Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:3.2.1.23 (beta-galactosidase)
14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endothelial cells form the inner lining of blood and lymphatic vessels. In mice, only tumors of the blood vessel endothelium (haemangiomas) have been thus far reported. Here we describe a highly reproducible method for the induction of benign tumors of the lymphatic endothelial cells (lymphangiomas) in mice by intraperitoneal injection of incomplete Freund's adjuvant. Morphological and histopathological studies of the lesions revealed the presence of cells at various levels of vascular development. The lymphangiomas developed in the peritoneal cavity and expressed the endothelial markers CD31/PECAM (platelet endothelial cell adhesion molecule), CD54/ICAM-1 (InterCellular Adhesion Molecule-1), and CD102/ICAM-2, as well as the vascular endothelial growth factor (VEGF) receptor Flk-1, the endothelial cell specific receptors Tie-1 and Tie-2 and the lymphatic endothelial cell specific Flt4 receptor as shown by in situ hybridization. The Flk-1 and Flt4 receptors were also identified in immunoblots of the tumors and in cells cultured from them. When induced in beta-galactosidase knock-in Flt4(+/-) mice, the tumor endothelia could be stained blue in a number of tumor cells although the staining was of lower intensity than in normal lymphatic vessels. The tumor-derived cells could be propagated in vitro and they spontaneously differentiated, forming vessel-like structures. Murine lymphangiomas thus represent a highly reproducible and convenient source of lymphatic endothelial cells.
...
PMID:Lymphatic endothelial tumors induced by intraperitoneal injection of incomplete Freund's adjuvant. 992 52

Endothelial progenitor cells (EPCs) have been isolated from circulating mononuclear cells in human peripheral blood and shown to be incorporated into foci of neovascularization, consistent with postnatal vasculogenesis. We determined whether endogenous stimuli (tissue ischemia) and exogenous cytokine therapy (granulocyte macrophage-colony stimulating factor, GM-CSF) mobilize EPCs and thereby contribute to neovascularization of ischemic tissues. The development of regional ischemia in both mice and rabbits increased the frequency of circulating EPCs. In mice, the effect of ischemia-induced EPC mobilization was demonstrated by enhanced ocular neovascularization after cornea micropocket surgery in mice with hindlimb ischemia compared with that in non-ischemic control mice. In rabbits with hindlimb ischemia, circulating EPCs were further augmented after pretreatment with GM-CSF, with a corresponding improvement in hindlimb neovascularization. There was direct evidence that EPCs that contributed to enhanced corneal neovascularization were specifically mobilized from the bone marrow in response to ischemia and GM-CSF in mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase transcriptionally regulated by the endothelial cell-specific Tie-2 promoter. These findings indicate that circulating EPCs are mobilized endogenously in response to tissue ischemia or exogenously by cytokine therapy and thereby augment neovascularization of ischemic tissues.
...
PMID:Ischemia- and cytokine-induced mobilization of bone marrow-derived endothelial progenitor cells for neovascularization. 1020 35

Circulating endothelial progenitor cells (EPCs) have been isolated in peripheral blood of adult species. To determine the origin and role of EPCs contributing to postnatal vasculogenesis, transgenic mice constitutively expressing beta-galactosidase under the transcriptional regulation of an endothelial cell-specific promoter (Flk-1/LZ or Tie-2/LZ) were used as transplant donors. Localization of EPCs, indicated by flk-1 or tie-2/lacZ fusion transcripts, were identified in corpus luteal and endometrial neovasculature after inductive ovulation. Mouse syngeneic colon cancer cells (MCA38) were implanted subcutaneously into Flk-1/LZ/BMT (bone marrow transplantation) and Tie-2/LZ/BMT mice; tumor samples harvested at 1 week disclosed abundant flk-1/lacZ and tie-2/lacZ fusion transcripts, and sections stained with X-gal demonstrated that the neovasculature of the developing tumor frequently comprised Flk-1- or Tie-2-expressing EPCs. Cutaneous wounds examined at 4 days and 7 days after skin removal by punch biopsy disclosed EPCs incorporated into foci of neovascularization at high frequency. One week after the onset of hindlimb ischemia, lacZ-positive EPCs were identified incorporated into capillaries among skeletal myocytes. After permanent ligation of the left anterior descending coronary artery, histological samples from sites of myocardial infarction demonstrated incorporation of EPCs into foci of neovascularization at the border of the infarct. These findings indicate that postnatal neovascularization does not rely exclusively on sprouting from preexisting blood vessels (angiogenesis); instead, EPCs circulate from bone marrow to incorporate into and thus contribute to postnatal physiological and pathological neovascularization, which is consistent with postnatal vasculogenesis.
...
PMID:Bone marrow origin of endothelial progenitor cells responsible for postnatal vasculogenesis in physiological and pathological neovascularization. 1043 64

