CXCR3 antagonist NBI-74330 mitigates joint inflammation in Collagen-Induced arthritis model in DBA/1J mice

Increased seizure susceptibility in the collagen-induced arthritis mouse model depends on neuronal IL-1R1

AIMS

Numerous clinical studies have revealed a positive correlation between rheumatoid arthritis (RA) and an elevated risk of epilepsy. This study aimed to investigate the seizure susceptibility in the collagen-induced arthritis (CIA) mice model.

MAIN METHODS

The classic CIA model was used to mimic RA pathogenesis in mice. The pentylenetetrazole (PTZ)-induced seizure model and audiogenic seizure model were used to evaluate seizure susceptibility. Neuroinflammation was assessed through ELISA, Western blot, and immunofluorescence staining. Additionally, electrophysiological techniques were applied to investigate the excitation/inhibition (E/I) balance.

KEY FINDINGS

CIA modeling raised the level of IL-1β, induced E/I imbalance in the dentate gyrus (DG) region, and enhanced seizure susceptibility to PTZ in C57BL/6 mice. However, knockout (KO) of IL-1β attenuated peripheral inflammatory symptoms and blocked the increase in seizure susceptibility in CIA-modeled mice. Additionally, conditional IL-1R1 KO in CaMKIIα-positive neurons did not affect the peripheral inflammatory symptoms but rescued both the increased seizure susceptibility and E/I imbalance in CIA-modeled mice. Furthermore, increased susceptibility to audiogenic seizure susceptibility was also observed in CIA-modeled BDA/1 mice, accompanied by the elevated IL-1β levels and neuronal IL-1R1-related Akt phosphorylation in the hippocampus.

SIGNIFICANCE

Increased seizure susceptibility in the CIA mouse model depends on IL-1β and neuronal IL-1R1. These data indicated that IL-1β and neuronal IL-1R1 may be the key targets for its intervention.

Understanding the pleiotropic effects of CXCL10/IP-10 in the immunopathogenesis of inflammatory rheumatic diseases: Implications for better understanding disease mechanisms

Chemokines play a critical role in immune responses, acting as chemotactic factors and effectors in different immune processes. CXCL10/IFN-gamma-inducible protein 10 (IP-10) is an inflammatory chemokine that regulates immune cell activation and recruitment by binding to its receptor CXCR3. Additionally, CXCL10 inhibits angiogenesis by interacting with endothelial cells (ECs). In the context of inflammatory rheumatic diseases, CXCL10 influences multiple pathways including chemotaxis, angiostasis, bone destruction, joint inflammation, and regulation of fibroblast-like synoviocyte properties. High levels of CXCL10 have been detected in the serum and tissues of individuals with autoimmune conditions like systemic sclerosis (SSc), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and among others (ankylosing spondylitis, Behçet's syndrome). The CXCL10 may inhibit fibroblast recruitment after tissue injury, delaying wound healing; inhibiting angiogenesis, and uncontrolled pulmonary fibrosis in SSc. In RA disease, the CXCL10-CXCR3 axis could increase the inflammatory cell infiltration, including T lymphocytes and macrophages, into inflamed joints, enhancing arthritis severity and bone and cartilage destruction. The interaction between CXCR3 and ligand-CXCL10 on directing the CD4+ T lymphocytes polarization and observed that CXCL10 skew T lymphocytes polarization into Th1/Th17 effector cells that could lead to an increase in the inflammatory responses in the SLE. This study aims to explore the role of CXCL10 in rheumatic diseases and its potential as both a therapeutic target and a biomarker for these conditions. Understanding the involvement of CXCL10 in the immunopathogenesis of inflammatory rheumatic diseases may provide valuable insights for the development of targeted therapies and diagnostic strategies.

