Neuroinflammation: An Integrating Overview of Reactive-Neuroimmune Cell Interactions in Health and Disease.

The concept of central nervous system (CNS) inflammation has evolved over the last decades. Neuroinflammation is the response of reactive CNS components to altered homeostasis, regardless of the cause to be endogenous or exogenous. Neurological diseases, whether traumatic, neoplastic, ischemic, metabolic, toxic, infectious, autoimmune, developmental, or degenerative, involve direct and indirect immune-related neuroinflammation. Brain infiltrates of the innate and adaptive immune system cells appear in response to an infective or otherwise noxious agent and produce inflammatory mediators. Mediators of inflammation include local and recruited cells and signals. Processes derived from extrinsic and intrinsic CNS diseases also elicit the CNS inflammatory response. A deeper understanding of immune-related inflammation in health and disease is necessary to find potential therapeutic targets for preventing or reducing CNS damage. This review is aimed at discussing the innate and adaptive immune system functions and their roles in regulating brain cell responses in disease and homeostasis maintenance.

Prevalence and factors related to orthostatic syndromes in recently diagnosed, drug-naïve patients with Parkinson disease.

PURPOSE: The aim of this study was to explore the prevalence of and factors related to orthostatic syndromes in recently diagnosed drug-naïve patients with Parkinson disease (PD). METHODS: This was a cross-sectional study that included 217 drug-naïve patients with PD and 108 sex- and age-matched non-parkinsonian controls from the Parkinson's Progression Markers Initiative (PPMI) prospective cohort study who were devoid of diabetes, alcoholism, polyneuropathy, amyloidosis, and hypotension-inducing drugs. Orthostatic symptoms were evaluated using the Scales for Outcomes in PD-Autonomic Dysfunction (SCOPA-AUT). Ioflupane-I123 single-photon emission computerized tomography was used to evaluate striatal dopamine active transporter (DaT) levels. Blood pressure was assessed both in the supine position and 1-3 min after the switch to a standing position. Orthostatic hypotension (OH) was defined by international consensus, and orthostatic intolerance (OI) was defined as the presence of orthostatic symptoms in the absence of OH. RESULTS: Compared with non-parkinsonian controls, patients with PD experienced a mild fall in systolic blood pressure upon standing (p = 0.082). The prevalence of OH was 11.1% in PD patients and 5.6% in controls (p = 0.109). The prevalence of OI was higher in patients with PD than in controls (31.3 vs. 13.3%; p = 0.003). Logistic regression revealed that OH and OI were related to a lower striatal DaT level and higher SCOPA-AUT gastrointestinal score. CONCLUSIONS: Orthostatic syndromes were common in the recently diagnosed drug-naïve patients with PD enrolled in the study, but only the prevalence of OI was higher in PD patients than in the non-parkinsonian controls. Unlike motor or functional disability indicators, markers of dopaminergic striatal deficit and gastrointestinal dysfunction were associated with OH and OI.

Long-Term Effects of Hypoxia-Reoxygenation on Thioredoxins in Rat Central Nervous System.

BACKGROUND: Oxidative stress induced by the oxidative pathway dysregulation following ischemia/ reperfusion has been proposed as an important cause of neuronal death and brain damage. The proteins of the thioredoxin (Trx) family are crucial mediators of protein function regulating the intracellular hydrogen peroxide levels and redox-sensitive post-translational protein changes. AIM: To analyze the expression and distribution of fourteen members of the Trx family, potentially essential for the regeneration upon long-term brain damage, in a perinatal hypoxia-ischemia rat model induced by common carotid artery ligation. METHODS: The right common carotid artery (CCA) was exposed by an incision on the right side of the neck, isolated from nerve and vein, and permanently ligated. Sham-surgery rats underwent right CCA surgical exposure but no ligation. Euthanasia was administered to all rats at 30, 60, and 90 days of age. Protein expression and distribution of fourteen members of the Trx family and related proteins (Grx1, Grx2, Grx3, Grx5, Prx1, Prx2, Prx3, Prx4, Prx5, Prx6, Trx1, Trx2, TrxR1, TrxR2) was examined in the most hypoxia susceptible rat brain areas, namely, cerebellum, corpus striatum, and the hippocampus. RESULTS: The thioredoxin proteins displayed a complex, cell-type, and tissue-specific expression pattern following ischemia/reperfusion. Even 60 days after ischemia/reperfusion, Western blot analysis showed a persistent expression of Trx1 and Grx2 in several brain areas. CONCLUSION: The Trx family of proteins might contribute to long-term survival and recovery supporting their therapeutic use to curtail ischemic brain oxidative damage following an ischemia/reperfusion insult. Characterization of ischemia/reperfusion oxidative brain damage and analysis of the involved mechanisms are required to understand the underneath processes triggered by ischemia/reperfusion and to what extent and in what way thioredoxins contribute to recovery from brain hypoxic stress.

