricted to a limited population of RTN neurons. Pharmacological experiments showed that 5‐HT7 receptors in RTN are not required for CO2/H+‐stimulation of RTN neuronal activity or CO2‐stimulated breathing. These data do not support a role for 5‐HT7 receptors in respiratory chemosensitivity mediated by RTN neurons.
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Affiliation(s)
- Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Cleyton R Sobrinho
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Jaseph Soto-Perez
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Brenda M Milla
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Daniel S Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Daniel K Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
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Abstract
Brain PCO2 is sensed primarily via changes in [H+]. Small pH changes are detected in the medulla oblongata and trigger breathing adjustments that help maintain arterial PCO2 constant. Larger perturbations of brain CO2/H+, possibly also sensed elsewhere in the CNS, elicit arousal, dyspnea, and stress, and cause additional breathing modifications. The retrotrapezoid nucleus (RTN), a rostral medullary cluster of glutamatergic neurons identified by coexpression of Phoxb and Nmb transcripts, is the lynchpin of the central respiratory chemoreflex. RTN regulates breathing frequency, inspiratory amplitude, and active expiration. It is exquisitely responsive to acidosis in vivo and maintains breathing autorhythmicity during quiet waking, slow-wave sleep, and anesthesia. The RTN response to [H+] is partly an intrinsic neuronal property mediated by proton sensors TASK-2 and GPR4 and partly a paracrine effect mediated by astrocytes and the vasculature. The RTN also receives myriad excitatory or inhibitory synaptic inputs including from [H+]-responsive neurons (e.g., serotonergic). RTN is silenced by moderate hypoxia. RTN inactivity (periodic or sustained) contributes to periodic breathing and, likely, to central sleep apnea. RTN development relies on transcription factors Egr2, Phox2b, Lbx1, and Atoh1. PHOX2B mutations cause congenital central hypoventilation syndrome; they impair RTN development and consequently the central respiratory chemoreflex.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States.
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States
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10
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Medina CB, Chiu YH, Stremska ME, Lucas CD, Poon I, Tung KS, Elliott MR, Desai B, Lorenz UM, Bayliss DA, Ravichandran KS. Pannexin 1 channels facilitate communication between T cells to restrict the severity of airway inflammation. Immunity 2021; 54:1715-1727.e7. [PMID: 34283971 PMCID: PMC8363584 DOI: 10.1016/j.immuni.2021.06.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/21/2021] [Accepted: 06/21/2021] [Indexed: 01/14/2023]
Abstract
Allergic airway inflammation is driven by type-2 CD4+ T cell inflammatory responses. We uncover an immunoregulatory role for the nucleotide release channel, Panx1, in T cell crosstalk during airway disease. Inverse correlations between Panx1 and asthmatics and our mouse models revealed the necessity, specificity, and sufficiency of Panx1 in T cells to restrict inflammation. Global Panx1-/- mice experienced exacerbated airway inflammation, and T-cell-specific deletion phenocopied Panx1-/- mice. A transgenic designed to re-express Panx1 in T cells reversed disease severity in global Panx1-/- mice. Panx1 activation occurred in pro-inflammatory T effector (Teff) and inhibitory T regulatory (Treg) cells and mediated the extracellular-nucleotide-based Treg-Teff crosstalk required for suppression of Teff cell proliferation. Mechanistic studies identified a Salt-inducible kinase-dependent phosphorylation of Panx1 serine 205 important for channel activation. A genetically targeted mouse expressing non-phosphorylatable Panx1S205A phenocopied the exacerbated inflammation in Panx1-/- mice. These data identify Panx1-dependent Treg:Teff cell communication in restricting airway disease.
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Affiliation(s)
- Christopher B Medina
- Center for Cell Clearance, University of Virginia, Charlottesville, VA 22908, USA; Departments of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA; Institute of Biotechnology and Department of Medical Science, National Tsing Hua University, Hsinchu, 30071, Taiwan
| | - Marta E Stremska
- Departments of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Christopher D Lucas
- Center for Cell Clearance, University of Virginia, Charlottesville, VA 22908, USA
| | - Ivan Poon
- Department of Biochemistry and Genetics, La Trobe University, Melbourne, VIC 3083, Australia
| | - Kenneth S Tung
- Departments of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA; Carter Immunology Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Michael R Elliott
- Center for Cell Clearance, University of Virginia, Charlottesville, VA 22908, USA; Departments of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Bimal Desai
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ulrike M Lorenz
- Departments of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA; Carter Immunology Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Kodi S Ravichandran
- Center for Cell Clearance, University of Virginia, Charlottesville, VA 22908, USA; Departments of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA; Carter Immunology Center, University of Virginia, Charlottesville, VA 22908, USA; VIB/UGent Inflammation Research Centre and the Department of Biomedical Molecular Biology, Ghent University, 9000 Ghent, Belgium.
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11
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Chiu YH, Medina CB, Doyle CA, Zhou M, Narahari AK, Sandilos JK, Gonye EC, Gao HY, Guo SY, Parlak M, Lorenz UM, Conrads TP, Desai BN, Ravichandran KS, Bayliss DA. Deacetylation as a receptor-regulated direct activation switch for pannexin channels. Nat Commun 2021; 12:4482. [PMID: 34301959 PMCID: PMC8302610 DOI: 10.1038/s41467-021-24825-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Accepted: 07/12/2021] [Indexed: 02/07/2023] Open
Abstract
Activation of Pannexin 1 (PANX1) ion channels causes release of intercellular signaling molecules in a variety of (patho)physiological contexts. PANX1 can be activated by G protein-coupled receptors (GPCRs), including α1-adrenergic receptors (α1-ARs), but how receptor engagement leads to channel opening remains unclear. Here, we show that GPCR-mediated PANX1 activation can occur via channel deacetylation. We find that α1-AR-mediated activation of PANX1 channels requires Gαq but is independent of phospholipase C or intracellular calcium. Instead, α1-AR-mediated PANX1 activation involves RhoA, mammalian diaphanous (mDia)-related formin, and a cytosolic lysine deacetylase activated by mDia - histone deacetylase 6. HDAC6 associates with PANX1 and activates PANX1 channels, even in excised membrane patches, suggesting direct deacetylation of PANX1. Substitution of basally-acetylated intracellular lysine residues identified on PANX1 by mass spectrometry either prevents HDAC6-mediated activation (K140/409Q) or renders the channels constitutively active (K140R). These data define a non-canonical RhoA-mDia-HDAC6 signaling pathway for GαqPCR activation of PANX1 channels and uncover lysine acetylation-deacetylation as an ion channel silencing-activation mechanism.
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Affiliation(s)
- Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.
- Institute of Biotechnology, National Tsing Hua University, Hsinchu, Taiwan.
- Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan.
| | - Christopher B Medina
- Department of Microbiology, Immunology & Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Catherine A Doyle
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Ming Zhou
- Inova Center for Personalized Health, Inova Schar Cancer Institute, Fairfax, VA, USA
| | - Adishesh K Narahari
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Joanna K Sandilos
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Elizabeth C Gonye
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Hong-Yu Gao
- Institute of Biotechnology, National Tsing Hua University, Hsinchu, Taiwan
| | - Shih Yi Guo
- Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Mahmut Parlak
- Department of Microbiology, Immunology & Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Ulrike M Lorenz
- Department of Microbiology, Immunology & Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Thomas P Conrads
- Inova Center for Personalized Health, Inova Schar Cancer Institute, Fairfax, VA, USA
| | - Bimal N Desai
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology & Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.
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12
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Li K, Abbott SBG, Shi Y, Eggan P, Gonye EC, Bayliss DA. TRPM4 mediates a subthreshold membrane potential oscillation in respiratory chemoreceptor neurons that drives pacemaker firing and breathing. Cell Rep 2021; 34:108714. [PMID: 33535052 PMCID: PMC7888550 DOI: 10.1016/j.celrep.2021.108714] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 12/04/2020] [Accepted: 01/12/2021] [Indexed: 12/01/2022] Open
Abstract
Brainstem networks that control regular tidal breathing depend on excitatory drive, including from tonically active, CO2/H+-sensitive neurons of the retrotrapezoid nucleus (RTN). Here, we examine intrinsic ionic mechanisms underlying the metronomic firing activity characteristic of RTN neurons. In mouse brainstem slices, large-amplitude membrane potential oscillations are evident in synaptically isolated RTN neurons after blocking action potentials. The voltage-dependent oscillations are abolished by sodium replacement; blocking calcium channels (primarily L-type); chelating intracellular Ca2+; and inhibiting TRPM4, a Ca2+-dependent cationic channel. Likewise, oscillation voltage waveform currents are sensitive to calcium and TRPM4 channel blockers. Extracellular acidification and serotonin (5-HT) evoke membrane depolarization that augments TRPM4-dependent oscillatory activity and action potential discharge. Finally, inhibition of TRPM4 channels in the RTN of anesthetized mice reduces central respiratory output. These data implicate TRPM4 in a subthreshold oscillation that supports the pacemaker-like firing of RTN neurons required for basal, CO2-stimulated, and state-dependent breathing.
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Affiliation(s)
- Keyong Li
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Pierce Eggan
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Elizabeth C Gonye
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA.
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13
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Narahari AK, Kreutzberger AJB, Gaete PS, Chiu YH, Leonhardt SA, Medina CB, Jin X, Oleniacz PW, Kiessling V, Barrett PQ, Ravichandran KS, Yeager M, Contreras JE, Tamm LK, Bayliss DA. ATP and large signaling metabolites flux through caspase-activated Pannexin 1 channels. eLife 2021; 10:e64787. [PMID: 33410749 PMCID: PMC7806264 DOI: 10.7554/elife.64787] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/05/2021] [Indexed: 12/16/2022] Open
Abstract
Pannexin 1 (Panx1) is a membrane channel implicated in numerous physiological and pathophysiological processes via its ability to support release of ATP and other cellular metabolites for local intercellular signaling. However, to date, there has been no direct demonstration of large molecule permeation via the Panx1 channel itself, and thus the permselectivity of Panx1 for different molecules remains unknown. To address this, we expressed, purified, and reconstituted Panx1 into proteoliposomes and demonstrated that channel activation by caspase cleavage yields a dye-permeable pore that favors flux of anionic, large-molecule permeants (up to ~1 kDa). Large cationic molecules can also permeate the channel, albeit at a much lower rate. We further show that Panx1 channels provide a molecular pathway for flux of ATP and other anionic (glutamate) and cationic signaling metabolites (spermidine). These results verify large molecule permeation directly through caspase-activated Panx1 channels that can support their many physiological roles.
