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Han Z, Ge L, Wen S, Sun J. Dysfunction of the intestinal physical barrier in the intestinal inflammation of tongue sole, Cynoglossus semilaevis, induced by Shewanella algae infection. FISH & SHELLFISH IMMUNOLOGY 2023:108900. [PMID: 37315911 DOI: 10.1016/j.fsi.2023.108900] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 06/10/2023] [Accepted: 06/12/2023] [Indexed: 06/16/2023]
Abstract
Bacterial intestinal inflammation occurs frequently in cultured fish. However, research on the dysfunction of the intestinal physical barrier in fish intestinal inflammation is scarce. In this study, intestinal inflammation in tongue sole Cynoglossus semilaevis was induced by Shewanella algae and the intestinal permeability was investigated. Gene expression patterns in inflammatory factors, tight junction molecules, and keratins 8 and 18 in the intestines were further explored. Histological examinations of the middle intestines showed that S. algae induced pathological lesions of intestinal inflammation and significantly increased the total number of mucous cells (p < 0.01). Ultrastructural observation in the middle intestines showed that intercellular spaces between epithelial cells were significantly wider in infected fish compared with the control (p < 0.01). The positive result of fluorescence in situ hybridization confirmed the presence of S. algae in the intestine. Enhanced Evans blue exudation and increased levels of serum d-lactate and intestinal fatty acid binding protein were suggestive of increased intestinal barrier permeability. The mRNA levels of four pro-inflammatory cytokines, namely IL-6, IL-8, IL-β, and TNF-α, were significantly increased after S. algae infection at most tested time points (p < 0.01 or p < 0.05), while there was an alternating increasing and decreasing trend in the gene expression patterns of IL-10, TGF-β, TLR-2, AP-1, and CASP-1. The mRNA expression of tight junction molecules (claudin-1, claudin-2, ZO-1, JAM-A, and MarvelD3) and keratins 8 and 18 in the intestines was significantly decreased at 6, 12, 24, 48, or 72 h post infection (p < 0.01 or p < 0.05). In conclusion, S. algae infection induced intestinal inflammation accompanied by increased intestinal permeability in tongue sole, and tight junction molecules and keratins were probably associated with the pathological process.
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Affiliation(s)
- Zhuoran Han
- Tianjin Key Lab of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China.
| | - Lunhua Ge
- Tianjin Key Lab of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China.
| | - Siyi Wen
- Tianjin Key Lab of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China.
| | - Jingfeng Sun
- Tianjin Key Lab of Aqua-ecology and Aquaculture, Fisheries College, Tianjin Agricultural University, Tianjin, 300384, China.
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2
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Solár P, Zamani A, Lakatosová K, Joukal M. The blood-brain barrier and the neurovascular unit in subarachnoid hemorrhage: molecular events and potential treatments. Fluids Barriers CNS 2022; 19:29. [PMID: 35410231 PMCID: PMC8996682 DOI: 10.1186/s12987-022-00312-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/24/2022] [Indexed: 12/12/2022] Open
Abstract
The response of the blood-brain barrier (BBB) following a stroke, including subarachnoid hemorrhage (SAH), has been studied extensively. The main components of this reaction are endothelial cells, pericytes, and astrocytes that affect microglia, neurons, and vascular smooth muscle cells. SAH induces alterations in individual BBB cells, leading to brain homeostasis disruption. Recent experiments have uncovered many pathophysiological cascades affecting the BBB following SAH. Targeting some of these pathways is important for restoring brain function following SAH. BBB injury occurs immediately after SAH and has long-lasting consequences, but most changes in the pathophysiological cascades occur in the first few days following SAH. These changes determine the development of early brain injury as well as delayed cerebral ischemia. SAH-induced neuroprotection also plays an important role and weakens the negative impact of SAH. Supporting some of these beneficial cascades while attenuating the major pathophysiological pathways might be decisive in inhibiting the negative impact of bleeding in the subarachnoid space. In this review, we attempt a comprehensive overview of the current knowledge on the molecular and cellular changes in the BBB following SAH and their possible modulation by various drugs and substances.
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Affiliation(s)
- Peter Solár
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
- Department of Neurosurgery, Faculty of Medicine, Masaryk University and St. Anne's University Hospital Brno, Pekařská 53, 656 91, Brno, Czech Republic
| | - Alemeh Zamani
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
| | - Klaudia Lakatosová
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic
| | - Marek Joukal
- Department of Anatomy, Cellular and Molecular Neurobiology Research Group, Faculty of Medicine, Masaryk University, 625 00, Brno, Czech Republic.
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3
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Ma X, Liu W. Calcium signaling in brain microvascular endothelial cells and its roles in the function of the blood-brain barrier. Neuroreport 2020; 30:1271-1277. [PMID: 31688421 DOI: 10.1097/wnr.0000000000001357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The blood-brain barrier (BBB) plays critical roles in maintaining the stability of the brain's internal milieu, providing nutrients for the brain, and preventing toxic materials from the blood from entering the brain. The cellular structure of the BBB is mainly composed of brain microvascular endothelial cells (BMVECs), which are surrounded by astrocytic endfeet that are connected by tight junction proteins, pericytes and astrocytes. Recently, several studies have shown that aberrant increase in intracellular calcium levels in BMVECs lead to cellular metabolic disturbances and subsequent impairment of BBB integrity. Although multiple stresses can lead to intracellular calcium accumulation, inherent protective mechanisms in affected cells are subsequently activated to maintain calcium homeostasis. However, once the increase in intracellular calcium goes beyond a certain threshold, disturbances in cellular structures, protein expression, and the BBB permeability are inevitable. Here, we review recent research on the different factors regulating intracellular calcium concentrations and the mechanisms related to how calcium signaling cascades protect the BMVECs from outside injury. We also consider the potential of calcium signaling regulators as therapeutic targets for modulating intracellular calcium homeostasis and ameliorating BBB disruption in patients with calcium-related pathologies.
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Affiliation(s)
- Xingjie Ma
- Department of Intensive Care, The Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
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4
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Mir B, Goettsch C. Extracellular Vesicles as Delivery Vehicles of Specific Cellular Cargo. Cells 2020; 9:cells9071601. [PMID: 32630649 PMCID: PMC7407641 DOI: 10.3390/cells9071601] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/29/2020] [Accepted: 06/30/2020] [Indexed: 02/06/2023] Open
Abstract
Extracellular vesicles (EVs) mediate cell-to-cell communication via the transfer of biomolecules locally and systemically between organs. It has been elucidated that the specific EV cargo load is fundamental for cellular response upon EV delivery. Therefore, revealing the specific molecular machinery that functionally regulates the precise EV cargo intracellularly is of importance in understanding the role of EVs in physiology and pathophysiology and conveying therapeutic use. The purpose of this review is to summarize recent findings on the general rules, as well as specific modulator motifs governing EV cargo loading. Finally, we address available information on potential therapeutic strategies to alter cargo loading.
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Berra-Romani R, Guzmán-Silva A, Vargaz-Guadarrama A, Flores-Alonso JC, Alonso-Romero J, Treviño S, Sánchez-Gómez J, Coyotl-Santiago N, García-Carrasco M, Moccia F. Type 2 Diabetes Alters Intracellular Ca 2+ Handling in Native Endothelium of Excised Rat Aorta. Int J Mol Sci 2019; 21:ijms21010250. [PMID: 31905880 PMCID: PMC6982087 DOI: 10.3390/ijms21010250] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 12/24/2019] [Accepted: 12/25/2019] [Indexed: 02/03/2023] Open
Abstract
An increase in intracellular Ca2+ concentration ([Ca2+]i) plays a key role in controlling endothelial functions; however, it is still unclear whether endothelial Ca2+ handling is altered by type 2 diabetes mellitus, which results in severe endothelial dysfunction. Herein, we analyzed for the first time the Ca2+ response to the physiological autacoid ATP in native aortic endothelium of obese Zucker diabetic fatty (OZDF) rats and their lean controls, which are termed LZDF rats. By loading the endothelial monolayer with the Ca2+-sensitive fluorophore, Fura-2/AM, we found that the endothelial Ca2+ response to 20 µM and 300 µM ATP exhibited a higher plateau, a larger area under the curve and prolonged duration in OZDF rats. The “Ca2+ add-back” protocol revealed no difference in the inositol-1,4,5-trisphosphate-releasable endoplasmic reticulum (ER) Ca2+ pool, while store-operated Ca2+ entry was surprisingly down-regulated in OZDF aortae. Pharmacological manipulation disclosed that sarco-endoplasmic reticulum Ca2+-ATPase (SERCA) activity was down-regulated by reactive oxygen species in native aortic endothelium of OZDF rats, thereby exaggerating the Ca2+ response to high agonist concentrations. These findings shed new light on the mechanisms by which type 2 diabetes mellitus may cause endothelial dysfunction by remodeling the intracellular Ca2+ toolkit.
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Affiliation(s)
- Roberto Berra-Romani
- Laboratory of Cardiovascular Physiology, Biomedicine School, Faculty of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico; (A.G.-S.); (J.A.-R.); (N.C.-S.)
- Correspondence: (R.B.-R.); (F.M.)
| | - Alejandro Guzmán-Silva
- Laboratory of Cardiovascular Physiology, Biomedicine School, Faculty of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico; (A.G.-S.); (J.A.-R.); (N.C.-S.)
| | - Ajelet Vargaz-Guadarrama
- Faculty of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico; (A.V.-G.); (J.S.-G.); (M.G.-C.)
| | - Juan Carlos Flores-Alonso
- Centro de Investigación Biomédica de Oriente, Instituto Mexicano del Seguro Social, Puebla 74360, Mexico;
| | - José Alonso-Romero
- Laboratory of Cardiovascular Physiology, Biomedicine School, Faculty of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico; (A.G.-S.); (J.A.-R.); (N.C.-S.)
| | - Samuel Treviño
- Facultad de Ciencias Químicas, Benemérita Universidad Autónoma de Puebla, Puebla 72540, Mexico;
| | - Josué Sánchez-Gómez
- Faculty of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico; (A.V.-G.); (J.S.-G.); (M.G.-C.)
| | - Nayeli Coyotl-Santiago
- Laboratory of Cardiovascular Physiology, Biomedicine School, Faculty of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico; (A.G.-S.); (J.A.-R.); (N.C.-S.)
| | - Mario García-Carrasco
- Faculty of Medicine, Benemérita Universidad Autónoma de Puebla, Puebla 72410, Mexico; (A.V.-G.); (J.S.-G.); (M.G.-C.)
| | - Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology “Lazzaro Spallanzani”, University of Pavia, 27100 Pavia, Italy
- Correspondence: (R.B.-R.); (F.M.)
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6
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Svab G, Doczi J, Gerencser AA, Ambrus A, Gallyas F, Sümegi B, Tretter L. The Mitochondrial Targets of Neuroprotective Drug Vinpocetine on Primary Neuron Cultures, Brain Capillary Endothelial Cells, Synaptosomes, and Brain Mitochondria. Neurochem Res 2019; 44:2435-2447. [PMID: 31535355 PMCID: PMC6776483 DOI: 10.1007/s11064-019-02871-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 08/29/2019] [Accepted: 09/05/2019] [Indexed: 12/13/2022]
Abstract
Vinpocetine is considered as neuroprotectant drug and used for treatment of brain ischemia and cognitive deficiencies for decades. A number of enzymes, channels and receptors can bind vinpocetine, however the mechanisms of many effects' are still not clear. The present study investigated the effects of vinpocetine from the mitochondrial bioenergetic aspects. In primary brain capillary endothelial cells the purinergic receptor-stimulated mitochondrial Ca2+ uptake and efflux were studied. Vinpocetine exerted a partial inhibition on the mitochondrial calcium efflux. In rodent brain synaptosomes vinpocetine (30 μM) inhibited respiration in uncoupler stimulated synaptosomes and decreased H2O2 release from the nerve terminals in resting and in complex I inhibited conditions, respectively. In isolated rat brain mitochondria using either complex I or complex II substrates leak respiration was stimulated, but ADP-induced respiration was inhibited by vinpocetine. The stimulation of oxidation was associated with a small extent of membrane depolarization. Mitochondrial H2O2 production was inhibited by vinpocetine under all conditions investigated. The most pronounced effects were detected with the complex II substrate succinate. Vinpocetine also mitigated both Ca2+-induced mitochondrial Ca2+-release and Ca2+-induced mitochondrial swelling. It lowered the rate of mitochondrial ATP synthesis, while increasing ATPase activity. These results indicate more than a single mitochondrial target of this vinca alkaloid. The relevance of the affected mitochondrial mechanisms in the anti ischemic effect of vinpocetine is discussed.
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Affiliation(s)
- Gergely Svab
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 37-47 Tuzolto Street, Budapest, 1094, Hungary
| | - Judit Doczi
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 37-47 Tuzolto Street, Budapest, 1094, Hungary
| | - Akos A Gerencser
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 37-47 Tuzolto Street, Budapest, 1094, Hungary.,Buck Institute for Research on Aging, Novato, CA, USA
| | - Attila Ambrus
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 37-47 Tuzolto Street, Budapest, 1094, Hungary
| | - Ferenc Gallyas
- Department of Biochemistry and Medical Chemistry, University of Pecs Medical School, Pecs, Hungary.,Szentagothai Research Centre, University of Pecs, Pecs, Hungary.,Nuclear-Mitochondrial Interactions Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Balazs Sümegi
- Department of Biochemistry and Medical Chemistry, University of Pecs Medical School, Pecs, Hungary.,Szentagothai Research Centre, University of Pecs, Pecs, Hungary.,Nuclear-Mitochondrial Interactions Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - László Tretter
- Department of Medical Biochemistry, MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, 37-47 Tuzolto Street, Budapest, 1094, Hungary.
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7
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Shyong YJ, Chang KC, Lin FH. Calcium phosphate particles stimulate exosome secretion from phagocytes for the enhancement of drug delivery. Colloids Surf B Biointerfaces 2018; 171:391-397. [PMID: 30064087 DOI: 10.1016/j.colsurfb.2018.07.037] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/27/2018] [Accepted: 07/18/2018] [Indexed: 01/08/2023]
Abstract
Exosomes are attractive potential carriers for drug delivery because of their natural function of transferring biomolecules among cells without eliciting immune responses. However, an obstacle to the application of exosomes for drug delivery is the difficulty in collecting sufficient numbers of these vesicles. In this study, we demonstrate treatment with calcium phosphate (CaP) particles could increase over two-fold the number of exosomes secreted from macrophage-like RAW264.7 cells and monocyte-like THP-1 cells. CaP particles were easily internalized into cells and dissolved in acidic late-endosomes or lysosomes, resulting in the rupture of their membranes followed by the release of Ca2+ into cytosol. Moreover, we found that exosomes secreted from cells treated with CaP particles are not contaminated by the Ca2+ released from CaP; the Ca2+ contents in exosomes secreted from CaP particle-treated cells were similar to that in exosomes from untreated control cells. This study highlights the potential for the efficient production of exosomes using CaP particles for drug delivery.
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Affiliation(s)
- Yan-Jye Shyong
- Institute of Biomedical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan; Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, 92093, United States
| | - Kuo-Chi Chang
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao E. Road, Taipei, 10608, Taiwan
| | - Feng-Huei Lin
- Institute of Biomedical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan; Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, No. 35, Keyan Road, Zhunan Town, Miaoli County, 35053, Taiwan.
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8
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Guerra G, Lucariello A, Perna A, Botta L, De Luca A, Moccia F. The Role of Endothelial Ca 2+ Signaling in Neurovascular Coupling: A View from the Lumen. Int J Mol Sci 2018; 19:E938. [PMID: 29561829 PMCID: PMC5979341 DOI: 10.3390/ijms19040938] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/16/2018] [Accepted: 03/17/2018] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Neurovascular coupling (NVC) is the mechanism whereby an increase in neuronal activity (NA) leads to local elevation in cerebral blood flow (CBF) to match the metabolic requirements of firing neurons. Following synaptic activity, an increase in neuronal and/or astrocyte Ca2+ concentration leads to the synthesis of multiple vasoactive messengers. Curiously, the role of endothelial Ca2+ signaling in NVC has been rather neglected, although endothelial cells are known to control the vascular tone in a Ca2+-dependent manner throughout peripheral vasculature. METHODS We analyzed the literature in search of the most recent updates on the potential role of endothelial Ca2+ signaling in NVC. RESULTS We found that several neurotransmitters (i.e., glutamate and acetylcholine) and neuromodulators (e.g., ATP) can induce dilation of cerebral vessels by inducing an increase in endothelial Ca2+ concentration. This, in turn, results in nitric oxide or prostaglandin E2 release or activate intermediate and small-conductance Ca2+-activated K⁺ channels, which are responsible for endothelial-dependent hyperpolarization (EDH). In addition, brain endothelial cells express multiple transient receptor potential (TRP) channels (i.e., TRPC3, TRPV3, TRPV4, TRPA1), which induce vasodilation by activating EDH. CONCLUSIONS It is possible to conclude that endothelial Ca2+ signaling is an emerging pathway in the control of NVC.
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Affiliation(s)
- Germano Guerra
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, via F. De Santis, 86100 Campobasso, Italy.
| | - Angela Lucariello
- Department of Mental Health and Preventive Medicine, Section of Human Anatomy, University of Campania "L. Vanvitelli", 81100 Naples, Italy.
| | - Angelica Perna
- Department of Medicine and Health Sciences "Vincenzo Tiberio", University of Molise, via F. De Santis, 86100 Campobasso, Italy.
| | - Laura Botta
- Laboratory of General Physiology, Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, via Forlanini 6, 27100 Pavia, Italy.
| | - Antonio De Luca
- Department of Mental Health and Preventive Medicine, Section of Human Anatomy, University of Campania "L. Vanvitelli", 81100 Naples, Italy.
| | - Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, via Forlanini 6, 27100 Pavia, Italy.
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9
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Lillo MA, Gaete PS, Puebla M, Ardiles NM, Poblete I, Becerra A, Simon F, Figueroa XF. Critical contribution of Na +-Ca 2+ exchanger to the Ca 2+-mediated vasodilation activated in endothelial cells of resistance arteries. FASEB J 2018; 32:2137-2147. [PMID: 29217667 DOI: 10.1096/fj.201700365rr] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Na+-Ca2+ exchanger (NCX) contributes to control the intracellular free Ca2+ concentration ([Ca2+]i), but the functional activation of NCX reverse mode (NCXrm) in endothelial cells is controversial. We evaluated the participation of NCXrm-mediated Ca2+ uptake in the endothelium-dependent vasodilation of rat isolated mesenteric arterial beds. In phenylephrine-contracted mesenteries, the acetylcholine (ACh)-induced vasodilation was abolished by treatment with the NCXrm blockers SEA0400, KB-R7943, or SN-6. Consistent with that, the ACh-induced hyperpolarization observed in primary cultures of mesenteric endothelial cells and in smooth muscle of isolated mesenteric resistance arteries was attenuated by KB-R7943 and SEA0400, respectively. In addition, both blockers abolished the NO production activated by ACh in intact mesenteric arteries. In contrast, the inhibition of NCXrm did not affect the vasodilator responses induced by the Ca2+ ionophore, ionomycin, and the NO donor, S-nitroso- N-acetylpenicillamine. Furthermore, SEA0400, KB-R7943, and a small interference RNA directed against NCX1 blunted the increase in [Ca2+]i induced by ACh or ATP in cultured endothelial cells. The analysis by proximity ligation assay showed that the NO-synthesizing enzyme, eNOS, and NCX1 were associated in endothelial cell caveolae of intact mesenteric resistance arteries. These results indicate that the activation of NCXrm has a central role in Ca2+-mediated vasodilation initiated by ACh in endothelial cells of resistance arteries.-Lillo, M. A., Gaete, P. S., Puebla, M., Ardiles, N. M., Poblete, I., Becerra, A., Simon, F., Figueroa, X. F. Critical contribution of Na+-Ca2+ exchanger to the Ca2+-mediated vasodilation activated in endothelial cells of resistance arteries.