A Pilot Cross-Sectional Study to Investigate the Biomarker Potential of Phosphorylated Neurofilament-H and Immune Mediators of Disability in Patients With 5 Year Relapsing-Remitting Multiple Sclerosis.

Objective: To test the feasibility of conducting a full-scale project evaluating the potential value of the phosphorylated neurofilament H (pNF-H) and several cytokines as disability markers in relapsing-remitting multiple sclerosis (RRMS). Methods: Twenty-four patients with 5-year RRMS evolution and eleven healthy control subjects entered the study. None of the participants had an inflammatory systemic or metabolic disease. Disability progression was evaluated using the Expanded Disability Status Scale. Serum level of pNF-H, the anti-inflammatory cytokine transforming growth factor-ß 1 (TGF-ß1), and the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-17A (IL-17A), monocyte chemotactic protein-1 (MCP-1), and soluble intercellular cell-adhesion molecule 1 (sICAM-1) were quantified using enzyme-linked immunosorbent assay (ELISA). Results: The patients had higher serum level of TGF-ß1, IL-6, sICAM-1, and pNF-H. Based on these findings, a sample of at least 49 controls and 89 recent-onset RRMS patients is required to find an at least 1-point between-group difference in pNF-H with a power of 80% and an α error = 0.05. The progression of the disease was correlated with the level of pNF-H (Spearman rho = 0.624, p = 0.006), but not with the cytokines'. Conclusions: The serum level of pNF-H, EDSS score-correlated, might stand for a potential biomarker of disability in RRMS reflecting progressive axonal damage and cumulative neurological deterioration. The novelty of these results warrants conducting a larger confirmatory trial.

Neuroprotective Role of Hypothermia in Hypoxic-ischemic Brain Injury: Combined Therapies using Estrogen.

Hypoxic-ischemic brain injury is a complex network of factors, which is mainly characterized by a decrease in levels of oxygen concentration and blood flow, which lead to an inefficient supply of nutrients to the brain. Hypoxic-ischemic brain injury can be found in perinatal asphyxia and ischemic-stroke, which represent one of the main causes of mortality and morbidity in children and adults worldwide. Therefore, knowledge of underlying mechanisms triggering these insults may help establish neuroprotective treatments. Selective Estrogen Receptor Modulators and Selective Tissue Estrogenic Activity Regulators exert several neuroprotective effects, including a decrease of reactive oxygen species, maintenance of cell viability, mitochondrial survival, among others. However, these strategies represent a traditional approach of targeting a single factor of pathology without satisfactory results. Hence, combined therapies, such as the administration of therapeutic hypothermia with a complementary neuroprotective agent, constitute a promising alternative. In this sense, the present review summarizes the underlying mechanisms of hypoxic-ischemic brain injury and compiles several neuroprotective strategies, including Selective Estrogen Receptor Modulators and Selective Tissue Estrogenic Activity Regulators, which represent putative agents for combined therapies with therapeutic hypothermia.

Estradiol Activates PI3K/Akt/GSK3 Pathway Under Chronic Neurodegenerative Conditions Triggered by Perinatal Asphyxia.

