AAV Gene Therapy: Revolutionizing Precision Medicine
In the realm of AAV Gene Therapy, Adeno-Associated Viruses (AAVs) stand out as the frontrunners due to their unique attributes. AAVs have become the go-to viral vectors for gene therapies, thanks to their ability to infiltrate both dividing and non-dividing cells, lack of causing viral illness in humans, and minimal triggering of immune responses that might compromise their therapeutic efficacy.
Recognizing AAVs and Their Flexibility
Adeno-associated viruses, small viruses belonging to the Dependoparvovirus genus in the Parvoviridae family, are pivotal in gene transfer, particularly in the delivery of CRISPR components to the retina. This article unravels the intricacies of utilizing an AAV-based CRISPR/Cas9 system for in vivo genome editing in the retina, highlighting the potential for groundbreaking therapeutic advancements.
The Key Steps in AAV Gene Therapy
Expanding Cell Numbers:
The journey begins with the expansion of the cell population, setting the stage for efficient gene transfer.
Plasmid DNA Addition:
In the bioreactor, plasmid DNA is introduced, paving the way for the integration of therapeutic or marker gene expression cassettes.
Harvest and Filtration:
A critical stage involving the harvesting of modified cells and meticulous filtration to ensure the purity of the AAV vector.
Filtration and Separation:
Further filtration and separation processes refine the AAV vector, enhancing its efficacy for specific clinical applications.
Fill and Finish:
The final step involves filling and finishing the AAV vector, ready for deployment in gene therapy treatments.
AAV Serotypes: Tailoring for Clinical Success
The choice of AAV serotype plays a pivotal role in determining the success of gene therapy. While AAV2 remains widely used, an array of serotypes, including AAV1, AAV5, AAV7, AAV8, and AAV9, offers versatility in targeting different tissues and cell types. AAV8, renowned for its strong tropism to liver cells, showcases superior transduction efficiency in hepatocytes across various models.
AAV Production System: Unraveling the ‘Helper-Free’ Approach
The AAV production system employs a ‘helper-free’ strategy, utilizing three plasmids encoding essential viral and helper genes. These include pHelper, AAV trans-plasmid comprising Rep and Cap genes, and AAV cis-plasmid containing the gene of interest, promoter, and inverse terminal repeats.
Safety Considerations in AAV Gene Therapy
While AAV-mediated gene therapy has shown remarkable promise, it is essential to acknowledge potential side effects. Transient transaminitis, a common side effect, is characterized by a temporary increase in liver enzymes, with no significant liver damage. The precise etiology of AAV-associated hepatitis remains uncertain, with both innate and acquired immune responses implicated.
AAV: A Non-Enveloped Marvel
AAV, with its compact 25-nm size, encapsulates a linear single-stranded DNA genome. Its classification in the genus Dependovirus highlights its dependency on a helper virus (adenovirus or herpesvirus) for productive infection.
The Resurgence of Gene Therapy through AAV
The resurgence in gene therapy efforts is fueled by the versatility and safety of AAVs. As a non-enveloped virus engineered to deliver DNA, AAV has gained significant attention in clinical-stage experimental therapeutic strategies. This article provides an insightful overview of crucial factors to consider when employing AAV as a vector for gene therapy.
In conclusion, Adeno-Associated Viruses have ushered in a new era of precision medicine, offering a safe and effective avenue for gene therapies. As research continues to unravel the full potential of AAV gene therapy, the possibilities for treating a myriad of genetic disorders and diseases appear increasingly promising.
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