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γδT cells are prevalent in the proximal aorta and drive nascent atherosclerotic lesion progression and neutrophilia in hypercholesterolemic mice.

Vu DM, Tai A, Tatro JB, Karas RH, Huber BT, Beasley D - PLoS ONE (2014)

Bottom Line: These aortic γδT cells produced IL-17, but not IFN-γ, analyzed by ex vivo FACS.In addition, circulating neutrophils were drastically reduced in these DKO mice on Western diet, while expansion of inflammatory monocytes and splenic Th1 or Th17 lymphocytes was not affected.Targeting γδT cells thus might offer therapeutic benefit in atherosclerosis or other inflammatory vascular diseases.

View Article: PubMed Central - PubMed

Affiliation: Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, United States of America.

ABSTRACT
Unique innate immunity-linked γδT cells have been seen in early human artery lesions, but their role in lesion development has received little attention. Here we investigated whether γδT cells modulate atherogenesis in apolipoprotein E-deficient (ApoE KO) mice. We found that γδT cell numbers were markedly increased in the proximal aorta of ApoE-deficient vs. wild-type mice during early atherogenesis, particularly in the aortic root and arch, where they comprised most of the T cells and lesion progression is most rapid. γδT cells infiltrated intimal lesions in ApoE KO mice, but only the adventitia in wild-type mice, and were more prevalent than CD4+ T cells in early nascent lesions, as evaluated by en face confocal microscopy. These aortic γδT cells produced IL-17, but not IFN-γ, analyzed by ex vivo FACS. Furthermore, aortic arch lipid accumulation correlated strongly with abundance of IL-17-expressing splenic γδT cells in individual ApoE KO mice. To investigate the role of these γδT cells in early atherogenesis, we analyzed ApoE/γδT double knockout (DKO) compared to ApoE KO mice. We observed reduced early intimal lipid accumulation at sites of nascent lesion formation, both in chow-fed (by 40%) and Western diet-fed (by 44%) ApoE/γδT DKO mice. In addition, circulating neutrophils were drastically reduced in these DKO mice on Western diet, while expansion of inflammatory monocytes and splenic Th1 or Th17 lymphocytes was not affected. These data reveal, for the first time, a pathogenic role of γδT cells in early atherogenesis in ApoE KO mice, by mechanisms likely to involve their IL-17 production and induction of neutrophilia. Targeting γδT cells thus might offer therapeutic benefit in atherosclerosis or other inflammatory vascular diseases.

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γδT cells are the dominant T cell subset in early lesions and associated adventitia of ApoE KO mice.En face confocal images of aortic tissue from Western diet-fed ApoE KO mice stained with anti-CD3-FITC (green), anti-TCRγδ APC (red), and DAPI (blue). γδT cells constitute the majority of CD3+ T cells in aortic root intima (A) and adventitia (B). γδT cells infiltrate the adventitia at intercostal artery branch points of the descending thoracic aorta (C). White scale bar = 10 µm. D: Quantitation: n = 3.
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pone-0109416-g002: γδT cells are the dominant T cell subset in early lesions and associated adventitia of ApoE KO mice.En face confocal images of aortic tissue from Western diet-fed ApoE KO mice stained with anti-CD3-FITC (green), anti-TCRγδ APC (red), and DAPI (blue). γδT cells constitute the majority of CD3+ T cells in aortic root intima (A) and adventitia (B). γδT cells infiltrate the adventitia at intercostal artery branch points of the descending thoracic aorta (C). White scale bar = 10 µm. D: Quantitation: n = 3.

Mentions: Considering the marked enrichment of γδT cells in proximal aorta of ApoE KO vs. B6 mice, we determined the precise location of T cells within intima and adventitia, by en face confocal immunostaining. γδTcells (CD3+TCRγδ+) were clearly distinguishable from conventional αβT cells (CD3+TCRγδ−) cells (Fig. S2), and were absent from aortas of ApoE/TCRδ DKO mice (not shown), confirming the specificity of the staining. Remarkably, most aortic root T cells associated with early lesions were γδT cells, constituting 72% of intimal T cells and 97% of adventitial T cells of Western diet-fed ApoE KO mice (Fig. 2A, B, D). In contrast, both CD4+ and CD3+TCRγδ− cells constituted only ∼20% of early intimal T cells (Fig. 2D, S3), and were rare in the adventitia. No γδT cells were found to express CD4 (Fig. S3). γδT cells, although more prevalent in the aortic root, were also found in aortic arch lesions and adjacent adventitia (not shown). In the thoracic descending aorta, γδT cells were not found in the intima, and within the adventitia they were only found at intercostal artery branch points (Fig. 2C), sites prone to lesion formation [31]. In wild-type mice, γδT cells were less abundant, found mostly in adventitia at the base of the aortic root, but only rarely in intima (not shown). γδT cells were also present in advanced lesions of aged chow-fed ApoE KO mice, but CD4+ T cells were somewhat more prevalent at this stage (Fig. S4). These results show that γδT cells are present in early stage atherosclerotic lesions of the aortic root and arch of ApoE KO mice.


