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Published: 10 March 2023

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1

WILLIAMS, Keith. "Interactions of polyamines with ion channels." Biochemical Journal 325, no. 2 (July 15, 1997): 289–97. http://dx.doi.org/10.1042/bj3250289.

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Endogenous polyamines, in particular spermine, have been found to cause block and modulation of a number of types of ion channel. Intracellular spermine is responsible for intrinsic gating and rectification of strong inward rectifier K+ channels by directly plugging the ion channel pore. These K+ channels control the resting membrane potential in both excitable and non-excitable cells, and control the excitability threshold in neurons and muscle cells. Intracellular spermine causes inward rectification at some subtypes of Ca2+-permeable glutamate receptors in the central nervous system, again by plugging the receptor channel pore, and spermine can even permeate the ion channel of these receptors. Extracellular spermine has multiple effects at the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor, including stimulation that increases the size of NMDA receptor currents, and voltage-dependent block. A number of polyamine-conjugated arthropod toxins and synthetic polyamine analogues are potent antagonists of glutamate receptors, and represent new tools with which to study these receptors. Interactions of polyamines with other types of cation channels have been reported. This area of research represents a new biology and a new pharmacology of polyamines.

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Liu, Lan, Rachel Santora, Jaladanki N. Rao, Xin Guo, Tongtong Zou, Huifang M. Zhang, Douglas J. Turner, and Jian-Ying Wang. "Activation of TGF-β-Smad signaling pathway following polyamine depletion in intestinal epithelial cells." American Journal of Physiology-Gastrointestinal and Liver Physiology 285, no. 5 (November 2003): G1056—G1067. http://dx.doi.org/10.1152/ajpgi.00151.2003.

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Smad proteins are transcription activators that are critical for transmitting transforming growth factor-β (TGF-β) superfamily signals from the cell surface receptors to the nucleus. Our previous studies have shown that cellular polyamines are essential for normal intestinal mucosal growth and that a decreased level of polyamines inhibits intestinal epithelial cell proliferation, at least partially, by increasing expression of TGF-β/TGF-β receptors. The current study went further to determine the possibility that Smads are the downstream intracellular effectors of activated TGF-β/TGF-β receptor signaling following polyamine depletion. Studies were conducted in IEC-6 cells derived from rat small intestinal crypts. Depletion of cellular polyamines by α-difluoromethylornithine (DFMO) increased basal levels of Smad3 and Smad4 proteins, induced their nuclear translocation, and stimulated Smad sequence-specific DNA-binding activity. Polyamine depletion-induced Smads were also associated with a significant increase in transcription activation as measured by luciferase reporter gene activity of Smad-dependent promoters. Inhibition of Smads by a dominant-negative mutant Smad4 in the DFMO-treated cells prevented the increased Smad transcription activation. Polyamine-deficient cells highly expressed TGF-β and were growth-arrested at the G1 phase. Inhibition of TGF-β by treatment with either immunoneutralizing anti-TGF-β antibody or TGF-β antisense oligodeoxyribonucleotides not only blocked the induction of Smad activity but also decreased the Smad-mediated transcriptional activation in polyamine-depleted cells. These findings suggest that Smads are involved in the downstream cellular processes mediated by cellular polyamines and that increased TGF-β/TGF-β receptor signaling following polyamine depletion activates Smads, thus resulting in the stimulation of Smad target gene expression.

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Santos, M. F., M. J. Viar, S. A. McCormack, and L. R. Johnson. "Polyamines are important for attachment of IEC-6 cells to extracellular matrix." American Journal of Physiology-Gastrointestinal and Liver Physiology 273, no. 1 (July 1, 1997): G175—G183. http://dx.doi.org/10.1152/ajpgi.1997.273.1.g175.

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The inhibition of ornithine decarboxylase, a rate-limiting enzyme of polyamine biosynthesis, with alpha-difluoromethylornithine in IEC-6 cells (small intestinal crypt cell line) reduces cell migration by 70%, inhibits protein cross-linking, and affects the cytoskeletal assembly. The current study examines the effects of intracellular polyamine depletion on attachment of IEC-6 cells to different matrices. Polyamine deficiency inhibited cell attachment to plastic, laminin, fibronectin, collagen IV, and Matrigel by different extents. Intracellular putrescine restored attachment to all matrices. The presence of a specific inhibitor of protein cross-linking also inhibited attachment to laminin in a dose-dependent manner. The inhibition of cell attachment to plastic and Matrigel was correlated with the inhibition of cell migration. Immunofluorescence studies showed that polyamines are essential for the correct expression of the integrin subunit alpha 2 but not for the expression of the alpha 1-subunit. This study demonstrates that polyamines are important for cell attachment and expression of the integrin alpha 2 beta 1, a putative receptor for collagen and laminin. The impairment of protein cross-linking and the inhibition of the expression of cell surface receptors that bind extracellular matrix (ECM) proteins may be part of the mechanism by which polyamine deficiency retards cell migration in the small intestine.

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Sedwick, Caitlin. "Uncorking AMPA receptors." Journal of General Physiology 150, no. 1 (December 12, 2017): 1. http://dx.doi.org/10.1085/jgp.201711966.

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Maeda, Yutaka, Christophe Rachez, Leo Hawel, Craig V. Byus, Leonard P. Freedman, and Frances M. Sladek. "Polyamines Modulate the Interaction between Nuclear Receptors and Vitamin D Receptor-Interacting Protein 205." Molecular Endocrinology 16, no. 7 (July 1, 2002): 1502–10. http://dx.doi.org/10.1210/mend.16.7.0883.

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Abstract Nuclear receptors (NR) activate transcription by interacting with several different coactivator complexes, primarily via LXXLL motifs (NR boxes) of the coactivator that bind a common region in the ligand binding domain of nuclear receptors (activation function-2, AF–2) in a ligand-dependent fashion. However, how nuclear receptors distinguish between different sets of coactivators remains a mystery, as does the mechanism by which orphan receptors such as hepatocyte nuclear factor 4α (HNF4α) activate transcription. In this study, we show that HNF4α interacts with a complex containing vitamin D receptor (VDR)-interacting proteins (DRIPs) in the absence of exogenously added ligand. However, whereas a full-length DRIP205 construct enhanced the activation by HNF4α in vivo, it did not interact well with the HNF4α ligand binding domain in vitro. In investigating this discrepancy, we found that the polyamine spermine significantly enhanced the interaction between HNF4α and full-length DRIP205 in an AF-2, NR-box-dependent manner. Spermine also enhanced the interaction of DRIP205 with the VDR even in the presence of its ligand, but decreased the interaction of both HNF4α and VDR with the p160 coactivator glucocorticoid receptor interacting protein 1 (GR1P1). We also found that GR1P1 and DRIP205 synergistically activated HNF4α-mediated transcription and that a specific inhibitor of polyamine biosynthesis, α-difluoromethylornithine (DFMO), decreased the ability of HNF4α to activate transcription in vivo. These results lead us to propose a model in which polyamines may facilitate the switch between different coactivator complexes binding to NRs.

