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Abstract
The blood-spinal cord barrier (BSCB) regulates molecular exchange between blood and spinal cord. Pericytes are presumed to be important cellular constituents of the BSCB. However, the regional abundance and vascular functions of spinal cord pericytes have yet to be determined. Utilizing wild-type mice, we show that spinal cord pericyte capillary coverage and number compared with the brain regions are reduced most prominently in the anterior horn. Regional pericyte variations are highly correlated with: (1) increased capillary permeability to 350 Da, 40,000 Da, and 150,000 Da, but not 2,000,000 Da fluorescent vascular tracers in cervical, thoracic, and lumbar regions and (2) diminished endothelial zonula occludens-1 (ZO-1) and occludin tight junction protein expression. Pericyte-deficient mutations (Pdgfrβ(F7/F7) mice) resulted in additional pericyte reductions in spinal cord capillaries leading to overt BSCB disruption to serum proteins, accumulation in motor neurons of cyotoxic thrombin and fibrin and motor neuron loss. Barrier disruption in perciyte-deficient mice coincided with further reductions in ZO-1 and occludin. These data suggest that pericytes contribute to proper function of the BSCB at the capillary level. Regional reductions in spinal cord pericytes may provide a cellular basis for heightened spinal cord barrier capillary permeability and motor neuron loss.
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102
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Baek ST, Tallquist MD. Nf1 limits epicardial derivative expansion by regulating epithelial to mesenchymal transition and proliferation. Development 2012; 139:2040-9. [PMID: 22535408 DOI: 10.1242/dev.074054] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The epicardium is the primary source of coronary vascular smooth muscle cells (cVSMCs) and fibroblasts that reside in the compact myocardium. To form these epicardial-derived cells (EPDCs), the epicardium undergoes the process of epithelial to mesenchymal transition (EMT). Although several signaling pathways have been identified that disrupt EMT, no pathway has been reported that restricts this developmental process. Here, we identify neurofibromin 1 (Nf1) as a key mediator of epicardial EMT. To determine the function of Nf1 during epicardial EMT and the formation of epicardial derivatives, cardiac fibroblasts and cVSMCs, we generated mice with a tissue-specific deletion of Nf1 in the epicardium. We found that mutant epicardial cells transitioned more readily to mesenchymal cells in vitro and in vivo. The mesothelial epicardium lost epithelial gene expression and became more invasive. Using lineage tracing of EPDCs, we found that the process of EMT occurred earlier in Nf1 mutant hearts, with an increase in epicardial cells entering the compact myocardium. Moreover, loss of Nf1 caused increased EPDC proliferation and resulted in more cardiac fibroblasts and cVSMCs. Finally, we were able to partially reverse the excessive EMT caused by loss of Nf1 by disrupting Pdgfrα expression in the epicardium. Conversely, Nf1 activation was able to inhibit PDGF-induced epicardial EMT. Our results demonstrate a regulatory role for Nf1 during epicardial EMT and provide insights into the susceptibility of patients with disrupted NF1 signaling to cardiovascular disease.
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Affiliation(s)
- Seung Tae Baek
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
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103
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Sims-Lucas S, Di Giovanni V, Schaefer C, Cusack B, Eswarakumar VP, Bates CM. Ureteric morphogenesis requires Fgfr1 and Fgfr2/Frs2α signaling in the metanephric mesenchyme. J Am Soc Nephrol 2012; 23:607-17. [PMID: 22282599 DOI: 10.1681/asn.2011020165] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Conditional deletion of fibroblast growth factor receptors (Fgfrs) 1 and 2 in the metanephric mesenchyme (MM) of mice leads to a virtual absence of MM and unbranched ureteric buds that are occasionally duplex. Deletion of Fgfr2 in the MM leads to kidneys with cranially displaced ureteric buds along the Wolffian duct or duplex ureters. Mice with point mutations in Fgfr2's binding site for the docking protein Frs2α (Fgfr2(LR/LR)), however, have normal kidneys; the roles of the Fgfr2/Frs2α signaling axis in MM development and regulating the ureteric bud induction site are incompletely understood. Here, we generated mice with both Fgfr1 deleted in the MM and Fgfr2(LR/LR) point mutations (Fgfr1(Mes-/-)Fgfrf2(LR/LR)). Unlike mice lacking both Fgfr1 and Fgfr2 in the MM, these mice had no obvious MM defects but had cranially displaced or duplex ureteric buds, probably as a result of decreased Bmp4 expression. Fgfr1(Mes-/-)Fgfr2(LR/LR) mice also had subsequent defects in ureteric morphogenesis, including dilated, hyperproliferative tips and decreased branching. Ultimately, they developed progressive renal cystic dysplasia associated with abnormally oriented cell division. Furthermore, mutants had increased and ectopic expression of Ret and its downstream targets in ureteric trunks, and exhibited upregulation of Ret/Etv4/5 signaling effectors, including Met, Myb, Cxcr4, and Crlf1. These defects were associated with reduced expression of Bmp4 in mesenchymal cells near mutant ureteric bud tips. Taken together, these results demonstrate that Fgfr2/Frs2α signaling in the MM promotes Bmp4 expression, which represses Ret levels and signaling in the ureteric bud to ensure normal ureteric morphogenesis.
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Affiliation(s)
- Sunder Sims-Lucas
- Rangos Research Center, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15201, USA
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104
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Influence of morphine on pericyte-endothelial interaction: implications for antiangiogenic therapy. JOURNAL OF ONCOLOGY 2012; 2012:458385. [PMID: 22315595 PMCID: PMC3270445 DOI: 10.1155/2012/458385] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 10/07/2011] [Indexed: 12/12/2022]
Abstract
Morphine stimulates tumor angiogenesis and cancer progression in mice. We examined if morphine influences endothelial-pericyte interaction via platelet-derived growth factor-BB (PDGF-BB) and PDGF receptor-β (PDGFR-β). Clinically relevant doses of morphine stimulated PDGF-BB secretion from human umbilical vein endothelial cells and activated PDGFR-β and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) phosphorylation in human pericytes. These in vitro effects of morphine were translated into promotion of tumor angiogenesis in a transgenic mice model of breast cancer when treated with clinically used dose of morphine. Increased vessel-associated immunoreactivity of desmin and PDGFR-β was observed on pericytes in tumors of morphine-treated mice. These data suggest that morphine potentiates endothelial-pericyte interaction via PDGF-BB/PDGFR-β signaling and promotes tumor angiogenesis, pericyte recruitment, and coverage of tumor vessels. We speculate that morphine may impair the effectiveness of antiangiogenic therapy by influencing vascular pericyte coverage.
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105
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Winkler EA, Bell RD, Zlokovic BV. Central nervous system pericytes in health and disease. Nat Neurosci 2011; 14:1398-1405. [PMID: 22030551 DOI: 10.1038/nn.2946] [Citation(s) in RCA: 703] [Impact Index Per Article: 54.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Pericytes are uniquely positioned within the neurovascular unit to serve as vital integrators, coordinators and effectors of many neurovascular functions, including angiogenesis, blood-brain barrier (BBB) formation and maintenance, vascular stability and angioarchitecture, regulation of capillary blood flow and clearance of toxic cellular byproducts necessary for proper CNS homeostasis and neuronal function. New studies have revealed that pericyte deficiency in the CNS leads to BBB breakdown and brain hypoperfusion resulting in secondary neurodegenerative changes. Here we review recent progress in understanding the biology of CNS pericytes and their role in health and disease.
