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Lauring MC, Basu U. Somatic hypermutation mechanisms during lymphomagenesis and transformation. Curr Opin Genet Dev 2024; 85:102165. [PMID: 38428317 DOI: 10.1016/j.gde.2024.102165] [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: 11/08/2023] [Revised: 01/31/2024] [Accepted: 02/02/2024] [Indexed: 03/03/2024]
Abstract
B cells undergoing physiologically programmed or aberrant genomic alterations provide an opportune system to study the causes and consequences of genome mutagenesis. Activated B cells in germinal centers express activation-induced cytidine deaminase (AID) to accomplish physiological somatic hypermutation (SHM) of their antibody-encoding genes. In attempting to diversify their immunoglobulin (Ig) heavy- and light-chain genes, several B-cell clones successfully optimize their antigen-binding affinities. However, SHM can sometimes occur at non-Ig loci, causing genetic alternations that lay the foundation for lymphomagenesis, particularly diffuse large B-cell lymphoma. Thus, SHM acts as a double-edged sword, bestowing superb humoral immunity at the potential risk of initiating disease. We refer to off-target, non-Ig AID mutations - that are often but not always associated with disease - as aberrant SHM (aSHM). A key challenge in understanding SHM and aSHM is determining how AID targets and mutates specific DNA sequences in the Ig loci to generate antibody diversity and non-Ig genes to initiate lymphomagenesis. Herein, we discuss some current advances regarding the regulation of AID's DNA mutagenesis activity in B cells.
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Affiliation(s)
- Max C Lauring
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York 10032, USA.
| | - Uttiya Basu
- Department of Microbiology and Immunology, Vagelos College of Physicians and Surgeons, Columbia University, New York 10032, USA.
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Rogers GL, Huang C, Mathur A, Huang X, Chen HY, Stanten K, Morales H, Chang CH, Kezirian EJ, Cannon PM. Reprogramming human B cells with custom heavy chain antibodies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.28.546944. [PMID: 37425794 PMCID: PMC10327003 DOI: 10.1101/2023.06.28.546944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
We describe a genome editing strategy to reprogram the immunoglobulin heavy chain (IgH) locus of human B cells to express custom molecules that respond to immunization. These heavy chain antibodies (HCAbs) comprise a custom antigen-recognition domain linked to an Fc domain derived from the IgH locus and can be differentially spliced to express either B cell receptor (BCR) or secreted antibody isoforms. The HCAb editing platform is highly flexible, supporting antigen-binding domains based on both antibody and non-antibody components, and also allowing alterations in the Fc domain. Using HIV Env protein as a model antigen, we show that B cells edited to express anti-Env HCAbs support the regulated expression of both BCRs and antibodies, and respond to Env antigen in a tonsil organoid model of immunization. In this way, human B cells can be reprogrammed to produce customized therapeutic molecules with the potential for in vivo amplification.
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Affiliation(s)
- Geoffrey L. Rogers
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Chun Huang
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Atishay Mathur
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Xiaoli Huang
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Hsu-Yu Chen
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Kalya Stanten
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Heidy Morales
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Chan-Hua Chang
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Eric J. Kezirian
- Department of Otolaryngology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
| | - Paula M. Cannon
- Department of Molecular Microbiology and Immunology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
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Martin OA, Thomas M, Marquet M, Bruzeau C, Garot A, Brousse M, Bender S, Carrion C, Choi JE, Vuong BQ, Gearhart PJ, Maul RW, Le Noir S, Pinaud E. The IgH Eµ-MAR regions promote UNG-dependent error-prone repair to optimize somatic hypermutation. Front Immunol 2023; 14:1030813. [PMID: 36865553 PMCID: PMC9971809 DOI: 10.3389/fimmu.2023.1030813] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 01/13/2023] [Indexed: 02/16/2023] Open
Abstract
Intoduction Two scaffold/matrix attachment regions (5'- and 3'-MARsEµ ) flank the intronic core enhancer (cEµ) within the immunoglobulin heavy chain locus (IgH). Besides their conservation in mice and humans, the physiological role of MARsEµ is still unclear and their involvement in somatic hypermutation (SHM) has never been deeply evaluated. Methods Our study analyzed SHM and its transcriptional control in a mouse model devoid of MARsEµ , further combined to relevant models deficient for base excision repair and mismatch repair. Results We observed an inverted substitution pattern in of MARsEµ -deficient animals: SHM being decreased upstream from cEµ and increased downstream of it. Strikingly, the SHM defect induced by MARsEµ -deletion was accompanied by an increase of sense transcription of the IgH V region, excluding a direct transcription-coupled effect. Interestingly, by breeding to DNA repair-deficient backgrounds, we showed that the SHM defect, observed upstream from cEµ in this model, was not due to a decrease in AID deamination but rather the consequence of a defect in base excision repair-associated unfaithful repair process. Discussion Our study pointed out an unexpected "fence" function of MARsEµ regions in limiting the error-prone repair machinery to the variable region of Ig gene loci.
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Affiliation(s)
- Ophélie A Martin
- Laboratoire Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), Université de Limoges, CNRS Unité Mixte de Recherche 7276, Inserm Unité 1262, Limoges, France
| | - Morgane Thomas
- Laboratoire Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), Université de Limoges, CNRS Unité Mixte de Recherche 7276, Inserm Unité 1262, Limoges, France
| | - Marie Marquet
- Laboratoire Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), Université de Limoges, CNRS Unité Mixte de Recherche 7276, Inserm Unité 1262, Limoges, France
| | - Charlotte Bruzeau
- Laboratoire Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), Université de Limoges, CNRS Unité Mixte de Recherche 7276, Inserm Unité 1262, Limoges, France
| | - Armand Garot
- Laboratoire Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), Université de Limoges, CNRS Unité Mixte de Recherche 7276, Inserm Unité 1262, Limoges, France
| | - Mylène Brousse
- Laboratoire Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), Université de Limoges, CNRS Unité Mixte de Recherche 7276, Inserm Unité 1262, Limoges, France
| | - Sébastien Bender
- Laboratoire Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), Université de Limoges, CNRS Unité Mixte de Recherche 7276, Inserm Unité 1262, Limoges, France.,Centre Hospitalier Universitaire Dupuytren, Service d'Immunopathologie, Limoges, France
| | - Claire Carrion
- Laboratoire Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), Université de Limoges, CNRS Unité Mixte de Recherche 7276, Inserm Unité 1262, Limoges, France
| | - Jee Eun Choi
- The Graduate Center, The City University of New York, New York, NY, United States
| | - Bao Q Vuong
- The Graduate Center, The City University of New York, New York, NY, United States
| | - Patricia J Gearhart
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Robert W Maul
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Sandrine Le Noir
- Laboratoire Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), Université de Limoges, CNRS Unité Mixte de Recherche 7276, Inserm Unité 1262, Limoges, France
| | - Eric Pinaud
- Laboratoire Contrôle de la Réponse Immune B et des Lymphoproliférations (CRIBL), Université de Limoges, CNRS Unité Mixte de Recherche 7276, Inserm Unité 1262, Limoges, France
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