Green Tea Seed Isolated Theasaponin E1 Ameliorates AD Promoting Neurotoxic Pathogenesis by Attenuating Aß Peptide Levels in SweAPP N2a Cells.

Alzheimer's disease (AD) is the most frequent type of dementia affecting memory, thinking and behaviour. The major hallmark of the disease is pathological neurodegeneration due to abnormal aggregation of Amyloid beta (Aß) peptides generated by ß- and γ-secretases via amyloidogenic pathway. Purpose of the current study was to evaluate the effects of theasaponin E1 on the inhibition of Aß producing ß-, γ-secretases (BACE1, PS1 and NCT) and acetylcholinesterase and activation of the non-amyloidogenic APP processing α-secretase (ADAM10). Additionally, theasaponin E1 effects on Aß degrading and clearing proteins neprilysin and insulin degrading enzyme (IDE). The effect of theasaponin E1 on these crucial enzymes was investigated by RT-PCR, ELISA, western blotting and fluorometric assays using mouse neuroblastoma cells (SweAPP N2a). theasaponin E1 was extracted and purified from green tea seed extract via HPLC, and N2a cells were treated with different concentrations for 24 h. Gene and protein expression in the cells were measured to determine the effects of activation and/or inhibition of theasaponin E1 on ß- and γ-secretases, neprilysin and IDE. Results demonstrated that theasaponin E1 significantly reduced Aß concentration by activation of the α-secretase and neprilysin. The activities of ß- and γ-secretase were reduced in a dose-dependent manner due to downregulation of BACE1, presenilin, and nicastrin. Similarly, theasaponin E1 significantly reduced the activity of acetylcholinesterase. Overall, from the results it is concluded that green tea seed extracted saponin E1 possess therapeutic significance as a neuroprotective natural product recommended for the treatment of Alzheimer's disease.

A novel pectin from Polygala tenuifolia blocks Aß42 aggregation and production by enhancing insulin-degradation enzyme and neprilysin.

More and more evidences show that pectin polysaccharide may have impact on Aß42, one important molecule implicated in Alzhemer's disease pathology. We speculate special structural motif of pectin might have better bioactivity on Aß42. To address this hypothesis, we reported structure and impact of a novel pectin RP02-1 with the molecular weight of 116.0 kDa from roots of Polygala tenuifolia on Aß42 aggregation and production and the underlying mechanism. Its structure is characterized as a backbone of alternate 1, 2, 4-linked α-Rhap and 1, 4-linked α-GalpA, with branches of terminal (T) -, 1, 3-,1, 4-, 1, 6- and 1, 3, 6-linked ß-Galp, T-, 1, 5- and 1, 3, 5-linked α-Araf substituted at C-4 of 1, 2, 4-linked α-Rhap. Bioactivity study shows that this pectin may significantly block the aggregation of Aß42. We further show that RP02-1 suppresses Aß42 production with no apparent cytotoxicity in both CHO/APPBACE1 and HEK293-APPsw cells. Mechanism study demonstrates that RP02-1 may enhance the expression of insulin-degradation enzyme (IDE) and neprilysin (NEP), which are the main enzymes involved in Aß degradation. These results suggest that RP02-1 may be a candidate leading compound for anti-Alzheimer's disease new drug development by attenuating Aß42 production and inhibiting Aß42 aggregation.

Regulation of Neprilysin Activity and Cognitive Functions in Rats After Prenatal Hypoxia.

The amyloid-degrading enzyme neprilysin (NEP) is one of the therapeutic targets in prevention and treatment of Alzheimer's disease (AD). As we have shown previously NEP expression in rat parietal cortex (Cx) and hippocampus (Hip) decreases with age and is also significantly reduced after prenatal hypoxia. Following the paradigms for enhancement of NEP expression and activity developed in cell culture, we analysed the efficacy of various compounds able to upregulate NEP using our model of prenatal hypoxia in rats. In addition to the previous data demonstrating that valproic acid can upregulate NEP expression both in neuroblastoma cells and in rat Cx and Hip we have further confirmed that caspase inhibitors can also restore NEP expression in rat Cx reduced after prenatal hypoxia. Here we also report that administration of a green tea catechin epigallocatechin-3-gallate (EGCG) to adult rats subjected to prenatal hypoxia increased NEP activity in blood plasma, Cx and Hip as well as improved memory performance in the 8-arm maze and novel object recognition tests. Moreover, EGCG administration led to an increased number of dendritic spines in the hippocampal CA1 area which correlated with memory enhancement. The data obtained allowed us to conclude that the decrease in the activity of the amyloid-degrading enzyme NEP, as well as a reduction in the number of labile interneuronal contacts in the hippocampus, contribute to early cognitive deficits caused by prenatal hypoxia and that there are therapeutic avenues to restore these deficits via NEP activation which could also be used for designing preventive strategies in AD.

