Publications by authors named "Le-Sha Zhang"

5 Publications

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Alteration of twinfilin1 expression underlies opioid withdrawal-induced remodeling of actin cytoskeleton at synapses and formation of aversive memory.

Mol Psychiatry 2021 May 7. Epub 2021 May 7.

Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.

Exposure to drugs of abuse induces alterations of dendritic spine morphology and density that has been proposed to be a cellular basis of long-lasting addictive memory and heavily depend on remodeling of its underlying actin cytoskeleton by the actin cytoskeleton regulators. However, the actin cytoskeleton regulators involved and the specific mechanisms whereby drugs of abuse alter their expression or function are largely unknown. Twinfilin (Twf1) is a highly conserved actin-depolymerizing factor that regulates actin dynamics in organisms from yeast to mammals. Despite abundant expression of Twf1 in mammalian brain, little is known about its importance for brain functions such as experience-dependent synaptic and behavioral plasticity. Here we show that conditioned morphine withdrawal (CMW)-induced synaptic structure and behavior plasticity depends on downregulation of Twf1 in the amygdala of rats. Genetically manipulating Twf1 expression in the amygdala bidirectionally regulates CMW-induced changes in actin polymerization, spine density and behavior. We further demonstrate that downregulation of Twf1 is due to upregulation of miR101a expression via a previously unrecognized mechanism involving CMW-induced increases in miR101a nuclear processing via phosphorylation of MeCP at Ser421. Our findings establish the importance of Twf1 in regulating opioid-induced synaptic and behavioral plasticity and demonstrate its value as a potential therapeutic target for the treatment of opioid addiction.
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May 2021

Propofol decreases the excitability of cholinergic neurons in mouse basal forebrain via GABA receptors.

Acta Pharmacol Sin 2019 Jun 26;40(6):755-761. Epub 2018 Oct 26.

Department of Pharmacology and Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, China.

Propofol is an intravenous anesthetic that can active γ-aminobutyric acid A (GABA) receptors and generate sedative-hypnotic effects. Propofol has been widely applied clinically to achieve sedation comparable to sleep in humans. The basal forebrain (BF) is a brain region that plays an important role in sleep-wake regulation. Previous studies suggest that propofol affects the sleep-wake circuit via the BF; however, the mechanism remains elusive. In the current study we investigated the effects of propofol on the inherent properties of cholinergic neurons and their ability to convert excitatory inputs into spikes in mouse BF slices using whole-cell patch clamp recordings. Bath application of propofol (10 μM) significantly elevated the threshold potentials (Vts), decreased the number of spikes in response to a depolarizing current injection, and augmented the inter-spike intervals (ISIs), energy barrier (Vts-Vrs), and absolute refractory periods (ARPs). These effects were eliminated by co-application of a GABA receptor antagonist picrotoxin (50 μM). Altogether, our results reveal that propofol decreases the excitability of cholinergic neurons in mouse BF via GABA receptors.
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June 2019

Role for engagement of β-arrestin2 by the transactivated EGFR in agonist-specific regulation of δ receptor activation of ERK1/2.

Br J Pharmacol 2015 Oct 23;172(20):4847-63. Epub 2015 Sep 23.

Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica and Collaborative Innovation Center for Brain Science, Chinese Academy of Science, Shanghai, China.

Background And Purpose: β-Arrestins function as signal transducers linking GPCRs to ERK1/2 signalling either by scaffolding members of ERK1/2s cascades or by transactivating receptor tyrosine kinases through Src-mediated release of transactivating factor. Recruitment of β-arrestins to the activated GPCRs is required for ERK1/2 activation. Our previous studies showed that δ receptors activate ERK1/2 through a β-arrestin-dependent mechanism without inducing β-arrestin binding to the δ receptors. However, the precise mechanisms involved remain to be established.

Experimental Approach: ERK1/2 activation by δ receptor ligands was assessed using HEK293 cells in vitro and male Sprague Dawley rats in vivo. Immunoprecipitation, immunoblotting, siRNA transfection, intracerebroventricular injection and immunohistochemistry were used to elucidate the underlying mechanism.

