| 1. |
- Boström, Hans, et al.
(author)
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PDGF-A/PDGF alpha-receptor signaling is required for lung growth and the formation of alveoli but not for early lung branching morphogenesis
- 2002
-
In: Developmental Dynamics. - : Wiley. - 1058-8388 .- 1097-0177. ; 223:1, s. 155-162
-
Journal article (peer-reviewed)abstract
- Platelet-derived growth factors (PDGF) constitute a family of four gene products (PDGF-A-D) acting by means of two receptor tyrosine kinases, PDGFR alpha and beta. Three of the ligands (PDGF-A, -B, and -C) bind to PDGFR alpha with high affinity. Knockout of pdgf-a in mice has demonstrated a role for PDGF-A in the recruitment of smooth muscle cells to the alveolar sacs and their further compartmentalization into alveoli. Although this is a late, postnatal step in lung development, pdgf-a antisense oligonucleotides were previously shown to inhibit epithelial branching in rat lung explants in vitro, which reflects an early embryonic process. These conflicting results may be explained by substitution of genetic loss of pdgf-a by maternal transfer of PDGF-A to the knockout embryo or the presence of other PDGFR alpha agonists (PDGF-B and -C) in vivo, potentially masking an effect of PDGF-A on branching morphogenesis. Alternatively, the administration of pdgf-a antisense oligonucleotides affected other processes than the intended. To discriminate between these opposing possibilities, we have analyzed lung development in pdgfr alpha -/- embryos and lung primordia grown in vitro. Our analysis shows that, while the pdgfr alpha -/- lungs and explanted lung rudiments were smaller than normal, branching morphogenesis appears qualitatively intact and proceeds until at least embryonic day 15.5, generating both prospective conducting and respiratory airways. We conclude that, although PDGF-AA signaling over PDGFR alpha may have direct or indirect roles in overall lung growth, it does not specifically control early branching of the lung epithelium.
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| 2. |
- Abramsson, Alexandra, 1973, et al.
(author)
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Defective N-sulfation of heparan sulfate proteoglycans limits PDGF-BB binding and pericyte recruitment in vascular development
- 2007
-
In: GENES & DEVELOPMENT. - : Cold Spring Harbor Laboratory. - 0890-9369 .- 1549-5477. ; 21:3, s. 316-331
-
Journal article (peer-reviewed)abstract
- During vascular development, endothelial platelet-derived growth factor B (PDGF-B) is critical for pericyte recruitment. Deletion of the conserved C-terminal heparin-binding motif impairs PDGF-BB retention and pericyte recruitment in vivo, suggesting a potential role for heparan sulfate (HS) in PDGF-BB function during vascular development. We studied the participation of HS chains in pericyte recruitment using two mouse models with altered HS biosynthesis. Reduction of N-sulfation due to deficiency in N-deacetylase/N-sulfotransferase-1 attenuated PDGF-BB binding in vitro, and led to pericyte detachment and delayed pericyte migration in vivo. Reduced N-sulfation also impaired PDGF-BB signaling and directed cell migration, but not proliferation. In contrast, HS from glucuronyl C5-epimerase mutants, which is extensively N- and 6-O-sulfated, but lacks 2-O-sulfated L-iduronic acid residues, retained PDGF-BB in vitro, and pericyte recruitment in vivo was only transiently delayed. These observations were supported by in vitro characterization of the structural features in HS important for PDGF-BB binding. We conclude that pericyte recruitment requires HS with sufficiently extended and appropriately spaced N-sulfated domains to retain PDGF-BB and activate PDGF receptor β (PDGFRβ) signaling, whereas the detailed sequence of monosaccharide and sulfate residues does not appear to be important for this interaction.
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| 3. |
- Asp, Julia, 1973, et al.
(author)
-
Nonradioactive in situ hybridization on frozen sections and whole mounts.
- 2006
-
In: Methods in molecular biology (Clifton, N.J.). - 1064-3745. ; 326, s. 89-102
-
Journal article (peer-reviewed)abstract
- Nonradioactive in situ hybridization offers a unique opportunity to study gene expression on samples with preserved histological information. This method makes it possible to locate not only where in a tissue a particular gene is expressed, but in many cases also in which specific cell type it is active. Here, we describe our current protocols for in situ hybridization on frozen sections or whole mounts of mouse embryos. The protocols included describe synthesis of a digoxigenin-labeled probe, tissue handling, hybridization of the probe to the mRNA expressed in the sample and signal detection.
