Jan Asad (DANDRITE, Aarhus Institute of Advanced Studies and Department of Biomedicine) and colleagues from Core Centre for Molecular Morphology, Department of Clinical Medicine, and Centre for Stochastic Geometry and Advanced Bioimaging (Aarhus University) have recently publish a paper in Neuroscience Insights.
2020.01.08 | AISHA RAFIQUE
Delivery of recombinant adeno-associated virus serotypes via hindlimb intramuscular injection in mouse model. Figure credit: Aisha Rafique Delivery of recombinant adeno-associated virus serotypes via hindlimb intramuscular injection in mouse model. Figure credit: Aisha Rafique
A micrograph showing eGFP expression in ventral horn motor neurons of a mouse injected with rAAV serotype 2/6 encoding eGFP under the synapsin promoter. Image credit: Jan AsadA micrograph showing eGFP expression in ventral horn motor neurons of a mouse injected with rAAV serotype 2/6 encoding eGFP under the synapsin promoter. Image credit: Jan Asad
Briefly highlight the background of this project/publication?
Recombinant AAV (rAAV) vectors are widely used in neuroscience research for gene transfer and model development. In adult nervous tissue, a common challenge is the efficient delivery of rAAV in select neuroanatomical areas, which is most commonly achieved by direct parenchymal (i.e., intracerebral or intrathecal) injection. Although advantageous in achieving high gene expression at the site of injection, this invasive approach is associated with tissue trauma and concurrent inflammation, which could be confounding factors (e.g., especially in models of chronic neurological diseases), but may also affect transgene expression. Of the commonly used rAAV serotypes, rAAV2/6, 2/8 and 2/9 have been proposed to exhibit retrograde transduction following peripheral routes of delivery. In this report, we provide a side-by-side comparison of these neurotropic rAAV serotypes, and show successful transduction of local nervous structures following a single intramuscular inoculation in the hindlimb of adult wild type mice.
Outline the main findings/results of the publication?
Our data show that the select rAAV serotypes transduce sciatic nerve and groups of neurons in the dorsal root ganglia on the injected side, indicating that that the intramuscular rAAV delivery is useful for achieving gene transfer in local neuroanatomical tracts. We also observed sparse rAAV viral delivery or eGFP transduction in lumbar spinal cord and a noticeable lack thereof in brain. Therefore, further improvements in rAAV design are warranted in order to achieve efficient widespread retrograde transduction following intramuscular and possibly other peripheral routes of delivery. The lack of widespread dissemination of rAAV following i.m delivery may be advantageous in studies aimed at targeting local nerve structures, as for interrogating function of specific genes in models of sensory dysfunction such as neuropathic pain, or for therapeutic gene delivery following nerve injury, and possibly in models of demyelinating diseases.
In terms of this publication, can you articulate on the internal collaboration and working relationship between Biomedicine and Clinical Medicine?
The work was a close collaboration between groups of Prof. Poul Henning Jensen and Associate Professor Christian Vægter at Biomedicine and Prof. Jens Rendal Nyengaard at the department of Clinical Medicine, Aarhus University.
If possible, what is the next step in this project - future perspectives?
We have identified rAAV2/6 as a promising vector for gene delivery or the delivery of genome editing constructs into nerves and spinal cord tissue, following intramuscular inoculation. As our major focus is blocking the propagation of misfolded proteins from peripheral to central nervous system in models of neurodegenerative diseases such as Parkinson's, we will test some mechanistic hypotheses using rAAV mediated delivery of candidate genes or genome editing by CRISPR/Cas9 in cellular and animal models.
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