How Structural Biology Has Directly Impacted Our Understanding of P2X Receptor Function and Gating

Mansoor, Steven

doi:10.1007/978-1-0716-2384-8_1

Cited by 13 publications

(6 citation statements)

References 81 publications

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“…In addition, our extensive all-atom molecular dynamics simulations have shown that the most common binding pose of diclofenac at hP2X3R largely overlaps with ATP bound to the open-state conformation of hP2X3R. Furthermore, we show by RMSF analysis that diclofenac when bound to hP2X3R alters the conformational flexibility of the left flipper and dorsal fin domains, crucially implicated in the ATP-induced gating of hP2X3R ( Mansoor et al, 2016 ; Mansoor, 2022 ). Our simulation results also offer a mechanistic explanation for the inhibition of the ATP-induced gating of hP2X3R; the strong interactions of diclofenac with the residues K201 and E270 of the dorsal fin and left flipper domains, respectively, are likely to prevent the conformational rearrangements of the dorsal fin and left flipper domains.…”

Section: Discussionmentioning

confidence: 67%

Diclofenac and other non-steroidal anti-inflammatory drugs (NSAIDs) are competitive antagonists of the human P2X3 receptor

et al. 2023

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Introduction: The P2X3 receptor (P2X3R), an ATP-gated non-selective cation channel of the P2X receptor family, is expressed in sensory neurons and involved in nociception. P2X3R inhibition was shown to reduce chronic and neuropathic pain. In a previous screening of 2000 approved drugs, natural products, and bioactive substances, various non-steroidal anti-inflammatory drugs (NSAIDs) were found to inhibit P2X3R-mediated currents.Methods: To investigate whether the inhibition of P2X receptors contributes to the analgesic effect of NSAIDs, we characterized the potency and selectivity of various NSAIDs at P2X3R and other P2XR subtypes using two-electrode voltage clamp electrophysiology.Results: We identified diclofenac as a hP2X3R and hP2X2/3R antagonist with micromolar potency (with IC50 values of 138.2 and 76.7 µM, respectively). A weaker inhibition of hP2X1R, hP2X4R, and hP2X7R by diclofenac was determined. Flufenamic acid (FFA) inhibited hP2X3R, rP2X3R, and hP2X7R (IC50 values of 221 µM, 264.1 µM, and ∼900 µM, respectively), calling into question its use as a non-selective ion channel blocker, when P2XR-mediated currents are under study. Inhibition of hP2X3R or hP2X2/3R by diclofenac could be overcome by prolonged ATP application or increasing concentrations of the agonist α,β-meATP, respectively, indicating competition of diclofenac and the agonists. Molecular dynamics simulation showed that diclofenac largely overlaps with ATP bound to the open state of the hP2X3R. Our results suggest a competitive antagonism through which diclofenac, by interacting with residues of the ATP-binding site, left flipper, and dorsal fin domains, inhibits the gating of P2X3R by conformational fixation of the left flipper and dorsal fin domains. In summary, we demonstrate the inhibition of the human P2X3 receptor by various NSAIDs. Diclofenac proved to be the most effective antagonist with a strong inhibition of hP2X3R and hP2X2/3R and a weaker inhibition of hP2X1R, hP2X4R, and hP2X7R.Discussion: Considering their involvement in nociception, inhibition of hP2X3R and hP2X2/3R by micromolar concentrations of diclofenac, which are rarely reached in the therapeutic range, may play a minor role in analgesia compared to the high-potency cyclooxygenase inhibition but may explain the known side effect of taste disturbances caused by diclofenac.

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Section: Discussionmentioning

confidence: 67%

Diclofenac and other non-steroidal anti-inflammatory drugs (NSAIDs) are competitive antagonists of the human P2X3 receptor

et al. 2023

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“…In addition, our extensive all atom molecular dynamics simulation studies have determined that the most common binding pose of diclofenac at the hP2X3R largely overlaps with ATP bound to the open-state conformation of the hP2X3R. Furthermore, we show by RMSF analysis that diclofenac when bound to the hP2X3R restricts the conformational flexibility of the left flipper and dorsal fin domains, crucially implicated in ATP-induced gating of the hP2X3R (Mansoor, 2022, Mansoor et al, 2016). Our molecular dynamics simulation results also provide a mechanistic explanation for the inhibition of the ATP-induced gating of the hP2X3R: the strong interactions of diclofenac with the residues K201 and E270 of the dorsal fin and left flipper domains, respectively, prevent the conformational rearrangements of dorsal fin and left flipper domains.…”

Section: Discussionmentioning

confidence: 79%

Diclofenac and other Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are Competitive Antagonists of the human P2X3 Receptor

