National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture, Shanghai Ocean University, Shanghai 201306, China.
State Key Laboratory of NBC Protection for Civilian, Beijing 102205, China.
Fish Shellfish Immunol. 2024 Apr;147:109400. doi: 10.1016/j.fsi.2024.109400. Epub 2024 Jan 20.
Apoptosis is a physiological cell death phenomenon, representing one of the fundamental physiological mechanisms for maintaining homeostasis in living organisms. Previous studies have observed typical apoptotic features in Carassius auratus gibelio caudal fin cell (GiCF) infected with Cyprinid herpesvirus 2 (CyHV-2), and found a significant up-regulation of ccBAX expression in these infected cells. However, the specific apoptotic mechanism involved remains unclear. In this study, we utilized the GiCF cell line to investigate the apoptotic mechanism during CyHV-2 infection. Immunofluorescence staining revealed translocation of ccBAX into mitochondria upon CyHV-2 infection. Flow cytometry analysis demonstrated that overexpression of ccBAX expedited virus-induced apoptosis, characterized by heightened mitochondrial depolarization, increased transcriptional levels of Cytochrome c (Cyto c) in both the cytoplasm and mitochondria, and augmented Caspase 3/7 enzyme activity. Bax inhibitor peptide V5 (BIP-V5), an inhibitor interfering with the function of Bax proteins, inhibited Bax-mediated apoptotic events through the mitochondrial pathway and attenuated apoptosis induced by CyHV-2. In this study, it was identified for the first time that CyHV-2 induces apoptosis via the mitochondrial pathway in GiCF cells, bridging an important gap in our understanding regarding cell death mechanisms induced by herpesvirus infections in fish species. These findings provide a theoretical basis for comprehending viral apoptotic regulation mechanisms and the prevention and control of cellular pathologies caused by CyHV-2 infection.
细胞凋亡是一种生理性的细胞死亡现象，是生物体内维持内环境稳定的基本生理机制之一。先前的研究观察到感染鲤疱疹病毒 2（CyHV-2）的吉富罗非鱼尾鳍细胞（GiCF）中存在典型的凋亡特征，并发现这些感染细胞中 ccBAX 的表达显著上调。然而，具体的凋亡机制尚不清楚。本研究利用 GiCF 细胞系探讨了 CyHV-2 感染过程中的凋亡机制。免疫荧光染色显示，ccBAX 在 CyHV-2 感染后向线粒体易位。流式细胞术分析表明，ccBAX 的过表达加速了病毒诱导的细胞凋亡，表现为线粒体去极化增加、细胞质和线粒体中转录水平的 Cytochrome c（Cyto c）增加以及 Caspase 3/7 酶活性增强。Bax 抑制剂肽 V5（BIP-V5）是一种干扰 Bax 蛋白功能的抑制剂，通过线粒体途径抑制 Bax 介导的凋亡事件，并减轻 CyHV-2 诱导的细胞凋亡。本研究首次证实 CyHV-2 通过线粒体途径诱导 GiCF 细胞凋亡，填补了我们对鱼类疱疹病毒感染诱导细胞死亡机制的理解空白。这些发现为理解病毒凋亡调控机制以及预防和控制 CyHV-2 感染引起的细胞病理提供了理论依据。
