Arundic Acid (ONO-2506) Attenuates Neuroinflammation and Prevents Motor Impairment in Rats with Intracerebral Hemorrhage.

Intracerebral hemorrhage (ICH) is a severe stroke subtype caused by the rupture of blood vessels within the brain. Increased levels of S100B protein may contribute to neuroinflammation after ICH through activation of astrocytes and resident microglia, with the consequent production of proinflammatory cytokines and reactive oxygen species (ROS). Inhibition of astrocytic synthesis of S100B by arundic acid (AA) has shown beneficial effects in experimental central nervous system disorders. In present study, we administered AA in a collagenase-induced ICH rodent model in order to evaluate its effects on neurological deficits, S100B levels, astrocytic activation, inflammatory, and oxidative parameters. Rats underwent stereotactic surgery for injection of collagenase in the left striatum and AA (2 µg/µl; weight × 0.005) or vehicle in the left lateral ventricle. Neurological deficits were evaluated by the Ladder rung walking and Grip strength tests. Striatal S100B, astrogliosis, and microglial activation were assessed by immunofluorescence analysis. Striatal levels of interleukin 1ß (IL-1ß) and tumor necrosis factor α (TNF-α) were measured by ELISA, and the ROS production was analyzed by dichlorofluorescein (DCF) oxidation. AA treatment prevented motor dysfunction, reduced S100B levels, astrogliosis, and microglial activation in the damaged striatum, thus decreasing the release of proinflammatory cytokines IL-1ß and TNF-α, as well as ROS production. Taken together, present results suggest that AA could be a pharmacological tool to prevent the harmful effects of increased S100B, attenuating neuroinflammation and secondary brain damage after ICH.

Arundic Acid (ONO-2506), an Inhibitor of S100B Protein Synthesis, Prevents Neurological Deficits and Brain Tissue Damage Following Intracerebral Hemorrhage in Male Wistar Rats.

Stroke is one of the leading causes of mortality and neurological morbidity. Intracerebral hemorrhage (ICH) has the poorest prognosis among all stroke subtypes and no treatment has been effective in improving outcomes. Following ICH, the observed high levels of S100B protein have been associated with worsening of injury and neurological deficits. Arundic acid (AA) exerts neuroprotective effects through inhibition of astrocytic synthesis of S100B in some models of experimental brain injury; however, it has not been studied in ICH. The aim of this study was to evaluate the effects of intracerebroventricular (ICV) administration of AA in male Wistar rats submitted to ICH model assessing the following variables: reactive astrogliosis, S100B levels, antioxidant defenses, cell death, lesion extension and neurological function. Firstly, AA was injected at different doses (0.02, 0.2, 2 and 20 µg/µl) in the left lateral ventricle in order to observe which dose would decrease GFAP and S100B striatal levels in non-injured rats. Following determination of the effective dose, ICH damage was induced by IV-S collagenase intrastrial injection and 2 µg/µl AA was injected through ICV route immediately before injury. AA treatment prevented ICH-induced neurological deficits and tissue damage, inhibited excessive astrocytic activation and cellular apoptosis, reduced peripheral and central S100B levels (in striatum, serum and cerebrospinal fluid), improved neuronal survival and enhanced the antioxidant defences after injury. Altogether, these results suggest that S100B is a viable target for treating ICH and highlight AA as an interesting strategy for improving neurological outcome after experimental brain hemorrhage.

A novel MYH7 founder mutation causing Laing distal myopathy in Southern Spain.

MYH7 gene mutations are associated with wide clinical and genetic heterogeneity. We report a novel founder mutation in MYH7 in Southern Spain (Andalucía). We studied two index patients and 24 family members from two apparently independent families by physical examination, serum creatine-kinase, muscle MRI, sequencing studies and genetic linkage analysis. Sixteen individuals were heterozygous for a (p.R1560P) variant in the MYH7 gene. Haplotype was consistent with a common ancestor for the two families. The patients displayed the classic Laing distal myopathy phenotype, with hanging first toe as the initial presentation, even in mildly affected patients who declared themselves asymptomatic, although neck flexor weakness was revealed as an early sign in some cases. MRI showed that the sartorius was the first muscle involved, even in two out of three asymptomatic carriers. Our findings support the novel variant p.R1560P in MYH7 as a founder mutation in Andalucía. The early involvement of the sartorius muscle in MRI may be useful as an indicator of affection status.

