transforming-growth-factor-beta and Bronchopulmonary-Dysplasia

As survival of extremely preterm infants continues to improve, there is also an associated increase in bronchopulmonary dysplasia (BPD), one of the most significant complications of preterm birth. BPD development is multifactorial resulting from exposure to multiple antenatal and postnatal stressors. BPD has both short-term health implications and long-term sequelae including increased respiratory, cardiovascular, and neurological morbidity. Transforming growth factor β (TGF-β) is an important signaling pathway in lung development, organ injury, and fibrosis and is implicated in the development of BPD. This review provides a detailed account on the role of TGF-β in antenatal and postnatal lung development, the effect of known risk factors for BPD on the TGF-β signaling pathway, and how medications currently in use or under development, for the prevention or treatment of BPD, affect TGF-β signaling.

Topics: Bronchopulmonary Dysplasia; Female; Humans; Infant; Infant, Newborn; Infant, Premature; Lung; Pregnancy; Premature Birth; Signal Transduction; Transforming Growth Factor beta

The transforming growth factor (TGF)-beta superfamily of secreted growth factors consists of more than 40 members, including the TGF-beta isoforms themselves, bone morphogenetic proteins, and activins. Most of these factors have been shown to be essential for proper organ development, a process often recapitulated in chronic diseases. Importantly, TGF-beta superfamily members are key regulators of extracellular matrix composition and alveolar epithelial cell and fibroblast function in the lung. Both during lung development and disease, TGF-betas therefore control lung homeostasis by providing the structural requirements and functional micromilieu needed for physiological epithelial cell function and proper gas exchange. Prolonged alterations of TGF-beta signaling have been shown to result in structural changes in the lung that compromise gas exchange and lung function, as seen in arrested lung development, a feature of bronchopulmonary dysplasia, lung fibrosis, and chronic obstructive pulmonary disease. All these syndromes share a loss of functional alveolar structures, which ultimately leads to a decreased life expectancy. In this review, we cover our current understanding of the impact of TGF-beta signaling on chronic lung disease. We focus on distorted TGF-beta signaling in bronchopulmonary dysplasia and chronic obstructive pulmonary disease as prototype diseases of the premature and matured lung, respectively, which are both characterized by functional and structural loss of alveolar units.

Topics: Bronchopulmonary Dysplasia; Emphysema; Humans; Infant, Newborn; Pulmonary Alveoli; Pulmonary Disease, Chronic Obstructive; Signal Transduction; Transforming Growth Factor beta

Various pre- and postnatal risk factors, which act additively or synergistically induce an injurious inflammatory response in the airways and the pulmonary interstitium of preterm infants with bronchopulmonary dysplasia. This inflammatory response is characterized by an accumulation of neutrophils and macrophages as well as an arsenal of proinflammatory mediators that affect the endothelium and alveolar-capillary integrity. Besides proinflammatory cytokines and toxic oxygen radicals, lipid mediators as well as potent proteases may be responsible for acute lung injury. There is increasing evidence that an imbalance between pro- and anti-inflammatory factors, which should protect the alveoli and lung tissue, are key features in the pathogenesis of bronchopulmonary dysplasia. In addition, a subnormal generation of growth factors may affect alveolarization and vascular development in preterm infants with bronchopulmonary dysplasia. In this condensed review article, the current concepts on the possible role of inflammation in the evolution of bronchopulmonary dysplasia will be summarized.

Topics: Blood-Air Barrier; Bronchopulmonary Dysplasia; Chemotaxis; Chorioamnionitis; Cytokines; Endothelium; Female; Humans; Hyperoxia; Infant, Newborn; Infant, Premature; Inflammation Mediators; Intercellular Signaling Peptides and Proteins; Macrophages; Neutrophils; Oxygen; Peptide Hydrolases; Pneumonia; Pregnancy; Pulmonary Alveoli; Respiration, Artificial; Transforming Growth Factor beta

Topics: Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Disease Models, Animal; Epidermal Growth Factor; Fibroblast Growth Factors; Growth Substances; Humans; Infant, Newborn; Lung; Platelet-Derived Growth Factor; Respiratory Distress Syndrome, Newborn; Somatomedins; Transforming Growth Factor alpha; Transforming Growth Factor beta; Vascular Endothelial Growth Factor A

Pulmonary inflammation is a key feature in the pathogenesis of bronchopulmonary dysplasia (BPD). This inflammatory process, induced by multiple risk factors, is characterized by the presence of inflammatory cells, cytokines and an arsenal of additional humoral mediators in the airways and pulmonary tissue of preterm infants with the condition. Several mediators have a direct detrimental effect on pulmonary structures by affecting cell integrity and inducing apoptosis. An imbalance between pro-inflammatory and anti-inflammatory factors can generally be considered to be a hallmark of lung injury. Intrauterine exposure to pro-inflammatory cytokines or antenatal infection may prime the fetal lung such that minimally injurious postnatal events provoke an excessive pulmonary inflammatory response that most certainly affects normal alveolization and pulmonary vascular development in preterm infants with BPD.

