scholarly journals hERG Channel-Related Cardiotoxicity Assessment of 13 Herbal Medicines

2021 ◽  
Vol 42 (3) ◽  
pp. 44-55
Author(s):  
Hyekyung Ha ◽  
Sion Lee ◽  
Dong-Hyun Kim ◽  
Chang-Seob Seo ◽  
Hyeun-kyoo Shin
Keyword(s):  
Potassium Channel ◽  
Cardiac Arrhythmia ◽  
Herbal Medicines ◽  
Positive Control ◽  
Medicinal Products ◽  
Drug Induced ◽  
Hek 293 ◽  
293 Cells ◽  
Major Factors ◽  
Corydalis Tuber

Objectives: As the use of herbal medicinal products (HMPs) increases worldwide, systematic verification of the safety of HMPs is required. The induction of cardiotoxicity is one of the major factors in post-approval withdrawal of medicinal products, and drug-induced cardiotoxicity assessment is emerging as an important step in drug development. In the present study, we evaluated human ether-à-go-go-related gene (hERG) potassium channel-related cardiotoxicity to predict the risk of cardiac arrhythmia in thirteen herbal medicines known to have cardiac toxicity. Methods: We measured the inhibition rate of hERG potassium channel activity of 13 medicinal herbal extracts in hERG-expressing HEK 293 cells using an automated patch-clamping system. Quinidine was used as a positive control for inhibition of hERG activity. Results: Extracts of Evodiae Fructus, Strychni Semen, and Corydalis Tuber potently inhibited the activity of hERG, and IC<sub>50</sub> values were 3.158, 19.87, and 41.26 <i>μ</i>g/mL, respectively. Cnidi Fructus, Ephedra Herba, Lithospermi Radix, Polygoni Multiflori Radix, Visci Ramulus et Folium, Asiasari Radix et Rhizoma, and Scolopendra weakly inhibited hERG activity, and the IC<sub>50</sub> value for each herbal medicine was more than 400 <i>μ</i>g/mL. Aconiti Kusnezoffii Tuber and two types of Aconiti Lateralis Radix Preparata (Po and Yeom) had weak inhibitory activity against hERG, and the IC<sub>50</sub> values were more than 700 <i>μ</i>g/mL. The IC<sub>50</sub> value of quinidine against hERG was 1.021 <i>μ</i>M. Conclusion: Evodiae Fructus, Strychni Semen, and Corydalis Tuber acted as potent inhibitors against hERG. These herbal medicines may cause cardiac arrhythmia through QT prolongation, so care should be taken when taking them.

scholarly journals Drug-Induced Lysosomal Impairment Is Associated with the Release of Extracellular Vesicles Carrying Autophagy Markers

2021 ◽  
Vol 22 (23) ◽  
pp. 12922
Author(s):  
Krizia Sagini ◽  
Sandra Buratta ◽  
Federica Delo ◽  
Roberto Maria Pellegrino ◽  
Stefano Giovagnoli ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Morphological Changes ◽  
The Body ◽  
Medium Size ◽  
Drug Induced ◽  
Hek 293 ◽  
293 Cells ◽  
Amiodarone Treatment ◽  
Lysosomal System

Amiodarone is a cationic amphiphilic drug used as an antiarrhythmic agent. It induces phospholipidosis, i.e., the accumulation of phospholipids within organelles of the endosomal–lysosomal system. Extracellular vesicles (EVs) are membrane-enclosed structures released by any type of cell and retrieved in every fluid of the body. EVs have been initially identified as a system to dispose cell waste, but they are also considered to be an additional manner to transmit intercellular signals. To understand the role of EVs in drug-induced phospholipidosis, we investigated EVs release in amiodarone-treated HEK-293 cells engineered to produce fluorescently labelled EVs. We observed that amiodarone induces the release of a higher number of EVs, mostly of a large/medium size. EVs released upon amiodarone treatment do not display significant morphological changes or altered size distribution, but they show a dose-dependent increase in autophagy associated markers, indicating a higher release of EVs with an autophagosome-like phenotype. Large/medium EVs also show a higher content of phospholipids. Drugs inducing lysosomal impairment such as chloroquine and bafilomycin A1 similarly prompt a higher release of EVs enriched in autophagy markers. This result suggests a mechanism associated with amiodarone-induced lysosomal impairment more than a connection with the accumulation of specific undigested substrates. Moreover, the implementation of the lysosomal function by overexpressing TFEB, a master gene regulator of lysosomal biogenesis, prevents the amiodarone-induced release of EVs, suggesting that this could be a feasible target to attenuate drug-induced abnormalities.

