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Lucas-Osma AM, Li Y, Murray K, Lin S, Black S, Stephens MJ, Ahn AH, Heckman CJ, Fenrich KK, Fouad K, Bennett DJ. 5-HT 1D receptors inhibit the monosynaptic stretch reflex by modulating C-fiber activity. J Neurophysiol 2019; 121:1591-1608. [PMID: 30625007 DOI: 10.1152/jn.00805.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The monosynaptic stretch reflex (MSR) plays an important role in feedback control of movement and posture but can also lead to unstable oscillations associated with tremor and clonus, especially when increased with spinal cord injury (SCI). To control the MSR and clonus after SCI, we examined how serotonin regulates the MSR in the sacrocaudal spinal cord of rats with and without a chronic spinal transection. In chronic spinal rats, numerous 5-HT receptor agonists, including zolmitriptan, methylergonovine, and 5-HT, inhibited the MSR with a potency highly correlated to their binding affinity to 5-HT1D receptors and not other 5-HT receptors. Selective 5-HT1D receptor antagonists blocked this agonist-induced inhibition, although antagonists alone had no action, indicating a lack of endogenous or constitutive receptor activity. In normal uninjured rats, the MSR was likewise inhibited by 5-HT, but at much higher doses, indicating a supersensitivity after SCI. This supersensitivity resulted from the loss of the serotonin transporter SERT with spinal transection, because normal and injured rats were equally sensitive to 5-HT after SERT was blocked or to agonists not transported by SERT (zolmitriptan). Immunolabeling revealed that the 5-HT1D receptor was confined to superficial lamina of the dorsal horn, colocalized with CGRP-positive C-fibers, and eliminated by dorsal rhizotomy. 5-HT1D receptor labeling was not found on large proprioceptive afferents or α-motoneurons of the MSR. Thus serotonergic inhibition of the MSR acts indirectly by modulating C-fiber activity, opening up new possibilities for modulating reflex function and clonus via pain-related pathways. NEW & NOTEWORTHY Brain stem-derived serotonin potently inhibits afferent transmission in the monosynaptic stretch reflex. We show that serotonin produces this inhibition exclusively via 5-HT1D receptors, and yet these receptors are paradoxically mostly confined to C-fibers. This suggests that serotonin acts by gating of C-fiber activity, which in turn modulates afferent transmission to motoneurons. We also show that the classic supersensitivity to 5-HT after spinal cord injury results from a loss of SERT, and not 5-HT1D receptor plasticity.
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Affiliation(s)
- Ana M Lucas-Osma
- Neuroscience and Mental Health Institute and Faculty of Rehabilitation Medicine, University of Alberta , Edmonton, Alberta , Canada
| | - Yaqing Li
- Neuroscience and Mental Health Institute and Faculty of Rehabilitation Medicine, University of Alberta , Edmonton, Alberta , Canada
| | - Katie Murray
- Neuroscience and Mental Health Institute and Faculty of Rehabilitation Medicine, University of Alberta , Edmonton, Alberta , Canada
| | - Shihao Lin
- Neuroscience and Mental Health Institute and Faculty of Rehabilitation Medicine, University of Alberta , Edmonton, Alberta , Canada
| | - Sophie Black
- Neuroscience and Mental Health Institute and Faculty of Rehabilitation Medicine, University of Alberta , Edmonton, Alberta , Canada
| | - Marilee J Stephens
- Neuroscience and Mental Health Institute and Faculty of Rehabilitation Medicine, University of Alberta , Edmonton, Alberta , Canada
| | - Andrew H Ahn
- Teva Pharmaceuticals, Clinical Development, North Wales, Pennsylvania
| | - C J Heckman
- Department of Physiology, Northwestern University, Feinberg School of Medicine , Chicago, Illinois
| | - Keith K Fenrich
- Neuroscience and Mental Health Institute and Faculty of Rehabilitation Medicine, University of Alberta , Edmonton, Alberta , Canada
| | - Karim Fouad
- Neuroscience and Mental Health Institute and Faculty of Rehabilitation Medicine, University of Alberta , Edmonton, Alberta , Canada
| | - David J Bennett
- Neuroscience and Mental Health Institute and Faculty of Rehabilitation Medicine, University of Alberta , Edmonton, Alberta , Canada
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2
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Zynda ER, Grimm MJ, Yuan M, Zhong L, Mace TA, Capitano M, Ostberg JR, Lee KP, Pralle A, Repasky EA. A role for the thermal environment in defining co-stimulation requirements for CD4(+) T cell activation. Cell Cycle 2016; 14:2340-54. [PMID: 26131730 DOI: 10.1080/15384101.2015.1049782] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Maintenance of normal core body temperature is vigorously defended by long conserved, neurovascular homeostatic mechanisms that assist in heat dissipation during prolonged, heat generating exercise or exposure to warm environments. Moreover, during febrile episodes, body temperature can be significantly elevated for at least several hours at a time. Thus, as blood cells circulate throughout the body, physiologically relevant variations in surrounding tissue temperature can occur; moreover, shifts in core temperature occur during daily circadian cycles. This study has addressed the fundamental question of whether the threshold of stimulation needed to activate lymphocytes is influenced by temperature increases associated with physiologically relevant increases in temperature. We report that the need for co-stimulation of CD4+ T cells via CD28 ligation for the production of IL-2 is significantly reduced when cells are exposed to fever-range temperature. Moreover, even in the presence of sufficient CD28 ligation, provision of extra heat further increases IL-2 production. Additional in vivo and in vitro data (using both thermal and chemical modulation of membrane fluidity) support the hypothesis that the mechanism by which temperature modulates co-stimulation is linked to increases in membrane fluidity and membrane macromolecular clustering in the plasma membrane. Thermally-regulated changes in plasma membrane organization in response to physiological increases in temperature may assist in the geographical control of lymphocyte activation, i.e., stimulating activation in lymph nodes rather than in cooler surface regions, and further, may temporarily and reversibly enable CD4+ T cells to become more quickly and easily activated during times of infection during fever.