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Affiliation(s)
- Ethan A Winkler
- Center for Neurodegenerative and Vascular Brain Disorders, Department of Neurosurgery and Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - Robert D Bell
- Center for Neurodegenerative and Vascular Brain Disorders, Department of Neurosurgery and Neurology, University of Rochester Medical Center, Rochester, New York, USA
| | - Berislav V Zlokovic
- Center for Neurodegenerative and Vascular Brain Disorders, Department of Neurosurgery and Neurology, University of Rochester Medical Center, Rochester, New York, USA
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106
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Castilho-Fernandes A, de Almeida DC, Fontes AM, Melo FUF, Picanço-Castro V, Freitas MC, Orellana MD, Palma PVB, Hackett PB, Friedman SL, Covas DT. Human hepatic stellate cell line (LX-2) exhibits characteristics of bone marrow-derived mesenchymal stem cells. Exp Mol Pathol 2011; 91:664-72. [PMID: 21930125 DOI: 10.1016/j.yexmp.2011.09.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 09/02/2011] [Accepted: 09/02/2011] [Indexed: 12/13/2022]
Abstract
The LX-2 cell line has characteristics of hepatic stellate cells (HSCs), which are considered pericytes of the hepatic microcirculatory system. Recent studies have suggested that HSCs might have mesenchymal origin. We have performed an extensive characterization of the LX-2 cells and have compared their features with those of mesenchymal cells. Our data show that LX-2 cells have a phenotype resembling activated HSCs as well as bone marrow-derived mesenchymal stem cells (BM-MSCs). Our immunophenotypic analysis showed that LX-2 cells are positive for activated HSC markers (αSMA, GFAP, nestin and CD271) and classical mesenchymal makers (CD105, CD44, CD29, CD13, CD90, HLA class-I, CD73, CD49e, CD166 and CD146) but negative for the endothelial marker CD31 and endothelial progenitor cell marker CD133 as well as hematopoietic markers (CD45 and CD34). LX-2 cells also express the same transcripts found in immortalized and primary BM-MSCs (vimentin, annexin 5, collagen 1A, NG2 and CD140b), although at different levels. We show that LX-2 cells are capable to differentiate into multilineage mesenchymal cells in vitro and can stimulate new blood vessel formation in vivo. LX-2 cells appear not to possess tumorigenic potential. Thus, the LX-2 cell line behaves as a multipotent cell line with similarity to BM-MSCs. This line should be useful for further studies to elucidate liver regeneration mechanisms and be the foundation for development of hepatic cell-based therapies.
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Affiliation(s)
- Andrielle Castilho-Fernandes
- Faculty of Medicine of Ribeirão Preto, Department of Clinical Medicine, University of São Paulo, Av. Bandeirantes, 3900 (6° andar do HC) Ribeirão Preto 14048-900, Brazil.
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107
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Olson LE, Soriano P. PDGFRβ signaling regulates mural cell plasticity and inhibits fat development. Dev Cell 2011; 20:815-26. [PMID: 21664579 DOI: 10.1016/j.devcel.2011.04.019] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 03/09/2011] [Accepted: 04/27/2011] [Indexed: 12/25/2022]
Abstract
Mural cells (pericytes and vascular smooth muscle cells) provide trophic and structural support to blood vessels. Vascular smooth muscle cells alternate between a synthetic/proliferative state and a differentiated/contractile state, but the dynamic states of pericytes are poorly understood. To explore the cues that regulate mural cell differentiation and homeostasis, we have generated conditional knockin mice with activating mutations at the PDGFRβ locus. We show that increased PDGFRβ signaling drives cell proliferation and downregulates differentiation genes in aortic vascular smooth muscle. Increased PDGFRβ signaling also induces a battery of immune response genes in pericytes and mesenchymal cells and inhibits differentiation of white adipocytes. Mural cells are emerging as multipotent progenitors of pathophysiological importance, and we identify PDGFRβ signaling as an important in vivo regulator of their progenitor potential.
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Affiliation(s)
- Lorin E Olson
- Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA.
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108
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Ghosh S, Paez-Cortez JR, Boppidi K, Vasconcelos M, Roy M, Cardoso W, Ai X, Fine A. Activation dynamics and signaling properties of Notch3 receptor in the developing pulmonary artery. J Biol Chem 2011; 286:22678-87. [PMID: 21536678 PMCID: PMC3121411 DOI: 10.1074/jbc.m111.241224] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 04/20/2011] [Indexed: 11/06/2022] Open
Abstract
Notch3 signaling is fundamental for arterial specification of systemic vascular smooth muscle cells (VSMCs). However, the developmental role and signaling properties of the Notch3 receptor in the mouse pulmonary artery remain unknown. Here, we demonstrate that Notch3 is expressed selectively in pulmonary artery VSMCs, is activated from late fetal to early postnatal life, and is required to maintain the morphological characteristics and smooth muscle gene expression profile of the pulmonary artery after birth. Using a conditional knock-out mouse model, we show that Notch3 receptor activation in VSMCs is Jagged1-dependent. In vitro VSMC lentivirus-mediated Jagged1 knockdown, confocal localization analysis, and co-culture experiments revealed that Notch3 activation is cell-autonomous and occurs through the physical engagement of Notch3 and VSMC-derived Jagged1 in the interior of the same cell. Although the current models of mammalian Notch signaling involve a two-cell system composed of a signal-receiving cell that expresses a Notch receptor on its surface and a neighboring signal-sending cell that provides membrane-bound activating ligand, our data suggest that pulmonary artery VSMC Notch3 activation is cell-autonomous. This unique mechanism of Notch activation may play an important role in the maturation of the pulmonary artery during the transition to air breathing.
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Affiliation(s)
- Shamik Ghosh
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Jesus R. Paez-Cortez
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Karthik Boppidi
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Michelle Vasconcelos
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Monideepa Roy
- the Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Wellington Cardoso
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Xingbin Ai
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
| | - Alan Fine
- From the Pulmonary Center, Boston University School of Medicine, Boston, Massachusetts 02118, and
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109
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Smith CL, Baek ST, Sung CY, Tallquist MD. Epicardial-derived cell epithelial-to-mesenchymal transition and fate specification require PDGF receptor signaling. Circ Res 2011; 108:e15-26. [PMID: 21512159 DOI: 10.1161/circresaha.110.235531] [Citation(s) in RCA: 249] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
RATIONALE In early heart development, platelet-derived growth factor (PDGF) receptor expression in the heart ventricles is restricted to the epicardium. Previously, we showed that PDGFRβ is required for coronary vascular smooth muscle cell (cVSMC) development, but a role for PDGFRα has not been identified. Therefore, we investigated the combined and independent roles of these receptors in epicardial development. OBJECTIVE To understand the contribution of PDGF receptors in epicardial development and epicardial-derived cell fate determination. METHODS AND RESULTS By generating mice with epicardial-specific deletion of the PDGF receptors, we found that epicardial epithelial-to-mesenchymal transition (EMT) was defective. Sox9, an SRY-related transcription factor, was reduced in PDGF receptor-deficient epicardial cells, and overexpression of Sox9 restored epicardial migration, actin reorganization, and EMT gene expression profiles. The failure of epicardial EMT resulted in hearts that lacked epicardial-derived cardiac fibroblasts and cVSMC. Loss of PDGFRα resulted in a specific disruption of cardiac fibroblast development, whereas cVSMC development was unperturbed. CONCLUSIONS Signaling through both PDGF receptors is necessary for epicardial EMT and formation of epicardial-mesenchymal derivatives. PDGF receptors also have independent functions in the development of specific epicardial-derived cell fates.
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Affiliation(s)
- Christopher L Smith
- Department of Molecular Biology, MC9148, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
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110
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Bell RD, Winkler EA, Sagare AP, Singh I, LaRue B, Deane R, Zlokovic BV. Pericytes control key neurovascular functions and neuronal phenotype in the adult brain and during brain aging. Neuron 2010; 68:409-27. [PMID: 21040844 PMCID: PMC3056408 DOI: 10.1016/j.neuron.2010.09.043] [Citation(s) in RCA: 1074] [Impact Index Per Article: 76.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2010] [Indexed: 12/13/2022]
Abstract
Pericytes play a key role in the development of cerebral microcirculation. The exact role of pericytes in the neurovascular unit in the adult brain and during brain aging remains, however, elusive. Using adult viable pericyte-deficient mice, we show that pericyte loss leads to brain vascular damage by two parallel pathways: (1) reduction in brain microcirculation causing diminished brain capillary perfusion, cerebral blood flow, and cerebral blood flow responses to brain activation that ultimately mediates chronic perfusion stress and hypoxia, and (2) blood-brain barrier breakdown associated with brain accumulation of serum proteins and several vasculotoxic and/or neurotoxic macromolecules ultimately leading to secondary neuronal degenerative changes. We show that age-dependent vascular damage in pericyte-deficient mice precedes neuronal degenerative changes, learning and memory impairment, and the neuroinflammatory response. Thus, pericytes control key neurovascular functions that are necessary for proper neuronal structure and function, and pericyte loss results in a progressive age-dependent vascular-mediated neurodegeneration.
