1
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The Dilemma of HSV-1 Oncolytic Virus Delivery: The Method Choice and Hurdles. Int J Mol Sci 2023; 24:ijms24043681. [PMID: 36835091 PMCID: PMC9962028 DOI: 10.3390/ijms24043681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/03/2023] [Accepted: 02/08/2023] [Indexed: 02/15/2023] Open
Abstract
Oncolytic viruses (OVs) have emerged as effective gene therapy and immunotherapy drugs. As an important gene delivery platform, the integration of exogenous genes into OVs has become a novel path for the advancement of OV therapy, while the herpes simplex virus type 1 (HSV-1) is the most commonly used. However, the current mode of administration of HSV-1 oncolytic virus is mainly based on the tumor in situ injection, which limits the application of such OV drugs to a certain extent. Intravenous administration offers a solution to the systemic distribution of OV drugs but is ambiguous in terms of efficacy and safety. The main reason is the synergistic role of innate and adaptive immunity of the immune system in the response against the HSV-1 oncolytic virus, which is rapidly cleared by the body's immune system before it reaches the tumor, a process that is accompanied by side effects. This article reviews different administration methods of HSV-1 oncolytic virus in the process of tumor treatment, especially the research progress in intravenous administration. It also discusses immune constraints and solutions of intravenous administration with the intent to provide new insights into HSV-1 delivery for OV therapy.
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2
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Targeting immunoproteasome in neurodegeneration: A glance to the future. Pharmacol Ther 2023; 241:108329. [PMID: 36526014 DOI: 10.1016/j.pharmthera.2022.108329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022]
Abstract
The immunoproteasome is a specialized form of proteasome equipped with modified catalytic subunits that was initially discovered to play a pivotal role in MHC class I antigen processing and immune system modulation. However, over the last years, this proteolytic complex has been uncovered to serve additional functions unrelated to antigen presentation. Accordingly, it has been proposed that immunoproteasome synergizes with canonical proteasome in different cell types of the nervous system, regulating neurotransmission, metabolic pathways and adaptation of the cells to redox or inflammatory insults. Hence, studying the alterations of immunoproteasome expression and activity is gaining research interest to define the dynamics of neuroinflammation as well as the early and late molecular events that are likely involved in the pathogenesis of a variety of neurological disorders. Furthermore, these novel functions foster the perspective of immunoproteasome as a potential therapeutic target for neurodegeneration. In this review, we provide a brain and retina-wide overview, trying to correlate present knowledge on structure-function relationships of immunoproteasome with the variety of observed neuro-modulatory functions.
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3
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Functional Differences between Proteasome Subtypes. Cells 2022; 11:cells11030421. [PMID: 35159231 PMCID: PMC8834425 DOI: 10.3390/cells11030421] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/11/2022] [Accepted: 01/14/2022] [Indexed: 12/30/2022] Open
Abstract
Four proteasome subtypes are commonly present in mammalian tissues: standard proteasomes, which contain the standard catalytic subunits β1, β2 and β5; immunoproteasomes containing the immuno-subunits β1i, β2i and β5i; and two intermediate proteasomes, containing a mix of standard and immuno-subunits. Recent studies revealed the expression of two tissue-specific proteasome subtypes in cortical thymic epithelial cells and in testes: thymoproteasomes and spermatoproteasomes. In this review, we describe the mechanisms that enable the ATP- and ubiquitin-dependent as well as the ATP- and ubiquitin-independent degradation of proteins by the proteasome. We focus on understanding the role of the different proteasome subtypes in maintaining protein homeostasis in normal physiological conditions through the ATP- and ubiquitin-dependent degradation of proteins. Additionally, we discuss the role of each proteasome subtype in the ATP- and ubiquitin-independent degradation of disordered proteins. We also discuss the role of the proteasome in the generation of peptides presented by MHC class I molecules and the implication of having different proteasome subtypes for the peptide repertoire presented at the cell surface. Finally, we discuss the role of the immunoproteasome in immune cells and its modulation as a potential therapy for autoimmune diseases.
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4
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The Function of Immunoproteasomes-An Immunologists' Perspective. Cells 2021; 10:cells10123360. [PMID: 34943869 PMCID: PMC8699091 DOI: 10.3390/cells10123360] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/23/2021] [Accepted: 11/25/2021] [Indexed: 01/02/2023] Open
Abstract
Proteasomes are responsible for intracellular proteolysis and play an important role in cellular protein homeostasis. Cells of the immune system assemble a specialized form of proteasomes, known as immunoproteasomes, in which the constitutive catalytic sites are replaced for cytokine-inducible homologues. While immunoproteasomes may fulfill all standard proteasome’ functions, they seem specially adapted for a role in MHC class I antigen processing and CD8+ T-cell activation. In this way, they may contribute to CD8+ T-cell-mediated control of intracellular infections, but also to the immunopathogenesis of autoimmune diseases. Starting at the discovery of its catalytic subunits in the genome, here, we review the observations shaping our current understanding of immunoproteasome function, and the consequential novel opportunities for immune intervention.
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5
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Mihalovits LM, Ferenczy GG, Keserű GM. Mechanistic and thermodynamic characterization of oxathiazolones as potent and selective covalent immunoproteasome inhibitors. Comput Struct Biotechnol J 2021; 19:4486-4496. [PMID: 34471494 PMCID: PMC8379283 DOI: 10.1016/j.csbj.2021.08.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 08/06/2021] [Accepted: 08/06/2021] [Indexed: 01/20/2023] Open
Abstract
The ubiquitin–proteasome system is responsible for the degradation of proteins and plays a critical role in key cellular processes. While the constitutive proteasome (cPS) is expressed in all eukaryotic cells, the immunoproteasome (iPS) is primarily induced during disease processes, and its inhibition is beneficial in the treatment of cancer, autoimmune disorders and neurodegenerative diseases. Oxathiazolones were reported to selectively inhibit iPS over cPS, and the inhibitory activity of several oxathiazolones against iPS was experimentally determined. However, the detailed mechanism of the chemical reaction leading to irreversible iPS inhibition and the key selectivity drivers are unknown, and separate characterization of the noncovalent and covalent inhibition steps is not available for several compounds. Here, we investigate the chemical reaction between oxathiazolones and the Thr1 residue of iPS by quantum mechanics/molecular mechanics (QM/MM) simulations to establish a plausible reaction mechanism and to determine the rate-determining step of covalent complex formation. The modelled binding mode and reaction mechanism are in line with the selective inhibition of iPS versus cPS by oxathiazolones. The kinact value of several ligands was estimated by constructing the potential of mean force of the rate-determining step by QM/MM simulations coupled with umbrella sampling. The equilibrium constant Ki of the noncovalent complex formation was evaluated by classical force field-based thermodynamic integration. The calculated Ki and kinact values made it possible to analyse the contribution of the noncovalent and covalent steps to the overall inhibitory activity. Compounds with similar intrinsic reactivities exhibit varying selectivities for iPS versus cPS owing to subtle differences in the binding modes that slightly affect Ki, the noncovalent affinity, and importantly alter kinact, the covalent reactivity of the bound compounds. A detailed understanding of the inhibitory mechanism of oxathiazolones is useful in designing iPS selective inhibitors with improved drug-like properties.
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Affiliation(s)
- Levente M Mihalovits
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Magyar tudósok körútja 2, Budapest 1117, Hungary
| | - György G Ferenczy
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Magyar tudósok körútja 2, Budapest 1117, Hungary
| | - György M Keserű
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Magyar tudósok körútja 2, Budapest 1117, Hungary
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6
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A Nut for Every Bolt: Subunit-Selective Inhibitors of the Immunoproteasome and Their Therapeutic Potential. Cells 2021; 10:cells10081929. [PMID: 34440698 PMCID: PMC8394499 DOI: 10.3390/cells10081929] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/21/2021] [Accepted: 07/26/2021] [Indexed: 12/15/2022] Open
Abstract
At the heart of the ubiquitin-proteasome system, the 20S proteasome core particle (CP) breaks down the majority of intracellular proteins tagged for destruction. Thereby, the CP controls many cellular processes including cell cycle progression and cell signalling. Inhibitors of the CP can suppress these essential biological pathways, resulting in cytotoxicity, an effect that is beneficial for the treatment of certain blood cancer patients. During the last decade, several preclinical studies demonstrated that selective inhibition of the immunoproteasome (iCP), one of several CP variants in mammals, suppresses autoimmune diseases without inducing toxic side effects. These promising findings led to the identification of natural and synthetic iCP inhibitors with distinct chemical structures, varying potency and subunit selectivity. This review presents the most prominent iCP inhibitors with respect to possible scientific and medicinal applications, and discloses recent trends towards pan-immunoproteasome reactive inhibitors that cumulated in phase II clinical trials of the lead compound KZR-616 for chronic inflammations.
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7
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Immunoproteasome Function in Normal and Malignant Hematopoiesis. Cells 2021; 10:cells10071577. [PMID: 34206607 PMCID: PMC8305381 DOI: 10.3390/cells10071577] [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: 04/21/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 12/19/2022] Open
Abstract
The ubiquitin-proteasome system (UPS) is a central part of protein homeostasis, degrading not only misfolded or oxidized proteins but also proteins with essential functions. The fact that a healthy hematopoietic system relies on the regulation of protein homeostasis and that alterations in the UPS can lead to malignant transformation makes the UPS an attractive therapeutic target for the treatment of hematologic malignancies. Herein, inhibitors of the proteasome, the last and most important component of the UPS enzymatic cascade, have been approved for the treatment of these malignancies. However, their use has been associated with side effects, drug resistance, and relapse. Inhibitors of the immunoproteasome, a proteasomal variant constitutively expressed in the cells of hematopoietic origin, could potentially overcome the encountered problems of non-selective proteasome inhibition. Immunoproteasome inhibitors have demonstrated their efficacy and safety against inflammatory and autoimmune diseases, even though their development for the treatment of hematologic malignancies is still in the early phases. Various immunoproteasome inhibitors have shown promising preliminary results in pre-clinical studies, and one inhibitor is currently being investigated in clinical trials for the treatment of multiple myeloma. Here, we will review data on immunoproteasome function and inhibition in hematopoietic cells and hematologic cancers.