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| 4. |
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| 5. |
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| 6. |
- Betsholtz, Christer, 1959, et al.
(author)
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Role of platelet-derived growth factor in mesangium development and vasculopathies: lessons from platelet-derived growth factor and platelet-derived growth factor receptor mutations in mice.
- 2004
-
In: Current opinion in nephrology and hypertension. - 1062-4821. ; 13:1, s. 45-52
-
Journal article (peer-reviewed)abstract
- PURPOSE OF REVIEW: The phenotypic consequences of null mutations in the platelet-derived growth factor-B and the platelet-derived growth factor beta-receptor genes in mice have demonstrated that these proteins play pivotal roles in the development of the vascular smooth muscle cell lineage, including pericytes and mesangial cells. RECENT FINDINGS: The lethality of these mutants has precluded analysis of the physiological and pathophysiological consequences of platelet-derived growth factor-B and platelet-derived growth factor beta-receptor deficiency in adults. This review summarizes and discusses recent data from certain tissue-specific and subtle mutations in the platelet-derived growth factor-B and platelet-derived growth factor beta-receptor genes that are compatible with postnatal viability in spite of severe developmental deficits in pericyte and mesangial cell recruitment. In the postnatal period, the animals studied developed a characteristic set of pathological changes to small blood vessels of the retina and the kidney glomerulus, which sheds light on the importance of pericytes and mesangial cells for vascular integrity and function after birth. SUMMARY: These microvascular abnormalities and their consequences bear a resemblance to diabetic microangiopathy and nephropathy. The platelet-derived growth factor-B and platelet-derived growth factor beta-receptor mutant mouse models, therefore, might serve as valuable tools in the dissection of some of the pathogenic events in diabetic microangiopathy.
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| 7. |
- Bjarnegård, Mattias, 1970, et al.
(author)
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Endothelium-specific ablation of PDGFB leads to pericyte loss and glomerular, cardiac and placental abnormalities
- 2004
-
In: DEVELOPMENT. - : The Company of Biologists. - 0950-1991 .- 1477-9129. ; 131:8, s. 1847-1857
-
Journal article (peer-reviewed)abstract
- Platelet-derived growth factor-B (PDGFB) is necessary for normal cardiovascular development, but the relative importance of different cellular sources of PDGFB has not been established. Using Cre-lox techniques, we show here that genetic ablation of Pdgfb in endothelial cells leads to impaired recruitment of pericytes to blood vessels. The endothelium-restricted Pdgfb knockout mutants also developed organ defects including cardiac, placental and renal abnormalities. These defects were similar to those observed in Pdgfb null mice. However, in marked contrast to the embryonic lethality of Pdgfb null mutants, the endothelium-specific mutants survived into adulthood with persistent pathological changes, including brain microhemorrhages, focal astrogliosis, and kidney glomerulus abnormalities. This spectrum of pathological changes is reminiscent of diabetic microangiopathy, suggesting that the endothelium-restricted Pdgfb knockouts may serve as models for some of the pathogenic events of vascular complications to diabetes. Key words: PDGFB, Endothelium, Cre, loxP, Pericytes, Microaneurysm
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| 8. |
- Bondjers, Cecilia, 1974, et al.
(author)
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Microarray analysis of blood microvessels from PDGF-B and PDGF-Rbeta mutant mice identifies novel markers for brain pericytes.
- 2006
-
In: The FASEB journal : official publication of the Federation of American Societies for Experimental Biology. - : Wiley. - 1530-6860. ; 20:10, s. 1703-5
-
Journal article (peer-reviewed)abstract
- Normal blood microvessels are lined by pericytes, which contribute to microvessel development and stability through mechanisms that are poorly understood. Pericyte deficiency has been implicated in the pathogenesis of microvascular abnormalities associated with diabetes and tumors. However, the unambiguous identification of pericytes is still a problem because of cellular heterogeneity and few available molecular markers. Here we describe an approach to identify pericyte markers based on transcription profiling of pericyte-deficient brain microvessels isolated from platelet-derived growth factor (PDGF-B)-/- and PDGF beta receptor (PDGFRbeta)-/- mouse mutants. The approach was validated by the identification of known pericyte markers among the most down-regulated genes in PDGF-B-/- and PDGFRbeta-/- microvessels. Of candidates for novel pericyte markers, we selected ATP-sensitive potassium-channel Kir6.1 (also known as Kcnj8) and sulfonylurea receptor 2, (SUR2, also known as Abcc9), both part of the same channel complex, as well as delta homologue 1 (DLK1) for in situ hybridization, which demonstrated their specific expression in brain pericytes of mouse embryos. We also show that Kir6.1 is highly expressed in pericytes in brain but undetectable in pericytes in skin and heart. The three new brain pericyte markers are signaling molecules implicated in ion transport and intercellular signaling, potentially opening new windows on pericyte function in brain microvessels.
