Mesenchymal determination of mechanical strain-induced fetal lung cell proliferation

1998 ◽  
Vol 275 (3) ◽  
pp. L545-L550 ◽  
Author(s):  
Jing Xu ◽  
Mingyao Liu ◽  
A. Keith Tanswell ◽  
Martin Post
Keyword(s):  
Epithelial Cells ◽  
Dna Synthesis ◽  
Lung Development ◽  
Mechanical Strain ◽  
Fetal Lung ◽  
Cell Types ◽  
Fetal Lung Development ◽  
Fetal Rat ◽  
Fetal Rat Lung ◽  
Fetal Breathing Movements

Fetal breathing movements play an important role in normal fetal lung growth. We have previously shown that an intermittent mechanical strain regimen (60 cycles/min, 15 min/h), simulating normal fetal breathing movements, stimulated growth of mixed fetal rat lung cells in organotypic culture. In the present study, we examined the individual responses of the two major fetal lung cell types, fibroblasts and epithelial cells, to mechanical strain. Also, we investigated the effect of mesenchymal-epithelial interactions on strain-induced cell proliferation during fetal lung development. Fibroblasts and epithelial cells from day 18to day 21 fetal rat lung (term = 22 days), cultured alone or as various recombinants, were subjected to either a 48-h static culture or to strain, and DNA synthesis was measured. Both cell types responded individually to strain with enhanced DNA synthesis throughout late fetal lung development. Independent of the recombination ratio, there was no additive response to strain when fibroblasts and epithelial cells from the same gestation were recombined. In contrast, strain-induced DNA synthesis was suppressed when cells from different gestations were recombined. The ontogenic response pattern of recombinants to mechanical strain was similar to that of fibroblasts but not of epithelial cells. Strain-induced proliferation increased and peaked at the early canalicular stage of lung development at 19 days of gestation and declined thereafter. We conclude that strain-enhanced growth of the fetal lung is gestation dependent and that the gestational response to mechanical force is regulated by the mesenchyme.

Sex hormones regulate CFTR in developing fetal rat lung epithelial cells

1997 ◽  
Vol 272 (5) ◽  
pp. L844-L851 ◽  
Author(s):  
N. B. Sweezey ◽  
F. Ghibu ◽  
S. Gagnon
Keyword(s):  
Epithelial Cells ◽  
Sex Hormones ◽  
Functional Activity ◽  
Lung Development ◽  
Fetal Lung ◽  
Lung Epithelial Cells ◽  
Rat Lung ◽  
Fetal Rat ◽  
Lung Epithelial ◽  
Fetal Rat Lung

Sex hormones modulate two normal processes of late-gestation mammalian lung development: the onset of augmented production of surfactant phospholipids and the loss of mesenchymal cells. As prenatal lung development advances, epithelial chloride secretory pathways diminish as opposing sodium absorptive pathways increase in expression. We hypothesized that sex hormones may influence both the gene expression and functional activity of the chloride channel known as the cystic fibrosis transmembrane conductance regulator (CFTR) in fetal lung epithelium. We report here that sex hormones exert opposite effects on CFTR. Androgen increases and estrogen decreases CFTR functional activity [as assessed by CFTR antisense (but not sense) oligodeoxynucleotide-sensitive adenosine 3',5'-cyclic monophosphate-stimulated cell volume reduction or by glibenclamide-sensitive, amiloride-insensitive transepithelial electrical potential] in primary cultures of fetal rat lung epithelial cells. No alterations in CFTR mRNA levels measured by quantitative polymerase chain reaction amplification of reverse transcripts) accompanied either the changes in functional activity induced by sex hormones or the changes observed during normal development, suggesting that sex hormone modulation of CFTR in antenatal lung occurs at a posttranscriptional level. Our data are consistent with the hypothesis that both androgen and estrogen contribute to the male disadvantage with respect to fetal lung functional development.

scholarly journals A role for caveolin-1 in mechanotransduction of fetal type II epithelial cells