Topics: Animals; Bronchopulmonary Dysplasia; Chorioamnionitis; Cytokines; Female; Humans; Infant, Newborn; Inflammation; Leukocyte Elastase; Models, Immunological; Pregnancy; Respiration, Artificial; Risk Factors; Transforming Growth Factor beta

We compared serial measurements of inflammatory mediators and markers in infants treated with inhaled nitric oxide or placebo to assess the effects of inhaled nitric oxide therapy on lung inflammation during bronchopulmonary dysplasia. We investigated relationships between respiratory severity scores and airway concentrations of inflammatory markers/mediators.. As part of the Nitric Oxide (to Prevent) Chronic Lung Disease trial, a subset of 99 infants (52 placebo-treated infants and 47 inhaled nitric oxide-treated infants; well matched at baseline) had tracheal aspirate fluid collected at baseline, at 2 to 4 days, and then weekly while still intubated during study gas treatment (minimum of 24 days). Fluid was assessed for interleukin-1beta, interleukin-8, transforming growth factor-beta, N-acetylglucosaminidase, 8-epi-prostaglandin F2alpha, and hyaluronan. Results were normalized to total protein and secretory component of immunoglobulin A.. At baseline, there was substantial variability of each measured substance and no correlation between tracheal aspirate fluid levels of any substance and respiratory severity scores. Inhaled nitric oxide administration did not result in any time-matched significant change for any of the analytes, compared with the placebo-treated group. There was no correlation between any of the measured markers/mediators and respiratory severity scores throughout the 24 days of study gas administration. In the posthoc analysis of data for inhaled nitric oxide-treated infants, there was a difference at baseline in 8-epi-prostaglandin F2alpha levels for infants who did (n = 21) and did not (n = 26) develop bronchopulmonary dysplasia at postmenstrual age of 36 weeks.. Inhaled nitric oxide, as administered in this study, seemed to be safe. Its use was not associated with any increase in airway inflammatory substances.

Topics: Administration, Inhalation; Biomarkers; Bronchopulmonary Dysplasia; Cytokines; Dinoprost; Double-Blind Method; Female; Humans; Infant, Newborn; Infant, Premature; Inflammation Mediators; Interleukin-1beta; Interleukin-8; Male; Nitric Oxide; Prognosis; Reference Values; Reproducibility of Results; Respiration, Artificial; Sensitivity and Specificity; Trachea; Transforming Growth Factor beta; Treatment Outcome

It is well known that supplemental oxygen used to treat preterm infants in respiratory distress is associated with permanently disrupting lung development and the host response to influenza A virus (IAV). However, many infants who go home with normally functioning lungs are also at risk for hyperreactivity after a respiratory viral infection. We recently reported a new, low-dose hyperoxia mouse model (40% for 8 days; 40×8) that causes a transient change in lung function that resolves, rendering 40×8 adult animals functionally indistinguishable from room air controls. Here we report that when infected with IAV, 40×8 mice display an early transient activation of TGFβ signaling and later airway hyperreactivity associated with peribronchial inflammation (profibrotic macrophages) and fibrosis compared with infected room air controls, suggesting neonatal oxygen induced hidden molecular changes that prime the lung for hyperreactive airways disease. Although searching for potential activators of TGFβ signaling, we discovered that thrombospondin-1 (TSP-1) is elevated in naïve 40×8 mice compared with controls and localized to lung megakaryocytes and platelets before and during IAV infection. Elevated TSP-1 was also identified in human autopsy samples of former preterm infants with bronchopulmonary dysplasia. These findings reveal how low doses of oxygen that do not durably change lung function may prime it for hyperreactive airways disease by changing expression of genes, such as TSP-1, thus helping to explain why former preterm infants who have normal lung function are susceptible to airway obstruction and increased morbidity after viral infection.

Topics: Animals; Bronchial Hyperreactivity; Bronchopulmonary Dysplasia; Cell Line; Disease Models, Animal; Dogs; Female; Humans; Hyperoxia; Influenza A virus; Influenza, Human; Madin Darby Canine Kidney Cells; Male; Mice; Mice, Inbred C57BL; Orthomyxoviridae Infections; Pulmonary Fibrosis; Thrombospondin 1; Transforming Growth Factor beta

Bronchopulmonary dysplasia (BPD) is a severe chronic lung disease in preterm infants. Circular RNAs (circRNAs) are key regulators of various biological processes. The present study aimed to explore the biological roles of circRNAs in BPD pathogenesis.. A newborn BPD rat model was developed to construct a circRNA library; Illumina deep sequencing (Illumina, San Diego, CA, USA) was used to reveal differential expression of circRNAs in the hyperoxia-induced BPD rat models. Sanger sequencing and a reverse transcription-polymerase chain reaction were performed to confirm circRNAs that may be related to BPD. After miRNA binding-site prediction, we constructed a network diagram of circRNA-competing endogenous RNAs (ceRNAs) related to transforming growth factor (TGF)-β and p53 pathways using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis.. In total, 256 differentially expressed circRNAs were detected between the hyperoxia group and the normoxia group. Of these circRNAs, 195 were up-regulated and 61 were down-regulated. The differences of circRNA distribution between the two groups were analyzed and six circRNAs were validated in the tissue samples. GO analysis indicated that 6519 target genes were enriched in cell location and biological processes. KEGG pathway enrichment analysis showed that circRNAs involved in 242 KEGG pathways. A network diagram of circRNA-ceRNA related to TGF-β and p53 pathways was constructed.. CircRNAs are differentially expressed between the BPD model and control group. Many target genes of circRNAs are involved in the developmental process, which suggests that BPD may be associated with pathways including extracellular matrix-receptor interaction, vascular endothelial growth factor signaling and vascular smooth muscle contraction.