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| 9. |
- Bondjers, Cecilia, 1974, et al.
(author)
-
Transcription profiling of platelet-derived growth factor-B-deficient mouse embryos identifies RGS5 as a novel marker for pericytes and vascular smooth muscle cells.
- 2003
-
In: The American journal of pathology. - 0002-9440. ; 162:3, s. 721-9
-
Journal article (peer-reviewed)abstract
- All blood capillaries consist of endothelial tubes surrounded by mural cells referred to as pericytes. The origin, recruitment, and function of the pericytes is poorly understood, but the importance of these cells is underscored by the severe cardiovascular defects in mice genetically devoid of factors regulating pericyte recruitment to embryonic vessels, and by the association between pericyte loss and microangiopathy in diabetes mellitus. A general problem in the study of pericytes is the shortage of markers for these cells. To identify new markers for pericytes, we have taken advantage of the platelet-derived growth factor (PDGF)-B knockout mouse model, in which developing blood vessels in the central nervous system are almost completely devoid of pericytes. Using cDNA microarrays, we analyzed the gene expression in PDGF-B null embryos in comparison with corresponding wild-type embryos and searched for down-regulated genes. The most down-regulated gene present on our microarray was RGS5, a member of the RGS family of GTPase-activating proteins for G proteins. In situ hybridization identified RGS5 expression in brain pericytes, and in pericytes and vascular smooth muscle cells in certain other, but not all, locations. Absence of RGS5 expression in PDGF-B and PDGFR beta-null embryos correlated with pericyte loss in these mice. Residual RGS5 expression in rare pericytes suggested that RGS5 is a pericyte marker expressed independently of PDGF-B/R beta signaling. With RGS5 as a proof-of-principle, our data demonstrate the usefulness of microarray analysis of mouse models for abnormal pericyte development in the identification of new pericyte-specific markers.
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| 10. |
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| 11. |
- Enge, Maria, 1970, et al.
(author)
-
Endothelium-specific platelet-derived growth factor-B ablation mimics diabetic retinopathy.
- 2002
-
In: The EMBO journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 21:16, s. 4307-16
-
Journal article (peer-reviewed)abstract
- Loss of pericytes from the capillary wall is a hallmark of diabetic retinopathy, however, the pathogenic significance of this phenomenon is unclear. In previous mouse gene knockout models leading to pericyte deficiency, prenatal lethality has so far precluded analysis of postnatal consequences in the retina. We now report that endothelium-restricted ablation of platelet-derived growth factor-B generates viable mice with extensive inter- and intra-individual variation in the density of pericytes throughout the CNS. We found a strong inverse correlation between pericyte density and the formation of a range of retinal microvascular abnormalities strongly reminiscent of those seen in diabetic humans. Proliferative retinopathy invariably developed when pericyte density was <50% of normal. Our data suggest that a reduction of the pericyte density is sufficient to cause retinopathy in mice, implying that pericyte loss may also be a causal pathogenic event in human diabetic retinopathy.
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| 12. |
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| 13. |
- He, L, et al.
(author)
-
Glomerulus-specific mRNA transcripts and proteins identified through kidney expressed sequence tag database analysis
- 2007
-
In: Kidney International. - 1523-1755 .- 0085-2538. ; 71:9, s. 889-900
-
Journal article (peer-reviewed)abstract
- The kidney glomerulus plays a crucial role in blood filtration but the molecular composition and physiology of the glomerulus is not well understood. We previously constructed and large-scale sequenced four mouse glomerular expressed sequence tag (EST) libraries from newborn and adult mouse glomeruli. Here, we compared glomerular EST profiles with whole kidney EST profiles, thereby identifying 497 transcripts corresponding to UniGene clusters that were glomerulus-enriched, that is expressed more abundantly in glomeruli than in whole kidney. These include several known protein-coding glomerulus-specific transcripts critical for glomerulus development and function, but also a large number of gene transcripts, which have not previously been shown to be expressed in the glomerulus, or implicated in glomerular functions. We used in situ hybridization to demonstrate glomerulus-specific RNA expression for six novel glomerular genes and the public Human Protein Atlas to verify glomerular protein expression for another two. The higher mRNA abundance for the eight genes in glomeruli compared with whole kidney was also verified by Taqman quantitative polymerase chain reaction. We surmise that the further characterization of these genes and proteins will increase our understanding of glomerular development and physiology.
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| 14. |
- He, Liqun, et al.
(author)
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The glomerular transcriptome and a predicted protein-protein interaction network
- 2008
-
In: Journal of the American Society of Nephrology. - 1046-6673 .- 1533-3450. ; 19:2, s. 260-268
-
Journal article (peer-reviewed)abstract
- To increase our understanding of the molecular composition of the kidney glomerulus, we performed a meta-analysis of available glomerular transcriptional profiles made from mouse and man using five different methodologies. We generated a combined catalogue of glomerulus-enriched genes that emerged from these different sources and then used this to construct a predicted protein-protein interaction network in the glomerulus (GlomNet). The combined glomerulus-enriched gene catalogue provides the most comprehensive picture of the molecular composition of the glomerulus currently available, and GlomNet contributes an integrative systems biology approach to the understanding of glomerular signaling networks that operate during development, function, and disease.
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| 15. |
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| 16. |
- Kozaki, Koichi, et al.
(author)
-
Blockade of platelet-derived growth factor or its receptors transiently delays but does not prevent fibrous cap formation in ApoE null mice.
- 2002
-
In: The American journal of pathology. - 0002-9440. ; 161:4, s. 1395-407
-
Journal article (peer-reviewed)abstract
- Platelet-derived growth factor (PDGF) is a potent stimulant of smooth muscle cell migration and proliferation in culture. To test the role of PDGF in the accumulation of smooth muscle cells in vivo, we evaluated ApoE -/- mice that develop complex lesions of atherosclerosis. Fetal liver cells from PDGF-B-deficient embryos were used to replace the circulating cells of lethally irradiated ApoE -/- mice. One month after transplant, all monocytes in PDGF-B -/- chimeras are of donor origin (lack PDGF), and no PDGF-BB is detected in circulating platelets, primary sources of PDGF in lesions. Although lesion volumes are comparable in the PDGF-B +/+ and -/- chimeras at 35 weeks, lesions in PDGF-B -/- chimeras contain mostly macrophages, appear less mature, and have a reduced frequency of fibrous cap formation as compared with PDGF-B +/+ chimeras. However, after 45 weeks, smooth muscle cell accumulation in fibrous caps is indistinguishable in the two groups. Comparison of elicited peritoneal macrophages by RNase protection assay shows an altered cytokine and cytokine receptor profile in PDGF-B -/- chimeras. ApoE -/- mice were also treated for up to 50 weeks with a PDGF receptor antagonist that blocks all three PDGF receptor dimers. Blockade of the PDGF receptors similarly delays, but does not prevent, accumulation of smooth muscle and fibrous cap formation. Thus, elimination of PDGF-B from circulating cells or blockade of PDGF receptors does not appear sufficient to prevent smooth muscle accumulation in advanced lesions of atherosclerosis.
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| 17. |
- Lindblom, Per, 1974, et al.
(author)
-
Endothelial PDGF-B retention is required for proper investment of pericytes in the microvessel wall.
- 2003
-
In: Genes & development. - : Cold Spring Harbor Laboratory. - 0890-9369 .- 1549-5477. ; 17:15, s. 1835-40
-
Journal article (peer-reviewed)abstract
- Several platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) family members display C-terminal protein motifs that confer retention of the secreted factors within the pericellular space. To address the role of PDGF-B retention in vivo, we deleted the retention motif by gene targeting in mice. This resulted in defective investment of pericytes in the microvessel wall and delayed formation of the renal glomerulus mesangium. Long-term effects of lack of PDGF-B retention included severe retinal deterioration, glomerulosclerosis, and proteinuria. We conclude that retention of PDGF-B in microvessels is essential for proper recruitment and organization of pericytes and for renal and retinal function in adult mice.
