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Dengue, transmitted by mosquitoes, can progress to severe symptoms like hemorrhagic fever and shock syndrome. While the virus and host immune response contribute to severity, other factors, such as small extracellular vesicles (sEVs), may play a role. sEVs mediate intercellular communication by transferring cellular components; however, their role infection remains unclear. We isolated and characterized sEVs from DENV-infected C6/36 mosquito cells, finding that they interact with mammalian cells and internalize the content. Using sEVs populations (with a size between 100 and 200 nm), we demonstrated enhanced infection in and murine models, including immunocompetent and immunosuppressed mice, which developed severe dengue-like symptoms. Our study reveals that sEVs from DENV-infected mosquito cells contribute to dengue pathogenesis, inducing severe symptoms in models, highlighting their potential role in disease progression and severe outcomes.

Recent studies have identified the brain circuits involved in the sleep/wake switch and have pointed to the modulation of neuronal excitability as one of the underlying mechanisms triggering sleep need. In this study we aimed to explore the link between the homeostatic regulation of neuronal excitability and sleep behavior in the circadian circuit. For this purpose, we selected Pumilio (Pum), whose main function is to repress protein translation and has been linked to modulation of neuronal excitability during chronic patterns of altered neuronal activity. Here we explore the effects of Pum on sleep homeostasis in , which shares most of the major features of mammalian sleep homeostasis. Our evidence indicates that Pum is necessary for sleep rebound and that its effect is more pronounced during chronic sleep deprivation (84 h) than acute deprivation (12 h). Knockdown of , results in a reduction of sleep rebound during acute sleep deprivation and the complete abolishment of sleep rebound during chronic sleep deprivation. Based on these findings, we propose that Pum is a critical regulator of sleep homeostasis through neural adaptations triggered during sleep deprivation.

Recent research has added a wealth of knowledge towards our understanding of the molecular and cellular mechanisms regulating sleep. However, the mechanisms responsible for compensatory sleep —specifically those elicited in response to long-term (chronic) sleep deprivation— remain largely unexplored. In this study, we show for the first time that the translational repressor Pumilio is an important regulator of the compensatory sleep homeostasis. Moreover, this is the first study in Drosophila exploring the compensatory mechanisms of chronic sleep deprivation, as opposed to acute deprivation. We demonstrate that the response elicited by acute and chronic sleep deprivation are indeed different—both behaviorally and molecularly. In addition, we demonstrate that Pumilio also regulates the homeostatic response to temperature increase during sleep. Furthermore, we provide evidence supporting the notion that translational regulation, effected through the target of Rapamycin (TOR) pathway, also play a relevant role in compensatory sleep regulation. Given the high prevalence of chronic sleep deprivation in our society, its wide range of negative consequences, and the evolutionary conservation of Pumilio, we believe that our findings are quite important and of great interest to the scientific community.

Recent studies have identified the Drosophila brain circuits involved in the sleep/wake switch and have pointed to the modulation of neuronal excitability as one of the underlying mechanisms triggering sleep need. In this study we aimed to explore the link between the homeostatic regulation of neuronal excitability and sleep behavior in the circadian circuit. For this purpose, we selected the neuronal homeostasis protein Pumilio (Pum), whose main function is to repress protein translation and has been linked to modulation of neuronal excitability during chronic patterns of altered neuronal activity. Here we explore the effects of Pum on sleep homeostasis in Drosophila melanogaster, which shares most of the major features of mammalian sleep homeostasis. Our evidence indicates that Pum is necessary for sleep rebound and that its effect is more pronounced during chronic sleep deprivation (84 hours) than acute deprivation (12 hours). Knockdown of pum, results in a reduction of sleep rebound during acute sleep deprivation and the complete abolishment of sleep rebound during chronic sleep deprivation. These behavioral changes were associated with accompanying changes in the expression of genes involved in the regulation of neuronal excitability. Interestingly, pum knockdown also increased baseline daytime sleep, suggesting that Pum differentially regulates rebound and normal sleep. Based on these findings, we propose that Pum is a critical regulator of sleep homeostasis through neural adaptations triggered during sleep deprivation and induces rebound sleep by altering neuronal excitability.

Engineered outer membrane vesicles (OMVs) derived from Gram-negative bacteria are a promising technology for the creation of non-infectious, nanoparticle vaccines against diverse pathogens. However, antigen display on OMVs can be difficult to control and highly variable due to bottlenecks in protein expression and localization to the outer membrane of the host cell, especially for bulky and/or complex antigens. Here, we describe a universal approach for avidin-based vaccine antigen crosslinking (AvidVax) whereby biotinylated antigens are linked to the exterior of OMVs whose surfaces are remodeled with multiple copies of a synthetic antigen-binding protein (SNAP) comprised of an outer membrane scaffold protein fused to a biotin-binding protein. We show that SNAP-OMVs can be readily decorated with a molecularly diverse array of biotinylated subunit antigens, including globular and membrane proteins, glycans and glycoconjugates, haptens, lipids, and short peptides. When the resulting OMV formulations are injected in mice, strong antigen-specific antibody responses are observed that depend on the physical coupling between the antigen and SNAP-OMV delivery vehicle. Overall, these results demonstrate AvidVax as a modular platform that enables rapid and simplified assembly of antigen-studded OMVs for application as vaccines against pathogenic threats. Antigen display on outer membrane vesicles (OMVs) can be difficult to control and highly variable. Here, the authors describe a universal approach called AvidVax for linking biotinylated antigens to the exterior of OMVs and enabling rapid vaccine assembly.