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Lu F, Wang L, Chen Y, Zhong X, Huang Z. In vitro cultured calculus bovis attenuates cerebral ischaemia-reperfusion injury by inhibiting neuronal apoptosis and protecting mitochondrial function in rats. JOURNAL OF ETHNOPHARMACOLOGY 2020; 263:113168. [PMID: 32730869 DOI: 10.1016/j.jep.2020.113168] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 05/18/2020] [Accepted: 07/07/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE In vitro cultured calculus bovis (ICCB), which is produced based on the formation mechanism of bovine gallstones, is used to replace the natural bezoar. It has been used in the clinic to treat brain diseases, including stroke, Alzheimer's disease and depression. AIM OF STUDY ICCB is used to treat encephalopathy in the clinic. We explored the effects of ICCB on cerebral ischaemia-reperfusion injury (CIRI) and the potential associated mechanisms. MATERIALS AND METHODS Rats were subjected to middle cerebral artery occlusion for 90 min, followed by 24 h of reperfusion, after being given different concentrations of ICCB once a day for 3 days. Subsequently, the neurological scores, brain oedema and volume of cerebral infarction were measured, and the histopathological changes in the cortex neurons were observed by haematoxylin and eosin staining (H&E). Apoptosis was determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL). Ultrastructural changes in the mitochondria of the cortex were assessed by transmission electron microscopy (TEM). The apoptosis-related proteins Bax, Bcl-2, caspase-9, caspase-3, Mito-Cyt C and Cyto-Cyt C were detected by Western blotting. RESULTS Compared with those in the control group, the neurological scores, the volumes of cerebral infarction, and the brain water contents were significantly decreased in the ICCB groups at doses of 50 and 100 mg/kg. The ICCB treatment effectively decreased the neuronal apoptosis resulting from the CIRI-induced neuron injury. In addition, the histopathological damage and the mitochondria ultrastructure injury were partially improved in the CIRI rats after ICCB treatment. Western blotting analysis indicated that ICCB significantly decreased the expression of Bax, caspase-9, caspase-3 and Cyto-Cyt C protein levels while increasing the expression of Bcl-2 and Mito-Cyt C protein levels. CONCLUSION The ICCB protected against CIRI by suppressing the mitochondria-mediated apoptotic signalling pathway.
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Affiliation(s)
- Feibiao Lu
- Institute of Traditional Chinese Medicine Resources, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 311400, PR China
| | - Lingfeng Wang
- Institute of Traditional Chinese Medicine Resources, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 311400, PR China
| | - Yanyue Chen
- Institute of Traditional Chinese Medicine Resources, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 311400, PR China
| | - Xiaoming Zhong
- Institute of Traditional Chinese Medicine Resources, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 311400, PR China.
| | - Zhen Huang
- Institute of Traditional Chinese Medicine Resources, College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, Zhejiang, 311400, PR China.
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2
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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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3
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Abstract
SIGNIFICANCE Cellular reactive oxygen species (ROS) mediate redox signaling cascades that are critical to numerous physiological and pathological processes. Analytical methods to monitor cellular ROS levels and proteomic platforms to identify oxidative post-translational modifications (PTMs) of proteins are critical to understanding the triggers and consequences of redox signaling. Recent Advances: The prevalence and significance of redox signaling has recently been illuminated through the use of chemical probes that allow for sensitive detection of cellular ROS levels and proteomic dissection of oxidative PTMs directly in living cells. CRITICAL ISSUES In this review, we provide a comprehensive overview of chemical probes that are available for monitoring ROS and oxidative PTMs, and we highlight the advantages and limitations of these methods. FUTURE DIRECTIONS Despite significant advances in chemical probes, the low levels of cellular ROS and low stoichiometry of oxidative PTMs present challenges for accurately measuring the extent and dynamics of ROS generation and redox signaling. Further improvements in sensitivity and ability to spatially and temporally control readouts are essential to fully illuminate cellular redox signaling.
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Affiliation(s)
- Masahiro Abo
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts
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4
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Abstract
The human brain requires uninterrupted delivery of blood-borne oxygen and nutrients to sustain its function. Focal ischemia, particularly, ischemic stroke, and global ischemia imposed by cardiac arrest disrupt the brain's fuel supply. The resultant ATP depletion initiates a complex injury cascade encompassing intracellular Ca2+ overload, glutamate excitotoxicity, oxido-nitrosative stress, extracellular matrix degradation, and inflammation, culminating in neuronal and astroglial necrosis and apoptosis, neurocognitive deficits, and even death. Unfortunately, brain ischemia has proven refractory to pharmacological intervention. Many promising treatments afforded brain protection in animal models of focal and global ischemia, but failed to improve survival and neurocognitive recovery of stroke and cardiac arrest patients in randomized clinical trials. The culprits are the blood-brain barrier (BBB) that limits transferral of medications to the brain parenchyma, and the sheer complexity of the injury cascade, which presents a daunting array of targets unlikely to respond to monotherapies. Erythropoietin is a powerful neuroprotectant capable of interrupting multiple aspects of the brain injury cascade. Preclinical research demonstrates erythropoietin's ability to suppress glutamate excitotoxicity and intracellular Ca2+ overload, dampen oxidative stress and inflammation, interrupt the apoptotic cascade, and preserve BBB integrity. However, the erythropoietin dosages required to traverse the BBB and achieve therapeutically effective concentrations in the brain parenchyma impose untoward side effects. Recent discoveries that hypoxia induces erythropoietin production within the brain and that neurons, astroglia, and cerebrovascular endothelium harbor membrane erythropoietin receptors, raise the exciting prospect of harnessing endogenous erythropoietin to protect the brain from the ravages of ischemia-reperfusion.
