May 27, 2022
Keio University School of Medicine
A research group from the Keio University School of Medicine, led by Project Assistant Professor Yosuke Harada and Professor Takanori Kanai of the Division of Gastroenterology and Hepatology, and Senior Lecturer Tomohisa Sujino of the Endoscopy Center, has discovered that immune cells located directly beneath the small intestinal epithelium are induced and maintained by adapting to the hypoxic environment created by gut microbiota.
In the digestive tract of mammals, including humans, a sophisticated balance is maintained, absorbing necessary nutrients without overreacting to food and bacteria from the external environment, while also identifying and eliminating dangerous substances. In the small intestine, a layer of small intestinal epithelial cells forms a boundary with the pathway for substances sent from the stomach, and it is known that various immune cells exist, sandwiched in the gaps between these cells. In particular, CD4 + CD8αα + cells, which are abundant among the small intestinal epithelium, are known to suppress enteritis caused by pathogenic bacteria. However, the factors by which these cells are generated and maintained were not well understood.
In this study, the research group discovered that CD4 + CD8αα + cells, which have low oxygen demand, can exist in the small intestinal epithelial region by adapting to the hypoxic environment created by gut microbiota and by expressing and regulating characteristic genes suited to this environment.
Amid growing understanding in recent years that disturbances in the gut environment are closely related to the onset of various diseases, this study has found that immune cells possess a mechanism to skillfully adapt to hypoxic conditions, contributing to the maintenance of homeostasis. The advancement of this research is expected to lead to the development of new therapies focusing on genes expressed under oxygenation and hypoxia.
The results of this research were published in the international academic journal "iScience" on April 15, 2022 (US time).
For the full press release, please see below.