Lentiviral GLP-1 gene therapy elicits developmental stage-dependent β-cell regeneration in diabetic rats.
This study investigated whether sustained GLP-1 gene delivery could stimulate β-cell regeneration in diabetic rats, and whether regenerative responses differ between neonatal and adult stages. Researchers engineered a third-generation HIV-based lentiviral vector encoding native GLP-1 (LentiGLP-1) under a CMV promoter. Two rat models of type 2 diabetes were used: neonatal rats treated with low-dose streptozotocin (STZ) to exploit developmental pancreatic plasticity, and adult rats subjected to a high-fat diet combined with low-dose STZ. In neonatal diabetic rats, LentiGLP-1 administration markedly promoted differentiation of ductal and progenitor cells into insulin-producing β-cells, accompanied by increased β-cell proliferation. In adult diabetic rats, LentiGLP-1 partially restored β-cell populations via activation of residual progenitors and stimulation of existing β-cell replication, with improvements in glycemic control and insulin sensitivity. Acinar cells were not observed to contribute to β-cell regeneration in either model. A key limitation is that findings are entirely in rodents, and the translational relevance to human β-cell biology remains unestablished. The study provides mechanistic insight into developmentally regulated GLP-1 effects but does not constitute evidence of efficacy in humans.
Why this grade: All experiments were conducted exclusively in neonatal and adult diabetic rat models with no human subjects, clinical data, or human tissue components.
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.
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