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Evidence-based Complementary and... 2023[This retracts the article DOI: 10.1155/2022/7619998.].
[This retracts the article DOI: 10.1155/2022/7619998.].
PubMed: 37829641
DOI: 10.1155/2023/9841358 -
Journal of Thoracic Disease Aug 2023Long QT syndrome type 2 (LQT2) is caused by mutations in the /human ether-à-go-go-related gene (hERG). Some hERG genetic mutation-associated diseases are alleviated by...
4-phenylbutyric acid re-trafficking hERG/G572R channel protein by modulating the endoplasmic reticulum stress-associated chaperones and endoplasmic reticulum-associated degradation gene.
BACKGROUND
Long QT syndrome type 2 (LQT2) is caused by mutations in the /human ether-à-go-go-related gene (hERG). Some hERG genetic mutation-associated diseases are alleviated by hERG-specific drug chaperones (glycerol, dimethyl sulfoxide, trimethylamine N-oxide, thapsigargin), delayed rectifier K current (IKr) blockers methanesulfonanilide E4031, the antihistamine astemizole, or the prokinetic drug cisapride, and the anti-arrhythmic drug quinidine. Meanwhile, many and studies have reported the efficacy of 4-phenylbutyric acid (4-PBA) in diseases with inherited genetic mutations. This study aims to explore potential therapeutic agents for hERG/G572R mutated ion channel.
METHODS
pcDNA3/hERG [wild type (WT)]-FLAG and pcDNA3/hERG (G572R)-FLAG plasmids were transfected into HEK293 cells. A western blot (WB) experiment was conducted to analyze protein expression. Quantitative real-time polymerase chain reaction (qPCR) was used to analyze the messenger RNA (mRNA) expression levels in the WT/G572R heterozygous HEK293 cell model treated with or without 4-PBA. The interaction between WT/G572R and BIP (GRP78), GRP94, and 3-hydroxy-3-methylglutaryl coenzyme A reductase degradation protein 1 (HRD1) was tested by co-immunoprecipitation (co-IP). To investigate the effect of 4-PBA on the WT/G572R channel current, we used electrophysiological assays (patch-clamp electrophysiological recordings).
RESULTS
The results showed that WT/G572R activated the ATF6 pathway in the endoplasmic reticulum stress (ERS), the ERS response markers GRP78, GRP94, and calreticulin (CRT)/calnexin (CNX), and HRD1, which decreased after application of the ERS inhibitor 4-PBA. The results of co-IP confirmed that the ability of hERG interacted with GRP78, GRP94, and HRD1. Moreover, 4-PBA increased the current of WT/G572R and reversed the gating kinetics of the WT/G572R channel.
CONCLUSIONS
4-PBA corrects hERG channel transport defects by inhibiting excessive ERS and the endoplasmic reticulum-associated degradation (ERAD)-related gene E3 ubiquitin ligase HRD1. Additionally, 4-PBA improved WT/G572R channel current. 4-PBA is expected to be developed as a new treatment method for LQT2.
PubMed: 37691654
DOI: 10.21037/jtd-23-1252 -
International Journal of Molecular... Aug 2023loss-of-function mutations cause long QT syndrome type 2 (LQT2), an inherited cardiac disorder associated with life-threatening ventricular arrhythmia. Through...
loss-of-function mutations cause long QT syndrome type 2 (LQT2), an inherited cardiac disorder associated with life-threatening ventricular arrhythmia. Through whole-exome sequencing, we discovered a novel AGCGACAC deletion (S981fs) in the gene of an LQT2 patient. Using a heterologous expression system and patch clamping, we found that the mutant K channel had reduced cell surface expression and lower current amplitude compared to the wild type. However, functional expression was restored by lowering temperature and using potassium channel inhibitors or openers (E4031, cisapride, nicorandil). Co-immunoprecipitation experiments confirmed the assembly of mutant proteins with wild-type hERG. Confocal imaging showed decreased hERG distribution on the cell membrane in cells expressing S981fs. Notably, treatment with G418 significantly increased hERG current in wild-type/S981fs heterozygotes. In conclusion, our study identifies a novel mutation leading to impaired Kv11.1 function due to trafficking and nonsense-mediated RNA decay defects. These findings shed light on the mechanisms underlying LQT2 and offer potential therapeutic avenues.