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6

Pina, Fernando, M. Alexandra Bernardo, and Enrique García-España. "Fluorescent Chemosensors Containing Polyamine Receptors." European Journal of Inorganic Chemistry 2000, no. 10 (October 2000): 2143–57. http://dx.doi.org/10.1002/1099-0682(200010)2000:10<2143::aid-ejic2143>3.0.co;2-3.

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7

Grzelakowska-Sztabert, B., M. Dudkowska, and M. Manteuffel-Cymborowska. "Nuclear and membrane receptor-mediated signalling pathways modulate polyamine biosynthesis and interconversion." Biochemical Society Transactions 35, no. 2 (March 20, 2007): 386–90. http://dx.doi.org/10.1042/bst0350386.

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Polyamines play an important role in cell growth and differentiation, while their overproduction has potentially oncogenic consequences. Polyamine homoeostasis, a critical determinant of cell fate, is precisely tuned at the level of biosynthesis, degradation and transport. The enzymes ODC (ornithine decarboxylase), AdoMetDC (S-adenosylmethionine decarboxylase) and SSAT (spermidine/spermine N1-acetyltransferase) are critical for polyamine pool maintenance. Our experiments were designed to examine the expression of these enzymes in testosterone-induced hypertrophic and antifolate-induced hyperplastic mouse kidney, characterized by activation of AR (androgen receptor) and HGF (hepatocyte growth factor) membrane receptor c-Met respectively. The expression of these key enzymes was up-regulated by antifolate CB 3717 injury-evoked activation of HGF/c-Met signalling. In contrast, activation of the testosterone/AR pathway remarkably induced a selective increase in ODC expression without affecting other enzymes. Studies in catecholamine-depleted kidneys point to a synergistic interaction between the signalling pathways activated via cell membrane catecholamine receptors and AR, as well as c-Met. We found that this cross-talk modulated the expression of ODC and AdoMetDC, enzymes limiting polyamine biosynthesis, but not SSAT. This is in contrast with the antagonistic cross-talk between AR- and c-Met-mediated signalling which negatively regulated the expression of ODC, but affected neither AdoMetDC nor SSAT.

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Chen, Jie, Jaladanki N. Rao, Tongtong Zou, Lan Liu, Bernard S. Marasa, Lan Xiao, Xing Zeng, Douglas J. Turner, and Jian-Ying Wang. "Polyamines are required for expression of Toll-like receptor 2 modulating intestinal epithelial barrier integrity." American Journal of Physiology-Gastrointestinal and Liver Physiology 293, no. 3 (September 2007): G568—G576. http://dx.doi.org/10.1152/ajpgi.00201.2007.

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The Toll-like receptors (TLRs) allow mammalian intestinal epithelium to detect various microbes and activate innate immunity after infection. TLR2 and TLR4 have been identified in intestinal epithelial cells (IECs) as fundamental components of the innate immune response to bacterial pathogens, but the exact mechanism involved in control of TLR expression remains unclear. Polyamines are implicated in a wide variety of biological functions, and regulation of cellular polyamines is a central convergence point for the multiple signaling pathways driving different epithelial cell functions. The current study determined whether polyamines regulate TLR expression, thereby modulating intestinal epithelial barrier function. Depletion of cellular polyamines by inhibiting ornithine decarboxylase (ODC) with α-difluoromethylornithine decreased levels of TLR2 mRNA and protein, whereas increased polyamines by ectopic overexpression of the ODC gene enhanced TLR2 expression. Neither intervention changed basal levels of TLR4. Exposure of normal IECs to low-dose (5 μg/ml) LPS increased ODC enzyme activity and stimulated expression of TLR2 but not TLR4, while polyamine depletion prevented this LPS-induced TLR2 expression. Decreased TLR2 in polyamine-deficient cells was associated with epithelial barrier dysfunction. In contrast, increased TLR2 by the low dose of LPS enhanced epithelial barrier function, which was abolished by inhibition of TLR2 expression with specific, small interfering RNA. These results indicate that polyamines are necessary for TLR2 expression and that polyamine-induced TLR2 activation plays an important role in regulating epithelial barrier function.

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Wu, Guoyao, Nick E. Flynn, and Darrell A. Knabe. "Enhanced intestinal synthesis of polyamines from proline in cortisol-treated piglets." American Journal of Physiology-Endocrinology and Metabolism 279, no. 2 (August 1, 2000): E395—E402. http://dx.doi.org/10.1152/ajpendo.2000.279.2.e395.

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This study was conducted to determine a role for cortisol in regulating intestinal ornithine decarboxylase (ODC) activity and to identify the metabolic sources of ornithine for intestinal polyamine synthesis in suckling pigs. Thirty-two 21-day-old suckling pigs were randomly assigned to one of four groups with eight animals each and received daily intramuscular injections of vehicle solution (sesame oil; control), hydrocortisone 21-acetate (HYD; 25 mg/kg body wt), RU-486 (10 mg/kg body wt, a potent blocker of glucocorticoid receptors), or HYD plus RU-486 for two consecutive days. At 29 days of age, pigs were killed for preparation of jejunal enterocytes. The cytosolic fraction was prepared for determining ODC activity. For metabolic studies, enterocytes were incubated for 45 min at 37°C in 2 ml of Krebs-bicarbonate buffer (pH 7.4) containing 1 mM [U-14C]arginine, 1 mM [U-14C]ornithine, 1 mM [U-14C]glutamine, or 1 mM [U-14C]proline plus 1 mM glutamine. Cortisol administration increased intestinal ODC activity by 230%, polyamine (putrescine, spermidine, and spermine) synthesis from ornithine and proline by 75–180%, and intracellular polyamine concentrations by 45–83%. Polyamine synthesis from arginine was not detected in enterocytes of control pigs but was induced in cells of cortisol-treated pigs. There was no detectable synthesis of polyamines from glutamine in enterocytes of all groups of pigs. The stimulating effects of cortisol on intestinal ODC activity and polyamine synthesis were abolished by coadministration of RU-486. Our data indicate that an increase in plasma cortisol concentrations stimulates intestinal polyamine synthesis via a glucocorticoid receptor-mediated mechanism and that proline (an abundant amino acid in milk) is a major source of ornithine for intestinal polyamine synthesis in suckling neonates.

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Wilding, Timothy J., Kevin Chen, and James E. Huettner. "Fatty acid modulation and polyamine block of GluK2 kainate receptors analyzed by scanning mutagenesis." Journal of General Physiology 136, no. 3 (August 30, 2010): 339–52. http://dx.doi.org/10.1085/jgp.201010442.

