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Kiritsy MC, Ankley LM, Trombley J, Huizinga GP, Lord AE, Orning P, Elling R, Fitzgerald KA, Olive AJ. A genetic screen in macrophages identifies new regulators of IFNγ-inducible MHCII that contribute to T cell activation. eLife 2021; 10:65110. [PMID: 34747695 PMCID: PMC8598162 DOI: 10.7554/elife.65110] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 11/03/2021] [Indexed: 12/26/2022] Open
Abstract
Cytokine-mediated activation of host immunity is central to the control of pathogens. Interferon-gamma (IFNγ) is a key cytokine in protective immunity that induces major histocompatibility complex class II molecules (MHCII) to amplify CD4+ T cell activation and effector function. Despite its central role, the dynamic regulation of IFNγ-induced MHCII is not well understood. Using a genome-wide CRISPR-Cas9 screen in murine macrophages, we identified genes that control MHCII surface expression. Mechanistic studies uncovered two parallel pathways of IFNγ-mediated MHCII control that require the multifunctional glycogen synthase kinase three beta (GSK3β) or the mediator complex subunit 16 (MED16). Both pathways control distinct aspects of the IFNγ response and are necessary for IFNγ-mediated induction of the MHCII transactivator Ciita, MHCII expression, and CD4+ T cell activation. Our results define previously unappreciated regulation of MHCII expression that is required to control CD4+ T cell responses.
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Affiliation(s)
- Michael C Kiritsy
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
| | - Laurisa M Ankley
- Department of Microbiology & Molecular Genetics, College of Osteopathic Medicine, Michigan State University, East Lansing, United States
| | - Justin Trombley
- Department of Microbiology & Molecular Genetics, College of Osteopathic Medicine, Michigan State University, East Lansing, United States
| | - Gabrielle P Huizinga
- Department of Microbiology & Molecular Genetics, College of Osteopathic Medicine, Michigan State University, East Lansing, United States
| | - Audrey E Lord
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
| | - Pontus Orning
- Division of Infectious Disease and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, United States
| | - Roland Elling
- Division of Infectious Disease and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, United States
| | - Katherine A Fitzgerald
- Division of Infectious Disease and Immunology, Department of Medicine, University of Massachusetts Medical School, Worcester, United States
| | - Andrew J Olive
- Department of Microbiology & Molecular Genetics, College of Osteopathic Medicine, Michigan State University, East Lansing, United States
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León Machado JA, Steimle V. The MHC Class II Transactivator CIITA: Not (Quite) the Odd-One-Out Anymore among NLR Proteins. Int J Mol Sci 2021; 22:1074. [PMID: 33499042 PMCID: PMC7866136 DOI: 10.3390/ijms22031074] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/15/2021] [Accepted: 01/19/2021] [Indexed: 12/14/2022] Open
Abstract
In this review, we discuss the major histocompatibility complex (MHC) class II transactivator (CIITA), which is the master regulator of MHC class II gene expression. CIITA is the founding member of the mammalian nucleotide-binding and leucine-rich-repeat (NLR) protein family but stood apart for a long time as the only transcriptional regulator. More recently, it was found that its closest homolog, NLRC5 (NLR protein caspase activation and recruitment domain (CARD)-containing 5), is a regulator of MHC-I gene expression. Both act as non-DNA-binding activators through multiple protein-protein interactions with an MHC enhanceosome complex that binds cooperatively to a highly conserved combinatorial cis-acting module. Thus, the regulation of MHC-II expression is regulated largely through the differential expression of CIITA. In addition to the well-defined role of CIITA in MHC-II GENE regulation, we will discuss several other aspects of CIITA functions, such as its role in cancer, its role as a viral restriction element contributing to intrinsic immunity, and lastly, its very recently discovered role as an inhibitor of Ebola and SARS-Cov-2 virus replication. We will briefly touch upon the recently discovered role of NLRP3 as a transcriptional regulator, which suggests that transcriptional regulation is, after all, not such an unusual feature for NLR proteins.
