Biology subjects

Cardus Figueras, A.

Publications and source records attributed to Cardus Figueras, A..

5 recordsLinked to original sources

bioRxiv2025

Discrete cytokine signaling networks instruct distinctsynovial pathotypes in inflammatory arthritis

Patients with rheumatoid arthritis (RA) display distinct patterns of synovitis. To define the inflammatory mechanisms driving this heterogeneity, we analyzed the inflamed synovium of wild-type (WT), Il6ra-/-, and Il27ra-/- mice with antigen-induced arthritis (AIA). Remarkably, each strain developed a joint pathology mirroring a major RA synovial pathotype: myeloid-rich (WT), fibroblast-rich/pauci-immune (Il6ra-/-), and lymphoid-rich (Il27ra-/-) synovitis. Histology confirmed minimal immune infiltration in Il6ra-/- joints, while WT and Il27ra-/- mice exhibited prominent immune involvement, including organized synovial lymphoid-like aggregates in Il27ra-/- mice. Transcriptomic and epigenomic profiling revealed both shared and distinct regulatory programs among genotypes. Il6ra-/- mice showed increased WNT, DKK, and AMPK signaling associated with fibroblast, chondrocyte, and osteoclast activation (e.g., Adamts19, Dkk1, Ecm1). Consistent with synovial ectopic lymphoid-like structures, Il27ra-/- mice showed enrichment of lymphocyte activation (e.g., Il17a, Il22, Bhlhe40). WT mice exhibited hallmarks of MAP kinase activation. These molecular signatures parallel those of fibroblast-, lymphoid-, and myeloid-rich synovitis in RA. Defining a STAT1-STAT3 regulatory interplay influencing transcriptional decisions in WT and Il27ra-/- mice, our findings offer insights into cytokine-driven disease heterogeneity. Together, these results establish a framework for mechanism-based classification of synovitis and introduce new mouse models to study the molecular drivers of synovial pathotypes and treatment response.

pathology↗

bioRxiv2025

Interleukin-6 elevates thrombosis via pro-coagulant phospholipids from platelet 12-lipoxygenase in rheumatoid arthritis.

BackgroundRheumatoid arthritis (RA) is associated with significantly higher thrombotic risk, which is not yet mechanistically understood. Here, the role of pro-coagulant membranes of platelets and blood cells in driving thrombosis, and their regulation by inflammation was determined using human cohorts and genetically-modified mice. MethodsAntigen-induced arthritis (AIA) was induced in WT, Il27ra-/-, Il6ra-/-, Alox12-/- and Alox15-/- mice. Coagulation and inflammatory markers were measured in plasma. Lipidomics was performed on blood cells and synovium analyzing pro-coagulant enzymatically-oxidized phospholipids (eoxPL) and oxylipins. Two human RA patient cohorts were characterized for eoxPL generation in blood cells, and chronic immune response to eoxPL in vivo. ResultsAIA induction significantly elevated plasma thrombin-antithrombin (TAT) complexes, serum amyloid A (SAA), and eoxPL in blood cells and platelets. Elevations in TATs, SAA and eoxPL were suppressed by genetic deletion of IL-6Ra, while platelet Alox12 deletion prevented TAT and eoxPL increases. This indicates a direct role for IL-6 in elevating thrombosis via upregulation of platelet eoxPL. In contrast, leukocyte Alox15 deletion did not impact TATs or eoxPL. Deletion of either LOX isoform worsened AIA joint pathology. Synovial tissue demonstrated raised eoxPL, but exclusively from Alox15, indicating leukocyte origin. Thus, both LOX isoforms contribute to AIA, but through different mechanisms. In human RA, platelet counts, and plasma TATs were elevated, and plasma had significantly elevated IgG against eoxPL, indicating patients experience chronic exposure to the lipids in vivo. ConclusionsPlatelet-derived pro-coagulant eoxPL are elevated in human and murine arthritis along with higher coagulation markers. In mice, this was mediated by the IL-6/Alox12 axis and directly responsible for the higher thrombotic risk. IL-6 plays a central role in driving platelet activation in RA, with the pro-coagulant lipid membrane representing a novel target. Reducing inflammation using DMARDs, particularly targeting IL-6 may reduce platelet pro-coagulant activity and thrombosis risk in RA.

pharmacology and toxicology↗

bioRxiv2025

12/15-Lipoxygenase orchestrates murine wound healing via PPARg-activating oxylipins acting holistically to dampen inflammation.

