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GFP+ Cells (gfp+ + cell)
Selected AbstractsFibroblast elongation and dendritic extensions in constrained versus unconstrained microtissuesCYTOSKELETON, Issue 3 2009Dylan M. Dean Abstract Cytoskeletal tension is fundamental to many biological processes, including germ layer sorting during embryogenesis [Krieg et al., 2008]. In vitro, such tension influences cell sorting in self-assembled, 3D microtissues and can be of sufficient magnitude to cause complex-shaped microtissue failure [Dean et al., 2007]. To examine the process of failure under cell-derived tension, we subjected normal human fibroblasts (NHFs) to directed self-assembly [Dean et al., 2007] in micro-molds designed to yield self-constraining microtissues. As cells contracted in this assay, the constrained microtissues narrowed, thinned and ultimately failed at their midpoints. By adding small numbers of GFP+ cells, changes in cell movement and morphology were assessed and compared to those of unconstrained microtissues. We found that cells formed numerous dendritic extensions within an hour of self-assembly and retracted these extensions as they elongated up to 30 times their initial diameter (,600 ,m) just prior to failure. Surprisingly, significant coordination in cell motility was observed over large distances within microtissues. Pharmacologic interventions showed that failure was myosin II and Rho kinase dependent and inhibition of failure resulted in shorter cells with greater numbers of extensions. These findings further our understanding of cellular self-assembly and introduce the use of GFP+ cells with directed self-assembly as a scaffold-free analogue to fibroblast-populated collagen gels (FPCGs). Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source] The migratory behavior of immature enteric neuronsDEVELOPMENTAL NEUROBIOLOGY, Issue 1 2009M.M. Hao Abstract While they are migrating caudally along the developing gut, around 10%,20% of enteric neural crest-derived cells start to express pan-neuronal markers and tyrosine hydroxylase (TH). We used explants of gut from embryonic TH-green fluorescence protein (GFP) mice and time-lapse microscopy to examine whether these immature enteric neurons migrate and their mode of migration. In the gut of E10.5 and E11.5 TH-GFP mice, around 50% of immature enteric neurons (GFP+ cells) migrated, with an average speed of around 15 ,m/h. This is slower than the speed at which the population of enteric neural crest-derived cells advances along the developing gut, and hence neuronal differentiation seems to slow, but not necessarily halt, the caudal migration of enteric neural crest cells. Most migrating immature enteric neurons migrated caudally by extending a long-leading process followed by translocation of the cell body. This mode of migration is different from that of non-neuronal enteric neural crest-derived cells and neural crest cells in other locations, but resembles that of migrating neurons in many regions of the developing central nervous system (CNS). In migrating immature enteric neurons, a swelling often preceded the movement of the nucleus in the direction of the leading process. However, the centrosomal marker, pericentrin, was not localized to either the leading process or swelling. This seems to be the first detailed report of neuronal migration in the developing mammalian peripheral nervous system. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2009. [source] PDGF stimulates the massive expansion of glial progenitors in the neonatal forebrainGLIA, Issue 16 2009M. C. Assanah Abstract Platelet-derived growth factor (PDGF) plays a major role in regulating migration, proliferation, and differentiation of glial progenitors during normal brain development and in the abnormal proliferation and dispersion that drives the formation of malignant gliomas. To further explore the relationship between PDGF's effects on normal glial progenitors and its role in the formation of gliomas, we infected progenitor cells in the subventricular zone (SVZ) of the lateral ventricle of neonatal rat pups with a retrovirus that expresses PDGF and green fluorescent protein (GFP). At 3 days post-injection (dpi), a proliferation of PDGFR,+ progenitors was seen in the SVZ and white matter around the injection site and by 10 dpi the animals had large diffusely infiltrating tumors that resembled glioblastomas. The tumors contained a massive proliferation of both infected and uninfected PDGFR,+ progenitors, suggesting that PDGF was driving tumor formation via both autocrine and paracrine signaling. Rats co-injected with two retroviruses (one that expresses PDGF-IRES-DSRED and one that expresses only GFP) formed tumors that contained a mixture of DSRED+ cells (PDGF producers) and GFP+ cells (recruited progenitors). Time-lapse microscopy of slice cultures confirmed that both DSRED+ and GFP+ cells were highly migratory and proliferative. Furthermore, adding exogenous PDGF to slice cultures generated from nontumor-bearing brains (injected with control GFP retrovirus