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Loss of Nrf2 in bone marrow-derived macrophages impairs antigen-driven CD8+ T cell function by limiting GSH and Cys availability

Authors :
Annika Klara Giegerich
Lisa K. Sha
Ralf P. Brandes
Tilo Knape
Weixiao Sha
Laura Kuchler
Andreas von Knethen
Bernhard Brüne
Ryan G. Snodgrass
Andreas Weigert
Katrin Schröder
Andreas Daiber
Publica
Source :
Free Radical Biology and Medicine. 83:77-88
Publication Year :
2015
Publisher :
Elsevier BV, 2015.

Abstract

NF-E2-related factor 2 (Nrf2), known to protect against reactive oxygen species, has recently been reported to resolve acute inflammatory responses in activated macrophages. Consequently, disruption of Nrf2 promotes a proinflammatory macrophage phenotype. In the current study, we addressed the impact of this macrophage phenotype on CD8(+) T cell activation by using an antigen-driven coculture model consisting of Nrf2(-/-) and Nrf2(+/+) bone marrow-derived macrophages (BMDMΦ) and transgenic OT-1 CD8(+) T cells. OT-1 CD8(+) T cells encode a T cell receptor that specifically recognizes MHC class I-presented ovalbumin OVA(257-264) peptide, thereby causing a downstream T cell activation. Interestingly, coculture of OVA(257-264)-pulsed Nrf2(-/-) BMDMΦ with transgenic OT-1 CD8(+) T cells attenuated CD8(+) T cell activation, proliferation, and cytotoxic function. Since the provision of low-molecular-weight thiols such as glutathione (GSH) or cysteine (Cys) by macrophages limits antigen-driven CD8(+) T cell activation, we quantified the amounts of intracellular and extracellular GSH and Cys in both cocultures. Indeed, GSH levels were strongly decreased in Nrf2(-/-) cocultures compared to wild-type counterparts. Supplementation of thiols in Nrf2(-/-) cocultures via addition of glutathione ester, N-acetylcysteine, β-mercaptoethanol, or cysteine itself restored T cell proliferation as well as cytotoxicity by increasing intracellular GSH. Mechanistically, we identified two potential Nrf2-regulated genes involved in thiol synthesis in BMDMΦ: the cystine transporter subunit xCT and the modulatory subunit of the GSH-synthesizing enzyme γ-GCS (GCLM). Pharmacological inhibition of γ-GCS-dependent GSH synthesis as well as knockdown of the cystine antiporter xCT in Nrf2(+/+) BMDMΦ mimicked the effect of Nrf2(-/-) BMDMΦ on CD8(+) T cell function. Our findings demonstrate that reduced levels of GCLM as well as xCT in Nrf2(-/-) BMDMΦ limit GSH availability, thereby inhibiting antigen-induced CD8(+) T cell function.

Details

ISSN :
08915849
Volume :
83
Database :
OpenAIRE
Journal :
Free Radical Biology and Medicine
Accession number :
edsair.doi.dedup.....8bbac17fcfe3f096824a15b22e4c4035
Full Text :
https://doi.org/10.1016/j.freeradbiomed.2015.02.004