S100beta induces neuronal cell death through nitric oxide release from astrocytes

Serotonin 1A Receptors on Astrocytes as a Potential Target for the Treatment of Parkinson's Disease

Astrocytes are the most abundant neuron-supporting glial cells in the central nervous system. The neuroprotective role of astrocytes has been demonstrated in various neurological disorders such as amyotrophic lateral sclerosis, spinal cord injury, stroke and Parkinson’s disease (PD). Astrocyte dysfunction or loss-of-astrocytes increases the susceptibility of neurons to cell death, while astrocyte transplantation in animal studies has therapeutic advantage. We reported recently that stimulation of serotonin 1A (5-HT_1A) receptors on astrocytes promoted astrocyte proliferation and upregulated antioxidative molecules to act as a neuroprotectant in parkinsonian mice. PD is a progressive neurodegenerative disease with motor symptoms such as tremor, bradykinesia, rigidity and postural instability, that are based on selective loss of nigrostriatal dopaminergic neurons, and with non-motor symptoms such as orthostatic hypotension and constipation based on peripheral neurodegeneration. Although dopaminergic therapy for managing the motor disability associated with PD is being assessed at present, the main challenge remains the development of neuroprotective or disease-modifying treatments. Therefore, it is desirable to find treatments that can reduce the progression of dopaminergic cell death. In this article, we summarize first the neuroprotective properties of astrocytes targeting certain molecules related to PD. Next, we review neuroprotective effects induced by stimulation of 5-HT_1A receptors on astrocytes. The review discusses new promising therapeutic strategies based on neuroprotection against oxidative stress and prevention of dopaminergic neurodegeneration.

Targeting neuroinflammation in Alzheimer's disease

Almost 47 million people suffer from dementia worldwide, with an estimated new case diagnosed every 3.2 seconds. Alzheimer’s disease (AD) accounts for approximately 60%–80% of all dementia cases. Given this evidence, it is clear dementia represents one of the greatest global public health challenges. Currently used drugs alleviate the symptoms of AD but do not treat the underlying causes of dementia. Hence, a worldwide quest is under way to find new treatments to stop, slow, or even prevent AD. Besides the classic targets of the oldest therapies, represented by cholinergic and glutamatergic systems, β-amyloid (Aβ) plaques, and tau tangles, new therapeutic approaches have other targets. One of the newest and most promising strategies is the control of reactive gliosis, a multicellular response to brain injury. This phenomenon occurs as a consequence of a persistent glial activation, which leads to cellular dysfunctions and neuroinflammation. Reactive gliosis is now considered a key abnormality in the AD brain. It has been demonstrated that reactive astrocytes surround both Aβ plaques and tau tangles. In this condition, glial cells lose some of their homeostatic functions and acquire a proinflammatory phenotype amplifying neuronal damage. So, molecules that are able to restore their physiological functions and control the neuroinflammatory process offer new therapeutic opportunities for this devastating disease. In this review, we describe the role of neuroinflammation in the AD pathogenesis and progression and then provide an overview of the recent research with the aim of developing new therapies to treat this disorder.

Effects of Oxaliplatin Treatment on the Enteric Glial Cells and Neurons in the Mouse Ileum

Oxaliplatin, currently used for treatment of colorectal and other cancers, causes severe gastrointestinal side effects, including nausea, vomiting, diarrhea, and constipation that are attributed to mucosal damage. However, delayed onset and long-term persistence of these side effects suggest that damage to the enteric nervous system (ENS) regulating physiological function of the gastrointestinal tract may also occur. The ENS comprises myenteric and submucosal neurons and enteric glial cells (EGCs). This study aimed to investigate the effects of oxaliplatin treatment on enteric neurons and EGCs within the mouse ileum. BALB/c mice received repeated intraperitoneal injections of oxaliplatin (3 mg/kg, 3 injections/week). Tissues were collected 3, 7, 14, and 21 days from the commencement of treatment. Decreases in glial fibrillary acidic protein-immunoreactive (IR) EGCs and protein gene product 9.5/β-Tubulin III-IR neurons as well as increase in s100β-IR EGCs after chronic oxaliplatin administration were observed in both the myenteric and submucosal plexi. Changes in EGCs were further observed in cross-sections of the ileum at day 14 and confirmed by Western blotting. Alterations in EGCs correlated with loss of myenteric and submucosal neurons in the ileum from oxaliplatin-treated mice. These changes to the ENS may contribute to the mechanisms underlying gastrointestinal side effects associated with oxaliplatin treatment.

Time-dependent uptake and trafficking of vesicles capturing extracellular S100B in cultured rat astrocytes

Astrocytes, the most heterogeneous glial cells in the central nervous system, contribute to brain homeostasis, by regulating a myriad of functions, including the clearance of extracellular debris. When cells are damaged, cytoplasmic proteins may exit into the extracellular space. One such protein is S100B, which may exert toxic effects on neighboring cells unless it is removed from the extracellular space, but the mechanisms of this clearance are poorly understood. By using time-lapse confocal microscopy and fluorescently labeled S100B (S100B-Alexa⁴⁸⁸ ) and fluorescent dextran (Dextran⁵⁴⁶ ), a fluid phase uptake marker, we examined the uptake of fluorescently labeled S100B-Alexa⁴⁸⁸ from extracellular space and monitored trafficking of vesicles that internalized S100B-Alexa⁴⁸⁸ . Initially, S100B-Alexa⁴⁸⁸ and Dextran⁵⁴⁶ internalized with distinct rates into different endocytotic vesicles; S100B-Alexa⁴⁸⁸ internalized into smaller vesicles than Dextran⁵⁴⁶ . At a later stage, S100B-Alexa⁴⁸⁸ -positive vesicles substantially co-localized with Dextran⁵⁴⁶ -positive endolysosomes and with acidic LysoTracker-positive vesicles. Cell treatment with anti-receptor for advanced glycation end products (RAGE) antibody, which binds to RAGE, a 'scavenger receptor', partially inhibited uptake of S100B-Alexa⁴⁸⁸ , but not of Dextran⁵⁴⁶ . The dynamin inhibitor dynole 34-2 inhibited internalization of both fluorescent probes. Directional mobility of S100B-Alexa⁴⁸⁸ -positive vesicles increased over time and was inhibited by ATP stimulation, an agent that increases cytosolic free calcium concentration ([Ca²⁺ ]_i ). We conclude that astrocytes exhibit RAGE- and dynamin-dependent vesicular mechanism to efficiently remove S100B from the extracellular space. If a similar process occurs in vivo, astroglia may mitigate the toxic effects of extracellular S100B by this process under pathophysiologic conditions. This study reveals the vesicular clearance mechanism of extracellular S100B in astrocytes. Initially, fluorescent S100B internalizes into smaller endocytotic vesicles than dextran molecules. At a later stage, both probes co-localize within endolysosomes. S100B internalization is both dynamin- and RAGE-dependent, whereas dextran internalization is dependent on dynamin. Vesicle internalization likely mitigates the toxic effects of extracellular S100B and other waste products.

