Yin-Yang 1/Neural Precursor Cell-Expressed Developmentally Downregulated 4-Like Axis Suppresses Mer Tyrosine...

Atherosclerosis is considered as a major contributor for cardiovascular disease with high morbidity and mortality globally. However, the cross-talk between efferocytosis and inflammation in atherosclerosis remains elusive.

ApoE (apolipoprotein E)^-/- mice and oxidized low-density lipoprotein-induced in vitro atherosclerosis models were established. The histological changes and lipid accumulation in arteries were evaluated by hematoxylin and eosin and Oil red O staining. Efferocytosis was monitored by in situ or in vitro efferocytosis assay. Western blot, immunohistochemistry, and ELISA were employed to detect the expression of target molecules and pyroptosis-related molecules. Caspase-1/propidium iodide was used to assess cell pyroptosis in macrophages. The interaction between NEDD4L (neural precursor cell-expressed developmentally downregulated 4-like) and MerTK (Mer tyrosine kinase), as well as the ubiquitination of MerTK was examined by co-immunoprecipitation. Additionally, the interaction between YY1 (Yin Yang 1) and NEDD4L promoter was detected by chromatin immunoprecipitation and luciferase assays.

YY1 and NEDD4L were upregulated, but MerTK was downregulated in the arteries of ApoE^-/- mice. The addition of apoptotic cells deteriorated atherosclerosis through activating NLRP3 (nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3)-mediated inflammation and pyroptosis. Silencing of MerTK exacerbated atherosclerosis via suppressing efferocytosis and activating NLRP3-mediated inflammation and pyroptosis, whereas NEDD4L knockdown or YY1 silencing exerted opposite effects in the in vitro atherosclerosis model. Mechanistically, NEDD4L was identified as an E3 ligase responsible for MerTK degradation, and YY1 served as a transcriptional activator of NEDD4L.

Our findings demonstrated that YY1 positively regulated NEDD4L to modulate MerTK-mediated efferocytosis and activate NLRP3-mediated inflammation and pyroptosis, thus exacerbating atherosclerosis.