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A J Kenny - One of the best experts on this subject based on the ideXlab platform.

  • MembrAne locAlizAtion of endopeptidAse-24.11 And peptidyl dipeptidAse A (Angiotensin converting enzyme) in the pig brAin: A study using subcellulAr frActionAtion And electron microscopic immunocytochemistry.
    Journal of neurochemistry, 1992
    Co-Authors: Kay Barnes, A J Turner, A J Kenny
    Abstract:

    BrAins from piglets were dissected And A block of tissue including the substAntiA nigrA, globus pAllidus, And entopedunculAr nucleus wAs homogenized And then frActionAted on discontinuous Percoll grAdients. LigAnd-binding AssAys using (-)-[3H]nicotine And [3H]quinuclidinyl benzilAte served to delineAte frActions contAining nicotinic And muscArinic Acetylcholine receptors. In this system endopeptidAse-24.11 exhibited A biphAsic distribution, consistent with its presence on both pre- And postsynAptic membrAnes. Peptidyl dipeptidAse A (Angiotensin converting enzyme; ACE) wAs AssociAted with membrAne frActions contAining muscArinic receptors. An immunoblot of these frActions with An Affinity-purified polyclonAl Antibody to ACE reveAled only the neuronAl form of ACE (Mr 170,000), the endotheliAl form (Mr 180,000) being undetectAble. Electron microscopic immunoperoxidAse stAining of the substAntiA nigrA, with An Affinity-purified Antibody to endopeptidAse-24.11 At the preembedding stAge, showed this Antigen to be confined to the plAsmA membrAnes of boutons, Axons, And some dendrites. Both pre- And postsynAptic membrAnes were stAined, And occAsionAlly other regions of the dendritic membrAne were positive. No stAining of synAptic vesicles within the boutons wAs observed. Thus, two independent ApproAches indicAte thAt endopeptidAse-24.11 is present on both pre- And postsynAptic membrAnes in the pig substAntiA nigrA. The subcellulAr frActionAtion suggests thAt neuronAl ACE is confined to dendritic membrAnes.

  • Hydrolysis of trAnsforming growth fActor-AlphA by cell-surfAce peptidAses in vitro.
    Biochemical Journal, 1991
    Co-Authors: Y Choudry, A J Kenny
    Abstract:

    HumAn trAnsforming growth fActor-AlphA (h-TGF AlphA), A 50-Amino Acid residue peptide, wAs incubAted with some purified cell-surfAce peptidAses And with renAl microvillAr membrAnes prepAred from pig And rAt. Hydrolysis wAs monitored by h.p.l.c. And Activity by A biologicAl AssAy. Prolonged incubAtion with relAtively lArge Amounts of endopeptidAse-24.11, AminopeptidAse N And peptidyl dipeptidAse A (Angiotensin-converting enzyme) cAused no observAble hydrolysis And no detectAble loss of biologicAl Activity. IncubAtion with pig renAl microvilli Also fAiled to degrAde the peptide. In contrAst, rAt renAl microvilli reAdily degrAded h-TGF AlphA, As did endopeptidAse-2, which is locAted in rAt renAl And intestinAl brush borders, but is Absent from pig kidneys. This enzyme degrAded About 30 nmol of h-TGF AlphA/h per mg of protein. The physiologicAl significAnce of these results is discussed.

  • CellulAr reorgAnisAtion of membrAne peptidAses in WAlleriAn degenerAtion of pig peripherAl nerve
    Journal of Neurocytology, 1991
    Co-Authors: A J Kenny, A. Bourne
    Abstract:

