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Shao L, Yang M, Sun T, Xia H, Du D, Li X, Jie Z. Role of solute carrier transporters in regulating dendritic cell maturation and function. Eur J Immunol 2024; 54:e2350385. [PMID: 38073515 DOI: 10.1002/eji.202350385] [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] [Received: 07/02/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 02/27/2024]
Abstract
Dendritic cells (DCs) are specialized antigen-presenting cells that initiate and regulate innate and adaptive immune responses. Solute carrier (SLC) transporters mediate diverse physiological functions and maintain cellular metabolite homeostasis. Recent studies have highlighted the significance of SLCs in immune processes. Notably, upon activation, immune cells undergo rapid and robust metabolic reprogramming, largely dependent on SLCs to modulate diverse immunological responses. In this review, we explore the central roles of SLC proteins and their transported substrates in shaping DC functions. We provide a comprehensive overview of recent studies on amino acid transporters, metal ion transporters, and glucose transporters, emphasizing their essential contributions to DC homeostasis under varying pathological conditions. Finally, we propose potential strategies for targeting SLCs in DCs to bolster immunotherapy for a spectrum of human diseases.
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Affiliation(s)
- Lin Shao
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, China
- School of Life Sciences, Fudan University, Shanghai, China
| | - Mengxin Yang
- School of Public Health, Xiamen University, Xiamen, Fujian, China
| | - Tao Sun
- Department of Laboratory Medicine, The First Affiliated Hospital, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Haotang Xia
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian, China
| | - Dan Du
- Department of Stomatology, School of Medicine, Xiamen University, Xiamen, Fujian, China
- Cancer Research Center, School of Medicine, Xiamen University, Xiamen, Fujian, China
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian, China
| | - Xun Li
- Department of Laboratory Medicine, The First Affiliated Hospital, School of Medicine, Xiamen University, Xiamen, Fujian, China
| | - Zuliang Jie
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian, China
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Navarro-Pérez M, Capera J, Benavente-Garcia A, Cassinelli S, Colomer-Molera M, Felipe A. Kv1.3 in the spotlight for treating immune diseases. Expert Opin Ther Targets 2024; 28:67-82. [PMID: 38316438 DOI: 10.1080/14728222.2024.2315021] [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] [Received: 09/28/2023] [Accepted: 02/02/2024] [Indexed: 02/07/2024]
Abstract
INTRODUCTION Kv1.3 is the main voltage-gated potassium channel of leukocytes from both the innate and adaptive immune systems. Channel function is required for common processes such as Ca2+ signaling but also for cell-specific events. In this context, alterations in Kv1.3 are associated with multiple immune disorders. Excessive channel activity correlates with numerous autoimmune diseases, while reduced currents result in increased cancer prevalence and immunodeficiencies. AREAS COVERED This review offers a general view of the role of Kv1.3 in every type of leukocyte. Moreover, diseases stemming from dysregulations of the channel are detailed, as well as current advances in their therapeutic research. EXPERT OPINION Kv1.3 arises as a potential immune target in a variety of diseases. Several lines of research focused on channel modulation have yielded positive results. However, among the great variety of specific channel blockers, only one has reached clinical trials. Future investigations should focus on developing simpler administration routes for channel inhibitors to facilitate their entrance into clinical trials. Prospective Kv1.3-based treatments will ensure powerful therapies while minimizing undesired side effects.
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Affiliation(s)
- María Navarro-Pérez
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Jesusa Capera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
- The Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology & Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Anna Benavente-Garcia
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Silvia Cassinelli
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Magalí Colomer-Molera
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
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Nghia VX, Giang NV, Canh NX, Ha NH, Duong NT, Hoang NH, Xuan NT. Stimulation of dendritic cell functional maturation by capsid protein from chikungunya virus. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2020; 23:1268-1274. [PMID: 33149858 PMCID: PMC7585544 DOI: 10.22038/ijbms.2020.40386.9558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Objective(s): Chikungunya virus (ChikV) infection is characterized by persistent infection in joints and lymphoid organs. The ChikV Capsid protein plays an important role in regulating virus replication. In this study, we hypothesized that capsid protein may stimulate dendritic cell (DC) activation and maturation and trigger an inflammatory response in mice. Materials and Methods: Mice were intraperitoneally injected with capsid protein and examined for changes in immunophenotype in lymph nodes (LNs). Next, DCs were treated with capsid protein or LPS and then expression of maturation markers, cytokine production, and ability to stimulate CD4+ T cells in allo-MLR were analyzed. Results: Injection of mice with capsid protein led to recruitment of myeloid cells and increased activation of T lymphocytes in LNs. Importantly, treatment of DCs with capsid protein prolonged the activation of IKB-α and up-regulated the number of CD11c+CD86+DCs and release of TNF-α and IL-12p70 as well as reducing DC apoptosis, all effects were abolished in the presence of Bay 11-7082. In addition, IL-2 production was higher by CD4+ T cells stimulated with capsid-treated as compared with LPS-induced DCs. Conclusion: The observations revealed that capsid protein participates in the regulation of NF-κB signaling and maturation of DCs.
