In vivo-directed evolution has been successfully used to identify novel AAV variants that preferentially transduce the retinal cells of the eye, as well as other cell populations, including those in the CNS [50, 52, 53].
How does AAV infect cells?
When AAV infects a cell alone, its gene expression is repressed (AAV does not replicate), and its genome is incorporated into the host genome (into human chromosome 19). In rare cases, lysis can occur without a helper virus, but usually AAV can not replicate and kill a cell on its own.
What is the AAV receptor?
The recently identified AAV receptor (AAVR) is a key host receptor for multiple serotypes, including the most studied serotype, AAV2. AAVR binds directly to AAV2 particles and is rate limiting for viral transduction.
Can AAV cross blood brain barrier?
The discovery that Adeno-associated virus (AAV) serotype 9 can cross the blood-brain barrier (BBB) when administered systemically delivering genes into the brain and spinal cord has been an important leap forward in this direction.
What are AAV injections?
Adeno-associated virus (AAV) vector-mediated transfer of a normal cDNA can correct the metabolic defects at the site of injection, but treatment of the entire brain requires widespread delivery of the normal gene and/or protein. Current methods require multiple injections for widespread distribution.
How does an AAV work?
How does AAV work? Simply put, AAV is transformed from a naturally occurring virus into a delivery mechanism for gene therapy. The viral DNA is replaced with new DNA, and it becomes a precisely coded vector and is no longer considered a virus, as most of the viral components have been replaced.
What is an AAV capsid?
The protein shell (capsid) of Adeno-associated viruses (AAV) are presently the most promising delivery vehicles for various in vivo gene therapies. AAVs are non-pathogenic and, through past engineering efforts, have become safe due to their inability to integrate into and damage the genome of target cells.
Does AAV cause disease?
Though AAV is not known to cause disease in humans, precautions must be taken due to the possibility of insertional mutagenesis. In addition, helper viruses used to trigger AAV replication may cause disease. Numerous serotypes of adeno-associated virus with different cell tropisms have been isolated.
How does adeno associated virus work?
How long does AAV last?
and Xiao et al. showed that an AAV vector would continue to express its transgene for 6–12 months in vivo. Subsequently, expression from an AAV vector in a canine eye persisted unabated for up to 12 years (William Hauswirth, unpublished), and similar results have been reported for muscle and brain transductions.
Is astrocyte a potential target for adeno-associated virus gene therapy?
Adeno-associated virus (AAV)-mediated gene delivery has been proposed to be an essential tool of gene therapy for various brain diseases. Among several cell types in the brain, astrocyte has become a promising therapeutic target for brain diseases, as more and more contribution of astrocytes in pathophysiology has been revealed.
Are specific AAV serotypes required to deliver transgenes of interest to astrocytes?
AAVDJ8 displayed more tropism in astrocytes compared to AAV9 in the SN region. We conclude that ICV injection results in lasting expression of virally encoded transgene when using AAV vectors and that specific AAV serotypes are required to selectively deliver transgenes of interest to different brain regions in both astrocytes and neurons.
Can an AAV vector target astrocytes in spinal cord injury?
Considering the role of astrocytes in the on-going secondary damage in spinal cord injury (SCI), an AAV vector that targets astrocytes could show benefit as a potential treatment.
Do AAV5 and AAV9 have the greatest propensity astrocytes in the CNS?
The serotypes AAV5 and AAV9 were selected for investigation in this study because in previous studies they have been characterised to exhibit the greatest propensity astrocytes in various CNS regions including spinal cord by various constitutive promoters or glial-specific promoters [ 6, 7, 8, 9, 10, 11 ].
