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Yuan X, Zhao X, Wang W, Li C. Mechanosensing by Piezo1 and its implications in the kidney. Acta Physiol (Oxf) 2024; 240:e14152. [PMID: 38682304 DOI: 10.1111/apha.14152] [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: 09/21/2023] [Revised: 03/27/2024] [Accepted: 04/15/2024] [Indexed: 05/01/2024]
Abstract
Piezo1 is an essential mechanosensitive transduction ion channel in mammals. Its unique structure makes it capable of converting mechanical cues into electrical and biological signals, modulating biological and (patho)physiological processes in a wide variety of cells. There is increasing evidence demonstrating that the piezo1 channel plays a vital role in renal physiology and disease conditions. This review summarizes the current evidence on the structure and properties of Piezo1, gating modulation, and pharmacological characteristics, with special focus on the distribution and (patho)physiological significance of Piezo1 in the kidney, which may provide insights into potential treatment targets for renal diseases involving this ion channel.
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Affiliation(s)
- Xi Yuan
- Department of Physiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Xiaoduo Zhao
- Department of Pathology, The First Affiliated Hospital, Zhejiang University, Hangzhou, China
| | - Weidong Wang
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Chunling Li
- Department of Physiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
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2
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Bihari S, Costell MH, Bouchier T, Behm DJ, Burgert M, Ye G, Bersten AD, Puukila S, Cavallaro E, Sprecher DL, Dixon DL. Evaluation of GSK2789917-induced TRPV4 inhibition in animal models of fluid induced lung injury. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024; 397:3461-3475. [PMID: 37966569 DOI: 10.1007/s00210-023-02821-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 10/26/2023] [Indexed: 11/16/2023]
Abstract
Administration of bolus intravenous fluids, common in pre-hospital and hospitalised patients, is associated with increased lung vascular permeability and mortality outside underlying disease states. In our laboratory, the induction of lung injury and oedema through rapid administration of intravenous fluid in rats was reduced by a non-specific antagonist of transient receptor potential vanilloid 4 (TRPV4) channels. The aims of this study were to determine the effect of selective TRPV4 inhibition on fluid-induced lung injury (FILI) and compare the potency of FILI inhibition to that of an established model of TRPV4 agonist-induced lung oedema. In a series of experiments, rats received specific TRPV4 inhibitor (GSK2789917) at high (15 μg/kg), medium (5 μg/kg) or low (2 μg/kg) dose or vehicle prior to induction of lung injury by intravenous infusion of TRPV4 agonist (GSK1016790) or saline. GSK1016790 significantly increased lung wet weight/body weight ratio by 96% and lung wet-to-dry weight ratio by 43% in vehicle pre-treated rats, which was inhibited by GSK2789917 in a dose-dependent manner (IC50 = 3 ng/mL). Similarly, in a single-dose study, bolus saline infusion significantly increased lung wet weight/body weight by 17% and lung wet-to-dry weight ratio by 15%, which was attenuated by high dose GSK2789917. However, in a final GSK2789917 dose-response study, inhibition did not reach significance and an inhibitory potency was not determined due to the lack of a clear dose-response. In the FILI model, TRPV4 may have a role in lung injury induced by rapid-fluid infusion, indicated by inconsistent amelioration with high dose TRPV4 antagonist.
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Affiliation(s)
- Shailesh Bihari
- College of Medicine and Public Health, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
- Intensive and Critical Care Unit, Flinders Medical Centre, Flinders Drive, Bedford Park, SA, 5042, Australia
| | - Melissa H Costell
- GlaxoSmithKline (GSK), 1250 South Collegeville Road, Collegeville, PA, 19426-0989, USA
| | - Tara Bouchier
- College of Medicine and Public Health, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - David J Behm
- GlaxoSmithKline (GSK), 1250 South Collegeville Road, Collegeville, PA, 19426-0989, USA
| | - Mark Burgert
- GlaxoSmithKline (GSK), 1250 South Collegeville Road, Collegeville, PA, 19426-0989, USA
| | - Guosen Ye
- GlaxoSmithKline (GSK), 1250 South Collegeville Road, Collegeville, PA, 19426-0989, USA
| | - Andrew D Bersten
- College of Medicine and Public Health, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
- Intensive and Critical Care Unit, Flinders Medical Centre, Flinders Drive, Bedford Park, SA, 5042, Australia
| | - Stephanie Puukila
- College of Medicine and Public Health, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Elena Cavallaro
- College of Medicine and Public Health, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia
| | - Dennis L Sprecher
- GlaxoSmithKline (GSK), 1250 South Collegeville Road, Collegeville, PA, 19426-0989, USA
| | - Dani-Louise Dixon
- College of Medicine and Public Health, Flinders University, GPO Box 2100, Adelaide, SA, 5001, Australia.
- Intensive and Critical Care Unit, Flinders Medical Centre, Flinders Drive, Bedford Park, SA, 5042, Australia.
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3
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Komagiri Y. Hydrogen sulfide induces Ca 2+ influx in the principal cells of rat cortical collecting ducts. Biochem Biophys Res Commun 2024; 699:149562. [PMID: 38277726 DOI: 10.1016/j.bbrc.2024.149562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 12/19/2023] [Accepted: 01/20/2024] [Indexed: 01/28/2024]
Abstract
Hydrogen sulfide (H2S) acts as a gas-signaling agent in various tissues. Although it has been reported that endogenous enzymes that generate H2S are expressed abundantly in the kidney, few reports examine cellular responses to H2S in renal tubular epithelial cells. In this study, we investigated the effects of NaHS, an H2S donor, and l-cysteine, a substrate for H2S production, on the principal cells of rat cortical collecting ducts (CCDs). NaHS increased the intracellular Ca2+ concentration ([Ca2+]i) in the principal cells. The removal of extracellular Ca2+ largely attenuated the [Ca2+]i response. The TRPV4 channel blocker significantly inhibited the effect of NaHS. Extracellular administration of l-cysteine also elicited a rise in [Ca2+]i. Prior treatment of CCDs with AOAA, an inhibitor of H2S production enzyme, l-cysteine-induced [Ca2+]i response was significantly reduced. These results suggest that not only exogenous H2S but also endogenously produced H2S triggers the extracellular influx pathway of Ca2+ in the principal cells of rat CCDs.
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Affiliation(s)
- You Komagiri
- Department of Physiology, Iwate Medical University School of Medicine, 1-1-1 Idaidori, Yahaba, Iwate, 028-3694, Japan.
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4
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Liu WW, Kinzy TG, Cooke Bailey JN, Xu Z, Hysi P, Wiggs JL. Mechanosensitive ion channel gene survey suggests potential roles in primary open angle glaucoma. Sci Rep 2023; 13:15871. [PMID: 37741866 PMCID: PMC10517927 DOI: 10.1038/s41598-023-43072-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 09/18/2023] [Indexed: 09/25/2023] Open
Abstract
Although glaucoma is a disease modulated by eye pressure, the mechanisms of pressure sensing in the eye are not well understood. Here, we investigated associations between mechanosensitive ion channel gene variants and primary open-angle glaucoma (POAG). Common (minor allele frequency > 5%) single nucleotide polymorphisms located within the genomic regions of 20 mechanosensitive ion channel genes in the K2P, TMEM63, PIEZO and TRP channel families were assessed using genotype data from the NEIGHBORHOOD consortium of 3853 cases and 33,480 controls. Rare (minor allele frequency < 1%) coding variants were assessed using exome array genotyping data for 2606 cases and 2606 controls. Association with POAG was analyzed using logistic regression adjusting for age and sex. Two rare PIEZO1 coding variants with protective effects were identified in the NEIGHBOR dataset: R1527H, (OR 0.17, P = 0.0018) and a variant that alters a canonical splice donor site, g.16-88737727-C-G Hg38 (OR 0.38, P = 0.02). Both variants showed similar effects in the UK Biobank and the R1527H also in the FinnGen database. Several common variants also reached study-specific thresholds for association in the NEIGHBORHOOD dataset. These results identify novel variants in several mechanosensitive channel genes that show associations with POAG, suggesting that these channels may be potential therapeutic targets.
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Affiliation(s)
- Wendy W Liu
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, 2370 Watson Court, Palo Alto, CA, 94303, USA.
| | - Tyler G Kinzy
- Department of Population and Quantitative Health Sciences, Cleveland Institute for Computational Biology, Case Western Reserve University, Cleveland, OH, USA
| | - Jessica N Cooke Bailey
- Department of Population and Quantitative Health Sciences, Cleveland Institute for Computational Biology, Case Western Reserve University, Cleveland, OH, USA
| | - Zihe Xu
- Department of Ophthalmology, King's College London, St. Thomas' Hospital, London, UK
| | - Pirro Hysi
- Department of Ophthalmology, King's College London, St. Thomas' Hospital, London, UK
- Department of Twin Research and Genetic Epidemiology, King's College London, St. Thomas' Hospital, London, UK
| | - Janey L Wiggs
- Massachusetts Eye and Ear, Harvard Medical School Boston, Boston, MA, USA
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Solari E, Marcozzi C, Negrini D, Moriondo A. Fluid Osmolarity Modulates the Rate of Spontaneous Contraction of Lymphatic Vessels and Lymph Flow by Means of a Cooperation between TRPV and VRAC Channels. BIOLOGY 2023; 12:1039. [PMID: 37508468 PMCID: PMC10376700 DOI: 10.3390/biology12071039] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/13/2023] [Accepted: 07/19/2023] [Indexed: 07/30/2023]
Abstract
Lymphatic vessels are capable of sustaining lymph formation and propulsion via an intrinsic mechanism based on the spontaneous contraction of the lymphatic muscle in the wall of lymphatic collectors. Exposure to a hyper- or hypo-osmolar environment can deeply affect the intrinsic contraction rate and therefore alter lymph flow. In this work, we aimed at defining the putative receptors underlying such a response. Functional experiments were conducted in ex vivo rat diaphragmatic specimens containing spontaneously contracting lymphatic vessels that were exposed to either hyper- or hypo-osmolar solutions. Lymphatics were challenged with blockers to TRPV4, TRPV1, and VRAC channels, known to respond to changes in osmolarity and/or cell swelling and expressed by lymphatic vessels. Results show that the normal response to a hyperosmolar environment is a steady decrease in the contraction rate and lymph flow and can be prevented by blocking TRPV1 channels with capsazepine. The response to a hyposmolar environment consists of an early phase of an increase in the contraction rate, followed by a decrease. The early phase is abolished by blocking VRACs with DCPIB, while blocking TRPV4 mainly resulted in a delay of the early response. Overall, our data suggest that the cooperation of the three channels can shape the response of lymphatic vessels in terms of contraction frequency and lymph flow, with a prominent role of TRPV1 and VRACs.
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Affiliation(s)
- Eleonora Solari
- Department of Medicine and Technological Innovation (DIMIT), Università degli Studi dell'Insubria, 21100 Varese, Italy
| | - Cristiana Marcozzi
- Department of Medicine and Technological Innovation (DIMIT), Università degli Studi dell'Insubria, 21100 Varese, Italy
| | - Daniela Negrini
- Department of Medicine and Technological Innovation (DIMIT), Università degli Studi dell'Insubria, 21100 Varese, Italy
| | - Andrea Moriondo
- Department of Medicine and Technological Innovation (DIMIT), Università degli Studi dell'Insubria, 21100 Varese, Italy
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Márquez-Nogueras KM, Knutila RM, Vuchkosvka V, Kuo IY. TRiPPing the sensors: The osmosensing pathway of Polycystin 2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.09.540007. [PMID: 37214815 PMCID: PMC10197615 DOI: 10.1101/2023.05.09.540007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mutations to polycystin-2 (PC2), a non-selective cation permeant transient receptor potential channel, results in polycystic kidney disease (PKD). Despite the disease relevance of PC2, the physiological agonist that activates PC2 has remained elusive. As one of the earliest symptoms in PKD is a urine concentrating deficiency, we hypothesized that shifts in osmolarity experienced by the collecting duct cells would activate PC2 and loss of PC2 would prevent osmosensing. We found that mice with inducible PC2 knocked out (KO) in renal tubules had dilute urine. Hyperosmotic stimuli induced a rise in endoplasmic reticulum (ER)-mediated cytosolic calcium which was absent in PC2 KO mice and PC2 KO cells. A pathologic point mutation that prevents ion flux through PC2 inhibited the calcium rise, pointing to the centrality of PC2 in the osmotic response. To understand how an extracellular stimulus activated ER-localized PC2, we examined microtubule-ER dynamics, and found that the osmotically induced calcium increase was preceded by microtubule destabilization. This was due to a novel interaction between PC2 and the microtubule binding protein MAP4 that tethers the microtubules to the ER. Finally, disruption of the MAP4-PC2 interaction prevented incorporation of the water channel aquaporin 2 following a hyperosmotic challenge, in part explaining the dilute urine. Our results demonstrate that MAP4-dependent microtubule stabilization of ER-resident PC2 is required for PC2 to participate in the osmosensing pathway. Moreover, osmolarity represents a bona fide physiological stimulus for ER-localized PC2 and loss of PC2 in renal epithelial cells impairs osmosensing ability and urine concentrating capacity.
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7
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Blazer-Yost BL. Consideration of Kinase Inhibitors for the Treatment of Hydrocephalus. Int J Mol Sci 2023; 24:ijms24076673. [PMID: 37047646 PMCID: PMC10094860 DOI: 10.3390/ijms24076673] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/27/2023] [Accepted: 03/29/2023] [Indexed: 04/07/2023] Open
Abstract
Hydrocephalus is a devastating condition characterized by excess cerebrospinal fluid (CSF) in the brain. Currently, the only effective treatment is surgical intervention, usually involving shunt placement, a procedure prone to malfunction, blockage, and infection that requires additional, often repetitive, surgeries. There are no long-term pharmaceutical treatments for hydrocephalus. To initiate an intelligent drug design, it is necessary to understand the biochemical changes underlying the pathology of this chronic condition. One potential commonality in the various forms of hydrocephalus is an imbalance in fluid–electrolyte homeostasis. The choroid plexus, a complex tissue found in the brain ventricles, is one of the most secretory tissues in the body, producing approximately 500 mL of CSF per day in an adult human. In this manuscript, two key transport proteins of the choroid plexus epithelial cells, transient receptor potential vanilloid 4 and sodium, potassium, 2 chloride co-transporter 1, will be considered. Both appear to play key roles in CSF production, and their inhibition or genetic manipulation has been shown to affect CSF volume. As with most transporters, these proteins are regulated by kinases. Therefore, specific kinase inhibitors are also potential targets for the development of pharmaceuticals to treat hydrocephalus.
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Affiliation(s)
- Bonnie L. Blazer-Yost
- Biology Department, Indiana University—Purdue University, 723 West Michigan Street, Indianapolis, IN 46202, USA
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8
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Pyrshev K, Stavniichuk A, Tomilin VN, Khayyat NH, Ren G, Kordysh M, Zaika O, Mamenko M, Pochynyuk O. TRPV4 functional status in cystic cells regulates cystogenesis in autosomal recessive polycystic kidney disease during variations in dietary potassium. Physiol Rep 2023; 11:e15641. [PMID: 36946001 PMCID: PMC10031299 DOI: 10.14814/phy2.15641] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 03/23/2023] Open
Abstract
Mechanosensitive TRPV4 channel plays a dominant role in maintaining [Ca2+ ]i homeostasis and flow-sensitive [Ca2+ ]i signaling in the renal tubule. Polycystic kidney disease (PKD) manifests as progressive cyst growth due to cAMP-dependent fluid secretion along with deficient mechanosensitivity and impaired TRPV4 activity. Here, we tested how regulation of renal TRPV4 function by dietary K+ intake modulates the rate of cystogenesis and mechanosensitive [Ca2+ ]i signaling in cystic cells of PCK453 rats, a homologous model of human autosomal recessive PKD (ARPKD). One month treatment with both high KCl (5% K+ ) and KB/C (5% K+ with bicarbonate/citrate) diets significantly increased TRPV4 levels when compared to control (0.9% K+ ). High KCl diet caused an increased TRPV4-dependent Ca2+ influx, and partial restoration of mechanosensitivity in freshly isolated monolayers of cystic cells. Unexpectedly, high KB/C diet induced an opposite effect by reducing TRPV4 activity and worsening [Ca2+ ]i homeostasis. Importantly, high KCl diet decreased cAMP, whereas high KB/C diet further increased cAMP levels in cystic cells (assessed as AQP2 distribution). At the systemic level, high KCl diet fed PCK453 rats had significantly lower kidney-to-bodyweight ratio and reduced cystic area. These beneficial effects were negated by a concomitant administration of an orally active TRPV4 antagonist, GSK2193874, resulting in greater kidney weight, accelerated cystogenesis, and augmented renal injury. High KB/C diet also exacerbated renal manifestations of ARPKD, consistent with deficient TRPV4 activity in cystic cells. Overall, we demonstrate that TRPV4 channel activity negatively regulates cAMP levels in cystic cells thus attenuating (high activity) or accelerating (low activity) ARPKD progression.
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Affiliation(s)
- Kyrylo Pyrshev
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Anna Stavniichuk
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Viktor N. Tomilin
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Naghmeh Hassanzadeh Khayyat
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Guohui Ren
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Mariya Kordysh
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Oleg Zaika
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
| | - Mykola Mamenko
- Department of PhysiologyAugusta UniversityAugustaGeorgiaUSA
| | - Oleh Pochynyuk
- Department of Integrative Biology and PharmacologyThe University of Texas Health Science Center at HoustonHoustonTexasUSA
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9
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Easson GWD, Savadipour A, Anandarajah A, Iannucci LE, Lake SP, Guilak F, Tang SY. Modulation of TRPV4 protects against degeneration induced by sustained loading and promotes matrix synthesis in the intervertebral disc. FASEB J 2023; 37:e22714. [PMID: 36583692 DOI: 10.1096/fj.202201388r] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/15/2022] [Accepted: 12/05/2022] [Indexed: 12/31/2022]
Abstract
While it is well known that mechanical signals can either promote or disrupt intervertebral disc (IVD) homeostasis, the molecular mechanisms for transducing mechanical stimuli are not fully understood. The transient receptor potential vanilloid 4 (TRPV4) ion channel activated in isolated IVD cells initiates extracellular matrix (ECM) gene expression, while TRPV4 ablation reduces cytokine production in response to circumferential stretching. However, the role of TRPV4 on ECM maintenance during tissue-level mechanical loading remains unknown. Using an organ culture model, we modulated TRPV4 function over both short- (hours) and long-term (days) and evaluated the IVDs' response. Activating TRPV4 with the agonist GSK101 resulted in a Ca2+ flux propagating across the cells within the IVD. Nuclear factor (NF)-κB signaling in the IVD peaked at 6 h following TRPV4 activation that subsequently resulted in higher interleukin (IL)-6 production at 7 days. These cellular responses were concomitant with the accumulation of glycosaminoglycans and increased hydration in the nucleus pulposus that culminated in higher stiffness of the IVD. Sustained compressive loading of the IVD resulted in elevated NF-κB activity, IL-6 and vascular endothelial growth factor A (VEGFA) production, and degenerative changes to the ECM. TRPV4 inhibition using GSK205 during loading mitigated the changes in inflammatory cytokines, protected against IVD degeneration, but could not prevent ECM disorganization due to mechanical damage in the annulus fibrosus. These results indicate TRPV4 plays an important role in both short- and long-term adaptations of the IVD to mechanical loading. The modulation of TRPV4 may be a possible therapeutic for preventing load-induced IVD degeneration.
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Affiliation(s)
- Garrett W D Easson
- Department of Mechanical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Alireza Savadipour
- Department of Mechanical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA.,Shriner's Hospital for Children - St. Louis, St. Louis, Missouri, USA
| | - Akila Anandarajah
- Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Leanne E Iannucci
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Spencer P Lake
- Department of Mechanical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Farshid Guilak
- Department of Mechanical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA.,Shriner's Hospital for Children - St. Louis, St. Louis, Missouri, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Simon Y Tang
- Department of Mechanical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Orthopaedic Surgery, Washington University in St. Louis, St. Louis, Missouri, USA.,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
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10
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Blazer-Yost BL. Following Ussing's legacy: from amphibian models to mammalian kidney and brain. Am J Physiol Cell Physiol 2022; 323:C1061-C1069. [PMID: 36036449 PMCID: PMC9529261 DOI: 10.1152/ajpcell.00303.2022] [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: 07/12/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 11/22/2022]
Abstract
Professor Hans H. Ussing (1911-2000) was one of the founding members of the field of epithelial cell biology. He is most famous for the electrophysiological technique that he developed to measure electrogenic ion flux across epithelial tissues. Ussing-style electrophysiology has been applied to multiple tissues and has informed fields as diverse as amphibian biology and medicine. In the latter, this technique has contributed to a basic understanding of maladies such as hypertension, polycystic kidney disease, cystic fibrosis, and diarrheal diseases to mention but a few. In addition to this valuable contribution to biological methods, Prof. Ussing also provided strong evidence for the concept of active transport several years before the elucidation of Na+K+ATPase. In addition, he provided cell biologists with the important concept of polarized epithelia with specific and different transporters found in the apical and basolateral membranes, thus providing these cells with the ability to conduct directional, active and passive transepithelial transport. My studies have used Ussing chamber electrophysiology to study the toad urinary bladder, an amphibian cell line, renal cell lines, and, most recently, choroid plexus cell lines. This technique has formed the basis of our in vitro mechanistic studies that are used in an iterative manner with animal models to better understand disease progress and treatment. I was honored to be invited to deliver the 2022 Hans Ussing Lecture sponsored by the Epithelial Transport Group of the American Physiological Society. This manuscript is a version of the material presented in that lecture.
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Affiliation(s)
- Bonnie L Blazer-Yost
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
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11
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van Setten GB. GPR-68 in human lacrimal gland. Detection and possible role in the pathogenesis of dry eye disease. J Fr Ophtalmol 2022; 45:921-927. [DOI: 10.1016/j.jfo.2022.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 01/25/2022] [Accepted: 02/01/2022] [Indexed: 11/16/2022]
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12
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Mechanisms of ion transport regulation by HNF1β in the kidney: beyond transcriptional regulation of channels and transporters. Pflugers Arch 2022; 474:901-916. [PMID: 35554666 PMCID: PMC9338905 DOI: 10.1007/s00424-022-02697-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 01/01/2023]
Abstract
Hepatocyte nuclear factor 1β (HNF1β) is a transcription factor essential for the development and function of the kidney. Mutations in and deletions of HNF1β cause autosomal dominant tubule interstitial kidney disease (ADTKD) subtype HNF1β, which is characterized by renal cysts, diabetes, genital tract malformations, and neurodevelopmental disorders. Electrolyte disturbances including hypomagnesemia, hyperuricemia, and hypocalciuria are common in patients with ADTKD-HNF1β. Traditionally, these electrolyte disturbances have been attributed to HNF1β-mediated transcriptional regulation of gene networks involved in ion transport in the distal part of the nephron including FXYD2, CASR, KCNJ16, and FXR. In this review, we propose additional mechanisms that may contribute to the electrolyte disturbances observed in ADTKD-HNF1β patients. Firstly, kidney development is severely affected in Hnf1b-deficient mice. HNF1β is required for nephron segmentation, and the absence of the transcription factor results in rudimentary nephrons lacking mature proximal tubule, loop of Henle, and distal convoluted tubule cluster. In addition, HNF1β is proposed to be important for apical-basolateral polarity and tight junction integrity in the kidney. Interestingly, cilia formation is unaffected by Hnf1b defects in several models, despite the HNF1β-mediated transcriptional regulation of many ciliary genes. To what extent impaired nephron segmentation, apical-basolateral polarity, and cilia function contribute to electrolyte disturbances in HNF1β patients remains elusive. Systematic phenotyping of Hnf1b mouse models and the development of patient-specific kidney organoid models will be essential to advance future HNF1β research.
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Kleene SJ. Regenerative Calcium Currents in Renal Primary Cilia. Front Physiol 2022; 13:894518. [PMID: 35620606 PMCID: PMC9127361 DOI: 10.3389/fphys.2022.894518] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022] Open
Abstract
Polycystic kidney disease (PKD) is a leading cause of end-stage renal disease. PKD arises from mutations in proteins, one a Ca2+-conducting channel, expressed in the primary cilia of renal epithelial cells. A common hypothesis is that Ca2+ entering through ciliary ion channels may reduce cystogenesis. The cilia have at least two Ca2+-conducting channels: polycystin-2 (PC2) and TRPV4 (transient receptor potential (TRP) cation channel, subfamily V, member 4), but how substantially they can increase intraciliary Ca2+ is unknown. By recording channel activities in isolated cilia, conditions are identified under which the channels can increase free Ca2+ within the cilium by at least 500-fold through regenerative (positive-feedback) signaling. Ca2+ that has entered through a channel can activate the channel internally, which increases the Ca2+ influx, and so on. Regenerative signaling is favored when the concentration of the Ca2+ buffer is reduced or when a slower buffer is used. Under such conditions, the Ca2+ that enters the cilium through a single PC2 channel is sufficient to almost fully activate that same channel. Regenerative signaling is not detectable with reduced external Ca2+. Reduced buffering also allows regenerative signaling through TRPV4 channels, but not through TRPM4 (TRP subfamily M, member 4) channels, which are activated by Ca2+ but do not conduct it. On a larger scale, Ca2+ that enters through TRPV4 channels can cause secondary activation of PC2 channels. I discuss the likelihood of regenerative ciliary Ca2+ signaling in vivo, a possible mechanism for its activation, and how it might relate to cystogenesis.
