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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: 7] [Impact Index Per Article: 3.5] [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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Xu L, Su Y. Genetic pathogenesis of immunoglobulin light chain amyloidosis: basic characteristics and clinical applications. Exp Hematol Oncol 2021; 10:43. [PMID: 34284823 PMCID: PMC8290569 DOI: 10.1186/s40164-021-00236-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/11/2021] [Indexed: 02/05/2023] Open
Abstract
Immunoglobulin light chain amyloidosis (AL) is an indolent plasma cell disorder characterized by free immunoglobulin light chain (FLC) misfolding and amyloid fibril deposition. The cytogenetic pattern of AL shows profound similarity with that of other plasma cell disorders but harbors distinct features. AL can be classified into two primary subtypes: non-hyperdiploidy and hyperdiploidy. Non-hyperdiploidy usually involves immunoglobulin heavy chain translocations, and t(11;14) is the hallmark of this disease. T(11;14) is associated with low plasma cell count but high FLC level and displays distinct response outcomes to different treatment modalities. Hyperdiploidy is associated with plasmacytosis and subclone formation, and it generally confers a neutral or inferior prognostic outcome. Other chromosome abnormalities and driver gene mutations are considered as secondary cytogenetic aberrations that occur during disease evolution. These genetic aberrations contribute to the proliferation of plasma cells, which secrete excess FLC for amyloid deposition. Other genetic factors, such as specific usage of immunoglobulin light chain germline genes and light chain somatic mutations, also play an essential role in amyloid fibril deposition in AL. This paper will propose a framework of AL classification based on genetic aberrations and discuss the amyloid formation of AL from a genetic aspect.
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Affiliation(s)
- Linchun Xu
- Shantou University Medical College, Shantou, 515031, Guangdong, China
- The First Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Yongzhong Su
- Department of Hematology, The First Affiliated Hospital of Shantou University Medical College, Shantou, 515041, Guangdong, China.
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Methods to study the structure of misfolded protein states in systemic amyloidosis. Biochem Soc Trans 2021; 49:977-985. [PMID: 33929491 DOI: 10.1042/bst20201022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/08/2021] [Accepted: 04/12/2021] [Indexed: 12/19/2022]
Abstract
Systemic amyloidosis is defined as a protein misfolding disease in which the amyloid is not necessarily deposited within the same organ that produces the fibril precursor protein. There are different types of systemic amyloidosis, depending on the protein constructing the fibrils. This review will focus on recent advances made in the understanding of the structural basis of three major forms of systemic amyloidosis: systemic AA, AL and ATTR amyloidosis. The three diseases arise from the misfolding of serum amyloid A protein, immunoglobulin light chains or transthyretin. The presented advances in understanding were enabled by recent progress in the methodology available to study amyloid structures and protein misfolding, in particular concerning cryo-electron microscopy (cryo-EM) and nuclear magnetic resonance (NMR) spectroscopy. An important observation made with these techniques is that the structures of previously described in vitro formed amyloid fibrils did not correlate with the structures of amyloid fibrils extracted from diseased tissue, and that in vitro fibrils were typically more protease sensitive. It is thus possible that ex vivo fibrils were selected in vivo by their proteolytic stability.
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López Sánchez HA, Kathuria SV, Fernández Velasco DA. The Folding Pathway of 6aJL2. J Phys Chem B 2021; 125:1997-2008. [PMID: 33620231 DOI: 10.1021/acs.jpcb.0c08534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
One-third of the reported cases of light chain amyloidosis are related to the germ line λ6 family; remarkably, healthy individuals express this type of protein in just 2% of the peripheral blood and bone marrow B-cells. The appearance of the disease has been related to the inherent properties of this protein family. A recombinant representative model for λ6 proteins called 6aJL2 containing the amino acid sequence encoded by the 6a and JL2 germ line genes was previously designed and synthesized to study the properties of this family. Previous work on 6aJL2 suggested a simple two-state folding model at 25 °C; no intermediate could be identified either by kinetics or by fluorescence and circular dichroism equilibrium studies, although the presence of an intermediate that is populated at ∼2.4 M urea was suggested by size exclusion chromatography. In this study we employed classic equilibrium and kinetic experiments and analysis to elucidate the detailed folding mechanism of this protein. We identify species that are kinetically accessible and/or are populated at equilibrium. We describe the presence of intermediate and native-like species and propose a five-species folding mechanism at 25 °C at short incubation times, similar to and consistent with those observed in other proteins of this fold. The formation of intermediates in the mechanism of 6aJL2 is faster than that proposed for a Vκ light chain, which could be an important distinction in the amyloidogenic potential of both germ lines.
