Polyamines on the reproductive landscape

Physiological importance of polyamines

Polyamines are polycationic molecules that contain two or more amino groups (-NH3 +) and are present in all eukaryotic and prokaryotic cells. Polyamines are synthesized from arginine, ornithine, and proline, and from methionine as the methyl-group donor. In the traditional pathway for polyamine synthesis, arginase converts arginine into ornithine, which is decarboxylated by ornithine decarboxylase (ODC1) to generate putrescine. The latter is converted to spermidine and spermine. Recent studies have indicated the existence of 'non-classical pathways' for the generation of putrescine from arginine and proline in animal cells. Specifically, arginine decarboxylase (ADC) catalyzes the conversion of arginine into agmatine, which is hydrolyzed by agmatinase (AGMAT) to form putrescine. Additionally, proline is oxidized by proline oxidase to yield pyrroline-5-carboxylate, which undergoes transamination with glutamate to produce ornithine for decarboxylation by ODC1. Intracellular production of polyamines is controlled by antizymes binding to and inactivating ODC1. Polyamines exert effects that include stimulation of cell division and proliferation, gene expression for the survival of cells, DNA and protein synthesis, regulation of apoptosis, oxidative stress, angiogenesis, and cell-cell communication activity. Accordingly, polyamines are essential for early embryonic development and successful pregnancy outcome in mammals. In this paper the main concepts on the history, structure and molecular pathways of polyamines as well as their physiological role on angiogenesis, and reproductive physiology are reviewed.

Neuromodulation of Innate Behaviors in Drosophila

Animals are born with a rich repertoire of robust behaviors that are critical for their survival. However, innate behaviors are also highly adaptable to an animal's internal state and external environment. Neuromodulators, including biogenic amines, neuropeptides, and hormones, are released to signal changes in animals' circumstances and serve to reconfigure neural circuits. This circuit flexibility allows animals to modify their behavioral responses according to environmental cues, metabolic demands, and physiological states. Aided by powerful genetic tools, researchers have made remarkable progress in Drosophila melanogaster to address how a myriad of contextual information influences the input-output relationship of hardwired circuits that support a complex behavioral repertoire. Here we highlight recent advances in understanding neuromodulation of Drosophila innate behaviors, with a special focus on feeding, courtship, aggression, and postmating behaviors.

OAZ1 knockdown enhances viability and inhibits ER and LHR transcriptions of granulosa cells in geese

An increasing number of studies suggest that ornithine decarboxylase antizyme 1 (OAZ1), which is regarded as a tumor suppressor gene, regulates follicular development, ovulation, and steroidogenesis. The granulosa cells in the ovary play a critical role in these ovarian functions. However, the action of OAZ1 mediating physiological functions of granulosa cells is obscure. OAZ1 knockdown in granulosa cells of geese was carried out in the current study. The effect of OAZ1 knockdown on polyamine metabolism, cell proliferation, apoptosis, and hormone receptor transcription of primary granulosa cells in geese was measured. The viability of granulosa cells transfected with the shRNA OAZ1 at 48 h was significantly higher than the control (p<0.05). The level of putrescine and spermidine in granulosa cells down-regulating OAZ1 was 7.04- and 2.11- fold higher compared with the control, respectively (p<0.05). The CCND1, SMAD1, and BCL-2 mRNA expression levels in granulosa cells down-regulating OAZ1 were each significantly higher than the control, respectively (p<0.05), whereas the PCNA and CASPASE 3 expression levels were significantly lower than the control (p<0.05). The estradiol concentration, ER and LHR mRNA expression levels were significantly lower in granulosa cells down-regulating OAZ1 compared with the control (p<0.05). Taken together, our results indicated that OAZ1 knockdown elevated the putrescine and spermidine contents and enhanced granulosa cell viability and inhibited ER and LHR transcriptions of granulosa cells in geese.

TEX13 is a novel male germ cell-specific nuclear protein potentially involved in transcriptional repression

The identification and characterization of male germ cell-specific genes is crucial to understanding the mechanisms of male germ cell development. In this study, we investigated the protein encoded by the novel mouse germ cell-specific gene testis-expressed gene 13 (Tex13). We found that TEX13 expression is testis- and germ cell-specific and is regulated in a stage-specific manner via translational repression. Immunostaining of testicular cells and sperm showed that TEX13 is localized in the nuclei of spermatogenic cells and the redundant nuclear envelope of mature sperm. Remarkably, we found that TEX13 possesses transcriptional repressor activity and that its overexpression in GC-2 cells altered the expression levels of 130 genes. Our results suggest that TEX13 has a potential role in transcriptional regulation during spermatogenesis.

