WNT5a Signaling in Stage Specific Alveolar Epithelial Cell Differentiation

摘要 胎儿器官的成熟以支持出生后的生命是一个非常重要的过程。然而，在大多数情况下， 对该过程的研究/理解很少。在肺，成熟失败是一个重大的健康 问题.在早产儿中，它可引起呼吸窘迫综合征（RDS）和支气管肺疾病。 发育不良（BPD）。 我们已经发现非典型WNT配体WNT 5a的功能丧失抑制肺成熟。 两个关键缺陷包括抑制肺泡1型上皮细胞（AEC 1）分化和抑制肺泡上皮细胞增殖。 肌成纤维细胞（AMF）分化。重要的是，匡威亦然; Wnt 5a功能获得性 促进肺成熟和AEC 1分化。在额外的初步研究中，我们表明， WNT 5a受体ROR 1和ROR 2的功能导致与WNT 5a相似的肺成熟缺陷 功能丧失WNT 5a激活钙/钙调蛋白依赖性蛋白激酶II（CaMKII）， 胞质信号转导分子抑制CaMKII也破坏肺成熟。基于 综合初步调查结果，我们提出以下假设： 假设：WNT 5a-ROR信号传导是肺成熟的关键调节因子。这条通路控制着 结构，细胞和分子步骤，最终有助于功能肺的形成。 在本申请中，我们将重点关注AEC 1和AMF分化，作为两个关键的细胞机制 在肺成熟期间由WNT 5a控制。多种组织特异性条件性体内模型， 肺成熟过程中AEC和AMF中靶向Wnt 5a和Rors将用于确定它们的细胞类型 在囊泡和肺泡阶段的特定功能。这些研究还将确定CaMKII的作用， WNT 5a介体。我们提出以下具体目标。 具体目标1。确定肺成熟过程中AEC中WNT 5a信号转导的功能。 具体目标2。确定肺成熟过程中AMF中WNT 5a信号转导的功能。 具体目标3。确定CaMK Ⅱ作为细胞内下游介导因子的作用 WNT 5a信号在肺成熟中的作用 健康相关性：肺成熟是出生后生存的生存要求。如果成功， 这项研究的结果可能会对理解这些机制产生有意义的影响， 潜在的肺成熟，这可能有助于开发更有效的新型肺治疗方法。 早产儿的疾病。确定WNT 5a、RORs和CaMKII在肺成熟中的作用， 进一步表明在不同水平的信号转导的治疗目标，并可能允许更有选择性的 这个过程的调制。

ABSTRACT Maturation of fetal organs to support life after birth is a significantly vital process. However, in most cases, this process is poorly investigated/understood. In the lung, failure in maturation is a significant health problem. In preterm infants, it can cause Respiratory Distress Syndrome (RDS) and BronchoPulmonary Dysplasia (BPD). We have found that loss-of-function for a non-canonical WNT ligand, WNT5a inhibits lung maturation. Two key defects include inhibition of alveolar type 1 epithelial cell (AEC1) differentiation and alveolar myofibroblast (AMF) differentiation. Importantly, the converse is also true; Wnt5a gain-of-function promotes lung maturation & AEC1 differentiation. In additional preliminary studies, we show that loss-of- function of WNT5a receptors, ROR1 and ROR2, results in similar defects in lung maturation as in WNT5a loss-of-function. WNT5a activates Calcium/calmodulin-dependent protein kinase II (CaMKII) an important cytoplasmic signal transduction molecule. Inhibiting CaMKII also disrupts lung maturation. Based on the collective preliminary findings, we propose the following hypothesis: HYPOTHESIS: WNT5a-ROR signaling is a key regulator of lung maturation. This pathway controls the structural, cellular and molecular steps that ultimately contribute to the formation of functional lungs. In this application, we will focus on AEC1 and AMF differentiation, as two key cellular mechanisms controlled by WNT5a during lung maturation. Multiple tissue specific, conditional in vivo models that target Wnt5a and Rors in AEC and AMF during lung maturation will be used to determine their cell-type specific functions in saccular and alveolar stages. The studies will also determine the role of CaMKII as WNT5a mediator. We propose the following Specific Aims. Specific Aim 1. To Determine the Function of WNT5a Signaling in AEC During Lung Maturation. Specific Aim 2. To Determine the Function of WNT5a Signaling in AMF During Lung Maturation. Specific Aim 3. To Determine the Role of CaMKII as a Downstream Intracellular Mediator of WNT5a Signaling in Lung Maturation. Health Relevance: Lung maturation is an existential requirement for surviving after birth. If successful, the results of this research will likely have a meaningful impact on understanding the mechanisms underlying lung maturation, which may help in development of more effective & novel therapies for lung diseases in premature infants. Determining the role of WNT5a, RORs & CaMKII in lung maturation could further suggest therapeutic targets at different levels of signal transduction & may allow for more selective modulation of this process.