Biology subjects

Lujan, V.

Publications and source records attributed to Lujan, V..

3 recordsLinked to original sources

bioRxiv2024

A hidden mark of a troubled past: neuroimaging and transcriptomic analyses reveal interactive effects of maternal immune activation and adolescent THC exposure in the absence of overt behavioural disruptions

Maternal exposure to infections during gestation has been shown to predispose individuals to the development of schizophrenia. Additionally, clinical data suggest that cannabis use could trigger the onset of schizophrenia in vulnerable individuals. However, the direction of causality remains unclear. To elucidate this issue, we utilised a rat model of maternal immune activation, combined with exposure to increasing doses of THC during adolescence, in both male and female rats. We investigated several behaviours in adulthood that resemble specific symptoms of schizophrenia, including impairments in working memory, deficits in sensorimotor gating, alterations in social behaviour, anhedonia, and potential changes in implicit learning (conditioned taste aversion). Furthermore, we conducted a longitudinal positron emission tomography (PET) study to identify affected brain regions and subsequently collected brain samples from one of these regions (the orbitofrontal cortex) for RNA sequencing analyses. These analyses were also performed on peripheral blood mononuclear cells to identify peripheral biomarkers. Notably, while no overt behavioural disruptions were observed, our PET scans revealed several brain alterations dependent on the combination of both exposures. Additionally, the transcriptomic studies demonstrated that maternal immune activation affected glutamatergic and serotoninergic genes, with the combination of both exposures shifting the expression from down-regulation to up-regulation. In peripheral cells, interactive effects were observed on inflammatory pathways, and some genes were proposed as biomarkers of the disease. These results suggest that the combination of these two vulnerability factors leaves a lasting mark on the body, potentially predisposing individuals to the disease even before behavioural alterations manifest.

neuroscience↗

bioRxiv2024

Computationally designed mRNA-launched protein nanoparticle vaccines

Both protein nanoparticle and mRNA vaccines were clinically de-risked during the COVID-19 pandemic1-6. These vaccine modalities have complementary strengths: antigen display on protein nanoparticles can enhance the magnitude, quality, and durability of antibody responses7-10, while mRNA vaccines can be rapidly manufactured11 and elicit antigen-specific CD4 and CD8 T cells12,13. Here we leverage a computationally designed icosahedral protein nanoparticle that was redesigned for optimal secretion from eukaryotic cells14 to develop an mRNA-launched nanoparticle vaccine for SARS-CoV-2. The nanoparticle, which displays 60 copies of a stabilized variant of the Wuhan-Hu-1 Spike receptor binding domain (RBD)15, formed monodisperse, antigenically intact assemblies upon secretion from transfected cells. An mRNA vaccine encoding the secreted RBD nanoparticle elicited 5- to 28-fold higher levels of neutralizing antibodies than an mRNA vaccine encoding membrane-anchored Spike, induced higher levels of CD8 T cells than the same immunogen when delivered as an adjuvanted protein nanoparticle, and protected mice from vaccine-matched and -mismatched SARS-CoV-2 challenge. Our data establish that delivering protein nanoparticle immunogens via mRNA vaccines can combine the benefits of each modality and, more broadly, highlight the utility of computational protein design in genetic immunization strategies.

immunology↗

bioRxiv2023

Integrated Organ Immunity: Antigen-specific CD4-T cell-derived IFN-γ induced by BCG imprints prolonged lung innate resistance against respiratory viruses

Bacille Calmette-Guerin (BCG) vaccination can confer non-specific protection against heterologous pathogens. However, the underlying mechanisms remain mysterious. Here, we show that mice immunized intravenously with BCG exhibited reduced weight loss and/or improved viral clearance when challenged with SARS-CoV-2 and influenza. Protection was first evident between 14 - 21 days post vaccination, and lasted for at least 42 days. Remarkably, BCG induced a biphasic innate response in the lung, initially at day 1 and a subsequent prolonged phase starting at [~]15 days post vaccination, and robust antigen-specific Th1 responses. MyD88-dependent TLR signaling was essential for the induction of the innate and Th1 responses, and protection against SARS-CoV-2. Depletion of CD4+ T cells or IFN-{gamma} activity prior to infection obliterated innate activation and protection. Single cell and spatial transcriptomics revealed CD4-dependent expression of interferon-stimulated genes (ISGs) in myeloid, type II alveolar and lung epithelial cells. Thus, BCG elicits "integrated organ immunity" where CD4+ T cells act on local myeloid and epithelial cells to imprint prolonged antiviral innate resistance.

immunology↗