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Affiliation(s)
- Haven A López Sánchez
- Laboratorio de FísicoQuímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
| | - Sagar V Kathuria
- Biochemistry and Molecular Pharmacology Department, University of Massachusetts Medical School, Worcester, Massachusetts 01655, United States
| | - D Alejandro Fernández Velasco
- Laboratorio de FísicoQuímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, México
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Molecular mechanism of amyloidogenic mutations in hypervariable regions of antibody light chains. J Biol Chem 2021; 296:100334. [PMID: 33508322 PMCID: PMC7949129 DOI: 10.1016/j.jbc.2021.100334] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/14/2021] [Accepted: 01/22/2021] [Indexed: 12/14/2022] Open
Abstract
Systemic light chain (AL) amyloidosis is a fatal protein misfolding disease in which excessive secretion, misfolding, and subsequent aggregation of free antibody light chains eventually lead to deposition of amyloid plaques in various organs. Patient-specific mutations in the antibody VL domain are closely linked to the disease, but the molecular mechanisms by which certain mutations induce misfolding and amyloid aggregation of antibody domains are still poorly understood. Here, we compare a patient VL domain with its nonamyloidogenic germline counterpart and show that, out of the five mutations present, two of them strongly destabilize the protein and induce amyloid fibril formation. Surprisingly, the decisive, disease-causing mutations are located in the highly variable complementarity determining regions (CDRs) but exhibit a strong impact on the dynamics of conserved core regions of the patient VL domain. This effect seems to be based on a deviation from the canonical CDR structures of CDR2 and CDR3 induced by the substitutions. The amyloid-driving mutations are not necessarily involved in propagating fibril formation by providing specific side chain interactions within the fibril structure. Rather, they destabilize the VL domain in a specific way, increasing the dynamics of framework regions, which can then change their conformation to form the fibril core. These findings reveal unexpected influences of CDR-framework interactions on antibody architecture, stability, and amyloid propensity.
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Rudiño-Piñera E, Peláez-Aguilar ÁE, Amero C, Díaz-Vilchis A. Crystal structure of 6aJL2-R24G light chain variable domain: Does crystal packing explain amyloid fibril formation? Biochem Biophys Rep 2019; 20:100682. [PMID: 31517067 PMCID: PMC6728755 DOI: 10.1016/j.bbrep.2019.100682] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 08/02/2019] [Accepted: 08/15/2019] [Indexed: 11/19/2022] Open
Abstract
Light chain amyloidosis is one of the most common systemic amyloidosis, characterized by the deposition of immunoglobulin light variable domain as insoluble amyloid fibrils in vital organs, leading to the death of patients. Germline λ6a is closely related with this disease and has been reported that 25% of proteins encoded by this germline have a change at position 24 where an Arg is replaced by a Gly (R24G). This germline variant reduces protein stability and increases the propensity to form amyloid fibrils. In this work, the crystal structure of 6aJL2-R24G has been determined to 2.0 Å resolution by molecular replacement. Crystal belongs to space group I212121 (PDB ID 5JPJ) and there are two molecules in the asymmetric unit. This 6aJL2-R24G structure as several related in PDB (PDB entries: 5C9K, 2W0K, 5IR3 and 1PW3) presents by crystal packing the formation of an octameric assembly in a helicoidal arrangement, which has been proposed as an important early stage in amyloid fibril aggregation. However, other structures of other protein variants in PDB (PDB entries: 3B5G, 3BDX, 2W0L, 1CD0 and 2CD0) do not make the octameric assembly, regardless their capacity to form fibers in vitro or in vivo. The analysis presented here shows that the ability to form the octameric assembly in a helicoidal arrangement in crystallized light chain immunoglobulin proteins is not required for amyloid fibril formation in vitro. In addition, the fundamental role of partially folded states in the amyloid fibril formation in vitro, is not described in any crystallographic structure published or analyzed here, being those structures, in any case examples of proteins in their native states. Those partially folded states have been recently described by cryo-EM studies, showing the necessity of structural changes in the variants before the amyloid fiber formation process starts.
