ABSTRACT
Neutrophils (PMNs) reside as a marginated pool within the vasculature, ready for deployment during infection. However, how endothelial cells (ECs) control PMN extravasation and activation to strengthen tissue homeostasis remains ill-defined. Here, we found that the vascular ETS-related gene (ERG) is a generalized mechanism regulating PMN activity in preclinical tissue injury models and human patients. We show that ERG loss in ECs rewired PMN-transcriptome, enriched for genes associated with the CXCR2-CXCR4 signaling. Rewired PMNs compromise mice survival after pneumonia and induced lung vascular inflammatory injury following adoptive transfer into naïve mice, indicating their longevity and inflammatory activity memory. Mechanistically, EC-ERG restricted PMN extravasation and activation by upregulating the deubiquitinase A20 and downregulating the NFκB-IL8 cascade. Rescuing A20 in EC-Erg -/- endothelium or suppressing PMN-CXCR2 signaling rescued EC control of PMN activation. Findings deepen our understanding of EC control of PMN-mediated inflammation, offering potential avenues for targeting various inflammatory diseases. Highlights: ERG regulates trans-endothelial neutrophil (PMN) extravasation, retention, and activationLoss of endothelial (EC) ERG rewires PMN-transcriptomeAdopted transfer of rewired PMNs causes inflammation in a naïve mouse ERG transcribes A20 and suppresses CXCR2 function to inactivate PMNs. In brief/blurb: The authors investigated how vascular endothelial cells (EC) control polymorphonuclear neutrophil (PMN) extravasation, retention, and activation to strengthen tissue homeostasis. They showed that EC-ERG controls PMN transcriptome into an anti-adhesive and anti-inflammatory lineage by synthesizing A20 and suppressing PMNs-CXCR2 signaling, defining EC-ERG as a target for preventing neutrophilic inflammatory injury.
ABSTRACT
Cell surface G protein-coupled receptors (GPCRs), upon agonist binding, undergo serine-threonine phosphorylation, leading to either receptor recycling or degradation. Here, we show a new fate of GPCRs, exemplified by ER retention of sphingosine-1-phosphate receptor 1 (S1PR1). We show that S1P phosphorylates S1PR1 on tyrosine residue Y143, which is associated with recruitment of activated BiP from the ER into the cytosol. BiP then interacts with endocytosed Y143-S1PR1 and delivers it into the ER. In contrast to WT-S1PR1, which is recycled and stabilizes the endothelial barrier, phosphomimicking S1PR1 (Y143D-S1PR1) is retained by BiP in the ER and increases cytosolic Ca2+ and disrupts barrier function. Intriguingly, a proinflammatory, but non-GPCR agonist, TNF-α, also triggered barrier-disruptive signaling by promoting S1PR1 phosphorylation on Y143 and its import into ER via BiP. BiP depletion restored Y143D-S1PR1 expression on the endothelial cell surface and rescued canonical receptor functions. Findings identify Y143-phosphorylated S1PR1 as a potential target for prevention of endothelial barrier breakdown under inflammatory conditions.
Subject(s)
Endoplasmic Reticulum/genetics , Inflammation/genetics , Sphingosine-1-Phosphate Receptors/genetics , Tumor Necrosis Factor-alpha/genetics , Cytosol/metabolism , Endocytosis/genetics , Endoplasmic Reticulum Chaperone BiP/chemistry , Endoplasmic Reticulum Chaperone BiP/genetics , Endothelial Cells/metabolism , Humans , Inflammation/pathology , Phosphorylation/genetics , Proteolysis , Receptors, G-Protein-Coupled/genetics , Sphingosine-1-Phosphate Receptors/metabolism , Tyrosine/geneticsABSTRACT
[Figure: see text].
Subject(s)
Acute Lung Injury/metabolism , Cell Proliferation , Endothelial Cells/metabolism , Endotoxemia/metabolism , Lung/blood supply , Lysophospholipids/metabolism , Regeneration , Sphingosine-1-Phosphate Receptors/metabolism , Sphingosine/analogs & derivatives , Acute Lung Injury/genetics , Acute Lung Injury/pathology , Animals , Anion Transport Proteins/genetics , Anion Transport Proteins/metabolism , Capillary Permeability , Cell Lineage , Cells, Cultured , Disease Models, Animal , Endothelial Cells/pathology , Endotoxemia/genetics , Endotoxemia/pathology , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Humans , Mice, Knockout , Phenotype , Phosphotransferases (Alcohol Group Acceptor)/genetics , Phosphotransferases (Alcohol Group Acceptor)/metabolism , STAT3 Transcription Factor/genetics , STAT3 Transcription Factor/metabolism , Signal Transduction , Sphingosine/metabolism , Sphingosine-1-Phosphate Receptors/geneticsABSTRACT
We have recently uncovered that endothelial cell (EC) S1PR1 controls the effectiveness of VEGFR2 driven tumor angiogenesis. By using tumor ECs, EC-S1PR1-/- mice and S1PR1 antagonist, we showed that VEGF-VEGFR2 pathway requires EC-S1PR1-induced signaling to efficiently drive tumor vascularization and growth, indicating combining S1PR1 antagonist with anti-VEGF/VEGFR2 therapy may eradicate resistant tumors.
ABSTRACT
The vascular endothelial growth factor-A (VEGF-A)-VEGFR2 pathway drives tumor vascularization by activating proangiogenic signaling in endothelial cells (ECs). Here, we show that EC-sphingosine-1-phosphate receptor 1 (S1PR1) amplifies VEGFR2-mediated angiogenic signaling to enhance tumor growth. We show that cancer cells induce S1PR1 activity in ECs, and thereby, conditional deletion of S1PR1 in ECs (EC-S1pr1-/- mice) impairs tumor vascularization and growth. Mechanistically, we show that S1PR1 engages the heterotrimeric G-protein Gi, which amplifies VEGF-VEGFR2 signaling due to an increase in the activity of the tyrosine kinase c-Abl1. c-Abl1, by phosphorylating VEGFR2 at tyrosine-951, prolongs VEGFR2 retention on the plasmalemma to sustain Rac1 activity and EC migration. Thus, S1PR1 or VEGFR2 antagonists, alone or in combination, reverse the tumor growth in control mice to the level seen in EC-S1pr1-/- mice. Our findings suggest that blocking S1PR1 activity in ECs has the potential to suppress tumor growth by preventing amplification of VEGF-VEGFR2 signaling.