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Affiliation(s)
- Adishesh K Narahari
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | - Alex JB Kreutzberger
- Department of Molecular Physiology and Biological Physics, University of VirginiaCharlottesvilleUnited States
| | - Pablo S Gaete
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers New Jersey Medical SchoolNewarkUnited States
| | - Yu-Hsin Chiu
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | - Susan A Leonhardt
- Department of Molecular Physiology and Biological Physics, University of VirginiaCharlottesvilleUnited States
| | - Christopher B Medina
- Department of Microbiology, Immunology, and Cancer Biology, University of VirginiaCharlottesvilleUnited States
| | - Xueyao Jin
- Department of Molecular Physiology and Biological Physics, University of VirginiaCharlottesvilleUnited States
| | - Patrycja W Oleniacz
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | - Volker Kiessling
- Department of Molecular Physiology and Biological Physics, University of VirginiaCharlottesvilleUnited States
| | - Paula Q Barrett
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer Biology, University of VirginiaCharlottesvilleUnited States
| | - Mark Yeager
- Department of Molecular Physiology and Biological Physics, University of VirginiaCharlottesvilleUnited States
| | - Jorge E Contreras
- Department of Pharmacology, Physiology, and Neuroscience, Rutgers New Jersey Medical SchoolNewarkUnited States
| | - Lukas K Tamm
- Department of Molecular Physiology and Biological Physics, University of VirginiaCharlottesvilleUnited States
| | - Douglas A Bayliss
- Department of Pharmacology, University of VirginiaCharlottesvilleUnited States
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14
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Shi Y, Stornetta DS, Reklow RJ, Sahu A, Wabara Y, Nguyen A, Li K, Zhang Y, Perez-Reyes E, Ross RA, Lowell BB, Stornetta RL, Funk GD, Guyenet PG, Bayliss DA. A brainstem peptide system activated at birth protects postnatal breathing. Nature 2021; 589:426-430. [PMID: 33268898 PMCID: PMC7855323 DOI: 10.1038/s41586-020-2991-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 09/29/2020] [Indexed: 01/29/2023]
Abstract
Among numerous challenges encountered at the beginning of extrauterine life, the most celebrated is the first breath that initiates a life-sustaining motor activity1. The neural systems that regulate breathing are fragile early in development, and it is not clear how they adjust to support breathing at birth. Here we identify a neuropeptide system that becomes activated immediately after birth and supports breathing. Mice that lack PACAP selectively in neurons of the retrotrapezoid nucleus (RTN) displayed increased apnoeas and blunted CO2-stimulated breathing; re-expression of PACAP in RTN neurons corrected these breathing deficits. Deletion of the PACAP receptor PAC1 from the pre-Bötzinger complex-an RTN target region responsible for generating the respiratory rhythm-phenocopied the breathing deficits observed after RTN deletion of PACAP, and suppressed PACAP-evoked respiratory stimulation in the pre-Bötzinger complex. Notably, a postnatal burst of PACAP expression occurred in RTN neurons precisely at the time of birth, coinciding with exposure to the external environment. Neonatal mice with deletion of PACAP in RTN neurons displayed increased apnoeas that were further exacerbated by changes in ambient temperature. Our findings demonstrate that well-timed PACAP expression by RTN neurons provides an important supplementary respiratory drive immediately after birth and reveal key molecular components of a peptidergic neural circuit that supports breathing at a particularly vulnerable period in life.
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Affiliation(s)
- Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Daniel S. Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Robert J. Reklow
- Department of Physiology, Women & Children’s Health Research Institute, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Alisha Sahu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Yvonne Wabara
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Ashley Nguyen
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Keyong Li
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Yong Zhang
- Department of Physiology, Women & Children’s Health Research Institute, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Rachel A. Ross
- Beth Israel Deaconess Medical Center, Harvard University, Boston, MA, USA,McLean Hospital, Department of Psychiatry, Harvard Medical School, Belmont, MA, USA
| | - Bradford B. Lowell
- Beth Israel Deaconess Medical Center, Harvard University, Boston, MA, USA
| | - Ruth L. Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Gregory D. Funk
- Department of Physiology, Women & Children’s Health Research Institute, Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Patrice G. Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
| | - Douglas A. Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia, USA
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15
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Barrett PQ, Guagliardo NA, Bayliss DA. Ion Channel Function and Electrical Excitability in the Zona Glomerulosa: A Network Perspective on Aldosterone Regulation. Annu Rev Physiol 2020; 83:451-475. [PMID: 33176563 DOI: 10.1146/annurev-physiol-030220-113038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Aldosterone excess is a pathogenic factor in many hypertensive disorders. The discovery of numerous somatic and germline mutations in ion channels in primary hyperaldosteronism underscores the importance of plasma membrane conductances in determining the activation state of zona glomerulosa (zG) cells. Electrophysiological recordings describe an electrically quiescent behavior for dispersed zG cells. Yet, emerging data indicate that in native rosette structures in situ, zG cells are electrically excitable, generating slow periodic voltage spikes and coordinated bursts of Ca2+ oscillations. We revisit data to understand how a multitude of conductances may underlie voltage/Ca2+ oscillations, recognizing that zG layer self-renewal and cell heterogeneity may complicate this task. We review recent data to understand rosette architecture and apply maxims derived from computational network modeling to understand rosette function. The challenge going forward is to uncover how the rosette orchestrates the behavior of a functional network of conditional oscillators to control zG layer performance and aldosterone secretion.
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Affiliation(s)
- Paula Q Barrett
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA; , ,
| | - Nick A Guagliardo
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA; , ,
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA; , ,
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16
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DeLalio LJ, Masati E, Mendu S, Ruddiman CA, Yang Y, Johnstone SR, Milstein JA, Keller TCS, Weaver RB, Guagliardo NA, Best AK, Ravichandran KS, Bayliss DA, Sequeira-Lopez MLS, Sonkusare SN, Shu XH, Desai B, Barrett PQ, Le TH, Gomez RA, Isakson BE. Pannexin 1 channels in renin-expressing cells influence renin secretion and blood pressure homeostasis. Kidney Int 2020; 98:630-644. [PMID: 32446934 PMCID: PMC7483468 DOI: 10.1016/j.kint.2020.04.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 03/29/2020] [Accepted: 04/02/2020] [Indexed: 02/07/2023]
Abstract
Kidney function and blood pressure homeostasis are regulated by purinergic signaling mechanisms. These autocrine/paracrine signaling pathways are initiated by the release of cellular ATP, which influences kidney hemodynamics and steady-state renin secretion from juxtaglomerular cells. However, the mechanism responsible for ATP release that supports tonic inputs to juxtaglomerular cells and regulates renin secretion remains unclear. Pannexin 1 (Panx1) channels localize to both afferent arterioles and juxtaglomerular cells and provide a transmembrane conduit for ATP release and ion permeability in the kidney and the vasculature. We hypothesized that Panx1 channels in renin-expressing cells regulate renin secretion in vivo. Using a renin cell-specific Panx1 knockout model, we found that male Panx1 deficient mice exhibiting a heightened activation of the renin-angiotensin-aldosterone system have markedly increased plasma renin and aldosterone concentrations, and elevated mean arterial pressure with altered peripheral hemodynamics. Following ovariectomy, female mice mirrored the male phenotype. Furthermore, constitutive Panx1 channel activity was observed in As4.1 renin-secreting cells, whereby Panx1 knockdown reduced extracellular ATP accumulation, lowered basal intracellular calcium concentrations and recapitulated a hyper-secretory renin phenotype. Moreover, in response to stress stimuli that lower blood pressure, Panx1-deficient mice exhibited aberrant "renin recruitment" as evidenced by reactivation of renin expression in pre-glomerular arteriolar smooth muscle cells. Thus, renin-cell Panx1 channels suppress renin secretion and influence adaptive renin responses when blood pressure homeostasis is threatened.
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Affiliation(s)
- Leon J DeLalio
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA; Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Ester Masati
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Suresh Mendu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Claire A Ruddiman
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA; Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Yang Yang
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA; Department of Pharmacology, Dalian Medical University, Dalian, China
| | - Scott R Johnstone
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Jenna A Milstein
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - T C Stevenson Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA; Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Rachel B Weaver
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Nick A Guagliardo
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Angela K Best
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Maria Luisa S Sequeira-Lopez
- Pediatric Center of Excellence in Nephrology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Swapnil N Sonkusare
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA; Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Xiaohong H Shu
- Department of Pharmacology, Dalian Medical University, Dalian, China
| | - Bimal Desai
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Paula Q Barrett
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Thu H Le
- Department of Medicine, Division of Nephrology, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - R Ariel Gomez
- Pediatric Center of Excellence in Nephrology, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA; Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA.
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17
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Narahari AK, Kreutzberger AJ, Leonhardt S, Jin X, Pauchard P, Medina CB, Kiessling V, Ravichandran K, Contreras JE, Tamm LK, Yeager M, Bayliss DA. Permeation Properties of Purified Pannexin 1 Channels in Proteoliposomes. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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18
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Guagliardo NA, Yao J, Stipes EJ, Cechova S, Le TH, Bayliss DA, Breault DT, Barrett PQ. Adrenal Tissue-Specific Deletion of TASK Channels Causes Aldosterone-Driven Angiotensin II-Independent Hypertension. Hypertension 2019; 73:407-414. [PMID: 30580687 PMCID: PMC6326871 DOI: 10.1161/hypertensionaha.118.11962] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The renin-angiotensin system tightly controls aldosterone synthesis. Dysregulation is evident in hypertension (primary aldosteronism), low renin, and resistant hypertension) but also can exist in normotension. Whether chronic, mild aldosterone autonomy can elicit hypertension remains untested. Previously, we reported that global genetic deletion of 2 pore-domain TWIK-relative acid-sensitive potassium channels, TASK-1 and TASK-3, from mice produces striking aldosterone excess, low renin, and hypertension. Here, we deleted TASK-1 and TASK-3 channels selectively from zona glomerulosa cells and generated a model of mild aldosterone autonomy with attendant hypertension that is aldosterone-driven and Ang II (angiotensin II)-independent. This study shows that a zona glomerulosa-specific channel defect can produce mild autonomous hyperaldosteronism sufficient to cause chronic blood pressure elevation.
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Affiliation(s)
- Nick A Guagliardo
- From the Department of Pharmacology (N.A.G., J.Y., E.J.S., D.A.B, P.Q.B.), University of Virginia School of Medicine, Charlottesville
| | - Junlan Yao
- From the Department of Pharmacology (N.A.G., J.Y., E.J.S., D.A.B, P.Q.B.), University of Virginia School of Medicine, Charlottesville
| | - Eric J Stipes
- From the Department of Pharmacology (N.A.G., J.Y., E.J.S., D.A.B, P.Q.B.), University of Virginia School of Medicine, Charlottesville
| | - Sylvia Cechova
- Division of Nephrology, Department of Medicine (S.C., T.H.L.), University of Virginia School of Medicine, Charlottesville
| | - Thu H Le
- Division of Nephrology, Department of Medicine (S.C., T.H.L.), University of Virginia School of Medicine, Charlottesville
| | - Douglas A Bayliss
- From the Department of Pharmacology (N.A.G., J.Y., E.J.S., D.A.B, P.Q.B.), University of Virginia School of Medicine, Charlottesville
| | - David T Breault
- Department of Pediatrics/Division of Endocrinology, Boston Children's Hospital, Harvard Medical School, MA (D.T.B.)
| | - Paula Q Barrett
- From the Department of Pharmacology (N.A.G., J.Y., E.J.S., D.A.B, P.Q.B.), University of Virginia School of Medicine, Charlottesville
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19
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Guyenet PG, Stornetta RL, Souza GMPR, Abbott SBG, Shi Y, Bayliss DA. The Retrotrapezoid Nucleus: Central Chemoreceptor and Regulator of Breathing Automaticity. Trends Neurosci 2019; 42:807-824. [PMID: 31635852 DOI: 10.1016/j.tins.2019.09.002] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/28/2019] [Accepted: 09/05/2019] [Indexed: 12/15/2022]
Abstract
The ventral surface of the rostral medulla oblongata has been suspected since the 1960s to harbor central respiratory chemoreceptors [i.e., acid-activated neurons that regulate breathing to maintain a constant arterial PCO2 (PaCO2)]. The key neurons, a.k.a. the retrotrapezoid nucleus (RTN), have now been identified. In this review we describe their transcriptome, developmental lineage, and anatomical projections. We also review their contribution to CO2 homeostasis and to the regulation of breathing automaticity during sleep and wake. Finally, we discuss several mechanisms that contribute to the activation of RTN neurons by CO2in vivo: cell-autonomous effects of protons; paracrine effects of pH mediated by surrounding astrocytes and blood vessels; and excitatory inputs from other CO2-responsive CNS neurons.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA.
