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Park YS, Cho JH, Kim IH, Cho GS, Cho JH, Park JH, Ahn JH, Chen BH, Shin BN, Shin MC, Tae HJ, Cho YS, Lee YL, Kim YM, Won MH, Lee JC. Effects of ischemic preconditioning on VEGF and pFlk-1 immunoreactivities in the gerbil ischemic hippocampus after transient cerebral ischemia. J Neurol Sci 2014; 347:179-87. [PMID: 25300771 DOI: 10.1016/j.jns.2014.09.044] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 09/01/2014] [Accepted: 09/23/2014] [Indexed: 01/19/2023]
Abstract
Ischemia preconditioning (IPC) displays an important adaptation of the CNS to sub-lethal ischemia. In the present study, we examined the effect of IPC on immunoreactivities of VEGF-, and phospho-Flk-1 (pFlk-1) following transient cerebral ischemia in gerbils. The animals were randomly assigned to four groups (sham-operated-group, ischemia-operated-group, IPC plus (+) sham-operated-group, and IPC+ischemia-operated-group). IPC was induced by subjecting gerbils to 2 min of ischemia followed by 1 day of recovery. In the ischemia-operated-group, a significant loss of neurons was observed in the stratum pyramidale (SP) of the hippocampal CA1 region (CA1) alone 5 days after ischemia-reperfusion, however, in all the IPC+ischemia-operated-groups, pyramidal neurons in the SP were well protected. In immunohistochemical study, VEGF immunoreactivity in the ischemia-operated-group was increased in the SP at 1 day post-ischemia and decreased with time. Five days after ischemia-reperfusion, strong VEGF immunoreactivity was found in non-pyramidal cells, which were identified as pericytes, in the stratum oriens (SO) and radiatum (SR). In the IPC+sham-operated- and IPC+ischemia-operated-groups, VEGF immunoreactivity was significantly increased in the SP. pFlk-1 immunoreactivity in the sham-operated- and ischemia-operated-groups was hardly found in the SP, and, from 2 days post-ischemia, pFlk-1 immunoreactivity was strongly increased in non-pyramidal cells, which were identified as pericytes. In the IPC+sham-operated-group, pFlk-1 immunoreactivity was significantly increased in both pyramidal and non-pyramidal cells; in the IPC+ischemia-operated-groups, the similar pattern of VEGF immunoreactivity was found in the ischemic CA1, although the VEGF immunoreactivity was strong in non-pyramidal cells at 5 days post-ischemia. In brief, our findings show that IPC dramatically augmented the induction of VEGF and pFlk-1 immunoreactivity in the pyramidal cells of the CA1 after ischemia-reperfusion, and these findings suggest that the increases of VEGF and Flk-1 expressions may be necessary for neurons to survive from transient ischemic damage.
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Affiliation(s)
- Yoo Seok Park
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea; Department of Emergency Medicine, Yonsei University College of Medicine, Seoul 120-752, South Korea
| | - Jun Hwi Cho
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea
| | - In Hye Kim
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea
| | - Geum-Sil Cho
- Department of Neuroscience, College of Medicine, Korea University, Seoul 136-705, South Korea
| | - Jeong-Hwi Cho
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea
| | - Joon Ha Park
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea
| | - Ji Hyeon Ahn
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea
| | - Bai Hui Chen
- Department of Physiology, College of Medicine and Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon 200-702, South Korea
| | - Bich-Na Shin
- Department of Physiology, College of Medicine and Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon 200-702, South Korea
| | - Myoung Cheol Shin
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea
| | - Hyun-Jin Tae
- Department of Biomedical Science and Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 200-702, South Korea
| | - Young Shin Cho
- Department of Emergency Medicine, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea; Department of Emergency Medicine, Seoul Hospital, College of Medicine, Sooncheonhyang University, Seoul 140-743, South Korea
| | - Yun Lyul Lee
- Department of Physiology, College of Medicine and Institute of Neurodegeneration and Neuroregeneration, Hallym University, Chuncheon 200-702, South Korea
| | - Young-Myeong Kim
- Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea
| | - Moo-Ho Won
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea.
| | - Jae-Chul Lee
- Department of Neurobiology, School of Medicine, Kangwon National University, Chuncheon 200-701, South Korea.
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52
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Lehmann J, Härtig W, Seidel A, Füldner C, Hobohm C, Grosche J, Krueger M, Michalski D. Inflammatory cell recruitment after experimental thromboembolic stroke in rats. Neuroscience 2014; 279:139-54. [DOI: 10.1016/j.neuroscience.2014.08.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 07/28/2014] [Accepted: 08/17/2014] [Indexed: 10/24/2022]
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Özen I, Deierborg T, Miharada K, Padel T, Englund E, Genové G, Paul G. Brain pericytes acquire a microglial phenotype after stroke. Acta Neuropathol 2014; 128:381-96. [PMID: 24848101 PMCID: PMC4131168 DOI: 10.1007/s00401-014-1295-x] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 05/14/2014] [Accepted: 05/14/2014] [Indexed: 11/28/2022]
Abstract
Pericytes are located on the abluminal side of endothelial cells lining the microvasculature in all organs. They have been identified as multipotent progenitor cells in several tissues of the body including the human brain. New evidence suggests that pericytes contribute to tissue repair, but their role in the injured brain is largely unknown. Here, we investigate the role of pericytes in ischemic stroke. Using a pericyte-reporter mouse model, we provide unique evidence that regulator of G-protein signaling 5 expressing cells are activated pericytes that leave the blood vessel wall, proliferate and give rise to microglial cells after ischemic brain injury. Consistently, we show that activated pericytes express microglial markers in human stroke brain tissue. We demonstrate that human brain-derived pericytes adopt a microglial phenotype and upregulate mRNA specific for activated microglial cells under hypoxic conditions in vitro. Our study indicates that the vasculature is a novel source of inflammatory cells with a microglial phenotype in brain ischemia and hence identifies pericytes as an important new target for the development of future stroke therapies.
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Affiliation(s)
- Ilknur Özen
- Translational Neurology Group, Department of Clinical Science, Wallenberg Neuroscience Center, Lund University, 22184 Lund, Sweden
| | - Tomas Deierborg
- Experimental Neuroinflammation Laboratory, Department of Experimental Medical Science, BMC, Lund University, 22184 Lund, Sweden
| | - Kenichi Miharada
- Department of Molecular Medicine and Gene Therapy, Lund Strategic Center for Stem Cell Biology and Cell Therapy, BMC, Lund University, 22184 Lund, Sweden
| | - Thomas Padel
- Translational Neurology Group, Department of Clinical Science, Wallenberg Neuroscience Center, Lund University, 22184 Lund, Sweden
| | - Elisabet Englund
- Department of Neuropathology, Scania University Hospital, 22185 Lund, Sweden
| | - Guillem Genové
- Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, 17177 Stockholm, Sweden
| | - Gesine Paul
- Translational Neurology Group, Department of Clinical Science, Wallenberg Neuroscience Center, Lund University, 22184 Lund, Sweden
- Department of Neurology, Scania University Hospital, 22185 Lund, Sweden
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54
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Kozai TDY, Li X, Bodily LM, Caparosa EM, Zenonos GA, Carlisle DL, Friedlander RM, Cui XT. Effects of caspase-1 knockout on chronic neural recording quality and longevity: insight into cellular and molecular mechanisms of the reactive tissue response. Biomaterials 2014; 35:9620-34. [PMID: 25176060 DOI: 10.1016/j.biomaterials.2014.08.006] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Accepted: 08/01/2014] [Indexed: 12/17/2022]
Abstract
Chronic implantation of microelectrodes into the cortex has been shown to lead to inflammatory gliosis and neuronal loss in the microenvironment immediately surrounding the probe, a hypothesized cause of neural recording failure. Caspase-1 (aka Interleukin 1β converting enzyme) is known to play a key role in both inflammation and programmed cell death, particularly in stroke and neurodegenerative diseases. Caspase-1 knockout (KO) mice are resistant to apoptosis and these mice have preserved neurologic function by reducing ischemia-induced brain injury in stroke models. Local ischemic injury can occur following neural probe insertion and thus in this study we investigated the hypothesis that caspase-1 KO mice would have less ischemic injury surrounding the neural probe. In this study, caspase-1 KO mice were implanted with chronic single shank 3 mm Michigan probes into V1m cortex. Electrophysiology recording showed significantly improved single-unit recording performance (yield and signal to noise ratio) of caspase-1 KO mice compared to wild type C57B6 (WT) mice over the course of up to 6 months for the majority of the depth. The higher yield is supported by the improved neuronal survival in the caspase-1 KO mice. Impedance fluctuates over time but appears to be steadier in the caspase-1 KO especially at longer time points, suggesting milder glia scarring. These findings show that caspase-1 is a promising target for pharmacologic interventions.
