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Järvinen E, Suomi F, Stewart JB, Guala D, Valori M, Jansson L, Nieminen J, McWilliams TG, Tienari PJ. Cultured lymphocytes' mitochondrial genome integrity is not altered by cladribine. Clin Exp Immunol 2023; 214:304-313. [PMID: 37860849 PMCID: PMC10719213 DOI: 10.1093/cei/uxad112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 08/29/2023] [Accepted: 10/10/2023] [Indexed: 10/21/2023] Open
Abstract
Cladribine tablets are a treatment for multiple sclerosis with effects on lymphocytes, yet its mode of action has not been fully established. Here, we analyzed the effects of cladribine on mitochondrial DNA integrity in lymphocytes. We treated cultured human T-cell lines (CCRF-CEM and Jurkat) with varying concentrations of cladribine to mimic the slow cell depletion observed in treated patients. The CCRF-CEM was more susceptible to cladribine than Jurkat cells. In both cells, mitochondrial protein synthesis, mitochondrial DNA copy number, and mitochondrial cytochrome-c oxidase-I mRNA mutagenesis was not affected by cladribine, while caspase-3 cleavage was detected in Jurkat cells at 100 nM concentration. Cladribine treatment at concentrations up to 10 nM in CCRF-CEM and 100 nM in Jurkat cells did not induce significant increase in mitochondrial DNA mutations. Peripheral blood mononuclear cells from eight multiple sclerosis patients and four controls were cultured with or without an effective dose of cladribine (5 nM). However, we did not find any differences in mitochondrial DNA somatic mutations in lymphocyte subpopulations (CD4+, CD8+, and CD19+) between treated versus nontreated cells. The overall mutation rate was similar in patients and controls. When different lymphocyte subpopulations were compared, greater mitochondrial DNA mutation levels were detected in CD8+ (P = 0.014) and CD4+ (P = 0.038) as compared to CD19+ cells, these differences were independent of cladribine treatment. We conclude that T cells have more detectable mitochondrial DNA mutations than B cells, and cladribine has no detectable mutagenic effect on lymphocyte mitochondrial genome nor does it impair mitochondrial function in human T-cell lines.
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Affiliation(s)
- Elina Järvinen
- Merck OY, Espoo, Finland (an affiliate of Merck KGaA, Darmstadt, Germany)
| | - Fumi Suomi
- Translational Stem Cell Biology and Metabolism Program, Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - James B Stewart
- Max Planck Institute for Biology of Ageing, Cologne, Germany
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Faculty of Medical Sciences Newcastle University, Newcastle Upon Tyne, UK
| | - Dimitri Guala
- Merck AB, Solna, Sweden (an affiliate of Merck KGaA, Darmstadt, Germany)
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Miko Valori
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Lilja Jansson
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- Helsinki University Hospital, Neurocenter, Helsinki, Finland
| | - Janne Nieminen
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- Helsinki University Hospital, Neurocenter, Helsinki, Finland
| | - Thomas G McWilliams
- Translational Stem Cell Biology and Metabolism Program, Research Program Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Pentti J Tienari
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- Helsinki University Hospital, Neurocenter, Helsinki, Finland
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2
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Van Horebeek L, David M, Dedoncker N, Mallants K, Bijnens B, Goris A, Dubois B. A targeted sequencing extension for transcript genotyping in single-cell transcriptomics. Life Sci Alliance 2023; 6:e202301971. [PMID: 37696578 PMCID: PMC10494938 DOI: 10.26508/lsa.202301971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 08/17/2023] [Accepted: 08/29/2023] [Indexed: 09/13/2023] Open
Abstract
As no existing methods within the single-cell RNA sequencing repertoire combine genotyping of specific genomic loci with high throughput, we evaluated a straightforward, targeted sequencing approach as an extension to high-throughput droplet-based single-cell RNA sequencing. Overlaying standard gene expression data with transcript level genotype information provides a strategy to study the impact of genetic variants. Here, we describe this targeted sequencing extension, explain how to process the data and evaluate how technical parameters such as amount of input cDNA, number of amplification rounds, and sequencing depth influence the number of transcripts detected. Finally, we demonstrate how targeted sequencing can be used in two contexts: (1) simultaneous investigation of the presence of a somatic variant and its potential impact on the transcriptome of affected cells and (2) evaluation of allele-specific expression of a germline variant in ad hoc cell subsets. Through these and other comparable applications, our targeted sequencing extension has the potential to improve our understanding of functional effects caused by genetic variation.
