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Astrocyte Specific Remodeling of Plasmalemmal Cholesterol Composition by Ketamine Indicates a New Mechanism of Antidepressant Action. Sci Rep 2019; 9:10957. [PMID: 31358895 PMCID: PMC6662760 DOI: 10.1038/s41598-019-47459-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/15/2019] [Indexed: 12/20/2022] Open
Abstract
Ketamine is an antidepressant with rapid therapeutic onset and long-lasting effect, although the underlying mechanism(s) remain unknown. Using FRET-based nanosensors we found that ketamine increases [cAMP]i in astrocytes. Membrane capacitance recordings, however, reveal fundamentally distinct mechanisms of effects of ketamine and [cAMP]i on vesicular secretion: a rise in [cAMP]i facilitated, whereas ketamine inhibited exocytosis. By directly monitoring cholesterol-rich membrane domains with a fluorescently tagged cholesterol-specific membrane binding domain (D4) of toxin perfringolysin O, we demonstrated that ketamine induced cholesterol redistribution in the plasmalemma in astrocytes, but neither in fibroblasts nor in PC 12 cells. This novel mechanism posits that ketamine affects density and distribution of cholesterol in the astrocytic plasmalemma, consequently modulating a host of processes that may contribute to ketamine's rapid antidepressant action.
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Chang CW, Chiang CW, Jackson MB. Fusion pores and their control of neurotransmitter and hormone release. J Gen Physiol 2017; 149:301-322. [PMID: 28167663 PMCID: PMC5339513 DOI: 10.1085/jgp.201611724] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 01/06/2017] [Accepted: 01/19/2017] [Indexed: 11/20/2022] Open
Abstract
Chang et al. review fusion pore structure and dynamics and discuss the implications for hormone and neurotransmitter release Ca2+-triggered exocytosis functions broadly in the secretion of chemical signals, enabling neurons to release neurotransmitters and endocrine cells to release hormones. The biological demands on this process can vary enormously. Although synapses often release neurotransmitter in a small fraction of a millisecond, hormone release can be orders of magnitude slower. Vesicles usually contain multiple signaling molecules that can be released selectively and conditionally. Cells are able to control the speed, concentration profile, and content selectivity of release by tuning and tailoring exocytosis to meet different biological demands. Much of this regulation depends on the fusion pore—the aqueous pathway by which molecules leave a vesicle and move out into the surrounding extracellular space. Studies of fusion pores have illuminated how cells regulate secretion. Furthermore, the formation and growth of fusion pores serve as a readout for the progress of exocytosis, thus revealing key kinetic stages that provide clues about the underlying mechanisms. Herein, we review the structure, composition, and dynamics of fusion pores and discuss the implications for molecular mechanisms as well as for the cellular regulation of neurotransmitter and hormone release.
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Affiliation(s)
- Che-Wei Chang
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705
| | - Chung-Wei Chiang
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705
| | - Meyer B Jackson
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705
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Tang KS. Protective effect of arachidonic acid and linoleic acid on 1-methyl-4-phenylpyridinium-induced toxicity in PC12 cells. Lipids Health Dis 2014; 13:197. [PMID: 25522984 PMCID: PMC4320435 DOI: 10.1186/1476-511x-13-197] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 12/01/2014] [Indexed: 01/13/2023] Open
Abstract
Background Parkinson’s disease is a neurodegenerative disorder that is being characterized by the progressive loss of dopaminergic neurons of the nigrostriatal pathway in the brain. The protective effect of omega-6 fatty acids is unclear. There are lots of contradictions in the literature with regard to the cytoprotective role of arachidonic acid. To date, there is no solid evidence that shows the protective role of omega-6 fatty acids in Parkinson’s disease. In the current study, the potential of two omega-6 fatty acids (i.e. arachidonic acid and linoleic acid) in alleviating 1-methyl-4-phenylpyridinium (MPP+)-induced cytotoxicity in PC12 cells was examined. Methods Cultured PC12 cells were either treated with MPP+ alone or co-treated with one of the omega-6 fatty acids for 1 day. Cell viability was then assessed by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results Cells treated with 500 μM MPP+ for a day reduced cell viability to ~70% as compared to control group. Linoleic acid (50 and 100 μM) significantly reduced MPP+-induced cell death back to ~85-90% of the control value. The protective effect could be mimicked by arachidonic acid, but not by ciglitazone. Conclusions Both linoleic acid and arachidonic acid are able to inhibit MPP+-induced toxicity in PC12 cells. The protection is not mediated via peroxisome proliferator-activated receptor gamma (PPAR-γ). Overall, the results suggest the potential role of omega-6 fatty acids in the treatment of Parkinson’s disease.
