S100 is present in developing chicken neurons and Schwann cells and promotes motor neuron survival in vivo

Herpes simplex virus type 1 modifies the protein composition of extracellular vesicles to promote neurite outgrowth and neuroinfection

The highly prevalent herpes simplex virus type 1 (HSV-1) causes a range of diseases, including cold sores, blinding keratitis, and life-threatening encephalitis. HSV-1 initially replicates in epithelial cells, enters the peripheral nervous system via neurites, and establishes lifelong infection in the neuronal cell bodies. Neurites are highly dynamic structures that grow or retract in response to attractive or repulsive cues, respectively. Here, we show that infection with HSV-1, but not with a mutant virus lacking glycoprotein G (gG), reduced the repulsive effect of epithelial cells on neurite outgrowth and facilitated HSV-1 invasion of neurons. HSV-1 gG was required and sufficient to induce neurite outgrowth by modifying the protein composition of extracellular vesicles, increasing the amount of neurotrophic and neuroprotective proteins, including galectin-1. Antibodies directed against galectin-1 neutralized the capacity of extracellular vesicles released from HSV-1-infected cells to promote neurite outgrowth. Our study provides new insights into the neurotropism of HSV-1 and identifies a viral protein that modifies the protein composition of extracellular vesicles to stimulate neurite outgrowth and invasion of the nervous system.IMPORTANCEHerpes simplex virus type 1 (HSV-1) must infect neurites (or nerve endings) to establish a chronic infection in neurons. Neurites are highly dynamic structures that retract or grow in the presence of repulsive or attractive proteins. Some of these proteins are released by epithelial cells in extracellular vesicles and act upon interaction with their receptor present on neurites. We show here that HSV-1 infection of epithelial cells modulated their effect on neurites, increasing neurite growth. Mechanistically, HSV-1 glycoprotein G (gG) modifies the protein composition of extracellular vesicles released by epithelial cells, increasing the amount of attractive proteins that enhance neurite outgrowth and facilitate neuronal infection. These results could inform of therapeutic strategies to block HSV-1 induction of neurite outgrowth and, thereby, neuronal infection.

Longitudinal assessment of S100B serum levels and clinical factors in youth patients with mood disorders

Mood disorders have been discussed as being in relation to glial pathology. S100B is a calcium-binding protein, and a marker of glial dysfunctions. Although alterations in the S100B expression may play a role in various central nervous system diseases, there are no studies on the potential role of S100B in mood disorders in adolescents and young adults . In a prospective two-year follow-up study, peripheral levels of S100B were investigated in 79 adolescent/young adult patients (aged 14–24 years), diagnosed with mood disorders and compared with 31 healthy control subjects. A comprehensive clinical interview was conducted which focused on clinical symptoms and diagnosis change. The diagnosis was established and verified at each control visit. Serum S100B concentrations were determined. We detected: lower S100B levels in medicated patients, compared with those who were drug-free, and healthy controls; higher S100B levels in a depressed group with a family history of affective disorder; correlations between age and medication status; sex-dependent differences in S100B levels; and lack a of correlation between the severity of depressive or hypo/manic symptoms. The results of our study indicate that S100B might be a trait-dependent rather than a state-dependent marker. Due to the lack of such studies in the youth population, further research should be performed. A relatively small sample size, a lack of exact age-matched control group, a high drop-out rate.

Characterization of cell type-specific S100B expression in the mouse olfactory bulb

S100B is an EF-hand type Ca2+-binding protein of the S100 family, known to support neurogenesis and to promote the interactions between brain's nervous and immune systems. Here, we characterized the expression of S100B in the mouse olfactory bulb, a neurogenic niche comprising mature and adult-born neurons, astrocytes, oligodendrocytes and microglia. Besides astrocytes, for which S100B is a classical marker, S100B was also expressed in NG2 cells and, surprisingly, in APC-positive myelinating oligodendrocytes but not in mature/adult-born neurons or microglia. Various layers of the bulb differed substantially in the composition of S100B-positive cells, with the highest fraction of the APC-positive oligodendrocytes found in the granule cell layer. Across all layers, ∼50 % of NG2 cells were S100B-negative. Finally, our data revealed a strong correlation between the fraction of myelinating oligodendrocytes among the S100B-positive cells and the oligodendrocyte density in different brain areas, underscoring the importance of S100B for the establishment and maintenance of myelin sheaths.

High Serum Levels of Serum 100 Beta Protein, Neuron-specific Enolase, Tau, Active Caspase-3, M30 and M65 in Children with Autism Spectrum Disorders

Objective

The purpose of this study was therefore to investigate whether neuronal, axonal, and glial cell markers (Neuron-specific enolase [NSE], tau, serum 100 beta protein [S100B], respectively) and apoptosis markers (active caspase 3, M30, M65) and whether these parameters can be used as diagnostic biomarkers in autism spectrum disorders (ASD).

Methods

This study measured the serum S100B, NSE, tau, active caspase 3, M30, and M65 levels in 43 patients with ASD (aged 3−12 years) and in 41 age- and sex-matched healthy controls. ASD severity was rated using the Childhood Autism Rating Scale. The serum levels were determined in the biochemistry laboratory using the ELISA technique. The receiver operator characteristics curve method was employed to evaluate the accuracy of the parameters in diagnosing ASD.

Results

Serum S100B, tau, NSE, active caspase-3, M30, and M65 levels were significantly higher in the patient group than in the control group (p < 0.001, p = 0.002, p = 0.002, p = 0.005, p < 0.001, and p = 0.004, respectively). The cut-off value of S100B was 48.085 pg/ml (sensitivity: 74.4%, specificity: 80.5%, areas under the curve: 0.879, p < 0.001).

Conclusion

Apoptosis increased in children with ASD, and neuronal, axonal, and glial cell injury was observed. In addition, S100B may be an important diagnostic biomarker in patients with ASD. Apoptosis, and neuronal, axonal and astrocyte pathologies may play a significant role in the pathogenesis of ASD, and further studies are now required to confirm this.

Perinatal SSRI medications and offspring hippocampal plasticity: interaction with maternal stress and sex

There is growing use of selective serotonin reuptake inhibitor antidepressant (SSRI) medications during the perinatal period to treat maternal affective disorders. Perinatal SSRI exposure can have a long-term impact on offspring neuroplasticity and behavioral development that remains to be fully elucidated. This mini-review will summarize what is known about the effects of perinatal SSRIs on plasticity in the developing hippocampus, taking into account the role that maternal stress and depression may have. Emerging clinical findings and research in animal models will be discussed. In addition, sexually differentiated effects will be highlighted, as recent work shows that male offspring are often more sensitive to the effects of maternal stress, whereas female offspring can be more sensitive to perinatal SSRIs. Potential mechanisms behind these changes and aims for future research will also be discussed. Understanding the impact of perinatal SSRIs on neuroplasticity will provide better insight into the long-term effects of such medications on the health and well-being of both mother and child and may improve therapeutic approaches for maternal mood disorders during the perinatal period.

Palmitoylethanolamide Dampens Reactive Astrogliosis and Improves Neuronal Trophic Support in a Triple Transgenic Model of Alzheimer's Disease: In Vitro and In Vivo Evidence

Alzheimer's disease (AD) is a neurodegenerative disorder responsible for the majority of dementia cases in elderly people. It is widely accepted that the main hallmarks of AD are not only senile plaques and neurofibrillary tangles but also reactive astrogliosis, which often precedes detrimental deposits and neuronal atrophy. Such phenomenon facilitates the regeneration of neural networks; however, under some circumstances, like in AD, reactive astrogliosis is detrimental, depriving neurons of the homeostatic support, thus contributing to neuronal loss. We investigated the presence of reactive astrogliosis in 3×Tg-AD mice and the effects of palmitoylethanolamide (PEA), a well-documented anti-inflammatory molecule, by in vitro and in vivo studies. In vitro results revealed a basal reactive state in primary cortical 3×Tg-AD-derived astrocytes and the ability of PEA to counteract such phenomenon and improve viability of 3×Tg-AD-derived neurons. In vivo observations, performed using ultramicronized- (um-) PEA, a formulation endowed with best bioavailability, confirmed the efficacy of this compound. Moreover, the schedule of treatment, mimicking the clinic use (chronic daily administration), revealed its beneficial pharmacological properties in dampening reactive astrogliosis and promoting the glial neurosupportive function. Collectively, our results encourage further investigation on PEA effects, suggesting it as an alternative or adjunct treatment approach for innovative AD therapy.