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Affiliation(s)
- Robert T Mallet
- Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, TX, United States.
| | - Myoung-Gwi Ryou
- Institute for Cardiovascular and Metabolic Diseases, University of North Texas Health Science Center, Fort Worth, TX, United States; Tarleton State University, Fort Worth, TX, United States
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5
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Rakkar K, Bayraktutan U. Increases in intracellular calcium perturb blood–brain barrier via protein kinase C-alpha and apoptosis. Biochim Biophys Acta Mol Basis Dis 2016; 1862:56-71. [DOI: 10.1016/j.bbadis.2015.10.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 10/14/2015] [Accepted: 10/20/2015] [Indexed: 12/11/2022]
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6
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Andrikopoulos P, Kieswich J, Harwood SM, Baba A, Matsuda T, Barbeau O, Jones K, Eccles SA, Yaqoob MM. Endothelial Angiogenesis and Barrier Function in Response to Thrombin Require Ca2+ Influx through the Na+/Ca2+ Exchanger. J Biol Chem 2015; 290:18412-28. [PMID: 25979335 DOI: 10.1074/jbc.m114.628156] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Indexed: 01/11/2023] Open
Abstract
Thrombin acts on the endothelium by activating protease-activated receptors (PARs). The endothelial thrombin-PAR system becomes deregulated during pathological conditions resulting in loss of barrier function and a pro-inflammatory and pro-angiogenic endothelial phenotype. We reported recently that the ion transporter Na(+)/Ca(2+) exchanger (NCX) operating in the Ca(2+)-influx (reverse) mode promoted ERK1/2 activation and angiogenesis in vascular endothelial growth factor-stimulated primary human vascular endothelial cells. Here, we investigated whether Ca(2+) influx through NCX was involved in ERK1/2 activation, angiogenesis, and endothelial barrier dysfunction in response to thrombin. Reverse-mode NCX inhibitors and RNAi-mediated NCX1 knockdown attenuated ERK1/2 phosphorylation in response to thrombin or an agonist of PAR-1, the main endothelial thrombin receptor. Conversely, promoting reverse-mode NCX by suppressing Na(+)-K(+)-ATPase activity enhanced ERK1/2 activation. Reverse-mode NCX inhibitors and NCX1 siRNA suppressed thrombin-induced primary human vascular endothelial cell angiogenesis, quantified as proliferation and tubular differentiation. Reverse-mode NCX inhibitors or NCX1 knockdown preserved barrier integrity upon thrombin stimulation in vitro. Moreover, the reverse-mode NCX inhibitor SEA0400 suppressed Evans' blue albumin extravasation to the lung and kidneys and attenuated edema formation and ERK1/2 activation in the lungs of mice challenged with a peptide activator of PAR-1. Mechanistically, thrombin-induced ERK1/2 activation required NADPH oxidase 2-mediated reactive oxygen species (ROS) production, and reverse-mode NCX inhibitors and NCX1 siRNA suppressed thrombin-induced ROS production. We propose that reverse-mode NCX is a novel mechanism contributing to thrombin-induced angiogenesis and hyperpermeability by mediating ERK1/2 activation in a ROS-dependent manner. Targeting reverse-mode NCX could be beneficial in pathological conditions involving unregulated thrombin signaling.
