Cell-intrinsic ceramides determine T cell function during melanoma progression
- Institute of Medical Microbiology, University Hospital Essen, University Duisburg-Essen, Germany
- Institute of Molecular Biology, University Hospital Essen, University Duisburg-Essen, Germany
- Institute of Pharmacy, Freie Universität Berlin, Germany
- Institute of Physiology, University Hospital Essen, University Duisburg-Essen, Germany
- Memorial Sloan Kettering Cancer Center, United States
Figures
Figure 1 with 1 supplement
Ablation of acid sphingomyelinase (Asm) results in decreased T cell activation and enhanced tumor growth.
(A) B16-F1 melanoma cells were transplanted into Smpd1-deficient mice (Asm-KO) mice and control littermates (Asm-WT). Tumor volume was monitored daily once tumors were palpable (n=12–18). (B) Frequencies of CD4+ T cells, CD4+Foxp3+ Tregs, and CD8+ T cells within draining lymph nodes (dLN) and tumor of Asm-KO and Asm-WT mice were determined by flow cytometry. Representative contour plots (dLN) are shown in the left panel. (C) IFN-γ, and CD44 expression of CD4+ and CD8+ tumor-infiltrating lymphocytes (TILs) in tumor-bearing mice. (D) Percentages of Foxp3+ Tregs of CD4+ T cells within spleen of naive Asm-KO and Asm-WT mice were determined by flow cytometry (n=16–17). (E) Sorted CD4+CD25− T cells from Asm-KO and Asm-WT mice were stimulated with anti-CD3 and anti-CD28 in the presence of IL-2 and TGF-β1 (iTreg). Respective controls (Th0) were only stimulated with anti-CD3 and anti-CD28 antibodies. After 3 days, Treg differentiation was analyzed by Foxp3 expression (n=3–4). Results from 2 to 4 independent experiments are depicted as mean ± SEM. Statistical analysis was performed by two-way ANOVA with Sidak’s multiple comparisons or Student’s t-test. (*p<0.05, **p<0.01, ****p<0.0001).
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Figure 1—source data 1
Ablation of Asm results in decreased T cell activation and enhanced tumor growth.
- https://cdn.elifesciences.org/articles/83073/elife-83073-fig1-data1-v1.zip
Figure 1—figure supplement 1
Tumor growth and T cell response in amitriptyline-treated mice.
(A) B16-F1 melanoma cells were injected into amitriptyline-treated mice, and tumor growth was monitored once tumors have been established (n=8–9). (B) CD44 and IFN-γ expression of tumor-infiltrating lymphocytes (TILs) were analyzed by flow cytometry. Results from two independent experiments are depicted as mean ± SEM. Statistical analysis was performed by two-way ANOVA with Sidak’s multiple comparisons or Student’s t-test. (*p<0.05, **p<0.01, ****p<0.0001).
Figure 2
Impaired CD8+ T cell function in acid sphingomyelinase (Asm)-deficient tumor-bearing mice upon CD4+ T cell depletion.
CD4+ T cells were depleted from Asm-WT and Asm-KO mice by repeated i.p. injection of anti-CD4 depleting antibody. Control groups received PBS. B16-F1 tumor cells were transplanted 1 day later subcutaneously. (A) Tumor volume was determined after tumor establishment based on caliper measurements (n=3–7). (B) Frequencies of CD4+ and CD8+ T cells in dLN and tumor and (C) expression of IFN-γ, CD44, and granzyme B of CD8+ tumor-infiltrating lymphocytes (TILs) were analyzed using flow cytometry. Representative dot plots are shown in the left panel. Results from two independent experiments are depicted as mean ± SEM. Statistical analysis was performed by two-way ANOVA with Sidak’s multiple comparisons or Student’s t-test. (*p<0.05, **p<0.01, ***p<0.001, ****p<0.0001).
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Figure 2—source data 1
Impaired CD8+ T cell function in Asm-deficient tumor-bearing mice upon CD4+ T cell depletion.
- https://cdn.elifesciences.org/articles/83073/elife-83073-fig2-data1-v1.xlsx
Figure 3 with 1 supplement
T cell-specific acid sphingomyelinase (Asm) deficiency leads to reduced CD8+ T cell activation in vitro.
Isolated CD8+ T cells from Smpd1fl/fl/Cd4cre/+ mice (Asm/CD4cre) and Smpd1fl/fl/Cd4+/+ littermates (wildtype [WT]) where either left unstimulated or stimulated with anti-CD3 and anti-CD28 for indicated time points. (A) mRNA expression of Asm (Smpd1) following activation was analyzed by RT-qPCR (n=4–8). (B) Ceramide levels of CD8+ T cells were determined by mass spectrometry (n=4). (C) Expression of CD25, CD69, and CD44 was analyzed by flow cytometry (n=6–7). Representative histograms are shown in the upper panel. (D) OVA-specific cytotoxic lymphocytes were generated and incubated with OVA-peptide 257–264 loaded CFSEhigh-labeled target and unloaded CFSElow-labeled control cells. Specific killing was evaluated by frequencies of target and control populations determined by flow cytometry (n=6–7). Representative histograms are shown in the left panel. (E) Frequencies of granzyme B-expressing CD8+ T cells from Asm/CD4cre mice and WT littermates without and (F) in the presence of C16 ceramide were analyzed by flow cytometry (n=4–8). Representative contour plots are shown in the left panel. Results from two to four independent experiments are depicted as mean ± SEM. Statistical analysis was performed by two-way ANOVA with Sidak’s multiple comparisons, Mann-Whitney U-test, or Student’s t-test. (*p<0.05, **p<0.01, ****p<0.0001).