Effects of electromagnetic field (PEMF) exposure at different frequency and duration on the peripheral nerve regeneration: in vitro and in vivo study

PURPOSE

The purpose was to clarify the influence of frequency and exposure time of pulsed electromagnetic fields (PEMF) on the peripheral nerve regeneration.

MATERIALS AND METHODS

Immortalized rat Schwann cells (iSCs) (1 × 10(2)/well) were exposed at four different conditions in 1 mT (50 Hz 1 h/d, 50 Hz 12 h/d, 150 Hz 1 h/d and 150 Hz 12h/d). Cell proliferation, mRNA expression of S100 and brain-derived neurotrophic factor (BDNF) were analyzed. Sprague-Dawley rats (200-250 g) were divided into six groups (n = 10 each): control, sham, 50 Hz 1 h/d, 50 Hz 12 h/d, 150 Hz 1 h/d and 150 Hz 12 Hr/d. Mental nerve was crush-injured and exposed at four different conditions in 1 mT (50 Hz 1 Hr/d, 50 Hz 12 Hr/d, 150 Hz 1 h/d and 150 Hz 12 h/d). Nerve regeneration was evaluated with functional test, histomorphometry and retrograde labeling of trigeminal ganglion.

RESULTS

iSCs proliferation with 50 Hz, 1 h/d was increased from fourth to seventh day; mRNA expression of S100 and BDNF was significantly increased at the same condition from first week to third week (p < .05 vs. control); difference score was increased at the second and third week, and gap score was increased at the third under 50 Hz 1 h PEMF compared with control while other conditions showed no statistical meaning. Axon counts and retrograde labeled neurons were significantly increased under PEMF of four different conditions compared with control. Although there was no statistical difference, 50 Hz, 1 h PEMF showed highest regeneration ability than other conditions.

CONCLUSION

PEMF enhanced peripheral nerve regeneration, and that it may be due to cell proliferation and increase in BDNF and S100 gene expression.

Developmental exposure to SSRIs, in addition to maternal stress, has long-term sex-dependent effects on hippocampal plasticity

RATIONALE

During pregnancy and postpartum period, 20 % of women are affected by depression, which is a growing health concern. Selective serotonin reuptake inhibitor (SSRI) medications are popular treatments for maternal depression; however, the effect of maternal depression and perinatal SSRI exposure on offspring's neural development needs further investigation.

OBJECTIVES

This study aims to determine the role of developmental fluoxetine exposure on hippocampal plasticity in the adult offspring.

METHODS

Sprague-Dawley rat offspring were exposed to fluoxetine beginning on postnatal day 1. Offspring were also exposed to prenatal maternal stress. Four groups of male and female offspring were used: (1) prenatal stress + fluoxetine, (2) prenatal stress + vehicle, (3) fluoxetine alone, and (4) vehicle alone. Hippocampi were analyzed for levels of cell proliferation, immature neurons, and new cell survival (3 weeks after 5-bromo-2-deoxyuridine injection) in the granule cell layer, as well as synaptophysin density in the CA3 region and granule cell layer. TPH staining was assessed in the dorsal raphe nucleus.

RESULTS

Developmental fluoxetine exposure to prenatally stressed offspring reversed the effect of prenatal stress or fluoxetine exposure alone on the number of immature neurons. Prenatal stress alone, regardless of developmental exposure to fluoxetine, markedly decreased hippocampal cell proliferation and tended to decrease new cell survival. Furthermore, in adult female offspring, developmental fluoxetine exposure greatly increased new cell survival and significantly decreased synaptophysin density in the granule cell layer.

CONCLUSIONS

There are long-term effects of developmental SSRI exposure on hippocampal plasticity that is differentially affected by expose to maternal adversity and offspring sex.

S100B as a marker for brain damage and blood-brain barrier disruption following exercise

BACKGROUND

S100B level in the blood has been used as a marker for brain damage and blood-brain barrier (BBB) disruption. Elevations of S100B levels after exercise have been observed, suggesting that the BBB may be compromised during exercise. However, an increase in S100B levels may be confounded by other variables.

OBJECTIVES

The primary objective of this review was to compile findings on the relationship between S100B and exercise in order to determine if this protein is a valid marker for BBB disruptions during exercise. The secondary objective was to consolidate known factors causing S100B increases that may give rise to inaccurate interpretations of S100B levels.

DATA SOURCES AND STUDY SELECTION

PubMed, Web of Science and ScienceDirect were searched for relevant studies up to January 2013, in which S100B measurements were taken after a bout of exercise. Animal studies were excluded. Variables of interest such as the type of activity, exercise intensities, duration, detection methods, presence and extent of head trauma were examined and compiled.

RESULTS

This review included 23 studies; 15 (65 %) reported S100B increases after exercise, and among these, ten reported S100B increases regardless of intervention, while five reported increases in only some trials but not others. Eight (35 %) studies reported no increases in S100B levels across all trials. Most baseline S100B levels fall below 0.16 μg/L, with an increase in S100B levels of less than 0.07 μg/L following exercise. Factors that are likely to affect S100B levels include exercise intensity, and duration, presence and extent of head trauma. Several other probable factors influencing S100B elevations are muscle breakdown, level of training and oxidative stress, but current findings are still weak and inconclusive.

CONCLUSIONS

Elevated S100B levels have been recorded following exercise and are mostly attributed to either an increase in BBB permeability or trauma to the head. However, even in the absence of head trauma, it appears that the BBB may be compromised following exercise, with the severity dependent on exercise intensity.

Receptor for advanced glycation end products (RAGE) and its ligands: focus on spinal cord injury

Spinal cord injury (SCI) results in neuronal and glial death and the loss of axons at the injury site. Inflammation after SCI leads to the inhibition of tissue regeneration and reduced neuronal survival. In addition, the loss of axons after SCI results in functional loss below the site of injury accompanied by neuronal cell body's damage. Consequently, reducing inflammation and promoting axonal regeneration after SCI is a worthy therapeutic goal. The receptor for advanced glycation end products (RAGE) is a transmembrane protein and receptor of the immunoglobulin superfamily. RAGE is implicated in inflammation and neurodegeneration. Several recent studies demonstrated an association between RAGE and central nervous system disorders through various mechanisms. However, the relationship between RAGE and SCI has not been shown. It is imperative to elucidate the association between RAGE and SCI, considering that RAGE relates to inflammation and axonal degeneration following SCI. Hence, the present review highlights recent research regarding RAGE as a compelling target for the treatment of SCI.

Nerve guidance conduits based on double-layered scaffolds of electrospun nanofibers for repairing the peripheral nervous system

Compared to the nerve guidance conduits (NGCs) constructed from a single layer of aligned nanofibers, bilayer NGCs with random and aligned nanofibers in the outer and inner layers are more robust and tear-resistant during surgical procedures thanks to an isotropic mechanical property provided by the random nanofibers. However, it remains unclear whether the random nanofibers will interfere with the aligned nanofibers to alter the extension pattern of the neurites and impede regeneration. To answer this question, we seeded dorsal root ganglia (DRG) on a double-layered scaffold, with aligned and random nanofibers on the top and bottom layers, respectively, and evaluated the outgrowth of neurites. The random nanofibers in the bottom layer exerted a negative impact on the extension of neurites projecting from the DRG, giving neurites a less ordered structure compared to those cultured on a single layer of aligned nanofibers. The negative impact of the random nanofibers could be effectively mitigated by preseeding the double-layered scaffold with Schwann cells. DRG cultured on top of such a scaffold exhibited a neurite outgrowth pattern similar to that for DRG cultured on a single layer of aligned nanofibers. We further fabricated bilayer NGCs from the double-layered scaffolds and tested their ability to facilitate nerve regeneration in a rat sciatic nerve injury model. Both histomorphometric analysis and functional characterization demonstrated that bilayer NGCs with an inner surface that was preseeded with Schwann cells could reach 54%, 64.2%, and 74.9% of the performance of isografts in terms of nerve fiber number, maximum isometric tetanic force, and mass of the extensor digitorum longus muscle, respectively. It can be concluded that the bilayer NGCs hold great potential in facilitating motor axon regeneration and functional motor recovery.

