PTX3 and obesity due to melanocortin 4 receptor deficiency: In obesity-induced atherosclerosis, high-density lipoprotein (HDL) is able to promote high expression levels of PTX3 by activating the PI3K/AKT (phosphatidylinositol-3-kinase/protein kinase-B) pathway, leading to an increase in the expression of APO-1 in vivo [51].