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Cao Z, Yang X, Yang W, Chen F, Jiang W, Zhan S, Jiang F, Li J, Ye C, Lang L, Zhang S, Feng Z, Lai X, Liu Y, Mao L, Cai H, Teng Y, Xie J. Modulation of Dendritic Cell Function via Nanoparticle-Induced Cytosolic Calcium Changes. ACS NANO 2024; 18:7618-7632. [PMID: 38422984 PMCID: PMC10938921 DOI: 10.1021/acsnano.4c00550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 02/15/2024] [Accepted: 02/22/2024] [Indexed: 03/02/2024]
Abstract
Calcium nanoparticles have been investigated for applications, such as drug and gene delivery. Additionally, Ca2+ serves as a crucial second messenger in the activation of immune cells. However, few studies have systematically studied the effects of calcium nanoparticles on the calcium levels and functions within immune cells. In this study, we explore the potential of calcium nanoparticles as a vehicle to deliver calcium into the cytosol of dendritic cells (DCs) and influence their functions. We synthesized calcium hydroxide nanoparticles, coated them with a layer of silica to prevent rapid degradation, and further conjugated them with anti-CD205 antibodies to achieve targeted delivery to DCs. Our results indicate that these nanoparticles can efficiently enter DCs and release calcium ions in a controlled manner. This elevation in cytosolic calcium activates both the NFAT and NF-κB pathways, in turn promoting the expression of costimulatory molecules, antigen-presenting molecules, and pro-inflammatory cytokines. In mouse tumor models, the calcium nanoparticles enhanced the antitumor immune response and augmented the efficacy of both radiotherapy and chemotherapy without introducing additional toxicity. Our study introduces a safe nanoparticle immunomodulator with potential widespread applications in cancer therapy.
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Affiliation(s)
- Zhengwei Cao
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Xueyuan Yang
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Wei Yang
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Fanghui Chen
- Department
of Hematology and Medical Oncology & Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Wen Jiang
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Shuyue Zhan
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Fangchao Jiang
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Jianwen Li
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Chenming Ye
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Liwei Lang
- Department
of Physiology, Medical College of Georgia, Augusta University, Augusta, Georgia 30907, United States
| | - Sirui Zhang
- Institute
of Bioinformatics, University of Georgia, Athens, Georgia 30602, United States
| | - Zhizi Feng
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Xinning Lai
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Yang Liu
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Leidong Mao
- School
of
Electrical and Computer Engineering, College of Engineering, University of Georgia, Athens, Georgia 30602, United States
| | - Houjian Cai
- Department
of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, Georgia 30602, United States
| | - Yong Teng
- Department
of Hematology and Medical Oncology & Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia 30322, United States
| | - Jin Xie
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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2
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Shi J, Ma Q, Su W, Liu C, Zhang H, Liu Y, Li X, Jiang X, Ge C, Kong F, Chen Y, Qu D. Effervescent cannabidiol solid dispersion-doped dissolving microneedles for boosted melanoma therapy via the "TRPV1-NFATc1-ATF3" pathway and tumor microenvironment engineering. Biomater Res 2023; 27:48. [PMID: 37198657 DOI: 10.1186/s40824-023-00390-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 05/07/2023] [Indexed: 05/19/2023] Open
Abstract
BACKGROUND Conventional dissolving microneedles (DMNs) face significant challenges in anti-melanoma therapy due to the lack of active thrust to achieve efficient transdermal drug delivery and intra-tumoral penetration. METHODS In this study, the effervescent cannabidiol solid dispersion-doped dissolving microneedles (Ef/CBD-SD@DMNs) composed of the combined effervescent components (CaCO3 & NaHCO3) and CBD-based solid dispersion (CBD-SD) were facilely fabricated by the "one-step micro-molding" method for boosted transdermal and tumoral delivery of cannabidiol (CBD). RESULTS Upon pressing into the skin, Ef/CBD-SD@DMNs rapidly produce CO2 bubbles through proton elimination, significantly enhancing the skin permeation and tumoral penetration of CBD. Once reaching the tumors, Ef/CBD-SD@DMNs can activate transient receptor potential vanilloid 1 (TRPV1) to increase Ca2+ influx and inhibit the downstream NFATc1-ATF3 signal to induce cell apoptosis. Additionally, Ef/CBD-SD@DMNs raise intra-tumoral pH environment to trigger the engineering of the tumor microenvironment (TME), including the M1 polarization of tumor-associated macrophages (TAMs) and increase of T cells infiltration. The introduction of Ca2+ can not only amplify the effervescent effect but also provide sufficient Ca2+ with CBD to potentiate the anti-melanoma efficacy. Such a "one stone, two birds" strategy combines the advantages of effervescent effects on transdermal delivery and TME regulation, creating favorable therapeutic conditions for CBD to obtain stronger inhibition of melanoma growth in vitro and in vivo. CONCLUSIONS This study holds promising potential in the transdermal delivery of CBD for melanoma therapy and offers a facile tool for transdermal therapies of skin tumors.
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Affiliation(s)
- Jiachen Shi
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
| | - Qiuling Ma
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
| | - Wenting Su
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
| | - Congyan Liu
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
- Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, China
| | - Huangqin Zhang
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
- Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, China
| | - Yuping Liu
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
- Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, China
| | - Xiaoqi Li
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
- Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, China
| | - Xi Jiang
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
| | - Chang Ge
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
| | - Fei Kong
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
| | - Yan Chen
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China
- Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, China
| | - Ding Qu
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China.
- Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, China.
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3
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Zhu C, Shi Y, You J. Immune Cell Connection by Tunneling Nanotubes: The Impact of Intercellular Cross-Talk on the Immune Response and Its Therapeutic Applications. Mol Pharm 2021; 18:772-786. [PMID: 33529022 DOI: 10.1021/acs.molpharmaceut.0c01248] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Direct intercellular communication is an important prerequisite for the development of multicellular organisms, the regeneration of tissue, and the maintenance of various physiological activities. Tunnel nanotubes (TNTs), which have diameters of approximately 50-1500 nm and lengths of up to several cell diameters, can connect cells over long distances and have emerged as one of the most important recently discovered types of efficient communication between cells. Moreover, TNTs can also directly transfer organelles, vehicles, proteins, genetic material, ions, and small molecules from one cell to adjacent and even distant cells. However, the mechanism of intercellular communication between various immune cells within the complex immune system has not been fully elucidated. Studies in the past decades have confirmed the existence of TNTs in many types of cells, especially in various kinds of immune cells. TNTs display different structural and functional characteristics between and within different immunocytes, playing a major role in the transmission of signals across various kinds of immune cells. In this review, we introduce the discovery and structure of TNTs, as well as their different functional properties within different immune cells. We also discuss the roles of TNTs in potentiating the immune response and their potential therapeutic applications.
