Specificity of mammalian spermidine synthase and spermine synthase.
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ABSTRACT:
SUBMITTER: Pegg AE
PROVIDER: S-EPMC1163129 | biostudies-other | 1981 Aug
REPOSITORIES: biostudies-other
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Project description:1. S-Adenosyl-l-methionine, S-adenosyl-l-homocysteine, 5'-methylthioadenosine and a number of analogues having changes in the base, sugar or amino acid portions of the molecule were tested as potential inhibitors of spermidine synthase and spermine synthase from rat ventral prostate. 2. S-Adenosyl-l-methionine was inhibitory to these reactions, as were other nucleosides containing a sulphonium centre. The most active of these were S-adenosyl-l-ethionine, S-adenosyl-4-methylthiobutyric acid, S-adenosyl-d-methionine and S-tubercidinylmethionine, which were all comparable in activity with S-adenosylmethionine itself, producing 70-98% inhibition at 1mm concentrations. Spermine synthase was somewhat more sensitive than spermidine synthase. 3. 5'-Methylthioadenosine, 5'-ethylthioadenosine and 5'-methylthiotubercidin were all powerful inhibitors of both enzymes, giving 50% inhibition of spermine synthase at 10-15mum and 50% inhibition of spermidine synthase at 30-45mum. 4. S-Adenosyl-l-homocysteine was a weak inhibitor of spermine synthase and practically inactive against spermidine synthase. Analogues of S-adenosylhomocysteine lacking either the carboxy or the amino group of the amino acid portion were somewhat more active, as were derivatives in which the ribose ring had been opened by oxidation. The sulphoxide and sulphone derivatives of decarboxylated S-adenosyl-l-homocysteine and the sulphone of S-adenosyl-l-homocysteine were quite potent inhibitors and were particularly active against spermidine synthase (giving 50% inhibition at 380, 50 and 20mum respectively). 5. These results are discussed in terms of the possible regulation of polyamine synthesis by endogenous nucleosides and the possible value of some of the inhibitory substances in experimental manipulations of polyamine concentrations. It is suggested that 5'-methylthiotubercidin and the sulphone of S-adenosylhomocysteine or of S-adenosyl-3-thiopropylamine may be particularly valuable in this respect.
| S-EPMC1161808 | biostudies-other
Project description:The naturally occurring polyamines putrescine, spermidine or spermine are ubiquitous in all cells. Although polyamines have prominent regulatory roles in cell division and growth, precise molecular and cellular functions are not well-established in vivo. In this work we have performed microarray experiments with a spermidine synthase, spermine oxidase mutant (Deltaspe3 Deltafms1) strain to investigate the responsiveness of yeast genes to supplementation with spermidine or spermine. Expression analysis identified genes responsive to the addition of either excess spermidine (10(-5) M) or spermine (10(-5) M) compared to a control culture containing 10(-8) M spermidine. 247 genes were upregulated > two-fold and 11 genes were upregulated >10-fold after spermidine addition. Functional categorization of the genes showed induction of transport-related genes and genes involved in methionine, arginine, lysine, NAD and biotin biosynthesis. 268 genes were downregulated more than two-fold, and six genes were downregulated > eight-fold after spermidine addition. A majority of the downregulated genes are involved in nucleic acid metabolism and various stress responses. In contrast, only a few genes (18) were significantly responsive to spermine. Thus, results from global gene expression profiling demonstrate a more major role for spermidine in modulating gene expression in yeast than spermine.
| S-EPMC3490486 | biostudies-literature
Project description:Spermine is present in many organisms including animals, plants, some fungi, some archaea, and some bacteria. It is synthesized by spermine synthase, a highly specific aminopropyltransferase. This review describes spermine synthase structure, genetics, and function. Structural and biochemical studies reveal that human spermine synthase is an obligate dimer. Each monomer contains a C-terminal domain where the active site is located, a central linking domain that also forms the lid of the catalytic domain, and an N-terminal domain that is structurally very similar to S-adenosylmethionine decarboxylase. Gyro mice, which have an X-chromosomal deletion including the spermine synthase (SMS) gene, lack all spermine and have a greatly reduced size, sterility, deafness, neurological abnormalities, and a tendency to sudden death. Mutations in the human SMS lead to a rise in spermidine and reduction of spermine causing Snyder-Robinson syndrome, an X-linked recessive condition characterized by mental retardation, skeletal defects, hypotonia, and movement disorders.
| S-EPMC2822986 | biostudies-literature
Project description:Rapid synthesis of the polyamine catabolic enzyme spermidine/spermine-N(1)-acetyltransferase (SSAT) in response to increased polyamines is an important polyamine homeostatic mechanism. Indirect evidence has suggested that there is an important control mechanism involving the release of a translational repressor protein that allows the immediate initiation of SSAT protein synthesis without RNA transcription, maturation, or translocation. To identify a repressor protein, we used a mass spectroscopy-based RNA-protein interaction system and found six proteins that bind to the coding region of SSAT mRNA. Individual small interfering RNA (siRNA) experiments showed that nucleolin knockdown enhances SSAT translation. Nucleolin exists in several isoforms, and we report that the isoform that binds to SSAT mRNA undergoes autocatalysis in the presence of polyamines, a result suggesting that there is a negative feedback system that helps control the cellular content of polyamines. Preliminary molecular interaction data show that a nucleolin isoform binds to a 5' stem-loop of the coding region of SSAT mRNA. The glycine/arginine-rich C terminus of nucleolin is required for binding, and the four RNA recognition motif domains are included in the isoform that blocks SSAT translation. Understanding SSAT translational control mechanisms has the potential for the development of therapeutic strategies against cancer and obesity.
