Milk osteopontin, a nutritional therapeutic intervention for alcoholic hepatitis

描述(申请人提供)：酒精性肝病是世界范围内肝脏疾病和死亡的主要原因；因此，迫切需要开发新的治疗干预措施。酒精性肝病的发生和发展的关键事件是肠肝相互作用的结果。牛奶骨桥蛋白通过维持上皮屏障功能、提供粘膜防御、防止脓毒症和炎症反应来保护肠道。到目前为止，牛奶骨桥蛋白在预防酒精性肝病中的作用还没有确定。我们认为使用牛奶骨桥蛋白的营养疗法可以预防酒精性肝损伤。在本申请中，我们将重点检验中心假设：“补充牛奶骨桥蛋白可以预防酒精性肝病，因为它的肠道保护和抗脂肪作用”。特别是，我们假设牛奶骨桥蛋白将：1) 靶向肠道-肝轴，保护肠道粘膜屏障，阻止革兰氏阴性菌从肠道转移到门静脉循环，从而降低脂多糖水平；2)通过靶向脂肪酸代谢，防止脂肪变性和肝脏损伤 减少脂多糖介导的枯否细胞活化和肿瘤坏死因子的产生；以及3)通过增加自噬来避免肝脏脂肪变性、炎症和肝损伤，自噬是最近发现的调节脂肪变性的一种途径。利用酒精诱导的肝损伤模型，小鼠将被 用牛奶骨桥蛋白治疗，以评估其治疗潜力。为了证明我们的假设，我们计划了三个具体目标。在目标1中，我们将分析牛奶骨桥蛋白是否能阻止乙醇介导的肠道通透性、细菌易位和脂多糖利用率的增加。 慢性Lieber-DeCarli模型和葡聚糖硫酸钠治疗将被使用。在目标2中，首先，我们将确定牛奶骨桥蛋白是否通过靶向脂肪酸代谢来钝化脂肪变性；其次，我们将剖析牛奶骨桥蛋白与脂多糖结合的能力是否会降低库普弗细胞的激活、肿瘤坏死因子的产生以及其他促炎细胞因子和氧化/亚硝化应激。慢性Lieber-DeCarli模型和葡聚糖硫酸钠或脂多糖治疗将被使用。在目标3中，将开发一种基于自噬阻断的新的酒精性肝病模型。接下来，我们将确定牛奶骨桥蛋白是否通过激活自噬途径而减少脂肪变性和肝脏损伤，而不依赖于靶向细菌易位或结合内毒素。因此，这项建议的总体目标是调查牛奶骨桥蛋白饮食是否可以成为减缓或防止酒精性肝病进展的一种有效的低成本治疗策略。 公共卫生相关性：酒精性肝病影响全球数百万人，并在许多患者中进展为酒精性脂肪性肝炎、纤维化和肝硬化。我们最近发现骨桥蛋白是一种维生素D诱导的蛋白，具有保护酒精性肝损伤的能力。本文建议的工作将评估和阐明维生素D和骨桥蛋白的保护作用发生的机制，从而有助于设计新的、可获得的、廉价的治疗方法来预防或减缓酒精性肝炎。

DESCRIPTION (provided by applicant): Alcoholic liver disease is a leading cause of liver disease and death worldwide; thus, there is an urgent need to develop novel therapeutic interventions. Key events for the onset and progression of alcoholic liver disease result from the gut-to-liver interaction. Milk osteopontin protects the gut by maintaining the epithelial barrier function, providing mucosal defense, preventing sepsis and the inflammatory response. So far, a role for milk osteopontin in protecting from alcoholic liver disease has not been established. We believe that nutritional therapy using milk osteopontin could protect from alcohol-induced liver injury. In this Application we will focus on testing the Central Hypothesis "Dietary supplementation with milk osteopontin could prevent alcoholic liver disease due to its gut protective and antisteatotic actions". In particular, we hypothesize that milk osteopontin will: 1) Target the gut-liver axis protecting the intestinal mucosal barrier and blocking the translocation of Gram-negative bacteria from the gut into the portal circulation thus lowering lipopolysaccharide levels; 2) Prevent steatosis and liver injury by targeting fatty acid metabolism and decreasing lipopolysaccharide-mediated Kupffer cell activation and TNF¿ production; and 3) Avert hepatic steatosis, inflammation and liver injury by increasing autophagy, a recently identified pathway regulating steatosis. Using models of alcohol-induced liver injury, mice will be treated with milk osteopontin to assess its therapeutic potential. To prove our hypothesis we plan three Specific Aims. In Aim 1, we will analyze if milk osteopontin blocks the ethanol-mediated increase in gut permeability, bacterial translocation and lipopolysaccharide availability. The chronic Lieber-DeCarli model along with dextran sodium sulfate treatment will be used. In Aim 2, first, we will determine whether milk osteopontin blunts steatosis by targeting fatty acid metabolism; and second, we will dissect if the ability of milk osteopontin to bind lipopolysaccharide lowers Kupffer cell activation, TNF¿ production as well as other pro-inflammatory cytokines and oxidative/nitrosative stress. The chronic Lieber-DeCarli model along with dextran sodium sulfate or lipopolysaccharide treatment will be used. In Aim 3, a new model of alcoholic liver disease based on autophagy blockade will be developed. Next, we will identify if milk osteopontin reduces steatosis and liver injury by activating the autophagy pathway independent of targeting bacterial translocation or binding lipopolysaccharide. Thus, the Overall Goal of this Proposal is to investigate whether dietary administration of milk osteopontin could be an efficient low-cost therapeutic strategy for slowing down or preventing the progression of alcoholic liver disease. PUBLIC HEALTH RELEVANCE: Alcoholic liver disease affects several million people worldwide and progresses to alcoholic steatohepatitis, fibrosis and cirrhosis in many patients. We have recently identified osteopontin as a vitamin D-inducible protein with the ability to protect from alcohol-induced liver injury. The work proposed herein will evaluate and elucidate the mechanisms by which the protective effects of vitamin D and osteopontin occur; thus, contributing to design new, accessible and inexpensive therapies to prevent or slow down alcoholic hepatitis.