ORCID Profile
0000-0003-2514-9189
Current Organisations
National Institutes of Health
,
Macquarie University
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Publisher: Cold Spring Harbor Laboratory
Date: 27-03-2019
DOI: 10.1101/589341
Abstract: Synthetic cannabinoids are a commonly used class of recreational drugs that can have significant adverse effects. There have been sporadic reports of co-consumption of illicit drugs with rodenticides such as warfarin and brodifacoum (BFC) over the past 20 years but recently, hundreds of people have been reported to have been poisoned with a mixture of synthetic cannabinoids and BFC. We have sought to establish whether BFC directly affects cannabinoid receptors, or their activation by the synthetic cannabinoid CP55940 or the phytocannabinoid Δ 9 -tetrahydrocannabinol (Δ 9 -THC). The effects of BFC on the hyperpolarization of wild type AtT20 cells, or AtT20 cells stably expressing human CB 1 - and CB 2 -mediated receptors, were studied using a fluorescent assay of membrane potential. The effects of BFC on CB 1 and CB 2 mediated inhibition of forskolin-stimulated adenylyl cyclase (AC) activation was measured using a BRET assay of cAMP levels in HEK 293 cells stably expressing human CB 1 and CB 2 . BFC did not activate CB 1 or CB 2 receptors, or affect the hyperpolarization of wild type AtT20 cells produced by somatostatin. BFC (10 µ M) did not affect the hyperpolarization of AtT20-CB 1 or AtT20-CB 2 cells produced by CP55940 or Δ 9 -THC. BFC (1 µ M) did not affect the inhibition of forskolin-stimulated AC activity by CP55940 in HEK 293 cells expressing CB 1 or CB 2 . BFC (1 µ M) also failed to affect the desensitization of CB 1 and CB 2 signalling produced by prolonged (30 min) application of CP55940 or Δ 9 -THC to AtT20 cells. BFC is not a cannabinoid receptor agonist, and appeared not to affect cannabinoid receptor activation. Our data suggests there is no pharmacodynamic rationale for mixing BFC with synthetic cannabinoids, however, it does not speak to whether BFC may affect synthetic cannabinoid metabolism or biodistribution. The reasons underlying the mixing of BFC with synthetic cannabinoids are unknown, and it remains to be established whether the “contamination” was deliberate or accidental. However, the consequences for people who ingested the mixture were often serious, and sometimes fatal, but this seems unlikely to be due to BFC action at cannabinoid receptors.
Publisher: Mary Ann Liebert Inc
Date: 09-2019
Publisher: SPIE
Date: 04-03-2019
DOI: 10.1117/12.2509582
Publisher: American Chemical Society (ACS)
Date: 27-07-2016
DOI: 10.1021/ACSCHEMNEURO.6B00137
Abstract: Indole and indazole synthetic cannabinoids (SCs) featuring l-valinate or l-tert-leucinate pendant group have recently emerged as prevalent recreational drugs, and their use has been associated with serious adverse health effects. Due to the limited pharmacological data available for these compounds, 5F-AMBICA, 5F-AMB, 5F-ADB, AMB-FUBINACA, MDMB-FUBINACA, MDMB-CHMICA, and their analogues were synthesized and assessed for cannabimimetic activity in vitro and in vivo. All SCs acted as potent, highly efficacious agonists at CB1 (EC50 = 0.45-36 nM) and CB2 (EC50 = 4.6-128 nM) receptors in a fluorometric assay of membrane potential, with a general preference for CB1 activation. The cannabimimetic properties of two prevalent compounds with confirmed toxicity in humans, 5F-AMB and MDMB-FUBINACA, were demonstrated in vivo using biotelemetry in rats. Bradycardia and hypothermia were induced by 5F-AMB and MDMB-FUBINACA doses of 0.1-1 mg/kg (and 3 mg/kg for 5F-AMB), with MDMB-FUBINACA showing the most dramatic hypothermic response recorded in our laboratory for any SC (>3 °C at 0.3 mg/kg). Reversal of hypothermia by pretreatment with a CB1, but not CB2, antagonist was demonstrated for 5F-AMB and MDMB-FUBINACA, consistent with CB1-mediated effects in vivo. The in vitro and in vivo data indicate that these SCs act as highly efficacious CB receptor agonists with greater potency than Δ(9)-THC and earlier generations of SCs.