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Affiliation(s)
- Vu Xuan Nghia
- Department of Pathophysiology, Vietnam Military Medical University, Ha Dong, Hanoi, Vietnam
| | - Nguyen Van Giang
- Faculty of Biotechnology, Vietnam National University of Agriculture, Gia Lam, Hanoi, Vietnam
| | - Nguyen Xuan Canh
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam
| | - Nguyen Hai Ha
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Nguyen Thuy Duong
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Nguyen Huy Hoang
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Nguyen Thi Xuan
- Institute of Genome Research, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam.,Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam
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Xuan NT, Toan NL, Mao CV, Vuong NB, Giang NT, Hoang NH. Regulation of dendritic cell function by A20 through high glucose-induced Akt2 signaling. J Recept Signal Transduct Res 2019; 39:434-441. [DOI: 10.1080/10799893.2019.1690511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Nguyen Thi Xuan
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
| | - Nguyen Linh Toan
- Department of Pathophysiology, Vietnam Military Medical University, Hanoi, Vietnam
| | - Can Van Mao
- Department of Pathophysiology, Vietnam Military Medical University, Hanoi, Vietnam
| | - Nguyen Ba Vuong
- 103 Military Hospital, Vietnam Military Medical University, Hanoi, Vietnam
| | | | - Nguyen Huy Hoang
- Institute of Genome Research, Vietnam Academy of Science and Technology, Hanoi, Vietnam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
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Li M, Xi P, Xu Y, Wang Z, Han X, Ren W, Phouthapane V, Miao J. Taurine Attenuates Streptococcus uberis-Induced Bovine Mammary Epithelial Cells Inflammation via Phosphoinositides/Ca 2+ Signaling. Front Immunol 2019; 10:1825. [PMID: 31447841 PMCID: PMC6692464 DOI: 10.3389/fimmu.2019.01825] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 07/18/2019] [Indexed: 12/18/2022] Open
Abstract
Taurine may alleviate the inflammatory injury induced by Streptococcus uberis (S. uberis) infection by regulating intracellular Ca2+ levels. However, the underlying mechanisms remain unclear. Infection leads to subversion of phosphoinositides (PIs) which are closely related to Ca2+ signaling. In order to investigate whether taurine regulates inflammation by means of PIs/ Ca2+ systems, competitive inhibitors of taurine (β-alanine) siTauT, siPAT1, siPLC, siCaN, siPKC, and inhibitors of PLC (U73122), PKC (RO31-8220), and CaN (FK 506) were used. The results indicate that taurine transfers the extracellular nutrient signal for intercellular innate immunity to phosphoinositides without a need to enter the cytoplasm while regulating intracellular Ca2+ levels during inflammation. Both the Ca2+-PKCα-NF-κB, and Ca2+-CaM-CaN-NFAT signaling pathways of S. uberis infection and the regulatory roles of taurine follow activation of PIs/Ca2+ systems. These data increase our understanding on the mechanisms of multifunctional nutrient, taurine attenuated inflammatory responses caused by S. uberis infection, and provide theoretical support for the prevention of this disease.
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Affiliation(s)
- Ming Li
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Panpan Xi
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Yuanyuan Xu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Zhenglei Wang
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Xiangan Han
- Chinese Academy of Agricultural Sciences, Shanghai Veterinary Research Institute, Shanghai, China
| | - Wenkai Ren
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, Subtropical Institute of Animal Nutrition and Feed, South China Agricultural University, Guangzhou, China
| | - Vanhnaseng Phouthapane
- Biotechnology and Ecology Institute, Ministry of Science and Technology, Vientiane, Laos
| | - Jinfeng Miao
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
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Leukocytic toll-like receptor 2 knockout protects against diabetes-induced cardiac dysfunction. Biochem Biophys Res Commun 2018; 506:668-673. [PMID: 30454704 DOI: 10.1016/j.bbrc.2018.10.082] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 10/13/2018] [Indexed: 12/26/2022]
Abstract
Diabetic cardiomyopathy is characterized by the deterioration of the myocardial function. Emerging evidences have indicated that leukocytic toll-like receptor 2 (TLR2) played an important role in the development of diabetic cardiomyopathy. Our study aimed to investigate whether TLR2 knockout (KO) exerted a cardioprotective effect in vivo. The establishment of diabetes model was set up in mice via intraperitoneal injection of streptozotocin (STZ). Results demonstrated that blocking of TLR2 significantly suppressed the enhanced left ventricular end-diastolic dimension (LVEDD), left ventricular end systolic diameter (LVESD) and the reduced the heart rate in diabetic cardiomyopathy mice. The decreased resting cell length, PS, TPS and + dL/dt while increased TR90 and - dL/dt caused by diabetic cardiomyopathy were remarkably inhibited by TLR2 KO. Besides that, the alleviated ΔFFI (360/380), decreased SERCA2a and p-NFATc3 expressions, extended Ca2+ decay time and elevated Calcineurin A induced by diabetic cardiomyopathy were vastly repressed by TLR2 KO in cardiocytes. Moreover, TLR2 gene silence could ameliorate oxidative stress-induced apoptosis, evidences were the up-regulated superoxide generation and Bax/Bcl-2 expression while restrained GSH/GSSG ratio caused by diabetic cardiomyopathy were tremendously repressed in TLR2 KO mice. Furthermore, blocking of TLR2 remarkably attenuated the augmented fibrosis areas of heart tissues in mice with diabetic cardiomyopathy. The result of the enhanced α-SMA and collagenⅠ caused by diabetic cardiomyopathy were suppressed in heart tissues of TLR2 KO mice further validate it. All in all, our study demonstrated that diabetes-induced cardiac dysfunction could be attenuated by TLR2 KO.