Long-term dietary supplementation with the green tea cultivar Sunrouge prevents age-related cognitive decline in the senescence-accelerated mouse Prone8.

A majority of the potential health benefits of green tea, including the potential to prevent cognitive decline, have been attributed to epigallocatechin gallate (EGCG). Sunrouge is a green tea cultivar that contains EGCG and several other bioactive components such as quercetin, myricetin, cyanidin and delphinidin. We compared the effects of Sunrouge and Yabukita, the most popular Japanese green tea cultivar, on cognitive function in the senescence-accelerated mouse Prone8. These mice were fed an experimental diet containing Sunrouge extract (SRE) or Yabukita extract (YBE). SRE feeding significantly prevented cognitive decline, whereas YBE feeding had little effect. Moreover, SRE feeding prevented elevation of the amyloid-ß42 level while improving the gene expression of neprilysin and decreasing beta-site APP-cleaving enzyme 1 in the brain. These preventive effects of SRE against cognitive decline were attributed to the characteristic composition of Sunrouge and strongly suggest that consumption of this cultivar could protect against age-related cognitive decline.

Global Transcriptome Analysis of the Tentacle of the Jellyfish Cyanea capillata Using Deep Sequencing and Expressed Sequence Tags: Insight into the Toxin- and Degenerative Disease-Related Transcripts.

BACKGROUND: Jellyfish contain diverse toxins and other bioactive components. However, large-scale identification of novel toxins and bioactive components from jellyfish has been hampered by the low efficiency of traditional isolation and purification methods. RESULTS: We performed de novo transcriptome sequencing of the tentacle tissue of the jellyfish Cyanea capillata. A total of 51,304,108 reads were obtained and assembled into 50,536 unigenes. Of these, 21,357 unigenes had homologues in public databases, but the remaining unigenes had no significant matches due to the limited sequence information available and species-specific novel sequences. Functional annotation of the unigenes also revealed general gene expression profile characteristics in the tentacle of C. capillata. A primary goal of this study was to identify putative toxin transcripts. As expected, we screened many transcripts encoding proteins similar to several well-known toxin families including phospholipases, metalloproteases, serine proteases and serine protease inhibitors. In addition, some transcripts also resembled molecules with potential toxic activities, including cnidarian CfTX-like toxins with hemolytic activity, plancitoxin-1, venom toxin-like peptide-6, histamine-releasing factor, neprilysin, dipeptidyl peptidase 4, vascular endothelial growth factor A, angiotensin-converting enzyme-like and endothelin-converting enzyme 1-like proteins. Most of these molecules have not been previously reported in jellyfish. Interestingly, we also characterized a number of transcripts with similarities to proteins relevant to several degenerative diseases, including Huntington's, Alzheimer's and Parkinson's diseases. This is the first description of degenerative disease-associated genes in jellyfish. CONCLUSION: We obtained a well-categorized and annotated transcriptome of C. capillata tentacle that will be an important and valuable resource for further understanding of jellyfish at the molecular level and information on the underlying molecular mechanisms of jellyfish stinging. The findings of this study may also be used in comparative studies of gene expression profiling among different jellyfish species.

Inhibition of human neutrophils NEP activity, CD11b/CD18 expression and elastase release by 3,4-dihydroxyphenylethanol-elenolic acid dialdehyde, oleacein.

Polyphenols, such as oleacein (3,4-DHPEA-EDA; 3,4-dihydroxyphenylethanol-elenolic acid dialdehyde), are believed to play a role in the prevention of cardiovascular diseases. Due to an increase of neutrophil mediators in acute myocardial infarction the aim of this study was to establish the effect of oleacein on neutral endopeptidase (NEP) activity and other functions of human neutrophils, such as elastase, MMP-9 and IL-8 production. The effect on CD62L and CD11b/CD18 expression on neutrophils was also determined. Oleacein with a concentration of 100 µM inhibited NEP activity, elastase, MMP-9 and IL-8 release from neutrophils by 77.7 ± 2.7%, 21.3 ± 7.8%, 22.7 ± 4.2% and 25.2 ± 5.6%, respectively. Oleacein with a concentration of 50 µM suppressed CD11b/CD18 expression by 63.6 ± 3.1% and to a lesser extent, increased CD62L expression by 27.3 ± 8.3% on the surface of neutrophils, in comparison with stimulated cells. Oleacein by inhibiting NEP activity, adhesion molecules expression and elastase release might play a role in the protective effects of olive oil against endothelial injuries.