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8
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Leister H, Luu M, Staudenraus D, Lopez Krol A, Mollenkopf HJ, Sharma A, Schmerer N, Schulte LN, Bertrams W, Schmeck B, Bosmann M, Steinhoff U, Visekruna A. Pro- and Antitumorigenic Capacity of Immunoproteasomes in Shaping the Tumor Microenvironment. Cancer Immunol Res 2021; 9:682-692. [PMID: 33707310 DOI: 10.1158/2326-6066.cir-20-0492] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 12/14/2020] [Accepted: 03/09/2021] [Indexed: 12/13/2022]
Abstract
Apart from the constitutive proteasome, the immunoproteasome that comprises the three proteolytic subunits LMP2, MECL-1, and LMP7 is expressed in most immune cells. In this study, we describe opposing roles for immunoproteasomes in regulating the tumor microenvironment (TME). During chronic inflammation, immunoproteasomes modulated the expression of protumorigenic cytokines and chemokines and enhanced infiltration of innate immune cells, thus triggering the onset of colitis-associated carcinogenesis (CAC) in wild-type mice. Consequently, immunoproteasome-deficient animals (LMP2/MECL-1/LMP7-null mice) were almost completely resistant to CAC development. In patients with ulcerative colitis with high risk for CAC, immunoproteasome-induced protumorigenic mediators were upregulated. In melanoma tumors, the role of immunoproteasomes is relatively unknown. We found that high expression of immunoproteasomes in human melanoma was associated with better prognosis. Similarly, our data revealed that the immunoproteasome has antitumorigenic activity in a mouse model of melanoma. The antitumor immunity against melanoma was compromised in immunoproteasome-deficient mice because of the impaired activity of CD8+ CTLs, CD4+ Th1 cells, and antigen-presenting cells. These findings show that immunoproteasomes may exert opposing roles with either pro- or antitumoral properties in a context-dependent manner.
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Affiliation(s)
- Hanna Leister
- Institute for Medical Microbiology and Hygiene, Philipps-University Marburg, Marburg, Germany
| | - Maik Luu
- Institute for Medical Microbiology and Hygiene, Philipps-University Marburg, Marburg, Germany
| | - Daniel Staudenraus
- Institute for Medical Microbiology and Hygiene, Philipps-University Marburg, Marburg, Germany
| | - Aleksandra Lopez Krol
- Institute for Medical Microbiology and Hygiene, Philipps-University Marburg, Marburg, Germany
| | - Hans-Joachim Mollenkopf
- Max Planck Institute for Infection Biology, Core Facility Microarray/Genomics, Berlin, Germany
| | - Arjun Sharma
- Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts.,Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Nils Schmerer
- Institute for Lung Research, UGMLC, Philipps-University Marburg, Marburg, Germany.,German Center for Lung Research (DZL), Philipps-University Marburg, Marburg, Germany
| | - Leon N Schulte
- Institute for Lung Research, UGMLC, Philipps-University Marburg, Marburg, Germany.,German Center for Lung Research (DZL), Philipps-University Marburg, Marburg, Germany
| | - Wilhelm Bertrams
- Institute for Lung Research, UGMLC, Philipps-University Marburg, Marburg, Germany.,German Center for Lung Research (DZL), Philipps-University Marburg, Marburg, Germany
| | - Bernd Schmeck
- Institute for Lung Research, UGMLC, Philipps-University Marburg, Marburg, Germany.,German Center for Lung Research (DZL), Philipps-University Marburg, Marburg, Germany
| | - Markus Bosmann
- Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, Massachusetts.,Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg-University, Mainz, Germany
| | - Ulrich Steinhoff
- Institute for Medical Microbiology and Hygiene, Philipps-University Marburg, Marburg, Germany
| | - Alexander Visekruna
- Institute for Medical Microbiology and Hygiene, Philipps-University Marburg, Marburg, Germany.
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9
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Wang Y, Yan K, Lin J, Liu Y, Wang J, Li X, Li X, Hua Z, Zheng Z, Shi J, Sun S, Bi J. CD8+ T Cell Co-Expressed Genes Correlate With Clinical Phenotype and Microenvironments of Urothelial Cancer. Front Oncol 2020; 10:553399. [PMID: 33330025 PMCID: PMC7713665 DOI: 10.3389/fonc.2020.553399] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 10/20/2020] [Indexed: 01/05/2023] Open
Abstract
Purpose To identify immune-related co-expressed genes that promote CD8+ T cell infiltration in bladder cancer, and to explore the interactions among relevant genes in the tumor microenvironment. Method We obtained bladder cancer gene matrix and clinical information data from TCGA, GSE32894 and GSE48075. The “estimate” package was used to calculate tumor purity and immune score. The CIBERSORT algorithm was used to assess CD8+ T cell proportions. Weighted gene co-expression network analysis was used to identify the co-expression modules with CD8+ T cell proportions and bladder tumor purity. Subsequently, we performed correlation analysis among angiogenesis factors, angiogenesis inhibitors, immune inflammatory responses, and CD8+ T cell related genes in tumor microenvironment. Results A CD8+ T cell related co-expression network was identified. Eight co-expressed genes (PSMB8, PSMB9, PSMB10, PSME2, TAP1, IRF1, FBOX6, ETV7) were identified as CD8+ T cell-related genes that promoted infiltration of CD8+ T cells, and were enriched in the MHC class I tumor antigen presentation process. The proteins level encoded by these genes (PSMB10, PSMB9, PSMB8, TAP1, IRF1, and FBXO6) were lower in the high clinical grade patients, which suggested the clinical phenotype correlation both in mRNA and protein levels. These factors negatively correlated with angiogenesis factors and positively correlated with angiogenesis inhibitors. PD-1 and PD-L1 positively correlated with these genes which suggested PD-1 expression level positively correlated with the biological process composed by these co-expression genes. In the high expression group of these genes, inflammation and immune response were more intense, and the tumor purity was lower, suggesting that these genes were immune protective factors that improved the prognosis in patients with bladder cancer. Conclusion These co-expressed genes promote high levels of infiltration of CD8+ T cells in an immunoproteasome process involved in MHC class I molecules. The mechanism might provide new pathways for treatment of patients who are insensitive to PD-1 immunotherapy due to low degrees of CD8+ T cell infiltration.
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Affiliation(s)
- Yutao Wang
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Kexin Yan
- Department of Dermatology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Jiaxing Lin
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Yang Liu
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Jianfeng Wang
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Xuejie Li
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Xinxin Li
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Zhixiong Hua
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Zhenhua Zheng
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Jianxiu Shi
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Siqing Sun
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
| | - Jianbin Bi
- Department of Urology, China Medical University, The First Hospital of China Medical University, Shenyang, China
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10
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Xin BT, Espinal C, de Bruin G, Filippov DV, van der Marel GA, Florea BI, Overkleeft HS. Two-Step Bioorthogonal Activity-Based Protein Profiling of Individual Human Proteasome Catalytic Sites. Chembiochem 2020; 21:248-255. [PMID: 31597011 DOI: 10.1002/cbic.201900551] [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: 09/05/2019] [Indexed: 12/12/2022]
Abstract
Bioorthogonal chemistry allows the selective modification of biomolecules in complex biological samples. One application of this methodology is in two-step activity-based protein profiling (ABPP), a methodology that is particularly attractive where direct ABPP using fluorescent or biotinylated probes is ineffective. Herein we describe a set of norbornene-modified, mechanism-based proteasome inhibitors aimed to be selective for each of the six catalytic sites of human constitutive proteasomes and immunoproteasomes. The probes developed for β1i, β2i, β5c, and β5i proved to be useful two-step ABPs that effectively label their developed proteasome subunits in both Raji cell extracts and living Raji cells through inverse-electron-demand Diels-Alder (iEDDA) ligation. The compound developed for β1c proved incapable of penetrating the cell membrane, but effectively labels β1c in vitro. The compound developed for β2c proved not selective, but its azide-containing analogue LU-002c proved effective in labeling of β2c via azide-alkyne click ligation chemistry both in vitro and in situ. In total, our results contribute to the growing list of proteasome activity tools to include five subunit-selective activity-based proteasome probes, four of which report on proteasome activities in living cells.
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Affiliation(s)
- Bo-Tao Xin
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Christofer Espinal
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Gerjan de Bruin
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC, Leiden, The Netherlands.,Present address, Acerta Pharma B.V., Industrielaan 63, 5349 AE, Oss, The Netherlands
| | - Dmitri V Filippov
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Gijsbert A van der Marel
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Bogdan I Florea
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Herman S Overkleeft
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
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11
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Abstract
The proteasome degrades most cellular proteins in a controlled and tightly regulated manner and thereby controls many processes, including cell cycle, transcription, signalling, trafficking and protein quality control. Proteasomal degradation is vital in all cells and organisms, and dysfunction or failure of proteasomal degradation is associated with diverse human diseases, including cancer and neurodegeneration. Target selection is an important and well-established way to control protein degradation. In addition, mounting evidence indicates that cells adjust proteasome-mediated degradation to their needs by regulating proteasome abundance through the coordinated expression of proteasome subunits and assembly chaperones. Central to the regulation of proteasome assembly is TOR complex 1 (TORC1), which is the master regulator of cell growth and stress. This Review discusses how proteasome assembly and the regulation of proteasomal degradation are integrated with cellular physiology, including the interplay between the proteasome and autophagy pathways. Understanding these mechanisms has potential implications for disease therapy, as the misregulation of proteasome function contributes to human diseases such as cancer and neurodegeneration.
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12
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Morozov AV, Karpov VL. Proteasomes and Several Aspects of Their Heterogeneity Relevant to Cancer. Front Oncol 2019; 9:761. [PMID: 31456945 PMCID: PMC6700291 DOI: 10.3389/fonc.2019.00761] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/29/2019] [Indexed: 01/19/2023] Open
Abstract
The life of every organism is dependent on the fine-tuned mechanisms of protein synthesis and breakdown. The degradation of most intracellular proteins is performed by the ubiquitin proteasome system (UPS). Proteasomes are central elements of the UPS and represent large multisubunit protein complexes directly responsible for the protein degradation. Accumulating data indicate that there is an intriguing diversity of cellular proteasomes. Different proteasome forms, containing different subunits and attached regulators have been described. In addition, proteasomes specific for a particular tissue were identified. Cancer cells are highly dependent on the proper functioning of the UPS in general, and proteasomes in particular. At the same time, the information regarding the role of different proteasome forms in cancer is limited. This review describes the functional and structural heterogeneity of proteasomes, their association with cancer as well as several established and novel proteasome-directed therapeutic strategies.