Perinatal asphyxia (PA) remains as one of the most important causes of short-term mortality, psychiatric and neurological disorders in children, without an effective treatment. In previous studies we have observed that the expression of different neurodegenerative markers increases in CA1 hippocampal area of 4-months-old male rats born by cesarean section and exposed for 19 min to PA. We have also shown that a late treatment with 17ß estradiol (daily dose of 250 µg/kg for 3 days) was able to revert the brain alterations observed in those animals. Based on these previous results, the main aim of the present study was to explore the mechanism by which the estrogenic treatment is involved in the reversion of the chronic neurodegenerative conditions induced by PA. We demonstrated that estradiol treatment of adult PA exposed animals induced an increase in estrogen receptor (ER) α and insulin-like growth factor receptor (IGF-1R) protein levels, an activation of the phosphatidylinositol 3-kinase/Akt/glycogen synthase kinase 3 beta/ß-catenin signaling pathway and an increase in Bcl-2/Bax ratio in the hippocampus in comparison to PA exposed animals treated with vehicle. Taking together, our data suggest that the interaction between ERα and IGF-IR, with the subsequent downstream activation, underlies the beneficial effects of estradiol observed in late treatment of PA.

Immune-Mediated Inflammation Promotes Subclinical Atherosclerosis in Recent-Onset Psoriatic Arthritis Patients without Conventional Cardiovascular Risk Factors.

Studies on the inflammatory burden in recent-onset psoriatic arthritis (PsA) patients without conventional cardiovascular risk factors (CVRFs) are not available. This preliminary study focuses on cardiovascular risk in cutaneous psoriasis (CPs) and recent-onset PsA patients. Blood biochemistry (glucose, cholesterol, uric acid, lipid profile and apolipoprotein B) was analyzed using standard kits. Proatherogenic inflammation markers, C-reactive protein (CRP) and interleukin-6 (IL-6), and endothelial activators monocyte chemoattractant protein-1 (MCP-1) and soluble intercellular adhesion molecule-1 (sICAM-1), were determined by enzyme-linked immunosorbent assay. Ultrasound images allowed measuring carotid intima-media thickness (cIMT). Our study first shows an increase in cIMT, and in serum levels of sICAM-1 and CRP in recent-onset PsA patients not presenting conventional CVRFs over the non-medicated time-period, from disease diagnosis to the beginning of pharmacological treatment, compared with healthy subjects. The outcome highlights the importance of monitoring serum level of sICAM1, CRP, and cIMT, and the value of primary prevention in psoriatic patients even with no history of cardiovascular events.

Expresión y distribución de las Tioredoxinas durante asfixia perinatal. Su rol en la regulación del equilibrio redox / EXPRESSION AND DISTRIBUTION OF THIOREDOXINS IN PERINATAL ASPHYXIA

This article deals with the expression and distribution of Thioredoxins during perinatal asphyxia, and its roll in the regulation of the redox system. Disorders in the gaseous interchange through the placenta and the fetal lungs, can lead to what is known as the perinatal asphyxia (PA). The PA can involve all the organ systems, but has more severe effects on the Central Nervous System (CNS), producing damage as much as in the short term as in the long term. The disturbance recognized as oxidative stress, is considered as a disorder in the normal process of redox regulation. Thioredoxins are a group of proteins involucrated in the regulation of the cellular redox state. The aim of this report was to analyze the changes of the expression of Thioredoxins at a long term sustained on the hypothesis that the disorder at a short term induced by the perinatal asphyxia leds to substantial changes in a large term in the CNS.

Neuronal Damage Induced by Perinatal Asphyxia Is Attenuated by Postinjury Glutaredoxin-2 Administration.

