Involvement of RORγt-overexpressing T cells in the development of autoimmune arthritis in mice.
BACKGROUND
Differentiation of T helper 17 cells is dependent on the expression of transcription retinoid-related orphan receptor gamma t (RORγt). The purpose of our study is to determine the role of RORγt expression in T cells on the development of collagen-induced arthritis (CIA).


METHODS
CIA was induced in C57BL/6 and T cell-specific RORγt transgenic (RORγt Tg) mice. At day 10 post-1st-immunization, lymph node (LN) cells were cultured with type II collagen (CII), and the expression levels of various cytokines and transcription factors on CD4+ T cells were measured. Total cells or CD4+ cells of draining LN were harvested from each mouse group after CII-immunization and transferred into C57BL/6 mice, and then CIA was induced in recipient mice. The expression levels of RORγt and other surface antigens, and the production of cytokines were analyzed in forkhead box P3 (Foxp3)+ regulatory T (Treg) cells. Foxp3+ Treg cells were analyzed for suppressive activity against proliferation of effector CD4+ T cells. Interlukin (IL)-10 neutralizing antibody was administrated in the course of CIA.


RESULTS
CIA was significantly suppressed in RORγt Tg mice compared with C57BL/6 mice. RORγt expression and IL-17 production were significantly higher in CII-reactive CD4+ T cells from RORγt Tg mice. Arthritis was significantly attenuated in C57BL/6 mice recipient of cells from RORγt Tg mice. Most of Foxp3+ Treg cells expressed RORγt, produced IL-10 but not IL-17, and overexpressed CC chemokine receptor 6 (CCR6) and surface antigens related to the suppressive activity of Foxp3+ Treg cells in RORγt Tg mice. In vitro suppression assay demonstrated significant augmentation of the suppressive capacity of Foxp3+ Treg cells in RORγt Tg mice. CIA was exacerbated in both C57BL/6 mice and RORγt Tg mice by the treatment of anti-IL-10 antibody.


CONCLUSIONS
Our results indicated that RORγt overexpression in T cells protected against the development of CIA. The protective effects were mediated, at least in part, through the anti-inflammatory effects including high production of IL-10 of RORγt+Foxp3+ Treg cells.
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. YuKond@md.tsukuba.ac.jp.
Yuya
Y
Kondo
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. yao.yao.076@gmail.com.
Zhaojin
Z
Yao
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. s1230430@u.tsukuba.ac.jp.
Masahiro
M
Tahara
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. mana-iizuka09@ob.md.tsukuba.ac.jp.
Mana
M
Iizuka
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. niigata4530@yahoo.co.jp.
Masahiro
M
Yokosawa
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. my.shunta22@gmail.com.
Shunta
S
Kaneko
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. ssegawa@md.tsukuba.ac.jp.
Seiji
S
Segawa
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. Hiroto-Tsuboi@md.tsukuba.ac.jp.
Hiroto
H
Tsuboi
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. k-yoh@md.tsukuba.ac.jp.
Keigyou
K
Yoh
Department of Anatomy and Embryology, Faculty of Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. satoruta@md.tsukuba.ac.jp.|International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. satoruta@md.tsukuba.ac.jp.|Life Science Center, Tsukuba Advanced Research Alliance (TARA), University of Tsukuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. satoruta@md.tsukuba.ac.jp.|Laboratory Animal Resource Center (LARC), University of Tsukuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. satoruta@md.tsukuba.ac.jp.
Satoru
S
Takahashi
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. ismatsu@md.tsukuba.ac.jp.
Isao
I
Matsumoto
Department of Internal Medicine, Faculty of Medicine, University of Tuskuba, 1-1-1 Tennodai, Tsukuba City, Ibaraki, 305-8575, Japan. tsumida@md.tsukuba.ac.jp.
Takayuki
T
Sumida
D000818:Animals; D001169:Arthritis, Experimental / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D001327:Autoimmune Diseases / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D005434:Flow Cytometry; D005786:Gene Expression Regulation; D051379:Mice; D008810:Mice, Inbred C57BL; D057132:Nuclear Receptor Subfamily 1, Group F, Member 3 / Q000096:biosynthesis / Q000235:genetics*; D012313:RNA / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
D057132:Nuclear Receptor Subfamily 1, Group F, Member 3; D012313:RNA