We have developed a one-step method to synthesize carbon quantum dots (CQDPAs) from biogenic polyamines (PAs) as an antibacterial agent for topical treatment of bacterial keratitis (BK). CQDs ...synthesized by direct pyrolysis of spermidine (Spd) powder through a simple dry heating treatment exhibit a solubility and yield much higher than those from putrescine and spermine. We demonstrate that CQDs obtained from Spds (CQDSpds) possess effective antibacterial activities against non-multidrug-resistant Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella enterica serovar Enteritidis bacteria and also against the multidrug-resistant bacteria, methicillin-resistant S. aureus. The minimal inhibitory concentration (MIC) of CQDSpds is ∼2500-fold lower than that of spermidine alone, demonstrating their strong antibacterial capabilities. Investigation of the possible mechanisms behind the antibacterial activities of the as-synthesized CQDSpds indicates that the super-cationic CQDSpds with small size (diameter ca. 6 nm) and highly positive charge (ζ-potential ca. +45 mV) cause severe disruption of the bacterial membrane. In vitro cytotoxicity, hemolysis, hemagglutination, genotoxicity, and oxidative stress and in vivo morphologic and physiologic cornea change evaluations show the good biocompatibility of CQDSpds. Furthermore, topical ocular administration of CQDSpds can induce the opening of the tight junction of corneal epithelial cells, thereby leading to great antibacterial treatment of S. aureus-induced BK in rabbits. Our results suggest that CQDSpds are a promising antibacterial candidate for clinical applications in treating eye-related bacterial infections and even persistent bacteria-induced infections.
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IJS, KILJ, NUK, PNG, UL, UM
Spermidine possesses multiple healthy functions, and soybeans contain the most abundant spermidine. In this study, spermidine contents of soybeans from different varieties and production regions in ...China were evaluated, and a spermidine synthase gene (speE) was identified by recombinant expression, transcriptional verification, and sequence analysis. Spermidine contents of soybean samples from 18 varieties ranged 72.38–228.82 mg/kg, and those from 19 production regions ranged 134.64–242.32 mg/kg. The highest-spermidine sample GZ was used to clone four predicted speE genes. Expressing the gene speE5 improved the spermidine titer by 54% in Bacillus amyloliquefaciens, confirming that speE5 was involved in spermidine synthesis. Transcriptional verification was performed through a soybean germination model. Germination for 48 h led to a onefold increase of spermidine in samples SHX and HB, and corresponding speE5 transcriptional levels were improved by 26-fold and 18-fold, respectively, further verifying the function of speE5. Finally, the sequences of the speE5 gene and deduced amino acids were analyzed, and the conserved sites and catalysis mechanisms were presented. This study identified an active spermidine synthase gene from soybean for the first time, which provided an important gene resource for genetic breeding of spermidine-rich soybean or microbial cell factory.
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Spermidine is a polyamine molecule that performs various cellular functions, such as DNA and RNA stabilization, autophagy modulation, and eIF5A formation, and is generated from putrescine by ...aminopropyltransferase spermidine synthase (SpdS). During synthesis, the aminopropyl moiety is donated from decarboxylated S-adenosylmethionine to form putrescine, with 5'-deoxy-5'-methylthioadenosine being produced as a byproduct. Although the molecular mechanism of SpdS function has been well-established, its structure-based evolutionary relationships remain to be fully understood. Moreover, only a few structural studies have been conducted on SpdS from fungal species. Here, we determined the crystal structure of an apo-form of SpdS from
(
SpdS) at 1.9 Å resolution. Structural comparison with its homologs revealed a conformational change in the α6 helix linked to the gate-keeping loop, with approximately 40° outward rotation. This change caused the catalytic residue Asp170 to move outward, possibly due to the absence of a ligand in the active site. These findings improve our understanding of the structural diversity of SpdS and provide a missing link that expands our knowledge of the structural features of SpdS in fungal species.
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4.
Spermidine in health and disease Madeo, Frank; Eisenberg, Tobias; Pietrocola, Federico ...
Science (American Association for the Advancement of Science),
01/2018, Volume:
359, Issue:
6374
Journal Article
Peer reviewed
Open access
Interventions that delay aging and protect from age-associated disease are slowly approaching clinical implementation. Such interventions include caloric restriction mimetics, which are defined as ...agents that mimic the beneficial effects of dietary restriction while limiting its detrimental effects. One such agent, the natural polyamine spermidine, has prominent cardioprotective and neuroprotective effects and stimulates anticancer immunosurveillance in rodent models. Moreover, dietary polyamine uptake correlates with reduced cardiovascular and cancer-related mortality in human epidemiological studies. Spermidine preserves mitochondrial function, exhibits anti-inflammatory properties, and prevents stem cell senescence. Mechanistically, it shares the molecular pathways engaged by other caloric restriction mimetics: It induces protein deacetylation and depends on functional autophagy. Because spermidine is already present in daily human nutrition, clinical trials aiming at increasing the uptake of this polyamine appear feasible.