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Affiliation(s)
| | - Viktor Steimle
- Département de Biologie, Université de Sherbrooke, 2500 Boul., Sherbrooke, QC J1K 2R1, Canada;
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3
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Protein arginine methyltransferase 1 (PRMT1) represses MHC II transcription in macrophages by methylating CIITA. Sci Rep 2017; 7:40531. [PMID: 28094290 PMCID: PMC5240148 DOI: 10.1038/srep40531] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 12/07/2016] [Indexed: 12/14/2022] Open
Abstract
Efficient presentation of alien antigens triggers activation of T lymphocytes and robust host defense against invading pathogens. This pathophysiological process relies on the expression of major histocompatibility complex (MHC) molecules in antigen presenting cells such as macrophages. Aberrant MHC II transactivation plays a crucial role in the pathogenesis of atherosclerosis. Class II transactivator (CIITA) mediates MHC II induction by interferon gamma (IFN-γ). CIITA activity can be fine-tuned at the post-translational level, but the mechanisms are not fully appreciated. We investigated the role of protein arginine methyltransferase 1 (PRMT1) in this process. We report here that CIITA interacted with PRMT1. IFN-γ treatment down-regulated PRMT1 expression and attenuated PRMT1 binding on the MHC II promoter. Over-expression of PRMT1 repressed MHC II promoter activity while PRMT1 depletion enhanced MHC II transactivation. Mechanistically, PRMT1 methylated CIITA and promoted CIITA degradation. Therefore, our data reveal a previously unrecognized role for PRMT1 in suppressing CIITA-mediated MHC II transactivation.
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Messina NL, Clarke CJP, Johnstone RW. Constitutive IFNα/β signaling maintains expression of signaling intermediaries for efficient cytokine responses. JAKSTAT 2016; 5:e1173804. [PMID: 27512617 DOI: 10.1080/21623996.2016.1173804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 03/29/2016] [Accepted: 03/29/2016] [Indexed: 01/14/2023] Open
Abstract
Interferons (IFNs) are a family of immunoregulatory cytokines with important roles in anti-viral and anti-tumor responses. Type I and II IFNs bind distinct receptors and are associated with different stages of the immune response. There is however, considerable crosstalk between these two cytokines with enhancement of IFNγ responses following IFNα/β priming and loss of IFNα/β receptor (IFNAR) resulting in diminished IFNγ responses. In this study, we sought to define the mechanism of crosstalk between the type I and II IFNs. Our previous reports demonstrated reduced expression of the canonically activated transcription factor signal transducer and activator of transcription (STAT)1, in cells lacking the IFNAR α chain (IFNAR1). Therefore, we used microarray analysis to determine whether reconstitution of STAT1 in IFNAR1-deficient cells was sufficient to restore IFNγ responses. We identified several biological pathways, including the MHC class I antigen presentation pathway, in which STAT1 reconstitution was able to significantly rescue IFNγ-mediated gene regulation in Ifnar1 (-/-) cells. Notably, we also found that in addition to low basal expression of STAT1, cells lacking the IFNAR1 also had aberrant expression of multiple other transcription factors and signaling intermediaries. The studies described herein demonstrate that basal and regulated expression of signaling intermediaries is a mechanism for crosstalk between cytokines including type I and II IFNs.
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Affiliation(s)
- Nicole L Messina
- Cancer Therapeutics Program, Peter MacCallum Cancer Center, East Melbourne, VIC, Australia; Department of Pathology, University of Melbourne, Parkville, VIC, Australia
| | | | - Ricky W Johnstone
- Cancer Therapeutics Program, Peter MacCallum Cancer Center, East Melbourne, VIC, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Australia
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5
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Bansal N, David G, Farias E, Waxman S. Emerging Roles of Epigenetic Regulator Sin3 in Cancer. Adv Cancer Res 2016; 130:113-35. [PMID: 27037752 DOI: 10.1016/bs.acr.2016.01.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Revolutionizing treatment strategies is an urgent clinical need in the fight against cancer. Recently the scientific community has recognized chromatin-associated proteins as promising therapeutic candidates. However, there is a need to develop more targeted epigenetic inhibitors with less toxicity. Sin3 family is one such target which consists of evolutionary conserved proteins with two paralogues Sin3A and Sin3B. Sin3A/B are global transcription regulators that provide a versatile platform for diverse chromatin-modifying activities. Sin3 proteins regulate key cellular functions that include cell cycle, proliferation, and differentiation, and have recently been implicated in cancer pathogenesis. In this chapter, we summarize the key concepts of Sin3 biology and elaborate the recent advancements in the role of Sin3 proteins in cancer with specific examples in multiple endocrine neoplasia type 2, pancreatic ductal adenocarcinoma, and triple negative breast cancer. Finally, a program to create an integrative approach for screening antitumor agents that target chromatin-associated factors like Sin3 is presented.
