Copper Metabolism Disorders Affect Testes Structure and Gamete Quality in Male Mice

Protective effects of polysaccharide extracted from green alga Chaetomorpha linum against zinc and copper-induced testicular toxicity in male mice

This study aimed to investigate the effects of copper (CuSO4) and zinc (ZnSO4) overload on male reproductive toxicity and the potential of a polysaccharide extracted from green alga Chaetomorpha linum (PS) in mitigating their toxicities. Adult male mice strain of 25 ± 2 g of weight was subdivided into eight groups. Group 1 served as control; group 2 received PS (200 mg/kg), and groups 3 and 4 received intraperitoneally zinc (60 mg/kg b.w) and copper (33 mg/kg b.w), respectively. Group 5 received both zinc (60 mg/kg b.w) and copper (33 mg/kg b.w), group 6 received zinc (60 mg/kg b.w) associated with PS (200 mg/kg), group 7 received copper (33 mg/kg b.w) associated with PS (200 mg/kg), and group 8 received zinc (60 mg/kg b.w) and copper (33 mg/kg b.w) associated with PS (200 mg/kg). Results suggested that ZnSO4 and CuSO4 significantly decreased the functional sperm parameters. Furthermore, extended exposure to these elements increased oxidative stress biomarkers, including malondialdehyde (MDA) as a measure of lipid peroxidation and advanced oxidation protein products (AOPP) indicating protein oxidative damage. This process also reduces the activity of antioxidant enzymes such as glutathione (GSH) and glutathione peroxidase (GPx), which neutralize and catalyze free radicals. Histopathological changes in mice testis were also studied. However, the co-treatments with PS significantly reduced these effects and promoted the reproductive parameters in male mice. In conclusion, PS exhibited protective effects against zinc and copper-induced reproductive toxicity, making it a potential adjuvant treatment for testicular toxicity.

Trace and essential elements as vital components to improve the performance of the male reproductive system: Implications in cell signaling pathways

Successful male fertilization requires the main processes such as normal spermatogenesis, sperm capacitation, hyperactivation, and acrosome reaction. The progress of these processes depends on some endogenous and exogenous factors. So, the optimal level of ions and essential and rare elements such as selenium, zinc, copper, iron, manganese, calcium, and so on in various types of cells of the reproductive system could affect conception and male fertility rates. The function of trace elements in the male reproductive system could be exerted through some cellular and molecular processes, such as the management of active oxygen species, involvement in the action of membrane channels, regulation of enzyme activity, regulation of gene expression and hormone levels, and modulation of signaling cascades. In this review, we aim to summarize the available evidence on the role of trace elements in improving male reproductive performance. Also, special attention is paid to the cellular aspects and the involved molecular signaling cascades.

Decreased Expression of the Slc31a1 Gene and Cytoplasmic Relocalization of Membrane CTR1 Protein in Renal Epithelial Cells: A Potent Protective Mechanism against Copper Nephrotoxicity in a Mouse Model of Menkes Disease

Kidneys play an especial role in copper redistribution in the organism. The epithelial cells of proximal tubules perform the functions of both copper uptake from the primary urine and release to the blood. These cells are equipped on their apical and basal membrane with copper transporters CTR1 and ATP7A. Mosaic mutant mice displaying a functional dysfunction of ATP7A are an established model of Menkes disease. These mice exhibit systemic copper deficiency despite renal copper overload, enhanced by copper therapy, which is indispensable for their life span extension. The aim of this study was to analyze the expression of Slc31a1 and Slc31a2 genes (encoding CTR1/CTR2 proteins) and the cellular localization of the CTR1 protein in suckling, young and adult mosaic mutants. Our results indicate that in the kidney of both intact and copper-injected 14-day-old mutants showing high renal copper content, CTR1 mRNA level is not up-regulated compared to wild-type mice given a copper injection. The expression of the Slc31a1 gene in 45-day-old mice is even reduced compared with intact wild-type animals. In suckling and young copper-injected mutants, the CTR1 protein is relocalized from the apical membrane to the cytoplasm of epithelial cells of proximal tubules, the process which prevents copper transport from the primary urine and, thus, protects cells against copper toxicity.

