Expression Cassette Design and Regulation of Transgene Expression

Adeno-associated viral vector targeted evolution for neurofibromatosis gene delivery

Neurofibromatosis type 1 (NF1) is an inherited genetic disease resulting from pathogenic mutations in NF1 that drive tumor formation along peripheral nerves, leading to many functional consequences. Tumor removal or treatment often results in regrowth and/or nerve damage. Addressing NF1 pathogenic variations at the cellular level through gene therapy holds great potential for long-term treatment of patients with NF1. Adeno-associated viruses (AAVs) are broadly used gene delivery vehicles for gene therapies because of their low pathogenicity, ability to transduce nondividing cells, and potential for long-term gene expression. This article explores the landscape of AAV-mediated gene delivery strategies for NF1, discusses the challenges of efficient delivery to relevant cell types, and highlights the progress in vector design strategies.

Gene Therapy in Orthopaedics: Progress and Challenges in Pre-Clinical Development and Translation

In orthopaedics, gene-based treatment approaches are being investigated for an array of common -yet medically challenging- pathologic conditions of the skeletal connective tissues and structures (bone, cartilage, ligament, tendon, joints, intervertebral discs etc.). As the skeletal system protects the vital organs and provides weight-bearing structural support, the various tissues are principally composed of dense extracellular matrix (ECM), often with minimal cellularity and vasculature. Due to their functional roles, composition, and distribution throughout the body the skeletal tissues are prone to traumatic injury, and/or structural failure from chronic inflammation and matrix degradation. Due to a mixture of environment and endogenous factors repair processes are often slow and fail to restore the native quality of the ECM and its function. In other cases, large-scale lesions from severe trauma or tumor surgery, exceed the body’s healing and regenerative capacity. Although a wide range of exogenous gene products (proteins and RNAs) have the potential to enhance tissue repair/regeneration and inhibit degenerative disease their clinical use is hindered by the absence of practical methods for safe, effective delivery. Cumulatively, a large body of evidence demonstrates the capacity to transfer coding sequences for biologic agents to cells in the skeletal tissues to achieve prolonged delivery at functional levels to augment local repair or inhibit pathologic processes. With an eye toward clinical translation, we discuss the research progress in the primary injury and disease targets in orthopaedic gene therapy. Technical considerations important to the exploration and pre-clinical development are presented, with an emphasis on vector technologies and delivery strategies whose capacity to generate and sustain functional transgene expression in vivo is well-established.