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Borges VDF, Galant LS, Kanashiro A, Castanheira FVES, Monteiro VVS, Duarte DÂ, Rodrigues FC, Silva CMDS, Schneider AH, Cebinelli GCM, de Lima MHF, Viola JPDB, Cunha TM, da Costa Neto CM, Alves-Filho JCF, Pupo AS, Cunha FDQ. FK506 impairs neutrophil migration that results in increased polymicrobial sepsis susceptibility. Inflamm Res 2023; 72:203-215. [PMID: 36401631 DOI: 10.1007/s00011-022-01669-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 11/02/2022] [Accepted: 11/06/2022] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE This study aimed to investigate the effects of FK506 on experimental sepsis immunopathology. It investigated the effect of FK506 on leukocyte recruitment to the site of infection, systemic cytokine production, and organ injury in mice with sepsis. METHODS Using a murine cecal ligation and puncture (CLP) peritonitis model, the experiments were performed with wild-type (WT) mice and mice deficient in the gene Nfat1 (Nfat1-/-) in the C57BL/6 background. Animals were treated with 2.0 mg/kg of FK506, subcutaneously, 1 h before the sepsis model, twice a day (12 h/12 h). The number of bacteria colony forming units (CFU) was manually counted. The number of neutrophils in the lungs was estimated by the myeloperoxidase (MPO) assay. The expression of CXCR2 in neutrophils was determined using flow cytometry analysis. The expression of inflammatory cytokines in macrophage was determined using ELISA. The direct effect of FK506 on CXCR2 internalization was evaluated using HEK-293T cells after CXCL2 stimulation by the BRET method. RESULTS FK506 treatment potentiated the failure of neutrophil migration into the peritoneal cavity, resulting in bacteremia and an exacerbated systemic inflammatory response, which led to higher organ damage and mortality rates. Failed neutrophil migration was associated with elevated CXCL2 chemokine plasma levels and lower expression of the CXCR2 receptor on circulating neutrophils compared with non-treated CLP-induced septic mice. FK506 did not directly affect CXCL2-induced CXCR2 internalization by transfected HEK-293 cells or mice neutrophils, despite increasing CXCL2 release by LPS-treated macrophages. Finally, the CLP-induced response of Nfat1-/- mice was similar to those observed in the Nfat1+/+ genotype, suggesting that the FK506 effect is not dependent on the NFAT1 pathway. CONCLUSION Our data indicate that the increased susceptibility to infection of FK506-treated mice is associated with failed neutrophil migration due to the reduced membrane availability of CXCR2 receptors in response to exacerbated levels of circulating CXCL2.
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Affiliation(s)
- Vanessa de Fátima Borges
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Leticia Selinger Galant
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Alexandre Kanashiro
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Fernanda Vargas E Silva Castanheira
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Valter Vinícius Silva Monteiro
- Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Diego Ângelo Duarte
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Filipe Camargo Rodrigues
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Camila Meirelles de Souza Silva
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Ayda Henriques Schneider
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Guilherme Cesar Martelossi Cebinelli
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Mikhael Haruo Fernandes de Lima
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | | | - Thiago Mattar Cunha
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Claudio Miguel da Costa Neto
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - José Carlos Farias Alves-Filho
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - André Sampaio Pupo
- Department of Biophysics and Pharmacology, Institute of Biosciences, University of São Paulo State (UNESP), Botucatu, São Paulo, Brazil
| | - Fernando de Queiroz Cunha
- Department of Pharmacology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil. .,Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.
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Kobayashi T, Kurebayashi N, Murayama T. The Ryanodine Receptor as a Sensor for Intracellular Environments in Muscles. Int J Mol Sci 2021; 22:ijms221910795. [PMID: 34639137 PMCID: PMC8509754 DOI: 10.3390/ijms221910795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/02/2021] [Accepted: 10/04/2021] [Indexed: 01/12/2023] Open
Abstract
The ryanodine receptor (RyR) is a Ca2+ release channel in the sarcoplasmic reticulum of skeletal and cardiac muscles and plays a key role in excitation-contraction coupling. The activity of the RyR is regulated by the changes in the level of many intracellular factors, such as divalent cations (Ca2+ and Mg2+), nucleotides, associated proteins, and reactive oxygen species. Since these intracellular factors change depending on the condition of the muscle, e.g., exercise, fatigue, or disease states, the RyR channel activity will be altered accordingly. In this review, we describe how the RyR channel is regulated under various conditions and discuss the possibility that the RyR acts as a sensor for changes in the intracellular environments in muscles.