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Affiliation(s)
- N Bansal
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - G David
- New York University School of Medicine, New York, NY, United States
| | - E Farias
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - S Waxman
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
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6
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Fang M, Li P, Wu X, Xu Y. Class II transactivator (CIITA) mediates transcriptional repression of pdk4 gene by interacting with hypermethylated in cancer 1 (HIC1). J Biomed Res 2015; 29:308-15. [PMID: 26243517 PMCID: PMC4547379 DOI: 10.7555/jbr.29.20150055] [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] [Received: 04/07/2015] [Accepted: 05/09/2015] [Indexed: 12/30/2022] Open
Abstract
Increased accumulation and/or impaired utilization of fatty acid in extra-adipose tissues are implicated in the pathogenesis of insulin resistance and type 2 diabetes. Pyruvate dehydrogenase kinase 4 (Pdk4) is a key enzyme involved in fatty oxidation and energy expenditure, and its expression can be repressed by pro-inflammatory stimuli. Previously, we have shown that class II transactivator (CIITA) mediates the adverse effect of interferon gamma (IFN-γ) in skeletal muscle cells by cooperating with hypermethylated in cancer 1 (HIC1) to repress silent information regulator 1 (SIRT1) transcription. Building upon this finding, we report here that CIITA interacted with HIC1 via the GTP-binding domain (GBD) while HIC1 interacted with CIITA via the BTB/POZ domain. The GBD domain was required for CIITA to repress SIRT1 transcription probably acting as a bridge for CIITA to bind to HIC1 and consequently to bind to the SIRT1 promoter. IFN-γ stimulation, CIITA over-expression, or HIC1 over-expression repressed Pdk4 promoter activity while silencing either CIITA or HIC1 normalized Pdk4 expression in the presence of IFN-γ. An increase in SIRT1 expression or activity partially rescued Pdk4 expression in the presence of CIITA, but SIRT1 inhibition abrogated Pdk4 normalization even in the absence of CIITA. Taken together, our data have identified a HIC1-CIITA-SIRT1 axis that regulates Pdk4 transcription in response to IFN-γ stimulation.
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Affiliation(s)
- Mingming Fang
- Key Laboratory of Cardiovascular Disease, Department of Pathophysiology.,Department of Nursing, Jiangsu Jiankang Vocational University, Nanjing, Jiangsu 210029, China
| | - Ping Li
- Key Laboratory of Cardiovascular Disease, Department of Pathophysiology.,Department of Gastroenterology, Second Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210011, China
| | - Xiaoyan Wu
- Key Laboratory of Cardiovascular Disease, Department of Pathophysiology.,Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
| | - Yong Xu
- Key Laboratory of Cardiovascular Disease, Department of Pathophysiology.,Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu 210029, China.
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7
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Kadamb R, Mittal S, Bansal N, Saluja D. Stress-mediated Sin3B activation leads to negative regulation of subset of p53 target genes. Biosci Rep 2015; 35:e00234. [PMID: 26181367 PMCID: PMC4613689 DOI: 10.1042/bsr20150122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/03/2015] [Accepted: 06/19/2015] [Indexed: 11/28/2022] Open
Abstract
The multiprotein SWI-independent 3 (Sin3)-HDAC (histone deacetylase) corepressor complex mediates gene repression through its interaction with DNA-binding factors and recruitment of chromatin-modifying proteins on to the promoters of target gene. Previously, an increased expression of Sin3B and tumour suppressor protein, p53 has been established upon adriamycin treatment. We, now provide evidence that Sin3B expression is significantly up-regulated under variety of stress conditions and this response is not stress-type specific. We observed that Sin3B expression is significantly up-regulated both at transcript and at protein level upon DNA damage induced by bleomycin drug, a radiomimetic agent. This increase in Sin3B expression upon stress is found to be p53-dependent and is associated with enhanced interaction of Sin3B with Ser(15) phosphorylated p53. Binding of Sin3-HDAC repressor complex on to the promoters of p53 target genes influences gene regulation by altering histone modifications (H3K9me3 and H3K27me3) at target genes. Furthermore, knockdown of Sin3B by shRNA severely compromises p53-mediated gene repression under stress conditions. Taken together, these results suggest that stress-induced Sin3B activation is p53-dependent and is essential for p53-mediated repression of its selective target genes. The present study has an implication in understanding the transrepression mechanism of p53 under DNA damaging conditions.
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Affiliation(s)
- Rama Kadamb
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India
| | - Shilpi Mittal
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India
| | - Nidhi Bansal
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India
| | - Daman Saluja
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi-110007, India
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8
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The class II transactivator (CIITA) is regulated by post-translational modification cross-talk between ERK1/2 phosphorylation, mono-ubiquitination and Lys63 ubiquitination. Biosci Rep 2015; 35:BSR20150091. [PMID: 26181363 PMCID: PMC4613680 DOI: 10.1042/bsr20150091] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 06/11/2015] [Indexed: 02/01/2023] Open
Abstract
The class II transactivator (CIITA) is known as the master regulator for the major histocompatibility class II (MHC II) molecules. CIITA is dynamically regulated through a series of intricate post-translational modifications (PTMs). CIITA's role is to initiate transcription of MHC II genes, which are responsible for presenting extracellular antigen to CD4(+) T-cells. In the present study, we identified extracellular signal-regulated kinase (ERK)1/2 as the kinase responsible for phosphorylating the regulatory site, Ser(280), which leads to increased levels of mono-ubiquitination and an overall increase in MHC II activity. Further, we identify that CIITA is also modified by Lys(63)-linked ubiquitination. Lys(63) ubiquitinated CIITA is concentrated in the cytoplasm and following activation of ERK1/2, CIITA phosphorylation occurs and Lys=ubiquitinated CIITA translocates to the nucleus. CIITA ubiquitination and phosphorylation perfectly demonstrates how CIITA location and activity is regulated through PTM cross-talk. Identifying CIITA PTMs and understanding how they mediate CIITA regulation is necessary due to the critical role CIITA has in the initiation of the adaptive immune response.
