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Del Pozo-Yauner L, Herrera GA, Perez Carreon JI, Turbat-Herrera EA, Rodriguez-Alvarez FJ, Ruiz Zamora RA. Role of the mechanisms for antibody repertoire diversification in monoclonal light chain deposition disorders: when a friend becomes foe. Front Immunol 2023; 14:1203425. [PMID: 37520549 PMCID: PMC10374031 DOI: 10.3389/fimmu.2023.1203425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/20/2023] [Indexed: 08/01/2023] Open
Abstract
The adaptive immune system of jawed vertebrates generates a highly diverse repertoire of antibodies to meet the antigenic challenges of a constantly evolving biological ecosystem. Most of the diversity is generated by two mechanisms: V(D)J gene recombination and somatic hypermutation (SHM). SHM introduces changes in the variable domain of antibodies, mostly in the regions that form the paratope, yielding antibodies with higher antigen binding affinity. However, antigen recognition is only possible if the antibody folds into a stable functional conformation. Therefore, a key force determining the survival of B cell clones undergoing somatic hypermutation is the ability of the mutated heavy and light chains to efficiently fold and assemble into a functional antibody. The antibody is the structural context where the selection of the somatic mutations occurs, and where both the heavy and light chains benefit from protective mechanisms that counteract the potentially deleterious impact of the changes. However, in patients with monoclonal gammopathies, the proliferating plasma cell clone may overproduce the light chain, which is then secreted into the bloodstream. This places the light chain out of the protective context provided by the quaternary structure of the antibody, increasing the risk of misfolding and aggregation due to destabilizing somatic mutations. Light chain-derived (AL) amyloidosis, light chain deposition disease (LCDD), Fanconi syndrome, and myeloma (cast) nephropathy are a diverse group of diseases derived from the pathologic aggregation of light chains, in which somatic mutations are recognized to play a role. In this review, we address the mechanisms by which somatic mutations promote the misfolding and pathological aggregation of the light chains, with an emphasis on AL amyloidosis. We also analyze the contribution of the variable domain (VL) gene segments and somatic mutations on light chain cytotoxicity, organ tropism, and structure of the AL fibrils. Finally, we analyze the most recent advances in the development of computational algorithms to predict the role of somatic mutations in the cardiotoxicity of amyloidogenic light chains and discuss the challenges and perspectives that this approach faces.
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Affiliation(s)
- Luis Del Pozo-Yauner
- Department of Pathology, University of South Alabama-College of Medicine, Mobile, AL, United States
| | - Guillermo A. Herrera
- Department of Pathology, University of South Alabama-College of Medicine, Mobile, AL, United States
| | | | - Elba A. Turbat-Herrera
- Department of Pathology, University of South Alabama-College of Medicine, Mobile, AL, United States
- Mitchell Cancer Institute, University of South Alabama-College of Medicine, Mobile, AL, United States
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Dobenecker MW, Marcello J, Becker A, Rudensky E, Bhanu NV, Carrol T, Garcia BA, Prinjha R, Yurchenko V, Tarakhovsky A. The catalytic domain of the histone methyltransferase NSD2/MMSET is required for the generation of B1 cells in mice. FEBS Lett 2020; 594:3324-3337. [PMID: 32862441 DOI: 10.1002/1873-3468.13903] [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: 06/12/2020] [Revised: 07/19/2020] [Accepted: 07/29/2020] [Indexed: 12/23/2022]
Abstract
Humoral immunity in mammals relies on the function of two developmentally and functionally distinct B-cell subsets-B1 and B2 cells. While B2 cells are responsible for the adaptive response to environmental antigens, B1 cells regulate the production of polyreactive and low-affinity antibodies for innate humoral immunity. The molecular mechanism of B-cell specification into different subsets is understudied. In this study, we identified lysine methyltransferase NSD2 (MMSET/WHSC1) as a critical regulator of B1 cell development. In contrast to its minor impact on B2 cells, deletion of the catalytic domain of NSD2 in primary B cells impairs the generation of B1 lineage. Thus, NSD2, a histone H3 K36 dimethylase, is the first-in-class epigenetic regulator of a B-cell lineage in mice.
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Affiliation(s)
- Marc-Werner Dobenecker
- Laboratory of Immune Cell Epigenetics and Signaling, Rockefeller University, New York, NY, USA.,Bristol-Meyers Squibb, Princeton, NJ, USA
| | - Jonas Marcello
- Laboratory of Immune Cell Epigenetics and Signaling, Rockefeller University, New York, NY, USA
| | - Annette Becker
- Laboratory of Immune Cell Epigenetics and Signaling, Rockefeller University, New York, NY, USA.,Departments of Pediatrics, Cell and Developmental Biology, Weill Cornell Medical College, New York, NY, USA
| | - Eugene Rudensky
- Laboratory of Immune Cell Epigenetics and Signaling, Rockefeller University, New York, NY, USA.,NYU Langone Medical Center and School of Medicine, New York, NY, USA
| | - Natarajan V Bhanu
- Penn Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Thomas Carrol
- Bioinformatics Resource Center, Rockefeller University, New York, NY, USA
| | - Benjamin A Garcia
- Penn Epigenetics Institute, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rabinder Prinjha
- Epinova DPU, Immuno-Inflammation Therapy Area, GlaxoSmithKline R&D, Stevenage, UK
| | - Vyacheslav Yurchenko
- Laboratory of Immune Cell Epigenetics and Signaling, Rockefeller University, New York, NY, USA.,Sechenov First Moscow State Medical University, Moscow, Russia.,Life Science Research Centre, University of Ostrava, Ostrava, Czech Republic
| | - Alexander Tarakhovsky
- Laboratory of Immune Cell Epigenetics and Signaling, Rockefeller University, New York, NY, USA
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Morris DL, Rothstein TL. Abnormal transcription factor induction through the surface immunoglobulin M receptor of B-1 lymphocytes. J Exp Med 1993; 177:857-61. [PMID: 8436914 PMCID: PMC2190944 DOI: 10.1084/jem.177.3.857] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Populations of murine peritoneal B-1 and splenic B-2 cells, highly purified by negative selection techniques, were used to demonstrate that B-1 cells completely fail to enter cell cycle in response to surface immunoglobulin M (sIgM) crosslinking without any decrease in cell number or viability. This failure of B-1 cell responsiveness appears to represent a specific defect in sIgM-derived signaling inasmuch as stimulation to enter S phase occurs normally in response to activated and fixed T cells, and to lipopolysaccharide (LPS). The level at which sIgM signaling fails was determined by evaluating the nuclear expression of the transcription factor complex, NF-kappa B, whose sIgM-mediated induction in B-2 cells is dependent on protein kinase C (PKC) activation but is independent of protein synthesis. There was no induction of nuclear NF-kappa B in B-1 cells stimulated by sIgM crosslinking, although NF-kappa B was stimulated by phorbol myristate acetate and by LPS. In contrast, NF-kappa B was induced in B-2 cells by all three stimuli. Thus, in B-1 cells, the sIgM-mediated induction of a transcription factor that is substantially stimulated by anti-IgM in B-2 cells is blocked. However, all sIgM-derived signaling in B-1 cells was not impaired inasmuch as anti-IgM increased I-A antigen expression. These results strongly suggest that sIgM receptor-mediated signaling in B-1 cells is interrupted early in the signal transduction pathway, at a point proximal to the activation of PKC. These results further demonstrate that transcription factor induction can be used to analyze the level at which receptor-mediated signaling is blocked.
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Affiliation(s)
- D L Morris
- Department of Medicine, Boston University Medical Center, Massachusetts 02118
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