TCF7L2 and Insulin Secretion

What is it about?

This study investigates the role of TCF7L2 in regulating insulin secretion and diabetes risk. The expression of TCF7L2 was confirmed in mouse islets, MIN6 and INS-1(832/13) cells. Silencing of TCF7L2 in mouse islets resulted in a decrease in basal and glucose-stimulated insulin release, while insulin release stimulated by cell depolarization with high concentrations of K+ was unaffected. TCF7L2 silencing also resulted in a decrease in the number of docked vesicles and decreased Munc18-1 and ZnT8 mRNA levels, while ATP/ADP ratio and cytosolic free Ca2+ concentration increased. These findings suggest that TCF7L2 is involved in maintaining cell gene expression regulating secretory granule fusion and that defective insulin exocytosis may underlie increased diabetes incidence in carriers of the at-risk TCF7L2 alleles.

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Why is it important?

The study aimed to investigate the role of TCF7L2 in regulated insulin secretion and to identify potential molecular mechanisms involved. Key Takeaways: 1. TCF7L2 is involved in maintaining expression of β-cell genes regulating secretory granule fusion. 2. Defective insulin exocytosis may underlie increased diabetes incidence in carriers of the at-risk TCF7L2 alleles. 3. Silencing of TCF7L2 in mouse islets resulted in decreased insulin release in response to high glucose levels. 4. Insulin secretion stimulated by cell depolarization with high concentrations of K+ was unaffected by TCF7L2 depletion. 5. The study provides insight into the potential molecular mechanisms underlying the link between TCF7L2 and type 2 diabetes.