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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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CXCL10 amplified by IFNγ and LPS in VSMCs is STAT1 dependent.A, WT and STAT1−/− VSMCs were treated with 10 ng/ml IFNγ for 8 h or with 1 ug/ml of LPS for 4 h or with IFNγ for 4 h followed by LPS for additional 4 h. RNA was isolated and qRT-PCR for Cxcl10 using Gapdh as internal control was performed. B, Cells were treated as in A. On the medium remained after treatment ELISA for CXCL10 was performed. Data represent means of at least 3 independent biological experiments ±SEM and p<0.05 was considered as significant. Data were tested for significance by one-way ANOVA followed by post-hoc Tukey or unpaired two-tailed student T-test when appropriate.
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pone-0113318-g001: CXCL10 amplified by IFNγ and LPS in VSMCs is STAT1 dependent.A, WT and STAT1−/− VSMCs were treated with 10 ng/ml IFNγ for 8 h or with 1 ug/ml of LPS for 4 h or with IFNγ for 4 h followed by LPS for additional 4 h. RNA was isolated and qRT-PCR for Cxcl10 using Gapdh as internal control was performed. B, Cells were treated as in A. On the medium remained after treatment ELISA for CXCL10 was performed. Data represent means of at least 3 independent biological experiments ±SEM and p<0.05 was considered as significant. Data were tested for significance by one-way ANOVA followed by post-hoc Tukey or unpaired two-tailed student T-test when appropriate.

Mentions: Total RNA was isolated from VSMCs and ECs using RNAeasy Mini Kit (Qiagen, 74104) together with DNAse digestion step according to the manufacture's protocol. Isolated aortas were cleaned from perivascular fat and incubated as depicted in Fig. 1. After stimulation aortas were snap frozen on liquid nitrogen, ground up with a pestle and resuspended in 1 ml of Trizol. Total RNA was isolated using Trizol method followed by PureLink RNA kit (Life Technologies, 12183018A). Complementary DNA was synthesized using iScript cDNA Synthesis Kit (BioRad, 170-881), according to manufacturer's protocol. Quantitative reverse transcriptase PCR (qRT-PCR) was performed using SSoFast Evagreen (MyiQ ICycler, Bio-Rad, 172-5201). Forward and reverse primers are depicted in Table S4. The 2−ddCt method was applied for quantification [21]. Fold change in the target gene were normalized to GAPDH and relative to the mean expression at untreated sample. The results are expressed as fold of control from at least 3 independent assays.


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)

CXCL10 amplified by IFNγ and LPS in VSMCs is STAT1 dependent.A, WT and STAT1−/− VSMCs were treated with 10 ng/ml IFNγ for 8 h or with 1 ug/ml of LPS for 4 h or with IFNγ for 4 h followed by LPS for additional 4 h. RNA was isolated and qRT-PCR for Cxcl10 using Gapdh as internal control was performed. B, Cells were treated as in A. On the medium remained after treatment ELISA for CXCL10 was performed. Data represent means of at least 3 independent biological experiments ±SEM and p<0.05 was considered as significant. Data were tested for significance by one-way ANOVA followed by post-hoc Tukey or unpaired two-tailed student T-test when appropriate.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0113318-g001: CXCL10 amplified by IFNγ and LPS in VSMCs is STAT1 dependent.A, WT and STAT1−/− VSMCs were treated with 10 ng/ml IFNγ for 8 h or with 1 ug/ml of LPS for 4 h or with IFNγ for 4 h followed by LPS for additional 4 h. RNA was isolated and qRT-PCR for Cxcl10 using Gapdh as internal control was performed. B, Cells were treated as in A. On the medium remained after treatment ELISA for CXCL10 was performed. Data represent means of at least 3 independent biological experiments ±SEM and p<0.05 was considered as significant. Data were tested for significance by one-way ANOVA followed by post-hoc Tukey or unpaired two-tailed student T-test when appropriate.
Mentions: Total RNA was isolated from VSMCs and ECs using RNAeasy Mini Kit (Qiagen, 74104) together with DNAse digestion step according to the manufacture's protocol. Isolated aortas were cleaned from perivascular fat and incubated as depicted in Fig. 1. After stimulation aortas were snap frozen on liquid nitrogen, ground up with a pestle and resuspended in 1 ml of Trizol. Total RNA was isolated using Trizol method followed by PureLink RNA kit (Life Technologies, 12183018A). Complementary DNA was synthesized using iScript cDNA Synthesis Kit (BioRad, 170-881), according to manufacturer's protocol. Quantitative reverse transcriptase PCR (qRT-PCR) was performed using SSoFast Evagreen (MyiQ ICycler, Bio-Rad, 172-5201). Forward and reverse primers are depicted in Table S4. The 2−ddCt method was applied for quantification [21]. Fold change in the target gene were normalized to GAPDH and relative to the mean expression at untreated sample. The results are expressed as fold of control from at least 3 independent assays.

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