Astrogliosis and HSP 70 activation in neonate rats' brain exposed to sodium metavanadate through lactation

The effect of sodium metavanadate (NaVO3) exposure on lipid oxidative damage in the CNS of suckling rats was studied. Using histological markers of cellular injury, we also studied the morphological alterations of neurons and astroglial cells in different regions of neonate rats CNS after NaVO3 exposure. Dams of treated litters were intraperitoneally injected with 3mgNaVO3/kgbody weight/day during 12days starting on post-natal day (PND) 10. On the 21st PND, four pups of each litter were sacrificed by decapitation and six brain areas were removed for lipid peroxidation assay by the thiobarbituric acid (TBA) reaction, the other four were transcardially perfused-fixed and their brains were removed and cut with a cryostat. Brain sections were processed for: NADPHd histochemistry and anti-HSP70, anti-GFAP and anti-S100 immunohistochemistry. The relative optical density of the NADPHd stained layers and of S100 (+) astrocytes and the GFAP (+) astrocyte surface area in Cer and Hc were measured. Although MDA levels, S100 immunostaining and NADPHd activity didn't show differences between experimental and control groups, both astrogliosis and HSP70 activation were detected in Cer, while only the former was detected in Hc of V-exposed pups.

The S100B protein in biological fluids: more than a lifelong biomarker of brain distress

S100B is a calcium-binding protein concentrated in glial cells, although it has also been detected in definite extra-neural cell types. Its biological role is still debated. When secreted, S100B is believed to have paracrine/autocrine trophic effects at physiological concentrations, but toxic effects at higher concentrations. Elevated S100B levels in biological fluids (CSF, blood, urine, saliva, amniotic fluid) are thus regarded as a biomarker of pathological conditions, including perinatal brain distress, acute brain injury, brain tumors, neuroinflammatory/neurodegenerative disorders, psychiatric disorders. In the majority of these conditions, high S100B levels offer an indicator of cell damage when standard diagnostic procedures are still silent. The key question remains as to whether S100B is merely leaked from injured cells or is released in concomitance with both physiological and pathological conditions, participating at high concentrations in the events leading to cell injury. In this respect, S100B levels in biological fluids have been shown to increase in physiological conditions characterized by stressful physical and mental activity, suggesting that it may be physiologically regulated and raised during conditions of stress, with a putatively active role. This possibility makes this protein a candidate not only for a biomarker but also for a potential therapeutic target.

The role of receptor for advanced glycation end products (RAGE) in neuronal differentiation

The receptor for advanced glycation end products (RAGE) is a multiligand receptor protein thought to play an important role in neuronal differentiation. RAGE can bind a number of ligands and activate a variety of signalling pathways that lead to diverse downstream effects. Amphoterin and S100B are endogenous ligands, the interaction of which with RAGE is known to be involved in defined physiological processes. The present study investigated the spatiotemporal pattern of the expression for RAGE and its ligands, amphoterin and S100B, during neuronal differentiation of NT2/D1 cells. In this study, all three proteins were shown to increase with progression of neuronal differentiation as determined by Western blotting, raising the possibility that both amphoterin and S100B may interact with RAGE and have important functions during the process of cell differentiation. Moreover, blocking the activation of RAGE with neutralizing antibody in the presence of retinoic acid disrupted the progression of normal neuronal differentiation. Immunocytochemistry (ICC) studies showed that amphoterin partially colocalized with RAGE within differentiating NT2 cells, whereas S100B showed a high degree of colocalization. This result suggests that S100B is more likely to be the principal ligand for RAGE during the differentiation process and that RAGE and amphoterin might have both independent and combined roles. Moreover, RAGE was expressed only in cells that were committed to a neuronal phenotype, suggesting direct involvement of RAGE in mediating cellular changes within differentiating neuronal cells. Further detailed studies are now required to characterize fully the role of RAGE during the neuronal differentiation period.

Smooth muscle proteins from Hirschsprung's disease facilitates stem cell differentiation

BACKGROUND AND AIMS

The transplantation of neural crest derived stem cells (NCSC's) is a potent alternative for the treatment of Hirschsprung's disease (HSCR). Cells to be transplanted should find an appropriate microenvironment to survive and differentiate. To investigate the quality of this microenvironment, effects of HSCR-smooth-muscle-protein extracts upon NCSC's were studied in vitro.

METHODS

Postnatal human gut from children undergoing colonic resection due to HSCR was divided in segments. Smooth muscle was dissected and homogenized. Glial-cell-line-derived-neurotrophic-factor (GDNF) concentration was measured in the homogenates from the individual segment using ELISA. NCSC's were exposed to protein extracts derived from ganglionic and aganglionic HSCR segments, and their effect upon neurite outgrowth, survival and branching was evaluated.

RESULTS

The amount of the factors varied considerably between the proximal and distal segments, and also from patient to patient. While extracts from proximal segments tended to have more prominent effects, all HSCR-muscle-protein extracts increased neuronal survival and network formation.

CONCLUSION

Muscle protein from aganglionic bowel supports the survival and outgrowth of NCSC's and is so an appropriate target for neural stem cell treatment.

Perinatal selective serotonin reuptake inhibitor exposure: impact on brain development and neural plasticity

Selective serotonin reuptake inhibitor (SSRI) medications are the most common antidepressant treatment used during pregnancy and the postpartum period. Up to 10% of pregnant women are prescribed SSRIs. Serotonin plays an integral part in neurodevelopment, and questions have been raised about the placental transfer of SSRIs and the effects of preventing reuptake of presynaptic serotonin on fetal neurodevelopment. Preclinical data is beginning to document a role of early exposure to SSRIs in long-term developmental outcomes related to a number of brain regions, such as the hippocampus, cortex and cerebellum. To date, the majority of preclinical work has investigated the developmental effects of SSRIs in the offspring of healthy mothers; however, more research is needed on the effects of these medications in the face of maternal adversity. This minireview will highlight emerging evidence from clinical and preclinical studies investigating the impact of perinatal SSRI exposure on brain development and neural plasticity.

Critical period of axoglial signaling between neuregulin-1 and brain-derived neurotrophic factor required for early Schwann cell survival and differentiation

During peripheral nervous system development, successful communication between axons and Schwann cells is required for proper function of both myelinated and nonmyelinated nerve fibers. Alternatively spliced proteins belonging to the neuregulin1 (NRG1) gene family of growth and differentiation factors are essential for Schwann cell survival and peripheral nerve development. Although recent studies have strongly implicated membrane-bound NRG1 forms (type III) in the myelination at late stages, little is known about the role of soluble, heparin-binding forms of NRG1 (type I/II) in regulating early Schwann cell development in vivo. These forms are rapidly released from axons in vitro by Schwann-cell-secreted neurotrophic factors and, unlike membrane-bound forms, have a unique ability to diffuse and adhere to heparan sulfate-rich cell surfaces. Here, we show that axon-derived soluble NRG1 translocates from axonal to Schwann cell surfaces in the embryonic chick between days 5 and 7, corresponding to the critical period of Schwann cell survival. Downregulating endogenous type I/II NRG1 signaling either with a targeted NRG1 antagonist or by shRNA blocks their differentiation from precursors into immature Schwann cells and increases programmed cell death, whereas upregulating NRG1 rescues Schwann cells. Exogenous BDNF also promotes Schwann cell survival through promoting the local release of axonal NRG1. Consistently, increased Schwann cell death occurs both in trkB knock-out mice and after knocking down axonal trkB in chick embryos, which can then be rescued with soluble NRG1. These findings suggest a localized, axoglial feedback loop through soluble NRG1 and BDNF critical for early Schwann cell survival and differentiation.

