Overexpression of TET1s promoted sFRP-1 expression in endothelial cells. (a) Enzyme-linked immunosorbent assay (ELISA) was used to detect the level of sFRP-1 in plasma of WT mice, TET1cs/cs mice, and TET1−/− mice (n = 13). (b) Quantitative PCR detected the relative mRNA levels of sFRP-1 in ECs from the aorta of WT mice, TET1cs/cs mice, and TET1−/− mice (n = 13). (c)–(g) HUVECs were transfected with TET1-overexpressed adenovirus or control adenovirus and loaded with OSS for 48 h. (c) Quantitative PCR was performed to detect the relative mRNA level of sFRP-1. (d) and (e) Western blotting was performed to detect the protein expression levels of TET1-FL, TET1s, and sFRP-1 (n = 6). (f) ELISA was used to detect the level of sFRP-1 in the medium (n = 6). (g) and (h) Co-IP was used to detect the interaction of Fzd4 with sFRP-1 (n = 4). All data were presented as mean ± SD. * P < 0.05, ** P < 0.01, and **** P < 0.0001.