Grohs

Cheng

Coenen

et al. 2022

Preprint

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The P2X3 receptor (P2X3R), an ATP-gated non-selective cation channel of the P2X receptor family, is expressed in sensory neurons and involved in nociception. P2X3R inhibition was shown to reduce chronic and neuropathic pain. In a previous screening of 2000 approved drugs, natural products and bioactive substances, various non-steroidal anti-inflammatory drugs (NSAIDs) were found to inhibit P2X3R-mediated currents. To investigate whether the inhibition of P2X receptors contributes to the analgesic effect of NSAIDs, we characterized the potency and selectivity of various NSAIDs at P2X3R and other P2XR subtypes using two-electrode voltage clamp electrophysiology. We identified diclofenac as a hP2X3R and hP2X2/3R antagonist with micromolar potency (with IC50 values of 138.2 micro M and 76.7 micro M, respectively). A weaker inhibition of hP2X1R, hP2X4R and hP2X7R by diclofenac was determined. Flufenamic acid (FFA) proved to inhibit hP2X3R, rP2X3R and hP2X7R (IC50 values of 221 micro M, 264.1 micro M and ~ 900 micro M, respectively), questioning its widespread use as a nonselective ion channel blocker, when P2XR-mediated currents are under study. Inhibition of the hP2X3R or hP2X2/3R by diclofenac could be overcome by prolonged ATP-application or increasing concentrations of the agonist alphabeta-meATP, respectively, indicating competition of diclofenac and the agonists. Molecular dynamics simulation showed that diclofenac largely overlaps with ATP bound to the open state of the hP2X3R. Our results strongly support a competitive antagonism through which diclofenac, by interacting with residues of the ATP-binding site, left flipper, and dorsal fin domains inhibits gating of P2X3R by conformational fixation of the left flipper and dorsal fin domains. In summary, we demonstrate the inhibition of the human P2X3 receptor by various NSAIDs. Diclofenac proved to be the most effective antagonist with a strong inhibition of hP2X3R and hP2X2/3R and a weaker inhibition of hP2X1R, hP2X4R and hP2X7R. Considering their involvement in nociception, inhibition of hP2X3R and hP2X2/3R by micromolar concentrations of diclofenac may contribute to the analgesic effect as well as the side effect of taste disturbances of diclofenac and represent an additional mode of action besides the well-known high potency COX inhibition.

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“…P2X受体是一类响应细胞外ATP信号的配体门控离子通道，当细胞外的ATP作用于细胞膜上的P2X受体时，离子通道开放，允许钠离子、钾离子、钙离子等阳离子跨膜运输［ 29 ］。迄今，在哺乳动物体内发现了七种不同的P2X亚型（P2X1~7），其以同源或异源的方式组装在一起，形成三聚体离子通道结构。P2X受体单个亚基的形状似海豚，根据各结构域在亚基上所处的位置，P2X受体各组成部分分别命名为头部、左鳍、右鳍、背鳍、身体和尾部，其中头部、左鳍、右鳍、背鳍和身体区域构成胞外区域，尾部的两个α螺旋构成跨膜区［ 30 ］（图2 A）。Hattori等［ 31 ］报道了斑马鱼P2X4受体开放态结构，同时也揭示了ATP结合位点，并提出了P2X受体的激活机制。P2X受体的激动剂结合于每个亚基与相邻亚基交界处的空隙中，结合位点由背鳍、左鳍和相邻亚基的头部构成，虽然配体结合口袋主要位于胞外区域，但其与P2X受体结合的过程会带动受体整体构象产生变化来协调配合，最终实现离子通道开放。ATP的结合会导致头部向下摆动而背鳍上移向头部靠近，左鳍向下移动，整个ATP结合口袋呈现出一种“收紧”的运动趋势，背鳍和左鳍则分别带动与其相连的β折叠运动，导致身体下部外扩，这一系列的变化会引起跨膜区结构重排，使跨膜区构成的中央孔道扩大，从而使闸门位置打开，离子进入细胞内［ 32 - 34 ］。…”

Section: 嘌呤能配体门控离子通道受体unclassified

Recent progress in understanding the intracellular domain's gating and functional roles in trimeric ligand-gated ion channels

LU,

LIN,

WANG

2024

J Zhejiang Univ (Med Sci)

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配体门控离子通道是一大类重要的膜蛋白。嘌呤能配体门控离子通道（P2X）受体和酸敏感离子通道（ASIC）是三聚体配体门控离子通道的代表成员。P2X受体胞内区域的结构差异可影响脱敏过程，胞内区域的侧窗可作为离子渗透到细胞内的潜在路径并对离子选择性有决定作用，胞内区域众多氨基酸残基的磷酸化参与调节离子通道的活性。此外，胞内区域与 N -甲基- D -天冬氨酸受体、γ-氨基丁酸受体、5-羟色胺受体和N型乙酰胆碱受体等其他配体门控离子通道存在相互作用并介导突触可塑性等病理生理过程。ASIC胞内区域的构象变化会暴露胞内信号分子的结合位点并促进代谢信号转导，胞内区域的氨基酸Val16、Ser17、Ile18、Gln19和Ala20可以调节通道上膜表达并参与门控过程，胞内区域的PDZ结构域可与多种细胞内蛋白质如骨架蛋白CIPP和p11相互作用从而参与对受体的调控，胞内区域羧基端和氨基端的众多磷酸化位点参与了对受体的调控。此外，胞内区域参与了疼痛、缺血性脑卒中、精神疾病、神经退行性疾病等多种病理生理过程。本文综述了P2X受体和ASIC胞内区域的结构以及在调节离子通道的门控特性和病理生理功能中的作用，以期为三聚体配体门控离子通道的药物研发提供新思路。

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How Structural Biology Has Directly Impacted Our Understanding of P2X Receptor Function and Gating

Cited by 13 publications

References 81 publications

Diclofenac and other non-steroidal anti-inflammatory drugs (NSAIDs) are competitive antagonists of the human P2X3 receptor

Diclofenac and other non-steroidal anti-inflammatory drugs (NSAIDs) are competitive antagonists of the human P2X3 receptor

Diclofenac and other Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are Competitive Antagonists of the human P2X3 Receptor

Recent progress in understanding the intracellular domain's gating and functional roles in trimeric ligand-gated ion channels

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