Molecular mechanisms and functional consequences of P2X7 purinoceptor activation

P2X7是一种核苷酸门控离子通道，主要由调节性T细胞亚群表达，在炎症中起重要作用。该项目的主要目标是阐明P2X7离子通道门控对T细胞的分子机制和功能。为此，我们已经产生了纳米抗体（来自免疫的美洲驼的单域抗体），其有效地阻断或增强细胞外核苷酸对P2X7的门控。这些纳米抗体提供了独特的工具来评估P2X7的表达，并在免疫应答期间调节P2X7在鼠和人T细胞上的功能。将使用P2X7突变体和嵌合体评价对纳米抗体结合和受体门控重要的P2X7氨基酸残基。一个转基因小鼠模型表达的过度活跃的P2X7变体，预计产生更好的理解P2X7在生理和病理免疫反应中的作用。人T细胞中P2X7表达和功能的表征预期为P2X7特异性纳米抗体的治疗应用提供基础。该项目的长期目标是将这些纳米抗体应用于改善炎症性疾病的诊断和治疗。

P2X7 is a nucleotide-gated ion channel that is prominently expressed by regulatory T cell subsets and plays an important role in inflammation. The primary goal of the proposed project is to elucidate the molecular mechanisms and functions of P2X7 ion channel gating on T cells. To this end, we have generated Nanobodies (single domain antibodies from immunized llamas) that effectively block or potentiate gating of P2X7 by extracellular nucleotides. These Nanobodies provide unique tools to assess the expression of P2X7 and to modulate the function of P2X7 on murine and human T cells during immune responses. Amino acid residues of P2X7 important for Nanobody binding and for gating of the receptor will be evaluated using P2X7 mutants and chimeras. A transgenic mouse model expressing a hyper-active P2X7-variant is expected to yield a better understanding of the role of P2X7 in physiological and pathological immune responses. Characterization of P2X7 expression and function in human T cells is expected to provide a basis for therapeutical applications of P2X7-specific Nanobodies. Long term goals of the project are to apply these Nanobodies for improved diagnostics and therapy of inflammatory diseases.