Changes in heavy metal levels, reproductive characteristics, oxidative stress markers and testicular apoptosis in rams raised around thermal power plant

Male reproductive dysfunction is one of the damages in the organism caused by heavy metals. In this study, it was aimed to investigate the changes in heavy metal levels in serum and testicular tissue, and serum hormone levels, epididymal spermatozoa characteristics, tissue oxidative stress levels, testicular histology and testicular apoptosis level in rams raised in remote and near regions of a thermal power plant. A total of 75 rams were divided into 3 groups according to the regions, where they were born and raised, being far [250 km distance, group 1 (control), n = 25], close (20 km distance, group 2, n = 25) and very close (10 km distance, group 3, n = 25) to the thermal power plant. The blood along with testis and epididymis tissues was taken from the animals after slaughtering. In addition, soil and water heavy metal analyzes were also performed. The highest levels of serum Al, Cr, As, Ag, Sn and testicular Al, V, Ni, Ag, Cd, Cr, As, Pb, and the lowest levels of serum Cu, testicular Cu and Zn were determined in group 3 compared to control. Soil and water heavy metal results were similar to those found in serum and testis. The lowest serum testosterone level, tissue glutathione-peroxidase and catalase activities, spermatozoon concentration, and the highest tissue malondialdehyde level, dead spermatozoon rate, Bax apoptotic protein expression level and Bax/Bcl-2 rate alongside some testicular histopathological lesions were found in group 3 in comparison to control. Significant correlations were determined between some heavy metal levels and some parameters measured. As a result, heavy metals accumulate in the soil and water in the region close to the thermal power plant. The endocrine and exocrine reproductive potentials of rams born and grown in these regions were clearly damaged by the increased testicular heavy metals due to water drank and herbs consumed.

Chrysin and flunixin meglumine mitigate overloaded copper-induced testicular and spermatological damages via modulation of oxidative stress and apoptosis in rats

This study aimed to evaluate the possible protective actions of chrysin and flunixine meglumine on testicular and spermatological injuries experimentally stimulated by copper. We separated 36 male Sprague-Dawley rats into six equal groups: control, chrysin, flunixine meglumine, copper, copper +chrysin and copper +flunixine meglumine. Chrysin (50 mg/kg/bw/po), flunixine meglumine (2.2 mg/kg/bw/ip) and copper (500 mg/kg/bw/po) were administered day to day for 21 days. Copper administration caused significant morphological, physiological and biochemical alterations compared to the control group, which are as follows: production of oxidative stress, thanks to rise in testis lipid peroxidation and fall in antioxidant enzyme concentrations, decrease in sperm quality and increase in morphologic sperm abnormalities, suppression of spermatogenesis and prominent alterations in the testis histomorphology and induction of apoptosis in the testis tissues. On the other hand, compared to the copper group, treatment with chrysin or flunixine meglumine significantly attenuated these alterations. In conclusion, chrysin and flunixine meglumine have benefits such as antioxidant, antiapoptotic and anti-inflammatory against copper-induced testicular and spermatological damages in rats via the modulation of oxidative stress and apoptosis. Consequently, chrysin is a natural product which has comparable therapeutic actions to flunixine meglumine on the male reproductive system.

Negative metal bioaccumulation impacts on systemic shark health and homeostatic balance

Contamination by metals is among the most pervasive anthropogenic threats to the environment. Despite the ecological importance of marine apex predators, the potential negative impacts of metal bioaccumulation and biomagnification on the health of higher trophic level species remains unclear. To date, most toxicology studies in sharks have focused on measuring metal concentrations in muscle tissues associating human consumption and food safety, without further investigating potential impacts on shark health. To help address this knowledge gap, the present study evaluated metal concentrations in the gills, muscle, liver and rectal gland of coastal sharks opportunistically sampled from Brazilian waters and tested for potential relationships between metal bioaccumulation and general shark health and homeostatic balance metrics. Results revealed high metal concentrations in all four tissue types, with levels varying in relation to size, sex, and life-stage. Metal concentrations were also associated with serum biomarkers (urea, lactate, ALT, triglycerides, alkaline phosphatase, and phosphorus) and body condition, suggesting potential negative impacts on organismal health.