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RNA editing of kainate receptor subunits at the Q/R site determines their susceptibility to inhibition by cis-unsaturated fatty acids as well as block by cytoplasmic polyamines. Channels comprised of unedited (Q) subunits are strongly blocked by polyamines, but insensitive to fatty acids, such as arachidonic acid (AA) and docosahexaenoic acid (DHA), whereas homomeric edited (R) channels resist polyamine block but are inhibited by AA and DHA. In the present study, we have analyzed fatty acid modulation of whole-cell currents mediated by homomeric recombinant GluK2 (formerly GluR6) channels with individual residues in the pore-loop, M1 and M3 transmembrane helices replaced by scanning mutagenesis. Our results define three abutting surfaces along the M1, M2, and M3 helices where gain-of-function substitutions render GluK2(Q) channels susceptible to fatty acid inhibition. In addition, we identify four locations in the M3 helix (F611, L614, S618, and T621) at the level of the central cavity where Arg substitution increases relative permeability to chloride and eliminates polyamine block. Remarkably, for two of these positions, L614R and S618R, exposure to fatty acids reduces the apparent chloride permeability and potentiates whole-cell currents ∼5 and 2.5-fold, respectively. Together, our results suggest that AA and DHA alter the orientation of M3 in the open state, depending on contacts at the interface between M1, M2, and M3. Moreover, our results demonstrate the importance of side chains within the central cavity in determining ionic selectivity and block by cytoplasmic polyamines despite the inverted orientation of GluK2 as compared with potassium channels and other pore-loop family members.

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11

Riaza Bermudo-Soriano, C., C. Vaquero-Lorenzo, M. Dîaz-Hernândez, M. Garda Dorado, P. Sânchez-Pâez, I. Durân Cristobal, R. Manzanero Estopinân, et al. "Blood polyamine levels in drug-free schizophrenics." European Psychiatry 26, S2 (March 2011): 1492. http://dx.doi.org/10.1016/s0924-9338(11)73196-0.

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BackgroundNatural polyamines (putrescine, spermidine and spermine) are low molecular weight highly protonated aliphatic molecules that physiologically modulate NMDA, AMPA/kainate glutamatergic receptors and limbic dopaminergic neurotransmission. Previous studies had demonstrated that polyamine metabolism might be disrupted in schizophrenia, what could potentially be linked to glutamatergic dysfunction. In particular, polyamine levels in blood and fibroblast cultures from patients with schizophrenia had previously been found to be higher than in healthy controls. Indeed, a significant positive correlation between blood polyamine levels and severity of illness may exist.MethodsIn order to test potential differences in blood polyamine levels between drug-free schizophrenia in-patients (n = 12), and healthy controls (n = 26, blood donors), spermidine (spd), spermine (spm), and spermidine/spermine index (spd/spm) were determined using HPLC after dansylation.ResultsNo significant differences were found between groups (t = 0,974; df = 36; P = 0,337 for spd, t = l0, 52; df = 36; P = 0,959 for Spm, and, t = 0, 662; df = 36; P = 0,512 for spd/spm).ConclusionsThough we couldn’t replicate previous findings suggesting disturbances in blood polyamine levels in schizophrenia, this issue may be a promising target. Future research should take into account possible factors such as sex, nutritional state, and stress.

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12

Cervetto, Chiara, Monica Averna, Laura Vergani, Marco Pedrazzi, Sarah Amato, Simone Pelassa, Stefano Giuliani, et al. "Reactive Astrocytosis in a Mouse Model of Chronic Polyamine Catabolism Activation." Biomolecules 11, no. 9 (August 25, 2021): 1274. http://dx.doi.org/10.3390/biom11091274.

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Background: In the brain, polyamines are mainly synthesized in neurons, but preferentially accumulated in astrocytes, and are proposed to be involved in neurodegenerative/neuroinflammatory disorders and neuron injury. A transgenic mouse overexpressing spermine oxidase (SMOX, which specifically oxidizes spermine) in the neocortex neurons (Dach-SMOX mouse) was proved to be a model of increased susceptibility to excitotoxic injury. Methods: To investigate possible alterations in synapse functioning in Dach-SMOX mouse, both cerebrocortical nerve terminals (synaptosomes) and astrocytic processes (gliosomes) were analysed by assessing polyamine levels, ezrin and vimentin content, glutamate AMPA receptor activation, calcium influx, and catalase activity. Results: The main findings are as follows: (i) the presence of functional calcium-permeable AMPA receptors in synaptosomes from both control and Dach-SMOX mice, and in gliosomes from Dach-SMOX mice only; (ii) reduced content of spermine in gliosomes from Dach-SMOX mice; and (iii) down-regulation and up-regulation of catalase activity in synaptosomes and gliosomes, respectively, from Dach-SMOX mice. Conclusions: Chronic activation of SMOX in neurons leads to major changes in the astrocyte processes including reduced spermine levels, increased calcium influx through calcium-permeable AMPA receptors, and stimulation of catalase activity. Astrocytosis and the astrocyte process alterations, depending on chronic activation of polyamine catabolism, result in synapse dysregulation and neuronal suffering.

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Brown, Patricia M. G. E., Hugo McGuire, and Derek Bowie. "Stargazin and cornichon-3 relieve polyamine block of AMPA receptors by enhancing blocker permeation." Journal of General Physiology 150, no. 1 (December 8, 2017): 67–82. http://dx.doi.org/10.1085/jgp.201711895.

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Most ligand- and voltage-gated ion channels assemble as signaling complexes consisting of pore-forming and auxiliary subunits. In the mammalian brain, AMPA-type ionotropic glutamate receptors (AMPARs) coassemble with several families of auxiliary subunits that regulate channel gating as well as ion channel block and permeation. Previous work has shown that auxiliary proteins stargazin (or γ2) and cornichon-3 (CNIH-3) attenuate the cytoplasmic polyamine channel block of AMPARs, although the underlying mechanism has yet to be established. Here, we show that γ2 and CNIH-3 relieve channel block by enhancing the rate of blocker permeation. Surprisingly, the relative permeability of the polyamine spermine (Spm) through the pore of the AMPAR-γ2 or -CNIH-3 complexes is considerably more than AMPARs expressed alone. Spm permeability is comparable to that of Na+ for the GluA2-γ2 complex and four times greater than Na+ with GluA2 + CNIH-3. A modified model of permeant channel block fully accounts for both the voltage- and time-dependent nature of Spm block. Estimates of block rate constants reveal that auxiliary subunits do not attenuate block by shifting the location of the block site within the membrane electric field, and they do not affect the blocker’s ability to reach it. Instead, γ2 and CNIH-3 relieve channel block by facilitating the blocker’s exit rates from the open channel. From a physiological perspective, the relief of channel block exerted by γ2 and CNIH-3 ensures that there is unfettered signaling by AMPARs at glutamatergic synapses. Moreover, the pronounced ability of AMPARs to transport polyamines may have an unexpected role in regulating cellular polyamine levels.

