1
|
Soslau G. Platelet protein synthesis, regulation, and post-translational modifications: mechanics and function. Crit Rev Biochem Mol Biol 2023; 58:99-117. [PMID: 37347996 DOI: 10.1080/10409238.2023.2224532] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/08/2023] [Indexed: 06/24/2023]
Abstract
Dogma had been firmly entrenched in the minds of the scientific community that the anucleate mammalian platelet was incapable of protein biosynthesis since their identification in the late 1880s. These beliefs were not challenged until the 1960s when several reports demonstrated that platelets possessed the capacity to biosynthesize proteins. Even then, many still dismissed the synthesis as trivial and unimportant for at least another two decades. Research in the field expanded after the 1980s and numerous reports have since been published that now clearly demonstrate the potential significance of platelet protein synthesis under normal, pathological, and activating conditions. It is now clear that the platelet proteome is not a static entity but can be altered slowly or rapidly in response to external signals to support physiological requirements to maintain hemostasis and other biological processes. All the necessary biological components to support protein synthesis have been identified in platelets along with post-transcriptional processing of mRNAs, regulators of translation, and post-translational modifications such as glycosylation. The last comprehensive review of the subject appeared in 2009 and much work has been conducted since that time. The current review of the field will briefly incorporate the information covered in earlier reviews and then bring the reader up to date with more recent findings.
Collapse
Affiliation(s)
- Gerald Soslau
- Department of Biochemistry and Molecular Biology Drexel University College of Medicine, Philadelphia, PA, United States
| |
Collapse
|
2
|
Saqib U, Munjuluri S, Sarkar S, Biswas S, Mukherjee O, Satsangi H, Baig MS, Obukhov AG, Hajela K. Transient Receptor Potential Canonical 6 (TRPC6) Channel in the Pathogenesis of Diseases: A Jack of Many Trades. Inflammation 2023:10.1007/s10753-023-01808-3. [PMID: 37072606 PMCID: PMC10112830 DOI: 10.1007/s10753-023-01808-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/18/2023] [Accepted: 03/23/2023] [Indexed: 04/20/2023]
Abstract
The mammalian Transient Receptor Potential Canonical (TRPC) subfamily comprises seven transmembrane proteins (TRPC1-7) forming cation channels in the plasma membrane of mammalian cells. TRPC channels mediate Ca2+ and Na+ influx into the cells. Amongst TRPCs, TRPC6 deficiency or increased activity due to gain-of-function mutations has been associated with a multitude of diseases, such as kidney disease, pulmonary disease, and neurological disease. Indeed, the TRPC6 protein is expressed in various organs and is involved in diverse signalling pathways. The last decade saw a surge in the investigative studies concerning the physiological roles of TRPC6 and describing the development of new pharmacological tools modulating TRPC6 activity. The current review summarizes the progress achieved in those investigations.
Collapse
Affiliation(s)
- Uzma Saqib
- School of Life Sciences, Devi Ahilya Vishwavidyalaya, Vigyan Bhawan, Khandwa Road Campus, Indore, 452 001, MP, India
| | - Sreepadaarchana Munjuluri
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA
| | - Sutripta Sarkar
- Post Graduate Department of Food and Nutrition, Barrackpore Rastraguru Surendranath College, 85, Middle Road, Barrackpore, 700120, West Bengal, India
| | - Subir Biswas
- Ramky One Galaxia, Nallagandla, Hyderabad, 500019, Telangana, India
| | - Oyshi Mukherjee
- Post Graduate Department of Food and Nutrition, Barrackpore Rastraguru Surendranath College, 85, Middle Road, Barrackpore, 700120, West Bengal, India
| | | | - Mirza S Baig
- Department of Biosciences and Biomedical Engineering (BSBE), Indian Institute of Technology Indore (IITI), Indore, India
| | - Alexander G Obukhov
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
- Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
| | - Krishnan Hajela
- School of Life Sciences, Devi Ahilya Vishwavidyalaya, Vigyan Bhawan, Khandwa Road Campus, Indore, 452 001, MP, India.
| |
Collapse
|
3
|
Tan Y, Lu W, Yi X, Cai H, Yuan Y, Zhang S. Improvement of platelet preservation by inhibition of TRPC6. Transfus Med 2023. [PMID: 36746770 DOI: 10.1111/tme.12955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 12/27/2022] [Accepted: 01/16/2023] [Indexed: 02/08/2023]
Abstract
BACKGROUND The preservation of platelets (PLTs) by room temperature (RT) oscillation limits their shelf life to between 4 and 7 days because of the decrease in PLT function. TRPC6 is a non-selective mechanically sensitive cation channel that has been shown to mediate Ca2+ signalling, implying a role in PLT activation during preservation by RT oscillation. OBJECTIVES This study was designed to investigate whether inhibition of TRPC6 can improve the RT preservation of PLTs and the possible underlying mechanism. METHODS Human PLTs from whole blood were stored at 22 ± 2°C with oscillation in plasma or M-sol (mixture of solutions). BI-749327, a specific TRPC6 inhibitor, was administered throughout the preservation period. PLT distribution width (PDW), mean platelet volume (MPV), maximum platelet aggregation rate (MAR) and average aggregation rate (AAR) were measured. The MTT method was used to assess the relative viability of PLTs. Flow cytometry was used to measure the changes of Ca2+ concentration in PLTs and phosphatidylserine (PS) exposure on the PLT surface, and western blotting was used to assess the expression changes of platelet TRPC6 and CD62P proteins. RESULTS Compared with the control group, inhibition of TRPC6 with BI-749327 significantly reduced the PDW, MPV and Ca2+ concentration, the MAR and AAR were significantly increased, the expression of TRPC6 and CD62P protein was significantly down-regulated in PLTs, and the PS exposure was significantly reduced on the PLT surface. However, these effects were all reversed by activation of TRPC6. CONCLUSION Inhibition of TRPC6 improves the quality of PLT preservation by inhibiting the Ca2+ signal mediated by TRPC6.
Collapse
Affiliation(s)
- Yuanjia Tan
- Third-Grade Pharmacological Laboratory on Traditional Chinese Medicine, China Three Gorges University, Yichang, China.,Department of Physiology, Medical College of China Three Gorges University, Yichang, China
| | - Wei Lu
- Office, The Blood Bank Center of Yichang City, Yichang, China
| | - Xiaomei Yi
- Office, The Blood Bank Center of Yichang City, Yichang, China
| | - Huili Cai
- Department of Hematology, Yichang Central People' Hospital, The First College of Clinical Medical Science, China Three Gorges University, Yichang, China
| | - Yurong Yuan
- Office, The Blood Bank Center of Yichang City, Yichang, China
| | - Shizhong Zhang
- Third-Grade Pharmacological Laboratory on Traditional Chinese Medicine, China Three Gorges University, Yichang, China.,Department of Physiology, Medical College of China Three Gorges University, Yichang, China
| |
Collapse
|
4
|
Kazandzhieva K, Mammadova-Bach E, Dietrich A, Gudermann T, Braun A. TRP channel function in platelets and megakaryocytes: basic mechanisms and pathophysiological impact. Pharmacol Ther 2022; 237:108164. [PMID: 35247518 DOI: 10.1016/j.pharmthera.2022.108164] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/29/2022] [Accepted: 02/28/2022] [Indexed: 12/30/2022]
Abstract
Transient receptor potential (TRP) proteins form a superfamily of cation channels that are expressed in a wide range of tissues and cell types. During the last years, great progress has been made in understanding the molecular complexity and the functions of TRP channels in diverse cellular processes, including cell proliferation, migration, adhesion and activation. The diversity of functions depends on multiple regulatory mechanisms by which TRP channels regulate Ca2+ entry mechanisms and intracellular Ca2+ dynamics, either through membrane depolarization involving cation influx or store- and receptor-operated mechanisms. Abnormal function or expression of TRP channels results in vascular pathologies, including hypertension, ischemic stroke and inflammatory disorders through effects on vascular cells, including the components of blood vessels and platelets. Moreover, some TRP family members also regulate megakaryopoiesis and platelet production, indicating a complex role of TRP channels in pathophysiological conditions. In this review, we describe potential roles of TRP channels in megakaryocytes and platelets, as well as their contribution to diseases such as thrombocytopenia, thrombosis and stroke. We also critically discuss the potential of TRP channels as possible targets for disease prevention and treatment.
Collapse
Affiliation(s)
- Kalina Kazandzhieva
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany
| | - Elmina Mammadova-Bach
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany; Division of Nephrology, Department of Medicine IV, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Alexander Dietrich
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany; German Center for Lung Research (DZL), Munich, Germany
| | - Thomas Gudermann
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany; German Center for Lung Research (DZL), Munich, Germany.
| | - Attila Braun
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany.
| |
Collapse
|
5
|
Boekell KL, Brown BJ, Talbot BE, Schlondorff JS. Trpc6 gain-of-function disease mutation enhances phosphatidylserine exposure in murine platelets. PLoS One 2022; 17:e0270431. [PMID: 35749414 PMCID: PMC9231752 DOI: 10.1371/journal.pone.0270431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 06/09/2022] [Indexed: 01/28/2023] Open
Abstract
Platelets enhance coagulation by exposing phosphatidylserine (PS) on their cell surface in response to strong agonist activation. Transient receptor potential channels, including TRPC6, have been implicated in the calcium influx central to this process. Here, we characterize the effect of a Trpc6 gain-of-function (GOF) disease-associated, and a dominant negative (DN), mutation on murine platelet activation. Platelets from mice harboring Trpc6E896K/E896K (GOF) and Trpc6DN/DN mutations were subject to in vitro analysis. Trpc6E896K/E896K and Trpc6DN/DN mutant platelets show enhanced and absent calcium influx, respectively, upon addition of the TRPC3/6 agonist GSK1702934A (GSK). GSK was sufficient to induce integrin αIIbβ3 activation, P-selection and PS exposure, talin cleavage, and MLC2 phosphorylation in Trpc6E896K/E896K, but not in wild-type, platelets. Thrombin-induced calcium influx and PS exposure were enhanced, and clot retraction delayed, by GOF TRPC6, while no differences were noted between wild-type and Trpc6DN/DN platelets. In contrast, Erk activation upon GSK treatment was absent in Trpc6DN/DN, and enhanced in Trpc6E896K/E896K, platelets, compared to wild-type. The positive allosteric modulator, TRPC6-PAM-C20, and fluoxetine maintained their ability to enhance and inhibit, respectively, GSK-mediated calcium influx in Trpc6E896K/E896K platelets. The data demonstrate that gain-of-function mutant TRPC6 channel can enhance platelet activation, including PS exposure, while confirming that TRPC6 is not necessary for this process. Furthermore, the results suggest that Trpc6 GOF disease mutants do not simply increase wild-type TRPC6 responses, but can affect pathways not usually modulated by TRPC6 channel activity, displaying a true gain-of-function phenotype.
Collapse
Affiliation(s)
- Kimber L. Boekell
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brittney J. Brown
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Brianna E. Talbot
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Johannes S. Schlondorff
- Department of Medicine, Division of Nephrology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
| |
Collapse
|
6
|
Zainal Abidin NA, Poon EKW, Szydzik C, Timofeeva M, Akbaridoust F, Brazilek RJ, Tovar Lopez FJ, Ma X, Lav C, Marusic I, Thompson PE, Mitchell A, Ooi ASH, Hamilton JR, Nesbitt WS. An extensional strain sensing mechanosome drives adhesion-independent platelet activation at supraphysiological hemodynamic gradients. BMC Biol 2022; 20:73. [PMID: 35331224 PMCID: PMC8944166 DOI: 10.1186/s12915-022-01274-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 03/07/2022] [Indexed: 11/20/2022] Open
Abstract
Background Supraphysiological hemodynamics are a recognized driver of platelet activation and thrombosis at high-grade stenosis and in blood contacting circulatory support devices. However, whether platelets mechano-sense hemodynamic parameters directly in free flow (in the absence of adhesion receptor engagement), the specific hemodynamic parameters at play, the precise timing of activation, and the signaling mechanism(s) involved remain poorly elucidated. Results Using a generalized Newtonian computational model in combination with microfluidic models of flow acceleration and quasi-homogenous extensional strain, we demonstrate that platelets directly mechano-sense acute changes in free-flow extensional strain independent of shear strain, platelet amplification loops, von Willebrand factor, and canonical adhesion receptor engagement. We define an extensional strain sensing “mechanosome” in platelets involving cooperative Ca2+ signaling driven by the mechanosensitive channel Piezo1 (as the primary strain sensor) and the fast ATP gated channel P2X1 (as the secondary signal amplifier). We demonstrate that type II PI3 kinase C2α activity (acting as a “clutch”) couples extensional strain to the mechanosome. Conclusions Our findings suggest that platelets are adapted to rapidly respond to supraphysiological extensional strain dynamics, rather than the peak magnitude of imposed wall shear stress. In the context of overall platelet activation and thrombosis, we posit that “extensional strain sensing” acts as a priming mechanism in response to threshold levels of extensional strain allowing platelets to form downstream adhesive interactions more rapidly under the limiting effects of supraphysiological hemodynamics. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01274-7.