Molecular Regulation of Copper Homeostasis in the Male Gonad during the Process of Spermatogenesis

Owing to its redox properties, copper is a cofactor of enzymes that catalyze reactions in fundamental metabolic processes. However, copper-oxygen interaction, which is a source of toxic oxygen radicals generated by the Fenton reaction, makes copper a doubled-edged-sword in an oxygen environment. Among the microelements influencing male fertility, copper plays a special role because both copper deficiency and overload in the gonads worsen spermatozoa quality and disturb reproductive function in mammals. Male gametes are produced during spermatogenesis, a multi-step process that consumes large amounts of oxygen. Germ cells containing a high amount of unsaturated fatty acids in their membranes are particularly vulnerable to excess copper-mediated oxidative stress. In addition, an appropriate copper level is necessary to initiate meiosis in premeiotic germ cells. The balance between essential and toxic copper concentrations in germ cells at different stages of spermatogenesis and in Sertoli cells that support their development is handled by a network of copper importers, chaperones, recipient proteins, and exporters. Here, we describe coordinated regulation/functioning of copper-binding proteins expressed in germ and Sertoli cells with special emphasis on copper transporters, copper transporting ATPases, and SOD1, a copper-dependent antioxidant enzyme. These and other proteins assure copper bioavailability in germ cells and protection against copper toxicity.

Copper(II) Binding by the Earliest Vertebrate Gonadotropin-Releasing Hormone, the Type II Isoform, Suggests an Ancient Role for the Metal

In vertebrate reproductive biology copper can influence peptide and protein function both in the pituitary and in the gonads. In the pituitary, copper binds to the key reproductive peptides gonadotropin-releasing hormone I (GnRH-I) and neurokinin B, to modify their structure and function, and in the male gonads, copper plays a role in testosterone production, sperm morphology and, thus, fertility. In addition to GnRH-I, most vertebrates express a second isoform, GnRH-II. GnRH-II can promote testosterone release in some species and has other non-reproductive roles. The primary sequence of GnRH-II has remained largely invariant over millennia, and it is considered the ancestral GnRH peptide in vertebrates. In this work, we use a range of spectroscopic techniques to show that, like GnRH-I, GnRH-II can bind copper. Phylogenetic analysis shows that the proposed copper-binding ligands are retained in GnRH-II peptides from all vertebrates, suggesting that copper-binding is an ancient feature of GnRH peptides.

Levels of Macro- and Trace Elements and Select Cytokines in the Semen of Infertile Men

The current study evaluated levels of macro-/trace elements, select cytokines, and sperm quality, in the semen of men with abnormal spermograms. The study population of men with abnormal spermograms was divided into three groups, i.e., oligospermic, asthenozoospermic, and oligoasthenozoospermic. The control group was fertile men with normal semen parameters. Analyses showed that in comparison with that in the semen of the fertile men, levels of calcium, magnesium, and selenium were significantly lower in men with all three groups. Semen levels of zinc were significantly lower in men with asthenospermia as compared with that in control. GGT (gamma-glutamyltranspeptidase) activity in semen was significantly higher in men in any of the three states as compared with that seen in control semen. In contrast, semen ALT (alanine aminotransferase) activity was reduced in men with any of these abnormalities compared with that in the controls. Semen cholesterol levels were significantly lower in men with asthenospermia as compared with control semen. Of all the measured cytokines, only IL-5 levels were reduced in the semen of the men with any of the conditions as compared with control semen. The semen of infertile males is characterized by reduced levels of calcium, magnesium, and trace metals such as zinc and selenium. The study also indicated that measures of cholesterol and of GGT/ALT activities could serve as supplementary parameters indicative of semen quality. Further investigations are needed to clarify the role of the measured parameters in sperm physiology.

Molecular machinery providing copper bioavailability for spermatozoa along the epididymial tubule in mouse

Progressive functional maturation of spermatozoa is completed during the transit of these cells through the epididymis, a tubule structure connecting a testicle to a vas deferens. Epididymal epithelial cells by means of their secretory and absorptive functions determine a highly specialized luminal microenvironment containing multiple organic and inorganic components. The latter include copper ions, which due to their redox properties are indispensable for critical homeostatic processes occurring in spermatozoa floating in different part of epididymis but can be potentially toxic. Main purpose of our study was to determine epididymal region-dependent expression and localization of copper transporters ensuring a tight control of copper concentration in epididymal fluid. We also aimed at identifying proteins responsible for copper uptake by spermatozoa and verifying whether this process is coordinated with copper supply to superoxide dismutase 1 (SOD1), a copper-dependent antioxidant enzyme. Our study identifies two ATPases-ATP7A, ATP7B and Slc31a1, major copper importers/exporters depending on their differential expression on epididymal polarized epithelial cells of the caput, corpus, and cauda. Next, ceruloplasmin seems to be a chief protein transporting copper in the epididymal fluid and providing this biometal to spermatozoa. The entry of copper to germ cells is mediated by Slc31a1 and is correlated with both expressions of copper chaperone for superoxide dismutase (CCS), copper chaperone directly providing copper ions to SOD1 and with the expression and activity of the latter. Our results outline a network of cooperating copper binding proteins expressed in epididymal epithelium and in spermatozoa that orchestrate bioavailability of this microelement for gametes and protect them against copper toxicity.