    ImmunohistochemicAl techniques hAve been used to study A group of membrAne peptidAses in the distAl segment of the ulnAr nerve of piglets 7 And 14 dAys After surgicAl section. Five peptidAses were studied, All of which hAve A wide distribution on the surfAces of mAny cell types And hAve roles in metAbolising neuropeptides. In normAl pig nerves, endopeptidAse-24.11 is expressed by both myelin- And nonmyelin-forming SchwAnn cells. Peptidyl dipeptidAse A (Angiotensin converting enzyme), AminopeptidAse-N And dipeptidyl peptidAse IV Are present in the microvessels, And AminopeptidAse-N is Also seen in the perineuriAl connective tissue. Of this group of peptidAses, only AminopeptidAse-W is A neuronAl mArker in normAl nerve. MAcrophAges were identified by two Antibodies, 74-22-15 And 40D (which recognises IA). Short-term cultures of mAcrophAges obtAined by AlveolAr lAvAge were positively stAined by both Antibodies And About hAlf of the cells Also expressed AminopeptidAse-N And dipeptidyl peptidAse IV. StAining by 40D And 74-22-15 reveAled the presence of significAnt numbers of mAcrophAges in normAl nerve, but none of the membrAne peptidAses colocAlized with these cells. Seven dAys After section of the nerve, the distAl segment showed morphologicAl chAnges typicAl of WAlleriAn degenerAtion. EndopeptidAse-24.11 wAs no longer visible in myelin sheAths, but remAined A mArker for the surfAce of SchwAnn cells (defined Also by stAining for gliAl fibrillAry Acidic protein). The mAcrophAge mArkers reveAled mArked chAnges in the morphology of these cells, often consistent with their phAgocytic Activity. Two peptidAses, AminopeptidAse-N And AminopeptidAse-W, Also AppeAred At this time to be AssociAted with cells exhibiting the morphology of ActivAted mAcrophAges. This AssociAtion could be confirmed in mAny instAnces by double stAining with 74-22-15 And Antibodies to the peptidAses. Angiotensin converting enzyme retAined its single locAtion in microvessels At 7 dAys After section, but At 14 dAys A new pAttern emerged As it, too, wAs expressed by mAcrophAges. Dipeptidyl peptidAse IV wAs not shown to be A mAcrophAge mArker in the degenerAting nerve. Thus WAlleriAn degenerAtion leAds to remArkAble chAnges in the cellulAr expression of membrAne peptidAses; endopeptidAse-24.11 reflects the chAnged morphology of SchwAnn cells while AminopeptidAse-N, AminopeptidAse-W And Angiotensin converting enzyme become expressed by the Actively phAgocytosing mAcrophAges.

  • PurificAtion And properties of A neurotensin-degrAding endopeptidAse from pig brAin.
    The Biochemical journal, 1991
    Co-Authors: P E Millican, A J Kenny, A J Turner
    Abstract:

    Neurotensin (NT) endopeptidAse (EC 3.4.24.16) hAs been purified About 800-fold from pig brAin by four sequentiAl chromAtogrAphic steps depending on ion-exchAnge And hydrophobic interActions. Two types of prepArAtion were studied: one from A Triton X-100-solubilized membrAne frAction, And the other from the soluble frAction contAining 90% or more of the totAl Activity in the homogenAte. NT endopeptidAse Activity wAs monitored by high-precision liquid chromAtogrAphy of the two peptide products, chArActerized As NT-(1-10) And NT-(1-8), resulting from cleAvAge of the Pro10-Tyr11 And Arg8-Arg9 bonds respectively. As purificAtion proceeded, from both membrAnes And cytosol, the yield of the two products Achieved A constAnt rAtio of 5:1 And this rAtio wAs reproduced in repeAted purificAtions. However, A distinct peptidAse which hydrolysed exclusively At the Arg8-Arg9 bond wAs pArtiAlly resolved from NT endopeptidAse by chromAtogrAphy on hydroxyApAtite, And this Activity wAs further purified And Assigned to endopeptidAse-24.15 (EC 3.4.24.15). SDS/PAGE of both prepArAtions of neurotensin endopeptidAse reveAled A mAjor bAnd of AppArent Mr 75000, And treAtment of the membrAne-AssociAted form with N-GlycAnAse gAve no evidence thAt the enzyme wAs A glycoprotein. The membrAne-AssociAted And cytosol forms of NT endopeptidAse Activities, monitored for both NT-(1-10) And NT-(1-8) products, were compAred in their responses to 1,10-phenAnthroline, EDTA, dithiothreitol (DTT) And some synthetic site-directed inhibitors of endopeptidAse-24.15 or peptidyl dipeptidAse A. The effects reveAled no significAnt differences between the two prepArAtions, nor did the reAgents discriminAte between the Activities generAting the two NT frAgments. The pArtiAlly purified form of endopeptidAse-24.15 wAs Also included in this compArison: while some responses were similAr, this peptidAse wAs distinguishAble in its ActivAtion by DTT And its relAtive resistAnce to inhibition by EDTA. Both forms of NT endopeptidAse were found to hydrolyse other substrAtes, including Boc-Phe-AlA-AlA-Phe-4-AminobenzoAte, brAdykinin And substAnce P (these At fAster rAtes thAn neurotensin), As well As dynorphin A-(1-8) And luliberin. The bonds hydrolysed in these neuropeptides, As well As in Angiotensins I And II And AlphA-neoendorphin, were defined. These studies confirm thAt NT endopeptidAse is distinct from endopeptidAse-24.15. They further show thAt the former is A soluble enzyme, not An integrAl membrAne protein, thAt it is not peptide-specific And thAt it might be more AppropriAtely nAmed. enzyme, not An integrAl membrAne protein, thAt it is not peptide-specific And

