bims-polyam Biomed News
on Polyamines
Issue of 2020‒05‒03
seven papers selected by
Alexander Ivanov
Engelhardt Institute of Molecular Biology

  1. Oncogene. 2020 Apr 29.
    Sierra JC, Piazuelo MB, Luis PB, Barry DP, Allaman MM, Asim M, Sebrell TA, Finley JL, Rose KL, Hill S, Holshouser SL, Casero RA, Cleveland JL, Woster PM, Schey KL, Bimczok D, Schneider C, Gobert AP, Wilson KT.
      Helicobacter pylori infection is the main risk factor for the development of gastric cancer, the third leading cause of cancer death worldwide. H. pylori colonizes the human gastric mucosa and persists for decades. The inflammatory response is ineffective in clearing the infection, leading to disease progression that may result in gastric adenocarcinoma. We have shown that polyamines are regulators of the host response to H. pylori, and that spermine oxidase (SMOX), which metabolizes the polyamine spermine into spermidine plus H2O2, is associated with increased human gastric cancer risk. We now used a molecular approach to directly address the role of SMOX, and demonstrate that Smox-deficient mice exhibit significant reductions of gastric spermidine levels and H. pylori-induced inflammation. Proteomic analysis revealed that cancer was the most significantly altered functional pathway in Smox-/- gastric organoids. Moreover, there was also less DNA damage and β-catenin activation in H. pylori-infected Smox-/- mice or gastric organoids, compared to infected wild-type animals or gastroids. The link between SMOX and β-catenin activation was confirmed in human gastric organoids that were treated with a novel SMOX inhibitor. These findings indicate that SMOX promotes H. pylori-induced carcinogenesis by causing inflammation, DNA damage, and activation of β-catenin signaling.
  2. J Gen Physiol. 2020 Jul 06. pii: e201912527. [Epub ahead of print]152(7):
    Suma A, Granata D, Thomson AS, Carnevale V, Rothberg BS.
      Polyamines such as spermidine and spermine are found in nearly all cells, at concentrations ranging up to 0.5 mM. These cations are endogenous regulators of cellular K+ efflux, binding tightly in the pores of inwardly rectifying K+ (Kir) channels in a voltage-dependent manner. Although the voltage dependence of Kir channel polyamine blockade is thought to arise at least partially from the energetically coupled movements of polyamine and K+ ions through the pore, the nature of physical interactions between these molecules is unclear. Here we analyze the polyamine-blocking mechanism in the model K+ channel MthK, using a combination of electrophysiology and computation. Spermidine (SPD3+) and spermine (SPM4+) each blocked current through MthK channels in a voltage-dependent manner, and blockade by these polyamines was described by a three-state kinetic scheme over a wide range of polyamine concentrations. In the context of the scheme, both SPD3+ and SPM4+ access a blocking site with similar effective gating valences (0.84 ± 0.03 e0 for SPD3+ and 0.99 ± 0.04 e0 for SPM4+), whereas SPM4+ binds in the blocked state with an ∼20-fold higher affinity than SPD3+ (Kd = 28.1 ± 3.1 µM for SPD3+ and 1.28 ± 0.20 µM for SPM4+), consistent with a free energy difference of 1.8 kcal/mol. Molecular simulations of the MthK pore in complex with either SPD3+ or SPM4+ are consistent with the leading amine interacting with the hydroxyl groups of T59, at the selectivity filter threshold, with access to this site governed by outward movement of K+ ions. These coupled movements can account for a large fraction of the voltage dependence of blockade. In contrast, differences in binding energetics between SPD3+ and SPM4+ may arise from distinct electrostatic interactions between the polyamines and carboxylate oxygens on the side chains of E92 and E96, located in the pore-lining helix.
  3. Biochim Biophys Acta Biomembr. 2020 Apr 24. pii: S0005-2736(20)30128-0. [Epub ahead of print] 183297
    Li J, Beuerman R, Verma CS.
      Naturally occurring linear polyamines are known to enable bacteria to be resistant to cationic membrane active peptides. To understand this protective mechanism, molecular dynamics simulations are employed to probe their effect on a model bacterial outer membrane. Being protonated at physiological pH, the amine groups of the polyamine engage in favorable electrostatic interactions with the negatively charged phosphate groups of the membrane. Additionally, the amine groups form large number of hydrogen bonds with the phosphate groups. At high concentrations, these hydrogen bonds and the electrostatic network can non-covalently crosslink the lipid A molecules, resulting in stabilization of the outer membrane against membrane active antibiotics such as colistin and polymyxin B. Moreover, large polyamine molecules (e.g., spermidine) have a stronger stabilization effect than small polyamine molecules (e.g., ethylene diamine). The atomistic insights provide useful guidance for the design of next generation membrane active amine-rich antibiotics, especially to tackle the growing threat of multi-drug resistance of Gram negative bacteria.
