Osteoblastogenesis from synovial fluid-derived cells is related to the type and severity of juvenile idiopathic arthritis

Comprehensive Characterization of Th2/Th17 Cells-Related Gene in Systemic Juvenile Rheumatoid Arthritis: Evidence from Mendelian Randomization and Transcriptome Data Using Multiple Machine Learning Approaches

Background

Growing research has demonstrated that alterations in Th2 and Th17 cell composition were linked to systemic juvenile rheumatoid arthritis (sJRA). Nevertheless, whether these associations indicate a causal link remains unclear, and the potential effects of Th2/Th17-related molecules have not been clarified.

Methods

Mendelian randomization (MR) alongside transcriptome examination was implemented to ascertain the links between the Th2/Th17 cells and sJRA. Subsequently, we established an innovative machine learning (ML) framework encompassing 12 ML approaches and their 111 permutations to generate a unified Th2/Th17 classifier, which underwent verification across three separate cohorts. The hub Th2/Th17-related genes' level in the sJRA patients was substantiated via qRT-PCR. Lastly, the SHapley Additive exPlanations (SHAP) in conjunction with the XGBoost algorithm to pinpoint ideal Th2/Th17-linked genes.

Results

Based on MR analyses of two sJRA GWAS, 2 immunophenotypes (lymphocyte and IgD+ B cell) were causally linked to sJRA. Based on IOBR algorithms, we revealed that lymphocyte Th2/Th17 proportion was markedly changed in sJRA from seven cohorts. WGCNA and differential analysis in two merged GEO cohorts identified 64 Th2/Th17-related genes. Based on the average AUC (0.844) and model stability in four cohorts, we converted 12 ML techniques into 111 combinations, from which we chose the optimal algorithm to generate an ML-derived diagnostic signature (Th2/Th17 classifier). qRT-PCR verified results. Moreover, immune cell infiltration and functional enrichment analysis suggested hub Th2/Th17-related gene potentially mediated sJRA onset. XGBoost algorithm and SHAP detected HRH2 as crucial genetic markers, which may be an important target for sJRA.

Conclusion

A diagnostic model (Th2/Th17 classifier) via 111 ML algorithm combinations in six independent cohorts was generated and validated, which stands as an effective instrument for sJRA detection. The identification of essential immune components and molecular cascades, along with HRH2, could emerge as vital therapeutic targets for sJRA intervention, providing an enhanced understanding of its fundamental processes.

Secukinumab for children and adolescents with enthesitis-related arthritis and psoriatic arthritis: lessons from treatment in adults and the way forward

INTRODUCTION

Targeting IL-17A using Secukinumab, a humanized monoclonal immunoglobulin G1 (IgG1)/κ against IL-17A is a therapeutic option for immune-mediated disorders such as psoriasis and ankylosing spondylitis. The US Food and Drug Administration and the European Medicines Agency have approved it for the treatment of moderate to severe plaque psoriasis, active psoriatic arthritis, ankylosing spondylitis, and non-radiographic axial spondylarthritis. Recently it has also been approved for use in children with severe plaque psoriasis, active psoriatic arthritis, and enthesitis-related arthritis.

AREAS COVERED

This review focuses on the role of Secukinumab in the management of children and adolescents with enthesitis-related arthritis and psoriatic arthritis. We discuss the salient findings of pivotal RCTs and other studies supporting the use of Secukinumab in adults and children, in particular, focusing on its safety and efficacy.

EXPERT OPINION

Secukinumab is a therapeutic target for psoriasis, psoriatic arthritis, and spondyloarthropathies in both adults and children. No major safety signals are observed with its use in short-term follow-up. Thus far, Secukinumab has not been found to significantly increase the risk of tuberculosis (TB).

