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Biology subjects

Langa-Vives, F.

Publications and source records attributed to Langa-Vives, F..

5 recordsLinked to original sources

ILC3s are Required for Enterocyte Homeostasis to Food Intake

Food provides nutrients that are selectively absorbed by the intestine, but, at the same time, may contain elements that challenge the intestinal barrier and induce post-prandial inflammation (PPI). How PPI is controlled in order to avoid pathological perturbation of homeostasis remains unclear. Here, we report that during fasting, enterocytes increase their absorptive potential and oxidative metabolism, a program that is largely reversed upon food intake of lipids that perturb the intestinal barrier and induce PPI. Such perturbation is countered by ILC3s, in the absence of which PPI increases, program reversal does not occur, and enterocytes engage into excessive oxidative metabolism. This enterocyte state leads to critical hypoglycemia as a consequence of decreased glucose absorption and increased insulinemia, recapitulating the pathological situation found in patients suffering from intestinal damage and sepsis. We hereby uncover a critical function for ILC3s in maintaining enterocyte homeostasis upon challenging food intake.

immunology↗

Nr5a2 is essential for morula development

Early embryogenesis is driven by transcription factors (TFs) that first activate the zygotic genome and then specify the lineages constituting the blastocyst. While the TFs specifying the blastocysts lineages are well characterised, those playing earlier roles are ill-defined. Using mouse models of the TF Nr5a2, we show that Nr5a2-/- embryos arrest at the early morula stage and exhibit overt phenotypical problems such as altered lineage specification, frequent mitotic failure and substantial chromosome segregation defects. Transcriptomic profiling shows that NR5A2 is a master regulator required for appropriate expression of thousands of genes at the 8-cells stage, including lineage-specifying TFs and genes involved in mitosis, telomere maintenance and DNA repair. We conclude that NR5A2 coordinates proliferation, genome stability and lineage specification to ensure proper morula development.

developmental biology↗

Mice Humanized for Major Histocompatibility Complex and Angiotensin-Converting Enzyme 2 with High Permissiveness to SARS-CoV-2 Omicron Replication

Human Angiotensin-Converting Enzyme 2 (hACE2) is the major receptor enabling host cell invasion by SARS-CoV-2 via interaction with Spike glycoprotein. The murine ACE2 ortholog does not interact efficiently with SARS-CoV-2 Spike and therefore the conventional laboratory mouse strains are not permissive to SARS-CoV-2 replication. Here, we generated new hACE2 transgenic mice, which harbor the hACE2 gene under the human keratin 18 promoter, in C57BL/6 "HHD-DR1" background. HHD-DR1 mice are fully devoid of murine Major Histocompatibility Complex (MHC) molecules of class-I and -II and express only MHC molecules from Human Leukocyte Antigen (HLA) HLA 02.01, DRA01.01, DRB1.01.01 alleles, widely expressed in human populations. We selected three transgenic strains, with various hACE2 mRNA expression levels and distinctive profiles of lung and/or brain permissiveness to SARS-CoV-2 replication. Compared to the previously available B6.K18-ACE22Prlmn/JAX mice, which have limited permissiveness to SARS-CoV-2 Omicron replication, these three new hACE2 transgenic strains display higher levels of hACE2 mRNA expression, associated with high permissiveness to the replication of SARS-CoV-2 Omicron sub-variants. As a first application, one of these MHC- and ACE2-humanized strains was successfully used to show the efficacy of a lentiviral vector-based COVID-19 vaccine candidate.

microbiology↗

De novo germline mutation in the Dual Specificity Phosphatase 10 gene accelerates autoimmune diabetes in Non-Obese Diabetic (NOD) mice

Here we report the isolation by selective breeding of two sublines of Non-Obese Diabetic (NOD) mice exhibiting a significant difference in the incidence of autoimmune type 1 diabetes (T1D). Whole genome sequencing of the NOD/NckH (high T1D incidence) and NOD/NckL (low T1D incidence) revealed the presence of a limited number of variants specific to each subline. Treating the age of T1D onset as a quantitative trait and using automated meiotic mapping (AMM), enhanced susceptibility in the NOD/NckH subline was unambiguously attributed to a recessive allele of Dusp10 which encodes a dual specificity phosphatase. The causative effect of the mutation was verified with a high level of confidence by targeting Dusp10 with CRISPR/Cas9 in NOD/NckL mice: in these animals a higher incidence of diabetes was observed. Expression of wild-type Dusp10 correlated with higher levels of surface PD-L1 in the islets of NOD/NckL mice.

immunology↗

Dissection of the Fgf8 regulatory landscape by in vivo CRISPR-editing reveals extensive inter- and intra-enhancer redundancy

Developmental genes are often regulated by multiple elements with overlapping activity. Yet, in most cases, the relative function of those elements and their contribution to endogenous gene expression remain uncharacterized. Illustrating this situation, distinct sets of enhancers have been proposed to direct Fgf8 in the limb apical ectodermal ridge (AER) and the midbrain-hindbrain boundary (MHB). Using in vivo CRISPR/Cas9 genome engineering, we functionally dissect this complex regulatory ensemble and demonstrate two distinct regulatory logics. In the AER, the control of Fgf8 expression appears extremely distributed between different enhancers. In contrast, in the MHB, one of the three active enhancers is essential while the other two are dispensable. Further dissection of the essential MHB enhancer revealed another layer of redundancy and identified two sub-parts required independently for Fgf8 expression and formation of midbrain and cerebellar structures. Interestingly, cross-species transgenic analysis of this enhancer suggests changes of the organisation of this essential regulatory node in the vertebrate lineage.

developmental biology↗