REGULATION OF ATROPHY-INDUCED PROGENITOR CELLS IN THE GASTRIC CORPUS

胃体中萎缩诱导的祖细胞的调节

• 批准号: 8900276
• 负责人: Jason C Mills
• 金额: $ 39.4万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-11 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8900276
• 关键词: Ablation; Acids; Adult; Affect; Age; Animals; Arthritis; Atrophic; Bioinformatics; Biological Assay; Blood; CD44 gene; Cancer Etiology; Cell Death; Cell Differentiation process; Cell Proliferation; Cell Surface Proteins; Cells; Cessation of life; Characteristics; Chronic; Data; Databases; Developing Countries; Disadvantaged; Disease; E-Cadherin; Epithelial; Epithelial Cells; Epithelium; Estrogens; Frequencies; Gastric Parietal Cells; Gastric ulcer; Gene Expression; Generations; Genes; Goals; Hematopoietic stem cells; Homeostasis; Hour; Human; Hyaluronan; Inflammation; Inflammatory; Injection of therapeutic agent; Injury; Intestines; Kinetics; Label; Learning; Ligands; Malignant Neoplasms; Mediator of activation protein; Metaplasia; Minority; Molecular; Molecular Genetics; Molecular Profiling; Mus; Organ; Pathway interactions; Patients; Pattern; Pharmaceutical Preparations; Pharmacologic Substance; Phosphorylation; Physiological; Population; Process; Pyloric antrum; Regulation; Relative (related person); Research; Risk; Role; STAT3 gene; Secondary to; Selective Estrogen Receptor Modulators; Signal Transduction; Site; Staging; Stem cells; Stomach; Stomach Diseases; System; Tamoxifen; Techniques; Time; Tissues; Toxic effect; Tweens; Undifferentiated; United States; Work; adult stem cell; cancer risk; cell behavior; cost; genetic pedigree; human disease; inhibitor/antagonist; innovation; killings; laser capture microdissection; malignant stomach neoplasm; progenitor; prospective; research study; response; response to injury; stem; stem cell differentiation; stem cell niche; stem cell population; transcription factor; transcriptome sequencing

DESCRIPTION (provided by applicant): Despite recent breakthroughs in identifying prospective stem cell markers (e.g., LGR5) in the intestines and the gastric antrum, relatively little is known about the stem cells of the gastric (body) corpus epithelium. Our overall goal is t better characterize the corpus stem cell under normal conditions and in response to injury. Preliminary data show that the selective estrogen receptor modulator tamoxifen causes ablation of nearly all parietal cells, the acid-secreting lineage, in the mouse stomach within 3 days. Within 6 hours, parietal cells begin to die (atrophy), and progenitor cells in the isthmal stem cel niche of corpus gastric units begin to expand in response. We further find that: 1) the cell surface protein CD44 is required for normal stem cell homeostasis, because proliferation is halved in Cd44-/- relative to wildtype mice; and 2) CD44 marks the expanding isthmal progenitor population. CD44 activates STAT3 and is induced by ERK signaling. We show here that ERK and STAT3 are activated in early expanding progenitors, and levels of the ERK-induced transcription factor EGR1 peak at 3 days, in concert with maximal progenitor expansion. We hypothesize that parietal cell death leads to signals that activate the ERK pathway in isthmal stem/progenitor cells, which causes increased CD44 expression and increased proliferation. In Aim 1, we will determine whether ERK signaling is required for normal stem cell homeostasis and atrophy-induced expansion using both ERK pharmacological inhibition and pedigrees of mice with deficient (Egr1-/-) and overactive (Nab2-/-) ERK. In Aim 2, we will determine whether CD44 is required or sufficient for atrophy-induced progenitor expansion. We will examine kinetics of stem cell expansion in Cd44-/- mice, and we will either activate CD44 in wildtype mice �tamoxifen by injection of the CD44 ligand Hyaluronan or block CD44- Hyaluronan interactions with the inhibitor PEP-1. We will determine if CD44 induces STAT3 and/or if it is required for progenitor expansion. In Aim 3, we will isolate vehicle- and tamoxifen-treated CD44-expressing epithelial progenitor cells by FACS and laser-capture microdissection and then use RNA-Seq to generate gene expression profiles of the normal and atrophy-expanded progenitor cells that will then be integrated bioinformatically with our existing database of global gene expression in stem and progenitor cells. We will also perform limiting dilution assays to determine the stem cell frequency within the epithelial CD44 population. In humans, chronic inflammation can cause parietal cell atrophy, which in turn changes stem cell proliferation and differentiation. Atrophy predispose patients to gastric cancer, but changes in stem cells secondary to inflammation/injury are also an important and understudied aspect of adult diseases in multiple other tissues (e.g., hematopoietic stem cell differentiation changes in arthritis). Thus, the experiments proposed may help us begin to understand stem cell response to injury in multiple tissues and diseases. Finally, our new finding that the key drug tamoxifen causes gastric toxicity warrants further study in humans.

描述（由申请人提供）：尽管最近在鉴定肠和胃窦中的前瞻性干细胞标记（例如，LGR5）方面取得了突破，但对胃（体）体上皮细胞的了解相对较少。我们的总体目标是。更好地表征正常条件下的体干细胞和对损伤的反应初步数据表明，选择性雌激素受体调节剂他莫昔芬会导致几乎所有顶叶的消融。 6小时内，小鼠胃中的胃酸分泌细胞系开始死亡（萎缩），并且胃体单位峡部干细胞生态位中的祖细胞开始响应扩张。发现：1) 细胞表面蛋白 CD44 是正常干细胞稳态所必需的，因为相对于野生型小鼠，Cd44-/- 的增殖减半；2) CD44 标记CD44 激活 STAT3，并由 ERK 信号传导诱导，ERK 和 STAT3 在早期扩增祖细胞中被激活，ERK 诱导的转录因子 EGR1 水平在 3 天达到峰值，与最大祖细胞扩增一致。我们发现壁细胞死亡会导致峡部干细胞/祖细胞中 ERK 通路激活的信号，从而导致 CD44 表达增加和增殖增加。目标 1，我们将使用 ERK 药理抑制和 ERK 缺陷 (Egr1-/-) 和过度活跃 (Nab2-/-) 小鼠的谱系来确定正常干细胞稳态和萎缩诱导的扩增是否需要 ERK 信号传导。 2，我们将确定CD44对于萎缩诱导的祖细胞扩增是否是必需的或足够的。我们将检查干细胞扩增的动力学。 Cd44-/- 小鼠，我们将通过注射 CD44 配体透明质酸激活野生型小鼠中的 CD44，或者阻断 CD44-透明质酸与抑制剂 PEP-1 的相互作用。我们将确定 CD44 是否诱导 STAT3 和/或是否诱导 STAT3。在目标 3 中，我们将通过 FACS 和他莫昔芬处理的表达 CD44 的上皮祖细胞进行分离。激光捕获显微切割，然后使用 RNA-Seq 生成正常和萎缩扩增祖细胞的基因表达谱，然后将其与我们现有的干细胞和祖细胞全局基因表达数据库进行生物信息整合。测定上皮 CD44 群体内干细胞频率的测定在人类中，慢性炎症可导致壁细胞萎缩，从而改变干细胞增殖和分化，使患者易患萎缩。胃癌，但继发于炎症/损伤的干细胞变化也是多种其他组织中成人疾病的一个重要且未被充分研究的方面（例如关节炎中的造血干细胞分化变化）。了解干细胞对多种组织和疾病损伤的反应，我们的新发现是关键药物他莫昔芬会导致胃毒性，值得在人类中进行进一步研究。