Topics: Humans; Exome Sequencing; Long QT Syndrome; Heart; Cell Membrane; Mutation; ERG1 Potassium Channel
PubMed: 37628921
DOI: 10.3390/ijms241612742 -
Molecules (Basel, Switzerland) Jul 2023Erythromycin is one of the few compounds that remarkably increase ether-a-go-go-related gene (hERG) inhibition from room temperature (RT) to physiological temperature...
Erythromycin is one of the few compounds that remarkably increase ether-a-go-go-related gene (hERG) inhibition from room temperature (RT) to physiological temperature (PT). Understanding how erythromycin inhibits the hERG could help us to decide which compounds are needed for further studies. The whole-cell patch clamp technique was used to investigate the effects of erythromycin on hERG channels at different temperatures. While erythromycin caused a concentration-dependent inhibition of cardiac hERG channels, it also shifted the steady-state activation and steady-state inactivation of the channel to the left and significantly accelerated the onset of inactivation at both temperatures, although temperature itself caused a profound change in the dynamics of hERG channels. Our data also suggest that the binding pattern to S6 of the channels changes at PT. In contrast, cisapride, a well-known hERG blocker whose inhibition is not affected by temperature, does not change its critical binding sites after the temperature is raised to PT. Our data suggest that erythromycin is unique and that the shift in hERG inhibition may not apply to other compounds.
Topics: Ether-A-Go-Go Potassium Channels; Erythromycin; Temperature; Cisapride; Heart; ERG1 Potassium Channel; Potassium Channel Blockers
PubMed: 37446837
DOI: 10.3390/molecules28135176 -
JFMS Open Reports 2023Two 6-month-old littermate Russian Blue cross kittens presented for megaesophagus, intermittent vomiting and regurgitation. The male kitten was diagnosed with aspiration...
CASE SUMMARY
Two 6-month-old littermate Russian Blue cross kittens presented for megaesophagus, intermittent vomiting and regurgitation. The male kitten was diagnosed with aspiration pneumonia and was suspected to have a hiatal hernia on thoracic radiographs. It presented 1 month later in acute respiratory distress and was euthanized. Post-mortem examination revealed a severe gastroesophageal intussusception with approximately 90% of the stomach inverted into the distal esophagus. Histologic examination confirmed dysautonomia with marked neuronal dropout and degeneration with necrosis, satellitosis of the celiac ganglion and the myenteric and submucosal plexuses throughout the gastrointestinal tract. The less-affected littermate showed improvement on cisapride and was doing well at home at the time of writing.
RELEVANCE AND NOVEL INFORMATION
Dysautonomia is rare in cats, with only a few reports of affected littermates. Both kittens are significantly younger than the median age previously reported. Detailed descriptions of diagnostic and histopathology findings are included. Gastroesophageal intussusception is a novel complication to consider when managing feline dysautonomia.
PubMed: 37151741
DOI: 10.1177/20551169231164579 -
Nutrients Apr 2023The fruit of L. (MAF) has been consumed as a food worldwide. MAF has also been widely used in traditional medicine for thousands of years in East Asia, and its diverse...
