Biology subjects

Cartier, A.

Publications and source records attributed to Cartier, A..

7 recordsLinked to original sources

bioRxiv2026

S1PR1 signaling biases neutrophils toward long-lived low-inflammatory functional states

Sphingosine 1-phosphate (S1P), a lipid mediator that signals through five G protein-coupled S1P receptors (S1PRs), regulates T cell trafficking, tissue residency, and inflammatory processes. In contrast to the established roles of S1P signaling in T cell trafficking, its role in neutrophil biology remains poorly understood. Here, we demonstrate that S1PR1, one of the two S1PRs expressed in neutrophils, promotes mitochondrial fitness, enhances survival, and reduces inflammatory output. Using myeloid- and neutrophil-selective S1PR1 overexpression (S1PR1hi) mouse models, we show that elevated S1PR1 signaling promotes redistribution of neutrophils from the bone marrow to peripheral tissues under steady-state conditions, without inducing overt inflammation or tissue injury. S1PR1hi neutrophils display altered surface marker profiles consistent with a less mature state. These cells also exhibit reduced in vivo turnover, increased mitochondrial membrane potential and oxidative phosphorylation, and transcriptional programs linked to survival and dampened inflammatory signaling. Functionally, S1PR1hi neutrophils exhibit a reduced oxidative burst while preserving phagocytic capacity. However, in vivo bacterial challenge revealed impaired bacterial clearance in the lung. In contrast, in a model of influenza A virus infection of the lung, enhanced neutrophil-intrinsic S1PR1 signaling conferred reduced lung injury, decreased inflammatory output, and improved survival. Together, these findings support a model in which S1PR1 reprograms neutrophils, enabling their survival and dampening inflammatory potential in a context-dependent manner, thereby differentially shaping host defense and tissue protection during microbial infections.

immunology↗

bioRxiv2022

Engineered high-density lipoprotein particles that chaperone bioactive lipid mediators to combat endothelial dysfunction and thromboinflammation

High-density lipoprotein (HDL) particles suppress inflammation-induced tissue injury via vascular and myeloid cell-dependent mechanisms. As such, HDL-associated bioactive lipids such as sphingosine 1-phosphate (S1P) and prostacyclin (PGI2) signal via their respective G protein-coupled receptors on target cells to promote vascular endothelial function and suppress platelet and myeloid-dependent pathophysiology. Here we have constructed a fusion protein of apolipoprotein A1 (ApoA1) and apolipoprotein M (ApoM) (A1M) that forms HDL-like particles and chaperones S1P and Iloprost, stable PGI2 analog. The A1M/S1P complex activates S1P receptor-1 (S1PR1) as a Gi-biased agonist and attenuates the inflammation-induced NF{kappa}B pathway while A1M/Iloprost acts via IP receptor to inhibit platelet aggregation and promote endothelial barrier function. In addition to enhancing the endothelial barrier, A1M/S1P suppresses neutrophil influx, oxidative burst and inflammatory mediator secretion in a sterile inflammation model. We propose that A1M could be useful as a therapeutic to induce S1P and PGI2-dependent anti-inflammatory functions and suppress collateral tissue injury.

biochemistry↗

bioRxiv2021

Multicenter reverse-phase protein array data integration

Among the technologies available for protein biomarker discovery and validation, reverse-phase protein array (RPPA) benefits from unequalled sample throughput. Panels of high-quality antibodies enable the quantification by RPPA of protein abundance and posttranslational modifications in biological specimens with high precision and sensitivity. Incorporation of RPPA technology into clinical and drug development pipelines requires robust assays that generate reproducible results across multiple laboratories. We implemented the first international multicenter pilot study to investigate RPPA workflow variability. We characterized the proteomic responses of a series of breast cancer cells to two cancer drugs. This analysis quantified 86,832 sample spots, representing 108 biological samples, arrayed at three independent RPPA platforms. This unique integrated set of data is publicly available as a resource to the proteomic and cancer research communities to catalyse further analysis and investigation. We anticipate that this dataset will form a reference for the comparison of RPPA workflows and reagents, which can be expanded in the future, and will aid the identification of platform-robust treatment-marker antigens in breast cancer cells. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=95 SRC="FIGDIR/small/458377v1_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@e2fb2forg.highwire.dtl.DTLVardef@1d8f425org.highwire.dtl.DTLVardef@84dd60org.highwire.dtl.DTLVardef@e1ccf7_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2019

Integrative analysis of multi-platform reverse-phase protein array data for the pharmacodynamic assessment of response to targeted therapies

Reverse-phase protein array (RPPA) technology uses panels of high-specificity antibodies to measure proteins and protein post-translational modifications in cells and tissues. The approach offers sensitive and precise quantification of large numbers of samples and has thus found applications in the analysis of clinical and pre-clinical samples. For effective integration into drug development and clinical practice, robust assays with consistent results are essential. Leveraging a collaborative RPPA model, we set out to assess the variability between three different RPPA platforms using distinct instrument set-ups and workflows. Employing multiple RPPA-based approaches operated across distinct laboratories, we characterised a range of human breast cancer cells and their protein-level responses to two clinically relevant cancer drugs. We integrated multi-platform RPPA data and used unsupervised learning to identify protein expression and phosphorylation signatures that were not dependent on RPPA platform and analysis workflow. Our findings indicate that proteomic analyses of cancer cell lines using different RPPA platforms can identify concordant profiles of response to pharmacological inhibition, including when using different antibodies to measure the same target antigens. These results highlight the robustness and the reproducibility of RPPA technology and its capacity to identify protein markers of disease or response to therapy.\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=58 SRC=\"FIGDIR/small/769158v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (19K):\norg.highwire.dtl.DTLVardef@3b72aeorg.highwire.dtl.DTLVardef@e62fe4org.highwire.dtl.DTLVardef@5238c3org.highwire.dtl.DTLVardef@ca925_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2019