Reciprocal Alterations in Osteoprogenitor and Immune Cell Populations in Rheumatoid Synovia

Rheumatoid arthritis (RA) is chronic, autoimmune joint inflammation characterized by irreversible joint destruction. Besides increased resorption, destruction is a result of decreased bone formation, due to suppressed differentiation and function of the mesenchymal lineage-derived osteoblasts in inflammatory milieu. In this study, we analyzed the cellular composition of synovial tissue from 11 RA and 10 control patients harvested during planned surgeries in order to characterize resident synovial progenitor populations. Synovial cells were released by collagenase, and labeled for flow cytometry by two antibody panels: 1. CD3-FITC, CD14-PE, 7-AAD, CD11b-PECy7, CD235a-APC, CD19-APCeF780; and 2. 7-AAD, CD105-PECy7, CD45/CD31/CD235a-APC, and CD200-APCeF780. The proportions of lymphocytes (CD3⁺, CD19⁺) and myeloid (CD11b⁺, CD14⁺) cells were higher in synovial tissue from the patients with RA than in the controls. Among non-hematopoietic (CD45^-CD31^-CD235a^-) cells, there was a decrease in the proportion of CD200⁺CD105^- and increase in the proportion of CD200^-CD105⁺ cells in synovial tissue from the patients with RA in comparison to the control patients. The proportions of both populations were associated with inflammatory activity and could discriminate between the RA and the controls.

Synovial fluid mesenchymal progenitor cells from patients with juvenile idiopathic arthritis demonstrate limited self-renewal and chondrogenesis

Juvenile idiopathic arthritis (JIA) is a heterogeneous group of inflammatory diseases affecting joints with a prevalence of one in a thousand children. There is a growing body of literature examining the use of mesenchymal stem/progenitor cells (MPCs) for the treatment of adult and childhood arthritis, however, we still lack a clear understanding of how these MPC populations are impacted by arthritic disease states and how this could influence treatment efficacy. In the current study we examined the immunophenotyping, self-renewal ability and chondrogenic capacity (in vitro and in vivo) of synovial derived MPCs from normal, JIA and RA joints. Synovial MPCs from JIA patients demonstrated reduced self-renewal ability and chondrogenic differentiation capacity. Furthermore, they did not induce cartilage regeneration when xenotransplanted in a mouse cartilage injury model. Synovial MPCs from JIA patients are functionally compromised compared to MPCs from normal and/or RA joints. The molecular mechanisms behind this loss of function remain elusive. Further study is required to see if these cells can be re-functionalized and used in cell therapy strategies for these JIA patients, or if allogenic approaches should be considered.

Analysis of Earlier Temporomandibular Joint Disorders in JIA Patients: A Clinical Report

The aim of this study was to analyse the structural characteristics of the temporo-mandibular joint (TMJ) and the dysfunctional consequences induced by disease in subjects with juvenile idiopathic arthritis (JIA). The study was conducted in 25 patients with JIA (median age (IQR), 13.9 (10.9-15.3)) and 26 healthy controls (median age (IQR), 14.3 (11.6-17.2)) years. All enrolled patients were subjected to anamnestic evaluation, laboratory parameters, JIA subclass, and type of therapy for the disease. A clinical-gnathological evaluation, anamnestic and dysfunctional index (Ai and Di), and magnetic resonance imaging of TMJs were performed in all patients. The test group showed a significant reduction (p < 0.001) regarding the clinical findings such as maximal mouth opening, left and rightward laterotrusion and protrusion, and a significant difference in the reported symptoms (TMJ sounds, reduced mouth opening and pain), and Ai and Di (p < 0.001) compared to healthy patients. Correlation analysis showed a significant correlation between the median duration of disease and the maximum mouth opening and between visual analogue scale (VAS) score and maximum mouth opening, leftward laterotrusion, rightward laterotrusion, and protrusion. The results obtained in this study suggest that patients with JIA presented a cohort of symptoms in TMJs in comparison with healthy controls. Moreover, a careful TMJs evaluation and an early diagnosis of TMJs dysfunction and regular follow-ups are recommended in order to prevent and reduce functional and chewing problems in patients with JIA.

Combination of polyetherketoneketone scaffold and human mesenchymal stem cells from temporomandibular joint synovial fluid enhances bone regeneration