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Affiliation(s)
- Lies Van Horebeek
- https://ror.org/05f950310 Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Margaux David
- https://ror.org/05f950310 Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Nina Dedoncker
- https://ror.org/05f950310 Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Klara Mallants
- https://ror.org/05f950310 Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Baukje Bijnens
- https://ror.org/05f950310 Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - An Goris
- https://ror.org/05f950310 Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Bénédicte Dubois
- https://ror.org/05f950310 Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, Leuven, Belgium
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium
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3
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Lehikoinen J, Valori M, Jääskeläinen AJ, Laakso SM, Arstila TP, Tienari PJ. High Epstein-Barr virus capsid antigen IgG level associates with the carriership of CD8+ T cell somatic mutations in the STAT3 SH2 domain. Clin Immunol 2023; 255:109733. [PMID: 37572949 DOI: 10.1016/j.clim.2023.109733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 08/03/2023] [Accepted: 08/09/2023] [Indexed: 08/14/2023]
Abstract
High carrier prevalence of STAT3 SH2 domain somatic mutations was recently discovered in CD8+ T cells. We found these low-allele-fraction clones in 26% of donors, without difference between multiple sclerosis (MS) patients and controls. Here we tested whether anti-viral antibodies associate with the carriership of these mutant clones. We compared antibody responses against common viruses in mutation carriers vs. non-carriers. Plasma samples of 152 donors (92 MS patients, 60 controls) were analyzed for antibodies against cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus-6A and parvovirus B19. The mutation carrier status associated with EBV VCA IgG level (p = 0.005) and remained significant after logistic regression (p = 0.036). This association was contributed similarly by MS patients and controls. These results suggest that EBV contributes to the generation or growth of these clones. The pathogenic role of the STAT3 mutant clones in MS is presently unclear, but their detailed characterization warrants further study.
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Affiliation(s)
- Joonas Lehikoinen
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; Department of Neurology, Brain Center, Helsinki University Hospital, Helsinki, Finland.
| | - Miko Valori
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Anne J Jääskeläinen
- HUS Diagnostic Center, Clinical Microbiology, University of Helsinki and Helsinki University Hospital
| | - Sini M Laakso
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; Department of Neurology, Brain Center, Helsinki University Hospital, Helsinki, Finland
| | - T Petteri Arstila
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; Department of Bacteriology and Immunology, Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Pentti J Tienari
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland; Department of Neurology, Brain Center, Helsinki University Hospital, Helsinki, Finland
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4
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Xie Z, Zeidan AM. CHIPing away the progression potential of CHIP: A new reality in the making. Blood Rev 2023; 58:101001. [PMID: 35989137 DOI: 10.1016/j.blre.2022.101001] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/15/2022]
Abstract
Over the past few years, we have gained a deeper understanding of clonal hematopoiesis of indeterminate potential (CHIP), especially with regard to the epidemiology, clinical sequelae, and mechanical aspects. However, interventional strategies to prevent or delay the potential negative consequences of CHIP remain underdeveloped. In this review, we highlight the latest updates on clonal hematopoiesis research, including molecular mechanisms and clinical implications, with a particular focus on the evolving strategies for the interventions that are being evaluated in ongoing observational and interventional trials. There remains an urgent need to formulate standardized and evidence-based recommendations and guidelines for evaluating and managing individuals with clonal hematopoiesis. In addition, patient-centric endpoints must be defined for clinical trials, which will enable us to continue the robust development of effective preventive strategies and improve clinical outcomes.
