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Lakritz JR, Yalamanchili S, Polydefkis MJ, Miller AD, McGrath MS, Williams KC, Burdo TH. An oral form of methylglyoxal-bis-guanylhydrazone reduces monocyte activation and traffic to the dorsal root ganglia in a primate model of HIV-peripheral neuropathy. J Neurovirol 2017; 23:568-576. [PMID: 28462488 DOI: 10.1007/s13365-017-0529-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 04/04/2017] [Indexed: 01/18/2023]
Abstract
Peripheral neuropathy (PN) is a major comorbidity of HIV infection that is caused in part by chronic immune activation. HIV-PN is associated with infiltration of monocytes/macrophages to the dorsal root ganglia (DRG) causing neuronal loss and formation of Nageotte nodules. Here, we used an oral form of methylglyoxal-bis-guanylhydrazone (MGBG), a polyamine biosynthesis inhibitor, to specifically reduce activation of myeloid cells. MGBG is selectively taken up by monocyte/macrophages in vitro and inhibits HIV p24 expression and DNA viral integration in macrophages. Here, MGBG was administered to nine SIV-infected, CD8-depleted rhesus macaques at 21 days post-infection (dpi). An additional nine SIV-infected, CD8-depleted rhesus macaques were used as untreated controls. Cell traffic to tissues was measured by in vivo BrdU pulse labeling. MGBG treatment significantly diminished DRG histopathology and reduced the number of CD68+ and CD163+ macrophages in DRG tissue. The number of recently trafficked BrdU+ cells in the DRG was significantly reduced with MGBG treatment. Despite diminished DRG pathology, intraepidermal nerve fiber density (IENFD) did not recover after treatment with MGBG. These data suggest that MGBG alleviated DRG pathology and inflammation.
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Affiliation(s)
| | | | | | - Andrew D Miller
- Department of Biomedical Sciences, Section of Anatomic Pathology, Cornell University College of Veterinary Medicine, Ithaca, NY, USA
| | - Michael S McGrath
- Departments of Laboratory Medicine, Medicine and Pathology, University of California at San Franscisco, San Francisco, CA, USA
| | | | - Tricia H Burdo
- Department of Neuroscience, Temple University School of Medicine, 3500 North Broad Street, MERB 755, Philadelphia, PA, 19140, USA.
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Nowicki M, Kosacka J, Brossmer R, Spanel-Borowski K, Borlak J. The myelin-associated glycoprotein inhibitor BENZ induces outgrowth and survival of rat dorsal root ganglion cell cultures. J Neurosci Res 2008; 85:3053-63. [PMID: 17722062 DOI: 10.1002/jnr.21422] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The novel myelin-associated glycoprotein (MAG) inhibitor BENZ binds to the N-acetylneuraminic acid (Neu5Ac) portion of the N-terminal Ig-like domain of MAG. Treatment of rat dorsal root ganglion (DRG) cell cultures with BENZ-induced outgrowth of neurofilament 200-positive neurites improved survival of neurons and increased the number of GFAP-positive cells, as determined by fluorescence and confocal laser microscopy and by Western immunoblotting. Furthermore, treatment of DRG cell cultures with BENZ repressed gene and protein expression of the small GTPase RhoA but induced expression of Rho GTP-activating proteins 5 and 24, likely to counteract protein kinase A activity. Specifically, expression of inhibitors of neurite outgrowth, for example, Rock2 and PAK4, was repressed, but cofilin 1, a promoter of axonal growth, was induced. We propose that the MAG inhibitor BENZ abrogates the RhoA-ROCK-cofilin pathway to promote neurite outgrowth. Our findings require confirmation by in vivo animal studies.
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Affiliation(s)
- Marcin Nowicki
- University of Leipzig, Institute of Anatomy, Leipzig, Germany
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3
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Méchaly I, Bourane S, Piquemal D, Al-Jumaily M, Ventéo S, Puech S, Scamps F, Valmier J, Carroll P. Gene profiling during development and after a peripheral nerve traumatism reveals genes specifically induced by injury in dorsal root ganglia. Mol Cell Neurosci 2006; 32:217-29. [PMID: 16769221 DOI: 10.1016/j.mcn.2006.04.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Revised: 04/03/2006] [Accepted: 04/11/2006] [Indexed: 12/22/2022] Open
Abstract
In order to shed light on transcriptional networks involved in adult peripheral nerve repair program, we propose for the first time an organization of the transcriptional dynamics of the mouse dorsal root ganglia (DRG) following a sciatic nerve lesion. This was done by a non-hierarchical bioinformatical clustering of four Serial Analysis of Gene Expression libraries performed on DRG at embryonic day E13, neonatal day P0, adult and adult 3 days post-sciatic nerve section. Grouping genes according to their expression profiles shows that a combination of down-regulation of genes expressed at the adult stages, re-expression of embryonic genes and induction of a set of de novo genes takes place in injured neurons. Focusing on this latter event highlights Ddit3, Timm8b and Oazin as potential new injury-induced molecular actors involved in a stress response pathway. Their association with the traumatic state was confirmed by real-time PCR and in situ hybridization investigations. Clustering analysis allows us to distinguish developmental re-programming events from nerve-injury-induced processes and thus provides a basis for molecular understanding of transcriptional alterations taking place in the DRG after a sciatic nerve lesion.
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Affiliation(s)
- Ilana Méchaly
- I.N.S.E.R.M. U583, Institut des Neurosciences de Montpellier-Hôpital St Eloi. 80, rue Augustin Fliche. BP 74103. 34091 Montpellier cedex 5, France.
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4
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Schreiber RC, Boeshore KL, Laube G, Veh RW, Zigmond RE. Polyamines increase in sympathetic neurons and non-neuronal cells after axotomy and enhance neurite outgrowth in nerve growth factor-primed PC12 cells. Neuroscience 2005; 128:741-9. [PMID: 15464282 DOI: 10.1016/j.neuroscience.2004.07.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2004] [Indexed: 11/22/2022]
Abstract
Following axonal damage, sympathetic neurons are capable of regenerating and reinnervating their target tissues. Some years ago exogenous administration of polyamines was shown to enhance this regeneration. Recently, it was found that axonal injury leads to a dramatic up-regulation of the expression of arginase I in sympathetic neurons. This enzyme catalyzes the conversion of arginine to ornithine, which can subsequently be converted to the diamine putrescine and, ultimately, to the polyamines spermidine and spermine. In the present study, using an antiserum that reacts with both spermidine and spermine, we have found an increase in polyamine levels in both neurons and non-neuronal cells in the superior cervical ganglion 2 and 5 days following transection of the ganglion's postganglionic trunks. Using PC12 cells primed with nerve growth factor and then stripped off the culture dish and replated as a model system for axotomized sympathetic neurons, we found that spermidine treatment, with or without nerve growth factor, resulted in an increased percentage of cells with a neurite whose length was at least twice the diameter of the neuron's cell body. These increases could be seen within 48 h and were still evident after 8 days. Together, these data support the possibility that endogenous polyamines are involved in the normal regeneration which occurs following sympathetic axonal damage.
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Affiliation(s)
- R C Schreiber
- Department of Neurosciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-4975, USA
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5
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Oble DA, Burton L, Maxwell K, Hassard T, Nathaniel EJH. A comparison of thyroxine- and polyamine-mediated enhancement of rat facial nerve regeneration. Exp Neurol 2004; 189:105-11. [PMID: 15296840 DOI: 10.1016/j.expneurol.2004.05.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2004] [Revised: 05/07/2004] [Accepted: 05/17/2004] [Indexed: 11/18/2022]
Abstract
Thyroid hormones and spermidine, a motor neuron trophic polyamine (PA), have been shown to enhance peripheral motor nerve regeneration; however, the mechanism by which these treatment modalities exert their effect is unknown. Similarities in treatment outcome suggest that these molecules may be working via a common mechanism. Such an explanation is plausible since thyroid hormone is a potent inducer of ornithine decarboxylase (ODC), which is the rate-limiting enzyme involved in polyamine synthesis. This study was designed to morphologically evaluate the effects of exogenous thyroxine and spermidine on the regeneration of the rat facial nerve. Myelinated fiber density, axonal size, and degree of myelination were assayed by light and electron microscopy 21 days following facial nerve crush. Strikingly, the two treatment modalities had identical effects on all parameters tested. Each significantly enhanced the density of myelinated axons in regenerating nerves relative to the vehicle control. In addition, relative to the control treatment, both thyroxine and spermidine significantly increased the cross-sectional area of regenerating axons (P < 0.05). Interestingly, neither of the drug treatments had any effect on remyelination at the position where this parameter was analyzed. The concurrent administration of both thyroxine and spermidine did not synergistically enhance motor neuron regeneration. These data support the hypothesis that thyroxine and spermidine enhance neural regeneration by a common mechanism.