Intracerebroventricular application of S100B selectively impairs pial arteriolar dilating function in rats

S100B is an astrocyte-derived protein that can act through the receptor for advanced glycation endproducts (RAGE) to mediate either "trophic" or "toxic" responses. Its levels increase in many neurological conditions with associated microvascular dysregulation, such as subarachnoid hemorrhage (SAH) and traumatic brain injury. The role of S100B in the pathogenesis of microvasculopathy has not been addressed. This study was designed to examine whether S100B alters pial arteriolar vasodilating function. Rats were randomized to receive (1) artificial cerebrospinal fluid (aCSF), (2) exogenous S100B, and (3) exogenous S100B+the decoy soluble RAGE (sRAGE). S100B was infused intracerebroventricularly (icv) using an osmotic pump and its levels in the CSF were adjusted to achieve a concentration similar to what we observed in SAH. After 48 h of continuous icv infusion, a cranial window/intravital microscopy was applied to animals for evaluation of pial arteriolar dilating responses to sciatic nerve stimulation (SNS), hypercapnia, and topical suffusion of vasodilators including acetylcholine (ACh), s-nitroso-N-acetyl penicillamine (SNAP), or adenosine (ADO). Pial arteriolar dilating responses were calculated as the percentage change of arteriolar diameter in relation to baseline. The continuous S100B infusion for 48 h was associated with reduced responses to the neuronal-dependent vasodilator SNS (p<0.05) and the endothelial-dependent vasodilator ACh (p<0.05), compared to controls. The inhibitory effects of S100B were prevented by sRAGE. On the other hand, S100B did not alter the responses elicited by vascular smooth muscle cell-dependent vasodilators, namely hypercapnia, SNAP, or ADO. These findings indicate that S100B regulates neuronal and endothelial dependent cerebral arteriolar dilation and suggest that this phenomenon is mediated through RAGE-associated pathways.

STAT3 and its phosphorylation are involved in HIV-1 Tat-induced transactivation of glial fibrillary acidic protein

Human immunodeficiency virus type 1 (HIV-1) Tat protein is a major pathogenic factor in HIV-associated neurological diseases; it exhibits direct neurotoxicity and indirect astrocyte-mediated neurotoxicity. We have shown that Tat alone is capable of activating glial fibrillary acidic protein (GFAP) expression and inducing astrocytosis involving sequential activation of early growth response protein 1 (Egr-1) and p300. In this study, we determined the roles of signal transducer and activator of transcription 3 (STAT3) in Tat-induced GFAP transactivation. STAT3 expression and phosphorylation led to significant increases in GFAP transcription and protein expression. Tat expression was associated with increased STAT3 expression and phosphorylation in Tat-expressing astrocytes and HIV-infected astrocytes. GFAP, Egr-1 and p300 transcription and protein expression all showed positive response to STAT3 and its phosphorylation. Importantly, knockdown of STAT3 resulted in significant decreases in Tat-induced GFAP and Egr-1 transcription and protein expression. Taken together, these findings show that STAT3 is involved in and acts upstream of Egr1 and p300 in the Tat-induced GFAP transactivation cascade and suggest important roles of STAT3 in controlling astrocyte proliferation and activation in the HIV-infected central nervous system.

Assessment of both serum S-100B protein and neuropeptide-Y levels in childhood breath-holding spells

OBJECTIVE

Breath-holding spells are common paroxysmal events in children. Although the spells have a benign prognosis in the long term, they may be complicated by loss of consciousness, tonic-clonic movements, and occasionally seizures. Hence, this study aimed to measure the levels of serum S-100B proteins and neuropeptide-Y in the blood of children who experience breath-holding spells.

METHODS

The study groups consisted of 45 patients (13 females, 32 males) with breath-holding spells and a control group of 32 healthy individuals (12 females, 20 males). The serum S-100B levels were measured using commercially available ELISA kits. The neuropeptide-Y levels in the serum were measured with RayBio® Human/Mouse/Rat Neuropeptide Y ELISA kits.

RESULTS

The mean serum S-100B protein level of the breath-holding spells group was 56.38 ± 13.26 pg/mL, and of the control group, 48.53 ± 16.77 pg/mL. The mean neuropeptide-Y level was 62.29 ± 13.89 pg/mL in the breath-holding spells group and 58.24 ± 12.30 pg/mL in the control group. There were significant differences between the groups with respect to serum S-100B protein levels (p = 0.025), while there was no statistically significant difference in neuropeptide-Y levels between the breath-holding spells group and the control group (p = 0.192).

CONCLUSIONS

The findings of this study suggest that frequent and lengthy breath-holding may lead to the development of neuronal metabolic dysfunction or neuronal damage which is most likely related to hypoxia. In light of these findings, future studies should be conducted using biochemical and radiological imaging techniques to support these results.

Current and future bioanalytical approaches for stroke assessment

Efforts are underway to develop novel platforms for stroke diagnosis to meet the criteria for effective treatment within the narrow time window mandated by the FDA-approved therapeutic (<3 h). Blood-based biomarkers could be used for rapid stroke diagnosis and coupled with new analytical tools, could serve as an attractive platform for managing stroke-related diseases. In this review, we will discuss the physiological processes associated with stroke and current diagnostic tools as well as their associated shortcomings. We will then review information on blood-based biomarkers and various detection technologies. In particular, point of care testing that permits small blood volumes required for the analysis and rapid turn-around time measurements of multiple markers will be presented.