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Affiliation(s)
- Chunqi Zhu
- College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Yingying Shi
- College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, People's Republic of China
| | - Jian You
- College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang 310058, People's Republic of China
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4
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Stimulation of ORAI1 expression, store-operated Ca 2+ entry, and osteogenic signaling by high glucose exposure of human aortic smooth muscle cells. Pflugers Arch 2020; 472:1093-1102. [PMID: 32556706 DOI: 10.1007/s00424-020-02405-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 04/24/2020] [Accepted: 05/22/2020] [Indexed: 12/23/2022]
Abstract
Diabetes and chronic kidney disease (CKD) both trigger vascular osteogenic signaling and calcification leading to early death by cardiovascular events. Osteogenic signaling involves upregulation of the transcription factors CBFA1, MSX2, and SOX9, as well as alkaline phosphatase (ALP), an enzyme fostering calcification by degrading the calcification inhibitor pyrophosphate. In CKD, osteogenic signaling is triggered by hyperphosphatemia, which upregulates the serum and glucocorticoid-inducible kinase SGK1, a strong stimulator of the Ca2+-channel ORAI1. The channel is activated by STIM1 and accomplishes store-operated Ca2+-entry (SOCE). The present study explored whether exposure of human aortic smooth muscle cells (HAoSMCs) to high extracellular glucose concentrations similarly upregulates ORAI1 and/or STIM1 expression, SOCE, and osteogenic signaling. To this end, HAoSMCs were exposed to high extracellular glucose concentrations (15 mM, 24 h) without or with additional exposure to the phosphate donor ß-glycerophosphate. Transcript levels were estimated using qRT-PCR, protein abundance using Western blotting, ALP activity using a colorimetric assay kit, calcium deposits utilizing Alizarin red staining, cytosolic Ca2+-concentration ([Ca2+]i) by Fura-2-fluorescence, and SOCE from increase of [Ca2+]i following re-addition of extracellular Ca2+ after store depletion with thapsigargin (1 μM). As a result, glucose enhanced the transcript levels of SGK1 and ORAI1, ORAI2, and STIM2, protein abundance of ORAI1, SOCE, the transcript levels of CBFA1, MSX2, SOX9, and ALPL, as well as calcium deposits. Moreover, glucose significantly augmented the stimulating effect of ß-glycerophosphate on transcript levels of SGK1 and ORAI1, SOCE, the transcript levels of osteogenic markers, as well as calcium deposits. ORAI1 inhibitor MRS1845 (10 μM) significantly blunted the glucose-induced upregulation of the CBFA1 and MSX2 transcript levels. In conclusion, the hyperglycemia of diabetes stimulates expression of SGK1 and ORAI1, thus, augmenting store-operated Ca2+-entry and osteogenic signaling in HAoSMCs.
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5
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Pelzl L, Sahu I, Ma K, Heinzmann D, Bhuyan AAM, Al-Maghout T, Sukkar B, Sharma Y, Marini I, Rigoni F, Artunc F, Cao H, Gutti R, Voelkl J, Pieske B, Gawaz M, Bakchoul T, Lang F. Beta-Glycerophosphate-Induced ORAI1 Expression and Store Operated Ca 2+ Entry in Megakaryocytes. Sci Rep 2020; 10:1728. [PMID: 32015442 PMCID: PMC6997179 DOI: 10.1038/s41598-020-58384-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 01/03/2020] [Indexed: 12/13/2022] Open
Abstract
Impairment of renal phosphate elimination in chronic kidney disease (CKD) leads to enhanced plasma and tissue phosphate concentration, which in turn up-regulates transcription factor NFAT5 and serum & glucocorticoid-inducible kinase SGK1. The kinase upregulates ORAI1, a Ca2+-channel accomplishing store-operated Ca2+-entry (SOCE). ORAI1 is stimulated following intracellular store depletion by Ca2+-sensors STIM1 and/or STIM2. In megakaryocytes and blood platelets SOCE and thus ORAI1 are powerful regulators of activity. The present study explored whether the phosphate-donor ß-glycerophosphate augments NFAT5, ORAI1,2,3 and/or STIM1,2 expressions and thus SOCE in megakaryocytes. Human megakaryocytic Meg01cells were exposed to 2 mM of phosphate-donor ß-glycerophosphate for 24 hours. Platelets were isolated from blood samples of patients with impaired kidney function or control volunteers. Transcript levels were estimated utilizing q-RT-PCR, cytosolic Ca2+-concentration ([Ca2+]i) by Fura-2-fluorescence, and SOCE from increase of [Ca2+]i following re-addition of extracellular Ca2+ after store depletion with thapsigargin (1 µM). NFAT5 and ORAI1 protein abundance was estimated with Western blots. As a result, ß-glycerophosphate increased NFAT5, ORAI1/2/3, STIM1/2 transcript levels, as well as SOCE. Transcript levels of NFAT5, SGK1, ORAI1/2/3, and STIM1/2 as well as NFAT5 and ORAI1 protein abundance were significantly higher in platelets isolated from patients with impaired kidney function than in platelets from control volunteers. In conclusion, phosphate-donor ß-glycerophosphate triggers a signaling cascade of NFAT5/SGK1/ORAI/STIM, thus up-regulating store-operated Ca2+-entry.
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Affiliation(s)
- Lisann Pelzl
- Transfusion Medicine, Medical Faculty, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | - Itishri Sahu
- Department of Internal Medicine III, Eberhard Karl University Tuebingen, Tuebingen, Germany.,Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Ke Ma
- Department of Internal Medicine III, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | - David Heinzmann
- Department of Internal Medicine III, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | | | - Tamer Al-Maghout
- Department of Internal Medicine III, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | - Basma Sukkar
- Department of Internal Medicine III, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | - Yamini Sharma
- Department of Internal Medicine III, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | - Irene Marini
- Transfusion Medicine, Medical Faculty, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | - Flaviana Rigoni
- Transfusion Medicine, Medical Faculty, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | - Ferruh Artunc
- Department of Internal Medicine IV, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | - Hang Cao
- Department of Internal Medicine III, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | - Ravi Gutti
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, 500046, India
| | - Jakob Voelkl
- Institute for Physiology, Johannes Kepler University, Linz, Austria.,DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany.,Department of Nephrology and Medical Intensive Care, Charité University Medicine, Berlin, Germany.,Department of Internal Medicine and Cardiology, Campus Virchow Klinikum, Charité University Medicine, Berlin, Germany
| | - Burkert Pieske
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, and Department of Internal Medicine and Cardiology, German Heart Center Berlin (DHZB), Berlin, Germany.,Department of Internal Medicine and Cardiology, Campus Virchow Klinikum, Charité University Medicine, Berlin, Germany
| | - Meinrad Gawaz
- Department of Internal Medicine III, Eberhard Karl University Tuebingen, Tuebingen, Germany
| | - Tamam Bakchoul
- Transfusion Medicine, Medical Faculty, Eberhard Karl University Tuebingen, Tuebingen, Germany.,Centre for Clinical Transfusion Medicine, University Hospital of Tuebingen, Tuebingen, Germany
| | - Florian Lang
- Department of Vegetative and Clinical Physiology, Eberhard Karl University Tuebingen, Tuebingen, Germany.