Effect of neoadjuvant chemotherapy on stromal CD10 antigens in breast cancer - a preliminary study.

INTRODUCTION: CD10 is a zinc-dependent peptidase (metalloproteinase). Stromal CD10 expression in breast cancer correlates with poor prognosis, oestrogen receptor negativity and higher grade. CD10 may be a potential target of new cancer therapies as it is involved in cleavage of doxorubicin. AIM: To evaluate the effect of neo-adjuvant anthracycline-based chemotherapy on status of stromal CD10 antigens in breast cancer. MATERIALS AND METHODS: Patients with invasive breast cancer scheduled for anthracycline-based neo-adjuvant chemotherapy were included in the study. Tumor stromal CD10 expression was estimated before and after 3 cycles of chemotherapy, and change in its status was correlated with clinical response to chemotherapy. RESULTS: 16 out of the 29 patients had strong CD10 expression; in these 16 patients, 14 (87.5%) were hormone receptor negative, and 14 (87.5%) had HER-2/neu overexpression. Stromal CD10 expression remained same in 13 out of 29 cases (44.83%) after chemotherapy. There was a change in CD10 expression in the remaining 16 cases (55.17%); in 13 cases (44.83%) it decreased from its pre-chemotherapy status, while its expression increased in 3 cases (10.34%). In cases of complete and partial clinical response, there was no increase in CD10 expression. Where CD10 expression had increased after chemotherapy, there was either a minor response or no response to chemotherapy. In 13 cases where CD10 expression had decreased, 12 cases had a clinical response to chemotherapy. CONCLUSIONS: Strong CD10 expression correlates with hormone receptor negativity and HER-2/neu overexpression. Stromal CD10 expression in breast cancer is not static and changes with neo-adjuvant anthracycline-based chemotherapy. A stable or decrease in CD10 expression correlates with complete or partial clinical response, while an increase in CD10 expression appears to correlate with poor clinical response. A larger series is required to determine the clinical significance of these changes. As stromal CD10 expression and its change with chemotherapy may have a prognostic significance, they should be documented in breast cancer patients before and after chemotherapy.

Zinc inhibits apoptosis and maintains NEP downregulation, induced by ropivacaine, in HaCaT cells.

Zinc (Zn), a cell-protective metal against various toxic compounds, is the key agent for neutral endopeptidase (NEP) functional structure. NEP is a zinc metalloenzyme which degrades endogenous opioids and is expressed in human keratinocytes (HaCaT). Ropivacaine, a widely used opiate local anaesthetic, exerts cell toxic and apoptotic effects against HaCaT cells. The aim of the present study is to investigate whether zinc modulates the effects of ropivacaine on proliferation, viability, apoptosis and NEP expression in HaCaT cells. To investigate the role of ropivacaine in NEP function, HaCaT cells overexpressing NEP were generated via cell transfection with plasmids carrying NEP cDNA. Ropivacaine's anti-proliferative effect was tested by Neubauer's chamber cell counting, and induction of cell death was demonstrated by trypan blue exclusion assay. Apoptosis due to ropivacaine was tested via DNA fragmentation and poly-ADP-ribose-polymerase (PARP) cleavage. NEP and PARP expression was performed by western blot analysis. Results showed that zinc (15 µΜ) inhibited proliferation and cell death induction by ropivacaine (0.5, 1 and 2 mM) (p < 0.05) as well as apoptosis induced by the drug (0.5 and 1 mM) in HaCaT cells. Ropivacaine (1.0, 2.0 and 5.0 mM) downregulated NEP expression in the presence of zinc (15 µΜ) while NEP overexpression enhanced ropivacaine's apoptotic effect. In conclusion, the abilities of zinc to inhibit the toxic and apoptotic effects of ropivacaine, to maintain NEP downregulation induced by the drug and, consequently, to enhance its anaesthetic result suggest that zinc may have a significant role in pain management and tissue protection.

