scholarly journals Recombinant neutral endopeptidase-24.11 expressed in mouse neuroblastoma cells is associated with neurite membranes

1990 ◽  
Vol 267 (2) ◽  
pp. 447-452 ◽  
Author(s):  
G Lemay ◽  
M Zollinger ◽  
G Waksman ◽  
B P Roques ◽  
P Crine ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Line ◽  
Neuroblastoma Cell ◽  
Neuroblastoma Cells ◽  
Neutral Endopeptidase ◽  
Rabbit Kidney ◽  
Synaptic Membranes ◽  
Membrane Domains ◽  
Mouse Neuroblastoma ◽  
Endopeptidase 24.11

Neutral endopeptidase-24.11 (EC 3.4.24.11) (NEP) is a transmembrane metallo-endopeptidase that has been shown to be involved in the degradation of several mammalian neuropeptides, including enkephalins. The enzyme has recently been found to be specifically associated with the axonal and synaptic membranes of neurons in the globus pallidus of the pig brain. This result suggests that neurons must possess mechanisms for targeting NEP to particular membrane domains. Study of these mechanisms would greatly benefit from the existence of an established neuron-like cell line capable of expressing and targeting NEP to specific membrane domains. For this reason we have used a retroviral vector containing the cDNA for rabbit kidney NEP to express this enzyme in a mouse neuroblastoma cell line (Neuro2A). Labelling of the cell surface with an antibody coupled to colloidal gold particles and examination of the cells by electron microscopy revealed a non-uniform distribution of NEP at the surface of the cells, the protein being preferentially associated with the membrane of neurites compared with the cell body. This observation suggests that Neuro2A cells possess a mechanism for targeting NEP to specific domains of the plasma membrane. This cell line could thus constitute a good model for studying the mechanisms responsible for targeting this enzyme to specialized regions of the plasma membrane.

scholarly journals Reversible effects of sphingomyelin degradation on cholesterol distribution and metabolism in fibroblasts and transformed neuroblastoma cells

1990 ◽  
Vol 271 (1) ◽  
pp. 121-126 ◽  
Author(s):  
M I Pörn ◽  
J P Slotte
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Cell Line ◽  
Cholesterol Oxidase ◽  
Neuroblastoma Cell ◽  
Control Level ◽  
Neuroblastoma Cells ◽  
Long Term Effects ◽  
Human Lung Fibroblast ◽  
Acat Activity

Plasma-membrane sphingomyelin appears to be one of the major determinants of the preferential allocation of cell cholesterol into the plasma-membrane compartment, since removal of sphingomyelin leads to a dramatic redistribution of cholesterol within the cell [Slotte & Bierman (1988) Biochem. J. 250, 653-658]. In the present study we examined the long-term effects of sphingomyelin degradation on cholesterol redistribution in cells and determined the reversibility of the process. In a human lung fibroblast-cell line, removal of 80% of the sphingomyelin led to a rapid and transient up-regulation (3-fold) of acyl-CoA:cholesterol acyltransferase (ACAT) activity, and also, within 30 h, to the translocation of about 50% of the cell non-esterified cholesterol from a cholesterol oxidase-susceptible compartment (i.e. the cell surface) to oxidase-resistant compartments. At 49 h after the initial sphingomyelin degradation, the cell sphingomyelin level was back to 45% of the control level, and the direction of cell cholesterol flow was toward the cell surface, although the original distribution was not achieved. In a transformed neuroblastoma cell line (SH-SY5Y), the depletion of sphingomyelin led to a similarly rapid and transient up-regulation of ACAT activity, and to the translocation of about 25% of cell-surface cholesterol into internal membranes (within 3 h). The flow of cholesterol back to the cholesterol oxidase-susceptible pool was rapid, and a pretreatment cholesterol distribution was reached within 20-49 h. Also, the resynthesis of sphingomyelin was faster in SH-SY5Y neuroblastoma cells and reached control levels within 24 h. The findings of the present study show that the cellular redistribution of cholesterol, as induced by sphingomyelin degradation, is reversible and suggest that the normalization of cellular cholesterol distribution is linked to the re-synthesis of sphingomyelin.

scholarly journals Modulation of calcium signaling depends on the oligosaccharide of GM1 in Neuro2a mouse neuroblastoma cells

