2022/03/09
Faculty of Pharmacy, Keio University
A research group at Keio University has discovered a new mechanism by which the gut microbiota contributes to the host's defense against oxidative stress. This research is the work of a research group from the Faculty of Pharmacy at Keio University, led by Jun Uchiyama of the Department of Pharmacy, Project Lecturer Masahiro Akiyama of the same faculty, and Professor Yungi Kim.
Oxidative stress is known to be involved in the onset of many diseases. Therefore, maintaining the quantity of antioxidants in the body is crucial for maintaining health. In recent years, it has become clear that various metabolites produced by gut bacteria cross the intestinal tract and affect the functions of various host organs. However, the contribution of gut bacteria to the host's antioxidant capacity has remained unclear.
In this study, we discovered that the gut microbiota contributes to maintaining and increasing the in vivo levels of reactive sulfur species, which are antioxidants. We also found that gut bacteria enzymatically produce cysteine persulfide (CysSSH), a type of reactive sulfur species, using cystine as a substrate. Consequently, when cystine was administered to mice, plasma concentrations of reactive sulfur increased in a gut microbiota-dependent manner, and oxidative stress-induced liver damage was suppressed. Furthermore, we were also able to identify gut bacteria that are high producers of reactive sulfur species.
Oxidative stress increases due to factors such as poor diet and lifestyle habits, psychological and physical stress, and aging. As a result, oxidative damage to DNA and proteins by reactive oxygen species occurs, leading to cardiovascular diseases, cancer, diabetes, and neurodegenerative diseases. The results of this study suggest that gut bacteria that are high producers of reactive sulfur species may play a protective role against our oxidative stress. In the future, it is hoped that this will lead to advances in drug discovery and food development using these high-producing bacteria of reactive sulfur species or substances that enhance their function.
These findings are expected to lead to the elucidation of a new molecular basis for the interaction between the host and gut bacteria. The results of this research were published in the online edition of the international academic journal "Cell Reports" on March 8, 2022 (US Eastern Standard Time).
Please see below for the full press release.