Biomedical subjects

Wellington V Cardoso

Publications and source records attributed to Wellington V Cardoso.

15 recordsLinked to original sources

PubMed2026

Genetic background influences developmental airway smooth muscle program and susceptibility to airway hyperresponsiveness in mice.

Airway structural remodeling and hyperresponsiveness (AHR), hallmarks of asthma, are influenced by genetic variations and adverse exposures. While intrauterine perturbations in lung development have been linked to adult pulmonary disease, the developmental origins of these abnormalities remain poorly understood. Here, we provide evidence of genetic background playing a key role in this process. Using A/J and C57BL/6J mice known for their distinct susceptibility to AHR, we show that A/J embryos selectively develop an aberrant airway smooth muscle (SM) program and AHR in adulthood when exposed transiently to a vitamin A/retinoic acid (RA)-disrupted intrauterine environment in vivo by maternal BMS493 administration. Single-nucleus multiomics identified a mesenchymal cell population overactivating TGF-β targets in response to BMS493 selectively in A/J lungs. These cells, localized to sites of airway SM initiation and p-SMAD2- and -3, exhibited robust BMS493-mediated upregulation of SMAD2/3 targets, including regulators of SM program Pdgfra and Tnc. Functional analyses in vivo and cultured lungs showed aberrant SM formation in areas of overactive TGF-β of BMS493-exposed lungs. These abnormalities were prevented by inhibiting TGF-β signaling in utero in RA-deficient embryos. These findings underscore how distinct genetic backgrounds respond to intrauterine perturbations that program airway structure and function, with potential lasting consequences in postnatal pulmonary function.

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PubMed2006

Retinoic acid regulates morphogenesis and patterning of posterior foregut derivatives.

Retinoic acid (RA) is an embryonic signaling molecule regulating a wide array of target genes, thereby being a master regulator of patterning and differentiation in a variety of organs. Here we show that mouse embryos deficient for the RA-synthesizing enzyme retinaldehyde dehydrogenase 2 (RALDH2), if rescued from early lethality by maternal RA supplementation between E7.5 and E8.5, lack active RA signaling in the foregut region. The resulting mutants completely fail to develop lungs. Development of more posterior foregut derivatives (stomach and duodenum), as well as liver growth, is also severely affected. A primary lung bud is specified in the RA-deficient embryos, which fails to outgrow due to defective FGF10 signaling and lack of activation of FGF-target genes, such as Pea3 and Bmp4 in the epithelium. Specific Hox and Tbx genes may mediate these RA regulatory effects. Development of foregut derivatives can be partly restored in mutants by extending the RA supplementation until at least E10.5, but lung growth and branching remain defective and a hypoplastic lung develops on the right side only. Such conditions poorly restore FGF10 signaling in the lung buds. Explant culture of RALDH2-deficient foreguts show a capacity to undergo lung budding and early branching in the presence of RA or FGF10. Our data implicate RA as a regulator of gene expression in the early embryonic lung and stomach region upstream of Hox, Tbx and FGF10 signaling.

Aldehyde Oxidoreductases↗

PubMed2006

Distinct roles for retinoic acid receptors alpha and beta in early lung morphogenesis.

Retinoic acid (RA) signaling is required for normal development of multiple organs. However, little is known about how RA influences the initial stages of lung development. Here, we used a combination of genetic, pharmacological and explant culture approaches to address this issue, and to investigate how signaling by different RA receptors (RAR) mediates the RA effects. We analyzed initiation of lung development in retinaldehyde dehydrogenase-2 (Raldh2) null mice, a model in which RA signaling is absent from the foregut from its earliest developmental stages. We provide evidence that RA is dispensable for specification of lung cell fate in the endoderm. By using synthetic retinoids to selectively activate RAR alpha or beta signaling in this model, we demonstrate novel and unique functions of these receptors in the early lung. We show that activation of RAR beta, but not alpha, induces expression of the fibroblast growth factor Fgf10 and bud morphogenesis in the lung field. Similar analysis of wild type foregut shows that endogenous RAR alpha activity is required to maintain overall RA signaling, and to refine the RAR beta effects in the lung field. Our data support the idea that balanced activation of RAR alpha and beta is critical for proper lung bud initiation and endodermal differentiation.

Aldehyde Oxidoreductases↗

PubMed2006

Regulation of early lung morphogenesis: questions, facts and controversies.

During early respiratory system development, the foregut endoderm gives rise to the tracheal and lung cell progenitors. Through branching morphogenesis, and in coordination with vascular development, a tree-like structure of epithelial tubules forms and differentiates to produce the airways and alveoli. Recent studies have implicated the fibroblast growth factor, sonic hedgehog, bone morphogenetic protein, retinoic acid and Wnt signaling pathways, and various transcription factors in regulating the initial stages of lung development. However, the precise roles of these molecules and how they interact in the developing lung is subject to debate. Here, we review early stages in lung development and highlight questions and controversies regarding their molecular regulation.