Topics: Animals; Bronchopulmonary Dysplasia; Computational Biology; Disease Models, Animal; Down-Regulation; Gene Expression Profiling; Gene Expression Regulation; Gene Ontology; High-Throughput Nucleotide Sequencing; Humans; Hyperoxia; Immunohistochemistry; Infant, Newborn; Lung; Rats; Rats, Sprague-Dawley; RNA, Circular; Signal Transduction; Transforming Growth Factor beta; Tumor Suppressor Protein p53; Up-Regulation

Bronchopulmonary dysplasia (BPD) is a lung disease of preterm born infants, characterized by alveolar simplification. MicroRNA (. Our results showed that the expression level of. Our results suggest that down-regulation of

Topics: Animals; Bronchopulmonary Dysplasia; Cell Proliferation; Disease Models, Animal; Down-Regulation; Female; Male; Mice; Mice, Inbred C57BL; MicroRNAs; Signal Transduction; Transforming Growth Factor beta

Abnormal alveolar formation and excessive disordered elastin accumulation are key pathological features in bronchopulmonary dysplasia. Transforming growth factor (TGF)-β is an important regulator of the extracellular matrix in the developing lung. To determine if increased TGF-β would injure alveolar development by activating TGF-β signaling and by influencing the expression of elastogenesis-related protein, we performed intraperitoneal injection of newborn mice with the TGF-β-neutralizing antibody 1D11 and observed whether 1D11 had a protective role in the oxygen (O

Topics: Animals; Antibodies, Neutralizing; Bronchopulmonary Dysplasia; Lung; Mice; Mice, Inbred C57BL; Oxygen; Transforming Growth Factor beta

Caffeine is widely used to manage apnea of prematurity, and reduces the incidence of bronchopulmonary dysplasia (BPD). Deregulated transforming growth factor (TGF)-β signaling underlies arrested postnatal lung maturation in BPD. It is unclear whether caffeine impacts TGF-β signaling or postnatal lung development in affected lungs.. Caffeine downregulated expression of type I and type III TGF-β receptors, and Smad2; and potentiated TGF-β signaling in vitro. In vivo, caffeine administration normalized body mass under hyperoxic conditions, and normalized Smad2 phosphorylation detected in lung homogenates; however, caffeine administration neither improved nor worsened lung structure in hyperoxia-exposed mice, in which postnatal lung maturation was blunted.. Caffeine modulated TGF-β signaling in vitro and in vivo. Caffeine administration was well-tolerated by newborn mice, but did not influence the course of blunted postnatal lung maturation in a hyperoxia-based experimental mouse model of BPD.

Topics: Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Caffeine; Cells, Cultured; Disease Models, Animal; Fibroblasts; Hyperoxia; Mice, Inbred C57BL; Phosphorylation; Protein Serine-Threonine Kinases; Proteoglycans; Pulmonary Alveoli; Receptor, Transforming Growth Factor-beta Type I; Receptors, Transforming Growth Factor beta; Signal Transduction; Smad2 Protein; Time Factors; Transforming Growth Factor beta

To determine whether prophylaxis with etanercept, an anti-inflammatory drug, would decrease the severity of lung injury in a neonatal rat model of bronchopulmonary dysplasia (BPD);. Rat pups were divided into three groups: pups exposed to room air (group 1; n = 10), to hyperoxia + placebo (group 2; n = 9), and to hyperoxia + etanercept (group 3; n = 8). Lung morphology was assessed by alveolar surface area percentage, which is a measure of alveolar size. The severities of lung inflammation and antioxidant capacity were assessed by quantifying tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), malondialdehyde (MDA), and superoxide dismutase (SOD) from lung homogenate;. The percentage of alveolar surface areas were significantly higher in group 3 compared to group 2 (p = .004) and similar in both group 1 and group 3 (p = .21). The mean level of lung MDA was significantly higher in group 2 compared to group 1 and group 3 (p < .05 for both). Lung homogenate SOD activities in group 3 was significantly higher than group 2 (p < .001). Furthermore, group 3 pups had lower levels of TNF-α and TGF-β in lung homogenate than that in group 2 (p < .05 for both) but similar in both group 1 and group 3;. Etanercept has favorable effects on alveolarization as well as inflammation and oxidative stress markers in a neonatal rat model of BPD.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Bronchopulmonary Dysplasia; Disease Models, Animal; Etanercept; Female; Humans; Hyperoxia; Infant, Newborn; Infant, Premature; Lung; Male; Malondialdehyde; Oxidative Stress; Rats; Rats, Wistar; Superoxide Dismutase; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha

Septation of the gas-exchange saccules of the morphologically immature mouse lung requires regulated timing, spatial direction, and dosage of transforming growth factor (TGF)-β signaling. We found that neonatal hyperoxia acutely initially diminished saccular TGF-β signaling coincident with alveolar simplification. However, sustained hyperoxia resulted in a biphasic response and subsequent up-regulation of TGF-β signaling, ultimately resulting in bronchopulmonary dysplasia. Significantly, we found that the TGF-β-induced matricellular protein (TGFBI) was similarly biphasically altered in response to hyperoxia. Moreover, genetic ablation revealed that TGFBI was required for normal alveolar structure and function. Although the phenotype was not neonatal lethal, Tgfbi-deficient lungs were morphologically abnormal. Mutant septal tips were stunted, lacked elastin-positive tips, exhibited reduced proliferation, and contained abnormally persistent alveolar α-smooth muscle actin myofibroblasts. In addition, Tgfbi-deficient lungs misexpressed TGF-β-responsive follistatin and serpine 1, and transiently suppressed myofibroblast platelet-derived growth factor α differentiation marker. Finally, despite normal lung volume, Tgfbi-null lungs displayed diminished elastic recoil and gas exchange efficiency. Combined, these data demonstrate that initial suppression of the TGF-β signaling apparatus, as well as loss of key TGF-β effectors (like TGFBI), underlies early alveolar structural defects, as well as long-lasting functional deficits routinely observed in chronic lung disease of infancy patients. These studies underline the complex (and often contradictory) role of TGF-β and indicate a need to design studies to associate alterations with initial appearance of phenotypical changes suggestive of bronchopulmonary dysplasia.

Topics: Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Extracellular Matrix Proteins; Hyperoxia; Lung; Mice; Myofibroblasts; Platelet-Derived Growth Factor; Signal Transduction; Transforming Growth Factor beta; Up-Regulation

Bronchopulmonary dysplasia (BPD) is a main chronic lung disease commonly occurs in preterm infants. BPD is characterized by impaired alveolarization and vascularization of the developing lung. Transforming growth factor-β (TGF-β) signaling pathway is known to play an important role during lung vascular development. In the present study, we examined whether the regulation of TGF-β-ALK-Smad signaling pathway influence on the disruption of pulmonary vascular development in newborn rats as hyperoxia-induced BPD model.. Newborn rats were continuously exposed to 21% or 85% O2 for 7 days, and subsequently kept in normoxic condition for another 14 days. Lung tissues harvested at each time point were evaluated for the expression of TGF-β1, ALK1, ALK5, phosphorylated Smad1/5, phosphorylated Smad2/3, VEGF, and endoglin, as accessed by both biochemical and immunohistological analyses.. Double-fluorescence immunohistochemical staining indicated these molecules were mainly expressed in pulmonary endothelial cells. The expression of TGF-β1 and ALK5 mRNA and protein were significantly increased in D5 hyperoxia group, while that of ALK1 mRNA and protein were significantly decreased. The level of phosphorylated Smad1/5 was significantly decreased in D7 hyperoxia group, whereas that of phosphorylated Smad2/3 was oppositely increased. In addition, the expression of vascular endothelial growth factor (VEGF) mRNA was increased at D1 with subsequent decrease in D7 hyperoxia group. There was no significantly difference in endoglin expression in entire experimental period.. These results indicate that exposure to hyperoxia altered the balance between TGF-β-ALK1-Smad1/5 and TGF-β-ALK5-Smad2/3 pathways in pulmonary endothelial cells, which may ultimately lead to the development of BPD.

Topics: Anaplastic Lymphoma Kinase; Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Hyperoxia; Immunohistochemistry; Lung; Rats; Receptor Protein-Tyrosine Kinases; Signal Transduction; Smad Proteins; Transforming Growth Factor beta

Bronchopulmonary dysplasia (BPD) is a common and serious complication of premature birth, characterized by a pronounced arrest of alveolar development. The underlying pathophysiological mechanisms are poorly understood although perturbations to the maturation and remodeling of the extracellular matrix (ECM) are emerging as candidate disease pathomechanisms. In this study, the expression and regulation of three members of the lysyl hydroxylase family of ECM remodeling enzymes (Plod1, Plod2, and Plod3) in clinical BPD, as well as in an experimental animal model of BPD, were addressed. All three enzymes were localized to the septal walls in developing mouse lungs, with Plod1 also expressed in the vessel walls of the developing lung and Plod3 expressed uniquely at the base of developing septa. The expression of plod1, plod2, and plod3 was upregulated in the lungs of mouse pups exposed to 85% O2, an experimental animal model of BPD. Transforming growth factor (TGF)-β increased plod2 mRNA levels and activated the plod2 promoter in vitro in lung epithelial cells and in lung fibroblasts. Using in vivo neutralization of TGF-β signaling in the experimental animal model of BPD, TGF-β was identified as the regulator of aberrant plod2 expression. PLOD2 mRNA expression was also elevated in human neonates who died with BPD or at risk for BPD, compared with neonates matched for gestational age at birth or chronological age at death. These data point to potential roles for lysyl hydroxylases in normal lung development, as well as in perturbed late lung development associated with BPD.