Glial glutamate transporters expression, glutamate uptake, and oxidative stress in an experimental rat model of intracerebral hemorrhage.

Glial glutamate transporters (EAAT1 and EAAT2), glutamate uptake, and oxidative stress are important players in the pathogenesis of ischemic brain injury. However, the changes in EAAT1 and EAAT2 expression, glutamate uptake and the oxidative profile during intracerebral hemorrhage (ICH) development have not been described. The present study sought to investigate the changes of the above-mentioned variables, as well as the Na+/K+-ATPase and glutamine synthetase activities (as important contributors of glutamate homeostasis) and the percentage of neuronal cells after 6 h, 24 h, 72 h and 7 days of ICH. An injection of 0.2U of bacterial collagenase in the ipsilateral striatum was used to induce ICH in male Wistar rats; naïve animals were used as controls. EAAT1 and EAAT2 expression and glutamate uptake in the ipsilateral striatum were assessed. Additionally, the percentage of MAP2+ cells, Na+/K+-ATPase and GS activities, as well as the oxidative profile were analyzed. It is shown a decrease of EAAT1 expression and glutamate uptake 6 h post-ICH, whereas EAAT2 decreased 72 h after the event; conversely EAAT2 and glutamate uptake were increased after 7 days. The oxidative stress and endogenous defense system exhibited a remarkable response at 72 h of injury. ICH also increased Na+/K+-ATPase activity and selectively decreased GS activity, variables known to be important contributors of glial glutamate transporters activities. Altogether, present findings indicate that ICH induces different temporal EAAT1 and EAAT2 responses, culminating with an imbalance of glutamate uptake capacity, increased oxidative stress and sustained neuronal loss.

Galantamine administration reduces reactive astrogliosis and upregulates the anti-oxidant enzyme catalase in rats submitted to neonatal hypoxia ischemia.

Neonatal hypoxia ischemia (HI) plays a role in the etiology of several neurological pathologies and causes severe sequelae. Acetylcholine is a neurotransmitter in the central nervous system and cholinesterase inhibitors have demonstrated a positive action over HI induced deficits. In order to evaluate the effects of pre and post-hypoxia administrations of galantamine, a cholinesterase inhibitor, in a model of perinatal HI, Wistar rats in the post-natal day 7 (PND7) were subjected to a combination of unilateral occlusion of the right carotid artery with the exposure to a 1h hypoxia. Intraperitoneal injections of galantamine were administered in two different protocols: one pre and other post-hypoxia. The analysis of brain structures volume at PND45 showed that pre-hypoxia galantamine treatment prevented tissue injury to the ipsilesional hippocampus. Also, immunofluorescence showed HI-induced increase in the number of astrocytes that was prevented by pre-hypoxia treatment. Biochemical analysis was performed in the ipsilesional hippocampus at PND8 and revealed that pre-hypoxia galantamine treatment: 1) prevented the neuronal loss induced by HI; 2) reduced the HI-induced hypertrophy of astrocytes; and 3) caused an increase in the activity of the anti-oxidant enzyme catalase. Overall, treatment with galantamine was able to prevent the brain damage, increase the survival of neurons, reduce astrocytic reaction and increase the activity of the anti-oxidant enzyme catalase in rats submitted to neonatal hypoxia ischemia.

Glial-associated changes in the cerebral cortex after collagenase-induced intracerebral hemorrhage in the rat striatum.