Functions of Polyamines in Mammals

The content of spermidine and spermine in mammalian cells has important roles in protein and nucleic acid synthesis and structure, protection from oxidative damage, activity of ion channels, cell proliferation, differentiation, and apoptosis. Spermidine is essential for viability and acts as the precursor of hypusine, a post-translational addition to eIF5A allowing the translation of mRNAs encoding proteins containing polyproline tracts. Studies with Gy mice and human patients with the very rare X-linked genetic condition Snyder-Robinson syndrome that both lack spermine synthase show clearly that the correct spermine:spermidine ratio is critical for normal growth and development.

Ionotropic Chemosensory Receptors Mediate the Taste and Smell of Polyamines

The ability to find and consume nutrient-rich diets for successful reproduction and survival is fundamental to animal life. Among the nutrients important for all animals are polyamines, a class of pungent smelling compounds required in numerous cellular and organismic processes. Polyamine deficiency or excess has detrimental effects on health, cognitive function, reproduction, and lifespan. Here, we show that a diet high in polyamine is beneficial and increases reproductive success of flies, and we unravel the sensory mechanisms that attract Drosophila to polyamine-rich food and egg-laying substrates. Using a combination of behavioral genetics and in vivo calcium imaging, we demonstrate that Drosophila uses multisensory detection to find and evaluate polyamines present in overripe and fermenting fruit, their favored feeding and egg-laying substrate. In the olfactory system, two coexpressed ionotropic receptors (IRs), IR76b and IR41a, mediate the long-range attraction to the odor. In the gustatory system, multimodal taste sensation by IR76b receptor and GR66a bitter receptor neurons is used to evaluate quality and valence of the polyamine providing a mechanism for the fly’s high attraction to polyamine-rich and sweet decaying fruit. Given their universal and highly conserved biological roles, we propose that the ability to evaluate food for polyamine content may impact health and reproductive success also of other animals including humans.

Polyamines are beneficial nutrients for reproduction, cognition, and lifespan. This study reveals that insects are highly attracted to them and identify their sources through an ancient class of ionotropic receptors on their smell and taste organs.

Animals, including humans, evaluate food by its smell and taste. Odors and tastes not only signal the presence of food, they also reveal details about the type and amount of nutrients contained in it. A preference for certain foods frequently reflects the specific metabolic needs of an animal. Among the important but less known compounds that animals consume with their diet are polyamines. These pungent smelling molecules are essential for reproduction, development, and cognition. Interestingly, they are also produced by the cell and body, but their levels decline with age. A diet high in polyamines can improve age-related memory deficits and loss of fertility. We have used the model fly Drosophila melanogaster to unravel if and how animals detect polyamines in their food and environment, and which role this detection plays in their food choice behavior. Polyamine levels are particularly high in the fly’s favorite food and egg-laying substrate, overripe and decaying fruit. We found that food supplemented with polyamines indeed improves the reproductive success of a fly couple. We show that Drosophila is highly attracted to polyamines and uses them to identify promising egg-laying and feeding sites. It detects them through an ancient clade of receptor proteins on its olfactory and taste organs. We speculate that other animals can also detect polyamines and use their smell and taste to identify sources of these beneficial nutrients.

Neuropeptides Modulate Female Chemosensory Processing upon Mating in Drosophila

A female's reproductive state influences her perception of odors and tastes along with her changed behavioral state and physiological needs. The mechanism that modulates chemosensory processing, however, remains largely elusive. Using Drosophila, we have identified a behavioral, neuronal, and genetic mechanism that adapts the senses of smell and taste, the major modalities for food quality perception, to the physiological needs of a gravid female. Pungent smelling polyamines, such as putrescine and spermidine, are essential for cell proliferation, reproduction, and embryonic development in all animals. A polyamine-rich diet increases reproductive success in many species, including flies. Using a combination of behavioral analysis and in vivo physiology, we show that polyamine attraction is modulated in gravid females through a G-protein coupled receptor, the sex peptide receptor (SPR), and its neuropeptide ligands, MIPs (myoinhibitory peptides), which act directly in the polyamine-detecting olfactory and taste neurons. This modulation is triggered by an increase of SPR expression in chemosensory neurons, which is sufficient to convert virgin to mated female olfactory choice behavior. Together, our data show that neuropeptide-mediated modulation of peripheral chemosensory neurons increases a gravid female's preference for important nutrients, thereby ensuring optimal conditions for her growing progeny.