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Affiliation(s)
- Zhuoer Xie
- Division of Hematology, Department of Internal Medicine, Mayo Clinic, Rochester, MN, United States
| | - Amer M Zeidan
- Section of Hematology, Department of Internal Medicine, Yale Cancer Center and Smilow Cancer Hospital, Yale University School of Medicine, CT, United States.
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Evans MA, Walsh K. Clonal hematopoiesis, somatic mosaicism, and age-associated disease. Physiol Rev 2023; 103:649-716. [PMID: 36049115 PMCID: PMC9639777 DOI: 10.1152/physrev.00004.2022] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 07/19/2022] [Accepted: 08/02/2022] [Indexed: 12/15/2022] Open
Abstract
Somatic mosaicism, the occurrence of multiple genetically distinct cell clones within the same tissue, is an evitable consequence of human aging. The hematopoietic system is no exception to this, where studies have revealed the presence of expanded blood cell clones carrying mutations in preleukemic driver genes and/or genetic alterations in chromosomes. This phenomenon is referred to as clonal hematopoiesis and is remarkably prevalent in elderly individuals. While clonal hematopoiesis represents an early step toward a hematological malignancy, most individuals will never develop blood cancer. Somewhat unexpectedly, epidemiological studies have found that clonal hematopoiesis is associated with an increase in the risk of all-cause mortality and age-related disease, particularly in the cardiovascular system. Studies using murine models of clonal hematopoiesis have begun to shed light on this relationship, suggesting that driver mutations in mature blood cells can causally contribute to aging and disease by augmenting inflammatory processes. Here we provide an up-to-date review of clonal hematopoiesis within the context of somatic mosaicism and aging and describe recent epidemiological studies that have reported associations with age-related disease. We will also discuss the experimental studies that have provided important mechanistic insight into how driver mutations promote age-related disease and how this knowledge could be leveraged to treat individuals with clonal hematopoiesis.
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Affiliation(s)
- Megan A Evans
- Hematovascular Biology Center, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Kenneth Walsh
- Hematovascular Biology Center, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
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Van Horebeek L, Dedoncker N, Dubois B, Goris A. Frequent somatic mosaicism in T lymphocyte subsets in individuals with and without multiple sclerosis. Front Immunol 2022; 13:993178. [PMID: 36618380 PMCID: PMC9817019 DOI: 10.3389/fimmu.2022.993178] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 12/09/2022] [Indexed: 12/25/2022] Open
Abstract
Background Somatic variants are variations in an individual's genome acquired after the zygotic stadium and result from mitotic errors or not (fully) repaired DNA damage. Objectives To investigate whether somatic mosaicism in T lymphocyte subsets is enriched early in multiple sclerosis (MS). Methods We identified somatic variants with variant allele fractions ≥1% across the whole exome in CD4+ and CD8+ T lymphocytes of 21 treatment-naive MS patients with <5 years of disease duration and 16 partially age-matched healthy controls. We investigated the known somatic STAT3 variant p.Y640F in peripheral blood in a larger cohort of 446 MS patients and 259 controls. Results All subjects carried 1-142 variants in CD4+ or CD8+ T lymphocytes. Variants were more common, more abundant, and increased with age in CD8+ T lymphocytes. Somatic variants were common in the genes DNMT3A and especially STAT3. Overall, the presence or abundance of somatic variants, including the STAT3 p.Y640F variant, did not differ between MS patients and controls. Conclusions Somatic variation in T lymphocyte subsets is widespread in both control individuals and MS patients. Somatic mosaicism in T lymphocyte subsets is not enriched in early MS and thus unlikely to contribute to MS risk, but future research needs to address whether a subset of variants influences disease susceptibility.
