Ablation of peroxiredoxin II attenuates experimental colitis by increasing FoxO1-induced Foxp3+ regulatory T cells.
Peroxiredoxin (Prx) II is an intracellular antioxidant molecule that eliminates hydrogen peroxide, employing a high substrate-binding affinity. PrxII deficiency increases the levels of intracellular reactive oxygen species in many types of cells, which may increase reactive oxygen species-mediated inflammation. In this study, we investigated the susceptibility of PrxII knockout (KO) mice to experimentally induced colitis and the effects of PrxII on the immune system. Wild-type mice displayed pronounced weight loss, high mortality, and colon shortening after dextran sulfate sodium administration, whereas colonic inflammation was significantly attenuated in PrxII KO mice. Although macrophages were hyperactivated in PrxII KO mice, the amount of IFN-γ and IL-17 produced by CD4(+) T cells was substantially reduced. Foxp3(+) regulatory T (Treg) cells were elevated, and Foxp3 protein expression was increased in the absence of PrxII in vitro and in vivo. Restoration of PrxII into KO cells suppressed the increased Foxp3 expression. Interestingly, endogenous PrxII was inactivated through hyperoxidation during Treg cell development. Furthermore, PrxII deficiency stabilized FoxO1 expression by reducing mouse double minute 2 homolog expression and subsequently activated FoxO1-mediated Foxp3 gene transcription. PrxII overexpression, in contrast, reduced FoxO1 and Foxp3 expression. More interestingly, adoptive transfer of naive CD4(+) T cells from PrxII KO mice into immune-deficient mice attenuated T cell-induced colitis, with a reduction in mouse double minute 2 homolog expression and an increase in FoxO1 and Foxp3 expression. These results suggest that inactivation of PrxII is important for the stability of FoxO1 protein, which subsequently mediates Foxp3(+) Treg cell development, thereby attenuating colonic inflammation.
College of Pharmacy and Global Top 5 Research Program, Ewha Womans University, Seoul 120-750, Korea.
Hee Yeon
HY
Won
Eun Jung
EJ
Jang
Kihyun
K
Lee
Sera
S
Oh
Hyo Kyung
HK
Kim
Hyun Ae
HA
Woo
Sang Won
SW
Kang
Dae-Yeul
DY
Yu
Sue-Goo
SG
Rhee
Eun Sook
ES
Hwang
D019264:Adoptive Transfer; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D003092:Colitis / Q000235:genetics / Q000276:immunology*; D016264:Dextran Sulfate; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D007371:Interferon-gamma / Q000378:metabolism; D020381:Interleukin-17 / Q000378:metabolism; D008262:Macrophage Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D054464:Peroxiredoxins / Q000235:genetics / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000096:biosynthesis / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism
D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; C467200:Foxo1 protein, mouse; C498833:Foxp3 protein, mouse; D020381:Interleukin-17; D017382:Reactive Oxygen Species; D007371:Interferon-gamma; D016264:Dextran Sulfate; D054464:Peroxiredoxins; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2