Evaluation of levels of oxidative stress as a potential biomarker in patients with rheumatoid arthritis

Buyang Huanwu Decoction reduces mitochondrial autophagy in rheumatoid arthritis synovial fibroblasts in hypoxic culture by inhibiting the BNIP3-PI3K/Akt pathway

OBJECTIVES

To investigate the role of the BNIP3-PI3K/Akt signaling pathway in mediating the inhibitory effect of Buyang Huanwu Decoction (BYHWT) on mitochondrial autophagy in human synovial fibroblasts from rheumatoid arthritis patients (FLS-RA) cultured under a hypoxic condition.

METHODS

Forty normal Wistar rats were randomized into two groups (n=20) for daily gavage of BYHWT or distilled water for 7 days to prepare BYHWT-medicated or control sera. FLS-RA were cultured in routine condition or exposed to hypoxia (10% O2) for 24 h wigh subsequent treatment with IL-1β, followed by treatment with diluted BYHWT-medicated serum (5%, 10% and 20%) or control serum. AnnexinV-APC/7-AAD double staining and T-AOC kit were used for detecting apoptosis and total antioxidant capacity of the cells, and the changes in ROS, ATP level, mitochondrial membrane potential and Ca2+ homeostasis were analyzed. The changes in mRNA and protein expressions of BNIP3, PI3K and AKT and mRNA expressions of LC3, Beclin-1 and P62 were detected using RT-qPCR and Western blotting.

RESULTS

Treatment with BYHWT-medicated serum dose-dependently lowered apoptosis rate of IL-1β-induced FLS-RA with hypoxic exposure. The treatment significantly decreased T-AOC concentration, increased ROS production, autophagosome formation and ATPase levels, and lowered mitochondrial membrane potential and Ca2+ level in the cells. In IL-1β-induced FLS-RA with hypoxic exposure, treatment with BYHWT-medicated serum significantly increased BNIP3 protein expression, decreased the protein expressions of PI3K and AKT, increased the mRNA expressions of BNIP3 and P62, and lowered the mRNA expressions of PI3K, AKT, LC3 and Beclin-1 without significantly affecting Beclin-1 protein expression. The cells treated with 5% and 10% BYHWT-medicated serum showed no significant changes in LC3 expression.

CONCLUSIONS

BYHWT inhibits mitochondrial autophagy in IL-1β-induced FLS-RA with hypoxic exposure possibly by inhibiting BNIP3-mediated PI3K/AKT signaling pathway.

Measurement of Oxidative Stress Index (OSI) in Penile Corpora Cavernosa and Peripheral Blood of Peyronie's Disease Patients: A Report of 49 Cases

Peyronie's disease (PD) is a chronic inflammatory disease affecting the penile albuginea. Oxidative stress (OS) is important for the development of the disease; therefore, it seemed interesting to us to directly measure OS at both the site of the disease and in peripheral blood. For a precise OS study, it is necessary to evaluate not only the single results of the total oxidant status (TOS) and total antioxidant status (TAS) but also their ratio: OS index (OSI) (arbitrary unit) = TOS/TAS × 100. This study included 49 PD patients examined and diagnosed in our Peyronie's care center and a control group of 50 cases. We collected blood samples from both the penis and a vein in the upper extremity; we used d-ROMs and PAT-test (FRAS kit) for OS measurement. Pearson's study found a statistical correlation between penile OSI values and PD plaque volumes: p-value = 0.002. No correlation was found between systemic OSI values and PD plaque volumes: p-value = 0.27. Penile OSI values were significantly reduced after the elimination of the PD plaque (p < 0.00001). The mean value of the penile OSI indices in the PD patients after plaque elimination corresponded to 0.090 ± 0.016 (p = 0.004). The comparison between the penile OSI values of the PD patients (with plaque elimination) and the control group revealed no statistically significant differences (p = 0.130). The absence of a correlation between Peyronie's plaque volume and systemic OSI values indicates that it is preferable to carry out the OS study by taking a sample directly from the site of the disease. By carrying out a penile OSI study, it would be possible to obtain a precise plaque-volume-dependent oxidative marker. Even if the study did not demonstrate any correlation between OSI indices and anxious-depressive state, we detected a high prevalence of anxiety (81.6%) and depression (59.1%) in PD patients.

Ferroptosis as an emerging target in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease of unknown etiology. Due to the rise in the incidence rate of RA and the limitations of existing therapies, the search for new treatment strategies for RA has become a global focus. Ferroptosis is a novel programmed cell death characterized by iron-dependent lipid peroxidation, with distinct differences from apoptosis, autophagy, and necrosis. Under the conditions of iron accumulation and the glutathione peroxidase 4 (GPX4) activity loss, the lethal accumulation of lipid peroxide is the direct cause of ferroptosis. Ferroptosis mediates inflammation, oxidative stress, and lipid oxidative damage processes, and also participates in the occurrence and pathological progression of inflammatory joint diseases including RA. This review provides insight into the role and mechanism of ferroptosis in RA and discusses the potential and challenges of ferroptosis as a new therapeutic strategy for RA, with an effort to provide new targets for RA prevention and treatment.

Polymorphisms in microRNA binding site of SET8 regulate the risk of rheumatoid arthritis

Rheumatoid arthritis (RA) is a complex, heterogeneous, progressive and long-term autoimmune disease characterized by symmetrical joint inflammation and bone erosion. The etiology of RA is unclear, but its pathogenesis is associated with oxidative stress and inflammatory cytokines. Single nucleotide polymorphisms (SNPs) in the microRNA (miRNA)-binding sites modify the development of rheumatic disease by regulating the expression of target genes. The present study investigated whether SNPs in the miRNA binding site in the 3' untranslated region (3'-UTR) of SET domain containing (lysine methyltransferase) 8 (SET8) and Keratin 81 (KRT81), namely rs16917496 and rs3660, respectively, were associated with the occurrence of RA. The polymerase chain reaction-ligase detection reaction assay showed that the distribution frequencies of the CC genotype (P=0.025) of SNP rs16917496 in SET8 were significantly higher in patients with RA than in healthy controls, which indicated that the CC genotype was associated with an increased risk of RA. SET8 expression in the blood samples of CC genotype carriers was lower than that of TT genotype carriers. Moreover, the CC genotype carriers exhibited higher reactive oxygen species (ROS) levels (1011.500±536.426 vs. 548.616±190.508, P=0.032) and lower interleukin-10 (IL-10) levels (P<0.001). The present study demonstrated that SNP rs16917496 in the 3'-UTR of SET8 was a predictor of RA risk and may regulate RA development by mediating expression of SET8, thereby regulating the levels of ROS and IL-10.