Project description:Exposure to environmental teratogenic pollutant leads to severe birth defects. However, the biological events underlying these developmental abnormalities remain undefined. Here we report a molecular link between an environmental stress response pathway and key developmental genes during craniofacial development. In our study, we focused on the development of the facial prominences at E11.5. To do so, we compared the transcriptomes of mutant embryos (*Pax3Pax3-ERD/GFP *called DM in the microarray samples) to the one of control embryos (*Pax3GFP/+ *called GFP in the sample names). These are knock-in genetic models described in Bajard et al., 2006 and Relaix et al., 2005. In both of them a cassette coding for the GFP is replacing one allele of the Pax3 gene. The Pax3-ERD allele is a conditional one that drives the expression of the dominant negative form of Pax3 (Pax3-ERD) composed of the Pax3 DNA binding domain fused to the engrailed repressor domain (ERD) upon activation of a Cre recombinase. In this study, the Cre was driven by the zygote specific PGK enhancer. Strikingly, mutant mice with impaired Pax3/7 function display severe craniofacial defects. We show these are associated with an up-regulation of the signaling pathway mediated by the Aryl hydrocarbon Receptor (AhR), the receptor to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), revealing a genetic interaction between Pax3 and AhR signaling. Activation of AhR signaling in Pax3-deficient embryos drives facial mesenchymal cells out of the cell cycle through the up-regulation of p21 expression. Accordingly, inhibiting AhR activity rescues the cycling status of these cells and the facial closure of Pax3/7 mutants. Together, our findings demonstrate that the regulation of AhR signaling by Pax3/7 is required to protect against TCDD/AhR-mediated teratogenesis during craniofacial development.
Project description:We studied conditional knockout mice in which the vast majority of dentate granule cells (DGCs) fail to develop – including nearly all DGCs in the dorsal hippocampus – secondary to eliminating Wntless (Wls) in a subset of cortical progenitors with Gfap-Cre.
Project description:expression analysis of teratoma, grown from mouse embryonic stem cells that are Evi/Wls knockout cells and comparison with wildtype (control) tumors
Project description:We use scRNA-seq to analyze HSPC and microenvironmental cells in embryonic mouse bone marrow. The embryonic cells are compared with corresponding cells from Bmx-CreER Wls mice. conditional knockout mice, in which artery derived Wnt secretion is blocked.
Project description:Evi/Wls is an essential Wnt secretion factor and important for tissue homeostasis. In the skin Wnt signaling plays an important role in hair follicle formation and maintenance. The aim of the present study is to compare the gene expression profile of Evi/Wls knockout epidermal sheets with wild-type control skin.
Project description:We generated LNP-mRNAs encoding B.1.1.529 SARS-CoV-2 spike, or single transmembrane protein CD22, or GPCR GPRC5D, respectively. Those LNP-mRNAs were intramuscularly administered in a human IgG and IgK knock-in mouse. Single cell VDJ-seq unveiled the sequences of human monoclonal antibodies targeting those target antigens.
Project description:Lipid nanoparticles (LNPs) for mRNA delivery have advanced significantly, but LNP-mediated DNA delivery still faces clinical challenges. This study compared various LNP formulations for delivering DNA-encoded biologics, assessing their expression efficacy and the protective immunity generated by LNP-encapsulated DNA in different models. The LNP formulation used in Moderna’s Spikevax mRNA vaccine (LNP-M) demonstrated a stable nanoparticle structure, high expression efficiency, and low toxicity. Notably, a DNA vaccine encoding the spike protein, delivered via LNP-M, induced stronger antigen-specific antibody and T cell immune responses compared to electroporation. Single-cell RNA sequencing (scRNA-seq) analysis revealed that the LNP-M/pSpike vaccine enhanced CD80 activation signaling in CD8+ T cells, NK cells, macrophages, and DCs, while reducing the immunosuppressive signals. The enrichment of TCR and BCR by LNP-M/pSpike suggested an increase in immune response specificity and diversity. Additionally, LNP-M effectively delivered DNA-encoded antigens, such as mouse PD-L1 and p53R172H, or monoclonal antibodies targeting mouse PD-1 and human p53R282W. This approach inhibited tumor growth or metastasis in several mouse models. The long-term anti-tumor effects of LNP-M-delivered anti-p53R282W antibody relied on memory CD8+ T cell responses and enhanced MHC-I signaling from APCs to CD8+ T cells. These results highlight LNP-M as a promising and effective platform for delivering DNA-based vaccines and cancer immunotherapies.