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| 18. |
- Lundkvist, Andrea, 1975, et al.
(author)
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Under stress, the absence of intermediate filaments from Müller cells in the retina has structural and functional consequences.
- 2004
-
In: Journal of cell science. - : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 117:Pt 16, s. 3481-8
-
Journal article (peer-reviewed)abstract
- In epithelial and muscle cells, intermediate filaments (IFs) are important for resistance to mechanical stress. The aim of this study was to elucidate whether IFs are also important for providing resistance to mechanical stress in the Müller cells of the retina and whether this has any pathophysiological consequences. We used mice deficient in IF proteins glial fibrillary acidic protein and/or vimentin (GFAP(-/-), Vim(-/-) and GFAP(-/-) Vim(-/-)), and stress on the retina was applied by excision of the eyes immediately post mortem (compared with in situ fixation) or by inducing a neovascular response to oxygen-induced retinopathy (OIR). The structure of unchallenged retinas was normal, but mechanical stress caused local separation of the inner limiting membrane (ILM) and adjacent tissue from the rest of the retina in GFAP(-/-) Vim(-/-) mice and, to a lesser extent, in Vim(-/-) mice. This detachment occurred within the endfeet of Müller cells, structures normally rich in IFs but IF-free in GFAP(-/-) Vim(-/-) mice. Hypoxia-induced neovascularization was comparable in all groups of mice with respect to the retinal surface area occupied by new vessels. However, the vessels traversed the ILM and penetrated the vitreous body less frequently than in wild-type retinas (31-55% in Vim(-/-), 66-79% in GFAP(-/-) Vim(-/-)). We conclude that IFs are important for maintaining the mechanical integrity of Müller-cell endfeet and the inner retinal layers under a mechanical challenge. Furthermore, the absence of IFs in Müller cells leads to an abnormal response of the vascular system to ischemia, specifically decreased ability of newly formed blood vessels to traverse the ILM.
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| 19. |
- Nyström, Henrik, 1977, et al.
(author)
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Platelet-derived growth factor B retention is essential for development of normal structure and function of conduit vessels and capillaries
- 2006
-
In: Cardiovasc Res. - : Oxford University Press (OUP). - 0008-6363. ; 71:3, s. 557-65
-
Journal article (peer-reviewed)abstract
- OBJECTIVE: Extracellular retention of PDGF-B has been proposed to play an important role in PDGF-B signalling. We used the PDGF-B retention motif knockout mouse (RetKO) to study the effects of retention motif deletion on development of micro- and macrovascular structure and function. METHODS: Passive and active properties of conduit vessels were studied using myograph techniques and histological examination. Capillary structure and function was studied using measurements of capillary density in skeletal muscle and by assessing aerobic physical performance in a treadmill setup. Cardiac function was assessed using echocardiography. RESULTS: Myograph experiments revealed an increased diameter and stiffness of the aorta in RetKO. Histological examination showed increased media collagen content and a decreased number of aortic wall layers, however with a similar number of vascular smooth muscle cells. This outward eutrophic remodelling of the aorta was accompanied by endothelial dysfunction. RetKO showed decreased capillary density in skeletal muscle and signs of a defective delivery of capillary oxygen to skeletal muscle, as shown by a decreased physical performance. In RetKO mice, echocardiography revealed an adaptive eccentric cardiac hypertrophy. CONCLUSION: We conclude that retention of PDGF-B during development is essential for a normal conduit vessel function in the adult mouse. Furthermore, PDGF-B retention is also necessary for the development of an adequate capillary density, and thereby for a normal oxygen delivery to skeletal muscle. The lack of primary effects on cardiac function supports the redundant role of PDGF-B in cardiac development.
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| 20. |
- Popova, Svetlana N., et al.
