Divergent low-density lipoprotein receptor (LDLR) linked to low VSV G-dependent viral infectivity and unique serum lipid profile in zebra finches

Genomic loss of GPR108 disrupts AAV transduction in birds

The G protein-coupled receptor 108 (GPR108) gene encodes a protein factor identified as critical for adeno-associated virus (AAV) entry into mammalian cells, but whether it is universally involved in AAV transduction is unknown. Remarkably, we have discovered that GPR108 is absent in the genomes of birds and in most other sauropsids, providing a likely explanation for the overall lower AAV transduction efficacy of common AAV serotypes in birds compared to mammals. Importantly, transgenic expression of human GPR108 and manipulation of related glycan binding sites in the viral capsid significantly boost AAV transduction in zebra finch cells. These findings contribute to a more in depth understanding of the mechanisms and evolution of AAV transduction, with potential implications for the design of efficient tools for gene manipulation in experimental animal models, and a range of gene therapy applications in humans.

Pseudorabies virus upregulates low-density lipoprotein receptors to facilitate viral entry

Pseudorabies virus (PRV) is the causative agent of Aujeszky's disease in pigs. The low-density lipoprotein receptor (LDLR) is a transcriptional target of the sterol-regulatory element-binding proteins (SREBPs) and participates in the uptake of LDL-derived cholesterol. However, the involvement of LDLR in PRV infection has not been well characterized. We observed an increased expression level of LDLR mRNA in PRV-infected 3D4/21, PK-15, HeLa, RAW264.7, and L929 cells. The LDLR protein level was also upregulated by PRV infection in PK-15 cells and in murine lung and brain. The treatment of cells with the SREBP inhibitor, fatostatin, or with SREBP2-specific small interfering RNA prevented the PRV-induced upregulation of LDLR expression as well as viral protein expression and progeny virus production. This suggested that PRV activated SREBPs to induce LDLR expression. Furthermore, interference in LDLR expression affected PRV proliferation, while LDLR overexpression promoted it. This indicated that LDLR was involved in PRV infection. The study also demonstrated that LDLR participated in PRV invasions. The overexpression of LDLR or inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9), which binds to LDLR and targets it for lysosomal degradation, significantly enhanced PRV attachment and entry. Mechanistically, LDLR interacted with PRV on the plasma membrane, and pretreatment of cells with LDLR antibodies was able to neutralize viral entry. An in vivo study indicated that the treatment of mice with the PCSK9 inhibitor SBC-115076 promoted PRV proliferation. The data from the study indicate that PRV hijacks LDLR for viral entry through the activation of SREBPs.IMPORTANCEPseudorabies virus (PRV) is a herpesvirus that primarily manifests as fever, pruritus, and encephalomyelitis in various domestic and wild animals. Owing to its lifelong latent infection characteristics, PRV outbreaks have led to significant financial setbacks in the global pig industry. There is evidence that PRV variant strains can infect humans, thereby crossing the species barrier. Therefore, gaining deeper insights into PRV pathogenesis and developing updated strategies to contain its spread are critical. This study posits that the low-density lipoprotein receptor (LDLR) could be a co-receptor for PRV infection. Hence, strategies targeting LDLR may provide a promising avenue for the development of effective PRV vaccines and therapeutic interventions.

Modelling pandemic behaviour using an economic multiplayer game

During a pandemic, isolating oneself from the community limits viral transmission and helps avoid repeated societal lockdowns. This entails a social dilemma—either distance oneself from others for the benefit of the public good or free-ride and enjoy the benefits of freedom. It is not yet understood how the unfamiliar incentive structure and interpersonal context presented by a pandemic together modulate individuals’ approach to this social dilemma. In this preregistered study, we take a game-theoretical approach and investigate people’s decisions to self-isolate, using a novel iterated multiplayer game designed to capture the decision-making environment in the pandemic. To elucidate players’ thinking, we use a variation of the strategy method and elicit beliefs about how much others will self-isolate. Players tend to respond to social norms with abidance, rather than transgression; they resist the temptation to freeride when others are self-isolating. However, they deal with exponential growth poorly, as they only self-isolate sufficiently when lockdowns are imminent. Further, increased collective risk can motivate more self-isolation, even though the link between self-isolation and lockdowns is stochastic. Players underreport the influence of others’ choices on their own, and underestimate others’ self-isolation. We discuss implications for public health, and communication to the public.