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Affiliation(s)
- Lies Van Horebeek
- Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Nina Dedoncker
- Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, Katholieke Universiteit (KU) Leuven, Leuven, Belgium
| | - Bénédicte Dubois
- Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, Katholieke Universiteit (KU) Leuven, Leuven, Belgium,Department of Neurology, University Hospitals Leuven, Leuven, Belgium
| | - An Goris
- Laboratory for Neuroimmunology, Department of Neurosciences, Leuven Brain Institute, Katholieke Universiteit (KU) Leuven, Leuven, Belgium,*Correspondence: An Goris,
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Bedri SK, Evertsson B, Khademi M, Al Nimer F, Olsson T, Hillert J, Glaser A. Copy number variations across the blood-brain barrier in multiple sclerosis. Ann Clin Transl Neurol 2022; 9:962-976. [PMID: 35560551 PMCID: PMC9268884 DOI: 10.1002/acn3.51573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 03/30/2022] [Accepted: 04/12/2022] [Indexed: 12/29/2022] Open
Abstract
Objective Multiple sclerosis (MS) is a neuroinflammatory disease where immune cells cross the blood–brain barrier (BBB) into the central nervous system (CNS). What predisposes these immune cells to cross the BBB is still unknown. Here, we examine the possibility that genomic rearrangements could predisposespecific immune cells in the peripheral blood to cross the BBB and form sub‐populations of cells involved in the inflammatory process in the CNS. Methods We compared copy number variations in paired peripheral blood mononuclear cells (PBMCs) and cerebrospinal fluid (CSF) cells from MS patients. Thereafter, using next generation sequencing, we studied the T‐cell receptor beta (TRB) locus rearrangements and profiled the αβ T cell repertoire in peripheral CD4+ and CD8+ T cells and in the CSF. Results We identified deletions in the T‐cell receptor alpha/delta (TRA/D), gamma (TRG), and TRB loci in CSF cells compared to PBMCs. Further characterization revealed diversity of the TRB locus which was used to describe the character and clonal expansion of T cells in the CNS. T‐cell repertoire profiling from either side of the BBB concluded that the most frequent clones in the CSF samples are unique to an individual. Furthermore, we observed a difference in the proportion of expanded T‐cell clones when comparing samples from MS patients in relapse and remission with opposite trends in CSF and peripheral blood. Interpretation This study provides a characterization of the T cells in the CSF and might indicate a role of expanded clones in MS pathogenicity.
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Affiliation(s)
- Sahl Khalid Bedri
- Department of Clinical Neuroscience and Centrum for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Björn Evertsson
- Department of Clinical Neuroscience and Centrum for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Karolinska University Hospital, Tema Neuro, Stockholm, Sweden
| | - Mohsen Khademi
- Department of Clinical Neuroscience and Centrum for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Faiez Al Nimer
- Department of Clinical Neuroscience and Centrum for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Karolinska University Hospital, Tema Neuro, Stockholm, Sweden
| | - Tomas Olsson
- Department of Clinical Neuroscience and Centrum for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Karolinska University Hospital, Tema Neuro, Stockholm, Sweden
| | - Jan Hillert
- Department of Clinical Neuroscience and Centrum for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Karolinska University Hospital, Tema Neuro, Stockholm, Sweden
| | - Anna Glaser
- Department of Clinical Neuroscience and Centrum for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
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8
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Alburquerque-González B, López-Abellán MD, Luengo-Gil G, Montoro-García S, Conesa-Zamora P. Design of Personalized Neoantigen RNA Vaccines Against Cancer Based on Next-Generation Sequencing Data. Methods Mol Biol 2022; 2547:165-185. [PMID: 36068464 DOI: 10.1007/978-1-0716-2573-6_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The good clinical results of immune checkpoint inhibitors (ICIs) in recent cancer therapy and the success of RNA vaccines against SARS-nCoV2 have provided important lessons to the scientific community. On the one hand, the efficacy of ICI depends on the number and immunogenicity of tumor neoantigens (TNAs) which unfortunately are not abundantly expressed in many cancer subtypes. On the other hand, novel RNA vaccines have significantly improved both the stability and immunogenicity of mRNA and its efficient delivery, this way overcoming past technique limitations and also allowing a quick vaccine development at the same time. These two facts together have triggered a resurgence of therapeutic cancer vaccines which can be designed to include individual TNAs and be synthesized in a timeframe short enough to be suitable for the tailored treatment of a given cancer patient.In this chapter, we explain the pipeline for the synthesis of TNA-carrying RNA vaccines which encompasses several steps such as individual tumor next-generation sequencing (NGS), selection of immunogenic TNAs, nucleic acid synthesis, drug delivery systems, and immunogenicity assessment, all of each step comprising different alternatives and variations which will be discussed.
