scholarly journals The CXCL12/CXCR4 signaling is required for DPP4 regulation of spontaneous inhibitory postsynaptic currents (sIPSCs)

2020 ◽  
Author(s):  
Yusong Zhang ◽  
Zhiguo Chen ◽  
Zhishan Yang ◽  
Yadi Han
Keyword(s):  
Hippocampal Neurons ◽  
Mean Amplitude ◽  
Gamma Aminobutyric Acid ◽  
Cxcr4 Antagonist ◽  
Inhibitory Postsynaptic Currents ◽  
Cxcr4 Signaling ◽  
Postsynaptic Currents ◽  
The Mean

Abstract Background: Previous data suggested that dipeptidyl peptidase-IV (DPP4) involved in the occurrence of febrile seizure (FS), but its potential mechanism remains to be determined. Here, we investigated whether DPP4 regulated gamma-aminobutyric acid (GABA) mediated spontaneous inhibitory postsynaptic currents (sIPSCs) via the downstream C-X-C Motif Chemokine Ligand 12 (CXCL12)/ C-X-C chemokine receptor type 4 (CXCR4) signaling in cultured hippocampal neurons submitted to hyperthermia(39.5-40°C). Methods: Whole cell patch- clamp method was used to test sIPSC in vitro after DPP4 inhibition or CXCL12 administration. The level of CXCL12 and CXCR4 was tested using western blot analysis. The effect of CXCR4 antagonist AMD3100 (5 mg/ml, i.c.v) on seizures were tested using electroencephalogram (EEG) in a FS model. Results: We found that pharmacological DPP4 inhibitor sitagliptin (Sita,100μM) treatment or siRNA-mediated DPP4 knockdown enhanced the mean amplitude and frequency of sIPSCs in vitro. DPP4 knockdown with siRNA increased protein level of CXCL12 and CXCR4. Furthermore, CXCL12 (10 nM) treatment enhanced inhibitory transmission by increasing the mean frequency and amplitude of sIPSCs in vitro. AMD3100 administration decreased seizure severity by increasing hippocampal GABA content in vivo. Conclusions: Our data suggest that CXCL12/CXCR4 signaling is required for DPP4 regulation of sIPSCs, supporting that DPP4 played a key role in the pathogenesis of FS.

Gabapentin Increases a Tonic Inhibitory Conductance in Hippocampal Pyramidal Neurons

2006 ◽  
Vol 105 (2) ◽  
pp. 325-333 ◽  
Author(s):  
Victor Y. Cheng ◽  
Robert P. Bonin ◽  
Mary W. Chiu ◽  
J Glen Newell ◽  
John F. MacDonald ◽  
...  
Keyword(s):  
Gabaa Receptors ◽  
Hippocampal Neurons ◽  
Gabab Receptors ◽  
Gamma Aminobutyric Acid ◽  
Western Blots ◽  
Inhibitory Postsynaptic Currents ◽  
Postsynaptic Currents ◽  
Inhibitory Conductance ◽  
Tonic Current

Background The mechanisms underlying the therapeutic actions of gabapentin remain poorly understood. The chemical structure and behavioral properties of gabapentin strongly suggest actions on inhibitory neurotransmission mediated by gamma-aminobutyric acid (GABA); however, gabapentin does not directly modulate GABAA or GABAB receptors. Two distinct forms of GABAergic inhibition occur in the brain: postsynaptic conductance and a persistent tonic inhibitory conductance primarily generated by extrasynaptic GABAA receptors. The aim of this study was to determine whether gabapentin increased the tonic conductance in hippocampal neurons in vitro. As a positive control, the effects of vigabatrin, which irreversibly inhibits GABA transaminase, were also examined. Methods GABAA receptors in hippocampal neurons from embryonic mice were studied using whole cell patch clamp recordings. Miniature inhibitory postsynaptic currents and the tonic current were recorded from cultured neurons that were treated for 36-48 h with gabapentin, vigabatrin, or gabapentin and vigabatrin. To determine whether gabapentin increased the expression of GABAA receptors, Western blots were stained with antibodies selective for alpha1, alpha2, and alpha5 subunits. Results GABAA receptors were insensitive to the acute application of gabapentin, whereas chronic treatment increased the amplitude of the tonic current threefold (EC50 = 209 microm) but did not influence miniature inhibitory postsynaptic currents. Vigabatrin increased the tonic conductance, and the maximally effective concentration did not occlude the actions of gabapentin, which suggests that these compounds act by different mechanisms. Neither gabapentin nor vigabatrin increased the expression of GABAA receptors in the neurons. Conclusions Gabapentin increases a tonic inhibitory conductance in mammalian neurons. High-affinity GABAA receptors that generate the tonic conductance may detect small increases in the ambient concentration of neurotransmitter caused by gabapentin.

