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Davis H, Paterson DJ, Herring N. Post-Ganglionic Sympathetic Neurons can Directly Sense Raised Extracellular Na + via SCN7a/Na x. Front Physiol 2022; 13:931094. [PMID: 35784866 PMCID: PMC9247455 DOI: 10.3389/fphys.2022.931094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
The relationship between dietary NaCl intake and high blood pressure is well-established, and occurs primarily through activation of the sympathetic nervous system. Nax, a Na+-sensitive Na+ channel, plays a pivotal role in driving sympathetic excitability, which is thought to originate from central regions controlling neural outflow. We investigated whether post-ganglionic sympathetic neurons from different ganglia innervating cardiac and vasculature tissue can also directly sense extracellular Na+. Using whole-cell patch clamp recordings we demonstrate that sympathetic neurons from three sympathetic ganglia (superior cervical, stellate and superior mesenteric/coeliac) respond to elevated extracellular NaCl concentration. In sympathetic stellate ganglia neurons, we established that the effect of NaCl was dose-dependent and independent of osmolarity, Cl- and membrane Ca2+ flux, and critically dependent on extracellular Na+ concentration. We show that Nax is expressed in sympathetic stellate ganglia neurons at a transcript and protein level using single-cell RNA-sequencing and immunohistochemistry respectively. Additionally, the response to NaCl was prevented by siRNA-mediated knockdown of Nax, but not by inhibition of other membrane Na+ pathways. Together, these results demonstrate that post-ganglionic sympathetic neurons are direct sensors of extracellular Na+ via Nax, which could contribute to sympathetic driven hypertension.
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Affiliation(s)
- Harvey Davis
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
- Wellcome Trust OXION Initiative in Ion Channels and Disease, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - David J Paterson
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
- Wellcome Trust OXION Initiative in Ion Channels and Disease, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Neil Herring
- Burdon Sanderson Cardiac Science Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
- Oxford Heart Centre, Oxford University Hospitals NHS Foundation Trust, John Radcliffe Hospital, Oxford, United Kingdom
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Dolivo D, Rodrigues A, Sun L, Li Y, Hou C, Galiano R, Hong SJ, Mustoe T. The Na x (SCN7A) channel: an atypical regulator of tissue homeostasis and disease. Cell Mol Life Sci 2021; 78:5469-5488. [PMID: 34100980 PMCID: PMC11072345 DOI: 10.1007/s00018-021-03854-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/15/2021] [Accepted: 05/08/2021] [Indexed: 12/15/2022]
Abstract
Within an articulately characterized family of ion channels, the voltage-gated sodium channels, exists a black sheep, SCN7A (Nax). Nax, in contrast to members of its molecular family, has lost its voltage-gated character and instead rapidly evolved a new function as a concentration-dependent sensor of extracellular sodium ions and subsequent signal transducer. As it deviates fundamentally in function from the rest of its family, and since the bulk of the impressive body of literature elucidating the pathology and biochemistry of voltage-gated sodium channels has been performed in nervous tissue, reports of Nax expression and function have been sparse. Here, we investigate available reports surrounding expression and potential roles for Nax activity outside of nervous tissue. With these studies as justification, we propose that Nax likely acts as an early sensor that detects loss of tissue homeostasis through the pathological accumulation of extracellular sodium and/or through endothelin signaling. Sensation of homeostatic aberration via Nax then proceeds to induce pathological tissue phenotypes via promotion of pro-inflammatory and pro-fibrotic responses, induced through direct regulation of gene expression or through the generation of secondary signaling molecules, such as lactate, that can operate in an autocrine or paracrine fashion. We hope that our synthesis of much of the literature investigating this understudied protein will inspire more research into Nax not simply as a biochemical oddity, but also as a potential pathophysiological regulator and therapeutic target.
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Affiliation(s)
- David Dolivo
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
| | - Adrian Rodrigues
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
| | - Lauren Sun
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
| | - Yingxing Li
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
| | - Chun Hou
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
- Department of Plastic and Cosmetic Surgery, First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Robert Galiano
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA
| | - Seok Jong Hong
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA.
- , 300 E. Superior St., Chicago, IL, 60611, USA.
| | - Thomas Mustoe
- Department of Surgery, Northwestern University-Feinberg School of Medicine, Chicago, USA.
- , 737 N. Michigan Ave., Chicago, IL, 60611, USA.