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Affiliation(s)
- Petros Andrikopoulos
- From Translational Medicine and Therapeutics, William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary's University of London, London EC1M 6BQ, United Kingdom,
| | - Julius Kieswich
- From Translational Medicine and Therapeutics, William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary's University of London, London EC1M 6BQ, United Kingdom
| | - Steven M Harwood
- From Translational Medicine and Therapeutics, William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary's University of London, London EC1M 6BQ, United Kingdom
| | - Akemichi Baba
- the Hyogo University of Health Sciences, 1-3-6 Minatojima, Chuo-ku, Kobe-shi, Hyogo 650-8530, Japan
| | - Toshio Matsuda
- the Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan, and
| | - Olivier Barbeau
- the Division of Cancer Therapeutics, Institute of Cancer Research, London SW7 3RP, United Kingdom
| | - Keith Jones
- the Division of Cancer Therapeutics, Institute of Cancer Research, London SW7 3RP, United Kingdom
| | - Suzanne A Eccles
- the Division of Cancer Therapeutics, Institute of Cancer Research, London SW7 3RP, United Kingdom
| | - Muhammad M Yaqoob
- From Translational Medicine and Therapeutics, William Harvey Research Institute, Barts and the London School of Medicine, Queen Mary's University of London, London EC1M 6BQ, United Kingdom
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7
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Lu X, Chen Z, Guo Y, Gao L, Jiang L, Li Z, Fang J. Blood-letting punctures at twelve Jing-Well points of the hand can treat cerebral ischemia in a similar manner to mannitol. Neural Regen Res 2014; 8:532-9. [PMID: 25206696 PMCID: PMC4146051 DOI: 10.3969/j.issn.1673-5374.2013.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 01/10/2013] [Indexed: 12/25/2022] Open
Abstract
A rat model of middle cerebral artery permanent occlusion was established using the modified Longa method. Successfully established model animals were treated by blood-letting puncture at twelve Jing-Well points of the hand, and/or by injecting mannitol into the caudal vein twice daily. Brain tissue was collected at 24, 48 and 72 hours after modeling, and blood was collected through the retinal vein before Evans blue was injected, approximately 1 hour prior to harvesting of brain tissue. Results showed that Evans blue leakage into brain tissue and serum nitric oxide synthase activity were significantly increased in model rats. Treatment with blood-letting punctures at twelve Jing-Well points of the hand and/or injection of mannitol into the caudal vein reduced the amount of Evans blue leakage into the brain tissue and serum nitric oxide synthase activity to varying degrees. There was no significant difference between single treatment and combined treatment. Experimental findings indicate that blood-letting punctures at twelve Jing-Well points of the hand can decrease blood-brain barrier permeability and serum nitric oxide synthase activity in rats following middle cerebral artery occlusion, and its effect is similar to that of mannitol injection alone and Jing-Well points plus mannitol injection.
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Affiliation(s)
- Xuan Lu
- Experimental Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Zelin Chen
- Experimental Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Yi Guo
- Experimental Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Liang Gao
- Experimental Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Liyuan Jiang
- Experimental Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Zhongzheng Li
- Experimental Acupuncture Research Center, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
| | - Jianqiao Fang
- Third Clinical Medical College of Zhejiang Chinese Medical University, Hangzhou 310005, Zhejiang Province, China
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8
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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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9
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Demonstration of the retention of 64Cu-ATSM in cardiac myocytes using a novel incubation chamber for screening hypoxia-dependent radiotracers. Nucl Med Commun 2013; 34:1015-22. [DOI: 10.1097/mnm.0b013e328363f25e] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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10
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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: 99] [Impact Index Per Article: 9.0] [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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11
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Sun L, Yau HY, Lau OC, Huang Y, Yao X. Effect of hydrogen peroxide and superoxide anions on cytosolic Ca2+: comparison of endothelial cells from large-sized and small-sized arteries. PLoS One 2011; 6:e25432. [PMID: 21966527 PMCID: PMC3180448 DOI: 10.1371/journal.pone.0025432] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 09/05/2011] [Indexed: 11/18/2022] Open
Abstract
We compared the Ca2+ responses to reactive oxygen species (ROS) between mouse endothelial cells derived from large-sized arteries, aortas (aortic ECs), and small-sized arteries, mesenteric arteries (MAECs). Application of hydrogen peroxide (H2O2) caused an increase in cytosolic Ca2+ levels ([Ca2+]i) in both cell types. The [Ca2+]i rises diminished in the presence of U73122, a phospholipase C inhibitor, or Xestospongin C (XeC), an inhibitor for inositol-1,4,5-trisphosphate (IP3) receptors. Removal of Ca2+ from the bath also decreased the [Ca2+]i rises in response to H2O2. In addition, treatment of endothelial cells with H2O2 reduced the [Ca2+]i responses to subsequent challenge of ATP. The decreased [Ca2+]i responses to ATP were resulted from a pre-depletion of intracellular Ca2+ stores by H2O2. Interestingly, we also found that Ca2+ store depletion was more sensitive to H2O2 treatment in endothelial cells of mesenteric arteries than those of aortas. Hypoxanthine-xanthine oxidase (HX-XO) was also found to induce [Ca2+]i rises in both types of endothelial cells, the effect of which was mediated by superoxide anions and H2O2 but not by hydroxyl radical. H2O2 contribution in HX-XO-induced [Ca2+]i rises were more significant in endothelial cells from mesenteric arteries than those from aortas. In summary, H2O2 could induce store Ca2+ release via phospholipase C-IP3 pathway in endothelial cells. Resultant emptying of intracellular Ca2+ stores contributed to the reduced [Ca2+]i responses to subsequent ATP challenge. The [Ca2+]i responses were more sensitive to H2O2 in endothelial cells of small-sized arteries than those of large-sized arteries.