Arginine- and Polyamine-Induced Lactic Acid Resistance in Neisseria gonorrhoeae

Microbe-derived lactic acid protects women from pathogens in their genital tract. The purpose of this study was to determine lactic acid susceptibility of Neisseria gonorrhoeae, and identify potential acid resistance mechanisms present in this pathogen. Tested in vitro, lactic acid killed all 10 gonococcal strains analyzed in a low pH-dependent manner. Full inactivation occurred at pH 4.5. At low pH, lactic acid treatment resulted in the entry of the DNA-binding fluorochrome propidium iodide into the microbial cells, suggesting that hydrogen ions from lactic acid compromise the integrity of the bacterial cell wall/membrane. Most likely, hydrogen ions also inactivate intracellular proteins since arginine rendered significant protection against lactic acid presumably through action of the gonococcal arginine decarboxylase, an enzyme located in the bacterial cytoplasm. Surprisingly, arginine also lessened lactic acid-mediated cell wall/membrane disruption. This effect is probably mediated by agmatine, a triamine product of arginine decarboxylase, since agmatine demonstrated a stronger protective effect on GC than arginine at equal molar concentration. In addition to agmatine, diamines cadaverine and putrescine, which are generated by bacterial vaginosis-associated microbes, also induced significant resistance to lactic acid-mediated GC killing and cell wall/membrane disruption. These findings suggest that the arginine-rich semen protects gonococci through both neutralization-dependent and independent mechanisms, whereas polyamine-induced acid resistance contributes to the increased risk of gonorrhea in women with bacterial vaginosis.

Targeting oocyte maturation to improve fertility in older women

Reproductive aging is an increasingly pressing problem facing women in modern society, due to delay in child bearing. According to Statistics Canada, 52% of all Canadian births in 2011 were by women aged 30 years and older, up from 24% in 1981 ( http://www.statcan.gc.ca/pub/91-209-x/2013001/article/11784-eng.htm ). Women older than 35 years of age experience significantly increased risks of infertility, miscarriage and congenital birth defects, mostly due to poor quality of the eggs. Increasingly sophisticated, and often invasive, assisted reproductive technologies (ARTs) have helped millions of women to achieve reproductive success. However, by and large, ARTs do not address the fundamental issue of reproductive aging in women: age-related decline in egg quality. More importantly, ARTs are not, and will never be, the main solution for the general population. Here, I attempt to review the scientific literature on age-related egg quality decline, based mostly on studies in mice and in humans. Emphasis is given to the brief period of time called oocyte maturation, which occurs just prior to ovulation. The rationale for this emphasis is that oocyte maturation represents a critical window where unfavorable ovarian conditions in older females contribute significantly to the decline of egg quality, and that science-based intervention during oocyte maturation represents the best chance of improving egg quality in older women. Finally, I summarize our own work in recent years on peri-ovulatory putrescine supplementation as a possible remedy for reproductive aging.

Progesterone secretion by ovine granulosa cells: effects of nitric oxide and plane of nutrition

The aim was to evaluate the effects of nutritional plane on in vitro progesterone (P4) secretion by granulosa (G) cells cultured in the presence or absence of effectors of the nitric oxide (NO) system. Ewes were randomly assigned into three nutritional groups: control (C), overfed (O; 2 × C), or underfed (U; 0.6 × C). Follicular development was induced by FSH injections. On day 15 of the estrous cycle, G cells were isolated and cultured with or without DETA-NONOate (NO donor), L-NAME (NO synthase [S] inhibitor), Arg and (or) LH for 8 h. DETA-NONOate decreased basal and LH-stimulated P4 secretion, and L-NAME increased basal P4 secretion in all groups. In U, Arg decreased LH-stimulated P4 secretion. These data demonstrate that (i) plane of nutrition affects basal P4 secretion by G cells, (ii) the NO donor decreases, NOS inhibitor increases but Arg does not affect basal P4 secretion, and (iii) effects of Arg on LH-stimulated P4 secretion are affected by plane of nutrition in FSH-treated sheep. Thus, plane of nutrition affects G cell function, and the NO system is involved in the regulation of basal and LH-stimulated P4 secretion. The mechanism of the NO system effects on secretory activity of G cells remains to be elucidated.