S100B protein, brain-derived neurotrophic factor, and glial cell line-derived neurotrophic factor in human milk

Background

Human milk contains a wide variety of nutrients that contribute to the fulfillment of its functions, which include the regulation of newborn development. However, few studies have investigated the concentrations of S100B protein, brain-derived neurotrophic factor (BDNF), and glial cell line-derived neurotrophic factor (GDNF) in human milk. The associations of the concentrations of S100B protein, BDNF, and GDNF with maternal factors are not well explored.

Methodology/Principal Findings

To investigate the concentrations of S100B protein, BDNF, and GDNF in human milk and characterize the maternal factors associated with their levels in human milk, human milk samples were collected at days 3, 10, 30, and 90 after parturition. Levels of S100B protein, BDNF, and GDNF, and their mRNAs in the samples were detected. Then, these concentrations were compared with lactation and other maternal factors. S100B protein levels in human milk samples collected at 3, 10, 30, and 90 d after parturition were 1249.79±398.10, 1345.05±539.16, 1481.83±573.30, and 1414.39±621.31 ng/L, respectively. On the other hand, the BDNF concentrations in human milk samples were 10.99±4.55, 13.01±5.88, 13.35±6.43, and 2.83±5.47 µg/L, while those of GDNF were 10.90±1.65, 11.38±1., 11.29±3.10, and 11.40±2.21 g/L for the same time periods. Maternal post-pregnancy body mass index was positively associated with S100B levels in human milk (r = 0.335, P = 0.030<0.05). In addition, there was a significant correlation between the levels of S100B protein and BDNF (z = 2.09, P = 0.037<0.05). Delivery modes were negatively associated with the concentration of GDNF in human milk.

Conclusions

S100B protein, BDNF, and GDNF are present in all samples of human milk, and they may be responsible for the long term effects of breast feeding.

S100B Protein, A Damage-Associated Molecular Pattern Protein in the Brain and Heart, and Beyond

S100B belongs to a multigenic family of Ca(2+)-binding proteins of the EF-hand type and is expressed in high abundance in the brain. S100B interacts with target proteins within cells thereby altering their functions once secreted/released with the multiligand receptor RAGE. As an intracellular regulator, S100B affects protein phosphorylation, energy metabolism, the dynamics of cytoskeleton constituents (and hence, of cell shape and migration), Ca(2+) homeostasis, and cell proliferation and differentiation. As an extracellular signal, at low, physiological concentrations, S100B protects neurons against apoptosis, stimulates neurite outgrowth and astrocyte proliferation, and negatively regulates astrocytic and microglial responses to neurotoxic agents, while at high doses S100B causes neuronal death and exhibits properties of a damage-associated molecular pattern protein. S100B also exerts effects outside the brain; as an intracellular regulator, S100B inhibits the postinfarction hypertrophic response in cardiomyocytes, while as an extracellular signal, (high) S100B causes cardiomyocyte death, activates endothelial cells, and stimulates vascular smooth muscle cell proliferation.

Age-dependent expression of S100beta in the brain of mice

S100beta is a soluble calcium binding protein released by glial cells. It has been reported as a neurotrophic factor that promotes neurite maturation and outgrowth during development. This protein also plays a role in axonal stability and in long term potentiation in the adult brain. The ability of S100beta to modulate neuronal morphology raises the important question whether there is an age-related difference in the expression of S100beta in the cerebral and cerebellar cortices of AKR strain mice and is this change is region specific. Our RT-PCR and Western blotting experiments show that the expression of S100beta gene in the cerebral and cerebellar cortices starts from 0 day, peaks at about 45 days. However, in 70-week old mice its expression is significantly up-regulated as compared to that of 20-week old mice. S100beta follows the same age-related pattern in both cerebral and cerebellar cortices. These results suggest that S100beta is important for brain development and establishment of proper brain functions. Up-regulation of S100beta in old age may have some role in development of age-related pathological systems in the brain.

Cerebrospinal fluid biomarkers in human prion diseases

Cerebrospinal fluid (CSF) is the main component of the brain extracellular space and participates in the exchange of many biochemical products in the CNS. Consequently, CSF contains a dynamic and complex mixture of proteins that reflect the physiological or pathological state of the CNS. Changes in the CSF proteome have been described in various neurodegenerative disorders. These alterations are also thought to reflect pathological changes in the brain, and thus understanding them will contribute to a better awareness of the pathophysiology that underlies these disorders. Proteomics offers a new methodology for the analysis of pathological changes and mechanisms occurring in neurodegenerative processes and provides the possibility of novel biomarker discovery in order to supplement faster, earlier and more precise diagnosis. In general, the following criteria have to be applied in order to qualify a protein or a gene as a potential biomarker: the selected parameters have to be sensitive (able to detect the abnormalities at early stage of disease), specific (to allow differential diagnosis), reproducible with a high positive predictive value, and should allow for disease monitoring as well as a potential therapeutic response. In Creutzfeldt–Jakob disease, two major approaches have been followed that aim to detect the pathological form of the prion protein (PrPSc) in various peripheral tissues, while other approaches look for surrogate parameters that are a consequence of the neurodegenerative process. While the amount of abnormal disease-related PrPSc in CSF and blood in human transmissible spongiform encephalopathies appears to be extremely low, the development of a PrPSc-based biomarker was hampered by technical problems and detection limits. However, a variety of other proteins have been investigated in the CSF, and recently a variety of potential biomarkers have been reported that contribute to clinical diagnosis. Already established markers are 14-3-3, β-amyloid, tau-protein and phosphorylated isoforms, S100b, as well as neuron-specific enolase. Since some of these markers display certain limitations, the search continues. This review summarizes current knowledge of biomarker development in prion diseases and discusses perspectives for new approaches.

Exposure to CSF from sporadic amyotrophic lateral sclerosis patients induces morphological transformation of astroglia and enhances GFAP and S100beta expression

We have earlier shown that cerebrospinal fluid (CSF) of amyotrophic lateral sclerosis (ALS) patients' produces selective degeneration of motor neurons, both in vitro as well as in vivo. The present study further evaluates the effect of ALS-CSF on the astrocytes in embryonic rat spinal cord cultures. We quantified the number of flat and process-bearing astrocytes in spinal cord cultures exposed to ALS-CSF and compared them against controls. In addition, GFAP and S100beta expression were quantified by Western blot and measurement of immunofluorescence intensity respectively. We found higher number of process-bearing astrocytes in the cultures exposed to ALS-CSF. Both these proteins increased significantly in cultures exposed to ALS-CSF. Our results provide evidence that astroglia respond to toxic factor(s) present in ALS-CSF by undergoing morphological transformation from flat to process bearing which is further confirmed by elevated expression of GFAP and S100beta. The above changes could possibly alter the microenvironment hastening the motor neuron degeneration.

S100beta and fibroblast growth factor-2 are present in cultured Schwann cells and may exert paracrine actions on the peripheral nerve injury

PURPOSE

The neurotrophic factor fibroblast growth factor-2 (FGF-2, bFGF) and Ca++ binding protein S100beta are expressed by the Schwann cells of the peripheral nerves and by the satellite cells of the dorsal root ganglia (DRG). Recent studies have pointed out the importance of the molecules in the paracrine mechanisms related to neuronal maintenance and plasticity of lesioned motor and sensory peripheral neurons. Moreover, cultured Schwann cells have been employed experimentally in the treatment of central nervous system lesions, in special the spinal cord injury, a procedure that triggers an enhanced sensorymotor function. Those cells have been proposed to repair long gap nerve injury.

METHODS

Here we used double labeling immunohistochemistry and Western blot to better characterize in vitro and in vivo the presence of the proteins in the Schwann cells and in the satellite cells of the DRG as well as their regulation in those cells after a crush of the rat sciatic nerve.

