Barrier Function of the Extracellular Matrix in AAV Gene Therapy

Area of Science:

• Biomedical Engineering
• Gene Therapy
• Extracellular Matrix Biology

Background:

• The extracellular matrix (ECM) is a critical component of the tissue microenvironment.
• ECM can impede the distribution of adeno-associated virus (AAV) vectors, limiting gene therapy delivery.
• Understanding AAV-ECM interactions is essential to overcome delivery barriers.

Purpose of the Study:

• To investigate how AAV serotype and ECM composition affect AAV transport and gene delivery.
• To elucidate the mechanisms by which ECM influences AAV biodistribution.
• To identify strategies for improving AAV gene therapy efficacy by considering ECM barriers.

Main Methods:

• Fluorescently labeled AAV2, AAV6, and AAV8 vectors were used to visualize diffusion in ECM models.
• Tissue-specific decellularized ECM (dECM) hydrogels (lung, liver, small intestine) were formulated.
• AAV diffusion was quantified using fluorescent microscopy and nanoparticle tracking.
• AAV transduction efficiency was evaluated in dECM-incorporated 2D and 3D spheroid models.

Main Results:

• All tested AAV serotypes exhibited reduced diffusivity in ECM compared to nanoparticles.
• AAV2 showed the least diffusion impairment across different ECM compositions.
• AAV6 and AAV8 diffusion were more significantly affected by ECM presence.
• AAV transduction was substantially reduced in dECM-incorporated 2D and 3D *in vitro* models.

Conclusions:

• AAV binding to the ECM can decrease therapeutic efficacy in target tissues.
• The barrier properties of the ECM must be considered during the development of AAV-based gene therapies.
• Optimizing AAV vector design and delivery strategies to mitigate ECM interactions is necessary.