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Affiliation(s)
- Kim San Tang
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia.
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Wang N, Lee AK, Yan L, Simpson MR, Tse A, Tse FW. Granule matrix property and rapid “kiss-and-run” exocytosis contribute to the different kinetics of catecholamine release from carotid glomus and adrenal chromaffin cells at matched quantal size. Can J Physiol Pharmacol 2012; 90:791-801. [DOI: 10.1139/y2012-040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Catecholamine-containing small dense core granules (SDCGs, vesicular diameter of ∼100 nm) are prominent in carotid glomus (chemosensory) cells and some neurons, but the release kinetics from individual SDCGs has not been studied in detail. In this study, we compared the amperometric signals from glomus cells with those from adrenal chromaffin cells, which also secrete catecholamine but via large dense core granules (LDCGs, vesicular diameter of ∼200–250 nm). When exocytosis was triggered by whole-cell dialysis (which raised the concentration of intracellular Ca2+ ([Ca2+]i) to ∼0.5 µmol/L), the proportion of the type of signal that represents a flickering fusion pore was 9-fold higher for glomus cells. Yet, at the same range of quantal size (Q, the total amount of catecholamine that can be released from a granule), the kinetics of every phase of the amperometric spike signals from glomus cells was faster. Our data indicate that the last phenomenon involved at least 2 mechanisms: (i) the granule matrix of glomus cells can supply a higher concentration of free catecholamine during exocytosis; (ii) a modest elevation of [Ca2+]i triggers a form of rapid “kiss-and-run” exocytosis, which is very prevalent among glomus SDCGs and leads to incomplete release of their catecholamine content (and underestimation of their Q value).
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Affiliation(s)
- Nan Wang
- Department of Pharmacology, 9–12 Medical Sciences Building, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Andy K. Lee
- Department of Pharmacology, 9–12 Medical Sciences Building, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Lei Yan
- Centre for Neuroscience, 9–12 Medical Sciences Building, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Michael R. Simpson
- Centre for Neuroscience, 9–12 Medical Sciences Building, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Amy Tse
- Department of Pharmacology, 9–12 Medical Sciences Building, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Centre for Neuroscience, 9–12 Medical Sciences Building, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Frederick W. Tse
- Department of Pharmacology, 9–12 Medical Sciences Building, University of Alberta, Edmonton, AB T6G 2H7, Canada
- Centre for Neuroscience, 9–12 Medical Sciences Building, University of Alberta, Edmonton, AB T6G 2H7, Canada
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Regulation of the immune response and inflammation by histamine and histamine receptors. J Allergy Clin Immunol 2011; 128:1153-62. [PMID: 21824648 DOI: 10.1016/j.jaci.2011.06.051] [Citation(s) in RCA: 207] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 06/01/2011] [Accepted: 06/23/2011] [Indexed: 02/04/2023]
Abstract
Histamine is a biogenic amine with extensive effects on many cell types, including important immunologic cells, such as antigen-presenting cells, natural killer cells, epithelial cells, and T and B lymphocytes. Histamine and its 4 receptors represent a complex system of immunoregulation with distinct effects dependent on receptor subtypes and their differential expression. These are influenced by the stage of cell differentiation, as well as microenvironmental influences, leading to the selective recruitment of effector cells into tissue sites accompanied by effects on cellular maturation, activation, polarization, and effector functions, which lead to tolerogenic or proinflammatory responses. In this review we discuss the regulation of histamine secretion, receptor expression, and differential activation of cells within both the innate and adaptive immune responses. It is clear that the effects of histamine on immune homeostasis are dependent on the expression and activity of the 4 currently known histamine receptors, and we also recognize that 100 years after the original identification of this biogenic amine, we still do not fully understand the complex regulatory interactions between histamine and the host immune response to everyday microbial and environmental challenges.
