bims-polyam Biomed News
on Polyamines
Issue of 2020‒11‒29
seven papers selected by
Alexander Ivanov
Engelhardt Institute of Molecular Biology

  1. Proc Natl Acad Sci U S A. 2020 Nov 23. pii: 201922342. [Epub ahead of print]
    Vrijsen S, Besora-Casals L, van Veen S, Zielich J, Van den Haute C, Hamouda NN, Fischer C, Ghesquière B, Tournev I, Agostinis P, Baekelandt V, Eggermont J, Lambie E, Martin S, Vangheluwe P.
      Recessive loss-of-function mutations in ATP13A2 (PARK9) are associated with a spectrum of neurodegenerative disorders, including Parkinson's disease (PD). We recently revealed that the late endo-lysosomal transporter ATP13A2 pumps polyamines like spermine into the cytosol, whereas ATP13A2 dysfunction causes lysosomal polyamine accumulation and rupture. Here, we investigate how ATP13A2 provides protection against mitochondrial toxins such as rotenone, an environmental PD risk factor. Rotenone promoted mitochondrial-generated superoxide (MitoROS), which was exacerbated by ATP13A2 deficiency in SH-SY5Y cells and patient-derived fibroblasts, disturbing mitochondrial functionality and inducing toxicity and cell death. Moreover, ATP13A2 knockdown induced an ATF4-CHOP-dependent stress response following rotenone exposure. MitoROS and ATF4-CHOP were blocked by MitoTEMPO, a mitochondrial antioxidant, suggesting that the impact of ATP13A2 on MitoROS may relate to the antioxidant properties of spermine. Pharmacological inhibition of intracellular polyamine synthesis with α-difluoromethylornithine (DFMO) also increased MitoROS and ATF4 when ATP13A2 was deficient. The polyamine transport activity of ATP13A2 was required for lowering rotenone/DFMO-induced MitoROS, whereas exogenous spermine quenched rotenone-induced MitoROS via ATP13A2. Interestingly, fluorescently labeled spermine uptake in the mitochondria dropped as a consequence of ATP13A2 transport deficiency. Our cellular observations were recapitulated in vivo, in a Caenorhabditis elegans strain deficient in the ATP13A2 ortholog catp-6 These animals exhibited a basal elevated MitoROS level, mitochondrial dysfunction, and enhanced stress response regulated by atfs-1, the C. elegans ortholog of ATF4, causing hypersensitivity to rotenone, which was reversible with MitoTEMPO. Together, our study reveals a conserved cell protective pathway that counters mitochondrial oxidative stress via ATP13A2-mediated lysosomal spermine export.
    Keywords:  P5B-type ATPase; antioxidant; mitochondria; neurodegeneration; polyamine transport
  2. Brain Res Bull. 2020 Nov 23. pii: S0361-9230(20)30701-2. [Epub ahead of print]
    Aglawe MM, Kale MB, Rahangdale SR, Kotagale NR, Umekar MJ, Taksande BG.
      Chronic maternal ethanol exposure leads to poor intelligence, impaired cognition and array of neurological symptoms in offsprings and commonly referred as fetal alcohol spectrum disorder (FASD). Despite high prevalence and severity, the neurochemical basis of FASD remains largely unexplored. The present study evaluated the pharmacological effects of agmatine in cognitive deficits associated with FAS in rat's offsprings prenatally exposed to alcohol. Pregnant rats received ethanol in liquid modified diet during the entire gestational period of 21 days. Offsprings were treated with agmatine (20 - 80 mg/Kg, i.p.) during early postnatal days (PND: 21-35) and subsequently evaluated for anxiety in elevated plus maze (EPM), depression in forced swim test (FST) and learning and memory in Morris's water maze (MWM) during post adolescent phase. Hippocampal agmatine, BDNF, TNF-α and IL-6 levels were also analyzed in prenatally ethanol exposed pups. Offsprings prenatally exposed to ethanol demonstrated delayed righting reflex, reduced exploratory behavior along with anxiety, depression-like behavior and impaired memory. These behavioral abnormalities were correlated with a significant reduction in hippocampal agmatine and BDNF levels and elevation in TNF-α and IL-6 immunocontent. Chronic agmatine (40 and 80 mg/Kg, i.p.) administration for 15 days (PND: 21-35), improved entries and time spent in open arm of EPM, decreased immobility time in FST. It also reduced latency to reach the platform location; increased the number of entries, time spent in platform quadrant and also number of crossing over platform quadrant when subjected to MWM test in prenatally ethanol exposed offsprings. This study provides functional evidences for the therapeutic potential of agmatine in cognitive impairment and other neurological complications associated with FASD.