Collapse
Affiliation(s)
- Nurul A Zainal Abidin
- The Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, 3004, Australia
| | - Eric K W Poon
- Department of Medicine, St Vincent's Hospital, Melbourne Medical School, Faculty of Medicine, Dentistry & Health Sciences, The University of Melbourne, Fitzroy, VIC, 3065, Australia
| | - Crispin Szydzik
- The Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, 3004, Australia.,School of Engineering, RMIT University, La Trobe Street, Melbourne, VIC, 3004, Australia
| | - Mariia Timofeeva
- Department of Mechanical Engineering, Faculty of Engineering and Information Technology, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Farzan Akbaridoust
- Department of Mechanical Engineering, Faculty of Engineering and Information Technology, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Rose J Brazilek
- The Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, 3004, Australia
| | | | - Xiao Ma
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Chitrarth Lav
- Department of Mechanical Engineering, Faculty of Engineering and Information Technology, The University of Melbourne, Melbourne, VIC, 3010, Australia.,CFD Methodology Group, Scuderia AlphaTauri F1, Bicester, OX26 4LD, UK
| | - Ivan Marusic
- Department of Mechanical Engineering, Faculty of Engineering and Information Technology, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Philip E Thompson
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Arnan Mitchell
- School of Engineering, RMIT University, La Trobe Street, Melbourne, VIC, 3004, Australia
| | - Andrew S H Ooi
- Department of Mechanical Engineering, Faculty of Engineering and Information Technology, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Justin R Hamilton
- The Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, 3004, Australia
| | - Warwick S Nesbitt
- The Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, 3004, Australia.
| |
Collapse
|
7
|
CRACking the Molecular Regulatory Mechanism of SOCE during Platelet Activation in Thrombo-Occlusive Diseases. Cells 2022; 11:cells11040619. [PMID: 35203269 PMCID: PMC8870035 DOI: 10.3390/cells11040619] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 01/31/2022] [Accepted: 02/09/2022] [Indexed: 11/16/2022] Open
Abstract
Thrombo-occlusive diseases such as myocardial infarction, ischemic stroke and deep vein thrombosis with subsequent pulmonary embolism still represent a major health burden worldwide. Besides the cells of the vasculature or other hematopoietic cells, platelets are primarily responsible for the development and progression of an occluding thrombus. The activation and function of platelets crucially depend on free cytosolic calcium (Ca2+) as second messenger, which modulates platelet secretion, aggregation and thrombus formation. Ca2+ is elevated upon platelet activation by release of Ca2+ from intracellular stores thus triggering of the subsequent store-operated Ca2+ entry (SOCE), which is facilitated by Ca2+ release-activated channels (CRACs). In general, CRACs are assembled by the pore-forming unit Orai in the plasma membrane and the Ca2+-sensing stromal interaction molecule (STIM) in the endoplasmic reticulum after the depletion of internal Ca2+ stores. In the last few years, there is a growing body of the literature demonstrating the importance of STIM and Orai-mediated mechanism in thrombo-occlusive disorders. Thus, this review provides an overview of the recent understanding of STIM and Orai signaling in platelet function and its implication in the development and progression of ischemic thrombo-occlusive disorders. Moreover, potential pharmacological implications of STIM and Orai signaling in platelets are anticipated and discussed in the end.
Collapse
|
8
|
Shawer H, Norman K, Cheng CW, Foster R, Beech DJ, Bailey MA. ORAI1 Ca 2+ Channel as a Therapeutic Target in Pathological Vascular Remodelling. Front Cell Dev Biol 2021; 9:653812. [PMID: 33937254 PMCID: PMC8083964 DOI: 10.3389/fcell.2021.653812] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/08/2021] [Indexed: 12/21/2022] Open
Abstract
In the adult, vascular smooth muscle cells (VSMC) are normally physiologically quiescent, arranged circumferentially in one or more layers within blood vessel walls. Remodelling of native VSMC to a proliferative state for vascular development, adaptation or repair is driven by platelet-derived growth factor (PDGF). A key effector downstream of PDGF receptors is store-operated calcium entry (SOCE) mediated through the plasma membrane calcium ion channel, ORAI1, which is activated by the endoplasmic reticulum (ER) calcium store sensor, stromal interaction molecule-1 (STIM1). This SOCE was shown to play fundamental roles in the pathological remodelling of VSMC. Exciting transgenic lineage-tracing studies have revealed that the contribution of the phenotypically-modulated VSMC in atherosclerotic plaque formation is more significant than previously appreciated, and growing evidence supports the relevance of ORAI1 signalling in this pathologic remodelling. ORAI1 has also emerged as an attractive potential therapeutic target as it is accessible to extracellular compound inhibition. This is further supported by the progression of several ORAI1 inhibitors into clinical trials. Here we discuss the current knowledge of ORAI1-mediated signalling in pathologic vascular remodelling, particularly in the settings of atherosclerotic cardiovascular diseases (CVDs) and neointimal hyperplasia, and the recent developments in our understanding of the mechanisms by which ORAI1 coordinates VSMC phenotypic remodelling, through the activation of key transcription factor, nuclear factor of activated T-cell (NFAT). In addition, we discuss advances in therapeutic strategies aimed at the ORAI1 target.
Collapse
Affiliation(s)
- Heba Shawer
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Katherine Norman
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom.,School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - Chew W Cheng
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Richard Foster
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom.,School of Chemistry, University of Leeds, Leeds, United Kingdom
| | - David J Beech
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| | - Marc A Bailey
- School of Medicine, The Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds, United Kingdom
| |
Collapse
|
9
|
Shekhar S, Liu Y, Wang S, Zhang H, Fang X, Zhang J, Fan L, Zheng B, Roman RJ, Wang Z, Fan F, Booz GW. Novel Mechanistic Insights and Potential Therapeutic Impact of TRPC6 in Neurovascular Coupling and Ischemic Stroke. Int J Mol Sci 2021; 22:2074. [PMID: 33669830 PMCID: PMC7922996 DOI: 10.3390/ijms22042074] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/12/2021] [Accepted: 02/17/2021] [Indexed: 12/13/2022] Open
Abstract
Ischemic stroke is one of the most disabling diseases and a leading cause of death globally. Despite advances in medical care, the global burden of stroke continues to grow, as no effective treatments to limit or reverse ischemic injury to the brain are available. However, recent preclinical findings have revealed the potential role of transient receptor potential cation 6 (TRPC6) channels as endogenous protectors of neuronal tissue. Activating TRPC6 in various cerebral ischemia models has been found to prevent neuronal death, whereas blocking TRPC6 enhances sensitivity to ischemia. Evidence has shown that Ca2+ influx through TRPC6 activates the cAMP (adenosine 3',5'-cyclic monophosphate) response element-binding protein (CREB), an important transcription factor linked to neuronal survival. Additionally, TRPC6 activation may counter excitotoxic damage resulting from glutamate release by attenuating the activity of N-methyl-d-aspartate (NMDA) receptors of neurons by posttranslational means. Unresolved though, are the roles of TRPC6 channels in non-neuronal cells, such as astrocytes and endothelial cells. Moreover, TRPC6 channels may have detrimental effects on the blood-brain barrier, although their exact role in neurovascular coupling requires further investigation. This review discusses evidence-based cell-specific aspects of TRPC6 in the brain to assess the potential targets for ischemic stroke management.
Collapse
Affiliation(s)
- Shashank Shekhar
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Jin Zhang
- School of Medicine, I.M. Sechenov First Moscow State Medical University, Moscow 119048, Russia
| | - Letao Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Baoying Zheng
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Richard J. Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Zhen Wang
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, USA;
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - George W. Booz
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| |
Collapse
|
10
|
Froghi S, Grant CR, Tandon R, Quaglia A, Davidson B, Fuller B. New Insights on the Role of TRP Channels in Calcium Signalling and Immunomodulation: Review of Pathways and Implications for Clinical Practice. Clin Rev Allergy Immunol 2021; 60:271-292. [PMID: 33405100 PMCID: PMC7985118 DOI: 10.1007/s12016-020-08824-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2020] [Indexed: 12/14/2022]
Abstract
Calcium is the most abundant mineral in the human body and is central to many physiological processes, including immune system activation and maintenance. Studies continue to reveal the intricacies of calcium signalling within the immune system. Perhaps the most well-understood mechanism of calcium influx into cells is store-operated calcium entry (SOCE), which occurs via calcium release-activated channels (CRACs). SOCE is central to the activation of immune system cells; however, more recent studies have demonstrated the crucial role of other calcium channels, including transient receptor potential (TRP) channels. In this review, we describe the expression and function of TRP channels within the immune system and outline associations with murine models of disease and human conditions. Therefore, highlighting the importance of TRP channels in disease and reviewing potential. The TRP channel family is significant, and its members have a continually growing number of cellular processes. Within the immune system, TRP channels are involved in a diverse range of functions including T and B cell receptor signalling and activation, antigen presentation by dendritic cells, neutrophil and macrophage bactericidal activity, and mast cell degranulation. Not surprisingly, these channels have been linked to many pathological conditions such as inflammatory bowel disease, chronic fatigue syndrome and myalgic encephalomyelitis, atherosclerosis, hypertension and atopy.
Collapse
Affiliation(s)
- Saied Froghi
- Department of HPB & Liver Transplantation, Royal Free Hospital, Pond St, Hampstead, London, NW3 2QG, UK. .,Division of Surgery & Interventional Sciences/University College London (UCL), Royal Free Hospital, Pond Street, Hampstead, London, NW3 2QG, UK. .,HCA Senior Clinical Fellow (HPB & Liver Transplant), Wellington Hospital, St Johns Wood, London, UK.
| | - Charlotte R Grant
- Department of HPB & Liver Transplantation, Royal Free Hospital, Pond St, Hampstead, London, NW3 2QG, UK
| | - Radhika Tandon
- Sheffield Medical School, Beech Hill Road, Sheffield, UK, S10 2RX
| | - Alberto Quaglia
- Department of Pathology, Royal Free Hospital, Pond Street, Hampstead, London, NW3 2QG, UK
| | - Brian Davidson
- Department of HPB & Liver Transplantation, Royal Free Hospital, Pond St, Hampstead, London, NW3 2QG, UK.,Division of Surgery & Interventional Sciences/University College London (UCL), Royal Free Hospital, Pond Street, Hampstead, London, NW3 2QG, UK
| | - Barry Fuller
- Division of Surgery & Interventional Sciences/University College London (UCL), Royal Free Hospital, Pond Street, Hampstead, London, NW3 2QG, UK
| |
Collapse
|
11
|
Platelets and Defective N-Glycosylation. Int J Mol Sci 2020; 21:ijms21165630. [PMID: 32781578 PMCID: PMC7460655 DOI: 10.3390/ijms21165630] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/04/2020] [Accepted: 08/04/2020] [Indexed: 12/13/2022] Open
Abstract
N-glycans are covalently linked to an asparagine residue in a simple acceptor sequence of proteins, called a sequon. This modification is important for protein folding, enhancing thermodynamic stability, and decreasing abnormal protein aggregation within the endoplasmic reticulum (ER), for the lifetime and for the subcellular localization of proteins besides other functions. Hypoglycosylation is the hallmark of a group of rare genetic diseases called congenital disorders of glycosylation (CDG). These diseases are due to defects in glycan synthesis, processing, and attachment to proteins and lipids, thereby modifying signaling functions and metabolic pathways. Defects in N-glycosylation and O-glycosylation constitute the largest CDG groups. Clotting and anticlotting factor defects as well as a tendency to thrombosis or bleeding have been described in CDG patients. However, N-glycosylation of platelet proteins has been poorly investigated in CDG. In this review, we highlight normal and deficient N-glycosylation of platelet-derived molecules and discuss the involvement of platelets in the congenital disorders of N-glycosylation.
Collapse
|
12
|
Ortiz-Muñoz G, Yu MA, Lefrançais E, Mallavia B, Valet C, Tian JJ, Ranucci S, Wang KM, Liu Z, Kwaan N, Dawson D, Kleinhenz ME, Khasawneh FT, Haggie PM, Verkman AS, Looney MR. Cystic fibrosis transmembrane conductance regulator dysfunction in platelets drives lung hyperinflammation. J Clin Invest 2020; 130:2041-2053. [PMID: 31961827 PMCID: PMC7108932 DOI: 10.1172/jci129635] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 01/14/2020] [Indexed: 12/11/2022] Open
Abstract
Cystic fibrosis (CF) lung disease is characterized by an inflammatory response that can lead to terminal respiratory failure. The cystic fibrosis transmembrane conductance regulator (CFTR) is mutated in CF, and we hypothesized that dysfunctional CFTR in platelets, which are key participants in immune responses, is a central determinant of CF inflammation. We found that deletion of CFTR in platelets produced exaggerated acute lung inflammation and platelet activation after intratracheal LPS or Pseudomonas aeruginosa challenge. CFTR loss of function in mouse or human platelets resulted in agonist-induced hyperactivation and increased calcium entry into platelets. Inhibition of the transient receptor potential cation channel 6 (TRPC6) reduced platelet activation and calcium flux, and reduced lung injury in CF mice after intratracheal LPS or Pseudomonas aeruginosa challenge. CF subjects receiving CFTR modulator therapy showed partial restoration of CFTR function in platelets, which may be a convenient approach to monitoring biological responses to CFTR modulators. We conclude that CFTR dysfunction in platelets produces aberrant TRPC6-dependent platelet activation, which is a major driver of CF lung inflammation and impaired bacterial clearance. Platelets and TRPC6 are what we believe to be novel therapeutic targets in the treatment of CF lung disease.