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Affiliation(s)
- Alexey V Morozov
- Laboratory of Regulation of Intracellular Proteolysis, W.A. Engelhardt Institute of Molecular Biology RAS, Moscow, Russia
| | - Vadim L Karpov
- Laboratory of Regulation of Intracellular Proteolysis, W.A. Engelhardt Institute of Molecular Biology RAS, Moscow, Russia
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13
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Pletinckx K, Vaßen S, Schlusche I, Nordhoff S, Bahrenberg G, Dunkern TR. Inhibiting the immunoproteasome's β5i catalytic activity affects human peripheral blood-derived immune cell viability. Pharmacol Res Perspect 2019; 7:e00482. [PMID: 31236277 PMCID: PMC6581949 DOI: 10.1002/prp2.482] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 04/01/2018] [Accepted: 04/05/2019] [Indexed: 01/03/2023] Open
Abstract
Small molecule inhibitors selectively targeting the immunoproteasome subunit β5i are currently being developed for the treatment of autoimmune disorders. However, patients carrying loss-of-function mutations in the gene encoding β5i (Psmb8) suffer from the proteasome-associated autoinflammatory syndromes (PRAAS) emphasizing the need to study pharmacological inhibition of immunoproteasome function in human cells. Here, we characterized the immunomodulatory potential of the selective β5i inhibitor ONX 0914 and Bortezomib, a pan-proteasome inhibitor, in human peripheral blood mononuclear cells (PBMCs). Both compounds efficiently blocked pro-inflammatory cytokine secretion in human whole blood and PBMC cultures stimulated with toll-like receptor (TLR) agonists. Furthermore, the compounds inhibited T cell cytokine production induced by recall antigen CMVpp65 or by polyclonal stimulation. The viability of PBMCs, however, was rapidly decreased in the presence of ONX 0914 and Bortezomib demonstrated by decreased residual cytosolic ATP and increased Annexin V surface binding. Interestingly, HLA-DR + monocytes were rapidly depleted from the cultures in the presence of ONX 0914 as a β5i-selective inhibitor and Bortezomib. In conclusion, the anti-inflammatory potential of β5i-selective inhibitors is correlating with a cytotoxicity increase in human PBMC subsets ex vivo. Our results provide important insights into the anti-inflammatory mechanism of action of β5i-inhibitors which currently hold the promise as a novel therapy for autoinflammatory diseases.
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14
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Zerfas BL, Trader DJ. Monitoring the Immunoproteasome in Live Cells Using an Activity-Based Peptide-Peptoid Hybrid Probe. J Am Chem Soc 2019; 141:5252-5260. [PMID: 30862160 DOI: 10.1021/jacs.8b12873] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Activity-based probes have greatly improved our understanding of the intrinsic roles and expression levels of various proteins within cells. To be useful in live cells, probes must be cell permeable and provide a read-out that can be measured without disrupting the cells or the activity of the target. Unfortunately, probes for the various forms of the proteasome that can be utilized in intact cells are limited; commercially available probes are most effectively used with purified protein or cell lysate. The proteasome, both the 26S and various isoforms of the 20S CP, is an important target with reported roles in cancer, autoimmune disorders, and neurodegenerative diseases. Here, we present the development of a selective probe for the immunoproteasome, a specialized isoform of the 20S proteasome, that becomes expressed in cells that encounter an inflammatory signal. Using a one-bead, one-compound library of small peptides, we discovered a trimer sequence efficiently cleaved by the immunoproteasome with significant selectivity over the standard proteasome. Upon conjugating this sequence to rhodamine 110 and a peptoid, we generated a probe with a considerable improvement in sensitivity compared to that of current aminomethylcoumarin-based proteasome probes. Importantly, our probe was capable of labeling immunoproteasome-expressing cells while maintaining its selectivity over other cellular proteases in live cell cultures. We anticipate this probe to find wide utility for those that wish to study the immunoproteasome's activity in a variety of cell lines and to be used as a reporter to discover small molecules that can perturb the activity of this proteasome isoform.
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Affiliation(s)
- Breanna L Zerfas
- Department of Medicinal Chemistry and Molecular Pharmacology , Purdue University , 575 West Stadium Avenue , West Lafayette , Indiana 47907 , United States
| | - Darci J Trader
- Department of Medicinal Chemistry and Molecular Pharmacology , Purdue University , 575 West Stadium Avenue , West Lafayette , Indiana 47907 , United States
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15
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Xin BT, Huber EM, de Bruin G, Heinemeyer W, Maurits E, Espinal C, Du Y, Janssens M, Weyburne ES, Kisselev AF, Florea BI, Driessen C, van der Marel GA, Groll M, Overkleeft HS. Structure-Based Design of Inhibitors Selective for Human Proteasome β2c or β2i Subunits. J Med Chem 2019; 62:1626-1642. [PMID: 30657666 PMCID: PMC6378654 DOI: 10.1021/acs.jmedchem.8b01884] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
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Subunit-selective
proteasome inhibitors are valuable tools to assess
the biological and medicinal relevance of individual proteasome active
sites. Whereas the inhibitors for the β1c, β1i, β5c,
and β5i subunits exploit the differences in the substrate-binding
channels identified by X-ray crystallography, compounds selectively
targeting β2c or β2i could not yet be rationally designed
because of the high structural similarity of these two subunits. Here,
we report the development, chemical synthesis, and biological screening
of a compound library that led to the identification of the β2c-
and β2i-selective compounds LU-002c (4; IC50 β2c: 8 nM, IC50 β2i/β2c: 40-fold)
and LU-002i (5; IC50 β2i: 220 nM, IC50 β2c/β2i: 45-fold), respectively. Co-crystal
structures with β2 humanized yeast proteasomes visualize protein–ligand
interactions crucial for subunit specificity. Altogether, organic
syntheses, activity-based protein profiling, yeast mutagenesis, and
structural biology allowed us to decipher significant differences
of β2 substrate-binding channels and to complete the set of
subunit-selective proteasome inhibitors.
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Affiliation(s)
- Bo-Tao Xin
- Gorlaeus Laboratories , Leiden Institute of Chemistry and Netherlands Proteomics Centre , Einsteinweg 55 , 2333 CC Leiden , Netherlands
| | - Eva M Huber
- Center for Integrated Protein Science at the Department Chemie, Lehrstuhl für Biochemie , Technische Universität München , 85748 Garching , Germany
| | - Gerjan de Bruin
- Gorlaeus Laboratories , Leiden Institute of Chemistry and Netherlands Proteomics Centre , Einsteinweg 55 , 2333 CC Leiden , Netherlands
| | - Wolfgang Heinemeyer
- Center for Integrated Protein Science at the Department Chemie, Lehrstuhl für Biochemie , Technische Universität München , 85748 Garching , Germany
| | - Elmer Maurits
- Gorlaeus Laboratories , Leiden Institute of Chemistry and Netherlands Proteomics Centre , Einsteinweg 55 , 2333 CC Leiden , Netherlands
| | - Christofer Espinal
- Gorlaeus Laboratories , Leiden Institute of Chemistry and Netherlands Proteomics Centre , Einsteinweg 55 , 2333 CC Leiden , Netherlands
| | - Yimeng Du
- Gorlaeus Laboratories , Leiden Institute of Chemistry and Netherlands Proteomics Centre , Einsteinweg 55 , 2333 CC Leiden , Netherlands
| | - Marissa Janssens
- Gorlaeus Laboratories , Leiden Institute of Chemistry and Netherlands Proteomics Centre , Einsteinweg 55 , 2333 CC Leiden , Netherlands
| | - Emily S Weyburne
- Department of Molecular and Systems Biology and Norris Cotton Cancer Center , Geisel School of Medicine at Dartmouth , 1 Medical Centre Drive HB7936 , Lebanon , New Hampshire 03756 , United States
| | - Alexei F Kisselev
- Department of Molecular and Systems Biology and Norris Cotton Cancer Center , Geisel School of Medicine at Dartmouth , 1 Medical Centre Drive HB7936 , Lebanon , New Hampshire 03756 , United States
| | - Bogdan I Florea
- Gorlaeus Laboratories , Leiden Institute of Chemistry and Netherlands Proteomics Centre , Einsteinweg 55 , 2333 CC Leiden , Netherlands
| | - Christoph Driessen
- Department of Hematology and Oncology , Kantonsspital St. Gallen , 9007 St. Gallen , Switzerland
| | - Gijsbert A van der Marel
- Gorlaeus Laboratories , Leiden Institute of Chemistry and Netherlands Proteomics Centre , Einsteinweg 55 , 2333 CC Leiden , Netherlands
| | - Michael Groll
- Center for Integrated Protein Science at the Department Chemie, Lehrstuhl für Biochemie , Technische Universität München , 85748 Garching , Germany
| | - Herman S Overkleeft
- Gorlaeus Laboratories , Leiden Institute of Chemistry and Netherlands Proteomics Centre , Einsteinweg 55 , 2333 CC Leiden , Netherlands
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16
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Schmidt C, Berger T, Groettrup M, Basler M. Immunoproteasome Inhibition Impairs T and B Cell Activation by Restraining ERK Signaling and Proteostasis. Front Immunol 2018; 9:2386. [PMID: 30416500 PMCID: PMC6212513 DOI: 10.3389/fimmu.2018.02386] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 09/26/2018] [Indexed: 12/19/2022] Open
Abstract
Immunoproteasome (IP) inhibition holds potential as a novel treatment option for various immune-mediated pathologies. The IP inhibitor ONX 0914 reduced T cell cytokine secretion and Th17 polarization and showed pre-clinical efficacy in a range of autoimmune disorders, transplant-allograft rejection, virus-mediated tissue damage, and colon cancer progression. However, the molecular basis of these effects has remained largely elusive. Here, we have analyzed the effects of ONX 0914 in primary human and mouse lymphocytes. ONX 0914-treatment impaired primary T cell activation in vitro and in vivo. IP inhibition reduced ERK-phosphorylation sustainment, while leaving NF-κB and other signaling pathways unaffected. Naïve T and B cells expressed nearly exclusively immuno- or mixed proteasomes but no standard proteasomes and IP inhibition but not IP-deficiency induced mild proteostasis stress, reduced DUSP5 expression and enhanced DUSP6 protein levels due to impaired degradation. However, accumulation of DUSP6 did not cause the reduced ERK-phosphorylation in a non-redundant manner. We show that broad-spectrum proteasome inhibition and immunoproteasome inhibition have distinct effects on T cell activation at the molecular level. Notably, ONX 0914-treated T cells recovered from proteostasis stress without apoptosis induction, apparently via Nrf1-mediated up-regulation of standard proteasomes. In contrast, B cells were more susceptible to apoptosis after ONX 0914-treatment. Our data thus provide mechanistic insights how IP inhibition functionally impedes T and B cells likely accounting for its therapeutic benefits.