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Affiliation(s)
- Lei Sun
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ho-Yan Yau
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - On-Chai Lau
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Yu Huang
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoqiang Yao
- School of Biomedical Sciences and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong, China
- * E-mail:
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12
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Sandoval KE, Witt KA. Blood-brain barrier tight junction permeability and ischemic stroke. Neurobiol Dis 2008; 32:200-19. [PMID: 18790057 DOI: 10.1016/j.nbd.2008.08.005] [Citation(s) in RCA: 739] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 07/29/2008] [Accepted: 08/10/2008] [Indexed: 01/01/2023] Open
Abstract
The blood-brain barrier (BBB) is formed by the endothelial cells of cerebral microvessels, providing a dynamic interface between the peripheral circulation and the central nervous system. The tight junctions (TJs) between the endothelial cells serve to restrict blood-borne substances from entering the brain. Under ischemic stroke conditions decreased BBB TJ integrity results in increased paracellular permeability, directly contributing to cerebral vasogenic edema, hemorrhagic transformation, and increased mortality. This loss of TJ integrity occurs in a phasic manner, which is contingent on several interdependent mechanisms (ionic dysregulation, inflammation, oxidative and nitrosative stress, enzymatic activity, and angiogenesis). Understanding the inter-relation of these mechanisms is critical for the development of new therapies. This review focuses on those aspects of ischemic stroke impacting BBB TJ integrity and the principle regulatory pathways, respective to the phases of paracellular permeability.
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Affiliation(s)
- Karin E Sandoval
- Department of Pharmaceutical Sciences, School of Pharmacy, Southern Illinois University Edwardsville, Edwardsville, IL 62026, USA
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13
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Dikalov S, Griendling KK, Harrison DG. Measurement of reactive oxygen species in cardiovascular studies. Hypertension 2007; 49:717-27. [PMID: 17296874 PMCID: PMC1993891 DOI: 10.1161/01.hyp.0000258594.87211.6b] [Citation(s) in RCA: 379] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Sergey Dikalov
- Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA 30322, USA
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Mozaffari MS, Patel C, Schaffer SW. Mechanisms Underlying Afterload-Induced Exacerbation of Myocardial Infarct Size. Hypertension 2006; 47:912-9. [PMID: 16505194 DOI: 10.1161/01.hyp.0000209940.65941.46] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
One consequence of elevated afterload pressure is the activation of the angiotensin II type 1 receptor and nonspecific cation channels with subsequent Ca
2+
accumulation via the Na
+
/H
+
-Na
+
/Ca
2+
exchanger combination and the T-type or L-type Ca
2+
channels. Intracellular Ca
2+
overload is cytotoxic, in part, by inducing the mitochondrial permeability transition (MPT) pore. Therefore, we tested the hypotheses that: (1) increased afterload pressure worsens myocardial ischemia-reperfusion injury in healthy heart, (2) the Na
+
/H
+
-Na
+
/Ca
2+
exchanger combination and both the T-type and L-type Ca
2+
channels are involved in the exacerbating impact of high afterload pressure on infarct size, and (3) elevated afterload enhances infarct size in part via the MPT pore. Accordingly, the effect of candesartan (angiotensin II type 1 receptor antagonist), cariporide (inhibitor of the Na
+
/H
+
exchanger), mibefradil (T-type Ca
2+
channel blocker), diltiazem (L-type Ca
2+
channel blocker), or cyclosporine A (inhibitor of MPT pore) were examined. The elevation in afterload pressure from 80 to 160 cmH
2
O increased baseline myocardial performance but caused larger infarcts and worsened recovery of mechanical function after ischemia reperfusion. Whereas mibefradil abrogated the effect of high afterload pressure on infarct size, the other agents reduced infarct size at both afterload pressures. Hearts exposed to mibefradil, diltiazem, or cariporide displayed greater functional recovery than those exposed to candesartan or cyclosporine A, revealing that an uncoupling exists between reduced cell death and recovery of mechanical function of the viable portions of the myocardium. The data also uncovered an important link between pressure-mediated exacerbation of infarct size and T-type Ca
2+
channel activity.
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Affiliation(s)
- Mahmood S Mozaffari
- Department of Oral Biology and Maxillofacial Pathology, Medical College of Georgia School of Dentistry, Augusta, GA 30912, USA.
