1
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Schulte M, Hensel M. Flow Cytometry-Based Single Cell Analyses of Bacterial Adaptation to Intracellular Environments. Methods Mol Biol 2022; 2427:105-117. [PMID: 35619029 DOI: 10.1007/978-1-0716-1971-1_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Since decades, flow cytometry (FC) is a powerful technique to perform single cell analyses with high accuracy and throughput. Moreover, FC is the method of choice to study bacterial cell heterogeneity and complements single-cell imaging techniques. The complex experimental approaches for FC sample preparation and the subsequent FC adjustment and gating strategy demand careful considerations to be successful when analyzing complex microbial populations, especially when liberated populations of intracellular bacterial pathogens, or bacterial pathogens inside intact host cells are analyzed. Here, we provide a set of experimental protocols for FC sample preparation of (1) in vitro cultured bacterial cells, (2) liberated intracellular bacteria from host cells, or (3) preparation of intact infected phagocytic or epithelial cells commonly used as host cells in infection biology. Since sample preparation, cytometer adjustment, and gating strategy are essential for experimental success, we aim to provide our expertise to support application of FC by other researchers.
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Affiliation(s)
- Marc Schulte
- Abteilung Mikrobiologie and CellNanOs-Center of Cellular Nanoanalytics Osnabrück, Fachbereich Biologie/Chemie, Universität Osnabrück Barbarastr, Osnabrück, Germany
| | - Michael Hensel
- Abteilung Mikrobiologie and CellNanOs-Center of Cellular Nanoanalytics Osnabrück, Fachbereich Biologie/Chemie, Universität Osnabrück Barbarastr, Osnabrück, Germany.
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2
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Dondalska A, Rönnberg E, Ma H, Pålsson SA, Magnusdottir E, Gao T, Adam L, Lerner EA, Nilsson G, Lagerström M, Spetz AL. Amelioration of Compound 48/80-Mediated Itch and LL-37-Induced Inflammation by a Single-Stranded Oligonucleotide. Front Immunol 2020; 11:559589. [PMID: 33101278 PMCID: PMC7554336 DOI: 10.3389/fimmu.2020.559589] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022] Open
Abstract
Numerous inflammatory skin disorders display a high prevalence of itch. The Mas-related G protein coupled receptor X2 (MRGPRX2) has been shown to modulate itch by inducing non-IgE-mediated mast cell degranulation and the release of endogenous inducers of pruritus. Various substances collectively known as basic secretagogues, which include inflammatory peptides and certain drugs, can trigger MRGPRX2 and thereby induce pseudo-allergic reactions characterized by histamine and protease release as well as inflammation. Here, we investigated the capacity of an immunomodulatory single-stranded oligonucleotide (ssON) to modulate IgE-independent mast cell degranulation and, more specifically, its ability to inhibit the basic secretagogues compound 48/80 (C48/80)-and LL-37 in vitro and in vivo. We examined the effect of ssON on MRGPRX2 activation in vitro by measuring degranulation in a human mast cell line (LAD2) and calcium influx in MRGPRX2-transfected HEK293 cells. To determine the effect of ssON on itch, we performed behavioral studies in established mouse models and collected skin biopsies for histological analysis. Additionally, with the use of a rosacea mouse model and RT-qPCR, we investigated the effect on ssON on LL-37-induced inflammation. We reveal that both mast cell degranulation and calcium influx in MRGPRX2 transfected HEK293 cells, induced by the antimicrobial peptide LL-37 and the basic secretagogue C48/80, are effectively inhibited by ssON in a dose-dependent manner. Further, ssON demonstrates a capability to inhibit LL-37 and C48/80 activation in vivo in two mouse models. We show that intradermal injection of ssON in mice is able to block itch induced via C48/80 in a dose-dependent manner. Histological staining revealed that ssON inhibits acute mast cell degranulation in murine skin treated with C48/80. Lastly, we show that ssON treatment ameliorates LL-37-induced inflammation in a rosacea mouse model. Since there is a need for new therapeutics targeting non-IgE-mediated activation of mast cells, ssON could be used as a prospective drug candidate to resolve itch and inflammation in certain dermatoses.