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BFBNIB, NMLJ, NUK, ODKLJ, PNG, SAZU, UL, UM, UPUK
Because inflammatory bowel disease is increasing worldwide and can lead to colitis-associated carcinoma (CAC), new interventions are needed. We have shown that spermine oxidase (SMOX), which ...generates spermidine (Spd), regulates colitis. Here we determined whether Spd treatment reduces colitis and carcinogenesis. METHODS: SMOX was quantified in human colitis and associated dysplasia using quantitative reverse-transcription polymerase chain reaction and immunohistochemistry. We used wild-type (WT) and Smox−/− C57BL/6 mice treated with dextran sulfate sodium (DSS) or azoxymethane (AOM)-DSS as models of colitis and CAC, respectively. Mice with epithelial-specific deletion of Apc were used as a model of sporadic colon cancer. Animals were supplemented or not with Spd in the drinking water. Colonic polyamines, inflammation, tumorigenesis, transcriptomes, and microbiomes were assessed.
SMOX messenger RNA levels were decreased in human ulcerative colitis tissues and inversely correlated with disease activity, and SMOX protein was reduced in colitis-associated dysplasia. DSS colitis and AOM-DSS–induced dysplasia and tumorigenesis were worsened in Smox−/− vs WT mice and improved in both genotypes with Spd. Tumor development caused by Apc deletion was also reduced by Spd. Smox deletion and AOM-DSS treatment were both strongly associated with increased expression of α-defensins, which was reduced by Spd. A shift in the microbiome, with reduced abundance of Prevotella and increased Proteobacteria and Deferribacteres, occurred in Smox−/− mice and was reversed with Spd.
Loss of SMOX is associated with exacerbated colitis and CAC, increased α-defensin expression, and dysbiosis of the microbiome. Spd supplementation reverses these phenotypes, indicating that it has potential as an adjunctive treatment for colitis and chemopreventive for colon carcinogenesis.
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Expression of spermine oxidase, which synthesizes spermidine, is reduced in patients with colitis and dysplasia. Colitis and colitis-associated carcinogenesis are worsened by Smox deletion. Spermidine supplementation reduces colon inflammation and tumor development.
Phenolamines and flavonoids are two important components in bee pollen. There are many reports on the bioactivity of flavonoids in bee pollen, but few on phenolamines. This study aims to separate and ...characterize the flavonoids and phenolamines from rape bee pollen, and compare their antioxidant activities and protective effects against oxidative stress. The rape bee pollen was separated to obtain 35% and 50% fractions, which were characterized by HPLC-ESI-QTOF-MS/MS. The results showed that the compounds in 35% fraction were quercetin and kaempferol glycosides, while the compounds in 50% fraction were phenolamines, including di-p-coumaroyl spermidine, p-coumaroyl caffeoyl hydroxyferuloyl spermine, di-p-coumaroyl hydroxyferuloyl spermine, and tri-p-coumaroyl spermidine. The antioxidant activities of phenolamines and flavonoids were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), and ferric reducing antioxidant power (FRAP) assays. It was found that the antioxidant activity of phenolamines was significantly higher than that of flavonoids. Moreover, phenolamines showed better protective effects than flavonoids on HepG2 cells injured by AAPH. Furthermore, phenolamines could significantly reduce the reactive oxygen species (ROS), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and increase the superoxide dismutase (SOD) and glutathione (GSH) levels. This study lays a foundation for the further understanding of phenolamines in rape bee pollen.
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Hypericin, a natural compound from Hypericum perforatum (St. John's wort), has been identified as a specific inhibitor of Leishmania donovani spermidine synthase (LdSS) using integrated computational ...and biochemical approaches. Hypericin showed in vitro inhibition of recombinant LdSS enzyme activity. The in vivo estimation of spermidine levels in Leishmania promastigotes after hypericin treatment showed significant decreases in the spermidine pools of the parasites, indicating target specificity of the inhibitor molecule. The inhibitor, hypericin, showed significant antileishmanial activity, and the mode of death showed necrosis-like features. Further, decreased trypanothione levels and increased glutathione levels with elevated reactive oxygen species (ROS) levels were observed after hypericin treatment. Supplementation with trypanothione in the medium with hypericin treatment restored in vivo trypanothione levels and ROS levels but could not prevent necrosis-like death of the parasites. However, supplementation with spermidine in the medium with hypericin treatment restored in vivo spermidine levels and parasite death was prevented to a large extent. The data overall suggest that the parasite death due to spermidine starvation as a result of LdSS inhibition is not related to elevated levels of reactive oxygen species. This suggests the involvement of spermidine in processes other than redox metabolism in Leishmania parasites. Moreover, the work provides a novel scaffold, i.e., hypericin, as a potent antileishmanial molecule.
