Nuclear Factor-Y in Mouse Pancreatic β-Cells Plays a Crucial Role in Glucose Homeostasis by Regulating β-Cell Mass and Insulin Secretion.

Abstract

Pancreatic β-cell mass and insulin secretion are determined by the dynamic change of transcription factor expression levels in response to altered metabolic demand. Nuclear factor-Y (NF-Y) is an evolutionarily conserved transcription factor playing critical roles in multiple cellular processes. However, the physiological role of NF-Y in pancreatic β-cells is poorly understood. The current study was undertaken in a conditional knockout of <i>Nf-ya</i> specifically in pancreatic β-cells (<i>Nf-ya</i> βKO) to define the essential physiological role of NF-Y in β-cells. <i>Nf-ya</i> βKO mice exhibited glucose intolerance without changes in insulin sensitivity. Reduced β-cell proliferation resulting in decreased β-cell mass was observed in these mice, which was associated with disturbed actin cytoskeleton. NF-Y-deficient β-cells also exhibited impaired insulin secretion with a reduced Ca²⁺ influx in response to glucose, which was associated with an inefficient glucose uptake into β-cells due to a decreased expression of GLUT2 and a reduction in ATP production resulting from the disruption of mitochondrial integrity. This study is the first to show that NF-Y is critical for pancreatic islet homeostasis and function through regulation in β-cell proliferation, glucose uptake into β-cells, and mitochondrial energy metabolism. Modulating NF-Y expression in β-cells may therefore offer an attractive approach for therapeutic intervention.