Department of Biological Sciences, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon, 34134, South Korea.
MOGAM Institute for Biomedical Research, 93, 30beon-gil, Ihyeon-ro, Gilheung-gu, Yongin-si, Gyeonggi-do, 16924, South Korea.
Cell Commun Signal. 2018 Sep 10;16(1):56. doi: 10.1186/s12964-018-0265-7.
Aberrant cell death induced by ischemic stress is implicated in the pathogenesis of ischemic diseases. Fas-associated factor 1 (FAF1) has been identified as a death-promoting protein. This study demonstrates that FAF1 functions in death signaling triggered by ischemic insult.
The expression changes of FAF1 and phophorylated JNK1 were detected by Western blotting. Immunoprecipitation was employed to investigate protein-protein interaction. We determined the cell death using flow cytometry and lactate dehydrogenase release measurement. To validate the death-promoting role of FAF1 in the retina, we generated conditional retinal FAF1 knockout mice. We used hematoxylin and eosin staining to detect retinal cell death in retinal ganglion cell layer.
FAF1 was found to function upstream of c-Jun N-terminal kinase 1 (JNK1), followed by mitochondrial dysregulation and necrotic cell death processes upon ischemic insult. We investigated whether FAF1 is involved in the pathogenesis of ischemic diseases using a retinal ischemia model. Indeed, FAF1 potentiated necrosis through JNK1 activation upon ischemic stress in retinal cells demonstrating retinal ganglion-like character. Conditional FAF1 depletion attenuated JNK1 activation in the retinas of Dkk3-Cre;Faf1 mice and ameliorated death of retinal cells due to elevated intraocular pressure (IOP).
Our results show that FAF1 plays a key role in ischemic retinal damage and may be implicated in the pathogenesis of retinal ischemic disease.
缺血性应激诱导的异常细胞死亡与缺血性疾病的发病机制有关。Fas 相关因子 1（FAF1）已被确定为一种促进死亡的蛋白。本研究表明，FAF1 在缺血性损伤引发的死亡信号中起作用。
通过 Western blot 检测 FAF1 和磷酸化 JNK1 的表达变化。采用免疫沉淀法研究蛋白质-蛋白质相互作用。通过流式细胞术和乳酸脱氢酶释放测定来确定细胞死亡。为了验证 FAF1 在视网膜中的促死亡作用，我们生成了条件性视网膜 FAF1 敲除小鼠。我们使用苏木精和伊红染色检测视网膜神经节细胞层中的视网膜细胞死亡。
发现 FAF1 在 c-Jun N 端激酶 1（JNK1）上游起作用，随后在缺血性损伤后发生线粒体失调和坏死性细胞死亡过程。我们使用视网膜缺血模型研究 FAF1 是否参与缺血性疾病的发病机制。事实上，FAF1 通过 JNK1 激活增强了视网膜细胞中的坏死作用，表现出类似于视网膜神经节的特征。条件性 FAF1 缺失可减轻 Dkk3-Cre；Faf1 小鼠视网膜中 JNK1 的激活，并减轻因眼内压升高而导致的视网膜细胞死亡。
我们的结果表明，FAF1 在缺血性视网膜损伤中起关键作用，可能与视网膜缺血性疾病的发病机制有关。
