"Psoriasis" is a chronic dermatitis that tends to develop in places that are susceptible to irritation or with aging, and is said to affect 1000 to 2 out of 5 people in Japan.The most widely used drug for the treatment of dermatitis is a topical steroid, but it is known to have side effects such as dry skin and easy pimples, so it is a new topical drug, especially for long-term psoriasis. Development is expected.

　The research group previously discovered that TRAF6, a substance in the epidermal cells that cover the surface of the skin, is an essential substance for the onset and persistence of psoriasis.Therefore, we investigated the intracellular substance activated by TRAF6, and focused on the enzyme p38-MAP kinase. Since p38-MAP kinase is activated in psoriasis lesions and is easily activated by external stimuli and aging, it was considered that activation of p38-MAP kinase may be a factor in the onset of psoriasis.

　The research group conducted an experiment to apply a p38-MAP kinase activator to the skin of mice and found that they developed symptoms similar to psoriasis.On the other hand, it was found that psoriasis did not occur when a p38-MAP kinase inhibitor was also applied here.Furthermore, we found that the action of p38-MAP kinase inhibitors on the skin of lesions taken from patients with psoriasis suppressed the production of inflammatory substances in the skin tissue.

　From the above, it was suggested that activation of p38-MAP kinase is a sufficient condition for the onset of psoriasis, and therefore, the development of an external drug that suppresses p38-MAP kinase leads to the treatment of dermatitis including psoriasis.From this result, the research group intends to explore the possibility of developing a new external drug to replace steroids.

Paper information:[Journal of Allergy and Clinical Immunology] Cutaneous p38 mitogen-activated protein kinase activation triggers psoriatic dermatitis