sl-327 and Disease-Models--Animal

Tracheal stenosis is a refractory and recurrent disease induced by excessive cell proliferation within the restricted tracheal space. We investigated the role of extracellular signal-regulated kinase (ERK), which mediates a broad range of intracellular signal transduction processes in tracheal stenosis and the therapeutic effect of the MEK inhibitor which is the upstream kinase of ERK. We histologically analyzed cauterized tracheas to evaluate stenosis using a tracheal stenosis mouse model. Using Western blot, we analyzed the phosphorylation rate of ERK1/2 after cauterization with or without MEK inhibitor. MEK inhibitor was intraperitoneally injected 30 min prior to cauterization (single treatment) or 30 min prior to and 24, 48, 72, and 96 hours after cauterization (daily treatment). We compared the stenosis of non-inhibitor treatment, single treatment, and daily treatment group. We successfully established a novel mouse model of tracheal stenosis. The cauterized trachea increased the rate of stenosis compared with the normal control trachea. The phosphorylation rate of ERK1 and ERK2 was significantly increased at 5 min after the cauterization compared with the normal controls. After 5 min, the rates decreased over time. The daily treatment group had suppressed stenosis compared with the non-inhibitor treatment group. p-ERK1/2 activation after cauterization could play an important role in the tracheal wound healing process. Consecutive inhibition of ERK phosphorylation is a potentially useful therapeutic strategy for tracheal stenosis.

Topics: Aminoacetonitrile; Animals; Cell Proliferation; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation, Enzymologic; Male; Mice; Mice, Inbred C57BL; Phosphorylation; Protease Inhibitors; Signal Transduction; Tracheal Stenosis

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

Topics: Aminoacetonitrile; Animals; Cells, Cultured; Cerebral Cortex; Disease Models, Animal; Embryo, Mammalian; Female; GABAergic Neurons; Humans; Interneurons; LIM-Homeodomain Proteins; MAP Kinase Signaling System; Median Eminence; Mice; Mice, Knockout; Nerve Tissue Proteins; Neurofibromatosis 1; Neurofibromin 1; Neuroglia; Parvalbumins; Primary Cell Culture; ras GTPase-Activating Proteins; Somatostatin; Transcription Factors

The role of the mechanistic target of rapamycin (mTOR) signaling in the antidepressant effects of ketamine is controversial. In addition to mTOR, extracellular signal-regulated kinase (ERK) is a key signaling molecule in prominent pathways that regulate protein synthesis. (R)-Ketamine has a greater potency and longer-lasting antidepressant effects than (S)-ketamine. Here we investigated whether mTOR signaling and ERK signaling play a role in the antidepressant effects of two enantiomers.. The effects of mTOR inhibitors (rapamycin and AZD8055) and an ERK inhibitor (SL327) on the antidepressant effects of ketamine enantiomers in the chronic social defeat stress (CSDS) model (n = 7 or 8) and on those of ketamine enantiomers in these signaling pathways in mouse brain regions were examined.. The intracerebroventricular infusion of rapamycin or AZD8055 blocked the antidepressant effects of (S)-ketamine, but not (R)-ketamine, in the CSDS model. Furthermore, (S)-ketamine, but not (R)-ketamine, significantly attenuated the decreased phosphorylation of mTOR and its downstream effector, ribosomal protein S6 kinase, in the prefrontal cortex of susceptible mice after CSDS. Pretreatment with SL327 blocked the antidepressant effects of (R)-ketamine but not (S)-ketamine. Moreover, (R)-ketamine, but not (S)-ketamine, significantly attenuated the decreased phosphorylation of ERK and its upstream effector, mitogen-activated protein kinase/ERK kinase, in the prefrontal cortex and hippocampal dentate gyrus of susceptible mice after CSDS.. This study suggests that mTOR plays a role in the antidepressant effects of (S)-ketamine, but not (R)-ketamine, and that ERK plays a role in (R)-ketamine's antidepressant effects. Thus, it is unlikely that the activation of mTOR signaling is necessary for antidepressant actions of (R)-ketamine.