Topics: Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Cell Line; Epithelial Cells; Female; Humans; Hyperoxia; Infant, Newborn; Lung; Male; Mice; Mice, Inbred C57BL; Pregnancy; Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase; Transforming Growth Factor beta; Up-Regulation

Aberrant remodelling of the extracellular matrix in the developing lung may underlie arrested alveolarisation associated with bronchopulmonary dysplasia (BPD). Transglutaminases are regulators of extracellular matrix remodelling. Therefore, the expression and activity of transglutaminases were assessed in lungs from human neonates with BPD and in a rodent model of BPD. Transglutaminase expression and localisation were assessed by RT-PCR, immunoblotting, activity assay and immunohistochemical analyses of human and mouse lung tissues. Transglutaminase regulation by transforming growth factor (TGF)-β was investigated in lung cells by luciferase-based reporter assay and RT-PCR. TGF-β signalling was neutralised in vivo in an animal model of BPD, to determine whether TGF-β mediated the hyperoxia-induced changes in transglutaminase expression. Transglutaminase 2 expression was upregulated in the lungs of preterm infants with BPD and in the lungs of hyperoxia-exposed mouse pups, where lung development was arrested. Transglutaminase 2 localised to the developing alveolar septa. TGF-β was identified as a regulator of transglutaminase 2 expression in human and mouse lung epithelial cells. In vivo neutralisation of TGF-β signalling partially restored normal lung structure and normalised lung transglutaminase 2 mRNA expression. Our data point to a role for perturbed transglutaminase 2 activity in the arrested alveolarisation associated with BPD.

Topics: Animals; Bronchopulmonary Dysplasia; Epithelial Cells; Extracellular Matrix; Female; Gene Expression Regulation; Gene Expression Regulation, Enzymologic; GTP-Binding Proteins; Humans; Hyperoxia; Infant; Infant, Newborn; Infant, Premature; Lung; Male; Mice; Protein Glutamine gamma Glutamyltransferase 2; Pulmonary Alveoli; Signal Transduction; Transforming Growth Factor beta; Transglutaminases

In bronchopulmonary dysplasia (BPD), alveolar septae are thickened with collagen and α-smooth muscle actin, transforming growth factor (TGF)-β-positive myofibroblasts. Periostin, a secreted extracellular matrix protein, is involved in TGF-β-mediated fibrosis and myofibroblast differentiation. We hypothesized that periostin expression is required for hypoalveolarization and interstitial fibrosis in hyperoxia-exposed neonatal mice, an animal model for this disease. We also examined periostin expression in neonatal lung mesenchymal stromal cells and lung tissue of hyperoxia-exposed neonatal mice and human infants with BPD. Two-to-three day-old wild-type and periostin null mice were exposed to air or 75% oxygen for 14 days. Mesenchymal stromal cells were isolated from tracheal aspirates of premature infants. Hyperoxic exposure of neonatal mice increased alveolar wall periostin expression, particularly in areas of interstitial thickening. Periostin co-localized with α-smooth muscle actin, suggesting synthesis by myofibroblasts. A similar pattern was found in lung sections of infants dying of BPD. Unlike wild-type mice, hyperoxia-exposed periostin null mice did not show larger air spaces or α-smooth muscle-positive myofibroblasts. Compared to hyperoxia-exposed wild-type mice, hyperoxia-exposed periostin null mice also showed reduced lung mRNA expression of α-smooth muscle actin, elastin, CXCL1, CXCL2 and CCL4. TGF-β treatment increased mesenchymal stromal cell periostin expression, and periostin treatment increased TGF-β-mediated DNA synthesis and myofibroblast differentiation. We conclude that periostin expression is increased in the lungs of hyperoxia-exposed neonatal mice and infants with BPD, and is required for hyperoxia-induced hypoalveolarization and interstitial fibrosis.

Topics: Aged; Aged, 80 and over; Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Cell Adhesion Molecules; Cell Differentiation; DNA; Female; Gene Expression Regulation, Developmental; Gene Knockout Techniques; Humans; Hyperoxia; Hypoventilation; Infant, Newborn; Male; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Mice, Knockout; Middle Aged; Myofibroblasts; Phenotype; Pulmonary Alveoli; RNA, Messenger; Transforming Growth Factor beta

There is no effective intervention to prevent or treat bronchopulmonary dysplasia (BPD). Curcumin has potent antioxidant and anti-inflammatory properties, and it modulates signaling of peroxisome proliferator-activated receptor-γ (PPARγ), an important molecule in the pathobiology of BPD. However, its role in the prevention of BPD is not known. We determined 1) if curcumin enhances neonatal lung maturation, 2) if curcumin protects against hyperoxia-induced neonatal lung injury, and 3) if this protection is mediated by blocking TGF-β. Embryonic day 19 fetal rat lung fibroblasts were exposed to 21% or 95% O(2) for 24 h following 1 h of treatment with curcumin. Curcumin dose dependently accelerated e19 fibroblast differentiation [increased parathyroid hormone-related protein (PTHrP) receptor, PPARγ, and adipocyte differentiation-related protein (ADRP) levels and triolein uptake] and proliferation (increased thymidine incorporation). Pretreatment with curcumin blocked the hyperoxia-induced decrease (PPARγ and ADRP) and increase (α-smooth muscle actin and fibronectin) in markers of lung injury/repair, as well as the activation of TGF-β signaling. In a separate set of experiments, neonatal Sprague-Dawley rat pups were exposed to 21% or 95% O(2) for 7 days with or without intraperitoneal administration of curcumin. Analysis for markers of lung injury/repair [PTHrP receptor, PPARγ, ADRP, fibronectin, TGF-β receptor (activin receptor-like kinase 5), and Smad3] and lung morphology (radial alveolar count) demonstrated that curcumin effectively blocks TGF-β activation and hyperoxia-induced lung injury. Therefore, curcumin accelerates lung maturation by stimulating key alveolar epithelial-mesenchymal interactions and prevents hyperoxia-induced neonatal lung injury, possibly by blocking TGF-β activation, suggesting that it is a potential intervention against BPD.