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Dai B, Zhang J, Liu M, Lu J, Zhang Y, Xu Y, Miao J, Yin Y. The role of Ca(2+) mediated signaling pathways on the effect of taurine against Streptococcus uberis infection. Vet Microbiol 2016; 192:26-33. [PMID: 27527761 DOI: 10.1016/j.vetmic.2016.06.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 05/20/2016] [Accepted: 06/21/2016] [Indexed: 01/03/2023]
Abstract
To provide insight into the mechanisms of taurine attenuation of pro-inflammatory response in mouse mammary epithelial cell line (EpH4-Ev, purchased by ATCC, USA) after Streptococcus uberis (S. uberis, 0140J) challenge, we infected MECs with S. uberis (2.5×10(7)cfumL(-1), MOI=10) for 3h and quantified changes in TLR-2 and calcium (Ca(2+)) mediated signaling pathways. The results indicate that S. uberis infection significantly increases the expression of TLR-2, intracellular Ca(2+) levels, PLC-γ1 and PKC-α, the activities of transcription factors NF-κB and NFAT, and related cytokines (TNF-α, IL-1β, IL-6, G-CSF, IL-2, KC, IL-15, FasL, MCP-1, and LIX) in culture supernatants. Taurine administration downregulated all these indices, the activities of NF-κB and NFAT. Cytokine secretions were similar using special PKC inhibitor Go 6983 and NFAT inhibitor VIVIT. Our data indicate that S. uberis infection induces pro-inflammatory response of MECs through a TLR-2 mediated signaling pathway. In addition, taurine can prevent MEC damage by affecting both PLC-γ1-Ca(2+)-PKC-α-NF-κB and PLC-γ1-Ca(2+)-NFATs signaling pathways. This is the first report to demonstrate the mechanisms of taurine attenuated pro-inflammatory response in MECs after S. uberis challenge.
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Affiliation(s)
- Bin Dai
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Jinqiu Zhang
- National Research Center for Veterinary Vaccine Engineering and Technology of China, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Ming Liu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Jinye Lu
- Jiangsu Agri-animal Husbandry Vocational College, Taizhou 225300, China
| | - Yuanshu Zhang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Yuanyuan Xu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China
| | - Jinfeng Miao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
| | - Yulong Yin
- Chinese Academy of Science, Institute of Subtropical Agriculture, Research Center for Healthy Breeding Livestock & Poultry, Hunan Engineering & Research Center for Animal & Poultry Science, Key Laboratory of Agroecology in Subtropical Region, Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South-Central China, Ministry of Agriculture, Changsha 410125, China
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Son A, Shin DM, Hong JH. Peptidoglycan Induces the Production of Interleukin-8 via Calcium Signaling in Human Gingival Epithelium. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2014; 19:51-7. [PMID: 25605997 PMCID: PMC4297762 DOI: 10.4196/kjpp.2015.19.1.51] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 11/27/2014] [Accepted: 12/01/2014] [Indexed: 02/06/2023]
Abstract
The etiology of periodontal disease is multifactorial. Exogenous stimuli such as bacterial pathogens can interact with toll-like receptors to activate intracellular calcium signaling in gingival epithelium and other tissues. The triggering of calcium signaling induces the secretion of pro-inflammatory cytokines such as interleukin-8 as part of the inflammatory response; however, the exact mechanism of calcium signaling induced by bacterial toxins when gingival epithelial cells are exposed to pathogens is unclear. Here, we investigate calcium signaling induced by bacteria and expression of inflammatory cytokines in human gingival epithelial cells. We found that peptidoglycan, a constituent of gram-positive bacteria and an agonist of toll-like receptor 2, increases intracellular calcium in a concentration-dependent manner. Peptidoglycan-induced calcium signaling was abolished by treatment with blockers of phospholipase C (U73122), inositol 1,4,5-trisphosphate receptors, indicating the release of calcium from intracellular calcium stores. Peptidoglycan-mediated interleukin-8 expression was blocked by U73122 and 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl ester). Moreover, interleukin-8 expression was induced by thapsigargin, a selective inhibitor of the sarco/endoplasmic reticulum calcium ATPase, when thapsigargin was treated alone or co-treated with peptidoglycan. These results suggest that the gram-positive bacterial toxin peptidoglycan induces calcium signaling via the phospholipase C/inositol 1,4,5-trisphosphate pathway, and that increased interleukin-8 expression is mediated by intracellular calcium levels in human gingival epithelial cells.
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Affiliation(s)
- Aran Son
- Department of Oral Biology, Yonsei University College of Dentistry, Seoul 120-752, Korea. ; BK21 PLUS Project, Yonsei University College of Dentistry, Seoul 120-752, Korea
| | - Dong Min Shin
- Department of Oral Biology, Yonsei University College of Dentistry, Seoul 120-752, Korea. ; BK21 PLUS Project, Yonsei University College of Dentistry, Seoul 120-752, Korea
| | - Jeong Hee Hong
- Department of Physiology, Graduate School of Medicine, Gachon University, Incheon 406-799, Korea
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Towhid ST, Nega M, Schmidt EM, Schmid E, Albrecht T, Münzer P, Borst O, Götz F, Lang F. Stimulation of platelet apoptosis by peptidoglycan from Staphylococcus aureus 113. Apoptosis 2013; 17:998-1008. [PMID: 22752708 DOI: 10.1007/s10495-012-0718-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Peptidoglycan (PGN), a component of bacterial cell wall and belonging to "Microbe-Associated Molecular Patterns" (MAMP) triggers host reactions contributing to the pathophysiology of infectious disease. Host cell responses to PGN exposure include apoptosis. Bacterial infections may result in activation of blood platelets and thrombocytopenia. The present study explored, whether HPLC-purified fractions of PGNs from Staphylococcus aureus 113 triggers apoptosis of platelets. To this end platelets were exposed to PGN fractions and annexin-V binding determined to depict cell membrane scrambling, DiOC6 fluorescence to estimate depolarization of mitochondrial potential, Fluo-3AM staining for intracellular Ca(2+) activity ([Ca(2+)](i)) and immunofluorescence to quantify protein abundance of active caspase-3. As a result, a 30 min exposure to monomeric fraction (mPGN) (≥50 ng/ml) was followed by annexin-V binding, paralleled by increase of [Ca(2+)](i), mitochondrial depolarization, caspase-3 activation and integrin α(IIb)β(3) upregulation. The annexin-V binding was significantly blunted by anti-TLR-2 antibodies, in absence of extracellular Ca(2+), and by pancaspase inhibitor zVAD-FMK (1 μM). In conclusion, PGN triggers apoptosis of platelets in activation-dependent manner, characterized by mitochondrial depolarization, caspase-3 activation and cell membrane scrambling.