S100B and Glial Fibrillary Acidic Protein as Indexes to Monitor Damage Severity in an In Vitro Model of Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading and rising cause of death and disability worldwide. There is great interest in S100B and Glial Fibrillary Acid Protein (GFAP) as candidate biomarkers of TBI for diagnosis, triage, prognostication and drug development. However, conflicting results especially on S100B hamper their routine application in clinical practice. To try to address this question, we mimicked TBI damage utilizing a well-validated, simplified in vitro model of graded stretch injury induced in rat organotypic hippocampal slice cultures (OHSC). Different severities of trauma, from mild to severe, have been tested by using an equi-biaxial stretch of the OHSCs at a specified Lagrangian strain of 0 (controls), 5, 10, 20 and 50 %. OHSC were analysed at 3, 6, 18, 24, 48 and 96 h post-injury. Cell death, gene expressions and release into the culture medium of S100B and GFAP were determined at each time point. Gene expression and release of S100B slightly increased only in 20 and 50 % stretched OHSC. GFAP over-expression occurred in 10, 20 and 50 % and was inversely correlated with time post-injury. GFAP release significantly increased with time at any level of injury (p < 0.01 with respect to controls). Consequently, the total amount of GFAP released showed a strong linear relationship with the severity of injury (R(2) = 0.7662; p < 0.001). Under these experimental conditions, S100B seems to be useful in diagnosing only moderate to severe TBI-like injuries. Differently, GFAP demonstrates adequate biomarker requisites since its cellular release is affected by all grades of injury severity.

The clinical and diagnostic utility of S100B in preterm newborns

Preterm birth is still the most important cause of perinatal mortality and morbidity. Follow-up studies showed that the majority of neurological abnormalities during childhood are already present in the first week after birth. In this light, the knowledge of the timing of the insult and/or of the contributing factors is of utmost relevance in order to avoid adverse neurological outcome. Notwithstanding, the considerable advances in perinatal clinical care and monitoring, the early detection of cases at risk for brain damage is still a challenge because, when radiological pictures are still negative, brain damage may be already at a subclinical stage, with symptoms hidden by therapeutic strategies. Thus, it could be very relevant to measure quantitative parameters, such as neuroproteins, able to detect subclinical lesions at a stage when routine brain monitoring procedures are still silent. In the last decade, the assay of the brain-specific protein S100B in different biological fluids proved useful information on brain function and damage in the perinatal period. Therefore, the present study provides an overview of the most recent findings on S100B role as a reliable marker of brain development/damage in preterm high risk fetuses and newborns.

Recent and near-future advances in nucleic acid-based diagnosis of stroke

Stroke is a leading cause of death and disability in adults, but at present, treatment for ischemic stroke reaches only a small percentage of patients. This is because of the very short time window for treatment and the time-consuming evaluation involved. Intense efforts are underway to find novel approaches to expedite stroke diagnosis and treatment. In this review, we provide the rationale for the use of blood-based nucleic acid biomarkers to advance stroke diagnosis. We describe mRNA markers identified in genomic profiling of circulating leukocytes and then outline technological issues involved in the application of these results. We then describe the novel point-of-care technology that is in development for the rapid detection of multiple mRNA molecules in circulating leukocytes.

Immunohistochemical investigation of S100 and NSE in cases of traumatic brain injury and its application for survival time determination

The availability of markers able to provide insight into protein changes in the central nervous system after fatal traumatic brain injury (TBI) is limited. The present study reports on the semi-quantitative assessments of the immunopositive neuroglial cells (both astrocytes and oligodendrocytes) and neurons for S100 protein (S100), as well as neuronal specific enolase (NSE), in the cerebral cortex, hippocampus, and cerebellum with regard to survival time and cause of death. Brain tissues of 47 autopsy cases with TBI (survival times ranged between several minutes and 34 d) and 10 age- and gender-matched controls (natural deaths) were examined. TBI cases were grouped according to their survival time in acute death after brain injury (ABI, n = 25), subacute death after brain injury (SBI, n = 18) and delayed death after brain injury (DBI, n = 4). There were no significant changes in the percentages of S100-stained astrocytes between TBI and control cases. The percentages of S100-positive oligodendrocytes in the pericontusional zone (PCZ) in cases with SBI were significantly lower than in controls (p < 0.05) and in the ABI group (p < 0.05). In the hippocampus, S100-positive oligodendrocytes were significantly lower in cases with ABI and SBI (both, p < 0.05), compared with controls. It is of particular interest that there were also S100-positive neurons in the PCZ and hippocampus in TBI cases after more than 2 h survival but not in ABI cases or controls. The percentages of NSE-positive neurons in the hippocampus were likewise significantly lower in cases with ABI, compared with controls (p < 0.05) but increased in cases with SBI in PCZ (p < 0.05). In conclusion, the present findings emphasize that S100 and NSE-immunopositivity might be useful for detecting the cause and process of death due to TBI. Further, S100-positivity in neurons may be helpful to estimate the survival time of fatal injuries in legal medicine.

Intricacies of redoxome function demonstrated with a simple in vitro chemiluminescence method, with special reference to vitamin B12 as antioxidant

The homeostatic control of the redox system (the redoxome) in mammalian cells depends upon a large number of interacting molecules, which tend to buffer the electronegativity of cells against oxidants or reductants. Some of these components kill – at high concentration – microbes and by-stander normal cells, elaborated by professional phagocytes. We examined whether a simple, in vitro chemiluminescence set-up, utilizing redox components from human polymorphonuclear neutrophils (PMN) and red blood cells (RBC), could clarify some unexplained workings of the redoxome. PMN or purified myeloperoxidase (MPO) triggers formation of reactive oxygen species (ROS), quantified by light emission from oxidized luminol. Both PMN and RBC can generate abundant amounts of ROS, necessitating the presence of a high-capacity redoxome to keep the cellular electronegativity within physiological limits. We obtained proof-of-principle evidence that our assay could assess redox effects, but also demonstrated the intricacies of redox reactions. Simple dose–responses were found, as for the PMN proteins S100A9 (A9) and S100A8 (A8), and the system also revealed the reducing capacity of vitamin B12 (Cbl) and lutein. However, increased concentrations of oxidants in the assay mixture could decrease the chemiluminescence. Even more remarkable, A9 and NaOCl together stimulated the MPO response, but alone they inhibited MPO chemiluminescence. Biphasic responses were also recorded for some dose–response set-ups and are tentatively explained by a ‘balance hypothesis’ for the redoxome.