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
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20
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Bayliss DA, Czirják G, Enyedi P, Goldstein SA, Lesage F, Minor, Jr. DL, Plant LD, Sepúlveda F, Winn BT. Two P domain potassium channels (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database. ACTA ACUST UNITED AC 2019. [DOI: 10.2218/gtopdb/f79/2019.4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The 4TM family of K channels mediate many of the background potassium currents observed in native cells. They are open across the physiological voltage-range and are regulated by a wide array of neurotransmitters and biochemical mediators. The pore-forming α-subunit contains two pore loop (P) domains and two subunits assemble to form one ion conduction pathway lined by four P domains. It is important to note that single channels do not have two pores but that each subunit has two P domains in its primary sequence; hence the name two P domain, or K2P channels (and not two-pore channels). Some of the K2P subunits can form heterodimers across subfamilies (e.g. K2P3.1 with K2P9.1). The nomenclature of 4TM K channels in the literature is still a mixture of IUPHAR and common names. The suggested division into subfamilies, described in the More detailed introduction, is based on similarities in both structural and functional properties within subfamilies and this explains the "common abbreviation" nomenclature in the tables below.
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Sharma AK, Charles EJ, Zhao Y, Narahari AK, Baderdinni PK, Good ME, Lorenz UM, Kron IL, Bayliss DA, Ravichandran KS, Isakson BE, Laubach VE. Pannexin-1 channels on endothelial cells mediate vascular inflammation during lung ischemia-reperfusion injury. Am J Physiol Lung Cell Mol Physiol 2018; 315:L301-L312. [PMID: 29745255 PMCID: PMC6139659 DOI: 10.1152/ajplung.00004.2018] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 04/17/2018] [Accepted: 05/02/2018] [Indexed: 12/31/2022] Open
Abstract
Ischemia-reperfusion (I/R) injury (IRI), which involves inflammation, vascular permeability, and edema, remains a major challenge after lung transplantation. Pannexin-1 (Panx1) channels modulate cellular ATP release during inflammation. This study tests the hypothesis that endothelial Panx1 is a key mediator of vascular inflammation and edema after I/R and that IRI can be blocked by Panx1 antagonism. A murine hilar ligation model of IRI was used whereby left lungs underwent 1 h of ischemia and 2 h of reperfusion. Treatment of wild-type mice with Panx1 inhibitors (carbenoxolone or probenecid) significantly attenuated I/R-induced pulmonary dysfunction, edema, cytokine production, and neutrophil infiltration versus vehicle-treated mice. In addition, VE-Cad-CreERT2+/Panx1fl/fl mice (tamoxifen-inducible deletion of Panx1 in vascular endothelium) treated with tamoxifen were significantly protected from IRI (reduced dysfunction, endothelial permeability, edema, proinflammatory cytokines, and neutrophil infiltration) versus vehicle-treated mice. Furthermore, extracellular ATP levels in bronchoalveolar lavage fluid is Panx1-mediated after I/R as it was markedly attenuated by Panx1 antagonism in wild-type mice and by endothelial-specific Panx1 deficiency. Panx1 gene expression in lungs after I/R was also significantly elevated compared with sham. In vitro experiments demonstrated that TNF-α and/or hypoxia-reoxygenation induced ATP release from lung microvascular endothelial cells, which was attenuated by Panx1 inhibitors. This study is the first, to our knowledge, to demonstrate that endothelial Panx1 plays a key role in mediating vascular permeability, inflammation, edema, leukocyte infiltration, and lung dysfunction after I/R. Pharmacological antagonism of Panx1 activity may be a novel therapeutic strategy to prevent IRI and primary graft dysfunction after lung transplantation.
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Affiliation(s)
- Ashish K Sharma
- Department of Surgery, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Eric J Charles
- Department of Surgery, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Yunge Zhao
- Department of Surgery, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Adishesh K Narahari
- Department of Pharmacology, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Pranav K Baderdinni
- Department of Pharmacology, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Miranda E Good
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Ulrike M Lorenz
- Department of Microbiology, Immunology, and Cancer, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Irving L Kron
- Department of Surgery, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Victor E Laubach
- Department of Surgery, University of Virginia School of Medicine , Charlottesville, Virginia
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Good ME, Chiu YH, Poon IKH, Jaffe IZ, Bayliss DA, Isakson BE, Ravichandran KS. Response by Good et al to Letter Regarding Article, "Pannexin-1 Channels as an Unexpected New Target of the Antihypertensive Drug Spironolactone". Circ Res 2018; 122:e88-e89. [PMID: 29798905 DOI: 10.1161/circresaha.118.313080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Miranda E Good
- Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville
| | - Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville
| | - Ivan K H Poon
- Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia
| | - Iris Z Jaffe
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville
| | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville
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Guyenet PG, Bayliss DA, Stornetta RL, Kanbar R, Shi Y, Holloway BB, Souza GMPR, Basting TM, Abbott SBG, Wenker IC. Interdependent feedback regulation of breathing by the carotid bodies and the retrotrapezoid nucleus. J Physiol 2017; 596:3029-3042. [PMID: 29168167 DOI: 10.1113/jp274357] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 11/02/2017] [Indexed: 12/13/2022] Open
Abstract
The retrotrapezoid nucleus (RTN) regulates breathing in a CO2 - and state-dependent manner. RTN neurons are glutamatergic and innervate principally the respiratory pattern generator; they regulate multiple aspects of breathing, including active expiration, and maintain breathing automaticity during non-REM sleep. RTN neurons encode arterial PCO2 /pH via cell-autonomous and paracrine mechanisms, and via input from other CO2 -responsive neurons. In short, RTN neurons are a pivotal structure for breathing automaticity and arterial PCO2 homeostasis. The carotid bodies stimulate the respiratory pattern generator directly and indirectly by activating RTN via a neuronal projection originating within the solitary tract nucleus. The indirect pathway operates under normo- or hypercapnic conditions; under respiratory alkalosis (e.g. hypoxia) RTN neurons are silent and the excitatory input from the carotid bodies is suppressed. Also, silencing RTN neurons optogenetically quickly triggers a compensatory increase in carotid body activity. Thus, in conscious mammals, breathing is subject to a dual and interdependent feedback regulation by chemoreceptors. Depending on the circumstance, the activity of the carotid bodies and that of RTN vary in the same or the opposite directions, producing additive or countervailing effects on breathing. These interactions are mediated either via changes in blood gases or by brainstem neuronal connections, but their ultimate effect is invariably to minimize arterial PCO2 fluctuations. We discuss the potential relevance of this dual chemoreceptor feedback to cardiorespiratory abnormalities present in diseases in which the carotid bodies are hyperactive at rest, e.g. essential hypertension, obstructive sleep apnoea and heart failure.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Roy Kanbar
- Department of Pharmaceutical Sciences, Lebanese American University, Beyrouth, Lebanon
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Benjamin B Holloway
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - George M P R Souza
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Tyler M Basting
- Department of Pharmacology & Experimental Therapeutics, Louisiana State University, New Orleans, Louisiana 70112, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ian C Wenker
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
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24
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Good ME, Chiu YH, Poon IKH, Medina CB, Butcher JT, Mendu SK, DeLalio LJ, Lohman AW, Leitinger N, Barrett E, Lorenz UM, Desai BN, Jaffe IZ, Bayliss DA, Isakson BE, Ravichandran KS. Pannexin 1 Channels as an Unexpected New Target of the Anti-Hypertensive Drug Spironolactone. Circ Res 2017; 122:606-615. [PMID: 29237722 DOI: 10.1161/circresaha.117.312380] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 12/06/2017] [Accepted: 12/12/2017] [Indexed: 12/16/2022]
Abstract
RATIONALE Resistant hypertension is a major health concern with unknown cause. Spironolactone is an effective antihypertensive drug, especially for patients with resistant hypertension, and is considered by the World Health Organization as an essential medication. Although spironolactone can act at the mineralocorticoid receptor (MR; NR3C2), there is increasing evidence of MR-independent effects of spironolactone. OBJECTIVE Here, we detail the unexpected discovery that Panx1 (pannexin 1) channels could be a relevant in vivo target of spironolactone. METHODS AND RESULTS First, we identified spironolactone as a potent inhibitor of Panx1 in an unbiased small molecule screen, which was confirmed by electrophysiological analysis. Next, spironolactone inhibited α-adrenergic vasoconstriction in arterioles from mice and hypertensive humans, an effect dependent on smooth muscle Panx1, but independent of the MR NR3C2. Last, spironolactone acutely lowered blood pressure, which was dependent on smooth muscle cell expression of Panx1 and independent of NR3C2. This effect, however, was restricted to steroidal MR antagonists as a nonsteroidal MR antagonist failed to reduced blood pressure. CONCLUSIONS These data suggest new therapeutic modalities for resistant hypertension based on Panx1 inhibition.
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Affiliation(s)
- Miranda E Good
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Yu-Hsin Chiu
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Ivan K H Poon
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Christopher B Medina
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Joshua T Butcher
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Suresh K Mendu
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Leon J DeLalio
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Alexander W Lohman
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Norbert Leitinger
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Eugene Barrett
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Ulrike M Lorenz
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Bimal N Desai
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Iris Z Jaffe
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Douglas A Bayliss
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Brant E Isakson
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.).
| | - Kodi S Ravichandran
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
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Chiu YH, Schappe MS, Desai BN, Bayliss DA. Revisiting multimodal activation and channel properties of Pannexin 1. J Gen Physiol 2017; 150:19-39. [PMID: 29233884 PMCID: PMC5749114 DOI: 10.1085/jgp.201711888] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 11/09/2017] [Indexed: 12/23/2022] Open
Abstract
Pannexin 1 (Panx1) forms plasma membrane ion channels that are widely expressed throughout the body. Panx1 activation results in the release of nucleotides such as adenosine triphosphate and uridine triphosphate. Thus, these channels have been implicated in diverse physiological and pathological functions associated with purinergic signaling, such as apoptotic cell clearance, blood pressure regulation, neuropathic pain, and excitotoxicity. In light of this, substantial attention has been directed to understanding the mechanisms that regulate Panx1 channel expression and activation. Here we review accumulated evidence for the various activation mechanisms described for Panx1 channels and, where possible, the unitary channel properties associated with those forms of activation. We also emphasize current limitations in studying Panx1 channel function and propose potential directions to clarify the exciting and expanding roles of Panx1 channels.