In a transgenic model of ischemic cardiomyopathy in which monocytes are attracted to the myocardium by the targeted overexpression of monocyte chemoattractant protein-1 (MCP-1), we have observed the presence of endothelial NO synthase and platelet endothelial cell adhesion molecule-1-negative tunnels, occasionally containing blood-derived cells, that probe the cardiac tissue. Immunohistochemical data show that monocytes/macrophages (MCs/Mphs) drill tunnels using the broad-spectrum mouse macrophage metalloelastase. 5-Bromo-2'-deoxyuridine incorporation and neo-endothelial markers present in the microvasculature of MCP-1 mouse hearts suggest an active angiogenic process. Further studies will be required to establish that the MC-/Mph-drilled tunnels evolve to become capillaries, connected to the existing vessels and colonized by circulating endothelial cell progenitors. This possibility is supported by the availability of these cells, which is demonstrated by cell tagging with beta-galactosidase placed under an active endothelial Tie-2 promoter. This phenomenon might represent another mechanism, in addition to the secretion of the angiogenic factors, by which MCs/MPhs may participate in the elaboration of new blood vessels in adult tissues.
...
PMID:Contribution of monocytes/macrophages to compensatory neovascularization: the drilling of metalloelastase-positive tunnels in ischemic myocardium. 1096 28

The Bmx gene, a member of the Tec tyrosine kinase gene family, is known to be expressed in subsets of hematopoietic and endothelial cells. In this study, mice were generated in which the first coding exon of the Bmx gene was replaced with the lacZ reporter gene by a knock-in strategy. The homozygous mice lacking Bmx activity were fertile and had a normal life span without an obvious phenotype. Staining of their tissues using beta-galactosidase substrate to assess the sites of Bmx expression revealed strong signals in the endothelial cells of large arteries and in the endocardium starting between days 10.5 and 12.5 of embryogenesis and continuing in adult mice, while the venular endothelium showed a weak signal only in the superior and inferior venae cavae. Of the five known endothelial receptor tyrosine kinases tested, activated Tie-2 induced tyrosyl phosphorylation of the Bmx protein and both Tie-2 and vascular endothelial growth factor receptor 1 (VEGFR-1) stimulated Bmx tyrosine kinase activity. Thus, the Bmx tyrosine kinase has a redundant role in arterial endothelial signal transduction downstream of the Tie-2 and VEGFR-1 growth factor receptors.
...
PMID:Bmx tyrosine kinase has a redundant function downstream of angiopoietin and vascular endothelial growth factor receptors in arterial endothelium. 1141 42