Cross-talk between neurons and astrocytes in response to bilirubin: adverse secondary impacts

Previous studies using monotypic nerve cell cultures have shown that bilirubin-induced neurological dysfunction (BIND) involves apoptosis and necrosis-like cell death, following neuritic atrophy and astrocyte activation,and that glycoursodeoxycholic acid (GUDCA) has therapeutic efficacy against BIND. Cross-talk between neurons and astrocytes may protect or aggravate neurotoxicity by unconjugated bilirubin (UCB). In a previous work we have shown that bidirectional signaling during astrocyte-neuron recognition attenuates neuronal damage by UCB. Here, we investigated whether the establishment of neuron-astrocyte homeostasis prior to cell exposure to UCB was instead associated with a lower resistance of neurons to UCB toxicity, and if the pro-survival properties of GUDCA were replicated in that experimental model. We have introduced a 24 h adaptation period for neuron-glia communication prior to the 48 h treatment with UCB. In such conditions, UCB induced glial activation, which aggravated neuronal damage, comprising increased apoptosis,cell demise and neuritic atrophy, which were completely prevented in the presence of GUDCA. Neuronal multidrug resistance-associated protein 1 expression and tumor necrosis factor-a secretion, although unchanged by UCB, increased in the presence of astrocytes. The rise in S100B and nitric oxide in the co-cultures medium may have contributed to UCB neurotoxicity. Since the levels of these diffusible molecules did not change by GUDCA we may assume that they are not directly involved in its beneficial effects. Data indicate that astrocytes, in an indirect neuron-astrocyte co-culture model and after homeostatic setting regulation of the system, are critically influencing neurodegeneration by UCB, and support GUDCA for the prevention of BIND.

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.

Further evidence for the neuroprotective role of oleanolic acid in a model of focal brain hypoxia in rats

Ischemic brain injury is a dynamic process involving oxidative stress, inflammation, cell death and the activation of endogenous adaptive and regenerative mechanisms depending on the activation of transcription factors such as hypoxia-inducible factor 1-alpha. Accordingly, we have previously described a new focal hypoxia model by direct intracerebral cobalt chloride injection. In turn, oleanolic acid, a plant-derived triterpenoid, has been extensively used in Asian countries for its anti-inflammatory and anti-tumor properties. A variety of novel pharmacological effects have been attributed to this triterpenoid, including beneficial effects on neurodegenerative disorders--including experimental autoimmune encephalomyelitis--due to its immunomodulatory activities at systemic level, as well as within the central nervous system. In this context, we hypothesize that this triterpenoid may be capable of exerting neuroprotective effects in ischemic brain, suppressing glial activities that contribute to neurotoxicity while promoting those that support neuronal survival. In order to test this hypothesis, we used the intraperitoneal administration of oleanoic acid in adult rats for seven days previous to focal cortical hypoxia induced by cobalt chloride brain injection. We analyzed the neuroprotective effect of oleanoic acid from a morphological point of view, focusing on neuronal survival and glial reaction.

Astrocytic and microglial response in experimentally induced diabetic rat brain

Diabetes Mellitus is associated with increased risk of cognitive and behavioural disorders with hitherto undeciphered role of glia. Glia as majority population in brain serve several vital functions, thus require pertinent revelation to further explicate the mechanisms affecting the brain function following diabetes. In this study we have evaluated glial changes in terms of phenotypic switching, proliferation and expression of activation cell surface markers and associated cellular degeneration in hippocampus following STZ-induced diabetes and caused cognitive impairments. Experimental diabetes was induced in Wistar rats by a single dose of STZ (45 mg/kg body weight; intraperitoneally) and changes were studied in 2nd, 4th and 6th week post diabetes confirmation using Barnes maze and T-maze test, immunohistochemistry and image analysis. An increase in GFAP expression sequentially from 2nd to 6th weeks of diabetes was analogous with the phenotypic changes and increased astrocyte number. Elevated level of S100β with defined stellate morphology further confirmed the astrocytosis following diabetes. Enhanced level of Iba-1 and MHC-II revealed the corroborated microglial activation and proliferation following diabetes, which was unresolved till date. Increased caspase-3 activity induced profound cell death upto 6th weeks post diabetes confirmation. Such caspase 3 mediated cellular damage with a concomitant activation of the astrocytes and microglia suggests that diabetes linked cell death activates the astrocytes and microglia in hippocampus which further underpin the progression and severity of brain disorders resulting in cognitive and behavioural impairments.

Role of astroglia in Down's syndrome revealed by patient-derived human-induced pluripotent stem cells

Down's syndrome (DS), caused by trisomy of human chromosome 21, is the most common genetic cause of intellectual disability. Here we use induced pluripotent stem cells (iPSCs) derived from DS patients to identify a role for astrocytes in DS pathogenesis. DS astroglia exhibit higher levels of reactive oxygen species and lower levels of synaptogenic molecules. Astrocyte-conditioned medium collected from DS astroglia causes toxicity to neurons, and fails to promote neuronal ion channel maturation and synapse formation. Transplantation studies show that DS astroglia do not promote neurogenesis of endogenous neural stem cells in vivo. We also observed abnormal gene expression profiles from DS astroglia. Finally, we show that the FDA-approved antibiotic drug, minocycline, partially corrects the pathological phenotypes of DS astroglia by specifically modulating the expression of S100B, GFAP, inducible nitric oxide synthase, and thrombospondins 1 and 2 in DS astroglia. Our studies shed light on the pathogenesis and possible treatment of DS by targeting astrocytes with a clinically available drug.

