Ribosome-Associated Vesicles promote activity-dependent local translation.

Local protein synthesis in axons and dendrites underpins synaptic plasticity. However, the composition of the protein synthesis machinery in distal neuronal processes and the mechanisms for its activity-driven deployment to local translation sites remain unclear. Here, we employed cryo-electron tomography, volume electron microscopy, and live-cell imaging to identify Ribosome-Associated Vesicles (RAVs) as a dynamic platform for moving ribosomes to distal processes. Stimulation via chemically-induced long-term potentiation causes RAV accumulation in distal sites to drive local translation. We also demonstrate activity-driven changes in RAV generation and dynamics in vivo, identifying tubular ER shaping proteins in RAV biogenesis. Together, our work identifies a mechanism for ribosomal delivery to distal sites in neurons to promote activity-dependent local translation.

Inhibiting influenza virus transmission using a broadly acting neuraminidase that targets host sialic acids in the upper respiratory tract.

The ongoing transmission of influenza A viruses (IAV) for the past century continues to be a burden to humans. IAV binds terminal sialic acids (SA) of sugar molecules present within the upper respiratory tract (URT) in order to successfully infect hosts. The two most common SA structures that are important for IAV infection are those with α2,3- and α2,6-linkages. While mice were once considered to be an unsuitable system for studying IAV transmission due to their lack of α2,6-SA in the trachea, we have successfully demonstrated that IAV transmission in infant mice is remarkably efficient. This finding led us to re-evaluate the SA composition of the URT of mice using in situ immunofluorescence and examine its in vivo contribution to transmission for the first time. We demonstrate that mice express both α2,3- and α2,6-SA in the URT and that the difference in expression between infants and adults contributes to the variable transmission efficiencies observed. Furthermore, selectively blocking α2,3-SA or α2,6-SA within the URT of infant mice using lectins was necessary but insufficient at inhibiting transmission, and simultaneous blockade of both receptors was crucial in achieving the desired inhibitory effect. By employing a broadly acting neuraminidase to indiscriminately remove both SA moieties in vivo, we effectively suppressed viral shedding and halted the transmission of different strains of influenza viruses. These results emphasize the utility of the infant mouse model for studying IAV transmission and strongly indicate that broadly targeting host SA is an effective approach that inhibits IAV contagion.IMPORTANCEInfluenza virus transmission studies have historically focused on viral mutations that alter hemagglutinin binding to sialic acid (SA) receptors in vitro. However, SA binding preference does not fully account for the complexities of influenza A virus transmission in humans. Our previous findings reveal that viruses that are known to bind α2,6-SA in vitro have different transmission kinetics in vivo, suggesting that diverse SA interactions may occur during their life cycle. In this study, we examine the role of host SA on viral replication, shedding, and transmission in vivo. We highlight the critical role of SA presence during virus shedding, such that attachment to SA during virion egress is equally important as detachment from SA during virion release. These insights support the potential of broadly acting neuraminidases as therapeutic agents capable of restraining viral transmission in vivo. Our study unveils intricate virus-host interactions during shedding, highlighting the necessity to develop innovative strategies to effectively target transmission.

Targeting host sialic acids in the upper respiratory tract with a broadly-acting neuraminidase to inhibit influenza virus transmission.

The ongoing transmission of influenza A viruses (IAV) for the past century continues to be a burden to humans. IAV binds terminal sialic acids (SA) of sugar molecules present within the upper respiratory tract (URT) in order to successfully infect hosts. The two most common SA structures that are important for IAV infection are those with α2,3- and α2,6-linkages. While mice were once considered to be an unsuitable system for studying IAV transmission due to their lack of α2,6-SA in the trachea, we have successfully demonstrated that IAV transmission in infant mice is remarkably efficient. This finding led us to reevaluate the SA composition of the URT of mice using in situ immunofluorescence and examine its in vivo contribution to transmission for the first time. We demonstrate that mice express both α2,3- and α2,6-SA in the URT and that the difference in expression between infants and adults contribute to the variable transmission efficiencies observed. Furthermore, selectively blocking α2,3-SA or α2,6-SA within the URT of infant mice using lectins was necessary but insufficient at inhibiting transmission, and simultaneous blockade of both receptors was crucial in achieving the desired inhibitory effect. By employing a broadly-acting neuraminidase (ba-NA) to indiscriminately remove both SA moieties in vivo, we effectively suppressed viral shedding and halted the transmission of different strains of influenza viruses. These results emphasize the utility of the infant mouse model for studying IAV transmission, and strongly indicate that broadly targeting host SA is an effective approach that inhibits IAV contagion.

Sleep and circadian defects in a Drosophila model of mitochondrial encephalomyopathy.

Mitochondrial encephalomyopathies (ME) are complex, incurable diseases characterized by severe bioenergetic distress that can affect the function of all major organ systems but is especially taxing to neuromuscular tissues. Animal models of MEs are rare, but the Drosophila ATP61 mutant is a stable, well-characterized genetic line that accurately models progressive human mitochondrial diseases such as Maternally-Inherited Leigh Syndrome (MILS), Neuropathy, Ataxia, and Retinitis Pigmentosa (NARP), and Familial Bilateral Striatal Necrosis (FBSN). While it is established that this model exhibits important hallmarks of ME, including excess cellular and mitochondrial reactive oxygen species, shortened lifespan, muscle degeneration, and stress-induced seizures, it is unknown whether it exhibits defects in sleep or circadian function. This is a clinically relevant question, as many neurological and neurodegenerative diseases are characterized by such disturbances, which can exacerbate other symptoms and worsen quality of life. Since Drosophila is highly amenable to sleep and circadian studies, we asked whether we could detect disease phenotypes in the circadian behaviors of ATP61 . Indeed, we found that day-time and night-time activity and sleep are altered through disease progression, and that circadian patterns are disrupted at both the behavioral and neuronal levels. These results establish ATP61 as an important model of sleep and circadian disruption in ME that can be studied mechanistically at the molecular, cellular, and behavioral level to uncover underlying pathophysiology and test novel therapies.