Autoimmune diseases are caused by abnormal immune cells recognizing and attacking host healthy cells and tissues, including inflammation such as Rheumatoid arthritis and crohn’s disease. Inflammatory cytokines are involved in developing autoimmune diseases through hyperimmune response and proliferation of autoreactive cells.
Interleukin-6 (IL-6) is an inflammatory cytokine that signals cells by interacting with IL-6 receptor (IL-6R). Unregulated IL-6 signals immune cells such as dendritic cells and T cells and promotes proliferation of them. Proliferated cells promote autoimmune diseases development due to secretion of additional inflammatory cytokines followed by hyperimmunity.
IL-6/IL-6R interaction inhibitor achieves treatment of autoimmune diseases by binding IL-6 or IL-6R and inhibiting their signaling. Although existing IL-6/IL-6R inhibitors such as antibody drugs have been developed, they are expensive and difficult to be administered orally due to their large size. Therefore, to overcome these disadvantages, developing smaller and less expensive IL-6/IL-6R interaction inhibitor is important for treatments of autoimmune diseases.
Here, we report discovery of novel cyclic peptides for development of small-size and low-cost IL-6/IL-6R interaction inhibitor.