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15
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Li L, Mamputu JC, Wiernsperger N, Renier G. Signaling pathways involved in human vascular smooth muscle cell proliferation and matrix metalloproteinase-2 expression induced by leptin: inhibitory effect of metformin. Diabetes 2005; 54:2227-34. [PMID: 15983226 DOI: 10.2337/diabetes.54.7.2227] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Accumulating evidence suggests that high concentrations of leptin observed in obesity and diabetes may contribute to their adverse effects on cardiovascular health. Metformin monotherapy is associated with reduced macrovascular complications in overweight patients with type 2 diabetes. It is uncertain whether such improvement in the cardiovascular outcome is related to specific vasculoprotective effects of this drug. In the present study, we determined the effect of leptin on human aortic smooth muscle cell (HASMC) proliferation and matrix metalloproteinase (MMP)-2 expression, the signaling pathways mediating these effects, and the modulatory effect of metformin on these parameters. Incubation of HASMCs with leptin enhanced the proliferation and MMP-2 expression in these cells and increased the generation of intracellular reactive oxygen species (ROS). These effects were abolished by vitamin E. Inhibition of NAD(P)H oxidase and protein kinase C (PKC) suppressed the effect of leptin on ROS production. In HASMCs, leptin induced PKC, extracellular signal-regulated kinase (ERK)1/2, and nuclear factor-kappaB (NF-kappaB) activation and inhibition of these signaling pathways abrogated HASMC proliferation and MMP-2 expression induced by this hormone. Treatment of HASMCs with metformin decreased leptin-induced ROS production and activation of PKC, ERK1/2, and NF-kappaB. Metformin also inhibited the effect of leptin on HASMC proliferation and MMP-2 expression. Overall, these results demonstrate that leptin induced HASMC proliferation and MMP-2 expression through a PKC-dependent activation of NAD(P)H oxidase with subsequent activation of the ERK1/2/NF-kappaB pathways and that therapeutic metformin concentrations effectively inhibit these biological effects. These results suggest a new mechanism by which metformin may improve cardiovascular outcome in patients with diabetes.
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Affiliation(s)
- Ling Li
- CHUM Research Centre, Notre-Dame Hospital, 1560 Sherbrooke St. East, Room Y-3622, Montreal, Quebec, Canada H2L 4M1
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16
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Zhang S, Remillard CV, Fantozzi I, Yuan JXJ. ATP-induced mitogenesis is mediated by cyclic AMP response element-binding protein-enhanced TRPC4 expression and activity in human pulmonary artery smooth muscle cells. Am J Physiol Cell Physiol 2004; 287:C1192-201. [PMID: 15229105 DOI: 10.1152/ajpcell.00158.2004] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Extracellular ATP and intracellular cyclic AMP response element-binding protein (CREB, a transcription factor) promote cell proliferation in many cell types. The canonical transient receptor potential (TRPC) channels, which putatively participate in forming store- and receptor-operated Ca2+ channels, have been implicated in the pulmonary vascular remodeling processes. A link between extracellular ATP, CREB activation, and TRPC4 channel expression and activity has not been shown in human pulmonary artery smooth muscle cells (PASMC). Long-term (24-48 h) treatment of human PASMC with a low dose (100 microM) of ATP, which did not trigger a transient rise in free cytosolic Ca2+ concentration ([Ca2+]i) when applied acutely to the cells, caused marked increases in CREB phosphorylation and TRPC4 protein expression. The time course indicated that the ATP-mediated CREB phosphorylation preceded TRPC4 upregulation, whereas transfection of a nonphosphorylatable CREB mutant abolished ATP-mediated TRPC4 expression. Furthermore, treatment of human PASMC with ATP also enhanced the amplitude of capacitative Ca2+ entry (CCE) induced by passive store depletion, whereas the small interfering RNA specifically targeting TRPC4 attenuated ATP-mediated increases in TRPC4 expression and CCE amplitude and inhibited ATP-induced PASMC proliferation. These data suggest that low-dose ATP exerts part of its mitogenic effect in human PASMC via CREB-mediated upregulation of TRPC4 channel expression and activity and the subsequent increase in CCE and [Ca2+]i.
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Affiliation(s)
- Shen Zhang
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of California, San Diego, La Jolla, California 92093-0725, USA.
