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Scott AL, Zhang M, Nurse CA. Enhanced BDNF signalling following chronic hypoxia potentiates catecholamine release from cultured rat adrenal chromaffin cells. J Physiol 2016; 593:3281-99. [PMID: 26095976 DOI: 10.1113/jp270725] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 06/06/2015] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS We investigated the role of the neurotrophin BDNF signalling via the TrkB receptor in rat adrenomedullary chromaffin cells (AMCs) exposed to normoxia (Nox; 21% O2) and chronic hypoxia (CHox; 2% O2) in vitro for ∼ 48 h. TrkB receptor expression was upregulated in primary AMCs and in immortalized chromaffin (MAH) cells exposed to CHox; this effect was absent in MAH cells deficient in the transcription factor, hypoxia inducible factor (HIF)-2α. Relative to normoxic controls, activation of the TrkB receptor in chronically hypoxic AMCs led to a marked increase in membrane excitability, intracellular [Ca(2+)], and catecholamine secretion. The BDNF-induced rise of intracellular [Ca(2+)] in CHox cells was sensitive to the selective T-type Ca(2+) channel blocker TTA-P2 and tetrodotoxin (TTX), suggesting key roles of low threshold T-type Ca(2+) and voltage-gated Na(+) channels in the signalling pathway. Environmental stressors, including chronic hypoxia, enhance the ability of adrenomedullary chromaffin cells (AMCs) to secrete catecholamines; however, the underlying molecular mechanisms remain unclear. Here, we investigated the role of brain-derived neurotrophic factor (BDNF) signalling in rat AMCs exposed to chronic hypoxia. In rat adrenal glands, BDNF and its tropomyosin-related kinase B (TrkB) receptor are highly expressed in the cortex and medulla, respectively. Exposure of AMCs to chronic hypoxia (2% O2; 48 h) in vitro caused a significant increase to TrkB mRNA expression. A similar increase was observed in an immortalized chromaffin cell line (MAH cells); however, it was absent in MAH cells deficient in the transcription factor HIF-2α. A specific TrkB agonist, 7,8-dihydroxyflavone (7,8-DHF), stimulated quantal catecholamine secretion from chronically hypoxic (CHox; 2% O2) AMCs to a greater extent than normoxic (Nox; 21% O2) controls. Activation of TrkB by BDNF or 7,8-DHF increased intracellular Ca(2+) ([Ca(2+)]i), an effect that was significantly larger in CHox cells. The 7,8-DHF-induced [Ca(2+)]i rise was sensitive to the tyrosine kinase inhibitor K252a and nickel (2 mm), but not the Ca(2+) store-depleting agent cyclopiazonic acid. Blockade of T-type calcium channels with TTA-P2 (1 μm) or voltage-gated Na(+) channels with TTX inhibited BDNF-induced [Ca(2+)]i increases. BDNF also induced a dose-dependent enhancement of action potential firing in CHox cells. These data demonstrate that during chronic hypoxia, enhancement of BDNF-TrkB signalling increases voltage-dependent Ca(2+) influx and catecholamine secretion in chromaffin cells, and that T-type Ca(2+) channels play a key role in the signalling pathway.
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Affiliation(s)
- Angela L Scott
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - Min Zhang
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
| | - Colin A Nurse
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4K1, Canada
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Herbáth M, Papp K, Balogh A, Matkó J, Prechl J. Exploiting fluorescence for multiplex immunoassays on protein microarrays. Methods Appl Fluoresc 2014; 2:032001. [PMID: 29148470 DOI: 10.1088/2050-6120/2/3/032001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Protein microarray technology is becoming the method of choice for identifying protein interaction partners, detecting specific proteins, carbohydrates and lipids, or for characterizing protein interactions and serum antibodies in a massively parallel manner. Availability of the well-established instrumentation of DNA arrays and development of new fluorescent detection instruments promoted the spread of this technique. Fluorescent detection has the advantage of high sensitivity, specificity, simplicity and wide dynamic range required by most measurements. Fluorescence through specifically designed probes and an increasing variety of detection modes offers an excellent tool for such microarray platforms. Measuring for example the level of antibodies, their isotypes and/or antigen specificity simultaneously can offer more complex and comprehensive information about the investigated biological phenomenon, especially if we take into consideration that hundreds of samples can be measured in a single assay. Not only body fluids, but also cell lysates, extracted cellular components, and intact living cells can be analyzed on protein arrays for monitoring functional responses to printed samples on the surface. As a rapidly evolving area, protein microarray technology offers a great bulk of information and new depth of knowledge. These are the features that endow protein arrays with wide applicability and robust sample analyzing capability. On the whole, protein arrays are emerging new tools not just in proteomics, but glycomics, lipidomics, and are also important for immunological research. In this review we attempt to summarize the technical aspects of planar fluorescent microarray technology along with the description of its main immunological applications.
