Rheumatoid arthritis

The protective effect of gentisic acid on rheumatoid arthritis via the RAF/ERK signaling pathway

Background

RAF and ERK pathways are known to be activated in human rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS), which play an important role in the pathogenesis and destruction of RA. Gentisic acid (GA) was a natural product derived from plants, which has been reported can attenuate pressure overload‐induced cardiac hypertrophy and fibrosis in mice through inhibition of the ERK1/2 pathway. Whether GA can inhibit the occurrence and development of RA through RAF/ERK signaling pathway has not been reported. The purpose of this study is to determine whether GA may have a certain therapeutic effect on RA-FLS.

Method

Bovine type II collagen was used to establish a rat model of rheumatism. Enzyme-linked immunosorbent assay was used to detect inflammatory factors, anti-inflammatory mediators, and rheumatoid factor. Hematoxylin and eosin and TUNEL staining were used to detect the effect of GA on histochemical with rheumatoid arthritis. RAF, ERK, and p-ERK expressions in synovial tissue were measured by western blot and immunohistochemical. Besides, human rheumatoid arthritis fibroblast-like synoviocytes cell line MH7A was used to investigate the biological behavior influenced by GA. Apoptosis assay was performed to detect apoptosis of GA on MH7A cells. Transwell invasion assay was performed to detect the ability of cell migration.

Result

The result showed that GA could reduce joint swelling and inflammation. At the same time, it can also promote the apoptosis of synovial cells and down-regulate the RAF/ERK pathway.

Conclusion

GA may ameliorate inflammatory factors’ abnormality, synovial hyperplasia, and apoptosis of synovium via inhibiting the RAF/ERK signaling pathway.

Rheumatoid arthritis in identical twins: a clinical and immunogenetic study of eight concordant pairs derived from a nationwide twin panel

The nationwide Finnish Twin Cohort was linked with the national Sickness Insurance Register. Eight identical twin pairs concordant for rheumatoid arthritis (RA) fulfilling the American Rheumatism Association criteria were identified. All 16 cases were known to be seropositive. Four pairs had at least one additional first-degree relative with RA, and the prevalence of RA among all the first-class relatives was 9%. HLA-typing was performed for 15 patients representing the eight pairs; six pairs carried the DR4 allele, and three of these pairs were putative homozygotes. Nodules and Sjögren syndrome occurred fairly frequently (in 7 of 16 and 6 of 13 cases examined, respectively), but concordance within pairs was no higher than that expected by chance. The course of the disease was fulminant in one patient and in several others the disease had led to marked joint destructions. The findings pointed out to some intrapair similarity in the progression of the joint damage and in the type of complications caused by gold.

HLA-DR4 subtype frequencies in rheumatoid arthritis indicate that DRB1 is the major susceptibility locus within the HLA class II region

Susceptibility to rheumatoid arthritis (RA) may be due to the presence of shared functional epitopes common to the HLA-DR beta chains of several RA-associated haplotypes. We have obtained direct evidence for this hypothesis by using the polymerase chain reaction and sequencing the DRB1 and DQB1 genes from RA patients. A highly conserved epitope present on DR beta chains of DR4 and DR1 haplotypes was found in 83% of 149 patients with classical or definite RA but was found in only 46% of 100 control individuals (P less than 0.0001). Two Dw subtypes of DR4 (Dw4 and Dw14) were associated with disease susceptibility but two other subtypes (Dw10 and Dw13) were not. Sequence differences between these subtypes implicate those residues around the putative antigen binding site of the DR beta molecule in the pathogenesis of RA. These data provide a basis for understanding host susceptibility to RA at a molecular level.