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Affiliation(s)
- Aleksandra Dondalska
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Elin Rönnberg
- Immunology and Allergy Division, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
| | - Haisha Ma
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Sandra Axberg Pålsson
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | | | - Tianle Gao
- Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Lucille Adam
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Ethan A. Lerner
- Department of Dermatology, Cutaneous Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, MA, United States
| | - Gunnar Nilsson
- Immunology and Allergy Division, Department of Medicine, Karolinska Institutet, Karolinska University Hospital, Solna, Sweden
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | | | - Anna-Lena Spetz
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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3
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de la Fuente B, López-García G, Máñez V, Alegría A, Barberá R, Cilla A. Antiproliferative Effect of Bioaccessible Fractions of Four Brassicaceae Microgreens on Human Colon Cancer Cells Linked to Their Phytochemical Composition. Antioxidants (Basel) 2020; 9:E368. [PMID: 32354116 PMCID: PMC7278869 DOI: 10.3390/antiox9050368] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 04/22/2020] [Accepted: 04/27/2020] [Indexed: 12/12/2022] Open
Abstract
The antiproliferative effect of the bioaccessible fractions (BFs) of four hydroponic Brassicaceae microgreens (broccoli, kale, mustard and radish) was evaluated on colon cancer Caco-2 cells vs. normal colon CCD18-Co cells after 24 h treatment with BFs diluted 1:10 v/v in cell culture medium. Their bioactivity was compared with the digestion blank, while the colon cancer chemotherapeutic drug 5-fluorouracil was used as a positive control. Cell viability (mitochondrial enzyme activity assay (MTT test) and Trypan blue test) and mechanisms related to antiproliferative activity (cell cycle, apoptosis/necrosis, mitochondrial membrane potential, reactive oxygen species (ROS) production, Ca2+ and glutathione (GSH) intracellular content) were studied. All microgreen BFs increased ROS and decreased GSH, altering the redox status and causing mitochondrial membrane dissipation followed by a general cell cycle arrest in G2/M and apoptotic cell death via a Ca2+-independent mechanism. As a result, the antioxidant bioactive compounds present in these microgreen species reduced the proliferation of tumoral cells (10 to 12.8% -MTT or 20 to 41.9% -Trypan blue), showing lesser effects with broccoli microgreens, in line with their lower ascorbic acid content and total antioxidant capacity. Therefore, the daily intake of microgreens within a balanced diet could be a preventive nutritional strategy to reduce the burden of chronic degenerative diseases such as colon cancer.
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Affiliation(s)
- Beatriz de la Fuente
- Nutrition and Food Science Area, Faculty of Pharmacy, University of Valencia, Av. Vicent Andrés Estellés s/n, Burjassot, 46100 Valencia, Spain
| | - Gabriel López-García
- Nutrition and Food Science Area, Faculty of Pharmacy, University of Valencia, Av. Vicent Andrés Estellés s/n, Burjassot, 46100 Valencia, Spain
| | - Vicent Máñez
- CIAM (Centro de Innovación Agronómica_Grupo Alimentario Citrus), Av. dels Gremis, Parcela 28. Pol. Ind. Sector 13, Riba-roja de Túria, 46394 Valencia, Spain
| | - Amparo Alegría
- Nutrition and Food Science Area, Faculty of Pharmacy, University of Valencia, Av. Vicent Andrés Estellés s/n, Burjassot, 46100 Valencia, Spain
| | - Reyes Barberá
- Nutrition and Food Science Area, Faculty of Pharmacy, University of Valencia, Av. Vicent Andrés Estellés s/n, Burjassot, 46100 Valencia, Spain
| | - Antonio Cilla
- Nutrition and Food Science Area, Faculty of Pharmacy, University of Valencia, Av. Vicent Andrés Estellés s/n, Burjassot, 46100 Valencia, Spain
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4
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Rogers-Broadway KR, Karydis LI, Dobson RC, Steele AJ. Ex-Vivo Signal Transduction Studies in Chronic Lymphocytic Leukemia. Methods Mol Biol 2019; 1881:1-17. [PMID: 30350193 DOI: 10.1007/978-1-4939-8876-1_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2023]
Abstract
Microenvironmental signaling is pivotal to chronic lymphocytic leukemia (CLL) pathology; therefore understanding how to investigate this pathway by both protein and chemical methods is crucial if we are to investigate and correlate biological changes with therapeutic responses in patients. Herein, we describe the use of western blotting also referred to as immunoblotting as a method that can semiquantitatively evaluate changes in protein expression following receptor engagement; this includes B cell receptor (BCR) signaling following stimulation with anti-IgM (Blunt et al. Clin Cancer Res 23(9):2313-2324, 2017). It is important to note that immunoblotting should always be combined with other quantitative methods such as flow cytometry to confirm activation of these signaling pathways (Aguilar-Hernandez et al. Blood 127(24):3015-3025, 2016).