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Affiliation(s)
- Mauricio A Lillo
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pablo S Gaete
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mariela Puebla
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nicolás M Ardiles
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Inés Poblete
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alvaro Becerra
- Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas and Facultad de Medicina, Universidad Andres Bello, Santiago, Chile.,Millennium Institute on Immunology and Immunotherapy, Santiago, Chile.,Departamento de Ciencias Químicas y Biológicas, Facultad de Salud, Deporte y Recreación, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Felipe Simon
- Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas and Facultad de Medicina, Universidad Andres Bello, Santiago, Chile.,Millennium Institute on Immunology and Immunotherapy, Santiago, Chile
| | - Xavier F Figueroa
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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10
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IP 3 receptor signaling and endothelial barrier function. Cell Mol Life Sci 2017; 74:4189-4207. [PMID: 28803370 DOI: 10.1007/s00018-017-2624-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 07/18/2017] [Accepted: 08/08/2017] [Indexed: 12/14/2022]
Abstract
The endothelium, a monolayer of endothelial cells lining vessel walls, maintains tissue-fluid homeostasis by restricting the passage of the plasma proteins and blood cells into the interstitium. The ion Ca2+, a ubiquitous secondary messenger, initiates signal transduction events in endothelial cells that is critical to control of vascular tone and endothelial permeability. The ion Ca2+ is stored inside the intracellular organelles and released into the cytosol in response to environmental cues. The inositol 1,4,5-trisphosphate (IP3) messenger facilitates Ca2+ release through IP3 receptors which are Ca2+-selective intracellular channels located within the membrane of the endoplasmic reticulum. Binding of IP3 to the IP3Rs initiates assembly of IP3R clusters, a key event responsible for amplification of Ca2+ signals in endothelial cells. This review discusses emerging concepts related to architecture and dynamics of IP3R clusters, and their specific role in propagation of Ca2+ signals in endothelial cells.
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11
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Stokum JA, Gerzanich V, Simard JM. Molecular pathophysiology of cerebral edema. J Cereb Blood Flow Metab 2016; 36:513-38. [PMID: 26661240 PMCID: PMC4776312 DOI: 10.1177/0271678x15617172] [Citation(s) in RCA: 357] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/21/2015] [Accepted: 10/22/2015] [Indexed: 12/25/2022]
Abstract
Advancements in molecular biology have led to a greater understanding of the individual proteins responsible for generating cerebral edema. In large part, the study of cerebral edema is the study of maladaptive ion transport. Following acute CNS injury, cells of the neurovascular unit, particularly brain endothelial cells and astrocytes, undergo a program of pre- and post-transcriptional changes in the activity of ion channels and transporters. These changes can result in maladaptive ion transport and the generation of abnormal osmotic forces that, ultimately, manifest as cerebral edema. This review discusses past models and current knowledge regarding the molecular and cellular pathophysiology of cerebral edema.
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Affiliation(s)
- Jesse A Stokum
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA
| | - J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, USA Department of Pathology, University of Maryland School of Medicine, Baltimore, USA Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
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12
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Blood-brain barrier Na transporters in ischemic stroke. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 71:113-46. [PMID: 25307215 DOI: 10.1016/bs.apha.2014.06.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Blood-brain barrier (BBB) endothelial cells form a barrier that is highly restrictive to passage of solutes between blood and brain. Many BBB transport mechanisms have been described that mediate transcellular movement of solutes across the barrier either into or out of the brain. One class of BBB transporters that is all too often overlooked is that of the ion transporters. The BBB has a rich array of ion transporters and channels that carry Na, K, Cl, HCO3, Ca, and other ions. Many of these are asymmetrically distributed between the luminal and abluminal membranes, giving BBB endothelial cells the ability to perform vectorial transport of ions across the barrier between blood and brain. In this manner, the BBB performs the important function of regulating the volume and composition of brain interstitial fluid. Through functional coupling of luminal and abluminal transporters and channels, the BBB carries Na, Cl, and other ions from blood into brain, producing up to 30% of brain interstitial fluid in healthy brain. During ischemic stroke cerebral edema forms by processes involving increased activity of BBB luminal Na transporters, resulting in "hypersecretion" of Na, Cl, and water into the brain interstitium. This review discusses the roles of luminal BBB Na transporters in edema formation in stroke, with an emphasis on Na-K-Cl cotransport and Na/H exchange. Evidence that these transporters provide effective therapeutic targets for reduction of edema in stroke is also discussed, as are recent findings regarding signaling pathways responsible for ischemia stimulation of the BBB Na transporters.
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De Bock M, Wang N, Decrock E, Bol M, Gadicherla AK, Culot M, Cecchelli R, Bultynck G, Leybaert L. Endothelial calcium dynamics, connexin channels and blood-brain barrier function. Prog Neurobiol 2013; 108:1-20. [PMID: 23851106 DOI: 10.1016/j.pneurobio.2013.06.001] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Revised: 06/12/2013] [Accepted: 06/18/2013] [Indexed: 01/11/2023]
Abstract
Situated between the circulation and the brain, the blood-brain barrier (BBB) protects the brain from circulating toxins while securing a specialized environment for neuro-glial signaling. BBB capillary endothelial cells exhibit low transcytotic activity and a tight, junctional network that, aided by the cytoskeleton, restricts paracellular permeability. The latter is subject of extensive research as it relates to neuropathology, edema and inflammation. A key determinant in regulating paracellular permeability is the endothelial cytoplasmic Ca(2+) concentration ([Ca(2+)]i) that affects junctional and cytoskeletal proteins. Ca(2+) signals are not one-time events restricted to a single cell but often appear as oscillatory [Ca(2+)]i changes that may propagate between cells as intercellular Ca(2+) waves. The effect of Ca(2+) oscillations/waves on BBB function is largely unknown and we here review current evidence on how [Ca(2+)]i dynamics influence BBB permeability.
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Affiliation(s)
- Marijke De Bock
- Dept. of Basic Medical Sciences, Ghent University, Ghent, Belgium.
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14
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Moccia F, Berra-Romani R, Tanzi F. Update on vascular endothelial Ca 2+ signalling: A tale of ion channels, pumps and transporters. World J Biol Chem 2012; 3:127-58. [PMID: 22905291 PMCID: PMC3421132 DOI: 10.4331/wjbc.v3.i7.127] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/04/2012] [Accepted: 07/11/2012] [Indexed: 02/05/2023] Open
Abstract
A monolayer of endothelial cells (ECs) lines the lumen of blood vessels and forms a multifunctional transducing organ that mediates a plethora of cardiovascular processes. The activation of ECs from as state of quiescence is, therefore, regarded among the early events leading to the onset and progression of potentially lethal diseases, such as hypertension, myocardial infarction, brain stroke, and tumor. Intracellular Ca2+ signals have long been know to play a central role in the complex network of signaling pathways regulating the endothelial functions. Notably, recent work has outlined how any change in the pattern of expression of endothelial channels, transporters and pumps involved in the modulation of intracellular Ca2+ levels may dramatically affect whole body homeostasis. Vascular ECs may react to both mechanical and chemical stimuli by generating a variety of intracellular Ca2+ signals, ranging from brief, localized Ca2+ pulses to prolonged Ca2+ oscillations engulfing the whole cytoplasm. The well-defined spatiotemporal profile of the subcellular Ca2+ signals elicited in ECs by specific extracellular inputs depends on the interaction between Ca2+ releasing channels, which are located both on the plasma membrane and in a number of intracellular organelles, and Ca2+ removing systems. The present article aims to summarize both the past and recent literature in the field to provide a clear-cut picture of our current knowledge on the molecular nature and the role played by the components of the Ca2+ machinery in vascular ECs under both physiological and pathological conditions.
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Affiliation(s)
- Francesco Moccia
- Francesco Moccia, Franco Tanzi, Department of Biology and Biotechnologies "Lazzaro Spallanzani", Laboratory of Physiology, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
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Celotto AC, Capellini VK, Restini CBA, Baldo CF, Bendhack LM, Evora PRB. Extracellular alkalinization induces endothelium-derived nitric oxide dependent relaxation in rat thoracic aorta. Nitric Oxide 2010; 23:269-74. [PMID: 20682356 DOI: 10.1016/j.niox.2010.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2010] [Revised: 07/10/2010] [Accepted: 07/29/2010] [Indexed: 10/19/2022]
Abstract
AIM To investigate the mechanism through which the extracellular alkalinization promotes relaxation in rat thoracic aorta. METHODS The relaxation response to NaOH-induced extracellular alkalinization (7.4-8.5) was measured in aortic rings pre-contracted with phenylephrine (Phe, 10(-6) M). The vascular reactivity experiments were performed in endothelium-intact and -denuded rings, in the presence or and absence of indomethacin (10(-5) M), NG-nitro-l-arginine methyl ester (L-NAME, 10(-4) M), N-(6-Aminohexyl)-5-chloro-1-naphthalenesulfonamide/HCl (W-7, 10(-7) M), 2,5-dimethylbenzimidazole (DMB, 2×10(-5) M) and methyl-β-cyclodextrin (10(-2) M). In addition, the effects of NaOH-induced extracellular alkalinization (pH 8.0 and 8.5) on the intracellular nitric oxide (NO) concentration was evaluated in isolated endothelial cells loaded with diaminofluorescein-FM diacetate (DAF-FM DA, 5 μM), in the presence and absence of DMB (2×10(-5) M). RESULTS The extracellular alkalinization failed to induce any change in vascular tone in aortic rings pre-contracted with KCl. In rings pre-contracted with Phe, the extracellular alkalinization caused relaxation in the endothelium-intact rings only, and this relaxation was maintained after cyclooxygenase inhibition; completely abolished by the inhibition of nitric oxide synthase (NOS), Ca(2+)/calmodulin and Na(+)/Ca(2+) exchanger (NCX), and partially blunted by the caveolae disassembly. CONCLUSIONS These results suggest that, in rat thoracic aorta, that extracellular alkalinization with NaOH activates the NCX reverse mode of endothelial cells in rat thoracic aorta, thereby the intracellular Ca(2+) concentration and activating the Ca(2+)/calmodulin-dependent NOS. In turn, NO is released promoting relaxation.
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Affiliation(s)
- A C Celotto
- Laboratory of Endothelial Function, Department of Surgery and Anatomy, School of Medicine, University of São Paulo, Ribeirão Preto, SP, Brazil
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Na+-Ca2+ exchanger contributes to Ca2+ extrusion in ATP-stimulated endothelium of intact rat aorta. Biochem Biophys Res Commun 2010; 395:126-30. [PMID: 20353753 DOI: 10.1016/j.bbrc.2010.03.153] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Accepted: 03/25/2010] [Indexed: 11/20/2022]
Abstract
The role of Na(+)-Ca(2+) exchanger (NCX) in vascular endothelium is still matter of debate. Depending on both the endothelial cell (EC) type and the extracellular ligand, NCX has been shown to operate in either the forward (Ca(2+) out)- or the reverse (Ca(2+) in)-mode. In particular, acetylcholine (Ach) has been shown to promote Ca(2+) inflow in the intact endothelium of excised rat aorta. Herein, we assessed the involvement of NCX into the Ca(2+) signals elicited by ATP in such preparation. Removal of extracellular Na(+) (0Na(+)) causes the NCX to switch into the reverse-mode and induced an increase in intracellular Ca(2+) concentration ([Ca(2+)](i)), which disappeared in the absence of extracellular Ca(2+), and in the presence of benzamil, which blocks both modes of NCX, and KB-R 7943, a selective inhibitor of the reverse-mode. ATP induced a transient Ca(2+) signal, whose decay was significantly prolonged by 0Na(+), benzamil, DCB, and monensin while it was unaffected by KB-R 7943. Notably, lowering extracellular Na(+) concentration increased the sensibility to lower doses of ATP. These date suggest that, unlike Ach-stimulated ECs, NCX promotes Ca(2+) extrusion when the stimulus is provided by ATP in intact endothelium of rat aorta. These data show that, within the same preparation, NCX operates in both modes, depending on the chemical nature of the extracellular stimulus.