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Affiliation(s)
- Takashi D Y Kozai
- Bioengineering, University of Pittsburgh, USA; Center for Neural Basis of Cognition, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, USA.
| | - Xia Li
- Bioengineering, University of Pittsburgh, USA
| | - Lance M Bodily
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, USA
| | - Ellen M Caparosa
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, USA
| | - Georgios A Zenonos
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, USA
| | - Diane L Carlisle
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, USA
| | - Robert M Friedlander
- Neuroapoptosis Laboratory, Department of Neurological Surgery, University of Pittsburgh, USA
| | - X Tracy Cui
- Bioengineering, University of Pittsburgh, USA; Center for Neural Basis of Cognition, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, USA.
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55
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Abstract
An important hallmark of many adult stem cell niches is their proximity to the vasculature in vivo, a feature common to neural stem cells (NSCs), mesenchymal stem cells (MSCs) from bone marrow, adipose, and other tissues, hematopoietic stem cells (HSCs), and many tumor stem cells. This review summarizes key studies supporting the vasculature's instructive role in adult stem cell niches, and the putative underlying molecular mechanisms by which blood vessels in these niches exert control over progenitor cell fates. The importance of the perivascular niche for pathology, notably tumor metastasis and dormancy, is also highlighted. Finally, the implications of the perivascular regulation of stem and progenitor cells on biomaterial design and the impact on future research directions are discussed.
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Affiliation(s)
- Andrew J Putnam
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109
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56
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Deguchi K, Liu N, Liu W, Omote Y, Kono S, Yunoki T, Deguchi S, Yamashita T, Ikeda Y, Abe K. Pericyte protection by edaravone after tissue plasminogen activator treatment in rat cerebral ischemia. J Neurosci Res 2014; 92:1509-19. [PMID: 24938625 PMCID: PMC4263311 DOI: 10.1002/jnr.23420] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Revised: 04/16/2014] [Accepted: 04/27/2014] [Indexed: 12/31/2022]
Abstract
Pericytes play a pivotal role in contraction, mediating inflammation and regulation of blood flow in the brain. In this study, changes of pericytes in the neurovascular unit (NVU) were examined in relation to the effects of exogenous tissue plasminogen activator (tPA) and a free radical scavenger, edaravone. Immunohistochemistry and Western blot analyses showed that the overlap between platelet-derived growth factor receptor β-positive pericytes and N-acetylglucosamine oligomers (NAGO)-positive endothelial cells increased significantly at 4 days after 90 min of transient middle cerebral artery occlusion (tMCAO). The number of pericytes and the overlap with NAGO decreased with tPA but recovered with edaravone 4 days after tMCAO with proliferation. Thus, tPA treatment damaged pericytes, resulting in the detachment from astrocytes and a decrease in glial cell line-derived neurotrophic factor secretion. However, treatment with edaravone greatly improved tPA-induced damage to pericytes. The present study demonstrates that exogenous tPA strongly damages pericytes and destroys the integrity of the NVU, but edaravone treatment can greatly ameliorate such damage after acute cerebral ischemia in rats.
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Affiliation(s)
- Kentaro Deguchi
- Department of Neurology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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57
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Nuschke A. Activity of mesenchymal stem cells in therapies for chronic skin wound healing. Organogenesis 2013; 10:29-37. [PMID: 24322872 DOI: 10.4161/org.27405] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Chronic or non-healing skin wounds present an ongoing challenge in advanced wound care, particularly as the number of patients increases while technology aimed at stimulating wound healing in these cases remains inefficient. Mesenchymal stem cells (MSCs) have proved to be an attractive cell type for various cell therapies due to their ability to differentiate into various cell lineages, multiple donor tissue types, and relative resilience in ex-vivo expansion, as well as immunomodulatory effects during transplants. More recently, these cells have been targeted for use in strategies to improve chronic wound healing in patients with diabetic ulcers or other stasis wounds. Here, we outline several mechanisms by which MSCs can improve healing outcomes in these cases, including reducing tissue inflammation, inducing angiogenesis in the wound bed, and reducing scarring following the repair process. Approaches to extend MSC life span in implant sites are also examined.
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Affiliation(s)
- Austin Nuschke
- Department of Pathology; University of Pittsburgh; Pittsburgh, PA USA
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58
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Tasso R, Ulivi V, Reverberi D, Lo Sicco C, Descalzi F, Cancedda R. In vivo implanted bone marrow-derived mesenchymal stem cells trigger a cascade of cellular events leading to the formation of an ectopic bone regenerative niche. Stem Cells Dev 2013; 22:3178-91. [PMID: 23924051 DOI: 10.1089/scd.2013.0313] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We recently reported that mouse bone marrow stromal cells, also known as bone marrow (BM)-derived mesenchymal stem cells (MSCs), seeded onto a scaffold and implanted in vivo, led to an ectopic bone deposition by host cells. This MSCs capacity was critically dependent on their commitment level, being present only in MSCs cultured in presence of fibroblast growth factor-2. Taking advantage of a chimeric mouse model, in this study we show that seeded MSCs trigger a cascade of events resulting in the mobilization of macrophages, the induction of their functional switch from a proinflammatory to a proresolving phenotype, and the subsequent formation of a bone regenerative niche through the recruitment, within the first 2 weeks of implantation, of endothelial progenitors and of cells with an osteogenic potential (CD146+CD105+), both of them derived from the BM. Moreover, we demonstrated that, in an inflammatory environment, MSCs secrete a large amount of prostaglandin E2 playing a key role in the macrophage phenotype switch.
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Affiliation(s)
- Roberta Tasso
- 1 Department of Experimental Medicine (DIMES), University of Genova , Genova, Italy
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59
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Blocki A, Wang Y, Koch M, Peh P, Beyer S, Law P, Hui J, Raghunath M. Not all MSCs can act as pericytes: functional in vitro assays to distinguish pericytes from other mesenchymal stem cells in angiogenesis. Stem Cells Dev 2013; 22:2347-55. [PMID: 23600480 DOI: 10.1089/scd.2012.0415] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Pericytes play a crucial role in angiogenesis and vascular maintenance. They can be readily identified in vivo and isolated as CD146(+)CD34(-) cells from various tissues. Whether these and other markers reliably identify pericytes in vitro is unclear. CD146(+)CD34(-) selected cells exhibit multilineage potential. Thus, their perivascular location might represent a stem cell niche. This has spurred assumptions that not only all pericytes are mesenchymal stromal cells (MSCs), but also that all MSCs can act as pericytes. Considering this hypothesis, we developed functional assays by confronting test cells with endothelial cultures based on matrigel assay, spheroid sprouting, and cord formation. We calibrated these assays first with commercial cell lines [CD146(+)CD34(-) placenta-derived pericytes (Pl-Prc), bone marrow (bm)MSCs and fibroblasts]. We then functionally compared the angiogenic abilities of CD146(+)CD34(-)selected bmMSCs with CD146(-) selected bmMSCs from fresh human bm aspirates. We show here that only CD146(+)CD34(-) selected Pl-Prc and CD146(+)CD34(-) selected bmMSCs maintain endothelial tubular networks on matrigel and improve endothelial sprout morphology. CD146(-) selected bmMSCs neither showed these abilities, nor did they attain pericyte function despite progressive CD146 expression once passaged. Thus, cell culture conditions appear to influence expression of this and other reported pericyte markers significantly without correlation to function. The newly developed assays, therefore, promise to close a gap in the in vitro identification of pericytes via function. Indeed, our functional data suggest that pericytes represent a subpopulation of MSCs in bm with a specialized role in vascular biology. However, these functions are not inherent to all MSCs.
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Affiliation(s)
- Anna Blocki
- NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore , Singapore, Singapore
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60
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Connection of pericyte-angiopoietin-Tie-2 system in diabetic retinopathy: friend or foe? Future Med Chem 2013. [PMID: 23190105 DOI: 10.4155/fmc.12.170] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Pericytes are distinctive regulators of vascular morphologenesis and function during vascular development and homeostasis. Pericytes have recently come into focus as implications of aberrant interactions between pericytes and endothelial cells in number of pathological angiogenesis conditions, including diabetic retinopathy and tumor angiogenesis. Pericyte dropout is a hallmark of early diabetic retinopathy. Abnormal angiopoietin (Ang)-Tie-2 signaling is one principal system participating in pericyte/endothelial cell dissociation during early stages of diabetic retinopathy. Angiopoietin 2 (Ang-2) is among the relevant growth factors induced by hypoxia and plays an important role in the initiation of retinal neovascularization and cause pericyte loss. Furthermore, high levels of VEGF synergize Ang-Tie-2 signaling during the development of diabetic retinopathy. An accelerated rate of clinical development Ang-Tie-2-manipulating drugs requests a better mechanistic understanding the connection between pericytes and Ang-Tie-2 systems both under normal and disease conditions. We summarize recent advances in pericyte study in conjunction with Ang-Tie-2 signaling and also discuss possible therapeutic strategies for diabetic retinopathy by targeting pericytes through manipulating Ang-Tie-2 signaling.
