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.

scholarly journals Role of glycosylation in transport and enzymic activity of neutral endopeptidase-24.11

1994 ◽  
Vol 302 (2) ◽  
pp. 451-454 ◽  
Author(s):  
M H Lafrance ◽  
C Vézina ◽  
Q Wang ◽  
G Boileau ◽  
P Crine ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Cell Surface ◽  
Intracellular Transport ◽  
Neutral Endopeptidase ◽  
Soluble Form ◽  
Cell Extracts ◽  
Glycosylation Sites ◽  
Sugar Addition ◽  
Membrane Bound

Neutral endopeptidase (NEP, EC 3.4.24.11) is a major ectoenzyme of the brush-border membrane. The ectodomain of NEP contains five putative N-glycosylation sites. In order to determine the role of the addition of sugar moieties on the activity and intracellular transport of NEP, we have used site-directed mutagenesis to remove all or some of the five potential sites of sugar addition in membrane-bound and secreted forms of the enzyme. Expression of NEP glycosylation mutants in COS-1 cells showed that all five sites are used for sugar addition. Immunoblotting of NEP in COS-1 cell extracts or culture media indicated that total expression of normal membrane-bound NEP was not affected by mutations at glycosylation sites, whereas this expression level appeared to be strictly dependent on the number of glycosylation sites retained on the soluble form. The transport to the cell surface was also reduced by decreased glycosylation, but again the phenomenon appeared more drastic in the case of the soluble form than for the membrane-bound enzyme. Enzyme activity was decreased by deglycosylation. However, the presence of either of two crucial sites (sites 1 and 5; numbered from the N-terminus of the protein) was sufficient to recover close-to-normal enzymic activities. Transport to the cell surface and enzyme activity of NEP are thus both dependent on sugar residues, probably through different conformational constraints. These constraints seem to be local for enzyme activity but more global for transport to the cell surface.

scholarly journals Characterization of neutral endopeptidase 24.11 in dog glomeruli

1993 ◽  
Vol 291 (3) ◽  
pp. 773-779 ◽  
Author(s):  
C Landry ◽  
P Santagata ◽  
W Bawab ◽  
M C Fournié-Zaluski ◽  
B P Roques ◽  
...  
Keyword(s):  
Cell Surface ◽  
Brush Border ◽  
Neutral Endopeptidase ◽  
Glycosylation Pattern ◽  
Electrophoretic Mobilities ◽  
Mammalian Tissues ◽  
Dog Kidney ◽  
A Cell ◽  
Membrane Bound ◽  
Triton X

Neutral endopeptidase (NEP; also known as neprilysin and enkephalinase; EC 3.4.24.11) is a cell-surface metallopeptidase that is present in many mammalian tissues. It is particularly abundant on the brush-border membranes of the kidney proximal tubule. In this paper, the presence of NEP in purified glomeruli from dog kidney was assessed by measuring phosphoramidon- and thiorphan-sensitive [D-Ala2,Leu5]enkephalin-degrading activity. Using this assay, the Km and kcat. of the glomerular enzyme were found to be identical to those of the tubular enzyme. By Western blotting the apparent M(r) of the glomerular enzyme was found to be 104,000, compared with 94,000 for the tubular enzyme. This might be due to a different glycosylation pattern, since endoglycosidase F treatment of NEP obtained from both tissues yielded deglycosylated enzymes with similar electrophoretic mobilities. The glomerular enzyme also appears to be membrane-bound, since it was retained in the detergent-rich phase after phase separation with Triton X-114. Autoradiography experiments performed with RB104, a new highly selective and potent NEP inhibitor, showed that NEP was expressed in both glomeruli and proximal tubules. The presence in glomeruli of NEP and some other brush-border peptidases (dipeptidyl-dipeptidase IV, aminopeptidase N and angiotensin I-converting enzyme) suggests that cell-surface peptidases might play an important role as regulators of plasma-derived peptides in this part of the nephron.

scholarly journals The purification and specificity of a neutral endopeptidase from rabbit kidney brush border

1974 ◽  
Vol 137 (3) ◽  
pp. 477-488 ◽  
Author(s):  
M. A. Kerr ◽  
A. J. Kenny
Keyword(s):  
Brush Border ◽  
Proteolytic Enzymes ◽  
Deae Cellulose ◽  
Neutral Endopeptidase ◽  
Disc Electrophoresis ◽  
Soluble Form ◽  
Rabbit Kidney ◽  
Peptidase Activity ◽  
Prolonged Incubation ◽  
Microsomal Pellet