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MESH Headings
- B-Lymphocytes/metabolism
- Blotting, Western/instrumentation
- Blotting, Western/methods
- Electrophoresis, Polyacrylamide Gel/instrumentation
- Electrophoresis, Polyacrylamide Gel/methods
- Flow Cytometry/instrumentation
- Flow Cytometry/methods
- Gene Expression Regulation, Leukemic
- Humans
- Leukemia, Lymphocytic, Chronic, B-Cell/pathology
- Receptors, Antigen, B-Cell/metabolism
- Signal Transduction
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Affiliation(s)
| | - Laura I Karydis
- Cancer Sciences Unit, Southampton General Hospital, University of Southampton, Southampton, UK
| | - Rachel C Dobson
- Cancer Sciences Unit, Southampton General Hospital, University of Southampton, Southampton, UK
| | - Andrew J Steele
- Cancer Sciences Unit, Southampton General Hospital, University of Southampton, Southampton, UK.
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5
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Syeda SS, Sánchez G, Hong KH, Hawkinson JE, Georg GI, Blanco G. Design, Synthesis, and in Vitro and in Vivo Evaluation of Ouabain Analogues as Potent and Selective Na,K-ATPase α4 Isoform Inhibitors for Male Contraception. J Med Chem 2018; 61:1800-1820. [PMID: 29291372 PMCID: PMC5846083 DOI: 10.1021/acs.jmedchem.7b00925] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
![]()
Na,K-ATPase α4 is a testis-specific
plasma membrane Na+ and K+ transporter expressed
in sperm flagellum.
Deletion of Na,K-ATPase α4 in male mice results in complete
infertility, making it an attractive target for male contraception.
Na,K-ATPase α4 is characterized by a high affinity for the cardiac
glycoside ouabain. With the goal of discovering selective inhibitors
of the Na,K-ATPase α4 and of sperm function, ouabain derivatives
were modified at the glycone (C3) and the lactone (C17) domains. Ouabagenin
analogue 25, carrying a benzyltriazole moiety at C17,
is a picomolar inhibitor of Na,K-ATPase α4, with an outstanding
α4 isoform selectivity profile. Moreover, compound 25 decreased sperm motility in vitro and in vivo and affected sperm
membrane potential, intracellular Ca2+, pH, and hypermotility.
These results proved that the new ouabagenin triazole analogue is
an effective and selective inhibitor of Na,K-ATPase α4 and sperm
function.
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Affiliation(s)
- Shameem Sultana Syeda
- Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy , University of Minnesota , Minneapolis , Minnesota 55414 , United States
| | - Gladis Sánchez
- Department of Molecular and Integrative Physiology , University of Kansas Medical Center , Kansas City , Kansas 66160 , United States
| | - Kwon Ho Hong
- Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy , University of Minnesota , Minneapolis , Minnesota 55414 , United States
| | - Jon E Hawkinson
- Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy , University of Minnesota , Minneapolis , Minnesota 55414 , United States
| | - Gunda I Georg
- Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy , University of Minnesota , Minneapolis , Minnesota 55414 , United States
| | - Gustavo Blanco
- Department of Molecular and Integrative Physiology , University of Kansas Medical Center , Kansas City , Kansas 66160 , United States
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6
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Pazina T, James AM, MacFarlane AW, Bezman NA, Henning KA, Bee C, Graziano RF, Robbins MD, Cohen AD, Campbell KS. The anti-SLAMF7 antibody elotuzumab mediates NK cell activation through both CD16-dependent and -independent mechanisms. Oncoimmunology 2017; 6:e1339853. [PMID: 28932638 DOI: 10.1080/2162402x.2017.1339853] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 06/01/2017] [Accepted: 06/02/2017] [Indexed: 10/19/2022] Open
Abstract