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Buckley C, Wilson C, McCarron JG. FK506 regulates Ca 2+ release evoked by inositol 1,4,5-trisphosphate independently of FK-binding protein in endothelial cells. Br J Pharmacol 2020; 177:1131-1149. [PMID: 31705533 PMCID: PMC7042112 DOI: 10.1111/bph.14905] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 12/16/2022] Open
Abstract
Background and Purpose FK506 and rapamycin are modulators of FK‐binding proteins (FKBP) that are used to suppress immune function after organ and hematopoietic stem cell transplantations. The drugs share the unwanted side‐effect of evoking hypertension that is associated with reduced endothelial function and nitric oxide production. The underlying mechanisms are not understood. FKBP may regulate IP3 receptors (IP3R) and ryanodine receptors (RyR) to alter Ca2+ signalling in endothelial cells. Experimental Approach We investigated the effects of FK506 and rapamycin on Ca2+ release via IP3R and RyR in hundreds of endothelial cells, using the indicator Cal‐520, in intact mesenteric arteries from male Sprague‐Dawley rats. IP3Rs were activated by acetylcholine or localised photo‐uncaging of IP3, and RyR by caffeine. Key Results While FKBPs were present, FKBP modulation with rapamycin did not alter IP3‐evoked Ca2+ release. Conversely, FK506, which modulates FKBP and blocks calcineurin, increased IP3‐evoked Ca2+ release. Inhibition of calcineurin (okadiac acid or cypermethrin) also increased IP3‐evoked Ca2+ release and blocked FK506 effects. When calcineurin was inhibited, FK506 reduced IP3‐evoked Ca2+ release. These findings suggest that IP3‐evoked Ca2+ release is not modulated by FKBP, but by FK506‐mediated calcineurin inhibition. The RyR modulators caffeine and ryanodine failed to alter Ca2+ signalling suggesting that RyR is not functional in native endothelium. Conclusion and Implications The hypertensive effects of the immunosuppressant drugs FK506 and rapamycin, while mediated by endothelial cells, do not appear to be exerted at the documented cellular targets of Ca2+ release and altered FKBP binding to IP3 and RyR.
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Affiliation(s)
- Charlotte Buckley
- Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, UK
| | - Calum Wilson
- Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, UK
| | - John G McCarron
- Strathclyde Institute of Pharmacy and Biomedical Science, University of Strathclyde, Glasgow, UK
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4
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 212] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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Falloon K, Juvvadi PR, Richards AD, Vargas-Muñiz JM, Renshaw H, Steinbach WJ. Characterization of the FKBP12-Encoding Genes in Aspergillus fumigatus. PLoS One 2015; 10:e0137869. [PMID: 26366742 PMCID: PMC4569257 DOI: 10.1371/journal.pone.0137869] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/22/2015] [Indexed: 01/11/2023] Open
Abstract
Invasive aspergillosis, largely caused by Aspergillus fumigatus, is responsible for a growing number of deaths among immunosuppressed patients. Immunosuppressants such as FK506 (tacrolimus) that target calcineurin have shown promise for antifungal drug development. FK506-binding proteins (FKBPs) form a complex with calcineurin in the presence of FK506 (FKBP12-FK506) and inhibit calcineurin activity. Research on FKBPs in fungi is limited, and none of the FKBPs have been previously characterized in A. fumigatus. We identified four orthologous genes of FKBP12, the human FK506 binding partner, in A. fumigatus and designated them fkbp12-1, fkbp12-2, fkbp12-3, and fkbp12-4. Deletional analysis of the four genes revealed that the Δfkbp12-1 strain was resistant to FK506, indicating FKBP12-1 as the key mediator of FK506-binding to calcineurin. The endogenously expressed FKBP12-1-EGFP fusion protein localized to the cytoplasm and nuclei under normal growth conditions but also to the hyphal septa following FK506 treatment, revealing its interaction with calcineurin. The FKBP12-1-EGFP fusion protein didn’t localize at the septa in the presence of FK506 in the cnaA deletion background, confirming its interaction with calcineurin. Testing of all deletion strains in the Galleria mellonella model of aspergillosis suggested that these proteins don’t play an important role in virulence. While the Δfkbp12-2 and Δfkbp12-3 strains didn’t show any discernable phenotype, the Δfkbp12-4 strain displayed slight growth defect under normal growth conditions and inhibition of the caspofungin-mediated “paradoxical growth effect” at higher concentrations of the antifungal caspofungin. Together, these results indicate that while only FKBP12-1 is the bona fide binding partner of FK506, leading to the inhibition of calcineurin in A. fumigatus, FKBP12-4 may play a role in basal growth and the caspofungin-mediated paradoxical growth response. Exploitation of differences between A. fumigatus FKBP12-1 and human FKBP12 will be critical for the generation of fungal-specific FK506 analogs to inhibit fungal calcineurin and treat invasive fungal disease.
