Rheumatoid arthritis: safe and sound

miR-145 eliminates lipopolysaccharides-induced inflammatory injury in human fibroblast-like synoviocyte MH7A cells

Recently, it has been accepted that miR-based therapy may be beneficial for rheumatoid arthritis (RA). This study aimed to evaluate the potential involvement of miR-145 in RA in vitro. The expression of miR-145 in the human fibroblast-like synoviocyte line MH7A was overexpressed by miR-mimic transfection, after which cells were subjected to lipopolysaccharides (LPS). Cell viability, apoptosis, and the release of pro-inflammatory cytokines were measured. The result showed that the apoptosis and the release of IL-1β, IL-6, IL-8, and TNF-α were significantly induced by LPS. Meanwhile, LPS treatment led to downregulation of miR-145. miR-145 overexpression in LPS-untreated MH7A cells had no impacts on cell apoptosis and inflammation. But, restoring miR-145 expression in LPS-stimulated cells by supplementation of a miR-145 mimic protected MH7A cells against LPS-induced apoptosis and inflammation. Furthermore, miR-145 overexpression in LPS-untreated MH7A cells slightly blocked the PI3K/ATK and mTOR pathways, whereas miR-145 overexpression in LPS-stimulated cells notably repressed the LPS-induced activation of PI3K/ATK and MAPK/mTOR pathways. Our study suggested that miR-145 protected MH7A cells against LPS-induced apoptosis and inflammation by inhibiting the PI3K/AKT and MAPK/mTOR pathways.

Immunosuppressive exosomes: a new approach for treating arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease and one of the leading causes of disability in the USA. Although certain biological therapies, including protein and antibodies targeting inflammatory factors such as the tumor necrosis factor, are effective in reducing symptoms of RA, these treatments do not reverse disease. Also, although novel gene therapy approaches have shown promise in preclinical and clinical studies to treat RA, it is still unclear whether gene therapy can be readily and safely applied to treat the large number of RA patients. Recently, nanosized, endocytic-derived membrane vesicles “exosomes” were demonstrated to function in cell-to-cell communication and to possess potent immunoregulatory properties. In particular, immunosuppressive DC-derived exosomes and blood plasma- or serum-derived exosomes have shown potent therapeutic effects in animal models of inflammatory and autoimmune disease including RA. This paper discusses the current knowledge on the production, efficacy, mechanism of action, and potential therapeutic use of immunosuppressive exosomes for arthritis therapy.