目的:蛋白磷酸酶1调节抑制亚基1A(PPP1R1A)与胰岛素分泌和糖尿病有关。然而,其在胰腺β细胞功能中的全部意义尚不清楚。本研究旨在使用人胰岛和大鼠INS-1(832/13)细胞阐明PPP1R1A基因在β细胞生物学中的作用。
结果:INS-1细胞中Ppp1r1a的破坏与胰岛素分泌减少和葡萄糖摄取受损有关;然而,细胞活力,ROS,细胞凋亡或增殖完整。关键β细胞功能基因如Ins1、Ins2、Pcsk1、Cpe、Pdx1,Mafa,Isl1,Glut2,Snap25,Vamp2,Syt5,Cacna1a,在Ppp1r1a破坏后观察到Cacna1d和Cacnb3。此外,沉默INS-1细胞中的Pdx1改变PPP1R1A表达,表明PPP1R1A是PDX1的靶基因。用罗格列酮治疗可增加Ppp1r1a表达,而二甲双胍和胰岛素没有效果。人胰岛的RNA-seq分析显示PPP1R1A高表达,与其他内分泌细胞相比,α细胞显示最高水平。肌肉组织的PPP1R1A表达高于胰岛,肝脏,或脂肪组织。共表达分析显示PPP1R1A与胰岛素生物合成相关基因之间存在显著相关性,胞吐机制,和细胞内钙转运。PPP1R1A在人胰岛中的过表达增加了胰岛素分泌和胰岛素蛋白表达上调,MAFA,PDX1和GLUT1,而PPP1R1A的沉默会降低胰岛素,MAFA,和GLUT1蛋白水平。
结论:这项研究为PPP1R1A在调节β细胞功能和葡萄糖稳态中的作用提供了有价值的见解。PPP1R1A为未来的治疗干预提供了一个有希望的机会。
OBJECTIVE: The protein phosphatase 1 regulatory inhibitor subunit 1A (PPP1R1A) has been linked with insulin secretion and diabetes mellitus. Yet, its full significance in pancreatic β-cell function remains unclear. This
study aims to elucidate the role of the PPP1R1A gene in β-cell biology using human pancreatic islets and rat INS-1 (832/13) cells.
RESULTS: Disruption of Ppp1r1a in INS-1 cells was associated with reduced insulin secretion and impaired glucose uptake; however, cell viability, ROS, apoptosis or proliferation were intact. A significant downregulation of crucial β-cell function genes such as Ins1, Ins2, Pcsk1, Cpe, Pdx1, Mafa, Isl1, Glut2, Snap25, Vamp2, Syt5, Cacna1a, Cacna1d and Cacnb3, was observed upon Ppp1r1a disruption. Furthermore, silencing Pdx1 in INS-1 cells altered PPP1R1A expression, indicating that PPP1R1A is a target gene for PDX1. Treatment with rosiglitazone increased Ppp1r1a expression, while metformin and insulin showed no effect. RNA-seq analysis of human islets revealed high PPP1R1A expression, with α-cells showing the highest levels compared to other endocrine cells. Muscle tissues exhibited greater PPP1R1A expression than pancreatic islets, liver, or adipose tissues. Co-expression analysis revealed significant correlations between PPP1R1A and genes associated with insulin biosynthesis, exocytosis machinery, and intracellular calcium transport. Overexpression of PPP1R1A in human islets augmented insulin secretion and upregulated protein expression of Insulin, MAFA, PDX1, and GLUT1, while silencing of PPP1R1A reduced Insulin, MAFA, and GLUT1 protein levels.
CONCLUSIONS: This
study provides valuable insights into the role of PPP1R1A in regulating β-cell function and glucose homeostasis. PPP1R1A presents a promising opportunity for future therapeutic interventions.