2010 ◽  
Vol 298 (6) ◽  
pp. L775-L783 ◽  
Author(s):  
Yulian Wang ◽  
Benjamin S. Maciejewski ◽  
Diana Drouillard ◽  
Melissa Santos ◽  
Michael A. Hokenson ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Epithelial Cells ◽  
Lung Development ◽  
Fetal Lung ◽  
Mechanical Stretch ◽  
Erk Pathway ◽  
Type Ii ◽  
Caveolin 1 ◽  
Fetal Lung Development ◽  
Type Ii Cell

Mechanical forces are critical for fetal lung development. Using surfactant protein C (SP-C) as a marker, we previously showed that stretch-induced fetal type II cell differentiation is mediated via the ERK pathway. Caveolin-1, a major component of the plasma membrane microdomains, is important as a signaling protein in blood vessels exposed to shear stress. Its potential role in mechanotransduction during fetal lung development is unknown. Caveolin-1 is a marker of type I epithelial cell phenotype. In this study, using immunocytochemistry, Western blotting, and immunogold electron microscopy, we first demonstrated the presence of caveolin-1 in embryonic day 19 (E19) rat fetal type II epithelial cells. By detergent-free purification of lipid raft-rich membrane fractions and fluorescence immunocytochemistry, we found that mechanical stretch translocates caveolin-1 from the plasma membrane to the cytoplasm. Disruption of the lipid rafts with cholesterol-chelating agents further increased stretch-induced ERK activation and SP-C gene expression compared with stretch samples without disruptors. Similar results were obtained when caveolin-1 gene was knocked down by small interference RNA. In contrast, adenovirus overexpression of the wild-type caveolin-1 or delivery of caveolin-1 scaffolding domain peptide inside the cells decreased stretch-induced ERK phosphorylation and SP-C mRNA expression. In conclusion, our data suggest that caveolin-1 is present in E19 fetal type II epithelial cells. Caveolin-1 is translocated from the plasma membrane to the cytoplasm by mechanical stretch and functions as an inhibitory protein in stretch-induced type II cell differentiation via the ERK pathway.

Mechanical strain induces constitutive and regulated secretion of glycosaminoglycans and proteoglycans in fetal lung cells

1996 ◽  
Vol 109 (6) ◽  
pp. 1605-1613
Author(s):  
J. Xu ◽  
M. Liu ◽  
J. Liu ◽  
I. Caniggia ◽  
M. Post
Keyword(s):  
Calcium Influx ◽  
Mechanical Strain ◽  
Fetal Lung ◽  
Lung Cells ◽  
Regulatory Pathway ◽  
Regulated Secretion ◽  
Fetal Rat ◽  
Fetal Rat Lung ◽  
Constitutive Secretion ◽  
The Individual

We have previously shown that an intermittent strain regimen, which simulates fetal breathing movements, enhanced mixed fetal rat lung cell proliferation in organotypic culture. As glycosaminoglycans (GAGs) and proteoglycans (PGs) may modulate growth factor activities, we investigated the effect of intermittent strain on the formation and secretion of GAGs and PGs. Mechanical strain increased the incorporation of [3H]glucosamine and 35SO4 into GAGs and promoted the release of GAGs into the medium. The composition of the individual GAG molecules was not altered by strain. Mixed fetal lung cells subjected to strain secreted more [35S]biglycan into the medium than static controls but biglycan mRNA expression was not significantly altered. As mechanical strain primarily affected the secretion of GAGs and PGs, we then investigated which secretory pathways were stimulated by strain. Fetal lung cells secreted GAGs mainly through a constitutive (basal) pathway which was stimulated by strain. In contrast to static cultures, strain-induced constitutive secretion was partially blocked by the cytoskeletal disruptors colchicine and cytochalasin B, but not by the small G-protein inhibitors N-acetyl-S-farnesyl-L-cysteine and perillic acid. This result suggests that strain-induced constitutive export of GAGs depends on the functional integrity of the cytoskeleton. Strain also triggered the regulated secretion of GAGs. The strain-induced regulatory pathway in fetal lung cells was blocked by ionomycin, BAPTA/AM and gadolinium, suggesting that strain stimulated the regulatory pathway by inducing a rapid calcium influx via a stretch-activated ion channel. We conclude that mechanical strain of mixed fetal lung cells stimulates GAG and PG exocytosis via activation of both the regulated and constitutive pathways.

