The Nucleolus and Its Interactions with Viral Proteins Required for Successful Infection.

Nuclear bodies are structures in eukaryotic cells that lack a plasma membrane and are considered protein condensates, DNA, or RNA molecules. Known nuclear bodies include the nucleolus, Cajal bodies, and promyelocytic leukemia nuclear bodies. These bodies are involved in the concentration, exclusion, sequestration, assembly, modification, and recycling of specific components involved in the regulation of ribosome biogenesis, RNA transcription, and RNA processing. Additionally, nuclear bodies have been shown to participate in cellular processes such as the regulation of transcription of the cell cycle, mitosis, apoptosis, and the cellular stress response. The dynamics and functions of these bodies depend on the state of the cell. It is now known that both DNA and RNA viruses can direct their proteins to nuclear bodies, causing alterations in their composition, dynamics, and functions. Although many of these mechanisms are still under investigation, it is well known that the interaction between viral and nuclear body proteins is necessary for the success of the viral infection cycle. In this review, we concisely describe the interaction between viral and nuclear body proteins. Furthermore, we focus on the role of the nucleolus in RNA virus infections. Finally, we discuss the possible implications of the interaction of viral proteins on cellular transcription and the formation/degradation of non-coding RNAs.

Metformin Inhibits Zika Virus Infection in Trophoblast Cell Line.

Zika virus (ZIKV) infections have been associated with severe clinical outcomes, which may include neurological manifestations, especially in newborns with intrauterine infection. However, licensed vaccines and specific antiviral agents are not yet available. Therefore, a safe and low-cost therapy is required, especially for pregnant women. In this regard, metformin, an FDA-approved drug used to treat gestational diabetes, has previously exhibited an anti-ZIKA effect in vitro in HUVEC cells by activating AMPK. In this study, we evaluated metformin treatment during ZIKV infection in vitro in a JEG3-permissive trophoblast cell line. Our results demonstrate that metformin affects viral replication and protein synthesis and reverses cytoskeletal changes promoted by ZIKV infection. In addition, it reduces lipid droplet formation, which is associated with lipogenic activation of infection. Taken together, our results indicate that metformin has potential as an antiviral agent against ZIKV infection in vitro in trophoblast cells.

Multifaceted Nature of Lipid Droplets in Viral Interactions and Pathogenesis.

Once regarded as inert organelles with limited and ill-defined roles, lipid droplets (LDs) have emerged as dynamic entities with multifaceted functions within the cell. Recent research has illuminated their pivotal role as primary energy reservoirs in the form of lipids, capable of being metabolized to meet cellular energy demands. Their high dynamism is underscored by their ability to interact with numerous cellular organelles, notably the endoplasmic reticulum (the site of LD genesis) and mitochondria, which utilize small LDs for energy production. Beyond their contribution to cellular bioenergetics, LDs have been associated with viral infections. Evidence suggests that viruses can co-opt LDs to facilitate their infection cycle. Furthermore, recent discoveries highlight the role of LDs in modulating the host's immune response. Observations of altered LD levels during viral infections suggest their involvement in disease pathophysiology, potentially through production of proinflammatory mediators using LD lipids as precursors. This review explores these intriguing aspects of LDs, shedding light on their multifaceted nature and implications in viral interactions and disease development.