Agradecimentos: This work was funded by grants from Fundação de Amparo Pesquisa do Estado de São Paulo - Brazil (FAPESP Grant No. 2014/22206-2), Conselho Nacional de Desenvolvimento Científico e Tecnolóogico - Brazil (CNPq Grant No 446957/2014-3), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior CAPES -Brazil. C. Martinez was a recipient of CAPES fellowship (Brazil). The authors thank Prof. Antonio Carlos Boschero for the use of their laboratory facilities for RIA and intracellular calcium measurements and Prof. Marcia Regina Nagaoka for the use of UVITEC gel documentation system. We also thank the Multiuser Multiphoton Confocal Microscopy Laboratory (INFAR-UNIFESP) for the access to confocal microscopy Ver menos

Abstract: Cell-to-cell interactions mediated by intercellular junctions (IJs) are crucial for beta-cell functioning and proper insulin secretion, however, their role in type-2 diabetes is still unclear. This work aimed to evaluate the cellular distribution and expression of proteins associated with adherens (AJs) and gap junctions (GJs) in pancreatic islets of C57BL6 mice fed a high-fat (HF) diet. The administration of HF diet for 30 days induced an increase in body weight, post-prandial glycemia, insulinemia, glucose intolerance, and moderate insulin resistance associated with mild perturbations in insulin secretion. The intercellular content of the AJ-associated proteins (namely, E-, N-cadherins, and a-, ß-catenins) was significantly higher in islet cells of HF-fed mice. Inversely, the gap junctional content of Cx36 was significantly decreased, as revealed by immunofluorescence, which was paralleled by a reduction in the frequency of calcium oscillations in islets of prediabetic mice. In conclusion, the endocrine pancreas displays significant changes in the content of several junctional proteins at the cell-cell contact region following short-term HF diet administration, indicating that IJs may be involved in the adaptive response of beta cells seen during this state Ver menos