Elotuzumab is a humanized therapeutic monoclonal antibody directed to the surface glycoprotein SLAMF7 (CS1, CRACC, CD319), which is highly expressed on multiple myeloma (MM) tumor cells. Improved clinical outcomes have been observed following treatment of MM patients with elotuzumab in combination with lenalidomide or bortezomib. Previous work showed that elotuzumab stimulates NK cell-mediated antibody-dependent cellular cytotoxicity (ADCC), via Fc-domain engagement with FcγRIIIa (CD16). SLAMF7 is also expressed on NK cells, where it can transmit stimulatory signals. We tested whether elotuzumab can directly activate NK cells via ligation with SLAMF7 on NK cells in addition to targeting ADCC through CD16. We show that elotuzumab strongly promoted degranulation and activation of NK cells in a CD16-dependent manner, and a non-fucosylated form of elotuzumab with higher affinity to CD16 exhibited enhanced potency. Using F(ab')2 or Fc-mutant forms of the antibody, the direct binding of elotuzumab to SLAMF7 alone could not stimulate measurable CD69 expression or degranulation of NK cells. However, the addition of soluble elotuzumab could costimulate calcium signaling responses triggered by multimeric engagement of NKp46 and NKG2D in a CD16-independent manner. Thus, while elotuzumab primarily stimulates NK cells through CD16, it can also transduce effective "trans"-costimulatory signals upon direct engagement with SLAMF7, since these responses did not require direct co-engagement with the activating receptors. Trans-costimulation by elotuzumab has potential to reduce activation thresholds of other NK cell receptors engaging with their ligands on myeloma target cell surfaces, thereby potentially further increasing NK cell responsiveness in patients.
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Affiliation(s)
- Tatiana Pazina
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA, USA.,Federal State Budgetary Scientific Institution "Institute of Experimental Medicine," St. Petersburg, Russia
| | - Ashley M James
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA, USA
| | - Alexander W MacFarlane
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA, USA
| | | | | | | | | | | | - Adam D Cohen
- Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA, USA
| | - Kerry S Campbell
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA, USA
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7
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Theorell J, Bryceson YT. Analysis of Intracellular Ca(2+) Mobilization in Human NK Cell Subsets by Flow Cytometry. Methods Mol Biol 2016; 1441:117-130. [PMID: 27177661 DOI: 10.1007/978-1-4939-3684-7_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In signaling cascades downstream of NK cell activating receptor engagement, Ca(2+) ions are pivotal second messengers for NK cell cytotoxicity as well as cytokine production. Upon cellular activation, intracellular mobilization of Ca(2+) ions initially involves depletion of endoplasmic reticulum stores, leading to subsequent Ca(2+) influx through specific plasma membrane Ca(2+) release activated Ca(2+) channels. Multiple probes and assays for detecting intracellular Ca(2+) concentrations have been developed. With the advance of multiparameter flow cytometry instrumentation, a thorough analysis of signaling in specific NK cell subsets is possible. Here, a flow cytometric method for dynamic measurements of intracellular Ca(2+) concentrations in human NK cells subsets is detailed and discussed. This assay can be further adapted for specific scientific and diagnostic questions, with implications for various immunopathological conditions.
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Affiliation(s)
- Jakob Theorell
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, 14186, Stockholm, Sweden
| | - Yenan T Bryceson
- Center for Infectious Medicine, Department of Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, 14186, Stockholm, Sweden.
- Broegelmann Research Laboratory, Department of Clinical Science, University of Bergen, 5021, Bergen, Norway.