Collapse
Affiliation(s)
| | - Michelle A. Yu
- Department of Medicine, UCSF, San Francisco, California, USA
| | - Emma Lefrançais
- Department of Medicine, UCSF, San Francisco, California, USA
| | - Beñat Mallavia
- Department of Medicine, UCSF, San Francisco, California, USA
| | - Colin Valet
- Department of Medicine, UCSF, San Francisco, California, USA
| | | | - Serena Ranucci
- Department of Medicine, UCSF, San Francisco, California, USA
| | - Kristin M. Wang
- Department of Medicine, UCSF, San Francisco, California, USA
| | - Zhe Liu
- Department of Medicine, UCSF, San Francisco, California, USA
| | - Nicholas Kwaan
- Department of Medicine, UCSF, San Francisco, California, USA
| | - Diana Dawson
- Department of Medicine, UCSF, San Francisco, California, USA
| | | | - Fadi T. Khasawneh
- School of Pharmacy, University of Texas, El Paso, El Paso, Texas, USA
| | - Peter M. Haggie
- Department of Medicine, UCSF, San Francisco, California, USA
- Department of Physiology and
| | - Alan S. Verkman
- Department of Medicine, UCSF, San Francisco, California, USA
- Department of Physiology and
| | - Mark R. Looney
- Department of Medicine, UCSF, San Francisco, California, USA
- Department of Laboratory Medicine, UCSF, San Francisco, California, USA
| |
Collapse
|
13
|
Paez Espinosa EV, Lin OA, Karim ZA, Alshbool FZ, Khasawneh FT. Mouse transient receptor potential channel type 6 selectively regulates agonist-induced platelet function. Biochem Biophys Rep 2019; 20:100685. [PMID: 31508510 PMCID: PMC6726914 DOI: 10.1016/j.bbrep.2019.100685] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 08/27/2019] [Accepted: 08/27/2019] [Indexed: 01/20/2023] Open
Abstract
While changes in intracellular calcium levels is a central step in platelet activation and thrombus formation, the contribution and mechanism of receptor-operated calcium entry (ROCE) via transient receptor potential channels (TRPCs) in platelets remains poorly defined. In previous studies, we have shown that TRPC6 regulates hemostasis and thrombosis, in mice. In the present studies, we employed a knockout mouse model system to characterize the role of TRPC6 in ROCE and platelet activation. It was observed that the TRPC6 deletion (Trpc6−/−) platelets displayed impaired elevation of intracellular calcium, i.e., defective ROCE. Moreover, these platelets also exhibited defects in a host of functional responses, namely aggregation, granule secretion, and integrin αIIbβ3. Interestingly, the aforementioned defects were specific to the thromboxane receptor (TPR), as no impaired responses were observed in response to ADP or the thrombin receptor-activating peptide 4 (TRAP4). The defect in ROCE in the Trpc6−/− was also observed with 1-oleoyl-2-acetyl-sn-glycerol (OAG). Finally, our studies also revealed that TRPC6 regulates clot retraction. Taken together, our findings demonstrate that TRPC6 directly regulates TPR-dependent ROCE and platelet function. Thus, TRPC6 may serve as a novel target for the therapeutic management of thrombotic diseases. TRPC6 regulates TPR-mediated/receptor-operated calcium entry. TRPC6 regulates TPR-dependent platelet aggregation, secretion and integrin activation. TRPC6 regulates clot retraction. TRPC6 expression levels are age-dependent in platelets.
Collapse
Affiliation(s)
| | | | - Zubair A Karim
- 1101 N. Campbell St, Pharmaceutical Sciences, School of Pharmacy, The University of Texas El Paso, El Paso, TX, 79902, USA
| | - Fatima Z Alshbool
- 1101 N. Campbell St, Pharmaceutical Sciences, School of Pharmacy, The University of Texas El Paso, El Paso, TX, 79902, USA
| | - Fadi T Khasawneh
- 1101 N. Campbell St, Pharmaceutical Sciences, School of Pharmacy, The University of Texas El Paso, El Paso, TX, 79902, USA
| |
Collapse
|
14
|
|
15
|
Discovery and characterization of a positive allosteric modulator of transient receptor potential canonical 6 (TRPC6) channels. Cell Calcium 2018; 78:26-34. [PMID: 30594060 DOI: 10.1016/j.ceca.2018.12.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 12/20/2018] [Accepted: 12/20/2018] [Indexed: 01/13/2023]
Abstract
The non-selective second messenger-gated cation channel TRPC6 (transient receptor potential canonical 6) is activated by diacylglycerols (DAG) in a PKC-independent manner and plays important roles in a variety of physiological processes and diseases. In order to facilitate novel therapies, the development of potent inhibitors as well as channel-activating agents is of great interest. The screening of a chemical library, comprising about 17,000 small molecule compounds, revealed an agent, which induced increases in intracellular Ca2+ concentrations ([Ca2+]i) in a concentration-dependent manner (EC50 = 2.37 ± 0.25 μM) in stably TRPC6-expressing HEK293 cells. This new compound (C20) selectively acts on TRPC6, unlike OAG (1-oleoyl-1-acetyl-sn-glycerol), which also activates PKC and does not discriminate between TRPC6 and the closely related channels TRPC3 and TRPC7. Further evaluation by Ca2+ assays and electrophysiological studies revealed that C20 rather operated as an enhancer of channel activation than as an activator by itself and led to the assumption that the compound C20 is an allosteric modulator of TRPC6, enabling low basal concentrations of DAG to induce activation of the ion channel. Furthermore, C20 was tested in human platelets that express TRPC6. A combined activation of TRPC6 with C20 and OAG elicited a robust increase in [Ca2+]i in human platelets. This potentiated channel activation was sensitive to TRPC6 channel blockers. To achieve sufficient amounts of C20 for biological studies, we applied a one-pot synthesis strategy. With regard to studies in native systems, the sensitizing ability of C20 can be a valuable pharmacological tool to selectively exaggerate TRPC6-dependent signals.
Collapse
|
16
|
Store-operated calcium entry in thrombosis and thrombo-inflammation. Cell Calcium 2018; 77:39-48. [PMID: 30530092 DOI: 10.1016/j.ceca.2018.11.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 10/31/2018] [Accepted: 11/14/2018] [Indexed: 01/03/2023]
Abstract
Cytosolic free calcium (Ca2+) is a second messenger regulating a wide variety of functions in blood cells, including adhesion, activation, proliferation and migration. Store-operated Ca2+ entry (SOCE), triggered by depletion of Ca2+ from the endoplasmic reticulum, provides a main mechanism of regulated Ca2+ influx in blood cells. SOCE is mediated and regulated by isoforms of the ion channel proteins ORAI and TRP, and the transmembrane Ca2+ sensors stromal interaction molecules (STIMs), respectively. This report provides an overview of the (patho)physiological importance of SOCE in blood cells implicated in thrombosis and thrombo-inflammation, i.e. platelets and immune cells. We also discuss the physiological consequences of dysregulated SOCE in platelets and immune cells and the potential of SOCE inhibition as a therapeutic option to prevent or treat arterial thrombosis as well as thrombo-inflammatory disease states such as ischemic stroke.
Collapse
|
17
|
Krauszman A, Mak TW, Szaszi K, Kuebler WM. Role of phosphatase and tensin homolog in hypoxic pulmonary vasoconstriction. Cardiovasc Res 2018; 113:869-878. [PMID: 28430879 DOI: 10.1093/cvr/cvx076] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 04/16/2017] [Indexed: 01/26/2023] Open
Abstract
Aims Hypoxic pulmonary vasoconstriction (HPV) redistributes blood flow from poorly ventilated to better aerated areas in the lung, thereby optimizing ventilation-perfusion ratio (V/Q). Pulmonary artery smooth muscle cell (PASMC) contraction in response to hypoxia is triggered by Ca2+ influx via transient receptor potential canonical 6 (TRPC6) cation channels that have translocated to caveolae in the plasma membrane. Since phosphatase and tensin homolog (PTEN) was suggested to regulate TRPC6 in endothelial cells, we aimed to define its role in the hypoxic response of PASMCs and as a putative mediator of HPV. Methods and results In isolated perfused mouse lungs, smooth muscle specific PTEN deficiency attenuated pulmonary vasoconstriction in response to hypoxia but not to angiotensin II (Ang II). Analogously, siRNA-mediated knock down of PTEN in human PASMC inhibited the hypoxia-induced increase in cytosolic Ca2+ concentration ([Ca2+]i). Co-immunoprecipitation and proximity ligation assays revealed increased interaction of PTEN with TRPC6 in human PASMC and murine lungs in response to hypoxia. In hypoxic PASMC, both PTEN and TRPC6 translocated to caveolae, and this response was blocked by pharmacological inhibition of Rho-associated protein kinase (ROCK) which in parallel prevented PTEN-TRPC6 interaction, hypoxia-induced [Ca2+]i increase, and HPV in PASMC and murine lungs, respectively. Conclusion Our data indicate a novel interplay between ROCK and [Ca2+]i signalling in HPV via PTEN, in that ROCK mediates interaction of PTEN and TRPC6 which then conjointly translocate to caveolae allowing for Ca2+ influx into and subsequent contraction of PASMC.
Collapse
Affiliation(s)
- Adrienn Krauszman
- Department of Surgery, The Keenan Research Centre for Biomedical Science at St. Michael's Hospital, 209 Victoria Street, M5B 1T8, Toronto, ON, Canada.,Department of Physiology, Institute of Physiology, Charité - Universitaetsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Tak W Mak
- Departments of Medical Biophysics and Immunology, Campbell Family Institute for Breast Cancer Research, Princess Margaret Cancer Centre, University Health Network, 620 University Ave, M5G 2C1, Toronto, ON, Canada
| | - Katalin Szaszi
- Department of Surgery, The Keenan Research Centre for Biomedical Science at St. Michael's Hospital, 209 Victoria Street, M5B 1T8, Toronto, ON, Canada.,Department of Surgery
| | - Wolfgang M Kuebler
- Department of Surgery, The Keenan Research Centre for Biomedical Science at St. Michael's Hospital, 209 Victoria Street, M5B 1T8, Toronto, ON, Canada.,Department of Physiology, Institute of Physiology, Charité - Universitaetsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany.,Department of Surgery.,Department of Physiology, University of Toronto, 27 King's College Circle, M5S 1A1, Toronto, ON, Canada
| |
Collapse
|
18
|
Pires PW. Cannabinoids during ischemic strokes: friends or foes? Am J Physiol Heart Circ Physiol 2018; 314:H1155-H1156. [PMID: 29522356 PMCID: PMC6032081 DOI: 10.1152/ajpheart.00107.2018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 02/28/2018] [Accepted: 03/05/2018] [Indexed: 02/01/2023]
Affiliation(s)
- Paulo W Pires
- Department of Pharmacology, Center for Cardiovascular Research, Reno School of Medicine, University of Nevada , Reno, Nevada
| |
Collapse
|
19
|
López E, Gómez-Gordo L, Cantonero C, Bermejo N, Pérez-Gómez J, Granados MP, Salido GM, Rosado Dionisio JA, Redondo Liberal PC. Stanniocalcin 2 Regulates Non-capacitative Ca 2+ Entry and Aggregation in Mouse Platelets. Front Physiol 2018; 9:266. [PMID: 29628897 PMCID: PMC5876523 DOI: 10.3389/fphys.2018.00266] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 03/08/2018] [Indexed: 12/11/2022] Open
Abstract
Stanniocalcin 2 (STC2) is a fish protein that controls body Ca2+ and phosphate metabolism. STC2 has also been described in mammals, and as platelet function highly depends on both extracellular and intracellular Ca2+, we have explored its expression and function in these cells. STC2−/− mice exhibit shorter tail bleeding time than WT mice. Platelets from STC2-deficient mice showed enhanced aggregation, as well as enhanced Ca2+ mobilization in response to the physiological agonist thrombin (Thr) and the diacylglycerol analog, OAG, a selective activator of the non-capacitative Ca2+ entry channels. Interestingly, platelets from STC2−/− mice exhibit attenuated interaction between STIM1 and Orai1 in response to Thr, thus suggesting that STC2 is required for Thr-evoked STIM1-Orai1 interaction and the subsequent store-operated Ca2+ entry (SOCE). We have further assessed possible changes in the expression of the most relevant channels involved in non-capacitative Ca2+ entry in platelets. Then, protein expression of Orai3, TRPC3 and TRPC6 were evaluated by Western blotting, and the results revealed that while the expression of Orai3 was enhanced in the STC2-deficient mice, others like TRPC3 and TRPC6 remains almost unaltered. Summarizing, our results provide for the first time evidence for a role of STC2 in platelet physiology through the regulation of agonist-induced Ca2+ entry, which might be mediated by the regulation of Orai3 channel expression.
