Sample records for metalloendopeptidases

  1. Natural Inhibitors of Snake Venom Metalloendopeptidases: History and Current Challenges

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    Viviane A. Bastos


    Full Text Available The research on natural snake venom metalloendopeptidase inhibitors (SVMPIs began in the 18th century with the pioneering work of Fontana on the resistance that vipers exhibited to their own venom. During the past 40 years, SVMPIs have been isolated mainly from the sera of resistant animals, and characterized to different extents. They are acidic oligomeric glycoproteins that remain biologically active over a wide range of pH and temperature values. Based on primary structure determination, mammalian plasmatic SVMPIs are classified as members of the immunoglobulin (Ig supergene protein family, while the one isolated from muscle belongs to the ficolin/opsonin P35 family. On the other hand, SVMPIs from snake plasma have been placed in the cystatin superfamily. These natural antitoxins constitute the first line of defense against snake venoms, inhibiting the catalytic activities of snake venom metalloendopeptidases through the establishment of high-affinity, non-covalent interactions. This review presents a historical account of the field of natural resistance, summarizing its main discoveries and current challenges, which are mostly related to the limitations that preclude three-dimensional structural determinations of these inhibitors using “gold-standard” methods; perspectives on how to circumvent such limitations are presented. Potential applications of these SVMPIs in medicine are also highlighted.

  2. Controlled Autolysis and Enzyme Release in a Recombinant Lactococcal Strain Expressing the Metalloendopeptidase Enterolysin A (United States)

    Hickey, Rita M.; Ross, R. Paul; Hill, Colin


    This study concerns the exploitation of the lytic enzyme enterolysin A (EntL), produced by Enterococcus faecalis strain DPC5280, to elicit the controlled autolysis of starter lactococci. EntL, a cell wall metalloendopeptidase secreted by some E. faecalis strains, can kill a wide range of gram-positive bacteria, including lactococci. The controlled expression of entL, which encodes EntL, was achieved using a nisin-inducible expression system in a lactococcal host. Zymographic analysis of EntL activity demonstrated that active enzyme is produced by the recombinant lactococcal host. Indeed, expression of EntL resulted in almost complete autolysis of the host strain 2 h after induction with nisin. Model cheese experiments using a starter strain in addition to the inducible enterolysin-producing strain showed a 27-fold increase in activity with respect to the release of lactate dehydrogenase in the strain overexpressing EntL, demonstrating the potential of EntL production in large-scale cheese production systems. Indeed, the observation that a wide range of lactic bacteria are sensitive to EntL suggests that EntL-induced autolysis has potential applications with a variety of lactic acid bacteria and could be a basis for probiotic delivery systems. PMID:15006800

  3. A liver metalloendopeptidase which degrades the circulating hypotensive peptide hormones bradykinin and atrial natriuretic peptide

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    Carvalho K.M.


    Full Text Available A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human liver using successive steps of chromatography on DEAE-cellulose, hydroxyapatite and Sephacryl S-200. The purified enzyme hydrolyzed the Pro7-Phe8 bond of bradykinin and the Ser25-Tyr26 bond of atrial natriuretic peptide. No cleavage was produced in other peptide hormones such as vasopressin, oxytocin or Met- and Leu-enkephalin. This enzyme activity was inhibited by 1 mM divalent cation chelators such as EDTA, EGTA and o-phenanthroline and was insensitive to 1 µM phosphoramidon and captopril, specific inhibitors of neutral endopeptidase (EC and angiotensin-converting enzyme (EC, respectively. With Mr 85 kDa, the enzyme exhibits optimal activity at pH 7.5. The high affinity of this endopeptidase for bradykinin (Km = 10 µM and for atrial natriuretic peptide (Km = 5 µM suggests that it may play a physiological role in the inactivation of these circulating hypotensive peptide hormones.

  4. A new brain metalloendopeptidase which degrades the Alzheimer ß-amyloid 1-40 peptide producing soluble fragments without neurotoxic effects

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    K.M. Carvalho


    Full Text Available A new metalloendopeptidase was purified to apparent homogeneity from a homogenate of normal human brain using successive steps of chromatography on DEAE-Trisacryl, hydroxylapatite and Sephacryl S-200. The purified enzyme cleaved the Gly33-Leu34 bond of the 25-35 neurotoxic sequence of the Alzheimer ß-amyloid 1-40 peptide producing soluble fragments without neurotoxic effects. This enzyme activity was only inhibited by divalent cation chelators such as EDTA, EGTA and o-phenanthroline (1 mM and was insensitive to phosphoramidon and captopril (1 µM concentration, specific inhibitors of neutral endopeptidase (EC and angiotensin-converting enzyme (EC, respectively. The high affinity of this human brain endopeptidase for ß-amyloid 1-40 peptide (Km = 5 µM suggests that it may play a physiological role in the degradation of this substance produced by normal cellular metabolism. It may also be hypothesized that the abnormal accumulation of the amyloid ß-protein in Alzheimer's disease may be initiated by a defect or an inactivation of this enzyme.