Tyrosine Phosphorylation Modulates Current Amplitude and Kinetics of a Neuronal Voltage-Gated Potassium Channel

1997 ◽  
Vol 78 (3) ◽  
pp. 1563-1573 ◽  
Author(s):  
Debra A. Fadool ◽  
Todd C. Holmes ◽  
Kevin Berman ◽  
Daniel Dagan ◽  
Irwin B. Levitan
Keyword(s):  
Tyrosine Kinase ◽  
Potassium Channel ◽  
Tyrosine Phosphorylation ◽  
Current Amplitude ◽  
Hek 293 ◽  
Voltage Gated ◽  
Tyrosine Residues ◽  
Channel Protein ◽  
293 Cells ◽  
Kinetics Of

Fadool, Debra A., Todd C. Holmes, Kevin Berman, Daniel Dagan, and Irwin B. Levitan. Tyrosine phosphorylation modulates current amplitude and kinetics of a neuronal voltage-gated potassium channel. J. Neurophysiol. 78: 1563–1573, 1997. The modulation of the Kv1.3 potassium channel by tyrosine phosphorylation was studied. Kv1.3 was expressed in human embryonic kidney (HEK 293) cells, and its activity was measured by cell-attached patch recording. The amplitude of the characteristic C-type inactivating Kv1.3 current is reduced by >95%, in all cells tested, when the channel is co-expressed with the constitutively active nonreceptor tyrosine kinase, v-Src. This v-Src–induced suppression of current is accompanied by a robust tyrosine phosphorylation of the channel protein. No suppression of current or tyrosine phosphorylation of Kv1.3 protein is observed when the channel is co-expressed with R385A v-Src, a mutant with severely impaired tyrosine kinase activity. v-Src–induced suppression of Kv1.3 current is relieved by pretreatment of the HEK 293 cells with two structurally different tyrosine kinase inhibitors, herbimycin A and genistein. Furthermore, Kv1.3 channel protein is processed properly and targeted to the plasma membrane in v-Src cotransfected cells, as demonstrated by confocal microscopy using an antibody directed against an extracellular epitope on the channel. Thus v-Src–induced suppression of Kv1.3 current is not mediated through decreased channel protein expression or interference with its targeting to the plasma membrane. v-Src co-expression also slows the C-type inactivation and speeds the deactivation of the residual Kv1.3 current. Mutational analysis demonstrates that each of these modulatory changes, in current amplitude and kinetics, requires the phosphorylation of Kv1.3 at multiple tyrosine residues. Furthermore, a different combination of tyrosine residues is involved in each of the modulatory changes. These results emphasize the complexity of signal integration at the level of a single ion channel.

scholarly journals Ondansetron blocks wild-type and p.F503L variant small-conductance Ca2+-activated K+ channels

2018 ◽  
Vol 315 (2) ◽  
pp. H375-H388 ◽  
Author(s):  
Jum-Suk Ko ◽  
Shuai Guo ◽  
Jonathan Hassel ◽  
Patricia Celestino-Soper ◽  
Ty C. Lynnes ◽  
...  
Keyword(s):  
Long Qt Syndrome ◽  
Qt Interval ◽  
Wild Type ◽  
Long Qt ◽  
Drug Induced ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells ◽  
Qt Syndrome ◽  
Small Conductance

