Abstract P774: Therapeutic Efficacy of Next Generation Anti-miR-141-3p for Ischemic Stroke

Abstract

Background: Stroke and factors modifying stroke responses, such as social isolation, increases miR-141-3p. Hence, inhibiting miR-141-3p can be a promising stroke therapy. Unfortunately, commercially available miR-141-3p inhibitors cannot be used for therapeutic purpose due to several limitations; use of viral or non-viral transfection reagents for cell penetration, in vivo instability of anti-miRs and toxicity of synthetic anti-miRs. Therefore, we explored phosphorothioates (PS) and peptide nucleic acids (PNAs) based anti-miR-141-3p encapsulated in poly (lactide-co-glycolide) (PLGA)-based nanoparticles (NPs) for potential stroke therapy. Methods: PNAs and PS anti-miR 141-3p were synthesized in house using solid phase synthesis and purchased from a commercial vendor, respectively. The anti-miRs were encapsulated in PLGA NP by double emulsion solvent evaporation technique. For in vivo efficacy 8-10 weeks old C57BL/6 male mice were pair-housed (PH) for at least two weeks. After two weeks, a 60-minute right middle cerebral artery occlusion surgery (MCAO) was performed and mice were kept individually. The mice were then randomly assigned to receive NPs of either anti-miR-141-3p PNA or anti-miR-141-3p phosphorothioate (PS) or scrambled control (Sc) through lateral tail vein 4 hrs. after stroke. To measure NPs of PS were conjugated with fluorophore (TAMRA) to measure BBB permeability. The effect of inhibitor treatment was evaluated at 3 days after stroke. Results: The formulated NPs show uniform morphology with a mean dry particle size <120 nm and an average hydrodynamic diameter of 350 nm. The NPs exhibit an average polydispersity index of 0.1-0.2 indicating homogenous particle size distribution. Single dose of anti-miR 141 and (NPs containing 0.05mg/kg i.v of total either PNA or PS) Both the NPs of PNA and PS significantly reduced (P<0.05 vs. Sc) infarct injury and neurological deficit. Anti-miR of PNA and PS reduce 6 and 5-fold respectively of miR-141-3p in the brain tissue. Conclusion: Our NPs are BBB permeable. PNA based anti-miR-141 are more potent the PS based anti-miR Reduced miR-141-3p levels as well as infarct injury by both PS and PNA based anti-miR 141-3p suggest the efficacy of our novel ant-miR -141-3p for the treatment of ischemic stroke.