The vimentin intermediate filament network restrains regulatory T cell suppression of graft-versus-host disease

Cameron S McDonald-Hyman, James T. Muller, Michael Loschi, Govindarajan Thangavelu, Asim Saha, Sudha Kumari, Dawn K Reichenbach, Michelle J. Smith, Guoan Zhang, Brent Koehn, Jiqiang Lin, Jason S Mitchell, Brian T Fife, Angela Panoskaltsis-Mortari, Colby J Feser, Andrew Kemal Kirchmeier, Mark J Osborn, Keli L Hippen, Ameeta Kelekar, Jonathan S. SerodyLaurence A. Turka, David H. Munn, Hongbo Chi, Thomas A. Neubert, Michael L. Dustin, Bruce R Blazar

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Regulatory T cells (Tregs) are critical for maintaining immune homeostasis. However, current Treg immunotherapies do not optimally treat inflammatory diseases in patients. Understanding the cellular processes that control Treg function may allow for the augmentation of therapeutic efficacy. In contrast to activated conventional T cells, in which protein kinase C-θ (PKC-θ) localizes to the contact point between T cells and antigen-presenting cells, in human and mouse Tregs, PKC-θ localizes to the opposite end of the cell in the distal pole complex (DPC). Here, using a phosphoproteomic screen, we identified the intermediate filament vimentin as a PKC-θ phospho target and show that vimentin forms a DPC superstructure on which PKC-θ accumulates. Treatment of mouse Tregs with either a clinically relevant PKC-θ inhibitor or vimentin siRNA disrupted vimentin and enhanced Treg metabolic and suppressive activity. Moreover, vimentin-disrupted mouse Tregs were significantly better than controls at suppressing alloreactive T cell priming in graft-versus-host disease (GVHD) and GVHD lethality, using a complete MHC-mismatch mouse model of acute GVHD (C57BL/6 donor into BALB/c host). Interestingly, vimentin disruption augmented the suppressor function of PKC-θ-deficient mouse Tregs. This suggests that enhanced Treg activity after PKC-θ inhibition is secondary to effects on vimentin, not just PKC-θ kinase activity inhibition. Our data demonstrate that vimentin is a key metabolic and functional controller of Treg activity and provide proof of principle that disruption of vimentin is a feasible, translationally relevant method to enhance Treg potency.

Original languageEnglish (US)
Pages (from-to)4604-4621
Number of pages18
JournalJournal of Clinical Investigation
Volume128
Issue number10
DOIs
StatePublished - Oct 1 2018

Bibliographical note

Publisher Copyright:
© 2018 American Society for Clinical Investigation. All rights reserved.

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