Abstract 198: Polymeric Transfection Is Superior to Traditional Transfection Methods in Targeting the Cellular Processes of Intimal Hyperplasia
OBJECTIVE: We have previously demonstrated that targeted MT1-MMP (MT1) silencing, via pharmaceutical transfection, inhibits the cellular processes of intimal hyperplasia (IH) in vitro. Manipulation of MT1 in vivo should be examined for the prevention of IH, but traditional methods of genetic delivery are poorly translatable in vivo. Biodegradable polymers have shown promise in their ability to safely deliver genetic material in early feasibility studies using stem cells. Our goal is to establish polymeric transfection as an effective method for gene therapy in differentiated vascular cells and as a translatable option for therapeutic gene modulation in the prevention of IH. Here we compared polymeric transfection and traditional pharmaceutical transfection in their efficiency in MT1 silencing and their downstream effectiveness in the inhibition vascular smooth muscle cell (VSMC) migration and proliferation.
METHODS: VSMCs were transfected with MT1 or negative control (NC) siRNA using DharmaFECT2 complexes (Dharm) or poly(β-amino ester) polymer bioconjugates (StemFECT; Stem).
RESULTS: Stem was significantly more effective than Dharm in silencing MT1 (% expression vs. NC; Stem=40±3*; Dharm= 58±6%; n=4-7; *P<0.05). Zymography revealed that silencing of MT1 decreased MMP-2 activity similarly in both methods. Silencing of MT1 via Stem decreased migration to 59±6% vs. NC (n=7; P<0.05), while silencing via Dharm only decreased migration to 88±6% vs. NC (n=3). Likewise, silencing of MT1 via Stem inhibited basal and serum-stimulated proliferation to 89±3% and 97±6% vs. NC respectively (FBS=162±6%; n=4-6; P<0.05), while silencing via Dharm did not significantly inhibit basal or serum-stimulated proliferation.
CONCLUSION: Evidence here demonstrates 1) VSMCs can be genetically altered via polymeric transfection in a manner superior to traditional pharmaceutical transfection and 2) silencing MT1 via polymeric transfection is equally effective in decreasing MMP enzymatic activity and more effective in inhibiting the end cellular responses of IH development in vitro. Polymeric transfection has potential for in vivo delivery of molecular inhibitors of MT1 and others aimed at targeted genetic therapy for vascular disease.
- © 2012 by American Heart Association, Inc.