Bioinformatics-based study to identify immune infiltration and inflammatory-related hub genes as biomarkers for the treatment of rheumatoid arthritis.

Rheumatoid arthritis (RA) is a systemic autoimmune disease whose principal pathological change is aggressive chronic synovial inflammation; however, the specific etiology and pathogenesis have not been fully elucidated. We downloaded the synovial tissue gene expression profiles of four human knees from the Gene Expression Omnibus database, analyzed the differentially expressed genes in the normal and RA groups, and assessed their enrichment in functions and pathways using bioinformatics methods and the STRING online database to establish protein-protein interaction networks. Cytoscape software was used to obtain 10 hub genes; receiver operating characteristic (ROC) curves were calculated for each hub gene and differential expression analysis of the two groups of hub genes. The CIBERSORT algorithm was used to impute immune infiltration. We identified the signaling pathways that play important roles in RA and 10 hub genes: Ccr1, Ccr2, Ccr5, Ccr7, Cxcl5, Cxcl6, Cxcl13, Ccl13, Adcy2, and Pnoc. The diagnostic value of these 10 hub genes for RA was confirmed using ROC curves and expression analysis. Adcy2, Cxcl13, and Ccr5 are strongly associated with RA development. The study also revealed that the differential infiltration profile of different inflammatory immune cells in the synovial tissue of RA is an extremely critical factor in RA progression. This study may contribute to the understanding of signaling pathways and biological processes associated with RA and the role of inflammatory immune infiltration in the pathogenesis of RA. In addition, this study shows that Adcy2, Cxcl13, and Ccr5 have the potential to be biomarkers for RA treatment.

Evodiamine attenuates adjuvant-induced arthritis in rats by inhibiting synovial inflammation and restoring the Th17/Treg balance.

OBJECTIVES: Evodiamine (Evo) possesses strong anti-inflammatory activity. In this study, we determine the antiarthritic effect of Evo. METHODS: Evo was administered to rats with adjuvant-induced arthritis (AA). We evaluated arthritis symptoms & histopathological changes and measured inflammatory cell infiltration, pro-inflammatory cytokine production and Th17 & Treg percentages in arthritic rats. KEY FINDINGS: Evo significantly improved the clinical signs of AA in rats, including decreases in paw swelling, the polyarthritis index and the number of swollen paw joints. Based on the histopathological analysis, Evo improved synovial inflammation and bone injury by inhibiting inflammatory cell infiltration, synoviocyte proliferation, pannus formation and cartilage erosion. Furthermore, the numbers of synovial CD3+ or CD68+ inflammatory cells were reduced, and the elevated levels of tumour necrosis factor-α, interleukin-1ß (IL-1ß) and IL-6 were restored to control levels by the Evo treatment. In addition, Evo therapy regulated the abnormal differentiation of Treg and Th17 cells, decreasing IL-17 production and increasing IL-10 levels. Finally, Evo inhibited Stat3 phosphorylation and induced Stat5 phosphorylation in rats with AA. CONCLUSIONS: Based on our results, Evo is a promising antiarthritic agent, potentially due to its inhibitory effect on synovial inflammation and regulatory effects on Treg and Th17 differentiation.

Epidermal growth factor increases the expression of Nestin in rat reactive astrocytes through the Ras-Raf-ERK pathway.

Astrocytes undergo de-differentiation and become activated during a response to injury. Several studies have found that reactive astrocytes re-express markers, such as Nestin, which are normally expressed in neural stem cells. It was recently shown that the epidermal growth factor receptor (EGFR) is up-regulated in astrocytes after injury and promotes reactive astrocyte transformation. However, the signaling pathways involved in this process have not been elucidated. In the present study, we showed that Nestin was strongly expressed in reactive astrocytes. Furthermore, as shown by immunoblot analyses, epidermal growth factor (EGF) regulated Nestin expression through EGFR activation. Inhibition of the PLCγ, PI3K, ERK, p38, and JNK pathways did not affect Nestin expression in reactive astrocytes. However, treatment with a Raf-1 inhibitor inhibited Nestin expression in a concentration-dependent manner. Taken together, the signaling analyses revealed that EGF induced and regulated Nestin expression through activation of the Ras-Raf--ERK signaling pathway. This is the first study to show that Nestin expression is regulated by an extracellular signaling molecule in reactive astrocytes.

Chordin-like protein 1 promotes neuronal differentiation by inhibiting bone morphogenetic protein-4 in neural stem cells.

In the present study, the effects of chordin­like protein 1 (CHRDL1) overexpression, together with bone morphogenetic protein­4 (BMP­4) treatment, on the differentiation of rat spinal cord­derived neural stem cells (NSCs) was investigated. Adult rat spinal cord­derived NSCs were cultured in serum­free medium. The recombined eukaryotic expression vector pSecTag2/Hygro B­CHRDL1 was transfected into adult rat spinal cord­derived NSCs using a lipid­based transfection reagent and protein expression was assessed by western blot analysis. Differentiation of transfected NSCs following BMP­4 treatment was determined by immunocytochemistry. The percentage of microtubule­associated protein­2 (MAP­2)­positive cells in the BMP­4­treated (B) group was found to be significantly lower compared with that in the non­transfected control (N) group. The percentage of MAP­2­positive cells in the pSecTag2/Hygro B­CHRDL1­transfected, BMP­4­treated group was identified to be significantly higher compared with that in group B, however, no significant difference was observed between group N and the transfected, non­BMP­4­treated control group. The current study indicates that CHRDL1 protein antagonizes BMP­4 activity and induces spinal cord­derived NSCs to differentiate into neurons.