    Keywords:  Bacterial outer membrane; Colistin; Lipid A; Low molecular weight linear polyamine; Molecular dynamics simulations; Polymyxin B
  4. Brain Res Bull. 2020 Apr 25. pii: S0361-9230(19)30974-8. [Epub ahead of print]
    Kotagale N, Deshmukh R, Dixit M, Fating R, Umekar M, Taksande B.
      Extensive clinical and experimental studies established that depression and mood disorders are highly prevalent neuropsychiatric conditions in Alzheimer's disease (AD). However, its neurochemical basis is not clearly understood. Thus, understanding the neural mechanisms involved in mediating the co-morbidity of depression and AD may be crucial in exploring new pharmacological treatments for this condition. The present study investigated the role of the agmatinergic system in β-amyloid (Aβ1-42) peptide-induced depression using forced swim test (FST) in mice. Following the 28th days of its administration, Aβ1-42 peptide produced depression-like behavior in mice as evidenced by increased immobility time in FST and increased expression of pro-inflammatory cytokines like IL-6 and TNF-α compared to the control animals. The Aβ1-42 peptide-induced depression and neuroinflammatory markers were significantly inhibited by agmatine (20-40 µg/rat, i.c.v.), moxonidine (50 µg/rat, i.c.v.), 2-BFI (20 µg/rat, i.c.v.), L-arginine (80 µg/rat, i.c.v.) by once-daily administration during day 8 - 27 of the protocol. The antidepressant-like effect of agmatine in Aβ1-42 peptide in mice was potentiated by imidazoline receptor I1 agonist, moxonidine (25 µg/rat, i.c.v.) and imidazoline receptor I2 agonist 2-BFI (10 µg/rat, i.c.v.) at their sub-effective doses. On the other hand, it was completely blocked by imidazoline receptor I1 antagonist, efaroxan (10 µg/rat, i.c.v.) and imidazoline receptor I2 antagonist, idazoxan (4 µg/rat, i.c.v.). Also, agmatine levels were significantly reduced in brain samples of β-amyloid injected mice as compared to the control animals. In conclusion, the present study suggests the importance of endogenous agmatinergic system and imidazoline receptors system in β-amyloid induced a depressive-like behavior in mice. The data projects agmatine as a potential therapeutic target for the AD-associated depression and comorbidities.
    Keywords:  Agmatine; Alzheimer’s diseases; depression; ethanol; imidazoline receptors; β-amyloid
  5. Plant Direct. 2020 May;4(5): e00217
    Mo A, Xu T, Bai Q, Shen Y, Gao F, Guo J.
      Polyamines are important for non-climacteric fruit ripening according to an analysis of the model plant strawberry. However, the molecular mechanism underlying the polyamine accumulation during ripening has not been fully elucidated. In this study, an examination of our proteome data related to strawberry fruit ripening revealed a putative polyamine oxidase 5, FaPAO5, which was localized in the cytoplasm and nucleus. Additionally, FaPAO5 expression levels as well as the abundance of the encoded protein continually decreased during ripening. Inhibiting FaPAO5 expression by RNAi promoted Spd, Spm, and ABA accumulation while inhibited H2O2 production, which ultimately enhanced ripening as evidenced by the ripening-related events and corresponding gene expression changes. The opposite effects were observed in FaPAO5-overexpressing transgenic fruits. Analyses of the binding affinity and enzymatic activity of FaPAO5 with Spm, Spd, and Put uncovered a special role for FaPAO5 in the terminal catabolism of Spm and Spd, with a K d of 0.21 and 0.29 µM, respectively. Moreover, FaPAO5 expression was inhibited by ABA and promoted by Spd and Spm. Furthermore, the RNA-seq analysis of RNAi and control fruits via differentially expressed genes (DEGs) indicated the six most enriched pathways among the differentially expressed genes were related to sugar, abscisic acid, ethylene, auxin, gibberellin, and Ca2+. Among four putative PAO genes in the strawberry genome, only FaPAO5 was confirmed to influence fruit ripening. In conclusion, FaPAO5 is a negative regulator of strawberry fruit ripening and modulates Spm/Spd levels as a signaling event, in which ABA plays a central role.