Topics: Aminoacetonitrile; Animals; Antidepressive Agents; Brain; Chronic Disease; Depressive Disorder; Disease Models, Animal; Dominance-Subordination; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Ketamine; Male; Mice, Inbred C57BL; Morpholines; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; Sirolimus; Stress, Psychological; TOR Serine-Threonine Kinases

Recently, we demonstrated that inhibition of ERK1/2 activity by SL-327 treatment blocks seizure behavior in Krushinsky-Molodkina (KM) rats, which was mediated by altering of GABA and glutamate release mechanism in the hippocampus. Basal ganglia representing various subcortical cell groups play a significant role in the regulation of motor activity, including epileptiform seizures..  To verify if nigrostriatal system could be also affected by SL-327 treatment we analyzed the expression of tyrosine hydroxylase, D1 and D2 dopamine receptors, NR2B subunit of NMDA receptor as well as vesicular glutamate transporter VGLUT2 and glutamic acid decarboxylases GAD65/67 in the striatum and substantia nigra of KM rats.. Animals were injected i.p. with SL-327 (50 mg/kg) 60 min before audio stimulation. After audiogenic stimulation the brains of control and SL 327 treated rats were removed for further immunohistochemical and biochemical analysis..  Obtained results demonstrated a decrease activity in synapsin I, and accumulation of VGLUT2 in the striatum after blockade of audiogenic seizure (AGS) by SL 327 that could lead to inhibition of glutamate release. While in the striatum GAD65/67 level was diminished, in the substantia nigra GAD65/67 was increased showing enhanced inhibitory output to the compact part of the substantia nigra. Analysis of dopaminergic system showed a significant reduction of tyrosine hydroxylase activity and expression in the substantia nigra, and decreased D1 and D2 receptor expression in the striatum. In summary, we propose that changes in the nigrostriatal system could be mediated by inhibitory effect of SL 327 on AGS expression.

Topics: Acoustic Stimulation; Aminoacetonitrile; Animals; Auditory Perception; Corpus Striatum; Disease Models, Animal; Female; gamma-Aminobutyric Acid; Glutamic Acid; Male; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Neurons; Protein Kinase Inhibitors; Rats; Seizures; Substantia Nigra; Synapsins

A previous study found that the antidepressant-like effects of ethanolic extracts from Hemerocallis citrina are predominantly related to the flavonoid, hesperidin. The study herein aimed to explore the antidepressant-like mechanism of hesperidin in mice induced by chronic mild stress (CMS). The results indicated that hesperidin reversed the reduction of sucrose preference and the elevation of immobility time in mice induced by CMS. In addition, the increase in serum corticosterone levels and decrease in hippocampal extracellular signal-regulated kinase (ERK) phosphorylation and brain-derived neurotrophic factor (BDNF) levels in CMS mice were also ameliorated by hesperidin treatment. In contrast, improvement by hesperidin was suppressed by pretreatment with ERK inhibitor SL327. Taken together, our findings confirmed the antidepressant-like effect of hesperidin and indicated that hesperidin-induced BDNF up-regulation was mediated in an ERK-dependent manner.

Topics: Aminoacetonitrile; Animals; Antidepressive Agents; Brain-Derived Neurotrophic Factor; Corticosterone; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Food Deprivation; Food Preferences; Gene Expression Regulation; Hesperidin; Hippocampus; Male; Mice; Mice, Inbred ICR; Phosphorylation; Protease Inhibitors; Stress, Psychological; Sucrose

The potential antidepressant effects of curcumin have been demonstrated in various animal models of depression, however, there is little information regarding the site and mechanisms of curcumin in promoting antidepressant effects. The present study attempts to explore the mechanisms underlying the antidepressant-like action of curcumin by measuring the contents of brain derived neurotrophic factor (BDNF) in the amygdala of animal model of depression. The results showed that treatment with curcumin (40 mg/kg, i.p.) significantly reduced depressive-like behaviors of mice in the forced swim test. Chronic administration of curcumin (40 mg/kg, i.p., 21 days) increased BDNF protein levels in the amygdala and this enhancement was suppressed by pretreatment with the extracellular signal-regulated kinase (ERK) inhibitor SL327. Additionally, the increased levels of ERK phosphoryation in the amygdala by curcumin were blocked by the ERK inhibitor, and inhibition of this kinase prevented the antidepressant effects of curcumin. All of these effects of curcumin, were essentially identical to that observed with the clinical antidepressant, fluoxetine. These results suggest that the antidepressant-like effects of curcumin in the forced swim test are mediated, at least in part, by an ERK-regulated increase of BDNF expression in the amygdala of mice.