Withania somnifera reverses Alzheimer's disease pathology by enhancing low-density lipoprotein receptor-related protein in liver.

A 30-d course of oral administration of a semipurified extract of the root of Withania somnifera consisting predominantly of withanolides and withanosides reversed behavioral deficits, plaque pathology, accumulation of ß-amyloid peptides (Aß) and oligomers in the brains of middle-aged and old APP/PS1 Alzheimer's disease transgenic mice. It was similarly effective in reversing behavioral deficits and plaque load in APPSwInd mice (line J20). The temporal sequence involved an increase in plasma Aß and a decrease in brain Aß monomer after 7 d, indicating increased transport of Aß from the brain to the periphery. Enhanced expression of low-density lipoprotein receptor-related protein (LRP) in brain microvessels and the Aß-degrading protease neprilysin (NEP) occurred 14-21 d after a substantial decrease in brain Aß levels. However, significant increase in liver LRP and NEP occurred much earlier, at 7 d, and were accompanied by a rise in plasma sLRP, a peripheral sink for brain Aß. In WT mice, the extract induced liver, but not brain, LRP and NEP and decreased plasma and brain Aß, indicating that increase in liver LRP and sLRP occurring independent of Aß concentration could result in clearance of Aß. Selective down-regulation of liver LRP, but not NEP, abrogated the therapeutic effects of the extract. The remarkable therapeutic effect of W. somnifera mediated through up-regulation of liver LRP indicates that targeting the periphery offers a unique mechanism for Aß clearance and reverses the behavioral deficits and pathology seen in Alzheimer's disease models.

A novel system for in vivo neprilysin gene delivery using a syringe electrode.

Existing methods for in vivo gene transfer are generally inefficient and have several technical problems. In the present study we aimed to develop a safe, simple and efficient gene-delivery system for in vivo therapeutic applications. We focused on delivery of a plasmid encoding human neprilysin (hNEP), an enzyme implicated in the degradation of toxic amyloid-beta (Abeta) peptide, with potential application in Alzheimer's disease therapy. We report the development of a syringe electrode device in which DNA is injected via one of the two syringes and DNA uptake is stimulated by application of a brief pulsed square-wave electrical field between the two syringe needles. Using this device, purified plasmid DNA encoding hNEP was injected into hindlimb skeletal muscle of 6-week-old KunMing mice and electrostimulation (50V/cm, 6 pulses, 20ms per pulse) was applied to the syringe needles. hNEP protein was detected in muscle, serum and brain of treated mice by western blotting and ELISA at 7, 14 and 30 days post-transfer. Importantly, hNEP levels following DNA injection alone, but without electrostimulation, were barely above background. Only low levels of muscle damage were detected following DNA injection and electrotransfer. These results demonstrate that DNA delivery by the syringe electrode technique can give rise to efficient long-term expression of the encoded polypeptide, and that the electrotransfer protocol is essential for effective plasmid DNA uptake and expression. This technique provides a safe and efficient non-viral method for in vivo gene delivery with potential applications in both basic research and in gene therapy of neuronal disease.

Autocrine regulation of human sperm motility by tachykinins.

BACKGROUND: We examined the presence and function of tachykinins and the tachykinin-degrading enzymes neprilysin (NEP) and neprilysin-2 (NEP2) in human spermatozoa. METHODS: Freshly ejaculated semen was collected from forty-eight normozoospermic human donors. We analyzed the expression of substance P, neurokinin A, neurokinin B, hemokinin-1, NEP and NEP2 in sperm cells by reverse-transcriptase polymerase chain reaction (RT-PCR), western blot and immunocytochemistry assays and evaluated the effects of the neprilysin and neprilysin-2 inhibitor phosphoramidon on sperm motility in the absence and presence of tachykinin receptor-selective antagonists. Sperm motility was measured using WHO procedures or computer-assisted sperm analysis (CASA). RESULTS: The mRNAs of the genes that encode substance P/neurokinin A (TAC1), neurokinin B (TAC3), hemokinin-1 (TAC4), neprilysin (MME) and neprilysin-2 (MMEL1) were expressed in human sperm. Immunocytochemistry studies revealed that tachykinin and neprilysin proteins were present in spermatozoa and show specific and differential distributions. Phosphoramidon increased sperm progressive motility and its effects were reduced in the presence of the tachykinin receptor antagonists SR140333 (NK1 receptor-selective) and SR48968 (NK2 receptor-selective) but unmodified in the presence of SR142801 (NK3 receptor-selective). CONCLUSION: These data show that tachykinins are present in human spermatozoa and participate in the regulation of sperm motility. Tachykinin activity is regulated, at least in part, by neprilysins.