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Key Words
- APC, antigen-presenting cell
- CD28, cluster of differentiation 28
- CD3, cluster of differentiation 3
- CD4, cluster of differentiation 4
- CD8, cluster of differentiation 8
- CTLA-4, cytotoxic T-lymphocyte-associated protein 4
- CTxB, cholera toxin B subunit
- Ct, cycle threshold
- ELISA, enzyme-linked immunosorbant assay
- EtOH, ethanol
- FITC, fluoroisothiocyanate
- GM1, monosialotetrahexosylganglioside
- IDEAS, imagestream data exploration and analysis software
- IL-2, interleukin 2
- LA, latrunculin A
- MβCD, methyl-β-cyclodextrin
- PD-1, Programmed cell death-1
- PMA, phorbol 12-myristate 13-acetate
- T cell activation
- T cell co-stimulation
- TCR, T cell receptor
- TDI, time delay integration
- TMA-DPH, trimethylammonium diphenylhexatriene
- WBH, whole body hyperthermia.
- fever
- hyperthermia
- immune response
- membrane fluidity
- pMHC, peptide-major histocompatibility complexes
- qRT-PCR, quantitative reverse transcription polymerase chain reaction
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Affiliation(s)
- Evan R Zynda
- a Department of Cell Stress Biology ; Roswell Park Cancer Institute ; Buffalo , NY USA
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3
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Nakase M, Nakase Y, Chardwiriyapreecha S, Kakinuma Y, Matsumoto T, Takegawa K. Intracellular trafficking and ubiquitination of the Schizosaccharomyces pombe amino acid permease Aat1p. Microbiology (Reading) 2012; 158:659-673. [DOI: 10.1099/mic.0.053389-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Mai Nakase
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
| | - Yukiko Nakase
- Department of Biostudies, Kyoto University, Kyoto 6060-8501, Japan
| | - Soracom Chardwiriyapreecha
- Department of Applied Bioresource Science, Faculty of Agriculture, Ehime University, Ehime 790-8566, Japan
| | - Yoshimi Kakinuma
- Department of Applied Bioresource Science, Faculty of Agriculture, Ehime University, Ehime 790-8566, Japan
| | | | - Kaoru Takegawa
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
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4
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Nakase M, Tani M, Morita T, Kitamoto HK, Kashiwazaki J, Nakamura T, Hosomi A, Tanaka N, Takegawa K. Mannosylinositol phosphorylceramide is a major sphingolipid component and is required for proper localization of plasma-membrane proteins in Schizosaccharomyces pombe. J Cell Sci 2010; 123:1578-87. [PMID: 20388730 DOI: 10.1242/jcs.059139] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In Saccharomyces cerevisiae, three classes of sphingolipids contain myo-inositol--inositol phosphorylceramide (IPC), mannosylinositol phosphorylceramide (MIPC) and mannosyldiinositol phosphorylceramide [M(IP)(2)C]. No fission yeast equivalent of Ipt1p, the inositolphosphotransferase that synthesizes M(IP)(2)C from MIPC, has been found in the Schizosaccharomyces pombe genome. Analysis of the sphingolipid composition of wild-type cells confirmed that MIPC is the terminal and most abundant complex sphingolipid in S. pombe. Three proteins (Sur1p, Csg2p and Csh1p) have been shown to be involved in the synthesis of MIPC from IPC in S. cerevisiae. The S. pombe genome has three genes (SPAC2F3.01, SPCC4F11.04c and SPAC17G8.11c) that are homologues of SUR1, termed imt1(+), imt2(+) and imt3(+), respectively. To determine whether these genes function in MIPC synthesis in S. pombe, single and multiple gene disruptants were constructed. Single imt disruptants were found to be viable. MIPC was not detected and IPC levels were increased in the triple disruptant, indicating that the three SUR1 homologues are involved in the synthesis of MIPC. GFP-tagged Imt1p, Imt2p and Imt3p localized to Golgi apparatus membranes. The MIPC-deficient mutant exhibited pleiotropic phenotypes, including defects in cellular and vacuolar morphology, and in localization of ergosterols. MIPC seemed to be required for endocytosis of a plasma-membrane-localized amino acid transporter, because sorting of the transporter from the plasma membrane to the vacuole was severely impaired in the MIPC-deficient mutant grown under nitrogen-limiting conditions. These results suggest that MIPC has multiple functions not only in the maintenance of cell and vacuole morphology but also in vesicular trafficking in fission yeast.
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Affiliation(s)
- Mai Nakase
- Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan
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5
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Zhang N, Shaw ARE, Li N, Chen R, Mak A, Hu X, Young N, Wishart D, Li L. Liquid chromatography electrospray ionization and matrix-assisted laser desorption ionization tandem mass spectrometry for the analysis of lipid raft proteome of monocytes. Anal Chim Acta 2008; 627:82-90. [PMID: 18790130 DOI: 10.1016/j.aca.2008.05.058] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 05/22/2008] [Accepted: 05/24/2008] [Indexed: 10/22/2022]
Abstract
Lipid rafts are dynamic assemblies of cholesterol and glycolipid that form detergent-insoluble microdomains within membrane lipid bilayers. Because rafts can be separated by flotation on sucrose gradients, interrogation by mass spectrometry (MS) provides a valuable new insight into lipid raft function. Here we combine liquid chromatography (LC) electrospray ionization (ESI) and matrix-assisted laser desorption ionization (MALDI) MS/MS to corroborate and extend our previous description of lipid raft proteomes derived from the monocytic cell line THP-1. Interestingly, LC-ESI and MALDI MS/MS identify largely non-overlapping, and therefore, potentially complementary protein populations. Using the combined approach, we detected 277 proteins compared to 52 proteins obtained with the original gel-based MALDI MS. We confirmed the presence of 47 of the original 52 proteins demonstrating the consistency of the lipid raft preparations. We demonstrated by immunoblotting that Rac 1 and Rac 2, two of the 52 proteins we failed to confirm, were indeed absent from the lipid raft fractions. The majority of new proteins were cytoskeletal proteins and their regulators, proteins implicated in membrane fusion and vesicular trafficking or signaling molecules. Our results therefore, confirm and extend previous evidence indicating lipid rafts of monocytic cells are specialized for cytoskeletal assembly and vesicle trafficking. Of particular interest, we detected SNAP-23, basigin, Glut-4 and pantophysin in lipid rafts. Since these proteins are implicated in both vesicular trafficking and gamete fusion, lipid rafts may play a common role in these processes. It is evident that the combination of LC-ESI and LC-MALDI MS/MS increases the proteome coverage which allows better understanding of the lipid raft function.
