1
|
Bakowski D, Murray F, Parekh AB. Store-Operated Ca 2+ Channels: Mechanism, Function, Pharmacology, and Therapeutic Targets. Annu Rev Pharmacol Toxicol 2020; 61:629-654. [PMID: 32966177 DOI: 10.1146/annurev-pharmtox-031620-105135] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Calcium (Ca2+) release-activated Ca2+ (CRAC) channels are a major route for Ca2+ entry in eukaryotic cells. These channels are store operated, opening when the endoplasmic reticulum (ER) is depleted of Ca2+, and are composed of the ER Ca2+ sensor protein STIM and the pore-forming plasma membrane subunit Orai. Recent years have heralded major strides in our understanding of the structure, gating, and function of the channels. Loss-of-function and gain-of-function mutants combined with RNAi knockdown strategies have revealed important roles for the channel in numerous human diseases, making the channel a clinically relevant target. Drugs targeting the channels generally lack specificity or exhibit poor efficacy in animal models. However, the landscape is changing, and CRAC channel blockers are now entering clinical trials. Here, we describe the key molecular and biological features of CRAC channels, consider various diseases associated with aberrant channel activity, and discuss targeting of the channels from a therapeutic perspective.
Collapse
Affiliation(s)
| | - Fraser Murray
- Pandeia Therapeutics, Oxford OX4 4GP, United Kingdom
| | - Anant B Parekh
- Department of Physiology, Anatomy and Genetics, Oxford University, Oxford OX1 3PT, United Kingdom; , .,Current affiliation: National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
| |
Collapse
|
2
|
Barak P, Parekh AB. Signaling through Ca 2+ Microdomains from Store-Operated CRAC Channels. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035097. [PMID: 31358516 DOI: 10.1101/cshperspect.a035097] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Calcium (Ca2+) ion microdomains are subcellular regions of high Ca2+ concentration that develop rapidly near open Ca2+ channels in the plasma membrane or internal stores and generate local regions of high Ca2+ concentration. These microdomains are remarkably versatile in that they activate a range of responses that differ enormously in both their temporal and spatial profile. In this review, we describe how Ca2+ microdomains generated by store-operated calcium channels, a widespread and conserved Ca2+ entry pathway, stimulate different signaling pathways, and how the spatial extent of a Ca2+ microdomain can be influenced by Ca2+ ATPase pumps.
Collapse
Affiliation(s)
- Pradeep Barak
- Department of Physiology, Anatomy, and Genetics, Oxford University, Oxford OX1 3PT, United Kingdom
| | - Anant B Parekh
- Department of Physiology, Anatomy, and Genetics, Oxford University, Oxford OX1 3PT, United Kingdom
| |
Collapse
|
3
|
Tsvilovskyy V, Solis-Lopez A, Almering J, Richter C, Birnbaumer L, Dietrich A, Freichel M. Analysis of Mrgprb2 Receptor-Evoked Ca 2+ Signaling in Bone Marrow Derived (BMMC) and Peritoneal (PMC) Mast Cells of TRPC-Deficient Mice. Front Immunol 2020; 11:564. [PMID: 32322252 PMCID: PMC7156601 DOI: 10.3389/fimmu.2020.00564] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 03/12/2020] [Indexed: 12/28/2022] Open
Abstract
Mast cells are a heterogeneous group of immune cells. The simplest and commonly accepted classification divides them in two groups according to their protease content. We have compared the action of diverse secretagogues on bone marrow derived (BMMC) and peritoneal (PMC) mast cells which represent classical models of mucosal and connective tissue type mast cells in mice. Whereas, antigen stimulation of the FcεRI receptors was similarly effective in triggering elevations of free intracellular Ca2+ concentration ([Ca2+]i) in both BMMC and PMC, robust [Ca2+]i rise following Endothelin-1 stimulation was observed only in a fraction of BMMC. Leukotriene C4 activating cysteinyl leukotriene type I receptors failed to evoke [Ca2+]i rise in either mast cell model. Stimulation of the recently identified target of many small-molecule drugs associated with systemic pseudo-allergic reactions, Mrgprb2, with compound 48/80, a mast cell activator with unknown receptor studied for many years, triggered Ca2+ oscillations in BMMC and robust [Ca2+]i rise in PMCs similarly to that evoked by FcεRI stimulation. [Ca2+]i rise in PMC could also be evoked by other Mrgprb2 agonists such as Tubocurarine, LL-37, and Substance P. The extent of [Ca2+]i rise correlated with mast cell degranulation. Expression analysis of TRPC channels as potential candidates mediating agonist evoked Ca2+ entry revealed the presence of transcripts of all members of the TRPC subfamily of TRP channels in PMCs. The amplitude and AUC of compound 48/80-evoked [Ca2+]i rise was reduced by ~20% in PMC from Trpc1/4/6−/− mice compared to Trpc1/4−/− littermatched control mice, whereas FcεRI-evoked [Ca2+]i rise was unaltered. Whole-cell patch clamp recordings showed that the reduction in compound 48/80-evoked [Ca2+]i rise in Trpc1/4/6−/− PMC was accompanied by a reduced amplitude of Compound 48/80-induced cation currents which exhibited typical features of TRPC currents. Together, this study demonstrates that PMC are an appropriate mast cell model to study mechanisms of Mrgprb2 receptor-mediated mast cell activation, and it reveals that TRPC channels contribute at least partially to Mrgprb2-mediated mast cellactivation but not following FcεRI stimulation. However, the channels conducting most of the Ca2+ entry in mast cells triggered by Mrgprb2 receptor stimulation remains to be identified.
Collapse
Affiliation(s)
- Volodymyr Tsvilovskyy
- Pharmakologisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Alejandra Solis-Lopez
- Pharmakologisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Julia Almering
- Pharmakologisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Christin Richter
- Pharmakologisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, Durham, NC, United States.,Institute for Biomedical Research (BIOMED), Catholic University of Argentina, Buenos Aires, Argentina
| | - Alexander Dietrich
- Walther-Straub Institut für Pharmakologie und Toxikologie, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Marc Freichel
- Pharmakologisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
| |
Collapse
|
4
|
Kusić D, Connolly J, Kainulainen H, Semenova EA, Borisov OV, Larin AK, Popov DV, Generozov EV, Ahmetov II, Britton SL, Koch LG, Burniston JG. Striated muscle-specific serine/threonine-protein kinase beta segregates with high versus low responsiveness to endurance exercise training. Physiol Genomics 2019; 52:35-46. [PMID: 31790338 DOI: 10.1152/physiolgenomics.00103.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Bidirectional selection for either high or low responsiveness to endurance running has created divergent rat phenotypes of high-response trainers (HRT) and low-response trainers (LRT). We conducted proteome profiling of HRT and LRT gastrocnemius of 10 female rats (body weight 279 ± 35 g; n = 5 LRT and n = 5 HRT) from generation 8 of selection. Differential analysis of soluble proteins from gastrocnemius was conducted by label-free quantitation. Genetic association studies were conducted in 384 Russian international-level athletes (age 23.8 ± 3.4 yr; 202 men and 182 women) stratified to endurance or power disciplines. Proteomic analysis encompassed 1,024 proteins, 76 of which exhibited statistically significant (P < 0.05, false discovery rate <1%) differences between HRT and LRT muscle. There was significant enrichment of enzymes involved in glycolysis/gluconeogenesis in LRT muscle but no enrichment of gene ontology phrases in HRT muscle. Striated muscle-specific serine/threonine-protein kinase-beta (SPEG-β) exhibited the greatest difference in abundance and was 2.64-fold greater (P = 0.0014) in HRT muscle. Coimmunoprecipitation identified 24 potential binding partners of SPEG-β in HRT muscle. The frequency of the G variant of the rs7564856 polymorphism that increases SPEG gene expression was significantly greater (32.9 vs. 23.8%; OR = 1.6, P = 0.009) in international-level endurance athletes (n = 258) compared with power athletes (n = 126) and was significantly associated (β = 8.345, P = 0.0048) with a greater proportion of slow-twitch fibers in vastus lateralis of female endurance athletes. Coimmunoprecipitation of SPEG-β in HRT muscle discovered putative interacting proteins that link with previously reported differences in transforming growth factor-β signaling in exercised muscle.
