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STAT1-dependent signal integration between IFNγ and TLR4 in vascular cells reflect pro-atherogenic responses in human atherosclerosis.

Chmielewski S, Olejnik A, Sikorski K, Pelisek J, Błaszczyk K, Aoqui C, Nowicka H, Zernecke A, Heemann U, Wesoly J, Baumann M, Bluyssen HA - PLoS ONE (2014)

Bottom Line: The synergistic interactions between IFNγ and TLR4 also resulted in increased T-cell migration and impaired aortic contractility in a STAT1-dependent manner.Expression of the chemokines CXCL9 and CXCL10 correlated with STAT1 phosphorylation in vascular cells in plaques from human carotid arteries.Moreover, using data mining of human plaque transcriptomes, expression of a selection of these STAT1-dependent pro-atherogenic genes was found to be increased in coronary artery disease (CAD) and carotid atherosclerosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Nephrology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany; Department of Human Molecular Genetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University Poznan, Poznan, Poland.

ABSTRACT
Signal integration between IFNγ and TLRs in immune cells has been associated with the host defense against pathogens and injury, with a predominant role of STAT1. We hypothesize that STAT1-dependent transcriptional changes in vascular cells involved in cross-talk between IFNγ and TLR4, reflect pro-atherogenic responses in human atherosclerosis. Genome-wide investigation identified a set of STAT1-dependent genes that were synergistically affected by interactions between IFNγ and TLR4 in VSMCs. These included the chemokines Cxcl9, Ccl12, Ccl8, Ccrl2, Cxcl10 and Ccl5, adhesion molecules Cd40, Cd74, and antiviral and antibacterial genes Rsad2, Mx1, Oasl1, Gbp5, Nos2, Batf2 and Tnfrsf11a. Among the amplified genes was also Irf8, of which Ccl5 was subsequently identified as a new pro-inflammatory target in VSMCs and ECs. Promoter analysis predicted transcriptional cooperation between STAT1, IRF1, IRF8 and NFκB, with the novel role of IRF8 providing an additional layer to the overall complexity. The synergistic interactions between IFNγ and TLR4 also resulted in increased T-cell migration and impaired aortic contractility in a STAT1-dependent manner. Expression of the chemokines CXCL9 and CXCL10 correlated with STAT1 phosphorylation in vascular cells in plaques from human carotid arteries. Moreover, using data mining of human plaque transcriptomes, expression of a selection of these STAT1-dependent pro-atherogenic genes was found to be increased in coronary artery disease (CAD) and carotid atherosclerosis. Our study provides evidence to suggest that in ECs and VSMCs STAT1 orchestrates a platform for cross-talk between IFNγ and TLR4, and identifies a STAT1-dependent gene signature that reflects a pro-atherogenic state in human atherosclerosis.

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Identification of genes prone to synergistic amplification upon treatment with IFNγ and LPS.WT and STAT1−/− VSMCs were treated as described in Fig. 1. On RNA isolated from untreated or IFNγ, LPS or IFNγ+LPS treated VSMCs genome-wide expression profiling was performed. A, Venn diagrams revealing number of differentially expressed genes upon stimulation. B, Heat map of the expression of synergistically amplified genes in WT and STAT1−/−VSMCs. C, Clustering of the synergistically upregulated genes according to their expression profile. AVG, average expression in the group. For details see text.
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pone-0113318-g002: Identification of genes prone to synergistic amplification upon treatment with IFNγ and LPS.WT and STAT1−/− VSMCs were treated as described in Fig. 1. On RNA isolated from untreated or IFNγ, LPS or IFNγ+LPS treated VSMCs genome-wide expression profiling was performed. A, Venn diagrams revealing number of differentially expressed genes upon stimulation. B, Heat map of the expression of synergistically amplified genes in WT and STAT1−/−VSMCs. C, Clustering of the synergistically upregulated genes according to their expression profile. AVG, average expression in the group. For details see text.

Mentions: Next, we compared genome-wide transcriptional responses of WT-VSMCs to LPS (4 h) or IFNγ (8 h) alone, or after combined treatment (IFNγ 8 h, LPS 4 h). IFNγ changed the expression of 297 and LPS of 553 genes under these conditions (Fig. 2A). The interactions between IFNγ and LPS (Fig. 2A) increased the number of up-regulated genes to 990. While 128 of the IFNγ-regulated genes were modulated by LPS (Fig. 2A), 118 were also commonly regulated by IFNγ+LPS. Likewise, we compared transcriptional responses of STAT1−/−-VSMCs to LPS or IFNγ alone, or after combined treatment. Only 16 genes were found to be up-regulated by IFNγ in STAT1−/−-VSMCs, highlighting the importance of STAT1 in this response pathway. In contrast, LPS treatment of STAT1−/−-VSMCs was similar to WT-VSMCs, with a total of 470 genes being modulated. However, in general the potency of the response was lower as compared to WT-VSMCs. Consequently, the additive or synergistic effect of IFNγ and LPS as seen in WT-VSMCs, was no longer present in STAT1−/−-VSMCs. Only 493 genes were upregulated by IFNγ+LPS, of which 323 were in common with LPS alone. The complete list of up and down-regulated genes in response to IFNγ or LPS alone, or after combined treatment is shown in Table S1, S2 and S3, respectively.