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Affiliation(s)
- Nan Zhang
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
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6
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Rose JJ, Foley JF, Yi L, Herren G, Venkatesan S. Cholesterol is obligatory for polarization and chemotaxis but not for endocytosis and associated signaling from chemoattractant receptors in human neutrophils. J Biomed Sci 2008; 15:441-61. [DOI: 10.1007/s11373-008-9239-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Accepted: 02/13/2008] [Indexed: 10/22/2022] Open
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7
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Drbal K, Moertelmaier M, Holzhauser C, Muhammad A, Fuertbauer E, Howorka S, Hinterberger M, Stockinger H, Schütz GJ. Single-molecule microscopy reveals heterogeneous dynamics of lipid raft components upon TCR engagement. Int Immunol 2007; 19:675-84. [PMID: 17446208 DOI: 10.1093/intimm/dxm032] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The existence of lipid rafts and their importance for immunoreceptor signaling is highly debated. By non-invasive single molecule imaging, we analyzed the dynamics of the T-cell antigen receptor (TCR), the lipid raft-associated glycosylphosphatidylinositol (GPI) proteins CD48 and CD59 and the major leukocyte phosphatase CD45 in living naive T lymphocytes. TCR triggering induced the immobilization of CD45 and CD48 at different positions within the T-cell interface. The second GPI protein, CD59, did not co-immobilize indicating lipid raft heterogeneity in living T lymphocytes. A novel biochemical approach confirmed that lipid raft components are not associated in the plasma membrane of resting cells, and variably associate with specific receptors to distinct lipid rafts upon activation.
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Affiliation(s)
- Karel Drbal
- Competence Centre for Biomolecular Therapeutics Research Vienna, A-1090, Vienna
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8
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Eren E, Yates J, Cwynarski K, Preston S, Dong R, Germain C, Lechler R, Huby R, Ritter M, Lombardi G. Location of major histocompatibility complex class II molecules in rafts on dendritic cells enhances the efficiency of T-cell activation and proliferation. Scand J Immunol 2006; 63:7-16. [PMID: 16398696 DOI: 10.1111/j.1365-3083.2006.01700.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The existence of major histocompatibility complex (MHC) class II molecules in lipid rafts has been described in dendritic cells (DC); however, the importance of rafts in T-cell activation has not been clarified. In this study, the distribution of the lipid raft components (CD59 and GM1 ganglioside) in human monocyte-derived DC was investigated. DC had an even distribution of these components at the cell surface. In addition, raft-associated GM1 ganglioside colocalized with cross-linked MHC class II. This implies coaggregation of raft components with these MHC molecules, which may be important in the interaction between T cells and antigen-presenting cells. In studies carried out to investigate the effect of the DC : T-cell interaction on raft distribution, we found a clustering of the lipid raft component CD59 on DC at the synaptic interface, with associated activation of the interacting T cell. In an antigen-specific response between DC and CD4+ T-cell clones, disruption of lipid rafts resulted in inhibition of both CD59 clustering and T-cell activation. This was most pronounced when limiting amounts of cognate peptide were used. Together, these data demonstrate the association of MHC class II with lipid rafts during DC : T-cell interaction and suggest an important role for DC lipid rafts in T-cell activation.
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Affiliation(s)
- E Eren
- Department of Immunology, Imperial College London, Hammersmith Campus, London, UK
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9
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Rouquette-Jazdanian AK, Foussat A, Lamy L, Pelassy C, Lagadec P, Breittmayer JP, Aussel C. Cholera toxin B-subunit prevents activation and proliferation of human CD4+ T cells by activation of a neutral sphingomyelinase in lipid rafts. THE JOURNAL OF IMMUNOLOGY 2005; 175:5637-48. [PMID: 16237053 DOI: 10.4049/jimmunol.175.9.5637] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The inhibition of human CD4+ T lymphocyte activation and proliferation by cholera toxin B-subunit (CTB) is a well-established phenomenon; nevertheless, the exact mechanism remained unclear. In the present study, we propose an explanation for the rCTB-induced inhibition of CD4+ T lymphocytes. rCTB specifically binds to GM1, a raft marker, and strongly modifies the lipid composition of rafts. First, rCTB inhibits sphingomyelin synthesis; second, it enhances phosphatidylcholine synthesis; and third, it activates a raft-resident neutral sphingomyelinase resembling to neutral sphingomyelinase type 1, thus generating a transient ceramide production. We demonstrated that these ceramides inhibit protein kinase Calpha phosphorylation and its translocation into the modified lipid rafts. Furthermore, we show that rCTB-induced ceramide production activate NF-kappaB. Combined all together: raft modification in terms of lipids, ceramide production, protein kinase Calpha inhibition, and NF-kappaB activation lead to CD4+ T cell inhibition.