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Affiliation(s)
- Robert D. Bell
- Center for Neurodegenerative and Vascular Brain Disorders, Departments of Neurosurgery and Neurology, University of Rochester Medical Center, Rochester, New York, 14642
| | - Ethan A. Winkler
- Center for Neurodegenerative and Vascular Brain Disorders, Departments of Neurosurgery and Neurology, University of Rochester Medical Center, Rochester, New York, 14642
| | - Abhay P. Sagare
- Center for Neurodegenerative and Vascular Brain Disorders, Departments of Neurosurgery and Neurology, University of Rochester Medical Center, Rochester, New York, 14642
| | - Itender Singh
- Center for Neurodegenerative and Vascular Brain Disorders, Departments of Neurosurgery and Neurology, University of Rochester Medical Center, Rochester, New York, 14642
| | - Barb LaRue
- Center for Neurodegenerative and Vascular Brain Disorders, Departments of Neurosurgery and Neurology, University of Rochester Medical Center, Rochester, New York, 14642
| | - Rashid Deane
- Center for Neurodegenerative and Vascular Brain Disorders, Departments of Neurosurgery and Neurology, University of Rochester Medical Center, Rochester, New York, 14642
| | - Berislav V. Zlokovic
- Center for Neurodegenerative and Vascular Brain Disorders, Departments of Neurosurgery and Neurology, University of Rochester Medical Center, Rochester, New York, 14642
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111
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Quaegebeur A, Segura I, Carmeliet P. Pericytes: Blood-Brain Barrier Safeguards against Neurodegeneration? Neuron 2010; 68:321-3. [DOI: 10.1016/j.neuron.2010.10.024] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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112
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Pericytes are required for blood-brain barrier integrity during embryogenesis. Nature 2010; 468:562-6. [PMID: 20944625 DOI: 10.1038/nature09513] [Citation(s) in RCA: 1434] [Impact Index Per Article: 102.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 09/23/2010] [Indexed: 12/14/2022]
Abstract
Vascular endothelial cells in the central nervous system (CNS) form a barrier that restricts the movement of molecules and ions between the blood and the brain. This blood-brain barrier (BBB) is crucial to ensure proper neuronal function and protect the CNS from injury and disease. Transplantation studies have demonstrated that the BBB is not intrinsic to the endothelial cells, but is induced by interactions with the neural cells. Owing to the close spatial relationship between astrocytes and endothelial cells, it has been hypothesized that astrocytes induce this critical barrier postnatally, but the timing of BBB formation has been controversial. Here we demonstrate that the barrier is formed during embryogenesis as endothelial cells invade the CNS and pericytes are recruited to the nascent vessels, over a week before astrocyte generation. Analysing mice with null and hypomorphic alleles of Pdgfrb, which have defects in pericyte generation, we demonstrate that pericytes are necessary for the formation of the BBB, and that absolute pericyte coverage determines relative vascular permeability. We demonstrate that pericytes regulate functional aspects of the BBB, including the formation of tight junctions and vesicle trafficking in CNS endothelial cells. Pericytes do not induce BBB-specific gene expression in CNS endothelial cells, but inhibit the expression of molecules that increase vascular permeability and CNS immune cell infiltration. These data indicate that pericyte-endothelial cell interactions are critical to regulate the BBB during development, and disruption of these interactions may lead to BBB dysfunction and neuroinflammation during CNS injury and disease.
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113
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Endothelial-derived PDGF-BB and HB-EGF coordinately regulate pericyte recruitment during vasculogenic tube assembly and stabilization. Blood 2010; 116:4720-30. [PMID: 20739660 DOI: 10.1182/blood-2010-05-286872] [Citation(s) in RCA: 200] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Recently, we reported a novel system whereby human pericytes are recruited to endothelial cell (EC)-lined tubes in 3-dimensional (3D) extracellular matrices to stimulate vascular maturation including basement membrane matrix assembly. Through the use of this serum-free, defined system, we demonstrate that pericyte motility within 3D collagen matrices is dependent on the copresence of ECs. Using either soluble receptor traps consisting of the extracellular ligand-binding domains of platelet-derived growth factor receptor β, epidermal growth factor receptor (EGFR), and ErbB4 receptors or blocking antibodies directed to platelet-derived growth factor (PDGF)-BB, or heparin-binding EGF-like growth factor (HB-EGF), we show that both of these EC-derived ligands are required to control pericyte motility, proliferation, and recruitment along the EC tube ablumenal surface. Blockade of pericyte recruitment causes a lack of basement membrane matrix deposition and, concomitantly, increased vessel widths. Combined inhibition of PDGF-BB and HB-EGF-induced signaling in quail embryos leads to reduced pericyte recruitment to EC tubes, decreased basement membrane matrix deposition, increased vessel widths, and vascular hemorrhage phenotypes in vivo, in support of our findings in vitro. In conclusion, we report a dual role for EC-derived PDGF-BB and HB-EGF in controlling pericyte recruitment to EC-lined tubes during developmental vascularization events.
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114
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Winkler EA, Bell RD, Zlokovic BV. Pericyte-specific expression of PDGF beta receptor in mouse models with normal and deficient PDGF beta receptor signaling. Mol Neurodegener 2010; 5:32. [PMID: 20738866 PMCID: PMC2936891 DOI: 10.1186/1750-1326-5-32] [Citation(s) in RCA: 231] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Accepted: 08/25/2010] [Indexed: 11/10/2022] Open
Abstract
Background Pericytes are integral members of the neurovascular unit. Using mouse models lacking endothelial-secreted platelet derived growth factor-B (PDGF-B) or platelet derived growth factor receptor beta (PDGFRβ) on pericytes, it has been demonstrated that PDGF-B/PDGFRβ interactions mediate pericyte recruitment to the vessel wall in the embryonic brain regulating the development of the cerebral microcirculation and the blood-brain barrier (BBB). Relatively little is known, however, about the roles of PDGF-B/PDGFRβ interactions and pericytes in the adult brain in part due to a lack of adequate and/or properly characterized experimental models. To address whether genetic disruption of PDGFRβ signaling would result in a pericyte-specific insult in adult mice, we studied the pattern and cellular distribution of PDGFRβ expression in the brain in adult control mice and F7 mice that express two hypomorphic Pdgfrβ alleles containing seven point mutations in the cytoplasmic domain of PDGFRβ that impair downstream PDGFRβ receptor signaling. Results Using dual fluorescent in situ hybridization, immunofluorescent staining for different cell types in the neurovascular unit, and a fluorescent in situ proximity ligation assay to visualize molecular PDGF-B/PDGFRβ interactions on brain tissue sections, we show for the first time that PDGFRβ is exclusively expressed in pericytes, and not in neurons, astrocytes or endothelial cells, in the adult brain of control 129S1/SvlmJ mice. PDGFRβ co-localized only with well-established pericyte markers such as Chondroitin Sulfate Proteoglycan NG2 and the xLacZ4 transgenic reporter. We next confirm pericyte-specific PDGFRβ expression in the brains of F7 mutants and show that these mice are viable in spite of substantial 40-60% reductions in regional pericyte coverage of brain capillaries. Conclusions Our data show that PDGFRβ is exclusively expressed in pericytes in the adult 129S1/Sv1mJ and F7 mouse brain. Moreover, our findings suggest that genetic disruption of PDGFRβ signaling results in a pericyte-specific insult in adult F7 mutants and will not exert a primary effect on neurons because PDGFRβ is not expressed in neurons of the adult 129S1/SvlmJ and F7 mouse brain. Therefore, mouse models with normal and deficient PDGFRβ signaling on a 129S1/SvlmJ background may effectively be used to deduce the specific roles of pericytes in maintaining the cerebral microcirculation and BBB integrity in the adult and aging brain as well as during neurodegenerative and brain vascular disorders.
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Affiliation(s)
- Ethan A Winkler
- Center for Neurodegenerative and Vascular Brain Disorders, Department of Neurosurgery, University of Rochester, Rochester, NY, USA.