STAT1-dependent signal integration between IFNγ and TLR4 in vascular cells reflect pro-atherogenic responses in human atherosclerosis.

Chmielewski S, Olejnik A, Sikorski K, Pelisek J, Błaszczyk K, Aoqui C, Nowicka H, Zernecke A, Heemann U, Wesoly J, Baumann M, Bluyssen HA - PLoS ONE (2014)

Identification of genes prone to synergistic amplification upon treatment with IFNγ and LPS.WT and STAT1−/− VSMCs were treated as described in Fig. 1. On RNA isolated from untreated or IFNγ, LPS or IFNγ+LPS treated VSMCs genome-wide expression profiling was performed. A, Venn diagrams revealing number of differentially expressed genes upon stimulation. B, Heat map of the expression of synergistically amplified genes in WT and STAT1−/−VSMCs. C, Clustering of the synergistically upregulated genes according to their expression profile. AVG, average expression in the group. For details see text.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4257532&req=5

pone-0113318-g002: Identification of genes prone to synergistic amplification upon treatment with IFNγ and LPS.WT and STAT1−/− VSMCs were treated as described in Fig. 1. On RNA isolated from untreated or IFNγ, LPS or IFNγ+LPS treated VSMCs genome-wide expression profiling was performed. A, Venn diagrams revealing number of differentially expressed genes upon stimulation. B, Heat map of the expression of synergistically amplified genes in WT and STAT1−/−VSMCs. C, Clustering of the synergistically upregulated genes according to their expression profile. AVG, average expression in the group. For details see text.
Mentions: Next, we compared genome-wide transcriptional responses of WT-VSMCs to LPS (4 h) or IFNγ (8 h) alone, or after combined treatment (IFNγ 8 h, LPS 4 h). IFNγ changed the expression of 297 and LPS of 553 genes under these conditions (Fig. 2A). The interactions between IFNγ and LPS (Fig. 2A) increased the number of up-regulated genes to 990. While 128 of the IFNγ-regulated genes were modulated by LPS (Fig. 2A), 118 were also commonly regulated by IFNγ+LPS. Likewise, we compared transcriptional responses of STAT1−/−-VSMCs to LPS or IFNγ alone, or after combined treatment. Only 16 genes were found to be up-regulated by IFNγ in STAT1−/−-VSMCs, highlighting the importance of STAT1 in this response pathway. In contrast, LPS treatment of STAT1−/−-VSMCs was similar to WT-VSMCs, with a total of 470 genes being modulated. However, in general the potency of the response was lower as compared to WT-VSMCs. Consequently, the additive or synergistic effect of IFNγ and LPS as seen in WT-VSMCs, was no longer present in STAT1−/−-VSMCs. Only 493 genes were upregulated by IFNγ+LPS, of which 323 were in common with LPS alone. The complete list of up and down-regulated genes in response to IFNγ or LPS alone, or after combined treatment is shown in Table S1, S2 and S3, respectively.

Bottom Line: The synergistic interactions between IFNγ and TLR4 also resulted in increased T-cell migration and impaired aortic contractility in a STAT1-dependent manner.Expression of the chemokines CXCL9 and CXCL10 correlated with STAT1 phosphorylation in vascular cells in plaques from human carotid arteries.Moreover, using data mining of human plaque transcriptomes, expression of a selection of these STAT1-dependent pro-atherogenic genes was found to be increased in coronary artery disease (CAD) and carotid atherosclerosis.

View Article: PubMed Central - PubMed

Affiliation: Department of Nephrology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany; Department of Human Molecular Genetics, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University Poznan, Poznan, Poland.

ABSTRACT
Signal integration between IFNγ and TLRs in immune cells has been associated with the host defense against pathogens and injury, with a predominant role of STAT1. We hypothesize that STAT1-dependent transcriptional changes in vascular cells involved in cross-talk between IFNγ and TLR4, reflect pro-atherogenic responses in human atherosclerosis. Genome-wide investigation identified a set of STAT1-dependent genes that were synergistically affected by interactions between IFNγ and TLR4 in VSMCs. These included the chemokines Cxcl9, Ccl12, Ccl8, Ccrl2, Cxcl10 and Ccl5, adhesion molecules Cd40, Cd74, and antiviral and antibacterial genes Rsad2, Mx1, Oasl1, Gbp5, Nos2, Batf2 and Tnfrsf11a. Among the amplified genes was also Irf8, of which Ccl5 was subsequently identified as a new pro-inflammatory target in VSMCs and ECs. Promoter analysis predicted transcriptional cooperation between STAT1, IRF1, IRF8 and NFκB, with the novel role of IRF8 providing an additional layer to the overall complexity. The synergistic interactions between IFNγ and TLR4 also resulted in increased T-cell migration and impaired aortic contractility in a STAT1-dependent manner. Expression of the chemokines CXCL9 and CXCL10 correlated with STAT1 phosphorylation in vascular cells in plaques from human carotid arteries. Moreover, using data mining of human plaque transcriptomes, expression of a selection of these STAT1-dependent pro-atherogenic genes was found to be increased in coronary artery disease (CAD) and carotid atherosclerosis. Our study provides evidence to suggest that in ECs and VSMCs STAT1 orchestrates a platform for cross-talk between IFNγ and TLR4, and identifies a STAT1-dependent gene signature that reflects a pro-atherogenic state in human atherosclerosis.

Show MeSH
Related in: MedlinePlus