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Affiliation(s)
- Christian Schmidt
- Chair of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany.,Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany
| | - Thilo Berger
- Chair of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany
| | - Marcus Groettrup
- Chair of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany.,Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany.,Biotechnology Institute Thurgau at the University of Konstanz, Kreuzlingen, Switzerland
| | - Michael Basler
- Chair of Immunology, Department of Biology, University of Konstanz, Konstanz, Germany.,Konstanz Research School Chemical Biology, University of Konstanz, Konstanz, Germany.,Biotechnology Institute Thurgau at the University of Konstanz, Kreuzlingen, Switzerland
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17
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Wada H, Shimizu A, Osada T, Tanaka Y, Fukaya S, Sasaki E. Development of a novel immunoproteasome digestion assay for synthetic long peptide vaccine design. PLoS One 2018; 13:e0199249. [PMID: 29969453 PMCID: PMC6029771 DOI: 10.1371/journal.pone.0199249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 06/04/2018] [Indexed: 12/22/2022] Open
Abstract
Recently, many autologous tumor antigens have been examined for their potential use in cancer immunotherapy. However, the success of cancer vaccines in clinical trials has been limited, partly because of the limitations of using single, short peptides in most attempts. With this in mind, we aimed to develop multivalent synthetic long peptide (SLP) vaccines containing multiple cytotoxic T-lymphocyte (CTL) epitopes. However, to confirm whether a multivalent vaccine can induce an individual epitope-specific CTL, the only viable screening strategies currently available are interferon-gamma (IFN-μ enzyme-linked immunospot (ELISPOT) assays using human peripheral blood mononuclear cells, or expensive human leukocyte antigen (HLA)-expressing mice. In this report, we evaluated the use of our developed murine-20S immunoproteasome (i20S) digestion assay, and found that it could predict the results of IFN-μ ELISPOT assays. Importantly, the murine-i20S digestion assay not only predicted CTL induction, but also antitumor activity in an HLA-expressing mouse model. We conclude that the murine-i20S digestion assay is an extremely useful tool for the development of “all functional” multivalent SLP vaccines.
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MESH Headings
- Amino Acid Sequence
- Animals
- Cancer Vaccines/chemical synthesis
- Cancer Vaccines/immunology
- Cancer Vaccines/pharmacology
- Enzyme-Linked Immunospot Assay
- Epitopes, T-Lymphocyte/chemistry
- Epitopes, T-Lymphocyte/immunology
- HLA-A2 Antigen/genetics
- HLA-A2 Antigen/immunology
- Humans
- Immunoassay
- Immunotherapy, Active/methods
- Interferon-gamma/biosynthesis
- Interferon-gamma/immunology
- Lymphocyte Activation/drug effects
- Melanoma, Experimental/genetics
- Melanoma, Experimental/immunology
- Melanoma, Experimental/pathology
- Melanoma, Experimental/prevention & control
- Mice
- Mice, Transgenic
- Peptides/chemical synthesis
- Peptides/immunology
- Peptides/pharmacology
- Proteasome Endopeptidase Complex/genetics
- Proteasome Endopeptidase Complex/immunology
- T-Lymphocytes, Cytotoxic/cytology
- T-Lymphocytes, Cytotoxic/drug effects
- T-Lymphocytes, Cytotoxic/immunology
- Transgenes
- Tumor Burden/drug effects
- Vaccines, Subunit
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Affiliation(s)
- Hiroshi Wada
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co. Ltd., Tsukuba, Ibaraki, Japan
- * E-mail:
| | - Atsushi Shimizu
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co. Ltd., Tsukuba, Ibaraki, Japan
| | - Toshihiro Osada
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co. Ltd., Tsukuba, Ibaraki, Japan
| | - Yuki Tanaka
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co. Ltd., Tsukuba, Ibaraki, Japan
| | - Satoshi Fukaya
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co. Ltd., Tsukuba, Ibaraki, Japan
| | - Eiji Sasaki
- Discovery and Preclinical Research Division, Taiho Pharmaceutical Co. Ltd., Tsukuba, Ibaraki, Japan
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18
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Driscoll JJ, Brailey M. Emerging small molecule approaches to enhance the antimyeloma benefit of proteasome inhibitors. Cancer Metastasis Rev 2018; 36:585-598. [PMID: 29052093 DOI: 10.1007/s10555-017-9698-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Multiple myeloma (MM) is a clonal plasma cell malignancy which, despite recent treatment advances, remains incurable in the vast majority of the over 118,000 patients in the USA afflicted with this disease. Treatment of MM has dramatically improved in the past decade with the introduction of new drugs into therapeutic strategies in both the frontline and relapse settings that has led to a significant improvement in the median overall survival (OS). These drugs have been incorporated into clinical guidelines and transformed the treatment approach to MM. Numerous classes of antimyeloma agents, i.e., alkylators, steroids, proteasome inhibitors, immunomodulatory agents, deactylase inhibitors, and monoclonal antibodies, are now FDA-approved and can be combined in doublet or triplet regimens. Moreover, many patients do not respond to therapy and those that do eventually relapse. Emerging therapies that may overcome drug resistance and improve MM treatment include that inhibit regulatory and Ub-processing components of the proteasome, a specialized variant of the proteasome known as the immunoproteasome, proteolysis-targeting chimeric molecules (PROTACS and Degronomids). Emerging strategies also include accessory plasmacytoid dendritic cells (pDCs), vaccines, checkpoint inhibitors, and chimeric antigen receptor-engineered T (CAR-T) cells. Advances in understanding proteasome and plasma cell biology may allow for earlier treatment of MM patients using rationally informed combination therapies with curative potential.
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Affiliation(s)
- James J Driscoll
- Department of Internal Medicine, Division of Hematology and Oncology, Cincinnati, OH, 45267, USA. .,University of Cincinnati Cancer Institute, Cincinnati, OH, 45267, USA.
| | - Magen Brailey
- University of Cincinnati Cancer Institute, Cincinnati, OH, 45267, USA.,McMicken College of Arts and Sciences, Biology, Cincinnati, OH, USA
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19
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The 20S immunoproteasome and constitutive proteasome bind with the same affinity to PA28αβ and equally degrade FAT10. Mol Immunol 2017; 113:22-30. [PMID: 29208314 DOI: 10.1016/j.molimm.2017.11.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/27/2017] [Accepted: 11/28/2017] [Indexed: 11/22/2022]
Abstract
The 20S immunoproteasome (IP) is an interferon(IFN)-γ - and tumor necrosis factor (TNF) -inducible variant of the 20S constitutive proteasome (CP) in which all its peptidolytically active subunits β1, β2, and β5 are replaced by their cytokine inducible homologues β1i (LMP2), β2i (MECL-1), and β5i (LMP7). These subunit replacements alter the cleavage specificity of the proteasome and the spectrum of proteasome-generated peptide ligands of MHC class I molecules. In addition to antigen processing, the IP has recently been shown to serve unique functions in the generation of pro-inflammatory T helper cell subtypes and cytokines as well as in the pathogenesis of autoimmune diseases, but the mechanistic involvement of the IP in these processes has remained elusive. In this study we investigated whether the IP differs from the CP in the interaction with two IFN-γ/TNF inducible factors: the 11S proteasome regulator PA28αβ and the ubiquitin-like modifier FAT10 (ubiquitin D). Using thermophoresis, we determined the affinity of PA28αβ for the CP and IP to be 12.2nM +/- 2.8nM and 15.3nM +/- 2.7nM, respectively, which is virtually identical. Also the activation of the peptidolytic activities of the IP and CP by PA28αβ did not differ. For FAT10 we determined the degradation kinetics in cycloheximide chase experiments in cells expressing almost exclusively IP or CP as well as in IFN-γ stimulated and unstimulated cells and found no differences between the degradation rates. Taken together, we conclude that neither differences in the binding strength to, nor activation by PA28αβ, nor a difference in the rate of FAT10-mediated degradation can account for distinct functional capabilities of the IP as compared to the CP.
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20
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Huber EM, Groll M. The Mammalian Proteasome Activator PA28 Forms an Asymmetric α 4β 3 Complex. Structure 2017; 25:1473-1480.e3. [PMID: 28867616 DOI: 10.1016/j.str.2017.07.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Revised: 07/17/2017] [Accepted: 07/26/2017] [Indexed: 10/19/2022]
Abstract
The heptameric proteasome activator (PA) 28αβ is known to modulate class I antigen processing by docking onto 20S proteasome core particles (CPs). The exact stoichiometry and arrangement of its α and β subunits, however, is still controversial. Here we analyzed murine PA28 complexes regarding structure and assembly. Strikingly, PA28α, PA28β, and PA28αβ preparations form heptamers, but solely PA28α and PA28αβ associate with CPs. Co-expression of α and β yields one unique PA28αβ species with an unchangeable subunit composition. Structural data on PA28α, PA28β, and PA28αβ up to 2.9 Å resolution reveal a PA28α4β3 complex with an alternating subunit arrangement and a single α-α interface. Differential scanning fluorimetry experiments and activity assays classify PA28α4β3 as most stable and most active, indicating that this assembly might represent the physiologically relevant species. Together, our data resolve subunit composition and arrangement of PA28αβ and clarify how an asymmetric heptamer can be assembled from two highly homologous subunits.
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Affiliation(s)
- Eva M Huber
- Center for Integrated Protein Science, Department Chemie, Lehrstuhl für Biochemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany.
| | - Michael Groll
- Center for Integrated Protein Science, Department Chemie, Lehrstuhl für Biochemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany.
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21
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Morris EP, da Fonseca PCA. High-resolution cryo-EM proteasome structures in drug development. Acta Crystallogr D Struct Biol 2017; 73:522-533. [PMID: 28580914 PMCID: PMC5458494 DOI: 10.1107/s2059798317007021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/10/2017] [Indexed: 11/16/2022] Open
Abstract
With the recent advances in biological structural electron microscopy (EM), protein structures can now be obtained by cryo-EM and single-particle analysis at resolutions that used to be achievable only by crystallographic or NMR methods. We have explored their application to study protein-ligand interactions using the human 20S proteasome, a well established target for cancer therapy that is also being investigated as a target for an increasing range of other medical conditions. The map of a ligand-bound human 20S proteasome served as a proof of principle that cryo-EM is emerging as a realistic approach for more general structural studies of protein-ligand interactions, with the potential benefits of extending such studies to complexes that are unfavourable to other methods and allowing structure determination under conditions that are closer to physiological, preserving ligand specificity towards closely related binding sites. Subsequently, the cryo-EM structure of the Plasmodium falciparum 20S proteasome, with a new prototype specific inhibitor bound, revealed the molecular basis for the ligand specificity towards the parasite complex, which provides a framework to guide the development of highly needed new-generation antimalarials. Here, the cryo-EM analysis of the ligand-bound human and P. falciparum 20S proteasomes is reviewed, and a complete description of the methods used for structure determination is provided, including the strategy to overcome the bias orientation of the human 20S proteasome on electron-microscope grids and details of the icr3d software used for three-dimensional reconstruction.