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Affiliation(s)
- Alexandre K Rouquette-Jazdanian
- Institut National de la Santé et de la Recherche Médicale (INSERM) Unit 576, IFR 50, Hôpital de l'Archet I, Nice Cedex 3, France
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10
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Nguyen DH, Giri B, Collins G, Taub DD. Dynamic reorganization of chemokine receptors, cholesterol, lipid rafts, and adhesion molecules to sites of CD4 engagement. Exp Cell Res 2004; 304:559-69. [PMID: 15748900 DOI: 10.1016/j.yexcr.2004.11.022] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2004] [Revised: 11/16/2004] [Accepted: 11/18/2004] [Indexed: 11/18/2022]
Abstract
T cell polarization and redistribution of cellular components are critical to processes such as activation, migration, and potentially HIV infection. Here, we investigate the effects of CD4 engagement on the redistribution and localization of chemokine receptors, CXCR4 and CCR5, adhesion molecules, and lipid raft components including cholesterol, GM1, and glycosyl-phosphatidylinositol (GPI)-anchored proteins. We demonstrate that anti-CD4-coated beads (alpha CD4-B) rapidly induce co-capping of chemokine receptors as well as GPI-anchored proteins and adhesion molecules with membrane cholesterol and lipid rafts on human T cell lines and primary T cells to the area of bead-cell contact. This process was dependent on the presence of cellular cholesterol, cytoskeletal reorganization, and lck signaling. Lck-deficient JCaM 1.6 cells failed to cap CXCR4 or lipid rafts to alpha CD4-B. Biochemical analysis reveals that CXCR4 and LFA-1 are recruited to lipid rafts upon CD4 but not CD45 engagement. Furthermore, we also demonstrate T cell capping of both lipid rafts and chemokine receptors at sites of contact with HIV-infected cells, despite the binding of an HIV inhibitory mAb to CXCR4. We conclude that cell surface rearrangements in response to CD4 engagement may serve as a means to enhance cell-to-cell signaling at the immunological synapse and modulate chemokine responsiveness, as well as facilitate HIV entry and expansion by synaptic transmission.
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Affiliation(s)
- Dzung H Nguyen
- Laboratory of Immunology, National Institute on Aging, Intramural Research Program, NIH, DHHS, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA
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11
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Fan YY, Ly LH, Barhoumi R, McMurray DN, Chapkin RS. Dietary Docosahexaenoic Acid Suppresses T Cell Protein Kinase Cθ Lipid Raft Recruitment and IL-2 Production. THE JOURNAL OF IMMUNOLOGY 2004; 173:6151-60. [PMID: 15528352 DOI: 10.4049/jimmunol.173.10.6151] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
To date, the proximal molecular targets through which dietary n-3 polyunsaturated fatty acids (PUFA) suppress the inflammatory process have not been elucidated. Because cholesterol and sphingolipid-enriched rafts have been proposed as platforms for compartmentalizing dynamically regulated signaling assemblies at the plasma membrane, we determined the in vivo effects of fish oil and highly purified docosahexaenoic acid (DHA; 22:6n-3) on T cell microdomain lipid composition and the membrane subdomain distribution of signal-transducing molecules (protein kinase C (PKC)theta;, linker for activation of T cells, and Fas/CD95), before and after stimulation. Mice were fed diets containing 5 g/100 g corn oil (control), 4 g/100 g fish oil (contains a mixture of n-3 PUFA) plus 1 g/100 g corn oil, or 4 g/100 g corn oil plus 1 g/100 g DHA ethyl ester for 14 days. Dietary n-3 PUFA were incorporated into splenic T cell lipid raft and soluble membrane phospholipids, resulting in a 30% reduction in raft sphingomyelin content. In addition, polyclonal activation-induced colocalization of PKCtheta; with lipid rafts was reduced by n-3 PUFA feeding. With respect to PKCtheta; effector pathway signaling, both AP-1 and NF-kappaB activation, IL-2 secretion, and lymphoproliferation were inhibited by fish oil feeding. Similar results were obtained when purified DHA was fed. These data demonstrate for the first time that dietary DHA alters T cell membrane microdomain composition and suppresses the PKCtheta; signaling axis.
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Affiliation(s)
- Yang-Yi Fan
- Molecular and Cell Biology Section, Faculty of Nutrition, Texas A&M University Health Science Center, College Station, TX 77843-2471, USA
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12
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Abstract
Ejaculated mammalian sperm must complete a final maturation, termed capacitation, before they can undergo acrosomal exocytosis and fertilize an egg. In human sperm, loss of sperm sterol is an obligatory, early event in capacitation. How sterol loss leads to acrosomal responsiveness is unknown. These experiments tested the hypothesis that loss of sperm sterol affects the organization of cold detergent-resistant membrane microdomains (lipid "rafts"). The GPI-linked protein CD59, the ganglioside GM1, and the protein flotillin-2 were used as markers for lipid rafts. In uncapacitated sperm, 51% of the CD59, 41% of the GM1, and 90% of the flotillin-2 were found in the raft fraction. During capacitation, sperm lost 67% of their 3beta-hydroxysterols, and the percentages of CD59 and GM1 in the raft fraction decreased to 34% and 31%, respectively. The distribution of flotillin-2 did not change. Preventing a net loss of sperm sterol prevented the loss of CD59 and GM1 from the raft fraction. Fluorescence microscopy showed CD59 and GM1 to be distributed over the entire sperm surface. Flotillin-2 was located mainly in the posterior head and midpiece. Patching using bivalent antibodies indicated that little of the GM1 and CD59 was stably associated in the same membrane rafts. Likewise, GM1 and flotillin-2 were not associated in the same membrane rafts. In summary, lipid rafts of heterogeneous composition were identified in human sperm and the two raft components, GM1 and CD59, showed a partial sterol loss-dependent shift to the nonraft domain during capacitation.
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Affiliation(s)
- Nicholas L Cross
- Department of Physiological Sciences, Oklahoma State University, Stillwater, Oklahoma 74078, USA.