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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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Fantozzi I, Zhang S, Platoshyn O, Remillard CV, Cowling RT, Yuan JXJ. Hypoxia increases AP-1 binding activity by enhancing capacitative Ca2+ entry in human pulmonary artery endothelial cells. Am J Physiol Lung Cell Mol Physiol 2003; 285:L1233-45. [PMID: 12909593 DOI: 10.1152/ajplung.00445.2002] [Citation(s) in RCA: 150] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Activating protein (AP)-1 transcription factors modulate expression of genes involved in cell proliferation and migration. Chronic hypoxia increases pulmonary artery smooth muscle cell proliferation by upregulating AP-1-responsive genes encoding for endothelium-derived vasoactive and mitogenic factors implicated in pulmonary hypertension development. The expression of AP-1 transcription factors is sensitive to changes in cytosolic free [Ca2+] ([Ca2+]cyt). Capacitative Ca2+ entry (CCE) via store-operated Ca2+ channels (SOC) is an important mechanism for raising [Ca2+]cyt in pulmonary artery endothelial cells (PAEC). Using combined molecular biological, fluorescence microscopy, and biophysical approaches, we examined the effect of chronic hypoxia (3% O2, 72 h) on AP-1 DNA binding activity, CCE, and transient receptor potential (TRP) gene expression in human (h) PAEC. EMSA showed that AP-1 binding to hPAEC nuclear protein extracts was significantly enhanced by hypoxia, the increase being dependent on store-operated Ca2+ influx and sensitive to La3+, an SOC inhibitor. Hypoxia also increased basal [Ca2+]cyt, the amount of CCE produced by store depletion with cyclopiazonic acid, and the amplitude of SOC-mediated currents (ISOC). The increases of CCE amplitude and ISOC current density by hypoxia were paralleled by enhanced TRPC4 mRNA and protein expression. Hypoxia-enhanced CCE and TRPC4 expression were also attenuated by La3+. These data suggest that hypoxia increases AP-1 binding activity by enhancing Ca2+ influx via La3+-sensitive TRP-encoded SOC channels in hPAEC. The Ca2+-mediated increase in AP-1 binding may play an important role in upregulating AP-1-responsive gene expression, in stimulating pulmonary vascular cell proliferation and, ultimately, in pulmonary vascular remodeling in patients with hypoxia-mediated pulmonary hypertension.
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Affiliation(s)
- Ivana Fantozzi
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, School of Medicine, University of California, San Diego, CA 92103-8382, USA
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Kimura C, Oike M, Ohnaka K, Nose Y, Ito Y. Constitutive nitric oxide production in bovine aortic and brain microvascular endothelial cells: a comparative study. J Physiol 2003; 554:721-30. [PMID: 14617679 PMCID: PMC1664799 DOI: 10.1113/jphysiol.2003.057059] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Vascular endothelium constitutively generates nitric oxide (NO) in large vessels and induces a relaxation of smooth muscle cells. However, little is known about the production of NO in microvessels, where smooth muscle layers are thin or absent. In this study, we have compared the constitutive production of NO in bovine brain microvascular endothelial cells (BBECs) with that in bovine aortic endothelial cells (BAECs). ATP, acetylcholine (ACh) and A23187 induced Ca(2+) transients both in BBECs and BAECs. In contrast, although ATP and A23187 evoked a similar degree of [Ca(2+)](i) increase in both types of cell, they failed to induce NO production in BBECs, as measured with an NO-sensitive fluorescent dye DAF-2, whereas in BAECs there was an increase in DAF-2 fluorescence. Hypotonic stress induced ATP release and subsequent NO production in BAECs, but not in BBECs. We have developed an in vitro model vessel system that consists of aortic smooth muscle cells embedded in a collagen gel lattice and overlaid with endothelial cells. Precontracted gels showed relaxation in response to ACh, when BAECs were overlaid. However, ACh-induced relaxation was not observed in BBEC-overlaid gels. Expression of eNOS protein as well as cellular uptake of l-[(3)H]arginine were significantly lower in BBECs than in BAECs. These results indicate that Ca(2+)-dependent NO production is at an undetectable level in BBEC, for which at least two factors, i.e. low levels of eNOS expression and l-arginine uptake, are responsible.
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Affiliation(s)
- Chiwaka Kimura
- Department of Pharmacology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Casillan AJ, Gonzalez NC, Johnson JS, Steiner DRS, Wood JG. Mesenteric microvascular inflammatory responses to systemic hypoxia are mediated by PAF and LTB4. J Appl Physiol (1985) 2003; 94:2313-22. [PMID: 12598480 DOI: 10.1152/japplphysiol.00047.2002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Systemic hypoxia produces a rapid microvascular inflammatory response characterized by increased reactive oxygen species (ROS) levels, leukocyte-endothelial adherence and emigration, and increased vascular permeability. The lipid inflammatory mediator leukotriene B(4) (LTB(4)) is involved in the early hypoxia-induced responses (ROS generation and leukocyte adherence). Whether other lipid inflammatory mediators participate in this phenomenon is not known. The objective of these experiments was to study the role of platelet-activating factor (PAF) in the microvascular inflammatory response to hypoxia and its potential interactions with LTB(4) in this response. Intravital microscopy was used to examine mesenteric venules of anesthetized rats. We found that WEB-2086, a PAF receptor antagonist, completely prevented the increase in ROS levels and leukocyte adherence during a brief reduction in inspired Po(2) to anesthetized rats; administration of either WEB-2086 or the LTB(4) antagonist LTB(4)-DMA attenuated leukocyte emigration and the increase in vascular permeability to the same extent during prolonged systemic hypoxia in conscious rats. Furthermore, no additive effect was observed in either response when both antagonists were administered simultaneously. This study demonstrates a role for PAF in the rapid microvascular inflammatory response to hypoxia, as well as contributions of PAF and LTB(4) to the slowly developing responses observed during sustained hypoxia. The incomplete blockade of the hypoxia-induced increases in vascular permeability and leukocyte emigration by combined administration of both antagonists indicates that factors in addition to LTB(4) and PAF participate in these phenomena.