Striatum and the cerebral cortex are regions susceptible to secondary injury after intracerebral hemorrhage (ICH) and glial cells in tissue adjacent to the hematoma may modulate cellular vulnerability after brain damage. Nonetheless, while the glial- associated changes occurring in the cerebral cortex after ICH may be important in maximizing brain recovery, they are not fully understood. The aim of this study was to evaluate the temporal profile of glial-associated changes in the cerebral cortex after ICH. First, the motor consequences of ICH and its relation to the lesion volume were analyzed. Secondly, glial cell proportion (GFAP+ and S100B+ astrocytes, CD11+ microglia) in the ipsilesional sensorimotor cortex and striatum, using flow cytometry were evaluated. ELISA was used to measure GFAP and S100B content in these structures as well as S100B levels in serum and cerebral spinal fluid. Main results revealed that ICH induced a delayed increase in GFAP+ cells in the sensorimotor cortex, as compared to the striatum, although the pattern of GFAP expression was similar in both structures. Interestingly, the time-curve patterns of both S100B and CD11+ microglial cells differed between the cortex and striatum. Altogether, these results suggest a different dynamics of glial-associated changes in the cerebral cortex, suggesting it is a vulnerable structure and undergoes an independent secondary process of reactive glial plasticity following intracerebral hemorrhage.

Homocysteine as a peripheral biomarker in bipolar disorder: A meta-analysis.

BACKGROUND: Bipolar disorder (BD) is a psychiatric disorder with an uncertain aetiology. Recently, special attention has been given to homocysteine (Hcy), as it has been suggested that alterations in 1-carbon metabolism might be implicated in diverse psychiatric disorders. However, there is uncertainty regarding possible alterations in peripheral Hcy levels in BD. METHODS: This study comprises a meta-analysis comparing serum and plasma Hcy levels in persons with BD and healthy controls. We conducted a systematic search for all eligible English and non-English peer-reviewed articles. RESULTS: Nine cross-sectional studies were included in the meta-analyses, providing data on 1547 participants. Random-effects meta-analysis showed that serum and plasma levels of Hcy were increased in subjects with BD in either mania or euthymia when compared to healthy controls, with a large effect size in the mania group (g=0.98, 95% CI: 0.8-1.17, P<0.001, n=495) and a small effect in the euthymia group (g=0.3, 95% CI: 0.11-0.48, P=0.002, n=1052). CONCLUSIONS: Our meta-analysis provides evidence that Hcy levels are elevated in persons with BD during mania and euthymia. Peripheral Hcy could be considered as a potential biomarker in BD, both of trait (since it is increased in euthymia), and also of state (since its increase is more accentuated in mania). Longitudinal studies are needed to clarify the relationship between bipolar disorder and Hcy, as well as the usefulness of peripheral Hcy as both a trait and state biomarker in BD.

Ingesta insuficiente de vitamina D en población infantil española; condicionantes del problema y bases para su mejora / Insufficient intake of vitamin D in Spanish schoolchildren; determinants of the problem and basis for its improvement

Introducción: Pese a su importancia nutricional y sanitaria, diversos estudios han señalado la existencia de deficiencias en vitamina D en un elevado porcentaje de niños y han alertado sobre una problemática que había sido olvidada en poblaciones soleadas, como España. Objetivos: Valorar la adecuación de la ingesta de vitamina D y conocer las fuentes alimentarias de la vitamina en una muestra representativa de niños españoles. Métodos: Se ha estudiado un colectivo de 903 niños de 7 a 11 años, de diez provincias españolas, seleccionados para ser una muestra representativa de la población española de dicha edad. El estudio dietético se realizó utilizando un registro del consumo de alimentos durante 3 días, incluyendo un domingo, posteriormente la ingesta de vitamina D se comparó con las Ingestas Recomendadas (IR) y la ingesta energética con el gasto estimado. Los datos antropométricos registrados fueron peso, talla, e índice de masa corporal (IMC). Resultados y discusión: La ingesta de vitamina D en los niños estudiados (2,49 ± 0,64 ug/día) supuso un 49,7% de las IR, observándose la existencia de un 99,9% de niños con ingestas menores de las recomendadas y un 78,7 con ingestas < 67% de las IR. La ingesta es más baja en población femenina, niños de menor edad y en los que presentan obesidad. Al analizar la procedencia alimentaria de la vitamina D ingerida, se constata que la mayor parte procede de huevos (28,12%), cereales (24,23%), pescados (20,06%) y lácteos (14,42%). Conclusión: La ingesta de vitamina D es insuficiente en población infantil española de 7 a 11 años, teniendo en cuenta que el consumo de los alimentos, que son la principal fuente de la vitamina (pescado, huevo, cereales, lácteos) es, en muchos casos, menor del aconsejado, aproximar la alimentación al ideal teórico puede ayudar a conseguir aportes más adecuados de la vitamina (AU)