Topics: Aminoacetonitrile; Amygdala; Animals; Antidepressive Agents; Brain-Derived Neurotrophic Factor; Curcumin; Depression; Disease Models, Animal; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation; Male; MAP Kinase Signaling System; Mice; Mice, Inbred C57BL; Phosphorylation

Although extracellular signal-regulated kinase (ERK) activity is essential for the acquisition of a variety of associative learning tasks, its involvement in the acquisition and extinction of ethanol (EtOH)-induced conditioned place preference (CPP) remains unknown. Therefore, in these experiments we examined the effects of the ERK-kinase (MEK)-inhibitor SL327 on acquisition and expression of EtOH-CPP as well as the dose- and time-dependent effects of SL327 on CPP extinction. The parametric findings of Experiment 1 showed that three 30-min (but not 15- or 5-min) non-reinforced trials were required to completely extinguish EtOH-CPP in male, DBA/2J mice. In Experiments 2 and 3, SL327 (30 and 50mg/kg), administered 30 or 90min prior to extinction trials, was unable to impair EtOH-CPP extinction. Experiment 4 showed that SL327 (50mg/kg) had no effect on acquisition of EtOH-CPP or the development of EtOH-induced sensitization during conditioning. When administered prior to testing in Experiments 5 and 6, SL327 did not alter expression of EtOH-CPP but did reduce test activity. Importantly, SL327 significantly reduced pERK protein levels when assessed in the dorsal striatum and motor cortex (Experiment 7). Together, these data suggest that EtOH-related learning and EtOH reward in mice, as assessed with CPP, are not impaired by the systemically administered MEK-inhibitor SL327.

Topics: Aminoacetonitrile; Analysis of Variance; Animals; Behavior, Animal; Central Nervous System Depressants; Conditioning, Operant; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Interactions; Drug-Seeking Behavior; Enzyme Inhibitors; Ethanol; Extinction, Psychological; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation, Enzymologic; Male; Mice; Mice, Inbred DBA; Reinforcement, Psychology; Signal Transduction; Time Factors

Treatment of Parkinson disease (PD) with L-3,4-dihydroxyphenylalanine (L-DOPA) dramatically relieves associated motor deficits, but L-DOPA-induced dyskinesias (LID) limit the therapeutic benefit over time. Previous investigations have noted changes in striatal medium spiny neurons, including abnormal activation of extracellular signal-regulated kinase1/2 (ERK). Using two PD models, the traditional 6-hydroxydopamine toxic lesion and a genetic model with nigrostriatal dopaminergic deficits, we found that acute dopamine challenge induces ERK activation in medium spiny neurons in denervated striatum. After repeated L-DOPA treatment, however, ERK activation diminishes in medium spiny neurons and increases in striatal cholinergic interneurons. ERK activation leads to enhanced basal firing rate and stronger excitatory responses to dopamine in striatal cholinergic neurons. Pharmacological blockers of ERK activation inhibit L-DOPA-induced changes in ERK phosphorylation, neuronal excitability, and the behavioral manifestation of LID. In addition, a muscarinic receptor antagonist reduces LID. These data indicate that increased dopamine sensitivity of striatal cholinergic neurons contributes to the expression of LID, which suggests novel therapeutic targets for LID.

Topics: Adenosine A2 Receptor Antagonists; Aminoacetonitrile; Animals; Aphakia; Choline O-Acetyltransferase; Cholinergic Fibers; Disease Models, Animal; Dopamine; Dyskinesias; Gene Expression Regulation; Homeodomain Proteins; Levodopa; Mice; Mice, Transgenic; Neurons; Parkinson Disease; Phosphorylation; Transcription Factors

Restraining the toxic pathways of amyloid beta peptide (Abeta) by daily supplementation with dietary products has been shown effective in preventing cognitive decline. In this study, we examined the effects of the orally administered Leu-Ile, a hydrophobic dipeptide, on the neurotoxicity of Abeta(25-35) in mice. Chronic daily treatment with Leu-Ile prevented the Abeta(25-35)-induced protein nitration and impairment of novel object recognition memory in mice. Protein nitration in the hippocampus induced by Abeta(25-35) was associated with the hyperphosphorylation of extracellular signal-regulated kinase (ERK) which was found responsible for the over-expression of inducible nitric oxide synthase. Sub-chronic treatment with Leu-Ile prevented the Abeta(25-35)-induced hyperphosphorylation of ERK and protein nitration in the hippocampus. The results suggested that with the protective property against the neurotoxicity of Abeta(25-35), Leu-Ile could be considered as a candidate for the dietary supplementation in the prevention of Abeta-related impairment of recognition memory.