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61
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Abstract
Despite its limited regenerative capacity, the central nervous system (CNS) shares more repair mechanisms with peripheral tissues than previously recognized. Scar formation is a ubiquitous healing mechanism aimed at patching tissue defects via the generation of fibrous extracellular matrix (ECM). This process, orchestrated by stromal cells, can unfavorably affect the capacity of tissues to restore function. Vascular mural cells have been found to contribute to scarring after spinal cord injury. In the case of stroke, little is known about the responses of pericytes (PCs) and stromal cells. Here, we show that capillary PCs are rapidly lost after cerebral ischemia in both experimental and human stroke. Coincident with this loss is a massive proliferation of resident platelet-derived growth factor receptor beta (PDGFRβ)(+) and CD105(+) stromal cells, which originate from the neurovascular unit and deposit ECM in the ischemic mouse brain. The presence of PDGFRβ(+) stromal cells demarcates a fibrotic, contracted, and macrophage-laden lesion core from the rim of hypertrophic astroglia in both experimental and human stroke. We suggest that a previously unrecognized population of CNS-resident stromal cells drives a dynamic process of scarring after cerebral ischemia, which appears distinct from the glial scar and represents a novel target for regenerative stroke therapies.
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62
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Brain pericyte plasticity as a potential drug target in CNS repair. Drug Discov Today 2012; 18:456-63. [PMID: 23266366 DOI: 10.1016/j.drudis.2012.12.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 11/23/2012] [Accepted: 12/11/2012] [Indexed: 01/09/2023]
Abstract
Brain pericytes (BrPCs) are essential cellular components of the central nervous system neurovascular unit involved in the regulation of blood flow, blood-brain barrier function, as well as in the stabilization of the vessel architecture. More recently, it became evident that BrPCs, besides their regulatory activities in brain vessel function and homeostasis, have pleiotropic functions in the adult CNS ranging from stromal and regeneration promoting activities to stem cell properties. This special characteristic confers BrPC cell plasticity, being able to display features of other cells within the organism. BrPCs might also be causally involved in certain brain diseases. Due to these properties BrPCs might be potential drug targets for future therapies of neurological disorders. This review summarizes BrPC properties, disorders in which this cell type might be involved, and provides suggestions for future therapeutic developments targeting BrPCs.
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63
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Rusu MC, Didilescu AC, Stănescu R, Pop F, Mănoiu VM, Jianu AM, Vâlcu M. The mandibular ridge oral mucosa model of stromal influences on the endothelial tip cells: an immunohistochemical and TEM study. Anat Rec (Hoboken) 2012. [PMID: 23192856 DOI: 10.1002/ar.22630] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This study aimed to evaluate by immunohistochemistry and transmission electron microscopy (TEM) the morphological features of the oral mucosa endothelial tip cells (ETCs) and to determine the immune and ultrastructural patterns of the stromal nonimmune cells which could influence healing processes. Immune labeling was performed on bioptic samples obtained from six edentulous patients undergoing surgery for dental implants placement; three normal samples were collected from patients prior to the extraction of the third mandibular molar. The antibodies were tested for CD34, CD117(c-kit), platelet derived growth factor receptor-alpha (PDGFR-α), Mast Cell Tryptase, CD44, vimentin, CD45, CD105, alpha-smooth muscle actin, FGF2, Ki67. In light microscopy, while stromal cells (StrCs) of the reparatory and normal oral mucosa, with a fibroblastic appearance, were found positive for a CD34/CD44/CD45/CD105/PDGFR-α/vimentin immune phenotype, the CD117/c-kit labeling led to a positive stromal reaction only in the reparatory mucosa. In TEM, non-immune StrCs presenting particular ultrastructural features were identified as circulating fibrocytes (CFCs). Within the lamina propria CFCs were in close contact with ETCs. Long processes of the ETCs were moniliform, and hook-like collaterals were arising from the dilated segments, suggestive for a different stage migration. Maintenance and healing of oral mucosa are so supported by extensive processes of angiogenesis, guided by ETCs that, in turn, are influenced by the CFCs that populate the stromal compartment both in normal and reparatory states. Therefore, CFCs could be targeted by specific therapies, with pro- or anti-angiogenic purposes.
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Affiliation(s)
- Mugurel Constantin Rusu
- Division of Anatomy, Faculty of Dental Medicine, Carol Davila University of Medicine and Pharmacy, Bucharest, Romania.
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64
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Sharma V, Ling TW, Rewell SS, Hare DL, Howells DW, Kourakis A, Wookey PJ. A novel population of α-smooth muscle actin-positive cells activated in a rat model of stroke: an analysis of the spatio-temporal distribution in response to ischemia. J Cereb Blood Flow Metab 2012; 32:2055-65. [PMID: 22805872 PMCID: PMC3493995 DOI: 10.1038/jcbfm.2012.107] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In a rat model of stroke, the spatio-temporal distribution of α-smooth muscle actin-positive, (αSMA+) cells was investigated in the infarcted hemisphere (ipsilateral) and compared with the contralateral hemisphere. At day 3 postischemia, αSMA+ cells were concentrated in two main loci within the ipsilateral hemisphere (Area A) in the medial corpus callosum and (Area B) midway through the striatum adjacent to the lateral ventricle. By day 7 and further by day 14, fewer αSMA+ cells remained in Areas A and B but a steady increase in the peri-infarct was observed. αSMA+ cells also expressed glial acidic fibrillary protein [GFAP: αSMA+/GFAP+ (29%); αSMA+/GFAP- (71%) phenotypes] and feline leukemia virus C receptor 2 (FLVCR2), but not ED1(microglia) and established markers of pericytes normally located in vascular wall. αSMA+ cells were also located close to the subventricular zones (SVZ) adjacent to Areas A and B. In conclusion, αSMA+ cells have been identified in a spatial and temporal sequence from the SVZ, at intermediate loci and in the vicinity of the peri-infarct. It is hypothesized that novel populations of αSMA+ precursors of pericytes are born on the SVZ, migrate into the peri-infarct region and are incorporated into new vessels of the peri-infarct regions.
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Affiliation(s)
- Varun Sharma
- Cardiology Department, Austin Health, Melbourne, Victoria, Australia
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65
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Nakamura K, Kamouchi M, Arimura K, Nishimura A, Kuroda J, Ishitsuka K, Tokami H, Sugimori H, Ago T, Kitazono T. Extracellular acidification activates cAMP responsive element binding protein via Na+/H+ exchanger isoform 1-mediated Ca²⁺ oscillation in central nervous system pericytes. Arterioscler Thromb Vasc Biol 2012; 32:2670-7. [PMID: 22922957 DOI: 10.1161/atvbaha.112.254946] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
OBJECTIVE We have previously shown that Na(+)/H(+) exchanger isoform 1 (NHE1) plays an important role in Ca(2+) signaling and cell proliferation in human central nervous system (CNS) pericytes. The aims of the present study were to elucidate how NHE1-induced Ca(2+) signaling during acidosis is transformed into cellular responses in CNS pericytes. METHODS AND RESULTS Human CNS pericytes were cultured, and the activation of cAMP responsive element-binding protein (CREB) was evaluated by Western blotting analysis, immunofluorescence, and luciferase assays. In human CNS pericytes, low extracellular Na(+) or low pH generated Ca(2+) oscillation and subsequently phosphorylated Ca(2+)/calmodulin-dependent kinase II (CaMKII) and CREB in a time-dependent manner. Focal cerebral ischemia was applied using photothrombotic distal middle cerebral artery occlusion in mice, and the phosphorylation of CREB and the production of interleukin-6 were observed in pericytes migrating into the peri-infarct penumbra during the early phase after ischemic insult. CONCLUSIONS Our results indicate that extracellular acidosis induces Ca(2+) oscillation via NHE1, leading to Ca(2+)/CaMKII-dependent CREB activation in human CNS pericytes. Acidosis may upregulate a variety of proteins, such as interleukin-6, through the NHE1-Ca2+/CaMKII-CREB pathway in brain pericytes and may thus modulate brain ischemic insult.
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Affiliation(s)
- Kuniyuki Nakamura
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
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66
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Liman TG, Endres M. New vessels after stroke: postischemic neovascularization and regeneration. Cerebrovasc Dis 2012; 33:492-9. [PMID: 22517438 DOI: 10.1159/000337155] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 02/08/2012] [Indexed: 12/30/2022] Open
Abstract
The formation of new blood vessels after acute ischemic stroke is one of the most promising approaches to future therapies in the emerging field of stroke medicine. Angiogenesis and postnatal vasculogenesis are the underlying mechanisms of the formation of new blood vessels. Bone marrow-derived endothelial progenitor cells (EPCs) are thought to play an important role in neovascularization and during the regenerative processes after a vascular injury as well as in the maintenance of endothelial integrity. This review summarizes possible mechanisms of angiogenesis, postischemic neovascularization and regeneration with a focus on the potential role of EPCs as a risk marker and as a therapeutic target in stroke medicine.
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Affiliation(s)
- T G Liman
- Center for Stroke Research Berlin, Charité-Universitätsmedizin Berlin, Berlin, Germany.
