bims-polyam Biomed News
on Polyamines
Issue of 2020–02–02
ten papers selected by
Sebastian J. Hofer, University of Graz and Alexander Ivanov, Engelhardt Institute of Molecular Biology



  1. J Biol Chem. 2020 Jan 29. pii: jbc.RA119.011572. [Epub ahead of print]
      Snyder-Robinson syndrome (SRS) is an X-linked intellectual disability syndrome caused by a loss-of-function mutation in the spermine synthase (SMS) gene. Primarily affecting males, main manifestations of SRS include osteoporosis, hypotonic stature, seizures, cognitive impairment, and developmental delay. As there is no cure for SRS, treatment plans focus on alleviating symptoms rather than targeting the underlying causes. Biochemically, the cells of individuals with SRS accumulate excess spermidine, whereas spermine levels are reduced. We recently demonstrated that SRS patient-derived lymphoblastoid cells are capable of transporting exogenous spermine and its analogs into the cell and, in response, decrease excess spermidine pools to normal levels. However, dietary supplementation of spermine does not appear to benefit SRS patients or mouse models. Here, we investigated the potential use of a metabolically stable spermine mimetic, (R,R)-1,12-dimethylspermine (Me2SPM), to reduce the intracellular spermidine pools of SRS patient-derived cells. Me2SPM can functionally substitute for the native polyamines in supporting cell growth while stimulating polyamine homeostatic control mechanisms. We found that both lympho- and fibroblasts from SRS patients can accumulate Me2SPM, resulting in significantly decreased spermidine levels with no adverse effects on growth. Me2SPM administration to mice revealed that Me2SPM significantly decreases spermidine levels in multiple tissues. Importantly, Me2SPM was detectable in brain tissue, the organ most affected in SRS, and was associated with changes in polyamine metabolic enzymes. These findings indicate that the (R,R)-diastereomer of 1,12-Me2SPM represents a promising lead compound in developing a treatment aimed at targeting the molecular mechanisms underlying the SRS pathology.
    Keywords:  (R,R)-1,12-dimethylspermine (Me2SPM); Snyder-Robinson Syndrome; alpha-methylated polyamine; neurodevelopment; neurological disease; osteoporosis; polyamine; polyamine mimetic; spermidine; spermine synthase
    DOI:  https://doi.org/10.1074/jbc.RA119.011572
  2. Nature. 2020 Jan 29.
      ATP13A2 (PARK9) is a late endolysosomal transporter that is genetically implicated in a spectrum of neurodegenerative disorders, including Kufor-Rakeb syndrome-a parkinsonism with dementia1-and early-onset Parkinson's disease2. ATP13A2 offers protection against genetic and environmental risk factors of Parkinson's disease, whereas loss of ATP13A2 compromises lysosomes3. However, the transport function of ATP13A2 in lysosomes remains unclear. Here we establish ATP13A2 as a lysosomal polyamine exporter that shows the highest affinity for spermine among the polyamines examined. Polyamines stimulate the activity of purified ATP13A2, whereas ATP13A2 mutants that are implicated in disease are functionally impaired to a degree that correlates with the disease phenotype. ATP13A2 promotes the cellular uptake of polyamines by endocytosis and transports them into the cytosol, highlighting a role for endolysosomes in the uptake of polyamines into cells. At high concentrations polyamines induce cell toxicity, which is exacerbated by ATP13A2 loss due to lysosomal dysfunction, lysosomal rupture and cathepsin B activation. This phenotype is recapitulated in neurons and nematodes with impaired expression of ATP13A2 or its orthologues. We present defective lysosomal polyamine export as a mechanism for lysosome-dependent cell death that may be implicated in neurodegeneration, and shed light on the molecular identity of the mammalian polyamine transport system.
