New structural insights into the role of TROVE2 complexes in the on-set and pathogenesis of systemic lupus erythematosus determined by a combination of QCM-D and DPI

Abstract

The mechanism of self-recognition of the autoantigen TROVE2, a common biomarker in autoimmune diseases, has been studied with Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) and Dual Polarization Interferometry (DPI). The complementarity and remarkable analytical features of both techniques has allowed to achieve new insights onto the onset of systemic Lupus Erythematosus (SLE) at the molecular level. The in vitro study for SLE patients and healthy subjects suggests that anti-TROVE2 autoantibodies may undergo an antibody bipolar bridging. An epitope-paratope specific binding initially occurs to activate a hidden Fc-receptor in the TROVE2 tertiary structure. This bipolar mechanism may contribute to the pathogenic accumulation of anti-TROVE2 autoantibody immune complex in autoimmune disease. Furthermore, the specific calcium dependent protein-protein bridges point out at how the TRIM21:TROVE2 association might occur, suggesting that the TROVE2 protein could stimulate the intracellular immune signaling via the TRIM21 PRY-SPRY domain. These findings may help to better understand the origins of the specificity and affinity of TROVE2 interactions, which might play a key role in the SLE pathogenesis. This manuscript gives one of the first practical applications of two novel functions (df/dD and h/molec) for the analysis of the data provided by QCM-D and DPI. In addition, it is the first time that QCM-D has been used for mapping hidden Fc-receptors as well as linear epitopes in a protein tertiary structure.

Biomacromolecular Characterizations Using State-of-the-Art Quartz Crystal Microbalance with Dissipation

“…Conformational dynamics and allosteric changes are essential for proteins’ function. Using QCM-D, Juste-Dolz et al systematically studied the conformational changes and interactions of relevant proteins during the onset of systemic lupus erythematosus (SLE), an autoimmune disease. As shown in Figure A, QCM-D and dual polarization interferometry (DPI) analyses provide two novel functions ( − Δ f / Δ D and Δ h / mole ) important for the in situ monitoring of the structural transitions and the reaction pathways.…”

“…(A) Response of the TROVE2-based biosensors in terms of − ∂ f ∂ D ratio for IgG from sera of SLE patients (upper) and DPI values (lower) of thickness per molecule monitored during the hIgGs/TROVE2 biorecognition for SLE patients; (B) QCM-D characterization of the conformational change, calcium ion selectivity, competition, and recognition of the protein–protein interaction involving TROVE2 and TRIM21. Adapted with permission from ref . Copyright 2018 Springer Nature.…”

“…51 Conformational dynamics and allosteric changes are essential for proteins' function. Using QCM-D, Juste-Dolz et al 52 systematically studied the conformational changes and interactions of relevant proteins during the onset of systemic lupus erythematosus (SLE), an autoimmune disease. As shown in Figure 6A, QCM-D and dual polarization interferometry (DPI) analyses provide two novel functions ( f D / and h/mole) important for the in situ monitoring of the structural The analytic method in this study is practically important for understanding the deeply hidden information such as linear epitopes in a protein tertiary structure and the pathogenic nature of TROVE2, which may be helpful for therapeutic intervention.…”

Recent applications of QCM-D for the design, synthesis, and characterization of bioactive materials

“…Solvent content/desolvation 25,26 Layer-by-layer deposition 29 Competitive adsorption 30 Protein structure/orientation [31][32][33] Mechanical properties 35 Antigen binding mechanisms 36…”

“…Juste-Dolz et al used a novel QCM-D assay to assess the binding mechanism of antibodies against the autoantigen TROVE2 (a common biomarker in autoimmune disease). 36 By analyzing structural changes after QCM-D sensor binding they determined that anti-TROVE2 antibodies can bind to two regions of the TROVE2 autoantigen in a "bipolar bridging." They noted that this binding mechanism likely mediates the pathogenesis of systemic lupus erythematosus at the molecular level by aggregating protein complexes and restricting apoptotic cell clearance.…”