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Chavez-Muñoz C, Kilani RT, Ghahary A. Profile of exosomes related proteins released by differentiated and undifferentiated human keratinocytes. J Cell Physiol 2009; 221:221-31. [DOI: 10.1002/jcp.21847] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Li Y, Liu L, Li J, Xie L, Wang GJ, Liu XD. Transport of gatifloxacin involves Na+/Ca2+ exchange and excludes P-glycoprotein and multidrug resistance associated-proteins in primary cultured rat brain endothelial cells. Eur J Pharmacol 2009; 616:68-72. [PMID: 19497321 DOI: 10.1016/j.ejphar.2009.05.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Revised: 05/14/2009] [Accepted: 05/19/2009] [Indexed: 11/28/2022]
Abstract
The characteristics of gatifloxacin transport across blood brain barrier were investigated using primary cultured rat brain microvessel endothelial cells (rBMECs) as an in vitro model. Gatifloxacin uptake by rBMECs was time-, temperature- and energy-dependent. Gatifloxacin uptake by rBMECs was not influenced by P-glycoprotein (P-GP) inhibitor cyclosporine A or multidrug resistance associated-proteins (MRPs) inhibitor probenecid. However, verapamil inhibited the uptake in a concentration-dependent manner. Transendothelial transport study showed that transport of gatifloxacin across rBMEC monolayer was bidirectional, verapamil concentration-dependently inhibited transport from the apical to basolateral side, but did not significantly affect transport from basolateral to apical side. Gatifloxacin uptake was decreased in Ca(2+)-deprived medium but increased in Mg(2+)-deprived medium significantly. Furthermore, organic Ca(2+) channel blockers nifedipine and diltiazem had no effect on gatifloxacin uptake, but inorganic Ca(2+) channel blockers Ni(2+) and Mg(2+) inhibited the gatifloxacin uptake. The present study suggests that gatifloxacin transport across rBMECs involves a Na(+)/Ca(2+) exchange mechanism and extracellular Ca(2+) but not P-GP and MRPs.
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Affiliation(s)
- Yang Li
- Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, Jiangsu, PR China
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Brown RC, Wu L, Hicks K, O'neil RG. Regulation of blood-brain barrier permeability by transient receptor potential type C and type v calcium-permeable channels. Microcirculation 2008; 15:359-71. [PMID: 18464164 DOI: 10.1080/10739680701762656] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To identify plasma membrane ion channels mediating calcium influx at the blood-brain barrier in response to disrupting stimuli. METHODS We examined the expression and function of candidate transient receptor potential channels using reverse transcriptase polymerase chain recation, Fura-2 calcium imaging, and permeability assays. RESULTS Immortalized mouse brain microvessel endothelial cells expressed multiple transient receptor potential isoforms: transient receptor potential C1, C2, C4, and C7, M2, M3, M4, and M7, and V2 and V4. Similar profiles were observed in freshly isolated cerebral microvessels and primary cultured rat brain endothelial cells. Thrombin-stimulated calcium influx in brain endothelial cells was blocked by transient receptor potential C inhibitors. Transient receptor potential V activating stimuli also increased intracellular calcium. This increase was inhibited by a transient receptor potential V blocker or by removal of extracellular calcium. Barrier integrity was compromised by thrombin, hypo-osmolar stress, and PMA treatment. The increase in barrier permeability induced by transient receptor potential V activators was blocked by transient receptor potential V inhibition, while thrombin effects were inhibited by transient receptor potential C inhibitors. CONCLUSIONS These results demonstrate that transient receptor potential C and transient receptor potential V channels mediate calcium influx at the blood-brain barrier, and as a consequence, may modulate barrier integrity.
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Affiliation(s)
- Rachel C Brown
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, USA
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Hertz L. Bioenergetics of cerebral ischemia: a cellular perspective. Neuropharmacology 2008; 55:289-309. [PMID: 18639906 DOI: 10.1016/j.neuropharm.2008.05.023] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Revised: 05/14/2008] [Accepted: 05/14/2008] [Indexed: 12/27/2022]
Abstract
In cerebral ischemia survival of neurons, astrocytes, oligodendrocytes and endothelial cells is threatened during energy deprivation and/or following re-supply of oxygen and glucose. After a brief summary of characteristics of different cells types, emphasizing the dependence of all on oxidative metabolism, the bioenergetics of focal and global ischemia is discussed, distinguishing between events during energy deprivation and subsequent recovery attempt after re-circulation. Gray and white matter ischemia are described separately, and distinctions are made between mature and immature brains. Next comes a description of bioenergetics in individual cell types in culture during oxygen/glucose deprivation or exposure to metabolic inhibitors and following re-establishment of normal aerated conditions. Due to their expression of NMDA and non-NMDA receptors neurons and oligodendrocytes are exquisitely sensitive to excitotoxicity by glutamate, which reaches high extracellular concentrations in ischemic brain for several reasons, including failing astrocytic uptake. Excitotoxicity kills brain cells by energetic exhaustion (due to Na(+) extrusion after channel-mediated entry) combined with mitochondrial Ca(2+)-mediated injury and formation of reactive oxygen species. Many (but not all) astrocytes survive energy deprivation for extended periods, but after return to aerated conditions they are vulnerable to mitochondrial damage by cytoplasmic/mitochondrial Ca(2+) overload and to NAD(+) deficiency. Ca(2+) overload is established by reversal of Na(+)/Ca(2+) exchangers following Na(+) accumulation during Na(+)-K(+)-Cl(-) cotransporter stimulation or pH regulation, compensating for excessive acid production. NAD(+) deficiency inhibits glycolysis and eventually oxidative metabolism, secondary to poly(ADP-ribose)polymerase (PARP) activity following DNA damage. Hyperglycemia can be beneficial for neurons but increases astrocytic death due to enhanced acidosis.
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Affiliation(s)
- Leif Hertz
- College of Basic Medical Sciences, China Medical University, Shenyang, PR China.
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Bondarenko A, Sagach V. Na+-K+-ATPase is involved in the sustained ACh-induced hyperpolarization of endothelial cells from rat aorta. Br J Pharmacol 2006; 149:958-65. [PMID: 17001300 PMCID: PMC2014692 DOI: 10.1038/sj.bjp.0706913] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND AND PURPOSE Inhibition of Na(+)-K(+)-ATPase is known to attenuate endothelium-dependent relaxation in many arteries. The purpose of this study was to evaluate the role of Na(+)-K(+)-ATPase in the regulation of endothelial membrane potential at rest and during stimulation by ACh. EXPERIMENTAL APPROACH Membrane potential was recorded from the endothelium of rat aorta using the perforated patch-clamp technique. KEY RESULTS Superfusion with K(+)-free solution produced a depolarization of about 11 mV from the resting value of -42.9+/-0.9 mV. Reintroduction of 4.7 mM K(+) transiently hyperpolarized endothelial cells to -52.4+/-1.8 mV and the membrane potential recovered within 10 min. Ouabain 500 microM depolarized endothelium by about 11 mV and inhibited the hyperpolarization induced by K(+) reintroduction into the K(+)-free solution. However, 500 nM ouabain did not affect the resting membrane potential or the hyperpolarization induced by K(+) reintroduction. Pre-exposure to ouabain 500 microM, but not 500 nM, attenuated the sustained component of hyperpolarization to ACh without affecting the amplitude of the transient peak hyperpolarization. In K(+)-free solution, the amplitude of peak hyperpolarization to ACh was increased, while the sustained component of hyperpolarization was attenuated. CONCLUSIONS AND IMPLICATIONS These results indicate that electrogenic Na(+)-K(+)-ATPase partially contributes to the sustained hyperpolarization of endothelial cells from rat aorta in response to ACh. They also suggest that the alpha1, but not alpha2 or alpha3 isoforms, is involved in ACh-mediated hyperpolarization.
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Affiliation(s)
- A Bondarenko
- Department of Blood Circulation, AA Bogomoletz Institute of Physiology, NAS of Ukraine, Kiev, Ukraine.
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Kim MY, Seol GH, Liang GH, Kim JA, Suh SH. Na+-K+ pump activation inhibits endothelium-dependent relaxation by activating the forward mode of Na+/Ca2+ exchanger in mouse aorta. Am J Physiol Heart Circ Physiol 2005; 289:H2020-9. [PMID: 15994853 DOI: 10.1152/ajpheart.00908.2004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of Na+-K+ pump activation on endothelium-dependent relaxation (EDR) and on intracellular Ca2+ concentration ([Ca2+]i) was examined in mouse aorta and mouse aortic endothelial cells (MAECs). The Na+-K+ pump was activated by increasing extracellular K+ concentration ([K+]o) from 6 to 12 mM. In aortic rings, the Na+ ionophore monensin evoked EDR, and this EDR was inhibited by the Na+/Ca2+ exchanger (NCX; reverse mode) inhibitor KB-R7943. Monensin-induced Na+ loading or extracellular Na+ depletion (Na+ replaced by Li+) increased [Ca2+]i in MAECs, and this increase was inhibited by KB-R7943. Na+-K+ pump activation inhibited EDR and [Ca2+]i increase (K+-induced inhibition of EDR and [Ca2+]i increase). The Na+-K+ pump inhibitor ouabain inhibited K+-induced inhibition of EDR. Monensin (>0.1 microM) and the NCX (forward and reverse mode) inhibitors 2'4'-dichlorobenzamil (>10 microM) or Ni2+ (>100 microM) inhibited K+-induced inhibition of EDR and [Ca2+]i increase. KB-R7943 did not inhibit K+-induced inhibition at up to 10 microM but did at 30 microM. In current-clamped MAECs, an increase in [K+]o from 6 to 12 mM depolarized the membrane potential, which was inhibited by ouabain, Ni2+, or KB-R7943. In aortic rings, the concentration of cGMP was significantly increased by acetylcholine and decreased on increasing [K+]o from 6 to 12 mM. This decrease in cGMP was significantly inhibited by pretreating with ouabain (100 microM), Ni2+ (300 microM), or KB-R7943 (30 microM). These results suggest that activation of the forward mode of NCX after Na+-K+ pump activation inhibits Ca2+ mobilization in endothelial cells, thereby modulating vasomotor tone.
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Affiliation(s)
- Moon Young Kim
- Dept. of Physiology, College of Medicine, Ewha Women's Univ., 911-1 Mok-6-dong, Yang Chun-gu, Seoul, Republic of Korea 158-710
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Dong XH, Komiyama Y, Nishimura N, Masuda M, Takahashi H. Nanomolar level of ouabain increases intracellular calcium to produce nitric oxide in rat aortic endothelial cells. Clin Exp Pharmacol Physiol 2005; 31:276-83. [PMID: 15191398 DOI: 10.1111/j.1440-1681.2004.03995.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Changes in [Ca(2+)](i) across the cell membrane and/or the sarcoplasmic reticulum regulate endothelial nitric oxide (NO) synthase activity. In the present study, we investigated the effect of ouabain, a specific inhibitor of Na(+)/K(+)-ATPase, on NO release and [Ca(2+)](i) movements in cultured rat aortic endothelial cells (RAEC) by monitoring NO production continuously using an NO-specific real-time sensor and by measuring the change in [Ca(2+)](i) using a fluorescence microscopic imaging technique with high-speed wavelength switching. The t((1/2)) (half-time of the decline of [Ca(2+)](i) to basal levels after stimulation with 10 micro mol/L bradykinin) was used as an index of [Ca(2+)](i) extrusion. A very low concentration of ouabain (10 nmol/L) did not increase the peak of NO production, but decreased the decay of NO release and, accordingly, increased integral NO production by the maximal dose-response concentration induced by bradykinin. The same dose of ouabain affected [Ca(2+)](i) movements across the cell membrane and/or sarcoplasmic reticulum induced by bradykinin with a time-course similar to that of NO release. Moreover, the t((1/2)) was significantly increased. Pretreatment of RAEC with Na(+)-free solution, an inhibitor of the Na(+)/Ca(2+) exchanger, and nickel chloride hexahydrate prevented the effects induced by bradykinin and ouabain. These observations using real-time recording indicate that a small amount of ouabain contributes to the bradykinin-stimulated increase of NO production through inhibition of plasma membrane Na(+)/K(+)-ATPase activity and an increase in intracellular Na(+) concentrations. The membrane was then depolarized, leading to a decline in the bradykinin-stimulated increase in [Ca(2+)](i) by forward mode Na(+)/Ca(2+) exchange to prolong the Ca(2+) signal time. From these results, we suggest that nanomolar levels of ouabain modulate [Ca(2+)](i) movements and NO production in RAEC.
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Affiliation(s)
- Xian Hui Dong
- Department of Clinical Sciences and Laboratory Medicine, Kansai Medical University, Moriguchi, Osaka, Japan
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Gerencser AA, Adam-Vizi V. Mitochondrial Ca2+ dynamics reveals limited intramitochondrial Ca2+ diffusion. Biophys J 2005; 88:698-714. [PMID: 15501949 PMCID: PMC1305047 DOI: 10.1529/biophysj.104.050062] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Accepted: 10/13/2004] [Indexed: 11/18/2022] Open
Abstract
To reveal heterogeneity of mitochondrial function on the single-mitochondrion level we have studied the spatiotemporal dynamics of the mitochondrial Ca2+ signaling and the mitochondrial membrane potential using wide-field fluorescence imaging and digital image processing techniques. Here we demonstrate first-time discrete sites--intramitochondrial hotspots--of Ca2+ uptake after Ca2+ release from intracellular stores, and spreading of Ca2+ rise within the mitochondria. The phenomenon was characterized by comparison of observations in intact cells stimulated by ATP and in plasma membrane permeabilized or in ionophore-treated cells exposed to elevated buffer [Ca2+]. The findings indicate that Ca2+ diffuses laterally within the mitochondria, and that the diffusion is limited for shorter segments of the mitochondrial network. These observations were supported by mathematical simulation of buffered diffusion. The mitochondrial membrane potential was investigated using the potentiometric dye TMRM. Irradiation-induced fluctuations (flickering) of TMRM fluorescence showed synchronicity over large regions of the mitochondrial network, indicating that certain parts of this network form electrical syncytia. The spatial extension of these syncytia was decreased by 2-aminoethoxydiphenyl borate (2-APB) or by propranolol (blockers of nonclassical mitochondrial permeabilities). Our data suggest that mitochondria form syncytia of electrical conductance whereas the passage of Ca2+ is restricted to the individual organelle.
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Affiliation(s)
- Akos A Gerencser
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
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Savina A, Fader CM, Damiani MT, Colombo MI. Rab11 Promotes Docking and Fusion of Multivesicular Bodies in a Calcium-Dependent Manner. Traffic 2004; 6:131-43. [PMID: 15634213 DOI: 10.1111/j.1600-0854.2004.00257.x] [Citation(s) in RCA: 366] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Multivesicular bodies (MVBs) are membranous structures within 60-100 nm diameter vesicles accumulate. MVBs are generated after invagination and pinching off of the endosomal membrane in the lumen of the vacuole. In certain cell types, fusion of MVBs with the plasma membrane results in the release of the internal vesicles called exosomes. In this report we have examined how an increase in cytosolic calcium affects the development of MVBs and exosome release in K562 cells overexpressing GFP-Rab11 wt or its mutants. In cells overexpressing the Rab11Q70 L mutant or Rab11 wt, an increase in the cytosolic calcium concentration induced by monensin caused a marked enlargement of the MVBs. This effect was abrogated by the membrane permeant calcium chelator BAPTA-AM. We also examined the behavior of MVBs in living cells by time lapse confocal microscopy. Many MVBs, decorated by wt or Q70L mutant GFP-Rab11, were docked and ready to fuse in the presence of a calcium chelator. This observation suggests that Rab11 is acting in the tethering/docking of MVBs to promote homotypic fusion, but that the final fusion reaction requires the presence of calcium. Additionally, a rise in intracellular calcium concentration enhanced exosome secretion in Rab11 wt overexpressing cells and reversed the inhibition of the mutants. The results suggest that both Rab11 and calcium are involved in the homotypic fusion of MVBs.
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Affiliation(s)
- Ariel Savina
- Laboratorio de Biología Celular y Molecular-Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo--CONICET, Mendoza, 5500, Argentina
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Bondarenko A. Sodium-calcium exchanger contributes to membrane hyperpolarization of intact endothelial cells from rat aorta during acetylcholine stimulation. Br J Pharmacol 2004; 143:9-18. [PMID: 15289290 PMCID: PMC1575260 DOI: 10.1038/sj.bjp.0705866] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The role of sodium-calcium exchanger in acetylcholine (Ach)-induced hyperpolarization of intact endothelial cells was studied in excised rat aorta. The membrane potential was recorded using perforated patch-clamp technique. 2. The mean resting potential of endothelial cells was -44.1+/-1.4 mV. A selective inhibitor of sodium-calcium exchanger benzamil (100 microm) had no significant effect on resting membrane potential, but reversibly decreased the amplitude of sustained Ach-induced endothelial hyperpolarization from 20.9+/-1.4 to 5.7+/-1.1 mV when applied during the plateau phase. 3. The blocker of reversed mode of the exchanger KB-R7943 (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methanesulfonate, 20 microm) reversibly decreased the amplitude of sustained Ach-induced hyperpolarization from 20.5+/-2.9 to 7.5+/-1.8 mV. 4. Introduction of tetraethylammonium (10 mm) in the continuous presence of Ach decreased the sustained phase of hyperpolarization from 17.9+/-1.5 by 12.9+/-0.9 mV. Subsequent addition of 20 microm KB-R7943 further depolarized endothelial cells by 4.8+/-1.1 mV. 5. Substituting external sodium with N-methyl d-glucamine during the plateau phase of Ach-evoked hyperpolarization reversibly decreased the hyperpolarization from -61.8+/-2.7 to -54.2+/-1.9 mV. In the majority of preparations, the initial response to removal of external sodium was a transient further rise in the membrane potential of several mV. Sodium ionophore monensin hyperpolarized endothelium by 10.3+/-0.7 mV. 6. The inhibitory effect of benzamil on Ach-induced endothelial sustained hyperpolarization was observed in endothelium mechanically isolated from smooth muscle. 7. These results suggest that the sodium-calcium exchanger of intact endothelial cells is able to operate in reverse following stimulation by Ach, contributing to sustained hyperpolarization. Myoendothelial electrical communications do not mediate the effect of blockers of sodium-calcium exchanger.
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MESH Headings
- Acetylcholine/pharmacology
- Adrenergic alpha-Agonists/pharmacology
- Amiloride/analogs & derivatives
- Amiloride/pharmacology
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Calcium/metabolism
- Cell Membrane/metabolism
- Cell Membrane/physiology
- Diuretics/pharmacology
- Endothelial Cells/drug effects
- Endothelial Cells/metabolism
- Endothelial Cells/physiology
- Female
- Gap Junctions/drug effects
- In Vitro Techniques
- Ionophores/pharmacology
- Male
- Membrane Potentials/drug effects
- Monensin/pharmacology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Phenylephrine/pharmacology
- Rats
- Sodium/physiology
- Sodium-Calcium Exchanger/physiology
- Stimulation, Chemical
- Thiourea/analogs & derivatives
- Thiourea/pharmacology
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Affiliation(s)
- Alexander Bondarenko
- Department of Blood Circulation, AA Bogomoletz Institute of Physiology, NAS of Ukraine, 4, Bogomoletz Str., Kiev 01024, Ukraine.
