Biology subjects

VILGRAIN, I.

Publications and source records attributed to VILGRAIN, I..

3 recordsLinked to original sources

bioRxiv2025

Glycation enhances protein association with lipid bilayer membranes

Glycation is a non-enzymatic post-translational modification that leads to the formation of advanced glycation end-products (AGEs), which accumulate in the blood-stream under chronic hyperglycemia and are implicated in diabetes-related pathologies. While glycated proteins such as albumin or hemoglobin are widely used as biomarkers for glycemic control, the structural and chemical changes induced by glycation may also alter their interactions with lipid interfaces, including cellular membranes and lipoproteins, potentially affecting their biological distribution and diagnostic detectability. In this study, we investigated how glycation influences the interaction of bovine serum albumin (BSA) with supported lipid bilayers (SLBs) of different compositions, used as model systems to replicate the diversity of membrane surface charges and fluidity. Using neutron reflectometry (NR), we compared the membrane association of BSA and a chemically-enhanced glycated form of BSA (gBSA), focusing on nanostructural changes at the bilayer interface. Our results showed negligible interaction of either proteins with zwitterionic or cationic membranes. In contrast, both BSA and gBSA exhibited significant binding to negatively charged bilayers, with glycation significantly amplifying this interaction. Quantitatively, the membrane-associated protein volume fraction increased from 0.11 (BSA) to 0.17 (gBSA), suggesting that glycation modifies the proteins surface properties in ways that promote stronger lipid interactions with negatively charged membranes. These findings suggest that glycation not only affects protein structure but also modulates protein-membrane affinity in a lipid-dependent manner. This has important implications for the bioavailability and behavior of glycated albumin in the bloodstream, potentially influencing the accuracy of clinical assays and contributing to membrane-related pathophysiology in diabetes. Our work highlights the need for a deeper understanding of glycation-induced changes in protein-lipid interactions and their consequences for biomarker reliability and disease mechanisms. Graphical TOC Entry O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/685514v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@150e71aorg.highwire.dtl.DTLVardef@749b35org.highwire.dtl.DTLVardef@179f468org.highwire.dtl.DTLVardef@19cfe8e_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2024

Efficient fine-tuning of endothelial gene expression by Y to Phe mutation in the VE-cadherin gene

Cancer and inflammation are associated with vascular diseases that affect endothelial cells (ECs) and alter gene expression. We aimed at understanding whether the site Y685 in the cytoplasmic domain of VE-cadherin triggers epigenetic programming in vivo. Using our knock-in mice carrying the Y685F VE-cadherin mutation, RNA sequencing from lung ECs identified 884 differentially expressed genes (DEG) involved in processes such as cell-cell adhesion, vascular development, and angiogenesis. The 30 DEGs include 22 down-regulated genes (genes encoding cell signalling enzymes, anion transport and lipid metabolism) and 8 up-regulated genes, including the endothelial-specific S1PR1. Analysis of the VEGF/VEGFR2 signaling pathway shows a significant decrease in the expression of pY1173VEGFR2 whereas VEGF remains constant, this was consistent with impaired migration, proliferation and protrusive properties of ECs in vitro. Co-immunoprecipitation experiments showed that c-Src and Y685F-VE-cadherin association which was enhanced in KI compared to WT, resulting in increased in Y685F-VE-cadherin phosphorylation at site Y731. As a consequence, its partner {beta}-catenin translocates to the nucleus. CHIPS assay showed that FOXF1 binds to the s1pr1 promoter, leading to increased expression of the S1PR1. In vivo, in the lung vasculature, this process was associated with increased vessel wall thickness and reduced fibrosis. Overall, our findings provide a novel transcriptomic profile triggered by Y685F-VE-cadherin ECs for potential insights into therapeutic targets to envisage normalisation of the tumor vasculature.

cell biology↗

bioRxiv2023

Single tyrosine mutation in VE-cadherin modulates gene lung expressions: evidence for FOXF1 mediated S1PR1 upregulation to stabilize vessels in mice

RationalePhosphorylation-dephosphorylation are processes involved in the adhesion of endothelial cells (ECs) to maintain vascular integrity in adults. VE-cadherin is a target for Src-mediated Y685 phosphorylation, identified in highly vascularized human glioblastoma where it is involved in the abnormal feature of tumor blood vessels. ObjectiveWe aimed at understanding the molecular mechanisms through which Y685F-VE-cadherin triggers S1PR1 gene expression and stabilizes lung vessels in adult mice. Methods and ResultsWe compared lung ECs from a knock-in (KI) mouse carrying a point mutation in VE-cadherin (Tyr 685 to Phe) to Wild type. Analysis of EC parameters showed a difference in the migratory rate was between ECs from KI (22.45% {+/-} 5.207) and WT (13.24% {+/-} 5.17) (p-value=0.034). The direct adhesion of ECs from KI mice to fibronectin was significantly higher (37.625 {+/-} 9.23) than that of the WT (26.8 {+/-} 3.258, p-value=0.012). In the fibrin bead assay, ECs from KI showed a weaker angiogenic response. The transcriptome of mutated ECs showed that 884 genes were dysregulated of which 766 genes were downregulated and 118 genes were upregulated. The Gene Ontology Enrichment showed that most of the genes were related to cell-cell adhesion and angiogenesis. Focusing on angiogenic genes, we found that Sphingosine-1-phosphate-receptor was a gene upregulated in mutated ECs which was confirmed by RT-PCR and westernblotting. Mechanistically, chromatin immunoprecipitation assay (CHIPS) demonstrated that FOXF1 directly bound to the S1pr1 promoter 7 fold greater than WT. As a consequence, VE-cadherin at the membrane was higher in the mutant vs WT (100 {+/-} 6.52 for WT vs 189.7 {+/-} 21.06 for KI (p-value 0.0001). Finally, lung morphometric analysis showed less vessels and vascular remodeling with no fibrosis in mutated mice. ConclusionsThese data extend our knowledge on pY-VE-cadherin mediated pathological angiogenesis and provide new therapeutic opportunities to vascular normalization through pharmacological inhibition of the Y685-VE-cadherin phosphorylation.

cell biology↗