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，特别是在患有严重疾病的患者中。尽管有疾病负担，但治疗充其量仍是支持性的，并辅之以去除可能包括酒精或胆道梗阻性结石在内的诱发因素。此前，我们通过向胰腺募集HO-1+F4/80+细胞，在实验性AP中显示了血红素(上调HO-1，HO-1的血红蛋白假体部分)的保护作用。最近，我们发现泛血红素(PH，一种FDA批准的氯化血红素的水溶性制剂)可以诱导HO-1+细胞快速募集，并治疗正在进行的实验性AP。鉴于这些结果，我们建议检验这一假设，即HO-1下游效应器和氯化血红素激活的细胞转移为AP的治疗提供了替代治疗手段。此外，我们建议确定单核细胞募集和腺泡细胞保护的来源、特征和机制。我们建议的具体目标是：目标1：确定HO-1下游效应分子的治疗作用，并评估细胞治疗在实验性急性胰腺炎中的作用。我们建议确定HO-1下游效应分子和PH诱导的细胞在AP治疗中的治疗作用。目的2：研究HO-1+单核/巨噬细胞在氯化血红素治疗后胰腺炎症中的募集特征。我们建议通过表型和功能分析来确定PH处理后被招募到胰腺的单核细胞的特征，并将其极化为巨噬细胞。目的：明确HO-1+单核细胞保护胰腺腺泡细胞损伤的机制。我们建议确定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：鉴定HO-1+单核细胞通过其募集到炎症胰腺的分子和细胞决定因素。为此，我们建议定义贩运分子的表达，然后通过阻断抗体和/或特定贩运受体基因缺陷的小鼠来评估它们的功能作用。对PH/HO-1下游效应因子的评估以及PH诱导的单核细胞与腺泡细胞的相互作用应有助于明确PH的作用机制，并提供治疗AP的替代方法。相对于淋巴细胞的运输，单核细胞募集到各种炎症部位的定义并不明确，对胰腺的募集更是如此。该项目的发现可能有助于更好地了解疾病的发病机制，以及免疫细胞向炎症的胰腺募集的机制。 与公共卫生相关：急性胰腺炎可遵循一种严重的病程，导致高危患者10%-30%的死亡率，仅在美国，每年就有超过22万人因急性胰腺炎住院。酗酒和胆结石仍然是这种疾病最重要的风险因素。因此，这个项目与急性胰腺炎等胰腺疾病的相关性是巨大的，因为在这些疾病中，没有积极的(除了支持性)治疗方法。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向炎症的胰腺募集的机制。

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.