Collapse
Affiliation(s)
- Esther López
- Department of Physiology (PHYCELL) of the Veterinary Faculty, University of Extremadura, Cáceres, Spain
| | - L Gómez-Gordo
- Department of Animal Medicine, Veterinary Faculty University of Extremadura, Cáceres, Spain
| | - Carlos Cantonero
- Department of Physiology (PHYCELL) of the Veterinary Faculty, University of Extremadura, Cáceres, Spain
| | - Nuria Bermejo
- Hematology Unit, San Pedro de Alcantara Hospital, Cáceres, Spain
| | - Jorge Pérez-Gómez
- Faculty of Sport Sciences, University of Extremadura, Cáceres, Spain
| | - María P Granados
- Aldea Moret Health Center, Extremadura Health Service, Cáceres, Spain
| | - Gines M Salido
- Institute of Molecular Pathology Biomarkers, Cáceres, Spain
| | - Juan A Rosado Dionisio
- Department of Physiology (PHYCELL) of the Veterinary Faculty, University of Extremadura, Cáceres, Spain
| | - Pedro C Redondo Liberal
- Department of Physiology (PHYCELL) of the Veterinary Faculty, University of Extremadura, Cáceres, Spain
| |
Collapse
|
20
|
Makhoul S, Walter E, Pagel O, Walter U, Sickmann A, Gambaryan S, Smolenski A, Zahedi RP, Jurk K. Effects of the NO/soluble guanylate cyclase/cGMP system on the functions of human platelets. Nitric Oxide 2018; 76:71-80. [PMID: 29550521 DOI: 10.1016/j.niox.2018.03.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 03/03/2018] [Accepted: 03/12/2018] [Indexed: 02/07/2023]
Abstract
Platelets are circulating sentinels of vascular integrity and are activated, inhibited, or modulated by multiple hormones, vasoactive substances or drugs. Endothelium- or drug-derived NO strongly inhibits platelet activation via activation of the soluble guanylate cyclase (sGC) and cGMP elevation, often in synergy with cAMP-elevation by prostacyclin. However, the molecular mechanisms and diversity of cGMP effects in platelets are poorly understood and sometimes controversial. Recently, we established the quantitative human platelet proteome, the iloprost/prostacyclin/cAMP/protein kinase A (PKA)-regulated phosphoproteome, and the interactions of the ADP- and iloprost/prostacyclin-affected phosphoproteome. We also showed that the sGC stimulator riociguat is in vitro a highly specific inhibitor, via cGMP, of various functions of human platelets. Here, we review the regulatory role of the cGMP/protein kinase G (PKG) system in human platelet function, and our current approaches to establish and analyze the phosphoproteome after selective stimulation of the sGC/cGMP pathway by NO donors and riociguat. Present data indicate an extensive and diverse NO/riociguat/cGMP phosphoproteome, which has to be compared with the cAMP phosphoproteome. In particular, sGC/cGMP-regulated phosphorylation of many membrane proteins, G-proteins and their regulators, signaling molecules, protein kinases, and proteins involved in Ca2+ regulation, suggests that the sGC/cGMP system targets multiple signaling networks rather than a limited number of PKG substrate proteins.
Collapse
Affiliation(s)
- Stephanie Makhoul
- University Medical Center Mainz, Center for Thrombosis and Hemostasis (CTH), Mainz, Germany
| | - Elena Walter
- University Medical Center Mainz, Center for Thrombosis and Hemostasis (CTH), Mainz, Germany
| | - Oliver Pagel
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V., Dortmund, Germany
| | - Ulrich Walter
- University Medical Center Mainz, Center for Thrombosis and Hemostasis (CTH), Mainz, Germany
| | - Albert Sickmann
- Leibniz-Institut für Analytische Wissenschaften - ISAS - e. V., Dortmund, Germany; Ruhr Universität Bochum, Medizinisches Proteom Center, Medizinische Fakultät, Bochum, Germany; Department of Chemistry, College of Physical Sciences, University of Aberdeen, Aberdeen, UK
| | - Stepan Gambaryan
- University Medical Center Mainz, Center for Thrombosis and Hemostasis (CTH), Mainz, Germany; Russian Academy of Sciences, Sechenov Institute of Evolutionary Physiology and Biochemistry, St. Petersburg, Russia; St. Petersburg State University, Department of Cytology and Histology, St. Petersburg, Russia
| | - Albert Smolenski
- Conway Institute of Biomolecular & Biomedical Research, Univ. College Dublin, Dublin, Ireland; Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - René P Zahedi
- Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University , Montreal, Quebec H4A 3T2, Canada; Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University , Montreal, Quebec H3T 1E2, Canada
| | - Kerstin Jurk
- University Medical Center Mainz, Center for Thrombosis and Hemostasis (CTH), Mainz, Germany.
| |
Collapse
|
21
|
Ilkan Z, Watson S, Watson SP, Mahaut-Smith MP. P2X1 Receptors Amplify FcγRIIa-Induced Ca2+ Increases and Functional Responses in Human Platelets. Thromb Haemost 2018; 118:369-380. [PMID: 29443373 PMCID: PMC6260114 DOI: 10.1160/th17-07-0530] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Platelets express key receptors of the innate immune system such as FcγRIIa and Toll-like receptors (TLR). P2X1 cation channels amplify the platelet responses to several major platelet stimuli, particularly glycoprotein (GP)VI and TLR2/1, whereas their contribution to Src tyrosine kinase-dependent FcγRIIa receptors remains unknown. We investigated the role of P2X1 receptors during activation of FcγRIIa in human platelets, following stimulation by cross-linking of an anti-FcγRIIa monoclonal antibody (mAb) IV.3, or bacterial stimulation with
Streptococcus sanguinis
. Activation was assessed in washed platelet suspensions via measurement of intracellular Ca
2+
([Ca
2+
]
i
) increases, ATP release and aggregation. P2X1 activity was abolished by pre-addition of α,β-meATP, exclusion of apyrase or the antagonist NF449. FcγRIIa activation evoked a robust increase in [Ca
2+
]
i
(441 ± 33 nM at 30 μg/mL mAb), which was reduced to a similar extent (to 66–70% of control) by NF449, pre-exposure to α,β-meATP or apyrase omission, demonstrating a significant P2X1 receptor contribution. FcγRIIa activation-dependent P2X1 responses were partially resistant to nitric oxide (NO), but abrogated by 500 nM prostacyclin (PGI
2
). Aggregation responses to bacteria and FcγRIIa activation were also inhibited by P2X1 receptor desensitization (to 66 and 42% of control, respectively). However, FcγRIIa-mediated tyrosine phosphorylation and ATP release were not significantly altered by the loss of P2X1 activity. In conclusion, we show that P2X1 receptors enhance platelet FcγRIIa receptor-evoked aggregation through an increase in [Ca
2+
]
i
downstream of the initial tyrosine phosphorylation events and early dense granule release. This represents a further route whereby ATP-gated cation channels can contribute to platelet-dependent immune responses in vivo.
Collapse
Affiliation(s)
- Zeki Ilkan
- Department of Molecular and Cell Biology, Henry Wellcome Building, University of Leicester, Leicester, United Kingdom
| | - Stephanie Watson
- Institute of Cardiovascular Sciences, Institute of Biomedical Research Building, University of Birmingham, Birmingham, United Kingdom
| | - Steve P Watson
- Institute of Cardiovascular Sciences, Institute of Biomedical Research Building, University of Birmingham, Birmingham, United Kingdom.,Centre of Membrane Proteins and Receptors (COMPARE), Universities of Birmingham and Nottingham, Midlands, UK
| | - Martyn P Mahaut-Smith
- Department of Molecular and Cell Biology, Henry Wellcome Building, University of Leicester, Leicester, United Kingdom
| |
Collapse
|
22
|
Nagy M, Mastenbroek TG, Mattheij NJA, de Witt S, Clemetson KJ, Kirschner J, Schulz AS, Vraetz T, Speckmann C, Braun A, Cosemans JMEM, Zieger B, Heemskerk JWM. Variable impairment of platelet functions in patients with severe, genetically linked immune deficiencies. Haematologica 2017; 103:540-549. [PMID: 29242293 PMCID: PMC5830379 DOI: 10.3324/haematol.2017.176974] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 12/07/2017] [Indexed: 11/09/2022] Open
Abstract
In patients with dysfunctions of the Ca2+ channel ORAI1, stromal interaction molecule 1 (STIM1) or integrin-regulating kindlin-3 (FERMT3), severe immunodeficiency is frequently linked to abnormal platelet activity. In this paper, we studied platelet responsiveness by multiparameter assessment of whole blood thrombus formation under high-shear flow conditions in 9 patients, including relatives, with confirmed rare genetic mutations of ORAI1, STIM1 or FERMT3. In platelets isolated from 5 out of 6 patients with ORAI1 or STIM1 mutations, store-operated Ca2+ entry (SOCE) was either completely or partially defective compared to control platelets. Parameters of platelet adhesion and aggregation on collagen microspots were impaired for 4 out of 6 patients, in part related to a low platelet count. For 4 patients, platelet adhesion/aggregation and procoagulant activity on von Willebrand Factor (VWF)/rhodocytin and VWF/fibrinogen microspots were impaired independently of platelet count, and were partly correlated with SOCE deficiency. Measurement of thrombus formation at low shear rate confirmed a greater impairment of platelet functionality in the ORAI1 patients than in the STIM1 patient. For 3 patients/relatives with a FERMT3 mutation, all parameters of thrombus formation were strongly reduced regardless of the microspot. Bone marrow transplantation, required by 2 patients, resulted in overall improvement of platelet function. We concluded that multiparameter assessment of whole blood thrombus formation in a surface-dependent way can detect: i) additive effects of low platelet count and impaired platelet functionality; ii) aberrant ORAI1-mediated Ca2+ entry; iii) differences in platelet activation between patients carrying the same ORAI1 mutation; iv) severe platelet function impairment linked to a FERMT3 mutation and bleeding history.
Collapse
Affiliation(s)
- Magdolna Nagy
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands
| | - Tom G Mastenbroek
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands
| | - Nadine J A Mattheij
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands
| | - Susanne de Witt
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands
| | | | - Janbernd Kirschner
- Department of Neuropediatrics and Muscle Disorders, Medical Center, University of Freiburg, Germany
| | - Ansgar S Schulz
- Department of Pediatrics and Adolescent Medicine, University Medical Centre Ulm, Germany
| | - Thomas Vraetz
- Department of Pediatrics and Adolescent Medicine, Medical Center-University of Freiburg, Faculty of Medicine, Germany
| | - Carsten Speckmann
- Center for Chronic Immunodeficiency and Department of Pediatrics and Adolescent Medicine, Medical Centre, University of Freiburg, Germany
| | - Attila Braun
- Institute of Experimental Biomedicine, University Hospital and Rudolf Virchow Centre, University of Würzburg, Germany
| | - Judith M E M Cosemans
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands
| | - Barbara Zieger
- Center for Chronic Immunodeficiency and Department of Pediatrics and Adolescent Medicine, Medical Centre, University of Freiburg, Germany
| | - Johan W M Heemskerk
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, the Netherlands
| |
Collapse
|
23
|
Li CH, Chen C, Zhang Q, Tan CN, Hu YJ, Li P, Wan JB, Feng G, Xia ZN, Yang FQ. Differential proteomic analysis of platelets suggested target-related proteins in rabbit platelets treated with Rhizoma Corydalis. PHARMACEUTICAL BIOLOGY 2017; 55:76-87. [PMID: 27653279 PMCID: PMC7011957 DOI: 10.1080/13880209.2016.1229340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
CONTEXT Corydalis yanhusuo W.T. Wang (Papaveraceae) (Rhizoma Corydalis) showed inhibitory effects on rabbit platelet aggregation induced by ADP, thrombin (THR) or arachidonic acid (AA). OBJECTIVE This study separates and identifies the possible target-related platelet proteins and suggests possible signal cascades of RC antiplatelet aggregation. MATERIALS AND METHODS Based on comparative proteomics, the differentially expressed platelet proteins treated before and after with 50 mg/mL RC 90% ethanol extract (for 15 min at 37 °C) were analyzed and identified by two dimensional gel electrophoresis (2-DE) and MALDI-TOF-MS/MS. To further verify the possible signalling pathways of RC antiplatelet aggregation function, the concentration of calcium (Ca2+) was measured by Fura-2/AM fluorescence (Ex 340/380 nm, Em 500 nm) (RC final concentrations of 0.0156-0.1563 mg/mL), the levels of P-selectin and cyclic guanosine monophosphate (cGMP) were quantified by ELISA (OD. 450 nm) (RC final concentrations of 0.0156-1.5625 mg/mL), and the 5-hydroxytryptamine (5-HT) level was measured using ortho-phthalaldehyde (OPT) fluorescence (Ex 340 nm, Em 470 nm) (RC final concentrations of 0.3125-1.5625 mg/mL). RESULTS The expression of 52 proteins were altered in rabbit platelets after the treatment and the MALDI-TOF-MS analysis indicated that those proteins include 12 cytoskeleton proteins, 7 cell signalling proteins, 3 molecular chaperone proteins, 6 proteins related to platelet function, 16 enzymes and 7 other related proteins. Furthermore, RC extract could decrease the levels of 5-HT [inhibition rate of 96.80% (p < 0.05, vs. THR-activated group) treated with 0.7813 mg/mL of RC], Ca2+ [172.73 ± 5.07 to 113.56 ± 5.46 nM (p < 0.001, vs. THR-activated group) treated with 0.0313 mg/mL of RC] and P-selectin [13.48 ± 0.96 ng/3 × 108 to 11.64 ± 0.17 ng/3 × 108 (p < 0.05, vs. THR-activated group) treated with 0.0156 mg/mL of RC], and increase in cGMP level [38.93 ± 0.57 to 50.26 ± 4.05 ng/3 × 108 (p < 0.05, vs. THR-activated group) treated with 1.5165 mg/mL of RC] in ADP (10 μmol/L), THR (0.25 u/mL) or AA-(0.205 mmol/L) activated rabbit platelets. DISCUSSION AND CONCLUSION The present study indicated that P2Y12 receptor might be one of the direct target proteins of RC in platelets. The signal cascades network of RC after binding with P2Y12 receptor is mediating Gαi proteins to activate downstream signalling pathways (AC and/or PI3K signalling pathways) for the inhibition of platelet aggregation.
