Regulation of immune reactions by synthetic thioglucans

描述（由申请人提供）：本提案的主要目标是开发，表征和测试天然免疫调节剂2-葡聚糖的新合成版本。用于预防和/或治疗疾病的天然产物已经被研究了很长时间。尽管有希望的临床试验和缺乏对其机制的了解，但热情却减弱了。天然葡聚糖是大分子，对CR3的亲和力较低，并且具有不良的副作用，因为它们的大尺寸使它们能够交联CR3，刺激促炎细胞因子的强烈释放。不幸的是，还不可能以可重复的方式产生天然2-葡聚糖的小片段。葡聚糖的作用机制从未完全确定。我们项目的新目标包括：1)合成新的、从未测试过的硫葡聚糖；2)细胞因子刺激的综合评价；3)了解吸收机制，为临床提供口服治疗；4)基因组评价。目的：设计和合成一类新的低聚糖。主要目标是优化寡聚-2-(1,3)-葡聚糖的化学结构，通过：1)提高低聚葡聚糖的稳定性，从而增加免疫刺激剂与其受体相互作用的概率；2)诱导葡聚糖与其受体之间更好的分子相互作用。目的2确定小合成硫葡聚糖的生物学特性。这一目标将通过以下四种方法实现：1)评估它们与CR3和Dectin-1受体的结合；2)测定其对13种不同细胞因子的诱导作用；3)评价口服葡聚糖的吸收和组织分布；4)利用微阵列技术比较葡聚糖处理和未处理细胞的基因表达谱，并评估可能的信号通路。来自拟建项目的数据将为定量新型硫葡聚糖的结构与其对免疫反应的影响之间的相关性提供重要的理解，以及葡聚糖影响细胞的机制的重要新信息。因此，这个项目可能会导致新的肿瘤治疗方法。公共卫生相关性：b-葡聚糖是一种众所周知的生物反应调节剂，自1980年以来，主要在日本被用作癌症的辅助治疗。b-葡聚糖还能增强宿主对某些细菌、酵母菌和病毒病原体的先天防御。此外，葡聚糖被认为是重要的预防辐照。总之，b-葡聚糖可能是最重要的天然免疫调节剂。本课题拟以葡聚糖为原料制备改性的合成低聚糖，并对其生物学特性进行表征。根据我们的初步数据，我们假设这些低聚糖将更具活性，并将克服天然b-葡聚糖的内在问题，这些问题使它们成为不受欢迎的药物。

DESCRIPTION (provided by applicant): The major objective of this proposal is to develop, characterize and test new, synthetic version of a natural immunomodulator 2-glucan. Natural products useful in preventing and/or treating disease have been studied for a long time. Despite promising clinical trials and lack of understanding of their mechanism dampened enthusiasm. Natural glucans are large molecules with a low affinity for CR3 and have undesirable side effects because their large size enables them to cross-link CR3, stimulating a strong release of proinflammatory cytokines. Unfortunately, it has not been possible to generate small fragments of natural 2- glucan in a reproducible manner. The mechanisms of glucan actions were never fully established. The novel aims of our project involve: 1) synthesis of new, never before tested thioglucans; 2) comprehensive evaluation of cytokine stimulation; 3) the understanding of the absorption mechanisms leading to oral treatment for clinical practice; 4) evaluation of genomic. Aim #1 To design and synthesize new class of oligosaccharides. Main goal is to optimize chemical structures of oligo-2-(1,3)-glucans in order to improve stimulation of the immune system by: 1) increasing stability of oligoglucans, so that the probability of interactions between the immunostimulating agent and its receptor also increases; and 2) inducing better molecular interactions between glucans and their receptors present on immunocompetent cells. Aim #2 Determine the biological characteristics of small synthetic thioglucans. This goal will be achieved using four approaches: 1) evaluate their binding to the CR3 and Dectin-1 receptor; 2) determine their effects on induction of 13 different cytokines; 3) evaluation of the absorption and tissue distribution of orally administered glucans; and 4) comparing gene expression profiles between glucan-treated and untreated cells using microarray technology and evaluation of possible signaling pathways. Data from the proposed project will provide crucial understanding of the correlation between structure of quantitatively novel thioglucans and their effects on immune reactions, as well as important new information on the mechanisms by which glucans affect the cells. This project thus may lead to the new tumor therapy. PUBLIC HEALTH RELEVANCE: b-Glucan is a well-known biological response modifier that has been used as adjuvant therapy for cancer since 1980, mostly in Japan. b-Glucans also enhance innate host defense against certain bacteria, yeast, and viral pathogens. In addition, glucans are considered to be important prophylaxis against irradiation. In summary, b-glucan might be the most important natural immunomodulator. In this project, we propose to prepare improved synthetic oligosaccharides based on glucans and to characterize their biological properties. Based on our preliminary data, we hypothesize that these oligosaccharides will be more active and will overcome intrinsic problems with natural b-glucans that make them undesirable as drugs.