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27
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Brown RC, Mark KS, Egleton RD, Davis TP. Protection against hypoxia-induced blood-brain barrier disruption: changes in intracellular calcium. Am J Physiol Cell Physiol 2004; 286:C1045-52. [PMID: 15075203 DOI: 10.1152/ajpcell.00360.2003] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tissue damage after stroke is partly due to disruption of the blood-brain barrier (BBB). Little is known about the role of calcium in modulating BBB disruption. We investigated the effect of hypoxic and aglycemic stress on BBB function and intracellular calcium levels. Bovine brain microvessel endothelial cells were treated with A-23187 to increase intracellular calcium without hypoxia or treated with a calcium chelator (BAPTA) or calcium channel blockers (nifedipine or SKF-96365) and 6 h of hypoxia. A-23187 alone did not increase paracellular permeability. Hypoxia increased intracellular calcium, and hypoxia or hypoxia-aglycemia increased paracellular permeability. Treatment with nifedipine and SKF-96365 increased intracellular calcium under normoglycemic conditions, instead of blocking calcium influx, and was protective against hypoxia-induced BBB disruption under normoglycemia. Protection by nifedipine and SKF-96365 was not due to antioxidant properties of these compounds. These data indicate that increased intracellular calcium alone is not enough to disrupt the BBB. However, increased intracellular calcium after drug treatment and hypoxia suggests a potential mechanism for these drugs in BBB protection; nifedipine and SKF-96365 plus hypoxic stress may trigger calcium-mediated signaling cascades, altering BBB integrity.
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Affiliation(s)
- Rachel C Brown
- Dept. of Pharmacology, PO Box 24-5050, The Univ. of Arizona College of Medicine, 1501 N. Campbell Ave., Tucson, AZ 85724-5050, USA
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28
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Csanády L, Adam-Vizi V. Ca(2+)- and voltage-dependent gating of Ca(2+)- and ATP-sensitive cationic channels in brain capillary endothelium. Biophys J 2003; 85:313-27. [PMID: 12829486 PMCID: PMC1303087 DOI: 10.1016/s0006-3495(03)74476-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2002] [Accepted: 04/10/2003] [Indexed: 10/21/2022] Open
Abstract
Biophysical properties of the Ca(2+)-activated nonselective cation channel expressed in brain capillaries were studied in inside-out patches from primary cultures of rat brain microvascular endothelial cells. At -40 mV membrane potential, open probability (P(o)) was activated by cytosolic [Ca(2+)] > 1 micro M and was half-maximal at approximately 20 micro M. Increasing [Ca(2+)] stimulated opening rate with little effect on closing rate. At constant [Ca(2+)], P(o) was voltage-dependent, and effective gating charge corresponded to 0.6 +/- 0.1 unitary charges. Depolarization accelerated opening and slowed closing, thereby increasing apparent affinity for Ca(2+). Within approximately 1 min of excision, P(o) declined to a lower steady state with decreased sensitivity toward activating Ca(2+) when studied at a fixed voltage, and toward activating voltage when studied at a fixed [Ca(2+)]. Deactivated channels opened approximately 5-fold slower and closed approximately 10-fold faster. The sulfhydryl-reducing agent dithiotreitol (1 mM) completely reversed acceleration of closing rate but failed to recover opening rate. Single-channel gating was complex; distributions of open and closed dwell times contained at least four and five exponential components, respectively. The longest component of the closed-time distribution was markedly sensitive to both [Ca(2+)] and voltage. We conclude that the biophysical properties of gating of this channel are remarkably similar to those of large-conductance Ca(2+)-activated K(+) channels.
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Affiliation(s)
- László Csanády
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary.
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29
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Jeon D, Yang YM, Jeong MJ, Philipson KD, Rhim H, Shin HS. Enhanced learning and memory in mice lacking Na+/Ca2+ exchanger 2. Neuron 2003; 38:965-76. [PMID: 12818181 DOI: 10.1016/s0896-6273(03)00334-9] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The plasma membrane Na(+)/Ca(2+) exchanger (NCX) plays a role in regulation of intracellular Ca(2+) concentration via the forward mode (Ca(2+) efflux) or the reverse mode (Ca(2+) influx). To define the physiological function of the exchanger in vivo, we generated mice deficient for NCX2, the major isoform in the brain. Mutant hippocampal neurons exhibited a significantly delayed clearance of elevated Ca(2+) following depolarization. The frequency threshold for LTP and LTD in the hippocampal CA1 region was shifted to a lowered frequency in the mutant mice, thereby favoring LTP. Behaviorally, the mutant mice exhibited enhanced performance in several hippocampus-dependent learning and memory tasks. These results demonstrate that NCX2 can be a temporal regulator of Ca(2+) homeostasis and as such is essential for the control of synaptic plasticity and cognition.
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Affiliation(s)
- Daejong Jeon
- National Creative Research Initiative Center for Calcium & Learning, Korea Institute of Science and Technology, 136-791, Seoul, South Korea
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30
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Savina A, Furlán M, Vidal M, Colombo MI. Exosome release is regulated by a calcium-dependent mechanism in K562 cells. J Biol Chem 2003; 278:20083-90. [PMID: 12639953 DOI: 10.1074/jbc.m301642200] [Citation(s) in RCA: 608] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Multivesicular bodies (MVBs) are endocytic structures that contain small vesicles formed by the budding of an endosomal membrane into the lumen of the compartment. Fusion of MVBs with the plasma membrane results in secretion of the small internal vesicles termed exosomes. K562 cells are a hematopoietic cell line that releases exosomes. The application of monensin (MON) generated large MVBs that were labeled with a fluorescent lipid. Exosome release was markedly enhanced by MON treatment, a Na+/H+ exchanger that induces changes in intracellular calcium (Ca2+). To explore the possibility that the effect of MON on exosome release was caused via an increase in Ca2+, we have used a calcium ionophore and a chelator of intracellular Ca2+. Our results indicate that increasing intracellular Ca2+ stimulates exosome secretion. Furthermore, MON-stimulated exosome release was completely eliminated by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM), implying a requirement for Ca2+ in this process. We have observed that the large MVBs generated in the presence of MON accumulated Ca2+ as determined by labeling with Fluo3-AM, suggesting that intralumenal Ca2+ might play a critical role in the secretory process. Interestingly, our results indicate that transferrin (Tf) stimulated exosome release in a Ca2+-dependent manner, suggesting that Tf might be a physiological stimulus for exosome release in K562 cells.
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Affiliation(s)
- Ariel Savina
- Laboratorio de Biología Celular y Molecular-Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 5500 Mendoza, Argentina
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31
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Schneider JC, El Kebir D, Chéreau C, Mercier JC, Dall'Ava-Santucci J, Dinh-Xuan AT. Involvement of Na(+)/Ca(2+) exchanger in endothelial NO production and endothelium-dependent relaxation. Am J Physiol Heart Circ Physiol 2002; 283:H837-44. [PMID: 12124234 DOI: 10.1152/ajpheart.00789.2001] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Endothelial nitric oxide (NO) synthase (eNOS) is controlled by Ca(2+)/calmodulin and caveolin-1 in caveolae. It has been recently suggested that Na(+)/Ca(2+) exchanger (NCX), also expressed in endothelial caveolae, is involved in eNOS activation. To investigate the role played by NCX in NO synthesis, we assessed the effects of Na(+) loading (induced by monensin) on rat aortic rings and cultured porcine aortic endothelial cells. Effect of monensin was evaluated by endothelium-dependent relaxation of rat aortic rings in response to acetylcholine and by real-time measurement of NO release from cultured endothelial cells stimulated by A-23187 and bradykinin. Na(+) loading shifted the acetylcholine concentration-response curve to the left. These effects were prevented by pretreatment with the NCX inhibitors benzamil and KB-R7943. Monensin potentiated Ca(2+)-dependent NO release in cultured cells, whereas benzamil and KB-R7943 totally blocked Na(+) loading-induced NO release. These findings confirm the key role of NCX in reverse mode on Ca(2+)-dependent NO production and endothelium-dependent relaxation.
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Affiliation(s)
- Jean-Christophe Schneider
- Service de Physiologie-Explorations Fonctionnelles, Centre Hospitalier Universitaire Cochon, Assistance Publique, Hôpitaux de Paris, Université Paris 5, 75014 Paris, France
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32
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Wang X, Reznick S, Li P, Liang W, van Breemen C. Ca(2+) removal mechanisms in freshly isolated rabbit aortic endothelial cells. Cell Calcium 2002; 31:265-77. [PMID: 12098216 DOI: 10.1016/s0143-4160(02)00075-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Calcium removal from the cytoplasm was investigated in freshly isolated aortic endothelial cells by monitoring changes in intracellular calcium ([Ca(2+)](i)) using ratiometric fura-2 fluorimetry. Blockade of the Na(+)/Ca(2+) exchanger (NCX) by replacement of external sodium with equi-molar N-methyl-D-glutamine (0Na PSS) decreased the removal rate by 52%. Blockade of the sarco/endoplasmic reticulum Ca(2+) ATPase (SERCA) by cyclopiazonic acid (CPA) decreased the removal rate by 50%. Simultaneous application of CPA and 0Na PSS did not reduce the removal rate any further (53%). The lack of additivity of these two procedures, suggests that SERCA and the NCX function in series to lower [Ca(2+)](i). In addition, in the absence of extracellular Ca(2+), removal of external Na(+) markedly reduced the rate of loss of Ca(2+) from the ER further supporting the hypothesis that NCX is functionally linked to ER calcium release channels, and thus, plays an important role in ER calcium unloading. To investigate the mechanism for the coupling of NCX and SERCA, the same protocols as described above were repeated after treating the cells with cytochalasin D, which disrupts the cytoskeleton. This treatment uncoupled the NCX from SERCA, as evidenced by the resulting additive inhibitory effects of application of CPA and removal of extracellular Na(+) on the rate of Ca(2+) removal from the cytoplasm. These data suggest that in endothelial cells NCX and SERCA function in series to remove about half of the free Ca(2+) from the cytosol, while PMCA contributes to the other half of the Ca(2+) removal process.
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Affiliation(s)
- X Wang
- Department of Pharmacology and Therapeutics, Vancouver Vascular Biology Research Center, University of British Columbia, Vancouver, Canada V6T 1Z3.
