β 1 Integrin-mediated Effects of Tenascin-R Domains EGFL and FN6-8 on Neural Stem/Progenitor Cell Proliferation and Differentiation in Vitro

Abstract

Neural stem/progenitor cells (NSCs) have the capacity for self-renewal and differentiation into major classes of central nervous system cell types, such as neurons, astrocytes, and oligodendrocytes. The determination of fate of NSCs appears to be regulated by both intrinsic and extrinsic factors. Mounting evidence has shown that extracellular matrix molecules contribute to NSC proliferation and differentiation as extrinsic factors. Here we explore the effects of the epidermal growth factor-like (EGFL) and fibronectin type III homologous domains 6-8 (FN6-8) of the extracellular matrix molecule tenascin-R on NSC proliferation and differentiation. Our results show that domain FN6-8 inhibited NSC proliferation and promoted NSCs differentiation into astrocytes and less into oligodendrocytes or neurons. The EGFL domain did not affect NSC proliferation, but promoted NSC differentiation into neurons and reduced NSC differentiation into astrocytes and oligodendrocytes. Treatment of NSCs with β 1 integrin function-blocking antibody resulted in attenuation of inhibition of the effect of FN6-8 on NSC proliferation. The influence of EGFL or FN6-8 on NSCs differentiation was inhibited byβ 1 integrin antibody application, implicatingβ 1 integrin in proliferation and differentiation induced by EGFL and FN6-8 mediated triggering of NSCs. Neural stem/progenitor cells (NSCs) have the capacity for self-renewal and differentiation into major classes of central nervous system cell types, such as neurons, astrocytes, and oligodendrocytes. The determination of fate of NSCs appears to be regulated by both intrinsic and extrinsic factors. Mounting evidence has shown that extracellular matrix molecules contribute to NSC proliferation and differentiation as extrinsic factors. Here we explore the effects of the epidermal growth factor-like (EGFL) and fibronectin type III homologous domains 6-8 (FN6-8) of the extracellular matrix molecule tenascin-R on NSC proliferation and differentiation. Our results show that domain FN6-8 inhibited NSC proliferation and promoted NSCs differentiation into astrocytes and less into oligodendrocytes or neurons. The EGFL domain did not affect NSC proliferation, but promoted NSC differentiation into neurons and reduced NSC differentiation into astrocytes and oligodendrocytes. Treatment of NSCs with β 1 integrin function-blocking antibody resulted in attenuation of inhibition of the effect of FN6-8 on NSC proliferation. The influence of EGFL or FN6-8 on NSCs differentiation was inhibited byβ 1 integrin antibody application, implicatingβ 1 integrin in proliferation and differentiation induced by EGFL and FN6-8 mediated triggering of NSCs. Extracelluar matrix (ECM) 4The abbreviations used are: ECM, extracellular matrix; bFGF, basic fibroblast growth factor; BrdUrd, 5-bromodeoxyuridine; EGF, epidermal growth factor; EGFL, epidermal growth factor-like repeats containing the NH2-terminal domain of TN-R; FCS, fetal calf serum; FN6-8, fibronectin-type III homologous repeats 6-8; GFAP, glial fibrillary acidic protein; GST, glutathione S-transferase; NSCs, neural stem/progenitor cells; PBS, phosphate-buffered saline; SVZ, subventricular zone; TN-R, tenascin-R; TN-C, tenascin-C; DMEM, Dulbecco's modified Eagle's medium. molecules in the central nervous system, are secreted from both neurons and glial cells and accumulate in the extracellular space (1Dityatey A. Schachner M. Cell Tissue Res. 2006; 326: 647-654Crossref PubMed Scopus (92) Google Scholar). ECM constituents play important roles in synaptic plasticity, formation of developmental compartments, and control of cell adhesion, migration, and differentiation (2Jankovski A. Sotelo C. J. Comp. Neurol. 1996; 371: 376-396Crossref PubMed Google Scholar, 3Steindler D.A. Kadrie T. Fillmore H. Thomas L.B. Prog. Brain Res. 1996; 108: 349-363Crossref PubMed Google Scholar, 4Scheffler B. Horn M. Blumcke I. Laywell E.D. Coomes D. Kukekov V.G. Steindler D.A. Trends Neurosci. 