Biostable aptamers with antagonistic properties to the neuropeptide nociceptin/orphanin FQ

The neuropeptide nociceptin/orphanin FQ (N/OFQ), the endogenous ligand of the opioid receptor-like 1 (ORL1) receptor, has been shown to play a prominent role in the regulation of several biological functions such as pain and stress. Here we describe the isolation and characterization of N/OFQ binding biostable RNA aptamers (Spiegelmers) using a mirror-image in vitro selection approach. Spiegelmers are l-enantiomeric oligonucleotide ligands that display high affinity and specificity to their targets and high resistance to enzymatic degradation compared to d-oligonucleotides. A representative Spiegelmer from the selections performed was size-minimized to two distinct sequences capable of high affinity binding to N/OFQ. The Spiegelmers were shown to antagonize binding of N/OFQ to the ORL1 receptor in a binding-competition assay. The calculated IC(50) values for the Spiegelmers NOX 2149 and NOX 2137a/b were 110 nM and 330 nM, respectively. The competitive antagonistic properties of these Spiegelmers were further demonstrated by their effective and specific inhibition of G-protein activation in two additional models. The Spiegelmers antagonized the N/OFQ-induced GTPγS incorporation into cell membranes of a CHO-K1 cell line expressing the human ORL1 receptor. In oocytes from Xenopus laevis, NOX 2149 showed an antagonistic effect to the N/OFQ-ORL 1 receptor system that was functionally coupled with G-protein-regulated inwardly rectifying K(+) channels

Qualifikationsrahmen Wirtschaftsingenieurwesen

Qualifikationsrahmen, Wirtschaftsingenieurwese

Synthesis and Pharmacological Evaluation of 5‑Pyrrolidinylquinoxalines as a Novel Class of Peripherally Restricted κ‑Opioid Receptor Agonists

5-Pyrrolidinyl substituted perhydroquinoxalines were designed as conformationally restricted κ-opioid receptor agonists restricted to the periphery. The additional N atom of the quinoxaline system located outside the ethylenediamine κ pharmacophore allows the fine-tuning of the pharmacodynamic and pharmacokinetic properties. The perhydroquinoxalines were synthesized stereoselectively using the concept of late stage diversification of the central building blocks <b>14</b>. In addition to high κ-opioid receptor affinity they demonstrate high selectivity over μ, δ, σ₁, σ₂, and NMDA receptors. In the [³⁵S]­GTPγS assay full agonism was observed. Because of their high polarity, the secondary amines <b>14a</b> (log <i>D</i>_7.4 = 0.26) and <b>14b</b> (log <i>D</i>_7.4 = 0.21) did not penetrate an artificial blood–brain barrier. <b>14b</b> was able to inhibit the spontaneous pain reaction after rectal mustard oil application to mice (ED₅₀ = 2.35 mg/kg). This analgesic effect is attributed to activation of peripherally located κ receptors, since <b>14b</b> did not affect centrally mediated referred allodynia and hyperalgesia

Discovery of Spiro[cyclohexane-dihydropyrano[3,4‑<i>b</i>]indole]-amines as Potent NOP and Opioid Receptor Agonists

We report the discovery of spiro­[cyclohexane-pyrano­[3,4-<i>b</i>]­indole]-amines, as functional nociceptin/orphanin FQ peptide (NOP) and opioid receptor agonists with strong efficacy in preclinical models of acute and neuropathic pain. Utilizing 4-(dimethylamino)-4-phenylcyclo-hexanone <b>1</b> and tryptophol in an oxa-Pictet–Spengler reaction led to the formation of spiroether <b>2</b>, representing a novel NOP and opioid peptide receptor agonistic chemotype. This finding initially stems from the systematic derivatization of <b>1</b>, which resulted in alcohols <b>3</b>–<b>5</b>, ethers <b>6</b> and <b>7</b>, amines <b>8</b>–<b>10</b>, <b>22</b>–<b>24</b>, and <b>26</b>–<b>28</b>, amides <b>11</b> and <b>25</b>, and urea <b>12</b>, many with low nanomolar binding affinities at the NOP and mu opioid peptide (MOP) receptors

Discovery of a Potent Analgesic NOP and Opioid Receptor Agonist: Cebranopadol

In a previous communication, our efforts leading from <b>1</b> to the identification of spiro­[cyclohexane-dihydropyrano­[3,4-<i>b</i>]­indole]-amine <b>2a</b> as analgesic NOP and opioid receptor agonist were disclosed and their favorable in vitro and in vivo pharmacological properties revealed. We herein report our efforts to further optimize lead <b>2a</b>, toward <i>trans</i>-6′-fluoro-4′,9′-dihydro-<i>N</i>,<i>N</i>-dimethyl-4-phenyl-spiro­[cyclohexane-1,1′(3′<i>H</i>)-pyrano­[3,4-<i>b</i>]­indol]-4-amine (cebranopadol, <b>3a</b>), which is currently in clinical development for the treatment of severe chronic nociceptive and neuropathic pain