Collapse
Affiliation(s)
- Denis Kusić
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | | | - Heikki Kainulainen
- Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Ekaterina A Semenova
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Oleg V Borisov
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia.,Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Bonn, Germany
| | - Andrey K Larin
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Daniil V Popov
- Laboratory of Exercise Physiology, Institute of Biomedical Problems of the Russian Academy of Sciences, Moscow, Russia
| | - Edward V Generozov
- Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia
| | - Ildus I Ahmetov
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.,Department of Molecular Biology and Genetics, Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow, Russia.,Laboratory of Molecular Genetics, Kazan State Medical University, Kazan, Russia
| | - Steven L Britton
- Department of Anaesthesiology, University of Michigan, Ann Arbor, Michigan.,Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Lauren G Koch
- Department of Physiology and Pharmacology, The University of Toledo, Toledo, Ohio
| | - Jatin G Burniston
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom.,Liverpool Centre for Cardiovascular Science, Liverpool John Moores University, Liverpool, United Kingdom
| |
Collapse
|
5
|
Youm JB, Zheng H, Koh SD, Sanders KM. Na-K-2Cl Cotransporter and Store-Operated Ca 2+ Entry in Pacemaking by Interstitial Cells of Cajal. Biophys J 2019; 117:767-779. [PMID: 31400920 DOI: 10.1016/j.bpj.2019.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 06/26/2019] [Accepted: 07/11/2019] [Indexed: 01/13/2023] Open
Abstract
Pacemaker depolarization in interstitial cells of Cajal (ICCs) is believed to be induced by Ca2+ transients and activation of anoctamin-1 (Ano1) channels in the plasma membrane. However, block of store-operated calcium entry (SOCE) or the Na-K-2Cl cotransporter (NKCC1) terminates pacemaker activity in ICC, indicating these transporters are involved in the initiation or maintenance of pacemaker activity. We hypothesized that SOCE contributes to pacemaker depolarization by maintaining [Ca2+] in the endoplasmic reticulum, which is the underlying source of Ca2+ transients for activation of Ano1. NKCC1 maintains the Cl- gradient supporting the driving force for inward current mediated by Ano1. Currently mechanisms sustaining release of Ca2+ and activation of Ano1 channels during the plateau phase of slow waves are unknown, but the reverse mode of the Na+/Ca2+ exchange may contribute. We generated a mathematical model of pacemaker activity based on current empirical observations from ICC of mouse small intestine that incorporates functions of SOCE and NKCC1. This model reproduces experimental findings, suggesting roles for SOCE and Ano1 channels: blocking of either NKCC1 or SOCE in our model terminates pacemaker activity. Direct contribution of NKCC1 to pacemaker activity in a beat-to-beat manner is not predicted by our model. Instead, NKCC1 plays a maintenance role supporting the driving force for Cl- efflux. Incorporation of SOCE allows the model to drive pacemaker activity without a diastolic depolarization, as observed in cardiac pacemaking. Further biological experiments are necessary to validate and further refine the roles of NKCC1, Na+/Ca2+ exchange, and Ano1 in the pacemaker mechanism of ICC.
Collapse
Affiliation(s)
- Jae Boum Youm
- Department of Physiology, College of Medicine, Cardiovascular and Metabolic Disease Center, Inje University, Busan, Korea
| | - Haifeng Zheng
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, Nevada.