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8
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Selli C, Erac Y, Tosun M. Simultaneous measurement of cytosolic and mitochondrial calcium levels: Observations in TRPC1-silenced hepatocellular carcinoma cells. J Pharmacol Toxicol Methods 2015; 72:29-34. [DOI: 10.1016/j.vascn.2014.12.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 12/15/2014] [Accepted: 12/15/2014] [Indexed: 01/09/2023]
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9
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Yang BC, Pan XJ, Yang ZH, Xiao FJ, Liu XY, Zhu MX, Xie JP. Crotonaldehyde induces apoptosis in alveolar macrophages through intracellular calcium, mitochondria and p53 signaling pathways. J Toxicol Sci 2013; 38:225-35. [DOI: 10.2131/jts.38.225] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Bi-cheng Yang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences,China
- Zhengzhou Tobacco Research Institute of CNTC, China
| | - Xiu-jie Pan
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, China
| | - Zhi-hua Yang
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, China
| | - Feng-jun Xiao
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, China
| | - Xing-yu Liu
- Beijing Work Station, Technology Center of Shanghai Tobacco Corporation, China
| | - Mao-xiang Zhu
- Department of Radiation Toxicology and Oncology, Beijing Institute of Radiation Medicine, China
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10
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Nyakeriga AM, Garg H, Joshi A. TCR-induced T cell activation leads to simultaneous phosphorylation at Y505 and Y394 of p56(lck) residues. Cytometry A 2012; 81:797-805. [PMID: 22674786 DOI: 10.1002/cyto.a.22070] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 04/12/2012] [Accepted: 04/23/2012] [Indexed: 11/11/2022]
Abstract
Biochemical studies have demonstrated that phosphorylation of lymphocyte cell kinase (p56(lck) ) is crucial for activation of signaling cascades following T cell receptor (TCR) stimulation. However, whether phosphorylation/dephosphorylation of the activating or inhibitory tyrosine residues occurs upon activation is controversial. Recent advances in intracellular staining of phospho-epitopes and cytometric analysis, requiring few cells, have opened up novel avenues for the field of immunological signaling. Here, we assessed p56(lck) phosphorylation, using a multiparameter flow-cytometric based detection method following T cell stimulation. Fixation and permeabilization in conjunction with zenon labeling technology and/or fluorescently labeled antibodies against total p56(lck) or cognate phospho-tyrosine (pY) residues or surface receptors were used for detection purposes. Our observations showed that activation of Jurkat or primary human T cells using H(2) O(2) or TCR-induced stimulation led to simultaneous phosphorylation of the activating tyrosine residue, Y394 and the inhibitory tyrosine residue, Y505 of p56(lck) . This was followed by downstream calcium flux and expression of T cell activation markers; CD69 and CD40 ligand (CD40L). However, the extent of measurable activation readouts depended on the optimal stimulatory conditions (temperature and/or stimuli combinations). Treatment of cells with a p56(lck) -specific inhibitor, PP2, abolished phosphorylation at either residue in a dose-dependent manner. Taken together, these observations show that TCR-induced stimulation of T cells led to simultaneous phosphorylation of p56(lck) residues. This implies that dephosphorylation of Y505 is not crucial for p56(lck) activity. Also, it is clear that cytometric analysis provides for a rapid, sensitive, and quantitative method to supplement biochemical studies on p56(lck) signaling pathways in T cells at single cell level.
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Affiliation(s)
- Alice M Nyakeriga
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center, 5001 El Paso Drive, El Paso, Texas 79905, USA.
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11
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Haidari M, Zhang W, Ganjehei L, Ali M, Chen Z. Inhibition of MLC phosphorylation restricts replication of influenza virus--a mechanism of action for anti-influenza agents. PLoS One 2011; 6:e21444. [PMID: 21731751 PMCID: PMC3121769 DOI: 10.1371/journal.pone.0021444] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 05/28/2011] [Indexed: 01/21/2023] Open
Abstract
Influenza A viruses are a severe threat worldwide, causing large epidemics that kill thousands every year. Prevention of influenza infection is complicated by continuous viral antigenic changes. Newer anti-influenza agents include MEK/ERK and protein kinase C inhibitors; however, the downstream effectors of these pathways have not been determined. In this study, we identified a common mechanism for the inhibitory effects of a significant group of anti-influenza agents. Our studies showed that influenza infection activates a series of signaling pathways that converge to induce myosin light chain (MLC) phosphorylation and remodeling of the actin cytoskeleton. Inhibiting MLC phosphorylation by blocking RhoA/Rho kinase, phospholipase C/protein kinase C, and HRas/Raf/MEK/ERK pathways with the use of genetic or chemical manipulation leads to the inhibition of influenza proliferation. In contrast, the induction of MLC phosphorylation enhances influenza proliferation, as does activation of the HRas/Raf/MEK/ERK signaling pathway. This effect is attenuated by inhibiting MLC phosphorylation. Additionally, in intracellular trafficking studies, we found that the nuclear export of influenza ribonucleoprotein depends on MLC phosphorylation. Our studies provide evidence that modulation of MLC phosphorylation is an underlying mechanism for the inhibitory effects of many anti-influenza compounds.
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Affiliation(s)
- Mehran Haidari
- Department of Internal Medicine, Division of Cardiology, University of Texas Health Science Center at Houston, Houston, Texas, United States of America.