1999; 22: 348-357Abstract Full Text Full Text PDF PubMed Scopus (86) Google Scholar). Tenascin-R (TN-R) is an extracellular matrix glycoprotein, mainly expressed in the central nervous system and predominantly by differentiating oligodendrocytes as well as some interneurons in the spinal cord, retina, cerebellum, and hippocampus (5Pesheva P. Spiess E. Schachner M. J. Cell Biol. 1989; 109: 1765-1778Crossref PubMed Scopus (233) Google Scholar, 7Jones F.S. Jones P.L. Dev. Dyn. 2000; 218: 235-259Crossref PubMed Scopus (557) Google Scholar). TN-R contains a cysteine-rich amino-terminal region, epidermal growth factor-like repeats (EGFL), a region consisting of fibronectin type III (FN) homologous repeats, and a fibrinogen-like domain at the carboxyl terminus (Fig. 1) (8Fuss B. Wintergerst E.S. Bartsch U. Schachner M. J. Cell Biol. 1993; 120: 1237-1249Crossref PubMed Scopus (156) Google Scholar, 9Norenberg U. Hubert M. Rathjen F.G. Int. J. Dev. Neurosci. 1996; 14: 217-231Crossref PubMed Scopus (26) Google Scholar). TN-R is a multifunctional molecule with multiple domains that confer different effects on neuronal cell functions, such as neuronal cell adhesion, neurite outgrowth, modulation of sodium channels, and synaptic plasticity. The EGFL domain is anti-adhesive for microglia and hippocampal neurons, whereas the FN6-8 domain promotes adhesion of microglia or hippocampal neurons (10Lochter A. Schachner M. J. Neurosci. 1993; 13: 3986-4000Crossref PubMed Google Scholar, 14Liao H. Bu W.Y. Wang T.H. Ahmed S. Xiao Z.C. J. Biol. Chem. 2005; 280: 8316-8323Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar). In vivo experiments have shown that in TN-R-deficient mice functional recovery after spinal cord injury was better than in wild type control littermates, and cortical and hippocampal neuronal excitability were enhanced (13Saghatelyan A.K. Dityatev A. Schmidt S. Schuster T. Bartsch U. Schachner M. Mol. Cell. Neurosci. 2001; 17: 226-240Crossref PubMed Scopus (158) Google Scholar, 15Gurevicius K. Gureviciene I. Valjakka A. Schachner M. Tanila H. Mol. Cell. Neurosci. 2004; 25: 515-523Crossref PubMed Scopus (48) Google Scholar, 16Apostolova I. Irintchev A. Schachner M. J. Neurosci. 2006; 26: 7849-7859Crossref PubMed Scopus (132) Google Scholar). Our previous work has shown that TN-R plays a role in neuroprotection via domains EGFL and FN6-8 (14Liao H. Bu W.Y. Wang T.H. Ahmed S. Xiao Z.C. J. Biol. Chem. 2005; 280: 8316-8323Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar). We have further shown that TN-R is responsible for radial migration of NSCs of the rostral migratory stream by attracting NSCs to the olfactory bulb or, when TN-R secreting fibroblasts are transplanted into the striatum, NSCs are attracted to the source of TN-R expression and deviate from tangential migration by attraction to the TN-R source. The role of TN-R in NSC proliferation and differentiation has, however, not been explored. NSCs are mainly found in the subgranular layer of the dentate gyrus of the hippocampus and in the subventricular zone (SVZ) of the lateral ventricles in the adult mammalian central nervous system, where they have the capacity for self-renewal and differentiation into major classes of central nervous system cell types, such as neurons, astrocytes, and oligodendrocytes (17Gage F.H. Science. 2000; 287: 1433-1438Crossref PubMed Scopus (4114) Google Scholar, 19Lois C. Alvarez-Buylla A. Science. 1994; 264: 1145-1148Crossref PubMed Scopus (1977) Google Scholar). The most active neurogenic region and the richest source of NSCs is the SVZ of the forebrain, and from the SVZ, newly generated NSCs migrate long distances to reach their final position in the olfactory bulb according to a well defined path called the rostral migratory stream. Cells then shift their migration pattern from the tangential to the radial orientation and finally differentiate into neurons (18Luskin M.B. Neuron. 1993; 11: 173-189Abstract Full Text PDF PubMed Scopus (1610) Google Scholar, 20Alvarez-Buylla A. Garcia-Verdugo J.M. J. Neurosci. 2002; 22: 629-634Crossref PubMed Google Scholar, 21Pencea V. Bingaman K.D. Freedman L.J. Luskin M.B. Exp. Neurol. 