14 results on '"Ng-Blichfeldt JP"'
Search Results
2. Identification of a core transcriptional program driving the human renal mesenchymal-to-epithelial transition.
- Author
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Ng-Blichfeldt JP, Stewart BJ, Clatworthy MR, Williams JM, and Röper K
- Subjects
- Humans, Mice, Animals, Cell Differentiation genetics, Transcription Factors metabolism, Signal Transduction, Epithelial-Mesenchymal Transition, Kidney metabolism, Nephrons
- Abstract
During kidney development, nephron epithelia arise de novo from fate-committed mesenchymal progenitors through a mesenchymal-to-epithelial transition (MET). Downstream of fate specification, transcriptional mechanisms that drive establishment of epithelial morphology are poorly understood. We used human iPSC-derived renal organoids, which recapitulate nephrogenesis, to investigate mechanisms controlling renal MET. Multi-ome profiling via snRNA-seq and ATAC-seq of organoids identified dynamic changes in gene expression and chromatin accessibility driven by activators and repressors throughout MET. CRISPR interference identified that paired box 8 (PAX8) is essential for initiation of MET in human renal organoids, contrary to in vivo mouse studies, likely by activating a cell-adhesion program. While Wnt/β-catenin signaling specifies nephron fate, we find that it must be attenuated to allow hepatocyte nuclear factor 1-beta (HNF1B) and TEA-domain (TEAD) transcription factors to drive completion of MET. These results identify the interplay between fate commitment and morphogenesis in the developing human kidney, with implications for understanding both developmental kidney diseases and aberrant epithelial plasticity following adult renal tubular injury., Competing Interests: Declaration of interests J.M.W. is an employee and stockholder of AstraZeneca., (Copyright © 2024 MRC Laboratory of Molecular Biology. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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3. Cigarette smoke restricts the ability of mesenchymal cells to support lung epithelial organoid formation.
- Author
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Khedoe PPSJ, van Schadewijk WAAM, Schwiening M, Ng-Blichfeldt JP, Marciniak SJ, Stolk J, Gosens R, and Hiemstra PS
- Abstract
Adequate lung epithelial repair relies on supportive interactions within the epithelial niche, including interactions with WNT-responsive fibroblasts. In fibroblasts from patients with chronic obstructive pulmonary disease (COPD) or upon in vitro cigarette smoke exposure, Wnt/β-catenin signalling is distorted, which may affect interactions between epithelial cells and fibroblasts resulting in inadequate lung repair. We hypothesized that cigarette smoke (CS), the main risk factor for COPD, interferes with Wnt/β-catenin signalling in fibroblasts through induction of cellular stress responses, including oxidative- and endoplasmic reticulum (ER) stress, and thereby alters epithelial repair support potential. Therefore, we assessed the effect of CS-exposure and the ER stress inducer Thapsigargin (Tg) on Wnt/β-catenin signalling activation in MRC-5 fibroblasts, and on their ability to support lung epithelial organoid formation. Exposure of MRC-5 cells for 15 min with 5 AU/mL CS extract (CSE), and subsequent 6 h incubation induced oxidative stress ( HMOX1 ). Whereas stimulation with 100 nM Tg increased markers of both the integrated stress response (ISR - GADD34 / PPP1R15A , CHOP ) and the unfolded protein response (UPR - XBP1spl , GADD34/PPP1R15A , CHOP and HSPA5/BIP ), CSE only induced GADD34 / PPP1R15A expression. Strikingly, although treatment of MRC-5 cells with the Wnt activator CHIR99021 upregulated the Wnt/β-catenin target gene AXIN2, this response was diminished upon CSE or Tg pre-exposure, which was confirmed using a Wnt-reporter. Furthermore, pre-exposure of MRC-5 cells to CSE or Tg, restricted their ability to support organoid formation upon co-culture with murine pulmonary EpCam
+ cells in Matrigel at day 14. This restriction was alleviated by pre-treatment with CHIR99021. We conclude that exposure of MRC-5 cells to CSE increases oxidative stress, GADD34/PPP1R15A expression and impairs their ability to support organoid formation. This inhibitory effect may be restored by activating the Wnt/β-catenin signalling pathway., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer GT declared a past co-authorship with the authors RG to the handling Editor, (Copyright © 2023 Khedoe, van Schadewijk, Schwiening, Ng-Blichtfeldt, Marciniak, Stolk, Gosens and Hiemstra.)- Published
- 2023
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4. Rejuvenating old lungs: Ain't no tonic like a drop of retinoic.