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Mellor, Ian R., and Peter N. R. Usherwood. "Targeting ionotropic receptors with polyamine-containing toxins☆." Toxicon 43, no. 5 (April 2004): 493–508. http://dx.doi.org/10.1016/j.toxicon.2004.02.003.

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15

Ilioudis, Christos A., and Jonathan W. Steed. "Organic macrocyclic polyamine-based receptors for anions." Journal of Supramolecular Chemistry 1, no. 4-6 (July 2001): 165–87. http://dx.doi.org/10.1016/s1472-7862(02)00026-6.

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16

Pina, Fernando, M. Alexandra Bernardo, and Enrique Garcia-Espana. "ChemInform Abstract: Fluorescent Chemosensors Containing Polyamine Receptors." ChemInform 31, no. 50 (December 12, 2000): no. http://dx.doi.org/10.1002/chin.200050258.

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Pitarch-Jarque, Javier, Raquel Belda, Laura García-España, José M. Llinares, FangFang Pan, Kari Rissanen, Pilar Navarro, and Enrique García-España. "From isolated 1H-pyrazole cryptand anion receptors to hybrid inorganic–organic 1D helical polymeric anion receptors." Dalton Transactions 44, no. 17 (2015): 7761–64. http://dx.doi.org/10.1039/c5dt00763a.

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We report a 1-D helical coordination polymer formed by protonated polyamine 1H-pyrazole cryptands interconnected by Cu²⁺metal ions that are able to encapsulate chloride anions behaving as a multianion receptor.

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18

Dunn, Andrew, and Donglu Shi. "Polymeric Vectors for Strategic Delivery of Nucleic Acids." Nano LIFE 07, no. 02 (June 2017): 1730003. http://dx.doi.org/10.1142/s1793984417300035.

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Genomic modification through nucleic acid delivery is a frequently applied method in fundamental biological studies and offers a potent therapeutic strategy for disease treatment and biological research. Delivery of nucleic sequences is therefore an attractive facet of biological nanotechnology as highly specific, efficient, and nonantagonistic delivery is necessary for in vivo and clinical use. Previous vectors have suffered from immunogenic responses, serum dependent inactivation, and cytotoxicity, hindering their translational applicability. Current research in polymeric-based nucleotide delivery strives to offer a highly biocompatible, broad use vector through the utilization of polypeptide and polyamine conjugation that can be easily tailored for specific targeting or wide dissemination. Cross-linking low molecular weight polyamines and lipophilic derivatization for amphiphile creation has lead to improved biocompatibility and transfection efficiency compared to higher molecular weight polyamines. Derivatization of hyperbranched and dendritic polyamido- and polyamines has allowed for the formation of efficient in vivo transfection vectors; ring opening synthesis of N-carboxyanhydride amino acids have led to controlled peptide architectures for improved transfection while simultaneously providing convenient primary amines useful in functionalization. Polymer libraries of poly(ß-amino esters) have provided insights into useful architectures for in vitro and in vivo gene delivery. Grafting small molecules to polyamines, such as folate and galactose, for enhanced interaction with cell surface receptors for selective targeting of specific cell types has proven to be encouraging and remains a prominent aspect in biological nanotechnology.

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UPP, JAMES R., RAMI SAYDJARI, COURTNEY M. TOWNSEND, POMILA SINGH, SAM C. BARRANCO, and JAMES C. THOMPSON. "Polyamine Levels and Gastrin Receptors in Colon Cancers." Annals of Surgery 207, no. 6 (June 1988): 662–69. http://dx.doi.org/10.1097/00000658-198806000-00004.

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Wichmann, Kathrin, Bianca Antonioli, Tilo Söhnel, Marco Wenzel, Kerstin Gloe, Karsten Gloe, Jason R. Price, Leonard F. Lindoy, Alexander J. Blake, and Martin Schröder. "Polyamine-based anion receptors: Extraction and structural studies." Coordination Chemistry Reviews 250, no. 23-24 (December 2006): 2987–3003. http://dx.doi.org/10.1016/j.ccr.2006.07.010.

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Cervelli, Manuela, Monica Averna, Laura Vergani, Marco Pedrazzi, Sarah Amato, Cristian Fiorucci, Marianna Nicoletta Rossi, et al. "The Involvement of Polyamines Catabolism in the Crosstalk between Neurons and Astrocytes in Neurodegeneration." Biomedicines 10, no. 7 (July 21, 2022): 1756. http://dx.doi.org/10.3390/biomedicines10071756.

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In mammalian cells, the content of polyamines is tightly regulated. Polyamines, including spermine, spermidine and putrescine, are involved in many cellular processes. Spermine oxidase specifically oxidizes spermine, and its deregulated activity has been reported to be linked to brain pathologies involving neuron damage. Spermine is a neuromodulator of a number of ionotropic glutamate receptors and types of ion channels. In this respect, the Dach-SMOX mouse model overexpressing spermine oxidase in the neocortex neurons was revealed to be a model of chronic oxidative stress, excitotoxicity and neuronal damage. Reactive astrocytosis, chronic oxidative and excitotoxic stress, neuron loss and the susceptibility to seizure in the Dach-SMOX are discussed here. This genetic model would help researchers understand the linkage between polyamine dysregulation and neurodegeneration and unveil the roles of polyamines in the crosstalk between astrocytes and neurons in neuroprotection or neurodegeneration.

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Mattison, Hayley A., Ashish A. Bagal, Michael Mohammadi, Nisha S. Pulimood, Christian G. Reich, Bradley E. Alger, Joseph P. Y. Kao, and Scott M. Thompson. "Evidence of calcium-permeable AMPA receptors in dendritic spines of CA1 pyramidal neurons." Journal of Neurophysiology 112, no. 2 (July 15, 2014): 263–75. http://dx.doi.org/10.1152/jn.00578.2013.