2001; 172: 1-16Crossref PubMed Scopus (307) Google Scholar, 22Magavi S.S. Leavitt B.R. Macklis J.D. Nature. 2000; 405: 951-955Crossref PubMed Scopus (1107) Google Scholar). Much evidence has demonstrated the existence of a “niche,” a specialized microenvironment where stem cells are located in vivo and that contributes to NSC migration, proliferation, and differentiation as an extrinsic factor. Niches are composed of cells that affect NSC behavior by producing soluble factors (growth factors, chemokines, and neurotrophins), membrane-bound molecules, and ECM molecules. The developmental program of NSCs is regulated by these extrinsic factors (23Li L. Xie T. Annu. Rev. Cell Dev. Biol. 2005; 21: 605-631Crossref PubMed Scopus (951) Google Scholar, 24Moore K.A. Lemischka I.R. Science. 2006; 311: 1880-1885Crossref PubMed Scopus (1302) Google Scholar). ECM molecules in the SVZ are likely to control, at least in part, NSC behavior by instructive cues. For instance, TN-R mediates activity-dependent recruitment of neuroblasts in the adult mouse forebrain (25Saghatelyan A. Chevigny A. Schachner M. Lledo P.M. Nat. Neurosci. 2004; 7: 347-356Crossref PubMed Scopus (191) Google Scholar). In tenascin-C (TN-C)-deficient mice the rate of oligodendrocyte precursor cell migration increased and the rate of cell proliferation decreased (25Saghatelyan A. Chevigny A. Schachner M. Lledo P.M. Nat. Neurosci. 2004; 7: 347-356Crossref PubMed Scopus (191) Google Scholar, 26Garcion E. Faissner A. Ffrench-Constant C. Development. 2001; 128: 2485-2496Crossref PubMed Google Scholar). TN-C contributes to the generation of a stem cell niche within the SVZ, acting to orchestrate growth factor signaling so as to accelerate neural stem cell development (27Garcion E. Halilagic A. Faissner A. Ffrench-Constant C. Development. 2004; 131: 3423-3432Crossref PubMed Scopus (258) Google Scholar). However, the functions of distinct domains of TN-C or TN-R acting as extrinsic factors on NSC behavior have remained unclear. In particular, the molecular mechanisms of distinct TN-R domains have not been investigated with regard to their migration and differentiation into different neural cell types, such as neurons, astrocytes, and oligodendrocytes. Thus, we investigated the consequences of proliferation and differentiation of NSCs exposed to TN-R. For this study, we chose to investigate the EGFL and FN6-8 domains, because these domains have emerged as the most effective in modulation of functional properties of target cell types, such as neurons, in their capacity to generate neurites on a uniform substrate or being repelled at a boundary (11Xiao Z.C. Taylor J. Montag D. Rougon G. Schachner M. Eur. J. Neurosci. 1996; 8: 766-782Crossref PubMed Scopus (89) Google Scholar, 12Xiao Z.C. Hillenbrand R. Schachenr M. Thermes S. Rougon G. Gomez S. J. Neurosci. Res. 1997; 49: 698-709Crossref PubMed Scopus (18) Google Scholar, 28Lochter A. Vaughan L. Kaplony A. Prochiantz A. Schachner M. Faissner A. J. Cell Biol. 1991; 113: 1159-1171Crossref PubMed Scopus (249) Google Scholar, 30Husmann K. Faissner A. Schachner M. J. Cell Biol. 1992; 116: 1475-1486Crossref PubMed Scopus (170) Google Scholar). Furthermore, the EGFL domain is anti-adhesive for microglia, whereas the FN6-8 domain promotes adhesion of microglia, whereas domains FN1-2 and FN3-5 do not affect microglial adhesion (23Li L. Xie T. Annu. Rev. Cell Dev. Biol. 2005; 21: 605-631Crossref PubMed Scopus (951) Google Scholar). Our results show that both domains modulate NSC proliferation and differentiation via the cell surface receptor β 1 integrin. Preparation of Recombinant EGFL and FN6-8 Domains—Generation and purification of the recombinant EGFL and FN6-8 domains of mouse TN-R as fusion proteins with GST were performed as described (11Xiao Z.C. Taylor J. Montag D. Rougon G. Schachner M. Eur. J. Neurosci. 1996; 8: 766-782Crossref PubMed Scopus (89) Google Scholar), and the plasmids of pGEXEGFL and pGEX-FN6-8 were a kind gift of Dr. Zhi-Cheng Xiao (Singapore General Hospital, Singapore). The fusion proteins were analyzed for purity by SDS-PAGE (31Laemmli U.K. Nature. 