P30 | NEW INSIGHT IN THE IN VITRO-GENERATION OF INSULIN-PRODUCING CELLS: VAV1 AS A REGULATOR OF PDX1 AND MIR-375 LEVELS DURING DIFFERENTIATION OF HIPSCS INTO Β-CELLS

M. Pierantoni¹, F. Brugnoli¹, V. Zamarian², M. Dell’Aira¹, V. Sordi², V. Bertagnolo¹, S. Grassilli³ | ¹Department of Translational Medicine, University of Ferrara, Ferrara, Italy; ²Diabetes Research Institute, IRCCS San Raffaele Scientific Institute, Milan, Italy; ³Department of Environmental and Prevention Sciences and LTTA Centre, University of Ferrara, Ferrara, Italy

Type 1 diabetes (T1D) is a chronic autoimmune disorder marked by the destruction of pancreatic β-cells, leading to impaired insulin production¹. Transplantation of insulin-producing cells (IPCs) derived from human induced pluripotent stem cells (hiPSCs) represents a promising therapeutic strategy to restore insulin levels in T1D patients. However, differentiation remains heterogeneous, and despite ongoing advances, the efficient production of fully functional β-cells continues to pose a significant challenge². Among the signaling molecules implicated in IPCs generation, Vav1 has recently gained attention due to its expression in adult human β-cells and its essential role in generation of IPCs from biliary tree stem/progenitor cells (hBTSCs) and the transdifferentiation of pancreatic adenocarcinoma (PDAC)derived cells³. Based on these findings, this study investigated the role of Vav1 in the differentiation of hiPSCs into IPCs, focusing on its involvement in modulating key molecules associated with βcell development and function. We found that Vav1 exhibited dynamic expression during differentiation, peaking at the endocrine progenitor (EP) stage and declining in terminally differentiated β-like cells. Silencing Vav1 in endocrine progenitors led to reduced levels of insulin, PDX1, and miR-375, whereas Vav1 overexpression, prior to its natural decline, enhanced their expression. Additionally, in differentiating EP cells, Vav1 negatively regulated Akt, a key factor in β-cell survival, proliferation, apoptosis, and insulin secretion, known to be downregulated by miR-375⁴. These findings identify Vav1 as a pivotal regulator in the transition from pancreatic progenitors to mature IPCs, revealing a potential Vav1/PDX1/miR-375/Akt axis involved in insulin biosynthesis. This regulatory network may offer new opportunities to enhance the efficiency of in vitro β-cell generation for diabetes therapy in T1D patients.