Role of hemeoxygenase-1 in experimental acute pancreatitis

描述（由申请人提供）：急性胰腺炎（AP）仍然是一个具有挑战性的临床问题，特别是在重症患者中。尽管有疾病负担，但治疗最多仍是支持性的，并结合清除可能包括酒精或胆道梗阻结石在内的促发因素。以前我们显示了氯化血红素（上调血红素加氧酶-1，HO-1的血红蛋白假体部分）在实验性AP中通过将HO-1+ F4/80+细胞募集到胰腺中的保护作用。最近，我们发现Panhematin（PH，FDA批准的氯化血红素的水溶性制剂）诱导快速HO-1+细胞募集并治疗正在进行的实验性AP。鉴于这些结果，我们提出测试HO-1下游效应物和氯化血红素引发的基于细胞的转移为治疗AP提供替代治疗手段的假设。此外，我们建议定义单核细胞募集和腺泡细胞保护的来源、特征和机制。我们的建议的具体目标是：目的1：确定HO-1下游效应物的治疗作用，并评估基于细胞的治疗在实验性急性胰腺炎中的作用。我们建议确定HO-1下游效应子和PH引发的细胞在治疗AP中的治疗作用。目的2：表征血红素治疗后HO-1+单核细胞/巨噬细胞向发炎胰腺的募集。我们建议使用表型和功能测定来表征PH处理后招募到胰腺的单核细胞，并将其极化为巨噬细胞。目的3：探讨HO-1+单核细胞对胰腺腺泡细胞损伤的保护机制。我们建议在这里，以确定HO-1+单核细胞相互作用和保护腺泡细胞损伤的机制。目的4：表征HO-1+单核细胞被募集到炎症胰腺的分子和细胞决定簇。在这个目标中，我们建议定义贩运分子的表达，然后评估其功能作用，使用阻断抗体和/或小鼠遗传缺陷的特定贩运受体。评估PH/HO-1下游效应子和PH引发的单核细胞与腺泡细胞的相互作用应有助于确定PH的作用机制，并提供治疗AP的替代方法。相对于淋巴细胞运输，单核细胞募集到各种炎症部位并不明确，胰腺的情况更是如此。该项目的发现可能有助于更好地了解疾病的发病机制和炎症胰腺免疫细胞募集的机制。 公共卫生相关性：急性胰腺炎可以遵循导致高危患者10-30%死亡率的严重过程，仅在美国，每年就有超过220，000例住院。酗酒和胆结石仍然是最重要的风险因素的疾病。因此，该项目与胰腺疾病（如急性胰腺炎）的相关性是巨大的，这些疾病没有积极的（除了支持性）治疗。该项目的发现可能导致有效的治疗，并更好地了解疾病的发病机制和免疫细胞招募到炎症胰腺的机制。

DESCRIPTION (provided by applicant): Acute pancreatitis (AP) remains a challenging clinical problem, particularly in patients with severe disease. Despite its disease burden, therapy remains supportive at best coupled with removal of precipitating factors that may include alcohol or biliary obstructing calculi. Previously we showed a protective efect of hemin (hemoglobin prosthetic moiety that upregulates hemeoxygenase-1, HO-1) in experimental AP via recruitment of HO-1+ F4/80+ cells to the pancreas. More recently, we showed that Panhematin (PH, an FDA-approved water soluble formulation of hemin) induces rapid HO-1+ cell recruitment and treats ongoing experimental AP. Given these results, we propose to test the hypothesis that HO-1 downstream effectors and hemin primed cell- based transfers offer alternative therapeutic means for treating AP. Furthermore, we propose to define the source, characteristics, and mechanisms for monocyte recruitment and acinar cell protection. The specific aims of our proposal are: Aim 1: Determine the therapeutic role of HO-1 downstream effectors and evaluate the role for cell-based therapy in experimental acute pancreatitis. We propose to define the therapeutic role of HO-1 downstream effectors and PH-primed cells in treating AP. Aim 2: Characterize HO-1+ monocytes/macrophages recruitment to the inflamed pancreas following hemin treatment. We propose to characterize the monocytes recruited to the pancreas following PH treatment and ases their polarization into macrophages using phenotypic and functional assays. Aim 3: Define the mechanism of HO-1+ monocyte protection against pancreatic acinar cell injury. We propose here to determine mechanisms via which HO-1+ monocytes interact and protect against acinar cell injury. Aim 4: Characterize molecular and cellular determinants via which HO-1+ monocytes are recruited to the inflamed pancreas. In this aim, we propose to define trafficking molecule expression and then assess their functional role using blocking antibodies and/or mice genetically deficient in specified trafficking receptors. Evaluation of PH/HO-1 downstream effectors and interaction of PH-primed monocytes with acinar cells should help define PH's mechanism of action and offer alternate means of treating AP. Relative to lymphocyte trafficking, monocyte recruitment to various inflammatory sites is not as well-defined, and even less so to the pancreas. Findings from this project could lead to a better understanding of disease pathogenesis and mechanisms for immune cell recruitment to the inflamed pancreas. PUBLIC HEALTH RELEVANCE: Acute pancreatitis can follow a severe course that leads to 10-30% mortality in high-risk patients and, in the United States alone, it accounts for over 220,000 hospital admissions every year. Alcohol abuse and gallstones remain the most important risk factors for the disease. Thus the relevance of this project to pancreatic diseases such as acute pancreatitis, where no active (other than supportive) therapy is available, is tremendous. Findings from this project could lead to effective therapy and a better understanding of disease pathogenesis and mechanisms for immune cell recruitment to the inflamed pancreas.