- Author
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Gosens R and Ng-Blichfeldt JP
- Subjects
- Humans, Lung
- Abstract
Competing Interests: Competing interests: RG has received research funding, through the institution, from Aquilo BV, from Boehringer Ingelheim, from Chiesi, and from Sanofi-Aventis.
- Published
- 2021
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5. Rho-Kinase 1/2 Inhibition Prevents Transforming Growth Factor-β-Induced Effects on Pulmonary Remodeling and Repair.
- Author
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Wu X, Verschut V, Woest ME, Ng-Blichfeldt JP, Matias A, Villetti G, Accetta A, Facchinetti F, Gosens R, and Kistemaker LEM
- Abstract
Transforming growth factor (TGF)-β-induced myofibroblast transformation and alterations in mesenchymal-epithelial interactions contribute to chronic lung diseases such as chronic obstructive pulmonary disease (COPD), asthma and pulmonary fibrosis. Rho-associated coiled-coil-forming protein kinase (ROCK) consists as two isoforms, ROCK1 and ROCK2, and both are playing critical roles in many cellular responses to injury. In this study, we aimed to elucidate the differential role of ROCK isoforms on TGF-β signaling in lung fibrosis and repair. For this purpose, we tested the effect of a non-selective ROCK 1 and 2 inhibitor (compound 31) and a selective ROCK2 inhibitor (compound A11) in inhibiting TGF-β-induced remodeling in lung fibroblasts and slices; and dysfunctional epithelial-progenitor interactions in lung organoids. Here, we demonstrated that the inhibition of ROCK1/2 with compound 31 represses TGF-β-driven actin remodeling as well as extracellular matrix deposition in lung fibroblasts and PCLS, whereas selective ROCK2 inhibition with compound A11 did not. Furthermore, the TGF-β induced inhibition of organoid formation was functionally restored in a concentration-dependent manner by both dual ROCK 1 and 2 inhibition and selective ROCK2 inhibition. We conclude that dual pharmacological inhibition of ROCK 1 and 2 counteracts TGF-β induced effects on remodeling and alveolar epithelial progenitor function, suggesting this to be a promising therapeutic approach for respiratory diseases associated with fibrosis and defective lung repair., Competing Interests: Author GV, AA and FF are employees of Chiesi Farmaceutici SpA. Author LK and RG have received funding for research and lecture fees from Boehringer Ingelheim. Author MW, VV and LK were employed by the company Aquilo BV. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Wu, Verschut, Woest, Ng-Blichfeldt, Matias, Villetti, Accetta, Facchinetti, Gosens and Kistemaker.)
- Published
- 2021
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6. Mesenchymal-to-Epithelial Transitions in Development and Cancer.
- Author
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Ng-Blichfeldt JP and Röper K
- Subjects
- Animals, Homeostasis genetics, Humans, Phenotype, Transcription Factors genetics, Embryonic Development genetics, Epithelial-Mesenchymal Transition genetics, MicroRNAs genetics, Neoplasms genetics
- Abstract
The evolutionary emergence of the mesenchymal phenotype greatly increased the complexity of tissue architecture and composition in early Metazoan species. At the molecular level, an epithelial-to-mesenchymal transition (EMT) was permitted by the innovation of specific transcription factors whose expression is sufficient to repress the epithelial transcriptional program. The reverse process, mesenchymal-to-epithelial transition (MET), involves direct inhibition of EMT transcription factors by numerous mechanisms including tissue-specific MET-inducing transcription factors (MET-TFs), micro-RNAs, and changes to cell and tissue architecture, thus providing an elegant solution to the need for tight temporal and spatial control over EMT and MET events during development and adult tissue homeostasis.