Collapse
Affiliation(s)
- Chun-Hong Li
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, China
| | - Cen Chen
- Division of Imaging Science & Biomedical Engineering, King's College, London, UK
| | - Qian Zhang
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, China
| | - Chen-Ning Tan
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, China
| | - Yuan-Jia Hu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Peng Li
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Jian-Bo Wan
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Gang Feng
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, China
| | - Zhi-Ning Xia
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, China
| | - Feng-Qing Yang
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, China
- CONTACT Feng-Qing Yang, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China
| |
Collapse
|
24
|
Nakipova OV, Averin AS, Evdokimovskii EV, Pimenov OY, Kosarski L, Ignat’ev D, Anufriev A, Kokoz YM, Reyes S, Terzic A, Alekseev AE. Store-operated Ca2+ entry supports contractile function in hearts of hibernators. PLoS One 2017; 12:e0177469. [PMID: 28531217 PMCID: PMC5439705 DOI: 10.1371/journal.pone.0177469] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 04/27/2017] [Indexed: 11/30/2022] Open
Abstract
Hibernators have a distinctive ability to adapt to seasonal changes of body temperature in a range between 37°C and near freezing, exhibiting, among other features, a unique reversibility of cardiac contractility. The adaptation of myocardial contractility in hibernation state relies on alterations of excitation contraction coupling, which becomes less-dependent from extracellular Ca2+ entry and is predominantly controlled by Ca2+ release from sarcoplasmic reticulum, replenished by the Ca2+-ATPase (SERCA). We found that the specific SERCA inhibitor cyclopiazonic acid (CPA), in contrast to its effect in papillary muscles (PM) from rat hearts, did not reduce but rather potentiated contractility of PM from hibernating ground squirrels (GS). In GS ventricles we identified drastically elevated, compared to rats, expression of Orai1, Stim1 and Trpc1/3/4/5/6/7 mRNAs, putative components of store operated Ca2+ channels (SOC). Trpc3 protein levels were found increased in winter compared to summer GS, yet levels of Trpc5, Trpc6 or Trpc7 remained unchanged. Under suppressed voltage-dependent K+, Na+ and Ca2+ currents, the SOC inhibitor 2-aminoethyl diphenylborinate (2-APB) diminished whole-cell membrane currents in isolated cardiomyocytes from hibernating GS, but not from rats. During cooling-reheating cycles (30°C–7°C–30°C) of ground squirrel PM, 2-APB did not affect typical CPA-sensitive elevation of contractile force at low temperatures, but precluded the contractility at 30°C before and after the cooling. Wash-out of 2-APB reversed PM contractility to control values. Thus, we suggest that SOC play a pivotal role in governing the ability of hibernator hearts to maintain their function during the transition in and out of hibernating states.
Collapse
Affiliation(s)
- Olga V. Nakipova
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Alexey S. Averin
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Edward V. Evdokimovskii
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Pushchino, Moscow Region, Russia
| | - Oleg Yu. Pimenov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Pushchino, Moscow Region, Russia
| | - Leonid Kosarski
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Dmitriy Ignat’ev
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Andrey Anufriev
- Institute of Biology, Yakutsk Branch, Siberian Division, Russian Academy of Sciences, Yakutsk, Russia
| | - Yuri M. Kokoz
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Pushchino, Moscow Region, Russia
| | - Santiago Reyes
- Division of Cardiovascular Diseases, Department of Molecular Pharmacology and Experimental Therapeutics, Stabile 5, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Andre Terzic
- Division of Cardiovascular Diseases, Department of Molecular Pharmacology and Experimental Therapeutics, Stabile 5, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Alexey E. Alekseev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Pushchino, Moscow Region, Russia
- Division of Cardiovascular Diseases, Department of Molecular Pharmacology and Experimental Therapeutics, Stabile 5, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
| |
Collapse
|
25
|
Ilkan Z, Wright JR, Goodall AH, Gibbins JM, Jones CI, Mahaut-Smith MP. Evidence for shear-mediated Ca 2+ entry through mechanosensitive cation channels in human platelets and a megakaryocytic cell line. J Biol Chem 2017; 292:9204-9217. [PMID: 28416610 PMCID: PMC5454102 DOI: 10.1074/jbc.m116.766196] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 04/17/2017] [Indexed: 02/02/2023] Open
Abstract
The role of mechanosensitive (MS) Ca2+-permeable ion channels in platelets is unclear, despite the importance of shear stress in platelet function and life-threatening thrombus formation. We therefore sought to investigate the expression and functional relevance of MS channels in human platelets. The effect of shear stress on Ca2+ entry in human platelets and Meg-01 megakaryocytic cells loaded with Fluo-3 was examined by confocal microscopy. Cells were attached to glass coverslips within flow chambers that allowed applications of physiological and pathological shear stress. Arterial shear (1002.6 s-1) induced a sustained increase in [Ca2+] i in Meg-01 cells and enhanced the frequency of repetitive Ca2+ transients by 80% in platelets. These Ca2+ increases were abrogated by the MS channel inhibitor Grammostola spatulata mechanotoxin 4 (GsMTx-4) or by chelation of extracellular Ca2+ Thrombus formation was studied on collagen-coated surfaces using DiOC6-stained platelets. In addition, [Ca2+] i and functional responses of washed platelet suspensions were studied with Fura-2 and light transmission aggregometry, respectively. Thrombus size was reduced 50% by GsMTx-4, independently of P2X1 receptors. In contrast, GsMTx-4 had no effect on collagen-induced aggregation or on Ca2+ influx via TRPC6 or Orai1 channels and caused only a minor inhibition of P2X1-dependent Ca2+ entry. The Piezo1 agonist, Yoda1, potentiated shear-dependent platelet Ca2+ transients by 170%. Piezo1 mRNA transcripts and protein were detected with quantitative RT-PCR and Western blotting, respectively, in both platelets and Meg-01 cells. We conclude that platelets and Meg-01 cells express the MS cation channel Piezo1, which may contribute to Ca2+ entry and thrombus formation under arterial shear.
Collapse
Affiliation(s)
- Zeki Ilkan
- From the Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, United Kingdom
| | - Joy R Wright
- From the Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, United Kingdom.,the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research (NIHR) Cardiovascular Biomedical Research Unit, Glenfield Hospital, Leicester LE3 9QP, United Kingdom, and
| | - Alison H Goodall
- the Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research (NIHR) Cardiovascular Biomedical Research Unit, Glenfield Hospital, Leicester LE3 9QP, United Kingdom, and
| | - Jonathan M Gibbins
- the School of Biological Sciences, University of Reading, Reading RG6 6AS, United Kingdom
| | - Chris I Jones
- the School of Biological Sciences, University of Reading, Reading RG6 6AS, United Kingdom
| | - Martyn P Mahaut-Smith
- From the Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, United Kingdom,
| |
Collapse
|
26
|
Green TN, Hamilton JR, Morel-Kopp MC, Zheng Z, Chen TYT, Hearn JI, Sun PP, Flanagan JU, Young D, Barber PA, During MJ, Ward CM, Kalev-Zylinska ML. Inhibition of NMDA receptor function with an anti-GluN1-S2 antibody impairs human platelet function and thrombosis. Platelets 2017; 28:799-811. [PMID: 28277064 DOI: 10.1080/09537104.2017.1280149] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
GluN1 is a mandatory component of N-methyl-D-aspartate receptors (NMDARs) best known for their roles in the brain, but with increasing evidence for relevance in peripheral tissues, including platelets. Certain anti-GluN1 antibodies reduce brain infarcts in rodent models of ischaemic stroke. There is also evidence that human anti-GluN1 autoantibodies reduce neuronal damage in stroke patients, but the underlying mechanism is unclear. This study investigated whether anti-GluN1-mediated neuroprotection involves inhibition of platelet function. Four commercial anti-GluN1 antibodies were screened for their abilities to inhibit human platelet aggregation. Haematological parameters were examined in rats vaccinated with GluN1. Platelet effects of a mouse monoclonal antibody targeting the glycine-binding region of GluN1 (GluN1-S2) were tested in assays of platelet activation, aggregation and thrombus formation. The epitope of anti-GluN1-S2 was mapped and the mechanism of antibody action modelled using crystal structures of GluN1. Our work found that rats vaccinated with GluN1 had a mildly prolonged bleeding time and carried antibodies targeting mostly GluN1-S2. The monoclonal anti-GluN1-S2 antibody (from BD Biosciences) inhibited activation and aggregation of human platelets in the presence of adrenaline, adenosine diphosphate, collagen, thrombin and a protease-activated receptor 1-activating peptide. When human blood was flowed over collagen-coated surfaces, anti-GluN1-S2 impaired thrombus growth and stability. The epitope of anti-GluN1-S2 was mapped to α-helix H located within the glycine-binding clamshell of GluN1, where the antibody binding was computationally predicted to impair opening of the NMDAR channel. Our results indicate that anti-GluN1-S2 inhibits function of human platelets, including dense granule release and thrombus growth. Findings add to the evidence that platelet NMDARs regulate thrombus formation and suggest a novel mechanism by which anti-GluN1 autoantibodies limit stroke-induced neuronal damage.
Collapse
Affiliation(s)
- Taryn N Green
- a Department of Molecular Medicine and Pathology , University of Auckland , Auckland , New Zealand
| | - Justin R Hamilton
- b Australian Centre for Blood Diseases, Monash University , Melbourne , Australia
| | - Marie-Christine Morel-Kopp
- c Department of Haematology and Transfusion Medicine , Royal North Shore Hospital , Sydney , Australia.,d Northern Blood Research Centre, Kolling Institute, University of Sydney , Sydney , Australia
| | - Zhaohua Zheng
- b Australian Centre for Blood Diseases, Monash University , Melbourne , Australia
| | - Ting-Yu T Chen
- a Department of Molecular Medicine and Pathology , University of Auckland , Auckland , New Zealand.,e Department of Pharmacology and Clinical Pharmacology , University of Auckland , Auckland , New Zealand
| | - James I Hearn
- a Department of Molecular Medicine and Pathology , University of Auckland , Auckland , New Zealand
| | - Peng P Sun
- a Department of Molecular Medicine and Pathology , University of Auckland , Auckland , New Zealand
| | - Jack U Flanagan
- f Auckland Cancer Society Research Centre, University of Auckland , Auckland , New Zealand.,g Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland , Auckland , New Zealand
| | - Deborah Young
- e Department of Pharmacology and Clinical Pharmacology , University of Auckland , Auckland , New Zealand
| | - P Alan Barber
- h Department of Neurology , Auckland City Hospital , Auckland , New Zealand.,i Centre for Brain Research , University of Auckland , Auckland , New Zealand
| | - Matthew J During
- a Department of Molecular Medicine and Pathology , University of Auckland , Auckland , New Zealand.,j Departments of Molecular Virology, Immunology and Medical Genetics , Neuroscience and Neurological Surgery, Ohio State University , Columbus , OH , USA
| | - Christopher M Ward
- c Department of Haematology and Transfusion Medicine , Royal North Shore Hospital , Sydney , Australia.,d Northern Blood Research Centre, Kolling Institute, University of Sydney , Sydney , Australia
| | - Maggie L Kalev-Zylinska
- a Department of Molecular Medicine and Pathology , University of Auckland , Auckland , New Zealand.,k LabPlus Haematology , Auckland City Hospital , Auckland , New Zealand
| |
Collapse
|
27
|
Taylor KA, Pugh N. The contribution of zinc to platelet behaviour during haemostasis and thrombosis. Metallomics 2016; 8:144-55. [PMID: 26727074 DOI: 10.1039/c5mt00251f] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Platelets are the primary cellular determinants of haemostasis and pathological thrombus formation leading to myocardial infarction and stroke. Following vascular injury or atherosclerotic plaque rupture, platelets are recruited to sites of damage and undergo activation induced by a variety of soluble and/or insoluble agonists. Platelet activation is a multi-step process culminating in the formation of thrombi, which contribute to the haemostatic process. Zinc (Zn(2+)) is acknowledged as an important signalling molecule in a diverse range of cellular systems, however there is limited understanding of the influence of Zn(2+) on platelet behaviour during thrombus formation. This review evaluates the contributions of exogenous and intracellular Zn(2+) to platelet function and assesses the potential pathophysiological implications of Zn(2+) signalling. We also provide a speculative assessment of the mechanisms by which platelets could respond to changes in extracellular and intracellular Zn(2+) concentration.