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6
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Zhu X, Ma K, Zhou K, Voelkl J, Alesutan I, Leibrock C, Nürnberg B, Lang F. Reversal of phosphate-induced ORAI1 expression, store-operated Ca 2+ entry and osteogenic signaling by MgCl 2 in human aortic smooth muscle cells. Biochem Biophys Res Commun 2019; 523:18-24. [PMID: 31831178 DOI: 10.1016/j.bbrc.2019.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 11/01/2019] [Indexed: 02/07/2023]
Abstract
In chronic kidney disease, renal phosphate retention leads to hyperphosphatemia with subsequent vascular osteogenic signaling and calcification. Osteogenic signaling involves up-regulation of the transcription factors CBFA1, MSX2, and SOX9, as well as alkaline phosphatase (ALP), an enzyme stimulating calcification by degrading the calcification inhibitor pyrophosphate. Stimulation of osteogenic signaling and calcification by phosphate donor β-glycerophosphate in human aortic smooth muscle cells (HAoSMCs) is attenuated by MgCl2, an effect mimicked by Ca2+-sensing receptor agonist GdCl3. Most recent observations revealed that the effect of β-glycerophosphate on osteogenic signaling requires ORAI1, a Ca2+-channel accomplishing store-operated Ca2+-entry (SOCE), which is stimulated by Ca2+-sensor STIM1. The present study explored whether ORAI1 and/or STIM1 expression and, thus, SOCE and osteogenic signaling in HAoSMCs are sensitive to MgCl2 and/or GdCl3. To this end, transcript levels were estimated using q-RT-PCR, protein abundance with western blotting, cytosolic Ca2+-concentration ([Ca2+]i) by Fura-2-fluorescence, and SOCE from increase of [Ca2+]i following re-addition of extracellular Ca2+ after store depletion with thapsigargin (1 μM). As a result, 24 h exposure to β-glycerophosphate (2 mM) significantly enhanced transcript levels of ORAI1 and STIM1 as well as SOCE, effects significantly blunted or virtually abrogated by 1.5 mM MgCl2 and by 50 μM GdCl3. In conclusion, MgCl2 and GdCl3 are powerful inhibitors of ORAI1 and STIM1 expression and store-operated Ca2+-entry, effects affecting osteogenic signalling in vascular smooth muscle cells.
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Affiliation(s)
- Xuexue Zhu
- Department of Pharmacology, Experimental Therapy & Toxicology, Eberhard-Karls-University of Tübingen, Germany
| | - Ke Ma
- Department of Pharmacology, Experimental Therapy & Toxicology, Eberhard-Karls-University of Tübingen, Germany
| | - Kuo Zhou
- Department of Pharmacology, Experimental Therapy & Toxicology, Eberhard-Karls-University of Tübingen, Germany
| | - Jakob Voelkl
- Institute for Physiology, Johannes-Kepler-University Linz, Austria
| | - Ioana Alesutan
- Institute for Physiology, Johannes-Kepler-University Linz, Austria
| | | | - Bernd Nürnberg
- Department of Pharmacology, Experimental Therapy & Toxicology, Eberhard-Karls-University of Tübingen, Germany
| | - Florian Lang
- Department of Physiology, Eberhard-Karls-University, Tübingen, Germany.
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7
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Ma K, Liu P, Al-Maghout T, Sukkar B, Cao H, Voelkl J, Alesutan I, Pieske B, Lang F. Phosphate-induced ORAI1 expression and store-operated Ca 2+ entry in aortic smooth muscle cells. J Mol Med (Berl) 2019; 97:1465-1475. [PMID: 31385016 DOI: 10.1007/s00109-019-01824-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 07/02/2019] [Accepted: 07/25/2019] [Indexed: 12/16/2022]
Abstract
Compromised renal phosphate elimination in chronic kidney disease (CKD) leads to hyperphosphatemia, which in turn triggers osteo-/chondrogenic signaling in vascular smooth muscle cells (VSMCs) and vascular calcification. Osteo-/chondrogenic transdifferentiation of VSMCs leads to upregulation of the transcription factors MSX2, CBFA1, and SOX9 as well as tissue-nonspecific alkaline phosphatase (ALPL) which fosters calcification by degrading the calcification inhibitor pyrophosphate. Osteo-/chondrogenic signaling in VSMCs involves the serum- and glucocorticoid-inducible kinase SGK1. As shown in other cell types, SGK1 is a powerful stimulator of ORAI1, a Ca2+-channel accomplishing store-operated Ca2+-entry (SOCE). ORAI1 is stimulated following intracellular store depletion by the Ca2+ sensor STIM1. The present study explored whether phosphate regulates ORAI1 and/or STIM1 expression and, thus, SOCE in VSMCs. To this end, primary human aortic smooth muscle cells (HAoSMCs) were exposed to the phosphate donor β-glycerophosphate. Transcript levels were estimated by qRT-PCR, protein abundance by western blotting, ALPL activity by colorimetry, calcification by alizarin red S staining, cytosolic Ca2+-concentration ([Ca2+]i) by Fura-2-fluorescence, and SOCE from increase of [Ca2+]i following re-addition of extracellular Ca2+ after store depletion with thapsigargin. As a result, β-glycerophosphate treatment increased ORAI1 and STIM1 transcript levels and protein abundance as well as SOCE in HAoSMCs. Additional treatment with ORAI1 inhibitor MRS1845 or SGK1 inhibitor GSK650394 virtually disrupted the effects of β-glycerophosphate on SOCE. Moreover, the β-glycerophosphate-induced MSX2, CBFA1, SOX9, and ALPL mRNA expression and activity in HAoSMCs were suppressed in the presence of the ORAI1 inhibitor and upon ORAI1 silencing. In conclusion, enhanced phosphate upregulates ORAI1 and STIM1 expression and store-operated Ca2+-entry, which participate in the orchestration of osteo-/chondrogenic signaling of VSMCs. KEY MESSAGES: • In aortic SMC, phosphate donor ß-glycerophosphate upregulates Ca2+ channel ORAI1. • In aortic SMC, ß-glycerophosphate upregulates ORAI1-activator STIM1. • In aortic SMC, ß-glycerophosphate upregulates store-operated Ca2+-entry (SOCE). • The effect of ß-glycerophosphate on SOCE is disrupted by ORAI1 inhibitor MRS1845. • Stimulation of osteogenic signaling is disrupted by MRS1845 and ORAI1 silencing.
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Affiliation(s)
- Ke Ma
- Department of Pharmacology & Experimental Therapy, University of Tübingen, 72076, Tübingen, Germany
| | - Ping Liu
- Department of Pharmacology & Experimental Therapy, University of Tübingen, 72076, Tübingen, Germany
| | - Tamer Al-Maghout
- Department of Pharmacology & Experimental Therapy, University of Tübingen, 72076, Tübingen, Germany
| | - Basma Sukkar
- Department of Pharmacology & Experimental Therapy, University of Tübingen, 72076, Tübingen, Germany
| | - Hang Cao
- Department of Pharmacology & Experimental Therapy, University of Tübingen, 72076, Tübingen, Germany
| | - Jakob Voelkl
- Institute for Physiology and Pathophysiology, Johannes Kepler University Linz, 4040, Linz, Austria.,Department of Internal Medicine and Cardiology, Charité University Medicine, Campus Virchow-Klinikum, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site, Berlin, Germany.,Department of Nephrology and Medical Intensive Care, Charité University Medicine, Berlin, Germany
| | - Ioana Alesutan
- Institute for Physiology and Pathophysiology, Johannes Kepler University Linz, 4040, Linz, Austria.,Department of Internal Medicine and Cardiology, Charité University Medicine, Campus Virchow-Klinikum, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany
| | - Burkert Pieske
- Department of Internal Medicine and Cardiology, Charité University Medicine, Campus Virchow-Klinikum, Berlin, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site, Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany.,Department of Internal Medicine and Cardiology, German Heart Center Berlin (DHZB), Berlin, Germany
| | - Florian Lang
- Department of Vegetative and Clinical Physiology, University of Tübingen, Wilhelmstr. 56, 72074, Tübingen, Germany.