The fruit of L. (MAF) has been consumed as a food worldwide. MAF has also been widely used in traditional medicine for thousands of years in East Asia, and its diverse bioactivities have been reported in numerous publications. However, no prokinetic activity has been reported for MAF or its components. In the present study, therefore, we investigated the effects of MAF on gastrointestinal motor function by measuring the intestinal transit rate (ITR) of Evans blue in mice in vivo. The ITR values accelerated by MAF were significantly higher than those accelerated by cisapride or metoclopramide, suggesting that MAF has potential as a new prokinetic agent to replace cisapride and metoclopramide. We also investigated the effects of MAF on myogenic and neurogenic contractions in human intestinal smooth muscles by measuring spontaneous contractions of smooth muscle strips, smooth muscle contractions induced by neural stimulation, and migrating motor complexes from intestinal segments in the human ileum and sigmoid colon in situ. MAF increased both myogenic and neurogenic contractions to enhance ileal and colonic motility in the human intestine. Taken together, these results indicate that MAF enhanced intestinal motility by increasing both myogenic and neurogenic contractions, thereby accelerating the ITR.
Topics: Humans; Mice; Animals; Cisapride; Morus; Metoclopramide; Fruit; Gastrointestinal Motility
PubMed: 37111108
DOI: 10.3390/nu15081889 -
United European Gastroenterology Journal Mar 2023Gastroparesis and functional dyspepsia are disorders characterized by upper gastrointestinal symptoms and multifaceted etiologies. One of the main therapeutic approaches... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Gastroparesis and functional dyspepsia are disorders characterized by upper gastrointestinal symptoms and multifaceted etiologies. One of the main therapeutic approaches is accelerating gastric emptying (GE) by means of prokinetic agents. Their efficacy has been demonstrated, although the association between symptom improvement and acceleration of emptying is less clear. Meta-analyses have found contradictory results. Differences in applied methodology and included trials might drive these contradictions.
OBJECTIVE
To provide a transparent meta-analysis update to elucidate the association between symptom improvement and acceleration of GE due to gastroprokinetic agents available for long-term use in patients with gastroparesis.
DESIGN
Two approaches from earlier meta-analyses were executed and compared. One analyzed the relative changes on active treatment versus baseline, the other compared the change from baseline on active treatment versus the change from baseline on placebo. Papers that reported sufficient numerical data for both analyses were selected. Both analyses included the same trials.
RESULTS
Overall, both approaches yield the same positive direction of association between symptom improvement and acceleration of emptying (0.291 (-0.391, 0.972), p = 0.4 and 0.453 (0.123, 0.782), p = 0.007 for the active-only and placebo-controlled analysis respectively). The association between symptom improvement and GE acceleration for studies using optimal GE tests was either 0.028 (p > 0.9) or 0.463 (p = 0.007), and for sub-optimal GE tests was either 0.370 (p = 0.4) or 0.052 (p > 0.9) depending on the used meta-analysis methodology.
CONCLUSIONS
The applied methodology for GE testing, and the meta-analysis substantially impacts the conclusion. When considering the clinically relevant outcome of improvement from baseline, symptoms and emptying improve with prokinetics, but no correlation is found between both aspects. When the change over placebo is considered, limiting the analysis to scientifically more rigorous study approaches, changes in emptying rate and symptom improvement are positively associated.
Topics: Humans; Gastric Emptying; Gastroparesis; Gastrointestinal Agents; Cisapride; Dyspepsia
PubMed: 36714973
DOI: 10.1002/ueg2.12362 -
Children (Basel, Switzerland) Nov 2022QTc interval measurement is a widely used screening tool to assess the risk of cardiac diseases, arrhythmias, and is a useful biomarker for pharmacovigilance. However,... (Review)
Review
QTc interval measurement is a widely used screening tool to assess the risk of cardiac diseases, arrhythmias, and is a useful biomarker for pharmacovigilance. However, the interpretation of QTc is difficult in neonates due to hemodynamic maturational changes and uncertainties on reference values. To describe trends in QTc values throughout infancy (1 year of life), and to explore the impact of (non)-maturational changes and medicines exposure, a structured systematic review (PROSPERO CRD42022302296) was performed. In term neonates, a decrease was observed over the first week of life, whereafter values increased until two months of age, followed by a progressive decrease until six months. A similar pattern with longer QTc values was observed in preterms. QTc is influenced by cord clamping, hemodynamic changes, therapeutic hypothermia, illnesses and sleep, not by sex. Cisapride, domperidone and doxapram result in QTc prolongation in neonates. Further research in this age category is needed to improve primary screening practices and QTcthresholds, earlier detection of risk factors and precision pharmacovigilance.
