The Suramin Analog 4,4′,4″,4″′-(Carbonylbis(imino-5,1,3-benzenetriylbis (carbonylimino)))tetra-kis-benzenesulfonic Acid (NF110) Potently Blocks P2X₃ Receptors: Subtype Selectivity Is Determined by Location of Sulfonic Acid Groups

Abstract

We have previously identified the suramin analog 4,4Ј,4Љ,4ٞ-(carbonylbis(imino-5,1,3-benzenetriylbis(carbonylimino)))tetrakis-benzene-1,3-disulfonic acid (NF449) as a low nanomolar potency antagonist of recombinant P2X 1 receptors. Here, we characterize, by two-electrode voltage-clamp electrophysiology, three isomeric suramin analogs designated para-4,4Ј,4Љ,4ٞ-(carbonylbis(imino-5,1,3-benzenetriylbis (carbonylimino)))tetrakis-benzenesulfonic acid (NF110), meta- (3,3Ј,3Љ,3ٞ-(carbonylbis(imino-5,1,3-benzenetriylbis (carbonylimino)))tetra-kis-benzenesulfonic acid (NF448), and ortho- (2,2Ј,2Љ,2ٞ-(carbonylbis(imino-5,1,3-benzenetriylbis (carbonylimino)))tetra-kis-benzenesulfonic acid (MK3) with respect to their potency in antagonizing rat P2X receptor-mediated inward currents in Xenopus laevis oocytes. Meta, para, and ortho refer to the position of the single sulfonic acid group relative to the amide bond linking the four symmetrically oriented benzenesulfonic acid moieties to the central, invariant suramin core. NF448, NF110, and MK3 were Ͼ200-fold less potent in blocking P2X 1 receptors than NF449, from which they differ structurally only by having one instead of two sulfonic acid residues per benzene ring. Although the meta-and ortho-isomers retained P2X 1 receptor selectivity, the para-isomer NF110 exhibited a significantly increased activity at P2X 3 receptors (K i ϳ 36 nM) and displayed the following unique selectivity profile among suramin derivatives: P2X 2ϩ3 ϭ P2X 3 Ͼ P2X 1 Ͼ P2X 2 Ͼ Ͼ P2X 4 Ͼ P2X 7 . The usefulness of NF110 as a P2X 3 receptor antagonist in native tissues could be demonstrated by showing that NF110 blocks ␣␤-methylene-ATP-induced currents in rat dorsal root ganglia neurons with similar potency as recombinant rat P2X 3 receptors. Together, these data highlight the importance of both the number and exact location of negatively charged groups for P2X subtype potency and selectivity.P2X receptors constitute an abundant class of cell surface receptors that open an intrinsic pore that becomes permeable to small cations when exposed to extracellular ATP and related nucleotides (North, 2002). The seven known subunit isoforms, designated P2X 1 -P2X 7 , assemble into homotrimeric and heterotrimeric receptor channels (Nicke et al., 1998;Aschrafi et al., 2004;Mio et al., 2005), resulting in large receptor subtype diversity.Among the numerous sensory processes in which P2X receptors have been implicated, their involvement in nocicepThis research project is supported by the START-Program of the Faculty of Medicine, RWTH Aachen University (to R.H.); by a grant of the "Fonds der Chemischen Industrie" (to G.L.); and by the Deutsche Forschungsgemeinschaft grants GRK 677/1&2 (to M.U.K.), La 350/7-3 and GRK 137/3 (to G.L.), and Schm 536/6-1; FOR450, TP11 (to G.S.). Preliminary results of this work were presented as a meeting abstract: Hausmann R, Rettinger J, Kassack M, Lambrecht G, and Schmalzing G (2004) Characterization of the novel suramin analog NF110 as a potent P2X 3 receptor-selective antagon...

NF546 [4,4′-(Carbonylbis(imino-3,1-phenylene-carbonylimino-3,1-(4-methyl-phenylene)-carbonylimino))-bis(1,3-xylene-α,α′-diphosphonic Acid) Tetrasodium Salt] Is a Non-Nucleotide P2Y11 Agonist and Stimulates Release of Interleukin-8 from Human Monocyte-Derived Dendritic Cells

“…The iantherans are of limited availability because of their marine sponge origin. Naphthalene sulfonic acid urea derivatives have been an excellent source of selective and potent P2 receptor ligands (Damer et al, 1998;Braun et al, 2001;Kassack et al, 2004;Ullmann et al, 2005;Hausmann et al, 2006). We have thus performed a systematic screening of a compound library of naphthalene sulfonic and phosphonic acid urea derivatives for P2Y 11 receptor activation or inhibition by use of a fluorescence-based calcium assay .…”

NF449 Is a Novel Inhibitor of Fibroblast Growth Factor Receptor 3 (FGFR3) Signaling Active in Chondrocytes and Multiple Myeloma Cells

“…8). As demonstrated by Hausmann et al (43), selectivity of suramin analogs to P2X receptors is primarily determined by the location of sulfonic acid groups. Three-dimensional structural modeling suggests that the location of sulfonic acid groups is also responsible for the different activities toward FGFR3.…”

Aminoglycoside block of P2X2 receptors heterologously expressed in Xenopus laevis oocytes

“…Moreover, the P2X2-X1 chimera can serve as a model of the P2X1 receptor in terms of binding/ gating and pore properties without the bias of fast desensitization [34,43] because the pore region, the channel gate and the ATP binding site do not include residues of the N-terminal tail or the transmembrane domain I [4,[6][7][8][9].…”