RESULTS

FGF-2 and S100beta are present in the Schwann cells of the sciatic nerve and in the satellite cells of the DRG. S100beta positive satellite cells showed increased size of the axotomized DRG and possessed elevated amount of FGF-2 immunoreactivity. Reactive satellite cells with increased FGF-2 labeling formed a ring-like structure surrounding DRG neuronal cell bodies.Reactive S100beta positive Schwann cells of proximal stump of axotomized sciatic nerve also expressed higher amounts of FGF-2.

CONCLUSION

Reactive peripheral glial cells synthesizing FGF-2 and S100beta may be important in wound repair and restorative events in the lesioned peripheral nerves.

Neonatal S100B protein levels after prenatal exposure to selective serotonin reuptake inhibitors

OBJECTIVE

This study investigated neonatal S100B levels as a biomarker of prenatal selective serotonin reuptake inhibitor (SSRI) exposure.

METHODS

Maternal (delivery; N = 53) and neonatal (cord; N = 52) serum S100B levels were compared between prenatally SSRI-exposed (maternal, N = 36; neonatal, N = 37; duration: 230 +/- 71 days) and nonexposed (maternal, N = 17; neonatal, N = 15) groups. Measures of maternal depression and anxiety symptoms were assessed during the third trimester (33-36 weeks), and neonatal outcomes, including Apgar scores, birth weight, gestational age at birth, and symptoms of poor neonatal adaptation, were recorded.

RESULTS

S100B levels were significantly lower in prenatally SSRI-exposed neonates than in nonexposed neonates, controlling for gestational age and third-trimester maternal mood (P = .036). In contrast, SSRI-exposed mothers had significantly higher maternal serum S100B levels, compared with nonexposed mothers (P = .014), even controlling for maternal mood in the third trimester. S100B levels were not associated with maternal or neonatal drug levels, duration of prenatal exposure, demographic variables, or risk for poor neonatal adaptation.

CONCLUSIONS

Prenatal SSRI exposure was associated with decreased neonatal serum S100B levels, controlling for prenatal maternal mood. Neonatal S100B levels did not reflect neonatal behavioral outcomes and were not related to pharmacologic indices. These findings are consistent with prenatal alcohol and cocaine exposures, which also alter central serotonin levels.

Differential effects of interleukin-1beta and S100B on amyloid precursor protein in rat retinal neurons

Purpose:

Interleukin-1β (IL-1β) and S100B calcium binding protein B (S100B) have been implicated in the pathogenesis of Alzheimer’s disease. Both are present in and around senile plaques and have been shown to increase levels of amyloid precursor protein (APP) mRNA in vitro. However, it is not known how either of these substances affects APP in vivo.

Methods:

We have studied the effects of IL-1β and S100B on the expression and processing of APP using a retinal-vitreal model. We have also investigated the effect of amyloid beta peptide (Aβ) on APP in the same system and the regulation of S100B production by Aβ and IL-1β from retinal glial cells.

Results:

Retinal ganglion cells constitutively express APP. However, after intravitreal injection of IL-1β or Aβ there was a marked reduction in APP levels as detected by Western blotting and IL-1β produced a decrease in APP immunoreactivity (IR). Nissl staining showed that the integrity of the injected retinas was unchanged after injection. Two days after S100B injection, there was a small reduction in APP-IR but this was accompanied by the appearance of some intensely stained large ganglion cells and there was some up-regulation in APP holoprotein levels on Western blot. Seven days post-S100B injection, these large, highly stained cells had increased in number throughout the retina. Injection of Aβ and IL-1β also caused an increase in S100B production within the retinal Müller glial cells.

Conclusion:

These results support the hypothesis that S100B (a glial-derived neurotrophic factor) and IL-1β (a pro-inflammatory cytokine) can modulate the expression and processing of APP in vivo and so may contribute to the progression of Alzheimer’s disease.

S100beta upregulation: a possible mechanism of deltamethrin toxicity and motor coordination deficits

Deltamethrin (DLT) is a type II synthetic pyrethroid with insecticidal properties. It has been considered safe to humans. Excessive exposure of DLT is being variously reported, recently, to cause potential neurotoxicity in adults, as characterized by ataxia, loss of coordination, hyperexcitability, convulsions and paralysis. However, limited information is available on its impact at lower/safe to human doses during development. The present study was designed to assess the postnatal (P) exposure of DLT (as low as 0.7 mg/kg, i.p.) on S-100beta expression in developing rat cerebellum and its impact on Purkinje cell morphogenesis and dendritogenesis, and subsequent spontaneous motor activity (SMA) deficits. Wistar rat pups born to healthy mothers were injected with DLT (Sigma) at a dosage of 0.7 mg/kg body wt., i.p. dissolved in DMSO (Sigma) during P0-7th (DLT-I) and P9-13th day (DLT-II). The control pups were injected with equivalent volumes of DMSO. The pups of both the groups were used to assess the spontaneous motor activity P21 onwards. The cryocut sections (30 microm) of the cerebella were used for anti-S-100beta antibody labeling using streptavidin biotin HRP method. An upregulation of S-100beta expression in Bergmann glial fibers was recorded at P12 and P15 day preparations in both DLT-I and DLT-II treated groups. However, such upregulation of S-100beta was more prominent in DLT-II treated group animals with a large number of strongly S-100beta immunopositive astrocytes flanking around the Purkinje neurons. In Golgi preparation the Purkinje neurons in DLT treated groups had reduced dendritic arbor with short primary dendrites and much reduced dendritic branches which appeared stumpy and hypertrophied. The granule cell proliferation and migration as well as Purkinje cell morphogenesis and dendritogenesis are affected following DLT exposure in the present investigation. This may also affect the mossy fiber-granule cell-parallel pathway formation which in turn may decrease the firing of Purkinje cells (GABAergic inhibitory projections) and thus an increase in the output of the neurons in the deep cerebellar nuclei neurons and disturbed motor coordination.

S100B's double life: intracellular regulator and extracellular signal

The Ca2+-binding protein of the EF-hand type, S100B, exerts both intracellular and extracellular functions. Recent studies have provided more detailed information concerning the mechanism(s) of action of S100B as an intracellular regulator and an extracellular signal. Indeed, intracellular S100B acts as a stimulator of cell proliferation and migration and an inhibitor of apoptosis and differentiation, which might have important implications during brain, cartilage and skeletal muscle development and repair, activation of astrocytes in the course of brain damage and neurodegenerative processes, and of cardiomyocyte remodeling after infarction, as well as in melanomagenesis and gliomagenesis. As an extracellular factor, S100B engages RAGE (receptor for advanced glycation end products) in a variety of cell types with different outcomes (i.e. beneficial or detrimental, pro-proliferative or pro-differentiative) depending on the concentration attained by the protein, the cell type and the microenvironment. Yet, RAGE might not be the sole S100B receptor, and S100B's ability to engage RAGE might be regulated by its interaction with other extracellular factors. Future studies using S100B transgenic and S100B null mice might shed more light on the functional role(s) of the protein.

Serum S100B levels after meningioma surgery: A comparison of two laboratory assays

Background

S100B protein is a potential biomarker of central nervous system insult. This study quantitatively compared two methods for assessing serum concentration of S100B.

Methods

A prospective, observational study performed in a single tertiary medical center. Included were fifty two consecutive adult patients undergoing surgery for meningioma that provided blood samples for determination of S100B concentrations. Eighty samples (40 pre-operative and 40 postoperative) were randomly selected for batch testing. Each sample was divided into two aliquots. These were analyzed by ELISA (Sangtec) and a commercial kit (Roche Elecsys^®) for S100B concentrations. Statistical analysis included regression modelling and Bland-Altman analysis.

Results

A parsimonious linear model best described the prediction of commercial kit values by those determined by ELISA (y = 0.045 + 0.277*x, x = ELISA value, R² = 0.732). ELISA measurements tended to be higher than commercial kit measurements. This discrepancy increased linearly with increasing S100B concentrations. At concentrations above 0.7 μg/L the paired measurements were consistently outside the limits of agreement in the Bland-Altman display. Similar to other studies that used alternative measurement methods, sex and age related differences in serum S100B levels were not detected using the Elecsys^® (p = 0.643 and 0.728 respectively).