Apamin-sensitive small-conductance Ca2+-activated K+ (SK) current ( IKAS) is encoded by Ca2+-activated K+ channel subfamily N ( KCNN) genes. IKAS importantly contributes to cardiac repolarization in conditions associated with reduced repolarization reserve. To test the hypothesis that IKAS inhibition contributes to drug-induced long QT syndrome (diLQTS), we screened for KCNN variants among patients with diLQTS, determined the properties of heterologously expressed wild-type (WT) and variant KCNN channels, and determined if the 5-HT3 receptor antagonist ondansetron blocks IKAS. We searched 2,306,335 records in the Indiana Network for Patient Care and found 11 patients with diLQTS who had DNA available in the Indiana Biobank. DNA sequencing discovered a heterozygous KCNN2 variant (p.F503L) in a 52-yr-old woman presenting with corrected QT interval prolongation at baseline (473 ms) and further corrected QT interval lengthening (601 ms) after oral administration of ondansetron. That patient was also heterozygous for the p.S38G and p.P2835S variants of the QT-controlling genes KCNE1 and ankyrin 2, respectively. Patch-clamp experiments revealed that the p.F503L KCNN2 variant heterologously expressed in human embryonic kidney (HEK)-293 cells augmented Ca2+ sensitivity, increasing IKAS density. The fraction of total F503L-KCNN2 protein retained in the membrane was higher than that of WT KCNN2 protein. Ondansetron at nanomolar concentrations inhibited WT and p.F503L SK2 channels expressed in HEK-293 cells as well as native SK channels in ventricular cardiomyocytes. Ondansetron-induced IKAS inhibition was also demonstrated in Langendorff-perfused murine hearts. In conclusion, the heterozygous p.F503L KCNN2 variant increases Ca2+ sensitivity and IKAS density in transfected HEK-293 cells. Ondansetron at therapeutic (i.e., nanomolar) concentrations is a potent IKAS blocker. NEW & NOTEWORTHY We showed that ondansetron, a 5-HT3 receptor antagonist, blocks small-conductance Ca2+-activated K+ (SK) current. Ondansetron may be useful in controlling arrhythmias in which increased SK current is a likely contributor. However, its SK-blocking effects may also facilitate the development of drug-induced long QT syndrome.

scholarly journals In Vitro Anti-cancer, Anti-hypertensive and Antihyperglycaemic effect of Hypoxis colchicifolia

2021 ◽  
Vol 21 (3) ◽  
pp. 209
Author(s):  
Suggessan Moodley ◽  
Depika Dwarka ◽  
Himansu Baijnath ◽  
John Jason Mellem
Keyword(s):  
Methanolic Extract ◽  
Therapeutic Potential ◽  
Herbal Medicines ◽  
A549 Cells ◽  
Positive Control ◽  
In Vivo Studies ◽  
Hek 293 ◽  
Anti Cancer

Economic challenges associated with non-communicable diseases and the sociocultural outlook of many patients especially in Africa has increased the dependence on traditional herbal medicines for these diseases. <em>Hypoxis colchicifolia</em> is a traditional medicinal plant used in Southern Africa against an array of ailments. This study evaluated the <em>in vitro</em> antidiabetic (α-amyalse and α-glucosidase), antihypertensive (angiotensin-converting enzyme) and anticancer potential of <em>H. colchicifolia</em> corm as well as leaf (acetone, methanol and aqueous) extracts. Results showed that extracts have a moderate anti-diabetic and anti-hypertensive potential, with great anti-cancer potential. The acetone extract of both fresh and dried corms produced significant α-amylase and α-glucosidase inhibition with ACE inhibited predominantly by the dried corms methanolic extract (IC<sub>50</sub> 368.2 μg/mL). Methanolic extract of dried leaves showed the least cytotoxicity against the noncancerous cell line HEK-293 while exhibiting the highest inhibition of MCF-7 cells (IC<sub>50</sub> 3.24 μg/mL). All extracts exhibited a greater inhibitory potential in A549 cells than the positive control camptothecin (IC<sub>50</sub> 304.2μg/mL). This study reveals that <em>H. colchicifolia</em> has therapeutic potential as an anti-diabetic and anticancer agent; however, further in vivo studies need to be conducted.

