Stromal cell

A critical step in radioprotection involves the IL-1 receptors. Monoclonal antibodies to the type 1 IL-1 receptor block IL-l-induced radioprotection (167). Although this receptor is not present on BM cells, it is present on fibroblasts, which suggests that the effects of IL-1 on stem cells maybe largely indirect and mediated by stromal cell activation (168). Anti-IL-1 receptor (type 1) also sensitizes normal mice to the effects of TBI, which suggests that endogenous IL-1 has an intrinsic radioprotective role. IL-6 induction by IL-1, but not CSF levels, is inhibited, which supports the concept that G-CSF and GM-CSF are insufficient by themselves at radioprotecting stem cells and indicates a contributory role for IL-6. Anti-IL-6 antibody blocks IL-1 and TNF-induced radioprotection and also decreases the intrinsic radioresistance of mice, as does anti-TNF- a (169). 

Osteoblasts are the primary cells responsible for bone formation. They are derived from mesenchymal (stromal) cells that first differentiate into pre-osteoblasts and then into mature, bone matrix producing osteoblasts. Inactivated or resting osteoblasts become lining cells and thus a reservoir for bone forming cells to be activated at the next remodelling cycle. Osteoblasts trapped and embedded in the mineralised matrix are called osteocyts, and are important for many properties of living bone. 

EDI), and water to produce a group of biodegradable PU foams. The interconnected pores varied in size from 10 to 2 mm in diameter. Rabbit bone-marrow stromal cells cultured on the materials for up to 30 days formed multilayers of confluent cells and were phenotypically similar to those grown on tissue culture PS. It supported the adherence and proliferation of both bone-marrow stromal cells and chondrocytes in vitro. In subdermal implants the investigators found that the material showed infiltration of both vascular cells and connective tissue. 

McQuibban GA, Butler GS, Gong JH, Bendall L, Power C, Clark-Lewis I, Overall CM (2001) Matrix metalloproteinase activity inactivates the CXC chemokine stromal cell-derived factor-1. J Biol Chem 276 43503 3508... 

HIV strains are grouped according to the preferred site of replication. T-tropic viruses prefer replication in T lymphocytes and M-tropic viruses in macrophages. Use of chemokine receptors differs for each subgroup CXCR4 (or fusin, the receptor for stromal cell-derived factor [SDF-1]) for T-tropic viruses and CCR5 (the receptor... 

Aiuti A, Turchetto L, Cota M, Cipponi A, Brambilla A, Arcelloni C, Paroni R, Vicenzi E, Bordignon C, Poh G (1999) Human CD34(+) cells express CXCR4 and its ligand stromal cell-derived factor-1. Implications for infection by T-ceU tropic human immunodeficiency virus. Blood 94(l) 62-73... 

D Apuzzo M, Relink A, Loetscher M, Hoxie JA, Clark-Lewis I, Melchers F, Baggiolini M, Moser B (1997) The chemokine SDF-1, stromal cell-derived factor 1, attracts early stage B cell precursors via the chemokine receptor CXCR4. Eur J Immunol 27 1788-1793 Dawson VL, Dawson TM, Uhl GR, Snyder SH (1993) Human immunodeficiency virus type 1 coat protein neurotoxicity mediated by nitric oxide in primary cortical cultures. Proc Natl Acad Sci USA 90 3256-3259... 

Langford D, Sanders VJ, Mallory M, Kaul M, Masliah E (2002) Expression of stromal cell-derived factor 1 alpha protein in HIV encephalitis. J Neuroimmunol 127 115-126... 

Nanki T, Lipsky PE (2000) Cutting edge stromal cell-derived factor-1 is a costimulator for CD4-I-T cell activation. J Immunol 164 5010-5014... 

Ajami K, Pitman MR, Wilson CH et al (2008) Stromal cell-derived factors lalpha and Ibeta, inflammatory protein-10 and interferon-inducible T cell chemo-attractant are novel substrates of dipeptidyl peptidase 8. FEBS Lett 582 819-825 Albright AV, Shieh JT, O Connor Ml et al (2000) Characterization of cultured microglia that can be infected by HIV-1. J Neurovirol 6(Suppl 1) S53-S60 Allen SJ, Crown SE, Handel TM (2007) Chemokine receptor structure, interactions, and antagonism. Annu Rev Immunol 25 787-820... 

Crump MP, Gong JH, Loetscher P et al (1997) Solution structure and basis for functional activity of stromal cell-derived factor-1 dissociation of CXCR4 activation from binding and inhibition of HIV-1. EMBO J 16 6996-7007... 

Culley FJ, Brown A, Conroy DM et al (2000) Eotaxin is specifically cleaved by hookworm metal-loproteases preventing its action in vitro and in vivo. J Immunol 165 6447-6453 Davis DA, Singer KE, De La Luz Sierra M et al (2005) Identification of carboxypeptidase N as an enzyme responsible for C-terminal cleavage of stromal cell-derived factor-lalpha in the circulation. Blood 105 4561 568... 

Zhang K, McQuibban GA, Silva C et al (2003) HIV-induced metalloproteinase processing of the chemokine stromal cell derived factor-1 causes neurodegeneration. Nat Neurosci 6 1064-1071... 

Ohtani Y, Minami M, Kawaguchi N, Nishiyori A, Yamamoto J, Takami S, Satoh M (1998) Expression of stromal cell-derived factor-1 and CXCR4 chemokine receptor mRNAs in cultured rat glial and neuronal cells. Neurosci Lett 249 163-166... 

Chalasani SH, Baribaud F, Coughlan CM, Sunshine MJ, Lee VM, Dorns RW, Littman DR, Raper JA (2003a) The chemokine stromal cell-derived factor-1 promotes the survival of embryonic retinal ganglion cells. J Neurosci 23 4601-4612... 

Chalasani SH, Sabol A, Xu H, Gyda MA, Rasband K, Granato M, Chien CB, Raper JA (2007) Stromal cell-derived factor-1 antagonizes slit/robo signaling in vivo. J Neurosci 27 973-980... 

Gong X, He X, Qi L, Zuo H, Xie Z (2006) Stromal cell derived factor-1 acutely promotes neural progenitor cell proliferation in vitro by a mechanism involving the ERKl/2 and P1-3K signal pathways. Cell Biol Int 30 466-471... 

Huttenrauch F, Nitzki A, Lin FT, Honing S, Oppermann M (2002) Beta-arrestin binding to CC chemokine receptor 5 requires multiple C-terminal receptor phosphorylation sites and involves a conserved Asp-Arg-Tyr sequence motif. J Biol Chem 277 30769-30777 Imitola J, Raddassi K, Park KI, Mueller FJ, Nieto M, Teng YD, Frenkel D, Li J, Sidman RL, Walsh CA, Snyder EY, Khoury SJ (2004) Directed migration of neural stem cells to sites of CNS injury by the stromal cell-derived factor lalpha/CXC chemokine receptor 4 pathway. Proc Natl Acad Sci U S A 101 18117-18122... 

Peng H, Huang Y, Rose J, Eiichsen D, Herek S, Fuji N, Tamamura H, Zheng J (2004) Stromal cell-derived factor 1-mediated CXCR4 signaling in rat and human cortical neural progenitor cells. J Neurosci Res 76 35-50... 

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