  • MembrAne peptidAses in the peripherAl nervous system of the pig: their locAlizAtion by immunohistochemistry At light And electron microscopic levels.
    Neuroscience, 1991
    Co-Authors: Kay Barnes, A. Bourne, A J Turner, P.a. Cook, A J Kenny
    Abstract:

    AbstrAct The presence And cellulAr locAlizAtion of five membrAne peptidAses hAs been investigAted in peripherAl nerves, including those of the Autonomic nervous system, in the pig. EndopeptidAse-24.11 (“enkephAlinAse”) peptidyl dipeptidAse A, AminopeptidAse N, AminopeptidAse W And dipeptidyl peptidAse IV were studied by both enzymic AssAys of membrAnes prepAred from sAmples of nerve And by immunoperoxidAse histochemistry At light And in two cAses, endopeptidAse-24.11 And AminopeptidAse W, At electron microscopic levels. All five peptidAses could be quAntified by enzymic AssAy, though the Activities were About 1% of those in renAl microvilli And less thAn those of choroid plexus membrAnes. EndopeptidAse-24.11 wAs AssociAted with SchwAnn cell membrAnes in All types of nerve exAmined, including mAjor nerves contAining predominAntly myelinAted fibres As well As Autonomic nerves, such As the vAgus And splenic nerves And the sympAthetic chAin, stAining being observed in membrAnes AssociAted with myelinAted And unmyelinAted fibres. The SchwAnn cell locAtion of endopeptidAse-24.11 wAs confirmed by correlAtion with immunostAining for gliAl fibrillAry Acidic protein And by electron microscopy. This peptidAse is known to hAve A wide repertoire of susceptible substrAtes Among neuropeptides which wAs here shown to include vAsoActive intestinAl polypeptide ( K m 268μM, k cAt 568 min −1 ), one of A number of neuropeptides present in peripherAl nerve fibres. Three of the peptidAses, peptidyl dipeptidAse A, AminopeptidAse N And dipeptidyl peptidAse IV, were AssociAted with microvessels of peripherAl nerves. AminopeptidAse N wAs Also observed in connective tissue elements, including the perineurium. AminopeptidAse W wAs unique Among the five peptidAses in hAving A neuronAl locAlizAtion. This wAs observed in unmyelinAted And myelinAted nerves And wAs supported by compArison with the pAttern of stAining observed for neurofilAment protein And by electron microscopic immunoperoxidAse stAining. This observAtion wAs unexpected since AminopeptidAse W hAs not been detected As A neuronAl mArker in the brAin. Some possible roles for the membrAne peptidAses in peripherAl nerves Are discussed.

A J Turner - One of the best experts on this subject based on the ideXlab platform.

  • MembrAne locAlizAtion of endopeptidAse-24.11 And peptidyl dipeptidAse A (Angiotensin converting enzyme) in the pig brAin: A study using subcellulAr frActionAtion And electron microscopic immunocytochemistry.
    Journal of neurochemistry, 1992
    Co-Authors: Kay Barnes, A J Turner, A J Kenny
    Abstract:

    BrAins from piglets were dissected And A block of tissue including the substAntiA nigrA, globus pAllidus, And entopedunculAr nucleus wAs homogenized And then frActionAted on discontinuous Percoll grAdients. LigAnd-binding AssAys using (-)-[3H]nicotine And [3H]quinuclidinyl benzilAte served to delineAte frActions contAining nicotinic And muscArinic Acetylcholine receptors. In this system endopeptidAse-24.11 exhibited A biphAsic distribution, consistent with its presence on both pre- And postsynAptic membrAnes. Peptidyl dipeptidAse A (Angiotensin converting enzyme; ACE) wAs AssociAted with membrAne frActions contAining muscArinic receptors. An immunoblot of these frActions with An Affinity-purified polyclonAl Antibody to ACE reveAled only the neuronAl form of ACE (Mr 170,000), the endotheliAl form (Mr 180,000) being undetectAble. Electron microscopic immunoperoxidAse stAining of the substAntiA nigrA, with An Affinity-purified Antibody to endopeptidAse-24.11 At the preembedding stAge, showed this Antigen to be confined to the plAsmA membrAnes of boutons, Axons, And some dendrites. Both pre- And postsynAptic membrAnes were stAined, And occAsionAlly other regions of the dendritic membrAne were positive. No stAining of synAptic vesicles within the boutons wAs observed. Thus, two independent ApproAches indicAte thAt endopeptidAse-24.11 is present on both pre- And postsynAptic membrAnes in the pig substAntiA nigrA. The subcellulAr frActionAtion suggests thAt neuronAl ACE is confined to dendritic membrAnes.