- Published
- 2021
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7. Wnt/β-catenin signaling is critical for regenerative potential of distal lung epithelial progenitor cells in homeostasis and emphysema.
- Author
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Hu Y, Ng-Blichfeldt JP, Ota C, Ciminieri C, Ren W, Hiemstra PS, Stolk J, Gosens R, and Königshoff M
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- Animals, Emphysema pathology, Humans, Mice, Wnt Signaling Pathway, Emphysema genetics, Homeostasis physiology, Stem Cells metabolism, beta Catenin metabolism
- Abstract
Wnt/β-catenin signaling regulates progenitor cell fate decisions during lung development and in various adult tissues. Ectopic activation of Wnt/β-catenin signaling promotes tissue repair in emphysema, a devastating lung disease with progressive loss of parenchymal lung tissue. The identity of Wnt/β-catenin responsive progenitor cells and the potential impact of Wnt/β-catenin signaling on adult distal lung epithelial progenitor cell function in emphysema are poorly understood. Here, we used TCF/Lef:H2B/GFP reporter mice to investigate the role of Wnt/β-catenin signaling in lung organoid formation. We identified an organoid-forming adult distal lung epithelial progenitor cell population characterized by a low Wnt/β-catenin activity, which was enriched in club and alveolar epithelial type (AT)II cells. Endogenous Wnt/β-catenin activity was required for the initiation of multiple subtypes of distal lung organoids derived from the Wnt
low epithelial progenitors. Further ectopic Wnt/β-catenin activation specifically led to an increase in alveolar organoid number; however, the subsequent proliferation of alveolar epithelial cells in the organoids did not require constitutive Wnt/β-catenin signaling. Distal lung epithelial progenitor cells derived from the mouse model of elastase-induced emphysema exhibited reduced organoid forming capacity. This was rescued by Wnt/β-catenin signal activation, which largely increased the number of alveolar organoids. Together, our study reveals a novel mechanism of lung epithelial progenitor cell activation in homeostasis and emphysema., (©2020 The Authors. Stem Cells published by Wiley Periodicals LLC on behalf of AlphaMed Press 2020.)- Published
- 2020
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8. Divergent effects of Wnt5b on IL-3- and GM-CSF-induced myeloid differentiation.
- Author
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de Rezende MM, Ng-Blichfeldt JP, Justo GZ, Paredes-Gamero EJ, and Gosens R
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- Animals, Mice, Inbred C57BL, Myeloid Cells drug effects, Myeloid Cells metabolism, Stem Cells cytology, Stem Cells drug effects, Cell Differentiation drug effects, Granulocyte-Macrophage Colony-Stimulating Factor pharmacology, Interleukin-3 pharmacology, Myeloid Cells cytology, Wnt Proteins pharmacology
- Abstract
The multiple specialized cell types of the hematopoietic system originate from differentiation of hematopoietic stem cells and progenitors (HSPC), which can generate both lymphoid and myeloid lineages. The myeloid lineage is preferentially maintained during ageing, but the mechanisms that contribute to this process are incompletely understood. Here, we studied the roles of Wnt5a and Wnt5b, ligands that have previously been linked to hematopoietic stem cell ageing and that are abundantly expressed by both hematopoietic progenitors and bone-marrow derived niche cells. Whereas Wnt5a had no major effects on primitive cell differentiation, Wnt5b had profound and divergent effects on cytokine-induced myeloid differentiation. Remarkably, while IL-3-mediated myeloid differentiation was largely repressed by Wnt5b, GM-CSF-induced myeloid differentiation was augmented. Furthermore, in the presence of IL-3, Wnt5b enhanced HSPC self-renewal, whereas in the presence of GM-CSF, Wnt5b accelerated differentiation, leading to progenitor cell exhaustion. Our results highlight discrepancies between IL-3 and GM-CSF, and reveal novel effects of Wnt5b on the hematopoietic system., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2020
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9. Mesenchymal WNT-5A/5B Signaling Represses Lung Alveolar Epithelial Progenitors.