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33
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Abstract
Ions in the brain are regulated independently from plasma levels by active transport across choroid plexus epithelium and cerebral capillary endothelium, assisted by astrocytes. In "resting" brain tissue, extracellular potassium ([K+]o) is lower and [H]o is higher (i.e., pHo is lower) than elsewhere in the body. This difference probably helps to maintain the stability of cerebral function because both high [K]o and low [H+]o enhance neuron excitability. Decrease in osmolarity enhances synaptic transmission and neuronal excitability whereas increased osmolarity has the opposite effect. Iso-osmotic low Na+ concentration also enhances voltage-dependent Ca2+ currents and synaptic transmission. Hypertonicity is the main cause of diabetic coma. In normally functioning brain tissue, the fluctuations in ion levels are limited, but intense neuronal excitation causes [K+]o to rise and [Na+]o, [Ca2+]o to fall. When excessive excitation, defective inhibition, energy failure, mechanical trauma, or blood-brain barrier defects drive ion levels beyond normal limits, positive feedback can develop as abnormal ion distributions influence neuron function, which in turn aggravates ion maldistribution. Computer simulation confirmed that elevation of [K+]o can lead to such a vicious circle and ignite seizures, spreading depression (SD), or hypoxic SD-like depolarization (anoxic depolarization).
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Affiliation(s)
- George G Somjen
- Department of Cell Biology and Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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34
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Moccia F, Berra-Romani R, Baruffi S, Spaggiari S, Signorelli S, Castelli L, Magistretti J, Taglietti V, Tanzi F. Ca2+ uptake by the endoplasmic reticulum Ca2+-ATPase in rat microvascular endothelial cells. Biochem J 2002; 364:235-44. [PMID: 11988097 PMCID: PMC1222566 DOI: 10.1042/bj3640235] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In non-excitable cells, many agonists increase the intracellular Ca(2+) concentration ([Ca(2+)](i)) by inducing an inositol 1,4,5-trisphosphate (IP(3))-mediated Ca(2+) release from the intracellular stores. Ca(2+) influx from the extracellular medium may then sustain the Ca(2+) signal. [Ca(2+)](i) recovers its resting level as a consequence of Ca(2+)-removing mechanisms, i.e. plasma-membrane Ca(2+)-ATPase (PMCA) pump, Na(+)/Ca(2+) exchanger (NCX) and sarco-endoplasmic reticulum Ca(2+)-ATPase (SERCA) pump. In a study performed in pancreatic acinar cells, evidence has been provided suggesting that, during the decay phase of the agonist-evoked Ca(2+) transients, the Ca(2+) concentration within the intracellular stores remains essentially constant [Mogami, Tepikin and Petersen (1998) EMBO J. 17, 435-442]. It was therefore hypothesized that, in such a situation, intracellular Ca(2+) is not only picked up by the SERCA pump, but is also newly released through IP(3)-sensitive Ca(2+) channels, with the balance between these two processes being approximately null. The main aim of the present work was to test this hypothesis by a different experimental approach. Using cardiac microvascular endothelial cells, we found that inhibition of the SERCA pump has no effect on the time course of agonist-evoked Ca(2+) transients. This result was not due to a low capacity of the SERCA pump since, after agonist removal, this pump proved to be very powerful in clearing the excess of intracellular Ca(2+). We showed further that: (i) in order to avoid a rapid removal of Ca(2+) by the SERCA pump, continuous IP(3) production appears to be required throughout all of the decay phase of the Ca(2+) transient; and (ii) Ca(2+) picked up by the SERCA pump can be fully and immediately released by agonist application. All these results support the model of Mogami, Tepikin and Petersen [(1998) EMBO J. 17, 435-442]. Since the SERCA pump did not appear to be involved in shaping the decay phase of the agonist-evoked Ca(2+) transient, we inhibited the PMCA pump with carboxyeosin, and NCX with benzamil and by removing extracellular Na(+). The results indicate that, during the decay phase of the agonist-evoked Ca(2+) transient, the intracellular Ca(2+) is removed by both the PMCA pump and NCX. Finally, we provide evidence indicating that mitochondria have no role in clearing intracellular Ca(2+) during agonist-evoked Ca(2+) transients.
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Affiliation(s)
- Francesco Moccia
- Department of Physiological and Pharmacological Sciences, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
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35
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Gerencsér AA AA, Adam-Vizi V. Selective, high-resolution fluorescence imaging of mitochondrial Ca2+ concentration. Cell Calcium 2001; 30:311-21. [PMID: 11733937 DOI: 10.1054/ceca.2001.0238] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We have developed a digital image processing technique based on highpass filtering of microfluorimetric images for selective transmission of fine image details corresponding to mitochondria. This technique enabled the detection of the mitochondrial calcium signals with high selectivity, simultaneously with the cytosolic calcium signal. The validity of this technique was supported in primary cultures of rat brain capillary endothelial cells loaded with X-rhod-1 by the results that (i) inhibition of the mitochondrial Ca2+ uptake by discharging the mitochondrial membrane potential selectively abolished the transient of the highpass filtered signal evoked by ATP, and (ii) CGP-37157, a selective blocker of the mitochondrial Na+/Ca2+ exchanger, increased the peak amplitude of highpass filtered (mitochondrial) Ca2+ transients and caused a sustained plateau. The highpass filtering technique enabled the analysis of the mitochondrial Ca2+ transients in high temporal resolution. We found a uniform and monophasic rise of [Ca2+] in the mitochondrial population of the cell, following the cytosolic [Ca2+] with a delay at onset and peak. The introduced highpass filtering technique is a powerful tool in the high spatial and temporal resolution analysis of mitochondrial calcium transients, and it could be especially important in specimens where genetically targeted probes fail.
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Affiliation(s)
- A A Gerencsér AA
- Department of Medical Biochemistry, Semmelweis University, Budapest, H-1444 P.O. Box 262, Hungary
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36
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Abstract
Endothelial cells (EC) form a unique signal-transducing surface in the vascular system. The abundance of ion channels in the plasma membrane of these nonexcitable cells has raised questions about their functional role. This review presents evidence for the involvement of ion channels in endothelial cell functions controlled by intracellular Ca(2+) signals, such as the production and release of many vasoactive factors, e.g., nitric oxide and PGI(2). In addition, ion channels may be involved in the regulation of the traffic of macromolecules by endocytosis, transcytosis, the biosynthetic-secretory pathway, and exocytosis, e.g., tissue factor pathway inhibitor, von Willebrand factor, and tissue plasminogen activator. Ion channels are also involved in controlling intercellular permeability, EC proliferation, and angiogenesis. These functions are supported or triggered via ion channels, which either provide Ca(2+)-entry pathways or stabilize the driving force for Ca(2+) influx through these pathways. These Ca(2+)-entry pathways comprise agonist-activated nonselective Ca(2+)-permeable cation channels, cyclic nucleotide-activated nonselective cation channels, and store-operated Ca(2+) channels or capacitative Ca(2+) entry. At least some of these channels appear to be expressed by genes of the trp family. The driving force for Ca(2+) entry is mainly controlled by large-conductance Ca(2+)-dependent BK(Ca) channels (slo), inwardly rectifying K(+) channels (Kir2.1), and at least two types of Cl( -) channels, i.e., the Ca(2+)-activated Cl(-) channel and the housekeeping, volume-regulated anion channel (VRAC). In addition to their essential function in Ca(2+) signaling, VRAC channels are multifunctional, operate as a transport pathway for amino acids and organic osmolytes, and are possibly involved in endothelial cell proliferation and angiogenesis. Finally, we have also highlighted the role of ion channels as mechanosensors in EC. Plasmalemmal ion channels may signal rapid changes in hemodynamic forces, such as shear stress and biaxial tensile stress, but also changes in cell shape and cell volume to the cytoskeleton and the intracellular machinery for metabolite traffic and gene expression.
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Affiliation(s)
- B Nilius
- Department of Physiology, KU Leuven, Campus Gasthuisberg, Leuven, Belgium.
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37
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Horikawa N, Kuribayashi Y, Itoh N, Nishioka M, Matsui K, Kawamura N, Ohashi N. Na+/H+ exchange inhibitor SM-20220 improves endothelial dysfunction induced by ischemia-reperfusion. JAPANESE JOURNAL OF PHARMACOLOGY 2001; 85:271-7. [PMID: 11325019 DOI: 10.1254/jjp.85.271] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Endothelial cells play an important role in the physiologic homeostasis of the cerebral circulation. Previously, we showed that the Na+/H+ exchanger (NHE) inhibitor SM-20220 (N-(aminoimino-methyl)-1-methyl-1H-indole-2-carboxamide methanesulfonate) improved ischemic brain injury. In this study, we investigated the effect of SM-20220 on cerebrovascular dysfunction after ischemia-reperfusion, focusing on the kinds of dysfunction that involved endothelial function. In cultured bovine brain microvascular endothelial cells (BBMCs), the IC50 value for the NHE activity of SM-20220 was 4 x 10(-8) M. SM-20220 also reduced the cell injury induced by hypoxia/aglycemia-reoxygenation in BBMCs, with statistical significance at 10(-7) M (P<0.05). Next, the effect of SM-20220 on disruption of the blood-brain barrier and cerebral blood flow were evaluated using transient middle cerebral artery (MCA) occlusion models. Intravenous infusion of SM-20220 (0.4 mg/kg per hour for 1 h) attenuated the extravasation of Evans blue, a blood-brain barrier disruption indicator, into cerebral tissue on the day after transient ischemia (P<0.05). The occlusion of the MCA decreased the cerebral blood flow in the MCA territory by about 20%, and only about 45% of the preischemic value was recovered at 1-h reperfusion. A bolus injection of SM-20220 (1 mg/kg, i.v.) improved the postischemic hypoperfusion by about 75%, without causing changes in the systemic blood pressure. These results indicate that the protective effect of NHE inhibitor on ischemic brain injury may be at least partially mediated by the prevention of endothelial dysfunction.