Collapse
Affiliation(s)
- K A Taylor
- Department of Biomedical and Forensic Sciences, Faculty of Science and Technology, Anglia Ruskin University, Cambridge, CB1 1PT, UK.
| | - N Pugh
- Department of Biomedical and Forensic Sciences, Faculty of Science and Technology, Anglia Ruskin University, Cambridge, CB1 1PT, UK.
| |
Collapse
|
28
|
Wright JR, Amisten S, Goodall AH, Mahaut-Smith MP. Transcriptomic analysis of the ion channelome of human platelets and megakaryocytic cell lines. Thromb Haemost 2016; 116:272-84. [PMID: 27277069 PMCID: PMC5080539 DOI: 10.1160/th15-11-0891] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 04/30/2016] [Indexed: 11/05/2022]
Abstract
Ion channels have crucial roles in all cell types and represent important therapeutic targets. Approximately 20 ion channels have been reported in human platelets; however, no systematic study has been undertaken to define the platelet channelome. These membrane proteins need only be expressed at low copy number to influence function and may not be detected using proteomic or transcriptomic microarray approaches. In our recent work, quantitative real-time PCR (qPCR) provided key evidence that Kv1.3 is responsible for the voltage-dependent K+ conductance of platelets and megakaryocytes. The present study has expanded this approach to assess relative expression of 402 ion channels and channel regulatory genes in human platelets and three megakaryoblastic/erythroleukaemic cell lines. mRNA levels in platelets are low compared to other blood cells, therefore an improved method of isolating platelets was developed. This used a cocktail of inhibitors to prevent formation of leukocyte-platelet aggregates, and a combination of positive and negative immunomagnetic cell separation, followed by rapid extraction of mRNA. Expression of 34 channel-related transcripts was quantified in platelets, including 24 with unknown roles in platelet function, but that were detected at levels comparable to ion channels with established roles in haemostasis or thrombosis. Trace expression of a further 50 ion channel genes was also detected. More extensive channelomes were detected in MEG-01, CHRF-288-11 and HEL cells (195, 185 and 197 transcripts, respectively), but lacked several channels observed in the platelet. These "channelome" datasets provide an important resource for further studies of ion channel function in the platelet and megakaryocyte.
Collapse
Affiliation(s)
| | | | | | - Martyn P Mahaut-Smith
- Prof. Martyn Mahaut-Smith, PhD, Department of Molecular and Cell Biology, Henry Wellcome Building, University of Leicester, Leicester, LEI 7RH, UK, Tel.: +44 116 229 7135, E-mail:
| |
Collapse
|
29
|
Ramanathan G, Mannhalter C. Increased expression of transient receptor potential canonical 6 (TRPC6) in differentiating human megakaryocytes. Cell Biol Int 2016; 40:223-31. [PMID: 26514329 DOI: 10.1002/cbin.10558] [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: 06/19/2015] [Accepted: 10/28/2015] [Indexed: 12/22/2022]
Abstract
Members of the transient receptor potential (TRP) family of cation conducting channels are found in several tissues and cell types where they have different physiological functions. The canonical TRP channel 6 (TRPC6) is present on the platelet membrane and appears to participate in calcium influx during platelet activation. However, limited information is available on the importance of TRPC channels in megakaryocytes (MKs), the precursor cells of platelets. We determined the mRNA and protein expression of TRPC family members and investigated the role of TRPC6 for proliferation and differentiation of human MKs derived from CD34+ progenitor cells. TRPC6 transcripts were highly expressed during the differentiation of MKs and TRPC6 protein was detectable in MK cytoplasm by confocal staining. TRPC6 channel activity was modulated by pharmacological approaches using flufenamic acid (FFA) for activation and SKF96365 for inhibition. Upon FFA stimulation in MKs, an increase in intracellular calcium was observed, which was blocked by SKF96365 at 10 µM concentration. Incubation of MKs with SKF96365 resulted in a reduction in thrombopoietin-stimulated cell proliferation. Our results suggest a role of TRPC6 in calcium homeostasis during MK development, particularly for cell proliferation.
Collapse
Affiliation(s)
| | - Christine Mannhalter
- Department of Laboratory Medicine, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
30
|
Bouron A, Chauvet S, Dryer S, Rosado JA. Second Messenger-Operated Calcium Entry Through TRPC6. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:201-49. [PMID: 27161231 DOI: 10.1007/978-3-319-26974-0_10] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Canonical transient receptor potential 6 (TRPC6) proteins assemble into heteromultimeric structures forming non-selective cation channels. In addition, many TRPC6-interacting proteins have been identified like some enzymes, channels, pumps, cytoskeleton-associated proteins, immunophilins, or cholesterol-binding proteins, indicating that TRPC6 are engaged into macromolecular complexes. Depending on the cell type and the experimental conditions used, TRPC6 activity has been reported to be controlled by diverse modalities. For instance, the second messenger diacylglycerol, store-depletion, the plant extract hyperforin or H2O2 have all been shown to trigger the opening of TRPC6 channels. A well-characterized consequence of TRPC6 activation is the elevation of the cytosolic concentration of Ca(2+). This latter response can reflect the entry of Ca(2+) through open TRPC6 channels but it can also be due to the Na(+)/Ca(2+) exchanger (operating in its reverse mode) or voltage-gated Ca(2+) channels (recruited in response to a TRPC6-mediated depolarization). Although TRPC6 controls a diverse array of biological functions in many tissues and cell types, its pathophysiological functions are far from being fully understood. This chapter covers some key features of TRPC6, with a special emphasis on their biological significance in kidney and blood cells.
Collapse
Affiliation(s)
- Alexandre Bouron
- Université Grenoble Alpes, 38000, Grenoble, France. .,CNRS, iRTSV-LCBM, 38000, Grenoble, France.
| | - Sylvain Chauvet
- Université Grenoble Alpes, 38000, Grenoble, France.,CNRS, iRTSV-LCBM, 38000, Grenoble, France
| | - Stuart Dryer
- University of Houston, Houston, TX, USA.,Baylor College of Medicine, Houston, TX, USA
| | - Juan A Rosado
- Departamento de Fisiología, University of Extremadura, Cáceres, Spain
| |
Collapse
|
31
|
Berna-Erro A, Jardín I, Smani T, Rosado JA. Regulation of Platelet Function by Orai, STIM and TRP. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:157-81. [PMID: 27161229 DOI: 10.1007/978-3-319-26974-0_8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Agonist-induced changes in cytosolic Ca(2+) concentration ([Ca(2+)]c) are central events in platelet physiology. A major mechanism supporting agonist-induced Ca(2+) signals is store-operated Ca(2+) entry (SOCE), where the Ca(2+) sensor STIM1 and the channels of the Orai family, as well as TRPC members are the key elements. STIM1-dependent SOCE plays a major role in collagen-stimulated Ca(2+) signaling, phosphatidylserine exposure and thrombin generation. Furthermore, studies involving Orai1 gain-of-function mutants and platelets from Orai1-deficient mice have revealed the importance of this channel in thrombosis and hemostasis to those found in STIM1-deficient mice indicating that SOCE might play a prominent role in thrombus formation. Moreover, increase in TRPC6 expression might lead to thrombosis in humans. The role of STIM1, Orai1 and TRPCs, and thus SOCE, in thrombus formation, suggests that therapies directed against SOCE and targeting these molecules during cardiovascular and cerebrovascular events could significantly improve traditional anti-thrombotic treatments.
Collapse
Affiliation(s)
- Alejandro Berna-Erro
- Laboratory of Molecular Physiology and Channelopathies, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, 08003, Spain
| | - Isaac Jardín
- Department of Physiology (Cell Physiology Research Group), University of Extremadura, Cáceres, 10003, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysic, Institute of Biomedicine of Seville (IBiS), University Hospital of Virgen del Rocío/CSIC/University of Seville, Sevilla, 41013, Spain
| | - Juan A Rosado
- Departamento de Fisiología, University of Extremadura, Cáceres, Spain.
| |
Collapse
|
32
|
Lopez E, Berna-Erro A, Salido GM, Rosado JA, Redondo PC. FKBP25 and FKBP38 regulate non-capacitative calcium entry through TRPC6. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2684-96. [PMID: 26239116 DOI: 10.1016/j.bbamcr.2015.07.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 07/27/2015] [Accepted: 07/30/2015] [Indexed: 10/23/2022]
Abstract
Non-capacitative calcium entry (NCCE) contributes to cell activation in response to the occupation of G protein-coupled membrane receptors. Thrombin administration to platelets evokes the synthesis of diacylglycerol downstream of PAR receptor activation. Diacylglycerol evokes NCCE through activating TRPC3 and TRPC6 in human platelets. Although it is known that immunophilins interact with TRPCs, the role of immunophilins in the regulation of NCCE remains unknown. Platelet incubation with FK506, an immunophilin antagonist, reduced OAG-evoked NCCE in a concentration-dependent manner, an effect that was independent on the inactivation of calcineurin (CaN). FK506 was unable to reduce NCCE evoked by OAG in platelets from TRPC6-/- mice. In HEK-293 cells overexpressing TRPC6, currents through TRPC6 were altered in the presence of FK506. We have found interaction between FKBP38 and other FKBPs, like FKBP25, FKBP12, and FKBP52 that were not affected by FK506, as well as with calmodulin (CaM). FK506 modified the pattern of association between FKBP25 and TRPCs as well as impaired OAG-evoked TRPC3 and TRPC6 coupling in both human and mouse platelets. By performing biotinylation experiments we have elucidated that FKBP25 and FKBP38 might be found at different cellular location, the plasma membrane and the already described intracellular locations. Finally, FKBP25 and FKBP38 silencing significantly inhibits OAG-evoked NCCE in MEG-01 and HEK293 cells, while overexpression of FKBP38 does not modify NCCE in HEK293 cells. All together, these findings provide strong evidence for a role of immunophilins, including FKBP25 and FKBP38, in NCCE mediated by TRPC6.
Collapse
Affiliation(s)
- Esther Lopez
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain
| | - Alejandro Berna-Erro
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain
| | - Gines M Salido
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain
| | - Pedro C Redondo
- Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain.
| |
Collapse
|
33
|
Abstract
Blood platelet activation must be tightly regulated to ensure a balance between haemostasis and thrombosis. The cAMP signalling pathway is the most powerful endogenous regulator of blood platelet activation. PKA (protein kinase A), the foremost effector of cAMP signalling in platelets, phosphorylates a number of proteins that are thought to modulate multiple aspects of platelet activation. In the present mini-review, we outline our current understanding of cAMP-mediated platelet inhibition and discuss some of the issues that require clarification.
Collapse
|
34
|
Vemana HP, Karim ZA, Conlon C, Khasawneh FT. A critical role for the transient receptor potential channel type 6 in human platelet activation. PLoS One 2015; 10:e0125764. [PMID: 25928636 PMCID: PMC4416038 DOI: 10.1371/journal.pone.0125764] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 03/25/2015] [Indexed: 12/31/2022] Open
Abstract
While calcium signaling is known to play vital roles in platelet function, the mechanisms underlying its receptor-operated calcium entry component (ROCE) remain poorly understood. It has been proposed, but never proven in platelets, that the canonical transient receptor potential channel-6 (TRPC6) mediates ROCE. Nonetheless, we have previously shown that the mouse TRPC6 regulates hemostasis, thrombogenesis by regulating platelet aggregation. In the present studies, we used a pharmacological approach to characterize the role of TRPC6 in human platelet biology. Thus, interestingly, we observed that a TRPC6 inhibitor exerted significant inhibitory effects on human platelet aggregation in a thromboxane receptor (TPR)-selective manner; no additional inhibition was observed in the presence of the calcium chelator BAPTA. This inhibitor also significantly inhibited human platelet secretion (dense and alpha granules), integrin IIb-IIIa, Akt and ERK phosphorylation, again, in a TPR-selective manner; no effects were observed in response to ADP receptor stimulation. Furthermore, there was a causal relationship between these inhibitory effects, and the capacity of the TRPC6 inhibitor to abrogate elevation in intracellular calcium, that was again found to be TPR-specific. This effect was not found to be due to antagonism of TPR, as the TRPC6 inhibitor did not displace the radiolabeled antagonist [3H]SQ29,548 from its binding sites. Finally, our studies also revealed that TRPC6 regulates human clot retraction, as well as physiological hemostasis and thrombus formation, in mice. Taken together, our findings demonstrate, for the first time, that TRPC6 directly regulates TPR-dependent ROCE and platelet function. Moreover, these data highlight TRPC6 as a novel promising therapeutic strategy for managing thrombotic disorders.