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Affiliation(s)
- Enrique Rudiño-Piñera
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa, Cuernavaca, Morelos, 62210, Mexico
| | - Ángel E. Peláez-Aguilar
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Colonia Chamilpa, Cuernavaca, Morelos, 62209, Mexico
| | - Carlos Amero
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Colonia Chamilpa, Cuernavaca, Morelos, 62209, Mexico
| | - Adelaida Díaz-Vilchis
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa, Cuernavaca, Morelos, 62210, Mexico
- Corresponding author.
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Maya-Martinez R, French-Pacheco L, Valdés-García G, Pastor N, Amero C. Different Dynamics in 6aJL2 Proteins Associated with AL Amyloidosis, a Conformational Disease. Int J Mol Sci 2019; 20:E4078. [PMID: 31438515 PMCID: PMC6747610 DOI: 10.3390/ijms20174078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/16/2019] [Accepted: 05/22/2019] [Indexed: 12/12/2022] Open
Abstract
Light-chain amyloidosis (AL) is the most common systemic amyloidosis and is caused by the deposition of mainly insoluble immunoglobulin light chain amyloid fibrils in multiple organs, causing organ failure and eventually death. The germ-line λ6a has been implicated in AL, where a single point mutant at amino acid 24 (6aJL2-R24G) has been observed in around 25% of patient samples. Structural analysis has shown only subtle differences between both proteins; nevertheless, 6aJL2-R24G is more prone to form amyloid fibrils. To improve our understanding of the role of protein flexibility in amyloid fibril formation, we have used a combination of solution nuclear magnetic resonance spectroscopy and molecular dynamics simulations to complement the structural insight with dynamic knowledge. Fast timescale dynamics (ps-ns) were equivalent for both proteins, but suggested exchange events for some residues. Even though most of the intermediate dynamics (μs-ms) occurred at a similar region for both proteins, the specific characteristics are very different. A minor population detected in the dispersion experiments could be associated with the formation of an off-pathway intermediate that protects from fiber formation more efficiently in the germ-line protein. Moreover, we found that the hydrogen bond patterns for both proteins are similar, but the lifetime for the mutant is significantly reduced; as a consequence, there is a decrease in the stability of the tertiary structure that extends throughout the protein and leads to an increase in the propensity to form amyloid fibers.
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Affiliation(s)
- Roberto Maya-Martinez
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Leidys French-Pacheco
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Gilberto Valdés-García
- Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Nina Pastor
- Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico
| | - Carlos Amero
- Laboratorio de Bioquímica y Resonancia Magnética Nuclear, Centro de Investigaciones Químicas, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca 62209, Mexico.
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Lecoq L, Wiegand T, Rodriguez‐Alvarez FJ, Cadalbert R, Herrera GA, del Pozo‐Yauner L, Meier BH, Böckmann A. A Substantial Structural Conversion of the Native Monomer Leads to in‐Register Parallel Amyloid Fibril Formation in Light‐Chain Amyloidosis. Chembiochem 2019; 20:1027-1031. [DOI: 10.1002/cbic.201800732] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Lauriane Lecoq
- Molecular Microbiology and Structural BiochemistryLabex EcofectUMR 5086 CNRS/Université de Lyon 7, passage du Vercors 69367 Lyon France
| | - Thomas Wiegand
- Physical ChemistryETH Zürich Vladimir-Prelog Weg 2 8093 Zürich Switzerland
| | | | - Riccardo Cadalbert
- Molecular Microbiology and Structural BiochemistryLabex EcofectUMR 5086 CNRS/Université de Lyon 7, passage du Vercors 69367 Lyon France
| | - Guillermo A. Herrera
- Department of Pathology and Translational PathobiologyLSU Health Sciences Center Shreveport 1501 Kings Highway Shreveport LA 71103 USA
| | - Luis del Pozo‐Yauner
- Instituto Nacional de Medicina Genómica Periférico Sur No. 4809 14610 Mexico City México
- Department of Pathology and Translational PathobiologyLSU Health Sciences Center Shreveport 1501 Kings Highway Shreveport LA 71103 USA
| | - Beat H. Meier
- Physical ChemistryETH Zürich Vladimir-Prelog Weg 2 8093 Zürich Switzerland
| | - Anja Böckmann
- Molecular Microbiology and Structural BiochemistryLabex EcofectUMR 5086 CNRS/Université de Lyon 7, passage du Vercors 69367 Lyon France
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