| S-EPMC3318587 | biostudies-literature
Project description:The polyamines, putrescine, spermidine, and spermine, are essential polycations, intimately involved in the regulation of cellular proliferation. Although polyamines exert dynamic effects on the conformation of nucleic acids and macromolecular synthesis in vitro, their specific functions in vivo are poorly understood. We investigated the cellular function of polyamines by overexpression of a key catabolic enzyme, spermidine/spermine N(1)-acetyltransferase 1 (SAT1) in mammalian cells. Transient cotransfection of HeLa cells with GFP and SAT1 vectors suppressed GFP protein expression without lowering its mRNA level, an indication that the block in GFP expression was not at transcription, but at translation. Fluorescence single-cell imaging also revealed specific inhibition of endogenous protein synthesis in the SAT1 overexpressing cells, without any inhibition of synthesis of DNA or RNA. Overexpression of SAT1 using a SAT1 adenovirus led to rapid depletion of cellular spermidine and spermine, total inhibition of protein synthesis, and growth arrest within 24 h. The SAT1 effect is most likely due to depletion of spermidine and spermine, because stable polyamine analogs that are not substrates for SAT1 restored GFP and endogenous protein synthesis. Loss of polysomes with increased 80S monosomes in the polyamine-depleted cells suggests a direct role for polyamines in translation initiation. Our data provide strong evidence for a primary function of polyamines, spermidine and spermine, in translation in mammalian cells.
| S-EPMC3568356 | biostudies-literature
Project description:Asthma is a heterologous disease that is influenced by complex interactions between multiple environmental exposures, metabolism, and host immunoregulatory processes. Specific metabolites are increasingly recognized to influence respiratory inflammation. However, the role of protein-derived metabolites in regulating inflammatory responses in the lung are poorly described. The aims of the present study were to quantify polyamine levels in bronchoalveolar lavages (BALs) from healthy volunteers and asthma patients, and to evaluate the impact of each polyamine on inflammatory responses using in vitro models and in a house dust mite (HDM)-induced respiratory allergy model. Spermidine levels were decreased, while cadaverine levels were increased in BALs from asthma patients compared to healthy controls, using Ultra Performance Liquid Chromatography (UPLC). Both spermine and spermidine inhibit lipopolysaccharide (LPS)-induced cytokine secretion from human peripheral blood mononuclear cells (PBMCs) and dendritic cells (DCs) in vitro. In addition, oral gavage with spermine or spermidine modulate HDM-induced cell infiltration, cytokine secretion, and epithelial cell tight junction expression in murine models. Spermidine also reduces airway hyper-responsiveness. These results suggest that modulation of polyamine metabolism, in particular spermidine, is associated with respiratory inflammation and these molecules and pathways should be further explored as biomarkers of disease and potential targets for novel therapies.
| S-EPMC8294051 | biostudies-literature
Project description:The N1-acetylation of spermidine and spermine by spermidine/spermine acetyltransferase (SSAT) is a crucial step in the regulation of the cellular polyamine levels in eukaryotic cells. Altered polyamine levels are associated with a variety of cancers as well as other diseases, and key enzymes in the polyamine pathway, including SSAT, are being explored as potential therapeutic drug targets. We have expressed and purified human SSAT in Escherichia coli and characterized its kinetic and chemical mechanism. Initial velocity and inhibition studies support a random sequential mechanism for the enzyme. The bisubstrate analogue, N1-spermine-acetyl-coenzyme A, exhibited linear, competitive inhibition against both substrates with a true Ki of 6 nM. The pH-activity profile was bell-shaped, depending on the ionization state of two groups exhibiting apparent pKa values of 7.27 and 8.87. The three-dimensional crystal structure of SSAT with bound bisubstrate inhibitor was determined at 2.3 A resolution. The structure of the SSAT-spermine-acetyl-coenzyme A complex suggested that Tyr140 acts as general acid and Glu92, through one or more water molecules, acts as the general base during catalysis. On the basis of kinetic properties, pH dependence, and structural information, we propose an acid/base-assisted reaction catalyzed by SSAT, involving a ternary complex.
