Peptide-based nanoparticle inhibition of CCR3-mediated inflammatory cell recruitm

描述（由申请人提供）：趋化因子信号传导通过激活嗜酸性粒细胞、Th 2淋巴细胞、嗜碱性粒细胞和中性粒细胞迁移和募集到肺中在哮喘发病机制中起关键作用。最近的研究表明，在正确诊断的嗜酸性粒细胞哮喘患者中靶向嗜酸性粒细胞可以提供显着的健康益处。然而，患有非嗜酸性粒细胞内型哮喘的患者表现出更普遍的嗜酸性粒细胞炎症，但目前还没有针对这种内型的成功治疗。越来越多的人认识到，为了有效地干扰哮喘中炎性细胞的趋化性，需要抑制一种以上的趋化因子受体。目前，没有药物能够多方面干扰嗜酸性粒细胞和中性粒细胞的化学吸引。CCR 3趋化因子受体结合其优选的趋化因子，嗜酸性粒细胞趋化因子，并促进嗜酸性粒细胞向肺的募集。除了嗜酸性粒细胞趋化因子，CCR 3还结合负责Th 2淋巴细胞、嗜碱性粒细胞、肥大细胞和嗜中性粒细胞的趋化性的趋化因子。这种结合由受体的细胞外环介导。我们提出设计具有CCR 3细胞外环呈递的新型基于肽的纳米颗粒，以充当诱饵CCR 3受体或直接抑制受体功能。这些纳米颗粒将螯合靶向嗜酸性粒细胞和潜在的其他炎症细胞如嗜中性粒细胞的趋化因子。与通常用于药物递送的纳米级被动载体不同，我们的新型CCR 3纳米颗粒本身将充当药物。我们使用这种方法来开发基于肽的纳米颗粒，拮抗CXCR 4，一种类似于CCR 3的趋化因子受体。X4-2-6是一种跨膜螺旋肽类似物，包括胞外环1，靶向CXCR 4受体，用于抑制HIV进入和乳腺癌转移。基于x4-2-6组装成纳米颗粒并螯合SDF-1的能力，我们类似地提出开发含有CCR 3的跨膜和细胞外环部分的肽。这些肽序列由具有高螺旋倾向的疏水性氨基酸组成，并包括N-和C-末端电荷。这些肽性质是肽在水溶液中组装成球形纳米颗粒的原因。我们假设可以设计CCR 3的肽类似物，其将显示与CXCR 4肽x4-2-6类似的性质，即它们将能够形成纳米颗粒并螯合参与嗜酸性粒细胞和可能的嗜中性粒细胞迁移/募集到组织中的趋化因子（即嗜酸细胞活化趋化因子）或直接抑制CCR 3功能。为了解决这一假设，提出了两个具体的目标：（1）确定CCR 3跨膜肽组装成纳米颗粒和螯合参与嗜酸性粒细胞和中性粒细胞募集的趋化因子的能力;和（2）证明CCR 3肽纳米颗粒在小鼠三抗原过敏性哮喘模型中体外和体内抑制趋化因子依赖性炎症反应的能力。拟议的项目很可能会显着影响新的哮喘治疗方法的发展的一般方法。

DESCRIPTION (provided by applicant): Chemokine signaling plays a critical role in the pathogenesis of asthma through the activation of eosinophil, Th2 lymphocyte, basophil, and neutrophil migration and recruitment into the lung. Recent studies indicate that targeting eosinophils in patients with properly diagnosed eosinophilic asthma can provide a significant health benefits. However, patients with the non-eosinophilic endotype of asthma exhibit more prevalent neutrophilic inflammation, but there are currently no successful treatments for this endotype. There is a growing realization that to efficiently interfere with the chemotaxis of inflammatory cells in asthma, more than one chemokine receptor needs to be inhibited. Currently, there are no drugs capable of multi-faceted interference with chemoattraction of eosinophils and neutrophils. The CCR3 chemokine receptor binds its preferred chemokines, the eotaxins, and facilitates recruitment of eosinophils to the lungs. In addition to eotaxins, CCR3 also binds chemokines responsible for the chemotaxis of Th2 lymphocytes, basophils, mast cells and neutrophils. This binding is mediated by the receptor's extracellular loops. We propose to design novel peptide- based nanoparticles with CCR3 extracellular loop presentation to act as decoy CCR3 receptors or to directly inhibit receptor function. These nanoparticles would sequester chemokines that target both eosinophils and potentially other inflammatory cells such as neutrophils. Unlike commonly available nanoscale passive carriers used for drug delivery, our novel CCR3 nanoparticles will act as drugs themselves. We used this approach to develop peptide-based nanoparticles that antagonize CXCR4, a chemokine receptor similar to CCR3. X4-2-6, a transmembrane helical peptide analog that includes the extracellular loop 1, targets CXCR4 receptors for inhibition of HIV entry and breast cancer metastasis. Based on the ability of x4-2-6 to assemble into nanoparticles, and to sequester SDF-1, we similarly propose to develop peptides containing transmembrane and extracellular loop portions of CCR3. These peptide sequences consist of hydrophobic amino acids with a high helical propensity and include N- and C-terminal charges. These peptide properties are responsible for the peptide's assembly into spherical nanoparticles in aqueous solution. We hypothesize that peptide analogs of CCR3 can be designed that will display properties similar to the CXCR4 peptide x4-2-6, namely, they will be able to form nanoparticles and sequester chemokines (i.e. eotaxins) that are involved in eosinophil and possibly neutrophil migration/recruitment into tissues or directly inhibit CCR3 function. To address this hypothesis, two specific aims are proposed: (1) Determine the ability of CCR3 transmembrane peptides to assemble into nanoparticles and to sequester chemokines involved in eosinophil and neutrophil recruitment; and (2) Demonstrate the ability of CCR3 peptide nanoparticles to inhibit chemokine-dependent inflammatory responses in vitro and in vivo in the mouse triple antigen allergic asthma model. The proposed project is highly likely to significantly impact the general approach to the development of novel asthma therapeutics.