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Affiliation(s)
- Darryl A Oble
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada R3E 0W3.
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Abstract
Injury to the adult mammalian central nervous system (CNS) often results in permanent loss of sensory and motor function. This is due to the failure of injured axons to regenerate. The inhibitory nature of the CNS can be attributed to several factors, including formation of the glial scar, the presence of several molecules, associated with myelin, which inhibit axonal regrowth, and the intrinsic growth state of these neurons. Encouraging regeneration in the adult mammalian CNS therefore will require targeting one or all of these factors following injury. Here we illustrate recent work from our laboratory that identifies some of the signalling components involved in modulation of the intrinsic growth state of adult neurons. When activated, these signalling pathways can induce axonal regeneration in the presence of the myelin-associated inhibitors both in vitro and in vivo.
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Affiliation(s)
- Tim Spencer
- Department of Biological Sciences, Hunter College, The City University of New York, NY 10021, USA
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7
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Abstract
Axon growth inhibitors associated with myelin and the glial scar contribute to the failure of axon regeneration in the injured adult mammalian central nervous system (CNS). A number of these inhibitors, their receptors, and signaling pathways have been identified. These inhibitors can now be neutralized by a variety of approaches that point to the possibility of developing new therapeutic strategies to stimulate regeneration after spinal cord injury.
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Affiliation(s)
- Samuel David
- Centre for Research in Neuroscience, McGill University Health Centre, Montreal General Hospital Research Institute, 1650 Cedar Avenue, Montreal, Quebec, Canada, H3G 1A4.
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Palacios J, Sepúlveda MR, Salvador JM, Mata AM. Effect of spermine on the activity of synaptosomal plasma membrane Ca(2+)-ATPase reconstituted in neutral or acidic phospholipids. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1611:197-203. [PMID: 12659961 DOI: 10.1016/s0005-2736(03)00057-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The activity of purified plasma membrane Ca(2+)-ATPase (PMCA) from pig brain was inhibited by spermine (a naturally occurring and highly abundant polycation in brain). The level of inhibition was dependent on the phospholipid used for reconstitution as well as on the intact or truncated state of the enzyme. An IC(50) value of 12.5 mM spermine was obtained for both, the intact protein plus calmodulin and the trypsin-digested protein, reconstituted in phosphatidylcholine (PC). In the absence of calmodulin the intact Ca(2+)-ATPase gave an IC(50) of 27 mM. This form was more sensitive to spermine inhibition when it was reconstituted with phosphatidylserine (PS), showing an IC(50) value of 2.5 mM spermine. However, the truncated form was less responsive to spermine inhibition, having an IC(50) value of 12.5 mM. Spermine has no effect on the affinity of the PMCA for Ca(2+) or ATP, but its effect on the protein is pH-dependent. It is suggested that spermine could bind to negatively charged residues on the ATPase with different accessibility, depending on the structural rearrangement of the protein. Further, when the protein is reconstituted in PS, spermine also binds to the lipid.
