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O’Brien F, Feetham CH, Staunton CA, Hext K, Barrett-Jolley R. Temperature modulates PVN pre-sympathetic neurones via transient receptor potential ion channels. Front Pharmacol 2023; 14:1256924. [PMID: 37920211 PMCID: PMC10618372 DOI: 10.3389/fphar.2023.1256924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/03/2023] [Indexed: 11/04/2023] Open
Abstract
The paraventricular nucleus (PVN) of the hypothalamus plays a vital role in maintaining homeostasis and modulates cardiovascular function via autonomic pre-sympathetic neurones. We have previously shown that coupling between transient receptor potential cation channel subfamily V Member 4 (Trpv4) and small-conductance calcium-activated potassium channels (SK) in the PVN facilitate osmosensing, but since TRP channels are also thermosensitive, in this report we investigated the temperature sensitivity of these neurones. Methods: TRP channel mRNA was quantified from mouse PVN with RT-PCR and thermosensitivity of Trpv4-like PVN neuronal ion channels characterised with cell-attached patch-clamp electrophysiology. Following recovery of temperature-sensitive single-channel kinetic schema, we constructed a predictive stochastic mathematical model of these neurones and validated this with electrophysiological recordings of action current frequency. Results: 7 thermosensitive TRP channel genes were found in PVN punches. Trpv4 was the most abundant of these and was identified at the single channel level on PVN neurones. We investigated the thermosensitivity of these Trpv4-like channels; open probability (Po) markedly decreased when temperature was decreased, mediated by a decrease in mean open dwell times. Our neuronal model predicted that PVN spontaneous action current frequency (ACf) would increase as temperature is decreased and in our electrophysiological experiments, we found that ACf from PVN neurones was significantly higher at lower temperatures. The broad-spectrum channel blocker gadolinium (100 µM), was used to block the warm-activated, Ca2+-permeable Trpv4 channels. In the presence of gadolinium (100 µM), the temperature effect was largely retained. Using econazole (10 µM), a blocker of Trpm2, we found there were significant increases in overall ACf and the temperature effect was inhibited. Conclusion: Trpv4, the abundantly transcribed thermosensitive TRP channel gene in the PVN appears to contribute to intrinsic thermosensitive properties of PVN neurones. At physiological temperatures (37°C), we observed relatively low ACf primarily due to the activity of Trpm2 channels, whereas at room temperature, where most of the previous characterisation of PVN neuronal activity has been performed, ACf is much higher, and appears to be predominately due to reduced Trpv4 activity. This work gives insight into the fundamental mechanisms by which the body decodes temperature signals and maintains homeostasis.
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Affiliation(s)
| | | | | | | | - Richard Barrett-Jolley
- Department of Musculoskeletal Ageing Science, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
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Jin X, Xie J, Yeh CW, Chen JC, Cheng CJ, Lien CC, Huang CL. WNK1 promotes water homeostasis by acting as a central osmolality sensor for arginine vasopressin release. J Clin Invest 2023; 133:e164222. [PMID: 37071482 PMCID: PMC10231991 DOI: 10.1172/jci164222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 04/14/2023] [Indexed: 04/19/2023] Open
Abstract
Maintaining internal osmolality constancy is essential for life. Release of arginine vasopressin (AVP) in response to hyperosmolality is critical. Current hypotheses for osmolality sensors in circumventricular organs (CVOs) of the brain focus on mechanosensitive membrane proteins. The present study demonstrated that intracellular protein kinase WNK1 was involved. Focusing on vascular-organ-of-lamina-terminalis (OVLT) nuclei, we showed that WNK1 kinase was activated by water restriction. Neuron-specific conditional KO (cKO) of Wnk1 caused polyuria with decreased urine osmolality that persisted in water restriction and blunted water restriction-induced AVP release. Wnk1 cKO also blunted mannitol-induced AVP release but had no effect on osmotic thirst response. The role of WNK1 in the osmosensory neurons in CVOs was supported by neuronal pathway tracing. Hyperosmolality-induced increases in action potential firing in OVLT neurons was blunted by Wnk1 deletion or pharmacological WNK inhibitors. Knockdown of Kv3.1 channel in OVLT by shRNA reproduced the phenotypes. Thus, WNK1 in osmosensory neurons in CVOs detects extracellular hypertonicity and mediates the increase in AVP release by activating Kv3.1 and increasing action potential firing from osmosensory neurons.