Collapse
Affiliation(s)
- Hari Priya Vemana
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California, United States of America
| | - Zubair A. Karim
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California, United States of America
| | - Christine Conlon
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California, United States of America
| | - Fadi T. Khasawneh
- Department of Pharmaceutical Sciences, College of Pharmacy, Western University of Health Sciences, Pomona, California, United States of America
- * E-mail:
| |
Collapse
|
35
|
Phosphatidylinositol-3,4,5-trisphosphate stimulates Ca(2+) elevation and Akt phosphorylation to constitute a major mechanism of thromboxane A2 formation in human platelets. Cell Signal 2015; 27:1488-98. [PMID: 25797048 DOI: 10.1016/j.cellsig.2015.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 02/18/2015] [Accepted: 03/04/2015] [Indexed: 11/23/2022]
Abstract
Phosphatidylinositol trisphosphate (PIP3) has been implicated in many platelet functions however many of the mechanisms need clarification. We have used cell permeable analogues of PIP3,1-O-(1,2-di-palmitoyl-sn-glyero-3-O-phosphoryl)-D-myo-inositol-3,4,5-trisphosphate (DiC16-PIP3) or 1-O-(1,2-di-octanoyl-sn-glyero-3-O-phosphoryl)-D-myo-inositol-3,4,5-trisphosphate (DiC8-PIP3) to study their effects on activation on washed human platelets. Addition of either DiC8- or DiC16-PIP3 to human platelets induced aggregation in the presence of extracellular Ca(2+). This was reduced by the presence of indomethacin, the phospholipase C inhibitor U73122 and apyrase. DiC8-PIP3 induced the phosphorylation of Akt-Ser(473) which was reduced by the Akt inhibitor IV, wortmannin and EGTA (suggesting a dependence on Ca(2+) entry). In Fura2 loaded platelets DiC8-PIP3 was effective at increasing intracellular Ca(2+) in a distinct and transient manner that was reduced in the presence of indomethacin, U73122 and 2-aminoethyl diphenylborinate (2APB). Ca(2+) elevation was reduced by the non-SOCE inhibitor LOE908 and also by the SOCE inhibitor BTP2. DiC8-PIP3 induced the release of Ca(2+) from stores which was not affected by the proton dissipating agent bafilomycin A1 and was more potent than the two-pore channel agonist DiC8-PI[3,5]P2 suggesting release from an endoplasmic reticulum type store. DiC8-PIP3 weakly induced the tyrosine phosphorylation of Syk but not of PLCγ2. Finally like thrombin DiC8-PIP3 induced the formation of thromboxane B2 that was inhibited by the Akt inhibitor IV. These studies suggest that PIP3 via Ca(2+) elevation and Akt phosphorylation forms a central role in thromboxane A2 formation and the amplification of platelet activation.
Collapse
|
36
|
Michiels CF, Fransen P, De Munck DG, De Meyer GRY, Martinet W. Defective autophagy in vascular smooth muscle cells alters contractility and Ca2+ homeostasis in mice. Am J Physiol Heart Circ Physiol 2015; 308:H557-67. [DOI: 10.1152/ajpheart.00659.2014] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Autophagy is an evolutionary preserved process that prevents the accumulation of unwanted cytosolic material through the formation of autophagosomes. Although autophagy has been extensively studied to understand its function in normal physiology, the role of vascular smooth muscle (SM) cell (VSMC) autophagy in Ca2+ mobilization and contraction remains poorly understood. Recent evidence shows that autophagy is involved in controlling contractile function and Ca2+ homeostasis in certain cell types. Therefore, autophagy might also regulate contractile capacity and Ca2+-mobilizing pathways in VSMCs. Contractility (organ chambers) and Ca2+ homeostasis (myograph) were investigated in aortic segments of 3.5-mo-old mice containing a SM cell-specific deletion of autophagy-related 7 ( Atg7; Atg7 fl/ fl SM22α -Cre+ mice) and in segments of corresponding control mice ( Atg7+/+ SM22α -Cre+). Our results indicate that voltage-gated Ca2+ channels (VGCCs) of Atg7 fl/ fl SM22α -Cre+ VSMCs were more sensitive to depolarization, independent of changes in resting membrane potential. Contractions elicited with K+ (50 mM) or the VGCC agonist BAY K8644 (100 nM) were significantly higher due to increased VGCC expression and activity. Interestingly, the sarcoplasmic reticulum of Atg7 fl/ fl SM22α -Cre+ VSMCs was enlarged, which, combined with increased sarco(endo)plasmic reticulum Ca2+-ATPase 2 expression and higher store-operated Ca2+ entry, promoted inositol 1,4,5-trisphosphate-mediated contractions of Atg7 fl/ fl SM22α -Cre+ segments and maximized the Ca2+ storing capacity of the sarcoplasmic reticulum. Moreover, decreased plasma membrane Ca2+-ATPase expression in Atg7 fl/ fl SM22α -Cre+ VSMCs hampered Ca2+ extrusion to the extracellular environment. Overall, our study indicates that defective autophagy in VSMCs leads to an imbalance between Ca2+ release/influx and Ca2+ reuptake/extrusion, resulting in higher basal Ca2+ concentrations and significant effects on vascular reactivity.
Collapse
Affiliation(s)
| | - Paul Fransen
- Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium
| | - Dorien G. De Munck
- Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium
| | | | - Wim Martinet
- Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium
| |
Collapse
|
37
|
Redondo PC, Rosado JA. Store-operated calcium entry: unveiling the calcium handling signalplex. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2015; 316:183-226. [PMID: 25805125 DOI: 10.1016/bs.ircmb.2015.01.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Store-operated Ca(2+) entry (SOCE) is an important mechanism for Ca(2+) influx in non-excitable cells, also present in excitable cells. The activation of store-operated channels (SOCs) is finely regulated by the filling state of the intracellular agonist-sensitive Ca(2+) compartments, and both, the mechanism of sensing the Ca(2+) stores and the nature and functional properties of the SOCs, have been a matter of intense investigation and debate. The identification of STIM1 as the endoplasmic reticulum Ca(2+) sensor and both Orai1, as the pore-forming subunit of the channels mediating the Ca(2+)-selective store-operated current, and the members of the TRPC subfamily of proteins, as the channels mediating the cation-permeable SOCs, has shed new light on the underlying events. This review summarizes the initial hypothesis and the current advances on the mechanism of activation of SOCE.
Collapse
Affiliation(s)
- Pedro C Redondo
- Department of Physiology, University of Extremadura, Cáceres, Spain
| | - Juan A Rosado
- Department of Physiology, University of Extremadura, Cáceres, Spain
| |
Collapse
|
38
|
Mallick RL, Kumari S, Singh N, Sonkar VK, Dash D. Prion protein fragment (106-126) induces prothrombotic state by raising platelet intracellular calcium and microparticle release. Cell Calcium 2015; 57:300-11. [PMID: 25749016 DOI: 10.1016/j.ceca.2015.02.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 01/19/2015] [Accepted: 02/08/2015] [Indexed: 11/28/2022]
Abstract
Prion diseases are neurodegenerative disorders where infectious prion proteins (PrP) accumulate in brain leading to aggregation of amyloid fibrils and neuronal cell death. The amino acid sequence 106-126 from prion proteins, PrP(106-126), is highly amyloidogenic and implicated in prion-induced pathologies. As PrP is known to be expressed in blood following leakage from brain tissue, we sought to investigate its biological effects on human platelets, which have been widely employed as 'peripheral' model for neurons. Our findings suggested that, PrP(106-126) (20μM) induced dramatic 30-fold rise in intracellular calcium (from 105±30 to 3425±525nM) in platelets, which was attributable to influx from extracellular fluid with comparatively less contribution from intracellular stores. Calcium mobilization was associated with 8-10-fold stimulation in the activity of thiol protease calpain that led to partial cleavage of cytoskeleton-associated protein talin and extensive shedding of microparticles from platelets, thus transforming platelets to 'activated' phenotype. Both proteolysis of talin and microparticle release were precluded by calpeptin, a specific inhibitor of calpain. As microparticles are endowed with phosphatidylserine-enriched surface and hence are pro-coagulant in nature, exposure to prion favored a thrombogenic state in the organism.
Collapse
Affiliation(s)
- Ram L Mallick
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Sharda Kumari
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Nitesh Singh
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Vijay K Sonkar
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Debabrata Dash
- Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India.
| |
Collapse
|
39
|
Reddi BA, Iannella SM, O'Connor SN, Deane AM, Willoughby SR, Wilson DP. Attenuated platelet aggregation in patients with septic shock is independent from the activity state of myosin light chain phosphorylation or a reduction in Rho kinase-dependent inhibition of myosin light chain phosphatase. Intensive Care Med Exp 2015. [PMID: 26215804 PMCID: PMC4512995 DOI: 10.1186/s40635-014-0037-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Background Impaired coagulation contributes to the morbidity and mortality associated with septic shock. Whether abnormal platelet contraction adds to the bleeding tendency is unknown. Platelets contract when Ca2+-dependent myosin light chain kinase (MLCK) phosphorylates Ser19 of myosin light chain (MLC20), promoting actin-myosin cross-bridge cycling. Contraction is opposed when myosin light chain phosphatase (MLCP) dephosphorylates MLC20. It is thought that Rho kinase (ROK) inhibits MLCP by phosphorylating Thr855 of the regulatory subunit MYPT, favouring platelet contraction. This study tested the hypotheses that in septic shock, (i) platelet function is inversely correlated with illness severity and (ii) ROK-dependent MLCP inhibition and myosin light chain phosphorylation are reduced. Methods Blood was sampled from non-septic shock patients and patients in the first 24 h of septic shock. Platelet function was assessed using whole blood impedance aggregation induced by 1) ADP (1.6 and 6.5 μM), 2) thrombin receptor-activating protein (TRAP; 32 μM), 3) arachidonic acid (500 μM) and 4) collagen (3.2 μg/ml). Arachidonic acid-induced aggregation was measured in the presence of the ROK inhibitor Y27632. Illness severity was evaluated using sequential organ failure assessment (SOFA) and acute physiology and chronic health evaluation (APACHE) II scores. Western blot analysis of [Ser19]MLC20 and [Thr855]MYPT phosphorylation quantified activation and inhibition of platelet MLC20 and MLCP, respectively. Data were analysed using Spearman's rank correlation coefficient, Student's t-test and Mann-Whitney test; p < 0.05 was considered significant. Results Agonist-induced aggregation was attenuated in septic shock patients (n = 22 to 34; p < 0.05). Aggregation correlated inversely with SOFA and APACHE II scores (n = 34; p < 0.05). Thr855 phosphorylation of MYPT from unstimulated platelets was not decreased in patients with septic shock (n = 22 to 24). Both septic shock and ROK inhibition attenuated arachidonic acid-induced platelet aggregation independent of changes in [Ser19]MLC20 and [Thr855]MYPT phosphorylation (n = 14). Conclusions Impairment of whole blood aggregation in patients within the first 24 h of septic shock was correlated with SOFA and APACHE II scores. Attenuated aggregation was independent of molecular evidence of diminished platelet contraction or reduced ROK inhibition of MLCP. Efforts to restore platelet function in septic shock should therefore focus on platelet adhesion and degranulation.
Collapse
Affiliation(s)
- Benjamin Aj Reddi
- Intensive Care Unit, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia, 5000, Australia,
| | | | | | | | | | | |
Collapse
|
40
|
Protonophore properties of hyperforin are essential for its pharmacological activity. Sci Rep 2014; 4:7500. [PMID: 25511254 PMCID: PMC4266863 DOI: 10.1038/srep07500] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 11/27/2014] [Indexed: 12/13/2022] Open
Abstract
Hyperforin is a pharmacologically active component of the medicinal plant Hypericum perforatum (St. John's wort), recommended as a treatment for a range of ailments including mild to moderate depression. Part of its action has been attributed to TRPC6 channel activation. We found that hyperforin induces TRPC6-independent H+ currents in HEK-293 cells, cortical microglia, chromaffin cells and lipid bilayers. The latter demonstrates that hyperforin itself acts as a protonophore. The protonophore activity of hyperforin causes cytosolic acidification, which strongly depends on the holding potential, and which fuels the plasma membrane sodium-proton exchanger. Thereby the free intracellular sodium concentration increases and the neurotransmitter uptake by Na+ cotransport is inhibited. Additionally, hyperforin depletes and reduces loading of large dense core vesicles in chromaffin cells, which requires a pH gradient in order to accumulate monoamines. In summary the pharmacological actions of the “herbal Prozac” hyperforin are essentially determined by its protonophore properties shown here.
Collapse
|
41
|
Xu L, Chen Y, Yang K, Wang Y, Tian L, Zhang J, Wang EW, Sun D, Lu W, Wang J. Chronic hypoxia increases TRPC6 expression and basal intracellular Ca2+ concentration in rat distal pulmonary venous smooth muscle. PLoS One 2014; 9:e112007. [PMID: 25365342 PMCID: PMC4218830 DOI: 10.1371/journal.pone.0112007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 10/11/2014] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND Hypoxia causes remodeling and contractile responses in both pulmonary artery (PA) and pulmonary vein (PV). Here we explore the effect of hypoxia on PV and pulmonary venous smooth muscle cells (PVSMCs). METHODS Chronic hypoxic pulmonary hypertension (CHPH) model was established by exposing rats to 10% O2 for 21 days. Rat distal PVSMCs were isolated and cultured for in vitro experiments. The fura-2 based fluorescence calcium imaging was used to measure the basal intracellular Ca2+ concentration ([Ca2+]i) and store-operated Ca2+ entry (SOCE). Quantitative RT-PCR and western blotting were performed to measure the expression of mRNA and levels of canonical transient receptor potential (TRPC) protein respectively. RESULTS Hypoxia increased the basal [Ca2+]i and SOCE in both freshly dissociated and serum cultured distal PVSMCs. Moreover, hypoxia increased TRPC6 expression at mRNA and protein levels in both cultured PVSMCs exposed to prolonged hypoxia (4% O2, 60 h) and distal PV isolated from CHPH rats. Hypoxia also enhanced proliferation and migration of rat distal PVSMCs. CONCLUSIONS Hypoxia induces elevation of SOCE in distal PVSMCs, leading to enhancement of basal [Ca2+]i in PVSMCs. This enhancement is potentially correlated with the increased expression of TRPC6. Hypoxia triggered intracellular calcium contributes to promoted proliferation and migration of PVSMCs.