Growth and developmental regulation of wnt-2 (irp) gene in mesenchymal cells of fetal lung

1992 ◽  
Vol 262 (6) ◽  
pp. L672-L683 ◽  
Author(s):  
B. K. Levay-Young ◽  
M. Navre
Keyword(s):  
Lung Development ◽  
Developmental Regulation ◽  
Fetal Lung ◽  
Fibroblast Cell ◽  
Mrna Levels ◽  
Rat Lung ◽  
Intercellular Interaction ◽  
Wnt Proteins ◽  
Fetal Rat ◽  
Fetal Rat Lung

The wnt gene family encodes a group of proteins implicated as intercellular signaling molecules in vertebrate development. Because many wnt genes are also expressed in the lung, we have examined whether the wnt family member wnt-2 (irp) plays a role in lung development. We have cloned rat wnt-2 and found that this cDNA detects multiple mRNAs expressed at high levels in fetal rat lung. Much lower levels were found in adult rat lung and other tissues, including, surprisingly, the mammary gland. The wnt-2 mRNA was also detected in human fetal lung fibroblast cell lines, where the mRNA levels were dramatically regulated by growth state as well as growth factor stimulation. In situ hybridization showed that, in fetal rat lung, wnt-2 mRNA expression is restricted to the mesenchyme; levels in the developing epithelium were indistinguishable from background. Based on the known properties of other wnt proteins, our data lead us to propose that wnt-2 may play a role in lung development by mediating intercellular interaction(s) between mesenchyme and epithelium.

scholarly journals N-Methyl-D-aspartate Receptor Excessive Activation Inhibited Fetal Rat Lung DevelopmentIn VivoandIn Vitro

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Zhengchang Liao ◽  
Xiaocheng Zhou ◽  
Ziqiang Luo ◽  
Huiyi Huo ◽  
Mingjie Wang ◽  
...  
Keyword(s):  
Lung Development ◽  
Fetal Lung ◽  
Lung Weight ◽  
Mk 801 ◽  
Fetal Lung Development ◽  
Fetal Rat ◽  
Intrauterine Hypoxia ◽  
Excessive Activation

Background. Intrauterine hypoxia is a common cause of fetal growth and lung development restriction. Although N-methyl-D-aspartate receptors (NMDARs) are distributed in the postnatal lung and play a role in lung injury, little is known about NMDAR’s expression and role in fetal lung development.Methods. Real-time PCR and western blotting analysis were performed to detect NMDARs between embryonic days (E) 15.5 and E21.5 in fetal rat lungs. NMDAR antagonist MK-801’s influence on intrauterine hypoxia-induced retardation of fetal lung development was testedin vivo, and NMDA’s direct effect on fetal lung development was observed using fetal lung organ culturein vitro.Results. All seven NMDARs are expressed in fetal rat lungs. Intrauterine hypoxia upregulated NMDARs expression in fetal lungs and decreased fetal body weight, lung weight, lung-weight-to-body-weight ratio, and radial alveolar count, whereas MK-801 alleviated this damagein vivo.In vitroexperiments showed that NMDA decreased saccular circumference and area per unit and downregulated thyroid transcription factor-1 and surfactant protein-C mRNA expression.Conclusions. The excessive activation of NMDARs contributed to hypoxia-induced fetal lung development retardation and appropriate blockade of NMDAR might be a novel therapeutic strategy for minimizing the negative outcomes of prenatal hypoxia on lung development.

The adenylate cyclase response to parathyroid hormone in fetal lung fibroblasts is enhanced by cortisol

1987 ◽  
Vol 7 (6) ◽  
pp. 503-508 ◽  
Author(s):  
Carolyn Lowe ◽  
Peter M. Barling ◽  
Stephen J. M. Skinner
Keyword(s):  
Parathyroid Hormone ◽  
Epithelial Cells ◽  
Adenylate Cyclase ◽  
Fetal Lung ◽  
Lung Fibroblasts ◽  
Rat Lung ◽  
Osteosarcoma Cells ◽  
Fetal Rat ◽  
Fetal Rat Lung ◽  
Umr 106

Parathyroid hormone (PTH, <10−8 M) stimulated adenylate cyclase in fibroblasts, but not epithelial cells, isolated from fetal rat lung. In contrast to osteosarcoma cells (UMR 106), the response of fibroblasts to PTH was increased by pretreatment with cortisol (< 10−8-10−7 M).