1. A neutral peptidase, previously shown to be located in the brush border of the proximal tubule, and assayed by its ability to hydrolyse [125I]iodoinsulin B chain was purified from rabbit kidney. 2. The starting material for the purification was a microsomal pellet prepared from a homogenate of cortical tissue. The membrane-bound enzymes were solubilized by treatment with toluene and trypsin. About half the neutral peptidase activity was released by this treatment in a form that no longer sedimented with the microsomal pellet and which penetrated polyacrylamide gels when subjected to disc electrophoresis. Other treatments with detergents or proteolytic enzymes either inactivated the peptidase or failed to convert it into a genuinely soluble form. 3. Chromatography with successive columns of Sephadex G-200, DEAE-cellulose and hydroxyl-apatite yielded an enzyme that was free of other brush-border peptidase activities and which was homogeneous on disc electrophoresis and ultracentrifugation. 4. The purified enzyme attacked [125I]iodoglucagon at a rate comparable with that for [125I]iodoinsulin B chain. It did not appear to attack proteins (insulin, albumin and casein) that had been similarly iodinated. 5. Unlabelled insulin B chain and unlabelled glucagon were substantially hydrolysed by the endopeptidase, whereas insulin and albumin released only trivial amounts of ninhydrin-reacting material. The resistance of insulin to attack by endopeptidase, even after prolonged incubation, was confirmed by biological and immunoassay. 6. The specificity of the peptidase was determined by analysis of the products after incubating unlabelled insulin B chain, and some oligopeptide substrates, including pentagastrin, with the enzyme. All of the bonds readily cleaved were those involving the α-amino group of hydrophobic residues, i.e. x-Leu-, x-Val-, x-Tyr-, x-Phe- and x-Met-, provided that the residues were not C-terminal. 7. The enzyme showed only endopeptidase activity. Substrates suitable for aminopeptidases, carboxypeptidases or esterases were not attacked.

Immunogold labelling of neutral endopeptidase 24.11 (enkephalinase), on human neutrophils and neutrophil cytoplasts

1989 ◽  
Vol 47 ◽  
pp. 920-921
Author(s):  
V. Kriho ◽  
B. Wagner ◽  
E.G. Erdos ◽  
R.P. Becker
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Cell Surface ◽  
Plasma Membranes ◽  
Intact Cell ◽  
Neutral Endopeptidase ◽  
Immunogold Labelling ◽  
Human Neutrophils ◽  
Endopeptidase 24.11 ◽  
Cell Surface Structure

We have documented the presence of neutral endopeptidase 24.11 (NEP), on the surface of human neutrophils (PMN) and PMN cytoplasts. Cytoplasts are whole cell preparations which contain cytomatrix, but lack internal membranes and organelles ,such as nuclei and lysosomal granules. These structures have been extracted mechanically, leaving the plasma membrane “outside-out” topology intact. Cytoplasts are very useful in correlative studies of cell surface structure and function. Biochemically, the membrane component of cytoplasts is predominantly plasma membrane; structurally, chemical activity may be localized to domains of the intact cell surface. NEP is a membrane-bound metalloendopeptidase present in human PMN' s. We have marked NEP on the plasma membranes of PMNs and PMN cytoplasts via pre-embedding iramunocytochemistry. We used scanning electron microscopy (SEM) with backscattered electron imaging (BEI) to visualize Au labelled anti-NEP on the surface of a large number of cells. Transmission electron microscopy (TEM) was used to confirm the presence of the enzyme on PMN's and PMN cytoplasts.Suspensions of PMN or PMN cytoplasts (2 x 106 cells/ml) were fixed for 8 min at room temp. in 0.25% glutaraldehyde in phosphate buffered saline (PBS) pH 7.2 rinsed in PBS, treated with 0.1% glycine in PBS for 10 rain and then incubated for 15 min in 5% normal goat serum (NGS) in 0.1% bovine serum albumin dissolved in PBS (BSA/PBS). Following this step, cells were incubated for 20 min in anti- NEP antibody, rinsed in BSA/PBS, incubated in goat anti-rabbit IgG coupled to 15nm colloidal Au particles (GARG15) for 1 h and again rinsed in PBS. Postfixation for 30 min in 2.5% glutaraldehyde and PBS rinsing followed. For SEM a drop of cell suspension was put on a polylysine- treated Formvar-carbon-coated Au grid and cells were allowed to settle and attach for 30 min. The grid was rinsed in water, dehydrated and critical point dried. Cells were coated with carbon before viewing by SEM. For TEM, following immunolabelling, cells were post-fixed in OsO4, rinsed, dehydrated and embedded in Epon for sectioning.