Chronic Copper Exposure Induces Hypospermatogenesis in Mice by Increasing Apoptosis Without Affecting Testosterone Secretion

Chronic copper exposure impaired spermatogenesis in adult male mice. The aim of this study was to determine whether chronic copper exposure can induce apoptosis of testicular cell and hypospermatogenesis via disturbing testosterone synthesis in adult male mice. In the present study, sixty CD-1 male mice were randomly divided into four groups, and were continuously administered for 8 weeks by oral gavage with copper sulfate at a dose of 0, 25, 100, and 150 mg/kg/day, respectively. We determined the content of serum and testicular copper, testicular coefficient, testicular histopathology, sperm count and motility, the mRNA and protein levels of Caspase-3, Bax, and Bcl-2, Leydig cell count, testosterone content, testosterone synthetase, and testosterone synthesis-related genes. The results showed that the copper levels in serum increased in a dose-dependent manner, and the copper levels in testes were significantly related to serum copper levels. Male mice given copper sulfate 100 and 150 dosage groups showed significant decreased in sperm motility and sperm number as well as increased in testes damage, and there was no significant change in testicular coefficient in the four groups. The mRNA levels of Bcl-2 decreased and Caspase-3 increased in 150 dosage group, and Bax increased in two higher dosage groups. Meanwhile, Caspase-3 and Bax proteins increased in 150 dosage group, and Bcl-2 protein decreased in three copper treatment groups. Nevertheless, there were no differences on the levels of testosterone content and testosterone synthetase of 3β-HSD, 17β-HSD, 17α-Hyd, and 20α-Hyd, mRNA levels of Cyp11a1, Cyp17a1, and Star, and quantity of Leydig cells in four groups. Overall, these data showed that chronic copper exposure led to copper residues in the testes, and the doses of 100 and 150 mg/kg/day copper sulfate may induce hypospermatogenesis by increasing apoptosis without affecting testosterone secretion.

Copper oxychloride-induced testicular damage of adult albino rats and the possible role of curcumin in healing the damage

The current research study investigated the effect of 80 mg/kg b.wt./day curcumin (cur) against 50, 100, and 200 mg/kg copper oxychloride (COC) for 90 days induced testicular damage using histological, ultrastructural, and biochemical techniques. Histological and cellular abnormalities have been noted in seminiferous tubules of COC-treated group and treated group with Cur- and COC-treated group. The biochemical result showed that serum testosterone was significantly decreased in COC-treated rats and Cur COC-treated rats compared with the control groups. Testes copper content and malondialdehyde was increased, whereas the testes total antioxidant, manganese, ferrous, and zinc levels were decreased (p ≥ 0.05) compared to the control groups. In conclusion, the present work reported that the treatment of rats with 80 mg/kg body weight curcumin prior to treatment with COC did not mitigate the deleterious effects of COC and manifested no signs of protection.

Copper transporter 1 (CTR1) expression by mouse testicular germ cells, but not Sertoli cells, is essential for functional spermatogenesis

An imbalance in copper (Cu) tissue homeostasis has a degenerative effect on spermatogenesis and male fertility. The high-affinity Cu transporter 1 (CTR1; SLC31A1) is the major protein responsible for Cu acquisition in eukaryotes and is highly expressed in mouse testes. Studies on yeast and Drosophila have demonstrated the conserved essential function of Cu and CTR1 for meiosis and fertility, implying that CTR1 may play an essential function in mammalian spermatogenesis. In mice, spermatogenesis takes place within the seminiferous epithelium, where tight junctions between somatic Sertoli cells (SCs) create a specialized microenvironment for the development of meiotic germ cells (GCs) by tightly regulating the free transport of metabolites and ions to reach these cells. Here, it is demonstrated that within the seminiferous epithelium, CTR1 is expressed on the membrane of primary pachytene spermatocytes and SCs. To examine the physiological significance of CTR1 in spermatogenesis, mice with a GC-specific (Ctr1ΔGC) and SC-specific (Ctr1ΔSC) disruption of the Ctr1 gene were generated. The testis of Ctr1ΔGC mice exhibits a severe progressive loss of GCs starting at postnatal day (PND) 28 leading to testis hypoplasia by adulthood. No spermatogenic recovery was observed in Ctr1ΔGC testis beyond PND 41, despite the presence of FOXO-1 expressing undifferentiated spermatogonial cells. However, Ctr1ΔSC mice displayed functional spermatogenesis and were fertile, even though testicular Cu levels and Cu-dependent cellular activities were significantly reduced. These results reveal, for the first time, the importance of CTR1 expression by GCs for maintaining functional spermatogenesis.

