Department of Internal Medicine B, University Medicine Greifswald, Greifswald, Germany.
J Cell Biochem. 2014 Apr;115(4):678-89. doi: 10.1002/jcb.24707.
Auto-antibodies against cardiac proteins have been described in patients with dilated cardiomyopathy. Antibodies against the C-terminal part of KChIP2 (anti-KChIP2 [C-12]) enhance cell death of rat cardiomyocytes. The underlying mechanisms are not fully understood. Therefore, we wanted to explore the mechanisms responsible for anti-KChIP2-mediated cell death. Rat cardiomyocytes were treated with anti-KChIP2 (C-12). KChIP2 RNA and protein expressions, nuclear NF-κB, mitochondrial membrane potential Δψm, caspase-3 and -9 activities, necrotic and apoptotic cells, total Ca(2+) and K(+) concentrations, and the effects on L-type Ca(2+) channels were quantified. Anti-KChIP2 (C-12) induced nuclear translocation of NF-κB. Anti-KChIP2 (C-12)-treatment for 2 h significantly reduced KChIP2 mRNA and protein expression. Anti-KChIP2 (C-12) induced nuclear translocation of NF-κB after 1 h. After 6 h, Δψm and caspase-3 and -9 activities were not significantly changed. After 24 h, anti-KChIP2 (C-12)-treated cells were 75 ± 3% necrotic, 2 ± 1% apoptotic, and 13 ± 2% viable. Eighty-six ± 1% of experimental buffer-treated cells were viable. Anti-KChIP2 (C-12) induced significant increases in total Ca(2+) (plus 11 ± 2%) and K(+) (plus 18 ± 2%) concentrations after 5 min. Anti-KChIP2 (C-12) resulted in an increased Ca(2+) influx through L-type Ca(2+) channels. In conclusion, our results suggest that anti-KChIP2 (C-12) enhances cell death of rat cardiomyocytes probably due to necrosis.
自身抗体针对心脏蛋白已被描述在扩张型心肌病患者。抗体对 KChIP2 的 C 末端部分（抗 KChIP2 [C-12]）增强大鼠心肌细胞的细胞死亡。其潜在的机制尚未完全阐明。因此，我们想探讨负责抗 KChIP2 介导的细胞死亡的机制。大鼠心肌细胞用抗 KChIP2（C-12）处理。KChIP2 RNA 和蛋白质表达、核 NF-κB、线粒体膜电位Δψm、半胱天冬酶-3 和 -9 的活性、坏死和凋亡细胞、总 Ca（2+）和 K（+）浓度，以及对 L-型 Ca（2+）通道的影响进行了定量。抗 KChIP2（C-12）诱导核易位的 NF-κB。抗 KChIP2（C-12）治疗 2 小时显著降低 KChIP2 mRNA 和蛋白质表达。抗 KChIP2（C-12）诱导核易位的 NF-κB 在 1 小时后。6 小时后，Δψm 和 caspase-3 和 -9 的活性没有明显变化。24 小时后，抗 KChIP2（C-12）处理的细胞是 75 ± 3%坏死，2 ± 1%凋亡，和 13 ± 2%存活。86 ± 1%的实验缓冲液处理的细胞是存活的。抗 KChIP2（C-12）诱导的总 Ca（2+）显著增加（增加 11 ± 2%）和 K（+）（增加 18 ± 2%）浓度后 5 分钟。抗 KChIP2（C-12）导致 L-型 Ca（2+）通道通过增加 Ca（2+）内流。总之，我们的结果表明，抗 KChIP2（C-12）增强大鼠心肌细胞的死亡可能是由于坏死。
