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Jank M, Schwartz J, Miyake Y, Ozturk Aptekmann A, Patel D, Boettcher M, Keijzer R. Dysregulation of CITED2 in abnormal lung development in the nitrofen rat model. Pediatr Surg Int 2024; 40:43. [PMID: 38291157 DOI: 10.1007/s00383-023-05607-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/22/2023] [Indexed: 02/01/2024]
Abstract
PURPOSE CITED2 both modulates lung, heart and diaphragm development. The role of CITED2 in the pathogenesis of congenital diaphragmatic hernia (CDH) is unknown. We aimed to study CITED2 during abnormal lung development in the nitrofen model. METHODS Timed-pregnant rats were given nitrofen on embryonic day (E) 9 to induce CDH. Fetal lungs were harvested on E15, 18 and 21. We performed RT-qPCR, RNAscope™ in situ hybridization and immunofluorescence staining for CITED2. RESULTS We observed no difference in RT-qPCR (control: 1.09 ± 0.22 and nitrofen: 0.95 ± 0.18, p = 0.64) and in situ hybridization (1.03 ± 0.03; 1.04 ± 0.03, p = 0.97) for CITED2 expression in E15 nitrofen and control pups. At E18, CITED2 expression was reduced in in situ hybridization of nitrofen lungs (1.47 ± 0.05; 1.14 ± 0.07, p = 0.0006), but not altered in RT-qPCR (1.04 ± 0.16; 0.81 ± 0.13, p = 0.33). In E21 nitrofen lungs, CITED2 RNA expression was increased in RT-qPCR (1.04 ± 0.11; 1.52 ± 0.17, p = 0.03) and in situ hybridization (1.08 ± 0.07, 1.29 ± 0.04, p = 0.02). CITED2 protein abundance was higher in immunofluorescence staining of E21 nitrofen lungs (2.96 × 109 ± 0.13 × 109; 4.82 × 109 ± 0.25 × 109, p < 0.0001). CONCLUSION Our data suggest that dysregulation of CITED2 contributes to abnormal lung development of CDH, as demonstrated by the distinct spatial-temporal distribution in nitrofen-induced lungs.
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MESH Headings
- Animals
- Female
- Pregnancy
- Rats
- 2,4-Dinitrophenol
- Disease Models, Animal
- Gene Expression Regulation, Developmental
- Hernias, Diaphragmatic, Congenital/chemically induced
- Hernias, Diaphragmatic, Congenital/genetics
- Hernias, Diaphragmatic, Congenital/metabolism
- Lung/abnormalities
- Lung Diseases/metabolism
- Phenyl Ethers/toxicity
- Rats, Sprague-Dawley
- Respiratory System Abnormalities
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Affiliation(s)
- Marietta Jank
- Department of Surgery, Division of Pediatric Surgery, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, and Children's Hospital Research Institute of Manitoba, AE402-820 Sherbrook Street, Winnipeg, MB, R3A 1S1, Canada
- Department of Pediatric Surgery, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany
| | - Jacquelyn Schwartz
- Department of Surgery, Division of Pediatric Surgery, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, and Children's Hospital Research Institute of Manitoba, AE402-820 Sherbrook Street, Winnipeg, MB, R3A 1S1, Canada
| | - Yuichiro Miyake
- Department of Surgery, Division of Pediatric Surgery, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, and Children's Hospital Research Institute of Manitoba, AE402-820 Sherbrook Street, Winnipeg, MB, R3A 1S1, Canada
- Department of Pediatric General and Urogenital Surgery, Juntendo University School of Medicine, Tokyo, Japan
| | - Arzu Ozturk Aptekmann
- Department of Surgery, Division of Pediatric Surgery, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, and Children's Hospital Research Institute of Manitoba, AE402-820 Sherbrook Street, Winnipeg, MB, R3A 1S1, Canada
| | - Daywin Patel
- Department of Surgery, Division of Pediatric Surgery, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, and Children's Hospital Research Institute of Manitoba, AE402-820 Sherbrook Street, Winnipeg, MB, R3A 1S1, Canada
| | - Michael Boettcher
- Department of Pediatric Surgery, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany
| | - Richard Keijzer
- Department of Surgery, Division of Pediatric Surgery, Rady Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, and Children's Hospital Research Institute of Manitoba, AE402-820 Sherbrook Street, Winnipeg, MB, R3A 1S1, Canada.