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Affiliation(s)
- Javier Palacios
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Ciencias, Universidad de Extremadura, 06071 Badajoz, Spain
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Cai D, Deng K, Mellado W, Lee J, Ratan RR, Filbin MT. Arginase I and polyamines act downstream from cyclic AMP in overcoming inhibition of axonal growth MAG and myelin in vitro. Neuron 2002; 35:711-9. [PMID: 12194870 DOI: 10.1016/s0896-6273(02)00826-7] [Citation(s) in RCA: 253] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Elevation of cAMP can overcome myelin inhibitors to encourage regeneration of the CNS. We show that a consequence of elevated cAMP is the synthesis of polyamines, resulting from an up-regulation of Arginase I, a key enzyme in their synthesis. Inhibiting polyamine synthesis blocks the cAMP effect on regeneration. Either over-expression of Arginase I or exogenous polyamines can overcome inhibition by MAG and by myelin in general. While MAG/myelin support the growth of young DRG neurons, they become inhibitory as DRGs mature. Endogenous Arginase I levels are high in young DRGs but drop spontaneously at an age that coincides with the switch from promotion to inhibition by MAG/myelin. Over-expressing Arginase I in maturing DRGs blocks that switch. Arginase I and polyamines are more specific targets than cAMP for intervention to encourage regeneration after CNS injury.
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Affiliation(s)
- Dongming Cai
- Biology Department, Hunter College, City University of New York, 695 Park Avenue, New York, NY 10024, USA
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10
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Cayre M, Malaterre J, Strambi C, Charpin P, Ternaux JP, Strambi A. Short- and long-chain natural polyamines play specific roles in adult cricket neuroblast proliferation and neuron differentiation in vitro. JOURNAL OF NEUROBIOLOGY 2001; 48:315-24. [PMID: 11500844 DOI: 10.1002/neu.1060] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the house cricket (Acheta domesticus) mushroom bodies, neurogenesis still occurs during adulthood. Using in vitro approaches, the respective roles of natural polyamines in neurogenesis were examined. Mushroom body neuroblast proliferation was assayed in organotypic culture using 5-bromo, 2'-deoxyuridine labeling. The number of labeled cells was significantly increased when putrescine was added to culture medium, whereas spermidine and spermine supplementation did not alter cell proliferation. Conversely, in vitro morphometric studies on mushroom body neurons cultured in a defined medium showed that putrescine addition failed to alter any morphological character of these interneurons, whereas addition of the long-chain polyamines, spermidine and spermine, stimulated neuron differentiation. These two polyamines significantly increased total neurite length; moreover, spermidine-treated cells exhibited more branches than the controls. The present data demonstrate that putrescine has a mitogenic effect on mushroom body neuronal precursors, and that spermidine and spermine, which failed to induce neuroblast proliferation, act on neuronal differentiation, inducing neurite outgrowth. Our results indicate that short- and long-chain polyamines play specific roles during neurogenesis, and provide a basis for further studies on neuronal precursor proliferation and differentiation.
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Affiliation(s)
- M Cayre
- Laboratoire de Neurobiologie, CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille cedex 20, France.
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11
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Yatin SM, Yatin M, Varadarajan S, Ain KB, Butterfield DA. Role of spermine in amyloid beta-peptide-associated free radical-induced neurotoxicity. J Neurosci Res 2001; 63:395-401. [PMID: 11223914 DOI: 10.1002/1097-4547(20010301)63:5<395::aid-jnr1034>3.0.co;2-q] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The polyamines, relatively low-molecular-weight aliphatic compounds, are the main inducers of eukaryotic cell growth and proliferation. Although polyamine requirements for cell growth are well defined, their role is still enigmatic. We have previously reported that amyloid beta-peptide (A beta), the main constituent of senile plaques in Alzheimer's disease (AD) brain, is toxic to neurons through a free radical-dependent oxidative stress mechanism and that A beta(1--42), the principal form of A beta in AD brain, causes an increase in polyamine metabolism manifested by up-regulated polyamine uptake and increased ornithine decarboxylase (ODC) activity. Both effects were prevented by the free radical scavenger vitamin E. Spermine has been reported to function directly as a free radical scavenger. In the current study, we aimed to address whether up-regulation of polyamine metabolism is a defense against, or a result of, A beta-induced oxidative stress by investigating the capability of spermine to quench A beta-associated free radicals in solution and to assert a protective function of spermine in neuronal culture against A beta. Pretreatment of cultured neurons with spermine prior to A beta exposure failed to prevent A beta-induced cell death. Indeed, A beta plus spermine added to cultured neurons was even more neurotoxic than either agent alone. Additionally, inhibition of the polyamine synthesis by difluoromethylornithine (DFMO) did not protect cells from A beta-induced free radical toxicity, and stimulation of the synthesis of putrescine and spermine by the aminopropyltransferase inhibitor S-adenosyl-1,8-diamino-thiooctane (AdoDATO), rather, further enhanced A beta-induced toxicity. Although spermine is capable of scavenging free radicals generated by A beta in solution as measured by electron paramagnetic resonance (EPR) spectroscopy, the up-regulated transport of exogenously added spermine together with A beta may lead to overaccumulation of a cellular spermine pool, with resulting enhanced neurotoxicity.