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8
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Abdelazeem KNM, Droppova B, Sukkar B, Al-Maghout T, Pelzl L, Zacharopoulou N, Ali Hassan NH, Abdel-Fattah KI, Stournaras C, Lang F. Upregulation of Orai1 and STIM1 expression as well as store-operated Ca 2+ entry in ovary carcinoma cells by placental growth factor. Biochem Biophys Res Commun 2019; 512:467-472. [PMID: 30902388 DOI: 10.1016/j.bbrc.2019.03.025] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 03/05/2019] [Indexed: 12/15/2022]
Abstract
Placental growth factor (PlGF) is produced by tumor cells and stimulates tumor growth and metastasis in part by upregulation of hypoxia inducible factor HIF1α. Orchestration of tumor cell proliferation and migration involves oscillations of cytosolic Ca2+ activity ([Ca2+]i). The [Ca2+]i oscillations could be accomplished by triggering of intracellular Ca2+ release followed by store-operated Ca2+-entry (SOCE). Mechanisms accomplishing SOCE include the pore-forming ion channel unit Orai1 and its regulator STIM1. The present study explored whether PlGF influences the expression of Orai1 and STIM1, as well as SOCE and whether this effect impacts on HIF1α expression. To this end, ovary carcinoma cells were cultured for 24 h without and with PlGF (10 ng/ml). Orai1, STIM1 and HIF1α transcript levels were quantified utilizing RT-PCR and Orai1, STIM1 and HIF1α protein levels by Western blotting. [Ca2+]i was estimated from Fura-2-fluorescence and SOCE from increase of [Ca2+]i following Ca2+ re-addition after Ca2+-store depletion with extracellular Ca2+ removal and sarcoendoplasmatic Ca2+-ATPase (SERCA) inhibitor thapsigargin (1 μM). As a result, exposure of ovary carcinoma cells to PlGF was followed by a significant increase of Orai1 as well as STIM1 transcript and protein levels. PlGF significantly increased store-operated Ca2+-entry following re-addition of extracellular Ca2+, an effect virtually abrogated by Orai1 inhibitor MRS1845 (10 μM). PlGF further increased HIF1α transcript and protein levels, an effect again significantly blunted by MRS1845 (10 μM). In conclusion, PlGF upregulates expression of both, Orai1 and STIM1 thus enhancing store-operated Ca2+-entry with subsequent upregulation of HIF1α.
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Affiliation(s)
- Khalid N M Abdelazeem
- Department of Internal Medicine III, Eberhard Karls,University, Tübingen, Germany; Radiation Biology Research Department, National Center for Radiation Research and Technology, Atomic Energy Authority, Cairo, Egypt
| | - Barbora Droppova
- Department of Internal Medicine III, Eberhard Karls,University, Tübingen, Germany
| | - Basma Sukkar
- Department of Internal Medicine III, Eberhard Karls,University, Tübingen, Germany
| | - Tamer Al-Maghout
- Department of Internal Medicine III, Eberhard Karls,University, Tübingen, Germany
| | - Lisann Pelzl
- Department of Internal Medicine III, Eberhard Karls,University, Tübingen, Germany
| | - Nefeli Zacharopoulou
- Department of Biochemistry, University of Crete Medical School, Heraklion, Greece
| | | | - Kamal I Abdel-Fattah
- Radiation Biology Research Department, National Center for Radiation Research and Technology, Atomic Energy Authority, Cairo, Egypt
| | - Christos Stournaras
- Department of Biochemistry, University of Crete Medical School, Heraklion, Greece
| | - Florian Lang
- Department of Internal Medicine III, Eberhard Karls,University, Tübingen, Germany.
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9
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Lang F, Pelzl L, Hauser S, Hermann A, Stournaras C, Schöls L. To die or not to die SGK1-sensitive ORAI/STIM in cell survival. Cell Calcium 2018; 74:29-34. [PMID: 29807219 DOI: 10.1016/j.ceca.2018.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 05/02/2018] [Accepted: 05/02/2018] [Indexed: 12/31/2022]
Abstract
The pore forming Ca2+ release activated Ca2+ channel (CRAC) isoforms ORAI1-3 and their regulators STIM1,2 accomplish store operated Ca2+ entry (SOCE). Activation of SOCE may lead to cytosolic Ca2+ oscillations, which in turn support cell proliferation and cell survival. ORAI/STIM and thus SOCE are upregulated by the serum and glucocorticoid inducible kinase SGK1, a kinase under powerful genomic regulation and activated by phosphorylation via the phosphoinositol-3-phosphate pathway. SGK1 enhances ORAI1 abundance partially by phosphorylation of Nedd4-2, an ubiquitin ligase priming the channel protein for degradation. The SGK1-phosphorylated Nedd4-2 binds to the protein 14-3-3 and is thus unable to ubiquinate ORAI1. SGK1 further increases the ORAI1 and STIM1 protein abundance by activating nuclear factor kappa B (NF-κB), a transcription factor upregulating the expression of STIM1 and ORAI1. SGK1-sensitive upregulation of ORAI/STIM and thus SOCE is triggered by a wide variety of hormones and growth factors, as well as several cell stressors including ischemia, radiation, and cell shrinkage. SGK1 dependent upregulation of ORAI/STIM confers survival of tumor cells and thus impacts on growth and therapy resistance of cancer. On the other hand, SGK1-dependent upregulation of ORAI1 and STIM1 may support survival of neurons and impairment of SGK1-dependent ORAI/STIM activity may foster neurodegeneration. Clearly, further experimental effort is needed to define the mechanisms linking SGK1-dependent upregulation of ORAI1 and STIM1 to cell survival and to define the impact of SGK1-dependent upregulation of ORAI1 and STIM1 on malignancy and neurodegenerative disease.
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Affiliation(s)
- Florian Lang
- Department of Vegetative Physiology, Eberhad Karls University, Wilhelmstr. 56, D-72074 Tübingen, Germany.
| | - Lisann Pelzl
- Department of Vegetative Physiology, Eberhad Karls University, Wilhelmstr. 56, D-72074 Tübingen, Germany
| | - Stefan Hauser
- German Center for Neurodegenerative Diseases, Research Site Tübingen, Germany; Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
| | - Andreas Hermann
- Department of Neurology and Center for Regenerative Therapies Dresden (CRTD), Technische Universität Dresden, Germany & DZNE, German Center for Neurodegenerative Diseases, Research Site Dresden, Germany
| | - Christos Stournaras
- Department of Biochemistry, University of Crete Medical School, Heraklion, Greece
| | - Ludger Schöls
- German Center for Neurodegenerative Diseases, Research Site Tübingen, Germany; Department of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
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Zhu XM, Dong N, Wang YB, Zhang QH, Yu Y, Yao YM, Liang HP. The involvement of endoplasmic reticulum stress response in immune dysfunction of dendritic cells after severe thermal injury in mice. Oncotarget 2018; 8:9035-9052. [PMID: 28118617 PMCID: PMC5354713 DOI: 10.18632/oncotarget.14764] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 01/10/2017] [Indexed: 12/31/2022] Open
Abstract
Suppressed adaptive immune function is one of the major concerns responsible for the development of opportunistic infections and subsequent sepsis with high mortality in severe burns. Endoplasmic reticulum stress (ERS) is the endogenous self-protective mechanism, and it plays an important role in almost every process of living by regulating the balance between homeostasis and apoptosis. The current study investigated the involvement of ERS in the pathogenesis of dysfunction of dendritic cells (DCs) in burn mice. Our results show a significant ERS response in splenic DC after burn injury. Treatment with salubrinal (Sal, reported to protect cells against ERS-induced apoptosis.) decrease the apoptotic rate of DC induced by burns, and promote maturation and activation of DC, as well as the ability to promote T cell proliferation and polarization towards Th1 immunity (all P<0.05). Gene silence of XBP-1 (key molecular in ERS response) results in the increased apoptosis and suppressed phenotypical maturation of splenic DC in burn mice. These results show that the excessive ERS is essential for immunosuppression during severe thermal injury. XBP-1 plays a pivotal role in DC functional immunomodulation in burn mice. Inhibition of apoptotic ERS response benefits mice from major burns.