Endothelial progenitor cells (EPCs) have been isolated from circulating mononuclear cells in peripheral blood and shown to incorporate into foci of neovascularization, consistent with postnatal vasculogenesis. These circulating EPCs are derived from bone marrow and are mobilized endogenously in response to tissue ischemia or exogenously by cytokine stimulation. We show here, using a chemotaxis assay of bone marrow mononuclear cells in vitro and EPC culture assay of peripheral blood from simvastatin-treated animals in vivo, that the HMG-CoA reductase inhibitor, simvastatin, augments the circulating population of EPCs. Direct evidence that this increased pool of circulating EPCs originates from bone marrow and may enhance neovascularization was demonstrated in simvastatin-treated mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase transcriptionally regulated by the endothelial cell-specific Tie-2 promoter. The role of Akt signaling in mediating effects of statin on EPCs is suggested by the observation that simvastatin rapidly activates Akt protein kinase in EPCs, enhancing proliferative and migratory activities and cell survival. Furthermore, dominant negative Akt overexpression leads to functional blocking of EPC bioactivity. These findings establish that augmented mobilization of bone marrow-derived EPCs through stimulation of the Akt signaling pathway constitutes a novel function for HMG-CoA reductase inhibitors.
...
PMID:HMG-CoA reductase inhibitor mobilizes bone marrow--derived endothelial progenitor cells. 1148 28

Until recently, it was generally accepted that the vascularization of solid tumors occurred exclusively through the sprouting and co-option from pre-existing blood vessels. Growing evidence now suggests that bone marrow-derived endothelial progenitor cells (EP) circulate in the blood and may play an important role in the formation of new blood vessels in certain tumors. Whether endothelial progenitors participate in the vascularization of brain tumors has not yet been evaluated. In this study, we examined the contribution of EP to tumor angiogenesis in a murine glioma tumor model. Donor bone marrow cells obtained from transgenic mice constitutively expressing beta-galactosidase or GFP either ubiquitously or transcriptionally regulated by an endothelial specific promotor Tie-2 were injected into lethally irradiated adult mice. After bone marrow reconstitution by donor cells, mice were implanted with syngeneic GL261 murine glioma cells. Morphological and confocal 3-dimensional analysis showed that the majority of the engrafted donor marrow cells were expressing hematopoietic and/or microglia markers, but did not appreciably contribute to the tumor vasculature. Implantation of glioma cells genetically engineered to overexpress VEGF produced highly vascularized tumors. However, the number of endothelial progenitors incorporated in the tumor vasculature did not increase. These data strongly suggest that neovascularization in the brain might fundamentally be regulated by the sprouting of pre-existing vessels and implicate that circulating endothelial progenitors do not play a significant role in this process.
...
PMID:Minor contribution of bone marrow-derived endothelial progenitors to the vascularization of murine gliomas. 1465 62

Targeting of cells to specific tissues is critical for cell therapy. To study endothelial cell targeting, we isolated mouse liver sinusoidal endothelial cells (LSEC) and examined cell biodistributions in animals. To identify transplanted LSEC in tissues, we labeled cells metabolically with DiI-conjugated acetylated low density lipoprotein particles (DiI-Ac-LDL) or (111)Indium-oxine, used LSEC from Rosa26 donors expressing beta-galactosidase or Tie-2-GFP donors with green fluorescent protein (GFP) expression, and tranduced LSEC with a GFP-lentiviral vector. LSEC efficiently incorporated (111)Indium and DiI-Ac-LDL and expressed GFP introduced by the lentiviral vector. Use of radiolabeled LSEC showed differences in cell biodistributions in relation to the cell transplantation route. After intraportal injection, LSEC were largely in the liver (60 +/- 13%) and, after systemic intravenous injection, in lungs (67 +/- 9%); however, after intrasplenic injection, only some LSEC remained in the spleen (29 +/- 10%; P < .01), whereas most LSEC migrated to the liver or lungs. Transplanted LSEC were found in the liver, lungs, and spleen shortly after transplantation, whereas longer-term cell survival was observed only in the liver. Transplanted LSEC were distinct from Kupffer cells with expression of Tie-2 promoter-driven GFP and of CD31, without F4/80 reactivity. In further studies using radiolabeled LSEC, we established that the manipulation of receptor-mediated cell adhesion in liver sinusoids or the manipulation of blood flow-dependent cell exit from sinusoids improved intrahepatic retention of LSEC to 89 +/- 7% and 89 +/- 5%, respectively (P < .01). In conclusion, the targeting of LSEC to the liver and other organs is directed by vascular bed-specific mechanisms, including blood flow-related processes, and cell-specific factors. These findings may facilitate analysis of LSEC for cell and gene therapy applications.
...
PMID:Hepatic targeting of transplanted liver sinusoidal endothelial cells in intact mice. 1591 58

