Encephalopathy due to the Sugihiratake mushroom - Shizuoka University and Utsunomiya University clarify that onset caused by three substances

The Sugihiratake mushroom of the Tricholomataceae family (Pleurocybella porrigens), has primarily been eaten in Japan's Hokuriku, Chubu, and Tohoku regions. However, since September 2004, cases of suspected acute encephalopathy (a brain disturbance that leads to problems such as confusion and memory loss) due to ingestion of these mushrooms occurred in Niigata, Yamagata, and Akita prefectures.

At the time, it was widely reported as the worst case of food poisoning since World War II. The Ministry of Health, Labour and Welfare set up a research group to investigate the cause, but ultimately concluded that the cause was "unknown," and the group was dissolved in 2006.

A research group of Honorary Distinguished Professor Hirokazu Kawagishi of Shizuoka University (also a member of the original research group at the time), Associate Professor Tomohiro Suzuki of Utsunomiya University, Associate Professor Tomohiro Asakawa of Tokai University, and Chief Senior Researcher Fumihiko Maekawa of the National Institute for Environmental Studies continued, even after the research group was dissolved, to work on understanding the mechanism by which acute encephalopathy was caused by the mushroom, and succeeded in purifying a novel protein (named pleurocybelline) from sugihiratake that exhibits lethal activity against mice. The research group found that pleurocybelline and a lectin (PPL) derived from the sugihiratake mushroom form a complex and exhibit proteolytic activity. Furthermore, they previously predicted that this mixture of pleurocybelline, PPL, and pleurocybellaziridine (PA), a structurally determined compound that has been shown to be toxic to neurons and cause damage in the brains of mice in the past, was present in the sugihiratake mushroom and proved its existence through chemical synthesis.

Based on these results, the research group proposed a new toxicity mechanism in which three substances in the sugihiratake mushroom are involved in the onset of acute encephalopathy. The results were published in the online edition of Toxicon.

Journal Information
Publication: Toxicon
Title: Possible molecular mechanism for acute encephalopathy by angel-wing mushroom ingestion - Involvement of three constituents in onset -
DOI: 10.1016/j.toxicon.2022.106958