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Affiliation(s)
- Syeda T Towhid
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076, Tübingen, Germany
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Shumilina E, Nurbaeva MK, Yang W, Schmid E, Szteyn K, Russo A, Heise N, Leibrock C, Xuan NT, Faggio C, Kuro-o M, Lang F. Altered regulation of cytosolic Ca²⁺ concentration in dendritic cells from klotho hypomorphic mice. Am J Physiol Cell Physiol 2013; 305:C70-7. [PMID: 23596175 DOI: 10.1152/ajpcell.00355.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The function of dendritic cells (DCs), antigen-presenting cells regulating naïve T-cells, is regulated by cytosolic Ca²⁺ concentration ([Ca²⁺]i). [Ca²⁺]i is increased by store-operated Ca²⁺ entry and decreased by K⁺-independent (NCX) and K⁺-dependent (NCKX) Na⁺/Ca²⁺ exchangers. NCKX exchangers are stimulated by immunosuppressive 1,25-dihydroxyvitamin D3 [1,25(OH)₂D₃], the biologically active form of vitamin D. Formation of 1,25(OH)₂D₃ is inhibited by the antiaging protein Klotho. Thus 1,25(OH)₂D₃ plasma levels are excessive in Klotho-deficient mice (klothohm). The present study explored whether Klotho deficiency modifies [Ca²⁺]i regulation in DCs. DCs were isolated from the bone marrow of klothohm mice and wild-type mice (klotho+/+) and cultured for 7-9 days with granulocyte-macrophage colony-stimulating factor. According to major histocompatibility complex II (MHC II) and CD86 expression, differentiation and lipopolysaccharide (LPS)-induced maturation were similar in klothohm DCs and klotho+/+ DCs. However, NCKX1 membrane abundance and NCX/NCKX-activity were significantly enhanced in klothohm DCs. The [Ca²⁺]i increase upon acute application of LPS (1 μg/ml) was significantly lower in klothohm DCs than in klotho+/+ DCs, a difference reversed by the NCKX blocker 3',4'-dichlorobenzamyl (DBZ; 10 μM). CCL21-dependent migration was significantly less in klothohm DCs than in klotho+/+ DCs but could be restored by DBZ. NCKX activity was enhanced by pretreatment of klotho+/+ DC precursors with 1,25(OH)₂D₃ the first 2 days after isolation from bone marrow. Feeding klothohm mice a vitamin D-deficient diet decreased NCKX activity, augmented LPS-induced increase of [Ca²⁺]i, and enhanced migration of klothohm DCs, thus dissipating the differences between klothohm DCs and klotho+/+ DCs. In conclusion, Klotho deficiency upregulates NCKX1 membrane abundance and Na⁺/Ca²⁺-exchange activity, thus blunting the increase of [Ca²⁺]i following LPS exposure and CCL21-mediated migration. The effects are in large part due to excessive 1,25(OH)₂D₃ formation.
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Abed M, Towhid ST, Pakladok T, Alesutan I, Götz F, Gulbins E, Lang F. Effect of bacterial peptidoglycan on erythrocyte death and adhesion to endothelial cells. Int J Med Microbiol 2013; 303:182-9. [PMID: 23537625 DOI: 10.1016/j.ijmm.2013.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 01/16/2013] [Accepted: 01/27/2013] [Indexed: 11/20/2022] Open
Abstract
Peptidoglycans, bacterial wall components, have previously been shown to trigger eryptosis, the suicidal erythrocyte death, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the cell surface. Phosphatidylserine exposing erythrocytes adhere to the vascular wall at least partially by interaction of erythrocytic phosphatidylserine with endothelial CXC chemokine ligand 16 (CXCL16). The present study explored whether peptidoglycan exposure fosters the adhesion of erythrocytes to human umbilical vein endothelial cells (HUVEC). To this end, HUVEC were treated for 48 h with peptidoglycan (10 μg/ml) and CXCL16 abundance determined by confocal microscopy and FACS analysis. Moreover, human erythrocytes were exposed for 48 h to peptidoglycan (10 μg/ml) and phosphatidylserine exposure estimated from binding of fluorescent annexin-V, cell volume from forward scatter in FACS analysis and erythrocyte adhesion to human umbilical vein endothelial cells (HUVEC) from trapping of labeled erythrocytes in a flow chamber. As a result, bacterial peptidoglycan exposure was followed by increased CXCL16 expression in HUVEC as well as erythrocyte shrinkage, phosphatidylserine exposure and adhesion to HUVEC under flow conditions at arterial shear rates. The adhesion was significantly attenuated but not abrogated in the presence of either, erythrocyte phosphatidylserine-coating annexin-V (5 μl/ml) or CXCL16 neutralizing antibody directed against endothelial CXCL16 (4 μg/ml). In conclusion, exposure to peptidoglycan increases endothelial CXCL16 expression and leads to eryptosis followed by phosphatidylserine- and CXCL16-mediated adhesion of eryptotic erythrocytes to vascular endothelial cells.