Apolipoprotein E, amyloid-beta, and neuroinflammation in Alzheimer's disease

Alzheimer's disease (AD) is characterized by the accumulation and deposition of amyloid-beta (Aβ) peptides in the brain. Neuroinflammation occurs in the AD brain and plays a critical role in the neurodegenerative pathology. Particularly, Aβ evokes an inflammatory response that leads to synaptic dysfunction, neuronal death, and neurodegeneration. Apolipoprotein E (ApoE) proteins are involved in cholesterol transport, Aβ binding and clearance, and synaptic functions in the brain. The ApoE4 isoform is a key risk factor for AD, while the ApoE2 isoform has a neuroprotective effect. However, studies have reached different conclusions about the roles of the isoforms; some show that both ApoE3 and ApoE4 have anti-inflammatory effects, while others show that ApoE4 causes a predisposition to inflammation or promotes an inflammatory response following lipopolysaccharide treatment. These discrepancies may result from the differences in models, cell types, experimental conditions, and inflammatory stimuli used. Further, little was known about the role of ApoE isoforms in the Aβ-induced inflammatory response and in the neuroinflammation of AD. Our recent work showed that ApoE isoforms differentially regulate and modify the Aβ-induced inflammatory response in neural cells, with ApoE2 suppressing and ApoE4 promoting the response. In this article, we review the roles, mechanisms, and interrelations among Aβ, ApoE, and neuroinflammation in AD.

Genetic analysis of the S100B gene in Chinese patients with Parkinson disease

There is growing evidence that genetic abnormalities play an important role in the pathogenesis of Parkinson disease (PD). At least 18 genetic loci and 13 disease-related genes for parkinsonism have been identified. The S100 calcium-binding beta (S100B), which is expressed and secreted by astrocytes, has been found to be associated with PD. To evaluate whether the S100B variants are related to PD in Chinese Han population, we conducted genetic examination of the S100B gene in 502 PD patients from Mainland China. We did identify two known variants c.279+4T>C (rs187503470) and c.99C>G (p.Leu33Leu, rs1051169) in our patients. Neither of these two variants is predicted to change amino acid or splice site, indicating that they are not pathogenic mutations. Our results suggest that mutations in the coding region or intron/exon boundaries of the S100B gene play little or no role in the development of PD in Chinese population.

Functions of S100 proteins

The S100 protein family consists of 24 members functionally distributed into three main subgroups: those that only exert intracellular regulatory effects, those with intracellular and extracellular functions and those which mainly exert extracellular regulatory effects. S100 proteins are only expressed in vertebrates and show cell-specific expression patterns. In some instances, a particular S100 protein can be induced in pathological circumstances in a cell type that does not express it in normal physiological conditions. Within cells, S100 proteins are involved in aspects of regulation of proliferation, differentiation, apoptosis, Ca2+ homeostasis, energy metabolism, inflammation and migration/invasion through interactions with a variety of target proteins including enzymes, cytoskeletal subunits, receptors, transcription factors and nucleic acids. Some S100 proteins are secreted or released and regulate cell functions in an autocrine and paracrine manner via activation of surface receptors (e.g. the receptor for advanced glycation end-products and toll-like receptor 4), G-protein-coupled receptors, scavenger receptors, or heparan sulfate proteoglycans and N-glycans. Extracellular S100A4 and S100B also interact with epidermal growth factor and basic fibroblast growth factor, respectively, thereby enhancing the activity of the corresponding receptors. Thus, extracellular S100 proteins exert regulatory activities on monocytes/macrophages/microglia, neutrophils, lymphocytes, mast cells, articular chondrocytes, endothelial and vascular smooth muscle cells, neurons, astrocytes, Schwann cells, epithelial cells, myoblasts and cardiomyocytes, thereby participating in innate and adaptive immune responses, cell migration and chemotaxis, tissue development and repair, and leukocyte and tumor cell invasion.

S100B protein as a possible participant in the brain metastasis of NSCLC

Brain metastasis is a frequent occurrence in lung cancer, especially non-small cell lung cancer (NSCLC), the prognosis for NSCLC with brain metastasis is very poor. Our previous study found high S100B expression in the brain-specific metastatic NSCLC line PC14/B, suggested S100B is closely correlated with brain metastasis in NSCLC. However, the details have not yet been revealed. The aim of this study was to investigate the correlation between S100B and brain metastasis in NSCLC and to study the effects of S100B on non-brain metastatic NSCLC line PC14. We investigated serum S100B levels in 30 newly diagnosed NSCLC patients (15 with brain metastasis and 15 without brain metastasis) using enzyme-linked immunosorbent assay. Results showed that serum S100B levels were significant higher in NSCLC patients with brain metastasis compared to those without brain metastasis (P<0.01). We constructed the full-length S100B expression vector and transfected into PC14 cells. MTT and flow cytometric analysis showed that S100B transfection promoted cell proliferation and inhibited cell apoptosis (P<0.05). Transwell migration and invasion assays indicated that S100B transfection promoted cell invasion and cell migration compared to control cells transfected with empty vector alone (P<0.01). These results suggested that S100B could be involved in the development of brain metastasis in NSCLC.

Intraperitoneal treatment with S100B enhances hippocampal neurogenesis in juvenile mice and after experimental brain injury

BACKGROUND

Neurogenesis is documented in adult mammals including humans, is promoted by neurotrophic factors, and constitutes an innate repair mechanism following brain injury. The glial neurotrophic protein S100B is released following various types of brain injuries, enhances hippocampal neurogenesis and improves cognitive function following brain injury in rats when applied intrathecally. The present study was designed to elucidate whether the beneficial effect of S100B on injury-induced neurogenesis can be confirmed in mice when applied intraperitoneally (i.p.), and whether this effect is dose-dependent.

METHODS

Male juvenile mice were subjected to a unilateral parietal cryolesion or sham injury, and treated with S100B at 20nM, 200nM or vehicle i.p. once daily. Hippocampal progenitor cell proliferation was quantified following labelling with bromo-deoxyuridine (BrdU, 50 mg/KG i.p.) in the germinative area of the dentate gyrus, the subgranular zone (SGZ), on day 4 as well as on cell survival and migration to the granular cell layer (GCL) on day 28. Progenitor cell differentiation was assessed following colabelling with the glial marker GFAP and the neuronal marker NeuN.

RESULTS

S100B enhanced significantly the early progenitor cell proliferation in the SGZ as well as cell survival and migration to the GCL, and promoted neuronal differentiation. While these effects were predominately dose-dependent, 200nM S100B failed to enhance the proliferation in the SGZ on day 4 post-injury.

CONCLUSION

We conclude that S100B participates in hippocampal neurogenesis after injury at lower nanomolar concentrations. Therefore S100B may serve as a potential adjunct treatment to promote neuroregeneration following brain damage.

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.

