Mitochondria are dynamic organelles that play crucial roles in energy production, metabolic balance, calcium homeostasis, apoptosis, and innate immunity, and are key determinants of cell fate. They are also targets for viral invasion of the body. Many viral proteins target mitochondria, controlling mitochondrial morphology, metabolism, and immune response, thereby achieving immune evasion, promoting their proliferation, and accelerating the infection process. Mitochondrial quality control is key to maintaining normal physiological functions and mitochondrial homeostasis. Dysregulation of mitochondrial dynamics is closely related to the development of many diseases. New roles of mitochondrial dynamics in viral infection are constantly being discovered. Viruses change mitochondrial dynamics by targeting mitochondria to achieve a persistent state of infection. Currently, understanding of mitochondrial dynamics during viral infection is limited. Research on the impact of viral proteins on mitochondrial dynamics provides a foundation for investigating the pathogenesis of viral infections, the disease process, and identifying potential therapeutic targets. This review focuses on the connection between viral infection and mitochondrial dynamics and priority areas for research on virus-mediated mitochondrial immunity, provides insight into the regulation of mitochondrial dynamics by viruses targeting mitochondria, and explores potential means of mitochondrial-mediated control and treatment of viral diseases.

Zhao L, et al. J Vet Sci. 2021 Aug;22(6):e66. https://doi.org/10.4142/jvs.2021.22.e66

The primary sheep trophoblast cells (STCs) have a finite lifespan in culture. This feature limits the scope for long-termin vitrostudies with STCs. This study was an attempt to establish and characterize a telomerase-immortalized sheep trophoblast cell line. STCs were isolated and purified by using Percoll and specific immunoaffinity purification, respectively. The purified STCs were transfected with a plasmid carrying sequences of human telomerase reverse transcriptase (hTERT) to create immortalized sheep trophoblast cell line (hTERT-STCs). hTERT-STCs showed a stable expression of hTERT gene, serially passaged for a year, and showed active proliferation without signs of senescence. Cytokeratin 7 (CK-7), secreted human chorionic gonadotrophin subunitβ(CG-β), placental lactogen (PL), and endogenous jaagsiekte sheep retrovirus (enJSRV) envelope genes were expressed in hTERT-STCs. Transwell cell invasion assay indicated that hTERT-STCs still possessed the same invasive characteristics as normal primary sheep trophoblast cells. hTERT-STCs could not grow in soft agar and did not develop into tumors in nude mice. In this study, we established a strain of immortalized sheep trophoblast cell line which could be gainfully employed in the future as an experimental model to study trophoblast cells with secretory function, invasive features, and probable biological function of enJSRV envelope genes.

The envelope protein (Env) of the Jaagsiekte sheep retrovirus (JSRV) is known to be a unique oncoprotein responsible for inducing ovine pulmonary adenocarcinoma (OPA). The objective of this study was to prepare a specific monoclonal antibody (mAb) against the JSRV Env protein using bioinformatic analysis. According to the structure and epitope prediction results of JSRV Env, the JSRV-Env_572-615 antigen was prepared via peptide synthesis (amino acid sequence 572-615, denoted as JSRV-Env_572-615). BALB/c mice were immunized to prepare the anti-JSRV-Env_572-615 mAb. Spleen cells were fused with SP2/0 myeloma cells after being screened by indirect ELISA and cloned by limiting dilution. The specificity of mAb was evaluated by western blot analysis and immunohistochemistry assays. Western blot results showed that the JSRV Env protein was able to bind to mAb with high specificity. Immunohistochemistry assays demonstrated that the mAb was able to recognize JSRV Env in adenomatous hyperplasia of the lung. Furthermore, JSRV was detected in peripheral blood leukocytes during the pre-clinical period of OPA in 2 of the 25 sheep using this newly synthesized mAb. Therefore, this mAb may be a useful tool for the detection of JSRV in sheep.