Dataset Information

Identification and in vitro pharmacological characterization of a novel and selective α7 nicotinic acetylcholine receptor agonist, Br-IQ17B.

ABSTRACT: Alpha7-nicotinic acetylcholine receptor (α7 nAChR) is a ligand-gated Ca(2+)-permeable ion channel implicated in cognition and neuropsychiatric disorders. Activation of α7 nAChR improves learning, memory, and sensory gating in animal models. To identify novel α7 nAChR agonists, we synthesized a series of small molecules and characterized a representative compound, Br-IQ17B, N-[(3R)-1-azabicyclo[2,2,2]oct-3-yl]-5-bromoindolizine-2-carboxamide, which specifically activates α7 nAChR.Two-electrode voltage clamp (TEVC) recordings were primarily used for screening in Xenopus oocytes expressing human α7 nAChR. Assays, including radioisotope ligand binding, Western blots, whole-cell recordings of hippocampal culture neurons, and spontaneous IPSC recordings of brain slices, were also utilized to evaluate and confirm the specific activation of α7 nAChR by Br-IQ17B.Br-IQ17B potently activates α7 nAChR with an EC50 of 1.8±0.2 μmol/L. Br-IQ17B is selective over other subtypes such as α4β2 and α3β4, but it blocks 5-HT3A receptors. Br-IQ17B displaced binding of the α7 blocker [(3)H]-MLA to hippocampal crude membranes with a Ki of 14.9±3.2 nmol/L. In hippocampal neurons, Br-IQ17B evoked α7-like currents that were inhibited by MLA and enhanced in the presence of the α7 PAM PNU-120596. In brain slice recordings, Br-IQ17B enhanced GABAergic synaptic transmission in CA1 neurons. Mechanistically, Br-IQ17B increased ERK1/2 phosphorylation that was MLA-sensitive.We identified the novel, potent, and selective α7 agonist Br-IQ17B, which enhances synaptic transmission. Br-IQ17B may be a helpful tool to understand new aspects of α7 nAChR function, and it also has potential for being developed as therapy for schizophrenia and cognitive deficits.

SUBMITTER: Tang JS

PROVIDER: S-EPMC4648113 | biostudies-other | 2015 Jul

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:Purpose: Eye drop application of PNU-282987, an α7 nAChR agonist, causes regeneration through development of Müller derived progeintor cells (MDPCs) that are generated as a result of signaling from activated retinal pigment epitheilal (RPE) cells . The goals of this study are to examine the transcrptional changes through RNA-seq after treatment with PNU-282987 in mammalian RPE cell culture that lead to the dedifferentation and generation of MDPCs in the adult mammalian retina. To validate the RNAseq findings, RT-qPCR was used. Finally, several genes that were identified were knocked out in RPE culture through a novel CRISPR/Cas12 system and the resulting activated supernatant was assayed for it's ability to cause neurogensis in the adult rodent retina. Methods: Retinal pigment epithelium (RPE-J) cells were treated with DMSO (vehicle control), nicotine (an α7 nAChR agonist that does not cause regeneration as a control), or PNU-282987, or MLA (an α7 nAChR antagonist as a control). The cells were treated for either 30 minutes, 1 hour, 3 hours, 8 hours, or 12 hours. RNA was extracted from RPE-J cells using Zymo Direct-zol RNA miniprep kit and mRNA proflies were generated by GeneWiz with the Illumina NextSeq 550 high-output platform. Results: Using an optimized data analysis workflow, GeneWiz mapped about 30 million sequence reads per sample to the rat genome (Rnor6.0) and identified over 15,000 transcripts. Deseq2 analysis was performed to determine log 2 fold changes in gene expression compared to DMSO control, nicotine control, and MLA control, and found over 450 significantly differentially expressed genes. Twelve genes were validated with qRT–PCR to compare trends and were found to be consistent. Eight genes identified through RNA-seq involved in inflammation response, receptor signaling, WNT signaling and early retinal development were knocked out using CRISPR/Cas12 in RPE-J culture. Intravitreal injections of KO lines supernatant after treatment with PNU-282987 was assayed for invovlment of these genes in the adult neuroregeneration response. Conclusions: PNU-282987 activation of RPE causes signficant transcript profile changes in RPE-J cell culture that leads to significant differentially expressed genes as seen in RNA-seq profiles and validated with qRT-PCR. Further, several genes identified in the RNA-seq were found to be necessary for the neurogenic response as seen with generation of KO lines of RPE. Our study is the first to show that activaiton of the α7 nAChR on RPE leads to genetic changes sufficient to induce adult mammalian neurogenesis in the rodent retina and that several novel genes are invovled in this pathway in mammals as compared to other vertebrate models of retinal regeneration.

Dataset Information

Identification and in vitro pharmacological characterization of a novel and selective α7 nicotinic acetylcholine receptor agonist, Br-IQ17B.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure