División de Biología Molecular, Instituto Potosino Investigación Científica y Tecnológica, San Luis Potosí, SLP, México.
Catedras CONACYT, Departamento de Medicina, Centro de Ciencias de la Salud, Universidad Autónoma de Aguascalientes, Aguascalientes, México.
Eur J Pharmacol. 2020 Dec 5;888:173460. doi: 10.1016/j.ejphar.2020.173460. Epub 2020 Aug 14.
This study sought to examine the co-expression of the following purinergic receptor subunits: P2X1, P2X1del, P2X4, and P2X7 and characterize the P2X response in human monocyte-derived macrophages (MDMs). Single-cell RT-PCR shows the presence of P2X1, P2X1del, P2X4, and P2X7 mRNA in 40%, 5%, 20%, and 90% of human MDMs, respectively. Of the studied human MDMs, 25% co-expressed P2X1 and P2X7 mRNA; 5% co-expressed P2X4 and P2X7; and 15% co-expressed P2X1, P2X4, and P2X7 mRNA. In whole-cell patch clamp recordings of human MDMs, rapid application of ATP (0.01 mM) evoked fast current activation and two different desensitization kinetics: 1. a rapid desensitizing current antagonized by PPADS (1 μM), reminiscent of the P2X1 receptor's current; 2. a slow desensitizing current, insensitive to PPADS but potentiated by ivermectin (3 μM), similar to the P2X4 receptor's current. Application of 5 mM ATP induced three current modalities: 1. slow current activation with no desensitization, similar to the P2X7 receptor current, present in 69% of human macrophages and antagonized by A-804598 (0.1 μM); 2. fast current activation and fast desensitization, present in 15% of human MDMs; 3. fast activation current followed by biphasic desensitization, observed in 15% of human MDMs. Both rapid and biphasic desensitization kinetics resemble those observed for the recombinant human P2X1 receptor expressed in oocytes. These data demonstrate, for the first time, the co-expression of P2X1, P2X4, and P2X7 transcripts and confirm the presence of functional P2X1, P2X4, and P2X7 receptors in human macrophages.
P2X1、P2X1del、P2X4 和 P2X7,并表征人单核细胞衍生巨噬细胞(MDM)中的 P2X 反应。单细胞 RT-PCR 显示,在 40%、5%、20%和 90%的人 MDM 中分别存在 P2X1、P2X1del、P2X4 和 P2X7 mRNA。在所研究的人 MDM 中,25%共表达 P2X1 和 P2X7 mRNA;5%共表达 P2X4 和 P2X7;15%共表达 P2X1、P2X4 和 P2X7 mRNA。在人 MDM 的全细胞膜片钳记录中,快速应用 ATP(0.01 mM)可诱发快速电流激活和两种不同的脱敏动力学:1. 快速脱敏电流被 PPADS(1 μM)拮抗,类似于 P2X1 受体的电流;2. 缓慢脱敏电流,对 PPADS 不敏感,但被伊维菌素(3 μM)增强,类似于 P2X4 受体的电流。应用 5 mM ATP 诱导三种电流模式:1. 无脱敏的缓慢电流激活,类似于 P2X7 受体电流,存在于 69%的人巨噬细胞中,被 A-804598(0.1 μM)拮抗;2. 快速电流激活和快速脱敏,存在于 15%的人 MDM 中;3. 快速激活电流后双相脱敏,见于 15%的人 MDM 中。快速和双相脱敏动力学均类似于在卵母细胞中表达的重组人 P2X1 受体观察到的动力学。这些数据首次证明了 P2X1、P2X4 和 P2X7 转录本的共表达,并证实了功能性 P2X1、P2X4 和 P2X7 受体在人巨噬细胞中的存在。