Serum S100B protein: a useful marker in obstructive sleep apnea syndrome

BACKGROUND AND PURPOSE

We aimed to underline the importance of serum S100B protein as a useful biochemical marker in patients with obstructive sleep apnea syndrome (OSAS).

MATERIAL AND METHODS

Forty-three newly diagnosed patients with OSAS (median apnea-hypopnea index [AHI, events/ hour]: 37.5 [range 11.3-137]) and 25 subjects with AHI < 5 (median AHI: 4.4 [range 0.7-4.8]) were included in the study. Serum S100B protein level was tested in serum samples taken after polysomnography in both groups and the difference between OSAS patients and the control group regarding that level was assessed. In addition, the association of S100B protein serum level with age, body mass index, AHI, mean O2 saturation percentage during sleep, minimum O2 saturation value (%) at the end of the apneas, and the time spent at an O2 saturation less than 90% were analyzed in the OSAS patient group.

RESULTS

Median serum S100B protein level was 133.7 pg/ mL (range 20.97-230.70 pg/mL) in patients with OSAS and 16.1 pg/mL (range 10.1-22.9 pg/mL) in the control group (p < 0.005). Serum S100B protein level did not correlate with any studied variable (p > 0.05 for each correlation coefficient).

CONCLUSIONS

Serum S100B protein level is increased in patients with OSAS and may be a useful biochemical marker in those patients.

Tetrandrine ameliorates cognitive impairment via inhibiting astrocyte-derived S100B activation in a rat model of chronic cerebral hypoperfusion

OBJECTIVES

To investigate the effects of tetrandrine (Tet) on cognitive impairment induced by chronic cerebral hypoperfusion and its potential anti-inflammatory mechanism by modulating the expression of S100B, interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), and inducible nitric oxide synthase (iNOS).

METHODS

Chronic cerebral hypoperfusion was induced by ligation of the bilateral common carotid arteries for 8 weeks. Rats were treated with Tet (10 mg/kg or 30 mg/kg) intraperitoneally every 3 days for 4 weeks. Cognitive function of rats was evaluated by the Morris water maze. Hematoxylin eosin (H & E) and Nissl staining were used to observe neuronal damage in the hippocampal CA1 region. Immunofluorescence, quantitative real-time polymerase chain reaction (QT-PCR), and western blot were performed to measure S100B, IL-1 beta, TNF-alpha, and iNOS levels in the CA1 region of chronic cerebral hypoperfusion rats.

RESULTS

The Tet-treated group significantly decreased the escape latency of chronic cerebral hypoperfusion rats in finding the hidden platform (P <0.05). Compared with the 2-VO (two-vessel occlusion) group, more neurons with regular morphology and/or Nissl bodies in the hippocampus were observed in the Tet-treated group, suggesting attenuated neuronal damage and degeneration. Additionally, S100B, IL-1 beta, TNF-alpha, and iNOS levels were significantly (P <0.05) decreased in the CA1 region of the chronic cerebral hypoperfusion affected rats treated with Tet.

CONCLUSION

Our results found that Tet could improve cognitive impairment in the chronic cerebral hypoperfusion rats. Tetrandrine may be a novel and promising candidate for future treatment and/or prevention of chronic cerebral hypoperfusion via inhibiting S100B activation and decreasing the expression of IL-1 beta, TNF-alpha, and iNOS in the hippocampal CA1 region.

S100B is increased in Parkinson's disease and ablation protects against MPTP-induced toxicity through the RAGE and TNF-α pathway

Parkinson’s disease is a neurodegenerative disorder that can, at least partly, be mimicked by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. S100B is a calcium-binding protein expressed in, and secreted by, astrocytes. There is increasing evidence that S100B acts as a cytokine or damage-associated molecular pattern protein not only in inflammatory but also in neurodegenerative diseases. In this study, we show that S100B protein levels were higher in post-mortem substantia nigra of patients with Parkinson’s disease compared with control tissue, and cerebrospinal fluid S100B levels were higher in a large cohort of patients with Parkinson’s disease compared with controls. Correspondingly, mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine showed upregulated S100B messenger RNA and protein levels. In turn, ablation of S100B resulted in neuroprotection, reduced microgliosis and reduced expression of both the receptor for advanced glycation endproducts and tumour necrosis factor-α. Our results demonstrate a role of S100B in the pathophysiology of Parkinson’s disease. Targeting S100B may emerge as a potential treatment strategy in this disorder.

Marked increase of the astrocytic marker S100B in the cerebrospinal fluid of HIV-infected patients on LPV/r-monotherapy

OBJECTIVE

To determine changes of cerebrospinal fluid (CSF) biomarkers of patients on monotherapy with lopinavir/ritonavir.

DESIGN

The Monotherapy Switzerland/Thailand study (MOST) trial compared monotherapy with ritonavir-boosted lopinavir with continued therapy. The trial was prematurely stopped due to virological failure in six patients on monotherapy. It, thus, offers a unique opportunity to assess brain markers in the early stage of HIV virological escape.

METHODS

: Sixty-five CSF samples (34 on continued therapy and 31 on monotherapy) from 49 HIV-positive patients enrolled in MOST. Using enzyme-linked immunosorbent assay, we determined the CSF concentration of S100B (astrocytosis), neopterin (inflammation), total Tau (tTau), phosphorylated Tau (pTau), and amyloid-β 1-42 (Aβ), the latter three indicating neuronal damage. Controls were CSF samples of 29 HIV-negative patients with Alzheimer dementia.

RESULTS

In the CSF of monotherapy, concentrations of S100B and neopterin were significantly higher than in continued therapy (P = 0.006 and P = 0.013, respectively) and Alzheimer dementia patients (P < 0.0001 and P = 0.0005, respectively). In Alzheimer dementia, concentration of Aβ was lower than in monotherapy (P = 0.005) and continued therapy (P = 0.016) and concentrations of tTau were higher than in monotherapy (P = 0.019) and continued therapy (P = 0.001). There was no difference in pTau among the three groups. After removal of the 16 CSF with detectable viral load in the blood and/or CSF, only S100B remained significantly higher in monotherapy than in the two other groups.

CONCLUSION

Despite full viral load-suppression in blood and CSF, antiretroviral monotherapy with lopinavir/ritonavir can raise CSF levels of S100B, suggesting astrocytic damage.