Introduction: Different studies have observed deficiencies in vitamin D in a high percentage of schoolchildren, highlighting the importance of this problem in sunny populations, such as Spain, where this situation is frequently underestimated. Aim: To assess the adequacy of vitamin D intake and to find out the food sources of the vitamin in a representative sample of Spanish schoolchildren. Methods: A sample of 903 children (7 to 11 years) was studied. Ten Spanish cities were selected to be a representative sample of the Spanish schoolchildren population. Dietetic study was carried out using a three-day food record, including a Sunday. Vitamin D was compared to that recommended (RI) and energy intake was compared with energy expenditure estimated by measuring physical activity level. Weight and height were recorded and body mass index (BMI) was calculated. Results and discussion: Vitamin D intake (2.49±0.64 [ig/day) allowed cover only 49.7% of the RI of the children. It was below of 100% of RI in 99.9% of the children, and in 78.7% it was below of 67% of RI. The vitamin intake was lower in girls, those younger than 7 years and in children with obesity than in boys, those older than 7 years and in children with normal weight. The main sources of the vitamin were eggs (28.12%), cereals (24.23%), fish (20.06%) and milk (14.42%). Conclusion: Vitamin D intake is inadequate in Spanish schoolchildren between 7 and 11 years. Taking into account that the consumption of foods which are the main source of vitamin D (fish, eggs, cereals, dairy products) is often lower than the recommended, approximating the diet to the theoretical ideal could help to improve the contribution of the vitamin (AU)

Evaluación mediante navegación intraoperatoria de la laxitud del ligamento cruzado anterior en su reconstrucción anatómica monofascicular / Evaluation of intraoperative anterior cruciate ligament laxity using a navigation system in the anatomical single bundle reconstruction

Objetivo. La técnica de reconstrucción anatómica del ligamento cruzado anterior (LCA) persigue, reproduciendo la orientación nativa de sus fibras, alcanzar una mejor estabilidad rotacional en la rodilla. El objetivo principal del presente trabajo es la evaluación cuantitativa intraoperatoria, mediante el uso del sistema de navegación de Orthopilot®, de la laxitud anteroposterior y rotacional de la rodilla antes y después de una ligamentoplastia anatómica. Material y método. Descripción de la técnica de navegación y estudio transversal sobre una cohorte de 20 pacientes intervenidos en nuestro centro por rotura primaria crónica del LCA desde enero de 2010 hasta mayo de 2011. Con la ayuda del navegador se definió la posición exacta de los túneles en base a referencias anatómicas intraarticulares y se realizaron pruebas de estabilidad, tanto en el plano sagital como en el axial. Resultados. Nuestra técnica de reconstrucción anatómica del LCA situó el túnel tibial a una distancia media de 16,8±4,92 mm del ligamento cruzado posterior y a un 44,1%±4,35% de la anchura total del platillo tibial. La distancia media del centro del túnel femoral a la cortical posterior del cóndilo lateral fue de 7,89±2,78 mm. Intraoperatoriamente y antes de la reconstrucción, los valores medios (±DE) de traslación anteroposterior, rotación interna y rotación externa de la tibia a 30° fueron de 15,5mm (±5,11); 19° (±3,62) y 19,65° (±3,26) respectivamente. Tras la reconstrucción dichos valores disminuyeron a 5,6mm (±1,72); 12,17° (±3,76) y 16,9° (±4,42). Conclusiones. El empleo de sistemas de navegación como apoyo al cirujano permite sistematizar la posición de los túneles óseos y estandarizar el procedimiento en relación a la reconstrucción deseada. La reconstrucción del LCA según la técnica descrita, mejora la estabilidad anteroposterior y rotacional monoplanar respecto al estado preoperatorio pudiendo restablecer los valores de laxitud a los considerados como fisiológicos acorde al conocimiento científico actual (AU)