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115
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Wiens KM, Lee HL, Shimada H, Metcalf AE, Chao MY, Lien CL. Platelet-derived growth factor receptor beta is critical for zebrafish intersegmental vessel formation. PLoS One 2010; 5:e11324. [PMID: 20593033 PMCID: PMC2892519 DOI: 10.1371/journal.pone.0011324] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2009] [Accepted: 05/24/2010] [Indexed: 12/14/2022] Open
Abstract
Background Platelet-derived growth factor receptor β (PDGFRβ) is a tyrosine kinase receptor known to affect vascular development. The zebrafish is an excellent model to study specific regulators of vascular development, yet the role of PDGF signaling has not been determined in early zebrafish embryos. Furthermore, vascular mural cells, in which PDGFRβ functions cell autonomously in other systems, have not been identified in zebrafish embryos younger than 72 hours post fertilization. Methodology/Principal Findings In order to investigate the role of PDGFRβ in zebrafish vascular development, we cloned the highly conserved zebrafish homolog of PDGFRβ. We found that pdgfrβ is expressed in the hypochord, a developmental structure that is immediately dorsal to the dorsal aorta and potentially regulates blood vessel development in the zebrafish. Using a PDGFR tyrosine kinase inhibitor, a morpholino oligonucleotide specific to PDGFRβ, and a dominant negative PDGFRβ transgenic line, we found that PDGFRβ is necessary for angiogenesis of the intersegmental vessels. Significance/Conclusion Our data provide the first evidence that PDGFRβ signaling is required for zebrafish angiogenesis. We propose a novel mechanism for zebrafish PDGFRβ signaling that regulates vascular angiogenesis in the absence of mural cells.
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Affiliation(s)
- Katie M. Wiens
- Department of Surgery, Keck School of Medicine, University of Southern California and The Saban Research Institute of Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Hyuna L. Lee
- Department of Surgery, Keck School of Medicine, University of Southern California and The Saban Research Institute of Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Hiroyuki Shimada
- Department of Pathology, Keck School of Medicine, University of Southern California and The Saban Research Institute of Childrens Hospital Los Angeles, Los Angeles, California, United States of America
| | - Anthony E. Metcalf
- Department of Biology, California State University San Bernardino, San Bernardino, California, United States of America
| | - Michael Y. Chao
- Department of Biology, California State University San Bernardino, San Bernardino, California, United States of America
| | - Ching-Ling Lien
- Department of Surgery, Keck School of Medicine, University of Southern California and The Saban Research Institute of Childrens Hospital Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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116
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Richards OC, Raines SM, Attie AD. The role of blood vessels, endothelial cells, and vascular pericytes in insulin secretion and peripheral insulin action. Endocr Rev 2010; 31:343-63. [PMID: 20164242 PMCID: PMC3365844 DOI: 10.1210/er.2009-0035] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Accepted: 12/17/2009] [Indexed: 02/08/2023]
Abstract
The pathogenesis of type 2 diabetes is intimately intertwined with the vasculature. Insulin must efficiently enter the bloodstream from pancreatic beta-cells, circulate throughout the body, and efficiently exit the bloodstream to reach target tissues and mediate its effects. Defects in the vasculature of pancreatic islets can lead to diabetic phenotypes. Similarly, insulin resistance is accompanied by defects in the vasculature of skeletal muscle, which ultimately reduce the ability of insulin and nutrients to reach myocytes. An underappreciated participant in these processes is the vascular pericyte. Pericytes, the smooth muscle-like cells lining the outsides of blood vessels throughout the body, have not been directly implicated in insulin secretion or peripheral insulin delivery. Here, we review the role of the vasculature in insulin secretion, islet function, and peripheral insulin delivery, and highlight a potential role for the vascular pericyte in these processes.
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Affiliation(s)
- Oliver C Richards
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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117
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Angiogenesis inhibition in cancer therapy: platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) and their receptors: biological functions and role in malignancy. Recent Results Cancer Res 2010; 180:51-81. [PMID: 20033378 DOI: 10.1007/978-3-540-78281-0_5] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen in vitro and an angiogenic inducer in a variety of in vivo models. VEGF gene transcription is induced in particular in hypoxic cells. In developmental angiogenesis, the role of VEGF is demonstrated by the finding that the loss of a single VEGF allele results in defective vascularization and early embryonic lethality. Substantial evidence also implicates VEGF as a mediator of pathological angiogenesis. In situ hybridization studies demonstrate expression of VEGF mRNA in the majority of human tumors. Platelet-derived growth factor (PDGF) is mainly believed to be an important mitogen for connective tissue, and also has important roles during embryonal development. Its overexpression has been linked to different types of malignancies. Thus, it is important to understand the physiology of VEGF and PDGF and their receptors as well as their roles in malignancies in order to develop antiangiogenic strategies for the treatment of malignant disease.
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118
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Paye JMD, Phng LK, Lanahan AA, Gerhard H, Simons M. Synectin-dependent regulation of arterial maturation. Dev Dyn 2009; 238:604-10. [PMID: 19235722 DOI: 10.1002/dvdy.21880] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Synectin, a ubiquitously expressed PDZ scaffold protein, has been shown to be a key regulator in the formation of arterial vasculature. Examination of the retinal vasculature in synectin(-/-) mice demonstrated poor mural cell coverage of and attachment to the forming arterial tree, a defect reminiscent of retinal abnormalities observed in platelet derived growth factor (PDGF) -B(-/-) mice. Primary cultures of synectin(-/-) smooth muscle cells had normal expression of PDGFR-beta and migrated normally in response to PDGF-BB. However, expression of PDGF-BB protein, but not mRNA, was reduced in lysates from arterial, but not venous, primary synectin(-/-) endothelial cells (EC), that was restored by inhibition of proteosomal degradation. Transduction of synectin(-/-) and (+/+) EC with a bicistronic Pdgfb/gfp construct, resulted in comparable expression of green fluorescent protein in both EC populations while PDGF-BB expression was severely reduced in synectin(-/-) EC. Finally, synectin expression in synectin(-/-) arterial EC restored PDGF-BB protein levels. These results suggest that synectin deficiency results in increased degradation of PDGF-BB protein in arterial EC and, consequently, reduced recruitment of mural cells to newly forming arteries. This observation may explain the selective reduction in arterial morphogenesis observed in synectin knockout mice.
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Affiliation(s)
- Julie M D Paye
- Angiogenesis Research Center, Section of Cardiology, Dartmouth Medical School, Hanover, New Hampshire, USA
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119
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Turgeon B, Meloche S. Interpreting neonatal lethal phenotypes in mouse mutants: insights into gene function and human diseases. Physiol Rev 2009; 89:1-26. [PMID: 19126753 DOI: 10.1152/physrev.00040.2007] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The mouse represents the model of choice to study the biological function of mammalian genes through mutation of its genome. However, the biggest challenge of mouse geneticists remains the phenotypic analysis of mouse mutants. A survey of mouse mutant databases reveals a surprisingly high number of gene mutations leading to neonatal death. These genetically modified mouse mutants have been instrumental in elucidating gene function and have become important models of congenital human diseases. The main complication when phenotyping mutant mice dying during the neonatal period is the large spectrum of physiological systems whose defects can challenge neonatal survival. Here, we present a comprehensive review of gene mutations leading to neonatal lethality and discuss the impact of these mutations on the major physiological processes critical to mouse newborn survival: parturition, breathing, suckling, and homeostasis. Selected examples of mouse mutants are highlighted to illustrate how the precise identification of the timing and cause of death associated with these physiological processes allows for a more profound understanding of the underlying cellular and molecular defects. This review provides a guide for the analysis of neonatal lethal phenotypes in mutant mice that will be helpful for dissecting out the function of specific genes during mouse development.
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Affiliation(s)
- Benjamin Turgeon
- Department of Pharmacology and Molecular Biology, Université de Montréal, Montreal, Quebec, Canada
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120
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Argaw AT, Gurfein BT, Zhang Y, Zameer A, John GR. VEGF-mediated disruption of endothelial CLN-5 promotes blood-brain barrier breakdown. Proc Natl Acad Sci U S A 2009; 106:1977-82. [PMID: 19174516 PMCID: PMC2644149 DOI: 10.1073/pnas.0808698106] [Citation(s) in RCA: 475] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Indexed: 12/14/2022] Open
Abstract
Breakdown of the blood-brain barrier (BBB) is an early and significant event in CNS inflammation. Astrocyte-derived VEGF-A has been implicated in this response, but the underlying mechanisms remain unresolved. Here, we identify the endothelial transmembrane tight junction proteins claudin-5 (CLN-5) and occludin (OCLN) as targets of VEGF-A action. Down-regulation of CLN-5 and OCLN accompanied up-regulation of VEGF-A and correlated with BBB breakdown in experimental autoimmune encephalomyelitis, an animal model of CNS inflammatory disease. In cultures of brain microvascular endothelial cells, VEGF-A specifically down-regulated CLN-5 and OCLN protein and mRNA. In mouse cerebral cortex, microinjection of VEGF-A disrupted CLN-5 and OCLN and induced loss of barrier function. Importantly, functional studies revealed that expression of recombinant CLN-5 protected brain microvascular endothelial cell cultures from a VEGF-induced increase in paracellular permeability, whereas recombinant OCLN expressed under the same promoter was not protective. Previous studies have shown CLN-5 to be a key determinant of trans-endothelial resistance at the BBB. Our findings suggest that its down-regulation by VEGF-A constitutes a significant mechanism in BBB breakdown.
