Biology subjects

Cantwell, L.

Publications and source records attributed to Cantwell, L..

5 recordsLinked to original sources

bioRxiv2026

GAT1508, a selective neuronal GIRK1/2 activator, exhibits superior antiepileptic efficacy and synergizes with cannabidiol

G protein-gated inwardly rectifying potassium (GIRK; Kir3) channels are key regulators of neuronal excitability and represent promising therapeutic targets for epilepsy. Here, we characterize GAT1508, a urea-based small-molecule activator selectively targeting neuronal GIRK1/2 heterotetramers, and compare its efficacy with previously described urea compounds ML297 and GiGA1. In a pentylenetetrazole (PTZ)-induced seizure model, GAT1508 demonstrated robust antiseizure activity, outperforming both ML297 and GiGA1 and achieving efficacy comparable to valproic acid. Electrophysiological studies using two-electrode voltage clamp in Xenopus oocytes revealed that GAT1508, unlike ML297 and GiGA1, selectively activates GIRK1/2 channels without significant activation of cardiac GIRK1/4 channels, suggesting reduced risk of cardiovascular side effects. Structural and computational analyses indicate that enhanced stabilization of GAT1508 compared to ML297 within the GIRK1/2 binding pocket promotes both ion permeation and channel gating through coordinated interactions with key residues. Furthermore, GAT1508, like the two other urea drugs, exhibited synergistic activation of GIRK channels when combined with G{beta}{gamma}-mediated pathways and significantly potentiated the antiseizure effects of cannabidiol (CBD) in both hippocampal slice recordings and in vivo seizure models. These findings establish GAT1508 as a potent and selective GIRK1/2 activator and support a novel combination therapeutic strategy for epilepsy based on convergent GIRK channel modulation.

pharmacology and toxicology↗

bioRxiv2024

Negative allosteric modulation of cannabinoid CB1 receptor signaling suppresses opioid-mediated tolerance and withdrawal without blocking opioid antinociception

The direct blockade of CB1 cannabinoid receptors produces therapeutic effects as well as adverse side-effects that limit their clinical potential. CB1 negative allosteric modulators (NAMs) represent an indirect approach to decrease the affinity and/or efficacy of orthosteric cannabinoid ligands or endocannabinoids at CB1. We recently reported that GAT358, a CB1-NAM, blocked opioid-induced mesocorticolimbic dopamine release and reward via a CB1-allosteric mechanism of action. Whether a CB1-NAM dampens opioid-mediated therapeutic effects such as analgesia or alters other unwanted side-effects of opioids remain unknown. Here, we characterized the effects of GAT358 on nociceptive behaviors in the presence and absence of morphine. We examined the impact of GAT358 on formalin-evoked pain behavior and Fos protein expression, a marker of neuronal activation, in the lumbar dorsal horn. We also assessed the impact of GAT358 on morphine-induced slowing of colonic transit, tolerance, and withdrawal behaviors. GAT358 attenuated morphine antinociceptive tolerance without blocking acute antinociception. GAT358 also reduced morphine-induced slowing of colonic motility without impacting fecal boli production. GAT358 produced antinociception in the presence and absence of morphine in the formalin model of inflammatory nociception and reduced the number of formalin-evoked Fos protein-like immunoreactive cells in the lumbar spinal dorsal horn. Finally, GAT358 mitigated the somatic signs of naloxone-precipitated, but not spontaneous, opioid withdrawal following chronic morphine dosing in mice. Our results support the therapeutic potential of CB1-NAMs as novel drug candidates aimed at preserving opioid-mediated analgesia while preventing their unwanted side-effects. Our studies also uncover previously unrecognized antinociceptive properties associated with an arrestin-biased CB1-NAMs. HighlightsO_LICB1 negative allosteric modulator (NAM) GAT358 attenuated morphine tolerance C_LIO_LIGAT358 reduced morphine-induced slowing of colonic motility but not fecal production C_LIO_LIGAT358 was antinociceptive for formalin pain alone and when combined with morphine C_LIO_LIGAT358 reduced formalin-evoked Fos protein expression in the lumbar spinal cord C_LIO_LIGAT358 mitigated naloxone precipitated withdrawal after chronic morphine dosing C_LI

neuroscience↗

bioRxiv2022

TRAP1 S-nitrosylation as a model of population-shift mechanism to study the effects of nitric oxide on redox-sensitive oncoproteins.