Purpose. The anatomical anterior cruciate ligament (ACL) reconstruction attempts to, by reproducing the natural orientation of its fibres, achieve a better rotational stability of the knee. The aim of this paper is to quantify the anteroposterior and rotational laxity of the knee before and after an anatomic ligamentoplasty using the Orthopilot® navigation system as a supporting tool. Matherial and method. We describe the distinctive steps of Orthopilot® navigation as well as conducting a retrospective cross-sectional study on a cohort of 20 patients operated in our hospital for chronic primary ACL rupture from january 2010 to may 2011. The precise location of the tunnels was defined with the help of the navigator and the intra-articular landmarks and stability tests were performed in both the sagittal and axial planes. Results. In our technique for anatomical ACL reconstruction placed the tibial tunnel at a mean distance of 16.8±4.92mm from the posterior cruciate ligament in a position that represented 44.1%±4.35 of the total width of the tibial plateau. The average distance from the centre of the femoral tunnel to the posterior cortex of the lateral condyle was 7.89±2.78mm. Intra-operatively and before ACL reconstruction, the mean (±SD) anteroposterior movement, internal rotation and external rotation of the tibia at 30° position were 15.5mm (±5.11), 19° (±3.62) and 19.65° (±3.26), respectively. After reconstruction these values decreased to 5.6mm (±1.72°), 12.17° (±3.76) and 16.9° (±4.42), respectively. Conclusions. The use of navigation systems supporting the surgery allows the systematic positioning of bone tunnels and standardises the procedures for the desired reconstruction. ACL reconstruction using the technique described, improves the anteroposterior and rotational stability compared to preoperative status, to a stability state that could be considered physiological according to current scientific knowledge (AU)

[Insufficient intake of vitamin D in spanish schoolchildren: determinants of the problem and basis for its improvement]. / Ingesta insuficiente de vitamina D en población infantil española: condicionantes del problema y bases para su mejora.

INTRODUCTION: Different studies have observed deficiencies in vitamin D in a high percentage of schoolchildren, highlighting the importance of this problem in sunny populations, such as Spain, where this situation is frequently underestimated. AIM: To assess the adequacy of vitamin D intake and to find out the food sources of the vitamin in a representative sample of Spanish schoolchildren. METHODS: A sample of 903 children (7 to 11 years) was studied. Ten Spanish cities were selected to be a representative sample of the Spanish schoolchildren population. Dietetic study was carried out using a three-day food record, including a Sunday. Vitamin D was compared to that recommended (RI) and energy intake was compared with energy expenditure estimated by measuring physical activity level. Weight and height were recorded and body mass index (BMI) was calculated. RESULTS AND DISCUSSION: Vitamin D intake (2.49 ± 0.64 [iµ/day) allowed cover only 49.7% of the RI of the children. It was below of 100% of RI in 99.9% of the children, and in 78.7% it was below of 67% of RI. The vitamin intake was lower in girls, those younger than 7 years and in children with obesity than in boys, those older than 7 years and in children with normal weight. The main sources of the vitamin were eggs (28.12%), cereals (24.23%), fish (20.06%) and milk (14.42%). CONCLUSION: Vitamin D intake is inadequate in Spanish schoolchildren between 7 and 11 years. Taking into account that the consumption of foods which are the main source of vitamin D (fish, eggs, cereals, dairy products) is often lower than the recommended, approximating the diet to the theoretical ideal could help to improve the contribution of the vitamin.

[Evaluation of intraoperative anterior cruciate ligament laxity using a navigation system in the anatomical single bundle reconstruction]. / Evaluación mediante navegación intraoperatoria de la laxitud del ligamento cruzado anterior en su reconstrucción anatómica monofascicular.

