The Paracrine Regulation of Mast Cells During Biliary/Cholangiocyte Repair and Damage

胆管病，包括原发性硬化性胆管炎（PSC）是胆汁淤积性肝病，靶向 胆管细胞。PSC没有明确的治疗方法，治愈措施难以捉摸，因此翻译 研究是非常必要的。PSC以胆管反应（DR）为特征，包括增强的胆管 肿块、胆管衰老、炎症、胆管周围纤维化和门脉肥大细胞（MC）增加 存在/激活。在肝损伤期间，MC迁移到肝脏并驻留在受损/衰老的胆汁附近。 胆管和抑制胆汁来源的衰老相关分泌表型（SASP）可降低PSC 小鼠的表型。MC浸润/激活或稳定的确切来源仍不清楚。褪黑素 通过特异性受体MT 1和MT 2发挥作用，这些受体由胆管细胞表达并上调 但对肝损伤有不同的影响。MT 1的敲低降低胆汁淤积性肝损伤， 而MT 2的敲低增加胆汁淤积性肝损伤。抗炎和抗氧化特性 褪黑激素是众所周知的;然而，褪黑激素也可以抑制HA信号传导，表明这些之间的联系。 这两种分子至今仍难以找到褪黑激素信号和MC之间的一个关键因素- 组胺（HA）是alarmin，SASP，IL-33是ST 2受体（在MC上表达）的配体， IL-33/ST 2在胆汁淤积中上调。由于褪黑激素调节IL-33/ST 2信号，从而调节MC 激活/稳定，这两者之间存在着天然的联系。初步数据表明（i）IL-33/ST 2 人PSC和Mdr 2-/-小鼠中与HA含量增加相关的信号传导增加;（ii）Mdr 2-/-小鼠 用ST 2抑制剂治疗的患者具有减少的DR、炎症和IL-33含量;和（ii）褪黑激素疗法 降低MC活化和胆汁IL-33含量。这些数据支持我们的总体假设，即在肝脏 损伤，增加的全身和肝脏IL-33水平诱导MC浸润/活化驱动PSC表型， 其可以通过调节褪黑激素/MT-1信号传导来改善。SA 1假设：肝脏IL-33/ST 2 信号传导驱动MC浸润/活化和PSC表型。我们将评估（i）IL-的细胞来源 （ii）IL-33/ST 2调节对MC迁移/活化的影响 和PSC表型。SA 2假设：肝损伤和操作期间MC浸润增加IL-33 MC介导物的降低IL-33/ST 2信号传导。我们将确定（i）直接操纵MC-HA信号传导 使用培养系统和3D人类类器官改变IL-33/ST 2信号传导;（ii）MC-HA/HR信号传导的变化 在体内介导IL-33/ST 2结果和（iii）在体外操作MC是否影响PSC表型。SA3 假设：外源性褪黑激素或褪黑激素信号转导的操纵通过稳定性降低肝损伤 胆汁褪黑激素的自分泌调节可降低MC的增殖和IL-33/ST 2的下调， MC活化和IL-33/ST 2。我们将测量（i）褪黑激素治疗对PSC结果的影响;（ii）自分泌 胆汁褪黑激素对IL-33/ST 2和疾病表型的影响。

Cholangiopathies, including primary sclerosing cholangitis (PSC) are cholestatic liver diseases that target cholangiocytes. No definitive treatments for PSC exist and curative measures are elusive, thus translational studies are critically needed. PSC is characterized by ductular reaction (DR) encompassing enhanced bile duct mass, biliary senescence, inflammation, peribiliary fibrosis and increased portal mast cell (MC) presence/activation. During liver damage, MCs migrate to the liver and reside near damaged/senescent bile ducts and inhibition of biliary-derived senescent associated secretory phenotypes (SASP) reduces PSC phenotypes in mice. The exact source of MC infiltration/activation or stabilization remains unclear. Melatonin exerts its effects via specific receptors, MT1 and MT2, which are expressed by cholangiocytes and upregulated in cholestasis but have differential effects on liver damage. Knockdown of MT1 decreases cholestatic liver injury, whereas knockdown of MT2 increases cholestatic liver injury. Anti-inflammatory and anti-oxidant properties of melatonin are well-known; however, melatonin can also inhibit HA signaling, suggesting a link between these two molecules that, to date, has remained elusive. One key element between melatonin signaling and MC- histamine (HA) is the alarmin and SASP, IL-33, which is the ligand of the ST2 receptor (expressed on MCs) and IL-33/ST2 are upregulated in cholestasis. Since melatonin modulates IL-33/ST2 signaling which regulates MC activation/stabilization, there is a natural link between these two. Preliminary data demonstrates that (i) IL-33/ST2 signaling increases in human PSC and Mdr2-/- mice that correlates with increased HA content; (ii) Mdr2-/- mice treated with an ST2 inhibitor have reduced DR, inflammation and IL-33 content; and (ii) melatonin therapy decreases MC activation and biliary IL-33 content. These data support our overall hypothesis that, during liver damage, increased systemic and hepatic IL-33 levels induce MC infiltration/activation driving PSC phenotypes, which can be ameliorated via modulation of melatonin/MT-1 signaling. SA1 Hypothesis: Hepatic IL-33/ST2 signaling drives MC infiltration/activation and PSC phenotypes. We will evaluate (i) the cellular source(s) of IL- 33 using in vivo models and in vitro systems; and (ii) effects of IL-33/ST2 modulation on MC migration/activation and PSC phenotypes. SA2 Hypothesis: MCs infiltration increases IL-33 during liver damage and manipulation of MC mediators decreases IL-33/ST2 signaling. We will determine if (i) manipulation of MC-HA signaling directly alters IL-33/ST2 signaling, using cultured systems and 3D human organoids; (ii) changes in MC-HA/HR signaling in vivo mediates IL-33/ST2 outcomes and (iii) if manipulation of MCs in vitro affects PSC phenotypes. SA3 Hypothesis: Exogenous melatonin or manipulation of melatonin signaling decreases liver damage by stabilization of MCs and downregulation of IL-33/ST2 and there is an autocrine regulation of biliary melatonin that may reduce MC activation and IL-33/ST2. We will measure (i) effects of melatonin therapy on PSC outcomes; (ii) autocrine effects of biliary melatonin on IL-33/ST2 and disease phenotypes.