Molecular cloning and mRNA expression analysis of antizyme inhibitor 1 in the ovarian follicles of the Sichuan white goose

Antizyme inhibitor 1 (Azin1) plays critical roles in various cellular pathways, including ornithine decarboxylase regulation, polyamine anabolism and uptake and cell proliferation. However, the molecular characteristics of the AZIN1 gene and its expression profile in goose tissues and ovarian follicles have not been reported. In this study, the AZIN1 cDNA of the Sichuan white goose (Anser cygnoides) was cloned, and analyzed for its phylogenetic and physiochemical properties. The expression profile of AZIN1 mRNA in geese tissues and ovarian follicles were examined using quantitative real-time PCR. The results showed that the open reading frame of the AZIN1 cDNA is 1,353 bp in length, encoding a 450 amino acid protein with a molecular weight of 50 kDa. Out of all tissues examined, AZIN1 expression was highest in the adrenal gland and lowest in breast muscle. There was also a high expression of AZIN1 in the cerebellum and isthmus of oviduct. With follicular development, AZIN1 gene expression gradually increased, and its expression in F1 was significantly higher than in F5 (P<0.05). AZIN1 expression was also significantly higher in the POF1 than in the other follicles (P<0.05), and there was a low mRNA expression of AZIN1 in atretic follicles. The results of AZIN1 expression profiling in ovarian follicles suggest that AZIN1 may play an important role in the progression of follicular development, potentially through regulating polyamine levels.

Sexual transfer of the steroid hormone 20E induces the postmating switch in Anopheles gambiae

Female insects generally mate multiple times during their lives. A notable exception is the female malaria mosquito Anopheles gambiae, which after sex loses her susceptibility to further copulation. Sex in this species also renders females competent to lay eggs developed after blood feeding. Despite intense research efforts, the identity of the molecular triggers that cause the postmating switch in females, inducing a permanent refractoriness to further mating and triggering egg-laying, remains elusive. Here we show that the male-transferred steroid hormone 20-hydroxyecdysone (20E) is a key regulator of monandry and oviposition in An. gambiae. When sexual transfer of 20E is impaired by partial inactivation of the hormone and inhibition of its biosynthesis in males, oviposition and refractoriness to further mating in the female are strongly reduced. Conversely, mimicking sexual delivery by injecting 20E into virgin females switches them to an artificial mated status, triggering egg-laying and reducing susceptibility to copulation. Sexual transfer of 20E appears to incapacitate females physically from receiving seminal fluids by a second male. Comparative analysis of microarray data from females after mating and after 20E treatment indicates that 20E-regulated molecular pathways likely are implicated in the postmating switch, including cytoskeleton and musculature-associated genes that may render the atrium impenetrable to additional mates. By revealing signals and pathways shaping key processes in the An. gambiae reproductive biology, our data offer new opportunities for the control of natural populations of malaria vectors.

Natural polyamines inhibit the migration of preosteoclasts by attenuating Ca2+-PYK2-Src-NFATc1 signaling pathways

Natural polyamines have numerous biological activities. Several studies have reported their beneficial role in bone metabolism, but their mode of action is not fully understood. Bone diseases such as osteoporosis, which is characterized by impaired bone structure and low bone mass, are caused by an increased number of osteoclasts and/or overactivation of osteoclastogenesis. Osteoclast differentiation is a multi-complex procedure involving the following sequential steps: differentiation-migration-fusion-resorption. In this study, we found that putrescine, spermidine or spermine inhibited the RANKL-mediated migration of preosteoclasts. Furthermore, the RANKL-mediated activation of the Src-PYK2 signaling axis and of transcription factors such as NF-κB and NFATc1 was prevented by each polyamine. Anti-osteoclastogenic and anti-migration activities of polyamines were confirmed by evaluating their potential to downregulate the mRNA expression levels of osteoclastogenesis-related genes such as OSCAR, TRAP, cathepsin K and c-Src, and genes related to fusion and/or migration of preosteoclasts. Moreover, ATP-mediated elevation of cytosolic free Ca(2+) concentration ([Ca(2+)]i) was strongly inhibited by each polyamine, indicating the involvement of [Ca(2+)]i in the anti-fusion activities of polyamines. In conclusion, polyamines could exhibit anti-osteoclastogenic activity by inhibiting the migration of preosteoclasts via the Ca(2+)-PYK2-Src-NFATc1 signaling axis.

