The stiffness of three-dimensional biomimetic matrices regulates insulin secretion via the Piezo1 mechanosensitive ion channel

Introduction The extracellular matrix (ECM) within the pancreatic microenvironment plays an integral role in the pathogenesis of diabetes. However, how matrix stiffness regulates islet β-cell function through mechanosensitive ion channels remains poorly understood. Methods A three-dimensional biomimetic islet culture system with graded matrix stiffness was established using hyaluronic acid methacrylate (HAMA) hydrogels with different crosslinking times. MIN6 insulin-secreting cells were encapsulated in soft and stiff HAMA matrices, and cell viability, Piezo1 expression, intracellular Ca 2+ levels, β-cell function-related gene expression, and glucose-stimulated insulin secretion (GSIS) were evaluated. Pharmacological modulation of mechanosensitive ion channels and Piezo1 knockdown were used to investigate the potential role of Piezo1 in stiffness-dependent β-cell responses. RNA sequencing and pathway enrichment analyses were performed to identify signaling pathways associated with matrix stiffness. In addition, stiff or soft matrix-encapsulated MIN6 cells were transplanted into diabetic mice to evaluate in vivo glucose regulation and biocompatibility. Results Stiffer HAMA hydrogels significantly increased Piezo1 expression in MIN6 cells and were associated with elevated intracellular Ca 2+ levels. Compared with the soft matrix, the stiff matrix significantly increased the expression of β-cell function-related genes, including Insulin, Pdx1, Mafa, and Nkx6-1, and enhanced insulin secretion under both basal and glucose-stimulated conditions. Pharmacological activation of Piezo1 in the soft matrix partially mimicked the effects of the stiff matrix, whereas inhibition of mechanosensitive ion channels reduced insulin-associated signals and β-cell function-related gene expression. RNA-seq and pathway enrichment analyses identified HIF-related signaling and metabolic pathways as potential molecular responses to matrix stiffness. However, the present data did not establish a direct mechanistic relationship between HIF signaling and Piezo1. In diabetic mice, transplantation of stiff matrix-encapsulated MIN6 cells was associated with improved blood glucose control during the observation period and showed good in vivo biocompatibility. Discussion These findings indicate that matrix stiffness can modulate β-cell function and glucose-responsive insulin secretion within a three-dimensional microenvironment. Overall, this study provides evidence that biomechanical properties of the three-dimensional ECM may influence β-cell function and highlights matrix mechanics as a potential regulatory component of the islet microenvironment.