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PubMed2005

Differential expression of components of the microRNA machinery during mouse organogenesis.

MicroRNA (miRNA)-mediated gene silencing has recently emerged as a major mechanism of gene expression regulation during development in a variety of species. Little is known, however, about the presence of components of miRNA machinery in mammalian organogenesis. In this study, we report that members of the Argonaute (Ago) gene family are expressed in restricted of the day 11.5 and 14.5 embryo, including the brain, neural tube, limb, lungs, and hair follicles. In the developing lung, we found expression of Ago1 and Ago2 localized to branching regions, in distal epithelium and mesenchyme, respectively. These were sites undergoing the most dynamic changes in gene expression and rapid remodeling. We show that Ago1 transcripts are enriched in neural structures at these stages, consistent with the reported role of Drosophila Ago1 in the development of the central nervous system. Our results suggest a role for miRNAs in organogenesis.

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PubMed2004

Identification of FGF10 targets in the embryonic lung epithelium during bud morphogenesis.

Genetic studies implicate Fgf10-Fgfr2 signaling as a critical regulator of bud morphogenesis in the embryo. However, little is known about the transcriptional targets of Fgf10 during this process. Here we identified global changes in gene expression in lung epithelial explants undergoing FGF10-mediated budding in the absence of other growth factors and mesenchyme. Targets were confirmed by their localization at sites where endogenous Fgf10 signaling is active in embryonic lungs and by demonstrating their induction in intact lungs in response to local application of FGF10 protein. We show that the initial stages of budding are characterized by marked up-regulation of genes associated with cell rearrangement and cell migration, inflammatory process, and lipid metabolism but not cell proliferation. We also found that some genes implicated in tumor invasion and metastatic behavior are epithelial targets of Fgf10 in the lung and other developing organs that depend on Fgf10-Fgfr2 signaling to properly form. Our approach identifies Fgf10 targets that are common to multiple biological processes and provides insights into potential mechanisms by which Fgf signaling regulates epithelial cell behavior.

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PubMed2004

Retinoic acid selectively regulates Fgf10 expression and maintains cell identity in the prospective lung field of the developing foregut.

Although respiratory tract defects that result from disruption of retinoic acid (RA) signaling have been widely reported, the mechanism by which endogenous RA regulates early lung morphogenesis is unknown. Here, we provide novel evidence that a major role for RA is to selectively maintain mesodermal proliferation and induce fibroblast growth factor 10 (Fgf10) expression in the foregut region where the lung forms. By using a pan-RAR antagonist (BMS493) in foregut explant cultures, we show that bud initiation is selectively blocked in the prospective respiratory region by failure to induce Fgf10 in the corresponding mesoderm. The RA regulation of Fgf10 expression occurs only in this region, within a defined developmental window, and is not seen in other foregut derivatives such as thyroid and pancreas where Fgf10 is also required for normal development. Furthermore, we show that RA activity is essential in the lung field to maintain lung cell identity in the endoderm; RAR antagonism disrupts expression of thyroid transcription factor 1 (Ttf1), an early marker of the respiratory region in the endoderm, and surfactant protein C (Sp-C) mRNAs. Our observations in mouse foregut cultures are corroborated by data from an in vivo model of vitamin A deficiency in rats. Our study supports RA as an essential regulator of gene expression and cellular activities during primary bud formation.

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PubMed2004

Global analysis of genes differentially expressed in branching and non-branching regions of the mouse embryonic lung.

During development, the proximal and distal regions of respiratory tract undergo distinct processes that ultimately give rise to conducting airways and alveoli. To gain insights into the genetic pathways differentially activated in these regions when branching morphogenesis is initiating, we characterized their transcriptional profiles in murine rudiments isolated at embryonic (E) day 11.5. By using oligonucleotide microarrays, we identified 83 and 128 genes preferentially expressed in branching and non-branching regions, respectively. The majority of these genes (85%) had not been previously described in the lung, or in other organs. We report restricted expression patterns of 22 of these genes were by in situ hybridization. Among them in the lung potential components of the Wnt, TGF beta, FGF and retinoid pathways identified in other systems, and uncharacterized genes, such as translocases, small GTPases and splicing factors. In addition, we provide a more detailed analysis of the expression pattern and regulation of a representative gene from the distal (transforming growth factor, beta induced) and proximal (WW domain-containing protein 2) regions. Our data suggest that these genes may regulate focal developmental events specific of each of these regions during respiratory tract formation.