The general disruption of redox signaling following an ischemia-reperfusion episode has been proposed as a crucial component in neuronal death and consequently brain damage. Thioredoxin (Trx) family proteins control redox reactions and ensure protein regulation via specific, oxidative posttranslational modifications as part of cellular signaling processes. Trx proteins function in the manifestation, progression, and recovery following hypoxic/ischemic damage. Here, we analyzed the neuroprotective effects of postinjury, exogenous administration of Grx2 and Trx1 in a neonatal hypoxia/ischemia model. P7 Sprague-Dawley rats were subjected to right common carotid ligation or sham surgery, followed by an exposure to nitrogen. 1 h later, animals were injected i.p. with saline solution, 10 mg/kg recombinant Grx2 or Trx1, and euthanized 72 h postinjury. Results showed that Grx2 administration, and to some extent Trx1, attenuated part of the neuronal damage associated with a perinatal hypoxic/ischemic damage, such as glutamate excitotoxicity, axonal integrity, and astrogliosis. Moreover, these treatments also prevented some of the consequences of the induced neural injury, such as the delay of neurobehavioral development. To our knowledge, this is the first study demonstrating neuroprotective effects of recombinant Trx proteins on the outcome of neonatal hypoxia/ischemia, implying clinical potential as neuroprotective agents that might counteract neonatal hypoxia/ischemia injury.

Are astrocytes executive cells within the central nervous system? / ¿Son los astrocitos células ejecutivas dentro del Sistema Nervioso Central?

ABSTRACT Experimental evidence suggests that astrocytes play a crucial role in the physiology of the central nervous system (CNS) by modulating synaptic activity and plasticity. Based on what is currently known we postulate that astrocytes are fundamental, along with neurons, for the information processing that takes place within the CNS. On the other hand, experimental findings and human observations signal that some of the primary degenerative diseases of the CNS, like frontotemporal dementia, Parkinson’s disease, Alzheimer’s dementia, Huntington’s dementia, primary cerebellar ataxias and amyotrophic lateral sclerosis, all of which affect the human species exclusively, may be due to astroglial dysfunction. This hypothesis is supported by observations that demonstrated that the killing of neurons by non-neural cells plays a major role in the pathogenesis of those diseases, at both their onset and their progression. Furthermore, recent findings suggest that astrocytes might be involved in the pathogenesis of some psychiatric disorders as well.

RESUMEN Evidencias experimentales sugieren que los astrocitos desempeñan un rol crucial en la fisiología del sistema nervioso central (SNC) modulando la actividad y plasticidad sináptica. En base a lo actualmente conocido creemos que los astrocitos participan, en pie de igualdad con las neuronas, en los procesos de información del SNC. Además, observaciones experimentales y humanas encontraron que algunas de las enfermedades degenerativas primarias del SNC: la demencia fronto-temporal; las enfermedades de Parkinson, de Alzheimer, y de Huntington, las ataxias cerebelosas primarias y la esclerosis lateral amiotrófica, que afectan solo a los humanos, pueden deberse a astroglíopatía. Esta hipótesis se sustenta en hallazgos que demostraron que la muerte neuronal que en ellas ocurre es debida al compromiso de células no-neuronales que juegan rol principal en su iniciación y desarrollo. Más aún, observaciones recientes señalan que los astrocitos podrían estar implicados en la patogenia de algunas enfermedades psiquiátricas.

Early ß-Amyloid-induced Synaptic Dysfunction Is Counteracted by Estrogen in Organotypic Hippocampal Cultures.

In the present study we set up a model of slow progression of neuronal injury by exposing organotypic hippocampal cultures to a low concentration of Amyloid ß (25-35) peptide (Aß, 2 µM) to analyze the time-related effects of 17-ß estradiol (17ß-E2, 10 nM). Neuronal death occurs after 7 d and is prevented by addition of 17ß-E2 24 h prior to, together with or 48 h after exposure to Aß. This effect is mimicked by selective ERα agonist PPT (100 nM). Treatment with Aß leads to early and transient (16-72 h) increase of pre- and post-synaptic proteins synaptophysin and PSD95, followed by a decrease coincident with neuronal death (7d), all prevented by 17ß-E2. At 72 h of Aß exposure, synaptic activity is increased, as by higher levels of glutamate and increased loading and unloading of FM 1-43-labeled synaptic vesicles. All these effects are also prevented by 17ß-E2. These data point out beneficial effects of estrogen on early Aß-induced synaptic disruption.

Thioredoxin 1 and glutaredoxin 2 contribute to maintain the phenotype and integrity of neurons following perinatal asphyxia.