    DOI:  https://doi.org/10.1038/s41586-020-1968-7
  3. Biochim Biophys Acta Biomembr. 2020 Jan 28. pii: S0005-2736(20)30034-1. [Epub ahead of print] 183208
      The solute carrier 18 B1 (SLC18B1) is the most recently identified gene of the vesicular amine transporter family and is conserved in the animal kingdom from insects to humans. Proteoliposomes containing the purified human SLC18B1 protein transport not only monoamines, but also polyamines, such as spermidine (Spd) and spermine (Spm), using an electrochemical gradient of H+ established by vacuolar H+-ATPase (V-ATPase) as the driving force. SLC18B1 gene knockdown abolished the exocytosis of polyamines from mast cells, which affected the secretion of histamine. SLC18B1 gene knockout decreased polyamine levels by ~20% in the brain, and impaired short- and long-term memory. Thus, the SLC18B1 protein is responsible for the vesicular storage and release of polyamines, and functions as a vesicular polyamine transporter (VPAT). VPAT may define when, where, and how polyamine-mediated chemical transmission occurs, providing insights into the more versatile and complex features of amine-mediated chemical transmission than currently considered.
    Keywords:  Agmatine; Melatonin; Polyamine; SLC18B1; Spermidine and spermine; VPAT
    DOI:  https://doi.org/10.1016/j.bbamem.2020.183208
  4. J Clin Med. 2020 Jan 25. pii: E340. [Epub ahead of print]9(2):
      Diabetic retinopathy (DR) is a significant cause of blindness in working-age adults worldwide. Lack of effective strategies to prevent or reduce vision loss is a major problem. Since the degeneration of retinal neurons is an early event in the diabetic retina, studies to characterize the molecular mechanisms of diabetes-induced retinal neuronal damage and dysfunction are of high significance. We have demonstrated that spermine oxidase (SMOX), a mediator of polyamine oxidation is critically involved in causing neurovascular damage in the retina. The involvement of SMOX in diabetes-induced retinal neuronal damage is completely unknown. Utilizing the streptozotocin-induced mouse model of diabetes, the impact of the SMOX inhibitor, MDL 72527, on neuronal damage and dysfunction in the diabetic retina was investigated. Retinal function was assessed by electroretinography (ERG) and retinal architecture was evaluated using spectral domain-optical coherence tomography. Retinal cryosections were prepared for immunolabeling of inner retinal neurons and retinal lysates were used for Western blotting. We observed a marked decrease in retinal function in diabetic mice compared to the non-diabetic controls. Treatment with MDL 72527 significantly improved the ERG responses in diabetic retinas. Diabetes-induced retinal thinning was also inhibited by the MDL 72527 treatment. Our analysis further showed that diabetes-induced retinal ganglion cell damage and neurodegeneration were markedly attenuated by MDL 72527 treatment. These results strongly implicate SMOX in diabetes-induced retinal neurodegeneration and visual dysfunction.
    Keywords:  MDL 72527; diabetes; diabetic retinopathy; neurodegeneration; polyamine metabolism; retinal ganglion cells; spermine oxidase
    DOI:  https://doi.org/10.3390/jcm9020340
  5. Cell Metab. 2020 Jan 17. pii: S1550-4131(20)30001-2. [Epub ahead of print]
      Continual efferocytic clearance of apoptotic cells (ACs) by macrophages prevents necrosis and promotes injury resolution. How continual efferocytosis is promoted is not clear. Here, we show that the process is optimized by linking the metabolism of engulfed cargo from initial efferocytic events to subsequent rounds. We found that continual efferocytosis is enhanced by the metabolism of AC-derived arginine and ornithine to putrescine by macrophage arginase 1 (Arg1) and ornithine decarboxylase (ODC). Putrescine augments HuR-mediated stabilization of the mRNA encoding the GTP-exchange factor Dbl, which activates actin-regulating Rac1 to facilitate subsequent rounds of AC internalization. Inhibition of any step along this pathway after first-AC uptake suppresses second-AC internalization, whereas putrescine addition rescues this defect. Mice lacking myeloid Arg1 or ODC have defects in efferocytosis in vivo and in atherosclerosis regression, while treatment with putrescine promotes atherosclerosis resolution. Thus, macrophage metabolism of AC-derived metabolites allows for optimal continual efferocytosis and resolution of injury.