Conclusion

Although a generally linear relationship exists between serum S100B concentrations measured by ELISA and a commercially available kit, ELISA values tended to be higher than commercial kit measurements particularly at concentrations over 0.7 μg/L, which are suggestive of brain injury. International standardization of commercial kits is required before the predictive validity of S100B for brain damage can be effectively assessed in clinical practice.

Astrocyte phenotype in relation to Alzheimer-type pathology in the ageing brain

Astrocyte pathology occurs in association with Alzheimer's disease (AD) and in brain ageing, but is poorly characterised. We sought to define the detailed cellular pathology of astrocytes, the extent of population variation and the relationship to Alzheimer-type changes in a population-based cohort. Three staining patterns were associated with GFAP and excitatory amino acid transporter 2 (EAAT2): minimal, moderate or extensive immunoreactivity. GFAP and EAAT2 expression were inversely related (p=0.015), with trends to increased expression of GFAP (p=0.019) and decreased expression of EAAT2 (p=ns) with increasing Braak stage. GFAP and EAAT2 correlated incompletely with beta-amyloid and tau immunoreactivity. However, gliosis increased with increasing burden of neuritic (p=0.011), but not diffuse (p=ns), plaques. Double-staining revealed distinct subsets of astrocytes; GFAP(+)EAAT(-), GFAP(-)EAAT(+), or GFAP(+)EAAT(+). In contrast to the variation in GFAP and EAAT2, levels of EAAT1 and S100B showed consistent staining patterns. Alzheimer-type pathology only partially explains the variation in gliosis and astrocyte functional markers, suggesting that other factors contribute to the population variance in astrocyte pathology.

Cellular analysis of S100Beta and fibroblast growth factor-2 in the dorsal root ganglia and sciatic nerve of rodents. focus on paracrine actions of activated satellite cells after axotomy

The role of satellite cells, a type of peripheral glia, in the paracrine mechanisms related to neuronal maintenance and plasticity in the dorsal root ganglia (DRG) needs to be further investigated. This study employed immunohistochemistry and image analysis to investigate basic fibroblast growth factor (bFGF, FGF-2) and S100Beta immunoreactivities in the DRG and sciatic nerve of the rat and mouse. Well-characterized antibodies against bovine (residues 1-24) and rat (residues 1-23) FGF-2 were employed. Furthermore, the state of satellite cell reaction and changes in the FGF-2/S100Beta immunoreactivity were analyzed after axotomy of rat sciatic nerve. Scattered neurons and the majority of the satellite cells of the rat DRG and also Schwann cells of the rat sciatic nerve stained for S100Beta. In the mouse, strong S100Beta was encountered in the majority of sensory neurons and Schwann cells. Moderate FGF-2 (residues 1-24) immunoreactivity was found in scattered small size neurons of the rat DRG. A strong FGF-2 (residues 1-23) immunoreactivity was achieved in the satellite cells of rat DRG. Both FGF-2 antisera showed strong labeling in the mouse DRG sensory neurons. Activated satellite cells of the axotomized DRG possessed increased amount of FGF-2 and S100Beta immunoreactivity as demonstrated by quantitative image analysis. The proximal stump of the lesioned rat sciatic nerve showed increased FGF-2 (residues 1-24 and 1-23) in the Schwann cells, myelin sheaths, and neuronal fibers, without changes in the level of S100Beta immunoreactivity. Results suggested a possible interaction between FGF-2 and S100Beta in activated satellite cells of the DRG, which might trigger paracrine actions in the axotomized sensory neurons.

Central nervous system protection by resveratrol in streptozotocin-induced diabetic rats

The objective of the present study was to investigate the possible neuroprotective effect of resveratrol against streptozotocin-induced hyperglycaemia in the rat brain and medulla spinalis. Thirty adult male Wistar rats were divided into three groups as follows: control group, streptozotocin-induced diabetic-untreated group, and streptozotocin-induced diabetic resveratrol-treated group. Diabetes was induced by a single injection of streptozotocin (STZ) (60 mg/kg body weight). Three days after streptozotocin injection, resveratrol (10 mg/kg) was injected intraperiteonally daily over 6 weeks to the rats in the treatment group. Six weeks later, seven rats from each group were killed and the brain stem and cervical spinal cord were removed. The hippocampus, cortex, cerebellum, brain stem and spinal cord were dissected for biochemical studies (lipid peroxidation measuring malondialdehyde [MDA], xanthine oxidase [XO], nitric oxide [NO] and glutathione). MDA, XO and NO levels in hippocampus, cortex, cerebellum, brain stem and spinal cord in the streptozotocin-induced diabetic-untreated group increased significantly. Treatment with resveratrol significantly reduced MDA, XO and NO production and increased glutathione levels when compared to the streptozotocin-induced diabetic-untreated group. This study demonstrates that resveratrol is a potent neuroprotective agent against diabetic oxidative damage.

Expression of S100B during embryonic development of the mouse cerebellum

BACKGROUND

In the cerebellum of newborn S100B-EGFP mice, we had previously noted the presence of a large population of S100B-expressing cells, which we assumed to be immature Bergmann glial cells. In the present study, we have drawn on this observation to establish the precise spatio-temporal pattern of S100B gene expression in the embryonic cerebellum.

RESULTS

From E12.5 until E17.5, S100B was expressed in the primary radial glial scaffold involved in Purkinje progenitor exit from the ventricular zone and in the Sox9+ glial progenitors derived from it. During the same period coinciding with the primary phase of granule neuron precursor genesis, transient EGFP expression tagged the Pax6+ forerunners of granule precursors born in the cerebellar rhombic lip.

CONCLUSION

This study provides the first characterization of S100B-expressing cell types of the embryonic mouse cerebellum in a high-resolution map. The transient activation of the S100B gene distinguishes granule neuron precursors from all other types of precursors so far identified in the rhombic lip, whereas its activation in radial glial precursors is a feature of Bergmann cell gliogenesis.

Expression of glial progenitor markers p75NTR and S100 protein in the developing mouse parathyroid gland

Drosophila glial cells missing (Drosophila Gcm) is a transcription factor that is required for the differentiation of glial cells. Gcm2, a mouse homologue of Drosophila Gcm, is a master regulatory gene of parathyroid development and is expressed in the parathyroid rudiment. We have found that the mouse parathyroid exhibits the glial progenitor markers, p75(NTR) and S100 protein, during fetal development. At embryonic day 11.5 (E11.5), a bulge of the parathyroid rudiment is formed in the cranial part of the third pharyngeal pouch. The rudiment exhibits immunoreactivity for p75(NTR) and S100 protein, in addition to secretory protein 1/chromogranin A. While the thymus rudiment, which arises from the caudal part of the third pharyngeal pouch, is moving downwards, the parathyroid is attached to the top of thymus. The parathyroid comes into contact with the thyroid lobe at E13.5 and then separates from the thymus. The parathyroid maintains intense immunoreactivity for p75(NTR) and S100 protein during the migration and development in the thyroid lobe. The co-localization of p75(NTR) and S100 in the developing parathyroid cells has been confirmed by confocal microscopy. Other glial markers, viz. glial fibrillary acidic protein, Sox10, vimentin and nestin, are not expressed in the parathyroid at any stage of development. The neural progenitor markers, neurofilament 160 and TuJ1, are also absent from the parathyroid. Taken together, we suggest that Gcm2 supplies only some glial progenitor characteristics to the parathyroid rudiment.

