Chonkit Lio

Background: Rheumatoid arthritis (RA) involves persistent synovial inflammation together with progressive cartilage damage and bone erosion. Fibroblast-like synoviocytes (FLS) and macrophages are abundant in the inflamed synovium, but how their interactions contribute to matrix-destructive responses is less well defined. Methods: We integrated public bulk and single-cell transcriptomic analyses with experimental validation in collagen-induced arthritis (CIA) tissues to investigate inflammatory, redox-associated, and matrix-remodeling alterations in the RA synovial microenvironment. Bioinformatic analyses, intercellular communication modeling, histological assessment, enzyme-linked immunosorbent assay (ELISA), and immunoblotting were subsequently performed to characterize stromal–immune interactions and Nuclear factor erythroid 2-related factor 2 (NRF2)-associated signaling changes. Results: Single-cell analysis identified synovial immune-cell populations and predicted interactions between fibroblast-like synoviocytes (FLS) and macrophages. CellChat analysis identified extracellular matrix- and inflammatory-associated pathways, including POSTN–integrin and macrophage migration inhibitory factor (MIF)-related signaling, in FLS-to-macrophage communication. Bulk transcriptomic analyses showed higher expression of matrix metallopeptidase 3 (MMP3) and matrix metallopeptidase 13 (MMP13) in RA synovial tissue. RA synovial tissues exhibited elevated expression of matrix metallopeptidase 3 (MMP3) and matrix metallopeptidase 13 (MMP13), while RA macrophages showed increased oxidative stress-associated transcriptional signatures. In CIA rats, increased expression of NRF2-associated antioxidant proteins was accompanied by parallel reduced synovial inflammation and decreased MMP3 and MMP13 expression. Conclusions: These findings suggest that stromal–immune interactions in RA may involve altered macrophage redox regulation associated with matrix-degrading responses. NRF2-associated pathways may therefore contribute to the coordination of inflammatory and tissue-destructive processes in RA.

Ferroptosis is an iron-dependent form of regulated cell death characterized by the lethal accumulation of lipid peroxides and has emerged as an important contributor to the initiation, progression, and amplification of inflammatory responses. DNA methylation, histone modifications, and noncoding RNA-mediated regulation influence ferroptosis by modulating multiple molecular pathways, thereby shaping the inflammatory microenvironment. Active constituents and compound formulas of traditional Chinese medicine (TCM) exhibit multi-target, multi-pathway regulatory properties that enable the simultaneous regulation of epigenetic modifications, ferroptosis, and inflammation. However, the molecular mechanisms linking these processes have not been systematically summarized. This review discusses the molecular mechanisms underlying ferroptosis, the epigenetic mechanisms that regulate ferroptosis, and the reciprocal interplay between ferroptosis and inflammation. It further highlights recent advances in understanding how active constituents and compound formulas of TCM modulate ferroptosis through epigenetic regulation to alleviate inflammatory injury. By integrating current evidence, this review provides mechanistic insights into the epigenetic basis of the anti-inflammatory actions of TCM and underscores the therapeutic potential of epigenetic modulation of ferroptosis for the treatment of inflammatory diseases.

Rheumatoid arthritis (RA) is a systemic immune-related disease characterized by chronic synovial inflammation and progressive joint destruction. However, the molecular mechanisms and diagnostic biomarkers underlying RA remain unclear. In this study, we aimed to identify potential biomarkers for clinical diagnosis of RA and to investigate their association with immune infiltration. By integrating differentially expressed genes analysis (DEGs) and weighted gene co-expression network analysis (WGCNA), we identified PSMB9 as a hub gene associated with RA. Gene set enrichment analysis (GSEA) and immune infiltration analysis revealed a strong association between RA and macrophage infiltration. Single-cell RNA sequencing datasets also suggest that PSMB9 is not only highly expressed in macrophage but is also present in synovial cells. We employed cellular thermal shift assay (CETSA) combined with Western blot to validate the interaction between sinomenine (SIN) and the target protein. CETSA results demonstrated that, compared with the control group, SIN increased the thermal stability of PSMB9, suggesting direct binding between the two. Western blot experiments further confirmed that PSMB9 protein expression was significantly downregulated following SIN treatment. PSMB9 may serve as potential diagnostic biomarker and therapeutic targets for RA. Moreover, our data suggest SIN may exert anti-inflammatory effects through regulation of PSMB9. This study also provides an additional insight into the underlying mechanisms involved in the progression of RA and discover a new molecular target for SIN.

