Adeno-Associated Virus-Mediated Gene Therapy in the Mashlool, Atp1a3Mashl/+, Mouse Model of Alternating Hemiplegia of Childhood
Arsen S. Hunanyan, Boris Kantor, Ram S. Puranam, Courtney Elliott, Angela McCall, Justin Dhindsa, Promila Pagadala, Keri Wallace, Jordan Poe, Talha Gunduz, Aravind Asokan, Dwight D. Koeberl, Mai K. ElMallah, and Mohamad A. Mikati
Alternating Hemiplegia of Childhood (AHC) is a devastating autosomal dominant disorder caused by ATP1A3 mutations, resulting in severe hemiplegia and dystonia spells, ataxia, debilitating disabilities, and premature death. Here, we determine the effects of delivering an extra copy of the normal gene in a mouse model carrying the most common mutation causing AHC in humans, the D801N mutation. We used an adeno-associated virus serotype 9 (AAV9) vector expressing the human ATP1A3 gene under the control of a human Synapsin promoter. We first demonstrated that intracerebroventricular (ICV) injection of this vector in wild-type mice on postnatal day 10 (P10) results in increases in ouabain-sensitive ATPase activity and in expression of reporter genes in targeted brain regions. We then tested this vector in mutant mice. Simultaneous intracisterna magna and bilateral ICV injections of this vector at P10 resulted, at P40, in reduction of inducible hemiplegia spells, improvement in balance beam test performance, and prolonged survival of treated mutant mice up to P70. Our study demonstrates, as a proof of concept, that gene therapy can induce favorable effects in a disease caused by a mutation of the gene of a protein that is, at the same time, an ATPase enzyme, a pump, and a signal transduction factor.
March 5, 2019 – Joint message from Cure AHC, AHC Foundation and Hope for Annabel:
To pick an analogy for this second AAV Project update, we would say that it is like preparing for space travel. We have the captain and crew, but before we start the countdown we need to make sure our rocket has a clear target, is thoroughly tested, and is fully loaded with fuel and supplies.
Since June 2018, Cure AHC, AHC Foundation and Hope for Annabel have been collaborating on a gene therapy effort using Adeno Associated Virus (AAV) as a system to deliver functioning ATP1A3 to compensate for the mutated ATP1A3 associated with AHC. This project will require many phases with several steps in each phase to eventually get to a clinical trial. We are just in the first phase of the AAV Project where we are developing a viral vector and testing its effects in mice.
In our last update on January 20th, we shared that the three foundations had funded over $225,000 of preliminary research and development in preparation for the experiments on mice scheduled to start on April 1st. We shared that this next step of mice experiments would cost approximately $500,000.
Our rocket is fueled: Due to the phenomenal fundraising efforts by families, friends and strangers, we are thrilled to share that the 3 foundations have $436,000 in the bank to dedicate to the next steps of the AAV Project! In addition, our international partners from France, Iceland, Ireland, Netherlands, Spain and the United Kingdom have pledged over $110,000 towards the AAV Project. We are absolutely in awe of the support of this AAV Project by the AHC community and beyond!
While we have been able to pool resources to meet and exceed the $500,000 goal for the mouse experiments, please don’t stop your fundraising efforts! The AAV Project is a multi-phased initiative. Our gene therapy project is already attractive to industry and institutions who are offering financial support, and the more we can raise as a community the more we can attract the right institutions and the right capital partners. The goal is to keep our therapy affordable or free for patients and families, and there is much more that we as a community will need to do and fund before we can accomplish that.
Redundancy plans, safety checks, and rocket-supplies: Our therapy is performing very well in initial experiments, but we have concluded that further testing is necessary before we launch our rocket-ship. We are determined to proceed carefully and methodically. Thoroughness is even more important than speed.
There are still two fundamental questions we need to answer before our rocket has “lift-off”: (1) can our rocket go far enough (biodistribution), and (2) is our payload potent enough (viral potency). As a result, we are doing another round of quality-control testing, and we are building the same set of viral vectors using a different production technique as a redundancy plan. To avoid lift-off too early, we need to make sure our therapy will deliver ATP1A3 to the right parts of the brain in exactly the right amounts. We estimate these additional tests will take approximately three months. In addition, the development of the mouse colony for experiments is also seeing some delays. We need the mice to breed quickly to create a large enough colony for our planned tests but breeding mice with AHC is challenging. The upside is that by doing our additional quality control testing, the mice colony will have time to grow as well.
We want to make sure that the families who have embraced this effort are not disheartened. Timeline delays are commonplace for meticulous scientists. We have a rocket-ship that is fully fueled, with a captain and a crew. Take-off is slightly delayed since we have chosen to implement additional tests. We feel an intense responsibility to be excellent stewards of your fundraising efforts to ensure we get the best therapeutic results for our kids.
Families and organizations wanting to support the AAV Project should feel comfortable directing fundraising efforts to one, two or all three of the foundations: Cure AHC, AHC Foundation or Hope for Annabel.
For questions about the AAV Project or specific fundraising efforts, please contact Jeff Wuchich (firstname.lastname@example.org), Lynn Egan (email@example.com) and Simon Frost (firstname.lastname@example.org).
AESHA (the Spanish AHC association) is hosting a Symposium on AHC in Barcelona on February 9th 2019.
The program is very interesting and registration is free
The 8th symposium on ATP1A3 will be held in Reykjavik, Iceland October 3-4th 2019.
President of Iceland will open the symposium and Kari Stefansson CEO of DeCode will present.
It will be a symposium worth joining and we will have research result from many fantastic researchers.