Advances in the study of ferroptosis and its relationship to autoimmune diseases.

Ferroptosis represents a novel mode of programmed cell death characterized by the intracellular accumulation of iron and lipid peroxidation, culminating in oxidative stress and subsequent cell demise. Mounting evidence demonstrates that ferroptosis contributes significantly to the onset and progression of diverse pathological conditions and diseases, including infections, neurodegenerative disorders, tissue ischemia-reperfusion injury, and immune dysregulation. Recent investigations have underscored the pivotal role of ferroptosis in the pathogenesis of rheumatoid arthritis, ulcerative colitis, systemic lupus erythematosus, and asthma. This review provides a comprehensive overview of the current understanding of the regulatory mechanisms governing ferroptosis, particularly its interplay with iron, lipid, and amino acid metabolism. Furthermore, we explore the implications of ferroptosis in autoimmune diseases and deliberate on its potential as a promising therapeutic target for diverse autoimmune disorders.

Inhibitory effects of Eplerenone on angiogenesis via modulating SGK1/TGF-ß pathway in contralateral kidney of CKD pregnancy rats.

BACKGROUND: Eplerenone is a selective aldosterone receptor blocker that is effective in preventing the progression of chroinic kidney disease (CKD). However, its mechanism and role in CKD pregnancy still remain uncertain. The aim of this study was to evaluate whether eplerenone could attenuated the fibrosis of unilateral ureteral obstruction (UUO) pregnant rats' contralateral kidney, improved pregnancy outcome and explore its therapeutic mechanisms. METHODS: A pregnancy rat model of UUO established, female Wistar rats were randomly assigned into sham-operated group (Sham group),sham-operated combined pregnancy group (SP group), unilateral ureteral obstruction combined pregnancy group (UUO + Pregnancy group), unilateral ureteral obstruction combined pregnancy, administered eplerenone (UUO + Pregnancy+Eplerenone group). On the 18th day of pregnancy, the rats were placed in a metabolic cage, 24 h urine was collected and stored at -80 °C. Next day, all animals were euthanized, and serum was collected by centrifugation and stored at -20 °C. Then the right kidney was extracted, a part of the kidney was placed in 4% paraformaldehyde for morphology, immunohistochemical staining, and immunofluorescence staining, and the other part was placed in a - 80 °C refrigerator for RNA and protein extraction. In vitro, HUVECs was treated with aldosterone, progesterone and estradiol, VEGFA and its receptor blocker bevacizumab. The ability of proliferation, migration and tubularization of HUVECs was detected by CCK-8, scratch wound assay and endothelial tube formation assay. And the co-expression of CD34 and α-SMA of HUVECs was detected by Flow cytometry. RESULTS: Immunofluorescence results showed that the co-expression of CD34 and α-SMA increased in the UUO + Pregnancy group was significantly increased. The expression of SGK-1, TGFß-1, Smad2, Smad3, VEGF-A, VEGFR2, CD34, α-SMA and Collagen I was significantly higher in the kidneys of the UUO + Pregnancy group compared to the Sham group and SP group. Eplerenone inhibited the expression of those results. In vitro, the ability of proliferation, migration and tubularization was increased after treated with aldosterone, aldosterone with progesterone and estradiol or VEGFA. Similarly, the expression of α-SMA on the surface of HUVECs treated with aldosterone, aldosterone with progesterone and estradiol were increased, while eplerenone supressed its expression. CONCLUSION: Eplerenone inhibits renal angiogenesis by blocking the SGK-1/TGFß signal transduction pathway, thereby inhibiting the phenotypic transformation of endothelial cells, slowing down renal fibrosis, and reducing kidney damage caused by pregnancy.

RNA Seq and ceRNA Network Analysis of the Rat Model of Chronic Kidney Disease.

BACKGROUND: Long non-coding RNAs (lncRNAs) containing microRNA (miRNA) response elements (MREs) can be used as competitive endogenous RNAs (ceRNAs) to regulate gene expression. OBJECTIVE: The purpose of this study was to investigate the expression profile and role of mRNAs and lncRNAs in unilateral ureteral obstruction (UUO) model rats and to explore any associated competing endogenous (ceRNA) network. METHODS: Using the UUO model, the obstructed kidney was collected on the 15th day after surgery. RNA Seq analysis was performed on renal tissues of four UUO rats and four sham rats. Four mRNAs and four lncRNAs of differentially expressed genes were randomly selected for real-time quantitative PCR (RT qPCR) analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were analyzed, and bioinformatics was used to predict MREs. By screening for ceRNAs combined with target gene prediction, a related ceRNA network was constructed and verified by RT-qPCR. RESULTS: We identified 649 up-regulated lncRNAs, 518 down-regulated lncRNAs, 924 downregulated mRNAs and 2029 up-regulated mRNAs. We identified 30 pathways with the highest enrichment in GO and KEGG. According to the RNA Seq results and the expression of Nr4a1, the network was constructed based on Nr4a1 and included two MREs and ten lncRNAs. Furthermore, lncNONRATT011668.2/miR-361-3p/Nr4a1 was identified and verified according to ceRNA sequencing and target gene prediction. CONCLUSION: mRNAs and lncRNAs are differentially expressed in UUO model rats, which may be related to the pathogenesis of chronic kidney disease. The lncNONRATT011668.2/miR-361- 3p/Nr4a1 ceRNA network may be involved in the pathogenesis of chronic kidney disease.