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Affiliation(s)
- Begoña Alburquerque-González
- Pathology and Histology Department Facultad de Ciencias de la Salud, UCAM Universidad Católica San Antonio de Murcia, Murcia, Spain
| | - María Dolores López-Abellán
- Laboratory Medicine Department, Group of Molecular Pathology and Pharmacogenetics, Biomedical Research Institute from Murcia (IMIB), Hospital Universitario Santa Lucía, Cartagena, Spain
| | - Ginés Luengo-Gil
- Laboratory Medicine Department, Group of Molecular Pathology and Pharmacogenetics, Biomedical Research Institute from Murcia (IMIB), Hospital Universitario Santa Lucía, Cartagena, Spain
| | - Silvia Montoro-García
- Cell Culture Lab, Facultad de Ciencias de la Salud, UCAM Universidad Católica San Antonio de Murcia, Murcia, Spain
| | - Pablo Conesa-Zamora
- Pathology and Histology Department Facultad de Ciencias de la Salud, UCAM Universidad Católica San Antonio de Murcia, Murcia, Spain.
- Laboratory Medicine Department, Group of Molecular Pathology and Pharmacogenetics, Biomedical Research Institute from Murcia (IMIB), Hospital Universitario Santa Lucía, Cartagena, Spain.
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9
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Valori M, Jansson L, Tienari PJ. CD8+ cell somatic mutations in multiple sclerosis patients and controls-Enrichment of mutations in STAT3 and other genes implicated in hematological malignancies. PLoS One 2021; 16:e0261002. [PMID: 34874980 PMCID: PMC8651110 DOI: 10.1371/journal.pone.0261002] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 11/23/2021] [Indexed: 01/14/2023] Open
Abstract
Somatic mutations have a central role in cancer but their role in other diseases such as common autoimmune disorders is not clear. Previously we and others have demonstrated that especially CD8+ T cells in blood can harbor persistent somatic mutations in some patients with multiple sclerosis (MS) and rheumatoid arthritis. Here we concentrated on CD8+ cells in more detail and tested (i) how commonly somatic mutations are detectable, (ii) does the overall mutation load differ between MS patients and controls, and (iii) do the somatic mutations accumulate non-randomly in certain genes? We separated peripheral blood CD8+ cells from newly diagnosed relapsing MS patients (n = 21) as well as matched controls (n = 21) and performed next-generation sequencing of the CD8+ cells' DNA, limiting our search to a custom panel of 2524 immunity and cancer related genes, which enabled us to obtain a median sequencing depth of over 2000x. We discovered nonsynonymous somatic mutations in all MS patients' and controls' CD8+ cell DNA samples, with no significant difference in number between the groups (p = 0.60), at a median allelic fraction of 0.5% (range 0.2-8.6%). The mutations showed statistically significant clustering especially to the STAT3 gene, and also enrichment to the SMARCA2, DNMT3A, SOCS1 and PPP3CA genes. Known activating STAT3 mutations were found both in MS patients and controls and overall 1/5 of the mutations were previously described cancer mutations. The detected clustering suggests a selection advantage of the mutated CD8+ clones and calls for further research on possible phenotypic effects.