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GluA2-lacking, calcium-permeable α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors (AMPARs) have unique properties, but their presence at excitatory synapses in pyramidal cells is controversial. We have tested certain predictions of the model that such receptors are present in CA1 cells and show here that the polyamine spermine, but not philanthotoxin, causes use-dependent inhibition of synaptically evoked excitatory responses in stratum radiatum, but not s. oriens, in cultured and acute hippocampal slices. Stimulation of single dendritic spines by photolytic release of caged glutamate induced an N-methyl-d-aspartate receptor-independent, use- and spermine-sensitive calcium influx only at apical spines in cultured slices. Bath application of glutamate also triggered a spermine-sensitive influx of cobalt into CA1 cell dendrites in s. radiatum. Responses of single apical, but not basal, spines to photostimulation displayed prominent paired-pulse facilitation (PPF) consistent with use-dependent relief of cytoplasmic polyamine block. Responses at apical dendrites were diminished, and PPF was increased, by spermine. Intracellular application of pep2m, which inhibits recycling of GluA2-containing AMPARs, reduced apical spine responses and increased PPF. We conclude that some calcium-permeable, polyamine-sensitive AMPARs, perhaps lacking GluA2 subunits, are present at synapses on apical dendrites of CA1 pyramidal cells, which may allow distinct forms of synaptic plasticity and computation at different sets of excitatory inputs.

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Doğgan, Aclan, A. Muralikrishna Rao, Mustafa K. Başkaya, V. L. Raghavendra Rao, Jane Rastl, David Donaldson, and Robert J. Dempsey. "Effects of ifenprodil, a polyamine site NMDA receptor antagonist, on reperfusion injury after transient focal cerebral ischemia." Journal of Neurosurgery 87, no. 6 (December 1997): 921–26. http://dx.doi.org/10.3171/jns.1997.87.6.0921.

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✓ Polyamines and N-methyl-d-aspartate (NMDA) receptors are both thought to play an important role in secondary neuronal injury after cerebral ischemia. Ifenprodil, known as a noncompetitive inhibitor of polyamine sites at the NMDA receptor, was studied after transient focal cerebral ischemia occurred. Spontaneously hypertensive male rats, each weighing between 250 and 350 g, underwent 3 hours of tandem middle cerebral artery (MCA) and common carotid artery occlusion followed by reperfusion for a period of 3 hours or 21 hours. Intravenous ifenprodil (10 µg/kg/minute) or saline infusion was started immediately after the onset of MCA occlusion and continued throughout the ischemic period. Physiological parameters including blood pressure, blood gas levels, blood glucose, hemoglobin, and rectal and temporal muscle temperatures were monitored. Six rats from each group were evaluated at 6 hours postocclusion for brain water content, an indicator of brain edema, and Evans blue dye extravasation for blood-brain barrier breakdown. Infarct volume was also measured in six rats from each group at 6 and 24 hours postocclusion. Ifenprodil treatment significantly reduced brain edema (82.5 ± 0.4% vs. 83.5 ± 0.4%, p < 0.05) and infarct volume (132 ± 14 mm3 vs. 168 ± 25 mm3, p < 0.05) compared with saline treatment, with no alterations in temporal muscle (brain) or rectal (body) temperature (35.9 ± 0.4°C vs. 36.2 ± 0.2°C; 37.7 ± 0.4°C vs. 37.6 ± 0.6°C; not significant). These results demonstrate that ifenprodil has neuroprotective properties after ischemia/reperfusion injury in the absence of hypothermia. This indicates that antagonists selective for the polyamine site of the NMDA receptors may be a viable treatment option and helps to explain some of the pathophysiological mechanisms involved in secondary injury after transient focal cerebral ischemia has occurred.

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Linsalata, M., C. Messa, F. Russo, A. Cavallini, and A. Dileo. "Estrogen Receptors and Polyamine Levels in Human Gastric Carcinoma." Scandinavian Journal of Gastroenterology 29, no. 1 (January 1994): 67–70. http://dx.doi.org/10.3109/00365529409090439.

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Strømgaard, Kristian, Lars S. Jensen, and Stine B. Vogensen. "Polyamine toxins: development of selective ligands for ionotropic receptors." Toxicon 45, no. 3 (March 2005): 249–54. http://dx.doi.org/10.1016/j.toxicon.2004.11.013.

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Lewin, Anita H., Guobin Sun, Louise Fudala, Hernan Navarro, Li-Ming Zhou, Piotr Popik, Alexander Faynsteyn, and Phil Skolnick. "Molecular Features Associated with Polyamine Modulation of NMDA Receptors." Journal of Medicinal Chemistry 41, no. 6 (March 1998): 988–95. http://dx.doi.org/10.1021/jm9707129.

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27

Fujita-Yamaguchi, Y., D. B. Sacks, J. M. McDonald, D. Sahal, and S. Kathuria. "Effect of basic polycations and proteins on purified insulin receptor. Insulin-independent activation of the receptor tyrosine-specific protein kinase by poly(l-lysine)." Biochemical Journal 263, no. 3 (November 1, 1989): 813–22. http://dx.doi.org/10.1042/bj2630813.

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Since the studies on tyrosine phosphorylation of calmodulin by the insulin receptor kinase in vitro suggested that protamine and poly(L-lysine) may activate phosphorylation of the receptor beta subunit [Sacks & McDonald (1988) J. Biol. Chem. 263, 2377-2383], we examined the effects of a variety of basic polycations/proteins and polyamines on insulin receptor kinase activity. The insulin receptor purified from human placental membranes was incubated with each basic polycation/protein or polyamine and assayed for tyrosine-specific protein kinase activity by measuring 32P incorporation into the src-related peptide. At a concentration of 1 microM, poly(L-lysine) and poly(L-ornithine) markedly stimulated kinase activity, whereas poly(L-arginine) and histones H1 and H2B inhibited insulin receptor kinase. In contrast, at a concentration of 1 mM, three polyamines (spermine, spermidine and putrescine) did not alter kinase activity. Poly(L-lysine) and poly(L-ornithine) stimulated the insulin receptor kinase by 5-10-fold at concentrations of 0.1-1 microM. Protamine sulphate also showed a significant stimulatory effect at a concentration of 100 microM. Preincubation of the receptor with poly(L-lysine) or poly(L-ornithine) for 20-60 min resulted in maximal kinase activation. Poly(L-lysine), the most effective activator of the receptor kinase, was used to characterize further the mechanisms of the kinase activation. Poly(L-lysine) activates the insulin receptor kinase by increasing the Vmax. without changing the Km. Poly(L-lysine) markedly stimulates the kinase activity of insulin receptor preparations that have lost both basal kinase activity and the ability to be stimulated by insulin. Insulin and poly(L-lysine) also differed in their ability to stimulate the kinase activity of prephosphorylated receptors. Prephosphorylation of the receptors did not affect the stimulation of the kinase by insulin. In contrast, prephosphorylation of receptors resulted in a markedly enhanced ability of poly(L-lysine) to stimulate kinase activity. These studies suggest that the mechanisms by which poly(L-lysine) and insulin activate the kinase are different. In conjunction with other additional evidence, it is suggested that poly(L-lysine) interacts directly with the beta-subunit of the receptor, thereby activating the receptor kinase.

