PDF(Pubmed)
Abstract：
UNASSIGNED: P2X receptors are a family of homo- and heterotrimeric cation channels gated by extracellular ATP. The P2X4 and P2X7 subunits show overlapping expression patterns and have been involved in similar physiological processes, such as pain and inflammation as well as various immune cell functions. While formation of P2X2/P2X3 heterotrimers produces a distinct pharmacological phenotype and has been well established, functional identification of a P2X4/P2X7 heteromer has been difficult and evidence for and against a physical association has been found. Most of this evidence stems, however, from in vitro model systems.
UNASSIGNED: Here, we used a P2X7-EGFP BAC transgenic mouse model as well as P2X4 and P2X7 knock-out mice to re-investigate a P2X4-P2X7 interaction in mouse lung by biochemical and immunohistochemical experiments as well as quantitative expression analysis.
UNASSIGNED: No detectable amounts of P2X4 could be co-purified from mouse lung via P2X7-EGFP. In agreement with these findings, immuno-histochemical analysis using a P2X7-specific nanobody revealed only limited overlap in the cellular and subcellular localizations of P2X4 and P2X7 in both the native lung tissue and primary cells. Comparison of P2X4 and P2X7 transcript and protein levels in the respective gene-deficient and wild type mice showed no mutual interrelation between their expression levels in whole lungs. However, a significantly reduced P2rx7 expression was found in alveolar macrophages of P2rx4 -/- mice.
UNASSIGNED: In summary, our detailed analysis of the cellular and subcellular P2X4 and P2X7 localization and expression does not support a physiologically relevant direct association of P2X4 and P2X7 subunits or receptors in vivo.
UNASSIGNED: Here, we used a P2X7-EGFP BAC transgenic mouse model as well as P2X4 and P2X7 knock-out mice to re-investigate a P2X4-P2X7 interaction in mouse lung by biochemical and immunohistochemical experiments as well as quantitative expression analysis.
UNASSIGNED: No detectable amounts of P2X4 could be co-purified from mouse lung via P2X7-EGFP. In agreement with these findings, immuno-histochemical analysis using a P2X7-specific nanobody revealed only limited overlap in the cellular and subcellular localizations of P2X4 and P2X7 in both the native lung tissue and primary cells. Comparison of P2X4 and P2X7 transcript and protein levels in the respective gene-deficient and wild type mice showed no mutual interrelation between their expression levels in whole lungs. However, a significantly reduced P2rx7 expression was found in alveolar macrophages of P2rx4 -/- mice.
UNASSIGNED: In summary, our detailed analysis of the cellular and subcellular P2X4 and P2X7 localization and expression does not support a physiologically relevant direct association of P2X4 and P2X7 subunits or receptors in vivo.
摘要：
■P2X受体是由细胞外ATP门控的同源和异源三聚体阳离子通道家族。P2X4和P2X7亚基显示出重叠的表达模式，并参与了类似的生理过程，如疼痛和炎症以及各种免疫细胞功能。虽然P2X2/P2X3异源三聚体的形成产生了独特的药理学表型并且已经很好地建立,P2X4/P2X7异聚体的功能鉴定很困难，并且已经发现了支持和反对物理关联的证据。大部分证据都源于此，然而,来自体外模型系统。
■这里，我们使用P2X7-EGFPBAC转基因小鼠模型以及P2X4和P2X7敲除小鼠,通过生化和免疫组织化学实验以及定量表达分析,重新研究小鼠肺中P2X4-P2X7的相互作用.
■没有可检测量的P2X4可以通过P2X7-EGFP从小鼠肺共纯化。与这些发现一致，使用P2X7特异性纳米抗体的免疫组织化学分析显示，在天然肺组织和原代细胞中，P2X4和P2X7的细胞和亚细胞定位仅有有限的重叠。各基因缺陷型和野生型小鼠中P2X4和P2X7转录物和蛋白质水平的比较显示它们在整个肺中的表达水平之间没有相互关系。然而,P2rx4-/-小鼠肺泡巨噬细胞中P2rx7的表达显著降低。
■总之，我们对细胞和亚细胞P2X4和P2X7定位和表达的详细分析不支持P2X4和P2X7亚基或受体在体内的生理相关直接关联.
■这里，我们使用P2X7-EGFPBAC转基因小鼠模型以及P2X4和P2X7敲除小鼠,通过生化和免疫组织化学实验以及定量表达分析,重新研究小鼠肺中P2X4-P2X7的相互作用.
■没有可检测量的P2X4可以通过P2X7-EGFP从小鼠肺共纯化。与这些发现一致，使用P2X7特异性纳米抗体的免疫组织化学分析显示，在天然肺组织和原代细胞中，P2X4和P2X7的细胞和亚细胞定位仅有有限的重叠。各基因缺陷型和野生型小鼠中P2X4和P2X7转录物和蛋白质水平的比较显示它们在整个肺中的表达水平之间没有相互关系。然而,P2rx4-/-小鼠肺泡巨噬细胞中P2rx7的表达显著降低。
■总之，我们对细胞和亚细胞P2X4和P2X7定位和表达的详细分析不支持P2X4和P2X7亚基或受体在体内的生理相关直接关联.
