Development of Modified Caveolin-1 Scaffolding Domain Peptides with Improved Pharmacological Properties as Therapeutic Agents for Scleroderma Skin Disease

摘要我们的长期目标是开发一种有效的治疗硬皮病（系统性硬化症， SSc）皮肤纤维化。Caveolin-1是一个很有前途的纤维化疾病治疗靶点。的促纤维化作用 细胞和小鼠模型中的小窝蛋白-1缺陷被与其活性位点等同的肽抑制 （小窝蛋白-1支架结构域，CSD）。然而，CSD缺乏合适的药物药理学性质， 发展为了克服这个问题，我们开发了新的，修改版本的CSD。我们首先将CSD 三个亚区，发现所有三个抑制博莱霉素诱导的皮肤纤维化。为了改善， 药理学性质，然后我们修改CSD和每个亚区是水溶性的， 蛋白水解这种修饰大大增强了细胞对所有四种修饰肽的摄取， 大大增加了它们在体外抑制几种纯化激酶的能力。到目前为止，我们只测试了其中一个 四种修饰的肽在体内，它在抑制博来霉素诱导的皮肤纤维化方面具有突出的活性， 以及相关的皮内脂肪层损失（脂肪萎缩）。这些初步研究证明， 突出支持我们的建议，从四个候选人中确定一个铅化合物，然后 评估其治疗指数（毒性和有益剂量之间的比率）。我们的研究和文献也 表明我们的肽将比FDA的重磅炸弹更有效，副作用更少- 批准的药物吡非尼酮（品牌名称Esbriet）。总之，为了进行药物开发，我们必须 识别先导化合物。由于它们在药理和功能上的差异，我们必须做一个侧面- 我们的四种修饰肽的并排比较。1)使用两个模型系统选择先导化合物： 全身博来霉素治疗和皮下注射TGF β。我们将确定一种先导化合物，然后 通过将其与对照肽（乱序Lead）和尼达尼布进行比较，证明其特异性和活性。 肽将皮下递送。在治疗方案中，在诱导纤维化后一周开始。初级 结果是皮肤纤维化和脂肪萎缩。二级读数将是以下各项的标记物水平： 肌成纤维细胞、脂肪细胞和炎性细胞。成功将被定义为> 50%的逆转。 博来霉素和TGF β对初级和次级读数的有害影响。2)确定 先导化合物的治疗指数。铅的有益作用的剂量依赖性 将使用高于和低于我们当前标准剂量的剂量确定化合物。的毒性 先导化合物将在单次治疗最大耐受剂量（MTD）实验中进行评价， 1X、5X、25 X和125 X我们当前的标准剂量。我们会认为这些研究是成功的，如果 治疗指数> 50。总之，这些研究将提供一种新的先导化合物， 成功标准，包括抑制皮肤病和安全性。

Abstract Our long-term objective is to develop an effective treatment for scleroderma (systemic sclerosis, SSc) skin fibrosis. Caveolin-1 is a promising therapeutic target in fibrotic diseases. The profibrotic effects of caveolin-1 deficiency in cells and in mouse models is suppressed by a peptide equivalent to its active site (caveolin-1 scaffolding domain, CSD). However, CSD lacks suitable pharmacologic properties for drug development. To overcome this problem, we developed novel, modified versions of CSD. We first divided CSD into three subregions and found that all three suppressed bleomycin-induced skin fibrosis. To improve, the pharmacological properties, we then modified CSD and each subregion to be water soluble and protected from proteolysis. This modification greatly enhanced the uptake by cells of all four modified peptides and also greatly increased their ability to inhibit several purified kinases in vitro. We have so far tested only one of the four modified peptides in vivo and it was outstandingly active in inhibiting bleomycin-induced dermal fibrosis as well as the associated loss of the intradermal adipose layer (lipoatrophy). These initial studies justify and outstandingly support our proposal to identify a Lead Compound from among the four candidates, then evaluate its Therapeutic Index (ratio between toxic and beneficial doses). Our studies and the literature also suggest that our peptides will be more effective and have fewer side effects than the blockbuster FDA- approved drug pirfenidone (brand name Esbriet). In summary, to proceed with drug development we must identify a Lead Compound. Due to their distinct pharmacological and functional differences, we must do a side- by-side comparison of our four modified peptides. 1) Select a Lead Compound using two model systems: Systemic Bleomycin Treatment and Subcutaneous TGFβ Injection. We will identify a Lead Compound, then demonstrate its specificity and activity by comparing it to a control peptide (scrambled Lead) and to nintedanib. Peptides will be delivered s.c. in a Therapeutic Protocol, beginning one week after fibrosis is induced. Primary Readouts will be dermal fibrosis and lipoatrophy. Secondary Readouts will be the levels of markers for myofibroblasts, adipocytes, and inflammatory cells. Success will be defined as >50% reversal of the deleterious effects of bleomycin and TGFβ on the Primary and Secondary Readouts. 2) Determine the Therapeutic Index of the Lead Compound. The dose-dependence of the beneficial effects of the Lead Compound will be determined using doses above and below our current standard dose. The toxicity of the Lead Compound will be evaluated in a Single-Treatment Maximum Tolerated Dose (MTD) Experiment using 1X, 5X, 25X, and 125X our current standard dose. We will consider these studies to be a success if the Therapeutic Index is >50. In summary, these studies will provide a novel Lead Compound that meets our Criteria for Success, both in terms of suppression of skin disease and of safety.