DEVELOPING VISION--THE MECHANISM OF TISSUE REMODELING

我们的长期目标是确定发展的机制， 哺乳动物眼睛中的程序性组织退化。 我们将广泛 使用分子和发展研究技术来确定 在细胞和分子水平上的退化机制。我们将 使用啮齿动物眼睛中的瞳孔膜（PM）作为模型系统， 用来研究组织退化PM提供了一个理想的学习系统 由于其退化发生在小鼠和大鼠出生后， 易于移除和可视化，一般而言，眼睛是可接近的 和非必要的。具体目标： (1)为了确定发育中组织重塑的机制， 在细胞水平上。在哺乳动物中，巨噬细胞 在组织重塑中。我们的初步数据表明，透明细胞， 眼巨噬细胞，是在发展过程中PM消退所必需的 老鼠的眼睛。我们将使用转基因小鼠和眼内 注射作为方法，以防止透明细胞在眼睛中的作用， PM回归以确认该结果。这些实验也会让我们 为了确定透明细胞在治疗过程中是否具有主动或被动作用， 组织重塑肥大细胞的活动也将被调查，因为 它们在其回归期间与PM相关联。 (2)为了确定PM的消退是否涉及细胞凋亡， 组成细胞将确定是否有一些变化 通常与细胞凋亡有关（如核小体的出现）， 阶梯）在回归期间发生在PM的细胞中。如果细胞凋亡 在PM回归期间发生，这将意味着，基于初步证据， 透明细胞能诱导靶细胞凋亡。 (3)为了鉴定介导细胞因子与细胞因子之间相互作用的细胞因子， 透明细胞和目标结构在PM回归。因此我们 将决定之前识别的分子是否可能 表达了介导透明细胞-靶细胞相互作用的候选物， 在适当的模式和时机下 (4)为了证明，使用体内系统， 细胞相互作用取决于（3）中鉴定的分子。我们 将使用转基因小鼠和眼内注射来引入 分子特异性抑制剂，并表明它们是重塑所必需的 眼结构 巨噬细胞是许多疾病状态的核心参与者，包括 炎症性疾病此外，它是正常免疫所必需的。 功能以及伤口愈合，或“非预定”组织重塑。 研究巨噬细胞介导的眼组织退化提供了一个 这是一个独特的机会来了解这种细胞在正常情况下的功能， 过程和潜在地应用巨噬细胞的特征作用 在一个治疗环境中。

It is our long term aim to determine the mechanism of developmentally programmed tissue regression in the mammalian eye. We will make extensive use of molecular and developmental research techniques to determine the mechanism of regression at both the cellular and molecular levels. We will use the pupillary membrane (PM) in the rodent eye as a model system in which to study tissue regression. The PM offers an ideal system for study since its regression occurs after birth in the mouse and rat, the PM is easily removed and visualized, and in general terms, the eye is accessible and non-essential. Specific aims: (1) To determine the mechanism of developmental tissue remodeling in the eye at the cellular level. In mammals, the macrophage has been implicated in tissue remodeling. Our preliminary data suggests that the hyalocyte, an ocular macrophage, is required for regression of the PM during development of the mouse eye. We will use both transgenic mice and intra-ocular injection as methods to prevent the action of hyalocytes in the eye during PM regression to confirm this result. These experiments will also allow us to determine whether the hyalocyte has an active or a passive role during tissue remodeling. Mast cell activities of will also be investigated since they are associated with the PM during its regression. (2) To determine whether regression of the PM involves apoptosis of the constituent cells. It will be determined whether a number of changes usually associated with apoptosis (such as the appearance of a nucleosomal ladder) occur in cells of the PM during regression. If apoptosis does occur during PM regression, it will imply, based on preliminary evidence, that the hyalocyte can induce apoptosis in target cells. (3) To identify cytokines that mediate the interaction between the hyalocytes and target structures during PM regression. To achieve this, we will determine whether previously recognized molecule's that are likely candidates for mediating a hyalocyte-target cell interaction are expressed with the appropriate pattern and timing. (4) To demonstrate, using an in vivo system, that the macrophage-target cell interaction is dependent upon the molecules identified in (3). We will use both transgenic mice and intra-ocular injection to introduce molecule-specific inhibitors and show they are required for remodeling ocular structures. The macrophage is a central player in many disease states including inflammatory disorders. Furthermore, it is required for normal immune function as well as wound healing, or "unscheduled" tissue -remodeling. Studying ocular tissue regression that is macrophage-mediated offers a unique opportunity to learn about the function of this cell in a normal process and potentially to apply the characteristic actions of macrophages in a therapeutic setting.