Immunohistochemical profile and fluorescence in situ hybridization analysis of diffuse large B-cell lymphoma in northern China.

CONTEXT: Gene expression profiling of diffuse large B-cell lymphoma using complementary DNA microarrays has revealed 2 major prognostic groups in Western countries: germinal center B-cell-like and nongerminal center B-cell-like lymphomas. Immunohistochemical analysis using antibodies specific for CD10, BCL6, and MUM1 has been proposed as a surrogate for gene expression profiling. OBJECTIVE: To study the immunohistochemical features of diffuse large B-cell lymphoma cases from northern China because geographic differences for this disease are known to exist. DESIGN: Morphologic, immunohistochemical, and fluorescence in situ hybridization analyses of 63 cases of diffuse large B-cell lymphoma from northern China. RESULTS: There were 38 men and 25 women with a median age of 57 years (range, 12-87 years). CD10 was positive in 19 cases (30%), BCL6 was positive in 22 cases (35%), and MUM1 was positive in 32 cases (51%). Twenty-one (33%) cases were germinal center B-cell-like lymphoma, and 42 (67%) were nongerminal center B-cell-like lymphoma. BCL2 was expressed more often in nongerminal center B-cell-like disease versus germinal center B-cell-like disease (60% versus 24%, P = .01) and in nodal versus extranodal (64% versus 30%, P = .01) cases. Fluorescence in situ hybridization analysis showed BCL6, MYC , and BCL2 rearrangements in 11 of 32 (34%), 8 of 27 (30%), and 11 of 50 (22%) cases, respectively. CONCLUSIONS: These results add to what is known about the geographic variation of diffuse large B-cell lymphomas. In northern China, the frequency of the germinal center B-cell-like type and BCL6 expression and/or BCL6 rearrangement is less and the frequency of MYC rearrangement is greater than have been reported in Western countries.

Focal cerebral ischemia in rats alters APP processing and expression of Abeta peptide degrading enzymes in the thalamus.

We have previously demonstrated aggregation of amyloid precursor protein (APP) and beta-amyloid (Abeta) to dense plaque-like deposits in the thalamus of rats subjected to transient middle cerebral artery occlusion (MCAO). Here, we investigated the underlying molecular effects of MCAO on APP processing and expression profiles of Abeta degrading enzymes in the cortex adjacent to the infarct (penumbra) and ipsilateral thalamus 2, 7 and 30 days after ischemic insult. Enhanced beta-amyloidogenic processing of APP and altered insulin degrading enzyme and neprilysin expression were observed in the thalamus, but not the penumbral cortex, 7 and 30 days after MCAO coinciding with increased calcium levels and beta-secretase (BACE) activity. Consecutively, increased BACE activity associated with depletion of BACE trafficking protein GGA3, suggesting a post-translational stabilization of BACE. These results demonstrate that focal cerebral ischemia leads to complex pathogenic events in the thalamus long after the initial insult.

Ginsenoside Rg3 promotes beta-amyloid peptide degradation by enhancing gene expression of neprilysin.

OBJECTIVES: It has been hypothesized that the accumulation of beta-amyloid peptide (Abeta) in the brain is a triggering event leading to the pathological cascade of Alzheimer's disease. The steady-state levels of Abeta are determined by the metabolic balance between anabolic and catabolic activity and the dysregulation of this activity leads to Alzheimer's disease. Recent evidence has shown that neprilysin (NEP) is the rate-limiting enzyme in the Abeta degradation in the brain. Ginseng, the root of Panax ginseng C.A. Meyer, is widely used as a tonic for the prevention and treatment of age-related disorders in China. We aimed to investigate the basis of this use. METHODS: In this study, we investigated the effect of ginsenoside Rg3, one of the major active components of ginseng, on the metabolism of Abeta40 and Abeta42 in SK-N-SH cells transfected with Swedish mutant beta-amyloid precursor protein (SweAPP). RESULTS: The ELISA result showed that Rg3 significantly reduced the levels of Abeta40 and Abeta42, 19.65 +/- 6.05%, 23.61 +/- 6.74%, respectively (P < 0.01). The Western blot analysis showed that Rg3 reduced the levels of Abeta40 and Abeta42 through enhancing NEP gene expression, and real-time PCR assay showed that 50 microM Rg3 could significantly enhance NEP gene expression (2.9 fold at 48 h). CONCLUSIONS: Our findings suggest that the Rg3 compound of ginseng may be useful for treating patients suffering with Alzheimer's disease.