(author)
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The mesenchymal alpha 11 beta 1 integrin attenuates PDGF-BB-stimulated chemotaxis of embryonic fibroblasts on collagens
- 2004
-
In: DEVELOPMENTAL BIOLOGY. - 0012-1606. ; 270:2, s. 427-442
-
Journal article (peer-reviewed)abstract
- α11β1 constitutes the most recent addition to the integrin family and has been shown to display a binding preference for interstitial collagens found in mesenchymal tissues. We have previously observed that when α11β1 integrin is expressed in cells lacking endogenous collagen receptors, it can mediate PDGF-BB-dependent chemotaxis on collagen I in vitro. To determine in which cells PDGF and α11β1 might cooperate in regulating cell migration in vivo, we studied in detail the expression and distribution of α11 integrin chain in mouse embryos and tested the ability of PDGF isoforms to stimulate the α11β1-mediated cell migration of embryonic fibroblasts. Full-length mouse α11 cDNA was sequenced and antibodies were raised to deduced α11 integrin amino acid sequence. In the embryonic mouse head, α11 protein and RNA were localized to ectomesenchymally derived cells. In the periodontal ligament, α11β1 was expressed as the only detectable collagen-binding integrin, and α11β1 is thus a major receptor for cell migration and matrix organization in this cell population. In the remainder of the embryo, the α11 chain was expressed in a subset of mesenchymal cells including tendon/ligament fibroblasts, perichondrial cells, and intestinal villi fibroblasts. Most of the α11-expressing cells also expressed the α2 integrin chain, but no detectable overlap was found with the α1 integrin chain. In cells expressing multiple collagen receptors, these might function to promote a more stable cell adhesion and render the cells more resistant to chemotactic stimuli. Wild-type embryonic fibroblasts activated mainly the PDGF β receptor in response to PDGF-BB and migrated on collagens I, II, III, IV, V, and XI in response to PDGF-BB in vitro, whereas mutant fibroblasts that lacked α11β1 in their collagen receptor repertoire showed a stronger chemotactic response on collagens when stimulated with PDGF-BB. In the cellular context of embryonic fibroblasts, α11β1 is thus anti-migratory. We speculate that the PDGF BB-dependent cell migration of mesenchymal cells is tightly regulated by the collagen receptor repertoire, and disturbances of this repertoire might lead to unregulated cell migration that could affect normal embryonic development and tissue structure. Keywords: α11β1 integrin; Immunohistochemistry; In situ hybridization; Mouse embryogenesis; Cell migration
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| 21. |
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| 22. |
- Rymo, Simin, 1959, et al.
(author)
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A Two-Way Communication between Microglial Cells and Angiogenic Sprouts Regulates Angiogenesis in Aortic Ring Cultures
- 2011
-
In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:1
-
Journal article (peer-reviewed)abstract
- Background: Myeloid cells have been associated with physiological and pathological angiogenesis, but their exact functions in these processes remain poorly defined. Monocyte-derived tissue macrophages of the CNS, or microglial cells, invade the mammalian retina before it becomes vascularized. Recent studies correlate the presence of microglia in the developing CNS with vascular network formation, but it is not clear whether the effect is directly caused by microglia and their contact with the endothelium. Methodology/Principal Findings: We combined in vivo studies of the developing mouse retina with in vitro studies using the aortic ring model to address the role of microglia in developmental angiogenesis. Our in vivo analyses are consistent with previous findings that microglia are present at sites of endothelial tip-cell anastomosis, and genetic ablation of microglia caused a sparser vascular network associated with reduced number of filopodia-bearing sprouts. Addition of microglia in the aortic ring model was sufficient to stimulate vessel sprouting. The effect was independent of physical contact between microglia and endothelial cells, and could be partly mimicked using microglial cell-conditioned medium. Addition of VEGF-A promoted angiogenic sprouts of different morphology in comparison with the microglial cells, and inhibition of VEGF-A did not affect the microglia-induced angiogenic response, arguing that the proangiogenic factor(s) released by microglia is distinct from VEGF-A. Finally, microglia exhibited oriented migration towards the vessels in the aortic ring cultures. Conclusions/Significance: Microglia stimulate vessel sprouting in the aortic ring cultures via a soluble microglial-derived product(s), rather than direct contact with endothelial cells. The observed migration of microglia towards the growing sprouts suggests that their position near endothelial tip-cells could result from attractive cues secreted by the vessels. Our data reveals a two-way communication between microglia and vessels that depends on soluble factors and should extend the understanding of how microglia promote vascular network formation.
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| 23. |
- Takemoto, Minoru, et al.
(author)
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A new method for large scale isolation of kidney glomeruli from mice.
