MMP9 and atherosclerosis: Similarly, under TNF-α, high glucose, or lipopolysaccharide (LPS) stimulation, the overexpression of the orphan C-family G protein-coupled receptor 5B (GPRC5B) phosphorylates ERK1/2, activates NF-κB, and enhances MMP-9 expression in the vascular wall, contributing to inflammation and atherosclerosis [118].