Does dietary folic acid supplementation in mouse NTD models affect neural tube development or gamete preference at fertilization?

Background

Neural tube defects (NTDs) are the second most common birth defect in humans. Dietary folic acid (FA) supplementation effectively and safely reduces the incidence of these often debilitating congenital anomalies. FA plays an established role in folate and homocysteine metabolism, but the means by which it suppresses occurrence of NTDs is not understood. In addition, many cases remain resistant to the beneficial effects of folic acid supplementation. To better understand the molecular, biochemical and developmental mechanisms by which FA exerts its effect on NTDs, characterized mouse models are needed that have a defined genetic basis and known response to dietary supplementation.

Results

We examined the effect of FA supplementation, at 5-fold the level in the control diet, on the NTD and vertebral phenotypes in Apob^tm1Unc and Vangl2^Lp mice, hereafter referred to as Apob and Lp respectively. The FA supplemented diet did not reduce the incidence or severity of NTDs in Apob or Lp mutant homozygotes or the loop-tail phenotype in Lp mutant heterozygotes, suggesting that mice with these mutant alleles are resistant to FA supplementation. Folic acid supplementation also did not affect the rate of resorptions or the size of litters, but instead skewed the embryonic genotype distribution in favor of wild-type alleles.

Conclusion

Similar genotypic biases have been reported for several NTD models, but were interpreted as diet-induced increases in the incidence and severity of NTDs that led to increased embryonic lethality. Absence of differences in resorption rates and litter sizes argue against induced embryonic lethality. We suggest an alternative interpretation, namely that FA supplementation led to strongly skewed allelic inheritance, perhaps from disturbances in polyamine metabolism that biases fertilization in favor of wild-type gametes.

Fertility and polarized cell growth depends on eIF5A for translation of polyproline-rich formins in Saccharomyces cerevisiae

eIF5A is an essential and evolutionary conserved translation elongation factor, which has recently been proposed to be required for the translation of proteins with consecutive prolines. The binding of eIF5A to ribosomes occurs upon its activation by hypusination, a modification that requires spermidine, an essential factor for mammalian fertility that also promotes yeast mating. We show that in response to pheromone, hypusinated eIF5A is required for shmoo formation, localization of polarisome components, induction of cell fusion proteins, and actin assembly in yeast. We also show that eIF5A is required for the translation of Bni1, a proline-rich formin involved in polarized growth during shmoo formation. Our data indicate that translation of the polyproline motifs in Bni1 is eIF5A dependent and this translation dependency is lost upon deletion of the polyprolines. Moreover, an exogenous increase in Bni1 protein levels partially restores the defect in shmoo formation seen in eIF5A mutants. Overall, our results identify eIF5A as a novel and essential regulator of yeast mating through formin translation. Since eIF5A and polyproline formins are conserved across species, our results also suggest that eIF5A-dependent translation of formins could regulate polarized growth in such processes as fertility and cancer in higher eukaryotes.

Amine oxidase copper-containing 1 (AOC1) is a downstream target gene of the Wilms tumor protein, WT1, during kidney development

Amine oxidase copper-containing 1 (AOC1; formerly known as amiloride-binding protein 1) is a secreted glycoprotein that catalyzes the degradation of putrescine and histamine. Polyamines and their diamine precursor putrescine are ubiquitous to all organisms and fulfill pivotal functions in cell growth and proliferation. Despite the importance of AOC1 in regulating polyamine breakdown, very little is known about the molecular mechanisms that control its expression. We report here that the Wilms tumor protein, WT1, which is necessary for normal kidney development, activates transcription of the AOC1 gene. Expression of a firefly luciferase reporter under control of the proximal AOC1 promoter was significantly enhanced by co-transfection of a WT1 expression construct. Binding of WT1 protein to a cis-regulatory element in the AOC1 promoter was confirmed by electrophoretic mobility shift assay and chromatin immunoprecipitation. Antisense inhibition of WT1 protein translation strongly reduced Aoc1 transcripts in cultured murine embryonic kidneys and gonads. Aoc1 mRNA levels correlated with WT1 protein in several cell lines. Double immunofluorescent staining revealed a co-expression of WT1 and AOC1 proteins in the developing genitourinary system of mice and rats. Strikingly, induced changes in polyamine homeostasis affected branching morphogenesis of cultured murine embryonic kidneys in a developmental stage-specific manner. These findings suggest that WT1-dependent control of polyamine breakdown, which is mediated by changes in AOC1 expression, has a role in kidney organogenesis.

