Salvador-Mira Maria, Sanchez-Cordoba Ester, Solivella Manuel, Nombela Ivan, Puente-Marin Sara, Chico Veronica, Perez Luis, Perez-Berna Ana Joaquina, Ortega-Villaizan Maria Del Mar
Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández (IDiBE-UMH), Elche, Spain.
MISTRAL Beamline Experiments Division, ALBA Synchrotron Light Source, Barcelona, Spain.
Front Immunol. 2024 Nov 26;15:1466870. doi: 10.3389/fimmu.2024.1466870. eCollection 2024.
Fish nucleated red blood cells (RBCs), also known as erythrocytes, play a crucial role in maintaining immune system balance by modulating protein expression in response to various stimuli, including viral attack. This study explores the intriguing behavior of rainbow trout RBCs when faced with the viral hemorrhagic septicemia virus (VHSV), focusing on the endoplasmic reticulum (ER) stress and the unfolded protein response (UPR).
Rainbow trout RBCs were Ficoll-purified and exposed to ultraviolet (UV)-inactivated VHSV or live VHSV at different multiplicities of infection (MOIs). Using cryo-soft X-ray tomography (cryo-SXT), we uncovered structural and cellular modifications in RBCs exposed to UV-inactivated VHSV. Moreover, RBCs were treated with 4-phenylbutyric acid (4-PBA), an ER stress inhibitor, to investigate its effect on viral replication. Quantitative real-time PCR was also used to analyze the expression of genes related to the UPR and other related cellular pathways.
Beyond their antiviral response, RBCs undergo notable intracellular changes to combat the virus. Cryo-SXT highlighted a significant increase in the ER volume. This increase is associated with ER stress and the activation of the UPR pathway. Interestingly, VHSV replication levels augmented in RBCs under ER-stress inhibition by 4-PBA treatment, suggesting that rainbow trout RBCs tune up ER stress to control viral replication. Therefore, our findings suggested the induction of ER stress and subsequent activation UPR signaling in the antiviral response of RBCs to VHSV. The results open a new line of investigation to uncover additional mechanisms that may become novel cellular targets for the development of RBC-targeted antiviral strategies.
鱼类有核红细胞（RBCs），也称为红细胞，通过响应包括病毒攻击在内的各种刺激来调节蛋白质表达，在维持免疫系统平衡中发挥着关键作用。本研究探讨了虹鳟有核红细胞在面对病毒性出血性败血症病毒（VHSV）时的有趣行为，重点关注内质网（ER）应激和未折叠蛋白反应（UPR）。
虹鳟有核红细胞经Ficoll纯化，并以不同的感染复数（MOIs）暴露于紫外线（UV）灭活的VHSV或活的VHSV。使用低温软X射线断层扫描（cryo-SXT），我们发现了暴露于UV灭活VHSV的有核红细胞中的结构和细胞变化。此外，用内质网应激抑制剂4-苯基丁酸（4-PBA）处理有核红细胞，以研究其对病毒复制的影响。定量实时PCR也用于分析与未折叠蛋白反应和其他相关细胞途径相关的基因表达。
除了抗病毒反应外，有核红细胞还会发生显著的细胞内变化以对抗病毒。低温软X射线断层扫描突出显示内质网体积显著增加。这种增加与内质网应激和未折叠蛋白反应途径的激活有关。有趣的是，在4-PBA处理抑制内质网应激的情况下，有核红细胞中的VHSV复制水平增加，这表明虹鳟有核红细胞通过调节内质网应激来控制病毒复制。因此我们的研究结果表明，在有核红细胞对VHSV的抗病毒反应中诱导了内质网应激并随后激活了未折叠蛋白反应信号。这些结果开辟了一条新的研究途径，以揭示可能成为红细胞靶向抗病毒策略开发新细胞靶点的其他机制。