| S-EPMC2518666 | biostudies-literature
Project description:Aging is the most important risk factor for cardiovascular disease (CVD). Slowing or reversing the physiological impact of heart aging may reduce morbidity and mortality associated with age-related CVD. The polyamines, spermine (SP) and spermidine (SPD) are essential for cell growth, differentiation and apoptosis, and levels of both decline with age. To explore the effects of these polyamines on heart aging, we administered SP or SPD intraperitoneally to 22- to 24-month-old rats for 6 weeks. Both treatments reversed and inhibited age-related myocardial morphology alterations, myocardial fibrosis, and cell apoptosis. Using combined proteomics and metabolomics analyses, we identified proteins and metabolites up- or downregulated by SP and SPD in aging rat hearts. SP upregulated 51 proteins and 28 metabolites while downregulating 80 proteins and 29 metabolites. SPD upregulated 44 proteins and 24 metabolites and downregulated 84 proteins and 176 metabolites. These molecules were mainly associated with immune responses, blood coagulation, lipid metabolism, and glutathione metabolism pathways. Our study provides novel molecular information on the cardioprotective effects of polyamines in the aging heart, and supports the notion that SP and SPD are potential clinical therapeutics targeting heart disease.
| S-EPMC5630292 | biostudies-literature
Project description:BACKGROUND:Tau stabilizes microtubules; however, in Alzheimer's disease (AD) and tauopathies, tau becomes hyperphosphorylated, aggregates, and results in neuronal death. Our group recently uncovered a unique interaction between polyamine metabolism and tau fate. Polyamines exert an array of physiological effects that support neuronal function and cognitive processing. Specific stimuli can elicit a polyamine stress response (PSR), resulting in altered central polyamine homeostasis. Evidence suggests that elevations in polyamines following a short-term stressor are beneficial; however, persistent stress and subsequent PSR activation may lead to maladaptive polyamine dysregulation, which is observed in AD, and may contribute to neuropathology and disease progression. METHODS:Male and female mice harboring tau P301L mutation (rTg4510) were examined for a tau-induced central polyamine stress response (tau-PSR). The direct effect of tau-PSR byproducts on tau fibrillization and oligomerization were measured using a thioflavin T assay and a N2a split superfolder GFP-Tau (N2a-ssGT) cell line, respectively. To therapeutically target the tau-PSR, we bilaterally injected caspase 3-cleaved tau truncated at aspartate 421 (AAV9 Tau ΔD421) into the hippocampus and cortex of spermidine/spermine-N1-acetyltransferase (SSAT), a key regulator of the tau-PSR, knock out (SSAT-/-), and wild type littermates, and the effects on tau neuropathology, polyamine dysregulation, and behavior were measured. Lastly, cellular models were employed to further examine how SSAT repression impacted tau biology. RESULTS:Tau induced a unique tau-PSR signature in rTg4510 mice, notably in the accumulation of acetylated spermidine. In vitro, higher-order polyamines prevented tau fibrillization but acetylated spermidine failed to mimic this effect and even promoted fibrillization and oligomerization. AAV9 Tau ΔD421 also elicited a unique tau-PSR in vivo, and targeted disruption of SSAT prevented the accumulation of acetylated polyamines and impacted several tau phospho-epitopes. Interestingly, SSAT knockout mice presented with altered behavior in the rotarod task, the elevated plus maze, and marble burying task, thus highlighting the impact of polyamine homeostasis within the brain. CONCLUSION:These data represent a novel paradigm linking tau pathology and polyamine dysfunction and that targeting specific arms within the polyamine pathway may serve as new targets to mitigate certain components of the tau phenotype.
| S-EPMC6599347 | biostudies-literature
Project description:OBJECTIVE:Cold and β3-adrenergic receptor (AR) agonists activate beige adipocyte biogenesis in white adipose tissue (WAT). The two stimuli also induce expression of inflammatory cytokines in WAT. The low-grade inflammation may further promote WAT browning. However, the mechanisms to reconcile these two biological processes remain to be elucidated. In this study, we aim to investigate the roles of the rate-limiting polyamine catabolic enzyme spermidine/spermine N1-acetyltransferase (SAT1) in regulating beige adipocyte biogenesis and inflammation. METHODS:Adipose-specific SAT1 knockout mice (SAT1-aKO) were generated by crossing adiponectin-cre to SAT1-lox/lox mice. Metabolic phenotype was investigated. Primary pre-adipocytes were isolated from inguinal WAT (iWAT) and differentiated to adipocytes for studying beige adipocyte biogenesis. RESULT:The expression and enzymatic activity of SAT1 were up-regulated in iWAT upon cold and β3-AR stimulation. SAT1-aKO mice developed late-onset obesity on a high-fat diet with impaired cold-induced beige adipocyte biogenesis and energy expenditure. RNA-seq analysis of iWAT from cold-challenged SAT1-aKO mice revealed that, in addition to beige adipocyte biogenesis signatures, the immune response markers were highly enriched among reduced genes. In cultured adipocytes, SAT1 overexpression or pharmacological activation with N1, N11-diethylnorspermine (DENSpm) elevated oxygen consumption and increased the expression of beige adipocyte marker UCP1 and PGC-1α. DENSpm treatment of adipocytes also increased the expression of inflammatory genes. SAT1 activation enhanced hydrogen peroxide production in adipocytes. Antioxidant N-acetylcysteine abrogated the elevated UCP1 expression and reversed some inflammatory genes induced by SAT1 activation. CONCLUSIONS:SAT1 activation plays a key role in cold and β3-AR agonist-induced beige adipocyte biogenesis and low-grade inflammation.
| S-EPMC7269456 | biostudies-literature