    Keywords:  Agmatine; Anxiety; Depression; Fetal alcohol syndrome; Memory impairment
  3. Onco Targets Ther. 2020 ;13 11697-11709
    Zeng Z, Lan J, Lei S, Yang Y, He Z, Xue Y, Chen T.
      Purpose: Previously, we showed that lactate promoted the proliferation and mobility of hepatocellular carcinoma (HCC) cells by increasing the expression of ornithine decarboxylase 1 (ODC1). In this study, we determined the relationship between ODC1 and pyruvate kinase M2 (PKM2, a key lactate metabolism enzyme), and determined the combined effects of difluoromethylornithine (DFMO; an ODC1 inhibitor) and compound 3k (a PKM2 inhibitor) on HCC cells.Methods: First, the relationship between PKM2 and ODC1 was analyzed using Western blotting, Cell Counting Kit (CCK)-8 assays, transwell assays, bioinformatics, quantitative real-time fluorescent PCR (qRT-PCR), and immunohistochemical staining. Thereafter, the ODC1 inhibitor DFMO and the PKM2 inhibitor compound 3k were employed. Their combined effects on HCC cell proliferation and mobility were evaluated via CCK-8 assay, flow cytometry, a subcutaneous xenograft tumor model in mice, wound healing assays, and transwell assays. Additionally, the effects of DFMO and compound 3k on the epithelial-mesenchymal transition phenotype and the AKT/GSK-3β/β-catenin pathway were explored using Western blotting and immunofluorescence.
    Results: PKM2 knockdown significantly decreased the ODC1 expression, and the proliferation and invasion of HCC cells, while ODC1 overexpression reversed the inhibitory effects of PKM2 knockdown. Similarly, inhibition of ODC1 also decreased the expression of PKM2 via reducing the c-myc-induced transcription. PKM2 was co-expressed with ODC1 in HCC samples, while simultaneously upregulated PKM2 and ODC1 led to the poorest survival outcome. DFMO and compound 3k synergistically inhibited HCC cell proliferation, induced apoptosis, and suppressed cell mobility, as well as the EMT phenotype and the AKT/GSK-3β/β-catenin pathway. The AKT activator SC79 reversed the inhibitory effects.
    Conclusion: PKM2/ODC1 are involved in a positive feedback loop. The simultaneous inhibition of ODC1 and PKM2 using DFMO and compound 3k exerts synergistic effects against HCC cells via the AKT/GSK-3β/β-catenin pathway. Thus, DFMO combined with compound 3k may be a novel effective strategy for treating HCC.
    Keywords:  DFMO; compound 3k; hepatocellular carcinoma; ornithine decarboxylase 1; pyruvate kinase M2; synergistic effect
  4. Mol Plant. 2020 Nov 18. pii: S1674-2052(20)30386-5. [Epub ahead of print]
    Lv Y, Shao G, Jiao G, Sheng Z, Xie L, Hu S, Tang S, Wei X, Hu P.
      Under conditions of labor or resource scarcity, direct seeding, rather than transplantation, is a preferred mode of rice (Oryza sativa. L) cultivation. This approach requires varieties that exhibit uniform seedling emergence. Mesocotyl elongation (ME), the main driver of rice seedling rapid emergence from soil, is enhanced by darkness and inhibited by light. Plant polyamine oxidases (PAOs) oxidate polyamines (PAs) and release H2O2. Here, we established that OsPAO5 expression in rice seedlings is increased in the presence of light, and inhibited by darkness. To determine its role in ME, we created OsPAO5 mutants using CRISPR/Cas9. Compared with the wild type, pao5 mutants had longer mesocotyls, released less H2O2, and synthesized more ethylene. The mutant seedlings emerged at a higher and more uniform rate, indicating potential use in direct seeding. Nucleotide polymorphism analysis revealed that an SNP variation (PAO5-578G/A) in the 578 bp upstream of OsPAO5 start codon alters its expression, which is further selected during rice mesocotyl domestication. The PAO5-578G genotype consisting with long mesocotyl mainly exists in wild rice, most Aus and some Geng (Japonica) accessions. Intriguingly, knocking out of OsPAO5 can remarkably increase the grain weight, grain numbers and yield potential. In summary, we developed a novel strategy to obtain elite rice with higher emergence vigor and yield potential, which can be conveniently and widely used to breed varieties of direct-seeding rice.
    Keywords:  Oryza sativa. L; direct-seeding; grain yield; mesocotyl elongation; polyamine oxidase 5
  5. Biomed Environ Sci. 2020 Oct 20. 33(10): 750-759
    Wang YM, Wang WY, Sun LY, Li Q, Zhao ZJ, Hu J, Zhang RY, Wang LH.