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Figure 3—source data 1
T cell-specific Asm deficiency leads to reduced CD8+ T cell activation in vitro.
- https://cdn.elifesciences.org/articles/83073/elife-83073-fig3-data1-v1.zip
Figure 3—figure supplement 1
In vitro characterization of acid sphingomyelinase (Asm)-deficient CD4+ T cells.
(A) Isolated CD4+ T cells from Asm/CD4cre mice and wildtype (WT) littermates were either left unstimulated or stimulated with anti-CD3 and anti-CD28 antibodies for indicated time points. mRNA expression of Asm (Smpd1) was analyzed by RT-qPCR (n=6–8). (B) Ceramide levels of unstimulated or anti-CD3/anti-CD28 stimulated (24 hr) CD4+ T cells from Asm/CD4cre mice and WT littermates were determined by mass spectrometry (n=4). (C) Sorted CD4+CD25− T cells from Asm/CD4cre and WT mice were stimulated with anti-CD3 and anti-CD28 antibodies in the presence of IL-2 and TGF-β1 (iTreg). Respective controls (Th0) were only stimulated with anti-CD3 and anti-CD28 antibodies. After 3 days, Treg differentiation was analyzed by Foxp3 expression (n=6–7). Representative dot plots are depicted in the left panel. (D) In order to differentiate naïve CD4+CD25− T cells into Th1 cells, isolated cells were cultured in the presence of anti-CD3, anti-CD28, anti-IL-4, and IL-12 (Th1), or only stimulated with anti-CD3 and anti-CD28 (Th0). After 6 days, Th1 differentiation was assessed by IFN-γ expression (n=5–6). Representative dot plots are shown in the left panel. Results from two to three independent experiments are depicted as mean ± SEM. Statistical analysis was performed by two-way ANOVA with Sidak’s multiple comparisons or Student’s t-test. (*p<0.05, **p<0.01, ****p<0.0001).
Figure 4
Cell-intrinsic acid sphingomyelinase (Asm) activity determines CD8+ T cell activation in vivo.
(A) B16-F1 melanoma cells were transplanted into Asm/CD4cre mice and wildtype (WT) littermates, and tumor growth was monitored when tumors reached a detectable size (n=12–16). (B) Percentages of CD4+ T cells, Foxp3+ Tregs, and CD8+ T cells within dLN and tumor were determined by flow cytometry, and absolute cell numbers were calculated. Representative dot plots are shown in the upper panel. (C) Expression of IFN-γ, TNF-α, and granzyme B of tumor-infiltrating lymphocytes (TILs) was determined by flow cytometry. Results from four independent experiments are depicted as mean ± SEM. Statistical analysis was performed by two-way ANOVA with Sidak’s multiple comparisons, Mann-Whitney U-test, or Student’s t-test. (*p<0.05, **p<0.01, ***p<0.001).
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Figure 4—source data 1
Cell-intrinsic Asm activity determines CD8+ T cell activation in vivo.
- https://cdn.elifesciences.org/articles/83073/elife-83073-fig4-data1-v1.xlsx
Figure 5
Ceramide co-localizes with CD3 and T cell receptor (TCR).
CD8+ T cells were isolated and stimulated with CD3/CD28 MACSiBead particles for 2 hr and stained for ceramide (red) and (A) CD3 or (B) TCR beta (green). Cells were visualized using a Biorevo BZ-9000 fluorescence microscope.
Figure 6 with 1 supplement
Acid ceramidase (Ac)-deficient CD8+ T cells have elevated ceramide levels and show increased activation in vitro.