CD10 (CALLA)/neutral endopeptidase 24.11 modulates inflammatory peptide- induced changes in neutrophil morphology, migration, and adhesion proteins and is itself regulated by neutrophil activation

Blood ◽  
1991 ◽  
Vol 78 (7) ◽  
pp. 1834-1841 ◽  
Author(s):  
MA Shipp ◽  
GB Stefano ◽  
SN Switzer ◽  
JD Griffin ◽  
EL Reinherz
Keyword(s):  
Substance P ◽  
Cell Surface ◽  
Enzymatic Activity ◽  
Inflammatory Responses ◽  
Lymphoblastic Leukemia ◽  
Neutral Endopeptidase ◽  
Biologically Active ◽  
Zinc Metalloprotease ◽  
Endopeptidase 24.11 ◽  
Induced Changes

Abstract The common acute lymphoblastic leukemia antigen (CALLA, CD10), which is expressed on early lymphoid progenitors and neutrophils, is the zinc metalloprotease, neutral endopeptidase 24.11 (NEP, “enkephalinase”). The CD10 cell surface enzyme is known to hydrolyze a variety of biologically active peptides including met-enkephalin, formyl-met-leu- phe (f-MLP), and substance P. These three CD10/NEP substrates induce the migration and aggregation of neutrophils, suggesting that each of the peptides can function as a mediator of neutrophil inflammatory responses. Recently, inhibition of CD10/NEP was found to reduce the concentration of metenkephalin needed to activate human and invertebrate granulocytes by several orders of magnitude. Herein we show that f-MLP and substance P induce rapid changes in neutrophil morphology, migration, and adhesion molecule expression, including upregulation of Mo1 (CD11b/CD18) and shedding of LAM-1 (also known as LECAM-1, Leu8, or TQ-1, the human homologue of murine gp100MEL14). Importantly, these coordinated changes are potentiated by inhibition of cell surface CD10/NEP enzymatic activity. Neutrophil cell surface CD10/NEP enzymatic activity is also shown to be regulated by the activation state of the cell during the time period in which the enzyme has its most pronounced effects. These results suggest that in neutrophils, CD10/NEP functions to control responsiveness to multiple inflammatory peptides.

scholarly journals Amino acid sequence of rabbit kidney neutral endopeptidase 24.11 (enkephalinase) deduced from a complementary DNA.

1987 ◽  
Vol 6 (5) ◽  
pp. 1317-1322 ◽  
Author(s):  
A. Devault ◽  
C. Lazure ◽  
C. Nault ◽  
H. Le Moual ◽  
N. G. Seidah ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Neutral Endopeptidase ◽  
Rabbit Kidney ◽  
Complementary Dna ◽  
Endopeptidase 24.11

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.

Distribution of, and a putative role for, the cell-surface neutral metallo-endopeptidases during mammalian craniofacial development

Development ◽  
1994 ◽  
Vol 120 (11) ◽  
pp. 3213-3226 ◽  
Author(s):  
B. Spencer-Dene ◽  
P. Thorogood ◽  
S. Nair ◽  
A.J. Kenny ◽  
M. Harris ◽  
...  
Keyword(s):  
Embryonic Development ◽  
Cell Surface ◽  
Choroid Plexus ◽  
Neutral Endopeptidase ◽  
Apical Surface ◽  
Endopeptidase 24.11 ◽  
Ependymal Layer ◽  
Enzymes Inhibition ◽  
Wide Range ◽  
Inhibition Studies

Endopeptidase-24.11 (neutral endopeptidase, neprilysin, ‘enkephalinase’, EC 3.4.24.11) and endopeptidase-24.18 (endopeptidase-2, meprin, EC 3.4.24.18) are cell-surface zinc-dependent metallo-endopeptidases able to cleave a variety of bioactive peptides including growth factors. We report the first study of the cellular and tissue distribution of both enzymes and of the mRNA for NEP during embryonic development in the rat. Endopeptidase-24.11 protein was first detected at E10 in the lining of the gut and, at E12, the enzyme was present on the notochord, medial and lateral nasal processes, otocyst, mesonephros, heart and neuroepithelium. In contrast, at this time endopeptidase-24.18 was present only on the apical surface of the neuroepithelial cells. By E14 and E16, NEP was also detected in a wide range of craniofacial structures, notably the palatal mesenchyme, the choroid plexus, tongue and perichondrium. The distribution of endopeptidase-24.18 at these stages was restricted to the inner ear, the nasal conchae, and ependymal layer of the brain ventricles and the choroid plexus. Although endopeptidase-24.11 had been detectable in the craniofacial vasculature at E12 and E14, this was no longer apparent at E16. Significantly, the distribution of endopeptidase-24.11 mRNA closely matched the immunolocalization of the protein at all stages investigated. In order to explore the functional role of these enzymes, inhibition studies were carried out using two selective inhibitors of endopeptidase-24.11, phosphoramidon and thiorphan. E9.5 and E10.5 embryos exposed to either inhibitor displayed a characteristic, asymmetric abnormality consisting of a spherical swelling, possibly associated with a haematoma, predominantly on the left side of the prosencephalon, and the severity of this defect appeared to be a dose-dependent phenomenon. This study suggests that these enzymes play previously unrecognized roles during mammalian embryonic development.

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