TSLPR deficiency attenuates atherosclerotic lesion development associated with the inhibition of TH17 cells and the promotion of regulator T cells in ApoE-deficient mice.

AIMS: We generated thymic stromal lymphopoietin R-chain deficient apolipoprotein E-double knockout (ApoE-TSLPR DKO) mice to directly explore the role of thymic stromal lymphopoietin (TSLP) in atherogenesis. METHODS AND RESULTS: Both thymic stromal lymphopoietin (TSLP) and its receptor are expressed in atherosclerotic aortas of apolipoprotein E knockout (ApoE KO) mice. Serum thymic stromal lymphopoietin (TSLP) is markedly increased in apolipoprotein E knockout (ApoE KO) mice fed with a high fat diet (HFD). Arterial lesion formation was significantly decreased in thymic stromal lymphopoietin R-chain deficient apolipoprotein E-double knockout (ApoE-TSLPR DKO) mice compared with apolipoprotein E knockout (ApoE KO) mice. Bone marrow chimera studies indicated reduced lesions in apolipoprotein E knockout (ApoE KO) mice which received the bone marrow of thymic stromal lymphopoietin R-chain deficient apolipoprotein E-double knockout (ApoE-TSLPR DKO) mice as well as in TSLPR KO mice which received bone marrow of ApoE-TSLPR DKO mice. Compared with apolipoprotein E knockout (ApoE KO) mice, IFN-γ secretion by activated T cells was increased but IL-4 expression was reduced in thymic stromal lymphopoietin R-chain deficient apolipoprotein E-double knockout (ApoE-TSLPR DKO) mice. Consisted with these results, the mRNA of IFN-γ was increased but IL-4 was reduced in root. These findings suggest that a reduction in atherosclerotic lesions in thymic stromal lymphopoietin R-chain deficient apolipoprotein E-double knockout (ApoE-TSLPR DKO) mice may not be due to a Th1/Th2 imbalance. On the other hand, the number of Th17 cells, the secretion of IL-17A by activated CD4(+) T cells and the mRNA expression of IL-17A in root were decreased in thymic stromal lymphopoietin R-chain deficient apolipoprotein E-double knockout (ApoE-TSLPR DKO) mice. Notably, the number of regulatory T cell expression of IL-10 was increased in thymic stromal lymphopoietin R-chain deficient apolipoprotein E-double knockout (ApoE-TSLPR DKO) mice. CONCLUSIONS: Collectively, our data suggest that activating thymic stromal lymphopoietin (TSLP) promotes atherosclerosis by inducing Th17/Treg imbalance through thymic stromal lymphopoietin/thymic stromal lymphopoietin R-receptor (TSLP/TSLPR) signal way in apolipoprotein E-deficient mice fed with HFD model.