Mechanism of MEK Kinase 1 in Mouse Eyelid Development

MEK激酶1在小鼠眼睑发育中的作用机制

• 批准号: 6707297
• 负责人: YING XIA
• 金额: $ 34.54万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6707297
• 关键词: JUN kinase; SDS polyacrylamide gel electrophoresis; actins; biological signal transduction; cell migration; cell proliferation; congenital eye disorder; eyelids; gene expression; gene targeting; genetically modified animals; histogenesis; keratinocyte; laboratory mouse; mass spectrometry; microarray technology; microscopy; mitogen activated protein kinase; phosphorylation; transcription factor; western blottings

DESCRIPTION (provided by applicant): The long-term goal of the proposed study is to elucidate the molecular mechanisms by which signal transduction pathways regulate eye development and ocular surface morphogenesis. Embryonic eyelid closure is essential for normal vertebrate ocular surface morphogenesis; its deficiency in mouse results in eyes open at birth (EOB) and various eye pathologies. Many human congenital diseases, such as conjunctiva-corneal dystrophy, ptosis and microophthalmia, exhibit similarities to pathologies found in mice with EOB and are possibly linked to failure in eyelid development. Understanding the molecular events in eyelid closure may uncover the causes of congenital eye diseases, help develop diagnostic tools and identify targets for possible pharmaceutical intervention. Ablation in mice of the Mekkl gene, encoding a cytoplasmic protein kinase, causes EOB phenotype. MEKK1 ablation results in defects in F-actin formation in developing eyelid epithelium and impairments in keratinocyte cell migration. MEKK1-mediated Jun N-terminal kinase (JNK) cascade leads to phosphorylation of the transcription factor cJun and a concomitant change in gene expression pattern that promotes cell movement and proliferation, but prevents epithelium terminal differentiation. These findings lead to the hypothesis that induction of the MEKK1 pathway in the developing eyelid leads to phosphorylation and activation of members of the AP-1 transcription complex, responsible for changes in gene expression, epithelial cell migration and embryonic eyelid closure. The studies proposed in this application will utilize developing eyelid tissues and cultured keratinoctyes from wild type and Mekk1-/-mice available in our laboratory to investigate the molecular pathways involved in the induction of MEKK1 activity and the regulation of AP-1 function. I propose (1) to elucidate the molecular processes of MEKK1 signaling that lead to keratinocyte migration and mediate eyelid closure; (2) to identify the MEKK1-dependent phosphorylation of AP-1 critical for keratinocyte migration; and (3) to define the role of MEKK1 in the regulation of AP-1 transcription functions pertinent to changes in gene expression during eyelid closure. Results from this work will extend our understanding of the molecular regulation of eyelid development and advance our knowledge on the signaling networks and molecular events critical for epithelial cell migration and eyelid closure.

描述（由申请人提供）：拟议研究的长期目标是阐明信号转导途径调节眼睛发育和眼表形态发生的分子机制。胚胎眼睑闭合对于正常脊椎动物眼表形态发生至关重要。小鼠体内缺乏该物质会导致出生时睁眼（EOB）和各种眼部病变。许多人类先天性疾病，例如结膜角膜营养不良、上睑下垂和小眼症，与患有 EOB 的小鼠中发现的病理相似，并且可能与眼睑发育障碍有关。了解眼睑闭合过程中的分子事件可能会揭示先天性眼病的原因，有助于开发诊断工具并确定可能的药物干预的目标。小鼠中编码细胞质蛋白激酶的 Mekkl 基因的消除会导致 EOB 表型。 MEKK1 去除会导致眼睑上皮发育中 F-肌动蛋白形成缺陷以及角质形成细胞迁移受损。 MEKK1 介导的 Jun N 末端激酶 (JNK) 级联导致转录因子 cJun 磷酸化，并伴随基因表达模式发生变化，从而促进细胞运动和增殖，但阻止上皮细胞末端分化。这些发现导致了这样的假设：在发育中的眼睑中诱导 MEKK1 通路会导致 AP-1 转录复合体成员的磷酸化和激活，从而导致基因表达、上皮细胞迁移和胚胎眼睑闭合的变化。本申请中提出的研究将利用我们实验室现有的野生型和 Mekk1-/- 小鼠的正在发育的眼睑组织和培养的角质细胞来研究涉及 MEKK1 活性诱导和 AP-1 功能调节的分子途径。我建议 (1) 阐明 MEKK1 信号传导导致角质形成细胞迁移并介导眼睑闭合的分子过程； (2) 鉴定对角质形成细胞迁移至关重要的 AP-1 的 MEKK1 依赖性磷酸化； (3) 明确 MEKK1 在调节与眼睑闭合过程中基因表达变化相关的 AP-1 转录功能中的作用。这项工作的结果将扩展我们对眼睑发育的分子调节的理解，并增进我们对对上皮细胞迁移和眼睑闭合至关重要的信号网络和分子事件的了解。