mTORC1/2 Signaling in the Heart in Autosomal Dominant Polycystic Kidney Disease (ADPKD)

心脏疾病是PKD患者的常见死亡原因。心血管疾病机制的研究进展 除了高血压之外，肥大是一种未满足的需求。此外，测试阻断的新型药剂 mT 0 RC 1/2输出例如第2、第3和第4代mT 0 RC 1/2抑制剂和棕榈酸酯缀合的ASO， 有力地穿透心肌，是心脏肥大以及PKD的一个未满足的需求 具体来说mTOR抑制剂领域最令人兴奋的发展是以下药物的开发： 这些化合物是高度mTORC 1特异性的，并且具有比第一代mTOR抑制剂更少的副作用。 发现DL 001在细胞和体内对mTORC 1的选择性比雷帕霉素高40倍， 雷帕霉素对糖耐量试验无影响，对血脂无影响， 对总T细胞数量有影响，对CD 3 + CD 8+（抑制/细胞毒性）T细胞无影响。我们将测试DL-001 在我们的PKD模型中这些实验挑战了先前存在的高血压是主要引发者的范式 PKD患者心脏肥大和舒张功能障碍的可能性。我们认为mTORC 1/2增加 Pkd 1 RC/RC小鼠高血压前心脏信号、心脏肥大和舒张功能障碍。 基于mTORC 1/2对心脏损害或保护机制的已知作用， 肥大，总体假设是mTORC 1引起PKD的心脏肥大，而mTORC 2引起PKD的心脏肥大。 保护性的我们提出mTORC 1（4 E-BP 1， eIF 4 E，pS 6）将改善心脏肥大，而mTORC 2的药理学或遗传学抑制（Rictor， Akt、PKCα）在心肌肥厚中起重要作用。在短期内，遗传学研究将提供 深入了解心脏中的新型mTORC 1和2信号通路。关键是要了解 心脏肥大的病理生理学，因为它与mTORC 1/2相关，以提供对 治疗心肌肥大的新疗法。从长远来看，未来小说的潜在用途 PKD中的药理学mTOR抑制剂/激活剂将在小鼠模型中进行测试， 疾病开发新的mTORC 1和2抑制剂，可能具有更好的治疗特性， 副作用比现有的mTOR抑制剂少，可能会改变未来的临床实践， 心肌肥大中的mTOR抑制剂。该提案意义重大，因为它探讨了未回答的问题， mTORC 1/2信号在心肌肥大中的作用：1）基因敲除、阿索治疗和 4 E-BP 1/eIF 4 E途径的不同组分的药理学抑制，2）新的第2、第3代 和第4代mTOR抑制剂，3）mTORC 2的药理学抑制/活化的效果。4)的 抑制mTORC 2输出、Akt或PKCα的作用。5)mTORC 1/2抑制对自噬通量的影响 6）AMPK激活剂在已经增加的p- AMPK激活。成功完成研究的目标将使人们更加关注 PKD临床前/临床研究中的心脏，PKD患者心脏功能的早期检测和临床 针对心肌肥大中的mTORC 1/2的新药物的研究以及PKD特异性。

Cardiac disease, is a common cause of death in PKD patients. Study of the mechanisms of cardiac hypertrophy, beyond hypertension, is an unmet need. Furthermore, testing of novel agents that block mTORC1/2 outputs e.g. 2nd, 3rd and 4th generation mTORC1/2 inhibitors and palmitate conjugated ASOs that vigorously penetrate heart muscle, is an unmet need in cardiac hypertrophy in general as well as PKD specifically. The most exciting development in the field of mTOR inhibitors has been the development of compounds that are highly mTORC1 specific and have less side effects than first generation mTOR inhibitors. DL001 was found to be 40 times more selective for mTORC1 than rapamycin in cells and in vivo and unlike rapamycin, had no effect on glucose tolerance test, did not affect plasma lipids, had a significantly smaller effect on total T cell numbers and no effect on CD3+CD8+ (suppressor/cytotoxic) T cells. We will test DL-001 in our PKD models. The experiments challenge the pre-existing paradigm that hypertension is the main initiator of cardiac hypertrophy and diastolic dysfunction in PKD. We propose that there is increased mTORC1/2 signaling in the heart, cardiac hypertrophy and diastolic dysfunction before hypertension in Pkd1RC/RC mice. Based on the known effects of mTORC1/2 on mechanisms that are deleterious or protective in cardiac hypertrophy, the overall hypothesis is that mTORC1 causes cardiac hypertrophy in PKD while mTORC2 is protective. We propose that genetic or pharmacological inhibition of phosphorylation of mTORC1 (4E-BP1, eIF4E, pS6) will improve cardiac hypertrophy while pharmacological or genetic inhibition of mTORC2 (Rictor, Akt, PKCα) will be harmful in cardiac hypertrophy. In the short term, the genetic studies will offer mechanistic insights into novel mTORC1 and 2 signaling pathways in the heart. It is crucial to understand the pathophysiology of cardiac hypertrophy as it relates to mTORC1/2 to provide insights into the development of new therapies to treat the cardiac hypertrophy. In the long term, the potential future use of novel pharmacological mTOR inhibitors/activators in PKD will be tested in mouse models, orthologous of the human disease. The development of novel mTORC1 and 2 inhibitors, that may have a better therapeutic profile and fewer side effects than existing mTOR inhibitors, may change future clinical practice regarding the use of mTOR inhibitors in cardiac hypertrophy. The proposal is significant as it explores unanswered questions of mTORC1/2 signaling in cardiac hypertrophy: 1) The effect of genetic knockout, ASO therapies and pharmacological inhibition of different components of the 4E-BP1/eIF4E pathway, 2) The effect of new 2nd, 3rd and 4th generation mTOR inhibitors, 3) The effect of pharmacological inhibition/activation of mTORC2. 4) The effect of inhibition of mTORC2 outputs, Akt or PKCα. 5) The effect of mTORC1/2 inhibition on autophagic flux in the heart, 6) The effect of AMPK activators to restrain mTORC1 under conditions of already increased p- AMPK activation. Successful completion of the Aims of the study will lead to more attention being paid to the heart in pre-clinical/clinical studies in PKD, earlier testing of cardiac function in PKD patients and clinical studies of novel agents that target mTORC1/2 in cardiac hypertrophy in general as well as PKD specifically.