Development of Interleukin-1 Receptor Antagonist Mutants with Enhanced Antagonistic ActivityIn Vitroand Improved Therapeutic Efficacy in Collagen-Induced Arthritis

Altered Expression of MicroRNAs in Rheumatoid Arthritis

Rheumatoid arthritis is one of the most common types of inflammatory joint diseases. Women, smokers, and people with positive family history are more susceptible to this disease. Diagnostic criteria include at least one swollen joint that has not been caused by other diseases. MicroRNAs are non-coding RNAs that are evolutionarily conserved and have a length of 18-25 nucleotides. MicroRNAs control gene expression at the post-transcriptional level via promoting mRNA degradation or translational repression. Recognition of alterations in microRNA status and their respective targets, may offer an opportunity to better identify the pathways that are involved in the etiopathogenesis of autoimmune diseases. It has been suggested that microRNAs may serve as potential biomarkers for both diagnosis and prognosis of autoimmune diseases. Here, we review the available evidence on the deregulations of microRNA expression in rheumatoid arthritis. More precisely, this review focuses on the microRNA involved in T cell regulation and gives perspectives on the use of this microRNA as biomarkers of diagnosis, prognosis, or intervention efficacy. J. Cell. Biochem. 119: 478-487, 2018. © 2017 Wiley Periodicals, Inc.

Glatiramer acetate (GA), the immunomodulatory drug, inhibits inflammatory mediators and collagen degradation in osteoarthritis (OA) cartilage

OBJECTIVE

Glatiramer acetate (GA), the generic name for Copaxone, an immunomodulatory agent, has been shown to induce interleukin-1 receptor antagonist (IL-1Ra) production in macrophages. We therefore tested the effects of GA on the catabolic activities of osteoarthritis (OA) chondrocytes.

DESIGN

Primary human chondrocytes and OA cartilage explants were utilized in this study. IL-1Ra, pro-matrix metalloproteinase-13 (proMMP-13) and prostaglandin E(2) (PGE(2)) were estimated in the cell culture supernatants and in vitro MMP-13 activity was measured using fluorogenic substrate. TaqMan Real-Time quantitative polymerase chain reaction (RT-qPCR) was performed to estimate relative expression levels of genes.

RESULTS

GA treatment significantly increased transcription and production of sIL-1Ra (P=0.001) in both culture models. Furthermore, addition of GA (100 μg) inhibited: (1) spontaneous collagen degradation as assayed by CTX II enzyme-linked immunosorbent assay (ELISA) [mean CTX II (ng/g cartilage)] in control was 7.79 [95% confidence interval (CI) 2.57-13.02]-3.415 (95% CI 0.81-6.02) (P=0.0286); (2) spontaneous proMMP-13 secretion [mean MMP-13 (ng/g cartilage)] in control was 16.98 (95% CI 7.739-26.23)-6.973 (95% CI 1.632-12.31) (P=0.0286); (3) production of IL-1β-induced inflammatory mediators such as nitric oxide (NO) [mean NO (μM)] in IL-1 cultures was 11.47 (95% CI 7.10-15.83)-0.87 (95% CI 0.18-1.56) (P=0.0022); and (4) recombinant MMP-13 in vitro activity (15-25%; P=0.004).

CONCLUSIONS

These data suggest that GA effects may be due to upregulation of IL-1Ra as well as direct inhibition of MMP-13 activity. Based on these studies, we propose that GA has potential for disease modifying properties in OA and should be evaluated in vivo in animal studies.

Cytokine-receptor interactions as drug targets

Cytokines are essential proteins that exert potent control over entire cell populations to fight infections and other pathologies, but can by themselves cause disease. Therefore, cytokine-related drugs act either by stimulating or blocking their activities. Our knowledge of the structures of cytokine-receptor complexes, the biophysical basis of their binding, and their mode of biological activation has substantially increased in recent years. This knowledge has been translated into new drugs and drug candidates. This review summarizes our current understanding of the receptor-mediated activity of cytokines, their relation to health and disease, and the agents in use to activate and block their actions.

Directed evolution of chemotaxis inhibitory protein of Staphylococcus aureus generates biologically functional variants with reduced interaction with human antibodies

Chemotaxis inhibitory protein of Staphylococcus aureus (CHIPS) is a protein that binds and blocks the C5a receptor (C5aR) and formylated peptide receptor, thereby inhibiting the immune cell recruitment associated with inflammation. If CHIPS was less reactive with existing human antibodies, it would be a promising anti-inflammatory drug candidate. Therefore, we applied directed evolution and computational/rational design to the CHIPS gene in order to generate new CHIPS variants displaying lower interaction with human IgG, yet retaining biological function. The optimization was performed in four rounds: one round of random mutagenesis to add diversity into the CHIPS gene and three rounds of DNA recombination by Fragment INduced Diversity (FIND). Every round was screened by phage selection and/or ELISA for decreased interaction with human IgG and retained C5aR binding. The mean binding of human anti-CHIPS IgG decreased with every round of evolution. For further optimization, new amino acid substitutions were introduced by rational design, based on the mutations identified during directed evolution. Finally, seven CHIPS variants with low interaction with human IgG and retained C5aR blocking capacity could be identified.