BACKGROUND: Thioredoxin (Trx) family proteins are crucial mediators of cell functions via regulation of the thiol redox state of various key proteins and the levels of the intracellular second messenger hydrogen peroxide. Their expression, localization and functions are altered in various pathologies. Here, we have analyzed the impact of Trx family proteins in neuronal development and recovery, following hypoxia/ischemia and reperfusion. METHODS: We have analyzed the regulation and potential functions of Trx family proteins during hypoxia/ischemia and reoxygenation of the developing brain in both an animal and a cellular model of perinatal asphyxia. We have analyzed the distribution of 14 Trx family and related proteins in the cerebellum, striatum, and hippocampus, three areas of the rat brain that are especially susceptible to hypoxia. Using SH-SY5Y cells subjected to hypoxia and reoxygenation, we have analyzed the functions of some redoxins suggested by the animal experiment. RESULTS AND CONCLUSIONS: We have described/discovered a complex, cell-type and tissue-specific expression pattern following the hypoxia/ischemia and reoxygenation. Particularly, Grx2 and Trx1 showed distinct changes during tissue recovery following hypoxia/ischemia and reoxygenation. Silencing of these proteins in SH-SY5Y cells subjected to hypoxia-reoxygenation confirmed that these proteins are required to maintain the normal neuronal phenotype. GENERAL SIGNIFICANCE: These findings demonstrate the significance of redox signaling in cellular pathways. Grx2 and Trx1 contribute significantly to neuronal integrity and could be clinically relevant in neuronal damage following perinatal asphyxia and other neuronal disorders.

Tibolone protects T98G cells from glucose deprivation.

The steroidal drug Tibolone is used for the treatment of climacteric symptoms and osteoporosis in post-menopausal women. Although Tibolone has been shown to exert neuroprotective actions after middle cerebral artery occlusion, its specific actions on glial cells have received very little attention. In the present study we have assessed whether Tibolone exerts protective actions in a human astrocyte cell model, the T98G cells, subjected to glucose deprivation. Our findings indicate that Tibolone decreases the effects of glucose deprivation on cell death, nuclear fragmentation, superoxide ion production, mitochondrial membrane potential, cytoplasmic calcium concentration and morphological parameters. These findings suggest that glial cells may participate in the neuroprotective actions of Tibolone in the brain.

Moderate and severe perinatal asphyxia induces differential effects on cocaine sensitization in adult rats.

Perinatal asphyxia (PA) increases the likelihood of suffering from dopamine-related disorders, such as ADHD and schizophrenia. Since dopaminergic transmission plays a major role in cocaine sensitization, the purpose of this study was to determine whether PA could be associated with altered behavioral sensitization to cocaine. To this end, adult rats born vaginally (CTL), by caesarean section (C+), or by C+ with 15 min (PA15, moderate PA) or 19 min (PA19, severe PA) of global anoxia were repeatedly administered with cocaine (i.p., 15 mg/kg) and then challenged with cocaine (i.p., 15 mg/kg) after a 5-day withdrawal period. In addition, c-Fos, FosB/ΔFosB, DAT, and TH expression were assessed in dorsal (CPu) and ventral (NAcc) striatum. Results indicated that PA15 rats exhibited an increased locomotor sensitization to cocaine, while PA19 rats displayed an abnormal acquisition of locomotor sensitization and did not express a sensitized response to cocaine. c-Fos expression in NAcc, but not in CPu, was associated with these alterations in cocaine sensitization. FosB/ΔFosB expression was increased in all groups and regions after repeated cocaine administration, although it reached lower expression levels in PA19 rats. In CTL, C+, and PA15, but not in PA19 rats, the expression of TH in NAcc was reduced in groups repeatedly treated with cocaine, independently of the challenge test. Furthermore, this reduction was more pronounced in PA15 rats. DAT expression remained unaltered in all groups and regions studied. These results suggest that moderate PA may increase the vulnerability to drug abuse and in particular to cocaine addiction.

Novel interactions of GRP78: UPR and estrogen responses in the brain.