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Affiliation(s)
- Xiao-Mei Zhu
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing, China.,Department of Microbiology and Immunology, Trauma Research Center, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing, China
| | - Ning Dong
- Department of Microbiology and Immunology, Trauma Research Center, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing, China
| | - Yan-Bo Wang
- Department of Microbiology and Immunology, Trauma Research Center, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing, China
| | - Qing-Hong Zhang
- Department of Microbiology and Immunology, Trauma Research Center, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing, China
| | - Yan Yu
- Department of Microbiology and Immunology, Trauma Research Center, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing, China
| | - Yong-Ming Yao
- Department of Microbiology and Immunology, Trauma Research Center, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing, China
| | - Hua-Ping Liang
- State Key Laboratory of Trauma, Burns and Combined Injury, Research Institute of Surgery, Daping Hospital, The Third Military Medical University, Chongqing, China
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11
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Sarcoplasmic reticulum Ca(2+) ATPase 2 (SERCA2) reduces the migratory capacity of CCL21-treated monocyte-derived dendritic cells. Exp Mol Med 2016; 48:e253. [PMID: 27538371 PMCID: PMC5007641 DOI: 10.1038/emm.2016.69] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 02/15/2016] [Accepted: 02/29/2016] [Indexed: 12/28/2022] Open
Abstract
The migration of dendritic cells (DCs) to secondary lymphoid organs depends on chemoattraction through the interaction of the chemokine receptors with chemokines. However, the mechanism of how lymphoid chemokines attract DCs to lymphoid organs remains unclear. Here, we demonstrate the mechanism of DC migration in response to the lymphoid chemokine CCL21. CCL21-mediated DC migration is controlled by the regulation of sarcoplasmic reticulum Ca2+ ATPase 2 (SERCA2) expression rather than through the activation of mitogen-activated protein kinases CCL21-exposed mature DCs (mDCs) exhibited decreased SERCA2 expression but not decreased phospholamban (PLB) or Hax-1 expression, which are known to be SERCA2-interacting proteins. In addition, CCL21 did not affect the mRNA levels of SERCA2 or its interacting protein Hax-1. Interestingly, SERCA2 expression was inversely related to DC migration in response to chemokine stimulation. The migratory capacity of CCL21-treated mDCs was decreased by the phospholipase C inhibitor U73122 and by the protein kinase C inhibitor BAPTA-AM. The migratory capacities of mDCs were increased in response to SERCA2 siRNA expression but were decreased by SERCA2 overexpression. In addition, DCs treated with a SERCA2-specific inhibitor (cyclopiazonic acid) had significantly increased migratory capacities as mDCs regardless of SERCA2 expression. Moreover, SERCA2 expression was dependent on DC maturation induced by cytokines or Toll-like receptor agonists. Therefore, the migratory capacities differed in differentially matured DCs. Taken together, these results suggest that SERCA2 contributes to the migration of CCL21-activated DCs as an important feature of the adaptive immune response and provide novel insights regarding the role of SERCA2 in DC functions.
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12
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Schmidt S, Liu G, Liu G, Yang W, Honisch S, Pantelakos S, Stournaras C, Hönig A, Lang F. Enhanced Orai1 and STIM1 expression as well as store operated Ca2+ entry in therapy resistant ovary carcinoma cells. Oncotarget 2015; 5:4799-810. [PMID: 25015419 PMCID: PMC4148100 DOI: 10.18632/oncotarget.2035] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mechanisms underlying therapy resistance of tumor cells include protein kinase Akt. Putative Akt targets include store-operated Ca2+-entry (SOCE) accomplished by pore forming ion channel unit Orai1 and its regulator STIM1. We explored whether therapy resistant (A2780cis) differ from therapy sensitive (A2780) ovary carcinoma cells in Akt, Orai1, and STIM1 expression, Ca2+-signaling and cell survival following cisplatin (100μM) treatment. Transcript levels were quantified with RT-PCR, protein abundance with Western blotting, cytosolic Ca2+-activity ([Ca2+]i) with Fura-2-fluorescence, SOCE from increase of [Ca2+]i following Ca2+-readdition after Ca2+-store depletion, and apoptosis utilizing flow cytometry. Transcript levels of Orai1 and STIM1, protein expression of Orai1, STIM1, and phosphorylated Akt, as well as SOCE were significantly higher in A2780cis than A2780 cells. SOCE was decreased by Akt inhibitor III (SH-6, 10μM) in A2780cis but not A2780 cells and decreased in both cell lines by Orai1 inhibitor 2-aminoethoxydiphenyl borate (2-ABP, 50μM). Phosphatidylserine exposure and late apoptosis following cisplatin treatment were significantly lower in A2780cis than A2780 cells, a difference virtually abolished by SH-6 or 2-ABP. In conclusion, Orai1/STIM1 expression and function are increased in therapy resistant ovary carcinoma cells, a property at least in part due to enhanced Akt activity and contributing to therapy resistance in those cells.
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Affiliation(s)
- Sebastian Schmidt
- Department of Physiology, University of Tübingen, D72076 Tübingen, Germany
| | | | | | | | | | | | | | | | - Florian Lang
- Department of Physiology, University of Tübingen, D72076 Tübingen, Germany
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13
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Burnstock G, Boeynaems JM. Purinergic signalling and immune cells. Purinergic Signal 2014; 10:529-64. [PMID: 25352330 PMCID: PMC4272370 DOI: 10.1007/s11302-014-9427-2] [Citation(s) in RCA: 218] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 09/12/2013] [Indexed: 11/28/2022] Open
Abstract
This review article provides a historical perspective on the role of purinergic signalling in the regulation of various subsets of immune cells from early discoveries to current understanding. It is now recognised that adenosine 5'-triphosphate (ATP) and other nucleotides are released from cells following stress or injury. They can act on virtually all subsets of immune cells through a spectrum of P2X ligand-gated ion channels and G protein-coupled P2Y receptors. Furthermore, ATP is rapidly degraded into adenosine by ectonucleotidases such as CD39 and CD73, and adenosine exerts additional regulatory effects through its own receptors. The resulting effect ranges from stimulation to tolerance depending on the amount and time courses of nucleotides released, and the balance between ATP and adenosine. This review identifies the various receptors involved in the different subsets of immune cells and their effects on the function of these cells.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Rowland Hill Street, London, NW3 2PF, UK,
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14
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Gröbner S, Lukowski R, Autenrieth IB, Ruth P. Lipopolysaccharide induces cell volume increase and migration of dendritic cells. Microbiol Immunol 2014; 58:61-7. [DOI: 10.1111/1348-0421.12116] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 11/03/2013] [Accepted: 11/13/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Sabine Gröbner
- Interfaculty Institute of Microbiology and Infection Medicine; University of Tübingen; Tübingen Germany
| | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical Pharmacy; Institute of Pharmacy, University of Tübingen; Tübingen Germany
| | - Ingo B. Autenrieth
- Interfaculty Institute of Microbiology and Infection Medicine; University of Tübingen; Tübingen Germany
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy; Institute of Pharmacy, University of Tübingen; Tübingen Germany
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15
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Schmidt S, Schneider S, Yang W, Liu G, Schmidt EM, Schmid E, Mia S, Brucker S, Stournaras C, Wallwiener D, Brosens JJ, Lang F. TGFβ1 and SGK1-sensitive store-operated Ca2+ entry and Orai1 expression in endometrial Ishikawa cells. Mol Hum Reprod 2013; 20:139-47. [PMID: 24043696 DOI: 10.1093/molehr/gat066] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The serum-and-glucocorticoid-inducible-kinase-1 (SGK1) is ubiquitously expressed and under genomic control by cell stress, hormones and further mediators. A most powerful stimulator of SGK1 expression is transforming growth factor TGFβ1. SGK1 is activated by insulin and growth factors via phosphatidylinositol-3-kinase and the 3-phosphoinositide-dependent kinase PDK1. As shown recently, SGK1 increases the store-operated Ca(2+) entry (SOCE), which is accomplished by the pore-forming ion channel unit Orai. Most recent observations further revealed that SGK1 plays a critical role in the regulation of fertility. SGK1 is up-regulated in the luminal epithelium of women with unexplained infertility but down-regulated in decidualizing stromal cells of patients with recurrent pregnancy loss. The present study explored whether Orai1 is expressed in endometrium and sensitive to regulation by SGK1 and/or TGFβ1. To this end, Orai1 protein abundance was determined by western blotting and SOCE by fura-2 fluorescence. As a result, Orai1 was expressed in human endometrium and in human endometrial Ishikawa cells. Orai1 expression and SOCE in Ishikawa cells were increased by transfection with constitutively active (S422D)SGK1 but not by transfection with inactive (K127N)SGK1. The difference of SOCE between (S422D)SGK1 and (K127N)SGK1-transfected cells was virtually abrogated in the presence of Orai1 inhibitor 2-aminoethoxydiphenyl borate (2-APB, 50 µM). Similar to (S422D)SGK1 transfection TGFβ1 treatment up-regulated both Orai1 protein abundance and SOCE. In conclusion, Orai1 is expressed in the human endometrium and is up-regulated by SGK1 and TGFβ1. The present observations thus uncover a novel element in SGK1-sensitive regulation of endometrial cells.