scholarly journals Species-Specific Regulation of TRPM2 by PI(4,5)P2 via the Membrane Interfacial Cavity

2021 ◽  
Vol 22 (9) ◽  
pp. 4637
Author(s):  
Daniel Barth ◽  
Andreas Lückhoff ◽  
Frank J. P. Kühn
Keyword(s):  
Amino Acid Residues ◽  
Hek 293 ◽  
Complete Inactivation ◽  
293 Cells ◽  
Activation Mechanisms ◽  
Specific Regulation ◽  
Species Specific ◽  
Inside Out ◽  
Positively Charged

The human apoptosis channel TRPM2 is stimulated by intracellular ADR-ribose and calcium. Recent studies show pronounced species-specific activation mechanisms. Our aim was to analyse the functional effect of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), commonly referred to as PIP2, on different TRPM2 orthologues. Moreover, we wished to identify the interaction site between TRPM2 and PIP2. We demonstrate a crucial role of PIP2, in the activation of TRPM2 orthologues of man, zebrafish, and sea anemone. Utilizing inside-out patch clamp recordings of HEK-293 cells transfected with TRPM2, differential effects of PIP2 that were dependent on the species variant became apparent. While depletion of PIP2 via polylysine uniformly caused complete inactivation of TRPM2, restoration of channel activity by artificial PIP2 differed widely. Human TRPM2 was the least sensitive species variant, making it the most susceptible one for regulation by changes in intramembranous PIP2 content. Furthermore, mutations of highly conserved positively charged amino acid residues in the membrane interfacial cavity reduced the PIP2 sensitivity in all three TRPM2 orthologues to varying degrees. We conclude that the membrane interfacial cavity acts as a uniform PIP2 binding site of TRPM2, facilitating channel activation in the presence of ADPR and Ca2+ in a species-specific manner.

scholarly journals Preliminary Study on Pasta Samples Characterized in Antioxidant Compounds and Their Biological Activity on Kidney Cells

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1131 ◽  
Author(s):  
Federico Di Marco ◽  
Francesco Trevisani ◽  
Pamela Vignolini ◽  
Silvia Urciuoli ◽  
Andrea Salonia ◽  
...  
Keyword(s):  
Indoleacetic Acid ◽  
Antioxidant Properties ◽  
Antioxidant Compounds ◽  
Kidney Cells ◽  
Hek 293 ◽  
293 Cells ◽  
High Concentrations ◽  
Β Carotene ◽  
Egg Pasta

Pasta is one of the basic foods of the Mediterranean diet and for this reason it was chosen for this study to evaluate its antioxidant properties. Three types of pasta were selected: buckwheat, rye and egg pasta. Qualitative–quantitative characterization analyses were carried out by HPLC-DAD to identify antioxidant compounds. The data showed the presence of carotenoids such as lutein and polyphenols such as indoleacetic acid, (carotenoids from 0.08 to 0.16 mg/100 g, polyphenols from 3.7 to 7.4 mg/100 g). To assess the effect of the detected metabolites, in vitro experimentation was carried out on kidney cells models: HEK-293 and MDCK. Standards of β-carotene, indoleacetic acid and caffeic acid, hydroalcoholic and carotenoid-enriched extracts from samples of pasta were tested in presence of antioxidant agent to determine viability variations. β-carotene and indoleacetic acid standards exerted a protective effect on HEK-293 cells while no effect was detected on MDCK. The concentrations tested are likely in the range of those reached in body after the consumption of a standard pasta meal. Carotenoid-enriched extracts and hydroalcoholic extracts showed different effects, observing rescues for rye pasta hydroalcoholic extract and buckwheat pasta carotenoid-enriched extract, while egg pasta showed milder dose depending effects assuming pro-oxidant behavior at high concentrations. The preliminary results suggest behaviors to be traced back to the whole phytocomplexes respect to single molecules and need further investigations.

scholarly journals Electron Paramagnetic Resonance Gives Evidence for the Presence of Type 1 Gonadotropin-Releasing Hormone Receptor (GnRH-R) in Subdomains of Lipid Rafts