only) stimulated the migration and proliferation of GFP+ progenitors. These findings reveal the inherent growth factor responsiveness and tumorigenic potential of PDGFR,+ progenitors and highlight the importance of paracrine signaling in stimulating glioma growth and infiltration. © 2009 Wiley-Liss, Inc. [source] Genetic fate mapping of Olig2 progenitors in the injured adult cerebral cortex reveals preferential differentiation into astrocytesJOURNAL OF NEUROSCIENCE RESEARCH, Issue 16 2008Kouko Tatsumi Abstract Olig2 is a basic helix-loop-helix (bHLH) transcription factor essential for development of motoneurons and oligodendrocytes. It is known that Olig2+ cells persist in the central nervous system (CNS) from embryonic to adult stages and that the number of Olig2+ progenitors increases in the injured adult CNS. Recent studies have demonstrated an inhibitory action of Olig2 on neurogenesis in adult CNS, but the fate of Olig2+ cells in the injured state remains largely unknown. To trace directly the fate of Olig2 cells in the adult cerebral cortex after injury, we employed the CreER/loxP system to target the olig2 locus. In this genetic tracing study, green fluorescent protein (GFP) reporter-positive cells labeled after cryoinjury coexpressed glial fibrillary acidic protein (GFAP), an astrocytic marker. Electron microscopy also showed that GFP+ cells have the ultrastructural characteristics of astrocytes. Furthermore, GFP+ cells labeled before injury, most of which had been NG2 cells, also produced bushy astrocytes. Here we show direct evidence that Olig2+ cells preferentially differentiate into astrocytes, which strongly express GFAP, in response to injury in the adult cerebral cortex. These results suggest that reactive astrocytes, known to be the main contributors to glial scars, originate, at least in part, from Olig2+ cells. © 2008 Wiley-Liss, Inc. [source] Evidence of Temporary Airway Epithelial Repopulation and Rare Clonal Formation by BM-derived Cells Following Naphthalene Injury in MiceTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 9 2007Vladimir B. Serikov Abstract The goal of the study was to investigate participation of bone marrow (BM) cells in the process of airway epithelial restoration after naphthalene-induced injury. We transplanted sex-mismatched green fluorescent protein (GFP) -tagged BM-derived cultured plastic-adherent mesenchymal stem cells into 5Gy-irradiated C57BL/6 recipients. After 1 month of recovery, experimental animals were subjected to 250 mg/kg naphthalene IP. Animals were killed at 2,30 days after naphthalene. By immunofluorescence, immunohistochemistry, and by in situ hybridization for the Y-chromosome, we observed patches of donor-derived cells in the large and small conducting airways, mostly at 2,6 days after injury. GFP+ cells in the epithelium of airways were positive for pancytokeratin and some other epithelial markers. Although rare, GFP+ cells formed clear isolated patches of the bronchial epithelium, consistent with clonal formation; as some cells were also positive for proliferating cell nuclear antigen, a marker of proliferating cells. After day 12, only occasional GFP+ cells were present in the epithelium. These data confirm that bone marrow-derived cultured mesenchymal cells can participate in the recovery of the injured airway epithelium after naphthalene-induced injury with minimal long-term engraftment. Anat Rec, 2007. © 2007 Wiley-Liss, Inc. [source] Listeria monocytogenes -infected bone marrow myeloid cells promote bacterial invasion of the central nervous systemCELLULAR MICROBIOLOGY, Issue 2 2005Olivier F. Join-Lambert Summary Listeria monocytogenes is a facultative intracellular pathogen that is able to invade the central nervous system causing meningoencephalitis and brain abscesses. The mechanisms allowing bacteria to cross the blood,brain barrier are poorly understood. In this work, we used an experimental model of acute listeriosis in the mouse inducing a reproducible invasion of the central nervous system. At the early phase of infection, we find that bacteria invade and rapidly grow in bone marrow cells identified as bone marrow myelomonocytic cells expressing the phenotype CD31pos:Ly-6Cpos:CD11bpos:LY-6Glow. We demonstrate that central nervous system invasion is facilitated by injecting L. monocytogenes- infected bone marrow cells in comparison with free bacteria or infected spleen cells. In mice transplanted with bone marrow cells from transgenic donor mice expressing the green fluorescent protein (GFP), we show that infected myeloid GFP+ cells adhere to activated brain endothelial cells, accumulate in brain vessels and participate to the pathogenesis of meningoencephalitis and brain abscesses. Our results demonstrate that bone marrow, the main haematopoietic tissue, is a previously unrecognized reservoir of L. monocytogenes -infected myeloid cells, which can play a crucial role in the pathophysiology of meningoencephalitis by releasing infected cells into the circulation that ultimately invade the central nervous system. [source] | ||||||||||