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2
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Chen J, Mishra R, Yu Y, McDonald JG, Eckert KM, Gao L, Mendelson CR. Decreased 11β-hydroxysteroid dehydrogenase 1 in lungs of steroid receptor coactivator (Src)-1/-2 double-deficient fetal mice is caused by impaired glucocorticoid and cytokine signaling. FASEB J 2020; 34:16243-16261. [PMID: 33070362 DOI: 10.1096/fj.202001809r] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 09/11/2020] [Accepted: 09/29/2020] [Indexed: 01/30/2023]
Abstract
Our previous research revealed that steroid receptor coactivators (Src)-1 and -2 serve a critical cooperative role in production of parturition signals, surfactant protein A and platelet-activating factor, by the developing mouse fetal lung (MFL). To identify the global landscape of genes in MFL affected by Src-1/-2 double-deficiency, we conducted RNA-seq analysis of lungs from 18.5 days post-coitum (dpc) Src-1-/- /-2-/- (dKO) vs. WT fetuses. One of the genes most highly downregulated (~4.8 fold) in Src-1/-2 dKO fetal lungs encodes 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which catalyzes conversion of inactive 11-dehydrocorticosterone to the glucocorticoid receptor (GR) ligand, corticosterone. Glucocorticoids were reported to upregulate 11β-HSD1 expression in various cell types via induction of C/EBP transcription factors. We observed that C/ebpα and C/ebpβ mRNA and protein were markedly reduced in Src-1/-2 double-deficient (Src-1/-2d/d ) fetal lungs, compared to WT. Moreover, glucocorticoid induction of 11β-hsd1, C/ebpα and C/ebpβ in cultured MFL epithelial cells was prevented by the SRC family inhibitor, SI-2. Cytokines also contribute to the induction of 11β-HSD1. Expression of IL-1β and TNFα, which dramatically increased toward term in lungs of WT fetuses, was markedly reduced in Src-1/-2d/d fetal lungs. Our collective findings suggest that impaired lung development and surfactant synthesis in Src-1/-2d/d fetuses are likely caused, in part, by decreased GR and cytokine induction of C/EBP and NF-κB transcription factors. This results in reduced 11β-HSD1 expression and glucocorticoid signaling within the fetal lung, causing a break in the glucocorticoid-induced positive feedforward loop.
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Affiliation(s)
- Jingfei Chen
- Department of Obstetrics and Gynecology, Xiangya Hospital of Central South University, Changsha, China.,Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Ritu Mishra
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yaqin Yu
- Department of Physiology, Second Military Medical University, Shanghai, P.R. China
| | - Jeffrey G McDonald
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kaitlyn M Eckert
- Center for Human Nutrition, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Lu Gao
- Department of Physiology, Second Military Medical University, Shanghai, P.R. China.,School of Medicine, The International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Carole R Mendelson
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA.,Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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3
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Ito Y, Ahmad A, Kewley E, Mason RJ. Hypoxia-inducible factor regulates expression of surfactant protein in alveolar type II cells in vitro. Am J Respir Cell Mol Biol 2011; 45:938-45. [PMID: 21454802 DOI: 10.1165/rcmb.2011-0052oc] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Alveolar type II (ATII) cells cultured at an air-liquid (A/L) interface maintain differentiation, but they lose these properties when they are submerged. Others showed that an oxygen tension gradient develops in the culture medium as ATII cells consume oxygen. Therefore, we wondered whether hypoxia inducible factor (HIF) signaling could explain differences in the phenotypes of ATII cells cultured under A/L interface or submerged conditions. ATII cells were isolated from male Sprague-Dawley rats and cultured on inserts coated with a mixture of rat-tail collagen and Matrigel, in medium including 5% rat serum and 10 ng/ml keratinocyte growth factor, with their apical surfaces either exposed to air or submerged. The A/L interface condition maintained the expression of surfactant proteins, whereas that expression was down-regulated under the submerged condition, and the effect was rapid and reversible. Under submerged conditions, there was an increase in HIF1α and HIF2α in nuclear extracts, mRNA levels of HIF inducible genes, vascular endothelial growth factor, glucose transporter-1 (GLUT1), and the protein level of pyruvate dehydrogenase kinase isozyme-1. The expression of surfactant proteins was suppressed and GLUT1 mRNA levels were induced when cells were cultured with 1 mM dimethyloxalyl glycine. The expression of surfactant proteins was restored under submerged conditions with supplemented 60% oxygen. HIF signaling and oxygen tension at the surface of cells appears to be important in regulating the phenotype of rat ATII cells.
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Affiliation(s)
- Yoko Ito
- Department of Medicine, National Jewish Health, Denver, CO 80206, USA.
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4
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Bein K, Leight H, Leikauf GD. JUN-CCAAT/enhancer-binding protein complexes inhibit surfactant-associated protein B promoter activity. Am J Respir Cell Mol Biol 2010; 45:436-44. [PMID: 21148742 DOI: 10.1165/rcmb.2010-0260oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The murine surfactant-associated protein B (Sftpb) gene promoter, spanning nucleotides -653 to +42, is composed of functionally distinct proximal and distal regions. Although both regions contain consensus/putative activator protein 1 (AP-1) sites, the distal, but not the proximal, region mediates the inhibition by jun proto-oncogene (JUN) of Sftpb promoter activity. In transient cotransfection assays, JUN inhibited the luciferase reporter activity of plasmid constructs containing Sftpb promoter fragments that lacked the distal putative AP-1 site, indicating that another regulatory motif mediates JUN-dependent inhibition. Electrophoretic mobility shift assays and in silico analyses identified a DNA target sequence (Sftpb nucleotides -339 to -316) and transcription factors that regulate Sftpb promoter activity. The identified sequence contains a CCAAT/enhancer-binding protein (C/EBP) consensus recognition element. Mutation of the site reduced Sftpb promoter activity and sensitivity to inhibition by JUN. Purified recombinant JUN, which did not recognize the -339 to -316 target sequence when added alone, supershifted the mobility of in vitro translated C/EBP-α and C/EBP-β proteins complexed with the identified cis-regulatory element. These findings support the idea that heterodimerization between JUN and C/EBP-α and/or C/EBP-β targets JUN to the Sftpb promoter, thereby mediating its inhibitory regulatory role.
