6-Furopyridine Hexamethylene Amiloride Is a Non-Selective P2X7 Receptor Antagonist
Peter Cuthbertson1,2, Amal Elhage1,2, Dena Al-Rifai1,2
1Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia.
Abstract:
P2X7 is an extracellular adenosine 5'-triphopshate (ATP)-gated cation channel present on leukocytes, where its activation induces pro-inflammatory cytokine release and ectodomain shedding of cell surface molecules. Human P2X7 can be partially inhibited by amiloride and its derivatives at micromolar concentrations. This study aimed to screen a library of compounds derived from amiloride or its derivative 5-(N,N-hexamethylene) amiloride (HMA) to identify a potential P2X7 antagonist. 6-Furopyridine HMA (6-FPHMA) was identified as a novel P2X7 antagonist and was characterized further. 6-FPHMA impaired ATP-induced dye uptake into human RPMI8226 multiple myeloma cells and human P2X7-HEK293 cells, in a concentration-dependent, non-competitive manner. Likewise, 6-FPHMA blocked ATP-induced Ca2+ fluxes in human P2X7-HEK293 cells in a concentration-dependent, non-competitive manner. 6-FPHMA inhibited ATP-induced dye uptake into human T cells, and interleukin-1β release within human blood and CD23 shedding from RPMI8226 cells. 6-FPHMA also impaired ATP-induced dye uptake into murine P2X7- and canine P2X7-HEK293 cells. However, 6-FPHMA impaired ATP-induced Ca2+ fluxes in human P2X4-HEK293 cells and non-transfected HEK293 cells, which express native P2Y1, P2Y2 and P2Y4. In conclusion, 6-FPHMA inhibits P2X7 from multiple species. Its poor selectivity excludes its use as a specific P2X7 antagonist, but further study of amiloride derivatives as P2 receptor antagonists is warranted.
Insights
A novel compound, 6-Furopyridine HMA (6-FPHMA), was identified as a P2X7 antagonist. While effective against P2X7 from multiple species, its lack of selectivity limits its therapeutic potential.
Area of Science:
- Pharmacology
- Immunology
- Molecular Biology
Background:
- The P2X7 receptor (P2X7) is a critical mediator of inflammation, involved in cytokine release and cell surface molecule shedding.
- Amiloride and its derivatives show partial inhibition of human P2X7, suggesting potential for developing specific antagonists.
- Identifying selective P2X7 antagonists is crucial for modulating inflammatory responses.
Purpose of the Study:
- To screen amiloride-derived compounds for novel P2X7 antagonists.
- To characterize the inhibitory effects of a newly identified compound, 6-Furopyridine HMA (6-FPHMA), on P2X7.
- To assess the species selectivity and potential therapeutic applications of 6-FPHMA.
Main Methods:
- Screening of an amiloride derivative library to identify P2X7 antagonists.
- Characterization of 6-FPHMA using ATP-induced dye uptake and Ca2+ flux assays in various cell lines (HEK293, RPMI8226, T cells).
- Evaluation of 6-FPHMA's effects on cytokine release (interleukin-1β) and ectodomain shedding (CD23).
Main Results:
- 6-Furopyridine HMA (6-FPHMA) was identified as a novel P2X7 antagonist.
- 6-FPHMA non-competitively inhibited ATP-induced dye uptake and Ca2+ fluxes in human, murine, and canine P2X7 expressing cells.
- 6-FPHMA demonstrated cross-reactivity with P2X4 and other P2 receptors, indicating poor selectivity.
Conclusions:
- 6-FPHMA acts as a potent inhibitor of P2X7 across multiple species.
- The lack of selectivity of 6-FPHMA precludes its use as a specific P2X7 antagonist.
- Further investigation into amiloride derivatives for developing selective P2 receptor antagonists is warranted.
More Related Videos
10:29Multi-photon Intracellular Sodium Imaging Combined with UV-mediated Focal Uncaging of Glutamate in CA1 Pyramidal Neurons
Published on: October 8, 2014
07:16Methods for the Discovery of Novel Compounds Modulating a Gamma-Aminobutyric Acid Receptor Type A Neurotransmission
Published on: August 16, 2018
Related Concept Videos
01:12Antiarrhythmic Drugs: Class III Agents as Potassium Channel Blockers
01:17Drugs for Treatment of Diarrhea-Predominant IBS
Two specific drugs used in the treatment are alosetron (Lotronex) and eluxadoline (Viberzi). Alosetron, a 5-HT3 antagonist, works by slowing the movement of stools in the gut, reducing bowel...
01:17Pore Transport and Ion-Pair Transport
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct...
01:28Antihypertensive Drugs: Potassium-Sparing Diuretics
01:20Antiplatelet Drugs: Prostaglandin Synthesis, P2Y12 and Glycoprotein IIb/IIIa Inhibitors
Prostaglandin synthesis inhibitors, exemplified by the widely known aspirin, wield their power by irreversibly acetylating...
01:10Drugs that Destabilize Microtubules