Neuroprotective effect of etomidate in the central nervous system of streptozotocin-induced diabetic rats

It is well known that hyperglycaemia due to diabetes mellitus leads to oxidative stress in the central nervous system. Oxidative stress plays important role in the pathogenesis of neurodegenerative changes. In the present study we investigated the possible neuroprotective effect of etomidate against streptozotocin-induced (STZ-induced) hyperglycaemia in the rat brain and spinal cord. A total of 40 rats were used in this study. Rats were divided into four groups: sham-control, diabetic, diabetic-etomidate treated and vehicle for etomidate treatment group. Diabetes mellitus was induced by a single injection of streptozotocin (60 mg/kg body weight). Three days after streptozotocin injection, etomidate (2 mg/kg) was injected intraperitoneally for etomidate group and lipid emulsion (10%) for vehicle group was injected with corresponding amount intraperitoneally every day for 6 weeks. Six weeks after streptozotocin injection, seven rats from each group were killed and brain, brain stem and cervical spinal cord were removed. The hippocampus, cortex, cerebellum, brain stem and spinal cord were dissected for the biochemical analysis (the level of malondialdehyde [MDA], total nitrite, reduced glutathione [GSH], and xanthine oxidase [XO] activity). STZ-induced diabetes resulted in significantly elevation of MDA, XO and nitrite levels in the hippocampus, cortex, cerebellum, brain stem and spinal cord of the rats (P < 0.05) while etomidate treatment provided significantly lower values (P < 0.05). This study demonstrated that etomidate have neuroprotective effect on the neuronal tissue against the diabetic oxidative damage.

TNF alpha affects the expression of GFAP and S100B: implications for Alzheimer's disease

Neurodegenerative disorders such as Alzheimer's disease are characterized by increased intracellular and extracellular concentrations of the astrocytic proteins glial fibrillary acidic protein (GFAP) and S100B. The present study examined the potential contribution of tumor necrosis factor alpha (TNFalpha) to these changes by measuring astrocyte viability along with the intracellular and extracellular expression of GFAP and S100B following exposure to this cytokine. Although TNFalpha did not affect astrocyte viability, the extracellular levels of both proteins were increased three-fold with associated reductions in immunocytochemical labeling.

Neuroprotective effect of mexiletine in the central nervous system of diabetic rats

Both experimental and clinical studies suggests that oxidative stress plays an important role in the pathogenesis of diabetes mellitus type 1 and type 2. Hyperglycaemia leads to free radical generation and causes neural degeneration. In the present study we investigated the possible neuroprotective effect of mexiletine against streptozotocin-induced hyperglycaemia in the rat brain and spinal cord. 30 adult male Wistar rats were divided into three groups: control, diabetic, and diabetic-mexiletine treated group. Diabetes mellitus was induced by a single injection of streptozotocin (60 mg/kg body weight). Mexiletine (50 mg/kg) was injected intraperitoneally every day for six weeks. After 6 weeks the brain, brain stem and cervical spinal cord of the rats were removed and the hippocampus, cortex, cerebellum, brain stem and spinal cord were dissected for biochemical analysis (the level of Malondialdehide [MDA], Nitric Oxide [NO], Reduced Glutathione [GSH], and Xanthine Oxidase [XO] activity). MDA, XO and NO levels in the hippocampus, cortex, cerebellum, brain stem and spinal cord of the diabetic group increased significantly, when compared with control and mexiletine groups (P < 0.05). GSH levels in the hippocampus, cortex, cerebellum, brain stem and spinal cord of the diabetic group decreased significantly when compared with control and mexiletine groups (P < 0.05). This study demonstrates that mexiletine protects the neuronal tissue against the diabetic oxidative damage.

The astroglial-derived S100beta protein stimulates the expression of nitric oxide synthase in rodent macrophages through p38 MAP kinase activation

S100beta is an astroglial-derived Ca2+ -binding protein having neurotrophic role on neurons and glial cells. An aberrant S100beta production has been observed in neurodegenerative disease, as Alzheimer's disease and Down syndrome. S100beta is responsible to start up a gliotic reaction by the release of pro-inflammatory mediators, including nitric oxide (NO) and cytokines from microglia and astrocytes, which are, in turn, deleterious for neurons. Interestingly, pro-inflammatory effect of S100beta seems not be restricted into the brain. Macrophages play a pivotal role in inflammatory diseases, occurring both in the brain and in the periphery. In this study, we tested the hypothesis that S100beta may affect macrophage functions, amplifying thus the inflammatory process. Our results demonstrate that S100beta stimulates both NO production and iNOS protein transcription and expression in J774 and rat peritoneal macrophages. NO production was concentration and time-dependently inhibited by two iNOS inhibitors, L-NAME and SMT. We also demonstrated that S100beta induced oxidative stress by increasing H2O2 production and lipid peroxidation of cell membrane in both macrophage types. The pro-oxidant potential of S100beta activates p38 MAP kinase (MAPK), which has been described to directly activate NF-kappaB. In our study, SB203580, a p38 MAPK inhibitor, and two NF-kappaB inhibitors, TLCK and BAY 11-7082, decreased both NO production and iNOS protein transcription and expression in S100beta-stimulated J774 and peritoneal rat macrophages. Moreover, additional studies demonstrated that S100beta affected also TNF-alpha protein expression in J774 macrophages. In conclusion, our results highlight the potential role of S100beta during an inflammatory scenario identifying macrophages as a novel S100beta-responsive cell-type.

Increased serum S100B in elderly, chronic schizophrenic patients: negative correlation with deficit symptoms

In schizophrenia, elevations of serum and CSF S100B levels have been reported and related to state of the disease and negative symptoms. In elderly chronic schizophrenic inpatients with stable medication, S100B may be increased and correlated to psychopathology and neuropsychological deficits. We have measured serum levels of S100B in 41 elderly, chronic schizophrenic patients and 23 age- and gender-matched controls using an immunoluminometric assay. In patients, we assessed detailed psychopathology and neuropsychological performance and determined serum levels of haloperidol, clozapine and its two main metabolites desmethylclozapine and clozapine metabolite N-oxid by HPLC. S100B levels were increased in elderly chronic schizophrenic patients compared to healthy controls. In patients, levels were negatively correlated with deficit symptoms and positively with age. There were no significant differences of S100B between medication groups and no correlation with serum levels of antipsychotics or neuropsychological scores. Elevations of S100B in elderly chronic schizophrenic patients may be related to an active disease process lasting until old-age. Correlations point to the impact of S100B in neuroplasticity and ageing. Post-mortem studies should clarify the presence of altered S100B function in the brain and its relationship to neuroplastic or neurodegenerative processes.

Protective effects of melatonin against ethanol-induced reactive gliosis in hippocampus and cortex of young and aged rats

Evidence has been accumulated indicating that chronic ethanol consumption leads to direct or indirect changes in the viability of central nervous system cells. The effects of aging and chronic ethanol consumption on glial markers [glial fibrillary acidic protein (GFAP) and S100B] and oxidant and antioxidant status of rats were studied. Furthermore, protective effects of melatonin against aging and alcohol consumption were also assayed. Chronic ethanol administration to young and aged rats produced an increase in lipid peroxidation, and a decline in glutathione (GSH) levels, which was significantly reversed by the co-administration of melatonin. Lipid peroxidation status was markedly affected in aged rats treated with alcohol compared to the young rats. An age-related increase in GFAP and S100B levels were found in the cortex and hippocampus. Long-term alcohol exposure resulted in distinct elevation in GFAP content in young rats (P < 0.01) while there was less increase in the cortex of aged rats (P < 0.05). In old rats, hippocampal GFAP levels were not significantly changed by alcohol treatment (P > 0.05). Co-administration of melatonin with alcohol significantly reduced GFAP contents both in the hippocampus (P < 0.01) and cortex (P < 0.001) of aged rats. No significant effects of alcohol treatment were found on the levels of neuron-specific enolase (NSE) in aged rats. This finding suggests that melatonin exerts its protective effect on injured nervous tissues by scavenging free radicals and stabilizing glial activity against the damaging effects of ethanol and aging. Furthermore, this work suggests that the signal to initiate gliosis is mediated, at least indirectly, by free radical formation.

Glia and their cytokines in progression of neurodegeneration

A glia-mediated, inflammatory immune response is an important component of the neuropathophysiology of Alzheimer's disease, of the midlife neurodegeneration of Down's syndrome, and of other age-related neurodegenerative conditions. All of these conditions are associated with early and often dramatic activation of, and cytokine overexpression in, microglia and astrocytes, sometimes decades before pathological changes consistent with a diagnosis of Alzheimer's disease are apparent, as in patients with Down's syndrome or head injury. Brains of normal elderly individuals also often show Alzheimer-type neuropathological changes, although to a lesser degree than those seen in Alzheimer's disease itself. These normal age-related glial changes, likely a response to the normal wear and tear of the aging process, raise the threshold of glial activation and thus may explain the fact that even genetically determined Alzheimer's disease, resulting from genetic mutations such as those in beta-amyloid precursor protein and presenilins or from genetic duplication such as of chromosome 21, only shows the full manifestation of the disease decades after birth. In the more common sporadic form of Alzheimer's disease, age-related increases in glial activation and expression of cytokines may act in synergy with other genetic and acquired environmental risks to culminate in the development of disease.