  5. Hypoxia increases membrane metallo-endopeptidase expression in a novel lung cancer ex vivo model - role of tumor stroma cells

    NARCIS (Netherlands)

    K. Leithner (Katharina); C. Wohlkoenig (Christoph); E. Stacher (Elvira); J. Lindenmann (Jörg); N.A. Hofmann (Nicole); B. Gallé (Birgit); C. Guelly (Christian); F. Quehenberger (Franz); P. Stiegler (Philipp); F.-M. Smolle-Jüttner (Freyja-Maria); J.N.J. Philipsen (Sjaak); H.H. Popper (Helmut); A. Hrzenjak (Andelko); A. Olschewski (Andrea); H. Olschewski (Horst)


    textabstractBackground: Hypoxia-induced genes are potential targets in cancer therapy. Responses to hypoxia have been extensively studied in vitro, however, they may differ in vivo due to the specific tumor microenvironment. In this study gene expression profiles were obtained from fresh human lung

  6. Interactions of a new alpha-aminophosphinic derivative inside the active site of TLN (thermolysin): a model for zinc-metalloendopeptidase inhibition. (United States)

    Selkti, Mohamed; Tomas, Alain; Gaucher, Jean-François; Prangé, Thierry; Fournié-Zaluski, Marie-Claude; Chen, Huixiong; Roques, Bernard-Pierre


    A new alpha-aminophosphinic compound able to inhibit both zinc-containing exopeptidases and endopeptidases has been crystallized with TLN as a model in order to investigate the mode of zinc recognition by the phosphinic moiety and to evaluate the potential role of the free alpha-amino group in the formation of enzyme-inhibitor complexes. In addition to the main interactions between the backbone of the inhibitor and the enzyme active site, it is observed that the phosphinic group acts as a distorted bidentate ligand for the zinc ion, while the free alpha-amino function does not directly participate in interactions within the active site. Association of the present data and the K(i) values of various analogues of the inhibitor towards TLN and neprilysin suggests differences in the hydrophobicity of the S(1)-S(2) domains of the enzymes. This could be taken into account in the design of selective inhibitors.

  7. Crystal structures of alpha-mercaptoacyldipeptides in the thermolysin active site: structural parameters for a Zn monodentation or bidentation in metalloendopeptidases. (United States)

    Gaucher, J F; Selkti, M; Tiraboschi, G; Prangé, T; Roques, B P; Tomas, A; Fournié-Zaluski, M C


    Three alpha-mercaptoacyldipeptides differing essentially in the size of their C-terminal residues have been crystallized in the thermolysin active site. A new mode of binding was observed for 3 [HS-CH(CH(2)Ph)CO-Phe-Tyr] and 4 [HS-CH((CH(2))(4)CH(3))CO-Phe-Ala], in which the mercaptoacyl moieties act as bidentates with Zn-S and Zn-O distances of 2.3 and 2.4 A, respectively, the side chains fitting the S(1), S(1)', and S(2)' pockets. Moreover, a distance of 3.1 A between the sulfur atom and the OE1 of Glu(143) suggests that they are H-bonded and that one of these atoms is protonated. This H-bond network involving Glu(143), the mercaptoacyl group of the inhibitor, and the Zn ion could be considered a "modified" transition state mimic of the peptide bond hydrolysis. Due to the presence of the hindering (5-phenyl)proline, the inhibitor HS-CH(CH(2)Ph)CO-Gly-(5-Ph)Pro (2) interacts through the usual Zn monodentation via the thiol group and occupancy of S(1)' and S(2)' subsites by the aromatic moieties, the proline ring being outside the active site. The inhibitory potencies are consistent with these structural data, with higher affinities for 3 (4.2 x 10(-)(8) M) and 4 (4.8 x 10(-)(8) M) than for 2 (1.2 x 10(-)(6) M). The extension of the results, obtained with thermolysin being considered as the model of physiological zinc metallopeptidases, allows inhibitor-recognition modes for other peptidases, such as angiotensin converting enzyme and neutral endopeptidase, to be proposed and opens interesting possibilities for the design of new classes of inhibitors.

  8. Co-suppression of sterol-regulatory element binding protein ...

    African Journals Online (AJOL)



    Jun 22, 2011 ... In Arabidopsis,. At5g35220 gene being sterol regulatory element-binding protein site 2, protease and metalloendopeptidase activity were required for chloroplast development and play a role in regulation of endodermal plastid size and number that are involved in ethylene-dependent gravitropism of light-.

  9. Immunocapture-based fluorometric assay for the measurement of neprilysin-specific enzyme activity in brain tissue homogenates and cerebrospinal fluid.

    NARCIS (Netherlands)

    Miners, J.S.; Verbeek, M.M.; Olde Rikkert, M.G.M.; Kehoe, P.G.; Love, S.


    Neprilysin, a zinc-metalloendopeptidase, has important roles in the physiology and pathology of many diseases such as hypertension, cancer and Alzheimer's disease. We have developed an immunocapture assay to measure the specific enzyme activity of neprilysin in brain tissue homogenates and

  10. Multienzyme Modification of Hemp Protein for Functional Peptides Synthesis

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    Ranjana Das


    Full Text Available Functional foods and nutraceuticals are of special importance, particularly for their impact on human health and prevention of certain chronic diseases. Consequently, the production and properties of bioactive peptides have received an increasing scientific interest over past few years. Present work intends to compare the competence of metalloendopeptidases (“Protease N” and “Protease A” with papain for getting functional peptides from hemp seed meal, which is an obligatory waste of hemp fiber production industry. As a measure of the functional potential hemp protein hydrolysates were analyzed for their antiradical properties in DPPH system. “Protease N” modified protein hydrolysate exhibited comparatively superior radical scavenging activity in DPPH system. Overall findings represent the importance of “Protease N,” as endopeptidase in getting peptides of good antiradical properties from various protein sources.

