TARM1 is a receptor protein whose role in the functioning of the immune system is unknown. In a new study, scientists from Japan, led by Professor Yoichiro Iwakura from Tokyo University of Science, and Rikio Yabe and Shinobu Saijo from Chiba University, have explored the potential role of TARM1 in the pathogenesis of rheumatoid arthritis by analyzing mouse models.
In their study published in Nature Communications , they found that TARM1 activated dendritic cells, and the development of collagen-induced arthritis (CIA) was notably suppressed in TARM1-deficient mice and by treatment with TARM1-inhibitory soluble TARM1 proteins. This makes the protein a potential therapeutic target.
As Prof. Iwakura explains, “Tarm1 expression is elevated in the joints of rheumatoid arthritis mouse models, and the development of collagen-induced arthritis (CIA) is suppressed in TARM1-deficient mice.”
The scientists observed that the immune system’s response to type 2 collagen (IIC), a protein crucial for the development of CIA in mice, was suppressed in TARM1-deficient mice. They also found that the antigen-presenting ability of DCs in TARM1-deficient mice was impaired.
With respect to the significance of these findings, Prof. Iwakura explains, “We have shown that TARM1 plays an important role in the maturation and activation of DCs through interaction with IIC”. Finally, they injected TARM1-inhibitory soluble TARM1 proteins into the knee of a mouse with CIA. Notably, this suppressed the progression of CIA in the mouse, suggesting that TARM1 inhibition is effective in weakening autoimmune arthritis.
The team’s findings of the TARM1 protein have wide implications with respect to the treatment of rheumatoid arthritis as well as other autoimmune and allergic diseases.
Commenting on their important discoveries, Prof. Iwakura states, “Because excess DC activation is suggested in many autoimmune and allergic diseases, our observations suggest that TARM1 is a good target for the development of new drugs to treat such diseases.”
The findings of this exciting new study surely indicate that there still remains much to be understood about autoimmune diseases like rheumatoid arthritis—and that the more we understand them, the better we can fight them!