SsnB, a Chinese herb-derived selective TLR antagonist

描述(申请人提供)：Toll样受体(TLRs)是先天免疫的关键组成部分；它们是抵御入侵病原体(如细菌和病毒)的第一道防线。由TLRS发起的信号是一把双刃剑。一方面，它可能导致限制或消灭入侵的有机体；另一方面，长期和夸大的反应可能会导致组织和器官损伤。此外，由外源性或内源性配体触发的TLR信号转导通路参与了许多慢性炎症性疾病的发病过程。例如，TLR2和TLR4与动脉粥样硬化、自身免疫性结肠炎、系统性红斑狼疮、糖尿病和阿尔茨海默病有关。因此，阻断过多的TLR信号是治疗这些疾病的一种方法。然而，目前还没有批准的TLR拮抗剂用于临床。三棱是一种中草药，长期以来一直被用来治疗几种炎症性疾病。虽然已经对这种草药的提取物做了很多工作，但还没有对其成分进行深入的分子研究。最近，为了从三尖杉块茎中分离和鉴定单一化合物，我们鉴定了一个新的化合物，玄参素B(SSnB)，它选择性地阻断TLR2和TLR4介导的信号转导。这项R21计划旨在继续这一令人兴奋的发展研究。中心假说是，SSNB可以通过选择性抑制TLR2和TLR4信号通路而被开发为抗炎药。为了检验这一假设，我们提出了两个具体目标。SA1.评价丹参皂苷B的毒性和体内抗炎作用。我们将首先评估SSNB的体内毒性，然后在内毒素血症和脓毒症小鼠模型上检测SSNB是否具有抑制炎症反应的作用。SA2.进一步阐明SSNB阻断TLR2和TLR4信号转导的分子机制。我们将确定SSNB在TLR2和TLR4信号通路上的作用部位。这些研究将为三棱块茎在炎症性疾病中的治疗效果提供机械性见解，将一种数百年来的替代疗法转化为现代药理学。SsnB作为TLR2和TLR4拮抗剂的鉴定和确认将为开发新的抗炎药提供机会。在未来的研究中，我们将测试SSNB对几种免疫相关慢性炎症性疾病的治疗价值，如动脉粥样硬化和糖尿病。 与公共卫生相关：慢性炎症性疾病的治疗需求尚未得到满足。我们鉴定了一种中草药衍生的小分子化合物SSNB，它具有选择性的TLR2和TLR4阻断活性。分子机制的阐明和体内抗炎活性的确认将使SSnB成为一种选择性的TLR2和TLR4拮抗剂和抗炎药。

DESCRIPTION (provided by applicant): Toll-like receptors (TLRs) are key components of innate immunity; they serve as the first line of defense against invading pathogens such as bacteria and viruses. The signaling initiated by TLRs is a double- edged sword. On the one hand, it may lead to confining or eliminating the invading organisms; on the other hand, a prolonged and exaggerated response can cause tissue and organ damage. Moreover, TLR signaling triggered by exogenous or endogenous ligands contributes to the pathogenesis of many chronic inflammatory diseases. For example, TLR2 and TLR4 are involved in atherosclerosis, autoimmune colitis, SLE, diabetes and Alzheimer's disease. Therefore, blockade of excessive TLR signaling is a therapeutic approach being pursued for these diseases. However, currently there are no approved TLR antagonists for clinic use. A Chinese herb, Sparganium stoloniferum has long been used in Traditional Chinese Medicine (TCM) for the treatment of several inflammatory diseases. Although much work has been done with extracts from this herb, no in-depth molecular investigation of its components has been performed. Recently, in an effort to isolate and functionally characterize single compounds from Sparganium stoloniferum tubers, we identified a novel compound, Sparstolonin B (SsnB) that selectively blocks TLR2- and TLR4-mediated signaling. This R21 proposal is aimed at continuing this exciting developmental research. The central hypothesis is that SsnB can be developed as an anti-inflammatory agent by virtue of its selective inhibitory effects on TLR2 and TLR4 signaling. To test this hypothesis, we propose two specific aims. SA1. To evaluate the toxicity and the anti- inflammatory efficacy of SsnB in vivo. We will first evaluate the in vivo toxicity of SsnB and then test if SsnB can suppress the inflammatory responses in endotoxemia and sepsis mouse models. SA2. To further elucidate the molecular mechanism by which SsnB blocks TLR2 and TLR4 signaling. We will identify the acting sites of SsnB on TLR2 and TLR4 signaling pathways. These studies will provide mechanistic insights into the therapeutic effects of Sparganium stoloniferum tubers in inflammatory diseases, translating a centuries-old alternative therapy modality into modern pharmacology. The identification and confirmation of SsnB as a TLR2 and TLR4 antagonist will provide an opportunity to develop a new anti-inflammatory agent. In future studies, we will test the therapeutic value of SsnB for several immune-related chronic inflammatory diseases such as atherosclerosis and diabetes. PUBLIC HEALTH RELEVANCE: There is an unmet need for the treatment of chronic inflammatory diseases. We have identified a Chinese herb-derived small molecule compound, SsnB, with selective TLR2 and TLR4 blocking activities. Elucidation of the molecular mechanism and confirmation of the in vivo anti-inflammatory activity will lead to the development of SsnB into a selective TLR2 and TLR4 antagonist and an anti-inflammatory agent.