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Affiliation(s)
- Edward P. Morris
- Division of Structural Biology, The Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, England
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22
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Bardag-Gorce F, Hoft R, Meepe I, Garcia J, Tiger K, Wood A, Laporte A, Pan D, Makalinao A, Niihara R, Oliva J, Florentino A, Gorce AM, Stark J, Cortez D, French SW, Niihara Y. Proteasomes in corneal epithelial cells and cultured autologous oral mucosal epithelial cell sheet (CAOMECS) graft used for the ocular surface regeneration. Ocul Surf 2017; 15:749-758. [PMID: 28528957 DOI: 10.1016/j.jtos.2017.05.010] [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: 03/15/2017] [Revised: 04/21/2017] [Accepted: 05/17/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE This study focuses on characterizing proteasomes in corneal epithelial cells (CEC) and in cultured autologous oral mucosal epithelial cell sheets (CAOMECS) used to regenerate the ocular surface. METHODS Limbal stem cell deficiency (LSCD) was surgically induced in rabbit corneas. CAOMECS was engineered and grafted onto corneas with LSCD to regenerate the ocular surface. RESULTS LSCD caused an increase in inflammatory cells in the ocular surface, an increase in the formation of immunoproteasomes (IPR), and a decrease in the formation of constitutive proteasome (CPR). Specifically, LSCD-diseased CEC (D-CEC) showed a decrease in the CPR chymotrypsin-like, trypsin-like and caspase-like activities, while healthy CEC (H-CEC) and CAOMECS showed higher activities. Quantitative analysis of IPR inducible subunit (B5i, B2i, and B1i) were performed and compared to CPR subunit (B5, B2, and B1) levels. Results showed that ratios B5i/B5, B2i/B2 and B1i/B1 were higher in D-CEC, indicating that D-CEC had approximately a two-fold increase in the amount of IPR compared to CAOMECS and H-CEC. Histological analysis demonstrated that CAOMECS-grafted corneas had a re-epithelialized surface, positive staining for CPR subunits, and weak staining for IPR subunits. In addition, digital quantitative measurement of fluorescent intensity showed that the CPR B5 subunit was significantly more expressed in CAOMECS-grafted corneas compared to non-grafted corneas with LSCD. CONCLUSION CAOMECS grafting successfully replaced the D-CEC with oral mucosal epithelial cells with higher levels of CPR. The increase in constitutive proteasome expression is possibly responsible for the recovery and improvement in CAOMECS-grafted corneas.
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Affiliation(s)
- Fawzia Bardag-Gorce
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA.
| | - Richard Hoft
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Imara Meepe
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Julio Garcia
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Kumar Tiger
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Andrew Wood
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Amanda Laporte
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Derek Pan
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Andrew Makalinao
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Robert Niihara
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Joan Oliva
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Arjie Florentino
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Amber M Gorce
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Jeremy Stark
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Daileen Cortez
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Samuel W French
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
| | - Yutaka Niihara
- Los Angeles Biomedical Research Institute (LA BioMed) at Harbor-UCLA Medical Center, Torrance, CA 90502, USA
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23
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Zhang J, Liu H, Wei B. Immune response of T cells during herpes simplex virus type 1 (HSV-1) infection. J Zhejiang Univ Sci B 2017; 18:277-288. [PMID: 28378566 PMCID: PMC5394093 DOI: 10.1631/jzus.b1600460] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/07/2017] [Indexed: 12/14/2022]
Abstract
Herpes simplex virus type 1 (HSV-1), a neurotropic member of the alphaherpes virus family, is among the most prevalent and successful human pathogens. HSV-1 can cause serious diseases at every stage of life including fatal disseminated disease in newborns, cold sores, eye disease, and fatal encephalitis in adults. HSV-1 infection can trigger rapid immune responses, and efficient inhibition and clearance of HSV-1 infection rely on both the innate and adaptive immune responses of the host. Multiple strategies have been used to restrict host innate immune responses by HSV-1 to facilitate its infection in host cells. The adaptive immunity of the host plays an important role in inhibiting HSV-1 infections. The activation and regulation of T cells are the important aspects of the adaptive immunity. They play a crucial role in host-mediated immunity and are important for clearing HSV-1. In this review, we examine the findings on T cell immune responses during HSV-1 infection, which hold promise in the design of new vaccine candidates for HSV-1.
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24
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Rock KL, Reits E, Neefjes J. Present Yourself! By MHC Class I and MHC Class II Molecules. Trends Immunol 2016; 37:724-737. [PMID: 27614798 DOI: 10.1016/j.it.2016.08.010] [Citation(s) in RCA: 454] [Impact Index Per Article: 56.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 08/09/2016] [Accepted: 08/15/2016] [Indexed: 12/01/2022]
Abstract
Since the discovery of MHC molecules, it has taken 40 years to arrive at a coherent picture of how MHC class I and MHC class II molecules really work. This is a story of the proteases and MHC-like chaperones that support the MHC class I and II molecules in presenting peptides to the immune system. We now understand that the MHC system shapes both the repertoire of presented peptides and the subsequent T cell response, with important implications ranging from transplant rejection to tumor immunotherapies. Here we present an illustrated review of the ins and outs of MHC class I and MHC class II antigen presentation.
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Affiliation(s)
- Kenneth L Rock
- Department of Pathology, UMass Medical School, Worcester, MA, USA
| | - Eric Reits
- Department of Cell Biology and Histology, Amsterdam Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Jacques Neefjes
- Department of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Chemical Immunology, Leiden University Medical Center, Leiden, The Netherlands.
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25
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Xin BT, de Bruin G, Huber EM, Besse A, Florea BI, Filippov DV, van der Marel GA, Kisselev AF, van der Stelt M, Driessen C, Groll M, Overkleeft HS. Structure-Based Design of β5c Selective Inhibitors of Human Constitutive Proteasomes. J Med Chem 2016; 59:7177-87. [PMID: 27438186 DOI: 10.1021/acs.jmedchem.6b00705] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This work reports the development of highly potent and selective inhibitors of the β5c catalytic activity of human constitutive proteasomes. The work describes the design principles, large hydrophobic P3 residue and small hydrophobic P1 residue, that led to the synthesis of a panel of peptide epoxyketones; their evaluation and the selection of the most promising compounds for further analyses. Structure-activity relationships detail how in a logical order the β1c/i, β2c/i, and β5i activities became resistant to inhibition as compounds were diversified stepwise. The most effective compounds were obtained as a mixture of cis- and trans-biscyclohexyl isomers, and enantioselective synthesis resolved this issue. Studies on yeast proteasome structures complexed with some of the compounds provide a rationale for the potency and specificity. Substitution of the N-terminus in the most potent compound for a more soluble equivalent led to a cell-permeable molecule that selectively and efficiently blocks β5c in cells expressing both constitutive proteasomes and immunoproteasomes.
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Affiliation(s)
- Bo-Tao Xin
- Gorlaeus Laboratories, Leiden Institute of Chemistry , Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Gerjan de Bruin
- Gorlaeus Laboratories, Leiden Institute of Chemistry , Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Eva M Huber
- Center for Integrated Protein Science at the Department Chemie, Lehrstuhl für Biochemie, Technische Universität München , 85748 Garching, Germany
| | - Andrej Besse
- Department of Hematology and Oncology, Kantonsspital St. Gallen , 9007 St. Gallen, Switzerland
| | - Bogdan I Florea
- Gorlaeus Laboratories, Leiden Institute of Chemistry , Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Dmitri V Filippov
- Gorlaeus Laboratories, Leiden Institute of Chemistry , Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Gijsbert A van der Marel
- Gorlaeus Laboratories, Leiden Institute of Chemistry , Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Alexei F Kisselev
- Department of Pharmacology and Toxicology and Norris Cotton Cancer Center, Geisel Cancer School of Medicine at Dartmouth , 1 Medical Center Drive HB7936, Lebanon, New Hampshire 03756, United States
| | - Mario van der Stelt
- Gorlaeus Laboratories, Leiden Institute of Chemistry , Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Christoph Driessen
- Department of Hematology and Oncology, Kantonsspital St. Gallen , 9007 St. Gallen, Switzerland
| | - Michael Groll
- Center for Integrated Protein Science at the Department Chemie, Lehrstuhl für Biochemie, Technische Universität München , 85748 Garching, Germany
| | - Herman S Overkleeft
- Gorlaeus Laboratories, Leiden Institute of Chemistry , Einsteinweg 55, 2333 CC Leiden, The Netherlands
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26
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Johnston-Carey HK, Pomatto LCD, Davies KJA. The Immunoproteasome in oxidative stress, aging, and disease. Crit Rev Biochem Mol Biol 2016; 51:268-81. [PMID: 27098648 DOI: 10.3109/10409238.2016.1172554] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The Immunoproteasome has traditionally been viewed primarily for its role in peptide production for antigen presentation by the major histocompatibility complex, which is critical for immunity. However, recent research has shown that the Immunoproteasome is also very important for the clearance of oxidatively damaged proteins in homeostasis, and especially during stress and disease. The importance of the Immunoproteasome in protein degradation has become more evident as diseases characterized by protein aggregates have also been linked to deficiencies of the Immunoproteasome. Additionally, there are now diseases defined by mutations or polymorphisms within Immunoproteasome-specific subunit genes, further suggesting its crucial role in cytokine signaling and protein homeostasis (or "proteostasis"). The purpose of this review is to highlight our growing understanding of the importance of the Immunoproteasome in the management of protein quality control, and the detrimental impact of its dysregulation during disease and aging.
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Affiliation(s)
- Helen K Johnston-Carey
- a Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center , The University of Southern California , Los Angeles , CA , USA
| | - Laura C D Pomatto
- a Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center , The University of Southern California , Los Angeles , CA , USA
| | - Kelvin J A Davies
- a Leonard Davis School of Gerontology of the Ethel Percy Andrus Gerontology Center , The University of Southern California , Los Angeles , CA , USA ;,b Division of Molecular & Computational Biology, Department of Biological Sciences, Dornsife College of Letters, Arts, & Sciences , Los Angeles , CA , USA
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Beck P, Reboud-Ravaux M, Groll M. Identifizierung eines Sulfonamids als β1/β2-spezifischer Proteasomligand durch kristallographisches Screening. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201505054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abstract
Cellular proteostasis is a highly dynamic process and is primarily carried out by the degradation tools of ubiquitin-proteasome system (UPS). Abnormalities in UPS function result in the accumulation of damaged or misfolded proteins which can form intra- and extracellular aggregated proteinaceous deposits leading to cellular dysfunction and/or death. Deposition of abnormal protein aggregates and the cellular inability to clear them have been implicated in the pathogenesis of a number of neurodegenerative disorders such as Alzheimer's and Parkinson's. Contrary to the upregulation of proteasome function in oncogenesis and the use of proteasome inhibition as a therapeutic strategy, activation of proteasome function would serve therapeutic objectives of treatment of neurodegenerative diseases. This review describes the current understanding of the role of the proteasome in neurodegenerative disorders and potential utility of proteasomal modulation therein.