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67
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Liu CH, Ren JQ, You Z, Yang J, Liu CM, Uppal R, Liu PK. Noninvasive detection of neural progenitor cells in living brains by MRI. FASEB J 2011; 26:1652-62. [PMID: 22198388 DOI: 10.1096/fj.11-199547] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The presence of pericytes in brain regions undergoing repair is evident of the recruitment of bone marrow-derived multipotent regenerative cells to the neurovascular unit during angiogenesis. At present, post mortem sampling is the only way to identify them. Therefore, such cell typing is inadequate for preserving neural progenitor cells for any meaningful stem cell therapy. We aimed to target cerebral pericytes in vivo using dual gene transcript-targeted MRI (GT-tMRI) in male C57black6 mice after a 60-min bilateral carotid artery occlusion (BCAO). We attached superparamagnetic iron oxide nanoparticles (SPIONs) to phosphorothioate-modified micro-DNA that targets actin or nestin mRNA. Because BCAO compromises the blood-brain barrier (BBB) and induces expression of α-smooth muscle (αSM)-actin and nestin antigens by pericytes in new vessels, we delivered pericyte-specific magnetic resonance contrast agents (SPION-actin or SPION-nestin at 4 mg Fe/kg) by i.p. injection to C57black6 mice that had experienced BCAO. We demonstrated that the surge in cerebral iron content by inductively coupled plasma-mass spectrometry matched the increase in the frequency of relaxivity. We also found that SPION-nestin was colocalized in αSM- actin- and nestin-expressing pericytes in BCAO-treated C57black6 or transgenic mice [B6.Cg-Tg(CAG-mRFP1) 1F1Hadj/J, expressing red fluorescent protein by actin promoter]. We identified pericytes in the repair patch in living brains after BCAO with a voxel size of 0.03 mm(3). The presence of electron-dense nanoparticles in vascular pericytes in the region of BBB injury led us to draw the conclusion that GT-tMRI can noninvasively reveal neural progenitor cells during vascularization.
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Affiliation(s)
- Christina H Liu
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA 02129, USA
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68
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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: 712] [Impact Index Per Article: 54.8] [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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69
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Yang Y, Jalal FY, Thompson JF, Walker EJ, Candelario-Jalil E, Li L, Reichard RR, Ben C, Sang QX, Cunningham LA, Rosenberg GA. Tissue inhibitor of metalloproteinases-3 mediates the death of immature oligodendrocytes via TNF-α/TACE in focal cerebral ischemia in mice. J Neuroinflammation 2011; 8:108. [PMID: 21871134 PMCID: PMC3180275 DOI: 10.1186/1742-2094-8-108] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 08/29/2011] [Indexed: 11/10/2022] Open
Abstract
Background and Purpose Oligodendrocyte (OL) death is important in focal cerebral ischemia. TIMP-3 promotes apoptosis in ischemic neurons by inhibiting proteolysis of TNF-α superfamily of death receptors. Since OLs undergo apoptosis during ischemia, we hypothesized that TIMP-3 contributes to OL death. Methods Middle cerebral artery occlusion (MCAO) was induced in Timp-3 knockout (KO) and wild type (WT) mice with 24 or 72 h of reperfusion. Cell death in white matter was investigated by stereology and TUNEL. Mature or immature OLs were identified using antibodies against glutathione S-transferase-π (GST-π) and galactocerebroside (GalC), respectively. Expression and level of proteins were examined using immunohistochemistry and immunoblotting. Protein activities were determined using a FRET peptide. Results Loss of OL-like cells was detected at 72 h only in WT ischemic white matter where TUNEL showed greater cell death. TIMP-3 expression was increased in WT reactive astrocytes. GST-π was reduced in ischemic white matter of WT mice compared with WT shams with no difference between KO and WT at 72 h. GalC level was significantly increased in both KO and WT ischemic white matter at 72 h. However, the increase in GalC in KO mice was significantly higher than WT; most TUNEL-positive cells in ischemic white matter expressed GalC, suggesting TIMP-3 deficiency protects the immature OLs from apoptosis. There were significantly higher levels of cleaved caspase-3 at 72 h in WT white matter than in KO. Greater expression of MMP-3 and -9 was seen in reactive astrocytes and/or microglia/macrophages in WT at 72 h. We found more microglia/macrophages in WT than in KO, which were the predominant source of increased TNF-α detected in the ischemic white matter. TACE activity was significantly increased in ischemic WT white matter, which was expressed in active microglia/macrophages and OLs. Conclusions Our results suggested that focal ischemia leads to proliferation of immature OLs in white matter and that TIMP-3 contributes to a caspase-3-dependent immature OL death via TNF-α-mediated neuroinflammation. Future studies will be needed to delineate the role of MMP-3 and MMP-9 that were increased in the Timp-3 wild type.
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Affiliation(s)
- Yi Yang
- Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
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70
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Kamouchi M, Ago T, Kuroda J, Kitazono T. The possible roles of brain pericytes in brain ischemia and stroke. Cell Mol Neurobiol 2011; 32:159-65. [PMID: 21830084 DOI: 10.1007/s10571-011-9747-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Accepted: 07/28/2011] [Indexed: 02/06/2023]
Abstract
Brain pericytes regulate a variety of functions, such as microcirculation, angiogenesis, and the blood brain barrier in the brain. Recent studies have also shown that they are pluripotent in a manner similar to mesenchymal stem cells. Since, brain pericytes actively control these functions, these cells probably play an important role not only during brain ischemia, but also in the post-stroke period.
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Affiliation(s)
- Masahiro Kamouchi
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan.
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71
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Kamouchi M, Ago T, Kitazono T. Brain pericytes: emerging concepts and functional roles in brain homeostasis. Cell Mol Neurobiol 2011; 31:175-93. [PMID: 21061157 DOI: 10.1007/s10571-010-9605-x] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 09/22/2010] [Indexed: 11/30/2022]
Abstract
Brain pericytes are an important constituent of neurovascular unit. They encircle endothelial cells and contribute to the maturation and stabilization of the capillaries in the brain. Recent studies have revealed that brain pericytes play pivotal roles in a variety of brain functions, such as regulation of capillary flow, angiogenesis, blood brain barrier, immune responses, and hemostasis. In addition, brain pericytes are pluripotent and can differentiate into different lineages similar to mesenchymal stem cells. The brain pericytes are revisited as a key player to maintain brain function and repair brain damage.
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Affiliation(s)
- Masahiro Kamouchi
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
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72
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Bonkowski D, Katyshev V, Balabanov RD, Borisov A, Dore-Duffy P. The CNS microvascular pericyte: pericyte-astrocyte crosstalk in the regulation of tissue survival. Fluids Barriers CNS 2011; 8:8. [PMID: 21349156 PMCID: PMC3042982 DOI: 10.1186/2045-8118-8-8] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 01/18/2011] [Indexed: 01/24/2023] Open
Abstract
The French scientist Charles Benjamin Rouget identified the pericyte nearly 140 years ago. Since that time the role of the pericyte in vascular function has been difficult to elucidate. It was not until the development of techniques to isolate and culture pericytes that scientists have begun to understand the true impact of this unique cell in the maintenance of tissue homeostasis. In the brain the pericyte is an integral cellular component of the blood-brain barrier and, together with other cells of the neurovascular unit (endothelial cells, astrocytes and neurons) the pericyte makes fine-tuned regulatory adjustments and adaptations to promote tissue survival. These regulatory changes involve trans-cellular communication networks between cells. In this review we consider evidence for cell-to-cell crosstalk between pericytes and astrocytes during development and in adult brain.
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Affiliation(s)
- Drew Bonkowski
- Department of Neurology, Wayne State University School of Medicine, 421 East Canfield Road, Detroit, Michigan 48201, USA.
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73
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Hao Q, Su H, Palmer D, Sun B, Gao P, Yang GY, Young WL. Bone marrow-derived cells contribute to vascular endothelial growth factor-induced angiogenesis in the adult mouse brain by supplying matrix metalloproteinase-9. Stroke 2010; 42:453-8. [PMID: 21164138 DOI: 10.1161/strokeaha.110.596452] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND PURPOSE Our previous studies have shown that bone marrow-derived cells (BMDCs) home to a brain angiogenic focus. The angiogenic response to vascular endothelial growth factor (VEGF) stimulation is reduced in matrix metalloproteinase-9 (MMP-9) knockout mice. We hypothesized that BMDCs contribute to VEGF-induced angiogenesis by supplying MMP-9. METHODS Bone marrow (BM) transplantation was conducted using MMP-9 knockout (MMP-9 KO) or wild-type (WT) mice as both donors and recipients. Adeno-associated viral vectors expressing VEGF or LacZ were injected into the striatum 4 weeks after BM transplantation. Circulating white blood cells (WBCs), microvessel density, number of BMDCs, and MMP-9 activity around the injection site were analyzed. RESULTS Two weeks after vector injection, circulating WBCs increased in WT mice but not in MMP-9 KO mice. VEGF overexpression increased microvessel density by 38% in WT mice 4 weeks after vector injection (P=0.0001). After transplantation of MMP-9 KO BM to WT mice, microvessel density only increased 18% after VEGF stimulation (P=0.037), with MMP-9 activity reduced to 35% of the level of WT mice (P<0.01). There was minimal angiogenic response in MMP-9 KO mice with MMP-9 KO BM (P=0.28). Transplantation of WT BM to MMP-9 KO mice restored brain angiogenic response to 92% of the WT level, ie, a 30% increase of microvessel density with VEGF overexpression (P=0.0006); MMP-9 activity was similar to that in WT mice. CONCLUSIONS BM-derived MMP-9 plays an important role in BM cell mobilization and focal angiogenesis in the brain in response to VEGF stimulation.