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Affiliation(s)
- Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Michael S Schappe
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Bimal N Desai
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
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26
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Yao J, McHedlishvili D, McIntire WE, Guagliardo NA, Erisir A, Coburn CA, Santarelli VP, Bayliss DA, Barrett PQ. Functional TASK-3-Like Channels in Mitochondria of Aldosterone-Producing Zona Glomerulosa Cells. Hypertension 2017. [PMID: 28630209 DOI: 10.1161/hypertensionaha.116.08871] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ca2+ drives aldosterone synthesis in the cytosolic and mitochondrial compartments of the adrenal zona glomerulosa cell. Membrane potential across each of these compartments regulates the amplitude of the Ca2+ signal; yet, only plasma membrane ion channels and their role in regulating cell membrane potential have garnered investigative attention as pathological causes of human hyperaldosteronism. Previously, we reported that genetic deletion of TASK-3 channels (tandem pore domain acid-sensitive K+ channels) from mice produces aldosterone excess in the absence of a change in the cell membrane potential of zona glomerulosa cells. Here, we report using yeast 2-hybrid, immunoprecipitation, and electron microscopic analyses that TASK-3 channels are resident in mitochondria, where they regulate mitochondrial morphology, mitochondrial membrane potential, and aldosterone production. This study provides proof of principle that mitochondrial K+ channels, by modulating inner mitochondrial membrane morphology and mitochondrial membrane potential, have the ability to play a pathological role in aldosterone dysregulation in steroidogenic cells.
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Affiliation(s)
- Junlan Yao
- From the Departments of Pharmacology (J.Y., D.M., W.E.M., N.A.G., D.A.B., P.Q.B.) and Psychology (A.E.), University of Virginia School of Medicine, Charlottesville; Silverback Therapeutics, Inc, Seattle, WA (C.A.C.); and Department of Neuroscience, Merck & Co, Inc, West point, PA (V.P.S.)
| | - David McHedlishvili
- From the Departments of Pharmacology (J.Y., D.M., W.E.M., N.A.G., D.A.B., P.Q.B.) and Psychology (A.E.), University of Virginia School of Medicine, Charlottesville; Silverback Therapeutics, Inc, Seattle, WA (C.A.C.); and Department of Neuroscience, Merck & Co, Inc, West point, PA (V.P.S.)
| | - William E McIntire
- From the Departments of Pharmacology (J.Y., D.M., W.E.M., N.A.G., D.A.B., P.Q.B.) and Psychology (A.E.), University of Virginia School of Medicine, Charlottesville; Silverback Therapeutics, Inc, Seattle, WA (C.A.C.); and Department of Neuroscience, Merck & Co, Inc, West point, PA (V.P.S.)
| | - Nick A Guagliardo
- From the Departments of Pharmacology (J.Y., D.M., W.E.M., N.A.G., D.A.B., P.Q.B.) and Psychology (A.E.), University of Virginia School of Medicine, Charlottesville; Silverback Therapeutics, Inc, Seattle, WA (C.A.C.); and Department of Neuroscience, Merck & Co, Inc, West point, PA (V.P.S.)
| | - Alev Erisir
- From the Departments of Pharmacology (J.Y., D.M., W.E.M., N.A.G., D.A.B., P.Q.B.) and Psychology (A.E.), University of Virginia School of Medicine, Charlottesville; Silverback Therapeutics, Inc, Seattle, WA (C.A.C.); and Department of Neuroscience, Merck & Co, Inc, West point, PA (V.P.S.)
| | - Craig A Coburn
- From the Departments of Pharmacology (J.Y., D.M., W.E.M., N.A.G., D.A.B., P.Q.B.) and Psychology (A.E.), University of Virginia School of Medicine, Charlottesville; Silverback Therapeutics, Inc, Seattle, WA (C.A.C.); and Department of Neuroscience, Merck & Co, Inc, West point, PA (V.P.S.)
| | - Vincent P Santarelli
- From the Departments of Pharmacology (J.Y., D.M., W.E.M., N.A.G., D.A.B., P.Q.B.) and Psychology (A.E.), University of Virginia School of Medicine, Charlottesville; Silverback Therapeutics, Inc, Seattle, WA (C.A.C.); and Department of Neuroscience, Merck & Co, Inc, West point, PA (V.P.S.)
| | - Douglas A Bayliss
- From the Departments of Pharmacology (J.Y., D.M., W.E.M., N.A.G., D.A.B., P.Q.B.) and Psychology (A.E.), University of Virginia School of Medicine, Charlottesville; Silverback Therapeutics, Inc, Seattle, WA (C.A.C.); and Department of Neuroscience, Merck & Co, Inc, West point, PA (V.P.S.)
| | - Paula Q Barrett
- From the Departments of Pharmacology (J.Y., D.M., W.E.M., N.A.G., D.A.B., P.Q.B.) and Psychology (A.E.), University of Virginia School of Medicine, Charlottesville; Silverback Therapeutics, Inc, Seattle, WA (C.A.C.); and Department of Neuroscience, Merck & Co, Inc, West point, PA (V.P.S.).
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27
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Weaver JL, Arandjelovic S, Brown G, K Mendu S, S Schappe M, Buckley MW, Chiu YH, Shu S, Kim JK, Chung J, Krupa J, Jevtovic-Todorovic V, Desai BN, Ravichandran KS, Bayliss DA. Hematopoietic pannexin 1 function is critical for neuropathic pain. Sci Rep 2017; 7:42550. [PMID: 28195232 PMCID: PMC5307344 DOI: 10.1038/srep42550] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 01/12/2017] [Indexed: 12/13/2022] Open
Abstract
Neuropathic pain symptoms respond poorly to available therapeutics, with most treated patients reporting unrelieved pain and significant impairment in daily life. Here, we show that Pannexin 1 (Panx1) in hematopoietic cells is required for pain-like responses following nerve injury in mice, and a potential therapeutic target. Panx1 knockout mice (Panx1-/-) were protected from hypersensitivity in two sciatic nerve injury models. Bone marrow transplantation studies show that expression of functional Panx1 in hematopoietic cells is necessary for mechanical hypersensitivity following nerve injury. Reconstitution of irradiated Panx1 knockout mice with hematopoietic Panx1-/- cells engineered to re-express Panx1 was sufficient to recover hypersensitivity after nerve injury; this rescue required expression of a Panx1 variant that can be activated by G protein-coupled receptors (GPCRs). Finally, chemically distinct Panx1 inhibitors blocked development of nerve injury-induced hypersensitivity and partially relieved this hypersensitivity after it was established. These studies indicate that Panx1 expressed in immune cells is critical for pain-like effects following nerve injury in mice, perhaps via a GPCR-mediated activation mechanism, and suggest that inhibition of Panx1 may be useful in treating neuropathic pain.
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Affiliation(s)
- Janelle L Weaver
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Sanja Arandjelovic
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Gregory Brown
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Suresh K Mendu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Michael S Schappe
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Monica W Buckley
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Shaofang Shu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Jin K Kim
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Joyce Chung
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Julia Krupa
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | | | - Bimal N Desai
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
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28
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Manichaikul A, Rich SS, Allison MA, Guagliardo NA, Bayliss DA, Carey RM, Barrett PQ. KCNK3 Variants Are Associated With Hyperaldosteronism and Hypertension. Hypertension 2016; 68:356-64. [PMID: 27296998 DOI: 10.1161/hypertensionaha.116.07564] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/11/2016] [Indexed: 12/19/2022]
Abstract
Blood pressure (BP) is a complex trait that is the consequence of an interaction between genetic and environmental determinants. Previous studies have demonstrated increased BP in mice with global deletion of TASK-1 channels contemporaneous with diverse dysregulation of aldosterone production. In humans, genome-wide association studies in ≈100 000 individuals of European, East Asian, and South Asian ancestry identified a single nucleotide polymorphism (SNP) in KCNK3 (the gene encoding TASK-1) associated with mean arterial pressure. The current study was motivated by the hypotheses that (1) association of KCNK3 SNPs with BP and related traits extends to blacks and Hispanics, and (2) KCNK3 SNPs exhibit associations with plasma renin activity and aldosterone levels. We examined baseline BP measurements for 7840 participants from the Multi-Ethnic Study of Atherosclerosis (MESA), and aldosterone levels and plasma renin activity in a subset of 1653 MESA participants. We identified statistically significant association of the previously reported KCNK3 SNP (rs1275988) with mean arterial pressure in MESA blacks (P=0.024) and a nearby SNP (rs13394970) in MESA Hispanics (P=0.031). We discovered additional KCNK3 SNP associations with systolic BP, mean arterial pressure, and hypertension. We also identified statistically significant association of KCNK3 rs2586886 with plasma aldosterone level in MESA and demonstrated that global deletion of TASK-1 channels in mice produces a mild-hyperaldosteronism, not associated with a decrease in renin. Our results suggest that genetic variation in the KCNK3 gene may contribute to BP variation and less severe hypertensive disorders in which aldosterone may be one of several causative factors.
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Affiliation(s)
- Ani Manichaikul
- From the Center for Public Health Genomics (A.M., S.S.R.), Biostatistics Section, Department of Public Health Sciences (A.M.), Department of Pharmacology (N.A.G., D.A.B., P.Q.B.), and Division of Endocrinology and Metabolism and Department of Medicine (R.M.C.), University of Virginia, Charlottesville; and Department of Family and Preventive Medicine, University of California San Diego, La Jolla (M.A.A.)
| | - Stephen S Rich
- From the Center for Public Health Genomics (A.M., S.S.R.), Biostatistics Section, Department of Public Health Sciences (A.M.), Department of Pharmacology (N.A.G., D.A.B., P.Q.B.), and Division of Endocrinology and Metabolism and Department of Medicine (R.M.C.), University of Virginia, Charlottesville; and Department of Family and Preventive Medicine, University of California San Diego, La Jolla (M.A.A.)
| | - Matthew A Allison
- From the Center for Public Health Genomics (A.M., S.S.R.), Biostatistics Section, Department of Public Health Sciences (A.M.), Department of Pharmacology (N.A.G., D.A.B., P.Q.B.), and Division of Endocrinology and Metabolism and Department of Medicine (R.M.C.), University of Virginia, Charlottesville; and Department of Family and Preventive Medicine, University of California San Diego, La Jolla (M.A.A.)
| | - Nick A Guagliardo
- From the Center for Public Health Genomics (A.M., S.S.R.), Biostatistics Section, Department of Public Health Sciences (A.M.), Department of Pharmacology (N.A.G., D.A.B., P.Q.B.), and Division of Endocrinology and Metabolism and Department of Medicine (R.M.C.), University of Virginia, Charlottesville; and Department of Family and Preventive Medicine, University of California San Diego, La Jolla (M.A.A.)
| | - Douglas A Bayliss
- From the Center for Public Health Genomics (A.M., S.S.R.), Biostatistics Section, Department of Public Health Sciences (A.M.), Department of Pharmacology (N.A.G., D.A.B., P.Q.B.), and Division of Endocrinology and Metabolism and Department of Medicine (R.M.C.), University of Virginia, Charlottesville; and Department of Family and Preventive Medicine, University of California San Diego, La Jolla (M.A.A.)
| | - Robert M Carey
- From the Center for Public Health Genomics (A.M., S.S.R.), Biostatistics Section, Department of Public Health Sciences (A.M.), Department of Pharmacology (N.A.G., D.A.B., P.Q.B.), and Division of Endocrinology and Metabolism and Department of Medicine (R.M.C.), University of Virginia, Charlottesville; and Department of Family and Preventive Medicine, University of California San Diego, La Jolla (M.A.A.)
| | - Paula Q Barrett
- From the Center for Public Health Genomics (A.M., S.S.R.), Biostatistics Section, Department of Public Health Sciences (A.M.), Department of Pharmacology (N.A.G., D.A.B., P.Q.B.), and Division of Endocrinology and Metabolism and Department of Medicine (R.M.C.), University of Virginia, Charlottesville; and Department of Family and Preventive Medicine, University of California San Diego, La Jolla (M.A.A.).