2020 ◽  
Vol 37 (6) ◽  
pp. 713-727
Author(s):  
Giulia Lunghi ◽  
Maria Fazzari ◽  
Erika Di Biase ◽  
Laura Mauri ◽  
Sandro Sonnino ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Calcium Channels ◽  
Calcium Signaling ◽  
Intracellular Calcium ◽  
Calcium Imaging ◽  
Neuroblastoma Cells ◽  
Ganglioside Gm1 ◽  
Mouse Neuroblastoma ◽  
Neuro2a Cells ◽  
Neuronal Functions

AbstractRecently, we demonstrated that the oligosaccharide portion of ganglioside GM1 is responsible, via direct interaction and activation of the TrkA pathway, for the ability of GM1 to promote neuritogenesis and to confer neuroprotection in Neuro2a mouse neuroblastoma cells. Recalling the knowledge that ganglioside GM1 modulates calcium channels activity, thus regulating the cytosolic calcium concentration necessary for neuronal functions, we investigated if the GM1-oligosaccharide would be able to overlap the GM1 properties in the regulation of calcium signaling, excluding a specific role played by the ceramide moiety inserted into the external layer of plasma membrane. We observed, by calcium imaging, that GM1-oligosaccharide administration to undifferentiated Neuro2a cells resulted in an increased calcium influx, which turned out to be mediated by the activation of TrkA receptor. The biochemical analysis demonstrated that PLCγ and PKC activation follows the TrkA stimulation by GM1-oligosaccharide, leading to the opening of calcium channels both on the plasma membrane and on intracellular storages, as confirmed by calcium imaging experiments performed with IP3 receptor inhibitor. Subsequently, we found that neurite elongation in Neuro2a cells was blocked by subtoxic administration of extracellular and intracellular calcium chelators, suggesting that the increase of intracellular calcium is responsible of GM1-oligosaccharide mediated differentiation. These results suggest that GM1-oligosaccharide is responsible for the regulation of calcium signaling and homeostasis at the base of the neuronal functions mediated by plasma membrane GM1.

Clusterin Overexpression is Responsible for the Anti-apoptosis Effect in a Mouse Neuroblastoma Cell Line, B103

2003 ◽  
Vol 58 (1-2) ◽  
pp. 148-152 ◽  
Author(s):  
Kwan-Hee You ◽  
Young-Mi Ji ◽  
O-Yu Kwon
Keyword(s):  
Cell Line ◽  
Functional Role ◽  
Neuroblastoma Cell ◽  
Neuroblastoma Cell Line ◽  
Apoptotic Index ◽  
Mouse Neuroblastoma Cell ◽  
Mouse Neuroblastoma ◽  
Apoptosis Inhibition ◽  
Clusterin Expression

The functional role of clusterin in apoptosis was examined using flow cytometry. Clusterin cDNA was transfected into the mouse neuroblastoma cell line, B103, in order to determine if clusterin overexpression inhibits apoptosis. The increased clusterin expression level in the B103 cells tended to suppress the apoptotic index. This suggests an association of clusterin gene expression with apoptosis inhibition. These results support the conclusion that clusterin expression in B103 cells has an antiapoptotic influence

TTX-Sensitive and -Resistant Na+ Currents, and mRNA for the TTX-Resistant rH1 Channel, Are Expressed in B104 Neuroblastoma Cells

1997 ◽  
Vol 77 (1) ◽  
pp. 236-246 ◽  
Author(s):  
Xiang Q. Gu ◽  
Sulayman Dib-Hajj ◽  
Marco A. Rizzo ◽  
Stephen G. Waxman
Keyword(s):  
Steady State ◽  
Cell Line ◽  
Neuroblastoma Cell ◽  
Neuroblastoma Cells ◽  
Neuroblastoma Cell Line ◽  
Membrane Excitability ◽  
Rt Pcr ◽  
Α Subunit ◽  
Time To Peak ◽  
Steady State Inactivation