    Keywords:  ABA; FaPAO5; polyamine; strawberry fruit ripening
  6. J Pharm Biomed Anal. 2020 Apr 05. pii: S0731-7085(20)30052-2. [Epub ahead of print]186 113294
    Maráková K, Piešťanský J, Zelinková Z, Mikuš P.
      Biogenic amines (BA) are a broad group of biologically active substances, the presence of which in the human body can provide important diagnostic information for many various pathologies, including chronic inflammation. In this work, a capillary electrophoresis (CE) hyphenated with tandem mass spectrometry (MS/MS) method was developed for the simultaneous determination of twelve BA (histamine, serotonin, dopamine, norepinephrine, epinephrine, putrescine, cadaverine, spermine, spermidine, tyramine, tryptamine, phenylethylamine) in human urine as potential biomarkers of inflammatory bowel diseases (IBD). The electrophoretic separations were carried out in an uncoated fused silica capillary (I.D. 50 μm) using 50 mM formic acid (pH 2.0) as a background electrolyte. A reliable identification of the analytes was based on the combination of time resolution in CE and mass resolution in triple quadrupole MS/MS. The total analysis time of the proposed CEMS/MS method was less than 10 min with the limits of detection in the range of 4.47-144 ng/mL. The intra- and inter-day accuracy ranged in the intervals 89.75-109.4% and 89.99-110.2%, respectively, with the RSD values for the intra- and inter-day precision lower than 14 and 13 %, respectively. The recovery values for the samples spiked at three concentration levels ranged from 81.73-105.6% with a precision not exceeding 9.9 %. The favorable performance parameters of the CEMS/MS method highlighted its usefulness for routine clinical applications. In this work, the CEMS/MS method was applied, for the first time, to the analytical profiling of the BA in clinical human samples. The obtained results showed a statistically significant decrease of serotonin and norepinephrine, and an increase of histamine and spermidine, in the studied group of IBD patients when compared with the control group. These findings could be utilized in studying and clarifying the mechanisms of IBD or relevant therapy.
    Keywords:  Capillary electrophoresis; Catecholamines; Crohn’s disease; Histamine; Polyamines; Triple quadrupole mass spectrometry
  7. Metabolites. 2020 Apr 24. pii: E168. [Epub ahead of print]10(4):
    Ioannou GN, Nagana Gowda GA, Djukovic D, Raftery D.
      Nonalcoholic fatty liver disease (NAFLD) is categorized based on histological severity into nonalcoholic fatty liver (NAFL) or nonalcoholic steatohepatitis (NASH). We used a multiplatform metabolomics approach to identify metabolite markers and metabolic pathways that distinguish NAFL from early NASH and advanced NASH. We analyzed fasting serum samples from 57 prospectively-recruited patients with histologically-proven NAFLD, including 12 with NAFL, 31 with early NASH and 14 with advanced NASH. Metabolite profiling was performed using a combination of liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR) spectroscopy analyzed with multivariate statistical and pathway analysis tools. We targeted 237 metabolites of which 158 were quantified. Multivariate analysis uncovered metabolite profile clusters for patients with NAFL, early NASH, and advanced NASH. Also, multiple individual metabolites were associated with histological severity, most notably spermidine which was more than 2-fold lower in advanced fibrosis vs. early fibrosis, in advanced NASH vs. NAFL and in advanced NASH vs. early NASH, suggesting that spermidine exercises a protective effect against development of fibrosing NASH. Furthermore, the results also showed metabolic pathway perturbations between early-NASH and advanced-NASH. In conclusion, using a combination of two reliable analytical platforms (LC-MS and NMR spectroscopy) we identified individual metabolites, metabolite clusters and metabolic pathways that were significantly different between NAFL, early-NASH, and advanced-NASH. These differences provide mechanistic insights as well as potentially important metabolic biomarker candidates that may noninvasively distinguish patients with NAFL, early-NASH, and advanced-NASH. The associations of spermidine levels with less advanced histology merit further assessment of the potential protective effects of spermidine in NAFLD.
    Keywords:  liquid chromatography-mass spectrometry; metabolic pathway; nonalcoholic fatty liver; nonalcoholic steatohepatitis; nuclear magnetic resonance spectroscopy