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29
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Guyenet PG, Bayliss DA, Stornetta RL, Ludwig MG, Kumar NN, Shi Y, Burke PGR, Kanbar R, Basting TM, Holloway BB, Wenker IC. Proton detection and breathing regulation by the retrotrapezoid nucleus. J Physiol 2016; 594:1529-51. [PMID: 26748771 PMCID: PMC4799966 DOI: 10.1113/jp271480] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 01/04/2016] [Indexed: 01/26/2023] Open
Abstract
We discuss recent evidence which suggests that the principal central respiratory chemoreceptors are located within the retrotrapezoid nucleus (RTN) and that RTN neurons are directly sensitive to [H(+) ]. RTN neurons are glutamatergic. In vitro, their activation by [H(+) ] requires expression of a proton-activated G protein-coupled receptor (GPR4) and a proton-modulated potassium channel (TASK-2) whose transcripts are undetectable in astrocytes and the rest of the lower brainstem respiratory network. The pH response of RTN neurons is modulated by surrounding astrocytes but genetic deletion of RTN neurons or deletion of both GPR4 and TASK-2 virtually eliminates the central respiratory chemoreflex. Thus, although this reflex is regulated by innumerable brain pathways, it seems to operate predominantly by modulating the discharge rate of RTN neurons, and the activation of RTN neurons by hypercapnia may ultimately derive from their intrinsic pH sensitivity. RTN neurons increase lung ventilation by stimulating multiple aspects of breathing simultaneously. They stimulate breathing about equally during quiet wake and non-rapid eye movement (REM) sleep, and to a lesser degree during REM sleep. The activity of RTN neurons is regulated by inhibitory feedback and by excitatory inputs, notably from the carotid bodies. The latter input operates during normo- or hypercapnia but fails to activate RTN neurons under hypocapnic conditions. RTN inhibition probably limits the degree of hyperventilation produced by hypocapnic hypoxia. RTN neurons are also activated by inputs from serotonergic neurons and hypothalamic neurons. The absence of RTN neurons probably underlies the sleep apnoea and lack of chemoreflex that characterize congenital central hypoventilation syndrome.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | | | - Natasha N Kumar
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Peter G R Burke
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Roy Kanbar
- Department of Pharmaceutical Sciences, Lebanese American University, Beyrouth, Lebanon
| | - Tyler M Basting
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Benjamin B Holloway
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
| | - Ian C Wenker
- Department of Pharmacology, University of Virginia, Charlottesville, VA, 22908, USA
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30
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Zhou C, Liang P, Liu J, Ke B, Wang X, Li F, Li T, Bayliss DA, Chen X. HCN1 Channels Contribute to the Effects of Amnesia and Hypnosis but not Immobility of Volatile Anesthetics. Anesth Analg 2015; 121:661-666. [PMID: 26287296 DOI: 10.1213/ane.0000000000000830] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Hyperpolarization-activated, cyclic nucleotide-gated (HCN) subtype 1 (HCN1) channels have been identified as targets of ketamine to produce hypnosis. Volatile anesthetics also inhibit HCN1 channels. However, the effects of HCN1 channels on volatile anesthetics in vivo are still elusive. This study uses global and conditional HCN1 knockout mice to evaluate how HCN1 channels affect the actions of volatile anesthetics. METHODS Minimum alveolar concentrations (MACs) of isoflurane and sevoflurane that induced immobility (MAC of immobility) and/or hypnosis (MAC of hypnosis) were determined in wild-type mice, global HCN1 knockout (HCN1) mice, HCN1 channel gene with 2 lox-P sites flanking a region of the fourth exon of HCN1 (HCN1) mice, and forebrain-selective HCN1 knockout (HCN1: cre) mice. Immobility of mice was defined as no purposeful reactions to tail-clamping stimulus, and hypnosis was defined as loss of righting reflex. The amnestic effects of isoflurane and sevoflurane were evaluated by fear-potentiated startle in these 4 strains of mice. RESULTS All MAC values were expressed as mean ± SEM. For MAC of immobility of isoflurane, no significant difference was found among wild-type, HCN1, HCN1, and HCN1: cre mice (all ~1.24%-1.29% isoflurane). For both HCN1 and HCN1: cre mice, the MAC of hypnosis for isoflurane (each ~1.05% isoflurane) was significantly increased over their nonknockout controls: HCN1 versus wild-type (0.86% ± 0.03%, P < 0.001) and HCN1: cre versus HCN1 mice (0.84% ± 0.03%, P < 0.001); no significant difference was found between HCN1 and HCN1: cre mice. For MAC of immobility of sevoflurane, no significant difference was found among wild-type, HCN1, HCN1, and HCN1: cre mice (all ~2.6%-2.7% sevoflurane). For both HCN1 and HCN1: cre mice, the MAC of hypnosis for sevoflurane (each ~1.90% sevoflurane) was significantly increased over their nonknockout controls: HCN1 versus wild-type (1.58% ± 0.05%, P < 0.001) and HCN1: cre versus HCN1 mice (1.56% ± 0.05%, P < 0.001). No significant difference was found between HCN1 and HCN1: cre mice. By fear-potentiated startle experiments, amnestic effects of isoflurane and sevoflurane were significantly attenuated in HCN1 and HCN1: cre mice (both P < 0.002 versus wild-type or HCN1 mice). No significant difference was found between HCN1 and HCN1: cre mice. CONCLUSIONS Forebrain HCN1 channels contribute to hypnotic and amnestic effects of volatile anesthetics, but HCN1 channels are not involved in the immobilizing actions of volatile anesthetics.
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Affiliation(s)
- Cheng Zhou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, P.R. China
| | - Peng Liang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, Sichuan, P.R. China
| | - Jin Liu
- Department of Anesthesiology and Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, P.R. China
| | - Bowen Ke
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, P.R. China
| | - Xiaojia Wang
- Department of Anesthesiology and Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, P.R. China
| | - Fengshan Li
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, P.R. China
| | - Tao Li
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, P.R. China
| | - Douglas A Bayliss
- Department of Pharmacology and Anesthesiology, University of Virginia, Charlottesville, Virginia
| | - Xiangdong Chen
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, West China Hospital of Sichuan University, Chengdu, Sichuan, P.R. China; Department of Anesthesiology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China
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31
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Abstract
Recent advances have clarified how the brain detects CO2 to regulate breathing (central respiratory chemoreception). These mechanisms are reviewed and their significance is presented in the general context of CO2/pH homeostasis through breathing. At rest, respiratory chemoreflexes initiated at peripheral and central sites mediate rapid stabilization of arterial PCO2 and pH. Specific brainstem neurons (e.g., retrotrapezoid nucleus, RTN; serotonergic) are activated by PCO2 and stimulate breathing. RTN neurons detect CO2 via intrinsic proton receptors (TASK-2, GPR4), synaptic input from peripheral chemoreceptors and signals from astrocytes. Respiratory chemoreflexes are arousal state dependent whereas chemoreceptor stimulation produces arousal. When abnormal, these interactions lead to sleep-disordered breathing. During exercise, central command and reflexes from exercising muscles produce the breathing stimulation required to maintain arterial PCO2 and pH despite elevated metabolic activity. The neural circuits underlying central command and muscle afferent control of breathing remain elusive and represent a fertile area for future investigation.
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Affiliation(s)
- Patrice G Guyenet
- Department of Pharmacology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, VA 22908-0735, USA.
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, VA 22908-0735, USA
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32
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Guagliardo NA, Le TH, Bayliss DA, Breault DT, Barrett PQ. Abstract MP09: Adrenal-specific Deletion of TASK Channels Evokes Normal-Renin Hypertension. Hypertension 2015. [DOI: 10.1161/hyp.66.suppl_1.mp09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objectives:
Dysregulation of aldosterone (Aldo) production is predicted to evoke major features of idiopathic primary hyperaldosteronism (IHA): low renin, elevated blood pressure and suppressed control by high Na. We have previously demonstrated in mice that global deletion of background TWIK-related acid-sensitive K (TASK) channels (TASK-1, TASK-3) effect a ~20mV decrease in the membrane potential of Zona Glomerulosa (ZG) cells to produce frank autonomous overproduction of Aldo, low renin, and hypertension (HT), mimicking the salient features of human IHA. In the current study, we ask if specific deletion of TASK channels in ZG cells is sufficient to produce hyperaldosteronism and the predicted sequela or if extra-adrenal deletion of TASK channels is required.
Design and Methods:
We generated a trigenic mouse-line (
AS
+Cre
::TASK-1
ff
::TASK-3
ff
, zT1T3KO) in which TASK-1 and TASK-3 subunits were specifically deleted in ZG cells. The renin-angiotensin-aldosterone system (RAAS) was evaluated in mice housed in metabolic cages and stabilized on various salt diets. Urinary Aldo concentration was measured and normalized to creatinine (ng Aldo/mg creatinine; 24 hr. urine collection). Blood pressure was recorded in conscious, freely moving mice using radio telemetry, and plasma renin concentration was measured from tail vein sampling.
Results:
Overproduction of aldosterone on normal-salt diet (0.3% Na) was modest in zT1T3KO mice compared to littermate controls (WT; WT 9.4; KO 11.8 ng/mg, 1.25-fold). Suppression of Aldo production by high-salt (2% Na) was blunted, exaggerating the difference in Aldo production between genotypes (WT 3.0; KO 7.4 ng/mg, 2.43-fold). zT1T3KO mice were hypertensive (mean MAP: WT 103.5; KO 113.1 mmHg), yet renin levels remained normal. Neither hyperaldosteronism nor HT could be corrected by angiotensin II receptor blockade, suggesting overproduction of Aldo and HT are independent of RAAS.
Conclusions:
Limiting TASK deletion to ZG cells results in normal renin HT driven by modest autonomous hyperaldosteronism, a stark contrast to the phenotypic features of IHA recapitulated by global TASK deletion. Together these mouse models provide insight into the role of ZG- vs extra-adrenal-dysfunction in the pathology of IHA.
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Affiliation(s)
| | - Thu H Le
- Univ of Virginia, Charlottesville, VA
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33
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Kumar NN, Velic A, Soliz J, Shi Y, Li K, Wang S, Weaver JL, Sen J, Abbott SBG, Lazarenko RM, Ludwig MG, Perez-Reyes E, Mohebbi N, Bettoni C, Gassmann M, Suply T, Seuwen K, Guyenet PG, Wagner CA, Bayliss DA. PHYSIOLOGY. Regulation of breathing by CO₂ requires the proton-activated receptor GPR4 in retrotrapezoid nucleus neurons. Science 2015; 348:1255-60. [PMID: 26068853 DOI: 10.1126/science.aaa0922] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 05/06/2015] [Indexed: 12/12/2022]
Abstract
Blood gas and tissue pH regulation depend on the ability of the brain to sense CO2 and/or H(+) and alter breathing appropriately, a homeostatic process called central respiratory chemosensitivity. We show that selective expression of the proton-activated receptor GPR4 in chemosensory neurons of the mouse retrotrapezoid nucleus (RTN) is required for CO2-stimulated breathing. Genetic deletion of GPR4 disrupted acidosis-dependent activation of RTN neurons, increased apnea frequency, and blunted ventilatory responses to CO2. Reintroduction of GPR4 into RTN neurons restored CO2-dependent RTN neuronal activation and rescued the ventilatory phenotype. Additional elimination of TASK-2 (K(2P)5), a pH-sensitive K(+) channel expressed in RTN neurons, essentially abolished the ventilatory response to CO2. The data identify GPR4 and TASK-2 as distinct, parallel, and essential central mediators of respiratory chemosensitivity.
