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Enzyme
Compound
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Query: EC:2.7.10.1 (
ERK
)
95,504
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Neutral endopeptidase (
NEP
; EC. 3.4.24.11) is a type 2 cell surface metalloprotease known by a variety of eponyms, including enkephalinase, common acute lymphoblastic leukemia antigen, and
CD10
. Identified substrates are largely neural or humoral oligopeptide agonists, and the enzyme functions to terminate signaling by degrading the ligand, analogously to acetylcholine/acetylcholinesterase. Targeted disruption of the
NEP
locus in mice results in enhanced lethality to endotoxin shock with a pronounced gene dosage effect. The site(s) of action appears downstream from release of tumor necrosis factor and interleukin-1 since
NEP
-deficient animals demonstrate increased sensitivity to these mediators as well. This unexpected finding indicates an important protective role for
NEP
in septic shock.
...
PMID:Neutral endopeptidase modulation of septic shock. 776 13
Inter- and intralobular mammary fibroblasts have been separated from normal human breast tissue and cultured to study the differential expression of ectoenzymes present within the stroma of the normal gland and associated with breast cancers. Specific ectoenzymes were identified by indirect immunofluorescence and quantified by flow cytometry and semi-quantitative PCR. A consistent difference was noted between the two fibroblast sub-populations at early passage in respect of dipeptidyl peptidase IV (DPP IV) and aminopeptidase N (APN) expression. Early passage intralobular fibroblasts were positive for APN but negative for DPP IV, as seen in the intact tissue. However, with continued sub-culture they gradually began to express DPP IV, until at later passages they became indistinguishable from the interlobular fibroblasts, which were APN and DPP IV-positive at all stages in culture, as they are in intact tissue. Neutral endopeptidase (
NEP
/
CALLA
/
CD10
) is not expressed by normal adult breast fibroblasts but is found in the stroma associated with over 60% of breast cancers. It was up-regulated in vitro on both inter- and intralobular fibroblasts, with final levels that were significantly (< 14 times) higher on the former in all pairs of preparations from individual donors analysed. This difference persisted with continued passage, and levels of the ectoenzyme and its messenger RNA were further up-regulated by hydrocortisone in both populations. These results demonstrate that phenotypically distinct cultures of human mammary fibroblast sub-populations can be used to study the regulation of these stromal ectoenzymes.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Ectoenzyme regulation by phenotypically distinct fibroblast sub-populations isolated from the human mammary gland. 787 58
Bone marrow (BM) stromal cells express
CD10
(cALLA), a surface antigen now known to be a neutral endopeptidase (
NEP
-24.11). The function of
CD10
in BM stroma is unknown, although purified
NEP
-24.11 is known to degrade different substrates including interleukin 1 beta (IL-1 beta). We have therefore employed a
CD10
-positive BM stromal cell line (L2AK) which proliferates in response to IL-1 beta to test the hypothesis that degradation of this cytokine is one of the functions of stromal
CD10
. We first showed that [3H]thymidine incorporation by L2AK cells is enhanced by IL-1 beta in a clear dose-dependent manner. Addition of the
CD10
inhibitor, phosphoramidon, together with IL-1 beta resulted in a left shift in the dose-response curve which corresponded to a 10-fold potentiation of the IL-1 beta effect. These results indicate that
CD10
on bone marrow stromal cells can degrade IL-1 beta and therefore provide a local control of the effects of this, and possibly other, growth factor(s).
...