- Author
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Wu X, van Dijk EM, Ng-Blichfeldt JP, Bos IST, Ciminieri C, Königshoff M, Kistemaker LEM, and Gosens R
- Subjects
- Alveolar Epithelial Cells metabolism, Animals, Cell Differentiation, Cell Line, Cell Proliferation, Coculture Techniques, Female, Fibroblasts cytology, Humans, Male, Mice, Organoids metabolism, Stem Cells cytology, Stem Cells metabolism, Up-Regulation, Wnt Signaling Pathway, Aging metabolism, Alveolar Epithelial Cells cytology, Organoids cytology, Pulmonary Disease, Chronic Obstructive metabolism, Wnt Proteins metabolism, Wnt-5a Protein metabolism
- Abstract
Chronic obstructive pulmonary disease (COPD) represents a worldwide concern with high morbidity and mortality, and is believed to be associated with accelerated ageing of the lung. Alveolar abnormalities leading to emphysema are a key characteristic of COPD. Pulmonary alveolar epithelial type 2 cells (AT2) produce surfactant and function as progenitors for type 1 cells. Increasing evidence shows elevated WNT-5A/B expression in ageing and in COPD that may contribute to the disease process. However, supportive roles for WNT-5A/B in lung regeneration were also reported in different studies. Thus, we explored the role of WNT-5A/B on alveolar epithelial progenitors (AEPs) in more detail. We established a Precision-Cut-Lung Slices (PCLS) model and a lung organoid model by co-culturing epithelial cells (EpCAM
+ /CD45- /CD31- ) with fibroblasts in matrigel in vitro to study the impact of WNT-5A and WNT-5B. Our results show that WNT-5A and WNT-5B repress the growth of epithelial progenitors with WNT-5B preferentially restraining the growth and differentiation of alveolar epithelial progenitors. We provide evidence that both WNT-5A and WNT-5B negatively regulate the canonical WNT signaling pathway in alveolar epithelium. Taken together, these findings reveal the functional impact of WNT-5A/5B signaling on alveolar epithelial progenitors in the lung, which may contribute to defective alveolar repair in COPD., Competing Interests: The authors declare no conflict of interest.- Published
- 2019
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10. Regenerative pharmacology for COPD: breathing new life into old lungs.
- Author
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Ng-Blichfeldt JP, Gosens R, Dean C, Griffiths M, and Hind M
- Subjects
- Animals, Clinical Trials as Topic, Humans, Lung physiology, Pulmonary Disease, Chronic Obstructive drug therapy, Pulmonary Disease, Chronic Obstructive physiopathology, Regeneration physiology
- Abstract
Chronic obstructive pulmonary disease (COPD) is a major global health concern with few effective treatments. Widespread destruction of alveolar tissue contributes to impaired gas exchange in severe COPD, and recent radiological evidence suggests that destruction of small airways is a major contributor to increased peripheral airway resistance in disease. This important finding might in part explain the failure of conventional anti-inflammatory treatments to restore lung function even in patients with mild disease. There is a clear need for alternative pharmacological strategies for patients with COPD/emphysema. Proposed regenerative strategies such as cell therapy and tissue engineering are hampered by poor availability of exogenous stem cells, discouraging trial results, and risks and cost associated with surgery. An alternative therapeutic approach is augmentation of lung regeneration and/or repair by biologically active factors, which have potential to be employed on a large scale. In favour of this strategy, the healthy adult lung is known to possess a remarkable endogenous regenerative capacity. Numerous preclinical studies have shown induction of regeneration in animal models of COPD/emphysema. Here, we argue that given the widespread and irreversible nature of COPD, serious consideration of regenerative pharmacology is necessary. However, for this approach to be feasible, a better understanding of the cell-specific molecular control of regeneration, the regenerative potential of the human lung and regenerative competencies of patients with COPD are required., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)
- Published
- 2019
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11. TGF-β activation impairs fibroblast ability to support adult lung epithelial progenitor cell organoid formation.