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Affiliation(s)
- Katie Falloon
- Duke University School of Medicine, Durham, NC, United States of America
| | - Praveen R. Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC, United States of America
| | - Amber D. Richards
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC, United States of America
| | - José M. Vargas-Muñiz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States of America
| | - Hilary Renshaw
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States of America
| | - William J. Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC, United States of America
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States of America
- * E-mail:
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Morita T, Okada M, Yamawaki H. Mechanisms underlying a decrease in KCl-induced contraction after long-term serum-free organ culture of rat isolated mesenteric artery. J Vet Med Sci 2014; 76:963-9. [PMID: 24694942 PMCID: PMC4143657 DOI: 10.1292/jvms.14-0022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Organ culture of blood vessel
is a better technique to investigate the long-term effects of drugs. However, some
functional changes may occur from freshly isolated vessel (Fresh). Mammalian/mechanistic
target of rapamycin (mTOR) regulates smooth muscle differentiation and Ca2+
mobilization. We thus investigated mechanisms of alteration in smooth muscle contractility
after serum-free organ culture focusing on mTOR. Rat isolated mesenteric arteries were
cultured for 5 days without (0% serum) or with rapamycin. In 0% serum, absolute
contraction by KCl significantly decreased from Fresh, which was significantly rescued by
rapamycin. In 0% serum, mTOR expression significantly increased from Fresh, which was
significantly rescued by rapamycin. In 0% serum, expression of myocardin, a key regulator
of smooth muscle differentiation markers, significantly decreased from Fresh, which was
significantly rescued by rapamycin. However, the decrease in expression of contractile
proteins, including SM22α and calponin, was not changed by rapamycin. Basal
phosphorylation of calmodulin-dependent protein kinase II significantly increased in 0%
serum, which was significantly rescued by rapamycin. In 0% serum, absolute contraction by
caffeine significantly decreased from Fresh, which was significantly rescued by rapamycin.
In conclusion, expression of mTOR increased during serum-free organ culture of rat
isolated mesenteric artery for 5 days, which may be at least partly responsible for the
decreased smooth muscle contractility perhaps due to the decrease in the stored
Ca2+ in smooth muscle.
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Affiliation(s)
- Tomoka Morita
- Laboratory of Veterinary Pharmacology, School of Veterinary Medicine, Kitasato University, Aomori 034-8628, Japan
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Martín-Cano FE, Camello-Almaraz C, Hernandez D, Pozo MJ, Camello PJ. mTOR pathway and Ca²⁺ stores mobilization in aged smooth muscle cells. Aging (Albany NY) 2013; 5:339-46. [PMID: 23661091 PMCID: PMC3701109 DOI: 10.18632/aging.100555] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aging is considered to be driven by the so called senescence pathways, especially the mTOR route, although there is almost no information on its activity in aged tissues. Aging also induces Ca2+ signal alterations, but information regarding the mechanisms for these changes is almost inexistent. We investigated the possible involvement of the mTOR pathway in the age-dependent changes on Ca2+ stores mobilization in colonic smooth muscle cells of young (4 month old) and aged (24 month old) guinea pigs. mTORC1 activity was enhanced in aged smooth muscle, as revealed by phosphorylation of mTOR and its direct substrates S6K1 and 4E-BP1. Mobilization of intracellular Ca2+ stores through IP3R or RyR channels was impaired in aged cells, and it was facilitated by mTOR and by FKBP12, as indicated by the inhibitory effects of KU0063794 (a direct mTOR inhibitor), rapamycin (a FKBP12-mediated mTOR inhibitor) and FK506 (an FKBP12 binding immunosuppressant). Aging suppressed the facilitation of the Ca2+ mobilization by FKBP12 but not by mTOR, without changing the total expression of FKBP12 protein. In conclusion, or study shows that in smooth muscle aging enhances the constitutive activity of mTORC1 pathway and impairs Ca2+ stores mobilization by suppression of the FKBP12-induced facilitation of Ca2+ release.
