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

项目摘要 睫状小带的纤维将透镜悬挂在光轴上，并在晶状体移动过程中传递使其变平的力 离位编码悬韧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条件。常见的眼部表型包括晶状体异位（透镜脱位）， 白内障、眼轴延长、近视、青光眼和视网膜脱离。悬韧带的分子组成 最近被阐明，但小带成分突变最终导致结构突变的机制， 纤维的失效是未知的。因此，在目的1中，三种悬韧带病（马凡氏综合征，Weill-Marchesani 综合征和孤立性晶状体异位）将在小鼠中建模。利用最近开发的成像技术， 材料测试技术，我们将研究如何，在每种情况下，结构和粘弹性性能的材料， 小鼠悬韧带受到突变蛋白的存在（或野生型蛋白的缺失）的影响。我们 假设眼睛的初始加压是小带发育的关键步骤。在Aim 2中， 这一概念将通过测量出生后小鼠眼内压的升高来检验， 在体外对发育中的眼睛加压导致小带纤维的过早展开。初步 研究确定了交联酶赖氨酰氧化酶样-1（LOXL 1）作为 悬韧带蛋白质组在目标3中，我们提出LOXL 1衍生的交联在增强免疫应答方面具有关键作用。 小带我们将在基因敲除小鼠模型中验证这一假设。最后，微球形晶状体（即，存在 更小和更球形的透镜）在Weill-Marchesani患者中观察到（这些患者在 LTBP 2或FBN 1，有助于纤维拉伸性能的小带蛋白）。我们假设 由小带纤维施加在透镜表面上的力影响透镜的生长。在目标4中，我们将阐明 人晶状体悬韧带的三维结构及其与增殖透镜上皮分布的关系 在悬韧带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.