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Affiliation(s)
- Melinda Herbáth
- Department of Immunology, Eötvös Loránd University, Budapest, 1117 Hungary
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Herbáth M, Szekeres Z, Kövesdi D, Papp K, Erdei A, Prechl J. Coadministration of antigen-conjugated and free CpG: effects of in vitro and in vivo interactions in a murine model. Immunol Lett 2014; 160:178-85. [PMID: 24565977 DOI: 10.1016/j.imlet.2014.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 02/11/2014] [Accepted: 02/12/2014] [Indexed: 01/20/2023]
Abstract
CpG oligodeoxynucleotides (CpG) are widely studied as promising adjuvants in vaccines against a range of diseases including infection, cancer or allergy. Conjugating antigen to CpG has been shown to potentiate the adjuvant effect via enhancing antigen uptake and danger signaling by the very same cell. In the present study, using biotinylated CpG and streptavidin as a model system, we demonstrate that CpG motif containing free and antigen-conjugated oligonucleotides do not compete in terms of cell activation via TLR9, but do compete for cellular uptake. Antigen-conjugated CpG enhances cellular association and uptake of the antigen by antigen-presenting cells (APC) and T cells. Free CpG efficiently competes with antigen-CpG conjugates in BMDC and T cells, but shows weak or no competition in B cells that have higher TLR9 expression. Vaccination with antigen-conjugated CpG or with a mixture of antigen and CpG elevates the level of antigen-specific antibodies but co-administration of CpG-antigen conjugates and free CpG adversely effects immunogenicity. These observations may help optimize CpG-based vaccine formulation.
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Affiliation(s)
- Melinda Herbáth
- Department of Immunology, Eötvös Loránd University, 1/C Pázmány Péter sétány, Budapest 1117, Hungary.
| | - Zsuzsanna Szekeres
- MTA-ELTE Immunology Research Group, 1/C Pázmány Péter sétány, Budapest 1117, Hungary
| | - Dorottya Kövesdi
- Department of Immunology, Eötvös Loránd University, 1/C Pázmány Péter sétány, Budapest 1117, Hungary
| | - Krisztián Papp
- MTA-ELTE Immunology Research Group, 1/C Pázmány Péter sétány, Budapest 1117, Hungary
| | - Anna Erdei
- Department of Immunology, Eötvös Loránd University, 1/C Pázmány Péter sétány, Budapest 1117, Hungary; MTA-ELTE Immunology Research Group, 1/C Pázmány Péter sétány, Budapest 1117, Hungary
| | - József Prechl
- MTA-ELTE Immunology Research Group, 1/C Pázmány Péter sétány, Budapest 1117, Hungary
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Zhou M, Li LH, Peng H, Li R, Feng CC, Xu WD, Leng RX, Pan HF, Ye DQ. Decreased ITGAM and FcγRIIIA mRNA expression levels in peripheral blood mononuclear cells from patients with systemic lupus erythematosus. Clin Exp Med 2013; 14:269-74. [PMID: 23708937 DOI: 10.1007/s10238-013-0240-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 05/10/2013] [Indexed: 11/29/2022]
Abstract
Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease with complex genetic predisposing factors involved. ITGAM and FCγRIIIA are two kinds of immune complex clearance molecules. The variants in ITGAM and FCγRIIIA genes have been confirmed to be associated with SLE. The aim of this study is to investigate the association of mRNA expression levels of ITGAM and FCγRIIIA with SLE. Real-time transcription-polymerase chain reaction analysis (RT-PCR) was used to determine the expression levels of ITGAM and FCγRIIIA mRNA in peripheral blood mononuclear cells (PBMC) from 60 patients with SLE and 60 healthy controls. Flow cytometry was used to measure the expression level of ITGAM and FcγRIIIA from 30 SLE patients and 30 healthy controls. The expression levels of ITGAM mRNA was significantly decreased in SLE patients compared with healthy controls (P = 0.007). Patients with arthritis had higher ITGAM mRNA level than those without arthritis (P = 0.029). The expression level of FCγRIIIA mRNA in SLE patients was significantly lower than that of healthy controls (P = 0.001). Decreased expression level of FCγRIIIA mRNA was also found in patients with LN compared with those without LN (P = 0.015). The level of ITGAM mRNA in patients with anti-SSB positive, anti-RNP positive, complement reduction and increased IgG was significantly reduced. No significant correlation was found between ITGAM and FcγRIIIA mRNA expression level in SLE patients (r = -0.019, P = 0.882). Expression of ITGAM protein in T cells, neutrophil and monocyte of SLE patients was significantly lower than healthy controls (P < 0.05). For FcγRIIIA protein expression in monocyte and NK cells, there were no significant difference between SLE patients and healthy controls (P > 0.05). The altered expression levels of ITGAM and FCγRIIIA mRNA in SLE patients and their correlations with clinical data suggest that ITGAM and FCγRIIIA may play a role in this disease.