Key Results: We identified a new signalling pathway in which recruitment of β-arrestin2 to the EGFR rather than δ receptor was required for its role in δ receptor-mediated ERK1/2 activation in response to H-Tyr-Tic-Phe-Phe-OH (TIPP) or morphine stimulation. Stimulation of the δ receptor with ligands leads to the phosphorylation of PKCδ, which acts upstream of EGFR transactivation and is needed for the release of the EGFR-activating factor, whereas β-arrestin2 was found to act downstream of the EGFR transactivation. Moreover, we demonstrated that coupling of the PKCδ/EGFR/β-arrestin2 transactivation pathway to δ receptor-mediated ERK1/2 activation was ligand-specific and the Ser(363) of δ receptors was crucial for ligand-specific implementation of this ERK1/2 activation pathway.

Conclusions And Implications: The δ receptor-mediated activation of ERK1/2 is via ligand-specific transactivation of EGFR. This study adds new insights into the mechanism by which δ receptors activate ERK1/2.
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October 2015

Novel κ-opioid receptor agonist MB-1C-OH produces potent analgesia with less depression and sedation.

Acta Pharmacol Sin 2015 May 30;36(5):565-71. Epub 2015 Mar 30.

State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica and Collaborative Innovation Center for Brain Science, Chinese Academy of Sciences, Shanghai 201203, China.

Aim: To characterize the pharmacological profiles of a novel κ-opioid receptor agonist MB-1C-OH.

Methods: [(3)H]diprenorphine binding and [(35)S]GTPγS binding assays were performed to determine the agonistic properties of MB-1C-OH. Hot plate, tail flick, acetic acid-induced writhing, and formalin tests were conducted in mice to evaluate the antinociceptive actions. Forced swimming and rotarod tests of mice were used to assess the sedation and depression actions.

Results: In [(3)H]diprenorphine binding assay, MB-1C-OH did not bind to μ- and δ-opioid receptors at the concentration of 100 μmol/L, but showed a high affinity for κ-opioid receptor (Ki=35 nmol/L). In [(35)S]GTPγS binding assay, the compound had an Emax of 98% and an EC50 of 16.7 nmol/L for κ-opioid receptor. Subcutaneous injection of MB-1C-OH had no effects in both hot plate and tail flick tests, but produced potent antinociception in the acetic acid-induced writhing test (ED50=0.39 mg/kg), which was antagonized by pretreatment with a selective κ-opioid receptor antagonist Nor-BNI. In the formalin test, subcutaneous injection of MB-1C-OH did not affect the flinching behavior in the first phase, but significantly inhibited that in the second phase (ED50=0.87 mg/kg). In addition, the sedation or depression actions of MB-1C-OH were about 3-fold weaker than those of the classical κ agonist (-)U50,488H.

Conclusion: MB-1C-OH is a novel κ-opioid receptor agonist that produces potent antinociception causing less sedation and depression.
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May 2015

Serine 363 of the {delta}-opioid receptor is crucial for adopting distinct pathways to activate ERK1/2 in response to stimulation with different ligands.

J Cell Sci 2010 Dec 23;123(Pt 24):4259-70. Epub 2010 Nov 23.

State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.

Distinct opioid receptor agonists have been proved to induce differential patterns of ERK activation, but the underlying mechanisms remain unclear. Here, we report that Ser363 in the δ-opioid receptor (δOR) determines the different abilities of the δOR agonists DPDPE and TIPP to activate ERK by G-protein- or β-arrestin-dependent pathways. Although both DPDPE and TIPP activated ERK1/2, they showed different temporal, spatial and desensitization patterns of ERK activation. We show that that DPDPE employed G protein as the primary mediator to activate the ERK cascade in an Src-dependent manner, whereas TIPP mainly adopted a β-arrestin1/2-mediated pathway. Moreover, we found that DPDPE gained the capacity to adopt the β-arrestin1/2-mediated pathway upon Ser363 mutation, accompanied by the same pattern of ERK activation as that induced by TIPP. Additionally, we found that TIPP- but not DPDPE-activated ERK could phosphorylate G-protein-coupled receptor kinase-2 and β-arrestin1. However, such functional differences of ERK disappeared with the mutation of Ser363. Therefore, the present study reveals a crucial role for Ser363 in agonist-specific regulation of ERK activation patterns and functions.
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December 2010