Time course of serum S100B protein and neuron-specific enolase levels of a single dose of chlorpyrifos in rats

Organophosphate (OP) compounds are a large class of chemicals, many of which are used as pesticides. It is suggested that OPs specifically affect glia and neurons. Effects of acute exposure to chlorpyrifos (CPF), which is a common organophosphorus pesticide used worldwide, on neuron-specific enolase (NSE) and S100B levels in rat blood during 7 days were assessed. Rats were evaluated either before (0 hr) or 2, 12, 24, 48 and 168 hr (7 days) after injection of CPF (279 mg/kg, s.c.) or vehicle (peanut oil, 2 ml/kg, s.c.) for clinical signs of toxicity. Immediately after the evaluation of toxicity, blood samples were taken for biochemical assays. CPF administration produced decreases in body-weight and temperature, which were observed for first time at 12 hr after CPF administration and continued for 168 hr (p < 0.05-0.001). Serum S100B and NSE levels were acutely increased 2 hr after CPF administration and remained high at 12 hr (p < 0.01-0.001). NSE and S100B levels were not different in either CPF or vehicle groups at following time points. Serum butyrylcholinesterase (EC 3.1.1.8; BuChE) activity was dramatically reduced at 2 hr after CPF and remained low at each time points during 7 days (p < 0.01-0.001). Our results suggest that the usefulness of serum levels of these glia- and neuron-specific marker proteins in assessing OP toxicity, specifically CPF-induced toxicity.

Asymmetric production of nitric oxide in mouse primary cortical mixed glial cell cultures treated with lipopolysaccharide

Activated glial cells produce many toxic molecules, including cytokines and nitric oxide (NO). There is evidence that excess NO production plays a key role in neuronal cell death. Previous research has demonstrated that cortical glial cells from the left and right cortices of the brain secrete cytokines asymmetrically. However, no evidence to date exists about whether glial cell-produced NO is produced asymmetrically as well. The results of this study show that NO production and inducible NO synthase gene expression are both significantly higher in the right hemisphere-derived mixed glial cell compared with cultures derived from the left.

Neurological diseases as primary gliopathies: a reassessment of neurocentrism

Diseases of the human brain are almost universally attributed to malfunction or loss of nerve cells. However, a considerable amount of work has, during the last decade, expanded our view on the role of astrocytes in CNS (central nervous system), and this analysis suggests that astrocytes contribute to both initiation and propagation of many (if not all) neurological diseases. Astrocytes provide metabolic and trophic support to neurons and oligodendrocytes. Here, we shall endeavour a broad overviewing of the progress in the field and forward the idea that loss of homoeostatic astroglial function leads to an acute loss of neurons in the setting of acute insults such as ischaemia, whereas more subtle dysfunction of astrocytes over periods of months to years contributes to epilepsy and to progressive loss of neurons in neurodegenerative diseases. The majority of therapeutic drugs currently in clinical use target neuronal receptors, channels or transporters. Future therapeutic efforts may benefit by a stronger focus on the supportive homoeostatic functions of astrocytes.

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.

S100 proteins in cartilage: role in arthritis

S100 proteins are low molecular weight calcium binding proteins expressed in vertebrates. The family constitutes 21 known members that are expressed in several tissues and cell types and play a major role in various cellular functions. Uniquely, members of the S100 family have both intracellular and extracellular functions. Several members of the S100 family (S100A1, S100A2, S100A4, S1008, S100A9, S100A11, and S100B) have been identified in human articular cartilage, and their expression is upregulated in diseased tissue. These S100 proteins elicit a catabolic signaling pathway via receptor for advanced glycation end products (RAGE) in cartilage and may promote progression of arthritis. This review summarizes our current understanding of the role of S100 proteins in cartilage biology and in the development of arthritis.

Serum S100B levels in children with simple febrile seizures

PURPOSE

Recent studies have found that S100B is a useful marker for astroglial activation seen in various neurologic disorders. The purpose of this study was to evaluate whether simple febrile seizures (SFS) was associated with an elevation in serum S100B levels.

METHODS

In this study the samples consisted of 39 patients with SFS ranging from 6 to 36 months of age, and age-matched and sex-matched controls including 30 patients with fever and 30 healthy subjects. Two serum samples were obtained for S100B from the study group at 0-1h and 6-24h following seizure. Serum samples were drawn once in the control group. The serum samples were then analyzed using ELISA.

RESULTS

In the study group, the mean values of the serum S100B concentrations at 0-1h and 6-24h were 32.6±7.8pg/ml and 32.1±5.8pg/ml, respectively, while the concentrations were 32.1±8.8pg/ml and 29.5±7.8pg/ml in the control groups. No significant differences were detected in serum S100B levels at 0-1h or 6-24h in the study when compared to the control groups.

CONCLUSIONS

These results suggest that SFS do not raise serum S100B concentration above the normal range.

Complete transglutaminase 2 ablation results in reduced stroke volumes and astrocytes that exhibit increased survival in response to ischemia

Transglutaminase 2 (TG2) is a very multifunctional protein that is ubiquitously expressed in the body. It is a Ca(2+)-dependent transamidating enzyme, a GTPase, as well as a scaffolding protein. TG2 is the predominant form of transglutaminase expressed in the mammalian nervous system. Previously, it was shown that TG2 can affect both cell death and cell survival mechanisms depending on the cell type and the stressor. In the case of ischemic stress, TG2 was previously shown to play a protective role in the models used. For example in hTG2 transgenic mice, where TG2 is overexpressed only in neurons, middle cerebral artery ligation (MCAL) resulted in smaller infarct volumes compared to wild type mice. In this study TG2 knock out mice were used to determine how endogenous TG2 affected stroke volumes. Intriguingly, infarct volumes in TG2 knock out mice were significantly smaller compared to wild type mice. As expected, primary neurons isolated from TG2 knock out mice showed decreased viability in response to oxygen-glucose deprivation. However, primary astrocytes that were isolated from TG2 knock out mice were resistant to oxygen-glucose deprivation in situ. Both wild type and knock out neurons were protected against oxygen glucose deprivation when they were co-cultured with astrocytes from TG2 knockout mice. Therefore, the decreased stroke volumes observed in TG2 knock out mice after MCAL, can be correlated with the protective effects of TG2 knock out in astrocytes in response to oxygen glucose deprivation in situ. These findings suggest that neuron-astrocyte crosstalk plays a significant role in mediating ischemic cell death and that TG2 differentially impacts cell survival depending on cell context.