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Affiliation(s)
- Natasha N Kumar
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Ana Velic
- Institute of Physiology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Jorge Soliz
- Institute of Veterinary Physiology, University of Zurich, Zurich, CH-8057, Switzerland. Centre de Recherche du CHU de Québec, Département de Pédiatrie, Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - Yingtang Shi
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Keyong Li
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Sheng Wang
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA. Department of Physiology, Hebei Medical University, Shijiazhuang, Hebei, 050017, China
| | - Janelle L Weaver
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Josh Sen
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Stephen B G Abbott
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA. School of Medical Sciences, University of New South Wales, New South Wales 2052, Australia. Department of Neurology, Harvard Medical School and Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Roman M Lazarenko
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | | | - Edward Perez-Reyes
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Nilufar Mohebbi
- Institute of Physiology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Max Gassmann
- Institute of Veterinary Physiology, University of Zurich, Zurich, CH-8057, Switzerland
| | - Thomas Suply
- Novartis Institutes for Biomedical Research, Basel, CH-4002, Switzerland
| | - Klaus Seuwen
- Novartis Institutes for Biomedical Research, Basel, CH-4002, Switzerland
| | - Patrice G Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, CH-8057, Switzerland.
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA.
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34
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Billaud M, Chiu YH, Lohman AW, Parpaite T, Butcher JT, Mutchler SM, DeLalio LJ, Artamonov MV, Sandilos JK, Best AK, Somlyo AV, Thompson RJ, Le TH, Ravichandran KS, Bayliss DA, Isakson BE. A molecular signature in the pannexin1 intracellular loop confers channel activation by the α1 adrenoreceptor in smooth muscle cells. Sci Signal 2015; 8:ra17. [PMID: 25690012 DOI: 10.1126/scisignal.2005824] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Both purinergic signaling through nucleotides such as ATP (adenosine 5'-triphosphate) and noradrenergic signaling through molecules such as norepinephrine regulate vascular tone and blood pressure. Pannexin1 (Panx1), which forms large-pore, ATP-releasing channels, is present in vascular smooth muscle cells in peripheral blood vessels and participates in noradrenergic responses. Using pharmacological approaches and mice conditionally lacking Panx1 in smooth muscle cells, we found that Panx1 contributed to vasoconstriction mediated by the α1 adrenoreceptor (α1AR), whereas vasoconstriction in response to serotonin or endothelin-1 was independent of Panx1. Analysis of the Panx1-deficient mice showed that Panx1 contributed to blood pressure regulation especially during the night cycle when sympathetic nervous activity is highest. Using mimetic peptides and site-directed mutagenesis, we identified a specific amino acid sequence in the Panx1 intracellular loop that is essential for activation by α1AR signaling. Collectively, these data describe a specific link between noradrenergic and purinergic signaling in blood pressure homeostasis.
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Affiliation(s)
- Marie Billaud
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Alexander W Lohman
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Thibaud Parpaite
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Joshua T Butcher
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Stephanie M Mutchler
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Leon J DeLalio
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Mykhaylo V Artamonov
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Joanna K Sandilos
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Angela K Best
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Avril V Somlyo
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Roger J Thompson
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Thu H Le
- Department of Medicine, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Kodi S Ravichandran
- Center for Cell Clearance, University of Virginia, Charlottesville, VA 22908, USA. Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA. Beirne B. Carter Center for Immunology Research, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA. Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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Zhang H, Dong H, Cilz NI, Kurada L, Hu B, Wada E, Bayliss DA, Porter JE, Lei S. Neurotensinergic Excitation of Dentate Gyrus Granule Cells via Gαq-Coupled Inhibition of TASK-3 Channels. Cereb Cortex 2014; 26:977-90. [PMID: 25405940 DOI: 10.1093/cercor/bhu267] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Neurotensin (NT) is a 13-amino acid peptide and serves as a neuromodulator in the brain. Whereas NT has been implicated in learning and memory, the underlying cellular and molecular mechanisms are ill-defined. Because the dentate gyrus receives profound innervation of fibers containing NT and expresses high density of NT receptors, we examined the effects of NT on the excitability of dentate gyrus granule cells (GCs). Our results showed that NT concentration dependently increased action potential (AP) firing frequency of the GCs by the activation of NTS1 receptors resulting in the depolarization of the GCs. NT-induced enhancement of AP firing frequency was not caused indirectly by releasing glutamate, GABA, acetylcholine, or dopamine, but due to the inhibition of TASK-3 K(+) channels. NT-mediated excitation of the GCs was G protein dependent, but independent of phospholipase C, intracellular Ca(2+) release, and protein kinase C. Immunoprecipitation experiment demonstrates that the activation of NTS1 receptors induced the association of Gαq/11 and TASK-3 channels suggesting a direct coupling of Gαq/11 to TASK-3 channels. Endogenously released NT facilitated the excitability of the GCs contributing to the induction of long-term potentiation at the perforant path-GC synapses. Our results provide a cellular mechanism that helps to explain the roles of NT in learning and memory.
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Affiliation(s)
- Haopeng Zhang
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, People's Republic of China
| | - Hailong Dong
- Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, People's Republic of China
| | - Nicholas I Cilz
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Lalitha Kurada
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Binqi Hu
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Etsuko Wada
- Department of Degenerative Neurological Diseases, National Institute of Neuroscience, Tokyo, Japan
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - James E Porter
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
| | - Saobo Lei
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA
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Bayliss DA, Barhanin J, Gestreau C, Guyenet PG. The role of pH-sensitive TASK channels in central respiratory chemoreception. Pflugers Arch 2014; 467:917-29. [PMID: 25346157 DOI: 10.1007/s00424-014-1633-9] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 10/08/2014] [Accepted: 10/12/2014] [Indexed: 01/16/2023]
Abstract
A number of the subunits within the family of K2P background K(+) channels are sensitive to changes in extracellular pH in the physiological range, making them likely candidates to mediate various pH-dependent processes. Based on expression patterns within several brainstem neuronal cell groups that are believed to function in CO2/H(+) regulation of breathing, three TASK subunits-TASK-1, TASK-2, and TASK-3-were specifically hypothesized to contribute to this central respiratory chemoreflex. For the acid-sensitive TASK-1 and TASK-3 channels, despite widespread expression at multiple levels within the brainstem respiratory control system (including presumptive chemoreceptor populations), experiments in knockout mice provided no evidence for their involvement in CO2 regulation of breathing. By contrast, the alkaline-activated TASK-2 channel has a more restricted brainstem distribution and was localized to the Phox2b-expressing chemoreceptor neurons of the retrotrapezoid nucleus (RTN). Remarkably, in a Phox2b(27Ala/+) mouse genetic model of congenital central hypoventilation syndrome (CCHS) that is characterized by reduced central respiratory chemosensitivity, selective ablation of Phox2b-expressing RTN neurons was accompanied by a corresponding loss of TASK-2 expression. Furthermore, genetic deletion of TASK-2 blunted RTN neuronal pH sensitivity in vitro, reduced alkaline-induced respiratory network inhibition in situ and diminished the ventilatory response to CO2/H(+) in vivo. Notably, a subpopulation of RTN neurons from TASK-2(-/-) mice retained their pH sensitivity, at least in part due to a residual pH-sensitive background K(+) current, suggesting that other mechanisms (and perhaps other K2P channels) for RTN neuronal pH sensitivity are yet to be identified.
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Affiliation(s)
- Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA, 22908-0735, USA,
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Morenilla-Palao C, Luis E, Fernández-Peña C, Quintero E, Weaver JL, Bayliss DA, Viana F. Ion channel profile of TRPM8 cold receptors reveals a role of TASK-3 potassium channels in thermosensation. Cell Rep 2014; 8:1571-82. [PMID: 25199828 DOI: 10.1016/j.celrep.2014.08.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 06/09/2014] [Accepted: 08/01/2014] [Indexed: 10/24/2022] Open
Abstract
Animals sense cold ambient temperatures through the activation of peripheral thermoreceptors that express TRPM8, a cold- and menthol-activated ion channel. These receptors can discriminate a very wide range of temperatures from innocuous to noxious. The molecular mechanism responsible for the variable sensitivity of individual cold receptors to temperature is unclear. To address this question, we performed a detailed ion channel expression analysis of cold-sensitive neurons, combining bacterial artificial chromosome (BAC) transgenesis with a molecular-profiling approach in fluorescence-activated cell sorting (FACS)-purified TRPM8 neurons. We found that TASK-3 leak potassium channels are highly enriched in a subpopulation of these sensory neurons. The thermal threshold of TRPM8 cold neurons is decreased during TASK-3 blockade and in mice lacking TASK-3, and, most importantly, these mice display hypersensitivity to cold. Our results demonstrate a role of TASK-3 channels in thermosensation, showing that a channel-based combinatorial strategy in TRPM8 cold thermoreceptors leads to molecular specialization and functional diversity.
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Affiliation(s)
- Cruz Morenilla-Palao
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain.
| | - Enoch Luis
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain
| | - Carlos Fernández-Peña
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain
| | - Eva Quintero
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain
| | - Janelle L Weaver
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Félix Viana
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, 03550 San Juan de Alicante, Spain.
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Abstract
Pannexin 1 (Panx1) channels are generally represented as non-selective, large-pore channels that release ATP. Emerging roles have been described for Panx1 in mediating purinergic signaling in the normal nervous, cardiovascular, and immune systems, where they may be activated by mechanical stress, ionotropic and metabotropic receptor signaling, and via proteolytic cleavage of the Panx1 C-terminus. Panx1 channels are widely expressed in various cell types, and it is now thought that targeting these channels therapeutically may be beneficial in a number of pathophysiological contexts, such as asthma, atherosclerosis, hypertension, and ischemic-induced seizures. Even as interest in Panx1 channels is burgeoning, some of their basic properties, mechanisms of modulation, and proposed functions remain controversial, with recent reports challenging some long-held views regarding Panx1 channels. In this brief review, we summarize some well-established features of Panx1 channels; we then address some current confounding issues surrounding Panx1 channels, especially with respect to intrinsic channel properties, in order to raise awareness of these unsettled issues for future research.
