Semaphorin 7A knockdown improves injury and prevents endothelial-to-mesenchymal transition in ox-LDL-induced HUVECs by regulating β1 integrin expression.

Abstract

Atherosclerosis is the most common cause of cardiovascular disease and is accompanied by high mortality rates and a poor prognosis. Semaphorin 7A (Sema7A) and its receptor β1 integrin have been reported to participate in the development of atherosclerosis. However, the role of Sema7A and β1 integrin in endothelial cell injury and endothelial-to-mesenchymal transition (EMT) in atherosclerosis remains undetermined, to the best of our knowledge. The mRNA and protein expression levels of Sema7A and β1 integrin in HUVECs were analyzed using reverse transcription-quantitative PCR (RT-qPCR) and western blot analyses, respectively. HUVECs were induced with 50 µg/ml oxidized low-density lipoprotein (ox-LDL) to establish an atherosclerosis cell model. Cell viability was measured using Cell Counting Kit-8 assay and the production of IL-1β, IL-6 and C-C motif chemokine ligand 2 was determined using ELISA. The expression levels of cell adhesion factors, intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 were analyzed using RT-qPCR and western blot analyses. Cell apoptosis was detected using flow cytometry and western blotting. The levels of EMT-related markers were evaluated using RT-qPCR, western blotting and immunofluorescence staining. The results of the present study revealed that the expression levels of Sema7A and β1 integrin were significantly upregulated in ox-LDL-treated HUVECs. Treatment with ox-LDL significantly decreased cell viability, and increased the levels of inflammatory and adhesion factors, the cell apoptotic rate and the expression levels of EMT-related proteins. Knockdown of Sema7A reversed the ox-LDL-induced inflammatory responses and EMT, while the overexpression of β1 integrin reversed the Sema7A-mediated inhibitory effects on ox-LDL-treated HUVECs. In conclusion, the findings of the present study indicated that Sema7A and β1 integrin may play significant roles in atherosclerosis by mediating endothelial cell injury and EMT progression.