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Blagbrough, Ian S., and Peter N. R. Usherwood. "Polyamine amide toxins as pharmacological tools and pharmaceutical agents." Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 99, no. 1-2 (1992): 67–81. http://dx.doi.org/10.1017/s0269727000013063.

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Synopsis:The polyamine amides comprise a newly-discovered class of compounds which exhibits considerable potential for the development of selective pharmacological tools and pharmaceutical agents. In mammals and other vertebrates, they are selective, non-competitive antagonists of ionotropic glutamate receptors, but they also interact with other ionotropic receptors (e.g. nicotinic acetylcholine receptors). Thus, they are channel blockers which are selective for cation channels. We report on synthetic studies undertaken to produce hybrid analogues of these toxins based upon the argiotoxins of spider venoms and the philanthotoxins of parasitic, predatory wasp venom. The synthesis and characterisation of a mono-acylated spermine is also described. In addition, an account of current views on the many possible sites and modes of actions of the polyamine amides is presented and their potential for therapeutic neurochemistry, e.g. for the possible treatment of ischaemic damage to the nervous system, is highlighted.

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Wang, Rui, Changqing Xu, Weimin Zhao, Jing Zhang, Kun Cao, Baofeng Yang, and Lingyun Wu. "Calcium and polyamine regulated calcium-sensing receptors in cardiac tissues." European Journal of Biochemistry 270, no. 12 (June 2003): 2680–88. http://dx.doi.org/10.1046/j.1432-1033.2003.03645.x.

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Soto, David, Ian D. Coombs, Leah Kelly, Mark Farrant, and Stuart G. Cull-Candy. "Stargazin attenuates intracellular polyamine block of calcium-permeable AMPA receptors." Nature Neuroscience 10, no. 10 (September 16, 2007): 1260–67. http://dx.doi.org/10.1038/nn1966.

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Blagbrough, Ian S., Barrie W. Bycroft, and Peter N. R. Usherwood. "NATURAL AND SYNTHETIC POLYAMINE DERIVATIVES AS ANTAGONISTS OF GLUTAMATE RECEPTORS." Journal of Pharmacy and Pharmacology 42, S1 (December 1990): 73P. http://dx.doi.org/10.1111/j.2042-7158.1990.tb14446.x.

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32

Panchenko, Victor A., Carla R. Glasser, and Mark L. Mayer. "Structural Similarities between Glutamate Receptor Channels and K+ Channels Examined by Scanning Mutagenesis." Journal of General Physiology 117, no. 4 (March 28, 2001): 345–60. http://dx.doi.org/10.1085/jgp.117.4.345.

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The pores of glutamate receptors and K+ channels share sequence homology, suggesting a conserved secondary structure. Scanning mutagenesis with substitution of alanine and tryptophan in GluR6 channels was performed based on the structure of KcsA. Our assay used disruption of voltage-dependent polyamine block to test for changes in the packing of pore-forming regions. Alanine scanning from D567 to R603 revealed reduced rectification resulting from channel block in two regions. A periodic pattern from F575 to M589 aligned with the pore helix in KcsA, whereas a cluster of sensitive positions around Q590, a site regulated by RNA editing, mapped to the selectivity filter in KcsA. Tryptophan scanning from D567 to R603 revealed similar patterns, but with a complete disruption of spermine block for 7 out of the 37 positions and a pM dissociation constant for Q590W. Molecular modeling with KcsA coordinates showed that GluR6 pore helix mutants disrupting polyamine block pack against M1 and M2, and are not exposed in the ion channel pore. In the selectivity filter, tryptophan creates an aromatic cage consistent with the pM dissociation constant for Q590W. A scan with glutamate substitution was used to map the cytoplasmic entrance to the pore based on charge neutralization experiments, which established that E594 was uniquely required for high affinity polyamine block. In E594Q mutants, introduction of glutamate at positions S593–L600 restored polyamine block at positions corresponding to surface-exposed residues in KcsA. Our results reinforce proposals that the pore region of glutamate receptors contains a helix and pore loop analogous to that found in K+ channels. At the cytoplasmic entrance of the channel, a negatively charged amino acid, located in an extended loop with solvent-exposed side chains, is required for high affinity polyamine block and probably attracts cations via a through space electrostatic mechanism.

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33

De Sarro, G., F. Nava, G. Calapai, and A. De Sarro. "Effects of some excitatory amino acid antagonists and drugs enhancing gamma-aminobutyric acid neurotransmission on pefloxacin-induced seizures in DBA/2 mice." Antimicrobial Agents and Chemotherapy 41, no. 2 (February 1997): 427–34. http://dx.doi.org/10.1128/aac.41.2.427.

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The behavioral and convulsant effects of pefloxacin (PEFLO), a quinolone derivative, were studied after intraperitoneal (i.p.) administration to Dilute Brown Agouti DBA/2J (DBA/2) mice, a strain genetically susceptible to sound-induced seizures. The anticonvulsant effects of some excitatory amino acid (EAA) antagonists acting at N-methyl-D-aspartate (NMDA) or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate (KA) receptors and of some compounds enhancing gamma-aminobutyric acid (GABA)-ergic transmission against seizures induced by PEFLO were also evaluated. The present study demonstrated that both groups of compounds administered i.p. or intracerebroventricularly were able to protect against seizures induced by PEFLO. However, ifenprodil and (+/-)-alpha-(chlorophenyl)-4-[(4-fluorophenyl)methyl]-1-piperidine-ethan ol (SL 82.0715), two compounds acting on the polyamine site of the NMDA receptor complex, were unable to provide any protection. The relationship between the different sites of action and the anticonvulsant activities of these derivatives were discussed. Although the main mechanisms of PEFLO-induced seizures cannot be easily determined, potential interactions with the receptors of EAA exist. In fact, antagonists of EAA, and in particular, those acting at NMDA receptors, were able to increase the threshold for the seizures or to prevent the seizures induced by PEFLO, while compounds acting at the polyamine site did not provide any protection. The AMPA-KA receptor antagonists were also able to exert anticonvulsant activity, but with minor potency in comparison to those of NMDA antagonists. In addition, the fact that compounds enhancing GABA-ergic neurotransmission were also able to protect the mice against seizures induced by PEFLO suggests an involvement of GABA system.

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Segal, Jeff A., and Phil Skolnick. "Polyamine-like actions of aminoglycosides and aminoglycoside derivatives at NMDA receptors." European Journal of Pharmacology 347, no. 2-3 (April 1998): 311–17. http://dx.doi.org/10.1016/s0014-2999(98)00108-3.

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35

Notarnicola, Maria, Michele Linsalata, Maria Gabriella Caruso, Aldo Cavallini, and Alfredo Di Leo. "Low density lipoprotein receptors and polyamine levels in human colorectal adenocarcinoma." Journal of Gastroenterology 30, no. 6 (December 1995): 705–9. http://dx.doi.org/10.1007/bf02349635.