scholarly journals Regulation of Inhibitory Synaptic Transmission by Vasoactive Intestinal Peptide (VIP) in the Mouse Suprachiasmatic Nucleus

2003 ◽  
Vol 90 (3) ◽  
pp. 1589-1597 ◽  
Author(s):  
Jason Itri ◽  
Christopher S. Colwell
Keyword(s):  
Synaptic Transmission ◽  
Receptor Antagonist ◽  
Kinetic Parameters ◽  
Mean Amplitude ◽  
Dependent Manner ◽  
Patch Clamp Recording ◽  
Inhibitory Synaptic Transmission ◽  
Inhibitory Postsynaptic Currents ◽  
Postsynaptic Currents ◽  
The Mean

Circadian rhythmicity in mammals is generated by a pair of nuclei in the anterior hypothalamus known as the suprachiasmatic nuclei (SCN), whose neurons express a variety of neuropeptides that are thought to play an important role in the circadian timing system. To evaluate the influence of VIP on inhibitory synaptic transmission between SCN neurons, we used whole cell patch-clamp recording in an acute brain slice preparation of mouse SCN. Baseline spontaneous GABAergic inhibitory postsynaptic currents (IPSCs) varied significantly between regions and across phases, with a greater frequency of IPSCs observed in the dorsomedial region during the early night. Bath-applied VIP caused a significant increase in the frequency of spontaneous inhibitory postsynaptic currents (sIPSC) in a reversible and dose-dependent manner with no effect on the mean amplitude or kinetic parameters. The effect of VIP was widespread throughout the SCN and observed in both ventrolateral (VL) and dorsomedial (DM) regions. In the presence of tetrodotoxin, VIP increased the frequency of miniature IPSCs without affecting the mean magnitude or kinetic parameters. The magnitude of the enhancement by VIP was significantly larger during the day than during the night. Pretreatment with the VIP-PACAP receptor antagonist [Ac-Tyr1, D-Phe2]-GHRF 1-29 or the selective VPAC2 receptor antagonist PG 99-465 completely blocked the VIP-induced enhancement. The effect of VIP appears to be mediated by a cAMP/PKA-dependent mechanism as forskolin mimics, while the PKA antagonist H-89 blocks the observed enhancement of GABA currents. Our data suggest that VIP activates presynaptic VPAC2 receptors to regulate inhibitory synaptic transmission within the SCN and that this effect varies from day to night.

Influence of Platelet Membrane Sialic Acid and Platelet-Associated IgG on Ageing and Sequestration of Blood Platelets in Baboons

1993 ◽  
Vol 70 (04) ◽  
pp. 676-680 ◽  
Author(s):  
H F Kotzé ◽  
V van Wyk ◽  
P N Badenhorst ◽  
A du P Heyns ◽  
J P Roodt ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Life Span ◽  
Blood Platelets ◽  
Senescent Cell ◽  
Platelet Membrane ◽  
Antigen Complex ◽  
The Mean ◽  
Aggregation Of Platelets

SummaryPlatelets were isolated from blood of baboons and treated with neuraminidase to remove platelet membrane sialic acid, a process which artificially ages the platelets. The platelets were then labelled with 111In and their mean life span, in vivo distribution and sites of Sequestration were measured. The effect of removal of sialic acid on the attachment of immunoglobulin to platelets were investigated and related to the Sequestration of the platelets by the spleen, liver, and bone marrow. Removal of sialic acid by neuraminidase did not affect the aggregation of platelets by agonists in vitro, nor their sites of Sequestration. The removal of 0.51 (median, range 0.01 to 2.10) nmol sialic acid/108 platelets shortened their life span by 75 h (median, range 0 to 132) h (n = 19, p <0.001), and there was an exponential correlation between the shortening of the mean platelet life span and the amount of sialic acid removed. The increase in platelet-associated IgG was 0.112 (median, range 0.007 to 0.309) fg/platelet (n = 25, p <0.001) after 0.79 (median, range 0.00 to 6.70) nmol sialic acid/108 platelets was removed (p <0.001). There was an exponential correlation between the shortening of mean platelet life span after the removal of sialic acid and the increase in platelet-associated IgG. The results suggest that platelet membrane sialic acid influences ageing of circulating platelets, and that the loss of sialic acid may have exposed a senescent cell antigen that binds IgG on the platelet membrane. The antibody-antigen complex may then provide a signal to the macrophages that the platelet is old, and can be phagocytosed and destroyed.

scholarly journals Formulation and in vitro evaluation of self-nanoemulsifying liquisolid tablets of furosemide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lena Dalal ◽  
Abdul Wahab Allaf ◽  
Hind El-Zein
Keyword(s):  
Theoretical Model ◽  
Castor Oil ◽  
In Vivo Studies ◽  
Coating Materials ◽  
Peg 400 ◽  
The Mean ◽  
Usp Apparatus ◽  
Solid System

AbstractSelf-nanoemulsifying drug delivery systems (SNEDDS) were used to enhance the dissolution rate of furosemide as a model for class IV drugs and the system was solidified into liquisolid tablets. SNEDDS of furosemide contained 10% Castor oil, 60% Cremophor EL, and 30% PEG 400. The mean droplets size was 17.9 ± 4.5 nm. The theoretical model was used to calculate the amounts of the carrier (Avicel PH101) and coating materials (Aerosil 200) to prepare liquisolid powder. Carrier/coating materials ratio of 5/1 was used and Ludipress was added to the solid system, thus tablets with hardness of 45 ± 2 N were obtained. Liquisolid tablets showed 2-folds increase in drug release as compared to the generic tablets after 60 min in HCl 0.1 N using USP apparatus-II. Furosemide loaded SNEDDS tablets have great prospects for further in vivo studies, and the theoretical model is useful for calculating the adequate amounts of adsorbents required to solidify these systems.

Neurotrophic Properties of Silexan, an Essential Oil from the Flowers of Lavender-Preclinical Evidence for Antidepressant-Like Properties

2020 ◽  
Vol 54 (01) ◽  
pp. 37-46
Author(s):  
Kristina Friedland ◽  
Giacomo Silani ◽  
Anita Schuwald ◽  
Carola Stockburger ◽  
Egon Koch ◽  
...  
Keyword(s):  
Essential Oil ◽  
Hippocampal Neurons ◽  
Day Treatment ◽  
Neuronal Cell ◽  
Antidepressant Activity ◽  
In Vivo Models ◽  
Antidepressant Effects ◽  
Primary Hippocampal Neurons

Abstract Background Silexan, a special essential oil from flowering tops of lavandula angustifolia, is used to treat subsyndromal anxiety disorders. In a recent clinical trial, Silexan also showed antidepressant effects in patients suffering from mixed anxiety-depression (ICD-10 F41.2). Since preclinical data explaining antidepressant properties of Silexan are missing, we decided to investigate if Silexan also shows antidepressant-like effects in vitro as well as in vivo models. Methods We used the forced swimming test (FST) in rats as a simple behavioral test indicative of antidepressant activity in vivo. As environmental events and other risk factors contribute to depression through converging molecular and cellular mechanisms that disrupt neuronal function and morphology—resulting in dysfunction of the circuitry that is essential for mood regulation and cognitive function—we investigated the neurotrophic properties of Silexan in neuronal cell lines and primary hippocampal neurons. Results The antidepressant activity of Silexan (30 mg/kg BW) in the FST was comparable to the tricyclic antidepressant imipramine (20 mg/kg BW) after 9-day treatment. Silexan triggered neurite outgrowth and synaptogenesis in 2 different neuronal cell models and led to a significant increase in synaptogenesis in primary hippocampal neurons. Silexan led to a significant phosphorylation of protein kinase A and subsequent CREB phosphorylation. Conclusion Taken together, Silexan demonstrates antidepressant-like effects in cellular as well as animal models for antidepressant activity. Therefore, our data provides preclinical evidence for the clinical antidepressant effects of Silexan in patients with mixed depression and anxiety.

scholarly journals Filociclovir Is an Active Antiviral Agent against Ocular Adenovirus Isolates In Vitro and in the Ad5/NZW Rabbit Ocular Model

2021 ◽  
Vol 14 (4) ◽  
pp. 294
Author(s):  
Eric G. Romanowski ◽  
Islam T. M. Hussein ◽  
Steven C. Cardinale ◽  
Michelle M. Butler ◽  
Lucas R. Morin ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Topical Treatment ◽  
Antiviral Agent ◽  
Human Adenovirus ◽  
Treatment Groups ◽  
Ocular Infections ◽  
The Mean ◽  
Eye Infection

Presently, there is no FDA- or EMA-approved antiviral for the treatment of human adenovirus (HAdV) ocular infections. This study determined the antiviral activity of filociclovir (FCV) against ocular HAdV isolates in vitro and in the Ad5/NZW rabbit ocular model. The 50% effective concentrations (EC50) of FCV and cidofovir (CDV) were determined for several ocular HAdV types using standard plaque reduction assays. Rabbits were topically inoculated in both eyes with HAdV5. On day 1, the rabbits were divided into four topical treatment groups: (1) 0.5% FCV 4x/day × 10 d; (2) 0.1% FCV 4x/day × 10 d; (3) 0.5% CDV 2x/day × 7 d; (4) vehicle 4x/day × 10 d. Eyes were cultured for virus on days 0, 1, 3, 4, 5, 7, 9, 11, and 14. The resulting viral eye titers were determined using standard plaque assays. The mean in vitro EC50 for FCV against tested HAdV types ranged from 0.50 to 4.68 µM, whereas those treated with CDV ranged from 0.49 to 30.3 µM. In vivo, compared to vehicle, 0.5% FCV, 0.1% FCV, and 0.5% CDV produced lower eye titers, fewer numbers of positive eye cultures, and shorter durations of eye infection. FCV demonstrated anti-adenovirus activity in vitro and in vivo.

FKBP51 Modulates Hippocampal Size and Function in Post-translational Regulation of Parkin

2021 ◽  
Author(s):  
Bin Qiu ◽  
Zhaohui Zhong ◽  
Shawn Righter ◽  
Yuxue Xu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Hippocampal Neurons ◽  
Translational Regulation ◽  
Disease Onset ◽  
Fold Increase ◽  
Knock Out ◽  
Fk506 Binding Protein ◽  
Protein Levels ◽  
And Function

Abstract FK506-binding protein 51 (encoded by Fkpb51) has been associated with stress-related mental illness. To identify its function, we studied the morphological consequences of Fkbp51 deletion. Artificial Intelligence-assist morphological analysis identified that Fkbp51 knock-out (KO) mice possess more elongated CA and DG but shorter in height in coronal section when compared to WT. Primary cultured Fkbp51 KO hippocampal neurons were shown to exhibit larger dendritic outgrowth than wild-type (WT) controls, pharmacological manipulation experiments suggest that this may occur through regulation of microtubule-associated protein. Both in vitro primary culture and in vivo labeling support that FKBP51 regulates microtubule-associated protein expression. Furthermore, in the absence of differences in mRNA expression, Fkbp51 KO hippocampus exhibited decreases in βIII-tubulin, MAP2, and Tau protein levels, but a greater than 2.5-fold increase in Parkin protein. Overexpression and knock-down FKBP51 demonstrated that FKBP51 negatively regulates Parkin in a dose-dependent and ubiquitin-mediated manner. These results indicate a potential novel post-translational regulatory of Parkin by FKBP51 and significance of their interaction on disease onset.

Surface culture of Steinernema sp. on two solid media and their pathogenicity against Galleria mellonella

2021 ◽  
Vol 95 ◽  
Author(s):  
C.I. Cortés-Martínez ◽  
A.I. Rodríguez-Hernández ◽  
M.R. López-Cuellar ◽  
N. Chavarría-Hernández
Keyword(s):  
Galleria Mellonella ◽  
Egg Yolk ◽  
Infective Juvenile ◽  
Surface Culture ◽  
Solid Media ◽  
Significant Difference ◽  
Bacterial Lawn ◽  
The Mean

Abstract The use of native entomopathogenic nematodes as biocontrol agents is a strategy to decrease the environmental impact of insecticides and achieve sustainable agriculture crops. In this study, the effect of the surface culture of Steinernema sp. JAP1 over two solid media at 23–27°C on infective juvenile (IJ) production and pathogenicity against Galleria mellonella larvae were investigated. First, the bacterial lawn on the surface of the media with egg yolk (P2) or chicken liver (Cl) were incubated in darkness at 30°C for 48 and 72 h, and 100 surface-sterilized IJs were added. Four harvests were conducted within the next 35 days and the mean accumulated production was superior on Cl (210 × 103 IJs) than on P2 (135 × 103 IJs), but the productivity decreased up to 10% when the incubation time of the bacterial lawn was of 72 h. The mean pathogenicity of in vitro- and in vivo-produced IJs were of 47–64% and 31%, respectively. It is worth noting that none of the two solid media had a statistically significant difference in IJ pathogenicity. Considering that the maximum multiplication factor of IJs on solid media was 2108 and that the pathogenicity against G. mellonella was outstanding, Steinernema sp. has a good potential for in vitro mass production.

