IgE-guided RNAi silencing of FceRIb expression as a novel allergy therapeutic

描述（由申请人提供）：本申请的总体目标是测试IgE引导，RNA干扰（RNAi）介导，小干扰RNA （siRNA）靶向沉默IgE高亲和受体（Fc¿RIb） β链作为治疗过敏性疾病的新疗法的可行性。在过去的几十年里，过敏症越来越普遍，现在已经成为世界范围内一个主要的公共卫生问题。然而，过敏的治疗选择仍然非常有限。提出的新治疗方法是基于ige引导的RNAi策略的平台，靶向启动和/或调节过敏反应的关键基因FceRIb，以减弱嗜碱性细胞和肥大细胞的过敏反应，最终抑制过敏性疾病。为此，将靶向FceRIb表达沉默的带负电荷的siRNA分子与由抗ige Fab片段偶联到带正电荷的阳离子聚合物聚乙烯亚胺（PEI）组成的偶联物络合。因此，Fab-PEI:siRNA复合物可以非常有效地聚焦到ige结合的嗜碱性细胞/肥大细胞的细胞表面进行靶向递送。由于关键的作用，作为一个

DESCRIPTION (provided by applicant): The overall goal of this application is to test the feasibility of an IgE-guided, RNA interference (RNAi)-mediated, targeted silencing of the beta chain of the high affinity receptor for IgE (Fc¿RIb) by small interfering RNA (siRNA) as a novel therapeutic to treat allergic diseases. With increasing prevalence in the past decades, allergies have now become a major public health problem worldwide. However, the treatment options for allergies remain very limited. The proposed novel therapeutic approach is a platform based on an IgE-guided RNAi strategy, targeting the critical gene for initiation and/or regulation of the allergic response, FceRIb, to attenuate the allergic response in basophils and mast cells for ultimate suppression of allergic diseases. To this end, the negatively charged siRNA molecules targeting for FceRIb expression silencing are complexed with the conjugates composed of the anti-IgE Fab fragment coupled to the positively charged cationic polymer polyethylenimine (PEI). Therefore, the Fab-PEI:siRNA complex can be highly effective for focusing onto the cell surfaces of the IgE-bound basophils/mast cells for targeted delivery. Due to the critical role as a potent amplifier for allergic response, targeted silencing of the FceRIb in allergic effector cellsis expected to attenuate the signaling cascade, resulting in the suppression of the allergic response. Thus we hypothesized that allergic responses can be blocked by targeted silencing of the FceRIb expression in the allergic effector cells. To test this hypothesis, in Aim 1 we will develop the optimal IgE-guided RNAi approach for targeted FceRIb silencing in basophils/mast cells as a novel strategy for suppression of allergic responses in vitro in cell culture based models. We will refine and determine the optimal conditions for maximal RNAi knockdown effects on FceRIb expression in basophil/mast cells and determine the outcome of FceRIb expression silencing on inhibition of allergic response in vitro. In Aim 2, we will test the therapeutic effects of the targeted FceRIb knockdown mediated by IgE-guided RNAi to block the allergic response in three different animal models. This application will likely lead to the development of a novel siRNA-based approach for the treatment and prevention of allergic diseases.