Free fatty acids stabilize integrin βvia S-nitrosylation to promote monocyte-endothelial adhesion.

Hyperlipidemia characterized by high blood levels of free fatty acids (FFAs) is important for the progression of inflammatory cardiovascular diseases. Integrin β is a transmembrane receptor that drives various cellular functions, including differentiation, migration, and phagocytosis. However, the underlying mechanisms modifying integrin β protein and activity in mediating monocyte/macrophage adhesion to endothelium remain poorly understood. In this study, we demonstrated that integrin β protein underwent S-nitrosylation in response to nitrosative stress in macrophages. To examine the effect of elevated levels of FFA on the modulation of integrin β expression, we treated the macrophages with a combination of oleic acid and palmitic acid (2:1) and found that FFA activated inducible nitric oxide synthase/nitric oxide and increased the integrin β protein level without altering the mRNA level. FFA promoted integrin β S-nitrosylation via inducible nitric oxide synthase/nitric oxide and prevented its degradation by decreasing binding to E3 ubiquitin ligase c-Cbl. Furthermore, we found that increased integrin αβ heterodimerization resulted in monocyte/macrophage adhesion to endothelium. In conclusion, these results provided novel evidence that FFA-stimulated N--O stabilizes integrin βvia S-nitrosylation, favoring integrin αβ ligation to promote vascular inflammation.