PubMed: 36421220
DOI: 10.3390/children9111771 -
Journal of Pharmacological and... 2022ICH S7B recommends screening for hERG channel block using patch clamp recordings to assess a drug's proarrhythmic risk. Block of the hERG channel has been associated...
ICH S7B recommends screening for hERG channel block using patch clamp recordings to assess a drug's proarrhythmic risk. Block of the hERG channel has been associated with clinical QT prolongation as well as the rare, but potentially fatal ventricular tachyarrhythmia Torsade de Pointes (TdP). During recording, drug concentrations perfused to the cells can deviate from nominal concentrations due to molecule-specific properties (such as non-specific binding), thereby introducing error when assessing drug potency. To account for this potential source of error, both the original ICH S7B and the newly released ICH E14/S7B Q&As guidelines call for verifying drug solutions' concentrations. Dofetilide, cisapride, terfenadine, sotalol and E-4031 are hERG blockers commonly used as positive controls to illustrate hERG assay sensitivity. The first four compounds are also clinical drugs associated with high TdP risk; therefore, their safety margins may be useful comparators to better understand an investigational product's TdP risk. Having analytical methods to quantify these five compounds in the hERG external solution that will be used for patch clamp recordings is important from a regulatory science research perspective. However, a literature search revealed no analytical methods or stability information for these molecules in the high salt, serum-free matrix that constitutes the hERG external solution. This study was conducted to develop and validate LC-MS/MS methods to quantify these 5 molecules in hERG external solution. The bioanalytical methods for these positive controls were validated as per the FDA's bioanalytical method validation guidance along with various stabilities.
Topics: Humans; Chromatography, Liquid; Tandem Mass Spectrometry; Torsades de Pointes; Long QT Syndrome; DNA-Binding Proteins; Ether-A-Go-Go Potassium Channels
PubMed: 36334898
DOI: 10.1016/j.vascn.2022.107229 -
Frontiers in Endocrinology 2022Mutations in has been proved to cause hypoinsulinemia and diabetes in human and mice. Cisapride is a stomach-intestinal motility drug used to treat gastrointestinal...
Mutations in has been proved to cause hypoinsulinemia and diabetes in human and mice. Cisapride is a stomach-intestinal motility drug used to treat gastrointestinal dysfunction. Cisapride has been reported to be a potential inhibitor of the KCNH family, but it remained unclear whether cisapride inhibited KCNH6. Here, we discovered the role of cisapride on glucose metabolism, focusing on the KCNH6 potassium channel protein. Cisapride reduced blood glucose level and increased serum insulin secretion in wild-type (WT) mice fed standard normal chow/a high-fat diet or in db/db mice, especially when combined with tolbutamide. This effect was much stronger after 4 weeks of intraperitoneal injection. Whole-cell patch-clamp showed that cisapride inhibited KCNH6 currents in transfected HEK293 cells in a concentration-dependent manner. Cisapride induced an increased insulin secretion through the disruption of intracellular calcium homeostasis in a rat pancreatic β-cell line, INS-1E. Further experiments revealed that cisapride did not decrease blood glucose or increase serum insulin in KCNH6 β-cell knockout (Kcnh6-β-KO) mice when compared with WT mice. Cisapride also ameliorated glucose-stimulated insulin secretion (GSIS) in response to high glucose in WT but not Kcnh6-β-KO mice. Thus, our data reveal a novel way for the effect of KCNH6 in cisapride-induced hypoglycemia.
Topics: Humans; Rats; Mice; Animals; Blood Glucose; Cisapride; Insulin; Potassium Channels; HEK293 Cells; Hypoglycemia; Glucose; Ether-A-Go-Go Potassium Channels
PubMed: 36325440
DOI: 10.3389/fendo.2022.1011238