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：
7587921
负责人：
LUO LU
金额：
$ 37.35万
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 2012-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7587921
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 Hematoxylin and Eosin Staining Method Histone Deacetylase Homeobox Immunoprecipitation Inflammation Inflammatory Knockout Mice Mediating Molecular NF-kappa B NFKB Signaling Pathway Physiological Platelet Factor 4 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 Tumor Necrosis Factors 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（由申请人提供）：本研究的长期目标是研究生长因子调节和压力诱导的细胞增殖，分化和凋亡对角膜上皮续签过程以及伤口愈合的影响。我们最近发现，与重要基因的CCCTC序列结合的表观遗传调节剂CTCF在角膜上皮中的同型PAX6的调节中起着核心作用。毫无疑问，表皮生长因子（EGF）引起的CTCF激活抑制PAX6表达，以促进角膜上皮更新和伤口愈合过程中的增殖/分化。相反，由于角膜上皮细胞凋亡的增加，高渗透性和紫外线应激诱导的CTCF抑制导致伤口愈合的阻碍。我们还发现，EGF和其他应力通过激活与炎症相关的NF-KB信号通路来调节CTCF的表达。 NF-KB二聚体的亚基特异性激活二分法通过与CTCF基因的转录起始位点的特定元素5'上游相互作用来控制CTCF的表达。我们的结果强烈支持以下观点：EGF和应激诱导的NF-KB激活对角膜上皮细胞命运的二分法作用是由于NF-KB异二聚体的形成和同型二聚体的形成，这些二聚体和同型二聚体分别对CTCF基因转录产生阳性和负面影响。我们假设CTCF受EGF-KB亚基形成的NF-KB二聚体在EGF和应激诱导的角膜上皮细胞中形成的，从而控制了重要基因表达，从而调节角膜上皮上皮增殖和凋亡并影响伤口愈合。 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.这样的研究将提供测试CTCF在介导生长因子和压力诱导的角膜上皮细胞增殖，分化和凋亡方面的生理意义的第一步。此外，结果还将揭示新的调节机制，这些机制描述了为什么不同刺激对NF-KB的激活导致不同的细胞反应。此外，该研究将提供有关NF-KB激活调节CTCF如何介导EGF和应力诱导的细胞命运的机制的新见解。公共健康相关性。角膜上皮更新是由生长因子促进的，并被环境压力延迟，在伤口愈合过程中至关重要，因为它使组织能够充当保护角膜内部的屏障，从而不受疾病和有害环境药物的伤害。这项创新的项目是第一个提供证据的研究，表明生长因子和环境应力都激活了涉及NF-K的重要基因调节剂的炎症信号传导途径：B（核因子-KAPPA B）和CTCF（CCCTC结合因子）。随后，这些基因调节剂控制着决定角膜上皮增殖，分化和凋亡（程序性细胞死亡）的进一步下游基因的表达水平。