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Affiliation(s)
- Miko Valori
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- * E-mail:
| | - Lilja Jansson
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- Department of Neurology, Neurocenter, Helsinki University Hospital, Helsinki, Finland
| | - Pentti J. Tienari
- Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
- Department of Neurology, Neurocenter, Helsinki University Hospital, Helsinki, Finland
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10
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Affiliation(s)
- Satu Mustjoki
- From the Translational Immunology Research Program and the Department of Clinical Chemistry and Hematology, University of Helsinki, the Hematology Research Unit, Helsinki University Hospital Comprehensive Cancer Center, and the iCAN Digital Precision Cancer Medicine Flagship - all in Helsinki (S.M.); and the Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, MD (N.S.Y.)
| | - Neal S Young
- From the Translational Immunology Research Program and the Department of Clinical Chemistry and Hematology, University of Helsinki, the Hematology Research Unit, Helsinki University Hospital Comprehensive Cancer Center, and the iCAN Digital Precision Cancer Medicine Flagship - all in Helsinki (S.M.); and the Hematology Branch, National Heart, Lung, and Blood Institute, Bethesda, MD (N.S.Y.)
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11
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Somatic mutations in lymphocytes in patients with immune-mediated aplastic anemia. Leukemia 2021; 35:1365-1379. [PMID: 33785863 PMCID: PMC8102188 DOI: 10.1038/s41375-021-01231-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 02/04/2021] [Accepted: 03/12/2021] [Indexed: 12/31/2022]
Abstract
The prevalence and functional impact of somatic mutations in nonleukemic T cells is not well characterized, although clonal T-cell expansions are common. In immune-mediated aplastic anemia (AA), cytotoxic T-cell expansions are shown to participate in disease pathogenesis. We investigated the mutation profiles of T cells in AA by a custom panel of 2533 genes. We sequenced CD4+ and CD8+ T cells of 24 AA patients and compared the results to 20 healthy controls and whole-exome sequencing of 37 patients with AA. Somatic variants were common both in patients and healthy controls but enriched to AA patients’ CD8+ T cells, which accumulated most mutations on JAK-STAT and MAPK pathways. Mutation burden was associated with CD8+ T-cell clonality, assessed by T-cell receptor beta sequencing. To understand the effect of mutations, we performed single-cell sequencing of AA patients carrying STAT3 or other mutations in CD8+ T cells. STAT3 mutated clone was cytotoxic, clearly distinguishable from other CD8+ T cells, and attenuated by successful immunosuppressive treatment. Our results suggest that somatic mutations in T cells are common, associate with clonality, and can alter T-cell phenotype, warranting further investigation of their role in the pathogenesis of AA.
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12
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Multiple Sclerosis-Associated hnRNPA1 Mutations Alter hnRNPA1 Dynamics and Influence Stress Granule Formation. Int J Mol Sci 2021; 22:ijms22062909. [PMID: 33809384 PMCID: PMC7998649 DOI: 10.3390/ijms22062909] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 12/21/2022] Open
Abstract
Evidence indicates that dysfunctional heterogeneous ribonucleoprotein A1 (hnRNPA1; A1) contributes to the pathogenesis of neurodegeneration in multiple sclerosis. Understanding molecular mechanisms of neurodegeneration in multiple sclerosis may result in novel therapies that attenuate neurodegeneration, thereby improving the lives of MS patients with multiple sclerosis. Using an in vitro, blue light induced, optogenetic protein expression system containing the optogene Cryptochrome 2 and a fluorescent mCherry reporter, we examined the effects of multiple sclerosis-associated somatic A1 mutations (P275S and F281L) in A1 localization, cluster kinetics and stress granule formation in real-time. We show that A1 mutations caused cytoplasmic mislocalization, and significantly altered the kinetics of A1 cluster formation/dissociation, and the quantity and size of clusters. A1 mutations also caused stress granule formation to occur more quickly and frequently in response to blue light stimulation. This study establishes a live cell optogenetics imaging system to probe localization and association characteristics of A1. It also demonstrates that somatic mutations in A1 alter its function and promote stress granule formation, which supports the hypothesis that A1 dysfunction may exacerbate neurodegeneration in multiple sclerosis.
