Inhibitory Effect of Essential Oil From Fructus of Alpinia zerumbet on Endothelial-to-Mesenchymal Transformation Induced by TGF-β 1 and Downregulation of KLF4

Essential oil from fructus of Alpinia zerumbet (EOFAZ) protects vascular endothelial cell (VEC) injury. Stimulation and injury factors can induce phenotypic changes in VECs and the occurrence of endothelial-mesenchymal transformation (EndMT), accelerating the occurrence and development of cardiovascular diseases. We investigated the role of EOFAZ in EndMT induced by transforming growth factor-β1 (TGF-β1). All experiments were performed using human umbilical vein endothelial cells (HUVECs). HUVECs were preincubated with EOFAZ for 2 hours and then coincubated with TGF-β1 for 72 hours. Krüpple-like factor 4 (KLF4) was inhibited by small interfering RNA or overexpressed by adenovirus infection. Wound healing, transwell, and angiogenesis assays were used to evaluate the migration ability of HUVECs. Quantitative RT-PCR and Western blotting were used for mRNA and protein expression analyses, respectively. Immunofluorescence staining was used to detect expression of related markers. A coimmunoprecipitation assay verified the interaction between KLF4 and acetylated histone H3. TGF-β1 contributed to EndMT in HUVECs in a time-dependent manner, mainly manifested as an increase in cell migration ability and changes in the expression of EndMT-related mRNAs and proteins. EOFAZ could inhibit EndMT induced by TGF-β1. The results after transfection with siKLF4 were similar to those of EOFAZ treatment. After EOFAZ treatment, the expression of KLF4 and acetylated histone H3 decreased, and protein interactions between them decreased, while expression of the Notch/Snail signal axis decreased. EOFAZ can attenuate endothelial injuries and suppress EndMT in HUVECs under TGF-β1 stimulation conditions because it may downregulate KLF4, decrease histone H3 acetylation, and inhibit the transduction of the Notch/Snail signaling axis.