| |
Collapse
|
6
|
Samanta K, Bakowski D, Amin N, Parekh AB. The whole-cell Ca 2+ release-activated Ca 2+ current, I CRAC , is regulated by the mitochondrial Ca 2+ uniporter channel and is independent of extracellular and cytosolic Na . J Physiol 2019; 598:1753-1773. [PMID: 30582626 PMCID: PMC7318671 DOI: 10.1113/jp276551] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/05/2018] [Indexed: 12/12/2022] Open
Abstract
Key points Ca2+ entry through Ca2+ release‐activated Ca2+ channels activates numerous cellular responses. Under physiological conditions of weak intracellular Ca2+ buffering, mitochondrial Ca2+ uptake regulates CRAC channel activity. Knockdown of the mitochondrial Ca2+ uniporter channel prevented the development of ICRAC in weak buffer but not when strong buffer was used instead. Removal of either extracellular or intra‐pipette Na+ had no effect on the selectivity, kinetics, amplitude, rectification or reversal potential of whole‐cell CRAC current. Knockdown of the mitochondrial Na+–Ca2+ exchanger did not prevent the development of ICRAC in strong or weak Ca2+ buffer. Whole cell CRAC current is Ca2+‐selective. Mitochondrial Ca2+ channels, and not Na+‐dependent transport, regulate CRAC channels under physiological conditions.
Abstract Ca2+ entry through store‐operated Ca2+ release‐activated Ca2+ (CRAC) channels plays a central role in activation of a range of cellular responses over broad spatial and temporal bandwidths. Mitochondria, through their ability to take up cytosolic Ca2+, are important regulators of CRAC channel activity under physiological conditions of weak intracellular Ca2+ buffering. The mitochondrial Ca2+ transporter(s) that regulates CRAC channels is unclear and could involve the 40 kDa mitochondrial Ca2+ uniporter (MCU) channel or the Na+–Ca2+–Li+ exchanger (NCLX). Here, we have investigated the involvement of these mitochondrial Ca2+ transporters in supporting the CRAC current (ICRAC) under a range of conditions in RBL mast cells. Knockdown of the MCU channel impaired the activation of ICRAC under physiological conditions of weak intracellular Ca2+ buffering. In strong Ca2+ buffer, knockdown of the MCU channel did not inhibit ICRAC development demonstrating that mitochondria regulate CRAC channels under physiological conditions by buffering of cytosolic Ca2+ via the MCU channel. Surprisingly, manipulations that altered extracellular Na+, cytosolic Na+ or both failed to inhibit the development of ICRAC in either strong or weak intracellular Ca2+ buffer. Knockdown of NCLX also did not affect ICRAC. Prolonged removal of external Na+ also had no significant effect on store‐operated Ca2+ entry, on cytosolic Ca2+ oscillations generated by receptor stimulation or on CRAC channel‐driven gene expression. In the RBL mast cell, Ca2+ flux through the MCU but not NCLX is indispensable for activation of ICRAC. Ca2+ entry through Ca2+ release‐activated Ca2+ channels activates numerous cellular responses. Under physiological conditions of weak intracellular Ca2+ buffering, mitochondrial Ca2+ uptake regulates CRAC channel activity. Knockdown of the mitochondrial Ca2+ uniporter channel prevented the development of ICRAC in weak buffer but not when strong buffer was used instead. Removal of either extracellular or intra‐pipette Na+ had no effect on the selectivity, kinetics, amplitude, rectification or reversal potential of whole‐cell CRAC current. Knockdown of the mitochondrial Na+–Ca2+ exchanger did not prevent the development of ICRAC in strong or weak Ca2+ buffer. Whole cell CRAC current is Ca2+‐selective. Mitochondrial Ca2+ channels, and not Na+‐dependent transport, regulate CRAC channels under physiological conditions.
