Vegeto, E. | bioRxiv Science

bioRxiv2026

Spatiotemporal atlas of pro-inflammatory (NF-kB) and anti-inflammatory (STAT6) signalling using reporter mice during mRNA vaccination

The immunization process unfolds through a precisely orchestrated sequence of innate and adaptive events across distinct anatomical sites. Although many mechanisms underlying vaccination are well described, most vaccines have been developed empirically, partly due to the lack of tools enabling rapid, organ-specific analysis of immune activation. To address this gap, we developed and validated a novel STAT6 reporter mouse enabling dynamic in vivo whole-body imaging and ex vivo analysis of STAT6-mediated anti-inflammatory signalling, and combined it with an established NF-{kappa}B reporter model to dissect immune activation induced by two LNP-encapsulated mRNA vaccines encoding the same antigen but differing in RNA chemistry (unmodified versus N{superscript 1}-methyl-pseudouridine (m{superscript 1}{Psi})-modified). This dual-reporter system enabled the creation of a spatiotemporal atlas of vaccine-induced signalling, revealing chemistry-dependent immune dynamics and identifying the liver as a predominant early hub for both NF-{kappa}B and STAT6 activity following systemic administration. Integration with antibody measurements demonstrated that early STAT6 activation followed by rapid signal resolution--rather than prolonged NF-{kappa}B-mediated inflammation--correlated with robust humoral responses, suggesting that monitoring NF-{kappa}B and STAT6 dynamics could provide predictive insight into vaccine immunogenicity. Together, these findings establish NF-{kappa}B and STAT6 reporter mice as rapid in vivo screening tools for the early assessment of vaccine immunogenicity and performance. By enabling dynamic, organ-resolved immune profiling, this approach paves the way for more rational, mechanism-driven design of mRNA vaccines and underscores the importance of further investigating the effects of vaccines on the liver, both as a primary LNP target and as an immunologically tolerogenic organ.

immunology↗

bioRxiv2021

Inhibition of microglial GBA hampers the microglia-mediated anti-oxidant and protective response in neurons

Homozygotic mutations in the GBA gene cause Gauchers disease, moreover, both patients and heterozygotic carriers have been associated with 20- to 30-fold increased risk of developing Parkinsons disease. In homozygosis, these mutations impair the activity of {beta}-glucocerebrosidase, the enzyme encoded by GBA, and generate a lysosomal disorder in macrophages, which changes morphology towards an engorged phenotype, considered the hallmark of Gauchers disease. In the brain, most of the pathological effects caused by GBA mutations have been attributed to the {beta}-glucocerebrosidase deficit in neurons, while a microglial phenotype for these mutations has never been reported. Here, we applied the bioluminescence imaging technology, immunohistochemical and gene expression analysis to investigate the consequences of microglial {beta}-glucocerebrosidase inhibition in the brain of reporter mice, in primary neuron/microglia co-cultures and in cell lines. Our data demonstrate the existence of a novel mechanism by which microglia sustain the antioxidant/detoxifying response mediated by the nuclear factor erythroid 2-related factor 2 in neurons. The central role played by microglia in this neuronal response in vivo was proven by pharmacological depletion of the lineage in the brain, while co-cultures experiments provided insight on the nature of this cell-to-cell communication showing that this mechanism requires a direct microglia-to-neuron contact supported by functional actin structures. Pharmacological inhibition of microglial {beta}-glucocerebrosidase was proven to induce morphological changes, turn on an anti-inflammatory/repairing pathway and hinder the microglia ability to activate the anti-oxidant/detoxifying response, thus increasing the neuronal susceptibility to neurotoxins. Altogether, our data suggest that microglial {beta}-glucocerebrosidase inhibition impairs microglia-to-neuron communication increasing the sensitivity of neurons to oxidative or toxic insults, thus providing a possible mechanism for the increased risk of neurodegeneration observed in carriers of GBA mutations. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=154 SRC="FIGDIR/small/427380v1_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@15c2c3corg.highwire.dtl.DTLVardef@5c4e34org.highwire.dtl.DTLVardef@12718dorg.highwire.dtl.DTLVardef@dcfeca_HPS_FORMAT_FIGEXP M_FIG C_FIG In BriefMicroglia, through actin-dependent structures, contact neurons and induce a detoxification response by increasing the NFE2L2 signalling pathway. Inhibition of GCase activity by CBE treatment produces a morpho-functional change in microglia cells hampering the neuroprotective microglia-neuron communication thus inducing a phenotype in dopaminergic neurons characterized by increased susceptibility to oxidative stress or toxic insults.

neuroscience↗