PURPOSE: The anatomical anterior cruciate ligament (ACL) reconstruction attempts to, by reproducing the natural orientation of its fibres, achieve a better rotational stability of the knee. The aim of this paper is to quantify the anteroposterior and rotational laxity of the knee before and after an anatomic ligamentoplasty using the Orthopilot(®) navigation system as a supporting tool. MATHERIAL AND METHOD: We describe the distinctive steps of Orthopilot(®) navigation as well as conducting a retrospective cross-sectional study on a cohort of 20 patients operated in our hospital for chronic primary ACL rupture from january 2010 to may 2011. The precise location of the tunnels was defined with the help of the navigator and the intra-articular landmarks and stability tests were performed in both the sagittal and axial planes. RESULTS: In our technique for anatomical ACL reconstruction placed the tibial tunnel at a mean distance of 16.8±4.92 mm from the posterior cruciate ligament in a position that represented 44.1%±4.35 of the total width of the tibial plateau. The average distance from the centre of the femoral tunnel to the posterior cortex of the lateral condyle was 7.89±2.78 mm. Intra-operatively and before ACL reconstruction, the mean (±SD) anteroposterior movement, internal rotation and external rotation of the tibia at 30° position were 15.5 mm (±5.11), 19° (±3.62) and 19.65° (±3.26), respectively. After reconstruction these values decreased to 5.6 mm (±1.72°), 12.17° (±3.76) and 16.9° (±4.42), respectively. CONCLUSIONS: The use of navigation systems supporting the surgery allows the systematic positioning of bone tunnels and standardises the procedures for the desired reconstruction. ACL reconstruction using the technique described, improves the anteroposterior and rotational stability compared to preoperative status, to a stability state that could be considered physiological according to current scientific knowledge.

Involvement of glutaredoxin-1 and thioredoxin-1 in beta-amyloid toxicity and Alzheimer's disease.

Strong evidence indicates oxidative stress in the pathogenesis of Alzheimer's disease (AD). Amyloid beta (Abeta) has been implicated in both oxidative stress mechanisms and in neuronal apoptosis. Glutaredoxin-1 (GRX1) and thioredoxin-1 (TRX1) are antioxidants that can inhibit apoptosis signal-regulating kinase (ASK1). We examined levels of GRX1 and TRX1 in AD brain as well as their effects on Abeta neurotoxicity. We show an increase in GRX1 and a decrease in neuronal TRX1 in AD brains. Using SH-SY5Y cells, we demonstrate that Abeta causes an oxidation of both GRX1 and TRX1, and nuclear export of Daxx, a protein downstream of ASK1. Abeta toxicity was inhibited by insulin-like growth factor-I (IGF-I) and by overexpressing GRX1 or TRX1. Thus, Abeta neurotoxicity might be mediated by oxidation of GRX1 or TRX1 and subsequent activation of the ASK1 cascade. Deregulation of GRX1 and TRX1 antioxidant systems could be important events in AD pathogenesis.

Sptrx-2, a fusion protein composed of one thioredoxin and three tandemly repeated NDP-kinase domains is expressed in human testis germ cells.

BACKGROUND: Thioredoxins (Trx) are small redox proteins that function as general protein disulphide reductases and regulate several cellular processes such as transcription factor DNA binding activity, apoptosis and DNA synthesis. In mammalian organisms, thioredoxins are generally ubiquitously expressed in all tissues, with the exception of Sptrx-1 which is specifically expressed in sperm cells. RESULTS: We report here the identification and characterization of a novel member of the thioredoxin family, the second with a tissue-specific distribution in human sperm, termed Sptrx-2. The Sptrx-2 ORF (open reading frame) encodes for a protein of 588 amino acids with two different domains: an N-terminal thioredoxin domain encompassing the first 105 residues and a C-terminal domain composed of three repeats of a NDP kinase domain. The Sptrx-2 gene spans about 51 kb organized in 17 exons and maps at locus 7p13-14. Sptrx-2 mRNA is exclusively expressed in human testis, mainly in primary spermatocytes, while Sptrx-2 protein expression is detected from the pachytene spermatocytes stage onwards, peaking at round spermatids stage. Recombinant full-length Sptrx-2 expressed in bacteria displayed neither thioredoxin nor NDP kinase enzymatic activity. CONCLUSIONS: The sperm specific expression of Sptrx-2, together with its chromosomal assignment to a position reported as a potential locus for flagellar anomalies and male infertility phenotypes such as primary ciliary dyskinesia, suggests that it might be a novel component of the human sperm axonemal organization.