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36

Rozov, Andrei, and Nail Burnashev. "Polyamine-dependent facilitation of postsynaptic AMPA receptors counteracts paired-pulse depression." Nature 401, no. 6753 (October 1999): 594–98. http://dx.doi.org/10.1038/44151.

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37

Poulsen, Mette H., Niels G. Nørager, Martin Sumser, Dirk Trauner, and Kristian Strømgaard. "Characterization of Light-Controllable Polyamine Toxin Inhibitors of Ionotropic Glutamate Receptors." Biophysical Journal 106, no. 2 (January 2014): 150a—151a. http://dx.doi.org/10.1016/j.bpj.2013.11.867.

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38

Wu, Guoyao, Nick E. Flynn, Darrell A. Knabe, and Laurie A. Jaeger. "A cortisol surge mediates the enhanced polyamine synthesis in porcine enterocytes during weaning." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 279, no. 2 (August 1, 2000): R554—R559. http://dx.doi.org/10.1152/ajpregu.2000.279.2.r554.

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This study was conducted to determine whether a cortisol surge mediates the enhanced expression of intestinal ornithine decarboxylase (ODC) in weanling pigs. Piglets were nursed by sows until 21 days of age, when 40 pigs were randomly assigned into one of four groups (10 animals/group). Group 1continued to be fed by sows, whereas groups 2–4 were weaned to a corn and soybean meal-based diet. Weanling pigs received intramuscular injections of vehicle solvent (sesame oil), RU-486 (a potent blocker of glucocorticoid receptors; 10 mg/kg body wt), and metyrapone (an inhibitor of adrenal cortisol synthesis; 5 mg/kg body wt), respectively, 5 min before weaning and 24 and 72 h later. At 29 days of age, pigs were used to prepare jejunal enterocytes for ODC assay and metabolic studies. To determine polyamine (putrescine, spermidine, and spermine) synthesis, enterocytes were incubated for 45 min at 37°C in 2 ml Krebs-bicarbonate buffer containing 1 mM [U-14C]arginine, 1 mM [U-14C]ornithine, 1 mM [U-14C]glutamine, or 1 mM [U-14C]proline plus 1 mM glutamine. Weaning increased intestinal ODC activity by 230% and polyamine synthesis from ornithine, arginine, and proline by 72–157%. Arginine was a quantitatively more important substrate than proline for intestinal polyamine synthesis in weaned pigs. Administration of RU-486 or metyrapone to weanling pigs prevented the increases in intestinal ODC activity and polyamine synthesis, reduced intracellular polyamine concentrations, and decreased villus heights and intestinal growth. Our results demonstrate an essential role for a cortisol surge in enhancing intestinal polyamine synthesis during weaning, which may be of physiological importance for intestinal adaptation and remodeling.

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McCormack, Shirley A., Ramesh M. Ray, Patrick M. Blanner, and Leonard R. Johnson. "Polyamine depletion alters the relationship of F-actin, G-actin, and thymosin β4 in migrating IEC-6 cells." American Journal of Physiology-Cell Physiology 276, no. 2 (February 1, 1999): C459—C468. http://dx.doi.org/10.1152/ajpcell.1999.276.2.c459.

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The cause of reduced migration ability in polyamine-deficient cells is not known, but their actin cytoskeleton is clearly abnormal. We depleted polyamines with α-difluoromethylornithine (DFMO) in migrating cells with or without stimulation by epidermal growth factor (EGF) and investigated filamentous (F-) actin, monomeric (G-) actin, and thymosin β4 (Tβ4), using immunofluorescent confocal microscopy, DNase assay, and immunoblot analysis. DFMO reduced F-actin in the cell interior, increased it in the cell cortex, redistributed G-actin, and increased nuclear staining of Tβ4. However, DFMO did not affect the amount of Tβ4 mRNA. EGF caused a rapid increase in the staining of F-actin in control cells, but DFMO prevented this response to EGF. Despite the visible changes shown by immunocytochemistry, statistically significant changes in the amount of either actin isoform or of total actin did not occur. We propose that DFMO reduces migration by interfering with the sequestration of G-actin by Tβ4 and the association of F-actin with activated EGF receptors.

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40

Marathe, Chaitra, Michelle N. Bradley, Cynthia Hong, Felix Lopez, Carlos M. Ruiz de Galarreta, Peter Tontonoz, and Antonio Castrillo. "The Arginase II Gene Is an Anti-inflammatory Target of Liver X Receptor in Macrophages." Journal of Biological Chemistry 281, no. 43 (August 30, 2006): 32197–206. http://dx.doi.org/10.1074/jbc.m605237200.

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The liver X receptors (LXRs) are ligand-dependent transcription factors that have been implicated in lipid metabolism and inflammation. LXRs also inhibit the expression of inflammatory genes in macrophages, including inducible nitric oxide synthase (iNOS). Some of these actions are mediated through LXR antagonism of NF-κB activity. The potential for LXRs to positively regulate the expression of anti-inflammatory molecules, however, has not been explored. Here we show that the arginase II (ArgII) gene is a direct target for LXR regulation. ArgII catalyzes the conversion of l-arginine into l-ornithine and urea, leading to the synthesis of polyamines. Expression of ArgII is induced by LXR agonists in macrophage cell lines and primary murine macrophages in a receptor-dependent manner. The ArgII promoter contains a functional LXR response elements that mediates promoter induction by LXR/RXR (retinoid X receptor) in transfection assays. Since ArgII and iNOS utilize a common substrate, induction of ArgII expression has the potential to exert anti-inflammatory effects by shifting arginine metabolism toward polyamine synthesis at the expense of NO production. In support of this hypothesis, we demonstrate that forced expression of ArgII mimics the inhibitory effect of LXR activation on macrophage NO production. Furthermore, inhibition of arginase activity partially reverses the inhibitory effect of LXR agonists on NO production. These studies suggest that regulation of ArgII may contribute to the immunomodulatory effects of LXRs.

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41

Masuko, Takashi, Rie Namiki, Yuta Nemoto, Muneharu Miyake, Yasuo Kizawa, Toyofumi Suzuki, Keiko Kashiwagi, Kazuei Igarashi, and Tadashi Kusama. "Neuroprotection by Tosyl-Polyamine Derivatives through the Inhibition of Ionotropic Glutamate Receptors." Journal of Pharmacology and Experimental Therapeutics 331, no. 2 (July 30, 2009): 522–30. http://dx.doi.org/10.1124/jpet.109.152926.

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42

Soto, David, Ian D. Coombs, Leah Kelly, Mark Farrant, and Stuart G. Cull-Candy. "Erratum: Corrigendum: Stargazin attenuates intracellular polyamine block of calcium-permeable AMPA receptors." Nature Neuroscience 10, no. 12 (December 2007): 1634. http://dx.doi.org/10.1038/nn1207-1634a.

