Foxp3 drives oxidative phosphorylation and protection from lipotoxicity
Duncan Howie, … , Alexander G. Betz, Herman Waldmann
Duncan Howie, … , Alexander G. Betz, Herman Waldmann
Published February 9, 2017
Citation Information: JCI Insight. 2017;2(3):e89160. https://doi.org/10.1172/jci.insight.89160.
View: Text | PDF
Research Article Immunology Metabolism

Foxp3 drives oxidative phosphorylation and protection from lipotoxicity

Abstract

Tregs can adopt a catabolic metabolic program with increased capacity for fatty acid oxidation–fueled oxidative phosphorylation (OXPHOS). It is unclear why this form of metabolism is favored in Tregs and, more specifically, whether this program represents an adaptation to the environment and developmental cues or is “hardwired” by Foxp3. Here we show, using metabolic analysis and an unbiased mass spectroscopy–based proteomics approach, that Foxp3 is both necessary and sufficient to program Treg-increased respiratory capacity and Tregs’ increased ability to utilize fatty acids to fuel oxidative phosphorylation. Foxp3 drives upregulation of components of all the electron transport complexes, increasing their activity and ATP generation by oxidative phosphorylation. Increased fatty acid β-oxidation also results in selective protection of Foxp3+ cells from fatty acid–induced cell death. This observation may provide novel targets for modulating Treg function or selection therapeutically.

Authors

Duncan Howie, Stephen Paul Cobbold, Elizabeth Adams, Annemieke Ten Bokum, Andra Stefania Necula, Wei Zhang, Honglei Huang, David J. Roberts, Benjamin Thomas, Svenja S. Hester, David J. Vaux, Alexander G. Betz, Herman Waldmann

×

Figure 6

Foxp3-driven fatty acid β-oxidation protects Tregs from long-chain fatty acid–mediated apoptosis.

Options: View larger image (or click on image) Download as PowerPoint
Foxp3-driven fatty acid β-oxidation protects Tregs from long-chain fatty...
(A) C57BL/6 CD4+ T cells were cultured for 18 hours in the presence of IL-2 (5 U/ml) and IL-7 (10 ng/ml), in addition to the indicated BSA-conjugated long-chain fatty acid at a concentration of 500 μM. Apoptosis was measured by mitochondrial cytochrome c release (Cyt.C), mitochondrial loss of mitochondrial membrane potential (Δψm, JC1 stain), and 7AAD/annexin V staining according to Methods. Results representative of 2–5 separate experiments. (B) C57BL/6.Foxp3hCD2/CD52 knockin CD4+ T cells were cultured for 18 hours with IL-2, IL-7, and the indicated BSA-conjugated long-chain fatty acid before flow cytometric analysis of surface human CD2 (Foxp3) and 7AAD/annexin V positivity. Results representative of 4 pooled experiments. Boxes span 25th to 75th percentiles, whiskers represent minimum and maximum values, and horizontal line shows median. *P < 0.05 by Student’s t test. (C) Titration of BSA-conjugated palmitate. Cells cultured as in B with titrated amounts of BSA-conjugated palmitate prior to flow analysis of surface human CD2 and 7AAD/annexin V positivity. Results pooled from 3 biological repeats. Means ± SEM. *P < 0.05 by Student’s t test. (D) Uptake of BODIPY-labeled palmitate by CD4+ T cells from C57BL/6.Foxp3hCD2/CD52 knockin mice. Results representative of 3 separate experiments. (E) Schematic of fatty acid β-oxidation pathway showing major enzymes and their inhibitors used in this study. Inset: ratiometric data (Foxp3+/Foxp3–) from mass spectrometry analysis of the major β-oxidation enzymes, where present, in MARKI iTreg and EL4cFoxp3 T cells. (F) C57BL/6.Foxp3hCD2/CD52 knockin CD4+ T cells were cultured for 18 hours with IL-2, IL-7, and BSA-conjugated palmitate with the addition of the indicated inhibitors before flow cytometric analysis of surface human CD2 (Foxp3) and 7AAD/annexin V positivity. Results pooled from 3 separate biological repeats. Boxes span 25th to 75th percentiles, whiskers represent minimum and maximum values, and horizontal line shows median, *P < 0.05 by Student’s t test.