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Affiliation(s)
- Majed Abed
- Department of Physiology, University of Tuebingen, Tuebingen, Germany
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Schmid E, Bhandaru M, Nurbaeva MK, Yang W, Szteyn K, Russo A, Leibrock C, Tyan L, Pearce D, Shumilina E, Lang F. SGK3 regulates Ca(2+) entry and migration of dendritic cells. Cell Physiol Biochem 2012; 30:1423-35. [PMID: 23171960 DOI: 10.1159/000343330] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2012] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND/AIMS Dendritic cells (DCs) are antigen-presenting cells linking innate and adaptive immunity. DC maturation and migration are governed by alterations of cytosolic Ca(2+) concentrations ([Ca(2+)](i)). Ca(2+) entry is in part accomplished by store-operated Ca(2+) (SOC) channels consisting of the membrane pore-forming subunit Orai and the ER Ca(2+) sensing subunit STIM. Moreover, DC functions are under powerful regulation of the phosphatidylinositol-3-kinase (PI3K) pathway, which suppresses proinflammatory cytokine production but supports DC migration. Downstream targets of PI3K include serum- and glucocorticoid-inducible kinase isoform SGK3. The present study explored, whether SGK3 participates in the regulation of [Ca(2+)](i) and Ca(2+)-dependent functions of DCs, such as maturation and migration. METHODS/RESULTS Experiments were performed with bone marrow derived DCs from gene targeted mice lacking SGK3 (sgk3(-/-)) and DCs from their wild type littermates (sgk3(+/+)). Maturation, phagocytosis and cytokine production were similar in sgk3(-/-) and sgk3(+/+) DCs. However, SOC entry triggered by intracellular Ca(2+) store depletion with the endosomal Ca(2+) ATPase inhibitor thapsigargin (1 µM) was significantly reduced in sgk3(-/-) compared to sgk3(+/+) DCs. Similarly, bacterial lipopolysaccharide (LPS, 1 µg/ml)- and chemokine CXCL12 (300 ng/ml)- induced increase in [Ca(2+)](i) was impaired in sgk3(-/-) DCs. Moreover, currents through SOC channels were reduced in sgk3(-/-) DCs. STIM2 transcript levels and protein abundance were significantly lower in sgk3(-/-) DCs than in sgk3(+/+) DCs, whereas Orai1, Orai2, STIM1 and TRPC1 transcript levels and/or protein abundance were similar in sgk3-/- and sgk3(+/+) DCs. Migration of both, immature DCs towards CXCL12 and LPS-matured DCs towards CCL21 was reduced in sgk3(-/-) as compared to sgk3(+/+) DCs. Migration of sgk3(+/+) DCs was further sensitive to SOC channel inhibitor 2-APB (50 µM) and to STIM1/STIM2 knock-down. CONCLUSION SGK3 contributes to the regulation of store-operated Ca(2+) entry into and migration of dendritic cells, effects at least partially mediated through SGK3-dependent upregulation of STIM2 expression.
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Affiliation(s)
- Evi Schmid
- Department of Physiology, University of Tübingen, Tübingen, Germany
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13
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Pasham V, Rotte A, Yang W, Zelenak C, Bhandaru M, Föller M, Lang F. OSR1-sensitive regulation of Na+/H+ exchanger activity in dendritic cells. Am J Physiol Cell Physiol 2012; 303:C416-26. [PMID: 22648948 DOI: 10.1152/ajpcell.00420.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The oxidative stress-responsive kinase 1 (OSR1) is activated by WNK (with no K kinases) and in turn stimulates the thiazide-sensitive Na-Cl cotransporter (NCC) and the furosemide-sensitive Na-K-2Cl cotransporter (NKCC), thus contributing to transport and cell volume regulation. Little is known about extrarenal functions of OSR1. The present study analyzed the impact of decreased OSR1 activity on the function of dendritic cells (DCs), antigen-presenting cells linking innate and adaptive immunity. DCs were cultured from bone marrow of heterozygous WNK-resistant OSR1 knockin mice (osr(KI)) and wild-type mice (osr(WT)). Cell volume was estimated from forward scatter in FACS analysis, ROS production from 2',7'-dichlorodihydrofluorescein-diacetate fluorescence, cytosolic pH (pH(i)) from 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein fluorescence, and Na(+)/H(+) exchanger activity from Na(+)-dependent realkalinization following ammonium pulse and migration utilizing transwell chambers. DCs expressed WNK1, WNK3, NCC, NKCC1, and OSR1. Phosphorylated NKCC1 was reduced in osr(KI) DCs. Cell volume and pH(i) were similar in osr(KI) and osr(WT) DCs, but Na(+)/H(+) exchanger activity and ROS production were higher in osr(KI) than in osr(WT) DCs. Before LPS treatment, migration was similar in osr(KI) and osr(WT) DCs. LPS (1 μg/ml), however, increased migration of osr(WT) DCs but not of osr(KI) DCs. Na(+)/H(+) exchanger 1 inhibitor cariporide (10 μM) decreased cell volume, intracellular reactive oxygen species (ROS) formation, Na(+)/H(+) exchanger activity, and pH(i) to a greater extent in osr(KI) than in osr(WT) DCs. LPS increased cell volume, Na(+)/H(+) exchanger activity, and ROS formation in osr(WT) DCs but not in osr(KI) DCs and blunted the difference between osr(KI) and osr(WT) DCs. Na(+)/H(+) exchanger activity in osr(WT) DCs was increased by the NKCC1 inhibitor furosemide (100 nM) to values similar to those in osr(KI) DCs. Oxidative stress (10 μM tert-butyl-hydroperoxide) increased Na(+)/H(+) exchanger activity in osr(WT) DCs but not in osr(KI) DCs and reversed the difference between genotypes. Cariporide virtually abrogated Na(+)/H(+) exchanger activity in both genotypes and blunted LPS-induced cell swelling and ROS formation in osr(WT) mice. In conclusion, partial OSR1 deficiency influences Na(+)/H(+) exchanger activity, ROS formation, and migration of dendritic cells.
