Lung Fibroblasts Improve Differentiation of Rat Type II Cells in Primary Culture

Shannon, John M.; Pan, Tianli; Nielsen, Larry D.; Edeen, Karen E.; Mason, Robert J.

doi:10.1165/ajrcmb.24.3.4302

Cited by 66 publications

(59 citation statements)

References 30 publications

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“…Investigations in mesenchyme-free cultures have evidenced the prominent role of factors of the fibroblast growth factor family, namely FGF-1 and FGF-7 (KGF), in these processes (30). These paracrine mechanisms that play a crucial role during development (6, 7) appear to be maintained throughout life (32). A possible interpretation of the previously evidenced effects of VEGF on fetal lung explants (5) or on mouse lung in vivo (8) is a stimulation of mesenchymal and/or endothelial cells by VEGF to produce mediators that would, in turn, exert stimulating effects on alveolar type II cell proliferation and maturation.…”

Section: Discussionmentioning

confidence: 99%

Effects of vascular endothelial growth factor on isolated fetal alveolar type II cells

Raoul¹,

Chailley‐Heu²,

Barlier-Mur³

et al. 2004

American Journal of Physiology-Lung Cellular and Molecular Phys

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Previous investigations gained from in vivo or lung explant studies suggested that VEGF is an autocrine proliferation and maturation factor for developing alveolar type II cells. The objective of this work was to determine whether VEGF exerted its growth and maturation effects directly on isolated type II cells. These were isolated from 19-day fetal rat lung and cultured in defined medium. The presence of VEGF receptor-2 was assessed in cultured cells at the pre- and posttranslational levels. Recombinant VEGF165, formerly found to be active on lung explants, failed to enhance type II cell proliferation estimated by thymidine and 5-bromo-2′-deoxy-uridine incorporation. It increased choline incorporation in saturated phosphatidylcholine by 27% but did not increase phospholipid surfactant pool size. VEGF (100 ng/ml) left unchanged the transcript level of surfactant proteins (SP)-A, SP-C, and SP-D but increased SP-B transcripts to four times the control steady-state level. VEGF slightly retarded, but did not prevent, the in vitro transdifferentiation of type II into type I cells, as assessed by immunolabeling of the type I cell marker T1α. We conclude that, with the exception of SP-B expression, which appears to be controlled directly, the previously observed effects of this VEGF isoform on type II cells are likely to be exerted indirectly through reciprocal paracrine interactions involving other lung cell types.

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Section: Discussionmentioning

confidence: 99%

Effects of vascular endothelial growth factor on isolated fetal alveolar type II cells

Raoul¹,

Chailley‐Heu²,

Barlier-Mur³

et al. 2004

American Journal of Physiology-Lung Cellular and Molecular Phys

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“…Total cellular RNA was isolated by ultracentrifugation for 18 h at 150,000 g through a 5.7 M CsCl cushion. Total RNA isolated from type II cells was analyzed for surfactant protein mRNA expression with a ribonuclease protection assay (RPA) that allowed simultaneous measurement of mRNAs for SP-A, -B, -C, and -D as described previously (46,54). The primers used to generate the riboprobes and their sizes have been reported (54).…”

Section: Methodsmentioning

confidence: 99%

“…In this report, we use the term "differentiation" to mean the expression and secretion of the surfactant proteins and not the transdifferentiation of type II cells into type I cells. Previous studies (9,12,43,46) indicate that maintenance of type II cell differentiation is best achieved with a permissive substratum and a combination of differentiation factors and/or coculture with fibroblasts. The substratum on which the type II cells are cultured is critically important.…”

mentioning

confidence: 99%

“…Keratinocyte growth factor (KGF), fibroblast growth factor (FGF)-7, and acidic FGF (FGF-1) increase expression of surfactant proteins A, B, and D (SP-A, SP-B, and SP-D, respectively) (46,48,52). Both SP-A and SP-D are increased in lavage fluid of rats instilled with KGF (54).…”

mentioning

confidence: 99%

“…Both SP-A and SP-D are increased in lavage fluid of rats instilled with KGF (54). Corticosteroids are especially stimulatory for the expression of SP-B but may be inhibitory for SP-A and SP-C (2,46). The type of serum in which the cells are maintained also alters type II cell phenotype.…”

mentioning

confidence: 99%

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Maintenance of surfactant protein A and D secretion by rat alveolar type II cells in vitro

