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.

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.

Infection with Zika virus (ZIKV) is a perinatal health problem and a vertical infection that promotes neurological fetal damage. ZIKV infects different cellular components at the maternal–fetal interface, including umbilical cord endothelial cells (HUVECs). Extracellular vesicles (EVs) are cellular components that mediate extracellular communication. Viruses have the capacity to hijack and modify the biogenesis machinery of EVs for their own benefit. The present work provides proteomic results (2D electrophoresis) that show the regulation of the expression of proteins involved in autophagy, oxidative stress, and exosome biogenesis in HUVECs infected with ZIKV. We confirmed that Alix and CD9 proteins were downregulated following the infection. Additionally, EVs isolated from infected cells showed the expression of Alix, and CD9 was increased in contrast to the mock condition. Interestingly, nanoparticle tracking and cryo-microscopy assays revealed that these EVs showed an increase in the quantity and size of ZIKV infection to differences in mock conditions. Furthermore, EVs isolated from infected cells showed infectivity, and both RNA and viral proteins were detected. Finally, our cryo-microscopy analysis revealed that the viral infection promoted morphological changes in these extracellular vesicles to identify vesicles with double and triple vesicles and electrodense and double membranes. In conclusion, our data suggest that ZIKV infection can modulate cellular factors involved in the formation and morphology of EVs in HUVECs. Furthermore, these EVs carry viral elements that may contribute to the dissemination of infection. Future studies aimed at the proteomic and lipidomic composition analyses of these EVs are needed to understand the biological implications in vertical infection.

Secreted viral proteins are crucial in virus–host interactions, as they modify the host microenvironment to promote infection. These secreted proteins could alter immune and inflammatory responses, allowing viruses to evade defense mechanisms such as cytotoxic T cell activation and antibody neutralization. Some secreted proteins mimic host molecules to suppress antiviral responses, making them valuable targets for antivirals and diagnostics. Notable examples include BARF1 from Epstein–Barr virus, associated with gastric cancer; vIL-10 from Epstein–Barr virus, which regulates immune responses and contributes to autoimmune diseases; NS1 from dengue virus, associated with vascular permeability and early diagnosis; and NSP4 from rotavirus as an enterotoxin, among others. The study of these proteins improves our understanding of viral pathogenesis and helps to develop innovative treatments for infectious and non-infectious diseases, taking advantage of the evolutionary adaptations of viruses. This review explores their impact on the infection cycle, disease progression, and key processes, such as cell cycle regulation, apoptosis, and cell signaling. Research on these proteins deepens our basic knowledge of virology and generates alternative methods for detecting biomarkers and creating more effective therapies, as well as implementing some emerging technologies, such as biosensors and plasmon resonance, for the diagnosis of viral diseases.