Disulfiram enhanced delivery of orally administered copper into the central nervous system in Menkes disease mouse model

INTRODUCTION

Menkes disease (MD) is an X-linked recessive disorder caused by dysfunction of a copper-transporting protein, leading to severe neurodegeneration in early childhood. We investigated whether a lipophilic copper chelator, disulfiram, could enhance copper absorption from the intestine and transport copper across the blood-brain barrier in MD model mice.

METHODS

Wild type and MD model mice were pretreated with disulfiram for 30 min before oral administration of ⁶⁴CuCl₂. Each organ was sequentially analyzed for radioactivity with γ counting. Copper uptake into the brain parenchyma was assessed by ex vivo autoradiography.

RESULTS

In wild type mice, orally administered copper was initially detected in the intestine within 2 h, reaching a maximum level in the liver (19.6 ± 3.8 percentage injected dose per gram [%ID/g]) at 6 h. In MD model mice, the copper reached the maximum level in the liver (5.3 ± 1.5 %ID/g) at 4 h, which was lower than that of wild type mice (19.0 ± 7.4 %ID/g) (P < 0.05). Pretreatment of disulfiram in MD model mice increased the copper level in the brain (0.59 ± 0.28 %ID/g) at 24 h compared with MD model mice without disulfiram (0.07 ± 0.05 %ID/g) (P < 0.05). Ex vivo autoradiography revealed that high levels of copper uptake was observed in the cerebral cortex upon disulfiram pretreatment.

CONCLUSION

Our data demonstrated that disulfiram enhanced the delivery of orally administered copper into the central nervous system in MD model mice. The administration of disulfiram will enable patients to avoid unpleasant subcutaneous copper injection in the future.

Atp7a and Atp7b regulate copper homeostasis in developing male germ cells in mice

The maintenance of copper homeostasis is critical for all cells. As learned from mice with disturbed copper metabolism, this trace element is also important for spermatogenesis. The experiments conducted in yeasts have demonstrated that appropriate copper level must be preserved to enable meiosis progression; however, increased copper level is toxic for cells. This study aims to analyze the expression profile of Atp7a and Atp7b and other genes encoding copper-related proteins during spermatogenesis in mice. Using the transcripts and protein detection techniques, we demonstrate that within seminiferous tubuli, ATP7A is mainly present in early meiotic germ cells (leptotene to pachytene spermatocytes) and in Sertoli cells (SCs). During spermatogenesis, the progression Atp7a expression profile corresponds to Slc31a1 (encoding copper importer CTR1) and Atox1 (encoding chaperon protein, which delivers copper from CTR1 to ATP7A and ATP7B) expression, suggesting that male germ cells retrieve copper and ATP7A protects them from copper overdose. In contrast, ATP7B protein is observed in SCs and near elongated spermatids; thus, its function seems to be related to copper extraction during spermiogenesis. This is the first study to give a comprehensive view on the activity of copper-related genes during spermatogenesis in mice.

Copper therapy reduces intravascular hemolysis and derepresses ferroportin in mice with mosaic mutation (Atp7amo-ms): An implication for copper-mediated regulation of the Slc40a1 gene expression

