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

项目概要（摘要） 急性和慢性胰腺炎困扰着美国数百万人。小鼠模型显示， 细胞可以去分化后胰腺损伤的祖细胞样细胞类型与导管特征， 称为腺泡-导管化生（ADM）的过程。在没有致癌突变的情况下，ADM病变可以 解决和改革腺泡室。然而，在存在致癌Kras突变的情况下， 病变可以继续去分化为浸润前胰腺上皮内瘤变（PanIN）。的 在损伤和致癌突变的背景下驱动PanIN形成的机制知之甚少， 导致缺乏对抗持续ADM的目标。 我们先前已经通过批量ATAC测序确定了转录因子Fra 1在转录水平上的差异。 仅在突变型Kras和急性炎症的情况下有活性。我们还创造了一种独特的老鼠 在胰腺上皮细胞中表达诱导型突变KRAS（iKras）和Fra 1 loxp等位基因（Fra 1 KO）的模型， 具体方式。我们的初步研究表明，Fra 1缺失减弱ADM的形成， 与FRA 1 WT对照相比，本提案的首要目标是了解如何 FRA 1及其相互作用的伙伴，构成AP-1复合体，在ADM进展的背景下， 突变型Kras和炎症。我的假设是，FRA 1是一个中央调解员的ADM。 细胞自主和非细胞自主效应通过以下方式驱动FRA 1激活 相关的具体目的：（1）研究Fra 1如何在ADM诱导后重塑染色质。 （2）阐明成纤维细胞分泌的G-CSF在胰腺炎期间Fra 1诱导中的作用。我 将使用新型小鼠模型、体外3D腺泡和ADM细胞培养以及最先进的单细胞测序 和染色质沉淀分析来进行这项研究。这一建议还包括一个翻译方面 通过提出G-CSFR作为治疗急性胰腺炎的新的治疗靶点。而且这个 项目包括病理生理学、分子/细胞生物学和定量数据分析。这 该提案为我提供了一个坚实的基础，在实验和定量分析，并扩大了我的 胰腺上皮细胞稳态和可塑性的基础知识。 在经验丰富的导师（Rustgi博士和西姆斯博士）的指导下，我的顾问委员会和丰富的阵列 在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预科培训。 这一重要里程碑的完成将为我作为一名医生科学家的长期目标奠定基础， 在一个学术医学中心进行基础和转化研究，重点是组织炎症，细胞 身份和可塑性，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.