CXCR3 inhibition ameliorates mitochondrial function to mitigate oxidative damage through NCOA4-mediated ferritinophagy and improves the gut microbiota in mice

Nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy contributes to maintain intracellular iron balance by regulating ferritin degradation, which is essential for redox homeostasis. CXC-motif chemokine receptor 3 (CXCR3) is involved in the regulation of oxidative stress and autophagy. However, its role in modulating intestinal oxidative damage through ferritinophagy and the gut microbiota remains unclear. In this study, the impacts of CXCR3 inhibition on intestine oxidative damage, ferritinophagy, and the gut microbiota, as well as the mitochondrial quality control were investigated both in vivo and in vitro. The results show that CXCR3 inhibition by AMG487 relieves Diquat-induced intestinal damage, enhances the expression of tight junction proteins, and promotes antioxidant capacity in mice. Simultaneously, CXCR3 inhibition improves gut microbiota composition, and triggers NCOA4-mediated ferritinophagy. Mechanistically, the effects of CXCR3 inhibition on ferritinophagy were explored in IPEC-J2 cells. Co-localization and interaction between CXCR3 and NCOA4 were observed. Downregulation of NCOA4-mediated ferritinophagy leads to increase the expression of tight junction proteins, reduces iron levels, restricts ROS accumulation, and enhances GPX4 expression. Moreover, CXCR3 suppression facilitates mitochondrial biogenesis and mitochondrial fusion, increases antioxidative capacity, and results in the elevation of tight junction proteins expression. These findings suggest that CXCR3 inhibition reverses Diquat-induced intestinal oxidative damage, enhances mitochondrial function, and improves gut microbiota composition by elevating NCOA4-mediated ferritinophagy, which implies that CXCR3 may serve as a potential therapeutic intervention targeting iron metabolism for treating intestinal diseases.

An analysis of single-cell data reveals therapeutic effects of AMG487 in experimental autoimmune uveitis

Uveitis, an ocular autoimmune disease that poses a significant threat to vision, is caused by immune cells erroneously attacking retinal cells and currently lacks specific and effective therapeutic interventions. The CXC chemokine receptor 3 (CXCR3) facilitates the migration of immune cells to sites of inflammation. AMG487, a CXCR3 antagonist, holds potential for treating autoimmune diseases by blocking immunes cells chemotaxis. However, its effects and mechanisms in uveitis remain unclear. Using single-cell assay for transposase-accessible chromatin sequencing and RNA sequencing, we observed increased expression of CXCR3 and chemotactic pathways in peripheral blood of Vogt-Koyanagi-Harada patients and cervical lymph nodes of experimental autoimmune uveitis mice. AMG487 treatment in experimental autoimmune uveitis was shown to be therapeutically effective. Analysis of flow cytometry and single-cell RNA sequencing in AMG487-treated mice revealed reduced expression of inflammatory genes in immune cells. Specifically, AMG487 decreased the proportion of plasma cell in B cells, restored the ratio between effector T cells and regulatory T cells, and diminished T helper (Th) 17 cell pathogenicity by suppressing highly inflammatory granulocyte-macrophage colony-stimulating factor-producing Th17 cells while enhancing anti-inflammatory interleukin-10-producing Th17 cells. Our study presents an exhaustive single-cell transcriptional analysis of immune cells under AMG487 treatment, thereby elucidating potential mechanisms and providing a potential reference for the development of novel therapeutic strategies for autoimmune diseases.

Genetics, epigenetics and autoimmunity constitute a Bermuda triangle for the pathogenesis of rheumatoid arthritis

Rheumatoid arthritis (RA), a multigene disorder with a heritability rate of 60 %, is characterized by persistent pain, synovial hyperplasia, and cartilage and bone destruction, ultimately causing irreversible joint deformity. The etiology and pathogenesis of rheumatoid arthritis (RA) are primarily influenced by specific genetic variants, particularly HLA alleles such as HLA-DRB1*01 and DRB1*04. However, other HLA alleles such as HLA-DRB1*10 and DPB*1 have also been found to contribute to increased susceptibility to RA. However, non-HLA genes also confer a comparatively high risk of RA disease manifestation. The most relevant single nucleotide polymorphisms (SNPs) associated with non-HLA genes are PTPN22, TRAF1, CXCL-12, TBX-5, STAT4, FCGR, PADI4, and MTHFR. In conjunction with genetic susceptibility, epigenetic alterations orchestrate paramount involvement in regulating RA pathogenesis. Increasing evidence implicates DNA methylation and histone protein modifications, including acetylation and methylation, as the primary epigenetic mechanisms that drive the pathogenesis and clinical progression of the disease. In addition to genetic and epigenetic changes, autoimmune inflammation also determines the pathological progression of the synovial membrane in joints with RA. Glycosylation changes, such as sialylation and fucosylation, in immune cells have been shown to be relevant to disease progression. Genetic heterogeneity, epigenetic factors, and changes in glycosylation do not fully explain the features of RA. Therefore, investigating the interplay between genetics, epigenetics, and autoimmunity is crucial. This review highlights the significance and interaction of these elements in RA pathophysiology, suggesting their diagnostic potential and opening new avenues for novel therapeutic approaches.

