LUF7244 plus Dofetilide Rescues Aberrant Kv11.1 Trafficking and Produces Functional IKv11.1

Kv11.1 (hERG) channels play a critical role in repolarization of cardiomyocytes during the cardiac action potential (AP). Drug mediated Kv11.1 blockade results in AP prolongation, which poses an increased risk of sudden cardiac death. Many drugs, like pentamidine, interfere with normal Kv11.1 forward trafficking and thus reduce functional Kv11.1 channel densities. Although class III antiarrhythmics, e.g. dofetilide, rescue congenital and acquired forward trafficking defects, this is of little use due to their simultaneous acute channel blocking effect. We aimed to test the ability of a combination of dofetilide plus LUF7244, a Kv11.1 allosteric modulator/activator, to rescue Kv11.1 trafficking and produce functional Kv11.1 current. LUF7244 treatment by itself did not disturb or rescue WT or G601S Kv11.1 trafficking as shown by western blot and immunofluorescence microcopy analysis. Pentamidine-decreased maturation of WT Kv11.1 levels was rescued by 10 μM dofetilide or 10 μM dofetilide + 5 μM LUF7244. In trafficking defective G601S Kv11.1 cells, dofetilide (10 μM) or dofetilide+LUF7244 (10+5 μM) restored Kv11.1 trafficking also, as demonstrated by western blot and immunofluorescence microscopy. LUF7244 (10 μM) increased IKv11.1 despite the presence of dofetilide (1 μM) in WT Kv11.1 cells. In G601S expressing cells, long-term treatment (24-48 h) with LUF7244 (10 μM) and dofetilide (1 μM) increased IKv11.1 compared to non-treated, or acutely treated cells. We conclude that dofetilide plus LUF7244 rescues Kv11.1 trafficking and produces functional IKv11.1. Thus, combined administration of LUF7244 and an IKV11.1 trafficking corrector could serve as a new pharmacological therapy of both congenital and drug-induced Kv11.1 trafficking defects.Toxicolog

Stedelijk goederenvervoer nu en in de toekomst

OTB Research Institute for the Built Environmen

Intratumoral HPV16-Specific T Cells Constitute a Type I-Oriented Tumor Microenvironment to Improve Survival in HPV16-Driven Oropharyngeal Cancer

Transplantation and autoimmunit

LUF7244, an allosteric modulator/activator of K v

Background and PurposeKv11.1 (hERG) channel blockade is an adverse effect of many drugs and lead compounds, associated with lethal cardiac arrhythmias. LUF7244 is a negative allosteric modulator/activator of Kv11.1 channels that inhibits early afterdepolarizations in vitro. We tested LUF7244 for antiarrhythmic efficacy and potential proarrhythmia in a dog model.Experimental ApproachLUF7244 was tested in vitro for (a) increasing human IKv11.1 and canine IKr and (b) decreasing dofetilide‐induced action potential lengthening and early afterdepolarizations in cardiomyocytes derived from human induced pluripotent stem cells and canine isolated ventricular cardiomyocytes. In vivo, LUF7244 was given intravenously to anaesthetized dogs in sinus rhythm or with chronic atrioventricular block.Key ResultsLUF7244 (0.5–10 μM) concentration dependently increased IKv11.1 by inhibiting inactivation. In vitro, LUF7244 (10 μM) had no effects on IKIR2.1, INav1.5, ICa‐L, and IKs, doubled IKr, shortened human and canine action potential duration by approximately 50%, and inhibited dofetilide‐induced early afterdepolarizations. LUF7244 (2.5 mg·kg−1·15 min−1) in dogs with sinus rhythm was not proarrhythmic and shortened, non‐significantly, repolarization parameters (QTc: −6.8%). In dogs with chronic atrioventricular block, LUF7244 prevented dofetilide‐induced torsades de pointes arrhythmias in 5/7 animals without normalization of the QTc. Peak LUF7244 plasma levels were 1.75 ± 0.80 during sinus rhythm and 2.34 ± 1.57 μM after chronic atrioventricular block.Conclusions and ImplicationsLUF7244 counteracted dofetilide‐induced early afterdepolarizations in vitro and torsades de pointes in vivo. Allosteric modulators/activators of Kv11.1 channels might neutralize adverse cardiac effects of existing drugs and newly developed compounds that display QTc lengthening.Pharmacolog

LUF7244, an allosteric modulator/activator of Kv11.1 channels, counteracts dofetilide‐induced torsades de pointes arrhythmia in the chronic atrioventricular block dog model

Background and PurposeKv11.1 (hERG) channel blockade is an adverse effect of many drugs and lead compounds, associated with lethal cardiac arrhythmias. LUF7244 is a negative allosteric modulator/activator of Kv11.1 channels that inhibits early afterdepolarizations in vitro. We tested LUF7244 for antiarrhythmic efficacy and potential proarrhythmia in a dog model.Experimental ApproachLUF7244 was tested in vitro for (a) increasing human IKv11.1 and canine IKr and (b) decreasing dofetilide‐induced action potential lengthening and early afterdepolarizations in cardiomyocytes derived from human induced pluripotent stem cells and canine isolated ventricular cardiomyocytes. In vivo, LUF7244 was given intravenously to anaesthetized dogs in sinus rhythm or with chronic atrioventricular block.Key ResultsLUF7244 (0.5–10 μM) concentration dependently increased IKv11.1 by inhibiting inactivation. In vitro, LUF7244 (10 μM) had no effects on IKIR2.1, INav1.5, ICa‐L, and IKs, doubled IKr, shortened human and canine action potential duration by approximately 50%, and inhibited dofetilide‐induced early afterdepolarizations. LUF7244 (2.5 mg·kg−1·15 min−1) in dogs with sinus rhythm was not proarrhythmic and shortened, non‐significantly, repolarization parameters (QTc: −6.8%). In dogs with chronic atrioventricular block, LUF7244 prevented dofetilide‐induced torsades de pointes arrhythmias in 5/7 animals without normalization of the QTc. Peak LUF7244 plasma levels were 1.75 ± 0.80 during sinus rhythm and 2.34 ± 1.57 μM after chronic atrioventricular block.Conclusions and ImplicationsLUF7244 counteracted dofetilide‐induced early afterdepolarizations in vitro and torsades de pointes in vivo. Allosteric modulators/activators of Kv11.1 channels might neutralize adverse cardiac effects of existing drugs and newly developed compounds that display QTc lengthening.Pharmacolog

Archeologische Kroniek 2005: Holland, Historisch Tijdschrift

In de Archeologische Kroniek wordt een overzicht gegeven van archeologische vondsten in Noord- en Zuid-Holland, per plaats. Dit wordt weergegeven in alfabetische volgorde per provincie