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PubMed2004

Effect of 5-lipoxygenase on the development of pulmonary hypertension in rats.

5-Lipoxygenase (5-LO) and its downstream leukotriene products have been implicated in the development of pulmonary hypertension. In this study, we examined the effects of 5-LO overexpression in rat lungs on pulmonary hypertension using a recombinant adenovirus expressing 5-LO (Ad5-LO). Transthoracic echocardiography and right heart catheterization data showed that 5-LO overexpression in the lung did not cause pulmonary hypertension in normal rats; however, it markedly accelerated the progression of pulmonary hypertension in rats treated with monocrotaline (MCT). An increase in pulmonary artery pressure occurred earlier in the rats treated with MCT + Ad5-LO (7-10 days) compared with those treated with control vector, MCT + adenovirus expressing green fluorescent protein (AdGFP), or MCT alone (15-18 days). The weight ratio of the right ventricle to left ventricle plus septum was higher in the MCT + Ad5-LO group than that of the MCT + AdGFP or MCT group (0.45 +/- 0.08 vs. 0.35 +/- 0.03 or 0.33 +/- 0.06). Lung tissue histological sections from MCT + Ad5-LO rats exhibited more severe inflammatory cell infiltration and pulmonary vascular muscularization than those from MCT + AdGFP- or MCT-treated rats. Administration of 5-LO inhibitors, zileuton or MK-886, to either MCT- or MCT + Ad5-LO-treated rats prevented the development of pulmonary hypertension. These data suggest that 5-LO plays a critical role in the progression of pulmonary hypertension in rats and that the detrimental effect of 5-LO is manifest only in the setting of pulmonary vascular endothelial cell dysfunction.

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PubMed2004

Differential expression of heparan sulfate 6-O-sulfotransferase isoforms in the mouse embryo suggests distinctive roles during organogenesis.

Heparan sulfate (HS) interactions with secreted morphogens such as fibroblast growth factors, hedgehogs, and Wnts are essential for embryonic development. Formation of biologically relevant HS structures is a result of the coordinated action of various biosynthetic enzymes. HS 6-O-sulfotransferases (6OST) catalyze the transfer of sulfate groups to the 6-O position of glucosamine residues in HS. Three 6OST isoforms have been described in the mouse; however, little is known about their role in generating specific HS protein-binding sequences, expression pattern, and function in vivo. To gain insights into the distribution of these isoforms and their potential role in development, we mapped 6OST1-3 gene expression during mouse organogenesis. We report dynamic expression of these isoforms with striking differences in tissue distribution in many developing organs. We show that 6OST transcripts are differentially expressed in several sites where heparin-binding growth factors are critical for development. 6OST1 is predominantly transcribed in epithelial and neural-derived tissues, whereas 6OST2 is more mesenchymal. 6OST3 appears at later stages and in a more restricted manner. The patterns reported here strongly suggest that the HS structures modified by these enzymes have different roles in growth factor-induced developmental processes.

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PubMed2003

A caudorostral wave of RALDH2 conveys anteroposterior information to the cardiac field.

Establishment of anteroposterior (AP) polarity is one of the earliest decisions in cardiogenesis and plays an important role in the coupling between heart and blood vessels. Recent research implicated retinoic acid (RA) in the communication of AP polarity to the heart. We utilized embryo culture, in situ hybridization, morphometry, fate mapping and treatment with the RA pan-antagonist BMS493 to investigate the relationship between cardiac precursors and RA signalling. We describe two phases of AP signalling by RA, reflected in RALDH2 expression. The first phase (HH4-7) is characterized by increasing proximity between sino-atrial precursors and the lateral mesoderm expressing RALDH2. In this phase, RA signalling is consistent with diffusion of the morphogen from a large field rather than a single hot spot. The second phase (HH7-8) is characterized by progressive encircling of cardiac precursors by a field of RALDH2 originating from a dynamic and evolutionary-conserved caudorostral wave pattern in the lateral mesoderm. At this phase, cardiac AP patterning by RA is consistent with localized action of RA by regulated activation of the Raldh2 gene within an embryonic domain. Systemic treatment with BMS493 altered the cardiac fate map such that ventricular precursors were found in areas normally devoid of them. Topical application of BMS493 inhibited atrial differentiation in left anterior lateral mesoderm. Identification of the caudorostral wave of RALDH2 as the endogenous source of RA establishing cardiac AP fates provides a useful model to approach the mechanisms whereby the vertebrate embryo confers axial information on its organs.

Aldehyde Oxidoreductases↗

PubMed2003

Down-regulation of retinoic acid receptor alpha signaling is required for sacculation and type I cell formation in the developing lung.

