A specific anti-citrullinated protein antibody profile identifies a group of rheumatoid arthritis patients with a toll-like receptor 4-mediated disease

Abstract

BackgroundIncreased expression of toll-like receptor 4 (TLR4) and its endogenous ligands, is characteristic of rheumatoid arthritis (RA) synovitis. In this study, we evaluated how these TLR4 ligands may drive pathogenic processes and whether the fine profiling of anti-citrullinated protein antibodies (ACPA) based on their target specificity might provide a simple means to predict therapeutic benefit when neutralizing TLR4 in this disease.MethodsThe capacity of RA synovial fluids (RASF) to stimulate cytokine production in monocytes from patients with RA was analyzed by ELISA. The presence of TLR4 activators in RASF was determined by measuring the levels of ACPA, ACPA subtypes with reactivity to specific citrullinated peptides and other TLR4 ligands. Neutralization of TLR4 signaling was investigated using NI-0101, a therapeutic antibody that targets TLR4.ResultsRASF exhibited a heterogeneous capacity to induce production of proinflammatory cytokines by monocytes isolated from patients with RA. Such cytokine responses were significantly modified by TLR4 blockade achieved using NI-0101. The analysis of the content of RASF and matched sera demonstrated that ACPA fine specificities in patient samples predict cellular response to anti-TLR4 exposure in vitro.ConclusionTLR4 represents a possible therapeutic target in RA. Our study demonstrates that TLR4 inhibition in an ex vivo model of RA pathogenesis can significantly modulate cytokine release and does so in specific subgroups of RA patient-derived samples. It also suggests that ACPA fine profiling has the potential to identify RA patients with a predominantly TLR4-driven pathotype that could be used to predict preferential response to TLR4 antagonism.Electronic supplementary materialThe online version of this article (doi:10.1186/s13075-016-1128-5) contains supplementary material, which is available to authorized users.

Affinity Maturation Drives Epitope Spreading and Generation of Proinflammatory Anti–Citrullinated Protein Antibodies in Rheumatoid Arthritis

“…Importantly, differentially evolved ACPAs observed at later time points formed ICs that more potently stimulated macrophage TNF production, highlighting the potential for an increased pathogenic role of these affinity-matured ACPAs. The level of TNF produced by IC stimulation of macrophages was reduced by TLR-4 blockade, thus demonstrating the potential of TLR-4 as a therapeutic target in RA, as has been suggested previously (16,17,48,49). Taken together, our findings demonstrate that affinity maturation plays a critical role in epitope spreading and generation of ACPAs that more potently drive macrophage TNF production in RA.…”

Association of Distinct Fine Specificities of Anti−Citrullinated Peptide Antibodies With Elevated Immune Responses to Prevotella intermedia in a Subgroup of Patients With Rheumatoid Arthritis and Periodontitis

“…In GCF, citrullinated peptides were detected in samples from patients with both PD and RA, but also in samples from patients with RA or PD alone, and in samples from healthy controls. A number of the citrullinated sites that we identified in this study have previously been identified in RA synovial tissue or fluid, and demonstrated to act as autoantigen epitopes, including R35 in fibrinogen α , R715 in α 2 ‐macroglobulin, R450 and R304 in vimentin, R93 in histone H2B type 2‐E , R4 in histone 2A , as well as R69 and R71 in vimentin . We also detected citrullinated peptides in GCF and periodontal tissues that have not been described as autoantigens in RA.…”

“…Notably, a number of citrullinated residues that we detected in periodontal samples have previously been identified in synovial fluid from RA patients (R35 in fibrinogen α [32], R715 in α 2 ‐macroglobulin, R450 and R304 in vimentin, and R93 in histone H2B type 2‐E [33]). In addition, we detected peptides with citrullinated residues at position R4 in histone 2A as well as at positions R69 and R71 in vimentin, that are described as autoantibody targets in RA . Citrulline 71 in vimentin was also recently detected in lung tissue samples, including those from smokers and patients with chronic obstructive pulmonary disease .…”

Toll-like receptors activation, signaling, and targeting: an overview

“…NI-0101, an anti-TLR4 antibody, can inhibit TLR4 signaling by blocking TLR4 dimerization (Monnet et al, 2015). It could successfully block cytokine release ex vivo and in vivo, prevent LPS-induced flu-like symptoms (Monnet et al, 2017), and block synovial fluids-induced pro-inflammatory cytokine production in monocytes isolated from RA patients (Hatterer et al, 2016). 1A6, another TLR4-antibody, has shown to target TLR4 activation (Spiller et al, 2008), ameliorate inflammation, and prevent the disease progression in a mouse model of colitis and protect against microbial-induced septic shock in vivo (Lima et al, 2015).…”