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Affiliation(s)
- Steven J. Kleene
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH, United States
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14
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Evolving concepts of TRPV4 in controlling flow-sensitivity of the renal nephron. CURRENT TOPICS IN MEMBRANES 2022; 89:75-94. [DOI: 10.1016/bs.ctm.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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15
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Dave N, Cetiner U, Arroyo D, Fonbuena J, Tiwari M, Barrera P, Lander N, Anishkin A, Sukharev S, Jimenez V. A novel mechanosensitive channel controls osmoregulation, differentiation, and infectivity in Trypanosoma cruzi. eLife 2021; 10:67449. [PMID: 34212856 PMCID: PMC8282336 DOI: 10.7554/elife.67449] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 07/01/2021] [Indexed: 12/19/2022] Open
Abstract
The causative agent of Chagas disease undergoes drastic morphological and biochemical modifications as it passes between hosts and transitions from extracellular to intracellular stages. The osmotic and mechanical aspects of these cellular transformations are not understood. Here we identify and characterize a novel mechanosensitive channel in Trypanosoma cruzi (TcMscS) belonging to the superfamily of small-conductance mechanosensitive channels (MscS). TcMscS is activated by membrane tension and forms a large pore permeable to anions, cations, and small osmolytes. The channel changes its location from the contractile vacuole complex in epimastigotes to the plasma membrane as the parasites develop into intracellular amastigotes. TcMscS knockout parasites show significant fitness defects, including increased cell volume, calcium dysregulation, impaired differentiation, and a dramatic decrease in infectivity. Our work provides mechanistic insights into components supporting pathogen adaptation inside the host, thus opening the exploration of mechanosensation as a prerequisite for protozoan infectivity.
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Affiliation(s)
- Noopur Dave
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, United States
| | - Ugur Cetiner
- Department of Biology, University of Maryland, College Park, United States
| | - Daniel Arroyo
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, United States
| | - Joshua Fonbuena
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, United States
| | - Megna Tiwari
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, United States
| | - Patricia Barrera
- Departmento de Biología, Facultad de Ciencias Exactas y Naturales, Instituto de Histologia y Embriologia IHEM-CONICET, Facultad de Medicina, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Noelia Lander
- Department of Biological Sciences, University of Cincinnati, Cincinnati, United States
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, United States
| | - Sergei Sukharev
- Department of Biology, University of Maryland, College Park, United States
| | - Veronica Jimenez
- Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, United States
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16
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Sakich NB, Tattersall GJ. Bearded dragons (Pogona vitticeps) with reduced scalation lose water faster but do not have substantially different thermal preferences. J Exp Biol 2021; 224:269179. [PMID: 34137892 DOI: 10.1242/jeb.234427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 05/24/2021] [Indexed: 01/11/2023]
Abstract
Whether scales reduce cutaneous evaporative water loss in lepidosaur reptiles (Superorder Lepidosauria) such as lizards and snakes has been a contentious issue for nearly half a century. Furthermore, while many studies have looked at whether dehydration affects thermal preference in lepidosaurs, far fewer have examined whether normally hydrated lepidosaurs can assess their instantaneous rate of evaporative water loss and adjust their thermal preference to compensate in an adaptive manner. We tested both of these hypotheses using three captive-bred phenotypes of bearded dragon (Pogona vitticeps) sourced from the pet trade: 'wild-types' with normal scalation, 'leatherbacks' exhibiting scales of reduced prominence, and scaleless bearded dragons referred to as 'silkbacks'. Silkbacks on average lost water evaporatively at about twice the rate that wild-types did. Leatherbacks on average were closer in their rates of evaporative water loss to silkbacks than they were to wild-types. Additionally, very small (at most ∼1°C) differences in thermal preference existed between the three phenotypes that were not statistically significant. This suggests a lack of plasticity in thermal preference in response to an increase in the rate of evaporative water loss, and may be reflective of a thermal 'strategy' as employed by thermoregulating bearded dragons that prioritises immediate thermal benefits over the threat of future dehydration. The results of this study bolster an often-discounted hypothesis regarding the present adaptive function of scales and have implications for the applied fields of animal welfare and conservation.
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Affiliation(s)
- Nicholas B Sakich
- Department of Biological Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
| | - Glenn J Tattersall
- Department of Biological Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, ON L2S 3A1, Canada
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17
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TRPM7 is an essential regulator for volume-sensitive outwardly rectifying anion channel. Commun Biol 2021; 4:599. [PMID: 34017036 PMCID: PMC8137958 DOI: 10.1038/s42003-021-02127-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 04/20/2021] [Indexed: 02/03/2023] Open
Abstract
Animal cells can regulate their volume after swelling by the regulatory volume decrease (RVD) mechanism. In epithelial cells, RVD is attained through KCl release mediated via volume-sensitive outwardly rectifying Cl- channels (VSOR) and Ca2+-activated K+ channels. Swelling-induced activation of TRPM7 cation channels leads to Ca2+ influx, thereby stimulating the K+ channels. Here, we examined whether TRPM7 plays any role in VSOR activation. When TRPM7 was knocked down in human HeLa cells or knocked out in chicken DT40 cells, not only TRPM7 activity and RVD efficacy but also VSOR activity were suppressed. Heterologous expression of TRPM7 in TRPM7-deficient DT40 cells rescued both VSOR activity and RVD, accompanied by an increase in the expression of LRRC8A, a core molecule of VSOR. TRPM7 exerts the facilitating action on VSOR activity first by enhancing molecular expression of LRRC8A mRNA through the mediation of steady-state Ca2+ influx and second by stabilizing the plasmalemmal expression of LRRC8A protein through the interaction between LRRC8A and the C-terminal domain of TRPM7. Therefore, TRPM7 functions as an essential regulator of VSOR activity and LRRC8A expression.
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18
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Knecht RS, Bucher CH, Van Linthout S, Tschöpe C, Schmidt-Bleek K, Duda GN. Mechanobiological Principles Influence the Immune Response in Regeneration: Implications for Bone Healing. Front Bioeng Biotechnol 2021; 9:614508. [PMID: 33644014 PMCID: PMC7907627 DOI: 10.3389/fbioe.2021.614508] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 01/22/2021] [Indexed: 12/13/2022] Open
Abstract
A misdirected or imbalanced local immune composition is often one of the reasons for unsuccessful regeneration resulting in scarring or fibrosis. Successful healing requires a balanced initiation and a timely down-regulation of the inflammation for the re-establishment of a biologically and mechanically homeostasis. While biomaterial-based approaches to control local immune responses are emerging as potential new treatment options, the extent to which biophysical material properties themselves play a role in modulating a local immune niche response has so far been considered only occasionally. The communication loop between extracellular matrix, non-hematopoietic cells, and immune cells seems to be specifically sensitive to mechanical cues and appears to play a role in the initiation and promotion of a local inflammatory setting. In this review, we focus on the crosstalk between ECM and its mechanical triggers and how they impact immune cells and non-hematopoietic cells and their crosstalk during tissue regeneration. We realized that especially mechanosensitive receptors such as TRPV4 and PIEZO1 and the mechanosensitive transcription factor YAP/TAZ are essential to regeneration in various organ settings. This indicates novel opportunities for therapeutic approaches to improve tissue regeneration, based on the immune-mechanical principles found in bone but also lung, heart, and skin.
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Affiliation(s)
- Raphael S Knecht
- Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Christian H Bucher
- Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health Center for Regenerative Therapies, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sophie Van Linthout
- Berlin Institute of Health Center for Regenerative Therapies, Charité-Universitätsmedizin Berlin, Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany
| | - Carsten Tschöpe
- Berlin Institute of Health Center for Regenerative Therapies, Charité-Universitätsmedizin Berlin, Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, Berlin, Germany.,Department of Cardiology, Charite'-Universitätsmedizin Berlin, Berlin, Germany
| | - Katharina Schmidt-Bleek
- Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health Center for Regenerative Therapies, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Georg N Duda
- Julius Wolff Institute and Center for Musculoskeletal Surgery, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health Center for Regenerative Therapies, Charité-Universitätsmedizin Berlin, Berlin, Germany
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19
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Wu Y, Qi J, Wu C, Rong W. Emerging roles of the TRPV4 channel in bladder physiology and dysfunction. J Physiol 2021; 599:39-47. [PMID: 33052604 DOI: 10.1113/jp279776] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 10/06/2020] [Indexed: 12/17/2022] Open
Abstract
The transient receptor potential vanilloid type 4, TRPV4, is a polymodal cation channel which can be activated by diverse stimuli including mechanical, thermal and chemical cues. In the urinary bladder, TRPV4 is not only abundantly expressed in the urothelium but may also be localized in subepithelium, detrusor smooth muscles and afferent neurons. Emerging evidence indicates that the TRPV4 channel plays a sensory role in the uroepithelium, where it may regulate the release of sensory mediators such as ATP, which in turn modulates afferent nerve activity in response to bladder filling during the urination cycle. TRPV4 may also directly regulate detrusor contractility and the urothelial barrier function. Altered TRPV4 expression has been detected in various pathological bladder conditions. As such, TRPV4 may be a promising therapeutic target for bladder dysfunctions.
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Affiliation(s)
- Yanyuan Wu
- Department of Urology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Jun Qi
- Department of Urology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Changhao Wu
- School of Biosciences and Medicine, University of Surrey, Guildford, UK
| | - Weifang Rong
- Department of Urology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- Department of Anatomy and Physiology, Shanghai Jiaotong University School of Medicine, Shanghai, China
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20
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Gualdani R, Seghers F, Yerna X, Schakman O, Tajeddine N, Achouri Y, Tissir F, Devuyst O, Gailly P. Mechanical activation of TRPV4 channels controls albumin reabsorption by proximal tubule cells. Sci Signal 2020; 13:13/653/eabc6967. [DOI: 10.1126/scisignal.abc6967] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Defects in protein reabsorption by the proximal tubule are toxic for epithelial cells in the nephron and may result in nephropathy. In this study, we showed that the ion channel TRPV4 modulated the endocytosis of albumin and low–molecular weight proteins in the proximal tubule. TRPV4 was found at the basolateral side of proximal tubule cells, and its mechanical activation by cell stretching induced Ca2+ entry into the cytosol, which promoted endocytosis. Trpv4−/− mice presented with mild proximal tubule dysfunction under basal conditions. To challenge endocytic function, the permeability of the glomerular filter was altered by systemic delivery of angiotensin II. The proteinuria induced by this treatment was more severe in Trpv4−/− than in Trpv4+/+ mice. Injecting antibodies against the glomerular basement membrane to induce glomerulonephritis is a more pathophysiologically relevant method of impairing glomerular filter permeability. Albuminuria was more severe in mice that lacked TRPV4 specifically in the proximal tubule than in control mice. These results emphasize the importance of TRPV4 in sensing pressure in the proximal tubule in response to variations in the amount of ultrafiltrate and unveil a mechanism that controls protein reabsorption.