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Affiliation(s)
- Francisco E Martín-Cano
- Department of Physiology, Faculty of Nursing and Faculty of Veterinary Sciences, University of Extremadura, 10003 Cáceres, Spain
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8
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FK506 binding proteins: Cellular regulators of intracellular Ca2+ signalling. Eur J Pharmacol 2013; 700:181-93. [DOI: 10.1016/j.ejphar.2012.12.029] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 12/04/2012] [Accepted: 12/18/2012] [Indexed: 02/04/2023]
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Tykocki NR, Thompson JM, Jackson WF, Watts SW. Ryanodine receptors are uncoupled from contraction in rat vena cava. Cell Calcium 2012. [PMID: 23177664 DOI: 10.1016/j.ceca.2012.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Ryanodine receptors (RyR) are Ca(2+)-sensitive ion channels in the sarcoplasmic reticulum (SR) membrane, and are important effectors of SR Ca(2+) release and smooth muscle excitation-contraction coupling. While the relationship between RyR activation and contraction is well characterized in arteries, little is known about the role of RyR in excitation-contraction coupling in veins. We hypothesized that RyR are present and directly coupled to contraction in rat aorta (RA) and vena cava (RVC). RA and RVC expressed mRNA for all 3 RyR subtypes, and immunofluorescence showed RyR protein was present in RA and RVC smooth muscle cells. RA and RVC rings contracted when Ca(2+) was re-introduced after stores depletion with thapsigargin (1μM), indicating both tissues contained intracellular Ca(2+) stores. To assess RyR function, contraction was then measured in RA and RVC exposed to the RyR activator caffeine (20mM). In RA, caffeine caused contraction that was attenuated by the RyR antagonists ryanodine (10μM) and tetracaine (100μM). However, caffeine (20mM) did not contract RVC. We next measured contraction and intracellular Ca(2+) (Ca(2+)(i)) simultaneously in RA and RVC exposed to caffeine. While caffeine increased Ca(2+)(i) and contracted RA, it had no significant effect on Ca(2+)(i) or contraction in RVC. These data suggest that ryanodine receptors, while present in both RA and RVC, are inactive and uncoupled from Ca(2+) release and contraction in RVC.
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Affiliation(s)
- N R Tykocki
- Department of Pharmacology and Toxicology, Michigan State University, 1355 Bogue St. Room B-445, East Lansing, MI 48824, USA.
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Narayanan D, Adebiyi A, Jaggar JH. Inositol trisphosphate receptors in smooth muscle cells. Am J Physiol Heart Circ Physiol 2012; 302:H2190-210. [PMID: 22447942 DOI: 10.1152/ajpheart.01146.2011] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Inositol 1,4,5-trisphosphate receptors (IP(3)Rs) are a family of tetrameric intracellular calcium (Ca(2+)) release channels that are located on the sarcoplasmic reticulum (SR) membrane of virtually all mammalian cell types, including smooth muscle cells (SMC). Here, we have reviewed literature investigating IP(3)R expression, cellular localization, tissue distribution, activity regulation, communication with ion channels and organelles, generation of Ca(2+) signals, modulation of physiological functions, and alterations in pathologies in SMCs. Three IP(3)R isoforms have been identified, with relative expression and cellular localization of each contributing to signaling differences in diverse SMC types. Several endogenous ligands, kinases, proteins, and other modulators control SMC IP(3)R channel activity. SMC IP(3)Rs communicate with nearby ryanodine-sensitive Ca(2+) channels and mitochondria to influence SR Ca(2+) release and reactive oxygen species generation. IP(3)R-mediated Ca(2+) release can stimulate plasma membrane-localized channels, including transient receptor potential (TRP) channels and store-operated Ca(2+) channels. SMC IP(3)Rs also signal to other proteins via SR Ca(2+) release-independent mechanisms through physical coupling to TRP channels and local communication with large-conductance Ca(2+)-activated potassium channels. IP(3)R-mediated Ca(2+) release generates a wide variety of intracellular Ca(2+) signals, which vary with respect to frequency, amplitude, spatial, and temporal properties. IP(3)R signaling controls multiple SMC functions, including contraction, gene expression, migration, and proliferation. IP(3)R expression and cellular signaling are altered in several SMC diseases, notably asthma, atherosclerosis, diabetes, and hypertension. In summary, IP(3)R-mediated pathways control diverse SMC physiological functions, with pathological alterations in IP(3)R signaling contributing to disease.
