July 19, 2016
A model depicting the concept of gene therapy.
The
ability to switch disease-causing genes on and off remains a dream for many
physicians, research scientists and patients. Research teams from across the
world are busy turning this dream into a reality, incuding a team of
researchers from Charité - Universitätsmedizin Berlin and the Max Planck
Institute for Medical Research in Heidelberg. Led by Dr. Mazahir T. Hasan, and
working under the auspices of the NeuroCure Cluster of Excellence, the team has
successfully programmed a virus to transport the necessary genetic material to
affected tissue and nerve cells inside the body. A report on their new
virus-based method, which delivers instructions to the host genome without
becoming part of it, has been published in the journal Molecular Therapy
Nucleic Acids.
From
cancer to Alzheimer's disease, many life-threatening diseases can only be
treated using drug-based treatment options, if at all. Many of these treatments
are non-specific in nature, or even ineffective. In some cases, the undesirable
side-effects may even outweigh the desirable ones. This is because
indiscriminate treatments damage healthy cells, impairing their ability to
communicate with other cells; as a result, it is hoped that genetically
produced and modified mediators will be able to selectively target diseased
cells, and improve the way treatment is delivered. "In the laboratory, we
use attenuated, i.e. non-replicating,viruses that are known as recombinant
adeno-associated viruses (rAAV). We use them to transport genetically encoded
material into live organisms affected by disease," explains Dr. Hasan.
"This approach opens up a whole range of options which, in the future, may
allow us to treat and heal various diseases."
By
successfully completing the initial step of testing this new method using an
animal model, the researchers have laid the groundwork for future genetic
treatments for use in humans. Before these can be used, however, they will need
to be tested to ensure their safety. It is already known that rAAVs can
transport genetically encoded material into any type of cell and tissue,
including the brain, and that, once inside the cells, they are capable of
repeatedly switching gene therapy
applications on and off again. This on/off switch is controlled chemically, via
either food intake or drinking water: "The fact that gene function can be
switched on and off in this manner is of particular value, and renders the
method a perfect candidate for use in controlled gene therapy," emphasizes
Dr. Hasan
The
fact that rAAV-infected cells do not trigger any form of measurable immune
response and that their genetic material remains completely intact represents
an additional benefit. While this does not mean that future gene therapy
applications are guaranteed to be successful, the researchers are full of
confidence for the future. "We are still at the laboratory stage,"
says Dr. Hasan, adding: "Once additional safety options are in place, this
development could spearhead innovation, heralding in a time when the transfer
of genetically encoded material will be used to heal severe diseases, including
neurological ones such as Parkinson's disease, Alzheimer's disease and
epilepsy."
More
information: Godwin K Dogbevia et al, Flexible, AAV-equipped Genetic
Modules for Inducible Control of Gene Expression in Mammalian Brain, Molecular
Therapy—Nucleic Acids (2016).
http://medicalxpress.com/news/2016-07-path-gene-therapy-virus-molecular-level.html
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