Localization of 5α-reductase in the rat main olfactory bulb

The enzyme steroid 5alpha-reductase catalyzes the production of dihydroprogesterone and dihydrotestosterone, which were recently recognized as neurosteroids in the brain with variably potential neuroactivity. The present study reports for the first time detailed localization of 5alpha-reductase type 1 in the rat main olfactory bulb. The occurrence of 5alpha-reductase in the olfactory bulb was detected by reverse transcription-polymerase chain reaction and Western blotting analyses. In addition, the enzyme activity was also detected by thin layer chromatography. Immunocytochemistry showed that 5alpha-reductase immunoreactive cells of variable intensity were present in all layers of the olfactory bulb. Multiple immunolabeling revealed that 5alpha-reductase was mainly localized in glial cells, namely, in S-100beta- and glial fibrillary acidic protein-immunoreactive astrocytes, 2', 3'-cyclic nucleotide 3'-phosphodiesterase (CNPase)-immunoreactive oligodendrocytes, and in S-100beta- and neuropeptide-Y-immunoreactive olfactory ensheathing cells, whereas the bulbar neurons exhibited little immunoreactivity. Quantitative analysis revealed that the number of 5alpha-reductase-immunoreactive cells was greatest in the olfactory nerve layer. The most intense 5alpha-reductase-immunoreactivity was found in the olfactory ensheathing cells, and next in the CNPase-immunoreactive cells. The 5alpha-reductase in the olfactory bulb was expressed constantly throughout different ages and sexes and in neutered and hypophysectomized rats. Thus, 5alpha-reductase may contribute via 5alpha-reduced metabolites to the formation and maintenance of olfactory inputs and outputs, which were closely associated with the olfactory ensheathing cells and the oligodendrocytes, respectively.

S100B-stimulated NO production by BV-2 microglia is independent of RAGE transducing activity but dependent on RAGE extracellular domain

The Ca(2+)-modulated protein, S100B, is expressed in high abundance in and released by astrocytes. At the low levels normally found in the brain, extracellular S100B acts as a trophic factor, protecting neurons against oxidative stress and stimulating neurite outgrowth through its binding to the receptor for advanced glycation end products (RAGE). However, upon accumulation in the brain extracellular space, S100B might be detrimental to neurons. At relatively high concentrations, S100B stimulates NO release by microglia in the presence of lipid A or interferon-gamma (IFN-gamma). We analyzed further the S100B-microglia interaction to elucidate the molecular mechanism by which the protein brings about this effect. We found that S100B increased NO release by BV-2 microglia by stimulating reactive oxygen species (ROS) production and activating the stress-activated kinases, p38 and JNK. However, S100B stimulated NO production to the same extent in microglia overexpressing a transduction-incompetent mutant of RAGE and in microglia overexpressing full-length RAGE, with a significantly smaller effect in mock-transfected microglia. This suggests that the RAGE transducing activity has little or no role in S100B-stimulated NO production by microglia, whereas RAGE extracellular domain is important, probably serving to concentrate S100B on the BV-2 cell surface. On the other hand, S100B stimulated NF-kappaB transcriptional activity in BV-2 microglia in a manner that was strictly dependent on RAGE transducing activity, pointing to additional, RAGE-mediated effects of the protein on microglia that remain to be investigated.

Characterisation of matrix metalloproteinases and the effects of a broad-spectrum inhibitor (BB-1101) in peripheral nerve regeneration

The effect of treatment with a broad-spectrum inhibitor (BB1101) of the matrix metalloproteinases (MMPs) on nerve regeneration and functional recovery after nerve crush was examined. Drug treatment had no effect on latency but from 63 days the compound muscle action potential was significantly increased and was no different to that in the sham-operated controls at 72 days. Levels of MMP mRNA expression, and the localisation and activity of MMP proteins, were examined in rats for a 2 month period following a nerve crush injury, and compared with sham-operated controls. The mRNA of all the MMPs studied was up-regulated by 5-10 days after nerve crush, and they remained up-regulated for 40-63 days, except for MMP-9 which was down-regulated by 10 days. MMP immunoreactivity was localised to Schwann cells, macrophages and endothelial cells, and with the exception of membrane type 1-MMP (MT1-MMP), it was more intense after nerve crush compared with sham-operated controls. Regenerating axons showed immunoreactivity for MMP-2 and MMP-3. In situ zymography confirmed that the activity of MMPs in the nerve was increased following crush but that the activity was greatly reduced in rats treated with BB-1101. Thus despite the inhibition of MMPs by BB-1101, the drug did not appear to essentially affect nerve degeneration or regeneration following nerve crush but that it could be beneficial in promoting the more effective reinnervation of muscles possibly by actions at the level of the muscles.

Amphoterin as an extracellular regulator of cell motility: from discovery to disease

Amphoterin is a ubiquitous and highly conserved protein previously considered solely as a chromatin-associated, nuclear molecule. Amphoterin is released into the extracellular space by various cell types, and plays an important role in the regulation of cell migration, differentiation, tumorigenesis and inflammation. This paper reviews recent research on the mechanistic background underlying the biology of secreted amphoterin, with an emphasis on the role of amphoterin as an autocrine/paracrine regulator of cell migration.

Amyotrophic lateral sclerosis: disease stage related changes of tau protein and S100 beta in cerebrospinal fluid and creatine kinase in serum

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease leading to progressive cell death of upper and lower motor neurons and reactive astrogliosis. Two proteins which may be relevant in this respect (tau and S100 beta) were studied in cerebrospinal fluid (CSF) next to routine parameters in 20 patients with sporadic ALS and 20 age-matched controls. Serum levels of creatine kinase (CK) were also determined to monitor the muscular involvement. S100 beta showed a significant decrease in CSF over the disease course (P=0.024). CSF tau as well as serum CK were elevated in 70% of the ALS patients. While highest CSF tau levels were found rather in the early disease stages, serum CK showed a shift of the peak values to several months later. Elevation of the CSF/serum albumin quotient occurred in 20% of the cases most likely representing a non-specific finding in ALS.

S100B causes apoptosis in a myoblast cell line in a RAGE-independent manner

S100B, a Ca(2+)-modulated protein with both intracellular and extracellular regulatory roles, is most abundant in astrocytes, is expressed in various amounts in several non-nervous cells and is also found in normal serum. Astrocytes secrete S100B, and extracellular S100B exerts trophic and toxic effects on neurons depending on its concentration, in part by interacting with the receptor for advanced glycation end products (RAGE). The presence of S100B in normal serum and elevation of its serum concentration in several non-nervous pathological conditions suggest that S100B-expressing cells outside the brain might release the protein and S100B might affect non-nervous cells. Recently we reported that at picomolar to nanomolar doses S100B inhibits rat L6 myoblast differentiation via inactivation of p38 kinase in a RAGE-independent manner. We show here that at >or=5 nM in the absence of and at >100 nM in the presence of serum S100B causes myoblast apoptosis via stimulation of reactive oxygen species (ROS) production and inhibition of the pro-survival kinase, extracellular signal-regulated kinase (ERK)1/2, again in a RAGE-independent manner. Together with our previous data, the present results suggest that S100B might participate in the regulation of muscle development and regeneration by two independent mechanism, i.e., by inhibiting crucial steps of the myogenic program at the physiological levels found in serum and by causing elevation of ROS production and myoblast apoptosis following accumulation in serum and/or muscle extracellular space. Our data also suggest that RAGE has no role in the transduction of S100B effects on myoblasts, implying that S100B can interact with more than one receptor to affect its target cells.