  11. Sequencing Lys-N Proteolytic Peptides by ESI and MALDI Tandem Mass Spectrometry (United States)

    Dupré, Mathieu; Cantel, Sonia; Verdié, Pascal; Martinez, Jean; Enjalbal, Christine


    In this study, we explored the MS/MS behavior of various synthetic peptides that possess a lysine residue at the N-terminal position. These peptides were designed to mimic peptides produced upon proteolysis by the Lys-N enzyme, a metalloendopeptidase issued from a Japanese fungus Grifola frondosa that was recently investigated in proteomic studies as an alternative to trypsin digestion, as a specific cleavage at the amide X-Lys chain is obtained that provides N-terminal lysine peptide fragments. In contrast to tryptic peptides exhibiting a lysine or arginine residue solely at the C-terminal position, and are thus devoid of such basic amino acids within the sequence, these Lys-N proteolytic peptides can contain the highly basic arginine residue anywhere within the peptide chain. The fragmentation patterns of such sequences with the ESI-QqTOF and MALDI-TOF/TOF mass spectrometers commonly used in proteomic bottom-up experiments were investigated.

  12. Mycoplasma hyopneumoniae in vitro peptidase activities: identification and cleavage of kallikrein-kinin system-like substrates. (United States)

    Moitinho-Silva, Lucas; Kondo, Marcia Y; Oliveira, Lilian C G; Okamoto, Debora N; Paes, Jéssica A; Machado, Mauricio F M; Veronez, Camila L; Motta, Guacyara; Andrade, Sheila S; Juliano, Maria A; Ferreira, Henrique B; Juliano, Luiz; Gouvea, Iuri E


    Bacterial proteases are important for metabolic processes and pathogenesis in host organisms. The bacterial swine pathogen Mycoplasma hyopneumoniae has 15 putative protease-encoding genes annotated, but none of them have been functionally characterized. To identify and characterize peptidases that could be relevant for infection of swine hosts, we investigated the peptidase activity present in the pathogenic 7448 strain of M. hyopneumoniae. Combinatorial libraries of fluorescence resonance energy transfer peptides, specific inhibitors and pH profiling were used to screen and characterize endopeptidase, aminopeptidase and carboxypeptidase activities in cell lysates. One metalloendopeptidase, one serine endopeptidase, and one aminopeptidase were detected. The detected metalloendopeptidase activity, prominent at neutral and basic pH ranges, was due to a thimet oligopeptidase family member (M3 family), likely an oligoendopeptidase F (PepF), which cleaved the peptide Abz-GFSPFRQ-EDDnp at the F-S bond. A chymotrypsin-like serine endopeptidase activity, possibly a subtilisin-like serine protease, was prominent at higher pH levels, and was characterized by its preference for a Phe residue at the P1 position of the substrate. The aminopeptidase P (APP) activity showed a similar profile to that of human membrane-bound APP. Genes coding for these three peptidases were identified and their transcription was confirmed in the 7448 strain. Furthermore, M. hyopneumoniae cell lysate peptidases showed effects on kallikrein-kinin system-like substrates, such as bradykinin-derived substrates and human high molecular weight kininogen. The M. hyopneumoniae peptidase activities, here characterized for the first time, may be important for bacterial survival strategies and thus represent possible targets for drug development against M. hyopneumoniae swine infections. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. Degradation of bradykinin by isolated perfused rat lung

    International Nuclear Information System (INIS)

    Churchill, M.; Orawski, A.T.; AchutaMurthy, P.N.; Simmons, W.H.


    Several studies have suggested that the essentially complete degradation of circulating bradykinin (BK) in lung is mediated in part by peptidase(s) other than the well-characterized angiotensin converting enzyme (ACE). The authors report here that the isolated perfused rat lung can inactivate BK by sequential N-terminal cleavage. [ 3 H-2, 3-Pro] BK was perfused through the lung and the products in the perfusate identified by HPLC. In the absence of inhibitors, BK was 89-100% degraded with 3 H-Pro 2 -Pro 3 and 3 H-Pro as the major products. The dipeptidylaminopeptidase IV (DAP IV) inhibitor, diprotein A (Ile-Pro-Ile), greatly reduced the Pro-Pro and Pro peaks and produced a prominent BK/sub 2-7/ peak (or BK/sub 2-9/ peak if the ACE inhibitor, captopril, was also present). 2-Mercapto-ethanol, a rather specific inhibitor of aminopeptidase P (AP-P), prevented the release of Arg 1 , producing major BK and/or BK/sub 1-7/ peaks. The neutral metalloendopeptidase inhibitor, phosphoramidon, had no effect on the pattern of degradation of BK by the perfused rat lung by the release of Arg 1 by AP-P followed by release of Pro 2 -Pro 3 by DAP IV

