ARF controls vascular regression during eye development

描述(由申请人提供)：本提案的主要目标是确定有效的肿瘤抑制因子Arf如何在眼睛发育过程中发挥关键作用，以预防严重的发育性眼病。 在哺乳动物的眼睛发育过程中，玻璃体血管系统为发育中的眼睛提供营养，然后完全内切。失败的人类视觉系统退化是一种被称为持续性增生性初级玻璃体(PHPV)的人类眼病的重要组成部分，其特征是玻璃体中的晶状体后纤维血管组织，晶状体退行性变伴白内障形成，以及视网膜脱离和发育不良。调节人乳头瘤退行性变的分子机制和PHPV的病因在很大程度上还不清楚。然而，偶尔的家族性PHPV临床报告表明，它可能有遗传基础。 最近，我们有了一个意想不到的发现，即Arf肿瘤抑制基因对于小鼠眼睛的正常发育是必不可少的。具体地说，在Arf缺乏的小鼠出生后的头几周，人类视觉系统未能展开，并出现了与PHPV非常相似的眼睛异常。Arf在小鼠眼睛发育过程中的表达模式和时间表明，它可能在促进人类视觉系统退化方面发挥主要作用。Arf基因产物在眼睛发育过程中的功能似乎独立于其已知的“下游”遗传目标P53。这些发现提供了第一个证据，表明ARF调节眼睛发育，并且ARF可能是预防PHPV样眼病的人类视觉系统退化的重要中介。 我们将把对Arf-/-小鼠和新的基因工程小鼠品系的体内研究与体外研究结合起来，以阐明Arf促进发育中眼睛正常的人类视觉系统退化的机制。具体地说，我们的实验将(1)鉴定和鉴定胚胎和出生后眼睛中表达Arf的细胞；(2)确定它是否以细胞自主的方式促进正常的眼睛发育；以及(3)阐明Arf对玻璃体成熟和人类视觉系统退化所需的细胞和分子效应。我们的实验的成功完成将为眼睛中驱动人类视觉系统退化的细胞和分子机制提供新的见解。这将增加我们对ARF功能的了解，并开始阐明PHPV和潜在的其他血管性眼病的分子发病机制。

DESCRIPTION (provided by applicant): The major goal of this proposal is to determine how Arf, a potent tumor suppressor, plays an essential role during eye development to prevent a severe developmental eye disease. During mammalian eye development, the hyaloid vascular system (HVS) supplies nutrients to the developing eye and then completely involutes. Failed HVS regression is an integral component of a human eye disease known as persistent hyperplastic primary vitreous (PHPV), characterized by retrolental fibrovascular tissue in the vitreous, lens degeneration with cataract formation, and retinal detachment and dysplasia. Molecular mechanisms regulating HVS regression and the etiology of PHPV are largely unknown. However, occasional clinical reports of familial PHPV suggest that it may have a genetic basis. Recently, we have made the unexpected discovery that the Arf tumor suppressor gene is essential for the normal development of the mouse eye. Specifically, the HVS fails to involute and eye abnormalities that closely mimic PHPV develop in the first weeks of life in Arf-deficient mice. The pattern and timing of Arf expression during mouse eye development suggest that it may play a primary role in promoting HVS regression. The function of the Arf gene product during eye development appears to be independent of its known "down-stream" genetic target, p53. These findings provide the first evidence that Arf regulates eye development and that Arf may be an essential mediator of HVS regression to prevent a PHPV-like eye disease. We will couple in vivo studies of Arf-/- mice and new genetically-engineered mouse strains with in vitro studies to elucidate the mechanisms by which Arf promotes normal HVS regression in the developing eye. Specifically, our experiments will (1) identify and characterize the Arf-expressing cells in the embryonic and postnatal eye; (2) determine whether it acts in a cell-autonomous manner to promote normal eye development; and (3) elucidate the cellular and molecular effects of Arf that are required for vitreous maturation and HVS involution. The successful completion of our experiments will provide new insight into cellular and molecular mechanisms driving HVS regression in the eye. This should augment our knowledge of Arf function and begin to clarify the molecular pathogenesis for PHPV and potentially other vascular eye diseases.