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Affiliation(s)
- Alfred J Casillan
- Department of Molecular and Integrative Physiology, The University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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21
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Kimura C, Cheng W, Hisadome K, Wang YP, Koyama T, Karashima Y, Oike M, Ito Y. Superoxide anion impairs contractility in cultured aortic smooth muscle cells. Am J Physiol Heart Circ Physiol 2002; 283:H382-90. [PMID: 12063312 DOI: 10.1152/ajpheart.00574.2001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the effects of superoxide anion (O) generated by xanthine plus xanthine oxidase (X/XO) on the intracellular Ca(2+) concentration ([Ca(2+)](i)) and muscle contractility in cultured bovine aortic smooth muscle cells (BASMC). Cells were grown on collagen-coated dish for the measurement of [Ca(2+)](i). Pretreatment with X/XO inhibited ATP-induced Ca(2+) transient and Ca(2+) release-activated Ca(2+) entry (CRAC) after thapsigargin-induced store depletion, both of which were reversed by superoxide dismutase (SOD). In contrast, Ca(2+) transients induced by high-K(+) solution and Ca(2+) ionophore A-23187 were not affected by X/XO. BASMC-embedded collagen gel lattice, which was pretreated with xanthine alone, showed contraction in response to ATP, thapsigargin, high-K(+) solution, and A-23187. Pretreatment of the gel with X/XO impaired gel contraction not only by ATP and thapsigargin, but also by high-K(+) solution and A-23187. The X/XO-treated gel showed normal contraction; however, when SOD was present during the pretreatment period. These results indicate that O(2)(-) attenuates smooth muscle contraction by impairing CRAC, ATP-induced Ca(2+) transient, and Ca(2+) sensitivity in BASMC.
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MESH Headings
- Adenosine Triphosphate/pharmacology
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/physiology
- Calcium/metabolism
- Cattle
- Cells, Cultured
- Collagen/physiology
- Enzyme Inhibitors/pharmacology
- Gels
- Imidazoles
- Intracellular Fluid/metabolism
- Ionophores/pharmacology
- Luminescent Measurements
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Potassium/pharmacology
- Pyrazines
- Superoxide Dismutase/metabolism
- Superoxides/analysis
- Superoxides/metabolism
- Superoxides/pharmacology
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
- Xanthine/metabolism
- Xanthine Oxidase/metabolism
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Affiliation(s)
- Chiwaka Kimura
- Department of Pharmacology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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Brown RC, Davis TP. Calcium modulation of adherens and tight junction function: a potential mechanism for blood-brain barrier disruption after stroke. Stroke 2002; 33:1706-11. [PMID: 12053015 DOI: 10.1161/01.str.0000016405.06729.83] [Citation(s) in RCA: 209] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND This review deals with the role of calcium in endothelial cell junctions of the blood-brain barrier (BBB). Calcium is critical for adherens junction function, but it appears that calcium is also important in regulating tight junction function necessary for the barrier characteristics of cerebral microvessels. SUMMARY OF REVIEW The BBB is critical for brain homeostasis and is located at the cerebral microvessel endothelial cells. These endothelial cells maintain their barrier characteristics via cell-cell contacts made up of adherens and tight junctions. Adherens junctions are calcium dependent; recent evidence suggests that calcium also affects tight junctions. After stroke, there is a disruption of the BBB. Interfering with calcium flux under hypoxic conditions can prevent BBB breakdown. Calcium may alter BBB junction integrity by a number of different signal transduction cascades, as well as via direct interaction of calcium ions with junction proteins. It remains to be determined whether clinical use of calcium channel antagonists is a viable means to reduce BBB disruption after stroke. CONCLUSIONS With the widespread use of calcium channel blockers as clinical treatments for hypertension, which is a risk factor for stroke, the exact role of calcium in modulating BBB integrity needs to be elucidated.
