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Ability to induce atrial fibrillation in the peri-operative period is associated with phosphorylation-dependent inhibition of TWIK protein-related acid-sensitive potassium channel 1 (TASK-1).

ABSTRACT: Peri-operative atrial fibrillation (peri-op AF) is a common complication following thoracic surgery. This arrhythmia is thought to be triggered by an inflammatory response and can be reproduced in various animal models. Previous work has shown that the lipid inflammatory mediator, platelet-activating factor (PAF), synthesized by activated neutrophils, can induce atrial and ventricular arrhythmias as well as repolarization abnormalities in isolated ventricular myocytes. We have previously shown that carbamylated PAF-induced repolarization abnormalities result from the protein kinase C (PKC) ε-dependent phosphorylation of the two-pore domain potassium channel TASK-1. We now demonstrate that canine peri-op AF is associated with the phosphorylation-dependent loss of TASK-1 current. Further studies identified threonine 383 in the C terminus of human and canine TASK-1 as the phosphorylation site required for PAF-dependent inhibition of the channel. Using a novel phosphorylation site-specific antibody targeting the phosphorylated channel, we have determined that peri-op AF is associated with the loss of TASK-1 current and increased phosphorylation of TASK-1 at this site.

SUBMITTER: Harleton E

PROVIDER: S-EPMC3554947 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature

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Ability to induce atrial fibrillation in the peri-operative period is associated with phosphorylation-dependent inhibition of TWIK protein-related acid-sensitive potassium channel 1 (TASK-1).

Harleton Erin E Besana Alessandra A Comas George M GM Danilo Peter P Rosen Tove S TS Argenziano Michael M Rosen Michael R MR Robinson Richard B RB Feinmark Steven J SJ

The Journal of biological chemistry 20121210 4

Peri-operative atrial fibrillation (peri-op AF) is a common complication following thoracic surgery. This arrhythmia is thought to be triggered by an inflammatory response and can be reproduced in various animal models. Previous work has shown that the lipid inflammatory mediator, platelet-activating factor (PAF), synthesized by activated neutrophils, can induce atrial and ventricular arrhythmias as well as repolarization abnormalities in isolated ventricular myocytes. We have previously shown t ...[more]

PMID: 23229553

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Project description:Background: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and one of the major causes of cardiovascular morbidity and mortality. Despite good progress within the past years, safe and effective treatment of AF remains an unmet clinical need. The anti-anginal agent ranolazine has been shown to exhibit antiarrhythmic properties via mainly late INa and IKr blockade. This results in prolongation of the atrial action potential duration (APD) and effective refractory period (ERP) with lower effect on ventricular electrophysiology. Furthermore, ranolazine has been shown to be effective in the treatment of AF. TASK-1 is a two-pore domain potassium (K2P) channel that shows nearly atrial specific expression within the human heart and has been found to be upregulated in AF, resulting in shortening the atrial APD in patients suffering from AF. We hypothesized that inhibition TASK-1 contributes to the observed electrophysiological and clinical effects of ranolazine. Methods: We used Xenopus laevis oocytes and CHO-cells as heterologous expression systems for the study of TASK-1 inhibition by ranolazine and molecular drug docking simulations to investigate the ranolazine binding site and binding characteristics. Results: Ranolazine acts as an inhibitor of TASK-1 potassium channels that inhibits TASK-1 currents with an IC50 of 30.6 ± 3.7 µM in mammalian cells and 198.4 ± 1.1 µM in X. laevis oocytes. TASK-1 inhibition by ranolazine is not frequency dependent but shows voltage dependency with a higher inhibitory potency at more depolarized membrane potentials. Ranolazine binds within the central cavity of the TASK-1 inner pore, at the bottom of the selectivity filter. Conclusions: In this study, we show that ranolazine inhibits TASK-1 channels. We suggest that inhibition of TASK-1 may contribute to the observed antiarrhythmic effects of Ranolazine. This puts forward ranolazine as a prototype drug for the treatment of atrial arrhythmia because of its combined efficacy on atrial electrophysiology and lower risk for ventricular side effects.

Project description:BackgroundBranched-chain amino acids (BCAAs; leucine, isoleucine, and valine) are essential amino acids involved in immune responses, and may have roles in protein malnutrition and sarcopenia. Furthermore, certain liver diseases have been associated with a decreased Fischer's ratio (BCAAs to aromatic amino acids; phenylalanine, tyrosine, and tryptophan). We aimed to evaluate the safety and efficacy of BCAAs use in patients with cancer undergoing surgery.MethodsMEDLINE, Embase, and CENTRAL were searched (inception to July 24, 2020) for randomized controlled trials (RCTs) and comparative observational studies in English evaluating BCAAs (alone or in combinations) during the oncological peri-operative period. Study selection, data extraction, and quality appraisal were done in duplicate. RCT risk-of-bias was appraised using Cochrane Risk-of-Bias tool, and observational studies' quality assessment was conducted with Newcastle-Ottawa Scale. Meta-analyses were conducted when appropriate.Results20 articles were included comprising 13 RCTs and 6 observational cohort studies in 7 reports and 2019 total participants overall. Among 13 RCTs, 77% involved liver cancer. Methodological study quality scored substantial risk-of-bias across most RCTs. Meta-analysis of RCTs found a 38% decreased risk of post-operative infections in BCAAs group compared to controls (RR = 0.62; 95% CI = 0.44 to 0.87; P = .006; number of RCTs, k = 6; total sample size, N = 389; I2 = 0%). BCAAs were also found to be beneficial for ascites (RR = 0.55; 95% CI = 0.35 to 0.86; P = .008; k = 4; N = 296; I2 = 0%), body weight (MD = 3.24 kg; 95% CI = 0.44 to 6.04; P = .02; k = 3; N = 196; I2 = 24%), and hospitalization length (MD = -2.07 days; 95% CI = -3.97 to -0.17; P = .03; k = 5; N = 362; I2 = 59%). No differences were found between BCAAs and controls for mortality, recurrence, other post-operative complications (liver failure, edema, pleural effusion), blood loss, quality of life, ammonia level, and prothrombin time. No serious adverse events were related to BCAAs; however, serious adverse events were reported due to intravenous catheters. No safety concerns from observational studies were identified.ConclusionsBranched-chain amino acids during the oncological surgical period demonstrated promise in reducing important post-operative morbidity from infections and ascites compared to controls. Blinded, placebo-controlled confirmatory trials of higher methodological quality are warranted, especially using oral, short-term BCAAs-enriched supplements within the context of recent ERAS programs.Prospero registrationCRD42018086168.

Dataset Information

Ability to induce atrial fibrillation in the peri-operative period is associated with phosphorylation-dependent inhibition of TWIK protein-related acid-sensitive potassium channel 1 (TASK-1).

Publications

Ability to induce atrial fibrillation in the peri-operative period is associated with phosphorylation-dependent inhibition of TWIK protein-related acid-sensitive potassium channel 1 (TASK-1).

Similar Datasets

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