1970; 277: 680-685Crossref Scopus (207537) Google Scholar) and shown to have a purity of at least 90%. Neural Stem Cell Culture—Sprague-Dawley rat embryos (E13-14 days) were stripped of meninges, and coronal sections (2 mm thick) of tissue containing the SVZ of the lateral ventricles were removed under a dissection microscope and mechanically dissociated into single cells. Cells were seeded into a 6-well plate (Costar), and maintained in DMEM/F-12 medium containing B27, bFGF (20 ng/ml), EGF (20 ng/ml) (all from Invitrogen), at 37 °C in an incubator with 5% CO2. Neurospheres formed within 3-5 days were dissociated mechanically into single cells and seeded into a new 6-well Neurospheres from to were used for Cells in the were for a for NSCs. of Neural Stem NSCs from were in DMEM/F-12 medium with B27, bFGF (20 ng/ml), and EGF (20 ng/ml) in the of GST fusion proteins EGFL, and FN6-8, or seeded with and GST fusion proteins EGFL, and FN6-8, for and was into the medium and cells were maintained at 37 °C in a incubator to and cell proliferation on was analyzed for by For the β 1 integrin after of cells with for 1 NSCs seeded were with a function-blocking β 1 integrin antibody or for 1 at 37 °C GST fusion proteins into the medium. experiments were of Neural Stem were dissociated mechanically into single cells and maintained in the DMEM/F-12 medium with and fetal calf at 37 °C in the incubator for days in the of GST fusion proteins EGFL, and FN6-8, or GST fusion proteins EGFL, and FN6-8, were cells were for expression to neurons, astrocytes, and oligodendrocytes by For the β 1 integrin after of cells with for 1 NSCs seeded with a function-blocking β 1 integrin antibody or for at GST fusion proteins into the medium. experiments were on were with PBS, with with in PBS, and with antibody in at °C with or antibody III and 1 integrin were were with For the cells were in for at in in medium cells were with an least cells from to were used to of cells. cell C. M. J. Neurosci. Res. 1996; PubMed Scopus Google Scholar) was used to the effect of EGFL on oligodendrocyte differentiation by Dr. Zhi-Cheng General Hospital, Singapore). Cells were in with and with for at 37 °C in an incubator with 5% CO2. The medium was then with containing FCS, and cells were maintained in the of EGFL and GST proteins cells were and analyzed for a of by GST and and were with of at °C for 1 to to the were then with the 1 integrin antibody for 1 at °C and then with of at were proteins were in of by and with antibody The β 1 integrin was as control by 1 integrin antibody For GST fusion proteins on were with NSC of at °C for proteins were by and for with 1 integrin GST antibody was used to investigate the GST fusion proteins as were analyzed by of and are expressed as was as FN6-8 of TN-R the of NSCs are of we the influence of TN-R EGFL and FN6-8 domains on NSC proliferation by the of into NSCs by of of NSCs in for or the of cells as by of was decreased by FN6-8, when with cells with medium on GST or (Fig. and EGFL did not show a in the of the cells when with the medium and GST (Fig. and The effects of GST fusion proteins on NSCs proliferation in were the as on not results that the FN6-8 domain of TN-R the proliferation of NSCs. TN-R EGFL and FN6-8 NSC EGFL and FN6-8 influence the differentiation of NSCs. cell of NSCs were with and maintained in DMEM/F-12 medium with and fetal calf for days in the of soluble with as a control (Fig. Cells were then and to to III and GFAP, to neurons and astrocytes, In the of EGFL the of cells was increased by a factor of from to when with and (Fig. FN6-8 decreased the of cells from to when with the (Fig. of NSCs into cells was decreased from to of cells (Fig. In the of FN6-8 differentiation into cells was increased to of (Fig. that EGFL NSCs differentiation into neurons at the of astrocytes, whereas FN6-8 NSC differentiation into astrocytes at the of neurons. We EGFL and FN6-8 influence the differentiation of NSCs into oligodendrocytes. cell of NSCs were with and in DMEM/F-12 medium with and fetal calf in the of control and