Determining the Physiological Mechanism of CFTR Inhibition by Sphingomyelinase

项目摘要 本申请中提出的研究试图解决抑制囊性癌的生理基础。 纤维化跨膜传导调节因子（CFTR）通过鞘磷脂酶（SMase）。CFTR是 常见遗传疾病囊性纤维化（CF）中的蛋白质缺陷。目前的主要死因是 CF是由频繁的细菌感染和肺部持续炎症引起的肺功能不全。 有趣的是，感染和炎症都会促进SMase酶的分泌，我们的实验室已经证明了这一点。 降低CFTR的功能。为了了解SMase是否在CF疾病严重程度恶化中发挥作用，我们 将首先通过使用质谱和免疫组织化学定量CF肺中SMase的量。我们 然后将确定SMase抑制CFTR的机制，通过使用电生理学来研究 CFTR的行为和药理学方法来否定SMase对CFTR活性的影响。最后我们 将确定SMase介导的CFTR抑制对唯一临床批准的 CFTR增效剂药物（VX-770）。基于我们以前的发现，我们假设SMase在人乳腺癌中上调， CF肺，通过一种新的机制抑制CFTR，并阻止VX-770拯救CFTR活性。在一起， 这些数据将有助于确定CF患者是否需要联合用药以抵消SMase对 CFTR。

PROJECT SUMMARY The research proposed in this application seeks to address the physiological basis of inhibition of the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) by the enzyme sphingomyelinase (SMase). CFTR is the protein defective in the common genetic disease Cystic Fibrosis (CF). The current major cause of death for CF is pulmonary insufficiency caused by frequent bacterial infections and persistent inflammation of the lungs. Interestingly, both infection and inflammation promote secretion of the enzyme SMase, which our lab has shown to decrease the function of CFTR. To understand if SMase plays a role in worsening disease severity in CF, we will first quantify the amount of SMase in CF lungs by using mass spectrometry and immunohistochemistry. We will then determine the mechanism by which SMase inhibits CFTR by using electrophysiology to study the behavior of CFTR and pharmacological methods to negate the effects of SMase on CFTR activity. Lastly, we will determine the effect SMase-mediated inhibition of CFTR has on the efficacy of the only clinically-approved CFTR potentiator drug (VX-770). Based on our previous findings, we hypothesize that SMase is upregulated in the CF lung, inhibits CFTR via a novel mechanism, and prevents VX-770 from rescuing CFTR activity. Together, these data will help determine if CF patients need co-administration of a drug to nullify the effects of SMase on CFTR.