Mechanisms of gallbladder smooth muscle dysfunction

胆囊疾病是最常见的消化系统疾病之一，其特点包括 收缩性降低、炎症和胆结石形成。三个特征始终与 胆结石疾病：（1）胆汁中胆固醇疏水盐和甘油三酯（TG）水平升高;（2） 胆囊的炎症;和（3）胆囊张力和收缩力的损害。但 胆结石形成减少、炎症和收缩性之间的相互关系尚不清楚， 这反映了我们对导致静息张力降低的细胞事件缺乏了解， 胆囊疾病中的餐后收缩。本申请旨在解决这些基本问题。 我们知识的差距。本基金申请的总体目标是：（1）阐明细胞和 胆石病中胆囊平滑肌（GBSM）收缩性被破坏的离子机制; (2)确定炎症在胆囊结石中平滑肌功能障碍和相关胆汁淤积中的作用 探讨亲水性胆盐通过预防胆囊炎， 或逆转这些对GBSM的破坏。我们将使用野生型和转基因小鼠喂养致石（胆结石） 形成）饮食，以评估在GBM和Cajal间质细胞（ICC）中发生的功能变化。 正常小鼠和未发生胆囊炎症的小鼠中胆结石疾病的进展。 我们还将评估GBSM在喂食致石饮食的小鼠中的功能，同时用环氧合酶治疗。 抑制剂或保护性亲水性胆汁盐熊去氧胆酸（UDCA）。第二种模式涉及 胆固醇和胆盐对胆囊肌层作用的体外评价 制剂，有或没有预先应用UDCA。这种方法使我们能够检查 这些化合物，单独或一起，对GBSM和ICC在受控环境。 这项拨款建议涉及一个综合的方法，使用最先进的技术来调查 胆囊病理生理学从单分子到完整组织的疾病进展过程中， 动物使用的技术包括GBSM细胞和完整肌肉中ICC的光遗传学Ca 2+成像 分别来自完整和分离的GBSM细胞的束、细胞内和膜片钳记录，以及 肌层张力测量。结合我们以前对平滑肌功能的研究，我们将 提供了胆囊运动功能如何被破坏导致胆汁淤积的见解， 运动功能紊乱与炎症之间的相互关系。此外，这些研究将阐明 UDCA预防或逆转GBSM/ICC细胞变化的治疗潜力，这些细胞变化是降低 胆囊收缩，并揭示介导其在胆囊中作用的细胞机制。

Gallbladder disease is one of the most common digestive disorders, and hallmark properties include decreased contractility, inflammation, and gallstone formation. Three features are consistently associated with gallstone disease: (1) elevated cholesterol hydrophobic salt and triglyceride (TG) levels in the bile; (2) inflammation of the gallbladder; and (3) impairments in gallbladder tone and contractility. Nevertheless, the interrelationships between decreased gallstone formation, inflammation, and contractility are not understood, and this reflects our lack of understanding of the cellular events that lead to decreased resting tone and postprandial contractions in gallbladder disease. This grant application proposes to address these fundamental gaps in our knowledge. The overall objectives of this grant application are to: (1) elucidate the cellular and ionic mechanisms by which gallbladder smooth muscle (GBSM) contractility is disrupted in gallstone disease; (2) determine the role of inflammation in smooth muscle dysfunction and associated biliary stasis in gallstone disease; and (3) explore the utility of hydrophilic bile salts in the protection of gallbladder function by preventing or reversing these disruptions to GBSM. We will use wild type and transgenic mice fed a lithogenic (gallstone forming) diet to evaluate the functional changes that occur in GBSM and interstitial cells of Cajal (ICC) during the progression of gallstone disease in normal mice and mice that do not develop gallbladder inflammation. We will also evaluate GBSM function in mice fed a lithogenic diet while being treated with a cyclooxygenase inhibitor, or the protective hydrophilic bile salt, ursodeoxycholic acid (UDCA). The second model involves evaluation of the effects of cholesterol and hydrophobic bile salts applied in vitro to gallbladder muscularis preparations, with or without prior application of UDCA. This approach allows us to examine the actions of these compounds, individually or together, on GBSM and ICC in a controlled environment. This grant proposal involves an integrated approach using state-of-the-art techniques to investigate gallbladder pathophysiology from single molecules to intact tissue during the progression of disease in the animal. Techniques to be used include optogenetic Ca2+ imaging of GBSM cells and ICC in intact muscle bundles, intracellular and patch clamp recording from intact and isolated GBSM cells, respectively, and muscularis tension measurements. Together with our previous studies on smooth muscle function, we will provide insights on how gallbladder motor function is disrupted leading to biliary stasis, and the interrelationship between disrupted motor function and inflammation. Furthermore, these studies will elucidate the therapeutic potential of UDCA to prevent or reverse cellular changes in GBSM/ICC that underlie decreased gallbladder contractility, and uncover the cellular mechanisms that mediate their actions in the gallbladder.