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Affiliation(s)
- Kiflai Bein
- Department of Environmental and Occupational Health, Graduate School of Public Health, University of Pittsburgh, PA 15219-3130, USA.
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5
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Repression of transcriptional activity of C/EBPalpha by E2F-dimerization partner complexes. Mol Cell Biol 2010; 30:2293-304. [PMID: 20176812 DOI: 10.1128/mcb.01619-09] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The transcription factor CCAAT/enhancer-binding protein alpha (C/EBPalpha) coordinates proliferation arrest and the differentiation of myeloid progenitors, adipocytes, hepatocytes, keratinocytes, and cells of the lung and placenta. C/EBPalpha transactivates lineage-specific differentiation genes and inhibits proliferation by repressing E2F-regulated genes. The myeloproliferative C/EBPalpha BRM2 mutant serves as a paradigm for recurrent human C-terminal bZIP C/EBPalpha mutations that are involved in acute myeloid leukemogenesis. BRM2 fails to repress E2F and to induce adipogenesis and granulopoiesis. The data presented here show that, independently of pocket proteins, C/EBPalpha interacts with the dimerization partner (DP) of E2F and that C/EBPalpha-E2F/DP interaction prevents both binding of C/EBPalpha to its cognate sites on DNA and transactivation of C/EBP target genes. The BRM2 mutant, in addition, exhibits enhanced interaction with E2F-DP and reduced affinity toward DNA and yet retains transactivation potential and differentiation competence that becomes exposed when E2F/DP levels are low. Our data suggest a tripartite balance between C/EBPalpha, E2F/DP, and pocket proteins in the control of proliferation, differentiation, and tumorigenesis.
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6
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Sai S, Esteves CL, Kelly V, Michailidou Z, Anderson K, Coll AP, Nakagawa Y, Ohzeki T, Seckl JR, Chapman KE. Glucocorticoid regulation of the promoter of 11beta-hydroxysteroid dehydrogenase type 1 is indirect and requires CCAAT/enhancer-binding protein-beta. Mol Endocrinol 2008; 22:2049-60. [PMID: 18617597 DOI: 10.1210/me.2007-0489] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
11beta-Hydroxysteroid dehydrogenase type 1 (11beta-HSD1) converts inert 11keto-glucocorticoids to active 11beta-hydroxy forms, thereby amplifying intracellular glucocorticoid action. Up-regulation of 11beta-HSD1 in adipose tissue and liver is of pathogenic importance in metabolic syndrome. However, the mechanisms controlling 11beta-HSD1 transcription are poorly understood. Glucocorticoids themselves potently increase 11beta-HSD1 expression in many cells, providing a potential feed-forward system to pathology. We have investigated the molecular mechanisms by which glucocorticoids regulate transcription of 11beta-HSD1, exploiting an A549 cell model system in which endogenous 11beta-HSD1 is expressed and is induced by dexamethasone. We show that glucocorticoid induction of 11beta-HSD1 is indirect and requires new protein synthesis. A glucocorticoid-responsive region maps to between -196 and -88 with respect to the transcription start site. This region contains two binding sites for CCAAT/enhancer-binding protein (C/EBP) that together are essential for the glucocorticoid response and that bind predominantly C/EBPbeta, with C/EBPdelta present in a minority of the complexes. Both C/EBPbeta and C/EBPdelta are rapidly induced by glucocorticoids in A549 cells, but small interfering RNA-mediated knockdown shows that only C/EBPbeta reduction attenuates the glucocorticoid induction of 11beta-HSD1. Chromatin immunoprecipitation studies demonstrated increased binding of C/EBPbeta to the 11beta-HSD1 promoter in A549 cells after glucocorticoid treatment. A similar mechanism may apply in adipose tissue in vivo where increased C/EBPbeta mRNA levels after glucocorticoid treatment were associated with increased 11beta-HSD1 expression. C/EBPbeta is a key mediator of metabolic and inflammatory signaling. Positive regulation of 11beta-HSD1 by C/EBPbeta may link amplification of glucocorticoid action with metabolic and inflammatory pathways and may represent an endogenous innate host-defense mechanism.
