Invited Review: Mechanochemical signal transduction in the fetal lung

2000 ◽  
Vol 89 (5) ◽  
pp. 2078-2084 ◽  
Author(s):  
Mingyao Liu ◽  
Martin Post

Growth and maturation of fetal lungs are regulated by both humoral and physical factors. Mechanical stretch stimulates fetal lung cell proliferation and affects fetal lung maturation by influencing the production of extracellular matrix molecules and the expression of specific genes of fetal lung cells. These effects are mediated through special signal transduction pathways in fetal lung cells. Various in vivo and in vitro model systems have been developed to investigate the mechanotransduction process. The diversity and discrepancy of these studies have raised many questions. We will briefly summarize mechanical force-induced signals in fetal lung cell proliferation and differentiation and then discuss several important issues related to these studies.

2004 ◽  
Vol 46 (3) ◽  
pp. 275-282 ◽  
Author(s):  
Sussie Dalvin ◽  
Katsumi Komatsuzaki ◽  
Mark A. Anselmo ◽  
David E. Kling ◽  
Jay J. Schnitzer ◽  
...  

1982 ◽  
Vol 52 (6) ◽  
pp. 1420-1425 ◽  
Author(s):  
I. Gross ◽  
C. M. Wilson

Corticosteroids, thyroid hormones, and theophylline have previously been shown to accelerate fetal lung maturation. We have examined the interactions between these agents in relation to phospholipid synthesis in explants of 18-day fetal rat lung in organ culture. Maximal stimulation of the rate of incorporation of choline into phosphatidylcholine, the most abundant phospholipid in pulmonary surfactant, was observed at a dexamethasone concentration of 100 nM. Exposure to 100 nM dexamethasone, 1.0 mM theophylline, or a combination of the two agents for 48 h resulted, respectively, in 144, 157, and 508% stimulation of the rate of incorporation of choline into disaturated phosphatidylcholine. Similar supra-additive interactions between dexamethasone and dibutyryl adenosine 3′,5′-cyclic monophosphate (cAMP) were observed, but the effects with caffeine were less striking. The increase in the rate of precursor incorporation was associated with a significant increase in the disaturated phosphatidylcholine content of the cultures. Combination of dexamethasone with 100 nM triiodothyronine (the concn producing maximal effects) also resulted in supra-additive stimulation but to a smaller degree. These findings of interactions in vitro suggest that the agents act on the lung at different biochemical sites, but the mechanisms whereby they interact at the cellular level have yet to be established. The data provide a rationale for in vivo animal studies of the effects of combined hormone administration on fetal lung maturation.


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.


Author(s):  
Sharon C.W. Luk ◽  
Sai-ming Ngai ◽  
Stephen K.W. Tsui ◽  
Kwok-pui Fung ◽  
Cheuk-yu Lee ◽  
...  

2021 ◽  
Vol 8 ◽  
Author(s):  
Mandy Laube ◽  
Soeren Pietsch ◽  
Thomas Pannicke ◽  
Ulrich H. Thome ◽  
Claire Fabian

Preterm infants frequently suffer from pulmonary complications due to a physiological and structural lung immaturity resulting in significant morbidity and mortality. Novel in vitro and in vivo models are required to study the underlying mechanisms of late lung maturation and to facilitate the development of new therapeutic strategies. Organoids recapitulate essential aspects of structural organization and possibly organ function, and can be used to model developmental and disease processes. We aimed at generating fetal lung organoids (LOs) and to functionally characterize this in vitro model in comparison to primary lung epithelial cells and lung explants ex vivo. LOs were generated with alveolar and endothelial cells from fetal rat lung tissue, using a Matrigel-gradient and air-liquid-interface culture conditions. Immunocytochemical analysis showed that the LOs consisted of polarized epithelial cell adhesion molecule (EpCAM)-positive cells with the apical membrane compartment facing the organoid lumen. Expression of the alveolar type 2 cell marker, RT2-70, and the Club cell marker, CC-10, were observed. Na+ transporter and surfactant protein mRNA expression were detected in the LOs. First time patch clamp analyses demonstrated the presence of several ion channels with specific electrophysiological properties, comparable to vital lung slices. Furthermore, the responsiveness of LOs to glucocorticoids was demonstrated. Finally, maturation of LOs induced by mesenchymal stem cells confirmed the convenience of the model to test and establish novel therapeutic strategies. The results showed that fetal LOs replicate key biological lung functions essential for lung maturation and therefore constitute a suitable in vitro model system to study lung development and related diseases.