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 973
Author(s):  
Tilen Koklič ◽  
Alenka Hrovat ◽  
Ramon Guixà-González ◽  
Ismael Rodríguez-Espigares ◽  
Damaris Navio ◽  
...  
Keyword(s):  
Lipid Rafts ◽  
Order Parameter ◽  
Spin Probe ◽  
Gonadotropin Releasing Hormone ◽  
Paramagnetic Resonance ◽  
Hek 293 ◽  
293 Cells ◽  
Gonadotropin Releasing Hormone Receptor ◽  
Electron Paramagnetic

This study investigated the effect of type 1 gonadotropin releasing hormone receptor (GnRH-R) localization within lipid rafts on the properties of plasma membrane (PM) nanodomain structure. Confocal microscopy revealed colocalization of PM-localized GnRH-R with GM1-enriched raft-like PM subdomains. Electron paramagnetic resonance spectroscopy (EPR) of a membrane-partitioned spin probe was then used to study PM fluidity of immortalized pituitary gonadotrope cell line αT3-1 and HEK-293 cells stably expressing GnRH-R and compared it with their corresponding controls (αT4 and HEK-293 cells). Computer-assisted interpretation of EPR spectra revealed three modes of spin probe movement reflecting the properties of three types of PM nanodomains. Domains with an intermediate order parameter (domain 2) were the most affected by the presence of the GnRH-Rs, which increased PM ordering (order parameter (S)) and rotational mobility of PM lipids (decreased rotational correlation time (τc)). Depletion of cholesterol by methyl-β-cyclodextrin (methyl-β-CD) inhibited agonist-induced GnRH-R internalization and intracellular Ca2+ activity and resulted in an overall reduction in PM order; an observation further supported by molecular dynamics (MD) simulations of model membrane systems. This study provides evidence that GnRH-R PM localization may be related to a subdomain of lipid rafts that has lower PM ordering, suggesting lateral heterogeneity within lipid raft domains.

scholarly journals Characteristics and requirements of basal autophagy in HEK 293 cells

Autophagy ◽  
2013 ◽  
Vol 9 (9) ◽  
pp. 1407-1417 ◽  
Author(s):  
Patience Musiwaro ◽  
Matthew Smith ◽  
Maria Manifava ◽  
Simon A. Walker ◽  
Nicholas T. Ktistakis
Keyword(s):  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells

scholarly journals Using kICS to Reveal Changed Membrane Diffusion of AQP-9 Treated with Drugs

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 568
Author(s):  
Jakob L. Kure ◽  
Thommie Karlsson ◽  
Camilla B. Andersen ◽  
B. Christoffer Lagerholm ◽  
Vesa Loitto ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Plasma Membrane ◽  
Membrane Proteins ◽  
Actin Polymerization ◽  
Correlation Spectroscopy ◽  
Image Correlation ◽  
Membrane Diffusion ◽  
Hek 293 ◽  
293 Cells ◽  
Aquaporin 9

The formation of nanodomains in the plasma membrane are thought to be part of membrane proteins regulation and signaling. Plasma membrane proteins are often investigated by analyzing the lateral mobility. k-space ICS (kICS) is a powerful image correlation spectroscopy (ICS) technique and a valuable supplement to fluorescence correlation spectroscopy (FCS). Here, we study the diffusion of aquaporin-9 (AQP9) in the plasma membrane, and the effect of different membrane and cytoskeleton affecting drugs, and therefore nanodomain perturbing, using kICS. We measured the diffusion coefficient of AQP9 after addition of these drugs using live cell Total Internal Reflection Fluorescence imaging on HEK-293 cells. The actin polymerization inhibitors Cytochalasin D and Latrunculin A do not affect the diffusion coefficient of AQP9. Methyl-β-Cyclodextrin decreases GFP-AQP9 diffusion coefficient in the plasma membrane. Human epidermal growth factor led to an increase in the diffusion coefficient of AQP9. These findings led to the conclusion that kICS can be used to measure diffusion AQP9, and suggests that the AQP9 is not part of nanodomains.

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