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Affiliation(s)
- Shuji Sai
- Endocrinology Unit, Centre for Cardiovascular Sciences, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
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7
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Paz-Priel I, Cai DH, Wang D, Kowalski J, Blackford A, Liu H, Heckman CA, Gombart AF, Koeffler HP, Boxer LM, Friedman AD. CCAAT/enhancer binding protein alpha (C/EBPalpha) and C/EBPalpha myeloid oncoproteins induce bcl-2 via interaction of their basic regions with nuclear factor-kappaB p50. Mol Cancer Res 2006; 3:585-96. [PMID: 16254192 DOI: 10.1158/1541-7786.mcr-05-0111] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The CEBPA gene is mutated in 10% of acute myeloid leukemia (AML) cases. We find that CEBPA and Bcl-2 RNA levels correlate highly in low-risk human AMLs, suggesting that inhibition of apoptosis via induction of bcl-2 by CCAAT/enhancer binding protein alpha (C/EBPalpha) or its mutant variants contributes to transformation. C/EBPalphap30, lacking a NH2-terminal transactivation domain, or C/EBPalphaLZ, carrying in-frame mutations in the leucine zipper that prevent DNA binding, induced bcl-2 in hematopoietic cell lines, and C/EBPalpha induced bcl-2 in normal murine myeloid progenitors and in the splenocytes of H2K-C/EBPalpha-Emu transgenic mice. C/EBPalpha protected Ba/F3 cells from apoptosis on interleukin-3 withdrawal but not if bcl-2 was knocked down. Remarkably, C/EBPalphaLZ oncoproteins activated the bcl-2 P2 promoter despite lack of DNA binding, and C/EBPalphap30 also activated the promoter. C/EBPalpha and the C/EBPalpha oncoproteins cooperated with nuclear factor-kappaB (NF-kappaB) p50, but not p65, to induce bcl-2 transcription. Endogenous C/EBPalpha preferentially coimmunoprecipitated with p50 versus p65 in myeloid cell extracts. Mutation of residues 297 to 302 in the C/EBPalpha basic region prevented induction of endogenous bcl-2 or the bcl-2 promoter and interaction with p50 but not p65. These findings suggest that C/EBPalpha or its mutant variants tether to a subset of NF-kappaB target genes, including Bcl-2, via p50 to facilitate gene activation and offer an explanation for preferential in-frame rather than out-of-frame mutation of the leucine zipper with sparing of the basic region in C/EBPalphaLZ oncoproteins. Targeting interaction between C/EBPalpha basic region and NF-kappaB p50 may contribute to the therapy of AML and other malignancies expressing C/EBPs.
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MESH Headings
- Adult
- Animals
- Apoptosis/physiology
- CCAAT-Enhancer-Binding Protein-alpha/genetics
- CCAAT-Enhancer-Binding Protein-alpha/metabolism
- Cell Line
- HL-60 Cells
- Hematopoietic Stem Cells/cytology
- Hematopoietic Stem Cells/metabolism
- Humans
- Leukemia, Myeloid, Acute/enzymology
- Leukemia, Myeloid, Acute/genetics
- Leukemia, Myeloid, Acute/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Transgenic
- NF-kappa B p50 Subunit/metabolism
- Oncogene Proteins/genetics
- Oncogene Proteins/metabolism
- Promoter Regions, Genetic
- Proto-Oncogene Proteins c-bcl-2/biosynthesis
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Rats
- Transcriptional Activation
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Affiliation(s)
- Ido Paz-Priel
- Division of Pediatric Oncology, Johns Hopkins University, CRB 253, 1650 Orleans Street, Baltimore, Maryland 21231, USA
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8
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Martis PC, Whitsett JA, Xu Y, Perl AKT, Wan H, Ikegami M. C/EBPalpha is required for lung maturation at birth. Development 2006; 133:1155-64. [PMID: 16467360 DOI: 10.1242/dev.02273] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Epithelial cells lining the peripheral lung synthesize pulmonary surfactant that reduces surface tension at the air-liquid interface. Lack of surfactant lipids and proteins in the lungs causes respiratory distress syndrome, a common cause of morbidity and mortality in preterm infants. We show that C/EBPalpha plays a crucial role in the maturation of the respiratory epithelium in late gestation, being required for the production of surfactant lipids and proteins necessary for lung function. Deletion of the Cebpa gene in respiratory epithelial cells in fetal mice caused respiratory failure at birth. Structural and biochemical maturation of the lung was delayed. Normal synthesis of surfactant lipids and proteins, including SP-A, SP-B, SP-C, SP-D, ABCA3 (a lamellar body associated protein) and FAS (precursor of fatty acid synthesis) were dependent upon expression of the C/EBPalpha in respiratory epithelial cells. Deletion of the Cebpa gene caused increased expression of Tgfb2, a growth factor that inhibits lung epithelial cell proliferation and differentiation. Normal expression of C/EBPalpha required Titf1 and Foxa2, transcription factors that also play an important role in perinatal lung differentiation. C/EBPalpha participates in a transcriptional network that is required for the regulation of genes mediating perinatal lung maturation and surfactant homeostasis that is necessary for adaptation to air breathing at birth.
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Affiliation(s)
- Prithy C Martis
- Division of Pulmonary Biology and Neonatology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
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9
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Bassères DS, Levantini E, Ji H, Monti S, Elf S, Dayaram T, Fenyus M, Kocher O, Golub T, Wong KK, Halmos B, Tenen DG. Respiratory failure due to differentiation arrest and expansion of alveolar cells following lung-specific loss of the transcription factor C/EBPalpha in mice. Mol Cell Biol 2006; 26:1109-23. [PMID: 16428462 PMCID: PMC1347037 DOI: 10.1128/mcb.26.3.1109-1123.2006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2005] [Revised: 10/12/2005] [Accepted: 11/14/2005] [Indexed: 01/10/2023] Open
Abstract
The leucine zipper family transcription factor CCAAT enhancer binding protein alpha (C/EBPalpha) inhibits proliferation and promotes differentiation in various cell types. In this study, we show, using a lung-specific conditional mouse model of C/EBPalpha deletion, that loss of C/EBPalpha in the respiratory epithelium leads to respiratory failure at birth due to an arrest in the type II alveolar cell differentiation program. This differentiation arrest results in the lack of type I alveolar cells and differentiated surfactant-secreting type II alveolar cells. In addition to showing a block in type II cell differentiation, the neonatal lungs display increased numbers of proliferating cells and decreased numbers of apoptotic cells, leading to epithelial expansion and loss of airspace. Consistent with the phenotype observed, genes associated with alveolar maturation, survival, and proliferation were differentially expressed. Taken together, these results identify C/EBPalpha as a master regulator of airway epithelial maturation and suggest that the loss of C/EBPalpha could also be an important event in the multistep process of lung tumorigenesis. Furthermore, this study indicates that exploring the C/EBPalpha pathway might have therapeutic benefits for patients with respiratory distress syndromes.