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Affiliation(s)
- Azeb Tadesse Argaw
- Corinne Goldsmith Dickinson Center for Multiple Sclerosis and Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029; and
| | - Blake T. Gurfein
- Corinne Goldsmith Dickinson Center for Multiple Sclerosis and Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029; and
| | - Yueting Zhang
- Corinne Goldsmith Dickinson Center for Multiple Sclerosis and Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029; and
| | - Andleeb Zameer
- Corinne Goldsmith Dickinson Center for Multiple Sclerosis and Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029; and
| | - Gareth R. John
- Corinne Goldsmith Dickinson Center for Multiple Sclerosis and Department of Neurology, Mount Sinai School of Medicine, New York, NY 10029; and
- Department of Pathology, Albert Einstein College of Medicine, Bronx, NY 10461
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121
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Mellgren AM, Smith CL, Olsen GS, Eskiocak B, Zhou B, Kazi MN, Ruiz FR, Pu WT, Tallquist MD. Platelet-derived growth factor receptor beta signaling is required for efficient epicardial cell migration and development of two distinct coronary vascular smooth muscle cell populations. Circ Res 2008; 103:1393-401. [PMID: 18948621 DOI: 10.1161/circresaha.108.176768] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The epicardium plays an essential role in coronary artery formation and myocardial development, but signals controlling the development and differentiation of this tissue are not well understood. To investigate the role of platelet-derived growth factor receptor (PDGFR)beta in development of epicardial-derived vascular smooth muscle cells (VSMCs), we examined PDGFRbeta(-/-) and PDGFRbeta epicardial mutant hearts. We found that PDGFRbeta(-/-) hearts failed to form dominant coronary vessels on the ventral heart surface, had a thinned myocardium, and completely lacked coronary VSMCs (cVSMCs). This constellation of defects was consistent with a primary defect in the epicardium. To verify that these defects were specific to epicardial derivatives, we generated mice with an epicardial deletion of PDGFRbeta that resulted in reduced cVSMCs distal to the aorta. The regional absence of cVSMCs suggested that cVSMCs could arise from 2 sources, epicardial and nonepicardial, and that both were dependent on PDGFRbeta. In the absence of PDGFRbeta signaling, epicardial cells adopted an irregular actin cytoskeleton, leading to aberrant migration of epicardial cells into the myocardium in vivo. In addition, PDGF receptor stimulation promoted epicardial cell migration, and PDGFRbeta-driven phosphoinositide 3'-kinase signaling was critical for this process. Our data demonstrate that PDGFRbeta is required for the formation of 2 distinct cVSMC populations and that loss of PDGFRbeta-PI3K signaling disrupts epicardial cell migration.
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MESH Headings
- Animals
- Cell Movement/physiology
- Cells, Cultured
- Coronary Vessels/cytology
- Coronary Vessels/metabolism
- Coronary Vessels/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiology
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/physiology
- Pericardium/cytology
- Pericardium/metabolism
- Pericardium/physiology
- Phosphatidylinositol 3-Kinases/deficiency
- Phosphatidylinositol 3-Kinases/physiology
- Receptor, Platelet-Derived Growth Factor beta/deficiency
- Receptor, Platelet-Derived Growth Factor beta/genetics
- Receptor, Platelet-Derived Growth Factor beta/physiology
- Signal Transduction/genetics
- Signal Transduction/physiology
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Affiliation(s)
- Amy M Mellgren
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA
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122
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Abstract
Platelet-derived growth factors (PDGFs) and their receptors (PDGFRs) have served as prototypes for growth factor and receptor tyrosine kinase function for more than 25 years. Studies of PDGFs and PDGFRs in animal development have revealed roles for PDGFR-alpha signaling in gastrulation and in the development of the cranial and cardiac neural crest, gonads, lung, intestine, skin, CNS, and skeleton. Similarly, roles for PDGFR-beta signaling have been established in blood vessel formation and early hematopoiesis. PDGF signaling is implicated in a range of diseases. Autocrine activation of PDGF signaling pathways is involved in certain gliomas, sarcomas, and leukemias. Paracrine PDGF signaling is commonly observed in epithelial cancers, where it triggers stromal recruitment and may be involved in epithelial-mesenchymal transition, thereby affecting tumor growth, angiogenesis, invasion, and metastasis. PDGFs drive pathological mesenchymal responses in vascular disorders such as atherosclerosis, restenosis, pulmonary hypertension, and retinal diseases, as well as in fibrotic diseases, including pulmonary fibrosis, liver cirrhosis, scleroderma, glomerulosclerosis, and cardiac fibrosis. We review basic aspects of the PDGF ligands and receptors, their developmental and pathological functions, principles of their pharmacological inhibition, and results using PDGF pathway-inhibitory or stimulatory drugs in preclinical and clinical contexts.
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123
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Pickett EA, Olsen GS, Tallquist MD. Disruption of PDGFRalpha-initiated PI3K activation and migration of somite derivatives leads to spina bifida. Development 2008; 135:589-98. [PMID: 18192285 DOI: 10.1242/dev.013763] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Spina bifida, or failure of the vertebrae to close at the midline, is a common congenital malformation in humans that is often synonymous with neural tube defects (NTDs). However, it is likely that other etiologies exist. Genetic disruption of platelet-derived growth factor receptor (PDGFR) alpha results in spina bifida, but the underlying mechanism has not been identified. To elucidate the cause of this birth defect in PDGFRalpha mutant embryos, we examined the developmental processes involved in vertebrae formation. Exposure of chick embryos to the PDGFR inhibitor imatinib mesylate resulted in spina bifida in the absence of NTDs. We next examined embryos with a tissue-specific deletion of the receptor. We found that loss of the receptor from chondrocytes did not recapitulate the spina bifida phenotype. By contrast, loss of the receptor from all sclerotome and dermatome derivatives or disruption of PDGFRalpha-driven phosphatidyl-inositol 3' kinase (PI3K) activity resulted in spina bifida. Furthermore, we identified a migration defect in the sclerotome as the cause of the abnormal vertebral development. We found that primary cells from these mice exhibited defects in PAK1 activation and paxillin localization. Taken together, these results indicate that PDGFRalpha downstream effectors, especially PI3K, are essential for cell migration of a somite-derived dorsal mesenchyme and disruption of receptor signaling in these cells leads to spina bifida.
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Affiliation(s)
- Elizabeth A Pickett
- Department of Molecular Biology, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
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124
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Fibroblast growth factor receptor 2 phosphorylation on serine 779 couples to 14-3-3 and regulates cell survival and proliferation. Mol Cell Biol 2008; 28:3372-85. [PMID: 18332103 DOI: 10.1128/mcb.01837-07] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The fibroblast growth factors (FGFs) exert their diverse (or pleiotropic) biological responses through the binding and activation of specific cell surface receptors (FGFRs). While FGFRs are known to initiate intracellular signaling through receptor tyrosine phosphorylation, the precise mechanisms by which the FGFRs regulate pleiotropic biological responses remain unclear. We now identify a new mechanism by which FGFR2 is able to regulate intracellular signaling and cellular responses. We show that FGFR2 is phosphorylated on serine 779 (S779) in response to FGF2. S779, which lies adjacent to the phospholipase Cgamma binding site at Y766, provides a docking site for the 14-3-3 phosphoserine-binding proteins and is essential for the full activation of the phosphatidylinositol 3-kinase and Ras/mitogen-activated protein kinase pathways. Furthermore, S779 signaling is essential for promoting cell survival and proliferation in both Ba/F3 cells and BALB/c 3T3 fibroblasts. This new mode of FGFR2 phosphoserine signaling via the 14-3-3 proteins may provide an increased repertoire of signaling outputs to allow the regulation of pleiotropic biological responses. In this regard, we have identified conserved putative phosphotyrosine/phosphoserine motifs in the cytoplasmic domains of diverse cell surface receptors, suggesting that they may perform important functional roles beyond the FGFRs.