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Nurbaeva MK, Schmid E, Szteyn K, Yang W, Viollet B, Shumilina E, Lang F. Enhanced Ca²⁺ entry and Na+/Ca²⁺ exchanger activity in dendritic cells from AMP-activated protein kinase-deficient mice. FASEB J 2012; 26:3049-58. [PMID: 22474243 DOI: 10.1096/fj.12-204024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In dendritic cells (DCs), chemotactic chemokines, such as CXCL12, rapidly increase cytosolic Ca(2+)concentrations ([Ca(2+)](i)) by triggering Ca(2+) release from intracellular stores followed by store-operated Ca(2+) (SOC) entry. Increase of [Ca(2+)](i) is blunted and terminated by Ca(2+) extrusion, accomplished by K(+)-independent Na(+)/Ca(2+) exchangers (NCXs) and K(+)-dependent Na(+)/Ca(2+) exchangers (NCKXs). Increased [Ca(2+)](i) activates energy-sensing AMP-activated protein kinase (AMPK), which suppresses proinflammatory responses of DCs and macrophages. The present study explored whether AMPK participates in the regulation of DC [Ca(2+)](i) and migration. DCs were isolated from AMPKα1-deficient (ampk(-/-)) mice and, as control, from their wild-type (ampk(+/+)) littermates. AMPKα1, Orai1-2, STIM1-2, and mitochondrial calcium uniporter protein expression was determined by Western blotting, [Ca(2+)](i) by Fura-2 fluorescence, SOC entry by inhibition of endosomal Ca(2+) ATPase with thapsigargin (1 μM), Na(+)/Ca(2+) exchanger activity from increase of [Ca(2+)](i), and respective whole-cell current in patch clamp following removal of extracellular Na(+). Migration was quantified utilizing transwell chambers. AMPKα1 protein is expressed in ampk(+/+) DCs but not in ampk(-/-) DCs. CXCL12 (300 ng/ml)-induced increase of [Ca(2+)](i), SOC entry, Orai 1 protein abundance, NCX, and NCKX were all significantly higher in ampk(-/-) DCs than in ampk(+/+) DCs. NCX and NCKX currents were similarly increased in ampk(-/-) DCs. Moreover, CXCL12 (50 ng/ml)-induced DC migration was enhanced in ampk(-/-) DCs. AMPK thus inhibits SOC entry, Na(+)/Ca(2+) exchangers, and migration of DCs.
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Calcium influx blocked by SK&F 96365 modulates the LPS plus IFN-γ-induced inflammatory response in murine peritoneal macrophages. Int Immunopharmacol 2012; 12:384-93. [DOI: 10.1016/j.intimp.2011.12.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 11/25/2011] [Accepted: 12/15/2011] [Indexed: 11/19/2022]
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16
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Yang W, Bhandaru M, Pasham V, Bobbala D, Zelenak C, Jilani K, Rotte A, Lang F. Effect of Thymoquinone on Cytosolic pH and Na +/H + Exchanger Activity in Mouse Dendritic Cells. Cell Physiol Biochem 2012; 29:21-30. [DOI: 10.1159/000337583] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2012] [Indexed: 01/13/2023] Open
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17
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Regulation of Na+/H+ exchanger in dendritic cells by Akt2. Pflugers Arch 2011; 463:355-63. [DOI: 10.1007/s00424-011-1015-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/10/2011] [Accepted: 08/11/2011] [Indexed: 12/27/2022]
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18
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Heise N, Shumilina E, Nurbaeva MK, Schmid E, Szteyn K, Yang W, Xuan NT, Wang K, Zemtsova IM, Duszenko M, Lang F. Effect of dexamethasone on Na+/Ca2+exchanger in dendritic cells. Am J Physiol Cell Physiol 2011; 300:C1306-13. [DOI: 10.1152/ajpcell.00396.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Ca+-dependent signaling regulates the function of dendritic cells (DCs), antigen-presenting cells linking innate and adaptive immunity. The activity of DCs is suppressed by glucocorticoids, potent immunosuppressive hormones. The present study explored whether the glucocorticoid dexamethasone influences the cytosolic Ca2+concentration ([Ca2+]i) in DCs. To this end, DCs were isolated from mouse bone marrow. According to fura-2 fluorescence, exposure of DCs to lipopolysaccharide (LPS, 100 ng/ml) increased [Ca2+]i, an effect significantly blunted by overnight incubation with 10 nM dexamethasone before LPS treatment. Dexamethasone did not affect the Ca2+content of intracellular stores, sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA)2 and SERCA3 expression, ryanodine receptor (RyR)1 expression, or Ca2+entry through store-operated Ca2+channels. In contrast, dexamethasone increased the transcript level and the membrane protein abundance of the Na+/Ca2+exchanger NCX3. The activity of Na+/Ca2+exchangers was assessed by removal of extracellular Na+in the presence of external Ca2+, a maneuver triggering the Ca2+influx mode. Indeed, Na+removal resulted in a rapid transient increase of [Ca2+]iand induced an outwardly directed current as measured in whole cell patch-clamp experiments. Dexamethasone significantly augmented the increase of [Ca2+]iand the outward current following removal of extracellular Na+. The NCX blocker KB-R7943 reversed the inhibitory effect of dexamethasone on LPS-induced increase in [Ca2+]i. Dexamethasone blunted LPS-induced stimulation of CD86 expression and TNF-α production, an effect significantly less pronounced in the presence of NCX blocker KB-R7943. In conclusion, our results show that glucocorticoid treatment blunts LPS-induced increase in [Ca2+]iin DCs by increasing expression and activity of Na+/Ca2+exchanger NCX3. The effect contributes to the inhibitory effect of the glucocorticoid on DC maturation.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Michael Duszenko
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
