Effects of sorafenib on fibroblast-like synoviocyte apoptosis in rats with adjuvant arthritis

Advances of the small molecule drugs regulating fibroblast-like synovial proliferation for rheumatoid arthritis

Rheumatoid arthritis (RA) is a type of chronic autoimmune and inflammatory disease. In the pathological process of RA, the alteration of fibroblast-like synoviocyte (FLS) and its related factors is the main influence in the clinic and fundamental research. In RA, FLS exhibits a uniquely aggressive phenotype, leading to synovial hyperplasia, destruction of the cartilage and bone, and a pro-inflammatory environment in the synovial tissue for perpetuation and progression. Evidently, it is a highly promising way to target the pathological function of FLS for new anti-RA drugs. Based on this, we summed up the pathological mechanism of RA-FLS and reviewed the recent progress of small molecule drugs, including the synthetic small molecule compounds and natural products targeting RA-FLS. In the end, there were some views for further action. Compared with MAPK and NF-κB signaling pathways, the JAK/STAT signaling pathway has great potential for research as targets. A small number of synthetic small molecule compounds have entered the clinic to treat RA and are often used in combination with other drugs. Meanwhile, most natural products are currently in the experimental stage, not the clinical trial stage, such as triptolide. There is an urgent need to unremittingly develop new agents for RA.

Huangqin Qingre Qubi Capsule inhibits RA pathology by binding FZD8 and further inhibiting the activity of Wnt/β-catenin signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Huangqin Qingre Qubi Capsule (HQC) is a Chinese herbal compound for the treatment of rheumatoid arthritis (RA), which is made from dry roots of Scutellaria baicalensis Georgi, dry mature seeds of Gardenia jasminoides J.Ellis, dry and mature seeds of Coix lacryma-jobi var. stenocarpa Oliv., dry mature seeds of Amygdalus persica L. and roots and rhizomes of Clematis chinensis Osbeck in the proportion of 10:9:30:5:10. HQC has a significant effect in clinical treatment of RA, which can inhibit RA inflammation, improve oxidative stress state, and effectively relieve symptoms of RA patients.

AIM OF THE STUDY

The anti-arthritis effect of HQC and its mechanism, especially whether it improves RA through FZD8-Wnt/β-catenin signal axis, were studied using adjuvant arthritis (AA) rats and FLS from RA patients.

MATERIALS AND METHODS

Real time qPCR (RT-qPCR), Western blot (WB), confocal microscopy and other molecular biological methods were used to study the anti-RA effect of HQC and its mechanism.

RESULTS

The expression of FZD8 was significantly up-regulated in synovium and FLS of AA rats and RA FLS. FZD8 significantly activated the Wnt/β-catenin signaling pathway, promoted abnormal proliferation of FLS, increased the levels of inflammatory factors IL-1β, IL-6 and IL-8, and significantly increased the expression of matrix metalloproteinase 3 (MMP3) and fibronectin. HQC has significant therapeutic effect on AA rats. Molecular docking and molecular dynamics showed that HQC had a good binding ability with FZD8. We also confirmed that HQC inhibited Wnt/β-catenin signaling pathway by binding FZD8, and reduced the levels of the above inflammatory factors and pathological genes of RA.

CONCLUSIONS

The expression of FZD8 is significantly increased in AA rats and FLS from RA patients. Clarify that HQC improves RA through the FZD8-Wnt/β-catenin signal axis, provide a clear therapeutic mechanism for HQC to improve RA, and also provide a basis for clinical promotion of HQC.

Sorafenib suppresses proliferation rate of fibroblast-like synoviocytes through the arrest of cell cycle in experimental adjuvant arthritis

OBJECTIVES

Rheumatoid arthritis, a recurrent incendiary autoimmune joint syndrome, features by prominent synovial hyperplasia. Fibroblast-like synoviocytes are the executive components in the pathogenesis of rheumatoid arthritis. It is generally accepted that excessive proliferation and reduced apoptosis of fibroblast-like synoviocytes lead to synovial hyperplasia. Our previously studies found that sorafenib could inhibit adjuvant arthritis in rats and induced adjuvant arthritis fibroblast-like synoviocytes apoptosis. Presently, we aim to investigate the inhibitory effect with mechanisms of action of sorafenib on adjuvant arthritis fibroblast-like synoviocytes proliferation.

METHODS

Cell counting kit-8 and flow cytometry detection were conducted to monitor FLSs proliferation and cell cycle. Western blotting and qPCR assays were performed to detect P21, P53, CDK4, CyclinD1 and proliferating cell nuclear antigen content levels.

KEY FINDINGS

Sorafenib significantly inhibited adjuvant arthritis fibroblast-like synoviocytes proliferation with an IC50 value of 4 µmol/L by a concentration-dependent pattern, which accompanies by G1 cell cycle arrest. Also, sorafenib significantly decreased the levels of P21, CyclinD1, CDK4 and proliferating cell nuclear antigen, as well as up-regulated P53 expression in adjuvant arthritis fibroblast-like synoviocytes.

CONCLUSIONS

Sorafenib could inhibit adjuvant arthritis fibroblast-like synoviocytes proliferation via arresting G1/S cell cycle progression, which was partially through CDK4/CyclinD1-mediated pathway, as well as up-regulating P53 and down-regulating proliferating cell nuclear antigen expressions. These results suggest that sorafenib may provide a new paradigm for rheumatoid arthritis treatment.