Increased circulating leukocyte numbers and altered macrophage phenotype correlate with the altered immune response to brain injury in metallothionein (MT)-I/II null mutant mice

BACKGROUND

Metallothionein-I and -II (MT-I/II) is produced by reactive astrocytes in the injured brain and has been shown to have neuroprotective effects. The neuroprotective effects of MT-I/II can be replicated in vitro which suggests that MT-I/II may act directly on injured neurons. However, MT-I/II is also known to modulate the immune system and inflammatory processes mediated by the immune system can exacerbate brain injury. The present study tests the hypothesis that MT-I/II may have an indirect neuroprotective action via modulation of the immune system.

METHODS

Wild type and MT-I/II(-/-) mice were administered cryolesion brain injury and the progression of brain injury was compared by immunohistochemistry and quantitative reverse-transcriptase PCR. The levels of circulating leukocytes in the two strains were compared by flow cytometry and plasma cytokines were assayed by immunoassay.

RESULTS

Comparison of MT-I/II(-/-) mice with wild type controls following cryolesion brain injury revealed that the MT-I/II(-/-) mice only showed increased rates of neuron death after 7 days post-injury (DPI). This coincided with increases in numbers of T cells in the injury site, increased IL-2 levels in plasma and increased circulating leukocyte numbers in MT-I/II(-/-) mice which were only significant at 7 DPI relative to wild type mice. Examination of mRNA for the marker of alternatively activated macrophages, Ym1, revealed a decreased expression level in circulating monocytes and brain of MT-I/II(-/-) mice that was independent of brain injury.

CONCLUSIONS

These results contribute to the evidence that MT-I/II(-/-) mice have altered immune system function and provide a new hypothesis that this alteration is partly responsible for the differences observed in MT-I/II(-/-) mice after brain injury relative to wild type mice.

Umbilical cord blood biomarkers of neurologic injury and the risk of cerebral palsy or infant death

To evaluate the association between cerebral palsy (CP) or infant death and putative cord blood biomarkers of neurologic injury, we performed a nested case-control secondary analysis of a multicenter randomized trial of magnesium sulfate (MgSO(4)) versus placebo to prevent CP or death among offspring of women with anticipated delivery from 24 to 31 weeks' gestation. Cases were infants who died by 1 year (n=25) or developed CP (n=16), and were matched 1:2 to a control group (n=82) that survived without developing CP. Umbilical cord sera concentrations of S100B, neuron-specific enolase (NSE) and the total soluble form of the receptor for advanced glycation end-products (sRAGE) were measured by ELISA in duplicates. Maternal characteristics were similar between the 2 groups. Cases were born at a lower gestational age (GA) and had lower birth weight compared with controls. There were no differences in concentrations of the three biomarkers and the composite outcome of CP or infant death. However, S100B was higher (median 847.3 vs. 495.7 pg/ml; P=0.03) in infants who had CP and total sRAGE was lower (median 1259.3 vs. 1813.1 pg/ml; P=0.02) in those who died compared with the control group. When corrected for delivery GA and treatment group, both differences lost statistical significance. In conclusion, cord blood S100B level may be associated with CP, but this association was not significant after controlling for GA and MgSO(4) treatment.

Phenotypically aberrant astrocytes that promote motoneuron damage in a model of inherited amyotrophic lateral sclerosis

Motoneuron loss and reactive astrocytosis are pathological hallmarks of amyotrophic lateral sclerosis (ALS), a paralytic neurodegenerative disease that can be triggered by mutations in Cu-Zn superoxide dismutase (SOD1). Dysfunctional astrocytes contribute to ALS pathogenesis, inducing motoneuron damage and accelerating disease progression. However, it is unknown whether ALS progression is associated with the appearance of a specific astrocytic phenotype with neurotoxic potential. Here, we report the isolation of astrocytes with aberrant phenotype (referred as "AbA cells") from primary spinal cord cultures of symptomatic rats expressing the SOD1(G93A) mutation. Isolation was based on AbA cells' marked proliferative capacity and lack of replicative senescence, which allowed oligoclonal cell expansion for 1 y. AbA cells displayed astrocytic markers including glial fibrillary acidic protein, S100β protein, glutamine synthase, and connexin 43 but lacked glutamate transporter 1 and the glial progenitor marker NG2 glycoprotein. Notably, AbA cells secreted soluble factors that induced motoneuron death with a 10-fold higher potency than neonatal SOD1(G93A) astrocytes. AbA-like aberrant astrocytes expressing S100β and connexin 43 but lacking NG2 were identified in nearby motoneurons, and their number increased sharply after disease onset. Thus, AbA cells appear to be an as-yet unknown astrocyte population arising during ALS progression with unprecedented proliferative and neurotoxic capacity and may be potential cellular targets for slowing ALS progression.

S100B and APP promote a gliocentric shift and impaired neurogenesis in Down syndrome neural progenitors

Down syndrome (DS) is a developmental disorder associated with mental retardation (MR) and early onset Alzheimer's disease (AD). These CNS phenotypes are attributed to ongoing neuronal degeneration due to constitutive overexpression of chromosome 21 (HSA21) genes. We have previously shown that HSA21 associated S100B contributes to oxidative stress and apoptosis in DS human neural progenitors (HNPs). Here we show that DS HNPs isolated from fetal frontal cortex demonstrate not only disturbances in redox states within the mitochondria and increased levels of progenitor cell death but also transition to more gliocentric progenitor phenotypes with a consequent reduction in neuronogenesis. HSA21 associated S100B and amyloid precursor protein (APP) levels are simultaneously increased within DS HNPs, their secretions are synergistically enhanced in a paracrine fashion, and overexpressions of these proteins disrupt mitochondrial membrane potentials and redox states. HNPs show greater susceptibility to these proteins as compared to neurons, leading to cell death. Ongoing inflammation through APP and S100B overexpression further promotes a gliocentric HNPs phenotype. Thus, the loss in neuronal numbers seen in DS is not merely due to increased HNPs cell death and neurodegeneration, but also a fundamental gliocentric shift in the progenitor pool that impairs neuronal production.