Therapeutic Ultrasound and Bubble Liposomes-Induced Local Delivery for Bdnf Mrna with the Huntington’S Disease Protein in Transgenic Mouse Brain as a Multifunctional Platform

Developments of small-scale functional and molecular imaging-enhanced approaches are able to visualize the neurite of the cells in the brain in order to evaluate the network and mechanism involved in CNS disease. Microbubbles have shown potential as intracranial ultrasound contrast agents while nucleic acid-loaded microbubbles are increasingly investigated for ultrasound-triggered theranostic platform. In this three-year project, the object is to visualize neuronal transprot in the HD transgenic brain in order to evaluate the network involved in basic neurodegenerative functions. We are able to identify single nerve cells in the brain by using confocal microscopy and in vivo imaging system (IVIS) after performing ultrasound-mediated bubble-liposome destruction. Studies have also implicated that reduced levels of brain-derived neurotrophic factor (BDNF) is the reason to cause HD pathogenesis. Huntington’s disease (HD) is a dominantly inherited neurodegenerative disorder caused by a CAG trinucleotide repeat expansion in the huntingtin (Htt) gene, which results in a protein with an abnormally long polyglutamine sequence. Mutant huntingtin (mHtt) protein was previously reported to decrease BDNF gene transcription and axonal transport of BDNF. A platform can serve as theranostics by using ultrasound sonication and BDNF mRNA-loaded bubble-liposomes transfer to the Huntington’s disease protein in HD brain for small-scale functional imaging. Enhanced mHtt co-localizes with mRNAs and neuronal granules is hypothesized that it might play a role in post-transcriptional transport/targeting of mRNA for BDNF, thus contributing to neurotrophic support and neuron survival. In addition, this ultra-localized delivery technology of genes/drugs into single cell may help in understanding the neural network and mechanism of the function of the HD brain. The major jobs in this research project are listed as following:1. BDNF mRNA will be produced by in vitro transcription from BDNF genes. Analysis of BDNF mRNA-loaded bubble-liposome stability and expression for noninvasive ultrasound delivery system;2. Expression of BDNF mRNA-loaded bubble-liposomes will be conducted in vitro to in vivo associated with mHtt and components of neuronal RNA granules in cultured neurons and sections of the HD transgenic mouse after ultrasound-BBB system;3. Investigation of BDNF gene expression for stimulating CNS neuronal maturation, survival and neural plasticity factors in HD transgenic mice. This is a three-year research project. For the first year (2018/8-2019/7), we will focus on mRNA transcription from BDNF genes and prepare (GFP-tagged and Luc-tagged) BDNF mRNA bubble-lipsomes for US-BBB opening. For the second year (2019/8-2020/7), the major jobs will be conducted imaging experiments in neurons to demonstrate the co-localization of mHtt and expressed BDNF mRNA from in vitro to in vivo after performing US-enhanced nucleic acid delivery. For the third year (2020/8-2021/7), to investigate the downstream pathways of BDNF mRNA with mHtt, Ago 2, CPEB and dynein in the HD brain neurons.

Project ID:PB10707-0233
External Project ID:MOST107-2221-E182-022