| 1. |
- Bazigou, Eleni, et al.
(author)
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Integrin-alpha9 is required for fibronectin matrix assembly during lymphatic valve morphogenesis.
- 2009
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In: Developmental Cell. - : Elsevier BV. - 1534-5807 .- 1878-1551. ; 17:2
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Journal article (peer-reviewed)abstract
- Dysfunction of lymphatic valves underlies human lymphedema, yet the process of valve morphogenesis is poorly understood. Here, we show that during embryogenesis, lymphatic valve leaflet formation is initiated by upregulation of integrin-alpha9 expression and deposition of its ligand fibronectin-EIIIA (FN-EIIIA) in the extracellular matrix. Endothelial cell-specific deletion of Itga9 (encoding integrin-alpha9) in mouse embryos results in the development of rudimentary valve leaflets characterized by disorganized FN matrix, short cusps, and retrograde lymphatic flow. Similar morphological and functional defects are observed in mice lacking the EIIIA domain of FN. Mechanistically, we demonstrate that in primary human lymphatic endothelial cells, the integrin-alpha9-EIIIA interaction directly regulates FN fibril assembly, which is essential for the formation of the extracellular matrix core of valve leaflets. Our findings reveal an important role for integrin-alpha9 signaling during lymphatic valve morphogenesis and implicate it as a candidate gene for primary lymphedema caused by valve defects.
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| 2. |
- Cook, David C., et al.
(author)
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Plant biosecurity policy-making modelled on the human immune system: What would it look like?
- 2014
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In: Environmental Science and Policy. - : Elsevier BV. - 1462-9011. ; 41, s. 1-10
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Journal article (peer-reviewed)abstract
- This paper takes inspiration from the field of bio-mimicry to suggest what a plant biosecurity system might look like if it was modelled on the human immune system. We suggest structural and institutional changes to current biosecurity systems that would facilitate adaptive preparation and response policies, focusing particularly on the Australian plant biosecurity system. By improving information exchanges, interpretation and managing overlapping complementary response capabilities of this system, novel policies emerge that increase resilience to harmful weeds, pests and diseases. This is achieved by adding an element of flexibility in invasion response to cope with different circumstances and contexts, rather than a 'one size fits all' approach. While we find bio-mimicry to be a potentially useful system design tool, there are key differences between the immune and biosecurity systems that the analogy makes clear. Perhaps the most important of these stems from the inability of immune systems to imagine future threats. (C) 2014 Elsevier Ltd. All rights reserved.
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| 3. |
- Henderson, Neil C., et al.
(author)
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Targeting of alpha(v) integrin identifies a core molecular pathway that regulates fibrosis in several organs
- 2013
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In: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 19:12, s. 1617-1624
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Journal article (peer-reviewed)abstract
- Myofibroblasts are the major source of extracellular matrix components that accumulate during tissue fibrosis, and hepatic stellate cells (HSCs) are believed to be the major source of myofibroblasts in the liver. To date, robust systems to genetically manipulate these cells have not been developed. We report that Cre under control of the promoter of Pdgfrb (Pdgfrb-Cre) inactivates loxP-flanked genes in mouse HSCs with high efficiency. We used this system to delete the gene encoding alpha(v) integrin subunit because various alpha(v)-containing integrins have been suggested as central mediators of fibrosis in multiple organs. Such depletion protected mice from carbon tetrachloride-induced hepatic fibrosis, whereas global loss of beta(3), beta(5) or beta(6) integrins or conditional loss of beta(8) integrins in HSCs did not. We also found that Pdgfrb-Cre effectively targeted myofibroblasts in multiple organs, and depletion of the alpha(v) integrin subunit using this system was protective in other models of organ fibrosis, including pulmonary and renal fibrosis. Pharmacological blockade of alpha(v)-containing integrins by a small molecule (CWHM 12) attenuated both liver and lung fibrosis, including in a therapeutic manner. These data identify a core pathway that regulates fibrosis and suggest that pharmacological targeting of all alpha(v) integrins may have clinical utility in the treatment of patients with a broad range of fibrotic diseases.
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| 4. |
- Hogmalm, Anna, 1981, et al.
(author)
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beta6 Integrin subunit deficiency alleviates lung injury in a mouse model of bronchopulmonary dysplasia.