Expression of TGF-alpha, EGF, and EGF receptor in fetal rat lung

1994 ◽  
Vol 267 (4) ◽  
pp. L384-L389 ◽  
Author(s):  
T. P. Strandjord ◽  
J. G. Clark ◽  
D. K. Madtes
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Lung Development ◽  
Egf Receptor ◽  
Late Gestation ◽  
Rat Lung ◽  
Cultured Fibroblasts ◽  
Receptor Mrna ◽  
Fetal Rat ◽  
Fetal Rat Lung

To define the distribution of transforming growth factor-alpha (TGF-alpha) and its relationship to epidermal growth factor (EGF) and EGF receptor in lung development and to determine whether epithelial cells produce TGF-alpha, we studied the expression of TGF-alpha, EGF, and their receptor in late-gestation fetal rat lung and in cultured fetal rat lung cells. TGF-alpha, EGF, and EGF receptor were colocalized in epithelial and smooth muscle cells of bronchioles and bronchi and in epithelial cells of saccules. Epithelial cells cultured from late-gestation fetal rat lung transcribe TGF-alpha and EGF receptor mRNA and produce TGF-alpha and EGF receptor proteins. Cultured fibroblasts contained EGF receptor mRNA, but no detectable TGF-alpha mRNA. These results demonstrate fetal lung epithelial cells are a source for TGF-alpha and suggest that TGF-alpha might act through an autocrine or paracrine mechanism with epithelial and mesenchymal cells. The colocalization of TGF-alpha and EGF suggests that these growth factors might act in parallel in lung development.

Antisense oligonucleotides for PDGF-B and its receptor inhibit mechanical strain-induced fetal lung cell growth

1995 ◽  
Vol 269 (2) ◽  
pp. L178-L184 ◽  
Author(s):  
M. Liu ◽  
J. Liu ◽  
S. Buch ◽  
A. K. Tanswell ◽  
M. Post
Keyword(s):  
Cell Growth ◽  
Dna Synthesis ◽  
Kinase Inhibitor ◽  
Mechanical Strain ◽  
Fetal Lung ◽  
Lung Cells ◽  
Mrna Levels ◽  
Signaling Mechanism ◽  
Fetal Breathing ◽  
Fetal Breathing Movements

An intermittent mechanical strain regimen, which simulates fetal breathing movements, has been shown to enhance DNA synthesis and cell division of fetal rat lung cells. The signaling mechanism through which the physical stimulus is transduced is unknown. Herein, we report that mechanical strain (5% elongation, 60 cycles/min) of fetal lung cells, cultured in a three-dimensional environment provided by Gelfoam sponges, increased the mRNA levels of platelet-derived growth factor B (PDGF-B) and beta-receptor (PDGF-beta-R) within 5 min of the onset of strain. Both PDGF-BB and PDGF-beta-R proteins were increased after a 24-h intermittent strain (15 min/h). Phosphorothioate antisense PDGF-B oligonucleotides (ON) at 15 microM abolished the strain-enhanced DNA synthesis and cell growth. Scrambled PDGF-B ON had no such effect. A neutralizing PDGF-BB antibody (10 micrograms/ml) also attenuated strain-induced DNA synthesis. Furthermore, the strain-induced stimulatory effect on DNA synthesis of fetal lung cells was blocked by tyrphostin 9 (1 microM), a PDGF receptor-associated tyrosine kinase inhibitor, but not by its inactive structural analogue tyrphostin 1. Antisense but not sense PDGF-beta-R ON (10 microM) also abrogated the strain-enhanced DNA synthesis. These results suggest that physical forces such as fetal breathing movements regulate fetal lung cell growth by controlling PDGF-B and PDGF-beta-R gene expression.

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