Abstract
Systemic sepsis is a known risk factor for bronchopulmonary dysplasia (BPD) in premature infants, a disease characterized by dysregulated angiogenesis and impaired vascular and alveolar development. We have previoulsy reported that systemic endotoxin dysregulates pulmonary angiogenesis resulting in alveolar simplification mimicking BPD in neonatal mice, but the underlying mechanisms remain unclear. We undertook an unbiased discovery approach to identify novel signaling pathways programming sepsis-induced deviant lung angiogenesis. Pulmonary endothelial cells (EC) were isolated for RNA-Seq from newborn C57BL/6 mice treated with intraperitoneal lipopolysaccharide (LPS) to mimic systemic sepsis. LPS significantly differentially-regulated 269 genes after 6 h, and 1,934 genes after 24 h. Using bioinformatics, we linked 6 h genes previously unknown to be modulated by LPS to 24 h genes known to regulate angiogenesis/vasculogenesis to identify pathways programming deviant angiogenesis. An immortalized primary human lung EC (HPMEC-im) line was generated by SV40 transduction to facilitate mechanistic studies. RT-PCR and transcription factor binding analysis identified FOSL1 (FOS like 1) as a transcriptional regulator of LPS-induced downstream angiogenic or vasculogenic genes. Over-expression and silencing studies of FOSL1 in immortalized and primary HPMEC demonstrated that baseline and LPS-induced expression of ADAM8, CXCR2, HPX, LRG1, PROK2, and RNF213 was regulated by FOSL1. FOSL1 silencing impaired LPS-induced in vitro HPMEC angiogenesis. In conclusion, we identified FOSL1 as a novel regulator of sepsis-induced deviant angiogenic signaling in mouse lung EC and human fetal HPMEC.
Highlights
Bronchopulmonary dysplasia (BPD) is a developmental lung disorder characterized by simplified alveoli and dysmorphic pulmonary v asculature[1,2,3,4,5,6]
To identify novel targets induced by systemic endotoxin, mouse lung endothelial cell (EC) were isolated from 4-day old (DOL-4) LPS-treated (2 mg/kg intraperitoneal, i.p) and control littermates (n = 3/group) after 6 h, and RNA-Seq was performed
We examined the impact of FOSL1 in regulating angiogenic sprouting in primary Human primary pulmonary microvascular endothelial cells (HPMEC) by pursuing a matrigel-based angiogenesis assay in HPMEC
Summary
Bronchopulmonary dysplasia (BPD) is a developmental lung disorder characterized by simplified alveoli and dysmorphic pulmonary v asculature[1,2,3,4,5,6]. Recent studies have found that maternal chorioamnionitis increases the incidence of BPD and perinatal m ortality[8], and postnatal sepsis or pneumonia increases the risk of preterm infants developing BPD9. The objective of this study was to identify novel pathways by which systemic sepsis programs aberrant angiogenesis in the developing lung using an unbiased approach involving RNA-Seq and bioinformatics methods. By combining discovery-based RNA sequencing studies in a neonatal mouse model of sterile sepsis complemented by validation strategies using genetic manipulation in primary fetal human lung endothelial cell (EC) and an immortalized lung EC line we developed, we identify the transcription factor FOSL1 (FOS like 1, known as FRA-1, FOS-related antigen 1), as a novel regulator of endotoxin-mediated dysangiogenesis in the developing lung
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