Publisher: Cold Spring Harbor Laboratory
Date: 13-10-2023
Publisher: American Chemical Society (ACS)
Date: 15-09-2022
DOI: 10.1021/ACS.BIOCONJCHEM.2C00334
Abstract: Synthetic molecules that form a covalent bond upon binding to a targeted biomolecule (proximity-induced reactivity) are the subject of intense biomedical interest for the unique pharmacological properties imparted by irreversible binding. However, off-target covalent labeling and the lack of molecules with sufficient specificity limit more widespread applications. We describe the first ex le of a cross-linking platform that uses a synthetic peptide epitope and a single domain antibody (or nanobody) pair to form a covalent linkage rapidly and specifically. The rate of the cross-linking reaction between peptide and nanobody is faster than most other biocompatible cross-linking reactions, and it can be used to label live cells expressing receptor-nanobody fusions. The rapid kinetics of this system allowed us to probe the consequences on signaling for ligand cross-linking to the A2A-adenosine receptor. Our method may be generally useful to site-specifically link synthetic molecules to receptors on mammalian cell surfaces.
Publisher: Wiley
Date: 26-02-2020
DOI: 10.1002/PRP2.566
Publisher: Wiley
Date: 12-2019
DOI: 10.1111/BPH.14829
Publisher: Elsevier
Date: 2021
Publisher: Springer US
Date: 26-09-2020
Publisher: American Chemical Society (ACS)
Date: 05-08-2022
DOI: 10.1021/ACSCHEMBIO.2C00407
Abstract: Peptide epitope tags offer a valuable means for detection and manipulation of protein targets for which high quality detection reagents are not available. Most commonly used epitope tags are bound by conventional, full-size antibodies (Abs). The complex architecture of Abs complicates their application in protein engineering and intracellular applications. To address these shortcomings, single domain antibodies (nanobodies, Nbs) that recognize short peptide epitopes have become increasingly prized. Here, we characterize the interaction between a Nb (Nb
Publisher: Elsevier
Date: 2023
Publisher: Frontiers Media SA
Date: 17-01-2022
DOI: 10.3389/FNCEL.2021.814547
Abstract: Neurons integrate inputs over different time and space scales. Fast excitatory synapses at boutons (ms and μm), and slow modulation over entire dendritic arbors (seconds and mm) are all ultimately combined to produce behavior. Understanding the timing of signaling events mediated by G-protein-coupled receptors is necessary to elucidate the mechanism of action of therapeutics targeting the nervous system. Measuring signaling kinetics in live cells has been transformed by the adoption of fluorescent biosensors and dyes that convert biological signals into optical signals that are conveniently recorded by microscopic imaging or by fluorescence plate readers. Quantifying the timing of signaling has now become routine with the application of equations in familiar curve fitting software to estimate the rates of signaling from the waveform. Here we describe ex les of the application of these methods, including (1) Kinetic analysis of opioid signaling dynamics and partial agonism measured using cAMP and arrestin biosensors (2) Quantifying the signaling activity of illicit synthetic cannabinoid receptor agonists measured using a fluorescent membrane potential dye (3) Demonstration of multiplicity of arrestin functions from analysis of biosensor waveforms and quantification of the rates of these processes. These ex les show how temporal analysis provides additional dimensions to enhance the understanding of GPCR signaling and therapeutic mechanisms in the nervous system.
Publisher: Informa UK Limited
Date: 15-11-2021
Publisher: Wiley
Date: 09-01-2018
DOI: 10.1002/HRM.21891
Abstract: Using a s le composed of 701 food and beverage managers nested in 120 units and 40 Asian hotel properties, in the current study we investigated the effects of unit high‐performance work system (HPWS) use and unit support climate on in idual unit members' human resource outcomes (job performance behaviors: in‐role and organizational citizenship behaviors). The results support the hypothesized relationships among unit HPWS use, unit support climate, in idual affective commitment, and in idual job performance behaviors. The current study's findings illuminate the ways (e.g., mediation and moderation) in which the unit support climate advances positive organizationally relevant in idual‐level human resource outcomes. Findings, implications, and limitations as well as avenues for future research are discussed.
Location: Australia
No related grants have been discovered for Shivani Sachdev.