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van Kempen GTH, vanderLeest H, van den Berg R, Eilers P, Westerink R. Three distinct modes of exocytosis revealed by amperometry in neuroendocrine cells. Biophys J 2011; 100:968-77. [PMID: 21320441 PMCID: PMC3037570 DOI: 10.1016/j.bpj.2011.01.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 12/30/2010] [Accepted: 01/04/2011] [Indexed: 11/19/2022] Open
Abstract
Neurotransmission requires Ca(2+)-dependent release of secretory products through fusion pores that open and reclose (partial membrane distention) or open irreversibly (complete membrane distention). It has been challenging to distinguish between these release modes; however, in the work presented here, we were able to deduce different modes of depolarization-evoked exocytosis in neuroendocrine chromaffin and PC12 cells solely by analyzing amperometric recordings. After we determined the quantal size (Q), event half-width (t(50)), event amplitude (I(peak)), and event decay time constant (τ(decay)), we fitted scatter plots of log-transformed data with a mixture of one- and two-dimensional Gaussian distributions. Our analysis revealed three distinct and differently shaped clusters of secretory events, likely corresponding to different modes of exocytosis. Complete membrane distention, through fusion pores of widely varying conductances, accounted for 70% of the total amount of released catecholamine. Two different kinds of partial membrane distention (kiss-and-run and kiss-and-stay exocytosis), characterized by mode-specific fusion pores with unitary conductances, accounted for 20% and 10%, respectively. These results show that our novel one- and two-dimensional analysis of amperometric data reveals new release properties and enables one to distinguish at least three different modes of exocytosis solely by analyzing amperometric recordings.
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Affiliation(s)
- G. Th. H. van Kempen
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - H.T. vanderLeest
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - R.J. van den Berg
- Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - P. Eilers
- Department of Biostatistics, Erasmus University, Rotterdam, The Netherlands
| | - R.H.S. Westerink
- Neurotoxicology Research Group, Toxicology Division, Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands
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Influence of cholesterol on catecholamine release from the fusion pore of large dense core chromaffin granules. J Neurosci 2010; 30:3904-11. [PMID: 20237261 DOI: 10.1523/jneurosci.4000-09.2010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Changes in cellular cholesterol can affect exocytosis, but the influence of cholesterol in fusion pore kinetics is unclear. Using carbon fiber amperometry, we monitored quantal catecholamine release from rat chromaffin cells. To bypass any possible effect of cholesterol perturbation on ion channels or the colocalization of voltage-gated Ca(2+) channels with sites of exocytosis, exocytosis was stimulated via uniform elevation of cytosolic [Ca(2+)] (with whole-cell dialysis of a Ca(2+)-buffered solution). Under this condition, alterations of cellular cholesterol affected neither the mean number of amperometric events triggered per cell nor their quantal size and the kinetics of their main spike (which reflects the rapid release during and after rapid fusion pore dilation). In contrast, the reduction of cellular cholesterol shortened the "prespike foot" signals (which reflect the leakage of catecholamine via a semi-stable fusion pore) and reduced the proportion of "stand-alone foot" signals (which reflect the release via a flickering fusion pore that may close before it dilates significantly), whereas an oversupply of cholesterol had opposite effects. Acute extraction of cholesterol from the cytosol (via whole-cell dialysis of a cholesterol extractor) also shortened the prespike foot signals and reduced the proportion of stand-alone foot signals, but acute extracellular application of cholesterol extractor or "soluble" cholesterol had no effect. Our data raise the possibility that cholesterol molecules, particularly those in the cytoplasmic leaflet, helps to constrain the narrow waistline of a semi-stable fusion pore while it is flickering or before it starts to dilate rapidly.
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Zhang J, Xue R, Ong WY, Chen P. Roles of cholesterol in vesicle fusion and motion. Biophys J 2009; 97:1371-80. [PMID: 19720025 DOI: 10.1016/j.bpj.2009.06.025] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2009] [Revised: 06/18/2009] [Accepted: 06/22/2009] [Indexed: 12/01/2022] Open
Abstract
Although it is well established that exocytosis of neurotransmitters and hormones is highly regulated by numerous secretory proteins, such as SNARE proteins, there is an increasing appreciation of the importance of the chemophysical properties and organization of membrane lipids to various aspects of the exocytotic program. Based on amperometric recordings by carbon fiber microelectrodes, we show that deprivation of membrane cholesterol by methyl-beta-cyclodextrin not only inhibited the extent of membrane depolarization-induced exocytosis, it also adversely affected the kinetics and quantal size of vesicle fusion in neuroendocrine PC12 cells. In addition, total internal fluorescence microscopy studies revealed that cholesterol depletion impaired vesicle docking and trafficking, which are believed to correlate with the dynamics of exocytosis. Furthermore, we found that free cholesterol is able to directly trigger vesicle fusion, albeit with less potency and slower kinetics as compared to membrane depolarization stimulation. These results underscore the versatile roles of cholesterol in facilitating exocytosis.
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Affiliation(s)
- Jing Zhang
- Division of Bioengineering, Nanyang Technological University, Singapore
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