Programming of neutrophil transcriptome by endothelial ERG maintains anti-inflammatory vascular niche in the lungs

Neutrophils, the predominant blood leukocyte and first responders to the infection, reside as the marginated pool in the lungs. Vascular hyperpermeability and activation of infiltrating neutrophils is the hallmark of lethal acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). However, signaling nodes that govern crosstalk among these ontologically distinct cell types to maintain tissue homeostasis remain unclear. Here, we identify the ERG transcription factor, which maintains endothelial cell (EC) lineage, as the instructor of anti-inflammatory neutrophils. We show that ERG is highly expressed in lung EC, but the expression was reduced markedly during neutrophilic injury by bacterial pneumonia. Intravital imaging and FACS analysis of mice lungs conditionally lacking ERG in the endothelium (iEC-ERG −/− mice) showed increased neutrophil retention and activation due to rewiring of their transcriptome (hereafter referred to as EC-ERG null neutrophils). RNA sequencing of EC-ERG null neutrophils showed genes enriched with inflammation (IL-1β, TNF-α, MIP-2α), survival (RelB, CD47), and retention (CXCR4) markers. Neutrophils isolated from the blood of ARDS patients similarly showed increased expression of IL-8, TNF-α, and CXCR4 expression. EC-ERG null neutrophils induced lung injury when adoptively transferred into a naïve mouse. EC-ERG loss elicited an immune migratory and chemotactic program by activating the NF-κB-IL8 cascade, exacerbating ALI in a mouse model. We show that ERG in endothelium preserves neutrophil activation and infiltration by upregulating the multipurpose deubiquitinase A20 expression in mouse and human lung endothelial cells (EC). Rescuing A20 deubiquitinase or suppressing IL8-CXCR2 axis through small molecule inhibitor, Reparixin, reversed hyperpermeability, and neutrophilic injury. In summary, our study identifies specialized ERG-instructed anti-inflammatory ‘immune niche’ to prevent neutrophilic inflammation and lung injury. National Institutes of Health (NIH) Grants HL060678, HL084153. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.