Arginine decarboxylase and agmatinase: an alternative pathway for de novo biosynthesis of polyamines for development of mammalian conceptuses

Ornithine decarboxylase (ODC1) is considered the rate-controlling enzyme for the classical de novo biosynthesis of polyamines (putrescine, spermidine, and spermine) in mammals. However, metabolism of arginine to agmatine via arginine decarboxylase (ADC) and conversion of agmatine to polyamines via agmatinase (AGMAT) is an alternative pathway long recognized in lower organisms, but only recently suggested for neurons and liver cells of mammals. We now provide evidence for a functional ADC/AGMAT pathway for the synthesis of polyamines in mammalian reproductive tissue for embryonic survival and development. We first investigated cellular functions of polyamines by in vivo knockdown of translation of mRNA for ODC1 in ovine conceptus trophectoderm using morpholino antisense oligonucleotides (MAOs) and found that one-half of the conceptuses were morphologically and functionally either normal or abnormal. Furthermore, we found that increases in ADC/AGMAT mRNA levels and in the translation of AGMAT mRNA among conceptuses in MAO-ODC1 knockdown compensated for the loss of ODC1, supporting polyamine synthesis from arginine and accounting for the normal and abnormal phenotypes of conceptuses. We conclude that the majority of polyamine synthesis is by the conventional ODC1-dependent pathway (arginine-ornithine-putrescine) and that deficiencies in ODC1 result in increased activity of the rescue ADC/AGMAT-dependent pathway (arginine-agmatine-putrescine) for production of polyamines. The presence of an alternative ADC/AGMAT pathway for converting arginine into putrescine is functionally important for supporting survival and development of mammalian conceptuses.

Health effects and occurrence of dietary polyamines: a review for the period 2005-mid 2013

This review continues a previous one (Kalač & Krausová, 2005). Dietary polyamines spermidine and spermine participate in an array of physiological roles with both favourable and injurious effects on human health. Dieticians thus need plausible information on their content in various foods. The data on the polyamine contents in raw food materials increased considerably during the reviewed period, while information on their changes during processing and storage have yet been fragmentary and inconsistent. Spermidine and spermine originate mainly from raw materials. Their high contents are typical particularly for inner organs and meat of warm-blooded animals, soybean and fermented soybean products and some mushroom species. Generally, polyamine contents range widely within the individual food items.

Study of the effects of oral zinc supplementation on peroxynitrite levels, arginase activity and NO synthase activity in seminal plasma of Iraqi asthenospermic patients

BACKGROUND

Low concentrations of nitric oxide (NO) are necessary for the biology and physiology of spermatozoa, but high levels of NO are toxic and have negative effects on sperm functions. Although several studies have considered the relationship between infertility and semen NO concentrations, no study on the effects of asthenospermia treatments such as oral zinc supplementation on concentrations of NO, which are important in fertility, has been reported. Studies have shown that oral zinc supplementation develops sperm count, motility and the physical characteristics of sperm in animals and in some groups of infertile men. The present study was conducted to study the effect of zinc supplementation on the quantitative and qualitative characteristics of semen, along with enzymes of the NO pathway in the seminal plasma of asthenospermic patients.

METHODS

Semen samples were obtained from 60 fertile and 60 asthenozoospermic infertile men of matched age. The subfertile group was treated with zinc sulfate; each participant took two capsules (220 mg per capsule) per day for 3 months. Semen samples were obtained (before and after zinc sulfate supplementation). After liquefaction of the seminal fluid at room temperature, routine semen analyses were performed. The stable metabolites of NO (nitrite) in seminal plasma were measured by nitrophenol assay. Arginase activity and NO synthase activity were measured spectrophotometrically.

RESULTS

Peroxynitrite levels, arginase activity, NO synthase activity and various sperm parameters were compared among fertile controls and infertile patients (before and after treatment with zinc sulfate). Peroxynitrite levels and NO synthase activity were significantly higher in the infertile patients compared to the fertile group. Conversely, arginase activity was significantly higher in the fertile group than the infertile patients. Peroxynitrite levels, arginase activity and NO synthase activity of the infertile patient were restored to normal values after treatment with zinc sulfate. Volume of semen, progressive sperm motility percentage and total normal sperm count were increased after zinc supplementation.