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Elevated serum levels of endothelin-1 in patients with chronic inflammatory demyelinating polyneuropathy. Clin Chim Acta 2018; 476:49-53. [DOI: 10.1016/j.cca.2017.11.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 11/11/2017] [Indexed: 12/18/2022]
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Tu NH, Katano T, Matsumura S, Funatsu N, Pham VM, Fujisawa JI, Ito S. Na + /K + -ATPase coupled to endothelin receptor type B stimulates peripheral nerve regeneration via lactate signalling. Eur J Neurosci 2017; 46:2096-2107. [PMID: 28700113 DOI: 10.1111/ejn.13647] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/07/2017] [Accepted: 07/07/2017] [Indexed: 12/22/2022]
Abstract
We have recently demonstrated that endothelin (ET) is functionally coupled to Nax , a Na+ concentration-sensitive Na+ channel for lactate release via ET receptor type B (ETB R) and is involved in peripheral nerve regeneration in a sciatic nerve transection-regeneration mouse model. Nax is known to interact directly with Na+ /K+ -ATPase, leading to lactate production in the brain. To investigate the role of Na+ /K+ -ATPase in peripheral nerve regeneration, in this study, we applied ouabain, a Na+ /K+ -ATPase inhibitor, to the cut site for 4 weeks with an osmotic pump. While functional recovery and nerve reinnervation to the toe started at 5 weeks after axotomy and were completed by 7 weeks, ouabain delayed them by 2 weeks. The delay by ouabain was improved by lactate, and its effect was blocked by α-cyano-4-hydroxy-cinnamic acid (CIN), a broad monocarboxylate transporter (MCT) inhibitor. In primary cultures of dorsal root ganglia, neurite outgrowth of neurons and lactate release into the culture medium was inhibited by ouabain. Conversely, lactate enhanced the neurite outgrowth, which was blocked by CIN, but not by AR-C155858, a MCT1/2-selective inhibitor. ET-1 and ET-3 increased neurite outgrowth of neurons, which was attenuated by an ETB R antagonist, ouabain and 2 protein kinase C inhibitors. Taken together with the finding that ETB R was expressed in Schwann cells, these results demonstrate that ET enhanced neurite outgrowth of neurons mediated by Na+ /K+ -ATPase via ETB R in Schwann cells. This study suggests that Na+ /K+ -ATPase coupled to the ET-ETB R system plays a critical role in peripheral nerve regeneration via lactate signalling.
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Affiliation(s)
- Nguyen H Tu
- Department of Medical Chemistry, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, 573-1010, Japan
| | - Tayo Katano
- Department of Medical Chemistry, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, 573-1010, Japan
| | - Shinji Matsumura
- Department of Medical Chemistry, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, 573-1010, Japan
| | - Nobuo Funatsu
- Department of Medical Chemistry, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, 573-1010, Japan
| | - Vuong Minh Pham
- Department of Medical Chemistry, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, 573-1010, Japan
| | - Jun-Ichi Fujisawa
- Department of Microbiology, Kansai Medical University, Hirakata, Japan
| | - Seiji Ito
- Department of Medical Chemistry, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, 573-1010, Japan
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Tu NH, Katano T, Matsumura S, Pham VM, Muratani T, Minami T, Ito S. Role of c-Jun N-terminal kinase in late nerve regeneration monitored byin vivoimaging of thy1-yellow fluorescent protein transgenic mice. Eur J Neurosci 2016; 43:548-60. [DOI: 10.1111/ejn.13139] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/05/2015] [Accepted: 11/19/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Nguyen H. Tu
- Department of Medical Chemistry; Kansai Medical University; 2-5-1 Shin-machi Hirakata 573-1010 Japan
| | - Tayo Katano
- Department of Medical Chemistry; Kansai Medical University; 2-5-1 Shin-machi Hirakata 573-1010 Japan
| | - Shinji Matsumura
- Department of Medical Chemistry; Kansai Medical University; 2-5-1 Shin-machi Hirakata 573-1010 Japan
| | - Vuong Minh Pham
- Department of Medical Chemistry; Kansai Medical University; 2-5-1 Shin-machi Hirakata 573-1010 Japan
| | | | - Toshiaki Minami
- Department of Anesthesiology; Osaka Medical College; Takatsuki Japan
| | - Seiji Ito
- Department of Medical Chemistry; Kansai Medical University; 2-5-1 Shin-machi Hirakata 573-1010 Japan
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Matsumoto M, Hiyama TY, Kuboyama K, Suzuki R, Fujikawa A, Noda M. Channel properties of Nax expressed in neurons. PLoS One 2015; 10:e0126109. [PMID: 25961826 PMCID: PMC4427406 DOI: 10.1371/journal.pone.0126109] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 03/19/2015] [Indexed: 12/19/2022] Open
Abstract
