Delivery and imaging of miRNAs by multifunctional carbon nanotubes as innovative therapeutic tool for pediatric pulmonary hypertension

Despite the advent of efficacious therapies for pediatric pulmonary hypertension (PH), prevention remains a priority. There are few therapeutic options currently available for children with PH. The advent of nanotechnology provide new opportunity for therapeutic strategy. Carbon nanotubes (CNTs) are emerging as promising systems for transfection of drugs, small molecules and, recently, have been widely studied for the delivery of nucleic acids and small interfering RNAs (siRNAs). In this dissertation, I report the preparation of delivery systems based on carbon nanotubes (CNTs) to deliver microRNAs (miRNAs) in order to regulate the angiogenesis in pulmonary hypertension. These systems have been obtained through the functionalization of CNTs with two polymers: polyethyleneimine (PEI) or polyamidoamine dendrimer (PAMAM), followed by conjugation of microRNA-503 oligonucleotides (a recognized regulator of angiogenesis). The in vitro and in vivo results demonstrated a low toxicity of these compounds and the efficient delivery of miR-503 in endothelial cells. The polymers-CNTs complexed with miR-503 have a functional role in endothelial cells, regulating target genes. Their effects have been demonstrated in a mouse model of angiogenesis (cell proliferation and angiogenic sprouting). In a first method we used an excess of polymer while in a second method we improved the protocol preparation using a reduced amount of polymer. Finally, we developed a multifunctional vector consisting in CNTs functionalized with PAMAM, an oligonucleotide mimicking miR-503 and a near-IR probe (IR-820). CNTs have been injected in the lung of mice, and followed for 24 hours. No relevant inflammation or damage was detected in lung tissue.