Estrogen has been demonstrated to promote therapeutic reendothelialization after vascular injury by bone marrow (BM)-derived endothelial progenitor cell (EPC) mobilization and phenotypic modulation. We investigated the primary hypothesis that estrogen regulates physiological postnatal vasculogenesis by modulating bioactivity of BM-derived EPCs through the estrogen receptor (ER), in cyclic hormonally regulated endometrial neovascularization. Cultured human EPCs from peripheral blood mononuclear cells (PB-MNCs) disclosed consistent gene expression of ER alpha as well as downregulated gene expressions of ER beta. Under the physiological concentrations of estrogen (17beta-estradiol, E2), proliferation and migration were stimulated, whereas apoptosis was inhibited on day 7 cultured EPCs. These estrogen-induced activities were blocked by the receptor antagonist, ICI182,780 (ICI). In BM transplanted (BMT) mice with ovariectomy (OVX) from transgenic mice overexpressing beta-galactosidase (lacZ) regulated by an endothelial specific Tie-2 promoter (Tie-2/lacZ/BM), the uterus demonstrated a significant increase in BM-derived EPCs (lacZ expressing cells) incorporated into neovasculatures detected by CD31 immunohistochemistry after E2 administration. The BM-derived EPCs that were incorporated into the uterus dominantly expressed ER alpha, rather than ER beta in BMT mice from BM of transgenic mice overexpressing EGFP regulated by Tie-2 promoter with OVX (Tie-2/EGFP/BMT/OVX) by ERs fluorescence immunohistochemistry. An in vitro assay for colony forming activity as well as flow cytometry for CD133, CD34, KDR, and VE-cadherin, using human PB-MNCs at 5 stages of the female menstrual-cycle (early-proliferative, pre-ovulatory, post-ovulatory, mid-luteal, late-luteal), revealed cycle-specific regulation of EPC kinetics. These findings demonstrate that physiological postnatal vasculogenesis involves cyclic, E2-regulated bioactivity of BM-derived EPCs, predominantly through the ER alpha.
...
PMID:Estrogen-mediated endothelial progenitor cell biology and kinetics for physiological postnatal vasculogenesis. 1765 79

We investigated whether administration of estradiol to male mice augments mobilization of bone marrow-derived endothelial progenitor cells (EPC) and incorporation into foci of neovascularization after hind-limb ischemia, thereby contributing to blood flow restoration. Mice were randomized and implanted with placebo pellets or pellets containing low-dose estradiol (0.39 mg) or high-dose estradiol (1.7 mg). Hind-limb ischemia was induced by unilateral resection of the left femoral artery 1 week after pellet implantation, then EPC mobilization and functional recovery was evaluated. EPC recruitment was assessed in mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase driven by the Tie-2 promoter. EPC culture assay performed 2 weeks after pellet implantation revealed a significantly greater (p<0.05) number of circulating EPCs in the high-dose estradiol group than in the low-dose estradiol and placebo groups. At 3 and 4 weeks after induction of hind-limb ischemia, perfusion was significantly greater (p<0.05) in high-dose estradiol mice than in mice implanted with the low-dose estradiol or placebo pellets. At 1 and 4 weeks after hind-limb ischemia surgery, more bone marrow-derived EPCs, identified as beta-galactosidase-positive cells, were observed in ischemic regions from high-dose estradiol animals than in low-dose (p<0.05) or placebo groups (p<0.05). These results indicate that estradiol dose-dependently increases the levels of EPCs in peripheral blood in male animals, improves the recovery of blood flow, and decreases limb necrosis after hind-limb ischemia, and that this enhancement occurs, in part, through augmentation of EPC mobilization and greater incorporation of bone marrow-derived EPCs into foci of neovascularization.
...
PMID:Estradiol-induced, endothelial progenitor cell-mediated neovascularization in male mice with hind-limb ischemia. 1914 77


1

---