Y gain-of-function mutations in the KCND3encoded Kv4.3 channels is the

Y gain-of-function mutations in the KCND3encoded Kv4.3 channels is the molecular pathogenesis for the lethal arrhythmia in patients with Brugada syndrome [30]. Suppression of ventricular arrhythmia in Brugada patients with quinidine [32,33] is believed to be related to its Ito blocking effect [34?6]. A recent study has reported that oxidation stress increases Ito conductance and promotes EADs (early after-depolarizations) by setting myocardial action potential plateau into the voltage range where ICa,L reactivation is facilitated and IKs activation is slowed, and the EADs are suppressed by the Ito blocker 4-AP [28]. It should be noted that Ito inhibition by 4-AP may restore the epicardial action potential dome, reduce both transmural and epicardial dispersion of repolarization, normalize the ST segment, and prevent phase 2 reentry and ventricular tachycardia/ ventricular fibrillation in experimental Brugada syndrome[15,31,37]. These studies suggest that Ito blockade also has a therapeutic effect on ventricular arrhythmias resulted from oxidation-induced EADs or Brugada syndrome. Acacetin has a strong inhibition of hKv4.3 current, and may also be a candidate drug in suppressing ventricular arrhythmias related to Brugada syndrome. Although acacetin also blocks hKv1.5 channels, this effect would not affect other phases of action potential in human ventricles, because no functional hKv1.5/IKur is present in ventricular myocytes of human hearts [38]. Blockade of hKv4.3 by acacetin would favor the correction of Brugada’s abnormal Epigenetics repolarization at early phase (phase 1) action potential in human ventricles; however, this remains further investigation in the future. Collectively, the present study demonstrates that acacetin mainly blocks hKv4.3 channels by binding to open states and interacting with T366 and T367 in the P-loop helix and V392, I395, and V399 within the S6 domain. The use- and frequencydependent blocking property of the hKv4.3 channels and also hKv1.5 channels suggest that this Autophagy natural flavone compound could strongly inhibit atrial fibrillation. Further effort is required to study whether it is effective in managing ventricular arrhythmias related to Brugada Syndrome.Supporting InformationFigure S1 Effect of acacetin on closed-state inactivation of hKv4.3 channels. (PDF)Author ContributionsConceived and designed the experiments: GRL. Performed the experiments: HJW HYS WW YHZ. Analyzed the data: HJW HYS. Contributed reagents/materials/analysis tools: GWQ. Wrote the paper: HJW GRL.
Periodontitis comprises a group of multifactorial inflammatory diseases that affect the periodontium, i.e. the epithelial, connective and bone tissues that both surround and support the teeth [1]. From a pathophysiological point of view, inflammatory host mediators are involved in the detachment of the gingival connective tissue from the root surface, and in the resorption of alveolar bone supporting the tooth. The natural history of the disease leads to tooth loss. Chronic periodontitis is one of the most prevalent low-grade, bacterially induced, chronic inflammatory diseases affecting 20 to 50 of the adult population worldwide [2,3]. The low-grade inflammation associated with chronic periodontitis is characterized by increased levels of circulating pro-inflammatory cytokines (IL-1, IL-6, tumor necrosis factor a) and C-reactive protein [4,5]. Similarly, low-grade inflammation is the hallmark characterizing adult obesity, with increased levels of plasma.Y gain-of-function mutations in the KCND3encoded Kv4.3 channels is the molecular pathogenesis for the lethal arrhythmia in patients with Brugada syndrome [30]. Suppression of ventricular arrhythmia in Brugada patients with quinidine [32,33] is believed to be related to its Ito blocking effect [34?6]. A recent study has reported that oxidation stress increases Ito conductance and promotes EADs (early after-depolarizations) by setting myocardial action potential plateau into the voltage range where ICa,L reactivation is facilitated and IKs activation is slowed, and the EADs are suppressed by the Ito blocker 4-AP [28]. It should be noted that Ito inhibition by 4-AP may restore the epicardial action potential dome, reduce both transmural and epicardial dispersion of repolarization, normalize the ST segment, and prevent phase 2 reentry and ventricular tachycardia/ ventricular fibrillation in experimental Brugada syndrome[15,31,37]. These studies suggest that Ito blockade also has a therapeutic effect on ventricular arrhythmias resulted from oxidation-induced EADs or Brugada syndrome. Acacetin has a strong inhibition of hKv4.3 current, and may also be a candidate drug in suppressing ventricular arrhythmias related to Brugada syndrome. Although acacetin also blocks hKv1.5 channels, this effect would not affect other phases of action potential in human ventricles, because no functional hKv1.5/IKur is present in ventricular myocytes of human hearts [38]. Blockade of hKv4.3 by acacetin would favor the correction of Brugada’s abnormal repolarization at early phase (phase 1) action potential in human ventricles; however, this remains further investigation in the future. Collectively, the present study demonstrates that acacetin mainly blocks hKv4.3 channels by binding to open states and interacting with T366 and T367 in the P-loop helix and V392, I395, and V399 within the S6 domain. The use- and frequencydependent blocking property of the hKv4.3 channels and also hKv1.5 channels suggest that this natural flavone compound could strongly inhibit atrial fibrillation. Further effort is required to study whether it is effective in managing ventricular arrhythmias related to Brugada Syndrome.Supporting InformationFigure S1 Effect of acacetin on closed-state inactivation of hKv4.3 channels. (PDF)Author ContributionsConceived and designed the experiments: GRL. Performed the experiments: HJW HYS WW YHZ. Analyzed the data: HJW HYS. Contributed reagents/materials/analysis tools: GWQ. Wrote the paper: HJW GRL.
Periodontitis comprises a group of multifactorial inflammatory diseases that affect the periodontium, i.e. the epithelial, connective and bone tissues that both surround and support the teeth [1]. From a pathophysiological point of view, inflammatory host mediators are involved in the detachment of the gingival connective tissue from the root surface, and in the resorption of alveolar bone supporting the tooth. The natural history of the disease leads to tooth loss. Chronic periodontitis is one of the most prevalent low-grade, bacterially induced, chronic inflammatory diseases affecting 20 to 50 of the adult population worldwide [2,3]. The low-grade inflammation associated with chronic periodontitis is characterized by increased levels of circulating pro-inflammatory cytokines (IL-1, IL-6, tumor necrosis factor a) and C-reactive protein [4,5]. Similarly, low-grade inflammation is the hallmark characterizing adult obesity, with increased levels of plasma.