Polysaccharides from Paecilomyces hepiali Prevent Acute Colitis in Association with Modulating Gut Microbiota and Treg/Th17 Immune Balance in Mice

Cordyceps exopolysaccharide (CEP) has shown emerging potential in adjustment of gut microbiota and immune cell function. In this study, a water-soluble CEP with a molecular weight of 58.14 kDa was extracted from the fermentation broth of Paecilomyces hepiali, an endophytic fungus of Cordyceps sinensis. Our results indicated that Paecilomyces hepiali polysaccharide (PHP) showed significantly preventive potential on dextran sulfate sodium (DSS)-induced colitis in mice, which can prevent colon shortening, reduce intestinal epithelial cell (IEC) destruction, suppress inflammatory cell infiltration, and regulate the balance between regulatory T (Treg) cells and T helper type 17 (Th17) cells. Meanwhile, the disturbed gut microbiota was partially restored after PHP treatment. Further Pearson correlation coefficient analyses exhibited that the alteration of the gut microbiota was significantly related to adjustment of the IEC barrier and Treg/Th17 balance. In conclusion, all findings proposed that purified PHP has the potential to develop into a promising agent for colitis prevention and adjuvant therapy via maintaining intestinal homeostasis of gut microbiota and immune system.

[Discussion on related problems of model species of fungus： Paecilomyces hepialid]

Paecilomyces hepiali is a new species of fungus isolated from a field collection of Ophiocordyceps sinensis from Baima snow mountain, Diqing Tibetan Autonomous Prefecture, Yunnan Province by the Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences. The specimen was identified and named as Paecilomyces hepiali by Qing-Tao Chen, the professor of the Institute of Microbiology, Chinese Academy of Sciences (Paecilomyces hepiali) (2008), who identified a dried culture of living strain 82-2 as the holotype. Until now, the holotype (the voucher specimen) was deposited in the Herbarium of the Institute of Chinese Materia Medica (HICMM), China Academy of Chinese Medical Sciences, Beijing. The P. hepiali neotype designated by the paper "Neotypification of P. hepiali (Hypocreales)" published in TAXON 64 (1) by Yao Yi-Jian et al. in February 2015 is untenable.