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Zhao Y, Xiong J, Chen HX, Zhang M, Zhou LN, Wu YF, Li WJ, Fei X, Li F, Zhu C, Li W, Ying SM, Wang L, Chen ZH, Shen HH. A Spontaneous H2-Aa Point Mutation Impairs MHC II Synthesis and CD4+ T-Cell Development in Mice. Front Immunol 2022; 13:810824. [PMID: 35309308 PMCID: PMC8931304 DOI: 10.3389/fimmu.2022.810824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/10/2022] [Indexed: 11/30/2022] Open
Abstract
Major histocompatibility complex class II (MHC II) is an essential immune regulatory molecule that plays an important role in antigen presentation and T-cell development. Abnormal MHC II expression can lead to immunodeficiency, clinically termed as type II bare lymphocyte syndrome (BLS), which usually results from mutations in the MHC II transactivator (CIITA) and other coactivators. Here, we present a new paradigm for MHC II deficiency in mice that involves a spontaneous point mutation on H2-Aa. A significantly reduced population of CD4+ T cells was observed in mice obtained from the long-term homozygous breeding of autophagy-related gene microtubule-associated protein 1 light chain 3 β (Map1lc3b, Lc3b) knockout mice; this phenotype was not attributed to the original knocked-out gene. MHC II expression was generally reduced, together with a marked deficiency of H2-Aa in the immune cells of these mice. Using cDNA and DNA sequencing, a spontaneous H2-Aa point mutation that led to false pre-mRNA splicing, deletion of eight bases in the mRNA, and protein frameshift was identified in these mice. These findings led to the discovery of a new type of spontaneous MHC II deficiency and provided a new paradigm to explain type II BLS in mice.
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Affiliation(s)
- Yun Zhao
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Juan Xiong
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
- Department of Drug Candidate, Qihan Bio Inc., Hangzhou, China
| | - Hai-Xia Chen
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Min Zhang
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Li-Na Zhou
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China
| | - Yin-Fang Wu
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Wei-Jie Li
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Xia Fei
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Fei Li
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Chen Zhu
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Wen Li
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Song-Min Ying
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
- International Institutes of Medicine, the Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, China
| | - Lie Wang
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China
- *Correspondence: Hua-Hao Shen, ; Zhi-Hua Chen, ; Lie Wang,
| | - Zhi-Hua Chen
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
- *Correspondence: Hua-Hao Shen, ; Zhi-Hua Chen, ; Lie Wang,
| | - Hua-Hao Shen
- Key Laboratory of Respiratory Disease of Zhejiang Province, Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
- State Key Lab of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou, China
- *Correspondence: Hua-Hao Shen, ; Zhi-Hua Chen, ; Lie Wang,
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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: 31] [Impact Index Per Article: 10.3] [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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Development of potent class II transactivator gene delivery systems capable of inducing de novo MHC II expression in human cells, in vitro and ex vivo. Gene Ther 2017; 24:342-352. [PMID: 28414303 DOI: 10.1038/gt.2017.25] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 02/01/2017] [Accepted: 02/06/2017] [Indexed: 01/17/2023]
Abstract
Class II transactivator (CIITA) induces transcription of major histocompatibility complex (MHC) II genes and can potentially be used to improve genetic immunotherapies by converting non-immune cells into cells capable of presenting antigens to CD4+ T cells. However, CIITA expression is tightly controlled and it remains unclear whether distinct non-immune cells differ in this transactivator regulation. Here we describe the development of gene delivery systems capable of promoting the efficient CIITA expression in non-immune cell lines and in primary human cells of an ex vivo skin explant model. Different human cell types undergoing CIITA overexpression presented high-level de novo expression of MHC II, validating the delivery systems as suitable tools for the CIITA evaluation as a molecular adjuvant for gene therapies.
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Suzuki K, Luo Y. Histone Acetylation and the Regulation of Major Histocompatibility Class II Gene Expression. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2017; 106:71-111. [PMID: 28057216 DOI: 10.1016/bs.apcsb.2016.08.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Major histocompatibility complex (MHC) class II molecules are essential for processing and presenting exogenous pathogen antigens to activate CD4+ T cells. Given their central role in adaptive immune responses, MHC class II genes are tightly regulated in a tissue- and activation-specific manner. The regulation of MHC class II gene expression involves various transcription factors that interact with conserved proximal cis-acting regulatory promoter elements, as well as MHC class II transactivator that interacts with a variety of chromatin remodeling machineries. Recent studies also identified distal regulatory elements within MHC class II gene locus that provide enormous insight into the long-range coordination of MHC class II gene expression. Novel therapeutic modalities that can modify MHC class II genes at the epigenetic level are emerging and are currently in preclinical and clinical trials. This review will focus on the role of chromatin remodeling, particularly remodeling that involves histone acetylation, in the constitutive and inducible regulation of MHC class II gene expression.