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Affiliation(s)
- Yu-Hsin Chiu
- Department of Pharmacology; University of Virginia; Charlottesville, VA USA
| | - Kodi S Ravichandran
- Beirne B. Carter Center for Immunology Research; University of Virginia; Charlottesville, VA USA; Center for Cell Clearance; University of Virginia; Charlottesville, VA USA; Department of Microbiology; Immunology and Cancer Research; University of Virginia; Charlottesville, VA USA
| | - Douglas A Bayliss
- Department of Pharmacology; University of Virginia; Charlottesville, VA USA
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Kazmierczak M, Zhang X, Chen B, Mulkey DK, Shi Y, Wagner PG, Pivaroff-Ward K, Sassic JK, Bayliss DA, Jegla T. External pH modulates EAG superfamily K+ channels through EAG-specific acidic residues in the voltage sensor. ACTA ACUST UNITED AC 2013; 141:721-35. [PMID: 23712551 PMCID: PMC3664700 DOI: 10.1085/jgp.201210938] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The Ether-a-go-go (EAG) superfamily of voltage-gated K+ channels consists of three functionally distinct gene families (Eag, Elk, and Erg) encoding a diverse set of low-threshold K+ currents that regulate excitability in neurons and muscle. Previous studies indicate that external acidification inhibits activation of three EAG superfamily K+ channels, Kv10.1 (Eag1), Kv11.1 (Erg1), and Kv12.1 (Elk1). We show here that Kv10.2, Kv12.2, and Kv12.3 are similarly inhibited by external protons, suggesting that high sensitivity to physiological pH changes is a general property of EAG superfamily channels. External acidification depolarizes the conductance–voltage (GV) curves of these channels, reducing low threshold activation. We explored the mechanism of this high pH sensitivity in Kv12.1, Kv10.2, and Kv11.1. We first examined the role of acidic voltage sensor residues that mediate divalent cation block of voltage activation in EAG superfamily channels because protons reduce the sensitivity of Kv12.1 to Zn2+. Low pH similarly reduces Mg2+ sensitivity of Kv10.1, and we found that the pH sensitivity of Kv11.1 was greatly attenuated at 1 mM Ca2+. Individual neutralizations of a pair of EAG-specific acidic residues that have previously been implicated in divalent block of diverse EAG superfamily channels greatly reduced the pH response in Kv12.1, Kv10.2, and Kv11.1. Our results therefore suggest a common mechanism for pH-sensitive voltage activation in EAG superfamily channels. The EAG-specific acidic residues may form the proton-binding site or alternatively are required to hold the voltage sensor in a pH-sensitive conformation. The high pH sensitivity of EAG superfamily channels suggests that they could contribute to pH-sensitive K+ currents observed in vivo.
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Affiliation(s)
- Marcin Kazmierczak
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
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Kenwood BM, Weaver JL, Bajwa A, Poon IK, Byrne FL, Murrow BA, Calderone JA, Huang L, Divakaruni AS, Tomsig JL, Okabe K, Lo RH, Cameron Coleman G, Columbus L, Yan Z, Saucerman JJ, Smith JS, Holmes JW, Lynch KR, Ravichandran KS, Uchiyama S, Santos WL, Rogers GW, Okusa MD, Bayliss DA, Hoehn KL. Identification of a novel mitochondrial uncoupler that does not depolarize the plasma membrane. Mol Metab 2013; 3:114-23. [PMID: 24634817 DOI: 10.1016/j.molmet.2013.11.005] [Citation(s) in RCA: 152] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 11/15/2013] [Accepted: 11/15/2013] [Indexed: 11/29/2022] Open
Abstract
Dysregulation of oxidative phosphorylation is associated with increased mitochondrial reactive oxygen species production and some of the most prevalent human diseases including obesity, cancer, diabetes, neurodegeneration, and heart disease. Chemical 'mitochondrial uncouplers' are lipophilic weak acids that transport protons into the mitochondrial matrix via a pathway that is independent of ATP synthase, thereby uncoupling nutrient oxidation from ATP production. Mitochondrial uncouplers also lessen the proton motive force across the mitochondrial inner membrane and thereby increase the rate of mitochondrial respiration while decreasing production of reactive oxygen species. Thus, mitochondrial uncouplers are valuable chemical tools that enable the measurement of maximal mitochondrial respiration and they have been used therapeutically to decrease mitochondrial reactive oxygen species production. However, the most widely used protonophore uncouplers such as carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) and 2,4-dinitrophenol have off-target activity at other membranes that lead to a range of undesired effects including plasma membrane depolarization, mitochondrial inhibition, and cytotoxicity. These unwanted properties interfere with the measurement of mitochondrial function and result in a narrow therapeutic index that limits their usefulness in the clinic. To identify new mitochondrial uncouplers that lack off-target activity at the plasma membrane we screened a small molecule chemical library. Herein we report the identification and validation of a novel mitochondrial protonophore uncoupler (2-fluorophenyl){6-[(2-fluorophenyl)amino](1,2,5-oxadiazolo[3,4-e]pyrazin-5-yl)}amine, named BAM15, that does not depolarize the plasma membrane. Compared to FCCP, an uncoupler of equal potency, BAM15 treatment of cultured cells stimulates a higher maximum rate of mitochondrial respiration and is less cytotoxic. Furthermore, BAM15 is bioactive in vivo and dose-dependently protects mice from acute renal ischemic-reperfusion injury. From a technical standpoint, BAM15 represents an effective new tool that allows the study of mitochondrial function in the absence of off-target effects that can confound data interpretation. From a therapeutic perspective, BAM15-mediated protection from ischemia-reperfusion injury and its reduced toxicity will hopefully reignite interest in pharmacological uncoupling for the treatment of the myriad of diseases that are associated with altered mitochondrial function.
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Key Words
- ANT, adenine nucleotide translocase
- Bioenergetics
- CCCP
- DNP
- ECAR, extracellular acidification rate
- FCCP
- FCCP, carbonyl cyanide p-trifluoromethoxyphenylhydrazone
- Ischemia
- Mitochondria
- OCR, oxygen consumption rate
- ROS, reactive oxygen species
- TCA cycle, tricarboxylic acid cycle
- TMPD, N,N,N′,N′-tetramethyl-p-phenylenediamine dihydrochloride
- TMRM, tetramethylrhodamine
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Affiliation(s)
- Brandon M Kenwood
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Janelle L Weaver
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Amandeep Bajwa
- Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Ivan K Poon
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Frances L Byrne
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Beverley A Murrow
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Joseph A Calderone
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061, USA
| | - Liping Huang
- Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Ajit S Divakaruni
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
| | - Jose L Tomsig
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | | | - Ryan H Lo
- Department of Chemistry, University of Virginia, Charlottesville, VA 22908, USA
| | - G Cameron Coleman
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Linda Columbus
- Department of Chemistry, University of Virginia, Charlottesville, VA 22908, USA
| | - Zhen Yan
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA ; Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA ; Department of Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Jeffrey J Saucerman
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA ; Department of Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Jeffrey S Smith
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Jeffrey W Holmes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA ; Department of Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA
| | - Kevin R Lynch
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
| | | | - Webster L Santos
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061, USA
| | | | - Mark D Okusa
- Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
| | - Kyle L Hoehn
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA ; Department of Medicine, University of Virginia, Charlottesville, VA 22908, USA ; Department of Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA ; Emily Couric Clinical Cancer Center, University of Virginia, Charlottesville, VA 22908, USA
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Bonin RP, Zurek AA, Yu J, Bayliss DA, Orser BA. Hyperpolarization-activated current (In) is reduced in hippocampal neurons from Gabra5-/- mice. PLoS One 2013; 8:e58679. [PMID: 23516534 PMCID: PMC3597723 DOI: 10.1371/journal.pone.0058679] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 02/05/2013] [Indexed: 01/06/2023] Open
Abstract
Changes in the expression of γ-aminobutyric acid type A (GABAA) receptors can either drive or mediate homeostatic alterations in neuronal excitability. A homeostatic relationship between α5 subunit-containing GABAA (α5GABAA) receptors that generate a tonic inhibitory conductance, and HCN channels that generate a hyperpolarization-activated cation current (Ih) was recently described for cortical neurons, where a reduction in Ih was accompanied by a reciprocal increase in the expression of α5GABAA receptors resulting in the preservation of dendritosomatic synaptic function. Here, we report that in mice that lack the α5 subunit gene (Gabra5−/−), cultured embryonic hippocampal pyramidal neurons and ex vivo CA1 hippocampal neurons unexpectedly exhibited a decrease in Ih current density (by 40% and 28%, respectively), compared with neurons from wild-type (WT) mice. The resting membrane potential and membrane hyperpolarization induced by blockade of Ih with ZD-7288 were similar in cultured WT and Gabra5−/− neurons. In contrast, membrane hyperpolarization measured after a train of action potentials was lower in Gabra5−/− neurons than in WT neurons. Also, membrane impedance measured in response to low frequency stimulation was greater in cultured Gabra5−/− neurons. Finally, the expression of HCN1 protein that generates Ih was reduced by 41% in the hippocampus of Gabra5−/− mice. These data indicate that loss of a tonic GABAergic inhibitory conductance was followed by a compensatory reduction in Ih. The results further suggest that the maintenance of resting membrane potential is preferentially maintained in mature and immature hippocampal neurons through the homeostatic co-regulation of structurally and biophysically distinct cation and anion channels.
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Affiliation(s)
- Robert P. Bonin
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Agnieszka A. Zurek
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Jieying Yu
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Douglas A. Bayliss
- Department of Pharmacology, University of Virginia Health System, Charlottesville, Virginia, United States of America
| | - Beverley A. Orser
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada
- Department of Anesthesia, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
- * E-mail:
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Abstract
It is widely recognized that ATP, along with other nucleotides, subserves important intercellular signalling processes. Among various nucleotide release mechanisms, the relatively recently identified pannexin 1 (Panx1) channel is gaining prominence by virtue of its ability to support nucleotide permeation and release in a variety of different tissues. Here, we review recent advances in our understanding of the factors that control Panx1 channel activity. By using electrophysiological and biochemical approaches, diverse mechanisms that dynamically regulate Panx1 channel function have been identified in various settings; these include, among others, activation by caspase-mediated channel cleavage in apoptotic immune cells, by G protein-coupled receptors in vascular smooth muscle, by low oxygen tension in erythrocytes and neurons, by high extracellular K(+) in various cell types and by stretch/strain in airway epithelia. Delineating the distinct mechanisms of Panx1 modulation that prevail in different physiological contexts provides the possibility that these channels, and ATP release, could ultimately be targeted in a context-dependent manner.
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Affiliation(s)
- Joanna K Sandilos
- Department of Pharmacology, University of Virginia, Charlottesville, VA, USA.
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Lohman AW, Weaver JL, Billaud M, Sandilos JK, Griffiths R, Straub AC, Penuela S, Leitinger N, Laird DW, Bayliss DA, Isakson BE. S-nitrosylation inhibits pannexin 1 channel function. J Biol Chem 2012; 287:39602-12. [PMID: 23033481 DOI: 10.1074/jbc.m112.397976] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
S-nitrosylation is a post-translational modification on cysteine(s) that can regulate protein function, and pannexin 1 (Panx1) channels are present in the vasculature, a tissue rich in nitric oxide (NO) species. Therefore, we investigated whether Panx1 can be S-nitrosylated and whether this modification can affect channel activity. Using the biotin switch assay, we found that application of the NO donor S-nitrosoglutathione (GSNO) or diethylammonium (Z)-1-1(N,N-diethylamino)diazen-1-ium-1,2-diolate (DEA NONOate) to human embryonic kidney (HEK) 293T cells expressing wild type (WT) Panx1 and mouse aortic endothelial cells induced Panx1 S-nitrosylation. Functionally, GSNO and DEA NONOate attenuated Panx1 currents; consistent with a role for S-nitrosylation, current inhibition was reversed by the reducing agent dithiothreitol and unaffected by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a blocker of guanylate cyclase activity. In addition, ATP release was significantly inhibited by treatment with both NO donors. To identify which cysteine residue(s) was S-nitrosylated, we made single cysteine-to-alanine substitutions in Panx1 (Panx1(C40A), Panx1(C346A), and Panx1(C426A)). Mutation of these single cysteines did not prevent Panx1 S-nitrosylation; however, mutation of either Cys-40 or Cys-346 prevented Panx1 current inhibition and ATP release by GSNO. This observation suggested that multiple cysteines may be S-nitrosylated to regulate Panx1 channel function. Indeed, we found that mutation of both Cys-40 and Cys-346 (Panx1(C40A/C346A)) prevented Panx1 S-nitrosylation by GSNO as well as the GSNO-mediated inhibition of Panx1 current and ATP release. Taken together, these results indicate that S-nitrosylation of Panx1 at Cys-40 and Cys-346 inhibits Panx1 channel currents and ATP release.