The role of Th/Treg immune cells in osteoarthritis

Osteoarthritis (OA) is a prevalent clinical condition affecting the entire joint, characterized by its multifactorial etiology and complex pathophysiology. The onset of OA is linked to inflammatory mediators produced by the synovium, cartilage, and subchondral bone, all of which are closely tied to cartilage degradation. Consequently, OA may also be viewed as a systemic inflammatory disorder. Emerging studies have underscored the significance of T cells in the development of OA. Notably, imbalances in Th1/Th2 and Th17/Treg immune cells may play a crucial role in the pathogenesis of OA. This review aims to compile recent advancements in understanding the role of T cells and their Th/Treg subsets in OA, examines the immune alterations and contributions of Th/Treg cells to OA progression, and proposes novel directions for future research, including potential therapeutic strategies for OA.

Mechanistic role of quercetin as inhibitor for adenosine deaminase enzyme in rheumatoid arthritis: systematic review

Rheumatoid arthritis (RA) is an autoimmune disease involving T and B lymphocytes. Autoantibodies contribute to joint deterioration and worsening symptoms. Adenosine deaminase (ADA), an enzyme in purine metabolism, influences adenosine levels and joint inflammation. Inhibiting ADA could impact RA progression. Intracellular ATP breakdown generates adenosine, which increases in hypoxic and inflammatory conditions. Lymphocytes with ADA play a role in RA. Inhibiting lymphocytic ADA activity has an immune-regulatory effect. Synovial fluid levels of ADA are closely associated with the disease's systemic activity, making it a useful parameter for evaluating joint inflammation. Flavonoids, such as quercetin (QUE), are natural substances that can inhibit ADA activity. QUE demonstrates immune-regulatory effects and restores T-cell homeostasis, making it a promising candidate for RA therapy. In this review, we will explore the impact of QUE in suppressing ADA and reducing produced the inflammation in RA, including preclinical investigations and clinical trials.

Association Between Serum Chemokine Ligand 20 Levels and Disease Activity and Th1/Th2/Th17-Related Cytokine Levels in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a type of arthritis autoimmune disease characterized by systemic chronic inflammation. C-C Chemokine ligand 20 (CCL20) is the same as most chemokines with immunomodulatory and inflammatory processes. The correlation of CCL20 in RA remains unclear. This study aimed to explore the association among levels of CCL20, T helper cell (TH) subset (Th1/Th2/Th17)-related cytokine levels, and clinical indices of RA disease activity. Serum CCL20 levels were quantified by enzyme-linked immunosorbent assay, and a flow-fluorescence technique was used to assess Th1/Th2/Th17-related cytokine levels. The serum CCL20 levels in patients were significantly higher than those in healthy controls and positively associated with C-reactive protein levels, erythrocyte sedimentation rate, and disease activity score-28 (DAS28). Patients with RA were categorized into 4 major groups, including remission, low, moderate, and high disease activity, with related DAS28 scores for each group. CCL20 levels of the disease moderate/high activity group were moderately positively correlated with IL-6 levels, but not with the other Th1/Th2/Th17-related cytokines. Serum CCL20 levels correlate strongly with RA disease activity and clinical inflammation and were significantly elevated in patients compared to healthy individuals. CCL20 plays a key role in the immune response of patients with RA and is, therefore, a potential biomarker of disease activity.