  14. Mycobacterium leprae downregulates the expression of PHEX in Schwann cells and osteoblasts

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    Sandra R Boiça Silva


    Full Text Available Neuropathy and bone deformities, lifelong sequelae of leprosy that persist after treatment, result in significant impairment to patients and compromise their social rehabilitation. Phosphate-regulating gene with homologies to endopeptidase on the X chromosome (PHEX is a Zn-metalloendopeptidase, which is abundantly expressed in osteoblasts and many other cell types, such as Schwann cells, and has been implicated in phosphate metabolism and X-linked rickets. Here, we demonstrate that Mycobacterium leprae stimulation downregulates PHEX transcription and protein expression in a human schwannoma cell line (ST88-14 and human osteoblast lineage. Modulation of PHEX expression was observed to a lesser extent in cells stimulated with other species of mycobacteria, but was not observed in cultures treated with latex beads or with the facultative intracellular bacterium Salmonella typhimurium. Direct downregulation of PHEX by M. leprae could be involved in the bone resorption observed in leprosy patients. This is the first report to describe PHEX modulation by an infectious agent.

  15. Cloning, sequencing and expression of the gene encoding the extracellular metalloprotease of Aeromonas caviae. (United States)

    Kawakami, K; Toma, C; Honma, Y


    A gene (apk) encoding the extracellular protease of Aeromonas caviae Ae6 has been cloned and sequenced. For cloning the gene, the DNA genomic library was screened using skim milk LB agar. One clone harboring plasmid pKK3 was selected for sequencing. Nucleotide sequencing of the 3.5 kb region of pKK3 revealed a single open reading frame (ORF) of 1,785 bp encoding 595 amino acids. The deduced polypeptide contained a putative 16-amino acid signal peptide followed by a large propeptide. The N-terminal amino acid sequence of purified recombinant protein (APK) was consistent with the DNA sequence. This result suggested a mature protein of 412 amino acids with a molecular mass of 44 kDa. However, the molecular mass of purified recombinant APK revealed 34 kDa by SDS-PAGE, suggesting that further processing at the C-terminal region took place. The 2 motifs of zinc binding sites deduced are highly conserved in the APK as well as in other zinc metalloproteases including Vibrio proteolyticus neutral protease, Emp V from Vibrio vulnificus, HA/P from Vibrio cholerae, and Pseudomonas aeruginosa elastase. Proteolytic activity was inhibited by EDTA, Zincov, 1,10-phenanthroline and tetraethylenepentamine while unaffected by the other inhibitors tested. The protease showed maximum activity at pH 7.0 and was inactivated by heating at 80 C for 15 min. These results together suggest that APK belongs to the thermolysin family of metalloendopeptidases.

  16. The protein-protein interactions between SMPI and thermolysin studied by molecular dynamics and MM/PBSA calculations. (United States)

    Adekoya, Olayiwola A; Willassen, Nils-Peder; Sylte, Ingebrigt


    Thermolysin is a zinc-metalloendopeptidase secreted by the gram-positive thermophilic bacterium Bacillus thermoproteolyticus. Thermolysin belongs to the gluzinicin family of enzymes, which is selectively inhibited by Steptomyces metalloproteinase inhibitor (SMPI). Very little is known about the interaction between SMPI and thermolysin. Knowledge about the protein-protein interactions is very important for designing new thermolysin inhibitors with possible industrial or pharmaceutical applications. In the present study, two binding modes between SMPI and thermolysin were studied by 2300 picoseconds (ps) of comparative molecular dynamics (MD) simulations and calculation of the free energy of binding using the molecular mechanics-Poisson-Boltmann surface area (MM/PBSA) method. One of the positions, the 'horizontal arrow head docking' (HAHD) was similar to the previously proposed binding mode by Tate et al. (Tate, S., Ohno, A., Seeram, S. S., Hiraga, K., Oda, K., and Kainosho, M. J. Mol. Biol. 282, 435-446 (1998)). The other position, the 'vertical arrow head docking' (VAHD) was obtained by a manual docking guided by the shape and charge distribution of SMPI and the binding pocket of thermolysin. The calculations showed that SMPI had stronger interactions with thermolysin in the VAHD than in the HAHD complex, and the VAHD complex was considered more realistic than the HAHD complex. SMPI interacted with thermolysin not only at the active site but had auxiliary binding sites contributing to proper interactions. The VAHD complex can be used for designing small molecule inhibitors mimicking the SMPI-thermolysin binding interfaces.

  17. Reduced Fertility in Male Mice Deficient in the Zinc Metallopeptidase NL1 (United States)

    Carpentier, Mélanie; Guillemette, Christine; Bailey, Janice L.; Boileau, Guy; Jeannotte, Lucie; DesGroseillers, Luc; Charron, Jean


    Members of the M13 family of zinc metalloendopeptidases have been shown to play critical roles in the metabolism of various neuropeptides and peptide hormones, and they have been identified as important therapeutic targets. Recently, a mouse NL1 protein, a novel member of the family, was identified and shown to be expressed mainly in the testis as a secreted protein. To define its physiological role(s), we used a gene targeting strategy to disrupt the endogenous murine Nl1 gene by homologous recombination and generate Nl1 mutant mice. The Nl1−/− mice were viable and developed normally, suggesting that zygotic expression of Nl1 is not required for development. However, Nl1−/− males produced smaller litters than their wild-type siblings, indicating specific male fertility problems. Reduced fertility may be explained by two impaired processes, decreased egg fertilization and perturbed early development of fertilized eggs. These two phenotypes did not result from gross anatomical modifications of the testis or from impaired spermatogenesis. Basic sperm parameters were also normal. Thus, our findings suggest that one of the roles of NL1 in mice is related to sperm function and that NL1 modulates the processes of fertilization and early embryonic development in vivo. PMID:15121861

