Search

Dopamine (DA) is a catecholamine neurotransmitter widely distributed in the central nervous system. It participates in various physiological functions, such as feeding, anxiety, fear, sleeping and arousal. The regulation of feeding is exceptionally complex, involving energy homeostasis and reward motivation. The reward system comprises the ventral tegmental area (VTA), nucleus accumbens (NAc), hypothalamus, and limbic system. This paper illustrates the detailed mechanisms of eight typical orexigenic and anorexic neuropeptides that regulate food intake through the reward system. According to recent literature, neuropeptides released from the hypothalamus and other brain regions regulate reward feeding predominantly through dopaminergic neurons projecting from the VTA to the NAc. In addition, their effect on the dopaminergic system is mediated by the prefrontal cortex, paraventricular thalamus, laterodorsal tegmental area, amygdala, and complex neural circuits. Research on neuropeptides involved in reward feeding can help identify more targets to treat diseases with metabolic disorders, such as obesity. [ABSTRACT FROM AUTHOR]

Neuroproteomics has become a ‘symbol’ or even a ‘sign’ for neuroscientists in the post-genomic era. During the last several decades, a number of proteomic approaches have been used widely to decipher the complexity of the brain, including the study of embryonic stages of human or non-human animal brain development. The use of proteomic techniques has allowed for great scientific advancements, including the quantitative analysis of proteomic data using 2D-DIGE, ICAT and iTRAQ. In addition, proteomic studies of the brain have expanded into fields such as subproteomics, synaptoproteomics, neural plasma membrane proteomics and even mitochondrial proteomics. The rapid progress that has been made in this field will not only increase the knowledge based on the neuroproteomics of the developing brain but also help to increase the understanding of human neurological diseases. This paper will focus on proteomic studies in the central nervous system and especially those conducted on the development of the brain in order to summarize the advances in this rapidly developing field. [ABSTRACT FROM AUTHOR]

Central nervous system (CNS) injuries are the most common cause of death and disability around the world. The blood-brain barrier (BBB) is located at the interface between the CNS and the surrounding environment, which protects the CNS from exogenous molecules, harmful agents or microorganisms in the blood. The disruption of BBB is a common feature of CNS injuries and participates in the pathological processes of secondary brain damage. Recently, a growing number of studies have indicated that non-coding RNAs (ncRNAs) play an important role in brain development and are involved in CNS injuries. In this review, we summarize the mechanisms of BBB breakdown after CNS injuries. We also discuss the effects of ncRNAs including long noncoding RNAs (lncRNAs), circular RNAs (circRNAs) and microRNAs (miRNAs) on BBB damage in CNS injuries such as ischemic stroke, traumatic brain injury (TBI), intracerebral hemorrhage (ICH) and subarachnoid hemorrhage (SAH). In addition, we clarify the pharmacotherapies that could regulate BBB function via ncRNAs in CNS injuries, as well as the challenges and perspectives of ncRNAs on modulation of BBB function. Hence, on the basis of these effects, ncRNAs may be developed as therapeutic agents to protect the BBB for CNS injury patients. [ABSTRACT FROM AUTHOR]

Determinations of plaminogen activator (PA) activity are usually performed in Triton X-100-treated tissue homogenates or crude membrane fractions. Such preparations usually involve a single Triton X-100 treatment. In the present paper we describe the pattern of variability of PA activity measured in different fractions obtained from the developing chick CNS by a repetitive procedure of Triton X-100 treatment and ultracentrifugation. To further characterize this PA activity we have also performed zymographic analyses during the embryonic development and the early postnatal life. Our results show that: a) a single Triton X-100 treatment does not completely extract the enzyme and this lead to an underestimation of the total PA activity; b) the PA activity is associated with the particulate component of the total tissue homogenate requiring its complete solubilization more drastic Triton X-100 treatments; c) better estimations of total and specific activities are obtained by using soluble fractions derived by ultracentrifugation from Triton X-100-treated membrane fractions; d) the developing chick optic lobe expresses only one kind of PA molecule along the entire development; e) the level of PA activity vary characteristically during the ontogeny and the early postnatal life indicating the existence of a developmentally regulated mechanism of PA expression. [ABSTRACT FROM AUTHOR]