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Affiliation(s)
- Roberta Gualdani
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
| | - François Seghers
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
| | - Xavier Yerna
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
| | - Olivier Schakman
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
| | - Nicolas Tajeddine
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
| | - Younès Achouri
- Université catholique de Louvain, de Duve Institute, Transgenic Core Facility, av. Hippocrate 75/B1.75.09, B-1200 Brussels, Belgium
| | - Fadel Tissir
- Université catholique de Louvain, Institute of Neuroscience, Developmental Neurobiology, av. Hippocrate 73/B1.73.16, B-1200 Brussels, Belgium
| | - Olivier Devuyst
- University of Zurich, Institute of Physiology, Winterthurerstr. 190, CH-8057 Zurich, Switzerland
| | - Philippe Gailly
- Université catholique de Louvain, Institute of Neuroscience, Cell Physiology, av. Mounier 53/B1.53.17, B-1200 Brussels, Belgium
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21
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Hochstetler AE, Smith HM, Preston DC, Reed MM, Territo PR, Shim JW, Fulkerson D, Blazer-Yost BL. TRPV4 antagonists ameliorate ventriculomegaly in a rat model of hydrocephalus. JCI Insight 2020; 5:137646. [PMID: 32938829 PMCID: PMC7526552 DOI: 10.1172/jci.insight.137646] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 08/19/2020] [Indexed: 11/27/2022] Open
Abstract
Hydrocephalus is a serious condition that impacts patients of all ages. The standards of care are surgical options to divert, or inhibit production of, cerebrospinal fluid; to date, there are no effective pharmaceutical treatments, to our knowledge. The causes vary widely, but one commonality of this condition is aberrations in salt and fluid balance. We have used a genetic model of hydrocephalus to show that ventriculomegaly can be alleviated by inhibition of the transient receptor potential vanilloid 4, a channel that is activated by changes in osmotic balance, temperature, pressure and inflammatory mediators. The TRPV4 antagonists do not appear to have adverse effects on the overall health of the WT or hydrocephalic animals. Two distinct TRPV4 antagonists ameliorate ventriculomegaly in a genetic rat model of severe postnatal hydrocephalus, with no apparent adverse effects on animals.
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Affiliation(s)
| | - Hillary M Smith
- Department of Biology, Indiana University, Purdue University, Indianapolis, Indiana, USA
| | - Daniel C Preston
- Department of Biology, Indiana University, Purdue University, Indianapolis, Indiana, USA
| | - Makenna M Reed
- Department of Biology, Indiana University, Purdue University, Indianapolis, Indiana, USA
| | - Paul R Territo
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Joon W Shim
- Department of Biology, Indiana University, Purdue University, Indianapolis, Indiana, USA
| | | | - Bonnie L Blazer-Yost
- Department of Biology, Indiana University, Purdue University, Indianapolis, Indiana, USA
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22
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Hu W, Ding Y, Li Q, shi R, He Y. Transient receptor potential vanilloid 4 channels as therapeutic targets in diabetes and diabetes-related complications. J Diabetes Investig 2020; 11:757-769. [PMID: 32129549 PMCID: PMC7378409 DOI: 10.1111/jdi.13244] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 01/21/2020] [Accepted: 02/27/2020] [Indexed: 12/12/2022] Open
Abstract
With an estimated 425 million diabetes patients worldwide in 2019, type 2 diabetes has reached a pandemic proportion and represents a major unmet medical need. A key determinant of the development and progression of type 2 diabetes is pancreatic -cell dysfunction, including the loss of cell mass, the impairment of insulin biosynthesis and inadequate exocytosis. Recent studies have shown that transient receptor potential vanilloid 4 (TRPV4), a Ca2+ -permeable non-selective cation channel, is involved in -cell replication, insulin production and secretion. TRPV4 agonists have insulinotropic activity in pancreatic -cell lines, but the prolonged activation of TRPV4 leads to -cell dysfunction and death. In addition, TRPV4 is involved in a wide variety of pathophysiological activities, and has been reported to play an important role in diabetes-related complications, such as obesity, cardiovascular diseases, diabetic retinopathy, nephropathy and neuropathy. In a rodent type 2 diabetes model, Trpv4 agonists promote vasodilation and improve cardiovascular function, whereas Trpv4 antagonists reduce high-fat diet-induced obesity, insulin resistance, diabetic nephropathy, retinopathy and neuropathy. These findings raise interest in using TRPV4 as a therapeutic target for type 2 diabetes. In this review, we intend to summarize the latest findings regarding the role of TRPV4 in diabetes as well as diabetes-related conditions, and to evaluate its potential as a therapeutic target for diabetes and diabetes-related diseases.
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Affiliation(s)
- Wei Hu
- Department of Epidemiology and Medical StatisticsInstitute of Medical Systems BiologyGuangdong Medical UniversityDongguanChina
| | - Yuanlin Ding
- Department of Epidemiology and Medical StatisticsInstitute of Medical Systems BiologyGuangdong Medical UniversityDongguanChina
| | - Qingqing Li
- Department of Epidemiology and Medical StatisticsInstitute of Medical Systems BiologyGuangdong Medical UniversityDongguanChina
| | - Rou shi
- Department of Epidemiology and Medical StatisticsInstitute of Medical Systems BiologyGuangdong Medical UniversityDongguanChina
| | - Yuqing He
- Department of Epidemiology and Medical StatisticsInstitute of Medical Systems BiologyGuangdong Medical UniversityDongguanChina
- Liaobu HospitalGuangdong Medical UniversityDongguanChina
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23
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The Mechanical Microenvironment in Breast Cancer. Cancers (Basel) 2020; 12:cancers12061452. [PMID: 32503141 PMCID: PMC7352870 DOI: 10.3390/cancers12061452] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/27/2020] [Accepted: 06/01/2020] [Indexed: 01/22/2023] Open
Abstract
Mechanotransduction is the interpretation of physical cues by cells through mechanosensation mechanisms that elegantly translate mechanical stimuli into biochemical signaling pathways. While mechanical stress and their resulting cellular responses occur in normal physiologic contexts, there are a variety of cancer-associated physical cues present in the tumor microenvironment that are pathological in breast cancer. Mechanistic in vitro data and in vivo evidence currently support three mechanical stressors as mechanical modifiers in breast cancer that will be the focus of this review: stiffness, interstitial fluid pressure, and solid stress. Increases in stiffness, interstitial fluid pressure, and solid stress are thought to promote malignant phenotypes in normal breast epithelial cells, as well as exacerbate malignant phenotypes in breast cancer cells.
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24
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Michalick L, Kuebler WM. TRPV4-A Missing Link Between Mechanosensation and Immunity. Front Immunol 2020; 11:413. [PMID: 32210976 PMCID: PMC7076180 DOI: 10.3389/fimmu.2020.00413] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 02/21/2020] [Indexed: 12/21/2022] Open
Abstract
Transient receptor potential vanilloid-type 4 (TRPV4) cation channel is widely expressed in all tissues as well as in immune cells and its function as mechanosensitive Ca2+ channel seems to be conserved throughout all mammalian species. Of late, emerging evidence has implicated TRPV4 in the activation and differentiation of innate immune cells, especially in neutrophils, monocytes, and macrophages. As such, TRPV4 has been shown to mediate neutrophil adhesion and chemotaxis, as well as production of reactive oxygen species in response to pro-inflammatory stimuli. In macrophages, TRPV4 mediates formation of both reactive oxygen and nitrogen species, and regulates phagocytosis, thus facilitating bacterial clearance and resolution of infection. Importantly, TRPV4 may present a missing link between mechanical forces and immune responses. This connection has been exemplary highlighted by the demonstrated role of TRPV4 in macrophage activation and subsequent induction of lung injury following mechanical overventilation. Mechanosensation via TRPV4 is also expected to activate innate immune cells and establish a pro-inflammatory loop in fibrotic diseases with increased deposition of extracellular matrix (ECM) and substrate stiffness. Likewise, TRPV4 may be activated by cell migration through the endothelium or the extracellular matrix, or even by circulating immune cells squeezing through the narrow passages of the pulmonary or systemic capillary bed, a process that has recently been linked to neutrophil priming and depriming. Here, we provide an overview over the emerging role of TRPV4 in innate immune responses and highlight two distinct modes for the activation of TRPV4 by either mechanical forces ("mechanoTRPV4") or by pathogens ("immunoTRPV4").
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Affiliation(s)
- Laura Michalick
- Institute of Physiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Institute of Physiology, Berlin Institute of Health, Berlin, Germany
| | - Wolfgang M. Kuebler
- Institute of Physiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Institute of Physiology, Berlin Institute of Health, Berlin, Germany
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25
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Verschuren EHJ, Castenmiller C, Peters DJM, Arjona FJ, Bindels RJM, Hoenderop JGJ. Sensing of tubular flow and renal electrolyte transport. Nat Rev Nephrol 2020; 16:337-351. [DOI: 10.1038/s41581-020-0259-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/06/2020] [Indexed: 02/06/2023]
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26
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Abstract
Since its discovery, aldosterone and ion modulation have been entwined. While scientific investigations throughout the decades have emphasized aldosterone's connection to Na+, K+, and H+ homeostasis, more recent research has demonstrated a relationship between aldosterone and Mg2+, Ca2+, and Cl- homeostasis. The mechanisms connecting aldosterone to ion regulation frequently involve ion channels; the membrane localized proteins containing at least one aqueous pore for ion conduction. In order to precisely control intracellular or intraorganelle ion concentrations, ion channels have evolved highly specific regions within the conduction pore that select ions by charge, size, and/or dehydration energy requirement, meaning aldosterone must be able to modulate multiple ion channels to regulate the many ions described above. The list of ion channels presently connected to aldosterone includes ENaC (Na+), ROMK/BK (K+), TRPV4/5/6 (Ca2+), TRPM7/6 (Mg2+), and ClC-K/CFTR (Cl-), among others. This list is only expected to grow over time, as the promiscuity of aldosterone becomes more understood.
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Affiliation(s)
| | - Rhian M Touyz
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Alvin Shrier
- Department of Physiology, McGill University, Montreal, QC, Canada.
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27
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Li Y, Hu H, O'Neil RG. Caveolae facilitate TRPV4-mediated Ca 2+ signaling and the hierarchical activation of Ca 2+-activated K + channels in K +-secreting renal collecting duct cells. Am J Physiol Renal Physiol 2018; 315:F1626-F1636. [PMID: 30207167 DOI: 10.1152/ajprenal.00076.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Transient receptor potential cation channel subfamily V member 4 (TRPV4)-mediated Ca2+ signaling induces early activation of small/intermediate Ca2+-activated K+ channels, SK3 (KCNN3) and IK1 (KCNN4), which leads to membrane hyperpolarization and enhanced Ca2+ influx, which is critical for subsequent activation of the large conductance Ca2+-activated K+ channel BK (KCNMA1) and K+ secretion in kidney cortical collecting duct (CCD) cells. The focus of the present study was to determine if such coordinated hierarchical/sequential activation of these channels in CCD was orchestrated within caveolae, a known microcompartment underlying selective Ca2+-signaling events in other cells. In K+-secreting mouse principal cell (PC) line, mCCDcl1 cells, knockdown of caveolae caveolin-1 (CAV-1) depressed TRPV4-mediated Ca2+ signaling and activation of SK3, intermediate conductance channel (IK1), and BK. Immunofluorescence colocalization analysis and coimmunoprecipitation assays demonstrated direct coupling of TRPV4 with each of the KCa channels in both mCCDcl1 and whole mouse kidney homogenates. Likewise, extending this analysis to CAV-1 demonstrates colocalization and direct coupling of CAV-1 with TRPV4, SK3, IK1, and BK, providing strong support for coupling of the channels in caveolae microdomains. Furthermore, differential expression of CAV-1 along the CCD was apparent where CAV-1 was strongly expressed within and along the cell borders of kidney PCs and intercalated cells (ICs), although significantly less in ICs. It is concluded that caveolae provide a key microdomain in PCs and ICs for coupling of TRPV4 with SK3, IK1, and BK that directly contributes to TRPV4-mediated Ca2+ signaling in these domains leading to rapid and sequential coupling of TRPV4-SK3/IK1-BK that may play a central role in mediating Ca2+-dependent regulation of BK and K+ secretion.
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Affiliation(s)
- Yue Li
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, Texas
| | - Hongxiang Hu
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, Texas
| | - Roger G O'Neil
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston , Houston, Texas
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Abstract
Transient Receptor Potential (TRP) channels are evolutionarily conserved integral membrane proteins. The mammalian TRP superfamily of ion channels consists of 28 cation permeable channels that are grouped into six subfamilies based on sequence homology (Fig. 6.1). The canonical TRP (TRPC) subfamily is known for containing the founding member of mammalian TRP channels. The vanilloid TRP (TRPV) subfamily has been extensively studied due to the heat sensitivity of its founding member. The melastatin-related TRP (TRPM) subfamily includes some of the few known bi-functional ion channels, which contain functional enzymatic domains. The ankyrin TRP (TRPA) subfamily consists of a single chemo-nociceptor that has been proposed to be a target for analgesics. The mucolipin TRP (TRPML) subfamily channels are found primarily in intracellular compartments and were discovered based on their critical role in type IV mucolipidosis (ML-IV). The polycystic TRP (TRPP) subfamily is a diverse group of proteins implicated in autosomal dominant polycystic kidney disease (ADPKD). Overall, this superfamily of channels is involved in a vast array of physiological and pathophysiological processes making the study of these channels imperative to our understanding of subcellular biochemistry.