Supplementation of spermidine, an autophagy-inducing agent, has been shown to protect against neurodegeneration and cognitive decline in aged animal models. The present translational study aimed to ...determine safety and tolerability of a wheat germ extract containing enhanced spermidine concentrations. In a preclinical toxicity study, supplementation of spermidine using this extract did not result in morbidities or changes in behavior in BALBc/Rj mice during the 28-days repeated-dose tolerance study. Post mortem examination of the mice organs showed no increase in tumorigenic and fibrotic events. In the human cohort (participants with subjective cognitive decline, n=30, 60 to 80 years of age), a 3-month randomized, placebo-controlled, double-blind Phase II trial was conducted with supplementation of the spermidine-rich plant extract (dosage: 1.2 mg/day). No differences were observed between spermidine and placebo-treated groups in vital signs, weight, clinical chemistry and hematological parameters of safety, as well as in self-reported health status at the end of intervention. Compliance rates above 85% indicated excellent tolerability. The data demonstrate that spermidine supplementation using a spermidine-rich plant extract is safe and well-tolerated in mice and older adults. These findings allow for longer-term intervention studies in humans to investigate the impact of spermidine treatment on cognition and brain integrity.
The availability of fully sequenced bacterial genomes has revealed that many species known to synthesize the polyamine spermidine lack the spermidine biosynthetic enzymes S-adenosylmethionine ...decarboxylase and spermidine synthase. We found that such species possess orthologues of the sym-norspermidine biosynthetic enzymes carboxynorspermidine dehydrogenase and carboxynorspermidine decarboxylase. By deleting these genes in the food-borne pathogen Campylobacter jejuni, we found that the carboxynorspermidine decarboxylase orthologue is responsible for synthesizing spermidine and not sym-norspermidine in vivo. In polyamine auxotrophic gene deletion strains of C. jejuni, growth is highly compromised but can be restored by exogenous sym-homospermidine and to a lesser extent by sym-norspermidine. The alternative spermidine biosynthetic pathway is present in many bacterial phyla and is the dominant spermidine route in the human gut, stomach, and oral microbiomes, and it appears to have supplanted the S-adenosylmethionine decarboxylase/spermidine synthase pathway in the gut microbiota. Approximately half of the gut Firmicutes species appear to be polyamine auxotrophs, but all encode the potABCD spermidine/putrescine transporter. Orthologues encoding carboxyspermidine dehydrogenase and carboxyspermidine decarboxylase are found clustered with an array of diverse putrescine biosynthetic genes in different bacterial genomes, consistent with a role in spermidine, rather than sym-norspermidine biosynthesis. Due to the pervasiveness of ϵ-proteobacteria in deep sea hydrothermal vents and to the ubiquity of the alternative spermidine biosynthetic pathway in that phylum, the carboxyspermidine route is also dominant in deep sea hydrothermal vents. The carboxyspermidine pathway for polyamine biosynthesis is found in diverse human pathogens, and this alternative spermidine biosynthetic route presents an attractive target for developing novel antimicrobial compounds.
Background: Many bacteria synthesize spermidine but lack orthologues of polyamine biosynthetic enzymes S-adenosylmethionine decarboxylase and spermidine synthase.
Results: An alternative spermidine biosynthetic pathway is essential in Campylobacter jejuni.
Conclusion: The alternative route via carboxyspermidine is the dominant pathway in the human gut microbiota and deep sea hydrothermal vents.
Significance: A multiplicity of polyamine biosynthetic pathways exist, providing novel targets for development of antimicrobial drugs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Polyamines play pivotal roles in plant defense to environmental stresses. However, stress tolerance of genetically engineered plants for polyamine biosynthesis has been little examined so far. We ...cloned spermidine synthase cDNA from Cucurbita ficifolia and the gene was introduced to Arabidopsis thaliana under the control of the cauliflower mosaic virus 35S promoter. The transgene was stably integrated and actively transcribed in the transgenic plants. As compared with the wild-type plants, the T2 and T3 transgenic plants exhibited a significant increase in spermidine synthase activity and spermidine content in leaves together with enhanced tolerance to various stresses including chilling, freezing, salinity, hyperosmosis, drought, and paraquat toxicity. During exposure to chilling stress (5 deg C), the transgenics displayed a remarkable increase in arginine decarboxylase activity and conjugated spermidine contents in leaves compared to the wild type. A cDNA microarray analysis revealed that several genes were more abundantly transcribed in the transgenics than in the wild type under chilling stress. These genes included those for stress-responsive transcription factors such as DREB and stress-protective proteins like rd29A. These results strongly suggest an important role for spermidine as a signaling regulator in stress signaling pathways, leading to build-up of stress tolerance mechanisms in plants under stress conditions.
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