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Affiliation(s)
- Xin Jin
- Department of Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Jian Xie
- Department of Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | | | - Jen-Chi Chen
- Department of Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Chih-Jen Cheng
- Department of Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Cheng-Chang Lien
- Institute of Neuroscience and
- Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chou-Long Huang
- Department of Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
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3
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Zeng ML, Kong S, Chen TX, Peng BW. Transient Receptor Potential Vanilloid 4: a Double-Edged Sword in the Central Nervous System. Mol Neurobiol 2023; 60:1232-1249. [PMID: 36434370 DOI: 10.1007/s12035-022-03141-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 11/17/2022] [Indexed: 11/26/2022]
Abstract
Transient receptor potential vanilloid 4 (TRPV4) is a nonselective cation channel that can be activated by diverse stimuli, such as heat, mechanical force, hypo-osmolarity, and arachidonic acid metabolites. TRPV4 is widely expressed in the central nervous system (CNS) and participates in many significant physiological processes. However, accumulative evidence has suggested that deficiency, abnormal expression or distribution, and overactivation of TRPV4 are involved in pathological processes of multiple neurological diseases. Here, we review the latest studies concerning the known features of this channel, including its expression, structure, and its physiological and pathological roles in the CNS, proposing an emerging therapeutic strategy for CNS diseases.
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Affiliation(s)
- Meng-Liu Zeng
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China.,Medical Science Research Center, Zhongnan Hospital of Wuhan University, Wuhan, 430071, China
| | - Shuo Kong
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China
| | - Tao-Xiang Chen
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China
| | - Bi-Wen Peng
- Department of Physiology, Hubei Provincial Key Laboratory of Developmentally Originated Disease, Taikang Medical School (School of Basic Medical Sciences), Wuhan University, Donghu Rd185#, Wuhan, 430071, Hubei, China.
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Baumer-Harrison C, Breza JM, Sumners C, Krause EG, de Kloet AD. Sodium Intake and Disease: Another Relationship to Consider. Nutrients 2023; 15:535. [PMID: 36771242 PMCID: PMC9921152 DOI: 10.3390/nu15030535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/14/2023] [Accepted: 01/15/2023] [Indexed: 01/22/2023] Open
Abstract
Sodium (Na+) is crucial for numerous homeostatic processes in the body and, consequentially, its levels are tightly regulated by multiple organ systems. Sodium is acquired from the diet, commonly in the form of NaCl (table salt), and substances that contain sodium taste salty and are innately palatable at concentrations that are advantageous to physiological homeostasis. The importance of sodium homeostasis is reflected by sodium appetite, an "all-hands-on-deck" response involving the brain, multiple peripheral organ systems, and endocrine factors, to increase sodium intake and replenish sodium levels in times of depletion. Visceral sensory information and endocrine signals are integrated by the brain to regulate sodium intake. Dysregulation of the systems involved can lead to sodium overconsumption, which numerous studies have considered causal for the development of diseases, such as hypertension. The purpose here is to consider the inverse-how disease impacts sodium intake, with a focus on stress-related and cardiometabolic diseases. Our proposition is that such diseases contribute to an increase in sodium intake, potentially eliciting a vicious cycle toward disease exacerbation. First, we describe the mechanism(s) that regulate each of these processes independently. Then, we highlight the points of overlap and integration of these processes. We propose that the analogous neural circuitry involved in regulating sodium intake and blood pressure, at least in part, underlies the reciprocal relationship between neural control of these functions. Finally, we conclude with a discussion on how stress-related and cardiometabolic diseases influence these circuitries to alter the consumption of sodium.
