Regenerating islet-derived protein (Reg)3β plays a crucial role in attenuation of ileitis and colitis in mice

Ryodai Shindo; Takaharu Katagiri; Sachiko Komazawa-Sakon; Masaki Ohmuraya; Wakami Takeda; Yoshiko Nakagawa; Naomi Nakagata; Tetsushi Sakuma; Takashi Yamamoto; Chiharu Nishiyama; Takashi Nishina; Soh Yamazaki; Hideto Kameda; Hiroyasu Nakano

doi:10.1016/j.bbrep.2020.100738

Regenerating islet-derived protein (Reg)3β plays a crucial role in attenuation of ileitis and colitis in mice

Biochem Biophys Rep. 2020 Feb 7:21:100738. doi: 10.1016/j.bbrep.2020.100738. eCollection 2020 Mar.

Authors

Affiliations

¹ Department of Biochemistry, Toho University Graduate School Medicine, 5-21-16 Omori-Nishi, Ota-ku, Tokyo, 143-8540, Japan.
² Division of Rheumatology, Department of Internal Medicine, Ohashi Medical Center, 2-22-36 Ohashi, Meguro-ku, Tokyo, 153-8515, Japan.
³ Department of Genetics, Hyogo College of Medicine, Nishinomiya, Hyogo, 663-8501, Japan.
⁴ Laboratory of Molecular Biology and Immunology, Department of Biological Science and Technology, Faculty of Industrial Science and Technology, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo, 125-8585, Japan.
⁵ Center for Animal Resources and Development, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto, 860-0811, Japan.
⁶ Division of Integrated Sciences for Life, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan.
⁷ Host Defense Research Center, Toho University School of Medicine, 5-21-16 Omori-Nishi, Ota-ku, Tokyo, 143-8540, Japan.

Abstract

Regenerating islet-derived protein (Reg)3β belongs to a member of the Reg family of proteins and has pleiotropic functions, including antimicrobial activity and tissue repair. However, whether Reg3β plays a protective role in the development of colitis and ileitis has not been fully investigated. We generated transgenic mice expressing a short form of cellular FLICE-inhibitory protein (cFLIPs) that promotes necroptosis, a regulated form of cell death. cFLIPs transgenic (CFLARs Tg) mice develop severe ileitis in utero. Although Reg3β is undetectable in the small intestine of wild-type embryos, its expression is aberrantly elevated in the small intestine of CFLARs Tg embryos. To test whether elevated Reg3β attenuates or exacerbates ileitis in CFLARs Tg mice, we generated a Reg3b ^-/- strain. Reg3b ^-/- mice grew to adulthood without apparent abnormalities. Deletion of Reg3b in CFLARs Tg mice exacerbated the embryonic lethality of CFLARs Tg mice. Dextran sulfate sodium-induced colitis, characterized by body weight loss and infiltration of neutrophils, was exacerbated in Reg3b ^-/- compared to wild-type mice. Moreover, the expression of Interleukin 6, an inflammatory cytokine and Chitinase-like 3, a marker for tissue repair macrophages was elevated in the colon of Reg3b ^-/- mice compared to wild-type mice after DSS treatment. Together, these results suggest that attenuation of colitis and ileitis is a result of Reg3β's real function.

Keywords: Arg1, Arginase-1; CFLARs Tg, cFLIPs transgenic; Cellular FLICE-Inhibitory protein; Chitinase-like 3, Chil3; Colitis; DSS, dextran sulfate sodium; Dextran sulfate sodium; GFP, green fluorescent protein; IECs, intestinal epithelial cells; IL, interleukin; ILC3, group 3 innate lymphoid cell; Ileitis; MLKL, mixed lineage kinase domain–like protein; Mrc1, Mannose receptor C-type 1; RIPK, receptor-interacting protein kinase; RORγt, RAR-related orphan receptor gamma t; Reg, regenerating islet-derived protein; Regenerating islet-derived protein; Retnla, Resistin-like alpha; STAT, signal transducer and activator of transcription; cFLIPs and L, cellular FLICE-inhibitory protein, short and long forms; pSTAT3, phospho-STAT3; qPCR, quantitative polymerase chain reaction.