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Taner SB, Onfelt B, Pirinen NJ, McCann FE, Magee AI, Davis DM. Control of Immune Responses by Trafficking Cell Surface Proteins, Vesicles and Lipid Rafts to and from the Immunological Synapse. Traffic 2004; 5:651-61. [PMID: 15296490 DOI: 10.1111/j.1600-0854.2004.00214.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Supramolecular clusters at the immunological synapse provide a mechanism for structuring complex communication networks between cells of the immune system. Regulating intra- and intercellular trafficking of proteins and lipids to and from the immunological synapse provides an additional level of complexity in determining the functional outcome of immune cell interactions. An emergent principle is that molecules requiring tightly regulated cell surface expression, e.g. negative regulators of cell activation or molecules promoting cytotoxicity, are trafficked to the immunological synapse from intracellular secretory as required lysosomes. Many molecules required for the early stages of the intercellular communication are already present at the cell surface, sometimes in lipid rafts, and are rapidly translocated laterally to the intercellular contact. Our understanding of these events critically depends on utilizing appropriate technologies for probing supramolecular recognition in live cells. Thus, we also present here a critical discussion of the technologies used to study lipid rafts and, more broadly, a map of the spatial and temporal dimensions covered by current live cell physical techniques, highlighting where advances are needed to exceed current spatial and temporal boundaries.
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Affiliation(s)
- Sabrina B Taner
- Department of Biological Sciences, Imperial College London, SW7 2AZ, UK
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14
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Gri G, Molon B, Manes S, Pozzan T, Viola A. The inner side of T cell lipid rafts. Immunol Lett 2004; 94:247-52. [PMID: 15275973 DOI: 10.1016/j.imlet.2004.05.012] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2004] [Revised: 05/17/2004] [Accepted: 05/17/2004] [Indexed: 12/13/2022]
Abstract
A key question in understanding the functional role of lipid rafts is whether lipid microdomains at the plasma membrane outer leaflet are coupled to lipid microdomains at the inner leaflet. By using a cyan-fluorescent protein (CFP) targeted to inner plasma membrane rafts of Jurkat T cells, we found that raft domains at the outer and inner leaflets are physically coupled and that this coupling requires cholesterol. Interestingly, TCR/CD3 cross-linking induces co-capping of the raft bilayer independently of cholesterol or signaling events, indicating that cholesterol-extracting drugs are unable to destroy TCR-lipid rafts interaction.
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Affiliation(s)
- Giorgia Gri
- Department of Biomedical Sciences, Venetian Institute of Molecular Medicine, University of Padua, 35129 Padua, Italy.
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15
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Rose JJ, Foley JF, Murphy PM, Venkatesan S. On the mechanism and significance of ligand-induced internalization of human neutrophil chemokine receptors CXCR1 and CXCR2. J Biol Chem 2004; 279:24372-86. [PMID: 15028716 DOI: 10.1074/jbc.m401364200] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
It is well established that leukocyte chemotactic receptors, a subset of G protein-coupled receptors, undergo endocytosis after stimulation by ligand. However, the significance of this phenomenon to cell motility and other important leukocyte functions induced by chemoattractants has not been clearly defined. Here we show that in primary human neutrophils, the threshold levels of agonist required for endocytosis of the chemotactic receptors CXCR1 and CXCR2 were approximately 10-fold or higher than those needed for maximal chemotactic and calcium flux responses. Moreover, when stimulated by agonists at concentrations that are high enough for chemotaxis but too low for receptor endocytosis, neutrophil CXCR1 and CXCR2 could be reactivated in response to repeated application of the same agonist. Both receptors were excluded from Triton X-100-insoluble lipid rafts, and at high agonist concentrations were rapidly endocytosed by a clathrin/rab5/dynamin-dependent pathway. These data support the conclusion that neutrophil migration in response to CXCR1 or CXCR2 agonists is not dependent on endocytosis of CXCR1 or CXCR2. Rather than being integral to the process of cell migration, receptor endocytosis may be a terminal stop signal when cells reach the focus of inflammation where the chemoattractant concentrations are the highest.
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Affiliation(s)
- Jeremy J Rose
- Laboratory of Molecular Microbiology, NIAID, National Institutes of Health, Bethesda, Maryland 20892, USA
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16
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Staffler G, Szekeres A, Schütz GJ, Säemann MD, Prager E, Zeyda M, Drbal K, Zlabinger GJ, Stulnig TM, Stockinger H. Selective inhibition of T cell activation via CD147 through novel modulation of lipid rafts. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:1707-14. [PMID: 12902469 DOI: 10.4049/jimmunol.171.4.1707] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The plasma membrane is compartmentalized into microdomains and the association/dissociation of receptors and signaling molecules with/from these membrane domains is a major principle for regulation of signal transduction. By following the reorganization of microdomains on living cells and performing biochemical studies, we show that Ab targeting of the T cell activation-associated Ag CD147 prevents TCR stimulation-dependent reorganization and clustering of microdomains. Triggering CD147 induces a displacement of the GPI-anchored coreceptors CD48 and CD59 from microdomains in human T lymphocytes. This perturbation of microdomains is accompanied by a selective inhibition of TCR-mediated T cell proliferation. The CD147-inhibited cells secret normal levels of IL-2 but acquire reduced amounts of the IL-2 receptor alpha-chain CD25. These results indicate that negative regulating signals can modulate microdomains and suggest a general mechanism for inhibition of receptor signaling.
