Gene transfer properties and structural modeling of human stem cell-derived AAV

Area of Science:

• Gene therapy
• Virology
• Hematopoietic stem cell biology

Background:

• Adeno-associated virus (AAV) vectors are widely used for in vivo gene delivery.
• Previous studies suggested the presence of AAV in human bone marrow.

Purpose of the Study:

• To investigate the presence of natural AAV in CD34(+) hematopoietic stem cells (HSCs).
• To evaluate the potential of novel AAV variants for HSC gene transfer.

Main Methods:

• Isolation and characterization of AAV from human CD34(+) peripheral blood stem cells.
• Generation of gene transfer vectors from novel AAV variants.
• Assessment of gene transfer efficiency and long-term engraftment in human HSCs and xenograft models.

Main Results:

• Novel AAV variants, belonging to AAV Clade F, were identified in healthy CD34(+) HSCs.
• Vectors derived from these AAVs demonstrated superior gene transfer and stable expression in human HSCs compared to other serotypes.
• Transduced HSCs engrafted in vivo, producing differentiated transgene-expressing progeny and persisting long-term, indicating transduction of primitive progenitors.

Conclusions:

• AAVHSCs represent a new class of genetic vectors with significant potential for HSC genome manipulation.
• Identification of capsid components crucial for HSC transduction was achieved through structure-function correlation.
• These findings pave the way for advanced gene therapy strategies targeting HSCs.