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Affiliation(s)
- Amrita Samanta
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Physiology and Biophysics School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Taylor E T Hughes
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Vera Y Moiseenkova-Bell
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Department of Physiology and Biophysics School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
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29
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Tomilin V, Reif GA, Zaika O, Wallace DP, Pochynyuk O. Deficient transient receptor potential vanilloid type 4 function contributes to compromised [Ca 2+] i homeostasis in human autosomal-dominant polycystic kidney disease cells. FASEB J 2018; 32:4612-4623. [PMID: 29553832 DOI: 10.1096/fj.201701535rr] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Autosomal-dominant polycystic kidney disease (ADPKD) is a devastating disorder that is characterized by a progressive decline in renal function as a result of the development of fluid-filled cysts. Defective flow-mediated [Ca2+]i responses and disrupted [Ca2+]i homeostasis have been repeatedly associated with cyst progression in ADPKD. We have previously demonstrated that the transient receptor potential vanilloid type 4 (TRPV4) channel is imperative for flow-mediated [Ca2+]i responses in murine distal renal tubule cells. To determine whether compromised TRPV4 function contributes to aberrant Ca2+ regulation in ADPKD, we assessed TRPV4 function in primary cells that were cultured from ADPKD and normal human kidneys (NHKs). Single-channel TRPV4 activity and TRPV4-dependent Ca2+ influxes were drastically reduced in ADPKD cells, which correlated with distorted [Ca2+]i signaling. Whereas total TRPV4 protein levels were comparable in NHK and ADPKD cells, we detected a marked decrease in TRPV4 glycosylation in ADPKD cells. Tunicamycin-induced deglycosylation inhibited TRPV4 activity and compromised [Ca2+]i signaling in NHK cells. Overall, we demonstrate that TRPV4 glycosylation and channel activity are diminished in human ADPKD cells compared with NHK cells, and that this contributes significantly to the distorted [Ca2+]i dynamics. We propose that TRPV4 stimulation may be beneficial for restoring [Ca2+]i homeostasis in cyst cells, thereby interfering with ADPKD progression.-Tomilin, V., Reif, G. A., Zaika, O., Wallace, D. P., Pochynyuk, O. Deficient transient receptor potential vanilloid type 4 function contributes to compromised [Ca2+]i homeostasis in human autosomal-dominant polycystic kidney disease cells.
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Affiliation(s)
- Viktor Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA; and
| | - Gail A Reif
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA; and
| | - Darren P Wallace
- The Jared Grantham Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas, USA; and
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30
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Aldosterone, SGK1, and ion channels in the kidney. Clin Sci (Lond) 2018; 132:173-183. [PMID: 29352074 PMCID: PMC5817097 DOI: 10.1042/cs20171525] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 12/15/2017] [Accepted: 12/19/2017] [Indexed: 12/14/2022]
Abstract
Hyperaldosteronism, a common cause of hypertension, is strongly connected to Na+, K+, and Mg2+ dysregulation. Owing to its steroidal structure, aldosterone is an active transcriptional modifier when bound to the mineralocorticoid receptor (MR) in cells expressing the enzyme 11β-hydroxysteroid dehydrogenase 2, such as those comprising the aldosterone-sensitive distal nephron (ASDN). One such up-regulated protein, the ubiquitous serum and glucocorticoid regulated kinase 1 (SGK1), has the capacity to modulate the surface expression and function of many classes of renal ion channels, including those that transport Na+ (ENaC), K+ (ROMK/BK), Ca2+ (TRPV4/5/6), Mg2+ (TRPM7/6), and Cl− (ClC-K, CFTR). Here, we discuss the mechanisms by which ASDN expressed channels are up-regulated by SGK1, while highlighting newly discovered pathways connecting aldosterone to nonselective cation channels that are permeable to Mg2+ (TRPM7) or Ca2+ (TRPV4).
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31
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Transient Receptor Potential Vanilloid 4 and Serum Glucocorticoid-regulated Kinase 1 Are Critical Mediators of Lung Injury in Overventilated Mice In Vivo. Anesthesiology 2017; 126:300-311. [PMID: 27861175 DOI: 10.1097/aln.0000000000001443] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Mechanical ventilation can cause lung endothelial barrier failure and inflammation cumulating in ventilator-induced lung injury. Yet, underlying mechanotransduction mechanisms remain unclear. Here, the authors tested the hypothesis that activation of the mechanosensitive Ca channel transient receptor potential vanilloid (TRPV4) by serum glucocorticoid-regulated kinase (SGK) 1 may drive the development of ventilator-induced lung injury. METHODS Mice (total n = 54) were ventilated for 2 h with low (7 ml/kg) or high (20 ml/kg) tidal volumes and assessed for signs of ventilator-induced lung injury. Isolated-perfused lungs were inflated with continuous positive airway pressures of 5 or 15 cm H2O (n = 7 each), and endothelial calcium concentration was quantified by real-time imaging. RESULTS Genetic deficiency or pharmacologic inhibition of TRPV4 or SGK1 protected mice from overventilation-induced vascular leakage (reduction in alveolar protein concentration from 0.84 ± 0.18 [mean ± SD] to 0.46 ± 0.16 mg/ml by TRPV4 antagonization), reduced lung inflammation (macrophage inflammatory protein 2 levels of 193 ± 163 in Trpv4 vs. 544 ± 358 pmol/ml in wild-type mice), and attenuated endothelial calcium responses to lung overdistension. Functional coupling of TRPV4 and SGK1 in lung endothelial mechanotransduction was confirmed by proximity ligation assay demonstrating enhanced TRPV4 phosphorylation at serine 824 at 18% as compared to 5% cyclic stretch, which was prevented by SGK1 inhibition. CONCLUSIONS Lung overventilation promotes endothelial calcium influx and barrier failure through a mechanism that involves activation of TRPV4, presumably due to phosphorylation at its serine 824 residue by SGK1. TRPV4 and SGK1 may present promising new targets for prevention or treatment of ventilator-induced lung injury.
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32
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Fujita T, Higashitsuji H, Higashitsuji H, Liu Y, Itoh K, Sakurai T, Kojima T, Kandori S, Nishiyama H, Fukumoto M, Fukumoto M, Shibasaki K, Fujita J. TRPV4-dependent induction of a novel mammalian cold-inducible protein SRSF5 as well as CIRP and RBM3. Sci Rep 2017; 7:2295. [PMID: 28536481 PMCID: PMC5442135 DOI: 10.1038/s41598-017-02473-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 04/11/2017] [Indexed: 02/06/2023] Open
Abstract
Cold-inducible RNA-binding protein (CIRP) and RNA-binding motif protein 3 (RBM3) are two evolutionarily conserved RNA-binding proteins that are structurally related to hnRNPs and upregulated in response to moderately low temperatures in mammalian cells. Although contributions of splicing efficiency, the gene promoters activated upon mild hypothermia and the transcription factor Sp1 to induction of CIRP have been reported, precise mechanisms by which hypothermia and other stresses induce the expression of mammalian cold-inducible proteins (CIPs) are poorly understood. By screening the serine/arginine-rich splicing factors (SRSFs), we report that the transcript and protein levels of SRSF5 were increased in mammalian cells cultured at 32 °C. Expression of SRSF5 as well as CIRP and RBM3 were also induced by DNA damage, hypoxia, cycloheximide and hypotonicity. Immunohistochemical studies demonstrated that SRSF5 was constitutively expressed in male germ cells and the level was decreased in human testicular germ cell tumors. SRSF5 facilitated production of p19 H-RAS, and increased sensitivity to doxorubicin in human U-2 OS cells. Induction of CIPs was dependent on transient receptor potential vanilloid 4 (TRPV4) channel protein, but seemed independent of its ion channel activity. These findings indicate a previously unappreciated role for the TRP protein in linking environmental stress to splicing.
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Affiliation(s)
- Takanori Fujita
- Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, 606-8507, Japan.,School of Economics, Nagoya University, Nagoya, Nagoya, 464-8601, Japan
| | - Hiroaki Higashitsuji
- Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, 606-8507, Japan
| | - Hisako Higashitsuji
- Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, 606-8507, Japan
| | - Yu Liu
- Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, 606-8507, Japan
| | - Katsuhiko Itoh
- Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, 606-8507, Japan
| | - Toshiharu Sakurai
- Department of Gastroenterology and Hepatology, Kindai University Faculty of Medicine, Osaka-Sayama, Osaka, 589-8511, Japan
| | - Takahiro Kojima
- Department of Urology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, 305-8575, Japan
| | - Shuya Kandori
- Department of Urology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, 305-8575, Japan
| | - Hiroyuki Nishiyama
- Department of Urology, Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, 305-8575, Japan
| | - Motoi Fukumoto
- Department of Pathology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, 980-8575, Japan
| | - Manabu Fukumoto
- Department of Pathology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, 980-8575, Japan.,Department of Molecular Pathology, Tokyo Medical University, Shinjuku-ku, Tokyo, 160-8402, Japan
| | - Koji Shibasaki
- Department of Molecular and Cellular Neurobiology, Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan
| | - Jun Fujita
- Department of Clinical Molecular Biology, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto, 606-8507, Japan. .,Department of Rehabilitation Medicine, Biwako-Chuo Hospital, Otsu, Shiga, 520-0834, Japan.
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33
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White JPM, Cibelli M, Urban L, Nilius B, McGeown JG, Nagy I. TRPV4: Molecular Conductor of a Diverse Orchestra. Physiol Rev 2017; 96:911-73. [PMID: 27252279 DOI: 10.1152/physrev.00016.2015] [Citation(s) in RCA: 261] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Transient receptor potential vanilloid type 4 (TRPV4) is a calcium-permeable nonselective cation channel, originally described in 2000 by research teams led by Schultz (Nat Cell Biol 2: 695-702, 2000) and Liedtke (Cell 103: 525-535, 2000). TRPV4 is now recognized as being a polymodal ionotropic receptor that is activated by a disparate array of stimuli, ranging from hypotonicity to heat and acidic pH. Importantly, this ion channel is constitutively expressed and capable of spontaneous activity in the absence of agonist stimulation, which suggests that it serves important physiological functions, as does its widespread dissemination throughout the body and its capacity to interact with other proteins. Not surprisingly, therefore, it has emerged more recently that TRPV4 fulfills a great number of important physiological roles and that various disease states are attributable to the absence, or abnormal functioning, of this ion channel. Here, we review the known characteristics of this ion channel's structure, localization and function, including its activators, and examine its functional importance in health and disease.