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Affiliation(s)
- Alexander W Lohman
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, Virginia 22908, USA
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Guagliardo NA, Yao J, Hu C, Schertz EM, Tyson DA, Carey RM, Bayliss DA, Barrett PQ. TASK-3 channel deletion in mice recapitulates low-renin essential hypertension. Hypertension 2012; 59:999-1005. [PMID: 22493079 DOI: 10.1161/hypertensionaha.111.189662] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Idiopathic primary hyperaldosteronism (IHA) and low-renin essential hypertension (LREH) are common forms of hypertension, characterized by an elevated aldosterone-renin ratio and hypersensitivity to angiotensin II. They are suggested to be 2 states within a disease spectrum that progresses from LREH to IHA as the control of aldosterone production by the renin-angiotensin system is weakened. The mechanism(s) that drives this progression remains unknown. Deletion of Twik-related acid-sensitive K(+) channels (TASK) subunits, TASK-1 and TASK-3, in mice (T1T3KO) produces a model of human IHA. Here, we determine the effect of deleting only TASK-3 (T3KO) on the control of aldosterone production and blood pressure. We find that T3KO mice recapitulate key characteristics of human LREH, salt-sensitive hypertension, mild overproduction of aldosterone, decreased plasma-renin concentration with elevated aldosterone:renin ratio, hypersensitivity to endogenous and exogenous angiotensin II, and failure to suppress aldosterone production with dietary sodium loading. The relative differences in levels of aldosterone output and aldosterone:renin ratio and in autonomy of aldosterone production between T1T3KO and T3KO mice are reminiscent of differences in human hypertensive patients with LREH and IHA. Our studies establish a model of LREH and suggest that loss of TASK channel activity may be one mechanism that advances the syndrome of low renin hypertension.
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Affiliation(s)
- Nick A Guagliardo
- Department of Pharmacology, University of Virginia, School of Medicine, Charlottesville, VA 22908, USA
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Sandilos JK, Chiu YH, Chekeni FB, Armstrong AJ, Walk SF, Ravichandran KS, Bayliss DA. C terminal block of the Pannexin 1 channel pore and its relief by proteolytic cleavage. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.1048.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Yu-Hsin Chiu
- PharmacologyUniversity of VirginiaCharlottesvilleVA
| | | | | | - Scott F Walk
- MicrobiologyUniversity of VirginiaCharlottesvilleVA
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Sandilos JK, Chiu YH, Chekeni FB, Armstrong AJ, Walk SF, Ravichandran KS, Bayliss DA. Pannexin 1, an ATP release channel, is activated by caspase cleavage of its pore-associated C-terminal autoinhibitory region. J Biol Chem 2012; 287:11303-11. [PMID: 22311983 DOI: 10.1074/jbc.m111.323378] [Citation(s) in RCA: 224] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pannexin 1 (PANX1) channels mediate release of ATP, a "find-me" signal that recruits macrophages to apoptotic cells; PANX1 activation during apoptosis requires caspase-mediated cleavage of PANX1 at its C terminus, but how the C terminus inhibits basal channel activity is not understood. Here, we provide evidence suggesting that the C terminus interacts with the human PANX1 (hPANX1) pore and that cleavage-mediated channel activation requires disruption of this inhibitory interaction. Basally silent hPANX1 channels localized on the cell membrane could be activated directly by protease-mediated C-terminal cleavage, without additional apoptotic effectors. By serial deletion, we identified a C-terminal region just distal to the caspase cleavage site that is required for inhibition of hPANX1; point mutations within this small region resulted in partial activation of full-length hPANX1. Consistent with the C-terminal tail functioning as a pore blocker, we found that truncated and constitutively active hPANX1 channels could be inhibited, in trans, by the isolated hPANX1 C terminus either in cells or when applied directly as a purified peptide in inside-out patch recordings. Furthermore, using a cysteine cross-linking approach, we showed that relief of inhibition following cleavage requires dissociation of the C terminus from the channel pore. Collectively, these data suggest a mechanism of hPANX1 channel regulation whereby the intact, pore-associated C terminus inhibits the full-length hPANX1 channel and a remarkably well placed caspase cleavage site allows effective removal of key inhibitory C-terminal determinants to activate hPANX1.
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Affiliation(s)
- Joanna K Sandilos
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
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Gotter AL, Santarelli VP, Doran SM, Tannenbaum PL, Kraus RL, Rosahl TW, Meziane H, Montial M, Reiss DR, Wessner K, McCampbell A, Stevens J, Brunner JI, Fox SV, Uebele VN, Bayliss DA, Winrow CJ, Renger JJ. TASK-3 as a potential antidepressant target. Brain Res 2011; 1416:69-79. [PMID: 21885038 DOI: 10.1016/j.brainres.2011.08.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 08/09/2011] [Indexed: 10/17/2022]
Abstract
Modulation of TASK-3 (Kcnk9) potassium channels affect neurotransmitter release in thalamocortical centers and other sleep-related nuclei having the capacity to regulate arousal cycles and REM sleep changes associated with mood disorders and antidepressant action. Circumstantial evidence from this and previous studies suggest the potential for TASK-3 to be a novel antidepressant therapeutic target; TASK-3 knock-out mice display augmented circadian amplitude and exhibit sleep architecture characterized by suppressed REM activity. Detailed analysis of locomotor activity indicates that the amplitudes of activity bout duration and bout number are augmented in TASK-3 mutants well beyond that seen in wildtypes, findings substantiated by amplitude increases in body temperature and EEG recordings of sleep stage bouts. Polysomnographic analysis of TASK-3 mutants reveals increases in nocturnal active wake and suppressed REM sleep time while increased slow wave sleep typifies the inactive phase, findings that have implications for the cognitive impact of reduced TASK-3 activity. In direct measures of their resistance to despair behavior, TASK-3 knock-outs displayed significant decreases in immobility relative to wildtype controls in both tail suspension and forced swim tests. Treatment of wildtype animals with the antidepressant Fluoxetine markedly reduced REM sleep, while leaving active wake and slow wave sleep relatively intact. Remarkably, these effects were absent in TASK-3 mutants indicating that TASK-3 is either directly involved in the mechanism of this drug's action, or participates in parallel pathways that achieve the same effect. Together, these results support the TASK-3 channel to act as a therapeutic target for antidepressant action.
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Affiliation(s)
- Anthony L Gotter
- Department of Neuroscience, Merck Research Laboratories, West Point, PA, USA.
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Guagliardo NA, Yao J, Bayliss DA, Barrett PQ. TASK channels are not required to mount an aldosterone secretory response to metabolic acidosis in mice. Mol Cell Endocrinol 2011; 336:47-52. [PMID: 21111026 PMCID: PMC3057342 DOI: 10.1016/j.mce.2010.11.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2010] [Revised: 11/15/2010] [Accepted: 11/15/2010] [Indexed: 12/31/2022]
Abstract
The stimulation of aldosterone production by acidosis enhances proton excretion and serves to limit disturbances in systemic acid-base equilibrium. Yet, the mechanisms by which protons stimulate aldosterone production from cells of the adrenal cortex remain largely unknown. TWIK-related acid sensitive K channels (TASK) are inhibited by extracellular protons within the physiological range and have emerged as important regulators of aldosterone production in the adrenal cortex. Here we show that congenic C57BL/6J mice with genetic deletion of TASK-1 (K(2P)3.1) and TASK-3 (K(2P)9.1) channel subunits overproduce aldosterone and display an enhanced sensitivity to steroidogenic stimuli, including a more pronounced steroidogenic response to chronic NH(4)Cl loading. Thus, we conclude that TASK channels are not required for the stimulation of aldosterone production by protons but their inhibition by physiological acidosis may contribute to full expression of the steroidogenic response.
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Affiliation(s)
- Nick A. Guagliardo
- University of Virginia, Department of Pharmacology, 1340 Jefferson Park Ave. Charlottesville, VA 22908, USA
| | - Junlan Yao
- University of Virginia, Department of Pharmacology, 1340 Jefferson Park Ave. Charlottesville, VA 22908, USA
| | - Douglas A. Bayliss
- University of Virginia, Department of Pharmacology, 1340 Jefferson Park Ave. Charlottesville, VA 22908, USA
| | - Paula Q. Barrett
- University of Virginia, Department of Pharmacology, 1340 Jefferson Park Ave. Charlottesville, VA 22908, USA
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Abstract
Systemic administration of local anesthetics has beneficial perioperative properties and an anesthetic-sparing and antiarrhythmic effect, although the detailed mechanisms of these actions remain unclear. In the present study, we investigated the effects of a local anesthetic, lidocaine, on hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels that contribute to the pacemaker currents in rhythmically oscillating cells of the heart and brain. Voltage-clamp recordings were used to examine the properties of cloned HCN subunit currents expressed in Xenopus laevis oocytes and human embryonic kidney (HEK) 293 cells under control condition and lidocaine administration. Lidocaine inhibited HCN1, HCN2, HCN1-HCN2, and HCN4 channel currents at 100 μM in both oocytes and/or HEK 293 cells; it caused a decrease in both tonic and maximal current (∼30-50% inhibition) and slowed current activation kinetics for all subunits. In addition, lidocaine evoked a hyperpolarizing shift in half-activation voltage (ΔV(1/2) of ∼-10 to -14 mV), but only for HCN1 and HCN1-HCN2 channels. By fitting concentration-response data to logistic functions, we estimated half-maximal (EC(50)) concentrations of lidocaine of ∼30 to 40 μM for the shift in V(1/2) observed with HCN1 and HCN1-HCN2; for inhibition of current amplitude, calculated EC(50) values were ∼50 to 70 μM for HCN1, HCN2, and HCN1-HCN2 channels. A lidocaine metabolite, monoethylglycinexylidide (100 μM), had similar inhibitory actions on HCN channels. These results indicate that lidocaine potently inhibits HCN channel subunits in dose-dependent manner over a concentration range relevant for systemic application. The ability of local anesthetics to modulate I(h) in central neurons may contribute to central nervous system depression, whereas effects on I(f) in cardiac pacemaker cells may contribute to the antiarrhythmic and/or cardiovascular toxic action.
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Affiliation(s)
- Qing-Tao Meng
- Laboratory of Anesthesia and Critical Care Medicine, West China Hospital of Sichuan University, Chengdu, China
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Sandilos JK, Chekeni FB, Elliott MR, Walk SF, Kinchen JM, Lazarowski ER, Armstrong AJ, Penuela S, Laird DW, Salvesen GS, Isakson BE, Ravichandran KS, Bayliss DA. Caspases Mediate Pannexin 1 Channel Activation in Apoptotic Cells. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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