Environmental pollution is a global threat and represents a strong risk factor for human health. It is estimated that pollution causes about 9 million premature deaths every year. Pollutants that can cross the blood–brain barrier and reach the central nervous system are of special concern, because of their potential to cause neurological and development disorders. Arsenic, lead and mercury are usually ranked as the top three in priority lists of regulatory agencies. Against xenobiotics, astrocytes are recognised as the first line of defence in the CNS, being involved in virtually all brain functions, contributing to homeostasis maintenance. Here, we discuss the current knowledge on the astroglial involvement in the neurotoxicity induced by these pollutants. Beginning by the main toxicokinetic characteristics, this review also highlights the several astrocytic mechanisms affected by these pollutants, involving redox system, neurotransmitter and glucose metabolism, and cytokine production/release, among others. Understanding how these alterations lead to neurological disturbances (including impaired memory, deficits in executive functions, and motor and visual disfunctions), by revisiting the current knowledge is essential for future research and development of therapies and prevention strategies. [ABSTRACT FROM AUTHOR]

Neurodegenerative diseases refer to a group of neurological disorders as a consequence of various destructive illnesses, that predominantly impact neurons in the central nervous system, resulting in impairments in certain brain functions. Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, and other neurodegenerative disorders represent a major risk to human health. In order to optimize structural and functional recovery, reconstructive methods integrate many approaches now, to address the complex and multivariate pathophysiology of neurodegenerative disorders. Stem cells, with their unique property of regeneration, offer new possibilities in regenerative and reconstructive medicine. Concurrently, there is an important role for natural products in controlling many health sufferings and they can delay or even prevent the onset of various diseases. In addition, due to their therapeutic properties, they have been used as neuroprotective agents to treat neurodegenerative disorders. After decades of intensive research, scientists made advances in treating these disorders so far, but current therapies are still not capable of preventing the illnesses from progressing. Therefore, in this review, we focused on a new perspective combining stem cells and natural products as an innovative therapy option in the management of neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Astrocytes act as "housekeeping cells" for maintaining cerebral homeostasis and play an important role in many disorders. Recent studies further highlight the contribution of autophagy to astrocytic functions, including astrogenesis, the astrocytic removal of neurotoxins or stressors, and astrocytic polarization. More importantly, genetic and pharmacological approaches have provided evidence that outlines the contributions of astrocytic autophagy to several brain disorders, including neurodegeneration, cerebral ischemia, and depression. In this study, we summarize the emerging role of autophagy in regulating astrocytic functions and discuss the contributions of astrocytic autophagy to different CNS disorders. [ABSTRACT FROM AUTHOR]

As innate immune cells of the central nervous system (CNS), microglia are involved in the physiological processes of the CNS, including neural development and maintenance of homeostasis, and in the occurrence and development of most CNS diseases. Lipoxygenases (LOXs) are a family of non-heme, iron-containing enzymes that generate lipid mediators that regulate cellular inflammation by catalyzing the oxidation of polyunsaturated fatty acids. Many previous studies have demonstrated the indispensable role of the LOX pathway in microglia-mediated neuroinflammation, especially the 5-LOX and 12/15-LOX pathways. Emerging evidence indicates that the LOX pathway is also implicated in physiological processes, such as synaptic pruning and synaptic phagocytosis mediated by microglia, and that deficiency can contribute to neurodevelopmental disorders. The present review summarizes the impact of the LOX pathway on microglia-related physiological and pathological processes in the CNS and describes the potential for inhibition of the LOX pathway as a future strategy for the treatment of CNS diseases. [ABSTRACT FROM AUTHOR]