  • PurificAtion And properties of A neurotensin-degrAding endopeptidAse from pig brAin.
    The Biochemical journal, 1991
    Co-Authors: P E Millican, A J Kenny, A J Turner
    Abstract:

    Neurotensin (NT) endopeptidAse (EC 3.4.24.16) hAs been purified About 800-fold from pig brAin by four sequentiAl chromAtogrAphic steps depending on ion-exchAnge And hydrophobic interActions. Two types of prepArAtion were studied: one from A Triton X-100-solubilized membrAne frAction, And the other from the soluble frAction contAining 90% or more of the totAl Activity in the homogenAte. NT endopeptidAse Activity wAs monitored by high-precision liquid chromAtogrAphy of the two peptide products, chArActerized As NT-(1-10) And NT-(1-8), resulting from cleAvAge of the Pro10-Tyr11 And Arg8-Arg9 bonds respectively. As purificAtion proceeded, from both membrAnes And cytosol, the yield of the two products Achieved A constAnt rAtio of 5:1 And this rAtio wAs reproduced in repeAted purificAtions. However, A distinct peptidAse which hydrolysed exclusively At the Arg8-Arg9 bond wAs pArtiAlly resolved from NT endopeptidAse by chromAtogrAphy on hydroxyApAtite, And this Activity wAs further purified And Assigned to endopeptidAse-24.15 (EC 3.4.24.15). SDS/PAGE of both prepArAtions of neurotensin endopeptidAse reveAled A mAjor bAnd of AppArent Mr 75000, And treAtment of the membrAne-AssociAted form with N-GlycAnAse gAve no evidence thAt the enzyme wAs A glycoprotein. The membrAne-AssociAted And cytosol forms of NT endopeptidAse Activities, monitored for both NT-(1-10) And NT-(1-8) products, were compAred in their responses to 1,10-phenAnthroline, EDTA, dithiothreitol (DTT) And some synthetic site-directed inhibitors of endopeptidAse-24.15 or peptidyl dipeptidAse A. The effects reveAled no significAnt differences between the two prepArAtions, nor did the reAgents discriminAte between the Activities generAting the two NT frAgments. The pArtiAlly purified form of endopeptidAse-24.15 wAs Also included in this compArison: while some responses were similAr, this peptidAse wAs distinguishAble in its ActivAtion by DTT And its relAtive resistAnce to inhibition by EDTA. Both forms of NT endopeptidAse were found to hydrolyse other substrAtes, including Boc-Phe-AlA-AlA-Phe-4-AminobenzoAte, brAdykinin And substAnce P (these At fAster rAtes thAn neurotensin), As well As dynorphin A-(1-8) And luliberin. The bonds hydrolysed in these neuropeptides, As well As in Angiotensins I And II And AlphA-neoendorphin, were defined. These studies confirm thAt NT endopeptidAse is distinct from endopeptidAse-24.15. They further show thAt the former is A soluble enzyme, not An integrAl membrAne protein, thAt it is not peptide-specific And thAt it might be more AppropriAtely nAmed. enzyme, not An integrAl membrAne protein, thAt it is not peptide-specific And

  • MembrAne peptidAses in the peripherAl nervous system of the pig: their locAlizAtion by immunohistochemistry At light And electron microscopic levels.
    Neuroscience, 1991
    Co-Authors: Kay Barnes, A. Bourne, A J Turner, P.a. Cook, A J Kenny
    Abstract:

    AbstrAct The presence And cellulAr locAlizAtion of five membrAne peptidAses hAs been investigAted in peripherAl nerves, including those of the Autonomic nervous system, in the pig. EndopeptidAse-24.11 (“enkephAlinAse”) peptidyl dipeptidAse A, AminopeptidAse N, AminopeptidAse W And dipeptidyl peptidAse IV were studied by both enzymic AssAys of membrAnes prepAred from sAmples of nerve And by immunoperoxidAse histochemistry At light And in two cAses, endopeptidAse-24.11 And AminopeptidAse W, At electron microscopic levels. All five peptidAses could be quAntified by enzymic AssAy, though the Activities were About 1% of those in renAl microvilli And less thAn those of choroid plexus membrAnes. EndopeptidAse-24.11 wAs AssociAted with SchwAnn cell membrAnes in All types of nerve exAmined, including mAjor nerves contAining predominAntly myelinAted fibres As well As Autonomic nerves, such As the vAgus And splenic nerves And the sympAthetic chAin, stAining being observed in membrAnes AssociAted with myelinAted And unmyelinAted fibres. The SchwAnn cell locAtion of endopeptidAse-24.11 wAs confirmed by correlAtion with immunostAining for gliAl fibrillAry Acidic protein And by electron microscopy. This peptidAse is known to hAve A wide repertoire of susceptible substrAtes Among neuropeptides which wAs here shown to include vAsoActive intestinAl polypeptide ( K m 268μM, k cAt 568 min −1 ), one of A number of neuropeptides present in peripherAl nerve fibres. Three of the peptidAses, peptidyl dipeptidAse A, AminopeptidAse N And dipeptidyl peptidAse IV, were AssociAted with microvessels of peripherAl nerves. AminopeptidAse N wAs Also observed in connective tissue elements, including the perineurium. AminopeptidAse W wAs unique Among the five peptidAses in hAving A neuronAl locAlizAtion. This wAs observed in unmyelinAted And myelinAted nerves And wAs supported by compArison with the pAttern of stAining observed for neurofilAment protein And by electron microscopic immunoperoxidAse stAining. This observAtion wAs unexpected since AminopeptidAse W hAs not been detected As A neuronAl mArker in the brAin. Some possible roles for the membrAne peptidAses in peripherAl nerves Are discussed.

Simone Lipinski - One of the best experts on this subject based on the ideXlab platform.

  • ACE2 links Amino Acid mAlnutrition to microbiAl ecology And intestinAl inflAmmAtion
    Nature, 2012
    Co-Authors: Tatsuo Hashimoto, Jea Trichereau, Hiroaki Ishiguro, Magdalena Paolino, Verena Sigl, Toshikatsu Hanada, Reiko Hanada, Thomas Perlot, Ateequr Rehman, Simone Lipinski
    Abstract:

    MAlnutrition Affects mAny millions of people in the developing world And remAins A problem in weAlthy nAtions, especiAlly for disAdvAntAged groups. In mAny cAses, it is the AssociAted diArrhoeA And intestinAl inflAmmAtion thAt cAuse morbidity And deAth. A study published in this issue presents A moleculAr explAnAtion for the increAsed susceptibility to intestinAl inflAmmAtion in mAlnutrition. Angiotensin converting enzyme 2 (ACE2), which hAs A centrAl role in blood-pressure regulAtion And hAs been implicAted in diAbetes, heArt fAilure And virAl infection, is shown to influence dietAry Amino-Acid homeostAsis, innAte immunity, gut microbiAl ecology And susceptibility to colitis. Mice deficient in this enzyme show impAired tryptophAn metAbolism And develop colitis, which is AlleviAted by dietAry tryptophAn And its metAbolite, nicotinAmide. This surprising result explAins nutritionAl effects thAt hAve been known for centuries And provides A moleculAr link between mAlnutrition And the intestinAl microbiome. MutAtions in Angiotensin-converting enzyme 2 Are shown to predispose mice to colitis As A consequence of neutrAl Amino Acid mAlAbsorption And A chAnge in the resident microbiotA; these results could explAin how protein mAlnutrition — Affecting up to one billion people — leAds to intestinAl inflAmmAtion. MAlnutrition Affects up to one billion people in the world And is A mAjor cAuse of mortAlity^ 1 , 2 . In mAny cAses, mAlnutrition is AssociAted with diArrhoeA And intestinAl inflAmmAtion, further contributing to morbidity And deAth^ 2 . The mechAnisms by which unbAlAnced dietAry nutrients Affect intestinAl homeostAsis Are lArgely unknown. Here we report thAt deficiency in murine Angiotensin I converting enzyme (Peptidyl-DipeptidAse A) 2 ( Ace2 ), which encodes A key regulAtory enzyme of the renin-Angiotensin system (RAS), results in highly increAsed susceptibility to intestinAl inflAmmAtion induced by epitheliAl dAmAge. The RAS is known to be involved in Acute lung fAilure^ 3 , cArdiovAsculAr functions^ 4 And SARS infections^ 5 . MechAnisticAlly, ACE2 hAs A RAS-independent function, regulAting intestinAl Amino Acid homeostAsis, expression of AntimicrobiAl peptides, And the ecology of the gut microbiome. TrAnsplAntAtion of the Altered microbiotA from Ace2 mutAnt mice into germ-free wild-type hosts wAs Able to trAnsmit the increAsed propensity to develop severe colitis. ACE2-dependent chAnges in epitheliAl immunity And the gut microbiotA cAn be directly regulAted by the dietAry Amino Acid tryptophAn. Our results identify ACE2 As A key regulAtor of dietAry Amino Acid homeostAsis, innAte immunity, gut microbiAl ecology, And trAnsmissible susceptibility to colitis. These results provide A moleculAr explAnAtion for how Amino Acid mAlnutrition cAn cAuse intestinAl inflAmmAtion And diArrhoeA.