Topics: Animals; Animals, Newborn; Blotting, Western; Bronchopulmonary Dysplasia; Cell Differentiation; Curcumin; Female; Fibroblasts; Gene Expression Regulation; Humans; Hyperoxia; Infant, Newborn; Infant, Newborn, Diseases; Lung; Parathyroid Hormone-Related Protein; Peroxisome Proliferator-Activated Receptors; PPAR gamma; Pregnancy; Rats; Rats, Sprague-Dawley; Receptor, Parathyroid Hormone, Type 1; Signal Transduction; Transforming Growth Factor beta

Disordered extracellular matrix production is a feature of bronchopulmonary dysplasia (BPD). The basis of this phenomenon is not understood.. To assess lysyl oxidase expression and activity in the injured developing lungs of newborn mice and of prematurely born infants with BPD or at risk for BPD.. Pulmonary lysyl oxidase and elastin gene and protein expression were assessed in newborn mice breathing 21 or 85% oxygen, in patients who died with BPD or were at risk for BPD, and in control patients. Signaling by transforming growth factor (TGF-beta) was preemptively blocked in mice exposed to hyperoxia using TGF-beta-neutralizing antibodies. Lysyl oxidase promoter activity was assessed using plasmids containing the lox or loxl1 promoters fused upstream of the firefly luciferase gene.. mRNA and protein levels and activity of lysyl oxidases (Lox, LoxL1, LoxL2) were elevated in the oxygen-injured lungs of newborn mice and infants with BPD or at risk for BPD. In oxygen-injured mouse lungs, increased TGF-beta signaling drove aberrant lox, but not loxl1 or loxl2, expression. Lox expression was also increased in oxygen-injured fibroblasts and pulmonary artery smooth muscle cells.. Lysyl oxidase expression and activity are dysregulated in BPD in injured developing mouse lungs and in prematurely born infants. In developing mouse lungs, aberrant TGF-beta signaling dysregulated lysyl oxidase expression. These data support the postulate that excessive stabilization of the extracellular matrix by excessive lysyl oxidase activity might impede the normal matrix remodeling that is required for pulmonary alveolarization and thereby contribute to the pathological pulmonary features of BPD.

Topics: Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Cell Culture Techniques; Child, Preschool; Disease Models, Animal; Female; Gene Expression; Gene Expression Regulation; Humans; Infant; Infant, Newborn; Infant, Premature; Lung; Male; Mice; Protein-Lysine 6-Oxidase; Pulmonary Alveoli; Reverse Transcriptase Polymerase Chain Reaction; Transforming Growth Factor beta; Up-Regulation

Many extremely preterm infants continue to suffer from bronchopulmonary dysplasia, which results from abnormal saccular-stage lung development. Here, we show that fibroblast growth factor-10 (FGF-10) is required for saccular lung development and reduced in the lung tissue of infants with bronchopulmonary dysplasia. Although exposure to bacteria increases the risk of bronchopulmonary dysplasia, no molecular target has been identified connecting inflammatory stimuli and abnormal lung development. In an experimental mouse model of saccular lung development, activation of Toll-like receptor 2 (TLR2) or Toll-like receptor 4 (TLR4) inhibited FGF-10 expression, leading to abnormal saccular airway morphogenesis. In addition, Toll-mediated FGF-10 inhibition disrupted the normal positioning of myofibroblasts around saccular airways, similar to the mislocalization of myofibroblasts seen in patients with bronchopulmonary dysplasia. Reduced FGF-10 expression may therefore link the innate immune system and impaired lung development in bronchopulmonary dysplasia.

Topics: Animals; Bronchopulmonary Dysplasia; Disease Models, Animal; Female; Fetus; Fibroblast Growth Factor 10; Fibroblasts; Gene Expression Regulation; Humans; Infant, Newborn; Lipopolysaccharides; Lung; Mice; Mice, Inbred BALB C; RNA, Messenger; Toll-Like Receptor 2; Toll-Like Receptor 4; Transforming Growth Factor beta

Prematurely born infants who require oxygen therapy often develop bronchopulmonary dysplasia (BPD), a debilitating disorder characterized by pronounced alveolar hypoplasia. Hyperoxic injury is believed to disrupt critical signaling pathways that direct lung development, causing BPD. We investigated the effects of normobaric hyperoxia on transforming growth factor (TGF)-beta and bone morphogenetic protein (BMP) signaling in neonatal C57BL/6J mice exposed to 21% or 85% O(2) between postnatal days P1 and P28. Growth and respiratory compliance were significantly impaired in pups exposed to 85% O(2), and these pups also exhibited a pronounced arrest of alveolarization, accompanied by dysregulated expression and localization of both receptor (ALK-1, ALK-3, ALK-6, and the TGF-beta type II receptor) and Smad (Smads 1, 3, and 4) proteins. TGF-beta signaling was potentiated, whereas BMP signaling was impaired both in the lungs of pups exposed to 85% O(2) as well as in MLE-12 mouse lung epithelial cells and NIH/3T3 and primary lung fibroblasts cultured in 85% O(2). After exposure to 85% O(2), primary alveolar type II cells were more susceptible to TGF-beta-induced apoptosis, whereas primary pulmonary artery smooth muscle cells were unaffected. Exposure of primary lung fibroblasts to 85% O(2) significantly enhanced the TGF-beta-stimulated production of the alpha(1) subunit of type I collagen (Ialpha(1)), tissue inhibitor of metalloproteinase-1, tropoelastin, and tenascin-C. These data demonstrated that hyperoxia significantly affects TGF-beta/BMP signaling in the lung, including processes central to septation and, hence, alveolarization. The amenability of these pathways to genetic and pharmacological manipulation may provide alternative avenues for the management of BPD.