Brain angiotensin-converting enzymes: role of angiotensin-converting enzyme 2 in processing angiotensin II in mice.

Angiotensin (Ang)-converting enzyme 2 (ACE2) metabolizes Ang II to the vasodilatory peptide Ang(1-7), while neprilysin (NEP) generates Ang(1-7) from Ang I. Experiments used novel Surface Enhanced Laser Desorption Ionization-Time of Flight (SELDI-TOF) mass spectroscopic (MS) assays to study Ang processing. Mass spectroscopy was used to measure proteolytic conversion of Ang peptide substrates to their specific peptide products. We compared ACE/ACE2 activity in plasma, brain and kidney from C57BL/6 and NEP(-/-) mice. Plasma or tissue extracts were incubated with Ang I or Ang II (1296 or 1045, m/z, respectively), and generated peptides were monitored with MS. Angiotensin-converting enzyme 2 activity was detected in kidney and brain, but not in plasma. Brain ACE2 activity was highest in hypothalamus. Angiotensin-converting enzyme 2 activity was inhibited by the specific ACE2 inhibitor, DX600 (10 microm, 99% inhibition), but not by the ACE inhibitor, captopril (10 microm). Both MS and colorimetric assays showed high ACE activity in plasma and kidney with low levels in brain. To extend these findings, ACE measurements were made in ACE overexpressing mice. Angiotensin-converting enzyme four-copy mice showed higher ACE activity in kidney and plasma with low levels in hypothalamus. In hypothalamus from NEP-/- mice, generation of Ang(1-7) from Ang I was decreased, suggesting a role for NEP in Ang metabolism. With Ang II as substrate, there was no difference between NEP-/- and wild-type control mice, indicating that other enzymes may contribute to generation of Ang(1-7). The data suggest a predominant role of hypothalamic ACE2 in the processing of Ang II, in contrast to ACE, which is most active in plasma.

[Effect of ginsenoside Rg1 on neprilysin expression induced by LPS in SK-N-SH cell line].

OBJECTIVE: To investigate the effect of ginsenoside Rg1 on the neprilysin (NeP) expression induced by LPS in SK-N-SH cell line. METHODS: MTT was used to measure the survival rate of SK-N-SH cultured with ginsenoside Rg1 at different concentrations (5, 10, 20 micromol/L) and LPS (50 mg/L). The expression of NEP was measured by RT-PCR. RESULT: The survival rate of SK-N-SH was obviously inhibited by LPS, the expression of NEP was decreased. On the other hand, the above alteration induced by LPS was reversed by ginsenoside Rg1. CONCLUSION: This study demonstrates that LPS can cause cell damage and the decrease of NEP expression. Ginsenoside Rg1 can protect SK-N-SH cells against the injury induced by LPS, increase NEP expression.

Ontogeny, regional and cellular distribution of the novel metalloprotease neprilysin 2 in the rat: a comparison with neprilysin and endothelin-converting enzyme-1.

The localisation of the gene transcripts of a recently discovered peptidase, neprilysin 2 (NEP2), was established by in situ hybridisation in rat tissues during development and adulthood. It was compared with those of neprilysin (NEP), a closely related enzyme in terms of sequence homology or substrate specificity, and of endothelin-converting enzyme 1 (ECE-1) which, like the other two, belongs to the M-13 sub-family of zinc-dependent metallopeptidases. The ontogeny of the three enzymes differed markedly, the expression of NEP2 being restricted to developing and differentiating fields of the CNS, whereas NEP and ECE-1 genes were broadly expressed early on in the CNS and periphery. In contrast to the wide expression of NEP and ECE-1 in peripheral adult tissues and in CNS, NEP2 was almost exclusively expressed in selected neuronal populations of the brain and spinal cord. The only exceptions were the intermediate and anterior lobes of the pituitary as well as the choroid plexuses, where NEP2 was also strongly expressed. These localisations as well as those in the hypothalamic nuclei, together with the previously established pattern of cleaved peptides, suggest the involvement of NEP2 in the metabolism of neurohormones of the hypothalamo-pituitary axis.Complementary distributions of NEP and NEP2 mRNAs were observed in a large number of brain areas with, for instance the former being highly expressed in the striatum in which NEP2 transcripts were almost undetectable. In contrast, NEP2 was highly expressed in numerous thalamic, hypothalamic and brainstem nuclei from which NEP was absent. Since both peptidases are able to cleave the same neuropeptides, this pattern may suggest a complementary role in their peptide inactivation functions in the CNS. Finally, ECE-1 mRNAs were generally observed in neuronal populations known to express the pre-proendothelin-1 gene, confirming the function of the metallopeptidase in endothelin-1 generation.