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Affiliation(s)
- Qi Hao
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA 94110, USA
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74
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Li L, Harms KM, Ventura PB, Lagace DC, Eisch AJ, Cunningham LA. Focal cerebral ischemia induces a multilineage cytogenic response from adult subventricular zone that is predominantly gliogenic. Glia 2010; 58:1610-9. [PMID: 20578055 DOI: 10.1002/glia.21033] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this study was to ascertain the relative contribution of neural stem/progenitor cells (NSPCs) of the subventricular zone (SVZ) to lineages that repopulate the injured striatum following focal ischemia. We utilized a tamoxifen-inducible Cre/loxP system under control of the nestin promoter, which provides permanent YFP labeling of multipotent nestin(+) SVZ-NSPCs prior to ischemic injury and continued YFP expression in all subsequent progeny following stroke. YFP reporter expression was induced in adult male nestin-CreER(T2):R26R-YFP mice by tamoxifen administration (180 mg kg(-1), daily for 5 days). Fourteen days later, mice were subjected to 60-min transient middle cerebral artery occlusion (MCAO) and sacrificed at 2 days, 2 weeks, or 6 weeks post-MCAO for phenotypic fate mapping of YFP(+) cells using lineage-specific markers. Migration of YFP(+) cells from SVZ into the injured striatal parenchyma was apparent at 2 and 6 weeks, but not 2 days, post-MCAO. At 2 weeks post-MCAO, the average percent distribution of YFP(+) cells within the injured striatal parenchyma was as follows: 10% Dcx(+) neuroblasts, 15-20% oligodendrocyte progenitors, 59% GFAP(+) astrocytes, and only rare NeuN(+) postmitotic neurons. A similar phenotypic distribution was observed at 6 weeks, except for an increased average percentage of YFP(+) cells that expressed Dcx(+) (20%) or NeuN (5%). YFP(+) cells did not express endothelial markers, but displayed unique anatomical relationships with striatal vasculature. These results indicate that nestin(+) NSPCs within the SVZ mount a multilineage response to stroke that includes a gliogenic component more predominant than previously appreciated.
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Affiliation(s)
- Lu Li
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM 87131-0001, USA
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75
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Jung KH, Chu K, Lee ST, Bahn JJ, Jeon D, Kim JH, Kim S, Won CH, Kim M, Lee SK, Roh JK. Multipotent PDGFRβ-expressing cells in the circulation of stroke patients. Neurobiol Dis 2010; 41:489-97. [PMID: 21074616 DOI: 10.1016/j.nbd.2010.10.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Revised: 09/18/2010] [Accepted: 10/27/2010] [Indexed: 12/30/2022] Open
Abstract
Tissue pericytes respond to injury, and support vascular and tissue regeneration. The presence of pericytes in the circulation may provide an attractive framework for tissue regeneration. Here, we detected multipotent pericyte-like cells in the circulating blood and determined its profiles during cerebral ischemia. Pericyte-like cells were isolated from the peripheral blood of acute stroke patients or asymptomatic individuals with vascular risk factors by fluorescence or magnetic activated cell sorting with anti-PDGF receptor-beta (PDGFRβ) antibody. The morphologic and molecular features of circulating PDGFRβ(+) cells were compared with tissue pericytes, and the associations with respect to quantity in the blood, culture outcome, and patient characteristics were analyzed. We found an increase in circulating PDGFRβ(+) cells in acute stroke patients compared to controls and a correlation with neurologic impairment. The isolated PDGFRβ(+) cells expressed mesenchymal stem cell markers, proliferated, and were multipotent under permissive culture conditions. The multipotent nature of these cells was comparable to fat-derived PDGFRβ(+) cells. These cells could be obtained by pharmacologic stimulation using bone marrow mobilizer. Circulating PDGFRβ(+) cells will be useful for future research involving endogenous recovery or autologous cell-based therapy.
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Affiliation(s)
- Keun-Hwa Jung
- Department of Neurology, Stroke & Stem Cell Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul, South Korea
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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: 1097] [Impact Index Per Article: 78.4] [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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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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Denes A, Thornton P, Rothwell NJ, Allan SM. Inflammation and brain injury: acute cerebral ischaemia, peripheral and central inflammation. Brain Behav Immun 2010; 24:708-23. [PMID: 19770034 DOI: 10.1016/j.bbi.2009.09.010] [Citation(s) in RCA: 218] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 09/15/2009] [Accepted: 09/15/2009] [Indexed: 12/18/2022] Open
Abstract
Inflammation is a classical host defence response to infection and injury that has many beneficial effects. However, inappropriate (in time, place and magnitude) inflammation is increasingly implicated in diverse disease states, now including cancer, diabetes, obesity, atherosclerosis, heart disease and, most relevant here, CNS disease. A growing literature shows strong correlations between inflammatory status and the risk of cerebral ischaemia (CI, most commonly stroke), as well as with outcome from an ischaemic event. Intervention studies to demonstrate a causal link between inflammation and CI (or its consequences) are limited but are beginning to emerge, while experimental studies of CI have provided direct evidence that key inflammatory mediators (cytokines, chemokines and inflammatory cells) contribute directly to ischaemic brain injury. However, it remains to be determined what the relative importance of systemic (largely peripheral) versus CNS inflammation is in CI. Animal models in which CI is driven by a CNS intervention may not accurately reflect the clinical condition; stroke being typically induced by atherosclerosis or cardiac dysfunction, and hence current experimental paradigms may underestimate the contribution of peripheral inflammation. Experimental studies have already identified a number of potential anti-inflammatory therapeutic interventions that may limit ischaemic brain damage, some of which have been tested in early clinical trials with potentially promising results. However, a greater understanding of the contribution of inflammation to CI is still required, and this review highlights some of the key mechanism that may offer future therapeutic targets.
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Affiliation(s)
- A Denes
- Faculty of Life Sciences, The University of Manchester, Manchester, UK
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79
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Harms KM, Li L, Cunningham LA. Murine neural stem/progenitor cells protect neurons against ischemia by HIF-1alpha-regulated VEGF signaling. PLoS One 2010; 5:e9767. [PMID: 20339541 PMCID: PMC2842303 DOI: 10.1371/journal.pone.0009767] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 03/03/2010] [Indexed: 01/19/2023] Open
Abstract
Focal cerebral ischemia following middle cerebral artery occlusion (MCAO) stimulates a robust cytogenic response from the adult subventricular zone (SVZ) that includes massive proliferation of neural stem/progenitor cells (NSPCs) and cellular migration into the injury area. To begin to explore beneficial roles of NSPCs in this response, we investigated the ability of embryonic and postnatal NSPCs to promote neuronal survival under conditions of in vivo and in vitro ischemia. Intracerebral transplantation of NSPCs attenuated neuronal apoptosis in response to focal ischemia induced by transient MCAO, and prevented neuronal cell death of cortical neurons in response to oxygen-glucose deprivation (OGD) in culture. NSPC-mediated neuroprotection was blocked by the pharmacological inhibitors of vascular endothelial growth factor (VEGF), SU1498 and Flt-1Fc. Embryonic and postnatal NSPCs were both intrinsically resistant to brief OGD exposure, and constitutively expressed both hypoxia-inducible factor 1α (HIF-1α) transcription factor and its downstream target, VEGF. Genomic deletion of HIF-1α by Cre-mediated excision of exon 2 in NSPC cultures resulted in >50% reduction of VEGF production and ablation of NSPC-mediated neuroprotection. These findings indicate that NSPCs promote neuronal survival under ischemic conditions via HIF-1α-VEGF signaling pathways and support a role for NSPCs in promotion of neuronal survival following stroke.
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Affiliation(s)
- Kate M. Harms
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Lu Li
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Lee Anna Cunningham
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
- * E-mail:
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80
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Jin R, Yang G, Li G. Inflammatory mechanisms in ischemic stroke: role of inflammatory cells. J Leukoc Biol 2010; 87:779-89. [PMID: 20130219 DOI: 10.1189/jlb.1109766] [Citation(s) in RCA: 1168] [Impact Index Per Article: 83.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Inflammation plays an important role in the pathogenesis of ischemic stroke and other forms of ischemic brain injury. Experimentally and clinically, the brain responds to ischemic injury with an acute and prolonged inflammatory process, characterized by rapid activation of resident cells (mainly microglia), production of proinflammatory mediators, and infiltration of various types of inflammatory cells (including neutrophils, different subtypes of T cells, monocyte/macrophages, and other cells) into the ischemic brain tissue. These cellular events collaboratively contribute to ischemic brain injury. Despite intense investigation, there are still numerous controversies concerning the time course of the recruitment of inflammatory cells in the brain and their pathogenic roles in ischemic brain injury. In this review, we provide an overview of the time-dependent recruitment of different inflammatory cells following focal cerebral I/R. We discuss how these cells contribute to ischemic brain injury and highlight certain recent findings and currently unanswered questions about inflammatory cells in the pathophysiology of ischemic stroke.