Slug/Snail2 is involved in the repression of proliferation genes by TGF-β in bronchial epithelial progenitor cells and is deregulated in abnormal epithelium

Slug/Snail2 belongs to the Epithelial-Mesenchymal Transition (EMT)-inducing transcription factors involved in development and diseases. Slug is expressed in adult stem/progenitor cells of several epithelia, making it unique among these transcription factors. To investigate Slug role in human bronchial epithelium progenitors, we studied primary bronchial basal/progenitor cells in an air-liquid interface culture system that allows regenerating a bronchial epithelium. To identify Slug downstream genes we knocked down Slug in basal/progenitor cells from normal subjects and subjects with COPD, a respiratory disease presenting anomalies in the bronchial epithelium and high levels of TGF-{beta} in the lungs. We show that normal and COPD bronchial basal/progenitors, even when treated with TGF-{beta}, express both epithelial and mesenchymal markers, and that the epithelial marker E-cadherin is not a target of Slug and, moreover, positively correlates with Slug. We reveal that Slug downstream genes responding to both differentiation and TGF-{beta} are different in normal and COPD progenitors, with in particular a set of proliferation-related genes that are among the genes repressed downstream of Slug in normal but not COPD. In COPD progenitors at the onset of differentiation in presence of TGF-{beta}, we show that there is positive correlations between the effect of differentiation and TGF-{beta} on proliferation-related genes and on Slug protein, and that their expression levels are higher than in normal cells. As well, the expression of Smad3 and {beta}-Catenin, two molecules from TGF-{beta} signaling pathways, are higher in COPD progenitors, and our results indicate that proliferation-related genes and Slug protein are increased by different TGF-{beta}-induced mechanisms. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=109 SRC="FIGDIR/small/674127v2_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@524a15org.highwire.dtl.DTLVardef@7dd1e5org.highwire.dtl.DTLVardef@5f3798org.highwire.dtl.DTLVardef@13ae179_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2019

Endothelial sphingosine 1-phosphate receptors promote vascular normalization to influence tumor growth and metastasis

Sphingosine 1-phosphate receptor-1 (S1PR1) is essential for embryonic vascular development and maturation. In the adult, it is a key regulator of vascular barrier function and inflammatory processes. Its roles in tumor angiogenesis, tumor growth and metastasis are not well understood. In this report, we show that S1PR1 is expressed and active in tumor vessels. Tumor vessels that lack S1PR1 (S1pr1 ECKO) show excessive vascular sprouting and branching, decreased barrier function, and poor perfusion accompanied by loose attachment of pericytes. Compound knockout of S1pr1, 2 and 3 genes further exacerbated these phenotypes, suggesting compensatory function of endothelial S1PR2 and 3 in the absence of S1PR1. On the other hand, tumor vessels with high expression of S1PR1 (S1pr1 ECTG) show less branching, tortuosity and enhanced pericyte coverage. Larger tumors and enhanced lung metastasis were seen in S1pr1 ECKO whereas S1pr1 ECTG showed smaller tumors and reduced metastasis. Furthermore, anti-tumor activity of doxorubicin was more effective in S1pr1 ECTG than the wild-type counterparts. These data suggest that tumor endothelial S1PR1 induces vascular normalization and influences tumor growth, evolution and spread. Strategies to enhance S1PR1 signaling in tumor vessels may be an important adjunct to standard cancer therapy.\n\nSignificanceEndothelial sphingosine 1-phosphate receptors modulate tumor angiogenesis by inducing vascular normalization, which allows better blood circulation and enhanced anti-tumor therapeutic efficacy.

cancer biology↗

bioRxiv2018

Heterotypic inter-GPCR β-arrestin coupling regulates lymphatic endothelial junctional architecture in murine lymph nodes

Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) activate G protein-coupled receptors (GPCRs) to regulate key pathobiological processes. Here we report a novel lipid mediator GPCR cross-talk mechanism that modulates lymphatic endothelial junctional architecture in lymph nodes. LPAR1 was identified as an inducer of S1PR1/ {beta}-arrestin coupling from a genome-wide CRISPR/ Cas9 transcriptional activation screen. LPAR1 activation induced S1PR1 {beta}-arrestin recruitment while suppressing Gi protein signaling. Lymphatic endothelial cells from cortical and medullary sinuses of lymph nodes which express LPAR1 and S1PR1, exhibit porous junctional architecture and constitutive S1PR1 coupling to {beta}-arrestin which was suppressed by the LPAR1 antagonist AM095. In endothelial cells, LPAR1-activation increased trans-endothelial permeability and junctional remodeling from zipper-like structures to puncta of adhesion plaques that terminate at actin-rich stress fibers with abundant intercellular gaps. Cross-talk between LPA and S1P receptors regulates complex junctional architecture of lymphatic sinus endothelial cells, a site of high lymphocyte traffic and lymph flow.

cell biology↗