  18. Differential Properties of Venom Peptides and Proteins in Solitary vs. Social Hunting Wasps (United States)

    Lee, Si Hyeock; Baek, Ji Hyeong; Yoon, Kyungjae Andrew


    The primary functions of venoms from solitary and social wasps are different. Whereas most solitary wasps sting their prey to paralyze and preserve it, without killing, as the provisions for their progeny, social wasps usually sting to defend their colonies from vertebrate predators. Such distinctive venom properties of solitary and social wasps suggest that the main venom components are likely to be different depending on the wasps’ sociality. The present paper reviews venom components and properties of the Aculeata hunting wasps, with a particular emphasis on the comparative aspects of venom compositions and properties between solitary and social wasps. Common components in both solitary and social wasp venoms include hyaluronidase, phospholipase A2, metalloendopeptidase, etc. Although it has been expected that more diverse bioactive components with the functions of prey inactivation and physiology manipulation are present in solitary wasps, available studies on venom compositions of solitary wasps are simply too scarce to generalize this notion. Nevertheless, some neurotoxic peptides (e.g., pompilidotoxin and dendrotoxin-like peptide) and proteins (e.g., insulin-like peptide binding protein) appear to be specific to solitary wasp venom. In contrast, several proteins, such as venom allergen 5 protein, venom acid phosphatase, and various phospholipases, appear to be relatively more specific to social wasp venom. Finally, putative functions of main venom components and their application are also discussed. PMID:26805885

  19. Purification and characterization of a novel fibrinolytic enzyme from culture supernatant of Pleurotus ostreatus. (United States)

    Liu, Xiao-Lan; Zheng, Xi-Qun; Qian, Peng-Zhi; Kopparapu, Narasimha-Kumar; Deng, Yong-Ping; Nonaka, Masanori; Harada, Naoki


    A fibrinolytic enzyme was produced by an edible mushroom of Pleurotus ostreatus using submerged culture fermentation. The enzyme was purified from the culture supernatant by applying a combination of freeze-thaw treatment, ammonium sulfate precipitation, hydrophobic interaction, and gel filtration chromatographies. The enzyme was purified by a 147-fold, with a yield of 7.54%. The molecular masses of the enzyme an determined by gel filtration and SDSPAGE were 13.6 and 18.2 kDa, respectively. The isoelectric point of the enzyme was 8.52. It hydrolyzed fibrinogen by cleaving the α and β chains of fibrinogen followed by the γ chains, and also activated plasminogen into plasmin. The enzyme was optimally active at 45°C and pH 7.4. The enzyme activity was completely inhibited by EDTA, whereas protease inhibitors of TPCK, SBTI, PMSF, aprotinin and pepstatin showed no inhibition on its activity. The partial amino acid sequences of the enzyme as determined by Q-TOF2 were ATFVGCSATR, GGTLIHESSHFTR, and YTTWFGTFVTSR. These sequences showed a high degree of homology with those of metallo-endopeptidases from P. ostreatus and Armillaria mellea. The purified enzyme can also be applied as a natural agent for oral fibrinolytic therapy or prevention of thrombosis.

  20. Spatiotemporal expression of endogenous opioid processing enzymes in mouse uterus at peri-implantation. (United States)

    Wu, Weiwei; Kong, Shuangbo; Wang, Bingyan; Chen, Yongjie; Wang, Haibin


    Successful implantation requires intimate interactions between a competent blastocyst and a receptive uterus. We recently demonstrated that the aberrant activation of opioid signaling by exogenous ligands adversely affects preimplantation embryonic development and subsequent implantation in mice. However, the underlying machinery governing the dynamic homeostasis of the endogenous opioid system in the uterus during early pregnancy remains elusive. We now show that all three major endogenous opioid precursors are spatiotemporally expressed in the uterus during early pregnancy. Moreover, we observe the well-coordinated expression of the synthetic enzyme prohormone convertases 1/3 (PC1/3) at lower levels and of its inhibitor proprotein convertase subtilisin/kexin type 1 inhibitor (Pcsk1n) and the degrading enzyme membrane metallo-endopeptidase (MME) at higher levels in the receptive uterus. Both estrogen and progestin tend to reduce the uterine levels of opioid ligand precursors in the ovariectomized mouse model. This tight regulation of the endogenous opioid system by PC1/3, Pcsk1n and MME has been further confirmed in physiologically related pseudopregnancy and delayed implantation mouse models. The coordinated regulation of opioid precursor biosynthesis and metabolism helps to create appropriate opioid signaling ensuring uterine receptivity for implantation. Thus, endogenous uterine opioid levels are primarily determined by the coordinated expressions of PC1/3, Pcsk1n and MME under the influence of ovarian progestin and estrogen. Our findings raise an additional cautionary note regarding the effects of opioid abuse on early pregnancy events.