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Affiliation(s)
- Geeta Rao
- Department of Pharmaceutical Sciences, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Brandon Croft
- Department of Pharmaceutical Sciences, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Chengwen Teng
- Department of Pharmaceutical Sciences, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Vibhudutta Awasthi
- Department of Pharmaceutical Sciences, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
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Beck P, Reboud-Ravaux M, Groll M. Identification of a β1/β2-specific sulfonamide proteasome ligand by crystallographic screening. Angew Chem Int Ed Engl 2015; 54:11275-8. [PMID: 26242779 DOI: 10.1002/anie.201505054] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 07/03/2015] [Indexed: 11/07/2022]
Abstract
The proteasome represents a validated drug target for the treatment of cancer, however, new types of inhibitors are required to tackle the development of resistant tumors. Current fluorescence-based screening methods suffer from low sensitivity and are limited to the detection of ligands with conventional binding profiles. In response to these drawbacks, a crystallographic screening procedure for the discovery of agents with a novel mode of action was utilized. The optimized workflow was applied to the screening of a focused set of compounds, resulting in the discovery of a β1/β2-specific sulfonamide derivative that noncovalently binds between subunits β1 and β2. The binding pocket displays significant differences in size and polarity between the immuno- and constitutive proteasome. The identified ligand thus provides valuable insights for the future structure-based design of subtype-specific proteasome inhibitors.
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Affiliation(s)
- Philipp Beck
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, 85748 Garching (Germany)
| | - Michèle Reboud-Ravaux
- Sorbonne Universités, UPMC Univ Paris 06, UMR/CNRS 8256, Case 256, 7 Quai St-Bernard, 75252 Paris Cedex 05 (France)
| | - Michael Groll
- Center for Integrated Protein Science Munich (CIPSM), Department of Chemistry, Technische Universität München, Lichtenbergstraße 4, 85748 Garching (Germany).
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Sasaki K, Takada K, Ohte Y, Kondo H, Sorimachi H, Tanaka K, Takahama Y, Murata S. Thymoproteasomes produce unique peptide motifs for positive selection of CD8(+) T cells. Nat Commun 2015; 6:7484. [PMID: 26099460 PMCID: PMC4557289 DOI: 10.1038/ncomms8484] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 05/13/2015] [Indexed: 11/09/2022] Open
Abstract
Positive selection in the thymus provides low-affinity T-cell receptor (TCR) engagement to support the development of potentially useful self-major histocompatibility complex class I (MHC-I)-restricted T cells. Optimal positive selection of CD8(+) T cells requires cortical thymic epithelial cells that express β5t-containing thymoproteasomes (tCPs). However, how tCPs govern positive selection is unclear. Here we show that the tCPs produce unique cleavage motifs in digested peptides and in MHC-I-associated peptides. Interestingly, MHC-I-associated peptides carrying these tCP-dependent motifs are enriched with low-affinity TCR ligands that efficiently induce the positive selection of functionally competent CD8(+) T cells in antigen-specific TCR-transgenic models. These results suggest that tCPs contribute to the positive selection of CD8(+) T cells by preferentially producing low-affinity TCR ligand peptides.
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Affiliation(s)
- Katsuhiro Sasaki
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Kensuke Takada
- Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima 770-8503, Japan
| | - Yuki Ohte
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Hiroyuki Kondo
- Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima 770-8503, Japan
| | - Hiroyuki Sorimachi
- Calpain Project, Department of Advanced Science for Biomolecules, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Keiji Tanaka
- Laboratory of Protein Metabolism, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Yousuke Takahama
- Division of Experimental Immunology, Institute for Genome Research, University of Tokushima, Tokushima 770-8503, Japan
| | - Shigeo Murata
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan
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Crystal Structure of the Human 20S Proteasome in Complex with Carfilzomib. Structure 2015; 23:418-24. [DOI: 10.1016/j.str.2014.11.017] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 11/05/2014] [Accepted: 11/13/2014] [Indexed: 11/21/2022]
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McCarthy MK, Weinberg JB. The immunoproteasome and viral infection: a complex regulator of inflammation. Front Microbiol 2015; 6:21. [PMID: 25688236 PMCID: PMC4310299 DOI: 10.3389/fmicb.2015.00021] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/08/2015] [Indexed: 11/13/2022] Open
Abstract
During viral infection, proper regulation of immune responses is necessary to ensure successful viral clearance with minimal host tissue damage. Proteasomes play a crucial role in the generation of antigenic peptides for presentation on MHC class I molecules, and thus activation of CD8 T cells, as well as activation of the NF-κB pathway. A specialized type of proteasome called the immunoproteasome is constitutively expressed in hematopoietic cells and induced in non-immune cells during viral infection by interferon signaling. The immunoproteasome regulates CD8 T cell responses to many viral epitopes during infection. Accumulating evidence suggests that the immunoproteasome may also contribute to regulation of proinflammatory cytokine production, activation of the NF-κB pathway, and management of oxidative stress. Many viruses have mechanisms of interfering with immunoproteasome function, including prevention of transcriptional upregulation of immunoproteasome components as well as direct interaction of viral proteins with immunoproteasome subunits. A better understanding of the role of the immunoproteasome in different cell types, tissues, and hosts has the potential to improve vaccine design and facilitate the development of effective treatment strategies for viral infections.
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Affiliation(s)
- Mary K McCarthy
- Department of Microbiology and Immunology, University of Michigan Ann Arbor, MI, USA
| | - Jason B Weinberg
- Department of Microbiology and Immunology, University of Michigan Ann Arbor, MI, USA ; Department of Pediatrics and Communicable Diseases, University of Michigan Ann Arbor, MI, USA
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Cornish Carmony K, Sharma LK, Lee DM, Park JE, Lee W, Kim KB. Elucidating the catalytic subunit composition of distinct proteasome subtypes: a crosslinking approach employing bifunctional activity-based probes. Chembiochem 2014; 16:284-92. [PMID: 25477005 DOI: 10.1002/cbic.201402491] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Indexed: 12/25/2022]
Abstract
In addition to two well-recognized proteasome subtypes-constitutive proteasomes and immunoproteasomes-mounting evidence also suggests the existence of intermediate proteasome subtypes containing unconventional mixtures of catalytic subunits. Although they appear to play unique biological roles, the lack of practical methods for detecting distinct proteasome subtypes has limited functional investigations. Here, we report the development of activity-based probes that crosslink two catalytic subunits within intact proteasome complexes. Identification of the crosslinked subunit pairs provides direct evidence of the catalytic subunit composition of proteasomes. Using these probes, we found that U266 multiple myeloma cells contain intermediate proteasomes comprising both β1i and β2, but not β1 and β2i, consistent with previous findings with other cell types. Our bifunctional probes can be utilized in functional investigations of distinct proteasome subtypes in various biological settings.
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Affiliation(s)
- Kimberly Cornish Carmony
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 South Limestone Street, Lexington, KY 40536-0596 (USA)
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Erath S, Groettrup M. No evidence for immunoproteasomes in chicken lymphoid organs and activated lymphocytes. Immunogenetics 2014; 67:51-60. [PMID: 25403261 DOI: 10.1007/s00251-014-0814-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 11/05/2014] [Indexed: 11/29/2022]
Abstract
The proteasome is the main protein-degrading machine within the cell, producing ligands for MHC class I molecules. It is a cylindrical multicatalytic protease complex, and the catalytic activity is mediated by the three subunits β1, β2, and β5 which possess caspase-, trypsin-, and chymotrypsin-like activities, respectively. By stimulation with interferon (IFN)-γ the replacement of these subunits by β1i, β2i, and β5i is induced leading to formation of immunoproteasomes with altered proteolytic and antigen processing properties. The genes coding for these immunosubunits are restricted to jawed vertebrates but have so far not been found in the genomes of birds, e.g., chicken, turkey, quail, black grouse and zebra finch. However, the chicken genome sequences are not completely assigned; therefore, we investigated the presence of immunoproteasome on protein level. 20S proteasome was purified from the chicken brain, blood, spleen, and bursa of Fabricius, followed by separation via two-dimensional (2D) gel electrophoresis. We analyzed the protein spots derived from the spleen and brain by mass spectrometry and could identify all 14 proteasomal subunits, but there were no differences detectable in the spot patterns. Moreover, we stimulated the chicken spleen cells with phorbol 12-myristate 13-acetate (PMA) and ionomycin aiming at the induction of immunoproteasome, but in spite of the induction of proliferation and IFN-γ, no evidence for immunoproteasome formation in chicken could be obtained. This result was substantiated by the finding that 20S proteasomes isolated from immune and non-immune tissues showed very similar peptidolytic activities. Taken together, our results indicate that chicken lack immunoproteasomes also on protein level.
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Affiliation(s)
- Sonja Erath
- Department of Immunology, University of Konstanz, Universitaetsstrasse 10, 78464, Konstanz, Germany
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Manasanch EE, Korde N, Zingone A, Tageja N, Fernandez de Larrea C, Bhutani M, Wu P, Roschewski M, Landgren O. The proteasome: mechanisms of biology and markers of activity and response to treatment in multiple myeloma. Leuk Lymphoma 2014; 55:1707-14. [PMID: 24261677 DOI: 10.3109/10428194.2013.828351] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Since the early 1990s, the synthesis and subsequent clinical application of small molecule inhibitors of the ubiquitin proteasome pathway (UPP) has revolutionized the treatment and prognosis of multiple myeloma. In this review, we summarize important aspects of the biology of the UPP with a focus on its structure and key upstream/downstream regulatory components. We then review current knowledge of plasma cell sensitivity to proteasome inhibition and highlight new proteasome inhibitors that have recently entered clinical development. Lastly, we address the putative role of circulating proteasomes as a novel biomarker in multiple myeloma and provide guidance for future clinical trials using proteasome inhibitors.
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Affiliation(s)
- Elisabet E Manasanch
- Multiple Myeloma Section, Metabolism Branch, National Cancer Institute, National Institutes of Health , Bethesda, MD , USA
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Ferrington DA, Gregerson DS. Immunoproteasomes: structure, function, and antigen presentation. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 109:75-112. [PMID: 22727420 DOI: 10.1016/b978-0-12-397863-9.00003-1] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Immunoproteasomes contain replacements for the three catalytic subunits of standard proteasomes. In most cells, oxidative stress and proinflammatory cytokines are stimuli that lead to elevated production of immunoproteasomes. Immune system cells, especially antigen-presenting cells, express a higher basal level of immunoproteasomes. A well-described function of immunoproteasomes is to generate peptides with a hydrophobic C terminus that can be processed to fit in the groove of MHC class I molecules. This display of peptides on the cell surface allows surveillance by CD8 T cells of the adaptive immune system for pathogen-infected cells. Functions of immunoproteasomes, other than generating peptides for antigen presentation, are emerging from studies in immunoproteasome-deficient mice, and are complemented by recently described diseases linked to mutations or single-nucleotide polymorphisms in immunoproteasome subunits. Thus, this growing body of literature suggests a more pleiotropic role in cell function for the immunoproteasome.
