Lentiviral GLP-1 gene therapy elicits developmental stage-dependent β-cell regeneration in diabetic rats

Pancreatic β-cell differentiation and regenerative capacity differ markedly between developmental stages, with the neonatal pancreas exhibiting high plasticity that enables ongoing progenitor- and ductal-derived β-cell formation, whereas the adult pancreas demonstrates limited neogenic potential. Glucagon-like peptide-1 (GLP-1) promotes β-cell survival, proliferation, and differentiation; however, its developmental stage-specific effects on β-cell regeneration are not fully understood. To investigate this, we generated a third-generation HIV-based lentiviral vector encoding native GLP-1 (LentiGLP-1) under the control of cytomegalovirus (CMV) promoter using the Multisite Gateway^® recombination cloning system. The vector's ability to modulate β-cell differentiation and proliferation was subsequently assessed in neonatal and adult diabetic rat models. Type 2 Diabetes (T2DM) was induced in neonatal rats by administering low-dose streptozotocin (STZ), exploiting the intrinsic plasticity of the developing pancreas, whereas in adult rats, a high-fat diet combined with low-dose STZ was used. LentiGLP-1 administration markedly promoted differentiation of ductal and progenitor cells into insulin-producing β-cells in neonatal rats, accompanied by enhanced β-cell proliferation, demonstrating effective engagement of developmental plasticity. In adults, LentiGLP-1 partially restored β-cell populations through activation of residual progenitors and stimulation of replication in existing β-cells, improving glycemic control and insulin sensitivity. Notably, acinar cells did not contribute to β-cell generation in either neonatal or adult models. These results indicate that GLP-1 exerts developmentally regulated effects on β-cell differentiation, facilitating neogenesis in neonates and partially restoring regenerative capacity in adults. Long term GLP-1 expression, thus represents a promising strategy to restore β-cell mass by proliferation and differentiation, providing insight into its therapeutic potential for diabetes.