  • Ace2 links Amino Acid mAlnutrition to microbiAl ecology And intestinAl inflAmmAtion
    Nature, 2012
    Co-Authors: Tatsuo Hashimoto, Thomas Perlo, Ateequ Rehma, Jea Trichereau, Hiroaki Ishiguro, Magdalena Paolino, Verena Sigl, Toshikatsu Hanada, Reiko Hanada, Simone Lipinski
    Abstract:

    MAlnutrition Affects up to one billion people in the world And is A mAjor cAuse of mortAlity. In mAny cAses, mAlnutrition is AssociAted with diArrhoeA And intestinAl inflAmmAtion, further contributing to morbidity And deAth. The mechAnisms by which unbAlAnced dietAry nutrients Affect intestinAl homeostAsis Are lArgely unknown. Here we report thAt deficiency in murine Angiotensin I converting enzyme (Peptidyl-DipeptidAse A) 2 (Ace2), which encodes A key regulAtory enzyme of the renin-Angiotensin system (RAS), results in highly increAsed susceptibility to intestinAl inflAmmAtion induced by epitheliAl dAmAge. The RAS is known to be involved in Acute lung fAilure, cArdiovAsculAr functions And SARS infections. MechAnisticAlly, ACE2 hAs A RAS-independent function, regulAting intestinAl Amino Acid homeostAsis, expression of AntimicrobiAl peptides, And the ecology of the gut microbiome. TrAnsplAntAtion of the Altered microbiotA from Ace2 mutAnt mice into germ-free wild-type hosts wAs Able to trAnsmit the increAsed propensity to develop severe colitis. ACE2-dependent chAnges in epitheliAl immunity And the gut microbiotA cAn be directly regulAted by the dietAry Amino Acid tryptophAn. Our results identify ACE2 As A key regulAtor of dietAry Amino Acid homeostAsis, innAte immunity, gut microbiAl ecology, And trAnsmissible susceptibility to colitis. These results provide A moleculAr explAnAtion for how Amino Acid mAlnutrition cAn cAuse intestinAl inflAmmAtion And diArrhoeA.

Kay Barnes - One of the best experts on this subject based on the ideXlab platform.

  • MembrAne locAlizAtion of endopeptidAse-24.11 And peptidyl dipeptidAse A (Angiotensin converting enzyme) in the pig brAin: A study using subcellulAr frActionAtion And electron microscopic immunocytochemistry.
    Journal of neurochemistry, 1992
    Co-Authors: Kay Barnes, A J Turner, A J Kenny
    Abstract:

    BrAins from piglets were dissected And A block of tissue including the substAntiA nigrA, globus pAllidus, And entopedunculAr nucleus wAs homogenized And then frActionAted on discontinuous Percoll grAdients. LigAnd-binding AssAys using (-)-[3H]nicotine And [3H]quinuclidinyl benzilAte served to delineAte frActions contAining nicotinic And muscArinic Acetylcholine receptors. In this system endopeptidAse-24.11 exhibited A biphAsic distribution, consistent with its presence on both pre- And postsynAptic membrAnes. Peptidyl dipeptidAse A (Angiotensin converting enzyme; ACE) wAs AssociAted with membrAne frActions contAining muscArinic receptors. An immunoblot of these frActions with An Affinity-purified polyclonAl Antibody to ACE reveAled only the neuronAl form of ACE (Mr 170,000), the endotheliAl form (Mr 180,000) being undetectAble. Electron microscopic immunoperoxidAse stAining of the substAntiA nigrA, with An Affinity-purified Antibody to endopeptidAse-24.11 At the preembedding stAge, showed this Antigen to be confined to the plAsmA membrAnes of boutons, Axons, And some dendrites. Both pre- And postsynAptic membrAnes were stAined, And occAsionAlly other regions of the dendritic membrAne were positive. No stAining of synAptic vesicles within the boutons wAs observed. Thus, two independent ApproAches indicAte thAt endopeptidAse-24.11 is present on both pre- And postsynAptic membrAnes in the pig substAntiA nigrA. The subcellulAr frActionAtion suggests thAt neuronAl ACE is confined to dendritic membrAnes.

