Similar Datasets
Project description:AMYLOIDOGENIC LIGHT CHAINS IMPAIR PLASMA CELL SURVIVAL
| PRJNA734939 | ENA
Project description:We investigated the N- and C-terminome of the LCs proteoforms in fibrils extracted from the hearts of a patient affected by AL amyloidosis, using a proteomic approach based on N- and C-terminal residues derivatization, followed by mapping of fragmentation sites on the structures of fibrillar LCs
2024-07-02 | PXD049301 | Pride
Project description:Amyloid diseases are characterized by the misfolding of a precursor protein that leads to amyloid fibril formation. Despite the fact that there are different precursors, some commonalities in the misfolding mechanism are thought to exist. In light chain amyloidosis (AL), the immunoglobulin light chain forms amyloid fibrils that deposit in the extracellular space of vital organs. AL proteins are thermodynamically destabilized compared to non-amyloidogenic proteins and some studies have linked this instability to increased fibril formation rates. Here we present the crystal structures of two highly homologous AL proteins, AL-12 and AL-103. This structural study shows that these proteins retain the canonical germ line dimer interface. We highlight important structural alterations in two loops flanking the dimer interface and correlate these results with the somatic mutations present in AL-12 and AL-103. We suggest that these alterations are informative structural features that are likely contributing to protein instability that leads to conformational changes involved in the initial events of amyloid formation.
| S-EPMC2840394 | biostudies-literature
Project description:IntroductionMultiple myeloma (MM) and light chain monoclonal gammopathy of undetermined significance (LCMGUS) are plasma cell disorders associated with the secretion of monoclonal free light-chain (LC) proteins. Due to the high concentrations of LC in circulation, both of these populations are at risk for developing LC-associated amyloidosis (AL) - a protein misfolding disease characterized by the deposition of LC protein fibrils in organs and tissues, leading to dysfunction and significant morbidity. At present, accurate identification of subjects at risk for developing amyloidosis is not possible, but with the advent of novel, amyloid-targeted therapies, identification of pre-symptomatic individuals is of clinical import.MethodsTo address this, a competition assay has been developed to discern LC proteins with enhanced amyloidogenic potential. Numerous factors that may influence the efficacy of the assay have been evaluated to yield optimal conditions.ResultsUsing a panel of nine patient-derived LC, we have demonstrated that amyloid-associated LC inhibited the recruitment of a biotinyl-λ6 variable domain by homologous amyloid-like fibrils significantly more than MM LC (p < .01).ConclusionThe assay accurately discriminated AL from MM patient populations, suggesting that it may aid in the identification of patients with monoclonal gammopathies who have an increased risk of developing amyloidosis.
| S-EPMC6333307 | biostudies-literature
Project description:Immunoglobulin light chain (LC) amyloidosis is a life-threatening disease whose understanding and treatment is complicated by vast numbers of patient-specific mutations. To address molecular origins of the disease, we explored 14 patient-derived and engineered proteins related to κ1-family germline genes IGKVLD-33*01 and IGKVLD-39*01. Hydrogen-deuterium exchange mass spectrometry analysis of local conformational dynamics in full-length recombinant LCs and their fragments was integrated with studies of thermal stability, proteolytic susceptibility, amyloid formation, and amyloidogenic sequence propensities using spectroscopic, electron microscopic and bioinformatics tools. The results were mapped on the atomic structures of native and fibrillary proteins. Proteins from two κ1 subfamilies showed unexpected differences. Compared to their germline counterparts, amyloid LC related to IGKVLD-33*01 was less stable and formed amyloid faster, whereas amyloid LC related to IGKVLD-39*01 had similar stability and formed amyloid slower. These and other differences suggest different major factors influencing amyloid formation. In 33*01-related amyloid LC, these factors involved mutation-induced destabilization of the native structure and probable stabilization of amyloid. The atypical behavior of 39*01-related amyloid LC tracked back to increased dynamics/exposure of amyloidogenic segments in βC’V and βEV that could initiate aggregation, combined with decreased dynamics/exposure near the C23-Cys88 disulfide whose rearrangement is rate-limiting to amyloidogenesis. The results suggest distinct amyloidogenic pathways for closely related LCs and point to the antigen-binding regions CDR1 and CDR3, which are linked via the conserved internal disulfide, as key factors in amyloid formation by various LCs.