PMID:A function of CD10 on bone marrow stroma. 799 15
The expression of bombesin-like peptides (BLPs) by pulmonary neuroendocrine cells is transiently upregulated during lung development. A functional role for BLPs is supported by their ability to stimulate lung growth and maturation both in vitro and in vivo during the late stages of lung development. In addition, the cell membrane-associated enzyme
CD10
/neutral endopeptidase 24.11 (
CD10
/
NEP
), which inactivates BLPs and other regulatory peptides, is also expressed by developing lungs and modulates the stimulatory effects of BLPs on lung growth and maturation. We hypothesized that, in addition to expressing BLPs and
CD10
/
NEP
, embryonic lungs must express BLP receptors, and that BLPs may also regulate processes that occur during early lung development such as branching morphogenesis. Using reverse transcriptase-polymerase chain reaction and oligonucleotide primers designed for amplifying a BLP receptor originally isolated from Swiss 3T3 mouse fibroblasts, we found that embryonic mouse lungs express a similar BLP receptor mRNA during the pseudoglandular stage of lung development when branching morphogenesis take place. Subsequently, we evaluated the effects of ligands for this BLP receptor using embryonic mouse lungs in an in vitro model of lung branching morphogenesis. We found that, in comparison with control lungs, treatment with bombesin (1 to 100 nM) resulted in a modest increase in clefts or branching points. In contrast, embryonic mouse lungs treated with the BLP analog [Leu13-psi(CH2NH)Leu14]bombesin (1 microM), which also binds to this BLP receptor but has predominantly antagonistic effects, demonstrated fewer branching points.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Regulation of lung branching morphogenesis by bombesin-like peptides and neutral endopeptidase. 800 40
Neutral endopeptidase 24.11 (
NEP
/
CALLA
/
CD10
), an enzyme expressed on early lymphoid progenitors, neutrophils, and various other cell types, inactivates many biologically active peptides, including the bacterial chemotactic peptide N-formylmethionyl-leucyl-phenylalanine (fMLP). Inhibition of
CD10
/
NEP
on the surface of human neutrophils (PMNs) in vitro inhibits migration toward this chemotaxin, suggesting that enzymatic inactivation by
NEP
regulates the neutrophil response to fMLP. Because PMNs in inflammatory sites are exposed to various cytokines, we evaluated the effects of selected cytokines on
CD10
/
NEP
activity in vitro. Of five cytokines tested--interleukin-1 (IL-1), IL-6, and IL-8, granulocyte colony-stimulating factor, and granulocyte-macrophage colony-stimulating factor (GM-CSF)--GM-CSF provided the most consistent increase in surface
NEP
activity. Low concentrations (10(-9)-10(-7) M) of GM-CSF increased
NEP
activity in a time- and concentration-dependent manner to more than 225% that of control (phosphate-buffered saline-treated) cells. Cytofluorometry of cells stained with a fluorescent antibody to
CD10
indicated that GM-CSF increased expression of surface
CD10
/
NEP
antigen in a similar manner. The effect of GM-CSF on
NEP
activity was enhanced still further by simultaneous exposure to IL-1, suggesting that combinations of cytokines may direct and regulate the neutrophil response within an inflammatory site. Rapid upregulation of
CD10
/
NEP
underscores the importance of this enzyme for control of peptide mediators of inflammation.
...
PMID:Up-regulation of neutral endopeptidase (CALLA) in human neutrophils by granulocyte-macrophage colony-stimulating factor. 831 51
Bombesin-like peptides (BLPs) are mitogens for bronchial epithelial cells and small cell lung carcinomas, and increase fetal lung growth and maturation in utero and in organ cultures. BLPs are hydrolyzed by the enzyme
CD10
/neutral endopeptidase 24.11 (
CD10
/
NEP
) which is expressed in bronchial epithelium and functions to inhibit BLP-mediated growth of small cell lung carcinomas. To determine whether
CD10
/
NEP
regulates peptide-mediated lung development, we administered a specific
CD10
/
NEP
inhibitor, SCH32615, to fetal mice in utero from gestational days e15-17. Fetal lung tissues were evaluated on e18 for: (a) growth using [3H]thymidine incorporation into nuclear DNA; and (b) maturation using: [3H]-choline incorporation into surfactant phospholipids, electron microscopy for type II pneumocytes, and Northern blot analyses for surfactant apoproteins A, B, and C. Inhibition of
CD10
/
NEP
stimulated [3H]thymidine incorporation into DNA (70% above baseline, P < 0.005), [3H]choline incorporation into surfactant phospholipids (38% above baseline, P < 0.005), increased numbers of type II pneumocytes (36% above baseline, P = 0.07), and fivefold higher surfactant protein A transcripts (P < 0.05).
CD10
/
NEP
-mediated effects were completely blocked by the specific bombesin receptor antagonist, [D-Phe12, Leu14]bombesin. These observations suggest that
CD10
/
NEP
regulates fetal lung growth and maturation mediated by endogenous BLPs.
...
PMID:CD10/neutral endopeptidase 24.11 regulates fetal lung growth and maturation in utero by potentiating endogenous bombesin-like peptides. 848 58
Neutral endopeptidase (
NEP
; also known as EC 3.4.24.11,
CALLA
) is a widely distributed membrane-bound enzyme that hydrolyzes many biologically important endogenous peptides. To evaluate the influence of glucocorticoids on airway epithelial cell
NEP
expression, we used the human airway epithelial cell line Calu-1. Cells, grown to confluency in Dulbecco's modified Eagle medium with 10% fetal bovine serum and penicillin-streptomycin, were incubated with different concentrations of dexamethasone or vehicle alone in the presence or absence of actinomycin D or cycloheximide for planned times.
NEP
activity was assayed at the end of treatment employing reverse-phase, high-pressure liquid chromatography. In some experiments, changes in
NEP
-specific mRNAs in the presence or absence of dexamethasone and/or the inhibitors were also evaluated by Northern blot analysis. We found that dexamethasone increased Calu-1
NEP
activity in a dose- and time-dependent manner. Northern blot analysis indicated that
NEP
-specific mRNAs were also increased by dexamethasone. Furthermore, neither actinomycin D nor cycloheximide inhibited the increases in
NEP
activity and
NEP
-specific mRNAs caused by dexamethasone stimulation. We speculate, therefore, that dexamethasone increases
NEP
expression of these airway epithelial cells by enhancing transcription and new protein synthesis.