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Affiliation(s)
- Rachel C Brown
- Department of Pharmacology, University of Arizona College of Medicine, Tucson 85724-5050, USA
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Mark KS, Davis TP. Cerebral microvascular changes in permeability and tight junctions induced by hypoxia-reoxygenation. Am J Physiol Heart Circ Physiol 2002; 282:H1485-94. [PMID: 11893586 PMCID: PMC3918411 DOI: 10.1152/ajpheart.00645.2001] [Citation(s) in RCA: 280] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cerebral microvessel endothelial cells that form the blood-brain barrier (BBB) have tight junctions (TJ) that are critical for maintaining brain homeostasis and low permeability. Both integral (claudin-1 and occludin) and membrane-associated zonula occluden-1 and -2 (ZO-1 and ZO-2) proteins combine to form these TJ complexes that are anchored to the cytoskeletal architecture (actin). Disruptions of the BBB have been attributed to hypoxic conditions that occur with ischemic stroke, pathologies of decreased perfusion, and high-altitude exposure. The effects of hypoxia and posthypoxic reoxygenation in cerebral microvasculature and corresponding cellular mechanisms involved in disrupting the BBB remain unclear. This study examined hypoxia and posthypoxic reoxygenation effects on paracellular permeability and changes in actin and TJ proteins using primary bovine brain microvessel endothelial cells (BBMEC). Hypoxia induced a 2.6-fold increase in [(14)C]sucrose, a marker of paracellular permeability. This effect was significantly reduced (~58%) with posthypoxic reoxygenation. After hypoxia and posthypoxic reoxygenation, actin expression was increased (1.4- and 2.3-fold, respectively). Whereas little change was observed in TJ protein expression immediately after hypoxia, a twofold increase in expression was seen with posthypoxic reoxygenation. Furthermore, immunofluorescence studies showed alterations in occludin, ZO-1, and ZO-2 protein localization during hypoxia and posthypoxic reoxygenation that correlate with the observed changes in BBMEC permeability. The results of this study show hypoxia-induced changes in paracellular permeability may be due to perturbation of TJ complexes and that posthypoxic reoxygenation reverses these effects.
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Affiliation(s)
- Karen S Mark
- Department of Pharmacology, University of Arizona College of Medicine, Tucson, Arizona 85724-5050, USA
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Paschen W, Frandsen A. Endoplasmic reticulum dysfunction--a common denominator for cell injury in acute and degenerative diseases of the brain? J Neurochem 2001; 79:719-25. [PMID: 11723164 DOI: 10.1046/j.1471-4159.2001.00623.x] [Citation(s) in RCA: 190] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Various physiological, biochemical and molecular biological disturbances have been put forward as mediators of neuronal cell injury in acute and chronic pathological states of the brain such as ischemia, epileptic seizures and Alzheimer's or Parkinson's disease. These include over-activation of glutamate receptors, a rise in cytoplasmic calcium activity and mitochondrial dysfunction. The possible involvement of the endoplasmic reticulum (ER) dysfunction in this process has been largely neglected until recently, although the ER plays a central role in important cell functions. Not only is the ER involved in the control of cellular calcium homeostasis, it is also the subcellular compartment in which the folding and processing of membrane and secretory proteins takes place. The fact that blocking of these processes is sufficient to cause cell damage indicates that they are crucial for normal cell functioning. This review presents evidence that ER function is disturbed in many acute and chronic diseases of the brain. The complex processes taken place in this subcellular compartment are however, affected in different ways in various disorders; whereas the ER-associated degradation of misfolded proteins is affected in Parkinson's disease, it is the unfolded protein response which is down-regulated in Alzheimer's disease and the ER calcium homeostasis that is disturbed in ischemia. Studying the consequences of the observed deteriorations of ER function and identifying the mechanisms causing ER dysfunction in these pathological states of the brain will help to elucidate whether neurodegeneration is indeed caused by these disturbances, and will help to facilitate the search for drugs capable of blocking the pathological process directly at an early stage.
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Affiliation(s)
- W Paschen
- Department of Experimental Neurology, Max-Planck-Institute for Neurological Research, Cologne, Germany.
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Carlotti Junior CG, Colli BO, Kazuo JY. Avaliação da isquemia cerebral pela respiração mitocondrial: modelo experimental. ARQUIVOS DE NEURO-PSIQUIATRIA 2001. [DOI: 10.1590/s0004-282x2001000300011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A isquemia cerebral acontece em várias doenças. Um dos fatores críticos para a recuperação de um paciente é a duração do processo isquêmico. A atividade cerebral depende do suprimento de energia, isto sugere que o estudo da função mitocondrial pode ser utilizado para a avaliação do dano neuronal. O objetivo deste trabalho foi o de estudar a respiração mitocondrial pela oclusão da artéria cerebral média esquerda pela técnica do fio intraluminal. Ratos da raça Wistar foram subdivididos em 4 grupos: controle e 15, 30 e 60 minutos de oclusão. Os resultados mostraram que não há diferença estatisticamente significativa entre o grupo de 15 minutos e o grupo controle. O grupo de 30 minutos teve diminuição do estado III da respiração mitocondrial comparado com o grupo controle. O grupo de 60 minutos teve diminuição dos estados III e IV comparados com o grupo controle. A respiração mitocondrial permitiu uma avaliação efetiva e precoce do processo isquêmico focal no cérebro do rato.
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