(A) Isolated CD8+ T cells from Asah1fl/fl/Cd4cre/+ mice (Ac/CD4cre) and Asah1fl/fl/Cd4+/+ littermates (wildtype [WT]) where either left unstimulated or stimulated with anti-CD3 and anti-CD28 for indicated time points. mRNA expression of Ac (Asah1) following activation was analyzed by RT-qPCR (n=3–4). (B) Ceramide levels of CD8+ T cells were determined by mass spectrometry (n=4). (C) For T cell receptor signaling analysis, splenocytes from Ac/CD4cre and WT mice were left unstimulated (0’) or stimulated with anti-CD3 and anti-CD28 for 5 (5’) min. Afterward, samples were analyzed for phospho-ZAP70 of gated ZAP70+CD8+ T cells and phospho-PLCγ of gated CD8+ T cells by flow cytometry (n=4). Representative dot plots and fluorescence minus one (FMOs) for phospho-ZAP70 are shown in the left panel. (D) Western blot analysis of phospho-ZAP70 expression of CD8+ T cells from Ac/CD4cre and WT mice after 5 min of stimulation with anti-CD3 and anti-CD28 (n=3). (E) CD8+ T cells were left untreated as control or stimulated for 24 or 48 hr and analyzed for granzyme B expression by flow cytometry (n=5–8). Representative contour plots are shown in the left panel. (F) Specific killing of antigen-specific cytotoxic lymphocytes from Ac/CD4cre/OTI mice and WT controls was assessed (n=8–9). Representative histograms are shown in the left panel. Data are depicted as mean ± SEM. Statistical analysis was performed by two-way ANOVA with Sidak’s multiple comparisons, Mann-Whitney U-test, or Student’s t-test. (*p<0.05, **p<0.01, ****p<0.0001).
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Figure 6—source data 1
Ac-deficient CD8+ T cells have elevated ceramide levels and show increased activation in vitro.
- https://cdn.elifesciences.org/articles/83073/elife-83073-fig6-data1-v1.zip
Figure 6—figure supplement 1
In vitro characterization of acid ceramidase (Ac)-deficient CD4+ T cells.
(A) Isolated CD4+ T cells from Ac/CD4cre and wildtype (WT) mice were either left unstimulated or stimulated with anti-CD3 and anti-CD28 antibodies for indicated time points. mRNA expression of Ac (Asah1) was analyzed by RT-qPCR (n=3–4). (B) Ceramide levels of unstimulated and anti-CD3/anti-CD28 stimulated (24 hr) CD4+ T cells from Ac/CD4cre and WT mice were determined by mass spectrometry (n=4). (C) For T cell receptor signaling analysis, splenocytes from Ac/CD4cre and WT mice were left unstimulated (0‘) or stimulated with anti-CD3 and anti-CD28 antibodies for 5 (5’) min. Afterward, samples were analyzed for phospho-ZAP70 of gated ZAP70+CD4+ T cells and phospho-PLCγ of gated CD4+ T cells by flow cytometry (n=4–7). Representative dot plots and FMOs are shown in the left panel. (D) In order to differentiate naïve CD4+CD25− T cells from Acflox/flox/CD4cre and WT mice into Th1 cells, isolated cells were cultured in the presence of anti-CD3, anti-CD28, anti-IL-4, and IL-12 (Th1), or only stimulated with anti-CD3 and anti-CD28 antibodies (Th0). After 6 days, cells were analyzed for IFN-γ and granzyme B expression by flow cytometry (n=9). Results from two to three independent experiments are depicted as mean ± SEM. Statistical analysis was performed by two-way ANOVA with Sidak’s multiple comparisons or Student’s t-test. (*p<0.05, **p<0.01, ****p<0.0001).
Figure 7
Synaptic ceramide is elevated in acid ceramidase (Ac)-deficient T cells compared to acid sphingomyelinase (Asm)-deficient T cells.
(A) CD8+ T cells were isolated from Asm/CD4cre or Ac/CD4cre mice and stimulated with CD3/CD28 MACSiBead particles for 2 hr and stained for ceramide (red) and T cell receptor beta (green). Cells were visualized using a Biorevo BZ-9000 fluorescence microscope. (B) The ceramide signal was quantified in the synapse and in the back of cell, and the ratio of the signals was calculated (n=35–45). Data are depicted as boxplot with min/max whiskers. Statistical analysis was performed by Student’s t-test. (****p<0.0001).
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Figure 7—source data 1
Synaptic ceramide is elevated in Ac-deficient T cells compared to Asm-deficient T cells.
- https://cdn.elifesciences.org/articles/83073/elife-83073-fig7-data1-v1.xlsx
Figure 8
Elevated anti-tumor immune response in T cell-specific acid ceramidase (Ac)-deficient mice.
(A) B16-F1 melanoma cells were transplanted into Ac/CD4cre mice and wildtype (WT) littermates. Tumor volume was monitored once tumors have been established (n=8–10). (B) Percentages of CD4+ T cells, Foxp3+ Tregs, and CD8+ T cells were determined by flow cytometry, and absolute cell numbers were calculated. (C) Frequencies of IFN-γ+ and granzyme B+ tumor-infiltrating lymphocytes (TILs) were determined by flow cytometry. Results from two independent experiments are depicted as mean ± SEM. Statistical analysis was performed by two-way ANOVA with Sidak’s multiple comparisons or Student’s t-test. (*p<0.05, **p<0.01, ****p<0.0001).
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Figure 8—source data 1
Figure 8 Elevated anti-tumor immune response in T cell-specific Ac-deficient mice.
- https://cdn.elifesciences.org/articles/83073/elife-83073-fig8-data1-v1.xlsx
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Cell-intrinsic ceramides determine T cell function during melanoma progression
eLife 11:e83073.
https://doi.org/10.7554/eLife.83073