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Affiliation(s)
- Rong Jin
- Department of Neurosurgery, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA
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Abstract
Rouget, in 1873, was the first to describe a population of cells surrounding capillaries, which he regarded as contractile elements. Fifty years later, Zimmermann termed these cells "pericytes" and distinguished three subtypes along the vascular tree. Since then, the discussion concerning the contractile ability of pericytes has never ceased. Current concepts of pericyte biology rather suggest critical roles in the maintenance of homeostasis, blood-brain barrier (BBB) integrity, angiogenesis, and neovascularization. In addition, data from models of brain pathology suggest that novel pericytes are recruited from the bone marrow, but their respective precursor remains enigmatic. Recent data also suggest an important role in the regulation of cerebral blood flow, thus confirming Rouget's original idea. However, comparison of data from different studies is often constrained by the fact that pericytes were questionably identified. Although a clear-cut definition exists, defining pericytes as part of the vascular wall being enclosed in its basement membrane, pericytes are often mixed up with adjacent cell types of the vascular wall, the perivascular space, and the juxtavascular parenchyma. In fact, their identification is difficult-if not impossible-in standard histological sections. An unambiguous distinction, however, is possible at the ultrastructural level and in semi-thin sections, where their location within the vascular basement membrane can be displayed. Using these techniques in combination with immunological staining methods allows demarking their unique morphology and location. Here, we review original papers describing pericytes, briefly outline their topography within the vascular compartments, describe methods for their identification, and summarize current concepts of their function.
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Affiliation(s)
- Martin Krueger
- Dr. Senckenbergische Anatomie, Institute of Clinical Neuroanatomy, J W Goethe-University, Frankfurt/Main, Germany
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82
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Larsson E, Fredlund Fuchs P, Heldin J, Barkefors I, Bondjers C, Genové G, Arrondel C, Gerwins P, Kurschat C, Schermer B, Benzing T, Harvey SJ, Kreuger J, Lindahl P. Discovery of microvascular miRNAs using public gene expression data: miR-145 is expressed in pericytes and is a regulator of Fli1. Genome Med 2009; 1:108. [PMID: 19917099 PMCID: PMC2808743 DOI: 10.1186/gm108] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 10/14/2009] [Accepted: 11/16/2009] [Indexed: 01/08/2023] Open
Abstract
Background A function for the microRNA (miRNA) pathway in vascular development and angiogenesis has been firmly established. miRNAs with selective expression in the vasculature are attractive as possible targets in miRNA-based therapies. However, little is known about the expression of miRNAs in microvessels in vivo. Here, we identified candidate microvascular-selective miRNAs by screening public miRNA expression datasets. Methods Bioinformatics predictions of microvascular-selective expression were validated with real-time quantitative reverse transcription PCR on purified microvascular fragments from mouse. Pericyte expression was shown with in situ hybridization on tissue sections. Target sites were identified with 3' UTR luciferase assays, and migration was tested in a microfluid chemotaxis chamber. Results miR-145, miR-126, miR-24, and miR-23a were selectively expressed in microvascular fragments isolated from a range of tissues. In situ hybridization and analysis of Pdgfb retention motif mutant mice demonstrated predominant expression of miR-145 in pericytes. We identified the Ets transcription factor Friend leukemia virus integration 1 (Fli1) as a miR-145 target, and showed that elevated levels of miR-145 reduced migration of microvascular cells in response to growth factor gradients in vitro. Conclusions miR-126, miR-24 and miR-23a are selectively expressed in microvascular endothelial cells in vivo, whereas miR-145 is expressed in pericytes. miR-145 targets the hematopoietic transcription factor Fli1 and blocks migration in response to growth factor gradients. Our findings have implications for vascular disease and provide necessary information for future drug design against miRNAs with selective expression in the microvasculature.
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Affiliation(s)
- Erik Larsson
- Wallenberg Laboratory for Cardiovascular Research, Bruna Stråket 16, Sahlgrenska University Hospital, SE-413 45 Gothenburg, Sweden
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83
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Turn-over of meningeal and perivascular macrophages in the brain of MCP-1-, CCR-2- or double knockout mice. Exp Neurol 2009; 219:583-5. [PMID: 19615366 DOI: 10.1016/j.expneurol.2009.07.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Revised: 06/30/2009] [Accepted: 07/06/2009] [Indexed: 11/23/2022]
Abstract
Perivascular and meningeal macrophages are important for immune surveillance in the healthy and the injured brain. Monocyte chemoattractant protein-1 (MCP-1) regulates macrophage migration and permeability of the blood brain barrier. In the present study, we investigated the influence of MCP-1 or/and chemokine receptor 2 (CCR2)-deficiency on macrophage turnover. The results showed no influence of single MCP-1- or CCR-2-deficiency, but double-deficient mice revealed a virtual absence of blood-borne macrophage recruitment. This finding emphasizes that the MCP-1/CCR2 axis is crucially important for macrophage turnover and compensatory mechanisms remain only partially sufficient to sustain regulatory functions.
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84
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Sorrell JM, Baber MA, Caplan AI. Influence of adult mesenchymal stem cells on in vitro vascular formation. Tissue Eng Part A 2009; 15:1751-61. [PMID: 19196139 PMCID: PMC2792097 DOI: 10.1089/ten.tea.2008.0254] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Accepted: 11/07/2008] [Indexed: 01/31/2023] Open
Abstract
The effective delivery of bioactive molecules to wound sites hasten repair. Cellular therapies provide a means for the targeted delivery of a complex, multiple arrays of bioactive factors to wound sites. Thus, the identification of ideal therapeutic populations is an essential aspect of this approach. In vitro assays can provide an important first step toward this goal by selecting populations that are likely suitable for more expensive and time-consuming in vivo assays. In this study, bone marrow-derived mesenchymal stem cells (BM-MSCs) were integrated into a three-dimensional coculture system that supports the development and stabilization of vascular tube-like structures. The presence of a limited number of BM-MSCs resulted in their coalignment with vascular structures, and it further resulted in increased tubule numbers and complexity. Thus, these studies suggest that BM-MSCs functionally interacted with and were attracted to in vitro formed vascular structures. Further, these cells also provided sufficient bioactive factors and matrix molecules to support the formation of tubular arrays and the stabilization of these arrays. This in vitro system provides a means for assessing the function of BM-MSCs in aspects of the angiogenic component of wound repair.
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Affiliation(s)
- J Michael Sorrell
- Department of Biology, Skeletal Research Center, Case Western Reserve University, Cleveland, OH 44106, USA.
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85
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The potential of neural stem cells to repair stroke-induced brain damage. Acta Neuropathol 2009; 117:469-80. [PMID: 19283395 DOI: 10.1007/s00401-009-0516-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2008] [Revised: 03/04/2009] [Accepted: 03/05/2009] [Indexed: 01/19/2023]
Abstract
Acute injuries to CNS such as stroke induce neural progenitor proliferation in adult brain which might be an endogenous attempt to self-repair. This process is known to be altered by several exogenous and endogenous modulators including growth factors that could help to reinforce the post-stroke neurogenesis. Increasing the neurogenesis may be a future therapeutic option to decrease the cognitive and behavioral deficits following stroke. In addition, transplantation of various types of stem cells into the injured brain is currently thought to be an exciting option to replace the neurons lost in the post-ischemic brain. These include immortalized stem cell lines, neural progenitors prepared from embryonic and adult animals and mesenchymal stem cells. Using exogenous stem cells in addition to modulating endogenous neurogenesis, we may be able to repair the injured brain after a devastating stroke. This article reviewed the current literature of these two issues.
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86
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Navaratna D, Guo S, Arai K, Lo EH. Mechanisms and targets for angiogenic therapy after stroke. Cell Adh Migr 2009; 3:216-23. [PMID: 19363301 DOI: 10.4161/cam.3.2.8396] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Stroke remains a major health problem worldwide, and is the leading cause of serious long-term disability. Recent findings now suggest that strategies to enhance angiogenesis after focal cerebral ischemia may provide unique opportunities to improve clinical outcomes during stroke recovery. In this mini-review, we survey emerging mechanisms and potential targets for angiogenic therapies in brain after stroke. Multiple elements may be involved, including growth factors, adhesion molecules and progenitor cells. Furthermore, cross talk between angiogenesis and neurogenesis may also provide additional substrates for plasticity and remodeling in the recovering brain. A better understanding of the molecular interplay between all these complex pathways may lead to novel therapeutic avenues for tackling this difficult disease.
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Affiliation(s)
- Deepti Navaratna
- Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, USA.