Although retinoic acid (RA) has been shown to be critical for lung development, little is known about when RA is required and the role of individual RA receptors (RAR) in this process. Previously reported data from an RA responsive element RARE-lacZ reporter mouse show that when epithelial tubules are branching and differentiating RA signaling becomes markedly down-regulated in the epithelium. It is unclear why this down-regulation occurs and what role it might play in the developing lung. Here we analyze the effects of preventing potential progenitors of the distal lung from turning off RA signaling by locally expressing constitutively activated RARalpha or RARbeta chimeric receptors (RARVP16) in branching airways of transgenic mice. Continued RA activation resulted in lung immaturity in both cases, but the phenotypes were remarkably different. RARalphaVP16 lungs did not expand to form saccules or morphologically identifiable type I cells. High levels of surfactant protein C (Sp-C), thyroid transcription factor-1 (Ttf1), and Gata6, but not Sp-A or Sp-B in the epithelium at birth suggested that in these lungs differentiation was arrested at an early stage. These alterations were not observed in RARbetaVP16 lungs, which showed relatively less severe changes. Our data suggest a model in which activation of RAR signaling at the onset of lung development establishes an initial program that assigns distal cell fate to the prospective lung epithelium. Down-regulation of RA signaling, however, is required to allow completion of later steps of this differentiation program that ultimately form mature type I and II cells.

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PubMed2003

Heparan sulfates expressed in the distal lung are required for Fgf10 binding to the epithelium and for airway branching.

Fibroblast growth factor (Fgf) 10 is a critical regulator of bud formation during lung morphogenesis. fgf10 is expressed in distal lung mesenchyme at sites of prospective budding from the earliest developmental stages and signals through its epithelial receptor Fgfr2b. Experiments in intact lung organ cultures demonstrate that Fgf10 is a chemotactic factor for distal, but not for proximal, epithelium. This differential response suggests the involvement of an additional mechanism regulating Fgf10-Fgfr2b interactions, because Fgfr2b is uniformly expressed throughout the respiratory tract. Here we use an immunohistochemistry-based binding assay to show that O-sulfated heparan sulfates (HS) are critical for Fgf10 binding to the distal epithelium. We show that altering endogenous gradients of HS sulfation with sodium chlorate or over-O-sulfated synthetic heparin in lung organ cultures dramatically decreases Fgf10 binding. Moreover, we show that under these conditions epithelial binding is not improved by providing exogenous FGF10. Our data suggest that, not only ligand availability, but also the presence of specific patterns of HS modification in the distal lung epithelium are critical determinants of Fgf10 binding to the epithelium and signaling.

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PubMed2003

Heparan sulfate-FGF10 interactions during lung morphogenesis.

Signaling by fibroblast growth factor 10 (FGF10) through FGFR2b is essential for lung development. Heparan sulfates (HS) are major modulators of growth factor binding and signaling present on cell surfaces and extracellular matrices of all tissues. Although recent studies provide evidence that HS are required for FGF-directed tracheal morphogenesis in Drosophila, little is known about the HS role in FGF10-mediated bud formation in the vertebrate lung. Here, we mapped HS expression in the early lung and we investigated how HS interactions with FGF10-FGFR2b influence lung morphogenesis. Our data show that a specific set of HS low in O-sulfates is dynamically expressed in the lung mesenchyme at the sites of prospective budding near Fgf10-expressing areas. In turn, highly sulfated HS are present in basement membranes of branching epithelial tubules. We show that disrupting endogenous gradients of HS or altering HS sulfation in embryonic lung culture systems prevents FGF10 from inducing local responses and markedly alters lung pattern formation and gene expression. Experiments with selectively sulfated heparins indicate that O-sulfated groups in HS are critical for FGF10 signaling activation in the epithelium during lung bud formation, and that the effect of FGF10 in pattern is in part determined by regional distribution of O-sulfated HS. Moreover, we describe expression of a HS 6-O-sulfotransferase preferentially at the tips of branching tubules. Our data suggest that the ability of FGF10 to induce local budding is critically influenced by developmentally regulated regional patterns of HS sulfation.

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PubMed2001

Growth factors in lung development and disease: friends or foe?

Growth factors mediate tissue interactions and regulate a variety of cellular functions that are critical for normal lung development and homeostasis. Besides their involvement in lung pattern formation, growth and cell differentiation during organogenesis, these factors have been also implicated in modulating injury-repair responses of the adult lung. Altered expression of growth factors, such as transforming growth factor beta1, vascular endothelial growth factor and epidermal growth factor, and/or their receptors, has been found in a number of pathological lung conditions. In this paper, we discuss the dual role of these molecules in mediating beneficial feedback responses or responses that can further damage lung integrity; we shall also discuss the basis for their prospective use as therapeutic agents.

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