Structural, mechanical, and cell biological properties of the ciliary zonule

项目摘要 睫状带的纤维将晶状体悬浮在光轴上，并传递使其变平的力 身体不适。编码小带蛋白的基因突变是综合征和非综合征的基础 对眼睛有深刻影响的疾病。常见的眼部表型包括异位晶状体(晶状体脱位)， 白内障、眼轴延长、近视、青光眼和视网膜脱离。小带的分子组成 最近被阐明，但带状成分的突变最终导致结构 纤维的失效情况尚不清楚。因此，在目标1中，三种小带病(马凡综合征、韦尔-马尔切萨尼病) 综合征和孤立性晶状体异位症)将在小鼠身上建立模型。利用最新开发的成像和 材料测试技术，我们将研究在每种情况下，结构和粘弹性性能如何 突变蛋白的存在(或野生型蛋白的缺失)会影响小鼠的小带。我们 假设眼球的初始加压是小带发育的关键步骤。在《目标2》中，这个 概念将通过测量出生后小鼠的眼压上升和确定 在体外对发育中的眼进行加压会导致早熟的索状纤维的展开。初步 研究发现，交联酶赖氨酸类氧化酶-1(LOXL1)是一种丰富的 小带蛋白质组。在目标3中，我们提出LOXL1衍生的交联链在加强 Zonule。我们将在基因敲除的小鼠模型中验证这一假设。最后，微球晶状体的存在(即 在Weill-Marchesani患者中观察到)(他们在 LTBP2或FBN1，影响纤维拉伸性能的带状蛋白)。我们假设 晶状体表面的索状纤维作用力会影响晶状体的生长。在目标4中，我们将阐明 人晶状体小带的三维结构及其与增殖上皮细胞分布的相关性 在带状附着点周围建立应变场的细胞。

Project Summary The fibers of the ciliary zonule suspend the lens on the optical axis and transmit the forces that flatten it during disaccommodation. Mutations in genes encoding zonular proteins underlie syndromic and non-syndromic conditions that affect the eye profoundly. Common ocular phenotypes include ectopia lentis (lens dislocation), cataract, axial elongation, myopia, glaucoma, and retinal detachment. The molecular composition of the zonule was recently elucidated, but the mechanism by which mutations in zonular components culminate in structural failure of the fibers is unknown. In Aim 1, therefore, three zonulopathies (Marfan Syndrome, Weill-Marchesani Syndrome, and Isolated Ectopia Lentis) will be modeled in mice. Utilizing recently developed imaging and material testing techniques, we will examine how, in each case, the structure and viscoelastic properties of the mouse zonule are affected by the presence of the mutant protein (or absence of the wild-type protein). We hypothesize that the initial pressurization of the eye is a critical step in zonule development. In Aim 2, this notion will be tested by measuring the rise in intraocular pressure in postnatal mice and determining whether pressurization of the developing eye in vitro causes precocious deployment of zonular fibers. Preliminary studies identified the cross-linking enzyme lysyl oxidase-like-1 (LOXL1) as an abundant component of the zonule proteome. In Aim 3, we propose that LOXL1-derived cross-links have a critical role in strengthening the zonule. We will test that hypothesis in a knockout mouse model. Finally, microspherophakia (i.e., the presence of a smaller and more spherical lens) is observed in Weill-Marchesani patients (who harbor mutations in LTBP2 or FBN1, zonular proteins that contribute to the tensile properties of the fibers). We hypothesize that forces exerted by the zonular fibers on the lens surface influence lens growth. In Aim 4, we will elucidate the three dimensional structure of the human zonule and correlate the distribution of proliferating lens epithelial cells with the strain fields established around zonular attachment points.