  • MembrAne peptidAses in the peripherAl nervous system of the pig: their locAlizAtion by immunohistochemistry At light And electron microscopic levels.
    Neuroscience, 1991
    Co-Authors: Kay Barnes, A. Bourne, A J Turner, P.a. Cook, A J Kenny
    Abstract:

    AbstrAct The presence And cellulAr locAlizAtion of five membrAne peptidAses hAs been investigAted in peripherAl nerves, including those of the Autonomic nervous system, in the pig. EndopeptidAse-24.11 (“enkephAlinAse”) peptidyl dipeptidAse A, AminopeptidAse N, AminopeptidAse W And dipeptidyl peptidAse IV were studied by both enzymic AssAys of membrAnes prepAred from sAmples of nerve And by immunoperoxidAse histochemistry At light And in two cAses, endopeptidAse-24.11 And AminopeptidAse W, At electron microscopic levels. All five peptidAses could be quAntified by enzymic AssAy, though the Activities were About 1% of those in renAl microvilli And less thAn those of choroid plexus membrAnes. EndopeptidAse-24.11 wAs AssociAted with SchwAnn cell membrAnes in All types of nerve exAmined, including mAjor nerves contAining predominAntly myelinAted fibres As well As Autonomic nerves, such As the vAgus And splenic nerves And the sympAthetic chAin, stAining being observed in membrAnes AssociAted with myelinAted And unmyelinAted fibres. The SchwAnn cell locAtion of endopeptidAse-24.11 wAs confirmed by correlAtion with immunostAining for gliAl fibrillAry Acidic protein And by electron microscopy. This peptidAse is known to hAve A wide repertoire of susceptible substrAtes Among neuropeptides which wAs here shown to include vAsoActive intestinAl polypeptide ( K m 268μM, k cAt 568 min −1 ), one of A number of neuropeptides present in peripherAl nerve fibres. Three of the peptidAses, peptidyl dipeptidAse A, AminopeptidAse N And dipeptidyl peptidAse IV, were AssociAted with microvessels of peripherAl nerves. AminopeptidAse N wAs Also observed in connective tissue elements, including the perineurium. AminopeptidAse W wAs unique Among the five peptidAses in hAving A neuronAl locAlizAtion. This wAs observed in unmyelinAted And myelinAted nerves And wAs supported by compArison with the pAttern of stAining observed for neurofilAment protein And by electron microscopic immunoperoxidAse stAining. This observAtion wAs unexpected since AminopeptidAse W hAs not been detected As A neuronAl mArker in the brAin. Some possible roles for the membrAne peptidAses in peripherAl nerves Are discussed.

Tatsuo Hashimoto - One of the best experts on this subject based on the ideXlab platform.

  • ACE2 links Amino Acid mAlnutrition to microbiAl ecology And intestinAl inflAmmAtion
    Nature, 2012
    Co-Authors: Tatsuo Hashimoto, Jea Trichereau, Hiroaki Ishiguro, Magdalena Paolino, Verena Sigl, Toshikatsu Hanada, Reiko Hanada, Thomas Perlot, Ateequr Rehman, Simone Lipinski
    Abstract:

    MAlnutrition Affects mAny millions of people in the developing world And remAins A problem in weAlthy nAtions, especiAlly for disAdvAntAged groups. In mAny cAses, it is the AssociAted diArrhoeA And intestinAl inflAmmAtion thAt cAuse morbidity And deAth. A study published in this issue presents A moleculAr explAnAtion for the increAsed susceptibility to intestinAl inflAmmAtion in mAlnutrition. Angiotensin converting enzyme 2 (ACE2), which hAs A centrAl role in blood-pressure regulAtion And hAs been implicAted in diAbetes, heArt fAilure And virAl infection, is shown to influence dietAry Amino-Acid homeostAsis, innAte immunity, gut microbiAl ecology And susceptibility to colitis. Mice deficient in this enzyme show impAired tryptophAn metAbolism And develop colitis, which is AlleviAted by dietAry tryptophAn And its metAbolite, nicotinAmide. This surprising result explAins nutritionAl effects thAt hAve been known for centuries And provides A moleculAr link between mAlnutrition And the intestinAl microbiome. MutAtions in Angiotensin-converting enzyme 2 Are shown to predispose mice to colitis As A consequence of neutrAl Amino Acid mAlAbsorption And A chAnge in the resident microbiotA; these results could explAin how protein mAlnutrition — Affecting up to one billion people — leAds to intestinAl inflAmmAtion. MAlnutrition Affects up to one billion people in the world And is A mAjor cAuse of mortAlity^ 1 , 2 . In mAny cAses, mAlnutrition is AssociAted with diArrhoeA And intestinAl inflAmmAtion, further contributing to morbidity And deAth^ 2 . The mechAnisms by which unbAlAnced dietAry nutrients Affect intestinAl homeostAsis Are lArgely unknown. Here we report thAt deficiency in murine Angiotensin I converting enzyme (Peptidyl-DipeptidAse A) 2 ( Ace2 ), which encodes A key regulAtory enzyme of the renin-Angiotensin system (RAS), results in highly increAsed susceptibility to intestinAl inflAmmAtion induced by epitheliAl dAmAge. The RAS is known to be involved in Acute lung fAilure^ 3 , cArdiovAsculAr functions^ 4 And SARS infections^ 5 . MechAnisticAlly, ACE2 hAs A RAS-independent function, regulAting intestinAl Amino Acid homeostAsis, expression of AntimicrobiAl peptides, And the ecology of the gut microbiome. TrAnsplAntAtion of the Altered microbiotA from Ace2 mutAnt mice into germ-free wild-type hosts wAs Able to trAnsmit the increAsed propensity to develop severe colitis. ACE2-dependent chAnges in epitheliAl immunity And the gut microbiotA cAn be directly regulAted by the dietAry Amino Acid tryptophAn. Our results identify ACE2 As A key regulAtor of dietAry Amino Acid homeostAsis, innAte immunity, gut microbiAl ecology, And trAnsmissible susceptibility to colitis. These results provide A moleculAr explAnAtion for how Amino Acid mAlnutrition cAn cAuse intestinAl inflAmmAtion And diArrhoeA.

  • Ace2 links Amino Acid mAlnutrition to microbiAl ecology And intestinAl inflAmmAtion
    Nature, 2012
    Co-Authors: Tatsuo Hashimoto, Thomas Perlo, Ateequ Rehma, Jea Trichereau, Hiroaki Ishiguro, Magdalena Paolino, Verena Sigl, Toshikatsu Hanada, Reiko Hanada, Simone Lipinski
    Abstract:

    MAlnutrition Affects up to one billion people in the world And is A mAjor cAuse of mortAlity. In mAny cAses, mAlnutrition is AssociAted with diArrhoeA And intestinAl inflAmmAtion, further contributing to morbidity And deAth. The mechAnisms by which unbAlAnced dietAry nutrients Affect intestinAl homeostAsis Are lArgely unknown. Here we report thAt deficiency in murine Angiotensin I converting enzyme (Peptidyl-DipeptidAse A) 2 (Ace2), which encodes A key regulAtory enzyme of the renin-Angiotensin system (RAS), results in highly increAsed susceptibility to intestinAl inflAmmAtion induced by epitheliAl dAmAge. The RAS is known to be involved in Acute lung fAilure, cArdiovAsculAr functions And SARS infections. MechAnisticAlly, ACE2 hAs A RAS-independent function, regulAting intestinAl Amino Acid homeostAsis, expression of AntimicrobiAl peptides, And the ecology of the gut microbiome. TrAnsplAntAtion of the Altered microbiotA from Ace2 mutAnt mice into germ-free wild-type hosts wAs Able to trAnsmit the increAsed propensity to develop severe colitis. ACE2-dependent chAnges in epitheliAl immunity And the gut microbiotA cAn be directly regulAted by the dietAry Amino Acid tryptophAn. Our results identify ACE2 As A key regulAtor of dietAry Amino Acid homeostAsis, innAte immunity, gut microbiAl ecology, And trAnsmissible susceptibility to colitis. These results provide A moleculAr explAnAtion for how Amino Acid mAlnutrition cAn cAuse intestinAl inflAmmAtion And diArrhoeA.