Topics: Animals; Animals, Newborn; Apoptosis; Bone Morphogenetic Proteins; Bronchopulmonary Dysplasia; Cell Proliferation; Disease Models, Animal; Epithelial Cells; Extracellular Matrix Proteins; Fibroblasts; Gene Expression Regulation; Humans; Hyperoxia; Infant, Newborn; Lung Diseases; Mice; Myocytes, Smooth Muscle; NIH 3T3 Cells; Protein Transport; Pulmonary Alveoli; Pulmonary Artery; Respiration; RNA, Messenger; Signal Transduction; Survival Analysis; Transforming Growth Factor beta

Research interest in bronchopulmonary dysplasia (BPD) has steadily increased, and numerous potential mediators have been implicated in the development of the disease. Among such mediators is transforming growth factor (TGF)-beta. Unfortunately, commonly utilized murine transgenic models are not optimal to investigate the effects of TGF-beta specifically during the 2-3 wk period of alveolar formation, the developmental stage that corresponds histologically to early alveolar development in humans, and the time frame during which BPD develops. In the current study, we utilized a triple-transgenic construct to overexpress bioactive TGF-beta1 in the neonatal mouse lung during the period of alveolar formation. Lungs were then examined by histologic, Western blot, and immunofluorescent methods. We found that overexpression of bioactive TGF-beta1 in neonatal mouse lungs resulted in structural changes that have been described in BPD. Included in those characteristics are abnormal alveolar structure, cellular composition, and vascular development. Our study indicates that TGF-beta1 overexpression in the neonatal mouse lung results in histologic alterations that have striking similarities to pathologic descriptions of BPD. We encourage the use of conditional transgenic models for the study of BPD, and hypothesize that the TGF-beta system is a central mediator for the histologic alterations described in association with the disease.

Topics: Actins; Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Cell Adhesion; Cell Proliferation; Doxycycline; Gene Expression Regulation; Humans; Infant, Newborn; Lung; Mice; Mice, Transgenic; Transforming Growth Factor beta; Transforming Growth Factor beta1; Transgenes

Topics: Anti-Inflammatory Agents; Bronchopulmonary Dysplasia; Dexamethasone; Endothelial Growth Factors; Glucocorticoids; Humans; Infant, Newborn; Infant, Premature; Intercellular Signaling Peptides and Proteins; Lung; Lymphokines; Protein Isoforms; Transforming Growth Factor beta; Transforming Growth Factor beta1; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Bronchopulmonary dysplasia is a chronic lung disease of premature human infancy that shows pathological features comprising varying sized areas of interstitial fibrosis in association with distorted large alveolar spaces. We have previously shown that transfer of active transforming growth factor (TGF)-beta 1 (AdTGF beta 1(223/225)) genes by adenovirus vector to embryonic lungs results in inhibition of branching morphogenesis and primitive peripheral lung development, whereas transfer to adult lungs results in progressive interstitial fibrosis. Herein we show that transfer of TGF-beta1 to newborn rat pups results in patchy areas of interstitial fibrosis developing throughout a period of 28 days after transfer. These areas of fibrosis appear alongside areas of enlarged alveolar spaces similar to the prealveoli seen at birth, suggesting that postnatal lung development and alveolarization has been inhibited. In rats treated with AdTGF beta 1(223/225), enlarged alveolar spaces were evident by day 21, and by 28 days, the mean alveolar cord length was nearly twice that in control vector or untreated rats. Hydroxyproline measurements confirmed the presence of fibrosis. These data suggest that overexpression of TGF-beta 1 during the critical period of postnatal rat lung alveolarization gives rise to pathological, biochemical, and morphological changes consistent with those seen in human bronchopulmonary dysplasia, thus inferring a pathogenic role for TGF-beta in this disorder.

Topics: Animals; Animals, Newborn; Bronchopulmonary Dysplasia; Disease Models, Animal; Gene Transfer Techniques; Humans; Infant, Newborn; Lung; Pulmonary Fibrosis; Rats; Rats, Sprague-Dawley; Transforming Growth Factor beta; Transforming Growth Factor beta1

Topics: Apoptosis; Bronchopulmonary Dysplasia; Chronic Disease; Humans; Infant, Newborn; Infant, Premature; Lung; Receptors, Transforming Growth Factor beta; Transforming Growth Factor beta

