Abstract 14539: Multifunctional Nanoparticles Targeting Endothelial Nf-κB Modulates Inflammation In Experimental Atherosclerosis
The development of atherosclerosis is mediated in part by abnormal activation of the NF-κB signaling pathway leading to the focal expression of inflammatory molecules such as VCAM-1 in endothelium. Moreover, significant crosstalk occurs between endothelium and deeper plaque constituents that drives the inflammatory process. We have designed a multifunctional nanoscale delivery system for targeted anti-inflammatory therapy that comprises: 1) perfluorocarbon nanoparticle (PFC NP), 2) a VCAM 1 targeting ligand, and 3) a NBD (Nemo Binding Domain) peptide that downregulates NF-κB signaling.
Methods and Results:We first validated the action of the NPs on activated mouse 2F2B endothelial cells in vitro. After 5 hours incubations with this targeted therapeutic NP, P65 nuclear translocation and its Ser-468 phosphorylation were inhibited by 40% and 100%, as shown by transcription factor assay and fast activated cell-based ELISA, respectively. By ELISA and immunofluorescence, the expression of NF-κB dependent genes, IL-6 and VCAM1, were shown to be significantly reduced after NP treatment. For in vivo validation of efficacy against NF-κB, ApoE-/- mice on high fat diet for 16 weeks received either saline, NBD loaded NP, or VCAM1 targeted NBD loaded NP via intravenous injection every other day for 2 weeks. Age matched ApoE-/- mice on normal chow served as controls. Treatment was evaluated by immunohistochemistry and RT2-PCR showing that the targeted therapeutic NP reduced degradation of IκB, but did not affect steady state NF-κB mRNA levels, which confirms inhibition of NF-κB activation by promoting the known inhibitory action of IκB. Importantly, the therapy reduces but not obliterates NF-κB activation. Allowing persistence of physiological levels to participate in important physiological cell functions.
Conclusions: A targeted anti-inflammatory NP addressing excessive NF-κB activation in plaque inflammation could serve as a useful adjunct to provide metered responses in atherosclerotic endothelium to limit expression of effector molecules such as VCAM-1. The use of VCAM-1 as the target for cells expressing excessive NF-κB, which drives VCAM 1 expression, is expected to provide specificity for antagonizing pathological inflammatory processes.
- © 2012 by American Heart Association, Inc.