Glucose-regulated protein 78 (GRP78; 78 kDa) belongs to a group of highly conserved heat shock proteins (Hsp) with important functions at the cellular level. The emerging interest for GRP78 relies on its different functions, both in normal and pathological circumstances. GRP78 regulates intracellular calcium, protein shaping, endoplasmic reticulum (ER) stress and cell survival by an immediate response to insults, and that its expression may also be regulated by estrogens. Although these roles are well explored, the mechanisms by which GRP78 induces these changes are not completely understood. In this review, we highlight various aspects related to the GRP78 functioning in cellular protection and repair in response to ER stress and unfolded protein response by the regulation of intracellular Ca(2+) and other mechanisms. In this respect, the novel interactions between GRP78 and estrogens, such as estradiol and others, are analyzed in the context of the central nervous system (CNS). We also discuss the importance of GRP78 and estrogens in brain diseases including ischemia, Alzheimer's and Huntington's disorders. Finally, the main protective mechanisms of GRP78 and estrogens during ER dysfunction in the brain are described, and the prospective roles of GRP78 in therapeutic processes.

Long-chain acyl-CoA synthetase 4 is regulated by phosphorylation.

Long chain acyl CoA synthetase 4 (Acsl4) is a key enzyme in steroidogenesis. It participates in steroid synthesis through of arachidonic acid release and Steroidogenic Acute Regulatory protein (StAR) induction. Acsl4 prefers arachidonic acid as substrate and acts probably as a homodimer. In steroidogenic cells, it has been demonstrated that Acsl4 is a high turnover protein located mainly in mitochondrial-associated membrane fraction (MAM) bound to other proteins and that it is newly synthesized by hormone stimulation. The synthesis of Acsl4 constitutes an early step in steroidogenesis. In the steroid synthesis process, activation of kinases plays a very important role. For this reason, the aim of this work was to study Acsl4 as a possible phosphoprotein and try to elucidate the role of its phosphorylation. We have determined for the first time that Acsl4 is a phosphoprotein whose phosphorylation is hormone-dependent. We also demonstrated that Acsl4 acts effectively as a dimer and that phosphorylation occurs after dimer formation. Studies in vitro demonstrated that Acsl4 is a substrate of both PKA and PKC and its phosphorylation by these kinases regulates its activity.

Effects of natural antioxidants in neurodegenerative disease.

Polyphenols are secondary metabolites with antioxidant properties and are abundant in the diet. Fruits, vegetables, herbs, and various drinks (tea, wine, and juices) are all sources of these molecules. Despite their abundance, investigations into the benefits of polyphenols in human health have only recently begun. Phenolic compounds have received increasing interest because of numerous epidemiological studies. These studies have suggested associations between the consumption of polyphenol-rich aliments and the prevention of chronic diseases, such as cancer, cardiovascular diseases, and neurodegenerative diseases. More specifically, in the last 10 years literature on the neuroprotective effects of a polyphenol-rich diet has grown considerably. It has been demonstrated, in various cell culture and animal models, that these metabolites are able to protect neuronal cells by attenuating oxidative stress and damage. However, it remains unclear as to how these compounds reach the brain, what concentrations are necessary, and what biologically active forms are needed to exert beneficial effects. Therefore, further research is needed to identify the molecular pathways and intracellular targets responsible for polyphenol's neuroprotective effects. The aim of this paper is to present various well-known dietary polyphenols and their mechanisms of neuroprotection with an emphasis on Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis.

An early treatment with 17-ß-estradiol is neuroprotective against the long-term effects of neonatal ionizing radiation exposure.