Collapse
Affiliation(s)
- Krishna Samanta
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - Daniel Bakowski
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - Nader Amin
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Anant B Parekh
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| |
Collapse
|
7
|
Liu YN, Lu XX, Ren A, Shi L, Zhu J, Jiang AL, Yu HS, Zhao MW. Conversion of phosphatidylinositol (PI) to PI4-phosphate (PI4P) and then to PI(4,5)P 2 is essential for the cytosolic Ca 2+ concentration under heat stress in Ganoderma lucidum. Environ Microbiol 2018; 20:2456-2468. [PMID: 29697195 DOI: 10.1111/1462-2920.14254] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/13/2018] [Accepted: 04/23/2018] [Indexed: 11/29/2022]
Abstract
How cells drive the phospholipid signal response to heat stress (HS) to maintain cellular homeostasis is a fundamental issue in biology, but the regulatory mechanism of this fundamental process is unclear. Previous quantitative analyses of lipids showed that phosphatidylinositol (PI) accumulates after HS in Ganoderma lucidum, implying the inositol phospholipid signal may be associated with HS signal transduction. Here, we found that the PI-4-kinase and PI-4-phosphate-5-kinase activities are activated and that their lipid products PI-4-phosphate and PI-4,5-bisphosphate are increased under HS. Further experimental results showed that the cytosolic Ca2+ ([Ca2+ ]c ) and ganoderic acid (GA) contents induced by HS were decreased when cells were pretreated with Li+ , an inhibitor of inositol monophosphatase, and this decrease could be rescued by PI and PI-4-phosphate. Furthermore, inhibition of PI-4-kinases resulted in a decrease in the Ca2+ and GA contents under HS that could be rescued by PI-4-phosphate but not PI. However, the decrease in the Ca2+ and GA contents by silencing of PI-4-phosphate-5-kinase could not be rescued by PI-4-phosphate. Taken together, our study reveals the essential role of the step converting PI to PI-4-phosphate and then to PI-4,5-bisphosphate in [Ca2+ ]c signalling and GA biosynthesis under HS.
Collapse
Affiliation(s)
- Yong-Nan Liu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Xiao-Xiao Lu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Ang Ren
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Liang Shi
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Jing Zhu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Ai-Liang Jiang
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Han-Shou Yu
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| | - Ming-Wen Zhao
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Microbiology Department, College of Life Sciences, Nanjing Agricultural University, Jiangsu, Nanjing 210095, People's Republic of China
| |
Collapse
|
8
|
Cyclic AMP Recruits a Discrete Intracellular Ca 2+ Store by Unmasking Hypersensitive IP 3 Receptors. Cell Rep 2017; 18:711-722. [PMID: 28099849 PMCID: PMC5276804 DOI: 10.1016/j.celrep.2016.12.058] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/17/2016] [Accepted: 12/19/2016] [Indexed: 12/12/2022] Open
Abstract
Inositol 1,4,5-trisphosphate (IP3) stimulates Ca2+ release from the endoplasmic reticulum (ER), and the response is potentiated by 3′,5′-cyclic AMP (cAMP). We investigated this interaction in HEK293 cells using carbachol and parathyroid hormone (PTH) to stimulate formation of IP3 and cAMP, respectively. PTH alone had no effect on the cytosolic Ca2+ concentration, but it potentiated the Ca2+ signals evoked by carbachol. Surprisingly, however, the intracellular Ca2+ stores that respond to carbachol alone could be both emptied and refilled without affecting the subsequent response to PTH. We provide evidence that PTH unmasks high-affinity IP3 receptors within a discrete Ca2+ store. We conclude that Ca2+ stores within the ER that dynamically exchange Ca2+ with the cytosol maintain a functional independence that allows one store to be released by carbachol and another to be released by carbachol with PTH. Compartmentalization of ER Ca2+ stores adds versatility to IP3-evoked Ca2+ signals. Cyclic AMP directly potentiates IP3-evoked Ca2+ release The Ca2+ stores released by IP3 alone or IP3 with cAMP are functionally independent Cyclic AMP unmasks high-affinity IP3 receptors in a discrete ER Ca2+ store Independent regulation of discrete Ca2+ stores increases signaling versatility
Collapse
|
9
|