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Affiliation(s)
- Daniela S Bassères
- Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02115, USA
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10
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McGee-Estrada K, Fan H. In vivo and in vitro analysis of factor binding sites in Jaagsiekte sheep retrovirus long terminal repeat enhancer sequences: roles of HNF-3, NF-I, and C/EBP for activity in lung epithelial cells. J Virol 2006; 80:332-41. [PMID: 16352558 PMCID: PMC1317537 DOI: 10.1128/jvi.80.1.332-341.2006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Accepted: 10/09/2005] [Indexed: 11/20/2022] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) is the causative agent of ovine pulmonary adenocarcinoma, a contagious lung cancer of sheep that arises from type II pneumocytes and Clara cells of the lung epithelium. Studies of the tropism of this virus have been hindered by the lack of an efficient system for viral replication in tissue culture. To map regulatory regions important for transcriptional activation, an in vivo footprinting method that couples dimethyl sulfate treatment and ligation-mediated PCR was performed in murine type II pneumocyte-derived MLE-15 cells infected with a chimeric Moloney murine leukemia virus driven by the JSRV enhancers (DeltaMo+JS Mo-MuLV). In vivo footprints were found in the JSRV enhancers in two regions previously shown to be important for JSRV long terminal repeat (LTR) activity: a binding site for the lung-specific transcription factor HNF-3beta and an E-box element in the distal enhancer adjacent to an NF-kappaB-like binding site. In addition, in vivo footprints were detected in two downstream motifs likely to bind C/EBP and NF-I. Mutational analysis of a JSRV LTR reporter construct (pJS21luc) revealed that the C/EBP binding site is critical for LTR activity, while the putative NF-I binding element is less important; elimination of these sites resulted in 70% and 40% drops in LTR activity, respectively. Electrophoretic mobility shift assays using nuclear extracts from MLE-15 murine Clara cell-derived mtCC1-2 cells with probes corresponding to the NF-I or C/EBP sites revealed several complexes. Antiserum directed against NF-IA, C/EBPalpha, or C/EBPbeta supershifted the corresponding protein-DNA complexes, indicating that these isoforms, which are also important for the expression of several cellular lung-specific genes, may be important for JSRV expression in lung epithelial cells.
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11
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Halmos B, Bassères DS, Monti S, D'Aló F, Dayaram T, Ferenczi K, Wouters BJ, Huettner CS, Golub TR, Tenen DG. A Transcriptional Profiling Study of CCAAT/Enhancer Binding Protein Targets Identifies Hepatocyte Nuclear Factor 3β as a Novel Tumor Suppressor in Lung Cancer. Cancer Res 2004; 64:4137-47. [PMID: 15205324 DOI: 10.1158/0008-5472.can-03-4052] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We showed previously that CCAAT/enhancer binding protein alpha (C/EBP alpha), a tissue-specific transcription factor, is a candidate tumor suppressor in lung cancer. In the present study, we have performed a transcriptional profiling study of C/EBP alpha target genes using an inducible cell line system. This study led to the identification of hepatocyte nuclear factor 3beta (HNF3 beta), a transcription factor known to play a role in airway differentiation, as a downstream target of C/EBP alpha. We found down-regulation of HNF3 beta expression in a large proportion of lung cancer cell lines examined and identified two novel mutants of HNF3 beta, as well as hypermethylation of the HNF3 beta promoter. We also developed a tetracycline-inducible cell line model to study the cellular consequences of HNF3 beta expression. Conditional expression of HNF3 beta led to significant growth reduction, proliferation arrest, apoptosis, and loss of clonogenic ability, suggesting additionally that HNF3 beta is a novel tumor suppressor in lung cancer. This is the first study to show genetic abnormalities of lung-specific differentiation pathways in the development of lung cancer.
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Affiliation(s)
- Balazs Halmos
- Division of Hematology/Oncology, Beth Israel Deaconess Medical Center, Boston, USA
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12
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Zhang F, Pan T, Nielsen LD, Mason RJ. Lipogenesis in fetal rat lung: importance of C/EBPalpha, SREBP-1c, and stearoyl-CoA desaturase. Am J Respir Cell Mol Biol 2004; 30:174-83. [PMID: 12896875 DOI: 10.1165/rcmb.2003-0235oc] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Alveolar type II cells increase lipogenesis and convert glycogen into the phospholipids of surfactant in the late term fetal lung. Recent studies suggest that CCAAT/enhancing-binding protein (C/EBP) isoforms and sterol regulatory element binding protein (SREBP)-1c regulate fatty acid synthesis in adult type II cells in vitro. To define the temporal relationships and enzymes involved in lipogenesis in fetal rat lung, the mRNA levels of selected transcription factors and enzymes were determined. There was an increase in the mRNA levels of C/EBPalpha, C/EBPbeta, C/EBPdelta, peroxisomal proliferator-activated receptor gamma (PPARgamma), and SREBP-1c, but not SREBP-1a or SREBP-2 from fetal Days 19-21. There was also an increase in the mRNA levels of fatty acid synthase, stearoyl-CoA desaturase 1 (SCD-1), fatty acid translocase, glycerol-3-P acyl transferase, and phosphatidate cytidylyltransferase. By in situ hybridization, there was detectible expression of fatty acid synthase, SCD-1, and C/EBPalpha along the alveolar septae with the same distribution pattern as surfactant protein-C, whereas PPARgamma expression appeared to be restricted to macrophages. Regulation of lipogenesis at the mRNA level is predominately on enzymes of fatty acid synthesis and appears to be regulated by C/EBPalpha and SREBP-1c. SCD-1 and phosphatidate cytidylyltransferase are important components of the lipogenic response in the fetal lung that have not been recognized previously.