Ionizing radiations can induce oxidative stress on target tissues, acting mainly through reactive oxygen species (ROS). The aim of this work was to investigate if 17-ß-estradiol (ßE) was able to prevent hippocampal-related behavioral and biochemical changes induced by neonatal ionizing radiation exposure and to elucidate a potential neuroprotective mechanism. Male Wistar rats were irradiated with 5 Gy of X-rays between 24 and 48 h after birth. A subset of rats was subcutaneously administered with successive injections of ßE or 17-α-estradiol (αE), prior and after irradiation. Rats were subjected to different behavioral tasks to evaluate habituation and associative memory as well as anxiety levels. Hippocampal ROS levels and protein kinase C (PKC) activity were also assessed. Results show that although ßE was unable to prevent radiation-induced hippocampal PKC activity changes, most behavioral abnormalities were reversed. Moreover, hippocampal ROS levels in ßE-treated irradiated rats approached control values. In addition, αE administered to irradiated animals was effective in preventing radiation-induced alterations. In conclusion, ßE was able to counteract behavioral and biochemical changes induced in irradiated animals, probably acting through an antioxidant mechanism.

The actin filament network associated to Sertoli cell ectoplasmic specializations.

Junctional devices in Sertoli cells conform the blood-testis barrier and play a key role in maturation and differentiation of germ cells. The spacial distribution of ectoplasmic specializations of Sertoli cells was studied by beta-actin immunolabelling, using laser confocal and transmission electron microscopy. For confocal microscopy, beta-actin immunolabelling of ectoplasmic specializations was studied over the background of either prosaposin or glutaredoxin immunolabelling of the Sertoli cytoplasm. Labelling was found near the basal lamina, surrounding early spermatocytes (presumably in leptotene-zygotene) or at one of two levels in the seminiferous epithelium: (1) around deep infoldings of the Sertoli cell cytoplasm, in tubular stages before spermiation, and (2) in the superficial part of the seminiferous epithelium, in tubular stages after or during spermiation. For transmission electron microscopy, beta-actin immunolabelling of ectoplasmic specializations was also used. Ectoplasmic specializations were found at two different levels of the seminiferous epithelium. We also used freeze fracture to analyze the characteristics of tubulo-bulbar complexes, a known component of apical ectoplasmic specializations. Also, these different approaches allowed us to study the complex arrangement of the actin cytoskeleton of Sertoli cells branches, which surround germ cells in different stages of the spermatogenic cycle. Our results show a consistent labelling for beta-actin before, during and after the release of spermatozoa in the tubular lumen (spermiation) suggesting a significant role of the actin network in spermatic cell differentiation. In conclusion, significant interrelations among the beta-actin network, the junctional complexes of the blood-testis barrier and the ectoplasmic specializations were detected at different stages of the seminiferous cycle.

Paullinia cupana Mart. var. Sorbilis protects human dopaminergic neuroblastoma SH-SY5Y cell line against rotenone-induced cytotoxicity.

Paullinia cupana Mart. var. Sorbilis, commonly known as Guaraná, is a Brazilian plant frequently cited for its antioxidant properties and different pharmacological activities on the central nervous system. The potential beneficial uses of Guaraná in neurodegenerative disorders, such as in Parkinson's disease (PD), the pathogenesis of which is associated with mitochondrial dysfunction and oxidative stress, has not yet been assessed. Therefore, the main aim of the present study was to evaluate if an extract of commercial powdered seeds of Guaraná could protect human dopaminergic neuroblastoma SH-SY5Y cell line against rotenone-induced cytotoxicity. Two concentration of Guaraná dimethylsulfoxide extract (0.312 and 0.625 mg/mL) were added to SH-SY5Y cells treated with 300 nM rotenone for 48 h, and the cytoprotective effects were assessed by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, measuring lactate dehydrogenase (LDH) levels, and analyzing nuclear integrity with Hoechst33258 stain. Results showed that the addition of Guaraná extract significantly increased the cell viability of SH-SY5Y cells treated with rotenone, in a dose-dependent manner. On the other hand, LDH levels were significantly reduced by addition of 0.312 mg/mL of Guaraná, but unexpectedly, no changes were observed with the higher concentration. Moreover, chromatin condensation and nuclear fragmentation were significantly reduced by addition of any of both concentrations of the extract. The results obtained in this work could provide relevant information about the mechanisms underlying the degeneration of dopaminergic neurons in PD and precede in vivo experiments. Further studies are needed to investigate which active constituent is responsible for the cytoprotective effect produced by Paullinia cupana.