肠道菌群多糖利用及代谢

Glycan utilization and metabolism by gut microbiota

摘要:

宿主与肠道共生菌之间存在一种互利共生的关系。肠道共生菌可以代谢宿主自身不能消化的多糖。进入肠道内的多糖是影响肠道共生菌生理状态和组成的重要因素，这些多糖主要来自饮食和宿主的粘膜分泌物。人类饮食中含有几十种不同的膳食多糖，其中大多数不能被人类基因组中编码的酶降解，并进入大肠，供肠道共生菌利用。肠道共生菌将这些不易消化的多糖转化为短链脂肪酸，作为大肠细胞和其他肠道上皮细胞的营养物质。除此之外，短链脂肪酸对人体健康有着重要的影响。不同的肠道共生菌对进入肠道内的多糖具有不同的偏好性，表明摄入膳食多糖是一种可以直接影响肠道内共生菌物种平衡的策略。因此，研究肠道菌群的多糖代谢机制具有重要的意义。本文从肠道共生菌的组成、利用进入肠道内多糖的机制，以及产生的代谢产物可能对人体健康存在的潜在影响等方面进行了综述，并介绍了代表性的肠道共生菌如拟杆菌和双歧杆菌利用多糖的途径及特征。

Abstract:

The gut microbiota is a changing ecosystem, containing trillions of bacteria, continuously shaped by many factors, such as dietary habits, seasonality, lifestyle, stress, antibiotics use, or diseases. Diet is the key determinant of the microbiota configuration, through modulation of the abundance of specific species and their individual or collective functions. Most complex plant polysaccharides from diet are not digested by humans and enter the colon as a potential nutrient source for the microbiota. Gut microbiota can convert these undigestible polysaccharides into short-chain fatty acids (SCFAs). Besides, SCFAs are likely to have broad impacts on various aspects of host physiology. Dietary fibers interact directly with gut microbes and lead to the production of key metabolites such as short-chain fatty acids. Dietary fibers can be considered key ancestral compounds that preserve gut ecology, especially regulating macronutrients and host physiology. Here we summarize the composition of intestinal symbiotic bacteria, the utilization of polysaccharides entering the intestinal tract, and the potential impact of metabolites on human health.