Omentin-1 ameliorates the attachment of the leukocyte THP-1 cells to HUVECs by targeting the transcriptional factor KLF2

Highlights: • Omentin-1 inhibited ox-LDL-induced THP-1 attachment to HUVECs. • Omentin-1 mitigated ox-LDL-induced expression of VCAM-1 and E-selectin. • Omentin-1 attenuated ox-LDL-induced reduction of KLF2 and its target genes. • The effects of omentin-1 on the expression of KLF2 are mediated by p53. Oxidation of low-density lipoproteins (ox-LDL) plays a critical role in endothelial dysfunction and the pathological progression of atherosclerosis by causing leukocyte attachment to endothelial surfaces. Omentin-1, an important adipokine primarily secreted by stromal vascular cells, has displayed various biological functions in diverse tissues. However, little information regarding the effects of omentin-1 on ox-LDL- induced endothelial dysfunction has been reported before. In the current study, we found that omentin-1 significantly reduced the attachment of the leukocyte THP-1 cells to human umbilical vein endothelial cells (HUVECs) in a dose dependent manner. Additionally, omentin-1 treatment prevented the expression of cell adhesion molecules such as VCAM-1 and E-selectin at both the mRNA level and the protein level. Notably, we found that omentin-1 significantly restored ox-LDL-induced reduction of KLF2, an important transcriptional factor and regulator of endothelial function. Also, omentin-1 promoted the expression of KLF2 target genes eNOS and PAI-1. Mechanistically, our results indicate that the effects of omentin-1 on KLF2 expression are mediated by p53. These results highlight the potential of omentin-1 in preventing endothelial dysfunction and atherosclerosis.