γδT cells are prevalent in the proximal aorta and drive nascent atherosclerotic lesion progression and neutrophilia in hypercholesterolemic mice.

Vu DM, Tai A, Tatro JB, Karas RH, Huber BT, Beasley D - PLoS ONE (2014)

γδT cells are the dominant T cell subset in early lesions and associated adventitia of ApoE KO mice.En face confocal images of aortic tissue from Western diet-fed ApoE KO mice stained with anti-CD3-FITC (green), anti-TCRγδ APC (red), and DAPI (blue). γδT cells constitute the majority of CD3+ T cells in aortic root intima (A) and adventitia (B). γδT cells infiltrate the adventitia at intercostal artery branch points of the descending thoracic aorta (C). White scale bar = 10 µm. D: Quantitation: n = 3.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4196850&req=5

pone-0109416-g002: γδT cells are the dominant T cell subset in early lesions and associated adventitia of ApoE KO mice.En face confocal images of aortic tissue from Western diet-fed ApoE KO mice stained with anti-CD3-FITC (green), anti-TCRγδ APC (red), and DAPI (blue). γδT cells constitute the majority of CD3+ T cells in aortic root intima (A) and adventitia (B). γδT cells infiltrate the adventitia at intercostal artery branch points of the descending thoracic aorta (C). White scale bar = 10 µm. D: Quantitation: n = 3.
Mentions: Considering the marked enrichment of γδT cells in proximal aorta of ApoE KO vs. B6 mice, we determined the precise location of T cells within intima and adventitia, by en face confocal immunostaining. γδTcells (CD3+TCRγδ+) were clearly distinguishable from conventional αβT cells (CD3+TCRγδ−) cells (Fig. S2), and were absent from aortas of ApoE/TCRδ DKO mice (not shown), confirming the specificity of the staining. Remarkably, most aortic root T cells associated with early lesions were γδT cells, constituting 72% of intimal T cells and 97% of adventitial T cells of Western diet-fed ApoE KO mice (Fig. 2A, B, D). In contrast, both CD4+ and CD3+TCRγδ− cells constituted only ∼20% of early intimal T cells (Fig. 2D, S3), and were rare in the adventitia. No γδT cells were found to express CD4 (Fig. S3). γδT cells, although more prevalent in the aortic root, were also found in aortic arch lesions and adjacent adventitia (not shown). In the thoracic descending aorta, γδT cells were not found in the intima, and within the adventitia they were only found at intercostal artery branch points (Fig. 2C), sites prone to lesion formation [31]. In wild-type mice, γδT cells were less abundant, found mostly in adventitia at the base of the aortic root, but only rarely in intima (not shown). γδT cells were also present in advanced lesions of aged chow-fed ApoE KO mice, but CD4+ T cells were somewhat more prevalent at this stage (Fig. S4). These results show that γδT cells are present in early stage atherosclerotic lesions of the aortic root and arch of ApoE KO mice.

Bottom Line: These aortic γδT cells produced IL-17, but not IFN-γ, analyzed by ex vivo FACS.In addition, circulating neutrophils were drastically reduced in these DKO mice on Western diet, while expansion of inflammatory monocytes and splenic Th1 or Th17 lymphocytes was not affected.Targeting γδT cells thus might offer therapeutic benefit in atherosclerosis or other inflammatory vascular diseases.

View Article: PubMed Central - PubMed

Affiliation: Molecular Cardiology Research Institute, Tufts Medical Center, Boston, Massachusetts, United States of America.

ABSTRACT
Unique innate immunity-linked γδT cells have been seen in early human artery lesions, but their role in lesion development has received little attention. Here we investigated whether γδT cells modulate atherogenesis in apolipoprotein E-deficient (ApoE KO) mice. We found that γδT cell numbers were markedly increased in the proximal aorta of ApoE-deficient vs. wild-type mice during early atherogenesis, particularly in the aortic root and arch, where they comprised most of the T cells and lesion progression is most rapid. γδT cells infiltrated intimal lesions in ApoE KO mice, but only the adventitia in wild-type mice, and were more prevalent than CD4+ T cells in early nascent lesions, as evaluated by en face confocal microscopy. These aortic γδT cells produced IL-17, but not IFN-γ, analyzed by ex vivo FACS. Furthermore, aortic arch lipid accumulation correlated strongly with abundance of IL-17-expressing splenic γδT cells in individual ApoE KO mice. To investigate the role of these γδT cells in early atherogenesis, we analyzed ApoE/γδT double knockout (DKO) compared to ApoE KO mice. We observed reduced early intimal lipid accumulation at sites of nascent lesion formation, both in chow-fed (by 40%) and Western diet-fed (by 44%) ApoE/γδT DKO mice. In addition, circulating neutrophils were drastically reduced in these DKO mice on Western diet, while expansion of inflammatory monocytes and splenic Th1 or Th17 lymphocytes was not affected. These data reveal, for the first time, a pathogenic role of γδT cells in early atherogenesis in ApoE KO mice, by mechanisms likely to involve their IL-17 production and induction of neutrophilia. Targeting γδT cells thus might offer therapeutic benefit in atherosclerosis or other inflammatory vascular diseases.

Show MeSH
Related in: MedlinePlus