Mast Cell Regulation of Alcohol-Induced Liver Damage

酒精性肝损伤（ALD）包括一系列广泛的病因，患者表现为单纯性脂肪变性， 酒精性脂肪性肝炎（ASH）、酒精性肝炎、肝硬化和引起肝功能衰竭的肝细胞癌。 研究已经检查了ALD病理学对肝细胞的影响;然而，已知的信息有限 关于肥大细胞（MC）的作用以及在ALD进展过程中与胆管细胞的串扰。非酒精 脂肪肝（NAFLD），衰老的胆管细胞显示衰老相关的分泌表型 （SASP），将MC招募到肝脏，在那里它们与其他肝细胞相互作用。胆汁淤积患者， NAFLD，MC在衰老胆管周围的门静脉周围区域中大量存在。抑制 MC-组胺（HA）改善疾病表型。在接受西方饮食的MC缺陷型小鼠（KitW-sh）中， 存在NAFLD表型的消退。干细胞因子（SCF）是胆汁淤积患者中上调的SASP 在NAFLD期间受损的胆管细胞中增加。SCF与受体c-Kit（存在于 SCF/c-Kit是MC迁移的主要趋化途径。使用Vivo-1抑制肝SCF 吗啉代治疗降低了Mdr 2-/-小鼠中MC迁移和胆汁淤积性肝脏表型，并抑制了Mdr 2-/-小鼠中MC迁移和胆汁淤积性肝脏表型。 SCF在体外阻断MC向受损胆管细胞的迁移。在慢性肝炎中，MC脱粒和 HA分泌上调，SCF/c-Kit表达增加与HA呈正相关。研究 证明了MC在NAFLD和非酒精性脂肪性肝炎期间的显着作用;然而，没有研究 已经执行，以了解在ALD过程中与胆管细胞的MCs或串扰的贡献。的 我们的探索性研究的前提是建立在初步数据表明，（i）MC的存在周围 ASH患者的胆管增加;（ii）在喂食乙醇（EtOH）的小鼠中，血清HA和SCF增加;（iii）KitW-sh 喂食EtOH的小鼠具有减少的肝脂肪变性和炎症，并且（iv）在小鼠中SCF基因表达增加。 胆管细胞，但不是在肝细胞喂养乙醇。基于这些发现，我们提出了新的 假设在ALD期间，受损的胆管细胞分泌增加的SCF，其募集c-Kit阳性MC， 肝脏通过旁分泌与居民相互作用促进脂肪变性、小管反应、炎症和纤维化 肝细胞和增加的HA信号传导。为了评估我们的假设，我们提出以下具体目标： 具体目的1：证明ALD肝脏表型依赖于通过胆汁SCF的MC-HA信号传导 和MC c-Kit相互作用;和具体目的2：在啮齿动物模型中测试MC稳定剂对ALD进展的影响。 我们将使用来自ALD的人体组织和对照以及从人体细胞构建的类器官（具有 协助co-I，Dr. Burcin Ekser）沿着与慢性加过量EtOH啮齿动物模型（Bin Gao-NIAAA 在合作者Gianfranco Alpini博士的协助下，这项研究既新颖又具有探索性， 有初步的数据和可行的实验支持。如果成功，我们将为MC确定一个新的角色沿着 为ALD患者提供潜在的治疗生物标志物和治疗策略。

Alcoholic liver injury (ALD) encompasses a vast array of etiologies and patients present with simple steatosis to alcoholic steatohepatitis (ASH), alcoholic hepatitis, cirrhosis, and hepatocellular carcinoma causing liver failure. Studies have examined the effects of ALD pathology on hepatocytes; however, limited information is known about the role of mast cells (MCs) and cross-talk with cholangiocytes during ALD progression. In non-alcoholic fatty liver disease (NAFLD), senescent cholangiocytes display a senescence-associated secretory phenotype (SASP), recruiting MCs to the liver where they interact with other liver cells. In patients with cholestasis and NAFLD, MCs are found in high numbers in the periportal area surrounding senescent bile ducts. Inhibition of MC-histamine (HA) ameliorates disease phenotypes. In MC-deficient mice (KitW-sh) subjected to Western Diet, there is resolution of NAFLD phenotypes. Stem cell factor (SCF) is a SASP upregulated in cholestatic patients and increased in damaged cholangiocytes during NAFLD. SCF interacts with the receptor, c-Kit, (present on MCs), and SCF/c-Kit is a prime chemoattractant pathway for MC migration. Inhibition of hepatic SCF using Vivo- Morpholino treatment decreases MC migration and cholestatic liver phenotypes in Mdr2-/- mice, and inhibition of SCF blocks MC migration toward damaged cholangiocytes, in vitro. In chronic hepatitis, MC degranulation and HA secretion are upregulated and increased SCF/c-Kit expression positively correlates to HA. Studies have demonstrated the prominent role for MCs during NAFLD and non-alcoholic steatohepatitis; however, no studies have been performed to understand the contribution of MCs or crosstalk with cholangiocytes during ALD. The premise of our exploratory study is built on preliminary data demonstrating that (i) MC presence surrounding bile ducts increases in ASH patients; (ii) in mice fed ethanol (EtOH), serum HA and SCF increase; (iii) KitW-sh mice fed EtOH have reduced hepatic steatosis and inflammation and (iv) SCF gene expression increases in cholangiocytes, but not in hepatocytes in mice fed EtOH. Based on these findings, we propose the novel hypothesis that during ALD, damaged cholangiocytes secrete increased SCF that recruits c-Kit-positive MCs to the liver promoting steatosis, ductular reaction, inflammation and fibrosis by paracrine interactions with resident liver cells and increased HA signaling. To evaluate our hypothesis, we propose the following specific aims: Specific aim 1: To demonstrate that ALD liver phenotypes are dependent on MC-HA signaling via biliary SCF and MC c-Kit interaction; and Specific aim 2: To test MC stabilizers on the progression of ALD in rodent models. We will evaluate our aims using human tissues from ALD and control and organoids built from human cells (with assistance from co-I, Dr. Burcin Ekser) along with chronic plus binge EtOH rodent models (Bin Gao-NIAAA model) with assistance from Dr. Gianfranco Alpini, collaborator. The study is both novel and exploratory, supported by preliminary data and feasible experiments. If successful, we will identify a new role for MCs along with potential therapeutic biomarkers and treatment strategies for those suffering from ALD.