Kyoshiro Tsuge

Prostaglandins (PGs) are the major lipid mediators in animals and which are biosynthesized from arachidonic acid by the cyclooxygenases (COX-1 or COX-2) as the rate-limiting enzymes. Prostaglandin E2 (PGE2), which is the most abundantly detected PG in various tissues, exerts versatile physiological and pathological actions via four receptor subtypes (EP1-4). Non-steroidal anti-inflammatory drugs, such as aspirin and indomethacin, exert potent anti-inflammatory actions by the inhibition of COX activity and the resulting suppression of PG production. Therefore, PGE2 has been shown to exacerbate several inflammatory responses and immune diseases. Recently, studies using mice deficient in each PG receptor subtype have clarified the detailed mechanisms underlying PGE2-associated inflammation and autoimmune diseases involving each EP receptor. Here, we review the recent advances in our understanding of the roles of PGE2 receptors in the progression of acute and chronic inflammation and autoimmune diseases. PGE2 induces acute inflammation through mast cell activation via the EP3 receptor. PGE2 also induces chronic inflammation and various autoimmune diseases through T helper 1 (Th1)-cell differentiation, Th17-cell proliferation and IL-22 production from Th22 cells via the EP2 and EP4 receptors. The possibility of EP receptor-targeted drug development for the treatment of immune diseases is also discussed.

A rare and autosomal recessive premature aging disorder, Werner syndrome (WS) is characterized by the early onset of aging-associated diseases, including shortening stature, alopecia, bilateral cataracts, skin ulcers, diabetes, osteoporosis, arteriosclerosis, and chromosomal instability, as well as cancer predisposition. WRN, the gene responsible for WS, encodes DNA helicase with a 3′ to 5′ exonuclease activity, and numerous studies have revealed that WRN helicase is involved in the maintenance of chromosome stability through actions in DNA, e.g., DNA replication, repair, recombination, and epigenetic regulation via interaction with DNA repair factors, telomere-binding proteins, histone modification enzymes, and other DNA metabolic factors. However, although these efforts have elucidated the cellular functions of the helicase in cell lines, they have not been linked to the treatment of the disease. Life expectancy has improved for WS patients over the past three decades, and it is hoped that a fundamental treatment for the disease will be developed. Disease-specific induced pluripotent stem (iPS) cells have been established, and these are expected to be used in drug discovery and regenerative medicine for WS patients. In this article, we review trends in research to date and present some perspectives on WS research with regard to the application of pluripotent stem cells. Furthermore, the elucidation of disease mechanisms and drug discovery utilizing the vast amount of scientific data accumulated to date will be discussed.