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9
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Chiu E, Gold T, Fettig V, LeVasseur MT, Cressman DE. Identification of a nuclear export sequence in the MHC CIITA. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2015; 194:6102-11. [PMID: 25948812 DOI: 10.4049/jimmunol.1402026] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 04/02/2015] [Indexed: 01/15/2023]
Abstract
Initiation of an immune response through expression of MHC class II and related genes is under the control of the CIITA. Normally found in both the cytoplasm and nucleus, CIITA is tightly controlled by a variety of posttranslational modifications as well as interactions with other nuclear and cytoplasmic factors, whereas disruption of this dual subcellular localization impairs CIITA functioning and expression of target genes. Although CIITA has well-defined domains necessary for its nuclear import, the region responsible for the translocation of CIITA from the nucleus has not been characterized. In this study, we identify a leucine-rich motif at residues 717-724 that bears strong homology to known nuclear export sequence (NES) domains. Mutation of this region renders CIITA insensitive to treatment with leptomycin B, an inhibitor of nuclear export, whereas fusion of this domain to a heterologous GFP is sufficient to induce its export to the cytoplasm or cause its retention in the nucleus following leptomycin B treatment. Point mutations of specific leucine residues within the NES disrupt the normal subcellular distribution of the full-length CIITA, impair its ability to interact with the nuclear export factor CRM1, and enhance CIITA-induced gene expression from an MHC class II gene promoter. IFN-γ stimulation of class II genes is further enhanced by inhibiting the nuclear export of endogenous CIITA. Collectively, these data demonstrate the first identification of a specific NES within CIITA and place it among the other protein domains that contribute to the posttranslational regulation of CIITA activity.
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Affiliation(s)
- Emily Chiu
- Department of Biology, Sarah Lawrence College, Bronxville, NY 10708
| | - Theresa Gold
- Department of Biology, Sarah Lawrence College, Bronxville, NY 10708
| | - Veronica Fettig
- Department of Biology, Sarah Lawrence College, Bronxville, NY 10708
| | | | - Drew E Cressman
- Department of Biology, Sarah Lawrence College, Bronxville, NY 10708
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10
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Vargas-Alarcón G, Posadas-Romero C, Posadas-Sánchez R, Martínez-Alvarado R, González-Pacheco H, Martínez-Sánchez C, Martínez-Ríos MA, Juarez-Cedillo T, Ramirez-Fuentes S, Pérez-Méndez O, Fragoso JM. The variant rs8048002 T>C in intron 3 of the MHC2TA gene is associated with risk of developing acute coronary syndrome. Cytokine 2015; 71:268-71. [DOI: 10.1016/j.cyto.2014.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 11/27/2022]
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11
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Weng X, Cheng X, Wu X, Xu H, Fang M, Xu Y. Sin3B mediates collagen type I gene repression by interferon gamma in vascular smooth muscle cells. Biochem Biophys Res Commun 2014; 447:263-70. [DOI: 10.1016/j.bbrc.2014.03.140] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 11/26/2022]
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12
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Kadamb R, Mittal S, Bansal N, Batra H, Saluja D. Sin3: insight into its transcription regulatory functions. Eur J Cell Biol 2013; 92:237-46. [PMID: 24189169 DOI: 10.1016/j.ejcb.2013.09.001] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 08/27/2013] [Accepted: 09/11/2013] [Indexed: 10/26/2022] Open
Abstract
Sin3, a large acidic protein, shares structural similarity with the helix-loop-helix dimerization domain of proteins of the Myc family of transcription factors. Sin3/HDAC corepressor complex functions in transcriptional regulation of several genes and is therefore implicated in the regulation of key biological processes. Knockdown studies have confirmed the role of Sin3 in cellular proliferation, differentiation, apoptosis and cell cycle regulation, emphasizing Sin3 as an essential regulator of critical cellular events in normal and pathological processes. The present review covers the diverse functions of this master transcriptional regulator as well as illustrates the redundant and distinct functions of its two mammalian isoforms.
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Affiliation(s)
- Rama Kadamb
- Dr. B.R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi 110007, India.