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Affiliation(s)
- Deborah A Ferrington
- Department of Ophthalmology, University of Minnesota, Minneapolis, Minnesota, USA
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37
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Schmidt M, Finley D. Regulation of proteasome activity in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:13-25. [PMID: 23994620 DOI: 10.1016/j.bbamcr.2013.08.012] [Citation(s) in RCA: 318] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 08/05/2013] [Accepted: 08/07/2013] [Indexed: 12/13/2022]
Abstract
The ubiquitin-proteasome system (UPS) is the primary selective degradation system in the nuclei and cytoplasm of eukaryotic cells, required for the turnover of myriad soluble proteins. The hundreds of factors that comprise the UPS include an enzymatic cascade that tags proteins for degradation via the covalent attachment of a poly-ubiquitin chain, and a large multimeric enzyme that degrades ubiquitinated proteins, the proteasome. Protein degradation by the UPS regulates many pathways and is a crucial component of the cellular proteostasis network. Dysfunction of the ubiquitination machinery or the proteolytic activity of the proteasome is associated with numerous human diseases. In this review we discuss the contributions of the proteasome to human pathology, describe mechanisms that regulate the proteolytic capacity of the proteasome, and discuss strategies to modulate proteasome function as a therapeutic approach to ameliorate diseases associated with altered UPS function. This article is part of a Special Issue entitled: Ubiquitin-Proteasome System. Guest Editors: Thomas Sommer and Dieter H. Wolf.
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Affiliation(s)
- Marion Schmidt
- Albert Einstein College of Medicine, Department of Biochemistry, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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38
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Immunological control of herpes simplex virus infections. J Neurovirol 2013; 19:328-45. [PMID: 23943467 PMCID: PMC3758505 DOI: 10.1007/s13365-013-0189-3] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 07/08/2013] [Accepted: 07/17/2013] [Indexed: 12/24/2022]
Abstract
Herpes simplex virus type 1 (HSV-1) is capable of causing a latent infection in sensory neurons that lasts for the lifetime of the host. The primary infection is resolved following the induction of the innate immune response that controls replication of the virus until the adaptive immune response can clear the active infection. HSV-1-specific CD8+ T cells survey the ganglionic regions containing latently infected neurons and participate in preventing reactivation of HSV from latency. The long-term residence and migration dynamics of the T cells in the trigeminal ganglia appear to distinguish them from the traditional memory T cell subsets. Recently described tissue resident memory (TRM) T cells establish residence and survive for long periods in peripheral tissue compartments following antigen exposure. This review focuses on the immune system response to HSV-1 infection. Particular emphasis is placed on the evidence pointing to the HSV-1-specific CD8+ T cells in the trigeminal belonging to the TRM class of memory T cells and the role of TRM cells in virus infection, pathogenesis, latency, and disease.
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Kunjappu MJ, Hochstrasser M. Assembly of the 20S proteasome. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1843:2-12. [PMID: 23507199 DOI: 10.1016/j.bbamcr.2013.03.008] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 03/02/2013] [Accepted: 03/05/2013] [Indexed: 10/27/2022]
Abstract
The proteasome is a cellular protease responsible for the selective degradation of the majority of the intracellular proteome. It recognizes, unfolds, and cleaves proteins that are destined for removal, usually by prior attachment to polymers of ubiquitin. This macromolecular machine is composed of two subcomplexes, the 19S regulatory particle (RP) and the 20S core particle (CP), which together contain at least 33 different and precisely positioned subunits. How these subunits assemble into functional complexes is an area of active exploration. Here we describe the current status of studies on the assembly of the 20S proteasome (CP). The 28-subunit CP is found in all three domains of life and its cylindrical stack of four heptameric rings is well conserved. Though several CP subunits possess self-assembly properties, a consistent theme in recent years has been the need for dedicated assembly chaperones that promote on-pathway assembly. To date, a minimum of three accessory factors have been implicated in aiding the construction of the 20S proteasome. These chaperones interact with different assembling proteasomal precursors and usher subunits into specific slots in the growing structure. This review will focus largely on chaperone-dependent CP assembly and its regulation. This article is part of a Special Issue entitled: Ubiquitin-Proteasome System. Guest Editors: Thomas Sommer and Dieter H. Wolf.
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Affiliation(s)
- Mary J Kunjappu
- Department of Molecular, Cellular and Developmental Biology, Yale University, 266 Whitney Avenue P.O. Box 208114, New Haven, CT 06520-8114, USA
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Ebstein F, Kloetzel PM, Krüger E, Seifert U. Emerging roles of immunoproteasomes beyond MHC class I antigen processing. Cell Mol Life Sci 2012; 69:2543-58. [PMID: 22382925 PMCID: PMC11114860 DOI: 10.1007/s00018-012-0938-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Revised: 01/18/2012] [Accepted: 02/06/2012] [Indexed: 01/09/2023]
Abstract
The proteasome is a multi-catalytic protein complex whose primary function is the degradation of abnormal or foreign proteins. Upon exposure of cells to interferons (IFNs), the β1i/LMP2, β2i/MECL-1, and β5i/LMP7 subunits are induced and incorporated into newly synthesized immunoproteasomes (IP), which are thought to function solely as critical players in the optimization of the CD8(+) T-cell response. However, the observation that IP are present in several non-immune tissues under normal conditions and/or following pathological events militates against the view that its role is limited to MHC class I presentation. In support of this concept, the recent use of genetic models deficient for β1i/LMP2, β2i/MECL-1, or β5i/LMP7 has uncovered unanticipated functions for IP in innate immunity and non-immune processes. Herein, we review recent data in an attempt to clarify the role of IP beyond MHC class I epitope presentation with emphasis on its involvement in the regulation of protein homeostasis, cell proliferation, and cytokine gene expression.
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Affiliation(s)
- Frédéric Ebstein
- Institut für Biochemie, Charité-Universitätsmedizin Berlin Campus CVK, Oudenarderstr.16, 13347 Berlin, Germany
| | - Peter-Michael Kloetzel
- Institut für Biochemie, Charité-Universitätsmedizin Berlin Campus CVK, Oudenarderstr.16, 13347 Berlin, Germany
| | - Elke Krüger
- Institut für Biochemie, Charité-Universitätsmedizin Berlin Campus CVK, Oudenarderstr.16, 13347 Berlin, Germany
| | - Ulrike Seifert
- Institut für Biochemie, Charité-Universitätsmedizin Berlin Campus CVK, Oudenarderstr.16, 13347 Berlin, Germany
- Institut für Molekulare und Klinische Immunologie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany
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Huber EM, Groll M. Inhibitors for the immuno- and constitutive proteasome: current and future trends in drug development. Angew Chem Int Ed Engl 2012; 51:8708-20. [PMID: 22711561 DOI: 10.1002/anie.201201616] [Citation(s) in RCA: 148] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Indexed: 01/30/2023]
Abstract
Proteolytic degradation is an essential cellular process which is primarily carried out by the 20S proteasome core particle (CP), a protease of 720 kDa and 28 individual subunits. As a result of its central functional role, the proteasome represents an attractive drug target that has been extensively investigated during the last decade and validated by the approval of bortezomib by the US Food and Drug Administration (FDA). Currently, several optimized second-generation proteasome inhibitors are being explored as anticancer drugs in clinical trials, and most of them target both constitutive proteasomes (cCPs) and immunoproteasomes (iCPs). However, selective inhibition of the iCPs, a distinct class of proteasomes predominantly expressed in immune cells, appears to be a promising therapeutic rationale for the treatment of autoimmune disorders. Although a few selective agents have already been identified, the recently determined crystal structure of the iCP will further promote the development and optimization of iCP-selective compounds.
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Affiliation(s)
- Eva Maria Huber
- Center for Integrated Protein Science at the Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany.
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Huber EM, Groll M. Inhibitoren für das konstitutive Proteasom und das Immunoproteasom: aktuelle und zukünftige Tendenzen in der Medikamentenentwicklung. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201201616] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Huber EM, Basler M, Schwab R, Heinemeyer W, Kirk CJ, Groettrup M, Groll M. Immuno- and constitutive proteasome crystal structures reveal differences in substrate and inhibitor specificity. Cell 2012; 148:727-38. [PMID: 22341445 DOI: 10.1016/j.cell.2011.12.030] [Citation(s) in RCA: 370] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 11/17/2011] [Accepted: 12/02/2011] [Indexed: 01/19/2023]
Abstract
Constitutive proteasomes and immunoproteasomes shape the peptide repertoire presented by major histocompatibility complex class I (MHC-I) molecules by harboring different sets of catalytically active subunits. Here, we present the crystal structures of constitutive proteasomes and immunoproteasomes from mouse in the presence and absence of the epoxyketone inhibitor PR-957 (ONX 0914) at 2.9 Å resolution. Based on our X-ray data, we propose a unique catalytic feature for the immunoproteasome subunit β5i/LMP7. Comparison of ligand-free and ligand-bound proteasomes reveals conformational changes in the S1 pocket of β5c/X but not β5i, thereby explaining the selectivity of PR-957 for β5i. Time-resolved structures of yeast proteasome:PR-957 complexes indicate that ligand docking to the active site occurs only via the reactive head group and the P1 side chain. Together, our results support structure-guided design of inhibitory lead structures selective for immunoproteasomes that are linked to cytokine production and diseases like cancer and autoimmune disorders.
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Affiliation(s)
- Eva M Huber
- Center for Integrated Protein Science at the Department Chemie, Lehrstuhl für Biochemie, Technische Universität München, Garching D-85747, Germany
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Rockwell CE, Monaco JJ, Qureshi N. A critical role for the inducible proteasomal subunits LMP7 and MECL1 in cytokine production by activated murine splenocytes. Pharmacology 2012; 89:117-26. [PMID: 22398747 DOI: 10.1159/000336335] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 01/06/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND AND PURPOSE The proteasome is a multi-subunit complex that proteolytically cleaves proteins. The replacement of the constitutive proteasome subunits β1, β2, and/or β5 with the IFNγ-inducible subunits LMP2, MECL1, and/or LMP7 results in the 'immunoproteasome'. The inducible subunits change the cleavage specificities of the proteasome, but it is unclear whether they have functions in addition to this. The purpose of the present study was to determine the role of the proteasome in general, as well as LMP7 and MECL1 specifically, with regard to cytokine production by activated primary splenocytes. METHODS A LMP7/MECL1-null mouse was engineered to determine the roles of these subunits in cytokine production. Isolated splenocytes from wild-type and LMP7/MECL1-/- mice were treated with lactacystin and activated with PMA and ionomycin and subsequently cytokine mRNA levels were quantified. RESULTS The present study demonstrates that LMP7/MECL1 regulates the expression of IFNγ, IL4, IL10, IL2Rβ, GATA3, and t-bet. In contrast, the regulation of IL2, IL13, TNFα, and IL2Rα by the proteasome appears to occur independently of LMP7/MECL1. CONCLUSIONS Collectively, the present study demonstrates that LMP7 and MECL1 regulate cytokine expression, suggesting this system represents a novel mechanism for the regulation of cytokines and cytokine signaling.
