scholarly journals Chorioamnionitis stimulates angiogenesis in saccular stage fetal lungs via CC chemokines

2010 ◽  
Vol 298 (5) ◽  
pp. L637-L645 ◽  
Author(s):  
J. Davin Miller ◽  
John T. Benjamin ◽  
David R. Kelly ◽  
David B. Frank ◽  
Lawrence S. Prince

The fetal lung vasculature forms in tandem with developing airways. Whereas saccular airway morphogenesis is arrested in bronchopulmonary dysplasia (BPD), the potential vascular phenotype in BPD at this stage of development is less well-understood. As inflammation increases the risk of BPD and induces arrest of saccular airway morphogenesis, we tested the effects of Escherichia coli LPS on fetal mouse lung vascular development. Injecting LPS into the amniotic fluid of Tie2- lacZ endothelial reporter mice at embryonic day 15 stimulated angiogenesis in the saccular stage fetal lung mesenchyme. LPS also increased the number of endothelial cells in saccular stage fetal mouse lung explants. Inflammation appeared to directly promote vascular development, as LPS stimulated pulmonary microvascular endothelial cell angiogenesis, cell migration, and proliferation in vitro. Whereas LPS did not increase expression of VEGF, angiopoietin-1 (Ang-1), Tie2, fetal liver kinase-1 (Flk-1), fms-like tyrosine kinase-1 (Flt-1), PDGFA, PDGFB, heparin-binding EGF-like growth factor (HB-EGF), or connective tissue growth factor (CTGF), LPS did stimulate the production of the angiogenic CC chemokines macrophage inflammatory protein-1α (MIP-1α) and monocyte chemoattractant protein-1 (MCP-1). Both MIP-1α and MCP-1 increased angiogenesis in fetal mouse lung explants. In addition, inhibitory antibodies against MIP-1α and MCP-1 blocked the effects of LPS on fetal lung vascular development, suggesting these chemokines are downstream mediators of LPS-induced angiogenesis. We speculate that an inflammation-mediated surge in angiogenesis could lead to formation of aberrant alveolar capillaries in the lungs of patients developing BPD.

1993 ◽  
Vol 265 (3) ◽  
pp. L250-L259
Author(s):  
E. H. Webster ◽  
S. R. Hilfer ◽  
R. L. Searls ◽  
J. Kornilow

The mesodermal capsule of the fetal lung plays a role in differentiation of the respiratory region. It has been proposed for other epithelial organs that the mesodermal capsule influences development by modifying the basal lamina or the extended extracellular matrix. The effect could be on deposition or turnover of collagens, proteoglycans, and/or glycoproteins. This study tests the role of glycoproteins in differentiation of respiratory endings by inhibiting their synthesis with the antibiotic tunicamycin (TM). Lungs at 16 and 18 days gestation and 3 days after birth were cultured with TM and examined for morphological and biochemical differences from normal controls. With TM, alveolar regions did not expand properly and formed fewer type I pneumocytes, although type II pneumocytes were unaffected. The epithelium of untreated respiratory regions showed greater incorporation of radioactive mannose than the airways region or mesenchyme. This incorporation was diminished in TM, but the pattern persisted. Comparison with the results obtained with beta-xyloside suggested that differentiation of type I and type II pneumocytes is under separate control.


2013 ◽  
Vol 304 (6) ◽  
pp. L438-L444 ◽  
Author(s):  
Jennifer J. P. Collins ◽  
Steffen Kunzmann ◽  
Elke Kuypers ◽  
Matthew W. Kemp ◽  
Christian P. Speer ◽  
...  

Inflammation and antenatal glucocorticoids, the latter given to mothers at risk for preterm birth, affect lung development and may contribute to the development of bronchopulmonary dysplasia (BPD). The effects of the combined exposures on inflammation and antenatal glucocorticoids on transforming growth factor (TGF)-β signaling are unknown. TGF-β and its downstream mediators are implicated in the etiology of BPD. Therefore, we asked whether glucocorticoids altered intra-amniotic lipopolysaccharide (LPS) effects on TGF-β expression, its signaling molecule phosphorylated sma and mothers against decapentaplegic homolog 2 (pSmad2), and the downstream mediators connective tissue growth factor (CTGF) and caveolin-1 (Cav-1). Ovine singleton fetuses were randomized to receive either an intra-amniotic injection of LPS and/or maternal betamethasone (BTM) intramuscularly 7 and/or 14 days before delivery at 120 days gestational age (GA; term = 150 days GA). Saline was used for controls. Protein levels of TGF-β1 and -β2 were measured by ELISA. Smad2 phosphorylation was assessed by immunohistochemistry and Western blot. CTGF and Cav-1 mRNA and protein levels were determined by RT-PCR and Western blot. Free TGF-β1 and -β2 and total TGF-β1 levels were unchanged after LPS and/or BTM exposure, although total TGF-β2 increased in animals exposed to BTM 7 days before LPS. pSmad2 immunostaining increased 7 days after LPS exposure although pSmad2 protein expression did not increase. Similarly, CTGF mRNA and protein levels increased 7 days after LPS exposure as Cav-1 mRNA and protein levels decreased. BTM exposure before LPS prevented CTGF induction and Cav-1 downregulation. This study demonstrated that the intrauterine inflammation-induced TGF-β signaling can be inhibited by antenatal glucocorticoids in fetal lungs.