- Author
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Ng-Blichfeldt JP, de Jong T, Kortekaas RK, Wu X, Lindner M, Guryev V, Hiemstra PS, Stolk J, Königshoff M, and Gosens R
- Subjects
- Adult Stem Cells drug effects, Adult Stem Cells pathology, Aged, Animals, Cell Communication drug effects, Cell Differentiation drug effects, Coculture Techniques, Epithelial Cell Adhesion Molecule genetics, Epithelial Cell Adhesion Molecule metabolism, Epithelial Cells drug effects, Epithelial Cells pathology, Female, Fibroblast Growth Factor 7 pharmacology, Fibroblasts pathology, Gene Expression Profiling, Gene Expression Regulation, Hepatocyte Growth Factor pharmacology, Humans, Lung metabolism, Lung pathology, Male, Mice, Mice, Inbred C57BL, Middle Aged, Myofibroblasts drug effects, Myofibroblasts metabolism, Myofibroblasts pathology, Organoids drug effects, Organoids pathology, Pulmonary Disease, Chronic Obstructive metabolism, Pulmonary Disease, Chronic Obstructive pathology, Pyridines pharmacology, Pyrimidines pharmacology, Transforming Growth Factor beta pharmacology, Wnt Proteins genetics, Wnt Proteins metabolism, Wnt Signaling Pathway, beta Catenin genetics, beta Catenin metabolism, Adult Stem Cells metabolism, Epithelial Cells metabolism, Fibroblasts metabolism, Organoids metabolism, Pulmonary Disease, Chronic Obstructive genetics, Transforming Growth Factor beta metabolism
- Abstract
Transforming growth factor-β (TGF-β)-induced fibroblast-to-myofibroblast differentiation contributes to remodeling in chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis, but whether this impacts the ability of fibroblasts to support lung epithelial repair remains little explored. We pretreated human lung fibroblasts [primary (phFB) or MRC5 cells] with recombinant human TGF-β to induce myofibroblast differentiation, then cocultured them with adult mouse lung epithelial cell adhesion molecule-positive cells (EpCAM
+ ) to investigate their capacity to support epithelial organoid formation in vitro. While control phFB and MRC5 lung fibroblasts supported organoid formation of mouse EpCAM+ cells, TGF-β pretreatment of both phFB and MRC5 impaired organoid-supporting ability. We performed RNA sequencing of TGF-β-treated phFB, which revealed altered expression of key Wnt signaling pathway components and Wnt/β-catenin target genes, and modulated expression of secreted factors involved in mesenchymal-epithelial signaling. TGF-β profoundly skewed the transcriptional program induced by the Wnt/β-catenin activator CHIR99021. Supplementing organoid culture media recombinant hepatocyte growth factor or fibroblast growth factor 7 promoted organoid formation when using TGF-β pretreated fibroblasts. In conclusion, TGF-β-induced myofibroblast differentiation results in Wnt/β-catenin pathway skewing and impairs fibroblast ability to support epithelial repair likely through multiple mechanisms, including modulation of secreted growth factors.- Published
- 2019
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12. Retinoic acid signaling balances adult distal lung epithelial progenitor cell growth and differentiation.