Ergothioneine (ERGO) is a thiol contained in the food that exhibits an excellent antioxidant effect similar to that of glutathione. Although mammals lack a biosynthetic pathway for ERGO, the carnitine/organic cation transporter OCTN1/SLC22A4, which transports ERGO in vivo, is expressed throughout the body, and ERGO is distributed to various organs after oral intake. ERGO is a stable compound that remains in the body for a long time after ingestion. OCTN1 is also expressed in brain parenchymal cells, including neurons, and ERGO in the blood permeates the blood–brain barrier and is distributed to the brain, exhibiting a neuroprotective effect. Recently, the association between central nervous system (CNS) diseases and ERGO has become a research focus. ERGO concentrations in the blood components are lower in patients with cognitive impairment, Parkinson's disease, and frailty than in healthy subjects. ERGO exerts a protective effect against various neurotoxins and improves the symptoms of cognitive impairment, depression, and epilepsy in animal models. The promotion of neurogenesis and induction of neurotrophic factors, in addition to the antioxidant and anti-inflammatory effects, may be involved in the neuroprotective effect of ERGO. This review shows the association between ERGO and CNS diseases, discusses the possible biomarkers of peripheral ERGO in CNS diseases, and the possible preventive and improvement effects of ERGO on CNS diseases. [ABSTRACT FROM AUTHOR]

Glutamate is the predominant excitatory neurotransmitter in the mammalian central nervous system (CNS). A family of five Na+-dependent transporters maintain low levels of extracellular glutamate and shape excitatory signaling. Shortly after the research group of the person being honored in this special issue (Dr. Baruch Kanner) cloned one of these transporters, his group and several others showed that their activity can be acutely (within minutes to hours) regulated. Since this time, several different signals and post-translational modifications have been implicated in the regulation of these transporters. In this review, we will provide a brief introduction to the distribution and function of this family of glutamate transporters. This will be followed by a discussion of the signals that rapidly control the activity and/or localization of these transporters, including protein kinase C, ubiquitination, glutamate transporter substrates, nitrosylation, and palmitoylation. We also include the results of our attempts to define the role of palmitoylation in the regulation of GLT-1 in crude synaptosomes. In some cases, the mechanisms have been fairly well-defined, but in others, the mechanisms are not understood. In several cases, contradictory phenomena have been observed by more than one group; we describe these studies with the goal of identifying the opportunities for advancing the field. Abnormal glutamatergic signaling has been implicated in a wide variety of psychiatric and neurologic disorders. Although recent studies have begun to link regulation of glutamate transporters to the pathogenesis of these disorders, it will be difficult to determine how regulation influences signaling or pathophysiology of glutamate without a better understanding of the mechanisms involved. [ABSTRACT FROM AUTHOR]

Astrocytes are the primary homeostatic cells of the central nervous system, essential for normal neuronal development and function, metabolism and response to injury and inflammation. Here, we review postmortem studies examining changes in astrocytes in subjects diagnosed with the neuropsychiatric disorders schizophrenia (SCZ), major depressive disorder (MDD), and bipolar disorder (BPD). We discuss the astrocyte-related changes described in the brain in these disorders and the potential effects of psychotropic medication on these findings. Finally, we describe emerging tools that can be used to study the role of astrocytes in neuropsychiatric illness. [ABSTRACT FROM AUTHOR]

Interleukin-2 (IL-2) is a classical pro-inflammatory cytokine known to display neuroprotective roles in the central nervous system including the retina. In the present study, we investigate the molecular targets involved in the neurotrophic effect of IL-2 on retinal ganglion cells (RGC) after optic nerve axotomy. Analysis of retrograde labeling of RGC showed that common cell survival mediators, as Trk receptors, Src, PI3K, PKC, and intracellular calcium do not mediate the neurotrophic effect of IL-2 on RGC. No involvement of MAPK p38 was also observed. However, other MAPKs as MEK and JNK appear to be mediating this IL-2 effect. Our data also indicate that JAK2/3 are important intracellular proteins for the IL-2 effect. Interestingly, we demonstrate that the IL-2 effect depends on dopamine D1 receptors (D1R), the cAMP/PKA pathway, interleukin-10 (IL-10), and NF-κB, suggesting that RGC survival induced by IL-2 encompasses a molecular network of major complexity. In addition, treatment of retinal cells with recombinant IL-10 or 6-Cl-pb (D1R full agonist) was able to increase RGC survival similar to IL-2. Taken together, our results suggest that after optic nerve axotomy, the increase in RGC survival triggered by IL-2 is mediated by IL-10 and D1R along with the intracellular pathways of MAPKs, JAK/STAT, and cAMP/PKA. [ABSTRACT FROM AUTHOR]