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Affiliation(s)
- N Horikawa
- Sumitomo Pharmaceuticals Research Division, Osaka, Japan
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38
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Sipos I, Dömötör E, Abbott NJ, Adam-Vizi V. The pharmacology of nucleotide receptors on primary rat brain endothelial cells grown on a biological extracellular matrix: effects on intracellular calcium concentration. Br J Pharmacol 2000; 131:1195-203. [PMID: 11082128 PMCID: PMC1572433 DOI: 10.1038/sj.bjp.0703675] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2000] [Revised: 08/24/2000] [Accepted: 08/29/2000] [Indexed: 12/13/2022] Open
Abstract
1. Brain capillary endothelial cells express a variety of nucleotide receptors, but differences have been reported between culture models. This study reports examination of nucleotide receptors on primary cultured rat brain capillary endothelial cells (RBCEC) grown on a biological extracellular matrix (ECM) to produce a more differentiated phenotype. 2. Fura-2 fluorescence ratio imaging was used to monitor intracellular free calcium concentration [Ca(2+)](i). ATP, UTP, and 2-methylthioATP (2-MeSATP) increased [Ca(2+)](i) to similar levels, while 2-MeSADP, ADP and adenosine gave smaller responses. 3. Removal of extracellular calcium caused no significant change in the [Ca(2+)](i) response to 2-MeSATP, evidence that the response was mediated by a metabotropic (P2Y) receptor. 4. All cells tested responded to ATP, UTP, 2-MeSATP and ADP, while 63% responded to adenosine and 50% to 2-MeSADP. No cells responded to alpha, beta-methyleneATP. Cells grown on rat tail collagen instead of ECM gave smaller and less uniform [Ca(2+)](i) responses, suggesting that the differentiating effect of the ECM contributed to a more uniform receptor profile. 5. The [Ca(2+)](i) response to the P2Y(1)-selective agonist 2-MeSADP was abolished in the presence of the subtype-selective antagonist adenosine 3'-phosphate 5'-phosphosulphate (PAPS). 6. The P2Y(2) antagonist suramin completely blocked the response to ATP and inhibited the response to UTP by 66%. 7. The A(1) subtype-selective adenosine receptor agonist N(6)-Cyclopentyladenosine (CPA) gave a small but characteristic [Ca(2+)](i) response, while A(2A) and A(2B) subtype-selective agonists failed to generate [Ca(2+)](i) changes. 8. The results are consistent with the presence on RBCEC of a P2Y(2)-like receptor coupled to phospholipase C, and a P2Y(1)-like receptor mobilizing intracellular Ca(2+). The role of multiple nucleotide receptors in the function of the brain endothelium is discussed.
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Affiliation(s)
- Ildikó Sipos
- Department of Medical Biochemistry, Semmelweis University, Budapest, H-1444, P.O. Box 262, Hungary
| | - Eszter Dömötör
- Department of Medical Biochemistry, Semmelweis University, Budapest, H-1444, P.O. Box 262, Hungary
| | - N Joan Abbott
- King's College London, Division of Physiology, GKT School of Biomedical Sciences, London SE1 1UL
| | - Vera Adam-Vizi
- Department of Medical Biochemistry, Semmelweis University, Budapest, H-1444, P.O. Box 262, Hungary
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39
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Paltauf-Doburzynska J, Frieden M, Spitaler M, Graier WF. Histamine-induced Ca2+ oscillations in a human endothelial cell line depend on transmembrane ion flux, ryanodine receptors and endoplasmic reticulum Ca2+-ATPase. J Physiol 2000; 524 Pt 3:701-13. [PMID: 10790152 PMCID: PMC2269898 DOI: 10.1111/j.1469-7793.2000.00701.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Using single cell microfluorometry to monitor changes in bulk Ca2+ concentration ([Ca2+]bulk) and the whole-cell configuration of the patch clamp technique to measure K+ currents (voltage clamp) and membrane potential (current clamp), the mechanisms of histamine-induced Ca2+ oscillations in the umbilical vein endothelial cell-derived cell line EA.hy926 were studied. In single cells, histamine (10 microM) evoked sinusoidal Ca2+ oscillations in low extracellular Ca2+ concentrations ([Ca2+]o = 10-30 microM). In contrast, histamine did not initiate Ca2+ oscillations either in the absence of extracellular Ca2+ (10 microM EGTA) or in the presence of 2.5 mM extracellular Ca2+. Ca2+ oscillations were accompanied by rhythmic activation of Ca2+-activated K+ (KCa) channels and membrane hyperpolarization of 18.1 +/- 3.9 mV. Hence, cell depolarization with 70 mM extracellular K+ or the inhibition of non-selective cation channels (NSCCs) and KCa channels by 10 microM Loe 908 and 10 mM tetrabutylammonium prevented histamine-evoked Ca2+ oscillations. Preventing Na+-Ca2+ exchange (NCX) by 10 microM 2', 4'-dichlorobenzamil, or removal of extracellular Na+, abolished histamine-induced Ca2+ oscillations. Lowering the extracellular Na+ concentration and thus promoting the reversed mode of NCX (3Na+ out and 1Ca2+ in) increased the amplitude and frequency of histamine-induced Ca2+ oscillations by 25 and 13 %, respectively. Hence, in the absence of extracellular Ca2+, 10 microM histamine induced an elevation of intracellular Na+ concentration in certain subplasmalemmal domains. The inhibitor of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) 2,5-di-tert-butyl-1, 4-benzo-hydroquinone (15 microM) prevented histamine-induced Ca2+ oscillations. In addition, blockage of ryanodine-sensitive Ca2+ release (RsCR) by 25 microM ryanodine blunted Ca2+ oscillations. In endothelial cells that were treated for 16 h with 10 microM nocodazole to collapse the superficial endoplasmic reticulum (sER), no histamine-induced Ca2+ oscillations were found. We conclude that in low [Ca2+]o conditions histamine-induced Ca2+ oscillations depend on transmembrane Na+ loading through NSCCs that leads to Ca2+ entry via NCX. Cation influx is controlled by KCa channel activity that triggers membrane hyperpolarization and, thus, provides the driving force for cation influx. Hence, the Ca2+ entering needs to be sequestrated via SERCA into sER to become released by RsCR to evoke Ca2+ spiking. These data further support our previous work on localized Ca2+ signalling as a key phenomenon in endothelial Ca2+ homeostasis.
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Affiliation(s)
- J Paltauf-Doburzynska
- Department of Medical Biochemistry and Medical Molecular Biology, Karl-Franzens University of Graz, Harrachgasse 21/III, A-8010 Graz, Austria
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40
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Nakao M, Furukawa K, Satoh E, Ono K, Iijima T. Inhibition by antisense oligonucleotides of plasma membrane Ca(2+) ATPase in vascular endothelial cells. Eur J Pharmacol 2000; 387:273-7. [PMID: 10650172 DOI: 10.1016/s0014-2999(99)00823-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Antisense oligodeoxynucleotides were used to knock down plasma membrane Ca(2+) ATPase, and the role of plasma membrane Ca(2+) ATPase was investigated in human aortic endothelial (HAE) cells. The peak of thapsigargin-evoked intracellular Ca(2+) concentration ([Ca(2+)](i)) was higher in antisense-treated than in untreated cells, but the declining time course was unaffected by the antisense treatment. The declining time was prolonged in both antisense-treated and untreated cells by reducing external Na(+), but the prolongation was more marked in the antisense-treated cells. These results provide the evidence of a functional role of plasma membrane Ca(2+) ATPase, although other mechanisms including Na(+)/Ca(2+) exchange may play the primary role in regulating [Ca(2+)](i).
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Affiliation(s)
- M Nakao
- Department of Pharmacology, Akita University School of Medicine, 1-1-1 Hondoh, Akita, Japan
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41
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Bartha K, Dömötör E, Lanza F, Adam-Vizi V, Machovich R. Identification of thrombin receptors in rat brain capillary endothelial cells. J Cereb Blood Flow Metab 2000; 20:175-82. [PMID: 10616806 DOI: 10.1097/00004647-200001000-00022] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Both thrombin and plasmin induce contraction of brain endothelial cells, which may increase capillary permeability thereby leading to disruption of the blood-brain barrier. Identification of thrombin receptors, as well as the influence of plasmin on their activation, in capillary endothelial cells and astrocytes are therefore essential for understanding injury-related actions of thrombin in the brain. Using the reverse transcriptase-polymerase chain reaction method, the present study shows that primary cultures of rat brain capillary endothelial (RBCE) cells and astrocytes derived from rat brain express two different thrombin receptors. The first is proteolytically activated receptor (PAR)-1, the receptor responsible for the vast majority of the thrombin's cellular activation functions; the second is PAR-3, a receptor described to be essential for normal responsiveness to thrombin in mouse platelets. In addition to these thrombin receptors, the mRNA (messenger RNA) for PAR-2, a possible trypsin receptor, was also identified. Functional significance of thrombin receptors was indicated by changes in [Ca2+]i in response to thrombin, as measured by FURA-2 fluorescence in RBCE cells. Thrombin as low as 4 nmol/L induced an abrupt increase in [Ca2+]i whereas, upon addition of active site-blocked thrombin or plasmin, [Ca2+]i remained unchanged. The [Ca2+]i signal attributable to thrombin was smaller in a low Ca2+-containing medium, indicating that an influx of Ca2+ from the extracellular medium makes a contribution to the overall [Ca2+]i rise. The amplitude of the transient [Ca2+]i signal was dependent on the concentration of thrombin, and repeated application of the enzyme caused an essentially complete and long-term desensitization of the receptor. The PAR-1 agonist peptide SFLLRN also elicited a transient increase in [Ca2+]i. After activation by SFLLRN, cells showed a diminished response to thrombin, but the response was not absent, indicating that PAR-3 might contribute to the generation of the [Ca2+]i signal. Pretreatment of RBCE cells with 100 nmol/L plasmin completely prevented [Ca2+]i rise attributable to thrombin. These data show that RBCE cells and astrocytes express at least two receptors for thrombin, PAR-1 and PAR-3, and probably both receptors are involved in thrombin-induced [Ca2+]i signals. Plasmin itself does not elevate [Ca2+]i but prevents the activation of receptors by thrombin.
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Affiliation(s)
- K Bartha
- Department of Medical Biochemistry, Semmelweis University of Medicine, Budapest, Hungary
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42
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Dömötör E, Sipos I, Kittel A, Abbott NJ, Adam-Vizi V. Improved growth of cultured brain microvascular endothelial cells on glass coated with a biological matrix. Neurochem Int 1998; 33:473-8. [PMID: 10098716 DOI: 10.1016/s0197-0186(98)00057-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An improved method for culturing primary rat brain capillary endothelial cells on glass has been developed, using a corneal extracellular matrix coat. Since the collagen-coated plastic attachment surface conventionally used for primary cultures of brain microvascular endothelium gives a high level of background fluorescence in microfluorimetric studies, an alternative attachment surface was tested involving no plastic element. Five substrata combinations were examined and a new combination of glass and corneal endothelial extracellular matrix coat was found to provide excellent cell adhesion, culture growth and purity. Other established substrata combinations tested for comparison, either involved plastic, or used glass with collagen or carbodiimide and collagen coating but the last two gave poor endothelial cell adhesion and growth. Our method using this new attachment surface combination results in stable and pure endothelial cultures, as verified by immunocytochemistry, which are suitable for fluorimetric investigations.
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Affiliation(s)
- E Dömötör
- Department of Medical Biochemistry, Semmelweis University of Medicine, Budapest, Hungary
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