The polarity protein Scrib limits atherosclerosis development in mice

Atherosclerosis remains a leading cause of mortality worldwide. While endothelial dysfunction is a known contributor, the role of polarity proteins in vascular disease is not well understood. Prior research has shown that Scrib maintains epithelial polarity and endothelial function. However, whether Scrib influences atherosclerosis progression was unclear. This gap motivated investigators to explore Scrib's potential anti-atherosclerotic effects. No prior work had resolved how Scrib might regulate endothelial behavior in disease contexts. Earlier studies suggested Scrib supports endothelial migration and phenotype maintenance. This paper's contribution is to test if Scrib deletion alters atherosclerosis in mice. The study addresses a specific uncertainty about Scrib's role in vascular disease. It builds on prior findings about Scrib's function in endothelial cells.

The aim was to determine if Scrib has anti-atherosclerotic functions in mice. The specific problem was to assess whether Scrib deletion increases atherosclerosis severity. Investigators proposed that Scrib might regulate vascular health through endothelial mechanisms. The motivation was based on prior evidence that Scrib supports endothelial function. The study tested if Scrib knockout mice develop more severe atherosclerosis. The question was whether Scrib maintains endothelial integrity during disease. The researchers proposed that Scrib might regulate vascular permeability and relaxation. The goal was to link Scrib's role in polarity to atherosclerosis progression.

The study used a genetic approach with tamoxifen-induced Scrib knockout mice. These were crossed with ApoE-/- mice to model atherosclerosis. Mice were fed a high-fat diet to induce disease. Partial carotid artery ligation was used to accelerate plaque formation. Endothelial relaxation and AKT phosphorylation were measured in knockout mice. Vascular permeability and leucocyte extravasation were assessed in vivo. Primary carotid endothelial cells were used for Scrib immune pull down and mass spectrometry. siRNA was used to down-regulate Scrib or Arhgef7 in human umbilical vein endothelial cells.

Scrib deletion increased atherosclerosis in both models tested. Endothelium-dependent relaxation was reduced in knockout mice. AKT phosphorylation was also reduced after Scrib deletion. Vascular permeability increased in mice lacking Scrib. Leucocyte extravasation was elevated in Scrib knockout animals. Mass spectrometry identified Arhgef7 as a binding partner of Scrib. siRNA knockdown of Scrib or Arhgef7 reduced endothelial barrier function. Gene expression analysis showed decreased endothelial signature genes in Scrib-deficient mice.

The authors propose that Scrib has anti-atherosclerotic functions in mice. They suggest that Scrib maintains a quiescent endothelial phenotype. Loss of Scrib is linked to increased vascular permeability and relaxation deficits. The findings indicate that Scrib regulates endothelial barrier function. Scrib knockout is associated with endothelial dedifferentiation. The study supports a role for Scrib in preventing atherosclerosis progression. The researchers propose that Scrib interacts with Arhgef7 to regulate endothelial function. The conclusions are based on genetic models and functional assays in mice.