    Keywords:  arginase; arginine; atherosclerosis; atherosclerosis regression; efferocytosis; inflammation resolution; intracellular metabolism; macrophage; polyamines; putrescine
    DOI:  https://doi.org/10.1016/j.cmet.2020.01.001
  6. Res Microbiol. 2020 Jan 25. pii: S0923-2508(20)30014-0. [Epub ahead of print]
      Polyamines are small cationic amines required for modulating multiple cell process, including cell growth and DNA and RNA stability. In Salmonella polyamines are primarily synthesized from L-arginine or L-ornithine. Based on a previous study, which demonstrated that polyamines affect the expression of virulence gene in S. Typhimurium, we investigated the role of polyamines in the global gene and protein expression in S. Typhimurium. The depletion of polyamine biosynthesis led to down-regulation of genes encoding structural components of the Type Three Secretion system 1 (TTSS1) and its secreted effectors. Interestingly, Expression of HilA, which is the master regulator of Salmonella Pathogenicity Island 1 (SPI1), was only reduced at the post-transcriptional in the polyamine mutant. Enzymes related to biosynthesis and/or transport of several amino acids were up-regulated, just as the Mg2+-transport systems were three to six-fold up-regulated at both the transcriptional and protein levels. Furthermore, in the polyamine depletion mutant, proteins related to stress response (IbpA, Dps, SodB), were 2-5 fold up-regulated. Together our data provide strong evidence that polyamine depletion affects expression of proteins linked with virulence and stress response of S. Typhimurium. Furthermore, polyamines positively affected translation of HilA, the major regulator of SPI1.
    Keywords:  HilA translation; SPI1; putrescine; spermidine; stress; virulence
    DOI:  https://doi.org/10.1016/j.resmic.2019.12.001
  7. Plant Sci. 2020 Mar;pii: S0168-9452(19)31545-6. [Epub ahead of print]292 110372
      Polyamines (PAs) are small aliphatic amines with important regulatory activities in plants. Biotic stress results in changes in PA levels due to de novo synthesis and PA oxidation. In Arabidopsis thaliana five FAD-dependent polyamine oxidase enzymes (AtPAO1-5) participate in PA back-conversion and degradation. PAO activity generates H2O2, an important molecule involved in cell signaling, elongation, programmed cell death, and defense responses. In this work we analyzed the role of AtPAO genes in the Arabidopsis thaliana-Pseudomonas syringae pathosystem. AtPAO1 and AtPAO2 genes were transcriptionally up-regulated in infected plants. Atpao1-1 and Atpao2-1 single mutant lines displayed altered responses to Pseudomonas, and an increased susceptibility was found in the double mutant Atpao1-1 x Atpao2-1. These polyamine oxidases mutant lines showed disturbed contents of ROS (H2O2 and O2-) and altered activities of RBOH, CAT and SOD enzymes both in infected and control plants. In addition, changes in the expression levels of AtRBOHD, AtRBOHF, AtPRX33, and AtPRX34 genes were also noticed. Our data indicate an important role for polyamine oxidases in plant defense and ROS homeostasis.
    Keywords:  Arabidopsis thaliana-Pseudomonas syringae pathosystem; Hydrogen peroxide; Polyamine oxidases; RBOH enzymes; Spermine; Superoxide anion radical
    DOI:  https://doi.org/10.1016/j.plantsci.2019.110372
  8. Food Sci Nutr. 2020 Jan;8(1): 675-682
      Soybean seeds contain phytochemicals such as polyamines and isoflavones, which have been identified as functional components mediating health benefits in association with the consumption of soy foods. While a clear picture of the spatial distribution of these components within the seed is lacking, such information would be important to enhance or reduce their concentration in respective foods through processing. Thus, the objective of the present study was to visualize the most relevant components with respect to their distribution in soybean seeds. Mature soybean seeds were subject to atmospheric-pressure scanning-microprobe matrix-assisted laser desorption/ionization (AP-SMALDI) combined with a Fourier-transform orbital trapping mass spectrometer to generate high-resolution chemical images of phytochemical distribution. Based on seed cross sections, differential distributions of functional components were found between soybean cotyledon and germ (shoot, hypocotyl, root) regions. Spermidine and spermine were present in higher concentrations in the germ rather than in cotyledons with highest concentrations in root and shoot meristem tissues. Differential concentrations of spermidine and other components between the germ and cotyledon regions were confirmed by seed fractioning. In contrast to polyamines spermidine and spermine, the different types of daidzein, glycitein, and genistein isoflavones were all visualized in root parenchyma tissue exclusively. Overall, mass spectrometry imaging of soybean seeds revealed clear insights into the differential distribution of functional phytochemicals. Based on their distribution and depending on specific needs, spermidine and isoflavones can either be enriched or reduced during food processing by separating cotyledon and germ fractions.