GST, EGFL, and FN6-8 for when cells were and to to and to oligodendrocyte cells and (Fig. EGFL increased the of cells from to in the control to (Fig. whereas decreased the of cells from to to (Fig. FN6-8 decreased the of cells the to and reduced the of cells to the as by EGFL (Fig. that EGFL the existence of NSCs in the oligodendrocyte than the The results show a for FN6-8 to a of cells in the oligodendrocyte but less so at the of the than with We that FN6-8 the differentiation of NSCs into the oligodendrocyte (Fig. The effects of GST fusion proteins on NSCs differentiation were the with that of GST fusion proteins on not and further the effect of EGFL on the differentiation of we of the cell when in with fetal calf (Fig. but when maintained in medium with fetal calf cells are induced to differentiate (Fig. as Brain Res. Dev. Brain Res. 2005; 21: Scopus Google Scholar). EGFL differentiation of these cells into EGFL was to the medium when was from the fetal calf to the fetal days in the of soluble EGFL the expression of was by (Fig. In the of EGFL, expression was reduced when with the control and The expression in the of EGFL in fetal calf was to the of expression in fetal calf (Fig. the that EGFL differentiation of cells into oligodendrocytes. β 1 with EGFL and investigate the effects with EGFL and FN6-8 on proliferation and differentiation were mediated by β 1 the receptor for TN-R R. M. T. P. Eur. J. Neurosci. 1999; 11: PubMed Scopus Google Scholar, P. R. Schachner M. J. Cell 1994; PubMed Google Scholar), we the expression of β 1 integrin by NSCs Neurospheres with and β 1 integrin antibody expression of β 1 integrin (Fig. experiments β 1 integrin on of adult rat of β 1 integrin with TN-R (Fig. experiments with or GST that both EGFL and FN6-8 with β 1 integrin (Fig. FN6-8 of NSCs via β 1 then β 1 integrin mediates the inhibition of NSC proliferation by cell of NSCs were seeded with and maintained in DMEM/F-12 medium with B27, and EGF in the of FN6-8 (Fig. under the as shown for In the of FN6-8 to β 1 integrin NSC proliferation when with the control (Fig. In the of to β 1 the inhibition of proliferation of NSCs induced by FN6-8 was to control (Fig. that FN6-8 the proliferation of NSCs via β 1 integrin. EGFL and FN6-8 NSC via β 1 investigated 1 integrin mediates the effects of EGFL and FN6-8 on NSC differentiation β 1 integrin (Fig. β 1 were to the of NSC as described in the to were with to III and astrocytes with to (Fig. The of neurons that was increased by EGFL in the of to β 1 integrin was reduced when β 1 integrin were in the of EGFL (Fig. the of differentiation of NSCs into cells in the of FN6-8 was to control in the of to β 1 integrin (Fig. the of differentiation into cells by EGFL and of differentiation into astrocytes by FN6-8 was in the of to β 1 integrin (Fig. The effects of EGFL and FN6-8 on the differentiation of NSCs into oligodendrocyte cells and oligodendrocytes were by to β 1 integrin (Fig. that effects induced by EGFL and FN6-8 with regard to differentiation into neurons, astrocytes, and oligodendrocytes are mediated by β 1 domains EGFL and FN6-8 affect differentiation of NSCs into oligodendrocytes integrin. show the differentiation pattern of NSCs as in the to oligodendrocytes are with to oligodendrocytes are with to and are with of cells; and cells of cells are are shown as β 1 integrin antibody In the we have the the functional influence of TN-R on neural stem cell differentiation into different cell with a on the major domains of TN-R, the EGFL and the TN-R has been in multiple in the central nervous in neural development in of neural precursor cells of the subventricular zone and rostral migratory stream to in radial migration to the olfactory by capacity as F.S. Jones P.L. Dev. Dyn. 2000; 218: 235-259Crossref PubMed Scopus (557) Google Scholar, A. Chevigny A. Schachner M. Lledo P.M. Nat. Neurosci. 2004; 7: 347-356Crossref PubMed Scopus (191) Google Scholar, E. Halilagic A. Faissner A. Ffrench-Constant C. Development. 