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12
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Buslepp J, Kerry SE, Loftus D, Frelinger JA, Appella E, Collins EJ. High affinity xenoreactive TCR:MHC interaction recruits CD8 in absence of binding to MHC. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:373-83. [PMID: 12496422 DOI: 10.4049/jimmunol.170.1.373] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The TCR from a xenoreactive murine cytotoxic T lymphocyte clone, AHIII 12.2, recognizes murine H-2D(b) complexed with peptide p1058 (FAPGFFPYL) as well as human HLA-A2.1 complexed with human self-peptide p1049 (ALWGFFPVL). To understand more about T cell biology and cross-reactivity, the ectodomains of the AHIII 12.2 TCR have been produced in E. coli as inclusion bodies and the protein folded to its native conformation. Flow cytometric and surface plasmon resonance analyses indicate that human p1049/A2 has a significantly greater affinity for the murine AHIII 12.2 TCR than does murine p1058/D(b). Yet, T cell binding and cytolytic activity are independent of CD8 when stimulated with human p1049/A2 as demonstrated with anti-CD8 Abs that block CD8 association with MHC. Even in the absence of direct CD8 binding, stimulation of AHIII 12.2 T cells with "CD8-independent" p1049/A2 produces p56(lck) activation and calcium flux. Confocal fluorescence microscopy and fluorescence resonance energy transfer flow cytometry demonstrate CD8 is recruited to the site of TCR:peptide MHC binding. Taken together, these results indicate that there exists another mechanism for recruitment of CD8 during high affinity TCR:peptide MHC engagement.
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MESH Headings
- Animals
- Antigen Presentation/genetics
- Antigens, Heterophile/metabolism
- CD8 Antigens/metabolism
- CD8 Antigens/physiology
- CHO Cells
- Cell Line
- Clone Cells
- Cricetinae
- Cytotoxicity, Immunologic/genetics
- H-2 Antigens/genetics
- H-2 Antigens/metabolism
- HLA-A2 Antigen/genetics
- HLA-A2 Antigen/metabolism
- Histocompatibility Antigen H-2D
- Humans
- Lymphocyte Activation/genetics
- Mice
- Mice, Inbred C57BL
- Oligopeptides/immunology
- Oligopeptides/metabolism
- Protein Binding/genetics
- Protein Binding/immunology
- Receptors, Antigen, T-Cell/biosynthesis
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/metabolism
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/metabolism
- Signal Transduction/genetics
- Signal Transduction/immunology
- Surface Plasmon Resonance
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
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Affiliation(s)
- Jennifer Buslepp
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
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13
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Ono K, Wang X, Han J. Resistance to tumor necrosis factor-induced cell death mediated by PMCA4 deficiency. Mol Cell Biol 2001; 21:8276-88. [PMID: 11713265 PMCID: PMC99993 DOI: 10.1128/mcb.21.24.8276-8288.2001] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2001] [Accepted: 09/12/2001] [Indexed: 11/20/2022] Open
Abstract
We used retrovirus insertion-mediated random mutagenesis to generate tumor necrosis factor (TNF)-resistant lines from L929 cells. Using this approach, we discovered that the plasma membrane calcium ATPase 4 (PMCA4) is required for TNF-induced cell death in L929 cells. Under basal conditions, PMCA4-deficient (PMCA(mut)) cells have a normal phenotype. However, stimulation with TNF induces an abnormal increase in the intracellular calcium concentration ([Ca(2+)](i)). The substantially elevated [Ca(2+)](i) caused resistance to TNF-induced cell death. We found that an increase in the total volume of acidic compartments (VAC), mainly constituted by lysosomes, is a common event in cell death caused by a variety of agonists. The increased [Ca(2+)](i) in PMCA(mut) cells promoted lysosome exocytosis, which, at least in part, accounted for the inhibition of TNF-induced increase in VAC and cell death. Promoting lysosome exocytosis by calcium inhibited TNF-induced cell death in wild-type L929 cells, while inhibition of lysosome exocytosis or increase of VAC by sucrose restored the sensitivity of PMCA(mut) cells to TNF-induced cell death. Thus, increase of the volume of acidic compartment is a part of the cell death process, and the antideath effect of calcium is mediated, at least in part, by inhibition of the TNF-induced increase in VAC.
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Affiliation(s)
- K Ono
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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