Yiqi Huoxue Tongluo recipe regulates NR4A1 to improve renal mitochondrial function in unilateral ureteral obstruction (UUO) rats.

CONTEXT: Yiqi Huoxue Tongluo recipe (YHTR) is a traditional Chinese medicine for the treatment of chronic kidney disease, but its exact mechanism is not clear. OBJECTIVES: To monitor the potential improvement of renal mitochondrial function in unilateral ureteral obstruction (UUO) rats by regulating NR4A1 using the YHTR. MATERIALS AND METHODS: Wistar rats were randomly divided into four groups: sham, UUO (left ureteral ligation for 14 days), eplerenone (EPL) (UUO + EPL), and YHTR (UUO + YHTR). UUO rats were established and intragastrically administered EPL (100 mg/day/kg) or YHTR (11.7 g/day/kg) for 14 days. The expression of related proteins in kidneys was detected by immunohistochemistry, western blot, RT-PCR, and chemical colorimetric assay, respectively. RESULTS: In vivo, YHTR treatment reduced the levels of BUN and Scr (by 17.9% and 23.5%) in UUO rats. Moreover, YHTR improved the renal mitochondrial function via increasing key enzymes of the tricarboxylic acid (TCA) cycle (p < 0.05) and activity of the mitochondrial complex (I-V) (by 30.8%, 29.1%, 19.7%, 35.9%, and 22.4%) in UUO rats. Compared with the UUO group, the expression of NR4A1 and Bcl-2 were significantly increased (p < 0.05), the expression of caspase-3 and caspase-9 were significantly decreased (p < 0.05) in the YHTR group. YHTR could upregulate key enzymes of the TCA cycle via promoting NR4A1 expression in HK2 cells, leading to inhibition of TGF-ß1 induced cell apoptosis. CONCLUSIONS: YHTR significantly improved the development of CKD; this study may provide new ideas for the pathogenesis of CKD and new strategies for the development of new drugs against CKD.

Paeoniflorin-6'-o-benzene sulfonate ameliorates the progression of adjuvant-induced arthritis by inhibiting the interaction between Ahr and GRK2 of fibroblast-like synoviocytes.

Aryl hydrocarbon receptor (Ahr) is thought to be a crucial factor that regulates immune responses, which may be involved in the pathogenesis of autoimmune inflammation including rheumatoid arthritis (RA). The results of our group in recent years have shown that Paeoniflorin-6'-O-benzene sulfonate (code: CP-25), a novel ester derivative of paeoniflorin, has a good effect on improving RA animal models. However, whether the anti-arthritis effect of CP-25 is related to Ahr remains unclear. Here, we showed that CP-25 treatment ameliorated adjuvant-induced arthritis (AA), a rat model of RA, by inhibiting Ahr-related activities in fibroblasts like synoviocytes (FLS). AA rats were treated with CP-25 or paroxetine from days 17 to 33 after immunization. We showed that CP-25 alleviated arthritis symptoms and the pathological changes. Treatment with CP-25 decreased the expression of Ahr in the synovium of AA rats. CP-25 inhibited the expression of Ahr and the G protein-coupled receptor kinase 2 (GRK2) as well as the co-expression of GRK2 with Ahr in FLS of AA rats. Furthermore, CP-25 down-regulated the production of Kyn in FLS of AA rats. These results suggested that CP-25 may inhibit the expression and activation of Ahr. Besides, treatment with CP-25 reduced the proliferation and migration of MH7A caused by Ahr activation. In addition, we also demonstrated that CP-25 down-regulated the total and nuclear expression of Ahr and the expression of GRK2 in Kyn-treated MH7A. Moreover, the co-expression and co-localization of Ahr and GRK2in Kyn-treated MH7A were also repressed by CP-25. The data presented here demonstrated that CP-25 suppressed FLS dysfunction in rats with AA, which were associated with reduced Ahr activation and the interaction between Ahr and GRK2.