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MESH Headings
- Antibodies, Monoclonal/pharmacology
- Antigens, CD
- Antigens, Neoplasm
- Antigens, Surface
- Avian Proteins
- Basigin
- Blood Proteins
- CD28 Antigens/immunology
- CD28 Antigens/physiology
- Cell Division/immunology
- Cell Separation
- Cells, Cultured
- Cytokines/genetics
- Cytokines/metabolism
- Down-Regulation/immunology
- Humans
- Immunologic Capping/immunology
- Interleukin-2/antagonists & inhibitors
- Interleukin-2/metabolism
- Isoantigens/physiology
- Lymphocyte Activation/immunology
- Lymphocyte Culture Test, Mixed
- Membrane Glycoproteins/immunology
- Membrane Glycoproteins/physiology
- Membrane Microdomains/immunology
- Membrane Microdomains/metabolism
- Membrane Microdomains/physiology
- Muromonab-CD3/pharmacology
- Phosphorylation
- Phosphotyrosine/metabolism
- Receptor-CD3 Complex, Antigen, T-Cell/antagonists & inhibitors
- Receptor-CD3 Complex, Antigen, T-Cell/immunology
- Receptor-CD3 Complex, Antigen, T-Cell/physiology
- Receptors, Cytokine/genetics
- Receptors, Cytokine/metabolism
- Signal Transduction/immunology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Transcription, Genetic/immunology
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17
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Ong KW, Wilson AD, Hirst TR, Morgan AJ. The B subunit of Escherichia coli heat-labile enterotoxin enhances CD8+ cytotoxic-T-lymphocyte killing of Epstein-Barr virus-infected cell lines. J Virol 2003; 77:4298-305. [PMID: 12634387 PMCID: PMC150673 DOI: 10.1128/jvi.77.7.4298-4305.2003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Epstein-Barr virus (EBV) is associated with a number of important human cancers, including nasopharyngeal carcinoma, gastric carcinoma, and Hodgkin's lymphoma. These tumors express a viral nuclear antigen, EBV nuclear antigen 1 (EBNA1), which cannot be presented to T cells in a major histocompatibility complex class I context, and the viral latent membrane proteins (LMPs). Although the LMPs are expressed in these tumors, no effective immune response is made. We report here that exposure to the cholera-like enterotoxin B subunit (EtxB) in EBV-infected lymphoblastoid cell lines (LCLs) enhances their susceptibility to killing by LMP-specific CD8(+) cytotoxic T lymphocytes (CTLs) in a HLA class I-restricted manner. CTL killing of LCLs is dramatically increased through both transporter-associated protein-dependent and -independent epitopes after EtxB treatment. The use of mutant B subunits revealed that the enhanced susceptibility of LCLs to CTL killing is dependent on the B subunit's interaction with GM(1) but not its signaling properties. These important findings could underpin the development of novel approaches to treating EBV-associated malignancies and may offer a general approach to increasing the presentation of other tumor and viral antigens.
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Affiliation(s)
- Kong-Wee Ong
- Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, United Kingdom
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18
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Kovacs B, Maus MV, Riley JL, Derimanov GS, Koretzky GA, June CH, Finkel TH. Human CD8+ T cells do not require the polarization of lipid rafts for activation and proliferation. Proc Natl Acad Sci U S A 2002; 99:15006-11. [PMID: 12419850 PMCID: PMC137535 DOI: 10.1073/pnas.232058599] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lipid rafts are important signaling platforms in T cells. Little is known about their properties in human CD8(+) T cells. We studied polarization of lipid rafts by digital immunofluorescence microscopy in primary human T cells, using beads coated with anti-CD3 and anti-CD28 mAbs (CD3/28 beads). Unlike CD4(+) T cells, CD8(+) T cells did not polarize lipid rafts when stimulated with CD3/28 beads, when the anti-CD28 antibody was substituted with B7.2Ig, or if an anti-CD8 antibody was added to the CD3/28 beads. This phenomenon was also observed in human antigen-specific CD8(+) T cells. On stimulation with CD3/28 beads, the T cell antigen receptor clustered at the cell/bead contact area in both CD4(+) and CD8(+) T cells. Examination of lipid rafts isolated by sucrose density gradient centrifugation revealed the constitutive expression of p(56)Lck in the raft fractions of unstimulated CD8(+) T cells, whereas p(56)Lck was recruited to the raft fraction of CD4(+) T cells only after stimulation with CD3/28 beads. Stimulation with CD3/28 beads induced marked calcium flux, recruitment of PKC-theta and F-actin to the cell/bead contact site, and similar proliferation patterns in CD4(+) and CD8(+) T cells. Thus, polarization of lipid rafts is not essential for early signal transduction events or proliferation of human CD8(+) lymphocytes. It is possible that the lower stringency of CD8(+) T cell activation obviates a requirement for raft polarization.
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Affiliation(s)
- Birgit Kovacs
- Division of Rheumatology, Department of Pediatrics, Children's Hospital of Philadelphia, PA 19104, USA
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19
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Casanova JE. Epithelial cell cytoskeleton and intracellular trafficking V. Confluence of membrane trafficking and motility in epithelial cell models. Am J Physiol Gastrointest Liver Physiol 2002; 283:G1015-9. [PMID: 12381513 DOI: 10.1152/ajpgi.00255.2002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Migration of epithelial cells occurs in a variety of important biological processes including tissue morphogenesis, wound healing, and the metastasis of epithelial tumors. In some instances, the cells remain attached to each other and migrate together as a sheet, maintaining epithelial integrity. In others (e.g., metastasis), junctional complexes are disrupted and cells migrate individually. In both cases, motility involves the extension of membranous protrusions (filopodia and lamellipodia) in the direction of movement and the transient assembly and disassembly of integrin-mediated adhesions with the extracellular matrix. The driving force for these events is provided by regulated changes in the organization of the actin cytoskeleton, which are thought to be coordinated with alterations in intracellular membrane traffic. In this themes article, I review current hypotheses about how these processes are integrated and attempt to identify fruitful areas for future research.
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Affiliation(s)
- James E Casanova
- Department of Cell Biology, University of Virginia Health System, Charlottesville, Virginia 22908-0732, USA.
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20
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Wonerow P, Obergfell A, Wilde JI, Bobe R, Asazuma N, Brdicka T, Leo A, Schraven B, Horejsí V, Shattil SJ, Watson SP. Differential role of glycolipid-enriched membrane domains in glycoprotein VI- and integrin-mediated phospholipase Cgamma2 regulation in platelets. Biochem J 2002; 364:755-65. [PMID: 12049640 PMCID: PMC1222625 DOI: 10.1042/bj20020128] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The platelet collagen receptor glycoprotein VI (GPVI) and the fibrinogen receptor integrin alphaIIbbeta3 trigger intracellular signalling cascades involving the tyrosine kinase Syk, the adapter SLP-76 and phospholipase Cgamma2 (PLCgamma2). Similar pathways are activated downstream of immune receptors in lymphocytes, where they have been localized in part to glycolipid-enriched membrane domains (GEMs). Here we provide several lines of evidence that GPVI-mediated tyrosine phosphorylation of PLCgamma2 in platelets is dependent on GEM-organized signalling and utilizes the GEM resident adapter protein LAT (linker for activation of T cells). In sharp contrast, although fibrinogen binding to platelets stimulates alphaIIbbeta3-dependent activation of Syk and tyrosine phosphorylation of SLP-76 and PLCgamma2, it does not utilize GEMs to promote these responses or to support platelet aggregation. These results establish that GPVI and alphaIIbbeta3 trigger distinct patterns of receptor signalling in platelets, leading to tyrosine phosphorylation of PLCgamma2, and they highlight the role of GEMs in compartmentalizing signalling reactions involved in haemostasis.