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Affiliation(s)
- Mo Zhou
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, People's Republic of China
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Gesheva V, Szekeres Z, Mihaylova N, Dimitrova I, Nikolova M, Erdei A, Prechl J, Tchorbanov A. Generation of gene-engineered chimeric DNA molecules for specific therapy of autoimmune diseases. Hum Gene Ther Methods 2012; 23:357-65. [PMID: 23075110 PMCID: PMC4015069 DOI: 10.1089/hgtb.2012.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Accepted: 10/15/2012] [Indexed: 12/20/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the development of self-reactive B and T cells and autoantibody production. In particular, double-stranded DNA-specific B cells play an important role in lupus progression, and their selective elimination is a reasonable approach for effective therapy of SLE. DNA-based vaccines aim at the induction of immune response against the vector-encoded antigen. Here, we are exploring, as a new DNA-based therapy of SLE, a chimeric DNA molecule encoding a DNA-mimotope peptide, and the Fv but not the immunogenic Fc fragment of an FcγRIIb-specific monoclonal antibody. This DNA construct was inserted in the expression vector pNut and used as a naked DNA vaccine in a mouse model of lupus. The chimeric DNA molecule can be expressed in eukaryotic cells and cross-links cell surface receptors on DNA-specific B cells, delivering an inhibitory intracellular signal. Intramuscular administration of the recombinant DNA molecule to lupus-prone MRL/lpr mice prevented increase in IgG anti-DNA antibodies and was associated with a low degree of proteinuria, modulation of cytokine profile, and suppression of lupus nephritis.
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Affiliation(s)
- Vera Gesheva
- Institute of Microbiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Szarka E, Neer Z, Balogh P, Adori M, Angyal A, Prechl J, Kiss E, Kövesdi D, Sármay G. Exacerbation of collagen induced arthritis by Fcγ receptor targeted collagen peptide due to enhanced inflammatory chemokine and cytokine production. Biologics 2012; 6:101-15. [PMID: 22532778 PMCID: PMC3333823 DOI: 10.2147/btt.s29749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Antibodies specific for bovine type II collagen (CII) and Fcγ receptors play a major role in collagen-induced arthritis (CIA), a mouse model of rheumatoid arthritis (RA). Our aim was to clarify the mechanism of immune complex-mediated inflammation and modulation of the disease. CII pre-immunized DBA/1 mice were intravenously boosted with extravidin coupled biotinylated monomeric CII-peptide epitope (ARGLTGRPGDA) and its complexes with biotinylated FcγRII/III specific single chain Fv (scFv) fragment. Disease scores were monitored, antibody titers and cytokines were determined by ELISA, and binding of complexes was detected by flow cytometry and immune histochemistry. Cytokine and chemokine secretion was monitored by protein profiler microarray. When intravenously administered into collagen-primed DBA/1 mice, both CII-peptide and its complex with 2.4G2 scFv significantly accelerated CIA and increased the severity of the disease, whereas the monomeric peptide and monomeric 2.4G2 scFv had no effect. FcγRII/III targeted CII-peptide complexes bound to marginal zone macrophages and dendritic cells, and significantly elevated the synthesis of peptide-specific IgG2a. Furthermore, CII-peptide containing complexes augmented the in vivo secretion of cytokines, including IL-10, IL-12, IL-17, IL-23, and chemokines (CXCL13, MIP-1, MIP-2). These data indicate that complexes formed by the CII-peptide epitope aggravate CIA by inducing the secretion of chemokines and the IL-12/23 family of pro-inflammatory cytokines. Taken together, these results suggest that the in vivo emerging immune complexes formed with autoantigen(s) may trigger the IL-12/23 dependent pathways, escalating the inflammation in RA. Thus blockade of these cytokines may be beneficial to downregulate immune complex-induced inflammation in autoimmune arthritis.
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Affiliation(s)
- Eszter Szarka
- Department of Immunology, Eötvös Loránd University, 1117 Budapest
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Modulation of the humoral immune response by targeting CD40 and FcγRII/III; delivery of soluble but not particulate antigen to CD40 enhances antibody responses with a Th1 bias. Mol Immunol 2011; 49:155-62. [DOI: 10.1016/j.molimm.2011.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 08/08/2011] [Accepted: 08/09/2011] [Indexed: 12/25/2022]
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