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Affiliation(s)
- S Schmidt
- Department of Physiology, University of Tübingen, D72076 Tübingen, Germany
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16
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Ranzinger J, Rustom A, Schwenger V. Potential role of nanotubes in context of clinical treatments? Commun Integr Biol 2013; 6:e22686. [PMID: 23802041 PMCID: PMC3689573 DOI: 10.4161/cib.22686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The recent awareness that eukaryotic cells can be linked and communicate via membranous nanotubes (NTs) has extended previous conceptions of cell-to-cell interaction. Apart from mediating functional connectivity between a broad range of cells, facilitating intercellular transmission of electric signals or various cellular components, there is strong evidence for participation of NTs in pathological processes of particular medical interest. In our recent study, we showed for the first time the existence of nanotubular connections between human primary peritoneal mesothelial cells (HPMCs) and provided insights to their actin/filopodia mediated building mechanism. Furthermore, we showed that tumor necrosis factor (TNF) significantly increased NT formation between HPMCs, pointing to a crucial role of NTs during inflammatory processes. Moreover, our study showed a strong correlation of NT occurrence and cellular cholesterol contents, demonstrating an interdependence of NT mediated cell communication, cytokine action and cholesterol homeostasis. Here, we further provide analysis on NT-formation processes.
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Affiliation(s)
- Julia Ranzinger
- Department of Nephrology; University of Heidelberg; Heidelberg, Germany
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17
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Pasham V, Pathare G, Fajol A, Rexhepaj R, Michael D, Pakladok T, Alesutan I, Rotte A, Föller M, Lang F. OSR1-sensitive small intestinal Na+ transport. Am J Physiol Gastrointest Liver Physiol 2012; 303:G1212-9. [PMID: 23019198 DOI: 10.1152/ajpgi.00367.2011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The oxidative stress responsive kinase 1 (OSR1) contributes to WNK (with no K)-dependent regulation of renal tubular salt transport, renal salt excretion, and blood pressure. Little is known, however, about a role of OSR1 in the regulation of intestinal salt transport. The present study thus explored whether OSR1 is expressed in intestinal tissue and whether small intestinal Na(+)/H(+) exchanger (NHE), small intestinal Na(+)-glucose cotransport (SGLT1), and/or colonic epithelium Na(+) channel (ENaC) differ between knockin mice carrying one allele of WNK-resistant OSR1 (osr1(+/KI)) and wild-type mice (osr1(+/+)). OSR1 protein abundance was determined by Western blotting, cytosolic pH from BCECF fluorescence, NHE activity from Na(+)-dependent realkalinization following an ammonium pulse, SGLT1 activity from glucose-induced current, and colonic ENaC activity from amiloride-sensitive transepithelial current in Ussing chamber experiments. As a result, OSR1 protein was expressed in small intestine of both osr1(+/KI) mice and osr1(+/+) mice. Daily fecal Na(+), K(+), and H(2)O excretion and jejunal SGLT1 activity were lower, whereas small intestinal NHE activity and colonic ENaC activity were higher in osr1(+/KI) mice than in osr1(+/+) mice. NHE3 inhibitor S-3226 significantly reduced NHE activity in both genotypes but did not abrogate the difference between the genotypes. Plasma osmolarity, serum antidiuretic hormone, plasma aldosterone, and plasma corticosterone concentrations were similar in both genotypes. Small intestinal NHE3 and colonic α-ENaC protein abundance were not significantly different between genotypes, but colonic phospho-β-ENaC (ser633) was significantly higher in osr1(+/KI) mice. In conclusion, OSR1 is expressed in intestine and partial WNK insensitivity of OSR1 increases intestinal NHE activity and colonic ENaC activity.
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Affiliation(s)
- Venkanna Pasham
- Department of Physiology, University of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany
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18
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Lang F, Eylenstein A, Shumilina E. Regulation of Orai1/STIM1 by the kinases SGK1 and AMPK. Cell Calcium 2012; 52:347-54. [PMID: 22682960 DOI: 10.1016/j.ceca.2012.05.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 05/07/2012] [Accepted: 05/09/2012] [Indexed: 01/08/2023]
Abstract
STIM and Orai isoforms orchestrate store operated Ca2+ entry (SOCE) and thus cytosolic Ca2+ fluctuations following stimulation by hormones, growth factors and further mediators. Orai1 is a target of Nedd4-2, an ubiquitin ligase preparing several plasma membrane proteins for degradation. Phosphorylation of Nedd4-2 by the serum and glucocorticoid inducible kinase SGK1 leads to the binding of Nedd4-2 to the protein 14-3-3 thus preventing its interaction with Orai1. Nedd4-2 is activated by the energy sensing AMP activated kinase AMPK. Thus, SGK1 disrupts and AMPK fosters degradation of Orai1. New synthesis of both, Orai1 and STIM1, is stimulated by the transcription factor NF-κB (nuclear factor kappa B), which binds to the respective promoter regions of the genes encoding STIM1 and Orai1. SGK1 upregulates and AMPK presumably downregulates NF-κB and thus de novo synthesis of Orai1 and STIM1 proteins. The regulation by SGK1 links SOCE to the signaling of a wide variety of hormones and growth factors, the AMPK dependent regulation of Orai1 and STIM1 may serve to limit inadequate activation of SOCE following energy depletion, which is otherwise expected to activate SOCE by depletion of intracellular Ca2+ stores due to impairment of the ATP consuming sarco/endoplasmatic reticulum Ca2+ ATPase SERCA.