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Affiliation(s)
- John P M White
- Anaesthetics, Pain Medicine and Intensive Care Section, Department of Surgery and Cancer, Imperial College London, London, United Kingdom; Department of Anaesthetics, The Queen Elizabeth Hospital, Birmingham, United Kingdom; Academic Department of Anaesthesia and Intensive Care Medicine, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom; Preclinical Secondary Pharmacology, Preclinical Safety, Novartis Institute for Biomedical Research, Cambridge, Massachusetts; Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg, Leuven, Belgium; and School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Belfast, United Kingdom
| | - Mario Cibelli
- Anaesthetics, Pain Medicine and Intensive Care Section, Department of Surgery and Cancer, Imperial College London, London, United Kingdom; Department of Anaesthetics, The Queen Elizabeth Hospital, Birmingham, United Kingdom; Academic Department of Anaesthesia and Intensive Care Medicine, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom; Preclinical Secondary Pharmacology, Preclinical Safety, Novartis Institute for Biomedical Research, Cambridge, Massachusetts; Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg, Leuven, Belgium; and School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Belfast, United Kingdom
| | - Laszlo Urban
- Anaesthetics, Pain Medicine and Intensive Care Section, Department of Surgery and Cancer, Imperial College London, London, United Kingdom; Department of Anaesthetics, The Queen Elizabeth Hospital, Birmingham, United Kingdom; Academic Department of Anaesthesia and Intensive Care Medicine, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom; Preclinical Secondary Pharmacology, Preclinical Safety, Novartis Institute for Biomedical Research, Cambridge, Massachusetts; Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg, Leuven, Belgium; and School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Belfast, United Kingdom
| | - Bernd Nilius
- Anaesthetics, Pain Medicine and Intensive Care Section, Department of Surgery and Cancer, Imperial College London, London, United Kingdom; Department of Anaesthetics, The Queen Elizabeth Hospital, Birmingham, United Kingdom; Academic Department of Anaesthesia and Intensive Care Medicine, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom; Preclinical Secondary Pharmacology, Preclinical Safety, Novartis Institute for Biomedical Research, Cambridge, Massachusetts; Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg, Leuven, Belgium; and School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Belfast, United Kingdom
| | - J Graham McGeown
- Anaesthetics, Pain Medicine and Intensive Care Section, Department of Surgery and Cancer, Imperial College London, London, United Kingdom; Department of Anaesthetics, The Queen Elizabeth Hospital, Birmingham, United Kingdom; Academic Department of Anaesthesia and Intensive Care Medicine, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom; Preclinical Secondary Pharmacology, Preclinical Safety, Novartis Institute for Biomedical Research, Cambridge, Massachusetts; Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg, Leuven, Belgium; and School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Belfast, United Kingdom
| | - Istvan Nagy
- Anaesthetics, Pain Medicine and Intensive Care Section, Department of Surgery and Cancer, Imperial College London, London, United Kingdom; Department of Anaesthetics, The Queen Elizabeth Hospital, Birmingham, United Kingdom; Academic Department of Anaesthesia and Intensive Care Medicine, School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, United Kingdom; Preclinical Secondary Pharmacology, Preclinical Safety, Novartis Institute for Biomedical Research, Cambridge, Massachusetts; Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, Campus Gasthuisberg, Leuven, Belgium; and School of Medicine, Dentistry and Biomedical Science, Queen's University Belfast, Belfast, United Kingdom
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34
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Brown CL, Fleischauer V, Heo J. High-throughput Screening of Erratic Cell Volume Regulation Using a Hydrogel-based Single-cell Microwell Array. ANAL SCI 2017; 33:525-530. [PMID: 28392532 DOI: 10.2116/analsci.33.525] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Here, we report that a single-cell microwell array based on photocrosslinked hydrogel can be used to screen cells exhibiting a defective regulatory volume decrease (RVD) in high-throughput. The RVD is a regulatory function of cells that maintains cell volume homeostasis in a hypotonic medium. Single Madin-Darby canine kidney (MDCK) cells grown in the microwells were loaded with a volume-sensitive fluorescence dye. Changes in the volume of discrete single cells were traced for 20 min in a hypotonic solution using a wide-field fluorescence microscopy. The volume changes of more than 100 single cells were analyzed simultaneously using time-lapse fluorescence micrographs. Cells showing erratic RVD could be easily screened from the image analysis. Nearly 40% of the MDCK single cells exhibited weak, or no, RVD. Since other previously reported methods could not detect as many changes in the volume of discrete singles cells as the method used in this report, we anticipate that our reported method will provide an efficient way of elucidating the RVD mechanisms of cells that have not yet been completely understood.
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35
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Hypotonic stress promotes ATP release, reactive oxygen species production and cell proliferation via TRPV4 activation in rheumatoid arthritis rat synovial fibroblasts. Biochem Biophys Res Commun 2017; 486:108-115. [PMID: 28274876 DOI: 10.1016/j.bbrc.2017.03.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 03/03/2017] [Indexed: 12/31/2022]
Abstract
Rheumatoid arthritis (RA) is a chronic and systemic autoimmune-disease with complex and unclear etiology. Hypotonicity of synovial fluid is a typical characteristic of RA, which may play pivotal roles in RA pathogenesis. In this work, we studied the responses of RA synovial fibroblasts to hypotonic stress in vitro and further explored the underlying mechanisms. Data showed that hyposmotic solutions significantly triggered increases in cytosolic calcium concentration ([Ca2+]c) of synoviocytes. Subsequently, it caused rapid release of ATP, as well as remarkable production of intracellular reactive oxygen species (ROS). Meanwhile, hypotonic stimulus promoted the proliferation of synovial fibroblasts. These effects were almost abolished by calcium-free buffer and significantly inhibited by gadolinium (III) chloride (a mechanosensitive Ca2+ channel blocker) and ruthenium red (a transient receptor potential vanilloid 4 (TRPV4) blocker). 4α-phorbol 12,13-didecanoate, a specific agonist of TRPV4, also mimicked hypotonic shock-induced responses shown above. In contrast, voltage-gated channel inhibitors verapamil and nifedipine had little influences on these responses. Furthermore, RT-PCR and western blotting evidently detected TRPV4 expression at mRNA and protein level in isolated synoviocytes. Taken together, our results indicated that hypotonic stimulus resulted in ATP release, ROS production, and cell proliferation depending on Ca2+ entry through activation of TRPV4 channel in synoviocytes.
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36
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The renal TRPV4 channel is essential for adaptation to increased dietary potassium. Kidney Int 2017; 91:1398-1409. [PMID: 28187982 DOI: 10.1016/j.kint.2016.12.010] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/22/2016] [Accepted: 12/08/2016] [Indexed: 12/11/2022]
Abstract
To maintain potassium homeostasis, kidneys exert flow-dependent potassium secretion to facilitate kaliuresis in response to elevated dietary potassium intake. This process involves stimulation of calcium-activated large conductance maxi-K (BK) channels in the distal nephron, namely the connecting tubule and the collecting duct. Recent evidence suggests that the TRPV4 channel is a critical determinant of flow-dependent intracellular calcium elevations in these segments of the renal tubule. Here, we demonstrate that elevated dietary potassium intake (five percent potassium) increases renal TRPV4 mRNA and protein levels in an aldosterone-dependent manner and causes redistribution of the channel to the apical plasma membrane in native collecting duct cells. This, in turn, leads to augmented TRPV4-mediated flow-dependent calcium ion responses in freshly isolated split-opened collecting ducts from mice fed the high potassium diet. Genetic TRPV4 ablation greatly diminished BK channel activity in collecting duct cells pointing to a reduced capacity to excrete potassium. Consistently, elevated potassium intake induced hyperkalemia in TRPV4 knockout mice due to deficient renal potassium excretion. Thus, regulation of TRPV4 activity in the distal nephron by dietary potassium is an indispensable component of whole body potassium balance.
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37
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Siroky BJ, Kleene NK, Kleene SJ, Varnell CD, Comer RG, Liu J, Lu L, Pachciarz NW, Bissler JJ, Dixon BP. Primary cilia regulate the osmotic stress response of renal epithelial cells through TRPM3. Am J Physiol Renal Physiol 2017; 312:F791-F805. [PMID: 28122715 PMCID: PMC5407065 DOI: 10.1152/ajprenal.00465.2015] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 01/10/2017] [Accepted: 01/18/2017] [Indexed: 12/26/2022] Open
Abstract
Primary cilia sense environmental conditions, including osmolality, but whether cilia participate in the osmotic response in renal epithelial cells is not known. The transient receptor potential (TRP) channels TRPV4 and TRPM3 are osmoresponsive. TRPV4 localizes to cilia in certain cell types, while renal subcellular localization of TRPM3 is not known. We hypothesized that primary cilia are required for maximal activation of the osmotic response of renal epithelial cells and that ciliary TRPM3 and TRPV4 mediate that response. Ciliated [murine epithelial cells from the renal inner medullary collecting duct (mIMCD-3) and 176-5] and nonciliated (176-5Δ) renal cells expressed Trpv4 and Trpm3 Ciliary expression of TRPM3 was observed in mIMCD-3 and 176-5 cells and in wild-type mouse kidney tissue. TRPV4 was identified in cilia and apical membrane of mIMCD-3 cells by electrophysiology and in the cell body by immunofluorescence. Hyperosmolal stress at 500 mOsm/kg (via NaCl addition) induced the osmotic response genes betaine/GABA transporter (Bgt1) and aldose reductase (Akr1b3) in all ciliated cell lines. This induction was attenuated in nonciliated cells. A TRPV4 agonist abrogated Bgt1 and Akr1b3 induction in ciliated and nonciliated cells. A TRPM3 agonist attenuated Bgt1 and Akr1b3 induction in ciliated cells only. TRPM3 knockout attenuated Akr1b3 induction. Viability under osmotic stress was greater in ciliated than nonciliated cells. Akr1b3 induction was also less in nonciliated than ciliated cells when mannitol was used to induce hyperosmolal stress. These findings suggest that primary cilia are required for the maximal osmotic response in renal epithelial cells and that TRPM3 is involved in this mechanism. TRPV4 appears to modulate the osmotic response independent of cilia.
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Affiliation(s)
- Brian J Siroky
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Nancy K Kleene
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio; and
| | - Steven J Kleene
- Department of Molecular and Cellular Physiology, University of Cincinnati, Cincinnati, Ohio; and
| | - Charles D Varnell
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Raven G Comer
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Jialiu Liu
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Lu Lu
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Nolan W Pachciarz
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - John J Bissler
- St. Jude Children's Research Hospital and Le Bonheur Children's Hospital, University of Tennessee Health Science Center, Memphis, Tennessee
| | - Bradley P Dixon
- Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio;
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Ying L, Becard M, Lyell D, Han X, Shortliffe L, Husted CI, Alvira CM, Cornfield DN. The transient receptor potential vanilloid 4 channel modulates uterine tone during pregnancy. Sci Transl Med 2017; 7:319ra204. [PMID: 26702092 DOI: 10.1126/scitranslmed.aad0376] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The importance of gaining insight into the mechanisms underlying uterine quiescence and contractility is highlighted by the absence of an effective strategy to prevent or treat preterm labor, the greatest cause of perinatal mortality and morbidity worldwide. Although current evidence suggests that in myometrial smooth muscle cells (mSMCs) calcium homeostasis is modulated near term to promote uterine contractility, the efficacy of blocking voltage-operated calcium channels is limited by dose-related cardiovascular side effects. Thus, we considered whether uterine contractility might be modulated by calcium entry via transient receptor potential vanilloid 4 (TRPV4) channels. In mSMC, TRPV4 gene and protein expression increased with gestation, and TRPV4-mediated Ca(2+) entry and contractility were increased in mSMC from pregnant compared to nonpregnant rats. Cell membrane TRPV4 expression was specifically increased, whereas the expression of β-arrestin-1 and β-arrestin-2, molecules that can sequester TRPV4 in the cytoplasm, decreased. Physical interaction of β-arrestin-2 and TRPV4 was apparent in nonpregnant, but absent in pregnant, mouse uterus. Moreover, direct pharmacologic activation of TRPV4 increased uterine contraction, but oxytocin-induced myometrial contraction was blocked by pharmacologic inhibition of TRPV4 and decreased in mice with global deletion of TRPV4. Finally, TRPV4 channel blockade prolonged pregnancy in two distinct in vivo murine models of preterm labor, whereas the absence of either β-arrestin-1 or β-arrestin-2 increased susceptibility to preterm labor. These data suggest that TRPV4 channel activity modulates uterine contractility and might represent a therapeutic target to address preterm labor.
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Affiliation(s)
- Lihua Ying
- Center for Excellence in Pulmonary Biology, Stanford University Medical School, Stanford, CA 94305, USA
| | - Margaux Becard
- Pôle Mère, Département de Gynécologie Obstétrique, Centre Hospitalier de Calais, Calais 62100, France
| | - Deirdre Lyell
- Departments of Pediatrics and Obstetrics and Gynecology, Stanford University Medical School, Stanford, CA 94305, USA
| | - Xiaoyuan Han
- Department of Urology, Stanford University Medical School, Stanford, CA 94305, USA
| | - Linda Shortliffe
- Department of Urology, Stanford University Medical School, Stanford, CA 94305, USA
| | - Cristiana Iosef Husted
- Department of Biochemistry and Molecular Biology, School of Medicine, University of Nevada, Reno, CA 89557, USA
| | - Cristina M Alvira
- Center for Excellence in Pulmonary Biology, Stanford University Medical School, Stanford, CA 94305, USA. Divisions of Pulmonary, Asthma and Sleep Medicine, Stanford University Medical School, Stanford, CA 94305, USA
| | - David N Cornfield
- Center for Excellence in Pulmonary Biology, Stanford University Medical School, Stanford, CA 94305, USA. Divisions of Pulmonary, Asthma and Sleep Medicine, Stanford University Medical School, Stanford, CA 94305, USA. Division of Critical Care Medicine, Stanford University Medical School, Stanford, CA 94305, USA
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40
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Walter B, Purmessur D, Moon A, Occhiogrosso J, Laudier D, Hecht A, Iatridis J. Reduced tissue osmolarity increases TRPV4 expression and pro-inflammatory cytokines in intervertebral disc cells. Eur Cell Mater 2016; 32:123-36. [PMID: 27434269 PMCID: PMC5072776 DOI: 10.22203/ecm.v032a08] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The mechanical behaviour and cellular metabolism of intervertebral discs (IVDs) and articular cartilage are strongly influenced by their proteoglycan content and associated osmotic properties. This osmotic environment is a biophysical signal that changes with disease and may contribute to the elevated matrix breakdown and altered biologic response to loading observed in IVD degeneration and osteoarthritis. This study tested the hypothesis that changes in osmo-sensation by the transient receptor potential vallinoid-4 (TRPV4) ion channel occur with disease and contribute to the inflammatory environment found during degeneration. Immunohistochemistry on bovine IVDs from an inflammatory organ culture model were used to investigate if TRPV4 is expressed in the IVD and how expression changes with degeneration. Western blot, live-cell calcium imaging, and qRT-PCR were used to investigate whether osmolarity changes or tumour necrosis factor α (TNFα) regulate TRPV4 expression, and how altered TRPV4 expression influences calcium signalling and pro-inflammatory cytokine expression. TRPV4 expression correlated with TNFα expression, and was increased when cultured in reduced medium osmolarity and unaltered with TNFα-stimulation. Increased TRPV4 expression increased the calcium flux following TRPV4 activation and increased interleukin-1β (IL-1β) and IL-6 gene expression in IVD cells. TRPV4 expression was qualitatively elevated in regions of aggrecan depletion in degenerated human IVDs. Collectively, results suggest that reduced tissue osmolarity, likely following proteoglycan degradation, can increase TRPV4 signalling and enhance pro-inflammatory cytokine production, suggesting changes in TRPV4 mediated osmo-sensation may contribute to the progressive matrix breakdown in disease.