  1. Casodex treatment induces hypoxia-related gene expression in the LNCaP prostate cancer progression model

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    Gopalakrishnan Velliyur K


    Full Text Available Abstract Background The changes in gene expression profile as prostate cancer progresses from an androgen-dependent disease to an androgen-independent disease are still largely unknown. Methods We examined the gene expression profile in the LNCaP prostate cancer progression model during chronic treatment with Casodex using cDNA microarrays consisting of 2305 randomly chosen genes. Results Our studies revealed a representative collection of genes whose expression was differentially regulated in LNCaP cells upon treatment with Casodex. A set of 15 genes were shown to be highly expressed in Casodex-treated LNCaP cells compared to the reference sample. This set of highly expressed genes represents a signature collection unique to prostate cancer since their expression was significantly greater than that of the collective pool of ten cancer cell lines of the reference sample. The highly expressed signature collection included the hypoxia-related genes membrane metallo-endopeptidase (MME, cyclin G2, and Bcl2/adenovirus E1B 19 kDa (BNIP3. Given the roles of these genes in angiogenesis, cell cycle regulation, and apoptosis, we further analyzed their expression and concluded that these genes may be involved in the molecular changes that lead to androgen-independence in prostate cancer. Conclusion Our data indicate that one of the mechanisms of Casodex action in prostate cancer cells is induction of hypoxic gene expression.

  2. Peptidic inhibitors of insulin-degrading enzyme with potential for dermatological applications discovered via phage display.

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    Caitlin N Suire

    Full Text Available Insulin-degrading enzyme (IDE is an atypical zinc-metalloendopeptidase that hydrolyzes insulin and other intermediate-sized peptide hormones, many of which are implicated in skin health and wound healing. Pharmacological inhibitors of IDE administered internally have been shown to slow the breakdown of insulin and thereby potentiate insulin action. Given the importance of insulin and other IDE substrates for a variety of dermatological processes, pharmacological inhibitors of IDE suitable for topical applications would be expected to hold significant therapeutic and cosmetic potential. Existing IDE inhibitors, however, are prohibitively expensive, difficult to synthesize and of undetermined toxicity. Here we used phage display to discover novel peptidic inhibitors of IDE, which were subsequently characterized in vitro and in cell culture assays. Among several peptide sequences tested, a cyclic dodecapeptide dubbed P12-3A was found to potently inhibit the degradation of insulin (Ki = 2.5 ± 0.31 μM and other substrates by IDE, while also being resistant to degradation, stable in biological milieu, and highly selective for IDE. In cell culture, P12-3A was shown to potentiate several insulin-induced processes, including the transcription, translation and secretion of alpha-1 type I collagen in primary murine skin fibroblasts, and the migration of keratinocytes in a scratch wound migration assay. By virtue of its potency, stability, specificity for IDE, low cost of synthesis, and demonstrated ability to potentiate insulin-induced processes involved in wound healing and skin health, P12-3A holds significant therapeutic and cosmetic potential for topical applications.

  3. gone early, a novel germline factor, ensures the proper size of the stem cell precursor pool in the Drosophila ovary.

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    Shinya Matsuoka

    Full Text Available In order to sustain lifelong production of gametes, many animals have evolved a stem cell-based gametogenic program. In the Drosophila ovary, germline stem cells (GSCs arise from a pool of primordial germ cells (PGCs that remain undifferentiated even after gametogenesis has initiated. The decision of PGCs to differentiate or remain undifferentiated is regulated by somatic stromal cells: specifically, epidermal growth factor receptor (EGFR signaling activated in the stromal cells determines the fraction of germ cells that remain undifferentiated by shaping a Decapentaplegic (Dpp gradient that represses PGC differentiation. However, little is known about the contribution of germ cells to this process. Here we show that a novel germline factor, Gone early (Goe, limits the fraction of PGCs that initiate gametogenesis. goe encodes a non-peptidase homologue of the Neprilysin family metalloendopeptidases. At the onset of gametogenesis, Goe was localized on the germ cell membrane in the ovary, suggesting that it functions in a peptidase-independent manner in cell-cell communication at the cell surface. Overexpression of Goe in the germline decreased the number of PGCs that enter the gametogenic pathway, thereby increasing the proportion of undifferentiated PGCs. Inversely, depletion of Goe increased the number of PGCs initiating differentiation. Excess PGC differentiation in the goe mutant was augmented by halving the dose of argos, a somatically expressed inhibitor of EGFR signaling. This increase in PGC differentiation resulted in a massive decrease in the number of undifferentiated PGCs, and ultimately led to insufficient formation of GSCs. Thus, acting cooperatively with a somatic regulator of EGFR signaling, the germline factor goe plays a critical role in securing the proper size of the GSC precursor pool. Because goe can suppress EGFR signaling activity and is expressed in EGF-producing cells in various tissues, goe may function by attenuating

  4. Mutations in MME cause an autosomal‐recessive Charcot–Marie–Tooth disease type 2 (United States)

    Higuchi, Yujiro; Hashiguchi, Akihiro; Yuan, Junhui; Yoshimura, Akiko; Mitsui, Jun; Ishiura, Hiroyuki; Tanaka, Masaki; Ishihara, Satoshi; Tanabe, Hajime; Nozuma, Satoshi; Okamoto, Yuji; Matsuura, Eiji; Ohkubo, Ryuichi; Inamizu, Saeko; Shiraishi, Wataru; Yamasaki, Ryo; Ohyagi, Yasumasa; Kira, Jun‐ichi; Oya, Yasushi; Yabe, Hayato; Nishikawa, Noriko; Tobisawa, Shinsuke; Matsuda, Nozomu; Masuda, Masayuki; Kugimoto, Chiharu; Fukushima, Kazuhiro; Yano, Satoshi; Yoshimura, Jun; Doi, Koichiro; Nakagawa, Masanori; Morishita, Shinichi; Tsuji, Shoji