- Author
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Ng-Blichfeldt JP, Schrik A, Kortekaas RK, Noordhoek JA, Heijink IH, Hiemstra PS, Stolk J, Königshoff M, and Gosens R
- Subjects
- Animals, Cell Line, Cell Proliferation, Fibroblast Growth Factors metabolism, Gene Expression Regulation, Histone Deacetylases metabolism, Humans, Mice, Pulmonary Disease, Chronic Obstructive etiology, Pulmonary Disease, Chronic Obstructive metabolism, Pulmonary Disease, Chronic Obstructive physiopathology, Pulmonary Disease, Chronic Obstructive therapy, Regeneration, Cell Differentiation, Respiratory Mucosa cytology, Respiratory Mucosa metabolism, Signal Transduction, Stem Cells cytology, Stem Cells metabolism, Tretinoin metabolism
- Abstract
Background: Despite compelling data describing pro-regenerative effects of all-trans retinoic acid (ATRA) in pre-clinical models of chronic obstructive pulmonary disease (COPD), clinical trials using retinoids for emphysema patients have failed. Crucial information about the specific role of RA signaling in adult rodent and human lung epithelial progenitor cells is largely missing., Methods: Adult lung organoid cultures were generated from isolated primary mouse and human lung epithelial cells, and incubated with pharmacological pathway modulators and recombinant proteins. Organoid number and size were measured, and differentiation was assessed with quantitative immunofluorescence and gene expression analyses., Findings: We unexpectedly found that ATRA decreased lung organoid size, whereas RA pathway inhibition increased mouse and human lung organoid size. RA pathway inhibition stimulated mouse lung epithelial proliferation via YAP pathway activation and epithelial-mesenchymal FGF signaling, while concomitantly suppressing alveolar and airway differentiation. HDAC inhibition rescued differentiation in growth-augmented lung organoids., Interpretation: In contrast to prevailing notions, our study suggests that regenerative pharmacology using transient RA pathway inhibition followed by HDAC inhibition might hold promise to promote lung epithelial regeneration in diseased adult lung tissue. FUND: This project is funded by the Lung Foundation Netherlands (Longfonds) grant 6.1.14.009 (RG, MK, JS, PSH) and W2/W3 Professorship Award by the Helmholtz Association, Berlin, Germany (MK)., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2018
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13. Dynamic expression of HOPX in alveolar epithelial cells reflects injury and repair during the progression of pulmonary fibrosis.
- Author
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Ota C, Ng-Blichfeldt JP, Korfei M, Alsafadi HN, Lehmann M, Skronska-Wasek W, M De Santis M, Guenther A, Wagner DE, and Königshoff M
- Subjects
- Alveolar Epithelial Cells pathology, Animals, Bleomycin toxicity, Cell Line, Cell Transdifferentiation, Disease Models, Animal, Disease Progression, Female, Homeodomain Proteins genetics, Humans, Idiopathic Pulmonary Fibrosis pathology, Intercellular Signaling Peptides and Proteins metabolism, Lung physiology, Mice, Mice, Inbred C57BL, Pulmonary Fibrosis chemically induced, Pulmonary Fibrosis metabolism, Pulmonary Fibrosis pathology, Pulmonary Surfactant-Associated Protein C, RNA Interference, RNA, Small Interfering genetics, Regeneration genetics, Transfection, Tumor Suppressor Proteins genetics, Alveolar Epithelial Cells metabolism, Homeodomain Proteins biosynthesis, Idiopathic Pulmonary Fibrosis metabolism, Pulmonary Alveoli pathology, Tumor Suppressor Proteins biosynthesis
- Abstract
Mechanisms of injury and repair in alveolar epithelial cells (AECs) are critically involved in the progression of various lung diseases including idiopathic pulmonary fibrosis (IPF). Homeobox only protein x (HOPX) contributes to the formation of distal lung during development. In adult lung, alveolar epithelial type (AT) I cells express HOPX and lineage-labeled Hopx+ cells give rise to both ATI and ATII cells after pneumonectomy. However, the cell function of HOPX-expressing cells in adult fibrotic lung diseases has not been investigated. In this study, we have established a flow cytometry-based method to evaluate HOPX-expressing cells in the lung. HOPX expression in cultured ATII cells increased over culture time, which was accompanied by a decrease of proSP-C, an ATII marker. Moreover, HOPX expression was increased in AECs from bleomycin-instilled mouse lungs in vivo. Small interfering RNA-based knockdown of Hopx resulted in suppressing ATII-ATI trans-differentiation and activating cellular proliferation in vitro. In IPF lungs, HOPX expression was decreased in whole lungs and significantly correlated to a decline in lung function and progression of IPF. In conclusion, HOPX is upregulated during early alveolar injury and repair process in the lung. Decreased HOPX expression might contribute to failed regenerative processes in end-stage IPF lungs.