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Affiliation(s)
- Damodaran Narayanan
- Department of Physiology, University of Tennessee Health Science Center, Memphis, 38163, USA
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Macmillan D, McCarron JG. The phospholipase C inhibitor U-73122 inhibits Ca(2+) release from the intracellular sarcoplasmic reticulum Ca(2+) store by inhibiting Ca(2+) pumps in smooth muscle. Br J Pharmacol 2010; 160:1295-301. [PMID: 20590621 DOI: 10.1111/j.1476-5381.2010.00771.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The sarcoplasmic reticulum (SR) releases Ca(2+) via inositol 1,4,5-trisphosphate receptors (IP(3)R) in response to IP(3)-generating agonists. Ca(2+) release subsequently propagates as Ca(2+) waves. To clarify the role of IP(3) production in wave generation, the contribution of a key enzyme in the production of IP(3) was examined using a phosphoinositide-specific phospholipase C (PI-PLC) inhibitor, U-73122. EXPERIMENTAL APPROACH Single colonic myocytes were voltage-clamped in whole-cell configuration and cytosolic Ca(2+) concentration ([Ca(2+)](cyto)) measured using fluo-3. SR Ca(2+) release was evoked either by activation of IP(3)Rs (by carbachol or photolysis of caged IP(3)) or ryanodine receptors (RyRs; by caffeine). KEY RESULTS U-73122 inhibited carbachol-evoked [Ca(2+)](cyto) transients. The drug also inhibited [Ca(2+)](cyto) increases, evoked by direct IP(3)R activation (by photolysis of caged IP(3)) and RyR activation (by caffeine), which do not require PI-PLC activation. U-73122 also increased steady-state [Ca(2+)](cyto) and slowed the rate of Ca(2+) removal from the cytoplasm. An inactive analogue of U-73122, U-73343, was without effect on either IP(3)R- or RyR-mediated Ca(2+) release. CONCLUSIONS AND IMPLICATIONS U-73122 inhibited carbachol-evoked [Ca(2+)](cyto) increases. However, the drug also reduced Ca(2+) release when evoked by direct activation of IP(3)R or RyR, slowed Ca(2+) removal and increased steady-state [Ca(2+)](cyto). These results suggest U-73122 reduces IP(3)-evoked Ca(2+) transients by inhibiting the SR Ca(2+) pump to deplete the SR of Ca(2+) rather than by inhibiting PI-PLC.
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Affiliation(s)
- D Macmillan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK.
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12
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MacMillan D, McCarron JG. Regulation by FK506 and rapamycin of Ca2+ release from the sarcoplasmic reticulum in vascular smooth muscle: the role of FK506 binding proteins and mTOR. Br J Pharmacol 2009; 158:1112-20. [PMID: 19785652 DOI: 10.1111/j.1476-5381.2009.00369.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND AND PURPOSE The sarcoplasmic reticulum (SR), regulates the cytoplasmic Ca(2+) concentration ([Ca(2+)](cyto)) in vascular smooth muscle. Release from the SR is controlled by two intracellular receptor/channel complexes, the ryanodine receptor (RyR) and the inositol 1,4,5-trisphosphate receptor (IP(3)R). These receptors may be regulated by the accessory FK506-binding protein (FKBP) either directly, by binding to the channel, or indirectly via FKBP modulation of two targets, the phosphatase, calcineurin or the kinase, mammalian target of rapamycin (mTOR). EXPERIMENTAL APPROACH Single portal vein myocytes were voltage-clamped in whole cell configuration and [Ca(2+)](cyto) measured using fluo-3. IP(3)Rs were activated by photolysis of caged IP(3) and RyRs activated by hydrostatic application of caffeine. KEY RESULTS FK506 which displaces FKBP from each receptor (to inhibit calcineurin) increased the [Ca(2+)](cyto) rise evoked by activation of either RyR or IP(3)R. Rapamycin which displaces FKBP (to inhibit mTOR) also increased the amplitude of the caffeine-evoked, but reduced the IP(3)-evoked [Ca(2+)](cyto) rise. None of the phosphatase inhibitors, cypermethrin, okadaic acid or calcineurin inhibitory peptide, altered either caffeine- or IP(3)-evoked [Ca(2+)](cyto) release; calcineurin did not contribute to FK506-mediated potentiation of RyR- or IP(3)R-mediated Ca(2+) release. The mTOR inhibitor LY294002, like rapamycin, decreased IP(3)-evoked Ca(2+) release. CONCLUSIONS AND IMPLICATIONS Ca(2+) release in portal vein myocytes, via RyR, was modulated directly by FKBP binding to the channel; neither calcineurin nor mTOR contributed to this regulation. However, IP(3)R-mediated Ca(2+) release, while also modulated directly by FKBP may be additionally regulated by mTOR. Rapamycin inhibition of IP(3)-mediated Ca(2+) release may be explained by mTOR inhibition.
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Affiliation(s)
- D MacMillan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
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