A genome-wide survey of human thioredoxin and glutaredoxin family pseudogenes.

The thioredoxin/glutaredoxin family consists of small heat-stable proteins that have a highly conserved CXXC active site and that participate in the regulation of many redox reactions. We have searched the human genome sequence to find putative pseudogenes (non-functional copies of protein-coding genes) for all known members of this family. This survey has resulted in the identification of seven processed pseudogenes for human Trx1 and two more for human Grx1. No evidence for the presence of processed pseudogenes has been found for the remaining members of this family. In addition, we have been unable to detect any non-processed pseudogenes derived from any member of the family in the human genome. The seven thioredoxin pseudogenes can be divided into two groups: Trx1-psi2, -psi3, -psi4, -psi5 and -psi6 arose from the functional ancestor, whereas Trx1-psi1 and -psi7 originated from Trx1-psi2 and -psi6, respectively. In all cases, the pseudogenes originated after the human/rodent radiation as shown by phylogenetic analysis. This is also the case for Grx1-psi1 and Grx1-psi2, which are placed between rodent and human sequences in the phylogenetic tree. Our study provides a molecular record of the recent evolution of these two genes in the hominid lineage.

Characterization of Sptrx, a novel member of the thioredoxin family specifically expressed in human spermatozoa.

Thioredoxins (Trx) are small ubiquitous proteins that participate in different cellular processes via redox-mediated reactions. We report here the identification and characterization of a novel member of the thioredoxin family in humans, named Sptrx (sperm-specific trx), the first with a tissue-specific distribution, located exclusively in spermatozoa. Sptrx open reading frame encodes for a protein of 486 amino acids composed of two clear domains: an N-terminal domain consisting of 23 highly conserved repetitions of a 15-residue motif and a C-terminal domain typical of thioredoxins. Northern analysis and in situ hybridization shows that Sptrx mRNA is only expressed in human testis, specifically in round and elongating spermatids. Immunostaining of human testis sections identified Sptrx protein in spermatids, while immunofluorescence and immunogold electron microscopy analysis demonstrated Sptrx localization in the cytoplasmic droplet of ejaculated sperm. Sptrx appears to have a multimeric structure in native conditions and is able to reduce insulin disulfide bonds in the presence of NADPH and thioredoxin reductase. During mammalian spermiogenesis in testis seminiferous tubules and later maturation in epididymis, extensive reorganization of disulfide bonds is required to stabilize cytoskeletal sperm structures. However, the molecular mechanisms that control these processes are not known. The identification of Sptrx with an expression pattern restricted to the postmeiotic phase of spermatogenesis, when the sperm tail is organized, suggests that Sptrx might be an important factor in regulating critical steps of human spermiogenesis.

Mitochondria of Saccharomyces cerevisiae contain one-conserved cysteine type peroxiredoxin with thioredoxin peroxidase activity.

Peroxiredoxins are ubiquitously expressed proteins that reduce hydroperoxides using disulfur-reducing compounds as electron donors. Peroxiredoxins (Prxs) have been classified in two groups dependent on the presence of either one (1-Cys Prx) or two (2-Cys Prx) conserved cysteine residues. Moreover, 2-Cys Prxs, also named thioredoxin peroxidases, have peroxide reductase activity with the use of thioredoxin as biological electron donor. However, the biological reducing agent for the 1-Cys Prx has not yet been identified. We report here the characterization of a 1-Cys Prx from yeast Saccharomyces cerevisiae that we have named Prx1p. Prx1p is located in mitochondria, and it is overexpressed when cells use the respiratory pathway, as well as in response to oxidative stress conditions. We show also that Prx1p has peroxide reductase activity in vitro using the yeast mitochondrial thioredoxin system as electron donor. In addition, a mutated form of Prx1p containing the absolutely conserved cysteine as the only cysteine residue also shows thioredoxin-dependent peroxide reductase activity. This is the first example of 1-Cys Prx that has thioredoxin peroxidase activity. Finally, exposure of null Prx1p mutant cells to oxidant conditions reveals an important role of the mitochondrial 1-Cys Prx in protection against oxidative stress.