共生真菌重现肠道细菌的防护益处

Title：
Commensal Fungi Recapitulate the Protective Benefits of Intestinal Bacteria

DOI：
10.1016/j.chom.2017.10.013

Abstract：
Highlights •Commensal fungi functionally replace intestinal bacteria in mitigating tissue injury •Commensal fungi positively calibrate the activation of protective CD8 T cells •Protective benefits of commensal fungi require persistent intestinal colonization •Fungal cell-wall mannans recapitulate the protective benefits of commensal fungi Summary Commensal intestinal microbes are collectively beneficial in preventing local tissue injury and augmenting systemic antimicrobial immunity. However, given the near-exclusive focus on bacterial species in establishing these protective benefits, the contributions of other types of commensal microbes remain poorly defined. Here, we show that commensal fungi can functionally replace intestinal bacteria by conferring protection against injury to mucosal tissues and positively calibrating the responsiveness of circulating immune cells. Susceptibility to colitis and influenza A virus infection occurring upon commensal bacteria eradication is efficiently overturned by mono-colonization with either Candida albicans or Saccharomyces cerevisiae. The protective benefits of commensal fungi are mediated by mannans, a highly conserved component of fungal cell walls, since intestinal stimulation with this moiety alone overrides disease susceptibility in mice depleted of commensal bacteria. Thus, commensal enteric fungi safeguard local and systemic immunity by providing tonic microbial stimulation that can functionally replace intestinal bacteria.

All Authors：
Tony T Jiang , Tzu-Yu Shao , WX Gladys Ang , Jeremy M Kinder , Lucien H Turner , Giang Pham , Jordan Whitt , Theresa Alenghat , Sing Sing Way

First Authors：
Tony T Jiang

Correspondence：
Sing Sing Way

内容要点：

以往的研究明确了肠道有益细菌对黏膜屏障的保护作用，但很少有研究把关注点放到有益真菌上。用抗生素处理后的小鼠，肠屏障受损，对结肠炎和甲型流感病毒敏感，而在肠道单一定殖假丝酵母菌或酿酒酵母，就可有效逆转这样的状况。 保护作用由真菌细胞壁上非常保守的组成——甘露聚糖介导，在肠道中，它自身就可以逆转清除共生细菌后小鼠的疾病敏感性。 若要发挥保护作用，真菌需要长期在肠道定殖，并正向刺激保护性CD8+T细胞激活。