12/15-lipoxygenase (12/15-LOX, Alox15) generates bioactive oxygenated lipids during inflammation, however its homeostatic role(s) in normal healing are unclear. Here, the role of 12/15-LOX in resolving skin wounds was elucidated, focusing on how its lipids act together in physiologically relevant amounts. In mice, wounding caused acute appearance of 12/15-LOX-expressing macrophages and stem cells, coupled to early generation of [~]12 monohydroxy-oxylipins and enzymatically oxygenated phospholipids (eoxPL). Alox15 deletion increased -smooth muscle actin, collagen deposition, stem cell/fibroblast proliferation, IL6/pSTAT3, pSMAD3, and IFN-{gamma} levels. Conversely, CD206 expression, F480+ cells, MMP9 and MMP2 activities were reduced. Alox15-/- skin was deficient in PPAR{gamma}/adiponectin activity. Furthermore, while pro-inflammatory genes were upregulated as normal during wounding, many including Il6, Il1b, ccl4, Cd14, Cd274, Clec4d, Clec4e, Csf3, and Cxcl2 failed to revert to baseline during healing, indicating disruption of an anti-inflammatory brake. Reconstituting Alox15-/- wounds with a physiological mixture of Alox15-derived primary oxylipins generated by healing wounds restored MMP and dampened collagen deposition. The oxylipin mixture activated PPAR{gamma} in vitro, while in vivo, the PPAR{gamma} co-activator, Helz2, was significantly upregulated. Additional inflammatory and proliferative gene networks impacted by Alox15-/-included Elf4, Cebpb and Tcf3, with many of their associated genes significantly dysregulated. In summary, the impact of 12/15-LOX is ascribed to the deficiency of abundantly generated monohydroxy oxylipins acting together via PPAR{gamma}/adiponectin. The identification of multiple gene alterations reveals several new targets for treatment of non-healing wounds. Our studies demonstrate that abundant 12/15-LOX oxylipins act together, dampening inflammation in vivo, revealing a need to consider lipid signaling holistically. Significance statementDefective wound healing is a significant global clinical problem. Macrophage 12/15-lipoxygenase (12/15-LOX, Alox15) generates abundant lipid mediators termed oxylipins during inflammation. However, its physiological role during resolving wound healing is unclear, with studies so far assessing the bioactivity of individual lipids pharmacologically, rather than holistically in physiological amounts. Here, we report that Alox15 deficiency in mice caused a fibrotic response with failure to dampen inflammation, due to a dysregulated PPAR{gamma}/adiponectin axis. Treatment of Alox15-/- wounds with physiological mixtures of PPAR{gamma}-activating 12/15-LOX primary monohydroxy products restored the phenotype. Several transcriptional networks (Elf4, Cebpb and Tcf3) controlled by Alox15 were uncovered, identifying new targets for promoting physiological wound healing.

pharmacology and toxicology↗

bioRxiv2024

IL-6 and IL-27 negatively regulate CRTAM-expressing CD4+ T-cells associated with lymphoid-driven synovitis.

ABSTRACT-Joint pathology in rheumatoid arthritis is heterogeneous, with histology providing evidence of fibroblast-driven, myeloid-driven, and lymphoid-driven synovitis. However, the immuno-modulatory pathways underlying their development remain unclear. Profiling synovial tissues from rheumatoid arthritis patients and mice with antigen-induced arthritis, we identified a subset of synovial infiltrating CD4+ T-cells expressing CRTAM (class-I MHC-restricted T-cell-associated molecule). In human synovial biopsies, CRTAM correlated with the expression of effector cytokines (IL21, IFNG), chemokine receptors (CXCR3, CXCR4, CCR5), granzymes (GZMA, GZMB, GZMK), and regulatory factors (TIGIT, EOMES, BATF) linked with T-cell-mediated immunity. Studies of antigen-induced arthritis showed that CRTAM+CD4+ T-cells accumulate in the inflamed synovium following disease onset. CRTAM+CD4+ T-cells were particularly abundant in synovial tissue from Il27ra-/- mice displaying ectopic lymphoid-like structures. CADM1 (cell adhesion molecule-1), the endogenous ligand for CRTAM, was also expressed in human synovitis and synovial tissues from wild-type, Il6ra-/-, and Il27ra-/- mice with antigen-induced arthritis. Cells expressing human CADM1 included synovial fibroblasts and subsets of monocytic and CD19+ cells. Considering the ex vivo regulation of CRTAM, we identified that activation of naive CD4+ T-cell increased CRTAM expression. This induction was blocked by IL-6 and IL-27, with further studies identifying a role for STAT3 in controlling the CRTAM transcriptional repressor, ZEB1. These results provide insights into the cytokine control of CRTAM on CD4+ T-cells and support the involvement of CRTAM+CD4+ T-cells in lymphoid-driven synovitis.

immunology↗

bioRxiv2022

Effector Th1 cells alter the transcriptional output of IL-6 in acute resolving inflammation

Cytokines that signal via STAT1 and STAT3 transcription factors instruct decisions affecting tissue homeostasis, anti-microbial host defense, and inflammation-induced tissue injury. To understand the coordination of these activities, we applied RNA-seq, ChIP-seq, and ATAC-seq to identify the transcriptional output of STAT1 and STAT3 in peritoneal tissues during acute resolving inflammation and inflammation primed to drive fibrosis. Bioinformatics focussed on the transcriptional signature of the immuno-modulatory cytokine IL-6 in both settings and examined how pro-fibrotic IFN{gamma}-secreting CD4+ T-cells altered the interpretation of STAT1 and STAT3 cytokine cues. In resolving inflammation, STAT1 and STAT3 cooperated to drive stromal gene expression affecting anti-microbial immunity and tissue homeostasis. The introduction of IFN{gamma}-secreting CD4+ T-cells altered this transcriptional program and channeled STAT1 and STAT3 to a previously latent GAS motif in Alu-like elements. STAT1 and STAT3 binding to this conserved sequence revealed evidence of reciprocal cross-regulation and gene signatures relevant to pathophysiology. Thus, we propose that effector T-cells re-tune the transcriptional output of IL-6 by shaping a regulatory interplay between STAT1 and STAT3 in inflammation.

immunology↗