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Shumilina E, Huber SM, Lang F. Ca2+ signaling in the regulation of dendritic cell functions. Am J Physiol Cell Physiol 2011; 300:C1205-14. [PMID: 21451105 DOI: 10.1152/ajpcell.00039.2011] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Dendritic cells (DCs) are highly versatile antigen-presenting cells critically involved in both innate and adaptive immunity as well as maintenance of self-tolerance. DC function is governed by Ca(2+) signaling, which directs the DC responses to diverse antigens, including Toll-like receptor ligands, intact bacteria, and microbial toxins. Ca(2+)-sensitive DC functions include DC activation, maturation, migration, and formation of immunological synapses with T cells. Moreover, alterations of cytosolic Ca(2+) trigger immune suppression or switch off DC activity. Ca(2+) signals are generated by the orchestration of Ca(2+) transport processes across plasma, endoplasmic reticulum, and inner mitochondrial membrane. These processes include active pumping of Ca(2+), Ca(2+)/Na(+) antiport, and electrodiffusion through Ca(2+)-permeable channels or uniporters. Ca(2+) channels in the plasma membrane such as Ca(2+) release-activated Ca(2+) or L-type Ca(2+) channels are tightly regulated by the membrane potential which in turn depends on the activity of voltage-gated K(+) or Ca(2+)-activated nonselective cation channels. The rapidly growing knowledge on the function and regulation of these membrane transport proteins provides novel insight into pathophysiological mechanisms underlying dysfunction of the immune system and opens novel therapeutic opportunity to favorably influence the function of the immune system.
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Affiliation(s)
- Ekaterina Shumilina
- Department of Physiology, University of Tübingen, Gmelinstrasse 5, Tübingen, Germany.
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20
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Rotte A, Pasham V, Eichenmüller M, Yang W, Bhandaru M, Lang F. Influence of Dexamethasone on Na +/H + Exchanger Activity in Dendritic Cells. Cell Physiol Biochem 2011; 28:305-14. [DOI: 10.1159/000331746] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2011] [Indexed: 11/19/2022] Open
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Felipe A, Soler C, Comes N. Kv1.5 in the immune system: the good, the bad, or the ugly? Front Physiol 2010; 1:152. [PMID: 21423392 PMCID: PMC3059964 DOI: 10.3389/fphys.2010.00152] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 10/28/2010] [Indexed: 11/13/2022] Open
Abstract
For the last 20 years, knowledge of the physiological role of voltage-dependent potassium channels (Kv) in the immune system has grown exponentially. Leukocytes express a limited repertoire of Kv channels, which contribute to the membrane potential. These proteins are involved in the immune response and are therefore considered good pharmacological targets. Although there is a clear consensus about the physiological relevance of Kv1.3, the expression and the role of Kv1.5 are controversial. However, recent reports indicate that certain heteromeric Kv1.3/Kv1.5 associations may provide insight on Kv1.5. Here, we summarize what is known about this issue and highlight the role of Kv1.5 partnership interactions that could be responsible for this debate. The Kv1.3/Kv1.5 heterotetrameric composition of the channel and their possible differential associations with accessory regulatory proteins warrant further investigation.
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Affiliation(s)
- Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biologia Molecular, Institut de Biomedicina, Universitat de Barcelona Barcelona, Spain.
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22
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Müller-Anstett MA, Müller P, Albrecht T, Nega M, Wagener J, Gao Q, Kaesler S, Schaller M, Biedermann T, Götz F. Staphylococcal peptidoglycan co-localizes with Nod2 and TLR2 and activates innate immune response via both receptors in primary murine keratinocytes. PLoS One 2010; 5:e13153. [PMID: 20949035 PMCID: PMC2951902 DOI: 10.1371/journal.pone.0013153] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 08/24/2010] [Indexed: 01/01/2023] Open
Abstract
In mammalian host cells staphylococcal peptidoglycan (PGN) is recognized by Nod2. Whether PGN is also recognized by TLR2 is disputed. Here we carried out PGN co-localization and stimulation studies with TLR2 and Nod2 in wild type and mutant host cells. To exclude contamination with lipoproteins, polymeric staphylococcal PGN (PGN(pol)) was isolated from Staphylococcus aureus Δlgt (lacking lipidated prelipoproteins). PGN(pol) was biotinylated (PGN-Bio) for fluorescence monitoring with specific antibodies. Keratinocytes from murine oral epithelium (MK) readily internalized PGN-Bio in an endocytosis-like process. In wt MK, PGN(pol) induced intracellular accumulation of Nod2 and TLR2 and co-localized with Nod2 and TLR2, but not with TLR4. In TLR2-deficient MK Nod2 and in Nod2-deficient MK TLR2 was induced, indicating that PGN(pol) recognition by Nod2 is independent of TLR2 and vice versa. In both mutants IL-6 and IL-1B release was decreased by approximately 50% compared to wt MK, suggesting that the immune responses induced by Nod2 and TLR2 are comparable and that the two receptors act additively in MK. In TLR2-transfected HEK293 cells PGN(pol) induced NFkB-promoter fused luciferase expression. To support the data, co-localization and signaling studies were carried out with SHL-PGN, a lipase protein covalently tethered to PGN-fragments of varying sizes at its C-terminus. SHL-PGN also co-localized with Nod2 or TLR2 and induced their accumulation, while SHL without PGN did not. The results show that staphylococcal PGN not only co-localizes with Nod2 but also with TLR2. PGN is able to stimulate the immune system via both receptors.