2020 ◽  
Vol 64 (3) ◽  
pp. 155-164
Author(s):  
Kelly L Short ◽  
A Daniel Bird ◽  
Bennet K L Seow ◽  
Judy Ng ◽  
Annie R A McDougall ◽  
...  

Glucocorticoid (GC) signaling via the glucocorticoid receptor (GR) is essential for lung maturation in mammals. Previous studies using global or conditional mouse model knockouts of the GR gene have established that GR-mediated signaling in the interstitial mesenchyme of the fetal lung is critical for normal lung development. Screens for downstream GC-targets in conditional mesenchymal GR deficient mouse lung (GRmesKO) identified Versican (Vcan), an important extracellular matrix component and cell proliferation regulator, as a potential GR-regulated target. We show that, of the five major VCAN isoforms, the VCAN-V1 isoform containing the GAGβ domain is the predominant VCAN isoform in the fetal mouse lung distal mesenchyme at both E16.5 and E18.5, whereas the GAGα-specific VCAN-V2 isoform was only localized to the smooth muscle surrounding proximal airways. Both Vcan-V1 mRNA and protein levels were strongly overexpressed in the GRmesKO lung at E18.5. Finally, we investigated the GC regulation of the ECM protease ADAMTS 12 and showed that Adamts 12 mRNA levels were markedly reduced at E18.5 in GRmesKO fetal mouse lung and were strongly induced by both cortisol and betamethasone in cultures of primary rat fetal lung fibroblasts. ADAMTS12 protein immunoreactivity was also strongly increased in the distal lung at E18.5, after dexamethasone treatment in utero. In summary, glucocorticoid signaling via GR represses GAGβ domain-containing VCAN isoforms in distal lung mesenchyme in vivo by repressing Vcan gene expression and, in part, by inducing the ECM protease ADAMTS12, thereby contributing to the control of ECM remodelling and lung cell proliferation prior to birth.


2020 ◽  
Author(s):  
Sohyun Moon ◽  
Sangmi Lee ◽  
JoyAnn Caesar ◽  
Sarah Pruchenko ◽  
Andew Leask ◽  
...  

ABSTRACTConnective tissue growth factor (CTGF) or CCN2 is a matricellular protein essential for normal embryonic development and tissue repair. CTGF exhibits cell- and context-dependent activities, but the CTGF function in vascular development and permeability barrier is not known. Here we show that endothelial cells (ECs) are one of the major cellular sources of CTGF in the developing and adult retinal vasculature. Mice lacking CTGF expression either globally or specifically in ECs exhibit impaired vascular cell growth and morphogenesis, and blood barrier breakdown. The global molecular signature of CTGF includes cytoskeletal and extracellular matrix protein, growth factor, and transcriptional co-regulator genes such as yes-associated protein (YAP). YAP, itself a transcriptional activator of the CTGF gene, mediates several CTGF-controlled angiogenic and barriergenic transcriptional programs. Re-expression of YAP rescues, at least partially, angiogenesis and barriergenesis in CTGF mutant mouse retinas. Thus, the CTGF-YAP angiomodulatory pathway is critical for vascular development and barrier function.


2004 ◽  
Vol 287 (5) ◽  
pp. L999-L1006 ◽  
Author(s):  
Lawrence S. Prince ◽  
Victor O. Okoh ◽  
Thomas O. Moninger ◽  
Sadis Matalon

Chorioamnionitis is a major cause of preterm delivery. Infants exposed to inflammation in utero and then born preterm may have improved lung function in the immediate postnatal period. We developed a mouse model of chorioamnionitis to study the inflammatory signaling mechanisms that might influence fetal lung maturation. With this in vivo model, we found that Escherichia coli lipopolysaccharide (LPS) increased the number of alveolar type II cells in the fetal mouse lung. LPS also increased type II cell number in cultured fetal lung explants, suggesting that LPS could directly signal the fetal lung in the absence of maternal influences. Using immunostaining, we localized cells within the fetal mouse lung expressing the LPS receptor molecule Toll-like receptor 4 (TLR4). Similar to the signaling pathways in inflammatory cells, LPS activated NF-κB in fetal lung explants. Activation of the TLR4/NF-κB pathway appeared to be required, as LPS did not increase the number of type II cells in C.C3H- Tlr4 Lps-d mice, a congenic strain containing a loss of function mutation in tlr4. In addition, the sesquiterpene lactone parthenolide inhibited NF-κB activation following LPS exposure and blocked the LPS-induced increase in type II cells. On the basis of these data from our mouse model of chorioamnionitis, it appears that LPS specifically activated the TLR4/NF-κB pathway, leading to increased type II cell maturation. These data implicate an important signaling mechanism in chorioamnionitis and suggest the TLR4/NF-κB pathway can influence lung development.


Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1784
Author(s):  
Lisa Kurmann ◽  
Michal Okoniewski ◽  
Raghvendra K. Dubey

Many pathological conditions of the brain are associated with structural abnormalities within the neurovascular system and linked to pericyte (PC) loss and/or dysfunction. Since crosstalk between endothelial cells (ECs) and PCs greatly impacts the function of the blood–brain barrier (BBB), effects of PCs on endothelial integrity and function have been investigated extensively. However, the impact of ECs on the function and activity of PCs remains largely unknown. Hence, using co-cultures of human brain vascular PCs with human cerebral microvascular ECs on opposite sides of porous Transwell inserts which facilitates direct EC–PC contact and improves EC barrier function, we analyzed EC-driven transcriptomic changes in PCs using microarrays and changes in cytokines/chemokines using proteome arrays. Gene expression analysis (GEA) in PCs co-cultured with ECs versus PCs cultured alone showed significant upregulation of 1′334 genes and downregulation of 964 genes. GEA in co-cultured PCs revealed increased expression of five prominent PC markers as well as soluble factors, such as transforming growth factor beta, fibroblast growth factor, angiopoietin 1, brain-derived neurotrophic factor, all of which are involved in EC–PC crosstalk and BBB induction. Pathway enrichment analysis of modulated genes showed a strong impact on many inflammatory and extracellular matrix (ECM) pathways including interferon and interleukin signaling, TGF-β and interleukin-1 regulation of ECM, as well as on the mRNA processing pathway. Interestingly, while co-culture induced the mRNA expression of many chemokines and cytokines, including several CCL- and CXC-motif ligands and interleukins, we observed a decreased expression of the same inflammatory mediators on the protein level. Importantly, in PCs, ECs significantly induced interferon associated proteins (IFIT1, IFI44L, IF127, IFIT3, IFI6, IFI44) with anti-viral actions; downregulated prostaglandin E receptor 2 (prevent COX-2 mediated BBB damage); upregulated fibulin-3 and connective tissue growth factor essential for BBB integrity; and multiple ECMs (collagens and integrins) that inhibit cell migration. Our findings suggest that via direct contact, ECs prime PCs to induce molecules to promote BBB integrity and cell survival during infection and inflammatory insult. Taken together, we provide first evidence that interaction with ECs though porous membranes induces major changes in the transcriptomic and proteomic profile of PCs. ECs influence genes involved in diverse aspects of PC function including PC maturation, cell survival, anti-viral defense, blood flow regulation, immuno-modulation and ECM deposition.


2007 ◽  
Vol 292 (1) ◽  
pp. L223-L231 ◽  
Author(s):  
Steffen Kunzmann ◽  
Christian P. Speer ◽  
Alan H. Jobe ◽  
Boris W. Kramer

Chorioamnionitis is frequently associated with preterm birth and increases the risk of adverse outcomes such as bronchopulmonary dysplasia (BPD). Transforming growth factor (TGF)-β1 is a key regulator of lung development, airway remodeling, lung fibrosis, and regulation of inflammation, and all these processes contribute to the development of BPD. Connective tissue growth factor (CTGF) is a downstream mediator of some of the profibrotic effects of TGF-β1, vascular remodeling, and angiogenesis. TGF-β1-induced CTGF expression can be blocked by TNF-α. We asked whether chorioamnionitis-associated antenatal inflammation would regulate TGF-β1, the TGF-β1 signaling pathway, and CTGF in preterm lamb lungs. Fetal sheep were exposed to 4 mg of intra-amniotic endotoxin or saline for 5 h, 24 h, 72 h, or 7 days before preterm delivery at 125 days gestation (full term = 150 days). Intra-amniotic endotoxin increased lung TGF-β1 mRNA and protein expression. Elevated TGF-β1 levels were associated with TGF-β1-induced phosphorylation of Smad2. CTGF was selectively expressed in lung endothelial cells in control lungs, and intra-amniotic endotoxin caused CTGF expression to decrease to 30% of control values and TNF-α protein to increase. The antenatal inflammation-induced TGF-β1 expression and Smad signaling in the fetal lamb lung may contribute to impaired lung alveolarization and reduced lung inflammation. Decreased CTGF expression may inhibit vascular development or remodeling and limit lung fibrosis during remodeling. These effects may contribute to the impaired alveolar and pulmonary vascular development that is the hallmark of the new form of BPD.


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