TPEN Prevents Rapid Pacing-Induced Calcium Overload and Nitration Stress in HL-1 Myocytes.

Cardiovascular therapeutics

PubMedID: 25973665

Yang S, Xu W, Dong Z, Zhou M, Lin C, Jin H, Su Y, Li Q, Wang X, Chang H, Han W. TPEN Prevents Rapid Pacing-Induced Calcium Overload and Nitration Stress in HL-1 Myocytes. Cardiovasc Ther. 2015;.
INTRODUCTION
Atrial fibrillation (AF) is the most common cardiac arrhythmia. However, the current drug interference of antiarrhythmia has limited efficacy and off-target effects. Accumulating evidence has implicated a potential role of nitration stress in the pathogenesis of AF. The aim of the study was to determine whether TPEN provided antinitration effects on atrial myocytes during AF, especially under circumstances of nitration stress.

METHODS
We utilized a rapid paced HL-1 cells model for AF. The changes of electrophysiological characteristics and structure of paced HL-1 cells were determined by a patch clamp and a TEM method. The effects of TPEN on pacing and ONOO(-) pretreated HL-1 cells were examined using MTT assay, TUNEL technique, confocal microscope experiment, and Western blot analysis.

RESULTS
The results revealed that ONOO(-) reduced the viability of HL-1 cells in a dose-dependent manner, and 1 µmol/L TPEN significantly ameliorated the damage caused by 50 µmol/L ONOO(-) (P < 0.05). Pacing and/or ONOO(-) -induced marked shortening of APD, myolysis, and nuclear condensation. TPEN inhibited the Ca(2+) overload induced by rapid pacing (P < 0.05) and ONOO(-) stimulation (P < 0.05). The application of TPEN significantly prevented the protein nitration caused by pacing or pacing plus ONOO(-) (P < 0.05). Additionally, pacing in combination with ONOO(-) treatment led to increase in apoptosis in HL-1 cells (P < 0.01), which could be reduced by pretreatment with TPEN (P < 0.05).

CONCLUSIONS
TPEN prevents Ca(2+) overload and nitration stress in HL-1 atrial myocytes during rapid pacing and circumstances of nitration stress.