The effect of new ventilation strategies on initial pulmonary inflammatory reaction was studied in a surfactant-depleted piglet model. Sixty minutes after induction of lung injury by bronchoalveolar lavage, piglets received either aerosolized FC77 (aerosol-PFC, 10 mL/kg/h, n = 5) or partial liquid ventilation (PLV) with FC77 at functional residual capacity volume (FRC-PLV, 30 mL/kg, n = 5), or at low volume (LV-PLV, 10 mL/kg per hour, n = 5), or intermittent mandatory ventilation (control, n = 5). After 2 h, perfluorocarbon application was stopped and intermittent mandatory ventilation continued for 6 h. After a total experimental period of 8 h, animals were killed and lung tissue obtained. mRNA expression of IL-1beta, IL-6, IL-8, and TGF-beta in porcine lung tissue was quantified using TaqMan real-time PCR and normalized to beta-actin (A) and hypoxanthine-guanine-phosphoribosyl-transferase (H). In the aerosol-PFC group, IL-1beta, IL-6, IL-8, and transforming growth factor (TGF)-beta mRNA expression in lung tissue was significantly lower than in the control group. Reduction was 95% for IL-1beta/H (p < 0.001), 73% for IL-6/H (p < 0.05), 87% for IL-8/H (p < 0.001), and 38% for TGF-beta/H (p < 0.01). A lower mRNA gene expression was also determined for IL-1beta and IL-8 when the aerosol-PFC group was compared with the LV-PLV group [91% for IL-1beta/H (p < 0.001), 75% for IL-8/H (p < 0.001)]. In the FRC-PLV group, mRNA expression of IL-1beta was significantly lower than in the control (p < 0.05) and LV-PLV (p < 0.01) group. In a surfactant-depleted piglet model, aerosol therapy with perfluorocarbon but not LV-PLV reduces the initial pulmonary inflammatory reaction at least as potently as PLV at FRC volume.

Topics: Aerosols; Animals; Bronchopulmonary Dysplasia; Disease Models, Animal; Fluorocarbons; Humans; Infant, Newborn; Interleukin-1; Interleukin-6; Interleukin-8; Lung; Pneumonia; Pulmonary Surfactants; RNA, Messenger; Swine; Transforming Growth Factor beta; Ventilation

Herein we posit that modeling of the lungs during morphogenesis, repair, and regeneration is tightly coordinated by conserved stimulatory and inhibitory signaling mechanisms, including specific transcriptional factors, cytokines, peptide growth factors, proteases, and matrix elements. This evolutionary-developmental (evo-devo) functional conservation has been extended to morphogenesis of the respiratory tracheae in Drosophila. Fifty or more genes direct fruit fly tracheal organogenesis. Among them, hedgehog, patched, smoothened, cubitus interruptus, branchless, breathless, sprouty, decapentaplegic, and mad are functionally conserved between flies, mice, and humans. For example, fibroblast growth factor (FGF) signaling is essential, not only for fly trachea and mouse bronchial branching morphogenesis, but also for postnatal modeling and repair of alveoli. Likewise, sprouty family genes act as inducible negative regulators of FGF signaling, which in part may determine interbranch length during bronchial development. Alveolar epithelial survival, migration, and proliferation during remodeling after hyperoxic injury also require FGF signaling. In addition, FGF signaling appears to regulate a small (< 5%) population of putative alveolar stem/ progenitor cells that express telomerase and are relatively resistant to hyperoxic apoptosis. We speculate that genes in evo-devo functionally conserved signaling pathways such as FGF-FGF receptor-Sprouty may provide novel therapeutic targets to augment lung repair and induce lung regeneration.

Topics: Adult; Animals; Bronchi; Bronchopulmonary Dysplasia; Cell Movement; Cells, Cultured; Diptera; Drosophila; Epitopes; Evolution, Molecular; Fibroblast Growth Factors; Gestational Age; Humans; In Situ Hybridization; Infant, Newborn; Lung; Mice; Morphogenesis; Mutation; Phenotype; Pulmonary Alveoli; Rats; Regeneration; Respiratory System; Stem Cells; Trachea; Transcription Factors; Transforming Growth Factor beta

Prematurely born infants who required assisted ventilation may develop chronic lung disease or bronchopulmonary dysplasia (BPD). The cells involved in the reparative process of the premature lung are not well defined. The repair of injured tissues is a highly standardized process and the most important cells are activated (modulated) fibroblasts (myofibroblasts). A key cytokine in controlling repair is transforming growth factor-beta (TGF-beta). To characterize the cells involved in the repair process of the premature lung, we employed immunocytochemical techniques and examined the lungs of 39 autopsied premature babies who had neonatal respiratory distress syndrome (RDS). All were treated in neonatal intensive care units and required mechanical ventilation and supplemental oxygen; all survived for at least 12 hours. Antibodies were employed against vimentin, alpha-smooth muscle (alpha-SM) actin, total muscle actin, desmin, MAC387, and TGF-beta. Our study indicates that myofibroblasts are normally present along terminal airways in the developing lung. These cells increase in number some days after lung injury, form bundles of cells encircling terminal air spaces, and acquire desmin contractile filaments shortly thereafter. Myofibroblasts do not lose their contractile filaments with time, suggesting a conversion to smooth muscle metaplasia. The proliferation and migration of such myofibroblasts at sites of lung injury is associated with the presence of TGF-beta. These findings suggest that myofibroblasts play an important role in premature lung repair. They may point the way to experimental and clinical trials that will identify drugs antagonistic to TGF-beta (or other cytokines). Such antagonists may protect the neonates who are at high risk of developing BPD.

Topics: Acute Disease; Bronchopulmonary Dysplasia; Chronic Disease; Fibroblasts; Gestational Age; Humans; Immunohistochemistry; Infant, Newborn; Infant, Premature; Infant, Premature, Diseases; Lung; Pulmonary Alveoli; Transforming Growth Factor beta