Butler CT, Reynolds AL, Tosetto M, Dillon ET, Guiry PJ, Cagney G, O'Sullivan J, Kennedy BN. A Quininib Analogue and Cysteinyl Leukotriene Receptor Antagonist Inhibits Vascular Endothelial Growth Factor (VEGF)-independent Angiogenesis and Exerts an Additive Antiangiogenic Response with Bevacizumab. J Biol Chem 2016; 292:3552-3567. [PMID: 28035003 DOI: 10.1074/jbc.m116.747766] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 12/19/2016] [Indexed: 12/31/2022] Open
Abstract
Excess blood vessel growth contributes to the pathology of metastatic cancers and age-related retinopathies. Despite development of improved treatments, these conditions are associated with high economic costs and drug resistance. Bevacizumab (Avastin®), a monoclonal antibody against vascular endothelial growth factor (VEGF), is used clinically to treat certain types of metastatic cancers. Unfortunately, many patients do not respond or inevitably become resistant to bevacizumab, highlighting the need for more effective antiangiogenic drugs with novel mechanisms of action. Previous studies discovered quininib, an antiangiogenic small molecule antagonist of cysteinyl leukotriene receptors 1 and 2 (CysLT1 and CysLT2). Here, we screened a series of quininib analogues and identified a more potent antiangiogenic novel chemical entity (IUPAC name (E)-2-(2-quinolin-2-yl-vinyl)-benzene-1,4-diol HCl) hereafter designated Q8. Q8 inhibits developmental angiogenesis in Tg(fli1:EGFP) zebrafish and inhibits human microvascular endothelial cell (HMEC-1) proliferation, tubule formation, and migration. Q8 elicits antiangiogenic effects in a VEGF-independent in vitro model of angiogenesis and exerts an additive antiangiogenic response with the anti-VEGF biologic bevacizumab. Cell-based receptor binding assays confirm that Q8 is a CysLT1 antagonist and is sufficient to reduce cellular levels of NF-κB and calpain-2 and secreted levels of the proangiogenic proteins intercellular adhesion molecule-1, vascular cell adhesion protein-1, and VEGF. Distinct reductions of VEGF by bevacizumab explain the additive antiangiogenic effects observed in combination with Q8. In summary, Q8 is a more effective antiangiogenic drug compared with quininib. The VEGF-independent activity coupled with the additive antiangiogenic response observed in combination with bevacizumab demonstrates that Q8 offers an alternative therapeutic strategy to combat resistance associated with conventional anti-VEGF therapies.
Collapse
Affiliation(s)
- Clare T Butler
- From the UCD School of Biomolecular and Biomedical Science, UCD Conway Institute and
| | - Alison L Reynolds
- From the UCD School of Biomolecular and Biomedical Science, UCD Conway Institute and
| | - Miriam Tosetto
- Centre for Colorectal Disease, St. Vincent's University Hospital, Dublin 4, Ireland, and
| | - Eugene T Dillon
- From the UCD School of Biomolecular and Biomedical Science, UCD Conway Institute and
| | - Patrick J Guiry
- UCD School of Chemistry, UCD Centre for Synthesis and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Gerard Cagney
- From the UCD School of Biomolecular and Biomedical Science, UCD Conway Institute and
| | - Jacintha O'Sullivan
- Trinity Translational Medicine Institute, Department of Surgery, Trinity College Dublin, St. James's Hospital, Dublin 8, Ireland
| | - Breandán N Kennedy
- From the UCD School of Biomolecular and Biomedical Science, UCD Conway Institute and
| |
Collapse
|
10
|
Abstract
Ca
2+ oscillations, a widespread mode of cell signaling, were reported in non-excitable cells for the first time more than 25 years ago. Their fundamental mechanism, based on the periodic Ca
2+ exchange between the endoplasmic reticulum and the cytoplasm, has been well characterized. However, how the kinetics of cytosolic Ca
2+ changes are related to the extent of a physiological response remains poorly understood. Here, we review data suggesting that the downstream targets of Ca
2+ are controlled not only by the frequency of Ca
2+ oscillations but also by the detailed characteristics of the oscillations, such as their duration, shape, or baseline level. Involvement of non-endoplasmic reticulum Ca
2+ stores, mainly mitochondria and the extracellular medium, participates in this fine tuning of Ca
2+ oscillations. The main characteristics of the Ca
2+ exchange fluxes with these compartments are also reviewed.
Collapse
Affiliation(s)
- Geneviève Dupont
- Unité de Chronobiologie Théorique, Faculté des Sciences, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Laurent Combettes
- Interactions Cellulaires et Physiopathologie Hépatique, UMR-S 1174, Université Paris Sud, Orsay, France
| |
Collapse
|