FABP4 Inhibitor Alleviates Lipopolysaccharide-Induced HUVEC Injury by Inactivating NF-κB and Activating PPARγ

The study aims to examine the effect of FABP4 on inflammatory response and angiogenesis in the cell model of atherosclerosis and to explore its potential mechanism.Using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting, the mRNA and protein levels of FABP4 in human umbilical vein endothelial cells (HUVECs) treated with lipopolysaccharide (LPS) or oxidized low-density lipoprotein for 6, 12, 24, or 48 hours were measured. To silence FABP4 expression and NF-κB signaling in HUVECs, FABP4 inhibitor and NF-κB inhibitor were utilized. To assess cell survival rate and apoptosis, methyl thiazolyl tetrazolium assays and flow cytometry analysis were conducted. Genes related to cholesterol metabolism, including LOX-1, ABCA1, and ABCG1, were subjected to RT-qPCR and western blotting. Moreover, protein levels of apoptotic markers (Bcl-2 and Bax), PPARγ, the phosphorylated levels of NF-κB p65, and angiogenetic markers (ICAM1, VCAM1, and VEGF) were quantified via western blotting. Using an enzyme-linked immunosorbent assay, concentrations of inflammatory cytokines in HUVECs were measured.FABP4 expression was upregulated in LPS-stimulated HUVECs. The silencing of FABP4 lowered LOX-1 and p65 levels while upregulating ABCA1 and ABCG1 expression in the context of LPS. Furthermore, the inhibition of FABP4 or NF-κB signaling promoted the growth of HUVECs, upregulated Bcl-2 and PPARγ protein levels, and reduced Bax levels, angiogenetic markers, and inflammatory cytokines in the context of LPS. The combination of FABP4 inhibitor and NF-κB inhibitor treatment amplified the above-mentioned effects on cell growth, angiogenesis, and inflammation.Inhibition of FABP4 reduces LPS-induced HUVEC cell damage via the inactivation of NF-κB p65 and activation of PPARγ signaling.