Topics: Administration, Oral; Aminoacetonitrile; Amyloid beta-Peptides; Animals; Brain-Derived Neurotrophic Factor; Disease Models, Animal; Enzyme Inhibitors; Exploratory Behavior; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation; Hippocampus; Isoleucine; Leucine; Male; Memory Disorders; Mice; Mice, Inbred ICR; Nitric Oxide Synthase Type II; Oligopeptides; Peptide Fragments; Phosphorylation; Recognition, Psychology; Time Factors

Angiogenesis occurs in the brains of Parkinson's disease patients, but the effects of dopamine replacement therapy on this process have not been examined. Using rats with 6-hydroxydopamine lesions, we have compared angiogenic responses induced in the basal ganglia by chronic treatment with either L-DOPA, or bromocriptine, or a selective D1 receptor agonist (SKF38393). Moreover, we have asked whether L-DOPA-induced angiogenesis can be blocked by co-treatment with either a D1- or a D2 receptor antagonist (SCH23390 and eticlopride, respectively), or by an inhibitor of extracellular signal-regulated kinases 1 and 2 (ERK1/2) (SL327). L-DOPA, but not bromocriptine, induced dyskinesia, which was associated with endothelial proliferation, upregulation of immature endothelial markers (nestin) and downregulation of endothelial barrier antigen in the striatum and its output structures. At a dose inducing dyskinesia (1.5 mg/kg/day), SKF38393 elicited angiogenic changes similar to L-DOPA. Antagonism of D1- but not D2 class receptors completely suppressed both the development of dyskinesia and the upregulation of angiogenesis markers. In fact, L-DOPA-induced endothelial proliferation was markedly exacerbated by low-dose D2 antagonism (0.01 mg/kg eticlopride). Inhibition of ERK1/2 by SL327 attenuated L-DOPA-induced dyskinesia and completely inhibited all markers of angiogenesis. These results highlight the specific link between treatment-induced dyskinesias and microvascular remodeling in the dopamine-denervated brain. L-DOPA-induced angiogenesis requires stimulation of D1 receptors and activation of ERK1/2, whereas the stimulation of D2 receptors seems to oppose this response.

Topics: 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; Aminoacetonitrile; Animals; Antiparkinson Agents; Basal Ganglia; Benzazepines; Bromocriptine; Disease Models, Animal; Dopamine Agents; Dopamine D2 Receptor Antagonists; Extracellular Signal-Regulated MAP Kinases; Female; Levodopa; Neovascularization, Pathologic; Oxidopamine; Parkinsonian Disorders; Protease Inhibitors; Rats; Rats, Sprague-Dawley; Receptors, Dopamine D1; Receptors, Dopamine D2; Salicylamides

Our previous studies have shown that morphine withdrawal induced hyperactivity of cardiac noradrenergic pathways. The purpose of the present study was to evaluate the effects of morphine withdrawal on site-specific phosphorylation of TH in the heart.. Dependence on morphine was induced by a 7-day s.c. implantation of morphine pellets in rats. Morphine withdrawal was precipitated on day 8 by an injection of naloxone (2 mg kg(-1)). TH phosphorylation was determined by quantitative blot immunolabelling using phosphorylation state-specific antibodies.. Naloxone-induced morphine withdrawal induced phosphorylation of TH at serine (Ser)40 and Ser31 in the right ventricle, associated with both an increase in total TH levels and an enhancement of TH activity. When HA-1004 (PK A inhibitor) was infused, concomitantly with morphine, it diminished the increase in noradrenaline turnover, total TH levels and TH phosphorylation at Ser40 in morphine-withdrawn rats. In contrast, the infusion of calphostin C (PKC inhibitor), did not modify the morphine withdrawal-induced increase in noradrenaline turnover and total TH levels. In addition, we show that the ability of morphine withdrawal to stimulate phosphorylation at Ser31 was reduced by SL327, an inhibitor of ERK 1/2 activation.. The present findings demonstrate that the enhancement of total TH levels and the increased phosphorylation state of TH during morphine withdrawal were dependent on PKA and ERK activities and suggest that these transduction pathways might contribute to the activation of the cardiac catecholaminergic neurons in response to morphine withdrawal.