- 2010
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In: American journal of respiratory cell and molecular biology. - 1535-4989. ; 43:1, s. 88-98
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Journal article (peer-reviewed)abstract
- Pulmonary inflammation is associated with the development of bronchopulmonary dysplasia in premature infants. We have previously shown that perinatal pulmonary expression of human IL-1beta is sufficient to cause a lung disease similar to bronchopulmonary dysplasia, characterized by inflammation, impaired alveolarization, poor postnatal growth, and increased mortality in infant mice. The alphavbeta6 integrin plays a critical role in regulating inflammation in the adult lung. To study the role of the beta6 integrin subunit in neonatal inflammatory lung disease, we compared the pulmonary development in IL-1beta-expressing infant mice with wild-type or null beta6 integrin loci. Absence of the beta6 integrin subunit decreased the mortality and improved the postnatal growth of IL-1beta-expressing pups. The disrupted alveolar development of IL-1beta-expressing mice was improved by beta6 integrin deficiency. IL-1beta-expressing beta6(-/-) pups had shorter alveolar chord length and thinner alveolar walls than IL-1beta-expressing beta6(+/+) pups. In addition, the absence of the beta6 integrin subunit reduced IL-1beta-induced neutrophil and macrophage infiltration into the alveolar spaces. beta6 integrin subunit deficiency suppressed inflammation and goblet cell hyperplasia in the airways and alleviated airway remodeling in IL-1beta-expressing mice. The expression of the chemoattractant proteins, keratinocyte-derived chemokine, macrophage-inflammatory protein-2, calgranulin A, and calgranulin B, of osteopontin, and of the chitinase-like lectins, Ym1 and Ym2, was lower in IL-1beta-expressing beta6(-/-) than in IL-1beta-expressing beta6(+/+) mice. We conclude that absence of the beta6 integrin subunit protects the infant murine lung against IL-1beta-induced inflammation and injury.
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| 5. |
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| 6. |
- Santander, Nicolas, et al.
(author)
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Lack of Flvcr2 impairs brain angiogenesis without affecting the blood-brain barrier
- 2020
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In: Journal of Clinical Investigation. - 0021-9738 .- 1558-8238. ; 130:8, s. 4055-4068
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Journal article (peer-reviewed)abstract
- Fowler syndrome is a rare autosomal recessive brain vascular disorder caused by mutation in FLVCR2 in humans. The disease occurs during a critical period of brain vascular development, is characterized by glomeruloid vasculopathy and hydrocephalus, and is almost invariably prenatally fatal. Here, we sought to gain insights into the process of brain vascularization and the pathogenesis of Fowler syndrome by inactivating Flvcr2 in mice. We showed that Flvcr2 was necessary for angiogenic sprouting in the brain, but surprisingly dispensable for maintaining the blood-brain barrier. Endothelial cells lacking Flvcr2 had altered expression of angiogenic factors, failed to adopt tip cell properties, and displayed reduced sprouting, leading to vascular malformations similar to those seen in humans with Fowler syndrome. Brain hypovascularization was associated with hypoxia and tissue infarction, ultimately causing hydrocephalus and death of mutant animals. Strikingly, despite severe vascular anomalies and brain tissue infarction, the blood-brain barrier was maintained in Flvcr2 mutant mice. Our Fowler syndrome model therefore defined the pathobiology of this disease and provided new insights into brain angiogenesis by showing uncoupling of vessel morphogenesis and blood-brain barrier formation.
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| 7. |
- Sikkema, Lisa, et al.
(author)
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An integrated cell atlas of the lung in health and disease
- 2023
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In: Nature Medicine. - : Springer Nature. - 1078-8956 .- 1546-170X. ; 29:6, s. 1563-1577
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Journal article (peer-reviewed)abstract
- Single-cell technologies have transformed our understanding of human tissues. Yet, studies typically capture only a limited number of donors and disagree on cell type definitions. Integrating many single-cell datasets can address these limitations of individual studies and capture the variability present in the population. Here we present the integrated Human Lung Cell Atlas (HLCA), combining 49 datasets of the human respiratory system into a single atlas spanning over 2.4 million cells from 486 individuals. The HLCA presents a consensus cell type re-annotation with matching marker genes, including annotations of rare and previously undescribed cell types. Leveraging the number and diversity of individuals in the HLCA, we identify gene modules that are associated with demographic covariates such as age, sex and body mass index, as well as gene modules changing expression along the proximal-to-distal axis of the bronchial tree. Mapping new data to the HLCA enables rapid data annotation and interpretation. Using the HLCA as a reference for the study of disease, we identify shared cell states across multiple lung diseases, including SPP1 + profibrotic monocyte-derived macrophages in COVID-19, pulmonary fibrosis and lung carcinoma. Overall, the HLCA serves as an example for the development and use of large-scale, cross-dataset organ atlases within the Human Cell Atlas.
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