Regulation of Synovial Inflammation and Tissue Destruction by Guanylate Binding Protein 5 in Synovial Fibroblasts From Patients With Rheumatoid Arthritis and Rats With Adjuvant‐Induced Arthritis

Abstract

Objective. Rheumatoid arthritis synovial fibroblasts (RASFs) are crucial mediators of synovial inflammation and joint destruction. However, their intrinsic immunoregulatory mechanisms under chronic inflammation remain unclear. Thus, the present study was undertaken to understand the role of a newly identified GTPase, guanylate binding protein 5 (GBP-5), in RA pathogenesis.Methods. The expression of GBP1-GBP7 transcripts was evaluated using quantitative reverse transcriptionpolymerase chain reaction in RA synovial tissue or synovial tissue unaffected by RA. Our investigation on transient small interfering RNA (siRNA) knockdown and lentiviral overexpression in human RASFs examined the regulatory role of GBP-5 on proinflammatory cytokine signaling pathways. Unbiased whole transcriptome RNA sequencing analysis was used to assess the impact of GBP-5 on RASF molecular functions. These findings were confirmed using a rat model of adjuvant-induced arthritis (AIA) in vivo.Results. Among different GBPs evaluated, GBP-5 was selectively up-regulated in RA synovial tissue (P < 0.05; n = 4) and in the joints of rats with AIA (P < 0.05; n = 6) and was significantly induced in human RASFs by interleukin-1β (IL-1β), tumor necrosis factor (TNF), and/or interferon-γ (IFNγ) (P < 0.05; n = 3). Bioinformatics analysis of RNA sequencing data identified cytokine-cytokine receptor signaling as a major function altered by GBP-5, with IL-6 signaling as a primary target. Knockdown of GBP-5 amplified IL-1β-induced IL-6, IL-8, and epithelial neutrophilactivating peptide 78/CXCL5 production by 44%, 54%, 45%, respectively, and matrix metalloproteinase 1 (MMP-1) production by several-fold-effects that reversed with exogenously delivered GBP-5. Lack of GBP-5 increased IFNγ-induced proliferation and migration of human RASFs. GBP-5 knockdown in vivo using intraarticular siRNA exacerbated disease onset, severity, synovitis, and bone destruction in rat AIA.Conclusion. Expressed by RASFs in response to cytokine stimulation, GBP-5 has potential to restore cellular homeostasis and blunt inflammation and tissue destruction in RA.

Antioxidant glutathione inhibits inflammation in synovial fibroblasts via PTEN/PI3K/AKT pathway: An in vitro study

“…22 The MMPs produced from SFs usually contribute to the destruction of cartilage seen in RA. 23 The present RT-qPCR and ELISA results provided evidence that the levels of TNF-a and IL-6 were significantly decreased by GSH. However, we observed a higher level of IL-6 expression in LPS+GSH150 than that in LPS+GSH100.…”

Heilaohuacid G, a new triterpenoid from Kadsura coccinea inhibits proliferation, induces apoptosis, and ameliorates inflammation in RA‐FLS and RAW 264.7 cells via suppressing NF‐𝜅B pathway

“…MMPs are commonly released activated synovial fibroblast cells at the extracellular space (Sparks, 2019). According to researchers, both MMP‐1 and MMP‐3 are important in formation and progression of cartilage destruction and bone erosion in RA (Haque, Singh, Ouseph, & Ahmed, 2021). Therefore, modulating the function of RA‐FLS cells are considered as an effective therapeutic strategy for preventing destructive progress in RA.…”

Targeting MyD88 Downregulates Inflammatory Mediators and Pathogenic Processes in PBMC From DMARDs-Naïve Rheumatoid Arthritis Patients

“…MyD88 has also shown promising results by downregulating cytokines and chemokines and modulating LPS-induced mechanical hyperalgesia in the joint ( Guerrero et al, 2016 ). Several large-scale transcriptomic changes have been identified in different joint-resident cell types under IL-1β stimulation ( Gao et al, 2021 ; Haque et al, 2021 ). For this reason, inhibition of IL-1β and LPS signalling pathways is imperative.…”

“…The proinflammatory cytokine IL-1β, is among the critical mediators of inflammatory damage in RA. It exerts its activity via interaction with its receptors (IL-1R), which subsequently leads to the presentation of an intracellular Toll-IL-1-receptor (TIR) domain and activation of downstream signalling cascades that converge into large scale transcriptomic changes ( Migliorini et al, 2020 ; Haque et al, 2021 ). Myeloid Differentiation Primary Response 88 (Myd88) is a significant constituent of the signalling cascade downstream of IL-1β-IL-1R interaction, which ultimately converges with the canonical NF-κB signalling pathway leading to the further amplification of the inflammatory mediator production in RA ( Avbelj et al, 2011 ; Chen et al, 2020 ).…”