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Affiliation(s)
- K Suzuki
- Faculty of Medical Technology, Teikyo University, Itabashi, Japan.
| | - Y Luo
- Faculty of Medical Technology, Teikyo University, Itabashi, Japan
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Beaulieu YB, Leon Machado JA, Ethier S, Gaudreau L, Steimle V. Degradation, Promoter Recruitment and Transactivation Mediated by the Extreme N-Terminus of MHC Class II Transactivator CIITA Isoform III. PLoS One 2016; 11:e0148753. [PMID: 26871568 PMCID: PMC4752451 DOI: 10.1371/journal.pone.0148753] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 01/22/2016] [Indexed: 12/17/2022] Open
Abstract
Multiple relationships between ubiquitin-proteasome mediated protein turnover and transcriptional activation have been well documented, but the underlying mechanisms are still poorly understood. One way to induce degradation is via ubiquitination of the N-terminal α-amino group of proteins. The major histocompatibility complex (MHC) class II transactivator CIITA is the master regulator of MHC class II gene expression and we found earlier that CIITA is a short-lived protein. Using stable and transient transfections of different CIITA constructs into HEK-293 and HeLa cell lines, we show here that the extreme N-terminal end of CIITA isoform III induces both rapid degradation and transactivation. It is essential that this sequence resides at the N-terminal end of the protein since blocking of the N-terminal end with an epitope-tag stabilizes the protein and reduces transactivation potential. The first ten amino acids of CIITA isoform III act as a portable degron and transactivation sequence when transferred as N-terminal extension to truncated CIITA constructs and are also able to destabilize a heterologous protein. The same is observed with the N-terminal ends of several known N-terminal ubiquitination substrates, such as Id2, Cdt1 and MyoD. Arginine and proline residues within the N-terminal ends contribute to rapid turnover. The N-terminal end of CIITA isoform III is responsible for efficient in vivo recruitment to the HLA-DRA promoter and increased interaction with components of the transcription machinery, such as TBP, p300, p400/Domino, the 19S ATPase S8, and the MHC-II promoter binding complex RFX. These experiments reveal a novel function of free N-terminal ends of proteins in degradation-dependent transcriptional activation.
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Affiliation(s)
- Yves B. Beaulieu
- Département de biologie, Université de Sherbrooke, Sherbrooke, Qc, Canada
| | | | - Sylvain Ethier
- Département de biologie, Université de Sherbrooke, Sherbrooke, Qc, Canada
| | - Luc Gaudreau
- Département de biologie, Université de Sherbrooke, Sherbrooke, Qc, Canada
| | - Viktor Steimle
- Département de biologie, Université de Sherbrooke, Sherbrooke, Qc, Canada
- * E-mail:
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Selective modulation of MHC class II chaperons by a novel IFN-γ-inducible class II transactivator variant in lung adenocarcinoma A549 cells. Biochem Biophys Res Commun 2013; 440:190-5. [PMID: 24055710 DOI: 10.1016/j.bbrc.2013.09.066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 09/12/2013] [Indexed: 11/20/2022]
Abstract
Class II transactivator (CIITA) plays a critical role in controlling major histocompatibility complex (MHC) class II gene expression. In this study, two novel alternatively spliced variants of human interferon (IFN)-γ-inducible CIITA, one missing exon 7 (CIITAΔE7), the other with TAG inserted at exon 4/5 junction (CIITA-TAG), were identified and characterized. Both variants are naturally occurring since they are present in primary cells. Unlike CIITA-TAG, CIITAΔE7 is expressed more abundantly in lung adenocarcinoma A549 cells than in the non-transformed counterpart BEAS-2B cells following IFN-γ stimulation. Transfection experiments showed that CIITAΔE7 induced a markedly lower level of surface HLA-DR, -DP, -DQ expression than CIITA-TAG in A549 cells but not in BEAS-2B cells, although both variants elicited similar amounts of total DR, DP, and DQ proteins. This differential effect was correlated with, in A549 cells, decreased expression of Ii and HLA-DM genes, along with increased expression of HLA-DO genes. Ii and HLA-DM are chaperons assisting in HLA class II assembly, while HLA-DO functions to inhibit endosomal peptide loading and HLA class II membrane transport. These findings raise the possibility that CIITAΔE7 interacts with unknown cancer-associated factors to selectively modulate genes involved in the assembly and transport of HLA class II molecules.