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Affiliation(s)
- Caitlin Baumer-Harrison
- Department of Physiology and Aging, College of Medicine, University of Florida, Gainesville, FL 32603, USA
- Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL 32610, USA
- Center for Smell and Taste, University of Florida, Gainesville, FL 32610, USA
- Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Joseph M. Breza
- Department of Psychology, College of Arts and Sciences, Eastern Michigan University, Ypsilanti, MI 48197, USA
| | - Colin Sumners
- Department of Physiology and Aging, College of Medicine, University of Florida, Gainesville, FL 32603, USA
- Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL 32610, USA
- Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
| | - Eric G. Krause
- Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL 32610, USA
- Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
| | - Annette D. de Kloet
- Department of Physiology and Aging, College of Medicine, University of Florida, Gainesville, FL 32603, USA
- Center for Integrative Cardiovascular and Metabolic Disease, University of Florida, Gainesville, FL 32610, USA
- Center for Smell and Taste, University of Florida, Gainesville, FL 32610, USA
- Evelyn F. and William L. McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
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Sheng W, Harden SW, Tan Y, Krause EG, Frazier CJ. Dendritic osmosensors modulate activity-induced calcium influx in oxytocinergic magnocellular neurons of the mouse PVN. eLife 2021; 10:e63486. [PMID: 34250900 PMCID: PMC8457833 DOI: 10.7554/elife.63486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 07/11/2021] [Indexed: 11/13/2022] Open
Abstract
Hypothalamic oxytocinergic magnocellular neurons have a fascinating ability to release peptide from both their axon terminals and from their dendrites. Existing data indicates that the relationship between somatic activity and dendritic release is not constant, but the mechanisms through which this relationship can be modulated are not completely understood. Here, we use a combination of electrical and optical recording techniques to quantify activity-induced calcium influx in proximal vs. distal dendrites of oxytocinergic magnocellular neurons located in the paraventricular nucleus of the hypothalamus (OT-MCNs). Results reveal that the dendrites of OT-MCNs are weak conductors of somatic voltage changes; however, activity-induced dendritic calcium influx can be robustly regulated by both osmosensitive and non-osmosensitive ion channels located along the dendritic membrane. Overall, this study reveals that dendritic conductivity is a dynamic and endogenously regulated feature of OT-MCNs that is likely to have substantial functional impact on central oxytocin release.
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Affiliation(s)
- Wanhui Sheng
- Department of Pharmacodynamics, College of Pharmacy, University of FloridaGainesvilleUnited States
| | - Scott W Harden
- Department of Pharmacodynamics, College of Pharmacy, University of FloridaGainesvilleUnited States
| | - Yalun Tan
- Department of Pharmacodynamics, College of Pharmacy, University of FloridaGainesvilleUnited States
- Department of Anesthesiology, School of Medicine, Stanford UniversityStanfordUnited States
| | - Eric G Krause
- Department of Pharmacodynamics, College of Pharmacy, University of FloridaGainesvilleUnited States
- Center for Integrative Cardiovascular and Metabolic Diseases, University of FloridaGainesvilleUnited States
- Evelyn F. and William L. McKnight Brain Institute, University of FloridaGainesvilleUnited States
| | - Charles J Frazier
- Department of Pharmacodynamics, College of Pharmacy, University of FloridaGainesvilleUnited States
- Center for Integrative Cardiovascular and Metabolic Diseases, University of FloridaGainesvilleUnited States