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Affiliation(s)
- B.A. Walter
- Leni & Peter W. May Department of Orthopaedics at the Icahn School of Medicine at Mount Sinai, New York, NY, USA,Department of Biomedical Engineering, The City College of New York, New York, NY, USA
| | - D Purmessur
- Leni & Peter W. May Department of Orthopaedics at the Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - A. Moon
- Leni & Peter W. May Department of Orthopaedics at the Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J. Occhiogrosso
- Leni & Peter W. May Department of Orthopaedics at the Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - D.M. Laudier
- Leni & Peter W. May Department of Orthopaedics at the Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - A.C. Hecht
- Leni & Peter W. May Department of Orthopaedics at the Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J.C. Iatridis
- Leni & Peter W. May Department of Orthopaedics at the Icahn School of Medicine at Mount Sinai, New York, NY, USA,Address for correspondence: James C. Iatridis Leni & Peter W. May Department of Orthopaedics, Box 1188, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA, Telephone Number: 1-212-241-1517, FAX Number: 1-212-876-3168 www.ecmjournal.org
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TRPV4 is associated with central rather than nephrogenic osmoregulation. Pflugers Arch 2016; 468:1595-607. [PMID: 27364478 DOI: 10.1007/s00424-016-1850-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/07/2016] [Accepted: 06/09/2016] [Indexed: 12/28/2022]
Abstract
TRPV4 is a polymodal cation channel expressed in osmosensitive neurons of the hypothalamus and in the mammalian nephron. The segmental distribution and role(s) of TRPV4 in osmoregulation remain debated. We investigated the renal distribution pattern of TRPV4 and the functional consequences of its disruption in mouse models. Using qPCR on microdissected segments, immunohistochemistry, and a LacZ reporter mouse, we found that TRPV4 is abundantly expressed in the proximal tubule, the late distal convoluted tubule, and throughout the connecting tubule and collecting duct, including principal and intercalated cells. TRPV4 was undetectable in the glomeruli and thick ascending limb and weakly abundant in the early distal convoluted tubule. Metabolic studies in Trpv4 (+/+) and Trpv4 (-/-) littermates revealed that the lack of TRPV4 did not influence activity, food and water intake, renal function, and urinary concentration at baseline. The mice showed a similar response to furosemide, water loading and deprivation, acid loading, and dietary NaCl restriction. However, Trpv4 (-/-) mice showed a significantly lower vasopressin synthesis and release after water deprivation, with a loss of the positive correlation between plasma osmolality and plasma vasopressin levels, and a delayed water intake upon acute administration of hypertonic saline. Specific activation of TRPV4 in primary cultures of proximal tubule cells increased albumin uptake, whereas no effect of TRPV4 deletion could be observed at baseline. These data reveal that, despite its abundant expression in tubular segments, TRPV4 does not play a major role in the kidney or is efficiently compensated when deleted. Instead, TRPV4 is critical for the release of vasopressin, the sensation of thirst, and the central osmoregulation.
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Expression of a Diverse Array of Ca2+-Activated K+ Channels (SK1/3, IK1, BK) that Functionally Couple to the Mechanosensitive TRPV4 Channel in the Collecting Duct System of Kidney. PLoS One 2016; 11:e0155006. [PMID: 27159616 PMCID: PMC4861333 DOI: 10.1371/journal.pone.0155006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 04/22/2016] [Indexed: 12/02/2022] Open
Abstract
The voltage- and Ca2+-activated, large conductance K+ channel (BK, maxi-K) is expressed in the collecting duct system of kidney where it underlies flow- and Ca2+-dependent K+ excretion. To determine if other Ca2+-activated K+ channels (KCa) may participate in this process, mouse kidney and the K+-secreting mouse cortical collecting duct (CCD) cell line, mCCDcl1, were assessed for TRPV4 and KCa channel expression and cross-talk. qPCR mRNA analysis and immunocytochemical staining demonstrated TRPV4 and KCa expression in mCCDcl1 cells and kidney connecting tubule (CNT) and CCD. Three subfamilies of KCa channels were revealed: the high Ca2+-binding affinity small-conductance SK channels, SK1and SK3, the intermediate conductance channel, IK1, and the low Ca2+-binding affinity, BK channel (BKα subunit). Apparent expression levels varied in CNT/CCD where analysis of CCD principal cells (PC) and intercalated cells (IC) demonstrated differential staining: SK1:PC<IC, and SK3:PC>IC, IK1:PC>IC, BKα:PC = IC, and TRPV4:PC>IC. Patch clamp analysis and fluorescence Ca2+ imaging of mCCDcl1 cells demonstrated potent TRPV4-mediated Ca2+ entry and strong functional cross-talk between TRPV4 and KCa channels. TRPV4-mediated Ca2+ influx activated each KCa channel, as evidenced by selective inhibition of KCa channels, with each active KCa channel enhancing Ca2+ entry (due to membrane hyperpolarization). Transepithelial electrical resistance (TEER) analysis of confluent mCCDcl1 cells grown on permeable supports further demonstrated this cross-talk where TRPV4 activation induce a decrease in TEER which was partially restored upon selective inhibition of each KCa channel. It is concluded that SK1/SK3 and IK1 are highly expressed along with BKα in CNT and CCD and are closely coupled to TRPV4 activation as observed in mCCDcl1 cells. The data support a model in CNT/CCD segments where strong cross talk between TRPV4-mediated Ca2+ influx and each KCa channel leads to enhance Ca2+ entry which will support activation of the low Ca2+-binding affinity BK channel to promote BK-mediated K+ secretion.
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Du J, Wang X, Li J, Guo J, Liu L, Yan D, Yang Y, Li Z, Zhu J, Shen B. Increasing TRPV4 expression restores flow-induced dilation impaired in mesenteric arteries with aging. Sci Rep 2016; 6:22780. [PMID: 26947561 PMCID: PMC4780030 DOI: 10.1038/srep22780] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 02/23/2016] [Indexed: 12/30/2022] Open
Abstract
The flow-stimulated intracellular Ca2+ concentration ([Ca2+]i) rise in endothelial cells is an important early event leading to flow-induced blood vessel dilation. Transient receptor potential vanilloid subtype 4 (TRPV4), a Ca2+-permeable cation channel, facilitates the flow-stimulated [Ca2+]i rise. To determine whether TRPV4 is involved in age-related flow-induced blood vessel dilation impairment, we measured blood vessel diameter and nitric oxide (NO) levels and performed Ca2+ imaging, immunoblotting, and immunostaining assays in rats. We found that the flow-induced and TRPV4 activator 4α-PDD-induced dilation of mesenteric arteries from aged rats were significantly decreased compared with those from young rats. The flow- or 4α-PDD-induced [Ca2+]i rise was also markedly reduced in primary cultured mesenteric artery endothelial cells (MAECs) from aged rats. Immunoblotting and immunostaining results showed an age-related decrease of TRPV4 expression levels in MAECs. Additionally, the 4α-PDD-induced NO production was significantly reduced in aged MAECs. Compared with lentiviral GFP-treated aged rats, lentiviral vector delivery of TRPV4 increased TRPV4 expression level in aged MAECs and restored the flow- and 4α-PDD-induced vessel dilation in aged mesenteric arteries. We concluded that impaired TRPV4-mediated Ca2+ signaling causes endothelial dysfunction and that TRPV4 is a potential target for clinical treatment of age-related vascular system diseases.
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Affiliation(s)
- Juan Du
- Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, China
| | - Xia Wang
- Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, China
| | - Jie Li
- Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, China
| | - Jizheng Guo
- Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, China
| | - Limei Liu
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Peking 100191, China
| | - Dejun Yan
- Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, China
| | - Yunyun Yang
- Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, China
| | - Zhongwen Li
- Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, China
| | - Jinhang Zhu
- Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, China
| | - Bing Shen
- Department of Physiology, School of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, China.,Central laboratory of molecular and cellular biology of School of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, China
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Reinach PS, Mergler S, Okada Y, Saika S. Ocular transient receptor potential channel function in health and disease. BMC Ophthalmol 2015; 15 Suppl 1:153. [PMID: 26818117 PMCID: PMC4895786 DOI: 10.1186/s12886-015-0135-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Transient receptor potential (TRP) channels sense and transduce environmental stimuli into Ca(2+) transients that in turn induce responses essential for cell function and adaptation. These non-selective channels with variable Ca(2+) selectivity are grouped into seven different subfamilies containing 28 subtypes based on differences in amino acid sequence homology. Many of these subtypes are expressed in the eye on both neuronal and non-neuronal cells where they affect a host of stress-induced regulatory responses essential for normal vision maintenance. This article reviews our current knowledge about the expression, function and regulation of TRPs in different eye tissues. We also describe how under certain conditions TRP activation can induce responses that are maladaptive to ocular function. Furthermore, the possibility of an association between TRP mutations and disease is considered. These findings contribute to evidence suggesting that drug targeting TRP channels may be of therapeutic benefit in a clinical setting. We point out issues that must be more extensively addressed before it will be possible to decide with certainty that this is a realistic endeavor. Another possible upshot of future studies is that disease process progression can be better evaluated by profiling changes in tissue specific functional TRP subtype activity as well as their gene and protein expression.
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Affiliation(s)
- Peter S Reinach
- Department of Ophthalmology and Optometry, Wenzhou Medical University, 270 Xuejuan Road, Wenzhou, Zhejiang, 325027, P. R. China.
| | - Stefan Mergler
- Department of Ophthalmology, Charité-University Medicine Berlin, Campus Virchow-Clinic, Augustenburger Platz 1, 13353, Berlin, Germany.
| | - Yuka Okada
- Department of Ophthalmology, Wakayama Medical University School of Medicine, Wakayama, Japan.
| | - Shizuya Saika
- Department of Ophthalmology, Wakayama Medical University School of Medicine, Wakayama, Japan.
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Carrisoza-Gaytan R, Carattino MD, Kleyman TR, Satlin LM. An unexpected journey: conceptual evolution of mechanoregulated potassium transport in the distal nephron. Am J Physiol Cell Physiol 2015; 310:C243-59. [PMID: 26632600 DOI: 10.1152/ajpcell.00328.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Flow-induced K secretion (FIKS) in the aldosterone-sensitive distal nephron (ASDN) is mediated by large-conductance, Ca(2+)/stretch-activated BK channels composed of pore-forming α-subunits (BKα) and accessory β-subunits. This channel also plays a critical role in the renal adaptation to dietary K loading. Within the ASDN, the cortical collecting duct (CCD) is a major site for the final renal regulation of K homeostasis. Principal cells in the ASDN possess a single apical cilium whereas the surfaces of adjacent intercalated cells, devoid of cilia, are decorated with abundant microvilli and microplicae. Increases in tubular (urinary) flow rate, induced by volume expansion, diuretics, or a high K diet, subject CCD cells to hydrodynamic forces (fluid shear stress, circumferential stretch, and drag/torque on apical cilia and presumably microvilli/microplicae) that are transduced into increases in principal (PC) and intercalated (IC) cell cytoplasmic Ca(2+) concentration that activate apical voltage-, stretch- and Ca(2+)-activated BK channels, which mediate FIKS. This review summarizes studies by ourselves and others that have led to the evolving picture that the BK channel is localized in a macromolecular complex at the apical membrane, composed of mechanosensitive apical Ca(2+) channels and a variety of kinases/phosphatases as well as other signaling molecules anchored to the cytoskeleton, and that an increase in tubular fluid flow rate leads to IC- and PC-specific responses determined, in large part, by the cell-specific composition of the BK channels.
