Dataset Information

A conservative point mutation in a dynamic antigen-binding loop of human immunoglobulin λ6 light chain promotes pathologic amyloid formation

ABSTRACT: 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.

INSTRUMENT(S): Synapt MS

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: John R. Engen

LAB HEAD: John R. Engen

PROVIDER: PXD026528 | Pride | 2021-11-25

REPOSITORIES: Pride

ACCESS DATA

Similar Datasets

Project description:Collagen deposition is a key process during idiopathic pulmonary fibrosis (IPF); however, little is known about the dynamics of collagen formation during disease development. Tissue samples of early stages of human disease are not readily available and it is difficult to identify changes in collagen content, since standard collagen analysis does not distinguish between 'old' and 'new' collagen. Therefore, the current study aimed to (i) investigate the dynamics of new collagen formation in mice using bleomycin-induced lung fibrosis in which newly synthesized collagen was labelled with deuterated water and (ii) use this information to identify genes and processes correlated to new collagen formation from gene expression analysis. Lung fibrosis was induced in female C57BL/6 mice by bleomycin instillation and sacrificed. Animals were sacrificed at 1 to 5 weeks after fibrosis induction. Collagen synthesized during the week before sacrifice was labelled with deuterium by providing mice with deuterated drinking water. After sacrifice, lung tissue was collected for microarray analysis, determination of new collagen formation, and histology. Deuterated water labelling showed a strong increase in new collagen formation already during the first week after fibrosis induction and a complete return to baseline at five weeks. Correlation of new collagen formation data with gene expression data revealed fibrosis specific processes, of which proliferation was an unexpected one. This was confirmed by measuring cell proliferation and collagen synthesis simultaneously using deuterated water incorporation. Furthermore, new collagen formation strongly correlated with gene expression of e.g. elastin, tenascin C, MMP-14, lysyl oxidase, and type V collagen. These data demonstrate, using a novel combination of technologies, that proliferation and extracellular matrix production are correlated to the core process of fibrosis, i.e. the formation of new collagen. In addition, it identified genes directly correlated to fibrosis, thus providing more insight into the aetiology of IPF. Total RNA was obtained from mouse lungs at timepoint 0 as a control (n = 7) or timepoints 1 (n = 7), 2 (n = 6), 3 (n = 6), 4 (n = 6) or 5 (n = 6) weeks after bleomycin-instillation to induce lung fibrosis.

Dataset Information

A conservative point mutation in a dynamic antigen-binding loop of human immunoglobulin λ6 light chain promotes pathologic amyloid formation

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure