scholarly journals Differential Inhibition of Human Nav1.2 Resurgent and Persistent Sodium Currents by Cannabidiol and GS967

2020 ◽  
Vol 21 (7) ◽  
pp. 2454 ◽  
Author(s):  
Emily R. Mason ◽  
Theodore R. Cummins
Keyword(s):  
Antiepileptic Drugs ◽  
Refractory Epilepsy ◽  
Differential Inhibition ◽  
Sodium Currents ◽  
Wild Type ◽  
Human Embryonic Kidney ◽  
Transient Currents ◽  
Persistent Currents ◽  
New Class ◽  
Resurgent Currents

Many epilepsy patients are refractory to conventional antiepileptic drugs. Resurgent and persistent currents can be enhanced by epilepsy mutations in the Nav1.2 channel, but conventional antiepileptic drugs inhibit normal transient currents through these channels, along with aberrant resurgent and persistent currents that are enhanced by Nav1.2 epilepsy mutations. Pharmacotherapies that specifically target aberrant resurgent and/or persistent currents would likely have fewer unwanted side effects and be effective in many patients with refractory epilepsy. This study investigated the effects of cannbidiol (CBD) and GS967 (each at 1 μM) on transient, resurgent, and persistent currents in human embryonic kidney (HEK) cells stably expressing wild-type hNav1.2 channels. We found that CBD preferentially inhibits resurgent currents over transient currents in this paradigm; and that GS967 preferentially inhibits persistent currents over transient currents. Therefore, CBD and GS967 may represent a new class of more targeted and effective antiepileptic drugs.

Effect of Neuroinflammation on ABC Transporters: Possible Contribution to Refractory Epilepsy

2018 ◽  
Vol 17 (10) ◽  
pp. 728-735 ◽  
Author(s):  
Xiaolin Deng ◽  
Yangmei Xie ◽  
Yinghui Chen
Keyword(s):  
Antiepileptic Drugs ◽  
Abc Transporters ◽  
Refractory Epilepsy ◽  
Vascular Endothelial Cells ◽  
Efflux Transporters ◽  
Vascular Endothelial ◽  
Intracellular Signalling Pathways ◽  
The Brain ◽  
Transporter Expression

Background & Objective: Epilepsy is a common and serious chronic neurological disorder that is mainly treated with antiepileptic drugs. Although current antiepileptic drugs used in clinical practice have advanced to the third generation, approximately one-third of patients are refractory to these treatments. More efficacious treatments for refractory epilepsy are therefore needed. A better understanding of the mechanism underlying refractory epilepsy is likely to facilitate the development of a more effective therapy. The abnormal expression and/or dysfunction of efflux transporters, particularly ABC transporters, might contribute to certain cases of refractory epilepsy. Inflammation in the brain has recently been shown to regulate the expression and/or function of ABC transporters in the cerebral vascular endothelial cells and glia of the blood-brain barrier by activating intracellular signalling pathways. Conclusion: Therefore, in this review, we will briefly summarize recent research advances regarding the possible role of neuroinflammation in regulating ABC transporter expression in epilepsy.

scholarly journals First, do no harm: the risks of overtreating children with epilepsy

2007 ◽  
Vol 65 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Eunice Chuang ◽  
Marilisa M. Guerreiro ◽  
Sara Y. Tsuchie ◽  
Angelica Santucci ◽  
Carlos A. M. Guerreiro ◽  
...  
Keyword(s):  
Adverse Events ◽  
Prospective Study ◽  
Antiepileptic Drug ◽  
Antiepileptic Drugs ◽  
Seizure Frequency ◽  
Seizure Control ◽  
Control Method ◽  
Refractory Epilepsy ◽  
Do No Harm ◽  
A Prospective Study

BACKGROUND: Although overtreatment with antiepileptic drugs contributes to the morbidity associated with epilepsy, many children still are overtreated. OBJECTIVE: To evaluate if the withdrawal of at least one antiepileptic drug (AED) in children with refractory epilepsy using polytherapy enable a better seizure control. METHOD: This was a prospective study. Children with refractory epilepsy using at least two AEDs were included. Once the patient, or guardian, agreed to participate in the study, one or more AED were slowly tapered off. The remaining AEDs dosages could be adjusted as needed, but a new AED could not be introduced. RESULTS: Fifteen patients were evaluated, three girls; ages ranging from 3 to 18 (mean=8.7 years). After at least one AED withdrawal, two (13.5%) patients became seizure free, seizures improved >50% in 5 (33.5%) patients, did not change in 5 (33.5%), and seizure frequency became worse in 3 (20%). Adverse events improved in 12 patients (80%). CONCLUSION: The withdrawal of at least one AED is a valuable option in the treatment of selected children with refractory epilepsy.

scholarly journals The expression of wild-type pendrin (SLC26A4) in human embryonic kidney (HEK 293 Phoenix) cells leads to the activation of cationic currents

2005 ◽  
Vol 153 (5) ◽  
pp. 693-699 ◽  
Author(s):  
Silvia Dossena ◽  
Antonella Maccagni ◽  
Valeria Vezzoli ◽  
Claudia Bazzini ◽  
Maria Lisa Garavaglia ◽  
...  
Keyword(s):  
Chloride Transport ◽  
Cellular Systems ◽  
Wild Type ◽  
Human Embryonic Kidney ◽  
Pendred Syndrome ◽  
Patch Clamp Technique ◽  
Chloride Currents ◽  
Hek 293 ◽  
Prelingual Deafness ◽  
Open Question

Objective: The SLC26A4 protein (pendrin) seems to be involved in the exchange of chloride with other anions, therefore being responsible for iodide organification in the thyroid gland and the conditioning of the endolymphatic fluid in the inner ear. Malfunction of SLC26A4 leads to Pendred syndrome, characterized by mild thyroid dysfunction often associated with goiter and/or prelingual deafness. The precise function of the SLC26A4 protein, however, is still elusive. An open question is still whether the SLC26A4-induced ion exchange mechanism is electrogenic or electroneutral. Recently, it has been shown that human pendrin expressed in monkey cells leads to chloride currents. Methods: We overexpressed the human SLC26A4 isoform in HEK293 Phoenix cells and measured cationic and anionic currents by the patch-clamp technique in whole cell configuration. Results: Here we show that human pendrin expressed in human cells does not lead to the activation of chloride currents, but, in contrast, leads to an increase of cationic currents. Conclusion: Our experiments suggest that the SLC26A4-induced chloride transport is electroneutral when expressed in human cellular systems.

A new class of mutations in Arabidopsis thaliana, acaulis1, affecting the development of both inflorescences and leaves

Development ◽  
1993 ◽  
Vol 118 (3) ◽  
pp. 751-764 ◽  
Author(s):  
H. Tsukaya ◽  
S. Naito ◽  
G. P. Redei ◽  
Y. Komeda
Keyword(s):  
Arabidopsis Thaliana ◽  
Apical Meristem ◽  
Developmental Stages ◽  
Temperature Shift ◽  
Wild Type ◽  
New Class ◽  
Group 4 ◽  
Consequent Reduction ◽  
In The Wild ◽  
Specific Temperature

We isolated and analyzed mutants of Arabidopsis thaliana, acaulis, with flower stalks that are almost absent or are much reduced in length. The mutations are divided between two loci, acaulis1 (acl1) and acaulis2 (acl2). The acl1-1 mutation has been assigned to linkage group 4 in the vicinity of locus ap2. The acl1-1 mutant showed premature arrest of the inflorescence meristem after the onset of reproductive development, followed by consequent reduction in the number of flower-bearing phytomers and therefore flowers. The apical meristem of the inflorescences was morphologically normal but its radius was about half that of the wild type. The acl1 mutants are also defective in the development of foliage leaves. Both defects could be rescued by growth at a specific temperature (28°C). The length of the cells in acl1-3 mutant was less than that in the wild type but the numbers of cells in leaves and internodes of acl1 mutants were calculated to be the same as those of the wild type. Thus, the defects in inflorescences and leaves were attributed to defects in the process of elongation (maturation) of these cells. Temperature-shift experiments showed that the Acl1+ product was necessary at all developmental stages. A critical stage was shown to exist for recovery from the cessation of development of inflorescence meristems that was caused by the acl1-1 mutation. Grafting experiments showed that the acl1-1 mutation does not affect diffusible substances. An analysis of double mutants carrying both acl1-1 and one of developmental mutations, ap1, clv1, lfy, or tfl1, showed that ACL1 is a new class of gene.

scholarly journals Lys694Arg polymorphism leads to blunted responses to LPS by interfering TLR4 with recruitment of MyD88

2020 ◽  
pp. 175342592092747
Author(s):  
Yajie Yang ◽  
Yan Hu ◽  
Yile Zhou ◽  
Tao Liang ◽  
Haihong Tang ◽  
...  
Keyword(s):  
Inflammatory Factors ◽  
Myeloid Differentiation ◽  
Study Group ◽  
Tlr4 Expression ◽  
Wild Type ◽  
Human Embryonic Kidney ◽  
Gram Negative ◽  
Tnf Α ◽  
Polymorphic Variants ◽  
Myeloid Differentiation Factor

TLR4 polymorphisms such as Asp299Gly and Thr399Ile related to Gram-negative sepsis have been reported to result in significantly blunted responsiveness to LPS. Our study group previously screened other TLR4 polymorphic variants by checking the NF-κB activation in comparison to wild type (WT) TLR4 in human embryonic kidney 293T cells. In this study, we found that the Lys694Arg (K694R) polymorphism reduced the activation of NF-κB, and the production of downstream inflammatory factors IL-1, TNF-α and IL-6, representing the K694R polymorphism, led to blunted responsiveness to LPS. Then, we examined the influence of the K694R polymorphism on total and cell-surface TLR4 expression by Western blotting and flow cytometry, respectively, but observed no differences between the K694R polymorphism and WT TLR4. We also used co-immunoprecipitation to determine the interaction of the K694R polymorphism and WT TLR4 with their co-receptor myeloid differentiation factor 2 (MD2) and their downstream signal adaptor MyD88. We found that K694R reduced the recruitment of MyD88 in TLR4 signalling but had no impact on the interaction with MD2.

scholarly journals In Vivo Dimerization of Types 1, 2, and 3 Iodothyronine Selenodeiodinases

Endocrinology ◽  
2003 ◽  
Vol 144 (3) ◽  
pp. 937-946 ◽  
Author(s):  
Cyntia Curcio-Morelli ◽  
Balazs Gereben ◽  
Ann Marie Zavacki ◽  
Brian W. Kim ◽  
Stephen Huang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Western Blot ◽  
Relative Molecular Mass ◽  
Disulfide Bridges ◽  
Wild Type ◽  
Human Embryonic Kidney ◽  
Cell Lysate ◽  
Sds Page ◽  
Catalytically Active

The goal of the present investigation was to test the hypothesis that types 1, 2, and 3 iodothyronine selenodeiodinases (D1, D2, and D3) can form homodimers. The strategy included transient coexpression of wild-type (wt) deiodinases (target), and FLAG-tagged alanine or cysteine mutants (bait) in human embryonic kidney epithelial cells. SDS-PAGE of the immunoprecipitation pellet of 75Se-labeled cell lysates using anti-FLAG antibody revealed bands of the correct sizes for the respective wt enzymes, which corresponded to approximately 2–5% of the total deiodinase protein in the cell lysate. Western blot analysis with anti-FLAG antibody of lysates of cells transiently expressing individual FLAG-tagged-cysteine deiodinases revealed specific monomeric bands for each deiodinase and additional minor bands of relative molecular mass (Mr) of 55,000 for D1, Mr 62,000 for D2, and Mr 65,000 for D3, which were eliminated by 100 mm dithiothreitol at 100 C. Anti-FLAG antibody immunodepleted 10% of D1 and 38% of D2 activity from lysates of cells coexpressing inactive FLAG-tagged Ala mutants and the respective wt enzymes (D1 or D2) but failed to immunodeplete wtD3 activity. D1 or D2 activities were present in these respective pellets. We conclude 1) that overexpressed selenodeiodinases can homodimerize probably through disulfide bridges; and 2) at least for D1 and D2, monomeric forms are catalytically active, demonstrating that only one wt monomer partner is required for catalytic activity of these two deiodinases.

Strain construction for enhanced production of spinosad via intergeneric protoplast fusion

2009 ◽  
Vol 55 (9) ◽  
pp. 1070-1075 ◽  
Author(s):  
Chao Wang ◽  
XiaoLin Zhang ◽  
Zhi Chen ◽  
Ying Wen ◽  
Yuan Song
Keyword(s):  
Protoplast Fusion ◽  
Wild Type Strain ◽  
Molecular Genetic ◽  
Industrial Applications ◽  
Streptomyces Avermitilis ◽  
Wild Type ◽  
Saccharopolyspora Spinosa ◽  
New Class ◽  
Enhanced Production ◽  
Microbial Strains

Spinosad is a new class of insecticides produced by Saccharopolyspora spinosa . The aim of this study was to construct a starch-utilizing strain that overproduced spinosad by intergeneric fusion between S. spinosa and Streptomyces avermitilis . Protoplast fusion is an important technique for engineering microbial strains, especially for microorganisms with few available molecular genetic tools. Protoplast fusion was conducted with UV-irradiated protoplasts of S. spinosa and S. avermitilis. Among 76 recombinants screened by ESI-MS and HPLC, a starch-utilizing strain F17, identified as S. spinosa, was obtained. The yield of spinosad in F17 was increased by 447.22%, compared with the yield of the wild-type strain. This is the first report of intergeneric protoplast fusion between S. spinosa and S. avermilitis, which shows great potential for industrial applications.

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