MSC-mediated mitochondrial transfer restores mitochondrial DNA and function in neural progenitor cells of Leber's hereditary optic neuropathy.

Leber's hereditary optic neuropathy (LHON) is a debilitating mitochondrial disease associated with mutations in mitochondrial DNA (mtDNA). Unfortunately, the available treatment options for LHON patients are limited due to challenges in mitochondrial replacement. In our study, we reprogramming LHON urine cells into induced pluripotent stem cells (iPSCs) and differentiating them into neural progenitor cells (NPCs) and neurons for disease modeling. Our research revealed that LHON neurons exhibited significantly higher levels of mtDNA mutations and reduced mitochondrial function, confirming the disease phenotype. However, through co-culturing LHON iPSC-derived NPCs with mesenchymal stem cells (MSCs), we observed a remarkable rescue of mutant mtDNA and a significant improvement in mitochondrial metabolic function in LHON neurons. These findings suggest that co-culturing with MSCs can enhance mitochondrial function in LHON NPCs, even after their differentiation into neurons. This discovery holds promise as a potential therapeutic strategy for LHON patients.

Molecular anatomy of the subcellular localization and nuclear import mechanism of herpes simplex virus 1 UL6.

As an indispensable structure protein, the herpes simplex virus 1 (HSV-1) UL6 has been described to exert numerous roles in viral proliferation. However, its exact subcellular localization and subcellular transport mechanism is not well known. In the present study, by utilizing confocal fluorescent microscopy, UL6 was shown to mainly locate in the nucleus in enhanced yellow fluorescent protein or Flag tag fused expression plasmid-transfected cells or HSV-1-infected cells, whereas its predicted nuclear localization signal was nonfunctional. In addition, by exploiting dominant negative mutant and inhibitor of different nuclear import receptors, as well as co-immunoprecipitation and RNA interference assays, UL6 was established to interact with importin α1, importin α7 and transportin-1 to mediate its nuclear translocation under the help of Ran-mediated GTP hydrolysis. Accordingly, these results will advance the knowledge of UL6-mediated biological significances in HSV-1 infection cycle.

Epstein-Barr Virus Early Protein BFRF1 Suppresses IFN-ß Activity by Inhibiting the Activation of IRF3.

Epstein-Barr virus (EBV) is the causative agent of infectious mononucleosis that is closely associated with several human malignant diseases, while type I interferon (IFN-I) plays an important role against EBV infection. As we all know, EBV can encode some proteins to inhibit the production of IFN-I, but it's not clear whether other proteins also take part in this progress. EBV early lytic protein BFRF1 is shown to be involved in viral maturation, however, whether BFRF1 participates in the host innate immune response is still not well known. In this study, we found BFRF1 could down-regulate sendai virus-induced IFN-ß promoter activity and mRNA expression of IFN-ß and ISG54 during BFRF1 plasmid transfection and EBV lytic infection, but BFRF1 could not affect the promoter activity of NF-κB or IRF7. Specifically, BFRF1 could co-localize and interact with IKKi. Although BFRF1 did not interfere the interaction between IKKi and IRF3, it could block the kinase activity of IKKi, which finally inhibited the phosphorylation, dimerization, and nuclear translocation of IRF3. Taken together, BFRF1 may play a critical role in disrupting the host innate immunity by suppressing IFN-ß activity during EBV lytic cycle.

Expression, Purification, and Antiserum Production of the Truncated UL31 Protein of Herpes Simplex Virus 1.

BACKGROUND: The UL31 protein of herpes simplex virus 1 (HSV-1) plays an important role in the HSV-1 replication, however, its pinpoint functions in the life cycle of the virus have yet to be adequately elucidated. OBJECTIVES: An antiserum specific for detecting HSV-1 UL31 was prepared as the foundation for future research on the role of UL31 in the course of HSV-1 infection. MATERIALS AND METHODS: Recombinant protein of UL31 was expressed in Escherichia coli, which was then purified and employed to raise the level of antiserum in mice. Subsequently, western blot and immunofluorescence assay (IFA) were utilized to detect the specific antiserum. RESULTS: The recombinant UL31 protein consisting of N-terminal 27 aa of UL31 was fused to EYFP and His-tag. It was expressed, purified, and applied to the preparation of the antiserum. Western blot analysis and IFA demonstrated that this antiserum could detect both the recombinant UL31 and the native UL31. CONCLUSIONS: Our results manifest that this antiserum could be conducive to further investigations concerning the roles of UL31 in the HSV-1 infection.