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Affiliation(s)
- Peter Wonerow
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
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21
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Garofalo T, Lenti L, Longo A, Misasi R, Mattei V, Pontieri GM, Pavan A, Sorice M. Association of GM3 with Zap-70 induced by T cell activation in plasma membrane microdomains: GM3 as a marker of microdomains in human lymphocytes. J Biol Chem 2002; 277:11233-8. [PMID: 11781312 DOI: 10.1074/jbc.m109601200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Recent evidence demonstrated that T cell activation leads to the redistribution of membrane and intracellular kinase-rich raft microdomains at the site of TCR engagement. In this investigation we demonstrated by high performance thin layer chromatography, gas chromatographic, and mass spectrometric analyses that GM3 is the main ganglioside constituent of these microdomains in human lymphocytes. Then we analyzed GM3 distribution and its interaction with the phosphorylation protein Zap-70. Human T lymphocytes were stimulated with anti-CD3 and anti-CD28. Immunofluorescence microscopy analysis revealed a clustered GM3 distribution over the cell surface and an intracellular localization resembling specific cytoplasmic compartment(s). Scanning confocal microscopy showed that T cell activation induced a significant association between GM3 and Zap-70, as revealed by nearly complete colocalization areas; very few colocalization areas were detected in unstimulated cells. Coimmunoprecipitation experiments revealed that GM3 was immunoprecipitated by anti-Zap-70 only after co-stimulation through CD3 and CD28 as detected by both thin layer chromatography and immunoblotting. Therefore, T cell activation does not promote a redistribution of glycosphingolipid-enriched microdomains but induces Zap-70 translocation in selective membrane domains in which Zap-70 may interact with GM3. These findings suggest that GM3 is a component of a multimolecular signaling complex involved in T cell activation.
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Affiliation(s)
- Tina Garofalo
- Dipartimento Medicina Sperimentale e Patologia, Università La Sapienza Roma, Italy
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22
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Mitchell JS, Kanca O, McIntyre BW. Lipid microdomain clustering induces a redistribution of antigen recognition and adhesion molecules on human T lymphocytes. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:2737-44. [PMID: 11884440 DOI: 10.4049/jimmunol.168.6.2737] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The study of lipid microdomains in the plasma membrane is a topic of recent interest in leukocyte biology. Many T cell activation and signaling molecules are found to be associated with lipid microdomains and have been implicated in normal T cell function. It has been proposed that lipid microdomains with their associated molecules move by lateral diffusion to areas of cellular interactions to initiate signaling pathways. Using sucrose density gradients we have found that human T cell beta(1) integrins are not normally associated with lipid microdomains. However, cross-linking of GM1 through cholera toxin B-subunit (CTB) causes an enrichment of beta(1) integrins in microdomain fractions, suggesting that cross-linking lipid microdomains causes a reorganization of molecular associations. Fluorescent microscopy was used to examine the localization of various lymphocyte surface molecules before and after lipid microdomain cross-linking. Lymphocytes treated with FITC-CTB reveal an endocytic vesicle that is enriched in TCR and CD59, while beta(1) integrin, CD43, and LFA-3 were not localized in the vesicle. However, when anti-CTB Abs are used to cross-link lipid microdomains, the microdomains are not internalized but are clustered on the cell surface. In this study, CD59, CD43, and beta(1) integrin are all seen to colocalize in a new lipid microdomain from which LFA-3 remains excluded and the TCR is now dissociated. These findings show that cross-linking lipid microdomains can cause a dynamic rearrangement of the normal order of T lymphocyte microdomains into an organization where novel associations are created and signaling pathways may be initiated.
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Affiliation(s)
- Jason S Mitchell
- Department of Immunology, University of Texas, M. D. Anderson Cancer Center, Houston, TX 77030, USA
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23
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Montoya MC, Sancho D, Bonello G, Collette Y, Langlet C, He HT, Aparicio P, Alcover A, Olive D, Sánchez-Madrid F. Role of ICAM-3 in the initial interaction of T lymphocytes and APCs. Nat Immunol 2002; 3:159-68. [PMID: 11812993 DOI: 10.1038/ni753] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Antigen-independent adhesive interactions between T lymphocytes and antigen-presenting cells (APCs) are essential for scanning for specific antigens on the APC surface and for initiating the immune response. Here we show, through time-lapse imaging of live cells, that the intercellular adhesion molecule 3 (ICAM-3, also known as CD50) is clustered specifically at the region of the T lymphocyte surface that initiates contact with APCs. We describe the role of ICAM-3 in T cell-APC conjugate formation before antigen recognition, in early intracellular signaling and in cytoskeletal rearrangement. Our data indicate that ICAM-3 is important in the initial scanning of the APC surface by T cells and, therefore, in generating the immune response.