Mosaic mutant mice displaying functional dysfunction of Atp7a copper transporter (the Menkes ATPase) are an established animal model of Menkes disease and constitute a convenient tool for investigating connections between copper and iron metabolisms. This model allows to explore changes in iron metabolism in suckling mutant mice suffering from systemic copper deficiency as well as in young and adult ones undergone copper therapy, which reduces lethal effect of the Atp7a gene mutation. Our recent study demonstrated that 14-day-old mosaic mutant males display blood cell abnormalities associated with intravascular hemolysis, and show disturbances in the functioning of the hepcidin-ferroportin regulatory axis, which controls systemic iron homeostasis. We thus aimed to check whether copper supplementation recovers mutants from hemolytic insult and rebalance systemic iron regulation. Copper supplementation of 14-day-old mosaic mutants resulted in the reestablishment of hematological status, attenuation of hepicidin and concomitant induction of the iron exporter ferroportin/Slc40a1 expression in the liver, down-regulated in untreated mutants. Interestingly, treatment of wild-type males with copper, induced hepcidin-independent up-regulation of ferroportin protein level in hepatic macrophages in both young and adult (6-month-old) animals. Stimulatory effect of copper on ferroportin mRNA and protein levels was confirmed in bone marrow-derived macrophages isolated from both wild-type and mosaic mutant males. Our study indicates that copper is an important player in the regulation of the Slc40a1 gene expression.

Functional significance of the sex chromosomes during spermatogenesis

Mammalian sex chromosomes arose from an ordinary pair of autosomes. Over hundreds of millions of years, they have evolved into highly divergent X and Y chromosomes and have become increasingly specialized for male reproduction. Both sex chromosomes have acquired and amplified testis-specific genes, suggestive of roles in spermatogenesis. To understand how the sex chromosome genes participate in the regulation of spermatogenesis, we review genes, including single-copy, multi-copy, and ampliconic genes, whose spermatogenic functions have been demonstrated in mouse genetic studies. Sex chromosomes are subject to chromosome-wide transcriptional silencing in meiotic and postmeiotic stages of spermatogenesis. We also discuss particular sex-linked genes that escape postmeiotic silencing and their evolutionary implications. The unique gene contents and genomic structures of the sex chromosomes reflect their strategies to express genes at various stages of spermatogenesis and reveal the driving forces that shape their evolution.Free Chinese abstract: A Chinese translation of this abstract is freely available at http://www.reproduction-online.org/content/149/6/R265/suppl/DC1.Free Japanese abstract: A Japanese translation of this abstract is freely available at http://www.reproduction-online.org/content/149/6/R265/suppl/DC2.

Mottled Mice and Non-Mammalian Models of Menkes Disease

Menkes disease is a multi-systemic copper metabolism disorder caused by mutations in the X-linked ATP7A gene and characterized by progressive neurodegeneration and severe connective tissue defects. The ATP7A protein is a copper (Cu)-transporting ATPase expressed in all tissues and plays a critical role in the maintenance of copper homeostasis in cells of the whole body. ATP7A participates in copper absorption in the small intestine and in copper transport to the central nervous system (CNS) across the blood-brain-barrier (BBB) and blood–cerebrospinal fluid barrier (BCSFB). Cu is essential for synaptogenesis and axonal development. In cells, ATP7A participates in the incorporation of copper into Cu-dependent enzymes during the course of its maturation in the secretory pathway. There is a high degree of homology (>80%) between the human ATP7A and murine Atp7a genes. Mice with mutations in the Atp7a gene, called mottled mutants, are well-established and excellent models of Menkes disease. Mottled mutants closely recapitulate the Menkes phenotype and are invaluable for studying Cu-metabolism. They provide useful models for exploring and testing new forms of therapy in Menkes disease. Recently, non-mammalian models of Menkes disease, Drosophila melanogaster and Danio rerio mutants were used in experiments which would be technically difficult to carry out in mammals.

Copper-transporting ATPase is important for malaria parasite fertility

Homeostasis of the trace element copper is essential to all eukaryotic life. Copper serves as a cofactor in metalloenzymes and catalyses electron transfer reactions as well as the generation of potentially toxic reactive oxygen species. Here, we describe the functional characterization of an evolutionarily highly conserved, predicted copper-transporting P-type ATPase (CuTP) in the murine malaria model parasite Plasmodium berghei. Live imaging of a parasite line expressing a fluorescently tagged CuTP demonstrated that CuTP is predominantly located in vesicular bodies of the parasite. A P. berghei loss-of-function mutant line was readily obtained and showed no apparent defect in in vivo blood stage growth. Parasite transmission through the mosquito vector was severely affected, but not entirely abolished. We show that male and female gametocytes are abundant in cutp⁻ parasites, but activation of male microgametes and exflagellation were strongly impaired. This specific defect could be mimicked by addition of the copper chelator neocuproine to wild-type gametocytes. A cross-fertilization assay demonstrated that female fertility was also severely abrogated. In conclusion, we provide experimental genetic and pharmacological evidence that a healthy copper homeostasis is critical to malaria parasite fertility of both genders of gametocyte and, hence, to transmission to the mosquito vector.