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125
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Abstract
This chapter summarizes experimental techniques used to study coronary vessel development from its origins in the proepicardium (PE) to the final assembled network of arteries, veins, and capillaries present in the mature heart. Methods are described for microdissection and culture of the PE and embryonic epicardial cells, isolation of total RNA from single PE primordia and analysis by RT-PCR, imaging of the epicardium and coronary vessels by whole-mount confocal microscopy and by scanning electron microscopy, and the preparation of coronary vascular corrosion casts to visualize the entire coronary artery network structure. These techniques form the basic tools to study the cellular and molecular pathways that guide development and remodeling of coronary vessels.
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Affiliation(s)
- Xiu Rong Dong
- Carolina Cardiovascular Biology Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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126
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127
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Gerhardt H, Semb H. Pericytes: gatekeepers in tumour cell metastasis? J Mol Med (Berl) 2007; 86:135-44. [PMID: 17891366 DOI: 10.1007/s00109-007-0258-2] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 07/23/2007] [Accepted: 08/17/2007] [Indexed: 02/08/2023]
Abstract
Tumour cells use two major routes to spread during metastasis, e.g. lymph vessels and blood vessels within or surrounding the primary tumour. The growth rate of the primary tumour often correlates with the quantity of new blood vessels that form within the tumour. However, qualitative abnormalities of the tumour vasculature profoundly affect the perfusion of the primary tumour and the escape of tumour cells into the circulation. In this paper, we review recent evidence for a novel role of the supporting mural cells in limiting blood-borne metastasis.
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Affiliation(s)
- Holger Gerhardt
- Vascular Biology Laboratory, London Research Institute-Cancer Research UK, 44 Lincoln's Inn Fields, London, WC2A 3PX, UK.
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128
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Singh PK, Wen Y, Swanson BJ, Shanmugam K, Kazlauskas A, Cerny RL, Gendler SJ, Hollingsworth MA. Platelet-derived growth factor receptor beta-mediated phosphorylation of MUC1 enhances invasiveness in pancreatic adenocarcinoma cells. Cancer Res 2007; 67:5201-10. [PMID: 17545600 DOI: 10.1158/0008-5472.can-06-4647] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
MUC1 is a heterodimeric transmembrane glycoprotein that is overexpressed and aberrantly glycosylated in ductal adenocarcinomas. Differential phosphorylation of the MUC1 cytoplasmic tail (MUC1CT) has been associated with signaling events that influence the proliferation and metastasis of cancer cells. We identified a novel tyrosine phosphorylation site (HGRYVPP) in the MUC1CT by mass spectrometric analysis of MUC1 from human pancreatic adenocarcinoma cell lines. Analyses in vitro and in vivo showed that platelet-derived growth factor receptor beta (PDGFRbeta) catalyzed phosphorylation of this site and of tyrosine in the RDTYHPM site. Stimulation of S2-013.MUC1F cells with PDGF-BB increased nuclear colocalization of MUC1CT and beta-catenin. PDGF-BB stimulation had no significant effect on cell proliferation rate; however, it enhanced invasion in vitro through Matrigel and in vivo tumor growth and metastases. Invasive properties of the cells were significantly altered on expression of phosphorylation-abrogating or phosphorylation-mimicking mutations at these sites. We propose that interactions of MUC1 and PDGFRbeta induce signal transduction events that influence the metastatic properties of pancreatic adenocarcinoma.
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Affiliation(s)
- Pankaj K Singh
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska 68198-6805, USA
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129
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Abstract
Blood vessels and lymphatic vessels form extensive networks that are essential for the transport of fluids, gases, macromolecules and cells within the large and complex bodies of vertebrates. Both of these vascular structures are lined with endothelial cells that integrate functionally into different organs, acquire tissue-specific specialization and retain plasticity; thereby, they permit growth during tissue repair or in disease settings. The angiogenic growth of blood vessels and lymphatic vessels coordinates several biological processes such as cell proliferation, guided migration, differentiation and cell-cell communication.
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Affiliation(s)
- Ralf H Adams
- Vascular Development Laboratory, Cancer Research UK London Research Institute, London WC2A 3PX, UK.
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130
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Abramsson A, Kurup S, Busse M, Yamada S, Lindblom P, Schallmeiner E, Stenzel D, Sauvaget D, Ledin J, Ringvall M, Landegren U, Kjellén L, Bondjers G, Li JP, Lindahl U, Spillmann D, Betsholtz C, Gerhardt H. Defective N-sulfation of heparan sulfate proteoglycans limits PDGF-BB binding and pericyte recruitment in vascular development. Genes Dev 2007; 21:316-31. [PMID: 17289920 PMCID: PMC1785125 DOI: 10.1101/gad.398207] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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 beta (PDGFRbeta) signaling, whereas the detailed sequence of monosaccharide and sulfate residues does not appear to be important for this interaction.
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Affiliation(s)
- Alexandra Abramsson
- Department of Medical Biochemistry and Biophysics, Division of Matrix Biology, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Sindhulakshmi Kurup
- Department of Medical Biochemistry and Microbiology, University of Uppsala, SE-751 23 Uppsala, Sweden
| | - Marta Busse
- Vascular Biology Laboratory, Cancer Research UK, Lincoln’s Inn Fields Laboratories, London WC 2A 3PX, United Kingdom
| | - Shuhei Yamada
- Department of Medical Biochemistry and Microbiology, University of Uppsala, SE-751 23 Uppsala, Sweden
| | - Per Lindblom
- Vascular Biology Laboratory, Cancer Research UK, Lincoln’s Inn Fields Laboratories, London WC 2A 3PX, United Kingdom
| | - Edith Schallmeiner
- Department of Genetics and Pathology, Rudbeck Laboratory, SE-751 85 Uppsala, Sweden
| | - Denise Stenzel
- Vascular Biology Laboratory, Cancer Research UK, Lincoln’s Inn Fields Laboratories, London WC 2A 3PX, United Kingdom
| | - Dominique Sauvaget
- Vascular Biology Laboratory, Cancer Research UK, Lincoln’s Inn Fields Laboratories, London WC 2A 3PX, United Kingdom
| | - Johan Ledin
- Department of Medical Biochemistry and Microbiology, University of Uppsala, SE-751 23 Uppsala, Sweden
| | - Maria Ringvall
- Department of Medical Biochemistry and Microbiology, University of Uppsala, SE-751 23 Uppsala, Sweden
| | - Ulf Landegren
- Department of Genetics and Pathology, Rudbeck Laboratory, SE-751 85 Uppsala, Sweden
| | - Lena Kjellén
- Department of Medical Biochemistry and Microbiology, University of Uppsala, SE-751 23 Uppsala, Sweden
| | - Göran Bondjers
- Wallenberg Laboratory for Cardiovascular Research, Sahlgrenska Academy, Göteborg University, SE-413 45 Gothenburg, Sweden
| | - Jin-ping Li
- Department of Medical Biochemistry and Microbiology, University of Uppsala, SE-751 23 Uppsala, Sweden
| | - Ulf Lindahl
- Department of Medical Biochemistry and Microbiology, University of Uppsala, SE-751 23 Uppsala, Sweden
| | - Dorothe Spillmann
- Department of Medical Biochemistry and Microbiology, University of Uppsala, SE-751 23 Uppsala, Sweden
| | - Christer Betsholtz
- Department of Medical Biochemistry and Biophysics, Division of Matrix Biology, Karolinska Institute, SE-171 77 Stockholm, Sweden
| | - Holger Gerhardt
- Vascular Biology Laboratory, Cancer Research UK, Lincoln’s Inn Fields Laboratories, London WC 2A 3PX, United Kingdom
- Corresponding author.E-MAIL ; FAX 44-207-269-3417
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131
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Jiang R, Bush JO, Lidral AC. Development of the upper lip: morphogenetic and molecular mechanisms. Dev Dyn 2006; 235:1152-66. [PMID: 16292776 PMCID: PMC2562450 DOI: 10.1002/dvdy.20646] [Citation(s) in RCA: 210] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The vertebrate upper lip forms from initially freely projecting maxillary, medial nasal, and lateral nasal prominences at the rostral and lateral boundaries of the primitive oral cavity. These facial prominences arise during early embryogenesis from ventrally migrating neural crest cells in combination with the head ectoderm and mesoderm and undergo directed growth and expansion around the nasal pits to actively fuse with each other. Initial fusion is between lateral and medial nasal processes and is followed by fusion between maxillary and medial nasal processes. Fusion between these prominences involves active epithelial filopodial and adhering interactions as well as programmed cell death. Slight defects in growth and patterning of the facial mesenchyme or epithelial fusion result in cleft lip with or without cleft palate, the most common and disfiguring craniofacial birth defect. Recent studies of craniofacial development in animal models have identified components of several major signaling pathways, including Bmp, Fgf, Shh, and Wnt signaling, that are critical for proper midfacial morphogenesis and/or lip fusion. There is also accumulating evidence that these signaling pathways cross-regulate genetically as well as crosstalk intracellularly to control cell proliferation and tissue patterning. This review will summarize the current understanding of the basic morphogenetic processes and molecular mechanisms underlying upper lip development and discuss the complex interactions of the various signaling pathways and challenges for understanding cleft lip pathogenesis.