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13
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The MHC2TA 1614 C>G gene polymorphism is associated with risk of developing acute coronary syndrome. Mol Immunol 2013; 55:424-8. [DOI: 10.1016/j.molimm.2013.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 02/21/2013] [Accepted: 02/25/2013] [Indexed: 11/19/2022]
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14
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Ponticos M, Smith BD. Extracellular matrix synthesis in vascular disease: hypertension, and atherosclerosis. J Biomed Res 2013; 28:25-39. [PMID: 24474961 PMCID: PMC3904172 DOI: 10.7555/jbr.27.20130064] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 05/28/2013] [Accepted: 06/18/2013] [Indexed: 12/18/2022] Open
Abstract
Extracellular matrix (ECM) within the vascular network provides both a structural and regulatory role. The ECM is a dynamic composite of multiple proteins that form structures connecting cells within the network. Blood vessels are distended by blood pressure and, therefore, require ECM components with elasticity yet with enough tensile strength to resist rupture. The ECM is involved in conducting mechanical signals to cells. Most importantly, ECM regulates cellular function through chemical signaling by controlling activation and bioavailability of the growth factors. Cells respond to ECM by remodeling their microenvironment which becomes dysregulated in vascular diseases such hypertension, restenosis and atherosclerosis. This review examines the cellular and ECM components of vessels, with specific emphasis on the regulation of collagen type I and implications in vascular disease.
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Affiliation(s)
- Markella Ponticos
- Centre for Rheumatology & Connective Tissue Diseases, Division of Medicine-Inflammation, Royal Free & University College Medical School, University College London, London NW3 2PF, UK
| | - Barbara D Smith
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
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15
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Forlani G, Abdallah R, Accolla RS, Tosi G. The MHC-II transactivator CIITA, a restriction factor against oncogenic HTLV-1 and HTLV-2 retroviruses: similarities and differences in the inhibition of Tax-1 and Tax-2 viral transactivators. Front Microbiol 2013; 4:234. [PMID: 23986750 PMCID: PMC3749491 DOI: 10.3389/fmicb.2013.00234] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 07/30/2013] [Indexed: 11/13/2022] Open
Abstract
The activation of CD4(+) T helper cells is strictly dependent on the presentation of antigenic peptides by MHC class II (MHC-II) molecules. MHC-II expression is primarily regulated at the transcriptional level by the AIR-1 gene product CIITA (class II transactivator). Thus, CIITA plays a pivotal role in the triggering of the adaptive immune response against pathogens. Besides this well known function, we recently found that CIITA acts as an endogenous restriction factor against HTLV-1 (human T cell lymphotropic virus type 1) and HTLV-2 oncogenic retroviruses by targeting their viral transactivators Tax-1 and Tax-2, respectively. Here we review our findings on CIITA-mediated inhibition of viral replication and discuss similarities and differences in the molecular mechanisms by which CIITA specifically counteracts the function of Tax-1 and Tax-2 molecules. The dual function of CIITA as a key regulator of adaptive and intrinsic immunity represents a rather unique example of adaptation of host-derived factors against pathogen infections during evolution.
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Affiliation(s)
| | | | - Roberto S. Accolla
- Laboratory of General Pathology and Immunology, Department of Surgical and Morphological Sciences, University of InsubriaVarese, Italy
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16
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Delgadillo H, Vargas-Alarcón G, Gómez-Monterrosas O, Martínez-Rodríguez N, Ramírez-Fuentes S, Carrillo-Sánchez S, Peña-Duque MA, Martínez-Ríos MA, Pérez-Méndez O, Fragoso JM. The MHC2TA gene polymorphisms are not associated with restenosis after coronary stenting in Mexican patients. ARCHIVOS DE CARDIOLOGIA DE MEXICO 2012; 82:208-13. [DOI: 10.1016/j.acmx.2012.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 02/15/2012] [Accepted: 04/17/2012] [Indexed: 11/30/2022] Open
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17
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Li P, Zhao Y, Wu X, Xia M, Fang M, Iwasaki Y, Sha J, Chen Q, Xu Y, Shen A. Interferon gamma (IFN-γ) disrupts energy expenditure and metabolic homeostasis by suppressing SIRT1 transcription. Nucleic Acids Res 2011; 40:1609-20. [PMID: 22064865 PMCID: PMC3287208 DOI: 10.1093/nar/gkr984] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Chronic inflammation impairs metabolic homeostasis and is intimately correlated with the pathogenesis of type 2 diabetes. The pro-inflammatory cytokine IFN-γ is an integral part of the metabolic inflammation circuit and contributes significantly to metabolic dysfunction. The underlying mechanism, however, remains largely unknown. In the present study, we report that IFN-γ disrupts the expression of genes key to cellular metabolism and energy expenditure by repressing the expression and activity of SIRT1 at the transcription level. Further analysis reveals that IFN-γ requires class II transactivator (CIITA) to repress SIRT1 transcription. CIITA, once induced by IFN-γ, is recruited to the SIRT1 promoter by hypermethylated in cancer 1 (HIC1) and promotes down-regulation of SIRT1 transcription via active deacetylation of core histones surrounding the SIRT1 proximal promoter. Silencing CIITA or HIC1 restores SIRT1 activity and expression of metabolic genes in skeletal muscle cells challenged with IFN-γ. Therefore, our data delineate an IFN-γ/HIC1/CIITA axis that contributes to metabolic dysfunction by suppressing SIRT1 transcription in skeletal muscle cells and as such shed new light on the development of novel therapeutic strategies against type 2 diabetes.