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Affiliation(s)
- Cheryl E Rockwell
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Mich., USA
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Frankland-Searby S, Bhaumik SR. The 26S proteasome complex: an attractive target for cancer therapy. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1825:64-76. [PMID: 22037302 PMCID: PMC3242858 DOI: 10.1016/j.bbcan.2011.10.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Revised: 10/08/2011] [Accepted: 10/10/2011] [Indexed: 01/26/2023]
Abstract
The 26S proteasome complex engages in an ATP-dependent proteolytic degradation of a variety of oncoproteins, transcription factors, cell cycle specific cyclins, cyclin-dependent kinase inhibitors, ornithine decarboxylase, and other key regulatory cellular proteins. Thus, the proteasome regulates either directly or indirectly many important cellular processes. Altered regulation of these cellular events is linked to the development of cancer. Therefore, the proteasome has become an attractive target for the treatment of numerous cancers. Several proteasome inhibitors that target the proteolytic active sites of the 26S proteasome complex have been developed and tested for anti-tumor activities. These proteasome inhibitors have displayed impressive anti-tumor functions by inducing apoptosis in different tumor types. Further, the proteasome inhibitors have been shown to induce cell cycle arrest, and inhibit angiogenesis, cell-cell adhesion, cell migration, immune and inflammatory responses, and DNA repair response. A number of proteasome inhibitors are now in clinical trials to treat multiple myeloma and solid tumors. Many other proteasome inhibitors with different efficiencies are being developed and tested for anti-tumor activities. Several proteasome inhibitors currently in clinical trials have shown significantly improved anti-tumor activities when combined with other drugs such as histone deacetylase (HDAC) inhibitors, Akt (protein kinase B) inhibitors, DNA damaging agents, Hsp90 (heat shock protein 90) inhibitors, and lenalidomide. The proteasome inhibitor bortezomib is now in the clinic to treat multiple myeloma and mantle cell lymphoma. Here, we discuss the 26S proteasome complex in carcinogenesis and different proteasome inhibitors with their potential therapeutic applications in treatment of numerous cancers.
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Affiliation(s)
- Sarah Frankland-Searby
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
| | - Sukesh R. Bhaumik
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA
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Abstract
Immunoproteasomes (IPs) containing the interferon-inducible subunits β1i (LMP2), β2i (MECL-1), and β5i (LMP7) alter proteasomal cleavage preference, optimise the generation of peptide ligands of MHC class I molecules, alter cytokine profile, influence T-helper cell differentiation, and play a role in T-cell survival. Small molecule inhibitors are useful tools for probing the role of the immunoproteasome in immune functions. Here, we describe different methods to characterise immunoproteasome-selective inhibitors. Thereby, we provide the methodology to analyse the specificity and cell permeability of immunoproteasome inhibitors, as well as to functionally investigate immunoproteasome inhibitors in antigen presentation.
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Affiliation(s)
- Michael Basler
- Department of Biology, Division of Immunology, University of Konstanz, Konstanz, Germany.
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Basler M, Beck U, Kirk CJ, Groettrup M. The antiviral immune response in mice devoid of immunoproteasome activity. THE JOURNAL OF IMMUNOLOGY 2011; 187:5548-57. [PMID: 22013127 DOI: 10.4049/jimmunol.1101064] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The replacement of the catalytically active proteasome subunits β1, β2, and β5 by the immunoproteasome subunits low molecular mass polypeptide (LMP) 2 (β1i), multicatalytic endopeptidase complex-like-1 (MECL-1) (β2i), and LMP7 (β5i) is required for the production of numerous class I ligands. Hitherto, investigation of the immunoproteasome was confined to the analysis of mice deficient for one or two immunosubunits. In this study, we characterized LMP2(-/-)/MECL-1(-/-) double-deficient mice and used the well-defined LMP7-selective inhibitor ONX 0914 in these mice to generate mice lacking the activity of all immunoproteasome subunits. LMP2(-/-)/MECL-1(-/-) double-deficient mice had strongly reduced numbers of CD8(+) T cells in the spleen. Nevertheless, infection with the lymphocytic choriomeningits virus induced a normal cytotoxic T cell response in these mice, although the T cell response to several class I epitopes was altered. Treatment of LMP2(-/-)/MECL-1(-/-) double-deficient mice with the LMP7-selective inhibitor ONX 0914 elicited a strong CTL response in lymphocytic choriomeningitis virus-infected mice. Thereby, the T(CD8+) response to nucleoprotein 205-212, which is barely detectable in LMP2(-/-)/MECL-1(-/-) double-deficient mice, could be reverted to normal levels by LMP7 inhibition. Additional experiments could demonstrate that the increased CTL response to the nucleoprotein 205-212 in mice lacking functional immunoproteasome is due to an altered class I presentation of this epitope. Taken together, to our knowledge, this is the first study investigating viral infection in mice lacking activity of all three immunoproteasome subunits.
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Affiliation(s)
- Michael Basler
- Biotechnology Institute Thurgau at Constance University, CH-8280 Kreuzlingen, Switzerland.
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An antigenic peptide produced by reverse splicing and double asparagine deamidation. Proc Natl Acad Sci U S A 2011; 108:E323-31. [PMID: 21670269 DOI: 10.1073/pnas.1101892108] [Citation(s) in RCA: 109] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A variety of unconventional translational and posttranslational mechanisms contribute to the production of antigenic peptides, thereby increasing the diversity of the peptide repertoire presented by MHC class I molecules. Here, we describe a class I-restricted peptide that combines several posttranslational modifications. It is derived from tyrosinase and recognized by tumor-infiltrating lymphocytes isolated from a melanoma patient. This unusual antigenic peptide is made of two noncontiguous tyrosinase fragments that are spliced together in the reverse order. In addition, it contains two aspartate residues that replace the asparagines encoded in the tyrosinase sequence. We confirmed that this peptide is naturally presented at the surface of melanoma cells, and we showed that its processing sequentially requires translation of tyrosinase into the endoplasmic reticulum and its retrotranslocation into the cytosol, where deglycosylation of the two asparagines by peptide-N-glycanase turns them into aspartates by deamidation. This process is followed by cleavage and splicing of the appropriate fragments by the standard proteasome and additional transport of the resulting peptide into the endoplasmic reticulum through the transporter associated with antigen processing (TAP).
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Kremer M, Henn A, Kolb C, Basler M, Moebius J, Guillaume B, Leist M, Van den Eynde BJ, Groettrup M. Reduced immunoproteasome formation and accumulation of immunoproteasomal precursors in the brains of lymphocytic choriomeningitis virus-infected mice. THE JOURNAL OF IMMUNOLOGY 2010; 185:5549-60. [PMID: 20881186 DOI: 10.4049/jimmunol.1001517] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Tissue inflammation is accompanied by the cytokine-mediated replacement of constitutive proteasomes by immunoproteasomes that finally leads to an optimized generation of MHC class I restricted epitopes for Ag presentation. The brain is considered an immunoprivileged organ, where both the special anatomy as well as active tolerance mechanisms repress the development of inflammatory responses and help to prevent immunopathological damage. We analyzed the immunoproteasome expression in the brain after an infection with lymphocytic choriomeningitis virus (LCMV) and could show that LCMV-infection of mice leads to the transcriptional induction of inducible proteasome subunits in the brain. However, compared with other organs, i.p. and even intracranial infection with LCMV only led to a faint expression of mature immunoproteasome in the brain and resulted in the accumulation of immunoproteasomal precursors. By immunohistology, we could identify microglia-like cells as the main producers of immunoproteasome, whereas in astrocytes immunoproteasome expression was almost exclusively restricted to nuclei. Neither the immunoproteasome subunits low molecular mass polypeptide 2 nor multicatalytic endopeptidase complex-like-1 were detected in neurons or oligodendrocytes. In vitro studies of IFN-γ-stimulated primary astrocytes suggested that the observed accumulation of immunoproteasomal precursor complexes takes place in this cell population. Functionally, the lack of immunoproteasomes protracted and lowered the severity of LCMV-induced meningitis in LMP7(-/-) mice suggesting a contribution of immunoproteasomes in microglia to exacerbate immunopathological damage. We postulate a posttranslationally regulated mechanism that prevents abundant and inappropriate immunoproteasome assembly in the brain and may contribute to the protection of poorly regenerating cells of the CNS from immunopathological destruction.
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Affiliation(s)
- Marcel Kremer
- Division of Immunology, Department of Biology, Constance University, Konstanz, Germany
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Bardag-Gorce F, Oliva J, Li J, French BA, French SW. SAMe prevents the induction of the immunoproteasome and preserves the 26S proteasome in the DDC-induced MDB mouse model. Exp Mol Pathol 2010; 88:353-62. [PMID: 20223233 PMCID: PMC3315394 DOI: 10.1016/j.yexmp.2010.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Accepted: 03/02/2010] [Indexed: 10/19/2022]
Abstract
Mallory-Denk bodies (MDBs) form in the liver of alcoholic patients. This occurs because of the accumulation and aggregation of ubiquitinated cytokeratins, which hypothetically is due to the ubiquitin-proteasome pathway's (UPP) failure to degrade the cytokeratins. The experimental model of MDB formation was used in which MDBs were induced by refeeding DDC to drug-primed mice. The gene expression and protein levels of LMP2, LMP7 and MECL-1, the catalytic subunits in the immunoproteasome, as well as FAT10, were increased in the liver cells forming MDBs but not in the intervening normal hepatocytes. Chymotrypsin-like activity of the UPP was decreased by DDC refeeding, indicating that a switch from the UPP to the immunoproteasome had occurred at the expense of the 26S proteasome. The failure of the UPP to digest cytokeratins would explain MDB aggregate formation. SAMe prevented the decrease in UPP activity, the increase in LMP2, LMP7, and MECL-1 protein levels and MDB formation induced by DDC. DDC refeeding also induced the TNFalpha and IFNgamma receptors. SAMe prevented the increase in the TNFalpha and IFNgamma receptors, supporting the idea that TNFalpha and IFNgamma were responsible for the up regulation of LMP2, LPM7, and FAT10. These results support the conclusion that MDBs form in FAT10 over-expressing hepatocytes where the up regulation of the immunoproteasome occurs at the expense of the 26S proteasome.
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Affiliation(s)
- Fawzia Bardag-Gorce
- Department of Pathology, LABioMed at Harbor-UCLA Medical Center, Torrance, CA 90509, USA.
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