S-nitrosylation is a post-translational modification in which nitric oxide (NO) binds to the thiol group of cysteine, generating an S-nitrosothiol (SNO) adduct. S-nitrosylation has different physiological roles, and its alteration has also been linked to a growing list of pathologies, including cancer. SNO can affect the function and stability of different proteins, such as the mitochondrial chaperone TRAP1. Interestingly, the SNO site (C501) of TRAP1 is in the proximity of another cysteine (C527). This feature suggests that the S-nitrosylated C501 could engage in a disulfide bridge with C527 in TRAP1, resembling the well-known ability of S-nitrosylated cysteines to resolve in disulfide bridge with vicinal cysteines. We used enhanced sampling simulations and in-vitro biochemical assays to address the structural mechanisms induced by TRAP1 S-nitrosylation. We showed that the SNO site induces conformational changes in the proximal cysteine and favors conformations suitable for disulfide-bridge formation. We explored 4172 known S-nitrosylated proteins using high-throughput structural analyses. Furthermore, we carried out coarse-grain simulations of 44 proteins to account for protein dynamics in the analyses. This resulted in the identification of up to 1248 examples of proximal cysteines which could sense the redox state of the SNO site, opening new perspectives on the biological effects of redox switches. In addition, we devised two bioinformatic workflows (https://github.com/ELELAB/SNO_investigation_pipelines) to identify proximal or vicinal cysteines for a SNO site with accompanying structural annotations. Finally, we analyzed mutations in tumor suppressor or oncogenes in connection with the conformational switch induced by S-nitrosylation. We classified the variants as neutral, stabilizing, or destabilizing with respect to the propensity to be S-nitrosylated and to undergo the population-shift mechanism. The methods applied here provide a comprehensive toolkit for future high-throughput studies of new protein candidates, variant classification, and a rich data source for the research community in the NO field.

biochemistry↗

bioRxiv2022

Data Descriptor: Human whole exome genotype data for Alzheimer's Disease

Bigger sample size can help to identify new genetic variants contributing to an increased risk of developing Alzheimers disease. However, the heterogeneity of the whole-exome sequencing (WES) data generation methods presents a challenge to a joint analysis. Here we present a bioinformatics strategy for joint calling 20,504 WES samples collected across nine studies and sequenced using ten different capture kits in fourteen sequencing centers in the Alzheimers Disease Sequencing Project. gVCFs of samples were joint-called by the Genome Center for Alzheimers Disease into a single VCF, containing only positions within the union of capture kits. The VCF was then processed using specific strategies to account for the batch effects arising from the use of different capture kits from different studies. We identified 8.2 million autosomal variants. 96.82% of the variants are high-quality, and are located in 28,579 Ensembl transcripts. 41% of the variants are intronic and 15% are missense variants. 1.8% of the variants are with CADD>30. Our new strategy for processing these diversely generated WES samples has shown to generate high-quality data. The improved ability to combine data sequenced in different batches benefits the whole genomics research community. The WES data are accessible to the scientific community via https://dss.niagads.org/.

genetics↗

bioRxiv2018

VCPA: genomic variant calling pipeline and data management tool for Alzheimer’s Disease Sequencing Project

Summary: We report VCPA, our SNP/Indel Variant Calling Pipeline and data management tool used for analysis of whole genome and exome sequencing (WGS/WES) for the Alzheimers Disease Sequencing Project. VCPA consists of two independent but linkable components: pipeline and tracking database. The pipeline is coded in Workflow Description Language and is fully optimized for the Amazon elastic compute cloud environment. This includes steps for processing raw sequence reads including read alignment, and all the way up to variant calling using GATK. The tracking database allows users to dynamically view the statuses of jobs running and the quality metrics reported by the pipeline. Users can thus monitor the production process and diagnose if any problem arises during the procedure. All quality metrics (>100 collected per processed genome) are stored in the database, thus facilitating users to compare, share and visualize the results. To summarize, VCPA is functional equivalent to the CCDG/TOPMed pipeline. Together with the dockerized database (also available as Amazon Machine Image), users can easily process any WGS/WES data on Amazon cloud with minimal installation.\n\nAvailability: VCPA is released under the MIT license and is available for academic and nonprofit use for free. The pipeline source code and step-by-step instructions are available from the National Institute on Aging Genetics of Alzheimers Disease Data Storage Site (http://www.niagads.org/VCPA).\n\nContact: yyee@pennmedicine.upenn.edu or lswang@pennmedicine.upenn.edu\n\nSupplementary information: Supplementary data are available at Bioinformatics online.

bioinformatics↗