Role of CTCF in EGF-Induced Corneal Epithelial Growth

CTCF 在 EGF 诱导的角膜上皮生长中的作用

基本信息

批准号：
8045396
负责人：
LUO LU
金额：
$ 35.5万
依托单位：
LUNDQUIST INSTITUTE FOR BIOMEDICAL INNOVATION AT HARBOR-UCLA MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-02-01 至 2013-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8045396
关键词：
Abbreviations Acetylation Affect Apoptosis Binding CCCTC-binding factor Cell Proliferation Cells Cornea Corneal Injury DNA Binding DNA Sequence Data Deacetylation Disease EMSA EP300 gene Ectoderm Electrophoretic Mobility Shift Assay Elements Enhancers Epidermal Growth Factor Epigenetic Process Epithelial Cell Proliferation Epithelial Cells Eye Development Family member Gene Expression Gene Targeting Genes Genetic Transcription Goals Growth Growth Factor Health Hematoxylin and Eosin Staining Method Histone Deacetylase Homeobox Immunoprecipitation Inflammation Inflammatory Knockout Mice Mediating Molecular NF-kappa B NFKB Signaling Pathway Physiological Play Poly(ADP-ribose) Polymerases Process Promoter Regions Proteins Publishing Regulation Regulator Genes Role Signal Pathway Staining method Stains Stimulus Stress TNF gene TNFRSF5 gene Testing Time Tissues Transcription Initiation Site Transgenic Mice Trichostatin A Tumor Necrosis Factor-alpha Wound Healing cell growth cell motility chromatin immunoprecipitation corneal epithelium dimer environmental agent histone acetyltransferase injured innovation insight novel p65 prolinedithiocarbamate promoter pyrrolidine dithiocarbamate response ultraviolet

项目摘要

DESCRIPTION (provided by applicant): The long-term goal of the present study is to investigate the effects of growth factor-regulated and stress-induced cell proliferation, differentiation and apoptosis on the corneal epithelial renewal process and wound healing. We recently found that CTCF, an epigenetic regulator that binds to the CCCTC sequence of important genes, plays a central role in the regulation of homeobox Pax6 in corneal epithelia. Undoubtedly, epidermal growth factor (EGF)-elicited activation of CTCF inhibits Pax6 expression to promote proliferation/differentiation during corneal epithelial renewal and wound healing. In contrast, hyper-osmotic and UV stress-induced suppression of CTCF results in retardation of wound healing due to increased corneal epithelial apoptosis. We also found that EGF and other stresses regulate CTCF expression through activation of the inflammation- related NF-kB signaling pathway. Subunit-specific activation of NF-kB dimers dichotomously controls CTCF expression by interacting with a specific element 5'-upstream of the transcription initiation site of the CTCF gene. Our results strongly support the notion that the dichotomous effects of EGF- and stress-induced NF-kB activation on corneal epithelial cell fates are due to the formations of NF-kB heterodimers and homodimers that exert positive and negative effects on CTCF gene transcription, respectively. We hypothesize that CTCF is regulated by NF-kB dimers formed by different NF-kB subunits in EGF- and stress-induced corneal epithelial cells, resulting in controls of important gene expressions that regulate corneal epithelial proliferation and apoptosis and affect wound healing. To test the hypothesis, we will undertake three specific aims including: 1) to characterize the effects of EGF- and stress-induced NF-kB activation on the regulation of CTCF, 2) to elucidate the molecular mechanisms of how NF-kB regulates CTCF activity, and 3) to investigate the role(s) of NF-kB in regulating CTCF function to affect corneal wound healing. Such studies will provide the first step towards testing the physiological significance of CTCF in mediating growth factor- and stress-induced corneal epithelial cell proliferation, differentiation and apoptosis. In addition, the results will also reveal novel regulatory mechanisms that describe why activation of NF-kB by different stimuli results in different cellular responses. Furthermore, the study will provide new insight into the mechanisms of how regulation of CTCF by NF-kB activation mediates EGF- and stress-induced cell fates.PUBLIC HEALTH RELEVANCE. Corneal epithelial renewal, which is promoted by growth factors and delayed by environmental stresses, is essential in the wound healing process because it enables the tissue to act as a barrier that protects the corneal interior from becoming injured by diseases and noxious environmental agents. This innovative project is the first study to provide evidence showing that both growth factors and environmental stresses activate an inflammatory signaling pathway involving important gene regulators of NF-K:B (nuclear factor-kappa B) and CTCF (CCCTC binding factor). Subsequently, these gene regulators control the expression levels of further downstream genes that determine corneal epithelial proliferation, differentiation and apoptosis (programmed cell death).

描述（申请人提供）：本研究的长期目标是研究生长因子调节和应激诱导的细胞增殖、分化和凋亡对角膜上皮更新过程和伤口愈合的影响。我们最近发现 CTCF 是一种与重要基因 CCCTC 序列结合的表观遗传调节因子，在角膜上皮同源框 Pax6 的调节中发挥着核心作用。毫无疑问，表皮生长因子（EGF）引起的 CTCF 激活抑制 Pax6 表达，从而促进角膜上皮更新和伤口愈合过程中的增殖/分化。相反，高渗和紫外线应激诱导的 CTCF 抑制会因角膜上皮细胞凋亡增加而导致伤口愈合延迟。我们还发现 EGF 和其他应激通过激活炎症相关 NF-kB 信号通路来调节 CTCF 表达。 NF-kB 二聚体的亚基特异性激活通过与 CTCF 基因转录起始位点 5' 上游的特定元件相互作用，二分性地控制 CTCF 表达。我们的结果强烈支持这样的观点，即 EGF 和应激诱导的 NF-kB 激活对角膜上皮细胞命运的二分效应是由于 NF-kB 异二聚体和同二聚体的形成，它们分别对 CTCF 基因转录产生积极和消极影响。我们假设 CTCF 受到 EGF 和应激诱导的角膜上皮细胞中不同 NF-kB 亚基形成的 NF-kB 二聚体的调节，从而控制调节角膜上皮增殖和凋亡并影响伤口愈合的重要基因表达。为了检验这一假设，我们将实现三个具体目标，包括：1）表征 EGF 和应激诱导的 NF-kB 激活对 CTCF 调节的影响，2）阐明 NF-kB 如何调节 CTCF 的分子机制活性，3) 研究 NF-kB 在调节 CTCF 功能以影响角膜伤口愈合中的作用。此类研究将为测试 CTCF 在介导生长因子和应激诱导的角膜上皮细胞增殖、分化和凋亡中的生理意义迈出第一步。此外，结果还将揭示新的调节机制，描述为什么不同刺激激活 NF-kB 会导致不同的细胞反应。此外，该研究将为 NF-kB 激活调节 CTCF 如何介导 EGF 和应激诱导的细胞命运的机制提供新的见解。公共健康相关性。角膜上皮更新受到生长因子的促进并受到环境压力的延迟，在伤口愈合过程中至关重要，因为它使组织能够充当屏障，保护角膜内部免受疾病和有毒环境因素的伤害。该创新项目是第一项提供证据的研究，表明生长因子和环境压力都会激活炎症信号传导通路，涉及重要的基因调节因子 NF-K:B（核因子-κ B）和 CTCF（CCCTC 结合因子）。随后，这些基因调节因子控制决定角膜上皮增殖、分化和凋亡（程序性细胞死亡）的下游基因的表达水平。