Therapies using human mesenchymal stem cells (MSCs) combined with three-dimensional (3D) printed scaffolds are a promising strategy for bone grafting. But the harvest of MSCs still remains invasive for patients. Human synovial fluid MSCs (hSF-MSCs), which can be obtained by a minimally invasive needle-aspiration procedure, have been used for cartilage repair. However, little is known of hSF-MSCs in bone regeneration. Polyetherketoneketone (PEKK) is an attractive bone scaffold due to its mechanical properties comparable to bone. In this study, 3D-printed PEKK scaffolds were fabricated using laser sintering technique. hSF-MSCs were characterized and cultured on PEKK to evaluate their cell attachment, proliferation, and osteogenic potential. Rabbit calvarial critical-sized bone defects were created to test the bone regenerative effect of PEKK with hSF-MSCs. In vitro results showed that hSF-MSCs attached, proliferated, and were osteogenic on PEKK. In vivo results indicated that PEKK seeded with hSF-MSCs regenerated twice the amount of newly formed bone when compared to PEKK seeded with osteogenically-induced hSF-MSCs or PEKK scaffolds alone. These results suggested that there was no need to induce hSF-MSCs into osteoblasts prior to their transplantations in vivo. In conclusion, the combined use of PEKK and hSF-MSCs was effective in regenerating critical-sized bone defects.

Fas receptor induces apoptosis of synovial bone and cartilage progenitor populations and promotes bone loss in antigen-induced arthritis

Rheumatoid arthritis (RA) is an inflammatory joint disease that eventually leads to permanent bone and cartilage destruction. Fas has already been established as the regulator of inflammation in RA, but its role in bone formation under arthritic conditions is not completely defined. The aim of this study was to assess the effect of Fas inactivation on the bone damage during murine antigen-induced arthritis. Subchondral bone of wild-type (WT) and Fas-knockout (Fas^-/-) mice was evaluated by histomorphometry and microcomputerized tomography. Proportions of synovial bone and cartilage progenitors were assessed by flow cytometry. Synovial bone and cartilage progenitors were purified by fluorescence-activated cell sorting and expression of Fas and Fas-induced apoptosis were analyzed in vitro. Results showed that Fas^-/- mice developed attenuated arthritis characterized by preserved epiphyseal bone and cartilage. A proportion of the earliest CD200⁺ bone and cartilage progenitors was reduced in WT mice with arthritis and was unaltered in Fas^-/- mice. During osteoblastic differentiation in vitro, CD200⁺ cells express the highest levels of Fas and are removed by Fas ligation. These results suggest that Fas-induced apoptosis of early CD200⁺ osteoprogenitor population represents potential mechanism underlying the impaired bone formation in arthritis, so their preservation may represent the bone-protective mechanism during arthritis.-Lazić Mosler, E., Lukač, N., Flegar, D., Fadljević, M., Radanović, I., Cvija, H., Kelava, T., Ivčević, S., Šućur, A., Markotić, A., Katavić, V., Marušić, A., Grčević, D., Kovačić, N. Fas receptor induces apoptosis of synovial bone and cartilage progenitor populations and promotes bone loss in antigen-induced arthritis.

Interleukin-17A Levels Increase in Serum of Children With Juvenile Idiopathic Arthritis

Objectives

This study aims to determine the serum levels of interleukin-17A (IL-17A) in children with juvenile idiopathic arthritis (JIA) and analyze the correlation between IL-17A values and disease activity, certain clinical features, and laboratory markers of inflammation.

Patients and methods

The study included 30 children (7 boys, 23 girls; mean age 8.8±5.3 years; range 1 to 18 years), who had been diagnosed with JIA (18 children were diagnosed during the study period and 12 children were diagnosed before the start of the study) and had active disease during the study period. Control group included 30 healthy, age- and sex- matched children (9 boys, 21 girls; mean age 8.3±4.8 years; range 1 to 18 years). The enzyme-linked immunosorbent assay was used to assess the serum IL-17A levels of children with JIA in the active phase of the disease and control group. Clinical and laboratory features of the disease were evaluated for the children with JIA.

Results

Serum levels of IL-17A in children with JIA were significantly higher in comparison to control group. In children with JIA who were prospectively monitored, statistically significantly decreased IL-17A level was recorded in the inactive phase of the disease. The incidence of arthritis of coxofemoral joints was significantly more common, and the mean levels of erythrocyte sedimentation rate and C-reactive protein were significantly higher in the group of children with JIA with detectable levels of IL-17A. Children with JIA and detectable levels of IL-17A had significantly higher values of Juvenile Arthritis Disease Activity Score-27 in comparison to children with JIA and non-detectable IL-17A.

Conclusion

Assessment of serum IL-17A levels in early phases of JIA gives an opportunity for early detection of children that have higher risk for worse functional outcome.