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Affiliation(s)
- Ping Li
- State Key Laboratory of Reproductive Medicine and Department of Pathophysiology, Key Laboratory of Cardiovascular Disease,The Second Affiliated Hospital, Nanjing Medical University, Nanjing, China
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18
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Bansal N, Kadamb R, Mittal S, Vig L, Sharma R, Dwarakanath BS, Saluja D. Tumor suppressor protein p53 recruits human Sin3B/HDAC1 complex for down-regulation of its target promoters in response to genotoxic stress. PLoS One 2011; 6:e26156. [PMID: 22028823 PMCID: PMC3197607 DOI: 10.1371/journal.pone.0026156] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 09/21/2011] [Indexed: 11/18/2022] Open
Abstract
Master regulator protein p53, popularly known as the “guardian of genome” is the hub for regulation of diverse cellular pathways. Depending on the cell type and severity of DNA damage, p53 protein mediates cell cycle arrest or apoptosis, besides activating DNA repair, which is apparently achieved by regulation of its target genes, as well as direct interaction with other proteins. p53 is known to repress target genes via multiple mechanisms one of which is via recruitment of chromatin remodelling Sin3/HDAC1/2 complex. Sin3 proteins (Sin3A and Sin3B) regulate gene expression at the chromatin-level by serving as an anchor onto which the core Sin3/HDAC complex is assembled. The Sin3/HDAC co-repressor complex can be recruited by a large number of DNA-binding transcription factors. Sin3A has been closely linked to p53 while Sin3B is considered to be a close associate of E2Fs. The theme of this study was to establish the role of Sin3B in p53-mediated gene repression. We demonstrate a direct protein-protein interaction between human p53 and Sin3B (hSin3B). Amino acids 1–399 of hSin3B protein are involved in its interaction with N-terminal region (amino acids 1–108) of p53. Genotoxic stress induced by Adriamycin treatment increases the levels of hSin3B that is recruited to the promoters of p53-target genes (HSPA8, MAD1 and CRYZ). More importantly recruitment of hSin3B and repression of the three p53-target promoters upon Adriamycin treatment were observed only in p53+/+ cell lines. Additionally an increased tri-methylation of the H3K9 residue at the promoters of HSPA8 and CRYZ was also observed following Adriamycin treatment. The present study highlights for the first time the essential role of Sin3B as an important associate of p53 in mediating the cellular responses to stress and in the transcriptional repression of genes encoding for heat shock proteins or proteins involved in regulation of cell cycle and apoptosis.
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Affiliation(s)
- Nidhi Bansal
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Rama Kadamb
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Shilpi Mittal
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Leena Vig
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | - Raisha Sharma
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
| | | | - Daman Saluja
- Dr. B. R. Ambedkar Center for Biomedical Research, University of Delhi, Delhi, India
- * E-mail:
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Bhat KP, Truax AD, Greer SF. Phosphorylation and ubiquitination of degron proximal residues are essential for class II transactivator (CIITA) transactivation and major histocompatibility class II expression. J Biol Chem 2010; 285:25893-903. [PMID: 20538595 PMCID: PMC2923977 DOI: 10.1074/jbc.m110.127746] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 05/06/2010] [Indexed: 11/06/2022] Open
Abstract
Major histocompatibility (MHC) class II molecules are cell surface glycoproteins that present extracellular antigens to CD4(+) T cells and are essential for initiation of the adaptive immune response. MHC class II expression requires recruitment of a master regulator, the class II transactivator (CIITA), to the MHC class II promoter. Post-translational modifications to CIITA play important roles in modulating CIITA mediated transcription of various genes in different cell types. We have previously linked regulation of CIITA to the Ubiquitin Proteasome System (UPS), and we and others have demonstrated that mono-ubiquitination of CIITA dramatically increases its transactivity whereas poly-ubiquitination leads to CIITA degradation. Here we identify three degron proximal lysine residues, Lys-315, Lys-330, and Lys-333, and a phosphorylation site, Ser-280, located within the CIITA degron, that regulate CIITA ubiquitination, stability, and MHC class II expression. Together, these findings contribute to the developing post-translational modification code for CIITA.
