Assessing the delivery of human glucagon-like peptide (GLP)-1 using an adeno-associated virus-serotype 9 (AAV9) vector

Abstract

Glucagon-like peptide (GLP-1) is an incretin hormone secreted from intestinal cells in response to food. In the central nervous system, GLP-1 is produced from neurons, and GLP-1 receptors (GLP-1R) are widely distributed. Various studies have demonstrated the neuroprotective, neurotrophic, neurogenic, and anti-inflammatory effects of GLP-1 under both physiological conditions and experimental models of Parkinson’s disease (PD). As a result, several clinical trials were conducted on PD patients that demonstrated a disease-modifying ability of Exenatide, a GLP-1R agonist. The therapeutic use of GLP-1 is hampered by its short biological half-life. Approaches such as gene therapy can be utilized to ensure a sustained long-term expression of GLP-1 after a single-dose administration. Adeno-associated virus (AAV) has emerged as a safe and efficient tool for gene delivery. The main aim of this project is to design a GLP-1 encoding AAV9 vector that stably expresses and secretes the biologically active form of GLP-1. In the first part of this project, we will design two GLP-1 expression cassettes, with one of them being attached to a nerve growth factor (NGF) signaling peptide. Subsequently, the two GLP-1 expression cassettes will be subcloned into an AAV9 plasmid to form pAAV9-NGF-GLP-1 and pAAV9-GLP-1. The functionality of the two plasmids in regard to expression and secretion will be assessed using CHO/GLP-1RCRE cells. The plasmid showing higher GLP-1 expression and secretion will be chosen for AAV9 production using the triple transfection method. The recombinant AAV9 will then be purified, concentrated, and titrated for further use in vivo and in vitro.