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Affiliation(s)
- Rulang Jiang
- Center for Oral Biology and Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA.
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132
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Ma J, Wang Q, Fei T, Han JDJ, Chen YG. MCP-1 mediates TGF-beta-induced angiogenesis by stimulating vascular smooth muscle cell migration. Blood 2006; 109:987-94. [PMID: 17032917 DOI: 10.1182/blood-2006-07-036400] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transforming growth factor-beta (TGF-beta) and its signaling mediators play crucial roles in vascular formation. Our previous microarray analysis identified monocyte chemoattractant protein-1 (MCP-1) as a TGF-beta target gene in endothelial cells (ECs). Here, we report that MCP-1 mediates the angiogenic effect of TGF-beta by recruiting vascular smooth muscle cells (VSMCs) and mesenchymal cells toward ECs. By using a chick chorioallantoic membrane assay, we show that TGF-beta promotes the formation of new blood vessels and this promotion is attenuated when MCP-1 activity is blocked by its neutralizing antibody. Wound healing and transwell assays established that MCP-1 functions as a chemoattractant to stimulate migration of VSMCs and mesenchymal 10T1/2 cells toward ECs. Furthermore, the conditioned media from TGF-beta-treated ECs stimulate VSMC migration, and inhibition of MCP-1 activity attenuates TGF-beta-induced VSMC migration toward ECs. Finally, we found that MCP-1 is a direct gene target of TGF-beta via Smad3/4. Taken together, our findings suggest that MCP-1 mediates TGF-beta-stimulated angiogenesis by enhancing migration of mural cells toward ECs and thus promoting the maturation of new blood vessels.
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Affiliation(s)
- Jing Ma
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, China
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133
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Hoch RV, Soriano P. Context-specific requirements for Fgfr1 signaling through Frs2 and Frs3 during mouse development. Development 2006; 133:663-73. [PMID: 16421190 DOI: 10.1242/dev.02242] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Fibroblast growth factor receptor 1 (Fgfr1) plays pleiotropic roles during embryonic development, but the mechanisms by which this receptor signals in vivo have not previously been elucidated. Biochemical studies have implicated Fgf receptor-specific substrates (Frs2, Frs3) as the principal mediators of Fgfr1 signal transduction to the MAPK and PI3K pathways. To determine the developmental requirements for Fgfr1-Frs signaling, we generated mice (Fgfr1ΔFrs/ΔFrs) in which the Frs2/3-binding site on Fgfr1 is deleted. Fgfr1ΔFrs/ΔFrs embryos die during late embryogenesis, and exhibit defects in neural tube closure and in the development of the tail bud and pharyngeal arches. However, the mutant receptor is able to drive Fgfr1 functions during gastrulation and somitogenesis, and drives normal MAPK responses to Fgf. These findings indicate that Fgfr1 uses distinct signal transduction mechanisms in different developmental contexts, and that some essential functions of this receptor are mediated by Frs-independent signaling.
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Affiliation(s)
- Renée V Hoch
- Program in Developmental Biology, Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109, USA
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134
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Xian X, Håkansson J, Ståhlberg A, Lindblom P, Betsholtz C, Gerhardt H, Semb H. Pericytes limit tumor cell metastasis. J Clin Invest 2006; 116:642-51. [PMID: 16470244 PMCID: PMC1361347 DOI: 10.1172/jci25705] [Citation(s) in RCA: 272] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Accepted: 12/06/2005] [Indexed: 01/13/2023] Open
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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135
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Tang J, Kozaki K, Farr AG, Martin PJ, Lindahl P, Betsholtz C, Raines EW. The absence of platelet-derived growth factor-B in circulating cells promotes immune and inflammatory responses in atherosclerosis-prone ApoE-/- mice. THE AMERICAN JOURNAL OF PATHOLOGY 2005; 167:901-12. [PMID: 16127167 PMCID: PMC1698743 DOI: 10.1016/s0002-9440(10)62061-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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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Affiliation(s)
- Jingjing Tang
- Department of Pathology, University Of Washington, Seattle, WA 98104-2499, USA
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136
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Abstract
Interactions between endothelial cells and mural cells (pericytes and vascular smooth muscle cells) in the blood vessel wall have recently come into focus as central processes in the regulation of vascular formation, stabilization, remodeling, and function. Failure of the interactions between the 2 cell types, as seen in numerous genetic mouse models, results in severe and often lethal cardiovascular defects. Abnormal interactions between the 2 cell types are also implicated in a number of human pathological conditions, including tumor angiogenesis, diabetic microangiopathy, ectopic tissue calcification, and stroke and dementia syndrome CADASIL. In the present review, we summarize current knowledge concerning the identity, characteristics, diversity, ontogeny, and plasticity of pericytes. We focus on the advancement in recent years of the understanding of intercellular communication between endothelial and mural cells with a focus on transforming growth factor beta, angiopoietins, platelet-derived growth factor, spingosine-1-phosphate, and Notch ligands and their respective receptors. We finally highlight recent important data contributing to the understanding of the role of pericytes in tumor angiogenesis, diabetic retinopathy, and hereditary lymphedema.
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Affiliation(s)
- Annika Armulik
- Division of Matrix Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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137
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Banfi A, von Degenfeld G, Blau HM. Critical role of microenvironmental factors in angiogenesis. Curr Atheroscler Rep 2005; 7:227-34. [PMID: 15811258 DOI: 10.1007/s11883-005-0011-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Therapeutic angiogenesis, which entails the induction of new blood vessels by the delivery of angiogenic growth factors, is a highly attractive approach to the treatment of ischemic diseases. However, it is becoming increasingly clear that this is not easily achieved, as the effects of angiogenic growth factors can differ markedly depending on the timing of their expression, on the shape of the concentration gradients they form in vivo, and the inter-actions between endothelial cells and pericytes they induce. In fact, the same dose of vascular endothelial growth factor can induce stable, nonleaky, pericyte-covered normal capillaries or aberrant vascular structures that develop into hemangiomas. This difference in outcome can be due solely to the spatial characteristics of the delivery method. If delivery allows a homogeneous spatial distribution of VEGF in the microenvironment around each producing cell, angiogenesis can be therapeutic, whereas if the total dose is the average of diverse spatial levels, aberrant angiogenesis cannot be avoided. To achieve therapeutic angiogenesis, a means of regulating the microenvironmental levels of angiogenic factors will be critical to the generation of effective new treatment strategies.
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Affiliation(s)
- Andrea Banfi
- Department of Research, Basel University Hospital, Hebelstrasse 20, 4031 Basel, Switzerland.
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138
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Povelones M, Howes R, Fish M, Nusse R. Genetic evidence that Drosophila frizzled controls planar cell polarity and Armadillo signaling by a common mechanism. Genetics 2005; 171:1643-54. [PMID: 16085697 PMCID: PMC1456092 DOI: 10.1534/genetics.105.045245] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The frizzled (fz) gene in Drosophila controls two distinct signaling pathways: it directs the planar cell polarization (PCP) of epithelia and it regulates cell fate decisions through Armadillo (Arm) by acting as a receptor for the Wnt protein Wingless (Wg). With the exception of dishevelled (dsh), the genes functioning in these two pathways are distinct. We have taken a genetic approach, based on a series of new and existing fz alleles, for identifying individual amino acids required for PCP or Arm signaling. For each allele, we have attempted to quantify the strength of signaling by phenotypic measurements. For PCP signaling, the defect was measured by counting the number of cells secreting multiple hairs in the wing. We then examined each allele for its ability to participate in Arm signaling by the rescue of fz mutant embryos with maternally provided fz function. For both PCP and Arm signaling we observed a broad range of phenotypes, but for every allele there is a strong correlation between its phenotypic strength in each pathway. Therefore, even though the PCP and Arm signaling pathways are genetically distinct, the set of signaling-defective fz alleles affected both pathways to a similar extent. This suggests that fz controls these two different signaling activities by a common mechanism. In addition, this screen yielded a set of missense mutations that identify amino acids specifically required for fz signaling function.