2023-05-23 | PXD039682 | Pride
Project description:Light-chain amyloidosis (AL) is a devastating protein-misfolding disease characterized by abnormal proliferation of plasma cells in the bone marrow that secrete monoclonal immunoglobulin light chains that misfold and form amyloid fibrils, thus causing organ failure and death. Numerous reports on different protein-misfolding diseases show that soluble oligomeric species populated by amyloidogenic proteins can be quite toxic to cells. However, it is not well established whether the soluble immunoglobulin light-chain species found in circulation in patients with AL are toxic to cells in target organs. We determined the cellular toxicity of two well-characterized light-chain variable domain proteins from cardiac AL patients and their corresponding germline protein, devoid of somatic mutations. Our results show that the soluble form of the AL proteins we characterized are toxic to cardiomyocytes, and that the species found in cell culture correspond, for the most part, to the species present in circulation in these patients.
| S-EPMC3032327 | biostudies-literature
Project description:In Ig light-chain (LC) amyloidosis (AL), the unique antibody LC protein that is secreted by monoclonal plasma cells in each patient misfolds and/or aggregates, a process leading to organ degeneration. As a step toward developing treatments for AL patients with substantial cardiac involvement who have difficulty tolerating existing chemotherapy regimens, we introduce small-molecule kinetic stabilizers of the native dimeric structure of full-length LCs, which can slow or stop the amyloidogenicity cascade at its origin. A protease-coupled fluorescence polarization-based high-throughput screen was employed to identify small molecules that kinetically stabilize LCs. NMR and X-ray crystallographic data demonstrate that at least one structural family of hits bind at the LC-LC dimerization interface within full-length LCs, utilizing variable-domain residues that are highly conserved in most AL patients. Stopping the amyloidogenesis cascade at the beginning is a proven strategy to ameliorate postmitotic tissue degeneration.
| S-EPMC6486714 | biostudies-literature
Project description:Immunoglobulin light chain (LC) amyloidosis (AL) is a life-threatening human disease wherein free monoclonal LCs deposit in vital organs. To determine what makes some LCs amyloidogenic, we explored patient-based amyloidogenic and non-amyloidogenic recombinant LCs from the λ6 subtype prevalent in AL. Hydrogen-deuterium exchange mass spectrometry, structural stability, proteolysis, and amyloid growth studies revealed that the antigen-binding CDR1 loop is the least protected part in the variable domain of λ6 LC, particularly in the AL variant. N32T substitution in CRD1 is identified as a driver of amyloid formation. Substitution N32T increased the amyloidogenic propensity of CDR1 loop, decreased its protection in the native structure, and accelerated amyloid growth in the context of other AL substitutions. The destabilizing effects of N32T propagated across the molecule increasing its dynamics in regions ~30Å away from the substitution site. Such striking long-range effects of a conservative point substitution in a dynamic surface loop may be relevant to Ig function. Comparison of patient-derived and engineered proteins showed that N32T interactions with other substitution sites must contribute to amyloidosis. The results suggest that CDR1 is critical in amyloid formation by other λ6 LCs.
2021-11-25 | PXD026528 | Pride
Project description:Light chain amyloidosis (AL) is caused by the aberrant overproduction of immunoglobulin light chains (LCs). The resulting abnormally high LC concentrations in blood lead to deposit formation in the heart and other target organs. Organ damage is caused not only by the accumulation of bulky amyloid deposits, but extensive clinical data indicate that circulating soluble LCs also exert cardiotoxic effects. The nematode C. elegans has been validated to recapitulate LC soluble toxicity in vivo, and in such a model a role for copper ions in increasing LC soluble toxicity has been reported. Here, we applied microscale thermophoresis, isothermal calorimetry and thermal melting to demonstrate the specific binding of Cu2+ to the variable domain of amyloidogenic H7 with a sub-micromolar affinity. Histidine residues present in the LC sequence are not involved in the binding, and yet their mutation to Ala reduces the soluble toxicity of H7. Copper ions bind to and destabilize the variable domains and induce a limited stabilization in this domain. In summary, the data reported here, elucidate the biochemical bases of the Cu2+-induced toxicity; moreover, they also show that copper binding is just one of the several biochemical traits contributing to LC soluble in vivo toxicity.
| S-EPMC8780072 | biostudies-literature
Project description:Antibody light chain amyloidosis is a rare disease caused by fibril formation of secreted immunoglobulin light chains (LCs). The huge variety of antibody sequences puts a serious challenge to drug discovery. The green tea polyphenol epigallocatechin-3-gallate (EGCG) is known to interfere with fibril formation in general. Here we present solution- and solid-state NMR studies as well as MD simulations to characterise the interaction of EGCG with LC variable domains. We identified two distinct EGCG binding sites, both of which include a proline as an important recognition element. The binding sites were confirmed by site-directed mutagenesis and solid-state NMR analysis. The EGCG-induced protein complexes are unstructured. We propose a general mechanistic model for EGCG binding to a conserved site in LCs. We find that EGCG reacts selectively with amyloidogenic mutants. This makes this compound a promising lead structure, that can handle the immense sequence variability of antibody LCs.
| S-EPMC5269747 | biostudies-literature