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Published on: February 26, 2019
Focused ultrasound widely broadens AAV-delivered Cas9 distribution and activity
Emrah Gumusgoz1, Sahba Kasiri1, Ibrahim Youssef2,3,4
1Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
Insights
Focused ultrasound (FUS) significantly enhances gene delivery to the brain via adeno-associated virus (AAV) by temporarily opening the blood-brain barrier (BBB). This approach successfully reduced disease pathology in a mouse model of Lafora disease, offering new hope for treating genetic neurological disorders.
Area of Science:
- Neurology
- Genetics
- Biotechnology
Background:
- Pediatric neurological diseases are often genetic due to limited environmental exposure in childhood.
- Gene therapy and genome editing hold promise for treating these conditions.
- The mature blood-brain barrier (BBB) restricts adeno-associated virus (AAV) delivery to the brain, limiting therapeutic efficacy.
Purpose of the Study:
- To investigate the efficacy of focused ultrasound (FUS) in enhancing AAV-mediated gene delivery across the BBB.
- To assess the therapeutic potential of FUS-guided gene editing in a mouse model of Lafora disease.
Main Methods:
- Focused ultrasound (FUS) was used to transiently open the hippocampal BBB in mice.
- Cas9 gene was delivered intrathecally via AAV9, with FUS enhancing brain-first pass distribution.
- The study utilized a mouse model of Lafora disease, a genetic neuroinflammatory disorder.
Main Results:
- FUS dramatically increased hippocampal Cas9 distribution by approximately 2000-fold.
- FUS-guided gene delivery significantly reduced pathogenic glycogen accumulation.
- A marked reduction in hippocampal inflammation was observed in treated mice.
Conclusions:
- Focused ultrasound (FUS) is a safe and effective method for enhancing AAV-mediated gene delivery across the BBB.
- This approach holds significant potential for broadening gene therapy and genome editing applications in treating brain diseases.
- FUS-mediated gene delivery offers a promising strategy for clearing the pathological basis of neurological disorders.
Abstract:
Because children have little temporal exposure to environment and aging, most pediatric neurological diseases are inherent, i.e. genetic. Since postnatal neurons and astrocytes are mostly non-replicating, gene therapy and genome editing present enormous promise in child neurology. Unlike in other organs, which are highly permissive to adeno-associated viruses (AAV), the mature blood-brain barrier (BBB) greatly limits circulating AAV distribution to the brain. Intrathecal administration improves distribution but to no more than 20% of brain cells. Focused ultrasound (FUS) opens the BBB transiently and safely. In the present work we opened the hippocampal BBB and delivered a Cas9 gene via AAV9 intrathecally. This allowed brain first-pass, and subsequent vascular circulation and re-entry through the opened BBB. The mouse model used was of Lafora disease, a neuroinflammatory disease due to accumulations of misshapen overlong-branched glycogen. Cas9 was targeted to the gene of the glycogen branch-elongating enzyme glycogen synthase. We show that FUS dramatically (2000-fold) improved hippocampal Cas9 distribution and greatly reduced the pathogenic glycogen accumulations and hippocampal inflammation. FUS is in regular clinical use for other indications. Our work shows that it has the potential to vastly broaden gene delivery or editing along with clearance of corresponding pathologic basis of brain disease.