Isolation and expression of an ecdysteroid-inducible neutral endopeptidase 24.11-like gene in wing discs of Bombyx mori.

In the process of comparison of two cDNA libraries (W0, W2), we isolated a clone from the wing discs of Bombyx mori encoding a putative neutral endopeptidase 24.11-like gene. The predicted open reading frame encoded 772 amino acid residues, having about 53% identity with Drosophila GH07643, 36% with rat NEP, and 34% with rat ECE. This is the first NEP gene isolated in invertebrate. A 3.6-kb transcript was found to accumulate in the wing disc according to the increase of ecdysteroid titer during metamorphosis. Accumulation of the transcript was induced in wing discs with 20-hydroxyecdysone about 20h after incubation, which was inhibited by cycloheximide. This gene is ecdysone-inducible, appears to encode a functional protein, and may function during wing metamorphosis.

Molecular cloning, tissue distribution, and chromosomal localization of MMEL2, a gene coding for a novel human member of the neutral endopeptidase-24.11 family.

Members of the neutral endopeptidase (NEP, also known as MME for membrane metallo-endopeptidase in the Human Gene Nomenclature database) family play significant roles in pain perception, arterial pressure regulation, phosphate metabolism, and homeostasis. In this paper, we report the cloning of a new human member of the NEP family that we named MMEL2 for membrane metallo-endopeptidase-like 2. The MMEL2 protein has the structural characteristics of type II transmembrane proteins, although the presence of a furin-like cleavage site in the ectodomain suggests that it may be released into the medium following proteolytic cleavage. The MMEL2 protein contains the zinc-binding consensus sequence HEXXH and all the residues known to be essential for the enzymatic activity of other members of the family. The MMEL2 mRNA was detected predominantly in testis, but weak expression also was observed in brain, kidney, and heart. The human MMEL2 gene was mapped to 1p36 by fluorescence in situ hybridization. It will be important to test whether MMEL2 defects are associated with diseases such as hereditary motor sensory neuropathy 2A, Schwartz-Jampel-Aberfeld syndrome, or neuroblastoma, which all map to this locus.

Substance P is a determinant of lethality in diet-induced hemorrhagic pancreatitis in mice.

BACKGROUND: The neuropeptide substance P (SP) induces plasma extravasation and neutrophil infiltration by activating the neurokinin 1-receptor (NK1-R). SP-induced neurogenic inflammation is terminated by the cell surface enzyme neutral endopeptidase (NEP), which degrades SP. We determined whether genetic deletion of the NK1-R reduces mortality and, conversely, whether genetic deletion of NEP increases mortality in a lethal model of hemorrhagic pancreatitis. METHODS: Necrotizing pancreatitis was induced by feeding mice a diet deficient in choline and supplemented with ethionine. We determined the length of survival, the severity of pancreatitis (by measuring the neutrophil enzyme myeloperoxidase [MPO] and by histologic evaluation), and the severity of pancreatitis-associated lung injury (lung MPO and histology) in NK1-R (+/+)/(-/-) and NEP (+/+)/(-/-) mice. RESULTS: Genetic deletion of the NK1-R significantly improved survival (100% vs 8% at 120 hours, P <.001) and reduced pancreatic MPO and acinar cell necrosis. Conversely, genetic deletion of NEP significantly worsened survival (0% vs 90% at 120 hours, P <.001) and exacerbated pancreatic MPO and pancreatitis-associated lung injury. CONCLUSIONS: Substance P is an important determinant of lethality in this model of necrotizing pancreatitis. Defects in NEP expression could lead to uncontrolled inflammation.