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Affiliation(s)
- S M Yatin
- Department of Chemistry and Center of Membrane Sciences, University of Kentucky, Lexington, 40506-0055, USA
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Giménez-Llort L, Martínez E, Camón L, de Vera N. Long-term effects of status epilepticus induced by kainic acid on hippocampal polyamines. Neuroreport 1998; 9:937-41. [PMID: 9579694 DOI: 10.1097/00001756-199803300-00032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Putrescine has been suggested to have an inhibitory effect on the excitability of the central nervous system. In the present study we found that 2 and 3 weeks after status epilepticus induced by kainic acid, rats had increased concentrations of putrescine (3- and 1.7-fold, respectively) and spermidine (1.6- and 1.4-fold, respectively) in the hippocampus. These animals exhibited a higher susceptibility to pentylentetrazol than the saline group. In addition, several hours after the pentylentetrazol injection, the concentration of putrescine and spermidine increased again in the brain and also in the plasma. In conclusion, increased hippocampal putrescine and spermidine concentrations seem to be linked with a lower threshold of excitability.
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Affiliation(s)
- L Giménez-Llort
- Department of Pharmacology and Toxicology, Institut d'Investigacions Biomèdiques de Barcelona, CSIC, Spain
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14
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Løvaas E. Antioxidative and metal-chelating effects of polyamines. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 1996; 38:119-49. [PMID: 8895807 DOI: 10.1016/s1054-3589(08)60982-5] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- E Løvaas
- Norweigian College of Fishery Science, University of Tromsø, Norway
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15
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Hirata H, Hibasami H, Hineno T, Shi D, Morita A, Inada H, Fujisawa K, Nakashima K, Ogihara Y. Role of ornithine decarboxylase in proliferation of Schwann cells during Wallerian degeneration and its enhancement by nerve expansion. Muscle Nerve 1995; 18:1341-3. [PMID: 7565936 DOI: 10.1002/mus.880181121] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- H Hirata
- Department of Orthopedic Surgery, Faculty of Medicine, Mie University, Japan
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Abstract
Despite considerable evidence implicating polyamines in CNS function, little is known about the status of the polyamine system in normal or abnormal human brain. We measured the levels of the polyamines spermidine, spermine and their precursor putrescine, in cortical and subcortical areas of 12 patients with Alzheimer's disease (AD). As compared with the controls, mean levels of spermidine were markedly and significantly increased (70%) whereas putrescine levels were decreased (28%) in temporal cortex of the AD patients. No other statistically significant changes were observed with the exception of a mean 35% reduction in spermine concentration in occipital cortex. In view of the modulatory effects of polyamines on calcium flux and glutamate receptor function, our data suggest that abnormal polyamine system activity may be involved in the neurodegenerative processes occurring in brain of patients with AD.
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Affiliation(s)
- L D Morrison
- Human Neurochemical Pathology Laboratory, Clarke Institute of Psychiatry, Toronto, Ontario, Canada
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17
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Cestaro B. Effects of arginine, S-adenosylmethionine and polyamines on nerve regeneration. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 1994; 154:32-41. [PMID: 7941963 DOI: 10.1111/j.1600-0404.1994.tb05407.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
INTRODUCTION Axon growth and axon regeneration are complex processes requiring an adequate supply of certain metabolic precursors and nutrients. MATERIAL AND METHODS This article reviews the studies examining some of the processes of protein modification fundamental to both nerve regeneration and to the continuous and adequate supply of specific factors such as arginine, S-adenosylmethionine and polyamines. RESULTS The process of arginylation notably increases following nerve injury and during subsequent regeneration of the nerve, with the most likely function of arginine-modification of nerve proteins being the degradation of proteins damaged through injury. It appears that defective methyl group metabolism may be one of the leading causes of demyelination, as suggested by the observation of reduced cerebrospinal fluid concentrations of s-adenosylmethionine (SAMe) and 5-methyltetrahydrofolate, the key metabolites in methylation processes, in patients with a reduction in myelination of corticospinal tracts. Polyamine synthesis, which depends strongly on the availability of both SAMe and arginine, markedly increases in neurons soon after an injury. This "polyamine-response" has been found to be essential for the survival of the parent neurons after injury to their axons. Polyamines probably exert their effects through involvement in DNA, RNA and protein synthesis, or through post-translational modifications that are indicated as the most relevant events of the "axon reaction." CONCLUSIONS Nerve regeneration requires the presence of arginine, s-adenosylmethionine, and polyamines. Further studies are needed to explore the mechanisms involved in these processes.