CONCLUSIONS

Treatment of asthenospermic patients with zinc supplementation leads to restored peroxynitrite levels, arginase activity and NO synthase activity to normal values and gives a statistically significant improvement of semen parameters compared with controls.

High-speed tandem mass spectrometric in situ imaging by nanospray desorption electrospray ionization mass spectrometry

Nanospray desorption electrospray ionization (nano-DESI) combined with tandem mass spectrometry (MS/MS), high-resolution mass analysis of the fragment ions (m/Δm = 17 500 at m/z 200), and rapid spectral acquisition enabled simultaneous imaging and identification of a large number of metabolites and lipids from 92 selected m/z windows (±1 Da) with a spatial resolution of better than 150 μm. Mouse uterine sections of implantation sites on day 6 of pregnancy were analyzed in the ambient environment without any sample pretreatment. MS/MS imaging was performed by scanning the sample under the nano-DESI probe at 10 μm/s, while higher-energy collision-induced dissociation (HCD) spectra were acquired for a targeted inclusion list of 92 m/z values at a rate of ∼6.3 spectra/s. Molecular ions and their corresponding fragments, separated by high-resolution mass analysis, were assigned on the basis of accurate mass measurement. Using this approach, we were able to identify and image both abundant and low-abundance isobaric and isomeric species within each m/z window. MS/MS analysis enabled efficient separation and identification of isomeric and isobaric phospholipids that are difficult to separate in full-scan mode. Furthermore, we identified several metabolites associated with early pregnancy and obtained the first 2D images of these molecules.

Aliphatic polyamines in physiology and diseases

Aliphatic polyamines are a family of polycationic molecules derived from decarboxylation of the amino acid ornithine that classically comprise three molecules: putrescine, spermidine and spermine. In-cell polyamine homeostasis is tightly controlled at key steps of cell metabolism. Polyamines are involved in an array of cellular functions from DNA stabilization, and regulation of gene expression to ion channel function and, particularly, cell proliferation. As such, aliphatic polyamines play an essential role in rapidly dividing cells such as in the immune system and digestive tract. Because of their role in cell proliferation, polyamines are also involved in carcinogenesis, prompting intensive research into polyamine metabolism as a target in cancer therapy. More recently, another aliphatic polyamine, agmatine, the decarboxylated derivative of arginine, has been identified as a neurotransmitter in mammals, and investigations have focused on its effects in the CNS, notably as a neuroprotector in brain injury.

Pharmacological potential of biogenic amine-polyamine interactions beyond neurotransmission

Histamine, serotonin and dopamine are biogenic amines involved in intercellular communication with multiple effects on human pathophysiology. They are products of two highly homologous enzymes, histidine decarboxylase and l-aromatic amino acid decarboxylase, and transmit their signals through different receptors and signal transduction mechanisms. Polyamines derived from ornithine (putrescine, spermidine and spermine) are mainly involved in intracellular effects related to cell proliferation and death mechanisms. This review summarizes structural and functional evidence for interactions between components of all these amine metabolic and signalling networks (decarboxylases, transporters, oxidases, receptors etc.) at cellular and tissue levels, distinct from nervous and neuroendocrine systems, where the crosstalk among these amine-related components can also have important pathophysiological consequences. The discussion highlights aspects that could help to predict and discuss the effects of intervention strategies.

Deficiency of ovarian ornithine decarboxylase contributes to aging-related egg aneuploidy in mice

It has been known for more than four decades that during mammalian estrous cycles, luteinizing hormone stimulates a transitory rise in the ovaries of ornithine decarboxylase (ODC) activity and its enzymatic product putrescine, concurrent with oocyte maturation in vivo. Inhibition of this transitory ODC/putrescine rise, however, does not appear to affect oocyte maturation or ovulation. Using several mouse models and combining in vitro and in vivo approaches, we demonstrated that deficiency of ODC during oocyte maturation is correlated with increased levels of egg aneuploidies. These results suggest that the transitory ovarian ODC rise in late proestrus is important for ensuring proper chromosome segregation during oocyte maturation. Older mice (8 months of age) exhibited about 1/3 that of young mice in LH-stimulated ovarian ODC activity and a corresponding increase in egg aneuploidies. Moreover, a combination of putrescine supplementation in mouse drinking water leading up to oocyte retrieval and in oocyte maturation medium reduced egg aneuploidies of the older mice from 12.7% to 5.3%. Therefore, ovarian ODC deficiency might be an important etiology of maternal aging-related aneuploidies, and peri-ovulatory putrescine supplementation might reduce the risk of aneuploid conceptions in older women.

