Prenatal delivery of a therapeutic antisense oligonucleotide achieves broad biodistribution in the brain and ameliorates Angelman syndrome phenotype in mice.

Angelman syndrome (AS), an early-onset neurodevelopmental disorder characterized by abnormal gait, intellectual disabilities, and seizures, occurs when the maternal allele of the UBE3A gene is disrupted, since the paternal allele is silenced in neurons by the UBE3A antisense (UBE3A-AS) transcript. Given the importance of early treatment, we hypothesized that prenatal delivery of an antisense oligonucleotide (ASO) would downregulate the murine Ube3a-AS, resulting in increased UBE3A protein and functional rescue. Using a mouse model with a Ube3a-YFP allele that reports on-target ASO activity, we found that in utero, intracranial (IC) injection of the ASO resulted in dose-dependent activation of paternal Ube3a, with broad biodistribution. Accordingly, in utero injection of the ASO in a mouse model of AS also resulted in successful restoration of UBE3A and phenotypic improvements in treated mice on the accelerating rotarod and fear conditioning. Strikingly, even intra-amniotic (IA) injection resulted in systemic biodistribution and high levels of UBE3A reactivation throughout the brain. These findings offer a novel strategy for early treatment of AS using an ASO, with two potential routes of administration in the prenatal window. Beyond AS, successful delivery of a therapeutic ASO into neurons has implications for a clinically feasible prenatal treatment for numerous neurodevelopmental disorders.

Compliance with face mask use during the COVID-19 pandemic: a community observational study in Singapore.

Introduction: Widespread mask use is an important intervention for control of the coronavirus disease 2019 pandemic. However, data on the factors affecting mask use are lacking. In this observational study, we evaluated the proportion of and factors influencing face mask use and related hygiene practices. Methods: We observed randomly selected members from the public in 367 venues across Singapore, and recorded the proportion of individuals with full compliance with mask use and mask hygiene (hand hygiene before and after touching the mask or face). Logistic regression analyses were used to determine variables associated with mask and hand hygiene compliance. Results: We made 3,821 observations - 2,149 (56.2%) females, 3,569 (93.4%) adults (≥21 years), 212 (5.5%) children (6-20 years) and 40 (1.0%) children (2-5 years). The overall full compliance rate (correct mask use), poor compliance rate (incorrect mask use) and absent mask use were 84.5%, 12.9% and 2.6%, respectively. The factors - male gender, fabric mask usage and crowded indoor venues - were associated with lower mask compliance. Face or mask touching behaviour was observed in 10.7% and 13.7% of individuals observed, respectively. Only one individual performed hand hygiene before and after touching the mask. Conclusion: The rate of mask compliance was high, probably due to legislation mandating mask usage. However, specific factors and crowded indoor venues associated with lower mask compliance were identified. We also noted an issue with the absence of hand hygiene before and after face or mask touching. These issues may benefit from targeted public health messaging.

Young mice administered adult doses of AAV5-hFVIII-SQ achieve therapeutic factor VIII expression into adulthood.

Valoctocogene roxaparvovec (AAV5-hFVIII-SQ) gene transfer provided reduced bleeding for adult clinical trial participants with severe hemophilia A. However, pediatric outcomes are unknown. Using a mouse model of hemophilia A, we investigated the effect of vector dose and age at treatment on transgene production and persistence. We dosed AAV5-hFVIII-SQ to neonatal and adult mice based on body weight or at a fixed dose and assessed human factor VIII-SQ variant (hFVIII-SQ) expression through 16 weeks. AAV5-hFVIII-SQ dosed per body weight in neonatal mice did not result in meaningful plasma hFVIII-SQ protein levels in adulthood. When treated with the same total vector genomes per mouse as adult mice, neonates maintained hFVIII-SQ expression into adulthood, although plasma levels were 3- to 4-fold lower versus mice dosed as adults. Mice <1 week old initially exhibited high hFVIII-SQ plasma levels and maintained meaningful levels into adulthood, despite a partial decline potentially due to age-related body mass and blood volume increases. Spatial transduction patterns differed between mice dosed as neonates versus adults. No features of hepatotoxicity or endoplasmic reticulum stress were observed with dosing at any age. These data suggest that young mice require the same total vector genomes as adult mice to sustain hFVIII-SQ plasma levels.

Baseline immunoreactivity before pregnancy and poly(I:C) dose combine to dictate susceptibility and resilience of offspring to maternal immune activation.

Despite the potential of rodent models of maternal immune activation (MIA) to identify new biomarkers and therapeutic interventions for a range of psychiatric disorders, current approaches using these models ignore two of the most important aspects of this risk factor for human disease: (i) most pregnancies are resilient to maternal viral infection and (ii) susceptible pregnancies can lead to different combinations of phenotypes in offspring. Here, we report two new sources of variability-the baseline immunoreactivity (BIR) of isogenic females prior to pregnancy and differences in immune responses in C57BL/6 dams across vendors-that contribute to resilience and susceptibility to distinct combinations of behavioral and biological outcomes in offspring. Similar to the variable effects of human maternal infection, MIA in mice does not cause disease-related phenotypes in all pregnancies and a combination of poly(I:C) dose and BIR predicts susceptibility and resilience of pregnancies to aberrant repetitive behaviors and alterations in striatal protein levels in offspring. Even more surprising is that the intermediate levels of BIR and poly(I:C) dose are most detrimental to offspring, with higher BIR and poly(I:C) doses conferring resilience to measured phenotypes in offspring. Importantly, we identify the BIR of female mice as a biomarker before pregnancy that predicts which dams will be most at risk as well as biomarkers in the brains of newborn offspring that correlate with changes in repetitive behaviors. Together, our results highlight considerations for optimizing MIA protocols to enhance rigor and reproducibility and reveal new factors that drive susceptibility of some pregnancies and resilience of others to MIA-induced abnormalities in offspring.

Discrete element modelling of sediment falling in water.

The Discrete Element Method (DEM) is a discrete, particle-based method commonly used in studies involving granular media, e.g. sediment transport, and geomechanics. It is heavily dependent on particle properties, and one important component is the force model, which relates the relative positions and velocities of the simulated particles to the forces they experience. In this paper we model a collection of lightly compacted granular material, released at a short distance above a flat base in a quiescent fluid --similar to the process whereby sediment tailings are released back into the sea during nodule harvesting. We employ different typical force models, and consider how their varying components affect the simulated outcome. The results are compared with a physical experiment of similar dimensions. We find that a realistic simulation is achieved when the force model considers the local solid fraction in the drag force, and incorporates the hydrodynamic effect of neighbouring particles. The added mass effect increases the accuracy of the outcome, but does not contribute significantly in a qualitative sense.