Vav1 Sustains the Expression of Insulin, PDX1 and miR-375 During Differentiation of hiPSCs to β Cells: A Potential Target to Improve the In Vitro Generation of Insulin-Producing Cells Marina Pierantoni, Valentina Zamarian, Federica Brugnoli, Silvia Grassilli, Laura Monaco, et al. Tissue Engineering and Regenerative Medicine, 2026 Backround: Human-induced pluripotent stem cells (hiPSCs) have emerged as a promising source of transplantable insulinproducing cells (IPCs) to restore insulin levels in Type 1 Diabetes (T1D) patients. Despite progress, obtaining fully functional β cells from hiPSCs remains challenging, underscoring the need to better understand the intracellular mechanisms involved. We investigated here the potential role of Vav1, a multidomain protein that we identified as crucial for the maturation of human biliary stem cells (hBTSCs) into β-like cells and in the trans-differentiation of pancreatic adenocarcinoma (PDAC) cells into IPCs; Methods: Levels and subcellular localization of Vav1 were investigated throughout a seven-step differentiation process of hiPSCs to β cells. Vav1expression was forcedly modulated in pancreatic progenitors, and the potential effects were evaluated on insulin production and on PDX1, miR-375, and Akt, key regulators of β cells generation; RESULTS. Vav1 showed dynamic modulation, with pancreatic precursor cells requiring adequate levels of the protein to generate IPCs. Results: Vav1 sustains the expression of PDX1, a primary regulator of insulin expression, and of its target miR-375, essential for determining β cell mass. Furthermore, Vav1 reduction correlated with increased activation of Akt, which regulates cell survival and insulin secretion in β cells and is down-regulated by miR- 375. Conclusion: Our findings suggest the existence of a Vav1/PDX1/miR-375/Akt axis as part of the complex network orchestrating the generation of functional β cells. These insights indicate that strategies aimed at specifically modulating Vav1 levels may positively impact the generation of IPCs in vitro and, ultimately, β cell replacement therapy for T1D.
Liraglutide Treatment Reverses Unconventional Cellular Defects in Induced Pluripotent Stem Cell–Derived β-Cells Harboring a Partially Functional WFS1 Variant Silvia Torchio, Gabriel Siracusano, Federica Cuozzo, Valentina Zamarian, Silvia Pellegrini, et al. Diabetes, 2025 Wolfram syndrome 1 (WS1) is a rare genetic disorder caused by WFS1 variants that disrupt wolframin, an endoplasmic reticulum-associated protein essential for cellular stress responses, Ca2+ homeostasis, and autophagy. Here, we investigated how the c.316-1G>A and c.757A>T WFS1 mutations, which yield partially functional wolframin, affect the molecular functions of β-cells and explored the therapeutic potential of the glucagon-like peptide 1 receptor (GLP-1R) agonist liraglutide. Pancreatic β-cells obtained from patient-derived induced pluripotent stem cells (iPSCs) carrying this WFS1 variant exhibited reduced insulin processing and impaired secretory granule maturation, as evidenced by proinsulin accumulation and decreased prohormone convertase PC1/3. Moreover, they exhibited dysregulated Ca2+ fluxes due to altered transcription of Ca2+-related genes, including CACNA1D, and significantly reduced SNAP25 levels, leading to uncoordinated oscillations and poor glucose responsiveness. Affected cells also showed increased autophagic flux and heightened susceptibility to inflammatory cytokine-induced apoptosis. Notably, liraglutide treatment rescued these defects by normalizing Ca2+ handling, enhancing insulin processing and secretion, and reducing apoptosis, likely through modulation of the unfolded protein response. These findings underscore the importance of defining mutation-specific dysfunctions in WS1 and support targeting the GLP-1/GLP-1R axis as a therapeutic strategy. Article Highlights The molecular basis of WFS1-related mutations remains poorly investigated, and no definitive therapies exist for Wolfram syndrome 1. We dissected the molecular defects associated with c.316-1G>A and c.757A>T WFS1 mutations in patient-derived induced pluripotent stem cell islets and analyzed whether they are potential therapeutic targets of the glucagon-like peptide 1 receptor agonist liraglutide. We found impaired insulin granule maturation, altered Ca2+ fluxes, increased autophagic activity, and heightened susceptibility to inflammatory apoptosis in mutated cells. Liraglutide restored critical β-cell functions suggesting a route for personalized therapy based on WFS1 mutations.
SID/SIEDP expert consensus on optimizing clinical strategies for early detection and management of wolfram syndrome Giulio Frontino, Maurizio Delvecchio, Sabrina Prudente, Valeria Daniela Sordi, Piero Barboni, et al. Journal of Endocrinological Investigation, 2025 Wolfram Syndrome (WFS) is a rare, multisystemic, degenerative disease leading to premature death. Clinical and genetic heterogeneity makes WFS diagnosis and management challenging. The Italian Society of Diabetes (SID) and the Italian Society for Pediatric Endocrinology and Diabetology (SIEDP) convened an expert panel of professional healthcare practitioners to provide up-to-date knowledge about the pathophysiology, clinical presentation and treatment of WFS, and recommendations for the earlydetection and optimal disease management. The consensus recommends the revision of diagnostic protocols to include genetic testing and comprehensive multidisciplinary evaluations to ensure accurate diagnosis of WFS, advocates for personalized management plans tailored to the unique needs of each patient, with an emphasis on exploring new potential drug therapies. A holistic care model that addresses the medical, psychological, and social challenges faced by patients with WFS and their families is strongly endorsed. The opinion underscores the importance of educating healthcare professionals about WFS to enhance early diagnosis and intervention, aiming to improve outcomes for patients through practical and evidence-based clinical strategies.
Blockade of CD155 and CD276 by Monoclonal Antibodies Fosters Immune Tolerance and Promotes Stable Engraftment of iPSC-Derived Islets in Allogeneic Humanized Mice G. Siracusano, F. Deambrogio, V. Sordi, M. Malnati, L. Piemonti, et al. Transplant International, 2025 Induced pluripotent stem cell (iPSC)-derived pancreatic islets represent a promising therapeutic approach for restoring insulin independence in type 1 diabetes (T1D). However, their clinical success remains critically dependent on overcoming rejection mediated by innate and adaptive immune responses. Current immunosuppressive therapies pose significant long-term risks and only partially control alloimmune and autoimmune reactions. Targeted immunomodulation using monoclonal antibodies is a safer, more precise alternative. Here, we explored the impacts of blocking CD276 (B7-H3) and CD155 (PVR), activating ligands involved in immune recognition and regulation, on the survival and in vivo maturation of iPSC-derived endocrine progenitors (EPs) into functional pancreatic islets. Using a humanized mouse model, we demonstrated that dual blockade of CD276 and CD155 markedly reduced NK cell-mediated graft rejection, prevented CD14 + monocyte activation, and limited overall immune infiltration. In addition, CD155 blockade increased PD-1 levels on activated CD8 + T cells and significantly enhanced regulatory T cell (Treg) expansion and function, thereby promoting graft tolerance. Combined treatment prolonged engraftment and facilitated the maturation of EPs into functional, insulin-secreting cells, as indicated by increased human C-peptide levels and glucose responsiveness 4 weeks post-transplantation. Our findings highlight CD276/CD155 blockade as a novel immunomodulatory strategy to support tolerance and the functional maturation of iPSC-derived pancreatic grafts in T1D.