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Affiliation(s)
- Kavita Purnanda Bhat
- From the Division of Cellular and Molecular Biology and Physiology, Department of Biology, Georgia State University, Atlanta, Georgia 30302
| | - Agnieszka Dorota Truax
- From the Division of Cellular and Molecular Biology and Physiology, Department of Biology, Georgia State University, Atlanta, Georgia 30302
| | - Susanna Fletcher Greer
- From the Division of Cellular and Molecular Biology and Physiology, Department of Biology, Georgia State University, Atlanta, Georgia 30302
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20
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Xu Y, Luchsinger L, Lucey EC, Smith BD. The effect of class II transactivator mutations on bleomycin-induced lung inflammation and fibrosis. Am J Respir Cell Mol Biol 2010; 44:898-905. [PMID: 20705943 DOI: 10.1165/rcmb.2009-0416oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
IFN-γ expression increases during the inflammatory response after bleomycin injury in mice. IFN-γ deficiency attenuates lung inflammation and fibrosis. Because IFN-γ stimulates class II transactivator (CIITA) expression, which activates major histocompatibility class (MHC) II and represses collagen expression, it was hypothesized that CIITA mediates IFN-γ action after bleomycin injury. To test this hypothesis, two CIITA mouse lines, one carrying a mutation of the leucine-rich region of CIITA (CIITA C-/-) and one with a deletion extending into the GTP-binding domain (CIITA G-/-), were used. IFN-γ treatment of lung cells isolated from both strains of mice induced mutant CIITA expression, which did not activate MHC II transcription. Collagen expression was similar in both mutant mouse strains and comparable to C57BL/6 (wild-type) mice. When mice were exposed to intratracheal bleomycin, both strains of CIITA mutant mice retained body weight and altered inflammation at 14 days after bleomycin injury compared with bleomycin-treated wild-type mice. However, there was no difference in fibrosis as judged by histology, mRNA, and protein expression of lungs. Bronchoalveolar lavage cells from CIITA C-/- and C57BL/6 lungs were examined at 3, 7, and 14 days after bleomycin injury. CD4 mRNA expression in bronchoalveolar lavage cells was down-regulated, whereas IL-4 and IL-10 expression was up-regulated, in CIITA C-/- mice, indicating a diminished, skewed Th2 response. The expression of IFN-γ was the same in all mice tested. Combined, our data suggest that CIITA mutations altered the immune response without affecting fibrosis.
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Affiliation(s)
- Yong Xu
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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21
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Beurel E, Michalek SM, Jope RS. Innate and adaptive immune responses regulated by glycogen synthase kinase-3 (GSK3). Trends Immunol 2009; 31:24-31. [PMID: 19836308 DOI: 10.1016/j.it.2009.09.007] [Citation(s) in RCA: 313] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 09/21/2009] [Accepted: 09/23/2009] [Indexed: 11/30/2022]
Abstract
In just a few years, the view of glycogen synthase kinase-3 (GSK3) has been transformed from an obscure enzyme seldom encountered in the immune literature to one implicated in an improbably large number of roles. GSK3 is a crucial regulator of the balance between pro- and anti-inflammatory cytokine production in both the periphery and the central nervous system, so that GSK3 inhibitors such as lithium can diminish inflammation. GSK3 influences T-cell proliferation, differentiation and survival. Many effects stem from GSK3 regulation of critical transcription factors, such as NF-kappaB, NFAT and STATs. These discoveries led to the rapid application of GSK3 inhibitors to animal models of sepsis, arthritis, colitis, multiple sclerosis and others, demonstrating their potential for therapeutic intervention.
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Affiliation(s)
- Eléonore Beurel
- Department of Psychiatry, University of Alabama at Birmingham, Birmingham, AL 35294-0017, USA
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Regulating the activity of class II transactivator by posttranslational modifications: exploring the possibilities. Mol Cell Biol 2009; 29:5639-44. [PMID: 19720744 DOI: 10.1128/mcb.00661-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
First identified as the master regulator of major histocompatibility complex II transcription, class II transactivator (CIITA) has since been implicated in a host of pathologies by modulating the transcription of multiple different genes. How CIITA caters to cell- and tissue-specific transcriptional needs is hotly debated and investigated. One of the possible mechanisms underlying spatiotemporal control of CIITA transcriptional activity is the posttranslational modification (PTM) machinery that refines certain amino acid residues of CIITA and hence alters its activity in response to specific cellular and environmental cues. This review discusses our current understanding of the PTM map of CIITA, how these modifications fine-tune its activity, and how the study of this area may lead to potential therapeutic strategies.