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Affiliation(s)
- B Cestaro
- Department of Biological Chemistry, University of Milan School of Medicine, Italy
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Morrison LD, Becker L, Kish SJ. S-adenosylmethionine decarboxylase in human brain. Regional distribution and influence of aging. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1993; 73:237-41. [PMID: 8353934 DOI: 10.1016/0165-3806(93)90143-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Recent experimental animal studies have implicated brain polyamines as having roles in both brain development and human brain neurodegenerative conditions. In order to provide baseline information, in normal human brain, on one of the key polyamine synthesising enzymes, S-adenosylmethionine decarboxylase (SAMDC), we examined the sensitivity of this enzyme to various cofactors/inhibitors, its regional distribution, and influence of aging in neurologically normal autopsied human brain. SAMDC in normal human brain is similar to that reported in other mammalian cells with regard to substrate affinity (Km = 39 microM), marked sensitivity to putrescine activation (+600%), inhibition (methylglyoxalbisguanidine and MDL 73811), and pH optimum (7.2). There was an uneven distribution of enzyme activity in human brain, and of the 12 brain regions examined, the highest activity was observed in occipital, parietal, frontal and temporal cortices (36-58 pmol/h/mg protein); intermediate activity in cerebellar and insular cortex, pulvinar thalamus, caudate and putamen (12-27 pmol/h/mg protein); and lowest activity in medial-dorsal thalamus, lateral globus pallidus and white matter (< 11 pmol/h/mg protein). The influence of aging (1 day to 103 years) on SAMDC activity in occipital cortex, the region showing the highest activity in human brain (n = 59) was also determined. Enzyme activity increased by approximately 600% from age 6 months to near maximal levels at age 10 years, then remained generally unchanged up to 103 years. Since SAMDC is a key regulatory enzyme in the synthesis of spermidine and spermine, the marked increase in SAMDC activity in the neonate and the sustained high enzyme levels throughout adulthood, imply a role for these polyamines in both development and mature brain function.
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Affiliation(s)
- L D Morrison
- Human Neurochemical Pathology Laboratory, Clarke Institute of Psychiatry, Toronto, Canada
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Morrison LD, Bergeron C, Kish SJ. Brain S-adenosylmethionine decarboxylase activity is increased in Alzheimer's disease. Neurosci Lett 1993; 154:141-4. [PMID: 8361629 DOI: 10.1016/0304-3940(93)90191-m] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We measured the activity of S-adenosylmethionine decarboxylase (SAMDC), a key regulatory enzyme of polyamine biosynthesis, in autopsied brain from 13 patients with Alzheimer's Disease (AD). As compared with the controls, mean enzyme activity was increased by 37-96% in all seven examined brain regions with statistically significant increases in temporal cortex (+96%), frontal cortex (+69%) and hippocampus (+90%). The elevated SAMDC may have occurred as part of a generalized polyamine response to brain injury, which has been previously described in experimental animal conditions. Above-normal SAMDC activity implies increased levels/metabolism of spermidine and spermine, two polyamines which are involved in neuronal regeneration, growth factor production, and activation of excitatory N-methyl-D-aspartate preferring glutamate receptors. Our data suggest the involvement of the polyamine system in the brain reparative and/or pathogenetic mechanisms of AD.
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Affiliation(s)
- L D Morrison
- Human Neurochemical Pathology Laboratory, Clarke Institute Of Psychiatry, Toronto, Ont., Canada
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