Nax is a sodium-concentration ([Na+])-sensitive Na channel with a gating threshold of ~150 mM for extracellular [Na+] ([Na+]o) in vitro. We previously reported that Nax was preferentially expressed in the glial cells of sensory circumventricular organs including the subfornical organ, and was involved in [Na+] sensing for the control of salt-intake behavior. Although Nax was also suggested to be expressed in the neurons of some brain regions including the amygdala and cerebral cortex, the channel properties of Nax have not yet been adequately characterized in neurons. We herein verified that Nax was expressed in neurons in the lateral amygdala of mice using an antibody that was newly generated against mouse Nax. To investigate the channel properties of Nax expressed in neurons, we established an inducible cell line of Nax using the mouse neuroblastoma cell line, Neuro-2a, which is endogenously devoid of the expression of Nax. Functional analyses of this cell line revealed that the [Na+]-sensitivity of Nax in neuronal cells was similar to that expressed in glial cells. The cation selectivity sequence of the Nax channel in cations was revealed to be Na+ ≈ Li+ > Rb+ > Cs+ for the first time. Furthermore, we demonstrated that Nax bound to postsynaptic density protein 95 (PSD95) through its PSD95/Disc-large/ZO-1 (PDZ)-binding motif at the C-terminus in neurons. The interaction between Nax and PSD95 may be involved in promoting the surface expression of Nax channels because the depletion of endogenous PSD95 resulted in a decrease in Nax at the plasma membrane. These results indicated, for the first time, that Nax functions as a [Na+]-sensitive Na channel in neurons as well as in glial cells.
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Affiliation(s)
- Masahito Matsumoto
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Japan
| | - Takeshi Y. Hiyama
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Japan
- School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Kazuya Kuboyama
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Japan
| | - Ryoko Suzuki
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Japan
| | - Akihiro Fujikawa
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Japan
| | - Masaharu Noda
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Japan
- School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
- * E-mail:
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Huu Tu N, Katano T, Matsumura S, Ito S. Involvement of endothelin B receptor in peripheral nerve regeneration using sciatic nerve transection-regeneration model. ACTA ACUST UNITED AC 2015. [DOI: 10.11154/pain.30.167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Nguyen Huu Tu
- Department of Medical Chemistry, Kansai Medical University
| | - Tayo Katano
- Department of Medical Chemistry, Kansai Medical University
| | | | - Seiji Ito
- Department of Medical Chemistry, Kansai Medical University
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Abstract
Na x, which is preferentially expressed in the glial cells of sensory circumventricular organs in the brain, is a sodium channel that is poorly homologous to voltage-gated sodium channels. We previously reported that Na x is a sodium concentration ([Na+])-sensitive, but not a voltage-sensitive channel that is critically involved in body-fluid homeostasis. Nax-knockout mice do not stop ingesting salt even when dehydrated and transiently develop hypernatremia. [Na+] in body fluids is strictly controlled at 135 to 145 mM in mammals. Although the set point must be within this range, Na x was shown to have a threshold value of ~150 mM for extracellular [Na+] ([Na+]o) for activation in vitro. Therefore, the [Na+]o dependency of Na x in vivo is presumably modified by an as yet unidentified mechanism. We recently demonstrated that the [Na+]o dependency of Na x in the subfornical organ was adjusted to the physiological range by endothelin-3. Pharmacological experiments revealed that endothelin receptor B signaling was involved in this modulation of Na x gating through protein kinase C and ERK1/2 activation. In addition, we identified a case of essential hypernatremia caused by autoimmunity to Na x. Occurrence of a ganglioneuroma composed of Schwann-like cells that robustly expressed Na x was likely to induce the autoimmune response in this patient. An intravenous injection of the immunoglobulin fraction of the patient’s serum, which contained anti-Na x antibodies, into mice reproduced the patient’s symptoms. This review provides an overview of the physiological functions of Na x by summarizing our recent studies.
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Affiliation(s)
- Masaharu Noda
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Japan
- School of Life Science, The Graduate University for Advanced Studies, Okazaki, Japan
| | - Takeshi Y. Hiyama
- Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Japan
- School of Life Science, The Graduate University for Advanced Studies, Okazaki, Japan
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