Iron excess disturbs metabolic status and relative gonad mass in rats on high fat, fructose, and salt diets

The aim of this study was to assess the metabolic and physiological changes in rats fed a diet high in fat, fructose, and salt, and with excess iron level. Mineral status was also estimated. Wistar rats were assigned to groups fed either a standard control diet (C) or a diet high in fat, fructose, and salt. The noncontrol diets contained either normal (M) or high level (MFe) of iron. After 6 weeks, the length and weight of the rats were measured, and the animals were euthanized. The kidneys and gonads were collected, and blood samples were taken. Serum levels of insulin, nitric oxide, and iron were measured. The iron, zinc, copper, and calcium concentrations of tissues were determined. It was found that the M diet led to a significant increase in the relative kidney mass of the rats compared with the control group. Among the rats fed the M diet, markedly higher serum level of iron and lower levels of zinc and copper were observed in tissues, while significantly higher calcium levels were found in the gonads. The MFe diet resulted in decreased obesity index, insulin level, and nitric oxide serum concentration in the rats, when compared with both the M and C diets. The high iron level in the modified diet increased the relative mass of the gonads. The excess iron level in the diet disturbed the zinc, copper, and calcium status of tissues. The decrease in insulin and nitric oxide in rats fed the diet high in iron, fat, fructose, and salt was associated with disorders of zinc, copper, and calcium status, as well as with an increase in the relative mass of the gonads.

Prenatal treatment of mosaic mice (Atp7a mo-ms) mouse model for Menkes disease, with copper combined by dimethyldithiocarbamate (DMDTC)

Menkes disease is a fatal neurodegenerative disorder in infants caused by mutations in the gene ATP7A which encodes a copper (Cu) transporter. Defects in ATP7A lead to accumulated copper in the small intestine and kidneys and to copper deficiencies in the brain and the liver. The copper level in the kidney in postnatal copper-treated Menkes patients may reach toxic levels. The mouse model, mosaic Atp7a ^mo-ms recapitulates the Menkes phenotype and die about 15.75±1.5 days of age. In the present study we found that prenatal treatment of mosaic murine fetuses throughout gestation days 7, 11, 15 and 18 with a combination of CuCl₂ (50 mg/kg) and dimethyldithiocarbamate (DMDTC) (280 mg/kg) leads to an increase in survival to about 76±25.3 days, whereas treatment with CuCl₂ alone (50 mg/kg) only leads to survival for about 21 days ±5 days. These copper-DMDTC treated mutants showed an improved locomotor activity performance and a gain in body mass. In contrast to treatment with CuCl₂ alone, a significant increase in the amount of copper was observed in the brain after prenatal copper-DMDTC treatment as well as a decrease in the amount of accumulated copper in the kidney, both leading towards a normalization of the copper level. Although copper-DMDTC prenatal treatment only leads to a small increase in the sub-normal copper concentration in the liver and to an increase of copper in the already overloaded small intestine, the combined results suggest that prenatal copper-DMDTC treatment also should be considered for humans.

Mfc1 is a novel copper transporter during meiosis

Meiosis is a specialized cell division process by which diploid germ line cells generate haploid gametes, which are required for sexual reproduction. During this process, several micronutrients are required, including copper ions. Despite important roles for copper-dependent proteins during meiosis, their mechanisms of action remain poorly understood. In a recently publication, we reported the discovery of Mfc1, the first example ever reported of a meiosis-specific copper transporter. Although Mfc1 did not exhibit any significant amino acid sequence similarities with members of the Ctr family of copper transporters, it harbored putative copper coordination motifs. Microarray data showed that mfc1⁺ was the most highly induced of all meiotic genes detected under copper-limiting conditions. Analysis of Mfc1 localization during meiosis revealed that it localized at the forespore membrane during middle and late phases of the meiotic program. Interestingly, live-cell copper imaging using a copper-binding tracker revealed accumulation of copper ions into the forespore in wild-type cells. In contrast, mutant cells lacking Mfc1 displayed an intracellular distribution of copper ions that was dispersed throughout the ascospores without any marked preference for the forespore. We propose that Mfc1 is required to mobilize copper into the forespore, thereby providing copper to copper-requiring enzymes of the developing spores.