    Objective The objective of this study was to identify new causes of Charcot–Marie–Tooth (CMT) disease in patients with autosomal‐recessive (AR) CMT. Methods To efficiently identify novel causative genes for AR‐CMT, we analyzed 303 unrelated Japanese patients with CMT using whole‐exome sequencing and extracted recessive variants/genes shared among multiple patients. We performed mutation screening of the newly identified membrane metalloendopeptidase (MME) gene in 354 additional patients with CMT. We clinically, genetically, pathologically, and radiologically examined 10 patients with the MME mutation. Results We identified recessive mutations in MME in 10 patients. The MME gene encodes neprilysin (NEP), which is well known to be one of the most prominent beta‐amyloid (Aβ)‐degrading enzymes. All patients had a similar phenotype consistent with late‐onset axonal neuropathy. They showed muscle weakness, atrophy, and sensory disturbance in the lower extremities. All the MME mutations could be loss‐of‐function mutations, and we confirmed a lack/decrease of NEP protein expression in a peripheral nerve. No patients showed symptoms of dementia, and 1 patient showed no excess Aβ in Pittsburgh compound‐B positron emission tomography imaging. Interpretation Our results indicate that loss‐of‐function MME mutations are the most frequent cause of adult‐onset AR‐CMT2 in Japan, and we propose that this new disease should be termed AR‐CMT2T. A loss‐of‐function MME mutation did not cause early‐onset Alzheimer's disease. Identifying the MME mutation responsible for AR‐CMT could improve the rate of molecular diagnosis and the understanding of the molecular mechanisms of CMT. Ann Neurol 2016;79:659–672 PMID:26991897

  5. Involvement of insulin-degrading enzyme in the clearance of beta-amyloid at the blood-CSF barrier: Consequences of lead exposure

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    Zhang Yanshu


    Full Text Available Abstract Background Alzheimer's disease (AD is characterized by the deposition of beta-amyloid (Aβ peptides in the brain extracellular matrix, resulting in pathological changes and neurobehavioral deficits. Previous work from this laboratory demonstrated that the choroid plexus (CP possesses the capacity to remove Aβ from the cerebrospinal fluid (CSF, and exposure to lead (Pb compromises this function. Since metalloendopeptidase insulin-degrading enzyme (IDE, has been implicated in the metabolism of Aβ, we sought to investigate whether accumulation of Aβ following Pb exposure was due to the effect of Pb on IDE. Methods Rats were injected with a single dose of Pb acetate or an equivalent concentration of Na-acetate; CP tissues were processed to detect the location of IDE by immunohistochemistry. For in vitro studies, choroidal epithelial Z310 cells were treated with Pb for 24 h in the presence or absence of a known IDE inhibitor, N-ethylmaleimide (NEM to assess IDE enzymatic activity and subsequent metabolic clearance of Aβ. Additionally, the expression of IDE mRNA and protein were determined using real time PCR and western blots respectively. Results Immunohistochemistry and confocal imaging revealed the presence of IDE towards the apical surface of the CP tissue with no visible alteration in either its intensity or location following Pb exposure. There was no significant difference in the expressions of either IDE mRNA or protein following Pb exposure compared to controls either in CP tissues or in Z310 cells. However, our findings revealed a significant decrease in the IDE activity following Pb exposure; this inhibition was similar to that seen in the cells treated with NEM alone. Interestingly, treatment with Pb or NEM alone significantly increased the levels of intracellular Aβ, and a greater accumulation of Aβ was seen when the cells were exposed to a combination of both. Conclusion These data suggest that Pb exposure inhibits IDE

  6. Proteolysis of mature HIV-1 p6 Gag protein by the insulin-degrading enzyme (IDE) regulates virus replication in an Env-dependent manner. (United States)

    Hahn, Friedrich; Schmalen, Adrian; Setz, Christian; Friedrich, Melanie; Schlößer, Stefan; Kölle, Julia; Spranger, Robert; Rauch, Pia; Fraedrich, Kirsten; Reif, Tatjana; Karius-Fischer, Julia; Balasubramanyam, Ashok; Henklein, Petra; Fossen, Torgils; Schubert, Ulrich


