Exploration and validation of therapeutic molecules for rheumatoid arthritis based on ferroptosis-related genes.

AIMS: This study aimed to identify hub ferroptosis-related genes (FRGs) and investigate potential therapy for RA based on FRGs. MAIN METHODS: The differentially expressed FRGs in synovial tissue of RA patients were obtained from the dataset GSE12021 (GPL96). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were conducted to investigate the potential signaling pathways associated with FRGs. Hub genes were identified through topological analysis. The expression levels of these hub genes as well as their diagnostic accuracies were further evaluated. Connectivity Map (CMap) database was utilized to analyze the top 10 FRGs-guided potential drugs for RA. In vitro and in vivo experiments were carried out for further validation. KEY FINDINGS: 2 hub genes among 58 FRGs were identified (EGR1 and CDKN1A), and both were down regulated in RA synovial tissue. GPx4 expression was also decreased in the RA synovial tissue. The natural compound withaferin-a exhibited the highest negative CMap score. In-vitro and in-vivo experiments demonstrated anti-arthritic effects of withaferin-a. SIGNIFICANCE: Ferroptosis participates in pathogenesis of RA, ferroptosis-related genes EGR1 and CDKN1A can be used as diagnostic and therapeutic targets for RA. Withaferin-a can be used as potential anti-arthritic treatment.

Peroxiredoxin 4 regulates tumor-cell-like characteristics of fibroblast-like synoviocytes in rheumatoid arthritis through PI3k/Akt signaling pathway.

Peroxiredoxin-4 (PRDX4), a member of PRDX family, which played an important role in scavenging reactive oxygen species (ROS). The up-regulation of PRDX4 in synovial tissue and synovial fluid from rheumatoid arthritis (RA) patients has been reported. However, the biological functions of PRDX4 in fibroblast-like synoviocytes (RA-FLS) remains unclear. In this research, we reveal that expression of PRDX4 was notably increased in RA synovial tissue, especially in hyperplastic synovial tissue. PRDX4 silencing significantly inhibited the tumor cell-like behaviors and mRNA expression of matrix metalloproteinases (MMPs) in RA-FLS. Furthermore, overexpression of PRDX4 markedly activated PI3K/Akt signaling pathway, which can be reverted by Akt inhibitor MK-2206. These observations identified elevated PRDX4 may regulates the tumor cell-like biological characteristic of RA-FLS via Pi3k/Akt pathway. Targeting PRDX4 and its downstream signaling pathway might provide a potential diagnostic markers and therapeutic target for RA.

Therapeutic Effects of Naringin in Rheumatoid Arthritis: Network Pharmacology and Experimental Validation.

Rheumatoid arthritis is a chronic autoimmune disease characterized by persistent hyperplasia of the synovial membrane and progressive erosion of articular cartilage. Disequilibrium between the proliferation and death of RA fibroblast-like synoviocytes (RA-FLSs) is the critical factor in progression of RA. Naringin has been reported to exert anti-inflammatory and antioxidant effect in acute and chronic animal models of RA. However, the therapeutic effect and underlying mechanisms of naringin in human RA-FLS remain unclear. Based on network pharmacology, the corresponding targets of naringin were identified using SwissTargetPrediction database, STITCH database, and Comparative Toxicogenomics Database. Deferentially expressed genes (DEGs) in RA were obtained from the GEO database. The protein-protein interaction (PPI) networks of intersected targets were constructed using the STRING database and visualized using Cytoscape. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed, and the pathways directly related to pathogenesis of RA were integrated manually. Further, in vitro studies were carried out based on network pharmacology. 99 target genes were intersected between targets of naringin and DEGs. The PPI network and topological analysis indicated that IL-6, MAPK8, MMP-9, TNF, and MAPK1 shared the highest centrality among all. GO analysis and KEGG analysis indicated that target genes were mostly enriched in (hsa05200) pathways in cancer, (hsa05161) hepatitis B, (hsa04380) osteoclast differentiation, (hsa04151) PI3K-Akt signaling pathway, and (hsa05142) Chagas disease (American trypanosomiasis). In vitro studies revealed that naringin exposure was found to promote apoptosis of RA-FLS, increased the activation of caspase-3, and increased the ratio of Bax/Bcl-2 in a dose-dependent manner. Furthermore, treatment of naringin attenuated the production of inflammatory cytokines and matrix metalloproteinases (MMPs) in TNF-ɑ-induced RA-FLS. Moreover, treatment of naringin inhibited the phosphorylation of Akt and ERK in RA-FLS. Network pharmacology provides a predicative strategy to investigate the therapeutic effects and mechanisms of herbs and compounds. Naringin inhibits inflammation and MMPs production and promotes apoptosis in RA-FLS via PI3K/Akt and MAPK/ERK signaling pathways.

Identification of pivotal genes and pathways in the synovial tissue of patients with rheumatoid arthritis and osteoarthritis through integrated bioinformatic analysis.

Rheumatoid arthritis (RA) and osteoarthritis (OA) are the two most common debilitating joint disorders and although both share similar clinical manifestations, the pathogenesis of each is different and remains relatively unclear. The present study aimed to use bioinformatic analysis to identify pivotal genes and pathways involved in the pathogenesis of RA. Microarray datasets from patients with RA and OA were obtained from the Gene Expression Omnibus (GEO) database and differentially expressed genes (DEGs) were identified using GEO2R software; Gene Ontology analysis and pathway enrichment were analyzed using the Database for Annotation, Visualization and Integrated Discovery and the Kyoto Encylopedia for Genes and Genomes, respectively; and protein­protein interaction networks of DEGs were constructed using the Search Tool for the Retrieval of Interacting Genes database, and module analysis and pathway crosstalk of the PPI network was visualized using plugins of Cytoscape. In addition, the prediction of target mRNAs for differentially expressed microRNAs (DEMs) was performing using the starBase database and the identified pivotal genes were verified using reverse­transcription quantitative PCR in synovial tissue from patients with RA. A total of 566 DEGs were identified in GSE55457, GSE55235 while 23 DEMs were identified in the GSE72564 dataset. Upregulated DEGs were found to be mostly enriched in the 'Cytokine­cytokine receptor interaction' pathway, whereas downregulated DEGs were discovered to be enriched in the 'PPAR signaling pathway'. The top 25 DEGs were mostly enriched in the 'Chemokine signaling pathway'. In addition, six of the miRNA target genes were selected as potential biomarkers and a total of 24 genes were selected as potential hub genes. Experimental validation demonstrated that the expression levels of Cytotoxic T­Lymphocyte Associated Protein 4 (CTLA4), Zeta­chain­associated protein kinase 70 (ZAP70) and LCK proto­oncogene (LCK) were significantly increased, whereas HGF expression levels were decreased in RA synovial tissue. In conclusion, these findings suggest that the identified DEGs and pivotal genes in the present study may further enhance our knowledge of the underlying pathways in the pathogenesis of RA. These genes may also serve as diagnostic biomarkers and therapeutic targets for RA; however, further experimental validation is necessary following the bioinformatic analysis to determine our conclusions.