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87
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Shi X. Cochlear pericyte responses to acoustic trauma and the involvement of hypoxia-inducible factor-1alpha and vascular endothelial growth factor. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 174:1692-704. [PMID: 19349367 DOI: 10.2353/ajpath.2009.080739] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This study explored the effect of acoustic trauma on cochlear pericytes. Transmission electron microscopy revealed that pericytes on capillaries of the stria vascularis were closely associated with the endothelium in both control guinea pigs and mice. Pericyte foot processes were tightly positioned adjacent to endothelial cells. Exposure to wide-band noise at a level of 120 dB for 3 hours per day for 2 consecutive days produced a significant hearing threshold shift and structurally damaged blood vessels in the stria vascularis. Additionally, the serum protein, IgG, was observed to leak from capillaries of the stria vascularis, and pericytes lost their tight association with endothelial cells. Levels of the pericyte structural protein, desmin, substantially increased after noise exposure in both guinea pigs and mice with a corresponding increase in pericyte coverage of vessels. Increased expression levels of desmin were associated with the induction of hypoxia inducible factor (HIF)-1alpha and the up-regulation of vascular endothelial growth factor (VEGF). Inhibition of HIF-1alpha activity caused a decrease in VEGF expression levels in stria vascularis vessels. Blockade of VEGF activity with SU1498, a VEGF receptor inhibitor, significantly attenuated the expression of desmin in pericytes. These data demonstrate that cochlear pericytes are markedly affected by acoustic trauma and display an abnormal morphology. HIF-1alpha activation and VEGF up-regulation are important factors for the alteration of the pericyte structural protein desmin.
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Affiliation(s)
- Xiaorui Shi
- Department of Otolaryngology and Head and Neck Surgery, Oregon Hearing Research Center, Oregon Health and Science University, Portland, Oregon 97239-3098, USA. Institute of Microcirculation, Chinese Academy of MedicalSciences (CAMS) & Peking Union Medical College(PUMC), 5 Dong Dan San Tiao, Beijing, 100005, China.
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88
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Liu YP, Seçkin H, Izci Y, Du ZW, Yan YP, Başkaya MK. Neuroprotective effects of mesenchymal stem cells derived from human embryonic stem cells in transient focal cerebral ischemia in rats. J Cereb Blood Flow Metab 2009; 29:780-91. [PMID: 19209181 DOI: 10.1038/jcbfm.2009.1] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Embryonic mesenchymal stem cells (eMSCs) were first derived from human embryonic stem cells (hESCs) overexpressing green fluorescence protein (GFP). They expressed CD29, CD44, CD73, CD105, CD166 and nestin, but not CD34, CD45, CD106 SSEA-4 or Oct3/4. Twenty million eMSCs in 1 mL of phosphate-buffered saline (PBS) were injected into the femoral veins of spontaneously hypertensive rats after transient middle cerebral artery occlusion. The migration and differentiation of the eMSCs in the ischemic brain were analyzed. The results revealed that eMSCs migrated to the infarction region and differentiated into neurons, which were positive for beta-tubulin III, microtubule-associated protein 2 (MAP2), HuC, neurofilament and human nuclear antibody, and to vascular endothelial cells, which were positive for von Willebrand factor (vWF). The transplanted cells survived in the infarction region for at least 4 weeks. Adhesive removal function significantly improved in the first week after cell transplantation, and rotarod motor function significantly improved starting from the second week. The infarction volume in the eMSC group was significantly smaller than that in the PBS control group at 4 weeks after infusion. The results of this study show that when administered intravenously, eMSCs differentiated into neuronal and endothelial cells, reduced the infarction volume, and improved behavioral functional outcome significantly in transient focal cerebral ischemia.
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Affiliation(s)
- Yi-Ping Liu
- Department of Neurological Surgery, School of Medicine and Public Health University of Wisconsin-Madison, Madison, Wisconsin 53792, USA
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89
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Abstract
Recent reports have shown that bone marrow-derived cells (BMDCs) contribute to the formation of vasculature after stroke. However, the mechanism by which mural cells are formed from BMDC remains elusive. Here, we provide direct evidence that the cell fusion process contributes to the formation of pericytes after stroke. We generated mouse bone marrow chimeras using a cre/lox system that allows the detection of fusion events by X-gal staining. In these mice, we detected X-gal-positive cells that expressed vimentin and desmin, specific markers of mature murine pericytes. Electron microscopy confirmed that fused cells possessed basal lamina and characteristics of pericytes. Furthermore, induction of stroke increased significantly the presence of fused cells in the ischemic area. These cells expressed markers of developing pericytes such as NG2. We conclude that cell fusion participates actively in the generation of vascular tissue through pericyte formation under normal as well as pathologic conditions.
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90
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Rosenberg GA. Matrix metalloproteinases and their multiple roles in neurodegenerative diseases. Lancet Neurol 2009; 8:205-16. [DOI: 10.1016/s1474-4422(09)70016-x] [Citation(s) in RCA: 369] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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91
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Veeravagu A, Bababeygy SR, Kalani MYS, Hou LC, Tse V. The Cancer Stem Cell–Vascular Niche Complex in Brain Tumor Formation. Stem Cells Dev 2008; 17:859-67. [DOI: 10.1089/scd.2008.0047] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Affiliation(s)
- Anand Veeravagu
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California
| | - Simon R. Bababeygy
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California
| | - M. Yashar S. Kalani
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California
| | - Lewis C. Hou
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California
| | - Victor Tse
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California
- Department of Neurosurgery, Santa Clara Valley Medical Center, San Jose, California
- Providence Regional Medical Center, Everett and Seattle Neuroscience Institute at Swedish, Washington
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92
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Roitbak T, Li L, Cunningham LA. Neural stem/progenitor cells promote endothelial cell morphogenesis and protect endothelial cells against ischemia via HIF-1alpha-regulated VEGF signaling. J Cereb Blood Flow Metab 2008; 28:1530-42. [PMID: 18478024 PMCID: PMC3018350 DOI: 10.1038/jcbfm.2008.38] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Vascular cells provide a neural stem/progenitor cell (NSPC) niche that regulates expansion and differentiation of NSPCs within the germinal zones of the embryonic and adult brain under both physiologic and pathologic conditions. Here, we examined the NSPC-endothelial cell (NSPC/EC) interaction under conditions of ischemia, both in vitro and after intracerebral transplantation. In culture, embryonic mouse NSPCs supported capillary morphogenesis and protected ECs from cell death induced by serum starvation or by transient oxygen and glucose deprivation (OGD). Neural stem/progenitor cells constitutively expressed hypoxia-inducible factor 1alpha (HIF-1alpha) transcription factor and vascular endothelial growth factor (VEGF), both of which were increased approximately twofold after the exposure of NSPCs to OGD. The protective effects of NSPCs on ECs under conditions of serum starvation and hypoxia were blocked by pharmacological inhibitors of VEGF signaling, SU1498 and Flt-1-Fc. After intracerebral transplantation, NSPCs continued to express HIF-1alpha and VEGF, and promoted microvascular density after focal ischemia. These studies support a role for NSPCs in stabilization of vasculature during ischemia, mediated via HIF-1alpha-VEGF signaling pathways, and suggest therapeutic application of NSPCs to promote revascularization and repair after brain injury.
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Affiliation(s)
- Tamara Roitbak
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131-0001, USA
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93
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Abstract
It is common knowledge that ischemic stroke has major social and economic consequences. However, until now, translation of experimental studies into clinical reality has been sorely lacking. So far, most studies have focused on acute stroke outcome and early treatment paradigms affording neuroprotection. It is increasingly recognized that it will be necessary to harness the capacity of the brain for neuroregeneration to improve longer-term outcome. Endothelial nitric oxide synthase (eNOS) is emerging as a key target in molecular stroke research. eNOS ameliorates acute ischemic injury and promotes recovery following cerebral ischemia. This review summarizes the effects of eNOS on the regulation of cerebral blood flow, hemostasis, inflammation, angiogenesis as well as neurogenesis. The possible impact on stroke prevention as well as on strategies aimed at improving long-term stroke outcome are discussed.
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Affiliation(s)
- Karen Gertz
- Charité Universitätsmedizin Berlin, Klinik und Poliklinik für Neurologie, Abteilung für Experimentelle Neurologie, Charitéplatz 1, 10117 Berlin, Germany
| | - Matthias Endres
- Charité Universitätsmedizin Berlin, Klinik und Hochschulambulanz für Neurologie und Klinische Neurophysiologie, Campus Benjamin Franklin and Center for Stroke Research Berlin, Charitéplatz 1, 10117 Berlin, Germany
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94
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Rouleau C, Mersel M, de Weille J, Rakotoarivelo C, Fabre C, Privat A, Langley K, Petite D. A human spinal cord cell promotes motoneuron survival and maturation in vitro. J Neurosci Res 2008; 87:50-60. [PMID: 18752296 DOI: 10.1002/jnr.21835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Primary cultures of motoneurons represent a good experimental model for studying mechanisms underlying certain spinal cord pathologies, such as amyotrophic lateral sclerosis and spinal bulbar muscular atrophy (Kennedy's disease). However, a major problem with such culture systems is the relatively short cell survival times, which limits the extent of motoneuronal maturation. In spite of supplementing culture media with various growth factors, it remains difficult to maintain motoneurons viable longer than 10 days in vitro. This study employs a new approach, in which rat motoneurons are plated on a layer of cultured cells derived from newborn human spinal cord. For all culture periods, more motoneurons remain viable in such cocultures compared with control monocultures. Moreover, although no motoneurons survive in control cultures after 22 days, viable motoneurons were observed in cocultures even after 7 weeks. Although no significant difference in neurite length was observed between 8-day mono- and cocultures, after 22 and 50 days in coculture motoneurons had a very mature morphology. They extended extremely robust, very long neurites, which formed impressive branched networks. Data obtained using a system in which the spinal cord cultures were separated from motoneurons by a porous polycarbonate filter suggest that soluble factors released from the supporting cells are in part responsible for the beneficial effects on motoneurons. Several approaches, including immunocytochemistry, immunoblotting, and electron microscopy, indicated that these supporting cells, capable of extending motoneuron survival and enhancing neurite growth, had an undifferentiated or poorly differentiated, possibly mesenchymal phenotype.
