Ultrasound-guided intrahepatic release of therapeutic nucleic acids for treatment of inflammatory liver disease

• Applicant: Privatdozent Matthias Bartneck, Ph.D.
• Subject Area: Gastroenterology ; Immunology
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 417882771

Drugs based on RNA receive increased attention since the use of mRNA-vaccines. We have recently explored strategies to enhance targeting lipid nanoparticles (LNP) formulated RNA to myeloid immune cells by pretreatment with small molecules. We further identified pro-miR146a-LNP most suitable among various small non-coding nucleic acids (snc-NA) for treating liver inflammation based on macrophage reprogramming. However, off-target accumulations remain a major limitation of LNP and other delivery systems. The opportunity for a regioselective release of nucleic acids would open novel avenues to design snc-NA-based drugs with improved tolerability and specificity. Here, we aim to use a DNA nanoflower-based mechanoresponsive drug delivery system (DDS) for pro-miR146a that can be locally released in the liver upon using clinical ultrasound. The novelty of the DDS is that it does not require microbubbles which can harmful tissues owed to sonoporation.The specific aims are: 1) Generation and characterization the pro-miR146a-DDS:We recently demonstrated applicability of a single component US-responsive DDS that releases its cargo upon US in vitro and in vivo to deliver immunostimulatory single stranded DNA. Here, we aim to generate a two-component DDS for delivery of double stranded pro-miR146a using established methodology. The DDS is based on a DNA backbone that is complementary to each one strand of the pro-miR. 2) Biodistribution and uptake mechanism of the DDS:We aim to study the behavior of the DDS including US in the liver using intravital imaging. This enables to precisely determine the cell types that internalize the DDS and the effects of on these cells. The mechanism that accounts for the rapid liver uptake of the DDS is likely reflected by adsorbed proteins that are recognized by the cells and thus we study these using proteomics. The in vivo precision of the DDS is analyzed by comparing parts of the liver that received sonication compared to unsonicated parts and to other organs. The potential intrahepatic or interorgan immune cell migration is studied by flow cytometry and the molecular effects are analyzed by established transcriptomics and proteomics. 3) US-guided release of pro-miR146a for treatment of inflammatory liver disease:The influx and efflux of leukocytes is also an important factor for inflammatory liver disease. Hence, intravital imaging is also done to understand the impact on the hepatic immune cell influx before, during, and after the localized treatment. The ultimate aim is to use the novel US-responsive pro-miR-146a DDS in the established model of autoimmune hepatitis induced by Concanavalin A. The application of the DDS to locally release snc-NA for therapeutic purposes represents a groundbreaking novel strategy that is applicable to treat various types of internal inflammatory disease that would profit from an organ-specific treatment with reduced side effects.

• DFG Programme: Research Grants