    Keywords:  Isoflavones; mass spectrometry imaging; polyamines; soybean; spermidine
    DOI:  https://doi.org/10.1002/fsn3.1356
  9. Appl Environ Microbiol. 2020 Jan 31. pii: AEM.00030-20. [Epub ahead of print]
      The siderophore synthetic system in Shewanella species is able to synthesize dozens of macrocyclic siderophores in vitro with synthetic precursors. In vivo, however, although three siderophores are produced naturally in S. algae B516 which carries a lysine decarboxylase (AvbA) specific for siderophore synthesis, only one siderophore can be detected from many other Shewanella species. In this study, we examined a siderophore-overproducing mutant of S. oneidensis, which lacks an AvbA counterpart, and found that it can also produce these three siderophores. We identified both SpeC and SpeF as promiscuous decarboxylases for both lysine and ornithine to synthesize siderophore precursors cadaverine and putrescine respectively. Intriguingly, putrescine is mainly synthesized from arginine through an arginine decarboxylation pathway in a constitutive manner, not liable to the concentrations of iron and siderophores. Our results provide further evidence that the substrate availability plays a determining role in siderophore production. Furthermore, we provide evidence to suggest that under iron starvation conditions, cells allocate more putrescine for siderophore biosynthesis by down-regulating expression of the enzyme that transforms putrescine into spermidine. Overall, this study provides another example of the great flexibility of bacterial metabolism that is honed by evolution to better fit living environments of these bacteria.Importance The simultaneous production of multiple siderophores is considered a general strategy for microorganisms to rapid adapt to their ever-changing environments. In this study, we show that some Shewanella may downscale their capability of siderophore synthesis to facilitate adaptation. Although S. oneidensis lacks an enzyme specifically synthesizing cadaverine, it can produce it by using promiscuous ornithine decarboxylases. Despite the ability, this bacterium predominately produces the primary siderophore while restraining production of secondary siderophores by regulating substrate availability. In addition to use the ADC pathway for putrescine synthesis, cells optimize the putrescine pool for siderophore production. Our work provides an insight into coordinated synthesis of multiple siderophores by harnessing promiscuous enzymes in bacteria and underscores the importance of substrate pools for biosynthesis of natural products.
    DOI:  https://doi.org/10.1128/AEM.00030-20
  10. Front Microbiol. 2019 ;10 2928
      Inappropriate use of antibiotics favors the selection and spread of resistant bacteria. To reduce the spread of these bacteria, finding new molecules with activity is urgent and necessary. Several polyamine analogs have been constructed and used to control microorganisms and tumor cells. Mygalin is a synthetic acylpolyamine, which are analogs of spermidine, derived from the hemolymph of the spider Acanthoscurria gomesiana. The effective activity of polyamines and their analogs has been associated with their structure. The presence of two acyl groups in the Mygalin structure may give this molecule a specific antibacterial activity. The aim of this study was to identify the mechanisms involved in the interaction of Mygalin with Escherichia coli to clarify its antimicrobial action. The results indicated that Mygalin exhibits intense dose and time-dependent bactericidal activity. Treatment of E. coli with this molecule caused membrane rupture, inhibition of DNA synthesis, DNA damage, and morphological changes. The esterase activity increased along with the intracellular production of reactive oxygen species (ROS) after treatment of the bacteria with Mygalin. In addition, this molecule was able to sequester iron and bind to LPS. We have shown that Mygalin has bactericidal activity with underlying mechanisms involving ROS generation and chelation of iron ions that are necessary for bacterial metabolism, which may contribute to its microbicidal activity. Taken together, our data suggest that Mygalin can be explored as a new alternative drug with antimicrobial potential against Gram-negative bacteria or other infectious agents.
    Keywords:  E. coli; Mygalin; acylpolyamine; antimicrobial; biomolecule; oxidative stress
    DOI:  https://doi.org/10.3389/fmicb.2019.02928