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Shrestha D, Szöllosi J, Jenei A. Bare lymphocyte syndrome: an opportunity to discover our immune system. Immunol Lett 2011; 141:147-57. [PMID: 22027563 DOI: 10.1016/j.imlet.2011.10.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 09/30/2011] [Accepted: 10/11/2011] [Indexed: 11/27/2022]
Abstract
Bare lymphocyte syndrome (BLS) is a rare immunodeficiency disorder manifested by the partial or complete disappearance of major histocompatibility complex (MHC) proteins from the surface of the cells. Based on this specific feature, it is categorized into three different types depending on which type of MHC protein is affected. These proteins are mainly involved in generating the effective immune responses by differentiating 'self' from 'non-self' antigens through a process referred to as antigen presentation. Investigations on BLS have immensely contributed to our understanding of the transcriptional regulation of these molecules and have led to the discovery of several important proteins of the antigen presentation pathway. Reviews on this subject consistently project type II BLS, MHC II deficiency as BLS syndrome, although literatures' document cases of other types of BLS too. Therefore, in this article, we have assembled information on the BLS syndrome to produce a systematic narration while emphasizing the importance of BLS system in studying various aspects of immune biology.
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Affiliation(s)
- Dilip Shrestha
- Department of Biophysics and Cell Biology, Medical and Health Science Center, University of Debrecen, Nagyerdei krt 98, Debrecen 4032, Hungary
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van den Elsen PJ. Expression regulation of major histocompatibility complex class I and class II encoding genes. Front Immunol 2011; 2:48. [PMID: 22566838 PMCID: PMC3342053 DOI: 10.3389/fimmu.2011.00048] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 09/14/2011] [Indexed: 12/26/2022] Open
Abstract
Major histocompatibility complex (MHC)-I and MHC-II molecules play an essential role in the immune response to pathogens by virtue of their ability to present peptides to CD8+ and CD4+ T cells, respectively. Given this critical role, MHC-I and MHC-II genes are regulated in a tight fashion at the transcriptional level by a variety of transcription factors that interact with conserved cis-acting regulatory promoter elements. In addition to the activities of these regulatory factors, modification of chromatin also plays an essential role in the efficient transcription of these genes to meet with local requirement for an effective immune response. The focus of this review is on the transcription factors that interact with conserved cis-acting promoter elements and the epigenetic mechanisms that modulate induced and constitutive expression of these MHC genes.
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Affiliation(s)
- Peter J van den Elsen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center Leiden, Netherlands.
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Kämper N, Franken S, Temme S, Koch S, Bieber T, Koch N. γ-Interferon-regulated chaperone governs human lymphocyte antigen class II expression. FASEB J 2011; 26:104-16. [PMID: 21940994 DOI: 10.1096/fj.11-189670] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Antigen presentation by human lymphocyte antigen (HLA) class II peptide receptors alerts the immune system to infections. In antigen-presenting cells (APCs), HLA class II, HLA-DM, and associated invariant chain-encoding genes are exclusively regulated by the interferon γ (IFNγ)-inducible class II transactivator (CIITA). Control of CIITA expression could therefore govern expression of class II peptide receptors in the diverse group of APCs. We discovered that elevation of the HLA class III region encoded B-associated transcript 3 (BAT3) increases and depletion of BAT3 decreases expression of HLA class II, HLA-DM, and invariant chain. IFNγ strongly elevates BAT3 transcription in various tumor cell lines and in primary macrophages. BAT3 chaperones the simultaneously IFNγ-induced CIITA. Following IFNγ-treatment, both CIITA and BAT3 translocate from the cytosol to the nucleus. The nuclear import of CIITA mediated by IFNγ controls activation of HLA class II genes. BAT3 is a novel key regulator of components of the HLA class II processing pathway. We present a mechanism explaining how parallel IFNγ-mediated regulation of CIITA and of its chaperone BAT3 controls the level of components of the HLA class II processing pathway.
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Affiliation(s)
- Nadine Kämper
- Institute of Genetics, University of Bonn, Bonn, Germany
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Bhat KP, Greer SF. Proteolytic and non-proteolytic roles of ubiquitin and the ubiquitin proteasome system in transcriptional regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2010; 1809:150-5. [PMID: 21184853 DOI: 10.1016/j.bbagrm.2010.11.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Revised: 11/29/2010] [Accepted: 11/30/2010] [Indexed: 01/15/2023]
Abstract
The ubiquitin proteasome system (UPS) regulates perhaps the most intriguing balance in all of biology: how cells control protein function and malfunction in order to regulate, and eventually eliminate, the old and error prone while simultaneously synthesizing and orchestrating the new. In light of the growing notion that ubiquitination and the 26S proteasome are central to a multiplicity of diverse cellular functions, we discuss here the proteolytic and non-proteolytic roles of the UPS in regulating pathways ultimately involved in protein synthesis and activity including roles in epigenetics, transcription, and post-translational modifications. This article is part of a Special Issue entitled The 26S Proteasome: When degradation is just not enough!
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Affiliation(s)
- Kavita P Bhat
- Division of Cellular and Molecular Biology and Phsyiclogy, Department of Biology, Georgia State University, Atlanta, GA 30302, USA
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