Mouse model for eyelid disease: Congenital blepharophimosis

描述(申请人提供)：眼睑下垂和内翻外翻综合征(BPES)是一种常染色体显性遗传性疾病，其特征是主要影响眼皮发育的头面部缺陷。BPES有两种类型：I型由四个主要特征组成，即眼睑肥大、上睑下垂、内翻内翻和远房花伴卵巢早衰(POF)，导致女性不孕。类型II只包括眼皮畸形，没有性别偏好。患有BPES的人患视力问题的风险增加，如近视(近视)或远视(远视)。他们也可能有眼睛不指向同一方向(斜视)和懒眼(弱视)影响一只或两只眼睛。转录因子叉头盒L2(FOXL2)结构基因的突变导致了70%的BPES。FOXL2基因提供了制造一种蛋白质的指令，这种蛋白质与出生前眼皮和卵巢的发育有关。大约30%的BPES患者没有发现FOXL2结构基因突变；这些人发生这种情况的原因尚不清楚，但FOXL2基因调节可能会改变。在此，我们研究了Notch1信号在眼周间充质细胞(POMC)中的激活作用，这些细胞参与了包括提肌间充质细胞(POMC)、提肌间充质细胞(POMC)和提M？肌间充质细胞(POMC)在内的眼睑结构的形成。在不同发育阶段的多西环素(Dox)脉冲诱导下，NOTCH1胞内区(N1-ICD)在一个新的三重转基因小鼠品系Kera-RTTA/Teto-Cre/R26FloxedN1-ICD(KR/TC/R26fN1-ICD)的POMC(这里称为POMCN1-ICD)中有条件地错误表达。这些三重KR/TC/R26fN1-ICD小鼠表现出与人类BPES相似的眼皮异常。我们的初步数据表明，在眼睑形态发生过程中，N1-ICD的表达导致POMCs中FOXL2和平滑肌分化标志基因α-SMA的表达特异性降低。我们的初步研究允许我们提出这样的假设，即持续的Notch信号干扰POMC细胞中FOXL2下调而导致眼睑张开的提肌M？Eller平滑肌的形成。在这一应用中，我们将进一步将KR/TC/R26fN1-ICD三转基因小鼠作为研究先天性BPES(Aim1)发病机制的一种新的动物模型。我们还将描绘一条导致FOXL2下调以及随后在胚胎眼皮发育过程中提肌平滑肌畸形的分子途径(AIM2)。

DESCRIPTION (provided by applicant): Blephar-ophimosis, Ptosis, and Epi-canthus inversus Syndrome (BPES) is an autosomal dominant genetic disorder characterized by craniofacial defects that mainly affect the development of the eyelids. There are two types of BPES: Type I consists of the four major features of blepharophimosis, ptosis, epicanthus inversus, and telecanthus plus premature ovarian failure (POF), leading to infertility in woman. Type II consists of only the eyelid malformations without gender preference. People with BPES are at an increased risk of developing vision problems such as nearsightedness (myopia) or farsightedness (hyperopia). They may also have eyes that do not point in the same direction (strabismus) and lazy eye (amblyopia) affecting one or both eyes. Mutations in the transcription factor forkhead box L2 (FOXL2) structure gene cause 70 percent of BPES. The FOXL2 gene provides instructions for making a protein that is involved in the development of the eyelids and the ovaries before birth. Approximately 30 percent of people with BPES do not have an identified FOXL2 structure gene mutation; the cause of the condition in these people is unknown but FOXL2 gene regulation maybe altered. Herein, we have investigated the effects of Notch1 signaling activation in peri-ocular mesenchymal cells (POMC) which contribute to the formation of the lid-specific structures including levator M¿ellersmooth muscle, tarsus, and meibomian glands. Notch1 intracellular domain (N1-ICD) was conditionally mis-expressed in POMC (here refer to as POMCN1-ICD) of a novel triple transgenic mouse strain, namely Kera-rtTA/tetO-Cre/R26floxedN1-ICD (KR/TC/R26fN1- ICD), by pulse induction of doxycycline (Dox) at different developmental stages. These triple KR/TC/R26fN1-ICD mice exhibited variegation of eyelid anomalies resembling BPES in humans. Our preliminary data showed that N1-ICD expression caused specific reduction of FoxL2 and smooth muscle differentiation marker gene, alpha-smooth actin (a-SMA) expressions in POMCs during eyelid morphogenesis. Our preliminary studies allow us to propose the hypotheses that sustained Notch signaling disturbs the formation of levator M¿eller smooth muscle responsible for eyelid opening by down-regulation of FoxL2 in the POMC cells. In this application, we will further characterize KR/TC/R26fN1-ICD triple transgenic mouse as a novel animal model to study the pathogenesis of congenital BPES (Aim1). We will also delineate a molecular pathway that leads to the down-regulation of FoxL2 and subsequent malformation of the levator M¿ellersmooth muscle during embryonic eyelid development (Aim2).