Topics: Aminoacetonitrile; Animals; Cyclic AMP-Dependent Protein Kinases; Disease Models, Animal; Drug Implants; Isoquinolines; Male; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Morphine; Morphine Dependence; Myocardium; Naloxone; Naphthalenes; Narcotic Antagonists; Norepinephrine; Phosphorylation; Protein Kinase C-delta; Protein Kinase Inhibitors; Rats; Rats, Sprague-Dawley; Serine; Substance Withdrawal Syndrome; Sulfonamides; Tyrosine 3-Monooxygenase

The aim of this study was to determine whether inhibition of the extracellular-regulated kinase signaling pathway decreases acute amphetamine-induced behavioral activity and neuropeptide gene expression in the rat striatum. Western blotting revealed that extracellular-regulated kinase1/2 phosphorylation was highly induced in the rat striatum 15 min after an acute amphetamine (2.5 mg/kg, i.p.) injection without altering the total amount of extracellular-regulated kinase protein. In a separate experiment, the systemic injection of SL327, a selective inhibitor of extracellular regulated kinase kinase that crosses the blood-brain barrier, 1 h prior to amphetamine administration decreased amphetamine-induced vertical and horizontal activity. Quantitative in situ hybridization histochemistry showed that SL327 abolished the high levels of preproenkephalin and preprodynorphin mRNA induced by amphetamine in the striatum with no alteration of their basal levels. In another set of experiments, the hyperlocomotor activity induced by amphetamine was reduced by pretreatment with intra-striatal infusion of U0126. U0126 also blocked the amphetamine-induced increases in phospho-extracellular-regulated kinase and preproenkephalin and preprodynorphin gene expression in the striatum. These data indicate that activation of the extracellular-regulated kinase cascade contributes to the behavioral effects and changes in striatal neuropeptide gene expression induced by acute amphetamine.

Topics: Aminoacetonitrile; Amphetamine; Amphetamine-Related Disorders; Animals; Butadienes; Corpus Striatum; Disease Models, Animal; Dynorphins; Enkephalins; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation; Male; MAP Kinase Signaling System; Motor Activity; Neuropeptides; Nitriles; Phosphorylation; Protein Precursors; Rats; Rats, Sprague-Dawley; RNA, Messenger; Up-Regulation

Pilocarpine-induced seizures are mediated by the M(1) subtype of muscarinic acetylcholine receptor (mAChR), but little is known about the signaling mechanisms linking the receptor to seizures. The extracellular signal-regulated kinase (ERK) signaling cascade is activated by M(1) mAChR and is elevated during status epilepticus. Yet, the role of ERK activation prior to seizure has not been evaluated. Here, we examine the role of pilocarpine-induced ERK activation in the induction of seizures in mice by pharmacological and behavioral approaches. We show that pilocarpine induces ERK activation prior to the induction of seizures by both western blot and immunocytochemistry with an antibody to phosphorylated ERK. In addition, we show that the ERK pathway inhibitor SL327 effectively blocks the pilocarpine-induced ERK activation. However, SL327 pretreatment has no effect on the initiation of seizures. In fact, animals treated with SL327 had higher seizure-related mortality than vehicle-treated animals, suggesting activated ERK may serve a protective role during seizures. In addition, ERK inhibition had no effect on the development of the long-term sequelae of status epilepticus (SE), including mossy fiber sprouting, neuronal death and spontaneous recurrent seizures.

Topics: Aminoacetonitrile; Animals; Blotting, Western; Cell Death; Disease Models, Animal; Enzyme Activation; Enzyme Inhibitors; Immunohistochemistry; Mice; Mice, Inbred C57BL; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Mossy Fibers, Hippocampal; Neurons; Pilocarpine; Protease Inhibitors; Receptors, Muscarinic; Recurrence; Seizures; Status Epilepticus; Survival Rate