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Bewick GS, Banks RW. Mechanotransduction channels in proprioceptive sensory nerve terminals: still an open question? CURRENT OPINION IN PHYSIOLOGY 2021. [DOI: 10.1016/j.cophys.2020.11.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Liu ST, Chou MY, Wu LC, Horng JL, Lin LY. Transient receptor potential vanilloid 4 modulates ion balance through the isotocin pathway in zebrafish (Danio rerio). Am J Physiol Regul Integr Comp Physiol 2020; 318:R751-R759. [DOI: 10.1152/ajpregu.00307.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isotocin controls ion regulation through modulating the functions of ionocytes (also called mitochondria-rich cells or chloride cells). However, little is known about the upstream molecule of the isotocin system. Herein, we identify transient receptor potential vanilloid 4 (TRPV4), which regulates the mRNA and protein expressions of isotocin and affects ion regulation through the isotocin pathway. Double immunohistochemical results showed that TRPV4 is expressed in isotocinergic neurons in the hypothalamus of the adult zebrafish brain. To further elucidate the roles of TRPV4, we manipulated TRPV4 protein expression and evaluated its ionoregulatory functions in zebrafish embryos. TRPV4 gene knockdown with morpholino oligonucleotides decreased ionic contents (Na+, Cl−, and Ca2+) of whole larvae and the H+-secreting function of larval skin of zebrafish. mRNA expressions of ionocyte-related transporters, including H+-ATPase, the epithelial Ca2+ channel, and the Na+-Cl− cotransporter, were also suppressed in trpv4 morphants. Numbers of ionocytes (H+-ATPase-rich cells and Na+-K+-ATPase-rich cells) and epidermal stem cells in zebrafish larval skin also decreased after trpv4 knockdown. Our results showed that TRPV4 modulates ion balance through the isotocin pathway.
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Affiliation(s)
- Sian-Tai Liu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Ming-Yi Chou
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Liang-Chun Wu
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
| | - Jiun-Lin Horng
- Department of Anatomy and Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Li-Yih Lin
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
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Shenton FC, Pyner S. Transient receptor potential vanilloid type 4 is expressed in vasopressinergic neurons within the magnocellular subdivision of the rat paraventricular nucleus of the hypothalamus. J Comp Neurol 2018; 526:3035-3044. [PMID: 30078222 PMCID: PMC6492187 DOI: 10.1002/cne.24514] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 01/28/2023]
Abstract
Changes in plasma osmolality can drive changes in the output from brain centres known to control cardiovascular homeostasis, such as the paraventricular nucleus of the hypothalamus (PVN). Within the PVN hypotonicity reduces the firing rate of parvocellular neurons, a neuronal pool known to be involved in modulating sympathetic vasomotor tone. Also present in the PVN is the transient receptor potential vanilloid type 4 (TRPV4) ion channel. Activation of TRPV4 within the PVN mimics the reduction in firing rate of the parvocellular neurons but it is unknown if these neurons express the channel. We used neuronal tracing and immunohistochemistry to investigate which neurons expressed the TRPV4 ion channel protein and its relationship with neurons known to play a role in plasma volume regulation. Spinally projecting preautonomic neurons within the PVN were labelled after spinal cord injection of FluoroGold (FG). This was followed by immunolabelling with anti‐TRPV4 antibody in combination with either anti‐oxytocin (OXT) or anti‐vasopressin (AVP). The TRPV4 ion channel was expressed on 63% of the vasopressinergic magnocellular neurosecretory cells found predominantly within the posterior magnocellular division of the PVN. Oxytocinergic neurons and FG labelled preautonomic neurons were present in the same location, but were distinct from the TRPV4/vasopressin expressing neurons. Vasopressinergic neurons within the supraoptic nucleus (SON) were also found to express TRPV4 and the fibres extending between the SON and PVN. In conclusion within the PVN, TRPV4 is well placed to respond to changes in osmolality by regulating vasopressin secretion, which in turn influences sympathetic output via preautonomic neurons.
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Affiliation(s)
- F C Shenton
- Department of Biosciences, Durham University, Durham, UK
| | - S Pyner
- Department of Biosciences, Durham University, Durham, UK
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