Our PhD Students, Natalia Hernández and Marcos Sánchez, at the Gene and Cell Teraphy Congress and the Biennial Chemistry Meeting
Natalia Hernández Bellido: “Non-viral delivery of microRNA therapies for cardiac dysfunction using DNA nanostructures”
Cardiac microRNAs (miRNAs) are dysregulated in cardiac disease and aging. Thanks to their pleiotropic effects, they are spotlighted as therapeutic targets to treat cardiac conditions. Nanotechnology enables targeted delivery of miRNA therapies, avoiding their low stability and potential off-target effects. Particularly, DNA nanostructures (DNS) for miRNA therapies have not yet been applied to cardiac disease. Our group has identified MIR24-2 upregulated with age in human left ventricle and miR24-2-5p to interact with genes essential in cardiac function, such as SERCA2, which is also downregulated in heart failure.
The main goal of this study is to demonstrate the capacity of DNS to deliver anti-miRNA therapies in human cardiomyocytes.
Different versions of DNS were designed and generated by self-assembly of DNA strands containing anti-miR24-2-5p capture segments. Their physicochemical and structural characterization showed optimal thermal stability at physiological temperature, proper stability in serum and specific disassembly in the presence of miR24-2-5p. Biological characterization of DNS in vitro in Hek293 cells demonstrated high uptake levels with partial degradation after 48h. However, internalization in human induced pluripotent stem cells (iPSC)-derived cardiomyocytes (iCM) was remarkably lower. DNS demonstrated in vitro biocompatibility in both, Hek293 and in iCM.
To conclude, our biocompatible anti-miR-loaded DNS effectively capture miR-24-2-5p in vitro and internalized in iCM, indicating their suitability to carry miRNA therapies to iCM in vitro, although with lower efficiency than in Hek293 cells. Therefore, future efforts will focus on DNS functionalization with ligands that promote their efficient and specific uptake by primary cardiac cells.
Marcos Sánchez Barat: “Development of customised DNA-based nanostructures to treat heart disease by gene therapy”
Cardiovascular diseases are the main cause of death in Western countries. Nearly 50% of these deaths are due to ischaemic heart disease, including myocardial infarction. When not lethal, myocardial infarction leads to myocardial remodelling that can progress to heart failure.
Despite the great impact that this entails, there is no specific therapy for myocardial regeneration after myocardial infarction that prevents the maladaptive remodelling and progress towards heart failure.  Therefore, the objective of our study is the development of a novel nanotherapy based on the encapsulation of microRNAs in DNA nanostructures (DNS) capable of inducing myocardial regeneration.
Specifically, miR-199a-3p will be used, which has shown to induce cardiac regeneration through its pro-proliferative action on cardiomyocytes in studies carried out in mice, rats and pigs.
Here we generate DNS built by the self-assembly of DNA strands designed with precise sequences to load large amounts of the targeted miR-199a-3p through Watson-Crick-Franklin base-pairing interactions. DNS have been characterized by gel electrophoresis (GE) and dynamic light scattering. In vitro release of the loaded miR produced by RNAse H has been investigated by GE. Also, we have created a functional assay based on luciferase reporter activity and miR sponges to specifically measure the activity of the miR intracellularly. This proves the interaction of the miR-199a-3p with its target gene sequence once released from the DNS by the intracellular RNAse H. In conclusion, our results show the formation of a DNS capable of carrying and releasing a therapeutic miR through the processing of the cell's own machinery and the functionality of this miR after being released from the DNA by being able to bind to its target.