Work

31. Modulation Of Mammalian Digit Regeneration With Viral Gene Therapy

Year: 2024

Type: article

Abstract: Purpose: A primary focus of regenerative medicine is to understand the cellular mechanisms governing tissue regeneration across various species. Mammals generally possess a restricted regenerative capacity in comparison to species like zebrafish or axolotls. Notably, all studied mammalian species, including humans, demonstrate the ability to regenerate digit tips following amputation at the level of the distal phalanx. In adult mice, this process involves intramembranous bone regrowth and predominantly scarless healing, rendering them a valuable model for investigating mechanisms of mammalian regeneration. While prior research has aimed to identify genes with pro-regenerative potential, a tissue-specific method for delivering these genes to the digit tip has yet to be established. We asked whether viral constructs can be engineered to direct gene expression in regenerating digits, potentially opening a pathway for gene therapy applications in limb loss and tissue repair. Methods and Results: In this study, we evaluated the expression patterns of multiple adeno-associated virus (AAV) constructs delivering a bioluminescent reporter gene or green fluorescent protein (GFP). Viruses were delivered systemically via retroorbital injection at various time points after mouse digit tip amputation. Bioluminescent and histological imaging revealed that the cc47 capsid variant of AAV9 exhibited broad transduction of the regenerating digit tip. To target gene delivery specifically to the injury site, we administered the cc47 AAV with an injury-specific enhancer element, LEN, upstream of a green fluorescent protein (GFP) reporter gene. Immunofluorescent imaging of the regenerating digits confirmed that the viral construct allowed the successful transduction of GFP in the regenerating digit tip in an injury-specific manner. Conclusion: Here, we show that systemic delivery of AAVs allows for targeted, timely gene expression in the regenerating mouse digit tip. Work is underway to harness the LEN-AAV system for viral delivery of pro-regenerative genes to amputated digits with the aim of enhancing MDT regeneration and ultimately, stimulating regeneration from higher levels of limb amputations.

Source: Plastic & Reconstructive Surgery Global Open

DOI: 10.1097/01.gox.0001015216.21586.e7