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Affiliation(s)
- Florian Lang
- Department of Physiology, University of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany.
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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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Zhu XM, Yao FH, Yao YM, Dong N, Yu Y, Sheng ZY. Endoplasmic reticulum stress and its regulator XBP-1 contributes to dendritic cell maturation and activation induced by high mobility group box-1 protein. Int J Biochem Cell Biol 2012; 44:1097-105. [PMID: 22504285 DOI: 10.1016/j.biocel.2012.03.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 03/23/2012] [Accepted: 03/27/2012] [Indexed: 12/14/2022]
Abstract
High mobility group box-1 protein (HMGB1) had been proved to induce maturation and activation of dendritic cell (DC), however, the endogenous changes and mechanisms underlying are unknown. Since endoplasmic reticulum stress (ERS) activates an adaptive unfolded protein response (UPR) that facilitates cellular survival and repair, we hypothesized that HMGB1 may regulate the function of DC by modulating ERS. In our study, HMGB1 stimulation induced significant ERS responses in DCs in a time- and dose-dependent manner, demonstrated by the up-regulation of a number of ERS markers. Gene silence of XBP-1 in splenic DCs decreased the levels of CD80, CD86 as well as major histocompatibility complex (MHC)-II expression and cytokine secretion after HMGB1 treatment, when compared with untransfected or nontargeting-transfected DCs (all P<0.05). Moreover, XBP-1 silenced DCs after treatment with HMGB1 failed to stimulate notable proliferation and differentiation of T cells, unlike normal DCs or nontargeting-transfected DCs (all P<0.05). Gene silence of XBP-1 resulted in down-regulation of the receptor for advanced glycation end products (RAGE) expression on the surface of splenic DCs induced by HMGB1 stimulation (P<0.05). These findings demonstrate an important role for ERS and its regulator XBP-1 in HMGB1-induced maturation and activation of DCs.
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Affiliation(s)
- Xiao-mei Zhu
- Department of Microbiology and Immunology, Burns Institute, First Hospital Affiliated to the Chinese PLA General Hospital, Beijing 100048, PR China
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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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Pathar G, Föller M, Daryadel A, Mutig K, Bogatikov E, Fajol A, Almilaji A, Michael D, Stange G, Voelkl J, Wagner CA, Bachmann S, Lang F. OSR1-Sensitive Renal Tubular Phosphate Reabsorption. ACTA ACUST UNITED AC 2012; 36:149-61. [DOI: 10.1159/000343405] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2012] [Indexed: 02/06/2023]
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Wolden-Kirk H, Overbergh L, Christesen HT, Brusgaard K, Mathieu C. Vitamin D and diabetes: its importance for beta cell and immune function. Mol Cell Endocrinol 2011; 347:106-20. [PMID: 21889571 DOI: 10.1016/j.mce.2011.08.016] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 08/08/2011] [Accepted: 08/12/2011] [Indexed: 02/06/2023]
Abstract
Experimental evidence indicates that vitamin D may play a role in the defense against type 1 diabetes (T1D) as well as type 2 diabetes (T2D). Epidemiological data have established a link between vitamin D deficiency and an increased incidence of both T1D and T2D, whereas early and long-term vitamin D supplementation may decrease the risk of these disorders. The protective effects of vitamin D are mediated through the regulation of several components such as the immune system and calcium homeostasis. However, an increasing amount of evidence suggests that vitamin D also affects beta cells directly thereby rendering them more resistant to the types of cellular stress encountered during T1D and T2D. This review evaluates the role of vitamin D signaling in the pathogenesis of T1D and T2D with a special emphasis on the direct effects of vitamin D on pancreatic beta cells.
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Affiliation(s)
- Heidi Wolden-Kirk
- Laboratory of Experimental Medicine and Endocrinology, University Hospital Gasthuisberg, Catholic University of Leuven, B-3000 Leuven, Belgium.
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Eylenstein A, Schmidt S, Gu S, Yang W, Schmid E, Schmidt EM, Alesutan I, Szteyn K, Regel I, Shumilina E, Lang F. Transcription factor NF-κB regulates expression of pore-forming Ca2+ channel unit, Orai1, and its activator, STIM1, to control Ca2+ entry and affect cellular functions. J Biol Chem 2011; 287:2719-30. [PMID: 22110130 DOI: 10.1074/jbc.m111.275925] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The serum and glucocorticoid-inducible kinase SGK1 increases the activity of Orai1, the pore forming unit of store-operated Ca(2+) entry, and thus influences Ca(2+)-dependent cellular functions such as migration. SGK1 further regulates transcription factor nuclear factor κB (NF-κB). This study explored whether SGK1 influences transcription of Orai1 and/or STIM1, the Orai1-activating Ca(2+) sensor. Orai1 and STIM1 transcript levels were decreased in mast cells from SGK1 knock-out mice and increased in HEK293 cells transfected with active (S422D)SGK1 but not with inactive (K127N)SGK1 or in (S422D)SGK1-transfected cells treated with the NF-κB inhibitor Wogonin (100 μm). Treatment with the stem cell factor enhanced transcript levels of STIM1 and Orai1 in sgk1(+/+) but not in sgk1(-/-) mast cells and not in sgk1(+/+) cells treated with Wogonin. Orai1 and STIM1 transcript levels were further increased in sgk1(+/+) and sgk1(-/-) mast cells by transfection with active NF-κB subunit p65 as well as in HEK293 cells by transfection with NF-κB subunits p65/p50 or p65/p52. They were decreased by silencing of NF-κB subunits p65, p50, or p52 or by NF-κB inhibitor Wogonin (100 μm). Luciferase assay and chromatin immunoprecipitation defined NF-κB-binding sites in promoter regions accounting for NF-κB sensitive genomic regulation of STIM1 and Orai1. Store-operated Ca(2+) entry was similarly increased by overexpression of p65/p50 or p65/p52 and decreased by treatment with Wogonin. Transfection of HEK293 cells with p65/p50 or p65/p52 further augmented migration. The present observations reveal powerful genomic regulation of Orai1/STIM1 by SGK1-dependent NF-κB signaling.
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Affiliation(s)
- Anja Eylenstein
- Department of Physiology, University of Tübingen, Gmelinstrasse 5, D-72076 Tübingen, Germany
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Schmidt EM, Münzer P, Borst O, Kraemer BF, Schmid E, Urban B, Lindemann S, Ruth P, Gawaz M, Lang F. Ion channels in the regulation of platelet migration. Biochem Biophys Res Commun 2011; 415:54-60. [PMID: 22005466 DOI: 10.1016/j.bbrc.2011.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Accepted: 10/02/2011] [Indexed: 10/16/2022]
Abstract
Platelets have been shown to migrate and thus to invade the vascular wall. Platelet migration is stimulated by SDF-1. In other cell types, migration is dependent on Ca(2+) entry via Ca(2+) channels. Ca(2+) influx is sensitive to cell membrane potential which is maintained by K(+) channel activity and/or Cl(-) channel activity. The present study explored the role of ion channels in the regulation of SDF-1 induced migration. Platelets were isolated from human volunteers as well as from gene targeted mice lacking the Ca(2+) activated K(+) channel SK4 (sk4(-/-)) and their wild type littermates (sk4(+/+)). According to confocal microscopy human platelets expressed the Ca(2+) channel Orai1 and the Ca(2+)-activated K(+) channel K(Ca)3.1 (SK4). SDF-1 (100 ng/ml) stimulated migration in human platelets, an effect blunted by Orai1 inhibitors 2-aminoethoxydiphenyl borate 2-APB (10 μM) and SKF-96365 (10 μM), by unspecific K(+) channel inhibitor TEA (30 mM), by SK4 specific K(+) channel blocker clotrimazole (10 μM), but not by Cl(-) channel inhibitor 5-nitro-2-(3-phenylpropylamino) benzoic acid NPPB (100 μM). Significant stimulation of migration by SDF-1 was further observed in sk4(+/+) platelets but was virtually absent in sk4(-/-) platelets. In conclusion, platelet migration requires activity of the Ca(2+) channel Orai1 and of the Ca(2+) activated K(+) channel SK4, but not of NPPB-sensitive Cl(-) channels.
