In the past decades, use of antibiotics has received widely debate all over the world as its adverse side effects. However, safety profiles of newer drugs are often not as well-established as for those that have a long history of use. Prof. YIN Yulong’s group in the Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA) has spent several decades in functional amino acids investigations in order to find an active substance to replace, at least partly, the use of antibiotics. Among 23 kinds of amino acids, arginine is a precursor for synthesis of many biologically active molecules with low molecular weights, including nitric oxide (NO), ornithine, polyamines, creatine, and agmatine. Plus, dietary supplementation with arginine has been demonstrated to exhibit physiologic and immunologic functions, including nutritional metabolism, oxidative stress, tissue growth and development, and immune response.

More recently, Dr. REN Wenkai from Prof. YIN Yulong’s group and collaborated with Prof. Wu form Texas A&M University systemically investigated the regulatory functions of arginine on intestinal microbiota and innate immunity in mice, which has provided a novel therapeutic avenue in intestinal microecological disturbance and natural immune diseases.

The researchers found that dietary arginine supplementation changes the intestinal microbiota, contributing to the activation of Toll-like receptors signaling. This, in turn, induces expression proinflammatory cytokines, production of intestinal sIgA, and activation of goblet cells and Paneth cells through NF-KB, MAPK, and PI3K-phosphorylated-Akt signaling pathways. Meanwhile, the effects of arginine on intestinal microbiota and innate immunity have been shown to be dependent on the segment of the gut with different populations of bacteria. Basing current literature, this is the first report on the impact of arginine on intestinal microbiota and innate immunity in aminals and aids in enhancing understanding of basic knowledge about the nutrition, physiology, and immunology of arginine.

The research was supported by National Natural Science Foundation of China (31330075, 31001016, 31201813, and 31101729), Animal Intestinal Microflora Research Network Laboratory of the Chinese Academy of Sciences, the Chinese Academy of Sciences/State Administration of Foreign Experts Affairs International Partnership Program for Creative Research Teams, and Texas A&M AgriLife Research project 8200.

The study entitled “Dietary Arginine Supplementation of Mice Alters the Microbial Population and Activates Intestinal Innate Immunity” has been published in the “The journal of Nutrition”, more details could be found at http://jn.nutrition.org/content/144/6/988.