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Affiliation(s)
- Feijie Zhang
- National Jewish Medical and Research Center, Denver, CO 80206, USA
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Barlier-Mur AM, Chailley-Heu B, Pinteur C, Henrion-Caude A, Delacourt C, Bourbon JR. Maturational factors modulate transcription factors CCAAT/enhancer-binding proteins alpha, beta, delta, and peroxisome proliferator-activated receptor-gamma in fetal rat lung epithelial cells. Am J Respir Cell Mol Biol 2003; 29:620-6. [PMID: 14568882 DOI: 10.1165/rcmb.4912] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Previous investigations have evidenced the importance of CCAAT/enhancer-binding proteins (C/EBPs) and peroxisome proliferator-activated receptor (PPAR)gamma for lung development, especially for alveolar type II cells (ATII). This prompted us to explore whether ATII maturation-promoting mediators controlled their expression in isolated ATII. In whole rat lung, C/EBPalpha, beta, delta, and PPARgamma mRNAs increased 3-5 times between gestational day 18 and term (Day 22), dropped around birth, then reincreased. C/EBPbeta and delta, but not PPARgamma, displayed similar profile in isolated ATII; C/EBPalpha transcript disappeared and the protein became hardly detectable in isolated cells. In cultured ATII, dexamethasone increased C/EBPbeta and PPARgamma mRNAs 2-4 times, and cyclic AMP increased C/EBPbeta and delta mRNAs approximately 1.5 times. Whereas retinoic acid increased C/EBPbeta and PPARgamma mRNAs 1.5 times in ATII in vitro, vitamin-A deficiency strongly decreased fetal lung C/EBPalpha, beta, and PPARgamma transcripts in vivo. C/EBPbeta, delta, and PPARgamma mRNAs were also increased in vitro by epidermal growth factor and keratinocyte growth factor, whereas they were unchanged by the maturation inhibitor transforming growth factor-beta. C/EBPalpha expression was not reinduced by any mediator. Changes in transcripts were reflected in protein levels analyzed through Western blotting. These results argue for a role of these factors in ATII functional maturation, and indicate a multifactorial control of their ontogeny.
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Affiliation(s)
- Anne-Marie Barlier-Mur
- Inserm U 492, Faculté de Médecine, 8 rue du Général Sarrail, 94010 Créteil cedex, France
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14
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Cassel TN, Nord M. C/EBP transcription factors in the lung epithelium. Am J Physiol Lung Cell Mol Physiol 2003; 285:L773-81. [PMID: 12959923 DOI: 10.1152/ajplung.00023.2003] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During recent years, the biological roles of CCAAT/enhancer binding proteins (C/EBPs) in the lung have started to be uncovered. C/EBPs form a family within the basic region-leucine zipper class of transcription factors. In the lung epithelium C/EBPalpha, -beta, and -delta are expressed. Lung-specific target genes for these transcription factors include the surfactant proteins A and D, the Clara cell secretory protein, and the P450 enzyme CYP2B1. As more information is gathered, a picture is emerging in which C/EBPalpha has a role in regulating proliferation as well as differentiation-dependent gene expression, whereas C/EBPbeta and -delta, in addition to a partly overlapping role in regulating expression of differentiation markers, also seem to be involved in responses to injury and hormones.
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Affiliation(s)
- Tobias N Cassel
- Dept. of Medical Nutrition, Karolinska Institutet, Novum, Huddinge Univ. Hospital, SE 141 86 Huddinge, Sweden
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15
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Mason RJ, Pan T, Edeen KE, Nielsen LD, Zhang F, Longphre M, Eckart MR, Neben S. Keratinocyte growth factor and the transcription factors C/EBP alpha, C/EBP delta, and SREBP-1c regulate fatty acid synthesis in alveolar type II cells. J Clin Invest 2003; 112:244-55. [PMID: 12865412 PMCID: PMC164284 DOI: 10.1172/jci16793] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2002] [Accepted: 05/06/2003] [Indexed: 11/17/2022] Open
Abstract
Strategies to stimulate endogenous surfactant production require a detailed understanding of the regulation of lipogenesis in alveolar type II cells. We developed culture conditions in which keratinocyte growth factor (KGF) stimulates fatty acid and phospholipid synthesis. KGF stimulated acetate incorporation into phosphatidylcholine, disaturated phosphatidylcholine, and phosphatidylglycerol more than 5% rat serum alone. To determine the mRNA levels of lipogenic enzymes and transport proteins, we analyzed gene expression by oligonucleotide microarrays. KGF increased the mRNA levels for fatty acid synthase, stearoyl-CoA desaturase-1 (SCD-1), and epidermal fatty acid-binding protein more than rat serum alone. In addition, KGF increased the mRNA levels of the transcription factors CCAAT/enhancer-binding protein alpha (C/EBPalpha) and C/EBPdelta as well as SREBP-1c (ADD-1), but not PPARgamma. These changes in C/EBPalpha and C/EBPdelta were confirmed by in situ hybridization. SCD-1 was also found to be highly expressed in alveolar type II cells in vivo. Furthermore, KGF increased protein levels of fatty acid synthase, C/EBPalpha, C/EBPdelta, SREBP-1, epidermal fatty acid-binding protein, and SCD. Finally, the liver X receptor agonist T0901317 increased acetate incorporation and SREBP-1 but not SREBP-2 protein levels. In summary, KGF stimulates lipogenesis in type II cells by a coordinated expression of lipogenic enzymes and transport proteins regulated by C/EBP isoforms and SREBP-1c.