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13
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Kelkka T, Savola P, Bhattacharya D, Huuhtanen J, Lönnberg T, Kankainen M, Paalanen K, Tyster M, Lepistö M, Ellonen P, Smolander J, Eldfors S, Yadav B, Khan S, Koivuniemi R, Sjöwall C, Elo LL, Lähdesmäki H, Maeda Y, Nishikawa H, Leirisalo-Repo M, Sokka-Isler T, Mustjoki S. Adult-Onset Anti-Citrullinated Peptide Antibody-Negative Destructive Rheumatoid Arthritis Is Characterized by a Disease-Specific CD8+ T Lymphocyte Signature. Front Immunol 2020; 11:578848. [PMID: 33329548 PMCID: PMC7732449 DOI: 10.3389/fimmu.2020.578848] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 10/15/2020] [Indexed: 11/30/2022] Open
Abstract
Rheumatoid arthritis (RA) is a complex autoimmune disease targeting synovial joints. Traditionally, RA is divided into seropositive (SP) and seronegative (SN) disease forms, the latter consisting of an array of unrelated diseases with joint involvement. Recently, we described a severe form of SN-RA that associates with characteristic joint destruction. Here, we sought biological characteristics to differentiate this rare but aggressive anti-citrullinated peptide antibody-negative destructive RA (CND-RA) from early seropositive (SP-RA) and seronegative rheumatoid arthritis (SN-RA). We also aimed to study cytotoxic CD8+ lymphocytes in autoimmune arthritis. CND-RA, SP-RA and SN-RA were compared to healthy controls to reveal differences in T-cell receptor beta (TCRβ) repertoire, cytokine levels and autoantibody repertoires. Whole-exome sequencing (WES) followed by single-cell RNA-sequencing (sc-RNA-seq) was performed to study somatic mutations in a clonally expanded CD8+ lymphocyte population in an index patient. A unique TCRβ signature was detected in CND-RA patients. In addition, CND-RA patients expressed higher levels of the bone destruction-associated TNFSF14 cytokine. Blood IgG repertoire from CND-RA patients recognized fewer endogenous proteins than SP-RA patients’ repertoires. Using WES, we detected a stable mutation profile in the clonally expanded CD8+ T-cell population characterized by cytotoxic gene expression signature discovered by sc-RNA-sequencing. Our results identify CND-RA as an independent RA subset and reveal a CND-RA specific TCR signature in the CD8+ lymphocytes. Improved classification of seronegative RA patients underlines the heterogeneity of RA and also, facilitates development of improved therapeutic options for the treatment resistant patients.
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Affiliation(s)
- Tiina Kelkka
- Hematology Research Unit Helsinki, University of Helsinki, Helsinki, Finland.,Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland.,Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland.,Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Paula Savola
- Hematology Research Unit Helsinki, University of Helsinki, Helsinki, Finland.,Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland.,Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland.,Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Dipabarna Bhattacharya
- Hematology Research Unit Helsinki, University of Helsinki, Helsinki, Finland.,Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland.,Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland.,Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Jani Huuhtanen
- Hematology Research Unit Helsinki, University of Helsinki, Helsinki, Finland.,Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland.,Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland.,Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Tapio Lönnberg
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland
| | - Matti Kankainen
- Hematology Research Unit Helsinki, University of Helsinki, Helsinki, Finland.,Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland.,Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Kirsi Paalanen
- Rheumatology, Jyväskylä Central Hospital, Jyväskylä, Finland
| | - Mikko Tyster
- Hematology Research Unit Helsinki, University of Helsinki, Helsinki, Finland.,Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland.,Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland.,Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Maija Lepistö
- Institute for Molecular Medicine Finland (FIMM), Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Pekka Ellonen
- Institute for Molecular Medicine Finland (FIMM), Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Johannes Smolander
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland
| | - Samuli Eldfors
- Institute for Molecular Medicine Finland (FIMM), Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Finland
| | - Bhagwan Yadav
- Hematology Research Unit Helsinki, University of Helsinki, Helsinki, Finland.,Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland.,Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland.,Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
| | - Sofia Khan
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland
| | - Riitta Koivuniemi
- Rheumatology, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
| | - Christopher Sjöwall
- Department of Biomedical and Clinical Sciences, Division of Inflammation and Infection, Linköping University, Linköping, Sweden
| | - Laura L Elo
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.,Institute of Biomedicine, University of Turku, Turku, Finland
| | - Harri Lähdesmäki
- Department of Computer Science, Aalto University School of Science, Espoo, Finland
| | - Yuka Maeda
- Division of Cancer Immunology, Research Institute/Exploratory Oncology Research and Clinical Trial Center (EPOC), National Cancer Center, Tokyo, Japan
| | - Hiroyoshi Nishikawa
- Division of Cancer Immunology, Research Institute/Exploratory Oncology Research and Clinical Trial Center (EPOC), National Cancer Center, Tokyo, Japan
| | | | - Tuulikki Sokka-Isler
- Rheumatology, Jyväskylä Central Hospital, Jyväskylä, Finland.,University of Eastern Finland, Faculty of Health Sciences, Kuopio, Finland
| | - Satu Mustjoki
- Hematology Research Unit Helsinki, University of Helsinki, Helsinki, Finland.,Department of Hematology, Helsinki University Hospital Comprehensive Cancer Center, Helsinki, Finland.,Department of Clinical Chemistry and Hematology, University of Helsinki, Helsinki, Finland.,Translational Immunology Research Program, University of Helsinki, Helsinki, Finland
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14
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Van Horebeek L, Dubois B, Goris A. Somatic Variants: New Kids on the Block in Human Immunogenetics. Trends Genet 2019; 35:935-947. [PMID: 31668909 DOI: 10.1016/j.tig.2019.09.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/23/2019] [Accepted: 09/27/2019] [Indexed: 01/21/2023]
Abstract
Somatic variants are not inherited but acquired during an individual's lifetime, and individuals are increasingly considered as complex mosaics of genetically distinct cells. Whereas this concept is long-recognized in cancer, this review focuses on the growing role of somatic variants in immune cells in nonmalignant immune-related disorders, such as primary immunodeficiency and autoimmune diseases. Older case reports described somatic variants early in development, leading to large numbers of affected cells and severe phenotypes. Thanks to technological evolution, it is now feasible to detect somatic variants occurring later in life and affecting fewer cells. Hence, only recently is the scale at which somatic variants contribute to monogenic diseases being uncovered and is their contribution to complex diseases being explored systematically.
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Affiliation(s)
- L Van Horebeek
- KU Leuven Department of Neurosciences, Laboratory for Neuroimmunology, 3000 Leuven, Belgium; Leuven Brain Institute, 3000 Leuven, Belgium
| | - B Dubois
- KU Leuven Department of Neurosciences, Laboratory for Neuroimmunology, 3000 Leuven, Belgium; Leuven Brain Institute, 3000 Leuven, Belgium; University Hospitals Leuven, Department of Neurology, 3000 Leuven, Belgium
| | - A Goris
- KU Leuven Department of Neurosciences, Laboratory for Neuroimmunology, 3000 Leuven, Belgium; Leuven Brain Institute, 3000 Leuven, Belgium.
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