Abstract 354: Lower Circulating Levels of Tumor Necrosis Factor Related Apoptosis-inducing Ligand (TRAIL) are Associated with Increased Sub-clinical Coronary Atherosclerosis among Smokers

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Aman Gupta ◽  
Divay Chandra ◽  
Yingze Zhang ◽  
Steven Reis ◽  
Frank Sciurba
Keyword(s):  
Tumor Necrosis Factor ◽  
Coronary Atherosclerosis ◽  
Tumor Necrosis ◽  
Smoking Status ◽  
Calcium Score ◽  
Meso Scale Discovery ◽  
The Mean ◽  
Necrosis Factor

Rationale: There is significant in vitro evidence demonstrating anti-atherogenic effect of circulating Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL). Also, decreased circulating TRAIL levels have been reported in patients with acute myocardial infarction and in those undergoing coronary catheterization due to suspected coronary atherosclerosis. However, it remains unknown if TRAIL levels are associated with sub-clinical coronary atherosclerosis. Methods: The study included 460 current and former smokers enrolled in the Pittsburgh COPD SCCOR study. Serum TRAIL levels were measured by electrochemiluminescence immunoassay, according to the manufacture’s protocol (Meso Scale Discovery, Gaithersburg, Maryland). Coronary atherosclerosis was assessed by a validated visual coronary artery calcium scoring system using non-EKG gated chest CT scans (Weston score). Ordinal logistic regression models were used to identify significant associations between categories of CAC score (0, 1-3, 4-8, and 9-12) and TRAIL level, and to adjust for cardiovascular risk factors. Results: The mean age of the 460 participants was 65.7 ± 6.3 years, 52.2% were male, and the mean pack years of smoking was 55.0 ± 30.8 years. In univariate analyses, each standard deviation decrease in TRAIL levels was associated with 1.42-fold increase in the odds of having calcium scores in one higher category (p<0.001). This association persisted despite adjustment for age, gender, race, body mass index, hypertension, diabetes, hyperlipidemia, pack years of smoking, and current smoking status (adjusted OR for higher category of calcium score per SD decrease in TRAIL level 1.22, p=0.04). Conclusions: Our results expand on the in vitro and in vivo data linking decreased TRAIL levels with increased atherosclerosis by demonstrating a novel association between lower circulating TRAIL and increased subclinical coronary atherosclerosis.

scholarly journals Regulation of GABAergic synapse formation and plasticity by GSK3β-dependent phosphorylation of gephyrin

2010 ◽  
Vol 108 (1) ◽  
pp. 379-384 ◽  
Author(s):  
Shiva K. Tyagarajan ◽  
Himanish Ghosh ◽  
Gonzalo E. Yévenes ◽  
Irina Nikonenko ◽  
Claire Ebeling ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Hippocampal Neurons ◽  
Glycogen Synthase ◽  
Phosphorylation Site ◽  
Scaffolding Protein ◽  
Scaffolding Proteins ◽  
Gabaergic Synapse ◽  
Gabaergic Synapses

Postsynaptic scaffolding proteins ensure efficient neurotransmission by anchoring receptors and signaling molecules in synapse-specific subcellular domains. In turn, posttranslational modifications of scaffolding proteins contribute to synaptic plasticity by remodeling the postsynaptic apparatus. Though these mechanisms are operant in glutamatergic synapses, little is known about regulation of GABAergic synapses, which mediate inhibitory transmission in the CNS. Here, we focused on gephyrin, the main scaffolding protein of GABAergic synapses. We identify a unique phosphorylation site in gephyrin, Ser270, targeted by glycogen synthase kinase 3β (GSK3β) to modulate GABAergic transmission. Abolishing Ser270 phosphorylation increased the density of gephyrin clusters and the frequency of miniature GABAergic postsynaptic currents in cultured hippocampal neurons. Enhanced, phosphorylation-dependent gephyrin clustering was also induced in vitro and in vivo with lithium chloride. Lithium is a GSK3β inhibitor used therapeutically as mood-stabilizing drug, which underscores the relevance of this posttranslational modification for synaptic plasticity. Conversely, we show that gephyrin availability for postsynaptic clustering is limited by Ca2+-dependent gephyrin cleavage by the cysteine protease calpain-1. Together, these findings identify gephyrin as synaptogenic molecule regulating GABAergic synaptic plasticity, likely contributing to the therapeutic action of lithium.

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