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Affiliation(s)
| | - Marcelo D Carattino
- Renal-Electrolyte Division, Department of Medicine, Pittsburgh, Pennsylvania
| | - Thomas R Kleyman
- Renal-Electrolyte Division, Department of Medicine, Pittsburgh, Pennsylvania
| | - Lisa M Satlin
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York; and
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Ikari A, Fujii N, Hahakabe S, Hayashi H, Yamaguchi M, Yamazaki Y, Endo S, Matsunaga T, Sugatani J. Hyperosmolarity-Induced Down-Regulation of Claudin-2 Mediated by Decrease in PKCβ-Dependent GATA-2 in MDCK Cells. J Cell Physiol 2015; 230:2776-87. [PMID: 25825272 DOI: 10.1002/jcp.25004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 03/25/2015] [Indexed: 01/20/2023]
Abstract
Hyperosmolarity decreases claudin-2 expression in renal tubular epithelial cells, but the molecular mechanism remains undefined. Here, we found that the hyperosmolarity-induced decrease in claudin-2 expression is inhibited by Go6983, a non-selective protein kinase C (PKC) inhibitor, and PKCβ specific inhibitor in Madin-Darby canine kidney II cells. Hyperosmolarity increased intracellular free Ca(2+) concentration and phosphorylated PKCβ level, which were inhibited by RN-1734, an antagonist of transient receptor potential vanilloid 4 channel. Phorbol 12-myristate 13-acetate, a PKC activator, decreased claudin-2 expression. These results indicate hyperosmolarity decreases claudin-2 expression mediated by the activation of RN-1734-sensitive channel and PKCβ. Hyperosmolarity decreased promoter activity of claudin-2, which was inhibited by Go6983 and PKCβ inhibitor similar to those in real-time PCR and Western blotting. The effect of hyperosmolarity on promoter activity was not observed in the construct of -469/-6, a deletion mutant. Claudin-2 has hyperosmolarity-sensitive region in its promoter, which includes GATA binding site. Hyperosmolarity decreased the nuclear level of GATA-2, which was inhibited by Go6983 and PKCβ inhibitor. Mutation of GATA binding site decreased the basal promoter activity and inhibited the effect of hyperosmolarity. In contrast, the hyperosmolarity-induced decrease in reporter activity and claudin-2 expression were rescued by over-expression of wild type GATA-2. Chromatin immunoprecipitation assay showed that GATA-2 bound to promoter region of claudin-2. These results suggest that hyperosmolarity decreases the expression level of claudin-2 via a decrease in PKCβ-dependent GATA-2 transcriptional activity in renal tubular epithelial cells.
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Affiliation(s)
- Akira Ikari
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, Japan
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Naoko Fujii
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, Japan
| | - Shinya Hahakabe
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Hisayoshi Hayashi
- School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Masahiko Yamaguchi
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yasuhiro Yamazaki
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Satoshi Endo
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, Japan
| | - Toshiyuki Matsunaga
- Laboratory of Biochemistry, Department of Biopharmaceutical Sciences, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu, Japan
| | - Junko Sugatani
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
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ATP release, generation and hydrolysis in exocrine pancreatic duct cells. Purinergic Signal 2015; 11:533-50. [PMID: 26431833 DOI: 10.1007/s11302-015-9472-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 09/14/2015] [Indexed: 12/24/2022] Open
Abstract
Extracellular adenosine triphosphate (ATP) regulates pancreatic duct function via P2Y and P2X receptors. It is well known that ATP is released from upstream pancreatic acinar cells. The ATP homeostasis in pancreatic ducts, which secrete bicarbonate-rich fluid, has not yet been examined. First, our aim was to reveal whether pancreatic duct cells release ATP locally and whether they enzymatically modify extracellular nucleotides/sides. Second, we wished to explore which physiological and pathophysiological factors may be important in these processes. Using a human pancreatic duct cell line, Capan-1, and online luminescence measurement, we detected fast ATP release in response to pH changes, bile acid, mechanical stress and hypo-osmotic stress. ATP release following hypo-osmotic stress was sensitive to drugs affecting exocytosis, pannexin-1, connexins, maxi-anion channels and transient receptor potential cation channel subfamily V member 4 (TRPV4) channels, and corresponding transcripts were expressed in duct cells. Direct stimulation of intracellular Ca(2+) and cAMP signalling and ethanol application had negligible effects on ATP release. The released ATP was sequentially dephosphorylated through ecto-nucleoside triphosphate diphosphohydrolase (NTPDase2) and ecto-5'-nucleotidase/CD73 reactions, with respective generation of adenosine diphosphate (ADP) and adenosine and their maintenance in the extracellular medium at basal levels. In addition, Capan-1 cells express counteracting adenylate kinase (AK1) and nucleoside diphosphate kinase (NDPK) enzymes (NME1, 2), which contribute to metabolism and regeneration of extracellular ATP and other nucleotides (ADP, uridine diphosphate (UDP) and uridine triphosphate (UTP)). In conclusion, we illustrate a complex regulation of extracellular purine homeostasis in a pancreatic duct cell model involving: ATP release by several mechanisms and subsequent nucleotide breakdown and ATP regeneration via counteracting nucleotide-inactivating and nucleotide-phosphorylating ecto-enzymes. We suggest that extracellular ATP homeostasis in pancreatic ducts may be important in pancreas physiology and potentially in pancreas pathophysiology.
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Tomilin V, Mamenko M, Zaika O, Pochynyuk O. Role of renal TRP channels in physiology and pathology. Semin Immunopathol 2015; 38:371-83. [PMID: 26385481 DOI: 10.1007/s00281-015-0527-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 09/04/2015] [Indexed: 01/05/2023]
Abstract
Kidneys critically contribute to the maintenance of whole-body homeostasis by governing water and electrolyte balance, controlling extracellular fluid volume, plasma osmolality, and blood pressure. Renal function is regulated by numerous systemic endocrine and local mechanical stimuli. Kidneys possess a complex network of membrane receptors, transporters, and ion channels which allows responding to this wide array of signaling inputs in an integrative manner. Transient receptor potential (TRP) channel family members with diverse modes of activation, varied permeation properties, and capability to integrate multiple downstream signals are pivotal molecular determinants of renal function all along the nephron. This review summarizes experimental data on the role of TRP channels in a healthy mammalian kidney and discusses their involvement in renal pathologies.
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Affiliation(s)
- Viktor Tomilin
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA.,Institute of Cytology, Russian Academy of Sciences, St. Petersburg, Russian Federation
| | - Mykola Mamenko
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA
| | - Oleg Zaika
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA
| | - Oleh Pochynyuk
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, 6431 Fannin, Houston, TX, 77030, USA.
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Cabral PD, Capurro C, Garvin JL. TRPV4 mediates flow-induced increases in intracellular Ca in medullary thick ascending limbs. Acta Physiol (Oxf) 2015; 214:319-28. [PMID: 25980432 DOI: 10.1111/apha.12528] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 01/08/2015] [Accepted: 05/12/2015] [Indexed: 11/28/2022]
Abstract
UNLABELLED Medullary thick ascending limbs (mTAL) regulate Na balance and therefore blood pressure. We previously showed that cell swelling and luminal flow activates the mechanosensitive channel TRPV4 in mTAL. AIM We hypothesized that TRPV4 mediates flow-induced increases in intracellular Ca (Cai) in rat mTALs. METHODS We performed ratiometric measurements of Cai in perfused mTALs. RESULTS Increasing luminal flow from 0 to 20 nL min(-1) caused Cai to peak 231 ± 29 nmol L(-1) above basal concentrations (n = 18). The general TRPV inhibitor ruthenium red at 15 and 50 μmol L(-1) reduced peak Cai by 41 ± 9 (P < 0.01; n = 5) and 77 ± 10% (P < 0.02; n = 6). The selective TRPV4 inhibitor RN1734 at 10 and 50 μmol L(-1) reduced peak Cai by 46 ± 11 (P < 0.01; n = 7) and 76 ± 5% (P < 0.02; n = 5) respectively. To specifically target TRPV4, mTALs were transduced with adenoviruses expressing TRPV4 small hairpin (sh) RNA. In non-transduced control mTALs, luminal flow generated a peak increase in Cai of 111 ± 21 nmol L(-1) (n = 8). In TRPV4shRNA-transduced mTALs, the Cai peak was reduced to 56 ± 8 nmol L(-1) (P < 0.03, n = 9). Removing extracellular Ca completely abolished flow-induced increases in Cai. Increasing luminal flow in the presence of hexokinase 20 (U mL(-1) ) to scavenge extracellular ATP did not modify significantly the increases in Cai induced by luminal flow. Finally, we studied the effect of the TRPV4 selective agonist GSK1016790A on Cai. In the absence of luminal flow, GSK1016790A (10 nmol L(-1) ) increased Cai from 60 ± 11 nmol L(-1) to 262 ± 71 nmol L(-1) (P < 0.05; n = 7). CONCLUSION We conclude that flow-induced increases in Cai are mediated primarily by TRPV4 in the rat mTAL.
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Affiliation(s)
- P. D. Cabral
- Department of Physiology and Biophysics; Case Western Reserve University; Cleveland OH USA
- Facultad de Medicina; IFIBIO-HOUSSAY; UBA-CONICET; Departamento de Ciencias Fisiológicas; Ciudad Autónoma de Buenos Aires; Universidad de Buenos Aires; Buenos Aires Argentina
| | - C. Capurro
- Facultad de Medicina; IFIBIO-HOUSSAY; UBA-CONICET; Departamento de Ciencias Fisiológicas; Ciudad Autónoma de Buenos Aires; Universidad de Buenos Aires; Buenos Aires Argentina
| | - J. L. Garvin
- Department of Physiology and Biophysics; Case Western Reserve University; Cleveland OH USA
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Saifeddine M, El-Daly M, Mihara K, Bunnett NW, McIntyre P, Altier C, Hollenberg MD, Ramachandran R. GPCR-mediated EGF receptor transactivation regulates TRPV4 action in the vasculature. Br J Pharmacol 2015; 172:2493-506. [PMID: 25572823 DOI: 10.1111/bph.13072] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 11/18/2014] [Accepted: 12/28/2014] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Transient receptor potential vanilloid-4 (TRPV4) is a calcium-permeant ion channel that is known to affect vascular function. The ability of TRPV4 to cause a vasoconstriction in blood vessels has not yet been mechanistically examined. Further in neuronal cells, TRPV4 signalling can be potentiated by GPCR activation. Thus, we studied the mechanisms underlying the vascular contractile action of TRPV4 and the GPCR-mediated potentiation of such vasoconstriction, both of which are as yet unappreciated aspects of TRPV4 function. EXPERIMENTAL APPROACH The mechanisms of TRPV4-dependent regulation of vascular tone in isolated mouse aortae were studied using wire myography. TRPV4-dependent calcium signalling and prostanoid production was studied in cultured human umbilical vein endothelial cells (HUVECs). KEY RESULTS In addition to the well-documented vasorelaxation response triggered by TRPV4 activation, we report here a TRPV4-triggered vasoconstriction in the mouse aorta that involves a COX-generated Tx receptor (TP) agonist that acts in a MAPK and Src kinase signalling dependent manner. This constriction is potentiated by activation of the GPCRs for angiotensin (AT1 receptors) or proteinases (PAR1 and PAR2) via transactivation of the EGF receptor and a process involving PKC. TRPV4-dependent vascular contraction can be blocked by COX inhibitors or with TP antagonists. Further, TRPV4 activation in HUVECs stimulated Tx release as detected by an elisa. CONCLUSION AND IMPLICATIONS We conclude that the GPCR potentiation of TRPV4 action and TRPV4-dependent Tx receptor activation are important regulators of vascular function and could be therapeutically targeted in vascular diseases.
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Affiliation(s)
- Mahmoud Saifeddine
- Department of Physiology and Pharmacology, Inflammation Research Network and Snyder Institute for Chronic Disease, University of Calgary, Calgary, AB, Canada
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