Gu, Xiang Q., Sulayman Dib-Hajj, Marco A. Rizzo, and Stephen G. Waxman. TTX-sensitive and -resistant Na+ currents, and mRNA for the TTX-resistant rH1 channel, are expressed in B104 neuroblastoma cells. J. Neurophysiol. 77: 236–246, 1997. To examine the molecular basis for membrane excitability in a neuroblastoma cell line, we used whole cell patch-clamp methods and reverse transcription-polymerase chain reaction (RT-PCR) to study Na+ currents and channels in B104 cells. We distinguished Tetrodotoxin (TTX)-sensitive and -resistant Na+ currents and detected the mRNA for the cardiac rH1 channel in B104 cells. Na+ currents could be recorded in 65% of cells. In the absence of TTX, mean peak Na+ current density was 126 ± 19 pA/pF, corresponding to a channel density of 2.7 ± 0.4/μ2 (mean ± SE). Time-to-peak (t-peak), activation (τm), and inactivation time constants (τh) for Na+ currents in B104 cells were 1.0 ± 0.04, 0.4 ± 0.06, and0.9 ± 0.04 ms at −10 mV. The peak conductance-voltage relationship had a V 1/2 of −39.8 ± 1.5 mV. V 1/2 for steady-state inactivation was −81.6 ± 1.5 mV. TTX-sensitive and -resistant components of the Na current had half-maximal inhibitions (IC50), respectively, of 1.2 nM and, minimally, 575.5 nM. The TTX-sensitive and-resistant Na+ currents were kinetically distinct; time-to-peak, τm, and τh for TTX-sensitive currents were shorter than for TTX-resistant currents. Steady-state voltage dependence of the two currents was indistinguishable. The presence of TTX-sensitive and-resistant Na+ currents, which are pharmacologically and kinetically distinct, led us to search for mRNAs known to be associated with TTX-resistant channels, in addition to the α subunit mRNAs, which have previously been shown to be expressed in these cells. Using RT-PCR and restriction enzyme mapping, we were unable to detect αSNS, but detected mRNA for rH1, which is known to encode a TTX-resistant channel, in B104 cells. B104 neuroblastoma cells thus express TTX-sensitive and -resistant Na+ currents. These appear to be encoded by neuronal-type and cardiac Na+ channel mRNAs including the RH1 transcript. This cell line may be useful for studies on the rH1 channel, which is known to be mutated in the long-QT syndrome.

scholarly journals Polarized distribution of neutral endopeptidase 24.11 at the cell surface of cultured human intestinal epithelial Caco-2 cells

1992 ◽  
Vol 288 (3) ◽  
pp. 945-951 ◽  
Author(s):  
F Jalal ◽  
C Jumarie ◽  
W Bawab ◽  
D Corbeil ◽  
C Malo ◽  
...  
Keyword(s):  
Cell Surface ◽  
Brush Border ◽  
Flow Cytometric Analysis ◽  
Neutral Endopeptidase ◽  
Rabbit Kidney ◽  
Human Colon Cancer ◽  
Cell Extracts ◽  
Endopeptidase 24.11 ◽  
Dpp Iv ◽  
Apical Side

The human colon cancer cell line Caco-2 undergoes spontaneous enterocytic differentiation during growth, and expresses a number of brush-border-membrane-associated hydrolases typical of a differentiated phenotype. Among these are alkaline phosphatase, dipeptidyl peptidase IV and sucrase-isomaltase (sucrase, EC 3.2.1.48). Neutral endopeptidase 24.11 [EC 3.4.24.11, neprilysin (NEP)] is another abundant protease of normal enterocytes but its presence in Caco-2 cells has not been fully documented yet. In this paper, we show that Caco-2 cell extracts hydrolyse tritiated [D-Ala2Leu5]enkephalin with a Km of 180 microM, very close to the value obtained for the NEP present in the rabbit kidney (118 microM). Western-blot analysis of brush-border membranes purified from post-confluent cells revealed a protein with an apparent molecular mass of 94000 Da similar to that of the rabbit kidney NEP. The amount of enzyme in cell extracts increased as a function of the age of the culture, indicating that NEP expression is correlated with the degree of cell differentiation as is also the case for sucrase and dipeptidylpeptidase IV (DPP-IV). Binding of a radiolabelled antibody to Caco-2 cell monolayers grown on semi-permeable filters indicated that 95% of NEP molecules present at the cell surface are on the apical side. Immunocytochemical and flow cytometric analysis of intact and permeabilized cells were also used to investigate the presence of NEP and DPP-IV at the surface of Caco-2 cells. Whereas DPP-IV staining appeared to be homogeneous throughout the entire cell population, NEP-related fluorescence exhibited a bimodal distribution which indicates an uneven expression of the protein at the cell surface. Permeabilization of monolayers with saponin before staining restored a labelling pattern for NEP similar to the one obtained for DPP-IV. This suggests that although DPP-IV and NEP follow similar patterns of expression when enzymic activities are measured on whole-cell extracts, targeting of these brush-border proteins to the cell surface appears to be regulated in different ways.

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