    There is a significantly higher risk for type II diabetes in HIV-1 carriers, albeit the molecular mechanism for this HIV-related pathology remains enigmatic. The 52 amino acid HIV-1 p6 Gag protein is synthesized as the C-terminal part of the Gag polyprotein Pr55. In this context, p6 promotes virus release by its two late (L-) domains, and facilitates the incorporation of the viral accessory protein Vpr. However, the function of p6 in its mature form, after proteolytic release from Gag, has not been investigated yet. We found that the mature p6 represents the first known viral substrate of the ubiquitously expressed cytosolic metalloendopeptidase insulin-degrading enzyme (IDE). IDE is sufficient and required for degradation of p6, and p6 is approximately 100-fold more efficiently degraded by IDE than its eponymous substrate insulin. This observation appears to be specific for HIV-1, as p6 proteins from HIV-2 and simian immunodeficiency virus, as well as the 51 amino acid p9 from equine infectious anaemia virus were insensitive to IDE degradation. The amount of virus-associated p6, as well as the efficiency of release and maturation of progeny viruses does not depend on the presence of IDE in the host cells, as it was shown by CRISPR/Cas9 edited IDE KO cells. However, HIV-1 mutants harboring IDE-insensitive p6 variants exhibit reduced virus replication capacity, a phenomenon that seems to depend on the presence of an X4-tropic Env. Furthermore, competing for IDE by exogenous insulin or inhibiting IDE by the highly specific inhibitor 6bK, also reduced virus replication. This effect could be specifically attributed to IDE since replication of HIV-1 variants coding for an IDE-insensitive p6 were inert towards IDE-inhibition. Our cumulative data support a model in which removal of p6 during viral entry is important for virus replication, at least in the case of X4 tropic HIV-1.

  7. Deletion of nardilysin prevents the development of steatohepatitis and liver fibrotic changes.

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    Shoko Ishizu-Higashi

    Full Text Available Nonalcoholic steatohepatitis (NASH is an inflammatory form of nonalcoholic fatty liver disease that progresses to liver cirrhosis. It is still unknown how only limited patients with fatty liver develop NASH. Tumor necrosis factor (TNF-α is one of the key molecules in initiating the vicious circle of inflammations. Nardilysin (N-arginine dibasic convertase; Nrd1, a zinc metalloendopeptidase of the M16 family, enhances ectodomain shedding of TNF-α, resulting in the activation of inflammatory responses. In this study, we aimed to examine the role of Nrd1 in the development of NASH. Nrd1+/+ and Nrd1-/- mice were fed a control choline-supplemented amino acid-defined (CSAA diet or a choline-deficient amino acid-defined (CDAA diet. Fatty deposits were accumulated in the livers of both Nrd1+/+ and Nrd1-/- mice by the administration of the CSAA or CDAA diets, although the amount of liver triglyceride in Nrd1-/- mice was lower than that in Nrd1+/+ mice. Serum alanine aminotransferase levels were increased in Nrd1+/+ mice but not in Nrd1-/- mice fed the CDAA diet. mRNA expression of inflammatory cytokines were decreased in Nrd1-/- mice than in Nrd1+/+ mice fed the CDAA diet. While TNF-α protein was detected in both Nrd1+/+ and Nrd1-/- mouse livers fed the CDAA diet, secretion of TNF-α in Nrd1-/- mice was significantly less than that in Nrd1+/+ mice, indicating the decreased TNF-α shedding in Nrd1-/- mouse liver. Notably, fibrotic changes of the liver, accompanied by the increase of fibrogenic markers, were observed in Nrd1+/+ mice but not in Nrd1-/- mice fed the CDAA diet. Similar to the CDAA diet, fibrotic changes were not observed in Nrd1-/- mice fed a high-fat diet. Thus, deletion of nardilysin prevents the development of diet-induced steatohepatitis and liver fibrogenesis. Nardilysin could be an attractive target for anti-inflammatory therapy against NASH.

  8. Novel prognostic markers in the serum of patients with castration-resistant prostate cancer derived from quantitative analysis of the pten conditional knockout mouse proteome. (United States)

    Kälin, Martin; Cima, Igor; Schiess, Ralph; Fankhauser, Niklaus; Powles, Tom; Wild, Peter; Templeton, Arnoud; Cerny, Thomas; Aebersold, Ruedi; Krek, Wilhelm; Gillessen, Silke


    Metastatic castration-resistant prostate cancer (mCRPC) is associated with a poor outcome. Prognostic information is useful and aids treatment decisions. However, current nomograms based on clinical parameters alone have weak prognostic accuracy. Therefore, the identification of new prognostic serum biomarkers could be useful. To assess if quantitative analysis of the phosphatase and tensin homolog (Pten) conditional knockout mouse proteome reveals significant prognostic biomarkers in mCRPC and to compare the accuracy of these biomarkers with known prognostic factors. Fifty-seven patients with mCRPC were evaluated retrospectively. Prognostic factors used in clinical nomograms were assessed from the records. New candidate biomarkers in patients' sera were derived using a cancer genetics-guided model we recently described, screening the murine Pten-dependent glycoproteome. Quantification in patients' sera was performed by either mass spectrometry-based targeted proteomics or enzyme-linked immunosorbent assays. Prognostic biomarkers for survival were identified based on Kaplan-Meier models. In a second step, random forest analysis was performed to identify a prognostic signature combined from the pooled data of known predictors and newly identified biomarkers. With univariate analysis, 13 new significant prognostic factors for survival in the sera of mCRPC patients were found with a Bonferroni-corrected level of significance <5%. Random forest analysis revealed a five-factor predictor (thrombospondin 1; C-reactive protein; poliovirus receptor-related 1; ephrin-A5; and membrane metallo-endopeptidase) with an accuracy of 96% and 94% for 12- and 24-mo survival, respectively. This means that, in our dataset, the error was reduced by 15% compared to using the Halabi et al. nomogram. The retrospective nature of the work and absence of a validating dataset is the major limitation of this work. Analysis of the serum proteome in mCRPC patients based on our Pten conditional