Solid tissues can be manipulated ex vivo and used as vehicles for gene therapy

Area of Science:

• Biotechnology
• Tissue Engineering
• Gene Therapy

Background:

• Organ fragments, termed micro-organs (MOs), can be cultured ex vivo while retaining tissue-specific gene expression.
• This methodology allows for the engineering of MOs through gene transfer.

Purpose of the Study:

• To engineer micro-organs (MOs) ex vivo using gene transfer.
• To evaluate the efficacy of different viral vectors for gene delivery into MOs.
• To assess the in vivo behavior and therapeutic potential of engineered MOs.

Main Methods:

• Micro-organs (MOs) from spleen, lung, colon, and skin were cultured.
• MOs were infected with herpes simplex type-1, adenovirus, vaccinia virus, and murine leukemia virus (MuLV) carrying the beta-galactosidase reporter gene.
• Optimization of viral vector infection and assessment of gene expression in vitro and after implantation into syngeneic hosts.

Main Results:

• All tested viral vectors successfully infected MOs, with adenovirus showing higher efficiency.
• Murine leukemia virus (MuLV) achieved high gene expression levels (>15% positive cells) after optimization, comparable to adenovirus.
• Engineered MOs remained localized, became vascularized, and expressed the transduced gene for months after implantation in vivo.

Conclusions:

• The engineered MO system facilitates the study of virus-tissue interactions both ex vivo and in vivo.
• This approach presents a novel platform for ex vivo gene therapy.
• Engineered MOs could function as autologous biological pumps for sustained in vivo secretion of clinically important gene products.