Collapse
Affiliation(s)
- Lei Xu
- Guangzhou Institute of Respiratory Diseases, State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Yuqin Chen
- Guangzhou Institute of Respiratory Diseases, State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Kai Yang
- Guangzhou Institute of Respiratory Diseases, State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Yingfeng Wang
- Guangzhou Institute of Respiratory Diseases, State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Lichun Tian
- Guangzhou Institute of Respiratory Diseases, State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Jie Zhang
- Guangzhou Institute of Respiratory Diseases, State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
| | | | - Dejun Sun
- Division of Pulmonary and Critical Care Medicine, Inner Mongolia People's Hospital, Huhhot, Inner Mongolia, China
| | - Wenju Lu
- Guangzhou Institute of Respiratory Diseases, State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
- * E-mail: (WL); (JW)
| | - Jian Wang
- Guangzhou Institute of Respiratory Diseases, State Key Laboratory of Respiratory Diseases, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China
- Division of Pulmonary and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America
- Division of Pulmonary and Critical Care Medicine, Inner Mongolia People's Hospital, Huhhot, Inner Mongolia, China
- * E-mail: (WL); (JW)
| |
Collapse
|
42
|
Abstract
STIM1 regulates TRPC6 heteromultimerization with other TRPC channels and internalization to the endoplasmic reticulum, thus reducing Ca2+ entry mediated by TRPC6.
Collapse
|
43
|
Sodhi P, Hartwick ATE. Adenosine modulates light responses of rat retinal ganglion cell photoreceptors througha cAMP-mediated pathway. J Physiol 2014; 592:4201-20. [PMID: 25038240 DOI: 10.1113/jphysiol.2014.276220] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Adenosine is an established neuromodulator in the mammalian retina, with A1 adenosine receptors being especially prevalent in the innermost ganglion cell layer. Activation of A1 receptors causes inhibition of adenylate cyclase, decreases in intracellular cyclic AMP (cAMP) levels and inhibition of protein kinase A (PKA). In this work, our aim was to characterize the effects of adenosine on the light responses of intrinsically photosensitive retinal ganglion cells (ipRGCs) and to determine whether these photoreceptors are subject to neuromodulation through intracellular cAMP-related signalling pathways. Using multielectrode array recordings from postnatal and adult rat retinas, we demonstrated that adenosine significantly shortened the duration of ipRGC photoresponses and reduced the number of light-evoked spikes fired by these neurons. The effects were A1 adenosine receptor-mediated, and the expression of this receptor on melanopsin-containing ipRGCs was confirmed by calcium imaging experiments on isolated cells in purified cultures. While inhibition of the cAMP/PKA pathway by adenosine shortened ipRGC light responses, stimulation of this pathway with compounds such as forskolin had the opposite effect and lengthened the duration of ipRGC spiking. Our findings reveal that the modification of ipRGC photoresponses through a cAMP/PKA pathway is a general feature of rat ganglion cell photoreceptors, and this pathway can be inhibited through activation of A1 receptors by adenosine. As adenosine levels in the retina rise at night, adenosinergic modulation of ipRGCs may serve as an internal regulatory mechanism to limit transmission of nocturnal photic signals by ipRGCs to the brain. Targeting retinal A1 adenosine receptors for ipRGC inhibition represents a potential therapeutic target for sleep disorders and migraine-associated photophobia.
Collapse
Affiliation(s)
- Puneet Sodhi
- Department of Neuroscience, Ohio State University, Columbus, OH, 43210, USA
| | | |
Collapse
|
44
|
Nilius B, Szallasi A. Transient Receptor Potential Channels as Drug Targets: From the Science of Basic Research to the Art of Medicine. Pharmacol Rev 2014; 66:676-814. [DOI: 10.1124/pr.113.008268] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
|
45
|
Jones S, Evans RJ, Mahaut-Smith MP. Ca2+ influx through P2X1 receptors amplifies P2Y1 receptor-evoked Ca2+ signaling and ADP-evoked platelet aggregation. Mol Pharmacol 2014; 86:243-51. [PMID: 24923466 DOI: 10.1124/mol.114.092528] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Many cells express both P2X cation channels and P2Y G-protein-coupled receptors that are costimulated by nucleotides released during physiologic or pathophysiologic responses. For example, during hemostasis and thrombosis, ATP-gated P2X1 channels and ADP-stimulated P2Y1 and P2Y12 G-protein coupled receptors play important roles in platelet activation. It has previously been reported that P2X1 receptors amplify P2Y1-evoked Ca(2+) responses in platelets, but the underlying mechanism and influence on function is unknown. In human platelets, we show that maximally activated P2X1 receptors failed to stimulate significant aggregation but could amplify the aggregation response to a submaximal concentration of ADP. Costimulation of P2X1 and P2Y1 receptors generated a superadditive Ca(2+) increase in both human platelets and human embryonic kidney 293 (HEK293) cells via a mechanism dependent on Ca(2+) influx rather than Na(+) influx or membrane depolarization. The potentiation, due to an enhanced P2Y1 response, was observed if ADP was added up to 60 seconds after P2X1 activation. P2X1 receptors also enhanced Ca(2+) responses when costimulated with type 1 protease activated and M1 muscarinic acetylcholine receptors. The P2X1-dependent amplification of Gq-coupled [Ca(2+)]i increase was mimicked by ionomycin and was not affected by inhibition of protein kinase C, Rho-kinase, or extracellular signal-regulated protein kinase 1/2, which suggests that it results from potentiation of inositol 1,4,5-trisphosphate receptors and/or phospholipase C. We conclude that Ca(2+) influx through P2X1 receptors amplifies Ca(2+) signaling through P2Y1 and other Gq-coupled receptors. This represents a general form of co-incidence detection of ATP and coreleased agonists, such as ADP at sites of vascular injury or synaptic transmitters acting at metabotropic Gq-coupled receptors.
Collapse
Affiliation(s)
- Sarah Jones
- University of Leicester, Department of Cell Physiology and Pharmacology, Leicester, United Kingdom
| | - Richard J Evans
- University of Leicester, Department of Cell Physiology and Pharmacology, Leicester, United Kingdom
| | - Martyn P Mahaut-Smith
- University of Leicester, Department of Cell Physiology and Pharmacology, Leicester, United Kingdom
| |
Collapse
|
46
|
Albarran L, Berna-Erro A, Dionisio N, Redondo PC, Lopez E, Lopez JJ, Salido GM, Brull Sabate JM, Rosado JA. TRPC6 participates in the regulation of cytosolic basal calcium concentration in murine resting platelets. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:789-96. [DOI: 10.1016/j.bbamcr.2014.01.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 01/12/2014] [Accepted: 01/13/2014] [Indexed: 10/25/2022]
|
47
|
Chen W, Thielmann I, Gupta S, Subramanian H, Stegner D, van Kruchten R, Dietrich A, Gambaryan S, Heemskerk JWM, Hermanns HM, Nieswandt B, Braun A. Orai1-induced store-operated Ca(2+) entry enhances phospholipase activity and modulates canonical transient receptor potential channel 6 function in murine platelets. J Thromb Haemost 2014; 12:528-39. [PMID: 24520961 DOI: 10.1111/jth.12525] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/16/2014] [Indexed: 08/31/2023]
Abstract
BACKGROUND Orai1, the major store-operated Ca(2+) entry (SOCE) channel in platelets, is not only critical for enhancing diverse signaling pathways, but may also regulate receptor-operated Ca(2+) entry (ROCE). Dynamic coupling of the Orai1 signalosome to canonical transient receptor potential channels (TRPCs) has been suggested as an essential step in the activation of SOCE and ROCE. However, the functional significance of the biochemical interaction between Orai and TRPC isoforms remains controversial. OBJECTIVE We aimed to elucidate the role of Orai1 in diacylglycerol (DAG)-mediated ROCE. METHODS Trpc6(-/-) , Orai1(-/-) and Orai1(-/-) /Trpc6(-/-) mice were generated, and their platelets were analyzed. RESULTS Thapsigargin (TG)-induced SOCE was further reduced in Orai1(-/-) /Trpc6(-/-) platelets as compared with Orai1(-/-) platelets, thus revealing that TG-induced signaling pathways can activate TRPC6. Thapsigargin-induced SOCE leads to enhanced phospholipase C and D activity in wild-type platelets. The activity of both enzymes was significantly reduced in Orai1(-/-) platelets upon TG stimulation, whereas receptor-induced phospholipase activity was not affected. Furthermore, TG-induced and glycoprotein VI-mediated thromboxane A2 release was strongly dependent on Orai1-mediated SOCE. CONCLUSION The regulation of TRPC6 activity can occur independently of the physical interaction with Orai1. TRPC6 operates in crosstalk with Orai1 through Orai1-induced DAG production via phospholipase activation. Orai1-induced DAG production and thromboxane release amplify the second phase of Ca(2+) signaling in platelets.
Collapse
Affiliation(s)
- W Chen
- University Hospital and Rudolf Virchow Center for Experimental Biomedicine, University of Würzburg, Würzburg, Germany
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Decichine enhances hemostasis of activated platelets via AMPA receptors. Thromb Res 2014; 133:848-54. [PMID: 24630643 DOI: 10.1016/j.thromres.2014.02.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 02/12/2014] [Accepted: 02/13/2014] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Dencichine, one of the non-protein amino acids present in the roots of Panax notoginseng, has been found to shorten bleeding time of mice and increase the number of platelets. However, the exact underlying mechanisms have not been elucidated yet. This study was aimed to identify the hemostatic effect of dencichine and uncover its mechanisms. MATERIALS AND METHODS Hemostatic effect was assessed by measuring tail bleeding time and coagulation indices of rats. PT, APTT, TT and FIB concentration were measured using a Sysmex CA-1500 plasma coagulation analyzer. Platelet aggregation rate was determined by using a platelet aggregometer. Concentration of cyotosolic calcium was evaluated by Fluo-3 and levels of cyclic adenosine monophosphate (cAMP) and thromboxane A₂ (TXA₂) were measured by ELISA method. RESULTS AND CONCLUSION Dencichine administered orally shortened tail bleeding time, reduced APTT and TT but increased the concentration of FIB in plasma in a dose-dependent manner. When induced with trap, dencichine could elevate the cytoplasmic concentration of calcium, and secretion of TXA₂ as well as the ratio of TXA₂ to PGI₂ from platelets. Meanwhile, it decreased the level of intracellular cAMP. However, CNQX could block the enhanced hemostatic effect of dencichine. These results suggested that dencichine exerted hemostatic function via AMPA receptors on platelets, therefore, facilitated coagulation cascade in a paracrine fashion by control of platelet cytosolic calcium influx, cAMP production and TXA₂ release. Current study may contribute to its clinical use in therapy of hemorrhage.
Collapse
|
49
|
Berna-Erro A, Albarran L, Dionisio N, Redondo PC, Alonso N, Gomez LJ, Salido GM, Rosado JA. The canonical transient receptor potential 6 (TRPC6) channel is sensitive to extracellular pH in mouse platelets. Blood Cells Mol Dis 2014; 52:108-15. [DOI: 10.1016/j.bcmd.2013.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 08/20/2013] [Indexed: 01/12/2023]
|
50
|
Di Buduo CA, Moccia F, Battiston M, De Marco L, Mazzucato M, Moratti R, Tanzi F, Balduini A. The importance of calcium in the regulation of megakaryocyte function. Haematologica 2014; 99:769-78. [PMID: 24463213 DOI: 10.3324/haematol.2013.096859] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Platelet release by megakaryocytes is regulated by a concert of environmental and autocrine factors. We previously showed that constitutively released adenosine diphosphate by human megakaryocytes leads to platelet production. Here we show that adenosine diphosphate elicits, in human megakaryocytes, an increase in cytosolic calcium concentration, followed by a plateau, which is lowered in the absence of extracellular calcium, suggesting the involvement of Store-Operated Calcium Entry. Indeed, we demonstrate that megakaryocytes express the major candidates to mediate Store-Operated Calcium Entry, stromal interaction molecule 1, Orai1 and canonical transient receptor potential 1, which are activated upon either pharmacological or physiological depletion of the intracellular calcium pool. This mechanism is inhibited by phospholipase C or inositol-3-phosphate receptor inhibitors and by a specific calcium entry blocker. Studies on megakaryocyte behavior, on extracellular matrix proteins that support proplatelet extension, show that calcium mobilization from intracellular stores activates signaling cascades that trigger megakaryocyte adhesion and proplatelet formation, and promotes extracellular calcium entry which is primarily involved in the regulation of the contractile force responsible for megakaryocyte motility. These findings provide the first evidence that both calcium mobilization from intracellular stores and extracellular calcium entry specifically regulate human megakaryocyte functions.
Collapse
|