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Affiliation(s)
| | - Patrick Müller
- Microbial Genetics, University of Tübingen, Tübingen, Germany
| | - Till Albrecht
- Microbial Genetics, University of Tübingen, Tübingen, Germany
| | - Mulugeta Nega
- Microbial Genetics, University of Tübingen, Tübingen, Germany
| | - Jeanette Wagener
- Department of Dermatology, University of Tübingen, Tübingen, Germany
| | - Qiang Gao
- Microbial Genetics, University of Tübingen, Tübingen, Germany
| | - Susanne Kaesler
- Department of Dermatology, University of Tübingen, Tübingen, Germany
| | - Martin Schaller
- Department of Dermatology, University of Tübingen, Tübingen, Germany
| | - Tilo Biedermann
- Department of Dermatology, University of Tübingen, Tübingen, Germany
| | - Friedrich Götz
- Microbial Genetics, University of Tübingen, Tübingen, Germany
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Tyan L, Sopjani M, Dërmaku-Sopjani M, Schmid E, Yang W, Xuan NT, Shumilina E, Lang F. Inhibition of voltage-gated K+ channels in dendritic cells by rapamycin. Am J Physiol Cell Physiol 2010; 299:C1379-85. [PMID: 20926775 DOI: 10.1152/ajpcell.00367.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rapamycin, an inhibitor of the serine/threonine kinase mammalian target of rapamycin (mTOR), is a widely used immunosuppressive drug. Rapamycin affects the function of dendritic cells (DCs), antigen-presenting cells participating in the initiation of primary immune responses and the establishment of immunological memory. Voltage-gated K(+) (Kv) channels are expressed in and impact on the function of DCs. The present study explored whether rapamycin influences Kv channels in DCs. To this end, DCs were isolated from murine bone marrow and ion channel activity was determined by whole cell patch clamp. To more directly analyze an effect of mTOR on Kv channel activity, Kv1.3 and Kv1.5 were expressed in Xenopus oocytes with or without the additional expression of mTOR and voltage-gated currents were determined by dual-electrode voltage clamp. As a result, preincubation with rapamycin (0-50 nM) led to a gradual decline of Kv currents in DCs, reaching statistical significance within 6 h and 50 nM of rapamycin. Rapamycin accelerated Kv channel inactivation. Coexpression of mTOR upregulated Kv1.3 and Kv1.5 currents in Xenopus oocytes. Furthermore, mTOR accelerated Kv1.3 channel activation and slowed down Kv1.3 channel inactivation. In conclusion, mTOR stimulates Kv channels, an effect contributing to the immunomodulating properties of rapamycin in DCs.
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Affiliation(s)
- Leonid Tyan
- Department of Physiology, University of Tübingen, Tübingen, Germany
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Phosphoinositide 3-kinase-dependent regulation of Na+/H+ exchanger in dendritic cells. Pflugers Arch 2010; 460:1087-96. [PMID: 20857304 DOI: 10.1007/s00424-010-0879-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/14/2010] [Accepted: 09/01/2010] [Indexed: 10/19/2022]
Abstract
Dendritic cells (DCs), antigen-presenting cells that are able to initiate primary immune responses and to establish immunological memory, are activated by exposure to bacterial lipopolysaccharides (LPS), which leads to cell swelling, triggering ROS formation and stimulating migration. The function of DCs is regulated by the phosphoinositide 3 (PI3) kinase pathway. On the other hand, PI3 kinase is an important regulator of diverse transporters including the Na(+)/H(+) exchanger (NHE). The present study was performed to elucidate the role of PI3 kinase in NHE activity, cell volume, ROS formation, and migration. To this end, DCs were isolated from murine bone marrow, cytosolic pH (pH(i)) determined utilizing 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein fluorescence, Na(+)/H(+) exchanger activity from the Na(+)-dependent realkalinization after an ammonium pulse, cell volume from forward scatter in fluorescence-activated cell sorter analysis, ROS production from 2',7'-dichlorodihydrofluorescein diacetate fluorescence, and migration utilizing transwell migration assays. Exposure of DCs to LPS led within 4 h to a gradual cytosolic acidification paralleled by a transient time- and dose-dependent increase of Na(+)/H(+) exchanger activity, cell swelling, enhanced ROS production, and stimulation of migration. The PI3K inhibitors Wortmannin (1 μM) or LY294002 (10 μM) significantly blunted the effects of LPS on NHE activity, cell volume, ROS production, and migration. The present observations disclose a critical role of PI3K signaling in the regulation of DC function following exposure to LPS.
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