      Objective: To explore potential serum biomarkers of children with Kashin-Beck Disease (KBD) and the metabolic pathways to which the biomarkers belong.Methods: A two-stage metabolomic study was employed. The discovery cohort included 56 patients, 51 internal controls, and 50 external controls. The metabolites were determined by HPLC-(Q-TOF)-MS and confirmed by Human Metabolome Databases (HMDB) and Metlin databases. MetaboAnalyst 3.0 and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database were used to analyze the metabolic pathways of the candidate metabolites. The use of HPLC-(Q-TRAP)-MS enabled quantitative detection of the target metabolites which were chosen using the discovery study and verified in another independent verification cohort of 31 patients, 41 internal controls, and 50 external controls.
    Results: Eight candidate metabolites were identified out in the discovery study, namely kynurenic acid, N-α-acetylarginine, 6-hydroxymelatonin, sphinganine, ceramide, sphingosine-1P, spermidine, and glycine. These metabolites exist in sphingolipid, glutathione, and tryptophan metabolic pathways. In the second-stage study, five candidate metabolites were validated, including kynurenic acid, N-α-acetylarginine, sphinganine, spermidine, and sphingosine-1P. Except for spermidine, all substances exhibited low expression in the case group compared with the external control group, and the difference in levels of sphinganine, spermidine, and sphingosine-1P was statistically significant.
    Conclusion: The direction of change of levels of sphinganine, spermidine, and sphingosine-1P in the two-stage study cohorts was completely consistent, and the differences were statistically significant. Therefore, these substances can be used as potential biomarkers of KBD. Furthermore, these results raise the possibility that sphingolipid metabolic pathways may be closely related to KBD.
    Keywords:  Kashin-Beck disease; Metabolism pathways; Potential biomarkers; Serum
  6. Eur J Pharmacol. 2020 Nov 18. pii: S0014-2999(20)30831-1. [Epub ahead of print] 173739
    Rahangdale S, Fating R, Gajbhiye M, Kapse M, Inamdar N, Kotagale N, Umekar M, Taksande B.
      3-Hydroxy-3-methyl-glutaryl-co-enzyme-A (HMG-CoA) reductase inhibitors (statins) are popularly used for the treatment of obesity and hypercholesterolemia with established safety profile. Statins exhibits a wide range of neurobehavioral effects in addition to their peripheral actions, and may be beneficial in treatment of psychiatric conditions. Present study investigated the role of agmatine and imidazoline receptors in antidepressant-like effect of statins in mouse forced swimming test (FST). The antidepressant-like effect of atorvastatin (5 mg/kg, p.o.) and simvastatin (10 mg/kg, p.o.) was potentiated by pretreatment with agmatine (5 mg/kg, i.p.) as well as the drugs known to increase endogenous agmatine levels in brain viz., L-arginine (40 μg/mouse, i.c.v.), an agmatine biosynthetic precursor; arcaine (50 μg/mouse, i.c.v), agmatinase inhibitor; and aminoguanidine (6.5 μg/mouse, i.c.v.), a diamine oxidase inhibitor. Further, both the statins increased agmatine levels within hippocampus and prefrontal cortex. Conversely, prior administration of I1 receptor antagonist, efaroxan (1 mg/kg, i.p.) and I2 receptor antagonist, idazoxan (0.25 mg/kg, i.p.) blocked the antidepressant-like effect of statins and their synergistic combination with agmatine. These results demonstrate the involvement of agmatine and imidazoline receptors in antidepressant-like effect of statins and suggest as a potential therapeutic target for the treatment of depressive disorders.
    Keywords:  Agmatine; Depression; FST; HMG-CoA reductase inhibitors; Imidazoline receptors; Statins
  7. Biomolecules. 2020 Nov 20. pii: E1579. [Epub ahead of print]10(11):
    Alfarhan M, Jafari E, Narayanan SP.
      Diabetic retinopathy (DR) is the leading cause of vision loss among working-age adults. Extensive evidences have documented that oxidative stress mediates a critical role in the pathogenesis of DR. Acrolein, a product of polyamines oxidation and lipid peroxidation, has been demonstrated to be involved in the pathogenesis of various human diseases. Acrolein's harmful effects are mediated through multiple mechanisms, including DNA damage, inflammation, ROS formation, protein adduction, membrane disruption, endoplasmic reticulum stress, and mitochondrial dysfunction. Recent investigations have reported the involvement of acrolein in the pathogenesis of DR. These studies have shown a detrimental effect of acrolein on the retinal neurovascular unit under diabetic conditions. The current review summarizes the existing literature on the sources of acrolein, the impact of acrolein in the generation of oxidative damage in the diabetic retina, and the mechanisms of acrolein action in the pathogenesis of DR. The possible therapeutic interventions such as the use of polyamine oxidase inhibitors, agents with antioxidant properties, and acrolein scavengers to reduce acrolein toxicity are also discussed.
    Keywords:  acrolein; diabetic retinopathy; oxidative stress; polyamine oxidation; vision