目的:对胰腺腺泡/中心腺泡单位的遗传规范了解甚少。生长因子独立-1(Gfi1)是一种锌指转录抑制因子,可调节造血干细胞的维持,前T细胞分化,粒细胞的形成,内耳毛细胞,以及肠道分泌细胞类型的发育。由于GFI1/Gfi1在人类和啮齿动物胰腺中表达,我们描述了Gfi1在小鼠胰腺发育中的潜在功能。
方法:在组织学和分子水平上分析Gfi1基因敲除小鼠,包括qRT-PCR,原位杂交,免疫组织化学,和电子显微镜。
结果:Gfi1的丢失影响了胰腺腺泡/中心腺泡单元的形成和结构。Gfi1-null胰腺的组织学和超微结构分析显示,与野生型同窝动物相比,Gfi1-/-小鼠的胰腺腺泡细胞和中心腺泡细胞(CAC)水平存在特定缺陷。胰腺内分泌分化,胰岛建筑,功能不受影响。在Gfi1-/-胰腺的鼠次级转变(E13.5-E14.5)期间,器官结构域的图案化和导管细胞的形成通常发生。然而,在妊娠后期(E18.5),在Gfi1-/-小鼠中,CAC的细胞标志物的表达大幅降低,由腺泡/中心腺泡单元的电子显微镜成像证实。CAC的减少与外分泌器官缺陷相关。出生后,Gfi1缺乏导致严重的胰腺腺泡发育不良,包括颗粒损失,自溶液泡化,以及增殖和凋亡反应。
结论:Gfi1在调节胰腺CAC的发育和胰腺腺泡细胞的功能中起重要作用。
OBJECTIVE: The genetic specification of the compartmentalized pancreatic acinar/centroacinar unit is poorly understood. Growth factor independence-1 (Gfi1) is a zinc finger transcriptional repressor that regulates hematopoietic stem cell maintenance, pre-T-cell differentiation, formation of granulocytes, inner ear hair cells, and the development of secretory cell types in the intestine. As GFI1/Gfi1 is expressed in human and rodent pancreas, we characterized the potential function of Gfi1 in mouse pancreatic development.
METHODS: Gfi1 knockout mice were analyzed at histological and molecular levels, including qRT-PCR, in situ hybridization, immunohistochemistry, and electron microscopy.
RESULTS: Loss of Gfi1 impacted formation and structure of the pancreatic acinar/centroacinar unit. Histologic and ultrastructural analysis of Gfi1-null pancreas revealed specific defects at the level of pancreatic acinar cells as well as the centroacinar cells (CACs) in Gfi1-/- mice when compared with wild-type littermates. Pancreatic endocrine differentiation, islet architecture, and function were unaffected. Organ domain patterning and the formation of ductal cells occurred normally during the murine secondary transition (E13.5-E14.5) in the Gfi1-/- pancreas. However, at later gestational time points (E18.5), expression of cellular markers for CACs was substantially reduced in Gfi1-/- mice, corroborated by electron microscopy imaging of the acinar/centroacinar unit. The reduction in CACs was correlated with an exocrine organ defect. Postnatally, Gfi1 deficiency resulted in severe pancreatic acinar dysplasia, including loss of granulation, autolytic vacuolation, and a proliferative and apoptotic response.
CONCLUSIONS: Gfi1 plays an important role in regulating the development of pancreatic CACs and the function of pancreatic acinar cells.