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Grzenda A, Lomberk G, Zhang JS, Urrutia R. Sin3: master scaffold and transcriptional corepressor. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2009; 1789:443-50. [PMID: 19505602 DOI: 10.1016/j.bbagrm.2009.05.007] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 05/21/2009] [Accepted: 05/26/2009] [Indexed: 11/17/2022]
Abstract
Sin3 was isolated over two decades ago as a negative regulator of transcription in budding yeast. Subsequent research has established the protein as a master transcriptional scaffold and corepressor capable of transcriptional silencing via associated histone deacetylases (HDACs). The core Sin3-HDAC complex interacts with a wide variety of repressors and corepressors, providing flexibility and expanded specificity in modulating chromatin structure and transcription. As a result, the Sin3/HDAC complex is involved in an array of biological and cellular processes, including cell cycle progression, genomic stability, embryonic development, and homeostasis. Abnormal recruitment of this complex or alteration of its enzymatic activity has been implicated in neoplastic transformation.
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Affiliation(s)
- Adrienne Grzenda
- Department of Biochemistry, Mayo Clinic, Rochester, MN 55905, USA
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Chan MMP, Cheung BKW, Li JCB, Chan LLY, Lau ASY. A role for glycogen synthase kinase-3 in antagonizing mycobacterial immune evasion by negatively regulating IL-10 induction. J Leukoc Biol 2009; 86:283-91. [PMID: 19401395 DOI: 10.1189/jlb.0708442] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Mtb dysregulates monocyte/macrophage functions to produce a large amount of the immunosuppressive cytokine IL-10. An important function of IL-10 in promoting Mtb survival is the suppression of antigen presentation of monocytes/macrophages to T cells. This dampens the host immune responses and provides an opportunity for immune evasion. GSK3 has been shown to control the balance between pro- and anti-inflammatory cytokine productions. Here, we investigated whether GSK3 regulates IL-10 expression and mediates a protective role upon live mycobacterial challenge using BCG as a model. Our results showed that BCG increased Akt phosphorylation and inhibited GSK3 activity, resulting in increased IL-10 production. We confirmed further that suppression of GSK3 activities by a specific chemical inhibitor strongly enhanced BCG-induced IL-10 production. We also showed that IL-10 secreted by BCG-infected human PBMo was a major suppressor of subsequent IFN-gamma production by PBMC and HLA-DR expression on PBMo in response to BCG. Neutralization of PBMo-secreted IL-10 by anti-IL-10 antibodies restored the IFN-gamma production and HLA-DR surface expression. Taken together, GSK3 negatively regulates mycobacteria-induced IL-10 production in human PBMo. The kinase may play a role in restoring IFN-gamma secretions and subsequent antigen presentation in response to mycobacterial infection. In conclusion, our results suggest a significant role for GSK3 in guarding against mycobacterial evasion of immunity via IL-10 induction in the host.
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Affiliation(s)
- Mabel M P Chan
- Department of Pediatrics and Adolescent Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
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HDAC2 deacetylates class II transactivator and suppresses its activity in macrophages and smooth muscle cells. J Mol Cell Cardiol 2009; 46:292-9. [DOI: 10.1016/j.yjmcc.2008.10.023] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2008] [Revised: 10/24/2008] [Accepted: 10/28/2008] [Indexed: 12/24/2022]
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Xu Y, Ravid K, Smith BD. Major histocompatibility class II transactivator expression in smooth muscle cells from A2b adenosine receptor knock-out mice: cross-talk between the adenosine and interferon-gamma signaling. J Biol Chem 2008; 283:14213-20. [PMID: 18359773 DOI: 10.1074/jbc.m708657200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Atherosclerosis characterized by sustained inflammation and aberrant extracellular matrix alterations. Our previous investigation has defined major histocompatibility class II transactivator (CIITA) as a key factor in mediating these two processes in smooth muscle cells. Here, we demonstrate that CIITA and major histocompatibility class II expression are elevated in interferon-gamma (IFN-gamma)-treated smooth muscle cells from A2b adenosine receptor (A2bAR(-/-)) knock-out mice, as compared with wild type cells. An A2-type adenosine receptor agonist suppresses these effects of IFN-gamma in wild type cells, which can be blocked by an A2bAR-specific antagonist. We further identify that increased cellular cAMP levels are responsible for the down-regulation of CIITA expression and, hence, reduced IFN-gamma response as evidenced by the following data: 1) direct activation of adenylyl cyclase activity is both necessary and sufficient to suppress the IFN-gamma response; 2) inhibition of phosphodiesterase activity attenuates IFN-gamma induced transcription events; and 3) direct treatment with cAMP analog abrogates CIITA activation and IFN-gamma response. Therefore, our data establish possible cross-talk between the adenosine signaling through cAMP and IFN-gamma during regulation of CIITA expression.
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Affiliation(s)
- Yong Xu
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
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