...
PMID:Dexamethasone increases airway epithelial cell neutral endopeptidase by enhancing transcription and new protein synthesis. 850 56
The cell-surface zinc metalloproteinase
CD10
/neutral endopeptidase 24.11 (
CD10
/
NEP
) hydrolyzes a variety of peptide substrates and regulates related peptide-mediated cellular responses. Because the enzyme functions as part of a peptide regulatory loop, the fact that
CD10
/
NEP
itself varies with cellular activation is of considerable interest. In hematopoietic and nonhematopoietic cell types, the levels of
CD10
/
NEP
protein and enzymatic activity correlate with transcript abundance. For these reasons, we investigated the regulation of
CD10
/
NEP
transcripts in the phorbol ester-treated acute lymphoblastic leukemia cell line, REH. When REH cells are treated with phorbol myristate acetate (PMA),
CD10
/
NEP
transcripts rapidly decrease in a labile protein-dependent manner. PMA has a modest effect on
CD10
/
NEP
transcription and significantly reduces
CD10
/
NEP
mRNA stability. Of note, the predicted secondary structure of the
CD10
/
NEP
3' untranslated region includes several stem loop structures that may affect the stability of
CD10
/
NEP
transcripts.
...
PMID:Phorbol ester-mediated regulation of CD10/neutral endopeptidase transcripts in acute lymphoblastic leukemias. 853 91
Neutral endopeptidase (
NEP
; EC 3.4.24.11) is a type-2 cell-surface metalloproteinase known by a variety of eponyms, including enkephalinase, common acute lymphoblastic leukemia antigen (CALLA), and
CD10
. Identified substrates are largely neural or humoral oligopeptide agonists, and the enzyme functions to terminate signaling by degrading the ligand, analogous to the acetylcholine/acetylcholinesterase system. Targeted disruption of the
NEP
locus in mice results in enhanced lethality to endotoxin shock with a pronounced gene-dosage effect. The site(s) of action appears downstream from release of TNF and IL-1, as
NEP
-deficient animals demonstrate increased sensitivity to these mediators as well. This unexpected finding indicates an important protective role for
NEP
in septic shock.
...
PMID:Neutral endopeptidase modulates septic shock. 860 28
Neutral endopeptidase (
NEP
;
CALLA
,
CD10
, EC 3.4.24.11) is a cell surface endopeptidase that hydrolyses bioactive peptides, including the bombesin-like peptides, as well as other neuropeptides. Bombesin-like peptides and other neuropeptides are autocrine growth factors for both small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Low expression of
NEP
has been reported in SCLC and NSCLC cell lines.
NEP
inhibition has been shown to increase proliferation in one cell line. To date,
NEP
expression has not been quantitatively evaluated in normal adult lung, SCLC or NSCLC tumors, paired uninvolved lung from the same patient, or in other pulmonary neoplasms such as mesotheliomas and carcinoids. We examined the expression of
NEP
in these tissues and human cell lines using immunohistochemistry, flow cytometry, enzyme activity, ELISA, Western blot, and reverse transcription (RT)-PCR. Uninvolved lung tissue from different individuals displayed considerable variation in
NEP
activity and protein. By immunohistochemistry,
NEP
expression was detectable in alveolar and airway epithelium, fibroblasts of normal lung, and in mesotheliomas, whereas it was undetectable in most SCLC, adenocarcinoma, squamous cell carcinoma, and carcinoid tumors of the lung.
NEP
activity and protein levels were lower in all SCLC and adenocarcinoma tumors when compared to adjacent uninvolved lung, often at levels consistent with expression derived from contaminating stroma.
NEP
expression and activity were reduced or undetectable in most SCLC and lung adenocarcinoma cell lines.
NEP
mRNA by RT-PCR was not expressed or was in low abundance in the majority of lung cancer cell lines. The majority of lung tumors did not express
NEP
by RT-PCR as compared with normal adjacent lung. In addition, recombinant
NEP
abolished, whereas an
NEP
inhibitor potentiated, the calcium flux generated by neuropeptides in some lung cancer cell lines, demonstrating potential physiological significance for low
NEP
expression.
NEP
, therefore, is a signal transduction and possibly a growth modulator for both SCLC and NSCLC, emphasizing the role of neuropeptides in the pathogenesis of the major histological forms of lung cancer.
...
PMID:Neutral endopeptidase: variable expression in human lung, inactivation in lung cancer, and modulation of peptide-induced calcium flux. 863 Oct 21
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