Elucidating the role of Fra1 in pancreatic Kras-driven acinar to ductal metaplasia

项目摘要(摘要) 在美国，数以百万计的人患有急性和慢性胰腺炎。小鼠模型显示腺泡细胞 胰腺损伤后细胞可去分化为具有导管特征的祖细胞样细胞类型 这一过程称为腺泡至导管化生(ADM)。在没有致癌突变的情况下，ADM皮损可以 解决和改革腺泡隔室。然而，在存在致癌的Kras突变的情况下，ADM 病变可继续去分化为侵袭前胰腺上皮内瘤变(Panin)。这个 在损伤和致癌突变的背景下驱动Panin形成的机制还知之甚少， 导致缺乏打击顽固的ADM的目标。 我们之前已经通过批量ATAC-测序确定了转录因子Fra1是差异表达的 仅在突变的Kras和急性炎症的背景下有效。我们还创造了一种独特的鼠标 胰腺上皮细胞表达诱导性突变KRAS(IKras)和Fra1loxP等位基因(Fra1KO)的模型 具体的方式。我们的初步研究表明，Fra1的丢失可以减少ADM的形成和 间质发生与Fra1WT对照的比较。这项提案的首要目标是了解如何 FRA1及其相互作用的伙伴组成AP-1复合体，在以下背景下管理ADM的进展 突变克拉斯和炎症。我的假设是FRA1是ADM的中心调节因子。我会调查的 细胞自主和非细胞自主影响通过以下途径驱动Fra1的激活 相关的特定目标：(1)研究Fra1在诱导ADM后如何重塑染色质 (2)阐明成纤维细胞分泌的G-CSF在胰腺炎时FRA1诱导中的作用。我 将使用新的小鼠模型、体外3D腺泡和ADM细胞培养以及最先进的单细胞测序 并用染色质沉淀法进行本研究。这项提议还包含翻译方面的内容。 提出G-CSFR作为治疗急性胰腺炎的新靶点。此外，这一点 该项目结合了病理生理学、分子/细胞生物学和定量数据分析的各个方面。这 提案为我在实验和定量分析方面提供了坚实的基础，并拓宽了我的 胰腺上皮细胞动态平衡和可塑性的基础知识。 在经验丰富的导师(Rustgi博士和Sims博士)、我的顾问委员会和有钱人的指导下 有了哥伦比亚大学欧文医学中心的资源，我将能够完成我的博士前博士培训。 这一重要里程碑的完成将为我作为一名内科科学家的长期目标奠定基础 学术医学中心的基础和翻译研究，重点是组织炎症、细胞 特性和可塑性，以及组织再生。

PROJECT SUMMARY (ABSTRACT) Acute and chronic pancreatitis afflict millions of individuals in the US. Mouse models have revealed that acinar cells can de-differentiate after pancreatic injury to a progenitor-like cell type with ductal characteristics in a process termed acinar-to-ductal metaplasia (ADM). In the absence of oncogenic mutations, ADM lesions can resolve and reform the acinar compartment. However, in the presence of oncogenic Kras mutations, the ADM lesions can continue to de-differentiate to a pre-invasive pancreatic intraepithelial neoplasia (PanIN). The mechanisms that drive PanIN formation in the context of injury and oncogenic mutations are poorly understood, resulting in an absence of targets to combat the persistent ADM. We have identified previously through bulk ATAC-sequencing that the transcription factor Fra1 is differentially active only in the context of mutant Kras and acute inflammation. We have also generated a unique mouse model expressing inducible mutant KRAS (iKras) and Fra1 loxp alleles (Fra1 KO) in a pancreatic epithelial- specific manner. Our preliminary studies demonstrate that Fra1 loss attenuates ADM formation and stromagenesis compared to the FRA1 WT controls. The overarching goal of this proposal is to understand how FRA1 and its interacting partners, which constitute the AP-1 complex, govern ADM progression in the context of mutant Kras and inflammation. My hypothesis is that FRA1 is a central mediator of ADM. I will investigate the cell autonomous and non-cell autonomous effects driving FRA1 activation through the following interrelated Specific Aims: (1) Investigate how Fra1 remodels chromatin in ADM after induction of pancreatitis; (2) Elucidate the role of fibroblast-secreted G-CSF in Fra1 induction during pancreatitis. I will use novel mouse models, ex vivo 3D acinar and ADM cell cultures, and state-of-the-art single-cell sequencing and chromatin precipitation assays to conduct this study. This proposal also encompasses a translational aspect by proposing G-CSFR as a novel therapeutic target for the treatment of acute pancreatitis. Additionally, this project incorporates aspects of pathophysiology, molecular/cellular biology, and quantitative data analysis. This proposal provides me with a robust foundation in both experimental and quantitative analysis and broadens my fundamental knowledge of pancreatic epithelial cell homeostasis and plasticity. With the guidance from experienced mentors (Drs. Rustgi and Sims), my advisory committee and the rich array of resources at Columbia University Irving Medical Center, I will be able to complete my predoctoral PhD training. Completion of this critical milestone will set the stage for my long-term goal as a physician-scientist who conducts basic and translational research in an academic medical center with a focus on tissue inflammation, cellular identity and plasticity, and tissue regeneration.