Identification of a novel receptor which recognizes mushroom beta-1,6-glucan

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K06166
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40020:Wood science-related
• Research Institution: Utsunomiya University
• Principal Investigator: Konno Naotake 宇都宮大学, 農学部, 准教授 (60549880)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: β-グルカン / きのこ / 糖質関連酵素 / 免疫賦活

Outline of Final Research Achievements

β-1,6-Glucan, a cell wall component of fungi, is known as a bioactive (immunostimulation) polysaccharide. In this study, the cDNAs encoding β-1,6-glucan degrading enzymes (β-1,6-glucanases) were cloned from basidiomycetes, and the β-1,6-glucanase from Coprinopsis cinerea (Cc30) was heterologously expressed in Aspergillus oryzae. Cc30 catalyzed depolymerization of β-1,6-glucan endolytically, and was highly specific toward β-1,6-glucan polysaccharide. Lichen Umbilicaria species produce linear glucan composed of only β-1,6-linkages. We prepared β-1,6-glucan oligosaccharides from the hot-water extracts of Umbilicaria esculenta using the obtained β-1,6-glucanase. Antitumor activities of β-1,6-glucan oligosaccharides were analyzed by expression of inflammatory cytokine genes (TNF-α and IL-6) in mouse macrophage-like cell line RAW264.7 cells. High-purity β-1,6-glucan oligosaccharides of over pentasaccharides were suggested to have immunostimulatory properties.

Free Research Field

生物高分子材料学

Academic Significance and Societal Importance of the Research Achievements

β-1,6-グルカンの生理機能に関する知見は、きのこ類に新しい価値を見出すことにつながる。きのこ類は木質バイオマスを基材として生産できる唯一の食品で、健康補助食品や医薬品としての可能性も持つ。食用きのこの大量栽培が可能になってきた一方で、近年は消費量は伸び悩んでいる。きのこ類には生体内において生理機能を示す多糖類が存在することから、これらの機能性を活用すれば、きのこ市場の拡大と、理想的な木材のカスケード利用システムの構築が期待できる。