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Affiliation(s)
- María C Montoya
- Servicio de Inmunología, Hospital de la Princesa, C/ Diego de León 62, Universidad Autónoma de Madrid, 28006 Madrid, Spain
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24
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Millán J, Montoya MC, Sancho D, Sánchez-Madrid F, Alonso MA. Lipid rafts mediate biosynthetic transport to the T lymphocyte uropod subdomain and are necessary for uropod integrity and function. Blood 2002; 99:978-84. [PMID: 11807002 DOI: 10.1182/blood.v99.3.978] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Polarized migrating T cells possess 2 poles, the uropod protrusion at the rear and the leading edge at the front, with specific protein composition and function. The influenza virus hemagglutinin (HA) is a prototypical molecule that uses lipid rafts for biosynthetic transport to the apical surface in polarized epithelial Madin-Darby canine kidney (MDCK) cells. In this study, HA was used as a tool to investigate the role of lipid rafts in vectorial protein traffic in polarized T lymphocytes. Results show that newly synthesized HA becomes selectively targeted to the uropod subdomain in polarized T lymphoblasts. HA incorporates into rafts soon after biosynthesis, suggesting that delivery of HA to the uropod occurs through a pathway of transport reminiscent of that used for its specific targeting to the apical surface. HA and the adhesion molecules, intercellular adhesion molecule 3 (ICAM-3), CD44, and CD43, 3 endogenous uropod markers, were detected in surface rafts of T lymphoblasts. Cholesterol, a major component of lipid rafts, was predominantly located in the uropod. Disruption of lipid raft integrity by cholesterol sequestration produced unclustering of ICAM-3 and the loss of uropodia and severely impaired processes that require a polarized phenotype such as intercellular aggregation and cell migration. Collectively, these results indicate that lipid rafts constitute a route for selective targeting of proteins to the uropod and that the rafts are essential for the generation, maintenance, and functionality of T-cell anteroposterior polarity.
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Affiliation(s)
- Jaime Millán
- Severo Ochoa Center for Molecular Biology, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, Cantoblanco 280-49 Madrid, Spain
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25
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Abstract
Efficient unidirectional killing by cytotoxic T lymphocytes (CTL) requires translocation of the microtubule organizing center (MTOC) to the target cell contact site. Here we utilize modulated polarization microscopy and computerized 3D reconstruction of tubulin and LFA-1 immunofluorescence images to investigate how this is accomplished. The results show that the MTOC is drawn vectorially to the contact site by a microtubule sliding mechanism. Once the MTOC arrives at the contact site, it oscillates laterally. Microtubules loop through and anchor to a ring-shaped zone (pSMAC) defined by the dense clustering of LFA-1 at the target contact site. Microtubules that run straight between the MTOC and pSMAC and then turn sharply may indicate the action of a microtubule motor such as dynein.
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Affiliation(s)
- Jeffrey R Kuhn
- Division of Molecular Cell and Developmental Biology, 141 Patterson Labs, University of Texas at Austin, Austin, TX 78712, USA
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26
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Alonso MA, Millán J. The role of lipid rafts in signalling and membrane trafficking in T lymphocytes. J Cell Sci 2001; 114:3957-65. [PMID: 11739628 DOI: 10.1242/jcs.114.22.3957] [Citation(s) in RCA: 174] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Combinatorial association of different lipid species generates microheterogeneity in biological membranes. The association of glycosphingolipids with cholesterol forms membrane microdomains – lipid rafts – that are involved in specialised pathways of protein/lipid transport and signalling. Lipid rafts are normally dispersed in cellular membranes and appear to require specialised machinery to reorganise them to operate. Caveolin-1 and MAL are members of two different protein families involved in reorganisation of lipid rafts for signalling and/or intracellular transport in epithelial cells. T cell activation induces a rapid compartmentalisation of signalling machinery into reorganised rafts that are used as platforms for the assembly of the signalling complex. Costimulatory molecules participate in this process by providing signals that mobilise raft lipids and proteins, and remodel the cytoskeleton to the contact site. As in epithelial cells, rafts are used also as vesicular carriers for membrane trafficking in T lymphocytes. Furthermore, there are potential similarities between the specialised protein machinery underlying raft-mediated processes in T lymphocytes and polarised epithelial cells.
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Affiliation(s)
- M A Alonso
- Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid, Consejo Superior de Investigaciones Científicas, Cantoblanco, 28049-Madrid, Spain.
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27
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Dykstra M, Cherukuri A, Pierce SK. Rafts and synapses in the spatial organization of immune cell signaling receptors. J Leukoc Biol 2001. [DOI: 10.1189/jlb.70.5.699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Michelle Dykstra
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Anu Cherukuri
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
| | - Susan K. Pierce
- Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland
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28
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Dietrich C, Volovyk ZN, Levi M, Thompson NL, Jacobson K. Partitioning of Thy-1, GM1, and cross-linked phospholipid analogs into lipid rafts reconstituted in supported model membrane monolayers. Proc Natl Acad Sci U S A 2001; 98:10642-7. [PMID: 11535814 PMCID: PMC58519 DOI: 10.1073/pnas.191168698] [Citation(s) in RCA: 282] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2001] [Indexed: 12/31/2022] Open
Abstract
As shown earlier, raft-like domains resembling those thought to be present in natural cell membranes can be formed in supported planar lipid monolayers. These liquid-ordered domains coexist with a liquid-disordered phase and form in monolayers prepared both from synthetic lipid mixtures and lipid extracts of the brush border membrane of mouse kidney cells. The domains are detergent-resistant and are highly enriched in the glycosphingolipid GM1. In this work, the properties of these raft-like domains are further explored and compared with properties thought to be central to raft function in plasma membranes. First, it is shown that domain formation and disruption critically depends on the cholesterol density and can be controlled reversibly by treating the monolayers with the cholesterol-sequestering reagent methyl-beta-cyclodextrin. Second, the glycosylphosphatidylinositol-anchored cell-surface protein Thy-1 significantly partitions into the raft-like domains. The extent of this partitioning is reduced when the monolayers contain GM1, indicating that different molecules can compete for domain occupation. Third, the partitioning of a saturated phospholipid analog into the raft phase is dramatically increased (15% to 65%) after cross-linking with antibodies, whereas the distribution of a doubly unsaturated phospholipid analog is not significantly affected by cross-linking (approximately 10%). This result demonstrates that cross-linking, a process known to be important for certain cell-signaling processes, can selectively translocate molecules to liquid-ordered domains.
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Affiliation(s)
- C Dietrich
- Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, NC 27599, USA
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