Recent findings in Akkermansia muciniphila-regulated metabolism and its role in intestinal diseases

The mammalian gastrointestinal tract is colonized with a majority of gut microbes, affecting host metabolism and homeostasis. Gut microbiota plays a vital role in nutrient exchange, signaling transduction between intestinal epithelial cells, and resistance to pathogen invasion. Gut microbiota is divided into mucus layer bacteria and intestinal lumen bacteria based on the colonization distribution. Akkermansia muciniphila (A. muciniphila) prefers to colonize in the intestinal mucus layer, and specifically degrades mucins to produce short-chain fatty acids, providing energy for the host and promoting colonization of the bacterium itself. Degradation of mucins prompts the host to compensate for the production of more mucins, thereby maintaining the dynamics of these proteins. In the intestinal micro-ecosystem, A. muciniphila is non-pathogenic, and its colonization with suitable abundance contributes to the development of immune system, thus promoting intestinal health. The mechanisms by which A. muciniphila bears a protective role in the host intestine are currently unclear. In this review, we summarize the microenvironment for the colonization of A. muciniphila, physiological characteristics and pathophysiological impact of A. muciniphila on intestinal diseases, such as irritable bowel syndrome, inflammatory bowel diseases, and intestinal tumors. We also provided updates for current studies on signals that A. muciniphila enhances intestinal barrier integrity and regulates immune response. Together, we conclude that A. muciniphila is a promising probiotic, which could be a microbial target for the treatment of multiple intestinal diseases.