Mason

Lewis

Edeen

et al. 2002

American Journal of Physiology-Lung Cellular and Molecular Phys

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Secretion of surfactant proteins A and D (SP-A and SP-D) has been difficult to study in vitro because a culture system for maintaining surfactant secretion has been difficult to establish. We evaluated several growth factors, corticosteroids, rat serum, and a fibroblast feeder layer for the ability to produce and maintain a polarized epithelium of type II cells that secretes SP-A and SP-D into the apical medium. Type II cells were plated on a filter insert coated with an extracellular matrix and were cultured at an air-liquid interface. Keratinocyte growth factor (KGF) stimulated type II cell proliferation and secretion of SP-A and SP-D more than fibroblast growth factor-10 (FGF-10), hepatocyte growth factor (HGF), or heparin-binding epidermal-like growth factor (HB-EGF). Cells cultured in the presence of KGF and rat serum with or without fibroblasts had high surfactant protein mRNA levels and exhibited a high level of SP-A and SP-D secretion. Dexamethasone inhibited type II cell proliferation but increased expression of SP-B. In the presence of KGF, rat serum, and dexamethasone, the mRNAs for the surfactant proteins were maintained at high levels. Secretion of SP-A and SP-D was found to be independent of phospholipid secretion.

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Rosiglitazone, a peroxisome proliferator-activated receptor-γ agonist, prevents hyperoxia-induced neonatal rat lung injury in vivo

et al. 2006

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Molecular disruption of homeostatic alveolar epithelial-mesenchymal interactions results in transdifferentiation of alveolar interstitial lipofibroblasts to myofibroblasts. Although this process was suggested to be a central molecular event in the pathogenesis of bronchopulmonary dysplasia (BPD), so far it has been only demonstrated in vitro; whether it also occurs in vivo is unknown. Our objectives were to determine if exposure to hyperoxia results in pulmonary alveolar lipo-to-myofibroblast transdifferentiation in vivo, and whether treatment with a potent peroxisome proliferator-activated receptor gamma (PPARgamma) (the key lipogenic fibroblast nuclear transcription factor) agonist, rosiglitazone, prevents this process. Newborn Sprague Dawley rat pups were exposed to control (21% O2), hyperoxia alone (95% O2 for 24 hr), or hyperoxia with rosiglitazone (95% O2 for 24 hr + rosiglitazone, 3 mg/kg, administered intraperitoneally) conditions. Subsequently, pups were sacrificed, and lung tissue was analyzed by morphometry, and by reverse transcription-polymerase chain reaction, Western hybridization, and immunohistochemistry for the expression of key lipogenic and myogenic markers. We observed a significant decrease in the expression of lipogenic markers, and a significant increase in the expression of myogenic markers in the hyperoxia-alone group. These hyperoxia-induced morphologic, molecular, and immunohistochemical changes were almost completely prevented by rosiglitazone. This is the first evidence of in vivo lipo-to-myofibroblast transdifferentiation and its almost complete prevention by rosiglitazone, prompting us to conclude that administration of PPARgamma agonists may be a novel, effective strategy to prevent the hyperoxia-induced lung molecular injury that has been implicated in the pathogenesis of BPD.

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Lung Fibroblasts Improve Differentiation of Rat Type II Cells in Primary Culture

Cited by 66 publications

References 30 publications

Effects of vascular endothelial growth factor on isolated fetal alveolar type II cells

Effects of vascular endothelial growth factor on isolated fetal alveolar type II cells

Maintenance of surfactant protein A and D secretion by rat alveolar type II cells in vitro

Rosiglitazone, a peroxisome proliferator-activated receptor-γ agonist, prevents hyperoxia-induced neonatal rat lung injury in vivo

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