Thesis Defense: Sarah Antilla

Title

Improving Cardiac Delivery of Antisense Oligonucleotides with Peptidomimetic Targeting Agents

Abstract

MicroRNAs (miRNAs) are implicated in the onset and progression of a variety of diseases. Modulating the expression of specific miRNAs is a possible option for therapeutic intervention. A promising strategy is the use of antisense oligonucleotides (ASOs) to inhibit miRNAs. Targeting ASOs to specific tissues can potentially lower the dosage and improve clinical outcomes by alleviating systemic toxicity. We leverage here automated peptide nucleic acid (PNA) synthesis technology to manufacture an anti-miRNA oligonucleotide (antagomir) covalently attached to a 12-mer peptide that binds to transferrin receptor 1 (TfR1). Our PNA-peptide conjugate is active in cells and animals, effectively inhibiting the expression of miRNA-21 both in cultured mouse cardiomyocytes and different mouse organs (heart, liver, kidney, lung, and spleen), while remaining well-tolerated in animals up to the highest tested dose of 30 mg/kg. Conjugating the targeting ligand to the PNA antagomir significantly improved inhibition of miRNA-21 in the heart by over 50% relative to the PNA alone. We also observe a tenfold stronger binding interaction between the dimerized peptide and TfR1 relative to the peptide monomer. A conjugate of the peptide dimer and anti-miRNA-21 PNA at 5 mg/kg exhibits comparable miRNA inhibition in cardiac tissue in vivo to 30 mg/kg monomer conjugate. Given the modulation of biodistribution observed with our PNA-peptide conjugate, we anticipate this antagomir platform to serve as a starting point for pre-clinical development studies.

Thesis Advisor

Bradley Pentelute: Professor of Chemistry, MIT