Sprecher
Beschreibung
Alzheimer’s disease is one of the most prevalent cognitive disorders, affecting approximately 35 million people worldwide. This condition is partly driven by chronic neuroinflammation, which leads to progressive neuronal degradation. A key factor in this inflammatory response is the uncontrolled release of cytokines, signaling proteins, extracellular DNA, and notably, microRNAs (miRNAs) which activates microglia, shifting them from a resting phenotype to a pro-inflammatory phenotype.
In drug delivery, due to poor bioavailability or limited stability, certain advanced therapies often require a delivery system. Among them, framework nucleic acids (FNA) have emerged as precise, programmable, biocompatible, biodegradable, self-assembling, and non-immunogenic systems that are spontaneously taken up by cells. DNAzymes, which are catalytic DNA sequences capable of hydrolyzing RNA, can be engineered to selectively bind and cleave target RNA sequences. In this thesis project, we aim to develop a tetrahedron-shaped DNA nanostructure (TET) incorporating a DNAzyme targeting a pro-inflammatory miRNA implicated in neuroinflammation.
Size and shape are the most important factors regarding the internalization of the FNA. Endocytic pathways include mainly clathrin-mediated, caveolin-mediated and phagocytosis, the latter being restricted to macrophages. As our model is phagocytosis-competent cell (microglia, N9), we are also interested to compare the internalization of the TET with the internalization of a bigger nanostructure made by origami. Moreover, we functionalize TET with aptamer allowing to specifically targeting activated microglia, we are interested to compare the difference of uptake by the resting and activated macrophages.
Both by fluorescence microscopy and polymerase chain reaction (PCR), we observed an uptake of TET into the cells around 1000 structures each. Additionally, PCR and western blot analysis revealed a decrease in the level of miR-34a in activated microglia treated with TET and a decrease of the abundance of inflammation markers (iNOS) respectively. These promising results suggest that TET could enhance therapies against neurodegenerative diseases.