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95
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Treatment of stroke with (Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl) amino] diazen-1-ium-1, 2-diolate and bone marrow stromal cells upregulates angiopoietin-1/Tie2 and enhances neovascularization. Neuroscience 2008; 156:155-64. [PMID: 18691637 DOI: 10.1016/j.neuroscience.2008.07.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 07/07/2008] [Accepted: 07/08/2008] [Indexed: 01/12/2023]
Abstract
Neovascularization may contribute to functional recovery after neural injury. Combination treatment of stroke with a nitric oxide donor, (Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl) amino] diazen-1-ium-1, 2-diolate (DETA-NONOate) and bone marrow stromal cells promotes functional recovery. However, the mechanisms underlying functional improvement have not been elucidated. In this study, we tested the hypothesis that combination treatment upregulates angiopoietin-1 and its receptor Tie2 in the ischemic brain and bone marrow stromal cells, thereby enhancing cerebral neovascularization after stroke. Adult wild type male C57BL/6 mice were i.v. administered PBS, bone marrow stromal cells 5x10(5), DETA-NONOate 0.4 mg/kg or combination DETA-NONOate with bone marrow stromal cells (n=12/group) after middle cerebral artery occlusion. Combination treatment significantly upregulated angiopoietin-1/Tie2 and tight junction protein (occludin) expression, and increased the number, diameter and perimeter of blood vessels in the ischemic brain compared with vehicle control (mean+ or -S.E., P<0.05). In vitro, DETA-NONOate significantly increased angiopoietin-1/Tie2 protein (n=6/group) and Tie2 mRNA (n=3/group) expression in bone marrow stromal cells. DETA-NONOate also significantly increased angiopoietin-1 protein (n=6/group) and mRNA (n=3/group) expression in mouse brain endothelial cells (P<0.05). Angiopoietin-1 mRNA (n=3/group) was significantly increased in mouse brain endothelial cells treated with DETA-NONOate in combination with bone marrow stromal cell-conditioned medium compared with cells treated with bone marrow stromal cell-conditioned medium or DETA-NONOate alone. Mouse brain endothelial cell capillary tube-like formation assays (n=6/group) showed that angiopoietin-1 peptide, the supernatant of bone marrow stromal cells and DETA-NONOate significantly increased capillary tube formation compared with vehicle control. Combination treatment significantly increased capillary tube formation compared with DETA-NONOate treatment alone. Inhibition of angiopoietin-1 significantly attenuated combination treatment-induced tube formation. Our data indicated that combination treatment of stroke with DETA-NONOate and bone marrow stromal cells promotes neovascularization, which is at least partially mediated by upregulation of the angiopoietin-1/Tie2 axis.
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96
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Benton RL, Maddie MA, Minnillo DR, Hagg T, Whittemore SR. Griffonia simplicifolia isolectin B4 identifies a specific subpopulation of angiogenic blood vessels following contusive spinal cord injury in the adult mouse. J Comp Neurol 2008; 507:1031-52. [PMID: 18092342 DOI: 10.1002/cne.21570] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
After traumatic spinal cord injury (SCI), disruption and plasticity of the microvasculature within injured spinal tissue contribute to the pathological cascades associated with the evolution of both primary and secondary injury. Conversely, preserved vascular function most likely results in tissue sparing and subsequent functional recovery. It has been difficult to identify subclasses of damaged or regenerating blood vessels at the cellular level. Here, adult mice received a single intravenous injection of the Griffonia simplicifolia isolectin B4 (IB4) at 1-28 days following a moderate thoracic (T9) contusion. Vascular binding of IB4 was maximally observed 7 days following injury, a time associated with multiple pathologic aspects of the intrinsic adaptive angiogenesis, with numbers of IB4 vascular profiles decreasing by 21 days postinjury. Quantitative assessment of IB4 binding shows that it occurs within the evolving lesion epicenter, with affected vessels expressing a temporally specific dysfunctional tight junctional phenotype as assessed by occludin, claudin-5, and ZO-1 immunoreactivities. Taken together, these results demonstrate that intravascular lectin delivery following SCI is a useful approach not only for observing the functional status of neovascular formation but also for definitively identifying specific subpopulations of reactive spinal microvascular elements.
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Affiliation(s)
- Richard L Benton
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky 40292, USA
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97
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Abstract
Stem cells have been the focus of numerous investigations to treat diseases as far ranging as diabetes, chronic heart failure and multiple sclerosis over the past decade. The process of stem-cell-based repair of acute injury involves homing and engrafting of the stem cell of interest to the site of injury followed by either differentiation of the stem cell to indigenous end-organ cells or liberation of paracrine factors that lead to preservation and/or optimization of organ function. Recognition of the ability of stem cells to home to sites of acute injury suggests that, if appropriately defined and harnessed, stem cell homing could serve as a means of local drug delivery through the infusion of genetically engineering stem cells that secrete gene products of interest. The authors have recently demonstrated the use of this approach in preclinical studies of acute myocardial function. In addition, the use of engineered cells that home to appropriate niches have been used to correct genetic deficiency states (i.e., severe combined immunodeficiency, diabetes mellitus) in patients with otherwise chronic debilitating diseases. This review focuses on exploiting stem cell homing for gene transfer and on the state of the art and the challenges that face the field.
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Affiliation(s)
- Marc S Penn
- Skirball Laboratory for Cardiovascular Cellular Therapeutics, Department of Cardiovascular Medicine, NE3, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
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98
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99
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Denes A, Vidyasagar R, Feng J, Narvainen J, McColl BW, Kauppinen RA, Allan SM. Proliferating resident microglia after focal cerebral ischaemia in mice. J Cereb Blood Flow Metab 2007; 27:1941-53. [PMID: 17440490 DOI: 10.1038/sj.jcbfm.9600495] [Citation(s) in RCA: 253] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cerebral ischaemia usually results in the rapid death of neurons within the immediate territory of the affected artery. Neuronal loss is accompanied by a sequence of events, including brain oedema, blood-brain barrier (BBB) breakdown, and neuroinflammation, all of which contribute to further neuronal death. Although the role of macrophages and mononuclear phagocytes in the expansion of ischaemic injury has been widely studied, the relative contribution of these cells, either of exogenous or intrinsic central nervous system (CNS) origin is still not entirely clear. The purpose of this study, therefore, was to use different durations of transient middle cerebral artery occlusion (tMCAo) in the mouse to investigate fully post-occlusion BBB permeability and cellular changes in the brain during the 72 h post-MCAo period. This was achieved using in vivo magnetic resonance imaging (MRI) and cell labelling techniques. Our results show that BBB breakdown and formation of the primary ischaemic damage after tMCAo is not associated with significant infiltration of neutrophils, although more are observed with longer periods of MCAo. In addition, we observe very few infiltrating exogenous macrophages over a 72 h period after 30 or 60 mins of occlusion, instead a profound increase in proliferating resident microglia cells was observed. Interestingly, the more severe injury associated with 60 mins of MCAo leads to a markedly reduced proliferation of resident microglial cells, suggesting that these cells may play a protective function, possibly through phagocytosis of infiltrating neutrophils. These data further support possible beneficial actions of microglial cells in the injured brain.
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Affiliation(s)
- Adam Denes
- Laboratory of Molecular Neuroendocrinology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
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100
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Ohab JJ, Carmichael ST. Poststroke neurogenesis: emerging principles of migration and localization of immature neurons. Neuroscientist 2007; 14:369-80. [PMID: 18024854 DOI: 10.1177/1073858407309545] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Stroke induces proliferation of newly born neurons in the subventricular zone, migration of these immature neurons away from the SVZ, and localization within peri-infarct tissues. These 3 processes of proliferation, migration, and localization constitute distinct spatial and temporal zones within poststroke neurogenesis with distinct molecular and cell-cell signaling environments. Immature neurons migrate after stroke in close association with blood vessels and astrocytic processes, in a process that involves matrix metalloproteinases. This poststroke migration shares similar features with normal neuroblast migration in the rostral migratory stream. Immature neurons localize in the peri-infarct cortex in a neurovascular niche where neurogenesis is causally linked to angiogenesis through the vascular factors SDF-1 and angiopoietin-1. Other vascular and neuronal growth factors have also been linked to poststroke neuroblast localization in peri-infarct tissue, including erythropoietin. Most data on poststroke neurogenesis derive from laboratory rodents, which may have an abnormal or blunted degree of neurogenesis and neuroplasticity compared to normal, wild rodents. This will likely affect translational application of the principles of poststroke neurogenesis from mouse to man.
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Affiliation(s)
- J J Ohab
- David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA
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