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Affiliation(s)
- Robert J Mason
- Department of Medicine, National Jewish Medical and Research Center, Denver, Colorado 80206, USA.
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16
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Reddy SPM, Mossman BT. Role and regulation of activator protein-1 in toxicant-induced responses of the lung. Am J Physiol Lung Cell Mol Physiol 2002; 283:L1161-78. [PMID: 12424143 DOI: 10.1152/ajplung.00140.2002] [Citation(s) in RCA: 108] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Aberrant cell proliferation and differentiation after toxic injury to airway epithelium can lead to the development of various lung diseases including cancer. The activator protein-1 (AP-1) transcription factor, composed of mainly Jun-Jun and Jun-Fos protein dimers, acts as an environmental biosensor to various external toxic stimuli and regulates gene expression involved in various biological processes. Gene disruption studies indicate that the AP-1 family members c-jun, junB, and fra1 are essential for embryonic development, whereas junD, c-fos, and fosB are required for normal postnatal growth. However, broad or target-specific transgenic overexpression of the some of these proteins gives very distinct phenotype(s), including tumor formation. This implies that, although they are required for normal cellular processes, their abnormal activation after toxic injury can lead to the pathogenesis of the lung disease. Consistent with this view, various environmental toxicants and carcinogens differentially regulate Jun and Fos expression in cells of the lung both in vivo and in vitro. Moreover, Jun and Fos proteins distinctly bind to the promoter regions of a wide variety of genes to differentially regulate their expression in epithelial injury, repair, and differentiation. Importantly, lung tumors induced by various carcinogens display a sustained expression of certain AP-1 family members. Therefore a better understanding of the mechanisms of regulation and functional role(s), as well as identification of target genes of members of the AP-1 family in airway epithelial cells, will provide additional insight into toxicant-induced lung diseases. These studies might offer a unique opportunity to use AP-1 family members and transactivation as potential diagnostic markers or drug targets for early detection and/or prevention of various lung diseases.
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Affiliation(s)
- Sekhar P M Reddy
- Department of Environmental Health Sciences and Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University, Baltimore, Maryland 21205, USA.
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17
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Gonzales LW, Angampalli S, Guttentag SH, Beers MF, Feinstein SI, Matlapudi A, Ballard PL. Maintenance of differentiated function of the surfactant system in human fetal lung type II epithelial cells cultured on plastic. PEDIATRIC PATHOLOGY & MOLECULAR MEDICINE 2001; 20:387-412. [PMID: 11552739 DOI: 10.1080/15513810109168622] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
We report a simplified culture system for human fetal lung type II cells that maintains surfactant expression. Type II cells isolated from explant cultures of hormone-treated lungs (18-22 wk gestation) by collagenase + trypsin digestion were cultured on plastic for 4 days in serum-free medium containing dexamethasone (Dex, 10 nM) + 8-bromo-cAMP (0.1 mM + isobutylmethylxanthine (0.1 mM) or were untreated (control). Surfactant protein (SP) mRNAs decreased markedly in control cells between days 1 and 4 of culture, but mRNA levels were high in treated cells on day) 4 (SP-A, SP-B, SP-C, SP-D; 600%, 100%, 85%, 130% of day 0 content, respectively). Dex or cAMP alone increased SP-B, SP-C, and SP-D mRNAs and together had additive effects. The greatest increase in SP-A mRNA occurred with cAMP alone. Treated cells processed pro-SP-B and pro-SP-C proteins to mature forms and had a higher rate of phosphatidylcholine (PC) synthesis (2-fold) and higher saturation of PC (approximately 34% versus 27%) than controls. Only treated cells maintained secretagogue-responsive phospholipid synthesis. By electron microscopy, the treated cells retained lamellar bodies and extensive microvilli. We conclude that Dex and cAMP additively stimulate expression of surfactant components in isolated fetal type II cells, providing a simplified culture system for investigation of surfactant-related, and perhaps other, type II cell functions.
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Affiliation(s)
- L W Gonzales
- Department of Pediatrics, Children's Hospital of Philadelphia, Pennsylvania, USA.