A Model of Discovery: The Role of Imaging Established and Emerging Non-mammalian Models in Neuroscience

Rodents have been the dominant animal models in neurobiology and neurological disease research over the past 60 years. The prevalent use of rats and mice in neuroscience research has been driven by several key attributes including their organ physiology being more similar to humans, the availability of a broad variety of behavioral tests and genetic tools, and widely accessible reagents. However, despite the many advances in understanding neurobiology that have been achieved using rodent models, there remain key limitations in the questions that can be addressed in these and other mammalian models. In particular, in vivo imaging in mammals at the cell-resolution level remains technically difficult and demands large investments in time and cost. The simpler nervous systems of many non-mammalian models allow for precise mapping of circuits and even the whole brain with impressive subcellular resolution. The types of non-mammalian neuroscience models available spans vertebrates and non-vertebrates, so that an appropriate model for most cell biological questions in neurodegenerative disease likely exists. A push to diversify the models used in neuroscience research could help address current gaps in knowledge, complement existing rodent-based bodies of work, and bring new insight into our understanding of human disease. Moreover, there are inherent aspects of many non-mammalian models such as lifespan and tissue transparency that can make them specifically advantageous for neuroscience studies. Crispr/Cas9 gene editing and decreased cost of genome sequencing combined with advances in optical microscopy enhances the utility of new animal models to address specific questions. This review seeks to synthesize current knowledge of established and emerging non-mammalian model organisms with advances in cellular-resolution in vivo imaging techniques to suggest new approaches to understand neurodegeneration and neurobiological processes. We will summarize current tools and in vivo imaging approaches at the single cell scale that could help lead to increased consideration of non-mammalian models in neuroscience research.

Pseudotyped lentiviral vectors: Ready for translation into targeted cancer gene therapy?

Gene therapy holds great promise for curing cancer by editing the deleterious genes of tumor cells, but the lack of vector systems for efficient delivery of genetic material into specific tumor sites in vivo has limited its full therapeutic potential in cancer gene therapy. Over the past two decades, increasing studies have shown that lentiviral vectors (LVs) modified with different glycoproteins from a donating virus, a process referred to as pseudotyping, have altered tropism and display cell-type specificity in transduction, leading to selective tumor cell killing. This feature of LVs together with their ability to enable high efficient gene delivery in dividing and non-dividing mammalian cells in vivo make them to be attractive tools in future cancer gene therapy. This review is intended to summarize the status quo of some typical pseudotypings of LVs and their applications in basic anti-cancer studies across many malignancies. The opportunities of translating pseudotyped LVs into clinic use in cancer therapy have also been discussed.

Induction of an immortalized songbird cell line allows for gene characterization and knockout by CRISPR-Cas9

The zebra finch is one of the most commonly studied songbirds in biology, particularly in genomics, neuroscience and vocal communication. However, this species lacks a robust cell line for molecular biology research and reagent optimization. We generated a cell line, designated CFS414, from zebra finch embryonic fibroblasts using the SV40 large and small T antigens. This cell line demonstrates an improvement over previous songbird cell lines through continuous and density-independent growth, allowing for indefinite culture and monoclonal line derivation. Cytogenetic, genomic, and transcriptomic profiling established the provenance of this cell line and identified the expression of genes relevant to ongoing songbird research. Using this cell line, we disrupted endogenous gene sequences using S.aureus Cas9 and confirmed a stress-dependent localization response of a song system specialized gene, SAP30L. The utility of CFS414 cells enhances the comprehensive molecular potential of the zebra finch and validates cell immortalization strategies in a songbird species.