Quintuple-target RNAi: hitting five targets is better than just one
Vascular endothelial cells express five adhesion molecules to recruit leukocytes from the blood stream: E- and P-selectin, ICAM-1 and -2, and VCAM-1. In atherosclerosis, activated endothelial cells express high levels of these signals, thus expanding the number of neutrophils and monocytes that migrate from blood into a growing plaque. After myocardial infarction, the adhesion molecule expression increases even further due to higher autonomic nervous activity. A collaborating team of groups at MIT and MGH now used a new class of nanoparticles with high avidity to endothelial cells to decrease endothelial cell adhesion molecule expression. The polymeric nanoparticles made of low-molecular-weight polyamines and lipids were loaded with 5 distinct siRNAs silencing the expression of all adhesion molecules. Multiple gene silencing was enabled by exquisite silencing efficiency after nanoparticle delivery. Hitting five targets at once, the therapy reduced recruitment of leukocytes to atherosclerotic plaques in mice, dampening vascular wall inflammation and making plaques smaller. Furthermore, RNAi decreased migration of leukocytes into infarcted myocardium, improving the recovery after ischemia. Such a strategy may help to prevent reinfarction and heart failure in high-risk patients with acute MI.
The MGH Center for Systems Biology (CSB) was established as one of the five thematic interdisciplinary Centers at MGH. It is home to over 200 researchers in 12 PI groups. The mission of the Center is to analyze at a systems level how biological molecules, proteins and cells interact in both healthy and diseased states.
Through a multidisciplinary approach that combines clinical insight with powerful technologies, CSB faculty pursue systems-level research that is at once fundamental, and yet immediately linked to the diagnosis and treatment of human disease. While these approaches are generalizable to many diseases, the Center has particular strengths in complex human conditions such as cancer, cardiovascular disease, diabetes, autoimmune disease, and renal disease. This goal is enabled by particular faculty expertise in genomics, chemical biology, physiology, bioimaging, and nanotechnology.