1995 ◽  
Vol 7 (3) ◽  
pp. 443 ◽  
Author(s):  
GC Liggins

Clinical trials of thyrotrophin-releasing hormone (TRH) in conjunction with antepartum glucocorticoid treatment in the prevention of respiratory distress syndrome is based on experimental evidence that fetal lung maturation is accelerated by exposure to raised concentrations of triiodothyronine (T3) in fetal plasma. Studies of fetal rat and rabbit lung in vitro show an inconsistent increase in surfactant synthesis in response to T3 and potentiation of the response to corticosteroid. Experiments with fetal rodents in vivo are difficult to interpret because of confounding effects of the procedures and the responses to T3 are variable. In fetal sheep, very high concentrations of T3 are without effect on lung maturation. These observations suggest that the action of TRH on the lung may be mediated at least in part by one of the numerous, non-hormonal pathways known to be stimulated by TRH, particularly the autonomic nervous system. Experiments in rats and sheep lend support to this possibility. It is concluded that available evidence is inadequate to determine the mechanism of action of TRH.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jia-Huang Liu ◽  
Qi-Fei Wu ◽  
Jun-Ke Fu ◽  
Xiang-Ming Che ◽  
Hai-Jun Li

Obesity could increase the risk of esophageal squamous cell carcinoma (ESCC) and affect its growth and progression, but the mechanical links are unclear. The objective of the study was to explore the impact of obesity on ESCC growth and progression utilizing in vivo trials and cell experiments in vitro. Diet-induced obese and lean nude mice were inoculated with TE-1 cells, then studied for 4 weeks. Serum glucose, insulin, leptin, and visfatin levels were assayed. Sera of nude mice were obtained and then utilized to culture TE-1. MTT, migration and invasion assays, RT-PCR, and Western blotting were used to analyze endocrine effect of obesity on cell proliferation, migration, invasion, and related genes expression of TE-1. Obese nude mice bore larger tumor xenografts than lean animals, and were hyperglycemic and hyperinsulinemic with an elevated level of leptin and visfatin in sera, and also were accompanied by a fatty liver. As for the subcutaneous tumor xenograft model, tumors were more aggressive in obese nude mice than lean animals. Tumor weight correlated positively with mouse body weight, liver weight of mice, serum glucose, HOMA-IR, leptin, and visfatin. Obesity prompted significant TE-1 cell proliferation, migration, and invasion by endocrine mechanisms and impacted target genes. The expression of AMPK and p-AMPK protein decreased significantly ( P < 0.05 ); MMP9, total YAP, p-YAP, and nonphosphorylated YAP protein increased significantly ( P < 0.05 ) in the cells cultured with conditioned media and xenograft tumor from the obese group; the mRNA expression of AMPK decreased significantly ( P < 0.05 ); YAP and MMP9 mRNA expression increased significantly ( P < 0.05 ) in the cells exposed to conditioned media from the obese group. In conclusion, the altered adipokine milieu and metabolites in the context of obesity may promote ESCC growth in vivo; affect proliferation, migration, and invasion of ESCC cells in vitro; and regulate MMP9 and AMPK-YAP signaling pathway through complex effects including the endocrine effect.


2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Jun Liu ◽  
Jipeng Li ◽  
Ke Wang ◽  
Haiming Liu ◽  
Jianyong Sun ◽  
...  

AbstractFork-head box protein M1 (FoxM1) is a transcriptional factor which plays critical roles in cancer development and progression. However, the general regulatory mechanism of FoxM1 is still limited. STMN1 is a microtubule-binding protein which can inhibit the assembly of microtubule dimer or promote depolymerization of microtubules. It was reported as a major responsive factor of paclitaxel resistance for clinical chemotherapy of tumor patients. But the function of abnormally high level of STMN1 and its regulation mechanism in cancer cells remain unclear. In this study, we used public database and tissue microarrays to analyze the expression pattern of FoxM1 and STMN1 and found a strong positive correlation between FoxM1 and STMN1 in multiple types of cancer. Lentivirus-mediated FoxM1/STMN1-knockdown cell lines were established to study the function of FoxM1/STMN1 by performing cell viability assay, plate clone formation assay, soft agar assay in vitro and xenograft mouse model in vivo. Our results showed that FoxM1 promotes cell proliferation by upregulating STMN1. Further ChIP assay showed that FoxM1 upregulates STMN1 in a transcriptional level. Prognostic analysis showed that a high level of FoxM1 and STMN1 is related to poor prognosis in solid tumors. Moreover, a high co-expression of FoxM1 and STMN1 has a more significant correlation with poor prognosis. Our findings suggest that a general FoxM1-STMN1 axis contributes to cell proliferation and tumorigenesis in hepatocellular carcinoma, gastric cancer and colorectal cancer. The combination of FoxM1 and STMN1 can be a more precise biomarker for prognostic prediction.


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