The Transcription Factor ATF4 Promotes Expression of Cell Stress Genes and Cardiomyocyte Death in a Cellular Model of Atrial Fibrillation

Figure 1

ATF4 expression in H₂O₂ and thapsigargin treated cardiomyocytes and in electrically stimulated cardiomyocytes. (a) Real-time PCR of ATF4 mRNA expression in cultured HL-1 cardiomyocytes in response to treatment with 0, 0.05, or 0.1 μl/ml H₂O₂ (), real-time PCR of ATF4 mRNA expression in cultured cardiomyocytes in response to treatment with 1 μM thapsigargin (), and real-time PCR of cardiomyocytes stimulated electrically with 4 Hz for 20 h (). Representative western blots showing protein expression of ATF4 in response to H₂O₂ treatment (b) and in response to thapsigargin treatment (c). (d) Cardiomyocytes were electrically stimulated with 4 Hz for 20 h and ATF4 protein expression was detected. (e) MTT assay displaying viability of cardiomyocytes treated with H₂O₂ (), 1 μM thapsigargin (), and paced HL-1 cardiomyocytes (). indicates .