2004; 131: 3423-3432Crossref PubMed Scopus (258) Google Scholar). TN-R is in a that be to capacity to to by to J. Schachner M. U. S. A. PubMed Scopus Google Scholar, A. G. G. J. R. Schachner M. Dev. PubMed Scopus Google Scholar). TN-R neurite in a in when as a uniform substrate (10Lochter A. Schachner M. J. Neurosci. 1993; 13: 3986-4000Crossref PubMed Google Scholar, Z.C. Taylor J. Montag D. Rougon G. Schachner M. Eur. J. Neurosci. 1996; 8: 766-782Crossref PubMed Scopus (89) Google Scholar), but growth in boundary with a such as M. Taylor J. Bartsch U. P. Dev. 1994; Google Scholar, J. P. Schachner M. J. Neurosci. Res. 1993; PubMed Scopus Google Scholar). TN-R oligodendrocyte and microglial adhesion and (14Liao H. Bu W.Y. Wang T.H. Ahmed S. Xiao Z.C. J. Biol. Chem. 2005; 280: 8316-8323Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar, Taylor J. P. Schachner M. Exp. Neurol. 109: PubMed Scopus Google Scholar). TN-R as an intrinsic factor for oligodendrocyte differentiation and promotes cell adhesion by a P. S. Schachner M. R. J. Neurosci. 1997; 17: PubMed Google Scholar), an that appears with regard to the of TN-R at of where after of the U. P. M. Schachner M. 1993; Scopus Google Scholar, E.S. B. Bartsch U. Eur. J. Neurosci. 1993; PubMed Scopus Google Scholar). The and mainly expressed by neurons, has been described as a receptor for TN-R on neurons (11Xiao Z.C. Taylor J. Montag D. Rougon G. Schachner M. Eur. J. Neurosci. 1996; 8: 766-782Crossref PubMed Scopus (89) Google Scholar, 12Xiao Z.C. Hillenbrand R. Schachenr M. Thermes S. Rougon G. Gomez S. J. Neurosci. Res. 1997; 49: 698-709Crossref PubMed Scopus (18) Google Scholar, P. G. C. Schachner M. Neuron. 1993; Full Text PDF PubMed Scopus Google Scholar). TN-R with that are in of interneurons G. J. Schmidt S. B. R. Schachner M. J. Comp. Neurol. 2000; PubMed Scopus Google Scholar). The of these different and for TN-R in functional properties has, however, remained Furthermore, the as to domains of this multifunctional molecule are in distinct functions and are the for these domains are not We have investigated of TN-R with regard to the differentiation of NSCs in by on the functions of the major domains of this EGFL and FN6-8, have been shown to be and acting domains (11Xiao Z.C. Taylor J. Montag D. Rougon G. Schachner M. Eur. J. Neurosci. 1996; 8: 766-782Crossref PubMed Scopus (89) Google Scholar, 12Xiao Z.C. Hillenbrand R. Schachenr M. Thermes S. Rougon G. Gomez S. J. Neurosci. Res. 1997; 49: 698-709Crossref PubMed Scopus (18) Google Scholar, 14Liao H. Bu W.Y. Wang T.H. Ahmed S. Xiao Z.C. J. Biol. Chem. 2005; 280: 8316-8323Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar, 28Lochter A. Vaughan L. Kaplony A. Prochiantz A. Schachner M. Faissner A. J. Cell Biol. 1991; 113: 1159-1171Crossref PubMed Scopus (249) Google Scholar). The domains affect the functional of NSCs in distinct proliferation is reduced by FN6-8, whereas differentiation into neurons is enhanced and reduced by FN6-8 at the of differentiation into astrocytes in a and the of differentiation into neurons to a in differentiation into FN6-8 differentiation into neurons, but differentiation into effects of EGFL and FN6-8 were in of cells at the of cells in the of EGFL, being by stem cells to TN-R as a molecule differentiation of precursor cells into neurons as in a in the adult mouse G. J. M. Schachner M. C. Stem 26: PubMed Scopus Google Scholar). these functions to be mediated by β 1 is well expressed by NSCs. EGFL and FN6-8 with β 1 integrin on cell types, neurons, astrocytes, and oligodendrocytes. Furthermore, proliferation of NSCs by FN6-8 is mediated by β 1 integrin. The β 1 integrin such effects on NSCs. We that different with β 1 be is that the integrin with distinct cell surface in the of for such are the adhesion molecule the of and The in such receptor the and differentiation of NSCs. The such in a that is in expression this is is and we that in cell in the that the to different such as EGFL and FN6-8 on the of the receptor at the cell surface of the The of this and a better of the mechanisms of a in stem cell behavior in of the central nervous system and further for cells for in the of central nervous system We Dr. Zhi-Cheng Xiao for plasmids and with