Colonic crypts are natural gatekeepers of microbial metabolites to protect stem cells
Gut microbiota is co-evolving with their mammalian hosts for over 15 million years in a mutual symbiotic relationship. While the cellular and molecular mechanisms are currently unknown, they rise to the occasion in adapting to each other’s requirements in a fascinating way. For example, during the third trimester of pregnancy, gut microbiota undergoes a complete makeover to produce more fats by increasing Proteobacteria and Actinobacteria to support the growing baby and pregnant mother (1). The critical nature of gut microbiota is now highly appreciated in development and maintenance of immune, neural, vascular as well as in metabolic systems of the host. Microbiota is considered as a special evolving organ within humans. Several genetic and external factors such as mutations, inflammation, infections, diet, antibiotics are known to affect the dynamics of microbial communities in the intestine and play a critical role in modulating both innate and adaptive immune systems. Several efforts have been made and others are currently underway to define complex microbiota-host interactions (good vs. bad; cause vs. consequence) using animal models. More importantly, it is becoming clear that excessive usage of antibiotics at every stage of human life might have tremendously contributed to the increased metabolic disorders in human populations.