- 2002
-
In: The American journal of pathology. - 0002-9440. ; 161:3, s. 799-805
-
Journal article (peer-reviewed)abstract
- Here we report a new isolation method for mouse glomeruli. The method is fast and simple and allows for the isolation of virtually all glomeruli present in the adult mouse kidney with minimal contamination of nonglomerular cells. Mice were perfused through the heart with magnetic 4.5- micro m diameter Dynabeads. Kidneys were minced into small pieces, digested by collagenase, filtered, and collected using a magnet. The number of glomeruli retrieved from one adult mouse was 20,131 +/- 4699 (mean +/- SD, n = 14) with a purity of 97.5 +/- 1.7%. The isolated glomeruli retained intact morphology, as confirmed by light and electron microscopy, as well as intact mRNA integrity, as confirmed by Northern blot analysis. The method was applicable also to newborn mice, which allows for the isolation of immature developmental stage glomeruli. This method makes feasible transcript profiling and proteomic analysis of the developing, healthy and diseased mouse glomerulus.
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| 24. |
- Takemoto, Minoru, et al.
(author)
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Large-scale identification of genes implicated in kidney glomerulus development and function.
- 2006
-
In: The EMBO journal. - : Wiley. - 0261-4189 .- 1460-2075. ; 25:5, s. 1160-74
-
Journal article (peer-reviewed)abstract
- To advance our understanding of development, function and diseases in the kidney glomerulus, we have established and large-scale sequenced cDNA libraries from mouse glomeruli at different stages of development, resulting in a catalogue of 6053 different genes. The glomerular cDNA clones were arrayed and hybridized against a series of labeled targets from isolated glomeruli, non-glomerular kidney tissue, FACS-sorted podocytes and brain capillaries, which identified over 300 glomerular cell-enriched transcripts, some of which were further sublocalized to podocytes, mesangial cells and juxtaglomerular cells by in situ hybridization. For the earliest podocyte marker identified, Foxc2, knockout mice were used to analyze the role of this protein during glomerular development. We show that Foxc2 controls the expression of a distinct set of podocyte genes involved in podocyte differentiation and glomerular basement membrane maturation. The primary podocyte defects also cause abnormal differentiation and organization of the glomerular vascular cells. We surmise that studies on the other novel glomerulus-enriched transcripts identified in this study will provide new insight into glomerular development and pathomechanisms of disease.
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| 25. |
- Tang, Jingjing, et al.
(author)
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The absence of platelet-derived growth factor-B in circulating cells promotes immune and inflammatory responses in atherosclerosis-prone ApoE-/- mice.
- 2005
-
In: The American journal of pathology. - 0002-9440. ; 167:3, s. 901-12
-
Journal article (peer-reviewed)abstract
- Both innate and adaptive immunity contribute to the progression of inflammatory-fibrotic lesions of atherosclerosis. Although platelet-derived growth factor (PDGF)-B has been investigated as a stimulant of smooth muscle cells in vascular diseases, its effects on the immune response during disease have not been evaluated in vivo. We used hematopoietic chimeras generated after lethal irradiation of ApoE-/- recipients to test the role of PDGF in atherosclerosis. Monocyte accumulation in early atherosclerotic lesions increased 1.9-fold in ApoE-/-/PDGF-B-/- chimeras. Lymphocytes from null chimeras showed a 1.6- to 2.0-fold increase in the number of activated CD4(+) T cells and a 2.5-fold elevation of interferon-gamma-secreting CD4(+) T cells on ex vivo challenge with modified low-density lipoprotein. Splenocyte transcript levels were also altered with a twofold decrease in interleukin-10 and 1.7- and 3.0-fold increases in interleukin-18 and CCR 5, respectively. These cellular and molecular changes were consistent with a shift to a proinflammatory phenotype in null chimeras. Our data also demonstrated for the first time the presence of a recently discovered family of negative regulators of innate and adaptive immunity, the suppressors of cytokine signaling (SOCS), in developing atherosclerotic lesions. Thus, our studies identify two independent negative immune regulatory pathways-PDGF-B and SOCS-that may help limit lesion expansion.
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| 26. |
- Tobin, N. P., et al.
