Slc3a2 Mediates Branched-Chain Amino-Acid-Dependent Maintenance of Regulatory T Cells

Publication date: 14 November 2017
Source:Cell Reports, Volume 21, Issue 7
Author(s): Kayo Ikeda, Makoto Kinoshita, Hisako Kayama, Shushi Nagamori, Pornparn Kongpracha, Eiji Umemoto, Ryu Okumura, Takashi Kurakawa, Mari Murakami, Norihisa Mikami, Yasunori Shintani, Satoko Ueno, Ayatoshi Andou, Morihiro Ito, Hideki Tsumura, Koji Yasutomo, Keiichi Ozono, Seiji Takashima, Shimon Sakaguchi, Yoshikatsu Kanai, Kiyoshi Takeda
Foxp3⁺ regulatory T (Treg) cells, which suppress immune responses, are highly proliferative in vivo. However, it remains unclear how the active replication of Treg cells is maintained in vivo. Here, we show that branched-chain amino acids (BCAAs), including isoleucine, are required for maintenance of the proliferative state of Treg cells via the amino acid transporter Slc3a2-dependent metabolic reprogramming. Mice fed BCAA-reduced diets showed decreased numbers of Foxp3⁺ Treg cells with defective in vivo proliferative capacity. Mice lacking Slc3a2 specifically in Foxp3⁺ Treg cells showed impaired in vivo replication and decreased numbers of Treg cells. Slc3a2-deficient Treg cells showed impaired isoleucine-induced activation of the mTORC1 pathway and an altered metabolic state. Slc3a2 mutant mice did not show an isoleucine-induced increase of Treg cells in vivo and exhibited multi-organ inflammation. Taken together, these findings demonstrate that BCAA controls Treg cell maintenance via Slc3a2-dependent metabolic regulation.

Graphical abstract

Teaser

Treg cells regulate excess immune responses and are highly proliferative in vivo. Ikeda et al. find that branched-chain amino acids (BCAAs) are essentially required to maintain expansion and the suppressive capacity of Treg cells via Slc3a2 and mTORC1.


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