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26
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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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Beum PV, Lindorfer MA, Peek EM, Stukenberg PT, de Weers M, Beurskens FJ, Parren PWHI, van de Winkel JGJ, Taylor RP. Penetration of antibody-opsonized cells by the membrane attack complex of complement promotes Ca(2+) influx and induces streamers. Eur J Immunol 2011; 41:2436-46. [PMID: 21674476 DOI: 10.1002/eji.201041204] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 04/27/2011] [Accepted: 05/18/2011] [Indexed: 12/15/2022]
Abstract
We have reported that during complement-mediated cytolysis of B cells promoted by the CD20 mAbs rituximab or ofatumumab (OFA), long, thin structures that we call streamers (≥ 3 cell diameters) are rapidly generated and grow out from the cell surface. Streamers appear before cells are killed and contain opsonizing mAbs and membrane lipids. By exploiting the differential Ca(2+) requirements of discrete steps in the complement cascade, we determined that mAb-opsonized cells first tagged with C3b using C5-depleted serum are killed on addition of serum and EDTA, but the cells do not produce streamers. Also, cells first opsonized with OFA are lysed in serum containing Mg-EGTA by the alternative complement pathway but streamers are not produced. These findings indicate that Ca(2+) influx is necessary for streamer formation. Other mAbs that promote complement-mediated cytolysis also induce streamers on target cells. Streamer-like structures called nanotubes have been reported in several cellular systems, and are thought to promote intercellular communication/signaling. We tested whether this signaling could influence the susceptibility of neighboring cells contacted by streamers to complement attack and found that complement-mediated cytolysis of OFA-opsonized cells increases the resistance of unopsonized indicator cell populations to subsequent lysis when these cells are exposed to OFA and complement.
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Affiliation(s)
- Paul V Beum
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA
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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: 64] [Impact Index Per Article: 4.9] [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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Eylenstein A, Gehring EM, Heise N, Shumilina E, Schmidt S, Szteyn K, Münzer P, Nurbaeva MK, Eichenmüller M, Tyan L, Regel I, Föller M, Kuhl D, Soboloff J, Penner R, Lang F. Stimulation of Ca2+-channel Orai1/STIM1 by serum- and glucocorticoid-inducible kinase 1 (SGK1). FASEB J 2011; 25:2012-21. [PMID: 21385992 DOI: 10.1096/fj.10-178210] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Ca(2+) signaling includes store-operated Ca(2+) entry (SOCE) following depletion of endoplasmic reticulum (ER) Ca(2+) stores. On store depletion, the ER Ca(2+) sensor STIM1 activates Orai1, the pore-forming unit of Ca(2+)-release-activated Ca(2+) (CRAC) channels. Here, we show that Orai1 is regulated by serum- and glucocorticoid-inducible kinase 1 (SGK1), a growth factor-regulated kinase. Membrane Orai1 protein abundance, I(CRAC), and SOCE in human embryonic kidney (HEK293) cells stably expressing Orai1 and transfected with STIM1 were each significantly enhanced by coexpression of constitutively active (S422D)SGK1 (by+81, +378, and+136%, respectively) but not by inactive (K127N)SGK1. Coexpression of the ubiquitin ligase Nedd4-2, an established negatively regulated SGK1 target, down-regulated SOCE (by -48%) and I(CRAC) (by -60%), an effect reversed by expression of (S422D)SGK1 (by +175 and +173%, respectively). Orai1 protein abundance and SOCE were significantly lower in mast cells from SGK1-knockout (sgk1(-/-)) mice (by -37% and -52%, respectively) than in mast cells from wild-type (sgk1(+/+)) littermates. Activation of SOCE by sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase-inhibitor thapsigargin (2 μM) stimulated migration, an effect significantly higher (by +306%) in (S422D)SGK1-expressing than in (K127N)SGK1-expressing HEK293 cells, and also significantly higher (by +108%) in sgk1(+/+) than in sgk1(-/-) mast cells. SGK1 is thus a novel key player in the regulation of SOCE.
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Affiliation(s)
- Anja Eylenstein
- Department of Physiology, University of Tübingen, Gmelinstr. 5, D-72076 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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Condamine T, Le Texier L, Howie D, Lavault A, Hill M, Halary F, Cobbold S, Waldmann H, Cuturi MC, Chiffoleau E. Tmem176B and Tmem176A are associated with the immature state of dendritic cells. J Leukoc Biol 2010; 88:507-15. [PMID: 20501748 DOI: 10.1189/jlb.1109738] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
DCs play a central role in the development of innate and adaptive immunity but also in the induction and maintenance of immune tolerance. Identification of factors that govern DC activation, their maturation state, and their capacity to induce proinflammatory or tolerogeneic responses therefore represents a crucial aim of research. We previously identified a new molecule, Tmem176B (which we named TORID initially), as highly expressed in a model of allograft tolerance in the rat. We showed that its overexpression in rat DCs blocked their maturation, suggesting a role for this molecule in the maturation process. To characterize the function of Tmem176B further, we used a split-ubiquitin yeast, two-hybrid system to identify interacting partners and found that Tmem176B associated with itself but also with Tmem176A, a membrane protein similar to Tmem176B. Interestingly, these two molecules showed similar mRNA expression patterns among various murine tissues and immune cells and were both down-regulated following DC maturation. In addition, we showed that in using RNAi, these molecules are both involved in the maintenance of the immature state of the DCs. Taken together, these data suggest that Tmem176B and Tmem176A associate to form multimers and restrain DC maturation. Therefore, these two molecules may represent valid targets to regulate DC function.
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Affiliation(s)
- Thomas Condamine
- INSERM, U643, CHU Nantes, Institut de Transplantation et de Recherche en Transplantation, ITERT, and Université de Nantes, Faculté de Médecine, Nantes, France
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Abstract
Since their discovery by Steinman and Cohn in 1973, dendritic cells (DCs) have become increasingly recognized for their crucial role as regulators of innate and adaptive immunity. DCs are exquisitely adept at acquiring, processing, and presenting antigens to T cells. They also adjust the context (and hence the outcome) of antigen presentation in response to a plethora of environmental inputs that signal the occurrence of pathogens or tissue damage. Such signals generally boost DC maturation, which promotes their migration from peripheral tissues into and within secondary lymphoid organs and their capacity to induce and regulate effector T cell responses. Conversely, more recent observations indicate that DCs are also crucial to ensure immunological peace. Indeed, DCs constantly present innocuous self- and nonself-antigens in a fashion that promotes tolerance, at least in part, through the control of regulatory T cells (Tregs). Tregs are specialized T cells that exert their immunosuppressive function through a variety of mechanisms affecting both DCs and effector cells. Here, we review recent advances in our understanding of the relationship between tolerogenic DCs and Tregs.
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Affiliation(s)
- Anjana Rao
- Department of Pathology, Harvard Medical School, Boston, MA 02115, USA.
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