(author)
-
An Endothelial Gene Signature Score Predicts Poor Outcome in Patients with Endocrine-Treated, Low Genomic Grade Breast Tumors
- 2016
-
In: Clinical Cancer Research. - : American Association for Cancer Research (AACR). - 1078-0432 .- 1557-3265. ; 22:10, s. 2417-2426
-
Journal article (peer-reviewed)abstract
- Purpose: The ability of vascular genes to provide treatment predictive information in breast cancer patients remains unclear. As such, we assessed the expression of genes representative of normal endothelial microvasculature (MV) in relation to treatment-specific patient subgroups. Experimental Design: We used expression data from 993 breast tumors to assess 57 MV genes (summarized to yield an MV score) as well as the genomic grade index (GGI) and PAM50 signatures. MV score was compared with CD31 staining by correlation and gene ontology (GO) analysis, along with clinicopathologic characteristics and PAM50 subtypes. Uni-, multivariate, and/or t-test analyses were performed in all and treatment-specific subgroups, along with a clinical trial cohort of patients with metastatic breast cancer, seven of whom received antiangiogenic therapy. Results: MV score did not correlate with microvessel density (correlation = 0.096), but displayed enrichment for angiogenic GO terms, and was lower in Luminal B tumors. In endocrine-treated patients, a high MV score was associated with decreased risk of metastasis [HR 0.58; 95% confidence interval (CI), 0.38-0.89], even after adjusting for histologic grade, but not GGI or PAM50. Subgroup analysis showed the prognostic strength of the MV score resided in low genomic grade tumors and MV score was significantly increased in metastatic breast tumors after treatment with sunitinib + docetaxel (P = 0.031). Conclusions: MV score identifies two groups of better and worse survival in low-risk endocrine-treated breast cancer patients. We also show normalization of tumor vasculature on a transcriptional level in response to an angiogenic inhibitor in human breast cancer samples. (C) 2016 AACR.
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| 27. |
- Wallgard, Elisabet, et al.
(author)
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Identification of a core set of 58 gene transcripts with broad and specific expression in the microvasculature.
- 2008
-
In: Arteriosclerosis, thrombosis, and vascular biology. - 1524-4636 .- 1079-5642. ; 28:8, s. 1469-76
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Pathological angiogenesis is an integral component of many diseases. Antiangiogenesis and vascular targeting are therefore promising new therapeutic principles. However, few endothelial-specific putative drug targets have been identified, and information is still limited about endothelial-specific molecular processes. Here we aimed at determining the endothelial cell-specific core transcriptome in vivo. METHODS AND RESULTS: Analysis of publicly available microarray data identified a mixed vascular/lung cluster of 132 genes that correlated with known endothelial markers. Filtering against kidney glomerular/nonglomerular and brain vascular/nonvascular microarray profiles separated contaminating lung markers, leaving 58 genes with broad and specific microvascular expression. More than half of these have not previously been linked to endothelial functions or studied in detail before. The endothelial cell-specific expression of a selected subset of these, Eltd1, Gpr116, Ramp2, Slc9a3r2, Slc43a3, Rasip1, and NM_023516, was confirmed by real-time quantitative polymerase chain reaction and/or immunohistochemistry. CONCLUSIONS: We have used a combination of publicly available and own microarray data to identify 58 gene transcripts with broad yet specific expression in microvascular endothelium. Most of these have unknown functions, but many of them are predicted to be cell surface expressed or implicated in cell signaling processes and should therefore be explored as putative microvascular drug targets.
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| 28. |
- Xian, Xiaojie, 1971, et al.
(author)
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Pericytes limit tumor cell metastasis.
- 2006
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In: The Journal of clinical investigation. - 0021-9738. ; 116:3, s. 642-51
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Journal article (peer-reviewed)abstract
- Previously we observed that neural cell adhesion molecule (NCAM) deficiency in beta tumor cells facilitates metastasis into distant organs and local lymph nodes. Here, we show that NCAM-deficient beta cell tumors grew leaky blood vessels with perturbed pericyte-endothelial cell-cell interactions and deficient perivascular deposition of ECM components. Conversely, tumor cell expression of NCAM in a fibrosarcoma model (T241) improved pericyte recruitment and increased perivascular deposition of ECM molecules. Together, these findings suggest that NCAM may limit tumor cell metastasis by stabilizing the microvessel wall. To directly address whether pericyte dysfunction increases the metastatic potential of solid tumors, we studied beta cell tumorigenesis in primary pericyte-deficient Pdgfb(ret/ret) mice. This resulted in beta tumor cell metastases in distant organs and local lymph nodes, demonstrating a role for pericytes in limiting tumor cell metastasis. These data support a new model for how tumor cells trigger metastasis by perturbing pericyte-endothelial cell-cell interactions.
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