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43

Bazzicalupi, Carla, Andrea Bencini, Antonio Bianchi, Claudia Borri, Andrea Danesi, Enrique Garcia-España, Claudia Giorgi, and Barbara Valtancoli. "Polyfunctional Recognition of Pyridinedicarboxylate Anions with Macrocyclic Polyamine Receptors Containing Heteroaromatic Groups." Journal of Organic Chemistry 73, no. 21 (November 7, 2008): 8286–95. http://dx.doi.org/10.1021/jo801366w.

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44

Jensen, Christel B., Niels G. Nørager, Anders S. Kristensen, and Kristian Strømgaard. "Illuminating Ionotropic Glutamate Receptors: Characterization of Fluorescent Antagonists Based on Polyamine Toxins." Biophysical Journal 104, no. 2 (January 2013): 272a. http://dx.doi.org/10.1016/j.bpj.2012.11.1524.

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45

Chenard, B. L., and F. S. Menniti. "Antagonists Selective for NMDA Receptors Containing the NR2B Subunit." Current Pharmaceutical Design 5, no. 5 (May 1999): 381–404. http://dx.doi.org/10.2174/138161280504230110102541.

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Abstract: In the late 1980s, a new class of N-methyl-D-aspartate (NMDA) receptor antagonists, exemplified by the phenylethanolamine ifenprodil (1), was identified. Initially, the mechanism of action of ifenprodil was a mystery as it was not a competitive antagonist at the glutamate or glycine (co-agonist) binding sites, nor was it a blocker of the calcium ion channel associated with the NMDA receptor. Early studies with a novel polyamine binding site associated with the NMDA receptor and functional studies in various brain regions suggested a unique and selective activity profile for 1. However, it was not until the NMDA receptor subunits were identified and expressed that ifenprodil was shown to be a selective antagonist for a subset of NMDA receptors containing the NR2B subunit. The wide range of potential therapeutic targets for NMDA antagonists coupled with the hope that NR2B selective agents might possess an improved clinical safety profile compared to non-selective compounds has supported an aggressive effort to develop the structure-activity relationships (SAR) of NR2B selective antagonists. This SAR and the basic physiology of the NMDA receptor form the basis of this review.

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46

Verdejo, Begoña, Mario Inclán, María Paz Clares, Irene Bonastre-Sabater, Mireia Ruiz-Gasent, and Enrique García-España. "Fluorescent Chemosensors Based on Polyamine Ligands: A Review." Chemosensors 10, no. 1 (December 22, 2021): 1. http://dx.doi.org/10.3390/chemosensors10010001.

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Polyamine ligands are water-soluble receptors that are able to coordinate, depending on their protonation degree, either metal ions, anionic, or neutral species. Furthermore, the presence of fluorescent signaling units allows an immediate visual response/signal. For these reasons, they can find applications in a wide variety of fields, mainly those where aqueous media is necessary, such as biological studies, wastewater analysis, soil contamination, etc. This review provides an overview of the recent developments in the research of chemosensors based on polyamine ligands functionalized with fluorescent signaling units. The discussion focuses on the design, synthesis, and physicochemical properties of this type of fluorescent chemosensors in order to analyze the applications associated to the sensing of metal ions, anions, and neutral molecules of environmental and/or biological interest. To facilitate a quick access and overview of all the chemosensors covered in this review, a summary table of the chemosensor structures and analytes, with all the corresponding references, is also presented.

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Andersen, Trine F., Denis B. Tikhonov, Ulrik Bølcho, Konstantin Bolshakov, Jared K. Nelson, Florentina Pluteanu, Ian R. Mellor, Jan Egebjerg, and Kristian Strømgaard. "Uncompetitive Antagonism of AMPA Receptors: Mechanistic Insights from Studies of Polyamine Toxin Derivatives." Journal of Medicinal Chemistry 49, no. 18 (September 2006): 5414–23. http://dx.doi.org/10.1021/jm060606j.

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48

TOMLINSON, SIMON R., SUZANNE KIRWIN, IAN MELLOR, JOHN HARRIS, MANJEET MUNDEY, MATTHEW BRIERLEY, DAVID R. BELL, and PETER N. R. USHERWOOD. "Interaction of a polyamine amide wasp toxin with cloned and mutant glutamate receptors." Biochemical Society Transactions 25, no. 3 (August 1, 1997): 551S. http://dx.doi.org/10.1042/bst025551s.

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49

Rodrı́guez, Laura, Sérgio Alves, João C. Lima, A. Jorge Parola, Fernando Pina, Conxa Soriano, Teresa Albelda, and Enrique Garcı́a-España. "Supramolecular interactions of hexacyanocobaltate(III) with polyamine receptors containing a terminal anthracene sensor." Journal of Photochemistry and Photobiology A: Chemistry 159, no. 3 (July 2003): 253–58. http://dx.doi.org/10.1016/s1010-6030(03)00173-4.

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50

MALDONADO C., María E., and Francis RAUL. "PRO-APOPTOTIC EFFECTS OF APPLE PROCYANIDINS IN HUMAN COLON CANCER CELLS AND THEIR DERIVED METASTATIC CELLS." Vitae 17, no. 3 (November 9, 2010): 337–47. http://dx.doi.org/10.17533/udea.vitae.7443.

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Apples are a rich source of Procyanidins (Pcy) which are able to inhibit colon carcinogenesis in animal models, but the mechanisms through which this occurs are not well understood.The evidence obtained in our laboratory and by other researchers, which shows that Pcy trigger apoptosis through different mechanisms in human colon adenocarcinoma SW480 cells and their derived metastatic SW620 cells is reviewed in this paper. In the apoptosis induced by Pcy, the polyamine metabolism is involved, but it is not present in SW480 cells. There is a differential sensitivity of both cells lines to the activation of TRAIL-death receptors. Pcy enhance the sensitivity of SW480 cells to TRAIL by activating the extrinsic apoptotic pathway, and overcome TRAIL-resistance in SW620 cells involving a cross-talk between the extrinsic and intrinsic pathways; and a Pcy-induced ROS production favoring mitochondria disruption. In addition, Pcy activate Fas receptor in SW480 cells, whereas SW620 cells are Fas-resistant despite the up-regulated Fas expression. Surprisingly, activation of the Fas receptor-mediated apoptosis by Pcy is observed in SW620 cells after inactivation of TRAIL-death receptors, suggesting that Fas-resistant phenotype may be associated with alterations in downstream events between TRAIL-death and Fas receptors. These data highlight the potential interest of apple Pcy in colon cancer prevention and therapy (combination therapy).

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