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18
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Abstract
By transducing an apoptotic signal in immune effector cells, Fas has been directly implicated in the control of immunological activity. Expression and functional results, however, have also suggested a role for Fas in regulating cell turnover in specific epithelial populations. To characterize factors responsible for Fas expression in epithelial cells, approximately 3 kb of the 5' flanking region of the mouse Fas gene was isolated. By rapid amplification of cDNA ends and primer extension, transcriptional start sites were identified within 50 bp upstream of the translation start site. Transient transfection of promoter-luciferase constructs in a mouse lung epithelial cell line, MLE-15, localized promoter activity to the first 77 bp of upstream sequence. By using a 60 bp DNA probe (-18 to -77) in electrophoretic mobility-shift assays, three shifted complexes were found. Incubation with excess cold Sp1 oligonucleotide or an anti-Sp3 antibody inhibited complex formation. Site-directed mutagenesis of the Sp1 site resulted in 60-70% loss of promoter activity. In Drosophila SL-2 cells, promoter activity was markedly increased by co-transfection of an Sp3 expression construct. These results show that the Sp3 protein is involved in regulating Fas gene expression in lung epithelial cells.
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Affiliation(s)
- H Pang
- The Pulmonary Center, Boston University School of Medicine, 80 E. Concord Street, Boston, MA 02118, USA
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Iwama A, Zhang P, Darlington GJ, McKercher SR, Maki R, Tenen DG. Use of RDA analysis of knockout mice to identify myeloid genes regulated in vivo by PU.1 and C/EBPalpha. Nucleic Acids Res 1998; 26:3034-43. [PMID: 9611252 PMCID: PMC147647 DOI: 10.1093/nar/26.12.3034] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
PU.1 and C/EBPalpha are transcription factors essential for normal myeloid development. Loss-of-function mutation of PU.1 leads to an absolute block in monocyte/macrophage development and abnormal granulocytic development while that of C/EBPalpha causes a selective block in neutrophilic differentiation. In order to understand these phenotypes, we studied the role of PU.1 and C/EBPalpha in the regulation of myeloid target genes in vivo . Northern blot analysis revealed that mRNAs encoding receptors for M-CSF, G-CSF and GM-CSF, were expressed at low levels in PU.1(-/-) fetal liver compared with wild type. To identify additional myeloid genes regulated by PU.1 and C/EBPalpha, we performed representational difference analysis (RDA), a PCR-based subtractive hybridization using fetal livers from wild type and PU.1 or C/EBPalpha knockout mice. By introducing a new modification of RDA, that of tissue-specific gene suppression, we could selectively identify a set of differentially expressed genes specific to myeloid cells. Differentially expressed genes included both primary and secondary granule protein genes. In addition, eight novel genes were identified that were upregulated in expression during myeloid differentiation. These methods provide a general strategy for elucidating the genes affected in murine knockout models.
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Affiliation(s)
- A Iwama
- Hematology/Oncology Division and Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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Breed DR, Margraf LR, Alcorn JL, Mendelson CR. Transcription factor C/EBPdelta in fetal lung: developmental regulation and effects of cyclic adenosine 3',5'-monophosphate and glucocorticoids. Endocrinology 1997; 138:5527-34. [PMID: 9389540 DOI: 10.1210/endo.138.12.5637] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Pulmonary surfactant is a developmentally and hormonally regulated lipoprotein synthesized exclusively in alveolar type II cells. Surfactant protein-A (SP-A) gene transcription in human fetal lung in culture is stimulated by glucocorticoids and cAMP; cAMP also enhances the rate of type II cell differentiation. The CCAAT/enhancer-binding protein (C/EBP) family of transcription factors serves an important role in the regulation of genes involved in energy metabolism, lipid biosynthesis, and cellular differentiation. The gene encoding C/EBPdelta, which is induced by glucocorticoids during the early phases of adipocyte differentiation, is expressed at relatively high levels in lung compared with other tissues. In the present study we have analyzed developmental changes in C/EBPdelta messenger RNA levels in fetal rabbit lung as well as changes in the levels of immunoreactive C/EBPdelta in human fetal lung during differentiation in organ culture and after treatment with cAMP and glucocorticoids. We observed that C/EBPdelta messenger RNA is detectable in fetal rabbit lung on day 19 of gestation and is increased approximately 3.7-fold to maximum levels on day 28 of gestation, the time when SP-A gene transcription increases to maximum levels. Immunohistochemical analysis of C/EBPdelta in midgestation human fetal lung before culture revealed trace nuclear staining in epithelial and occasional stromal cells. After 12 h of organ culture in serum-free medium, nuclear staining of C/EBPdelta was markedly increased in epithelial cells lining the prealveolar ducts of the human fetal lung tissue. By immunoblot analysis, it was found that C/EBPdelta levels were induced rapidly during organ culture in control medium and were increased further by treatment with dexamethasone and (Bt)2cAMP. C/EBPdelta levels were maximally induced during the first 24 h of culture and declined thereafter; after 72 h of incubation in control or cAMP-containing medium, C/EBPdelta was reduced markedly. By contrast, in fetal lung tissues incubated in medium containing dexamethasone or dexamethasone plus (Bt)2cAMP, the decline in C/EBPdelta was more modest, so that levels remained elevated throughout the 96-h culture period. Our findings that C/EBPdelta is localized primarily to alveolar epithelial cells, rapidly induced during differentiation of human fetal lung in culture, and increased by cAMP and glucocorticoids suggest a possible role in the regulation of type II cell differentiation and in the synthesis of surfactant phospholipids and proteins.
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Affiliation(s)
- D R Breed
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235, USA
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