DNA methylation is a crucial epigenetic mechanism that modifies the epigenome without altering the DNA sequence, leading to heritable changes in gene expression and playing a vital role in biological processes. The regulation of DNA methylation has gained significant attention in recent years for its role in inflammatory diseases, with numerous studies indicating a correlation between abnormal gene methylation and disease development. However, current research on mature methylation-regulation drugs remains in its infancy. Traditional Chinese medicine (TCM) has been demonstrated to have a potential therapeutic effect in treating inflammatory diseases by modulating DNA methylation. In this review, we provide an overview of how DNA methylation participates in inflammatory diseases and how TCM assesses its function in regulating DNA methylation modifications. We aim to demonstrate a theoretical foundation for further research on the therapeutic targets and mechanisms of TCM in inflammatory disease treatment.

Akebia saponin D (ASD) is derived from the Dipsacus asper Wall. ex Henry, which is a traditional Chinese medicine commonly used to treat rheumatic arthritis (RA). However, the in-depth mechanism of the anti-inflammatory effect of ASD is still unclear. This study aimed to preliminarily explore the anti-inflammatory effect of ASD and the underlying mechanisms from the perspective of DNA methylation and inflammation-related pathways. We found that ASD significantly reduced the production of multiple inflammatory mediators, including nitric oxide (NO) and prostaglandin E₂ (PGE₂), in LPS-induced RAW264.7 cells. The expression of DNA methyltransferase (DNMT) 3b and inducible nitric oxide synthase (iNOS) was also obviously inhibited by the ASD treatment. The protein and mRNA levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were also significantly inhibited by ASD. ASD inhibited the macrophage M1 phenotype, inhibited the high level of DNMT3b, and downregulated the signal transducer and activator of the transcription 3 (STAT3) pathway to exert its anti-inflammatory activity. Furthermore, DNMT3b siRNA and Nrf2 siRNA significantly promoted the anti-inflammatory effect of ASD. Our study demonstrates for the first time that ASD inhibits the IL-6-STAT3-DNMT3b axis and activates the nuclear factor-E2-related factor 2 (Nrf2) signaling pathway to achieve its inhibitory effect on inflammatory reactions.

Nardochinoid B (NAB) is a new compound isolated from Nardostachys chinensis. Although our previous study reported that the NAB suppressed the production of nitric oxide (NO) in lipopolysaccharide (LPS)-activated RAW264.7 cells, the specific mechanisms of anti-inflammatory action of NAB remains unknown. Thus, we examined the effects of NAB against LPS-induced inflammation. In this study, we found that NAB suppressed the LPS-induced inflammatory responses by restraining the expression of inducible nitric oxide synthase (iNOS) proteins and mRNA instead of cyclooxygenase-2 (COX-2) protein and mRNA in RAW264.7 cells, implying that NAB may have lower side effects compared with nonsteroidal anti-inflammatory drugs (NSAIDs). Besides, NAB upregulated the protein and mRNA expressions of heme oxygenase (HO)-1 when it exerted its anti-inflammatory effects. Also, NAB restrained the production of NO by increasing HO-1 expression in LPS-stimulated RAW264.7 cells. Thus, it is considered that the anti-inflammatory effect of NAB is associated with an induction of antioxidant protein HO-1, and thus NAB may be a potential HO-1 inducer for treating inflammatory diseases. Moreover, our study found that the inhibitory effect of NAB on NO is similar to that of the positive drug dexamethasone, suggesting that NAB has great potential for developing new drugs in treating inflammatory diseases.