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Affiliation(s)
- Michael Povelones
- Howard Hughes Medical Institute, Department of Developmental Biology, Beckman Center, Stanford University School of Medicine, Stanford, CA 94305, USA
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139
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Howson KM, Aplin AC, Gelati M, Alessandri G, Parati EA, Nicosia RF. The postnatal rat aorta contains pericyte progenitor cells that form spheroidal colonies in suspension culture. Am J Physiol Cell Physiol 2005; 289:C1396-407. [PMID: 16079185 DOI: 10.1152/ajpcell.00168.2005] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pericytes play an important role in modulating angiogenesis, but the origin of these cells is poorly understood. To evaluate whether the mature vessel wall contains pericyte progenitor cells, nonendothelial mesenchymal cells isolated from the rat aorta were cultured in a serum-free medium optimized for stem cells. This method led to the isolation of anchorage-independent cells that proliferated slowly in suspension, forming spheroidal colonies. This process required basic fibroblast growth factor (bFGF) in the culture medium, because bFGF withdrawal caused the cells to attach to the culture dish and irreversibly lose their capacity to grow in suspension. Immunocytochemistry and RT-PCR analysis revealed the expression of the precursor cell markers CD34 and Tie-2 and the absence of endothelial cell markers (CD31 and endothelial nitric oxide synthase, eNOS) and smooth muscle cell markers (alpha-smooth muscle actin, alpha-SMA). In addition, spheroid-forming cells were positive for NG2, nestin, PDGF receptor (PDGFR)-alpha, and PDGFR-beta. Upon exposure to serum, these cells lost CD34 expression, acquired alpha-SMA, and attached to the culture dish. Returning these cells to serum-free medium failed to restore their original spheroid phenotype, suggesting terminal differentiation. When embedded in collagen gels, spheroid-forming cells rapidly migrated in response to PDGF-BB and became dendritic. Spheroid-forming cells cocultured in collagen with angiogenic outgrowths of rat aorta or isolated endothelial cells transformed into pericytes. These results demonstrate that the rat aorta contains primitive mesenchymal cells capable of pericyte differentiation. These immature cells may represent an important source of pericytes during angiogenesis in physiological and pathological processes. They may also provide a convenient supply of mural cells for vascular bioengineering applications.
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Affiliation(s)
- K M Howson
- Division of Pathology and Laboratory Medicine (S-113-Lab Veterans Affairs Puget Sound Health Care System, 1660 South Columbian Way, Seattle, WA 98108, USA
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140
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Lehti K, Allen E, Birkedal-Hansen H, Holmbeck K, Miyake Y, Chun TH, Weiss SJ. An MT1-MMP-PDGF receptor-beta axis regulates mural cell investment of the microvasculature. Genes Dev 2005; 19:979-91. [PMID: 15805464 PMCID: PMC1080136 DOI: 10.1101/gad.1294605] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Platelet-derived growth factor (PDGF)/PDGFRbeta-dependent investment of the vascular endothelium by mural cells (i.e., pericytes and vascular smooth muscle cells; VSMCs) is critical for normal vessel wall structure and function. In the developing vasculature, mural cell recruitment is associated with the functionally undefined expression of the type I transmembrane proteinase, membrane-type 1 matrix metalloproteinase (MT1-MMP). In this paper, using VSMCs and tissues isolated from gene-targeted mice, we identify MT1-MMP as a PDGF-B-selective regulator of PDGFRbeta-dependent signal transduction and mural cell function. In VSMCs, catalytically active MT1-MMP associates with PDGFRbeta in membrane complexes that support the efficient induction of mitogenic signaling by PDGF-B in a matrix metalloproteinase inhibitor-sensitive fashion. In contrast, MT1-MMP-deficient VSMCs display PDGF-B-selective defects in chemotaxis and proliferation as well as ERK1/2 and Akt activation that can be rescued in tandem fashion following retroviral transduction with the wild-type protease. Consistent with these in vitro findings, MT1-MMP-deficient brain tissues display a marked reduction in mural cell density as well as abnormal vessel wall morphology similar to that reported in mice expressing PDGF-B or PDGFRbeta hypomorphic alleles. Together, these data identify MT1-MMP as a novel proteolytic modifier of PDGF-B/PDGFRbeta signal transduction that cooperatively regulates vessel wall architecture in vivo.
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Affiliation(s)
- Kaisa Lehti
- Division of Molecular Medicine and Genetics, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA
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141
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Buch S, Sui Y, Dhillon N, Potula R, Zien C, Pinson D, Li S, Dhillon S, Nicolay B, Sidelnik A, Li C, Villinger T, Bisarriya K, Narayan O. Investigations on four host response factors whose expression is enhanced in X4 SHIV encephalitis. J Neuroimmunol 2005; 157:71-80. [PMID: 15579283 DOI: 10.1016/j.jneuroim.2004.08.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2004] [Indexed: 11/22/2022]
Abstract
HIV encephalopathy, one of the major complications of HIV infection, involves productive virus replication in macrophages in the brain in association with heightened expression of several host response factors. One or more of these factors are thought to be the cause of the degenerative changes in neurons in the brain. Macaques infected with SIV and SHIV viruses have provided excellent working models for studying mechanisms of the human disease. Although HIV encephalopathy is primarily associated with CCR5-utilizing viruses, our findings have shown that CXCR4-utilizing SHIVs were also capable of causing the syndrome in rhesus macaques. In SHIV-infected macaques, approximately 30% of the animals developed encephalitis. In order to understand the factors leading to end-stage encephalitis, we performed microarray analyses on brains of encephalitic and non-encephalitic-infected macaques, and found pronounced enhancement of expression of interleukin-4, platelet-derived growth factor-B chain, monocyte chemoattractant protein-1 and CXCL10 in the brains of the encephalitic animals. This review discusses the role of each of these factors in mediating SHIV encephalitis.
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Affiliation(s)
- Shilpa Buch
- Department of Microbiology, Immunology and Molecular Genetics, Marion Merrell Dow Laboratory of Viral Pathogenesis, 5000 Wahl Hall East, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160, USA.
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142
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Abstract
Since its discovery over three decades ago, platelet-derived growth factor (PDGF) has been a model system for learning how growth factors regulate biological processes. For the first several decades investigators used cells grown in tissue culture. More recently, PDGF signaling has also been investigated in mice. This review outlines the advances in these two systems, and highlights some of the directions for future investigation.
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Affiliation(s)
- Michelle Tallquist
- Deptartment of Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390-9046, USA
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143
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Betsholtz C. Insight into the physiological functions of PDGF through genetic studies in mice. Cytokine Growth Factor Rev 2005; 15:215-28. [PMID: 15207813 DOI: 10.1016/j.cytogfr.2004.03.005] [Citation(s) in RCA: 265] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Genetic analyses in mice have contributed significantly to the understanding of the physiological functions of platelet-derived growth factors (PDGFs) and their receptors. Phenotypic analyses of gene knockouts of PDGF-A, PDGF-B, PDGF alpha-receptors (PDGFRalpha) and beta-receptors (PDGFRbeta) have shown that these ligands and receptors play major roles during embryonic development. Conditional and subtle mutations in the same genes and analysis of chimeric mice have provided additional information about the roles of these genes in postnatal development. Transgenic over-expression studies have also demonstrated that PDGF ligands are capable of inducing pathological cell proliferation in a number of different organs. The present review summarizes these findings and discusses their implications for mammalian development and disease.
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Affiliation(s)
- Christer Betsholtz
- Department of Medical Biochemistry, University of Göteborg, P.O. Box 440, SE 405 30 Göteborg, Sweden.
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144
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Bjarnegård M, Enge M, Norlin J, Gustafsdottir S, Fredriksson S, Abramsson A, Takemoto M, Gustafsson E, Fässler R, Betsholtz C. Endothelium-specific ablation of PDGFB leads to pericyte loss and glomerular, cardiac and placental abnormalities. Development 2004; 131:1847-57. [PMID: 15084468 DOI: 10.1242/dev.01080] [Citation(s) in RCA: 268] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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.
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Affiliation(s)
- Mattias Bjarnegård
- Department of Medical Biochemistry, Göteborg University, PO Box 440, SE 405 30 Göteborg, Sweden
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145
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Affiliation(s)
- Mark W Majesky
- Departments of Medicine and Genetics, Carolina Cardiovascular Biology Center, University of North Carolina, Chapel Hill, North Carolina 27599, USA
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