- Published
- 2018
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14. Deficient retinoid-driven angiogenesis may contribute to failure of adult human lung regeneration in emphysema.
- Author
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Ng-Blichfeldt JP, Alçada J, Montero MA, Dean CH, Griesenbach U, Griffiths MJ, and Hind M
- Subjects
- Aged, Alveolar Epithelial Cells drug effects, Alveolar Epithelial Cells physiology, Cell Line, Cells, Cultured, Female, Gene Expression Regulation drug effects, Humans, Lung metabolism, Male, Middle Aged, Neovascularization, Physiologic physiology, Pulmonary Alveoli pathology, Pulmonary Emphysema pathology, RNA, Messenger genetics, Receptors, Retinoic Acid metabolism, Regeneration drug effects, Signal Transduction drug effects, Signal Transduction physiology, Vascular Endothelial Growth Factor A biosynthesis, Vascular Endothelial Growth Factor A genetics, Vascular Endothelial Growth Factor Receptor-2 biosynthesis, Vascular Endothelial Growth Factor Receptor-2 genetics, Lung physiology, Neovascularization, Physiologic drug effects, Pulmonary Emphysema physiopathology, Regeneration physiology, Tretinoin pharmacology
- Abstract
Background: Molecular pathways that regulate alveolar development and adult repair represent potential therapeutic targets for emphysema. Signalling via retinoic acid (RA), derived from vitamin A, is required for mammalian alveologenesis, and exogenous RA can induce alveolar regeneration in rodents. Little is known about RA signalling in the human lung and its potential role in lung disease., Objectives: To examine regulation of human alveolar epithelial and endothelial repair by RA, and characterise RA signalling in human emphysema., Methods: The role of RA signalling in alveolar epithelial repair was investigated with a scratch assay using an alveolar cell line (A549) and primary human alveolar type 2 (AT2) cells from resected lung, and the role in angiogenesis using a tube formation assay with human lung microvascular endothelial cells (HLMVEC). Localisation of RA synthetic (RALDH-1) and degrading (cytochrome P450 subfamily 26 A1 (CYP26A1)) enzymes in human lung was determined by immunofluorescence. Regulation of RA pathway components was investigated in emphysematous and control human lung tissue by quantitative real-time PCR and Western analysis., Results: RA stimulated HLMVEC angiogenesis in vitro; this was partially reproduced with a RAR-α agonist. RA induced mRNA expression of vascular endothelial growth factor A (VEGFA) and VEGFR2. RA did not modulate AT2 repair. CYP26A1 protein was identified in human lung microvasculature, whereas RALDH-1 partially co-localised with vimentin-positive fibroblasts. CYP26A1 mRNA and protein were increased in emphysema., Conclusions: RA regulates lung microvascular angiogenesis; the endothelium produces CYP26A1 which is increased in emphysema, possibly leading to reduced RA availability. These data highlight a role for RA in maintenance of the human pulmonary microvascular endothelium., Competing Interests: Competing interests: None declared., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.)
- Published
- 2017
- Full Text
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