Spermidine promotes mating and fertilization efficiency in model organisms

Spermidine is a naturally occurring polyamine involved in multiple biological processes, including DNA metabolism, autophagy and aging. Like other polyamines, spermidine is also indispensable for successful reproduction at several stages. However, a direct influence on the actual fertilization process, i.e., the fusion of an oocyte with a spermatocyte, remains uncertain. To explore this possibility, we established the mating process in the yeast Saccharomyces cerevisiae as a model for fertilization in higher eukaryotes. During human fertilization, the sperm capacitates and the acrosome reaction is necessary for penetration of the oocyte. Similarly, sexually active yeasts form a protrusion called "shmoo" as a prerequisite for mating. In this study, we demonstrate that pheromone-induced shmoo formation requires spermidine. In addition, we show that spermidine is essential for mating in yeast as well as for egg fertilization in the nematode Caenorhabditis elegans. In both cases, this occurs independently from autophagy. In synthesis, we identify spermidine as an important mating component in unicellular and multicellular model organisms, supporting an unprecedented evolutionary conservation of the mechanisms governing fertilization-related cellular fusion.

Novel molecular targets associated with testicular dysgenesis induced by gestational exposure to diethylhexyl phthalate in the rat: a role for estradiol

Significant research has been focused on phthalate-induced alterations in male reproductive development. Studies on rodents have prompted the notion that a syndrome exists in the human male which includes phenotypic alterations such as hypospadias, cryptorchidism, poor semen quality, and even testicular cancer. Each phenotype in this 'testicular dysgenesis syndrome' is predicated on reduction in testosterone production by the fetal Leydig cell. We sought to examine the relationship between dysgenesis and steroidogenic capacity in the fetal rat testis more stringently by incorporating lower exposures than those typically used, conducting a comprehensive, non-targeted quantitative evaluation of the fetal testis proteome, and relating alterations in individual proteins to the capacity of the fetal Leydig cell to produce testosterone, and histopathology of the fetal testis. Pregnant dams were dosed orally from gestation day (GD) 13-19 with 0, 10, or 100 mg diethylhexyl phthalate (DEHP)/kg body weight per day. Each endpoint was represented by 16l. Clustering of Leydig cells occurred before any significant decrease in the capacity of the GD19 Leydig cell to produce testosterone. At 100 mg DEHP/kg, testosterone production was reduced significantly, Leydig cell clusters became quite large, and additional dysgenetic changes were observed in the fetal testis. Of 23 proteins whose expression was altered significantly at both DEHP exposure levels, seven were found to be correlated with and predictive of the quantified endpoints. None of these proteins have been previously implicated with DEHP exposure. Notably, pathway analysis revealed that these seven proteins fit a pathway network in which each is regulated directly or indirectly by estradiol.

Pivotal Advance: Arginase-1-independent polyamine production stimulates the expression of IL-4-induced alternatively activated macrophage markers while inhibiting LPS-induced expression of inflammatory genes

In macrophages, basal polyamine (putrescine, spermidine, and spermine) levels are relatively low but are increased upon IL-4 stimulation. This Th2 cytokine induces Arg1 activity, which converts arginine into ornithine, and ornithine can be decarboxylated by ODC to produce putrescine, which is further converted into spermidine and spermine. Recently, we proposed polyamines as novel agents in IL-4-dependent E-cadherin regulation in AAMs. Here, we demonstrate for the first time that several, but not all, AAM markers depend on polyamines for their IL-4-induced gene and protein expression and that polyamine dependency of genes relies on the macrophage type. Remarkably, Arg1-deficient macrophages display rather enhanced IL-4-induced polyamine production, suggesting that an Arg1-independent polyamine synthesis pathway may operate in macrophages. On the other side of the macrophage activation spectrum, LPS-induced expression of several proinflammatory genes was increased significantly in polyamine-depleted CAMs. Overall, we propose Arg1 independently produced polyamines as novel regulators of the inflammatory status of the macrophage. Indeed, whereas polyamines are needed for IL-4-induced expression of several AAM mediators, they inhibit the LPS-mediated expression of proinflammatory genes in CAMs.