Physical exercise is beneficial to the structural and functional recovery of post-ischemic stroke, but its molecular mechanism remains obscure. Herein, we aimed to explore the underlying mechanism of exercise-induced neuroprotection from the perspective of microRNAs (miRNAs). Adult male Sprague–Dawley (SD) rats were randomly distributed into 4 groups, i.e., the physical exercise group with the transient middle cerebral artery occlusion (tMCAO) surgery (PE-IS, n = 28); the physical exercise group without tMCAO surgery (PE, n = 6); the sedentary group with tMCAO surgery (Sed-IS, n = 28); and the sedentary group without tMCAO surgery (Sed, n = 6). Notably, rats in the PE-IS and PE groups were subjected to a running exercise for 28 days while rats in the Sed-IS and Sed groups received no exercise training. After long-term exercise, exosomal miRNAs of cerebrospinal fluid (CSF) were analyzed using high-throughput sequencing. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were employed for the differentially expressed miRNAs. Physical exercise improved the neurological function and attenuated the lesion expansion after stroke. In total, 41 differentially expressed miRNAs were screened for the GO and KEGG analysis. GO enriched terms were associated with the central nervous system, including cellular response to retinoic acid, vagus nerve morphogenesis, cellular response to hypoxia, dendritic cell chemotaxis, cell differentiation, and regulation of neuron death. Besides, these differentially expressed miRNAs were linked to the pathophysiological process of stroke, including axon guidance, NF-kappa B signaling pathway, thiamine metabolism, and MAPK signaling pathway according to KEGG analysis. In summary, exercise training significantly alleviated the neurological damage at both functional and structural levels. Moreover, the differentially expressed miRNAs regulating multiple signal pathways were potentially involved in the neuroprotective effects of physical exercise. Therefore, these miRNAs altered by physical exercise might represent the therapeutic strategy for cerebral ischemia. [ABSTRACT FROM AUTHOR]

The hormone hepcidin plays a central role in controlling iron homeostasis. Iron-mediated hepcidin synthesis is triggered via the BMP/SMAD pathway. At inflammation, mainly IL-6 pro-inflammatory cytokine mediates the regulation of hepcidin via the JAK/STAT signalling pathway. Microglial cells of the central nervous system are able to recognize a broad spectrum of pathogens via toll-like receptors and initiate inflammatory response. Although the regulation of hepcidin synthesis is well described in many tissues, little is known about the inflammation mediated hepcidin regulation in microglia. In this study, we investigated the pathways, which are involved in HAMP regulation in BV2 microglia due to inflammatory mediators and the possible relationships between the iron regulatory pathways. Our results showed that IL-6 produced by resting BV2 cells was crucial in maintaining the basal HAMP expression and hepcidin secretion. It was revealed that IL-6 neutralization decreased both STAT3 and SMAD1/5/9 phosphorylation suggesting that IL-6 proinflammatory cytokine is necessary to maintain SMAD1/5/9 activation. We revealed that IL-6 influences BMP6 and TMPRSS6 protein levels, moreover it modified TfR2 expression, as well. In this study, we revealed that BV2 microglia increased their hepcidin secretion upon IL-6 neutralization although the major regulatory pathways were inhibited. Based on our results it seems that both at inflammation and at normal condition the absence of IL-6 triggered HAMP transcription and hepcidin secretion via the NFκB pathway and possibly by the autocrine effect of TNFα cytokine on BV2 microglia. [ABSTRACT FROM AUTHOR]

Exposure to specific doses of hypoxia can trigger endogenous neuroprotective and neuroplastic mechanisms of the central nervous system. These molecular mechanisms, together referred to as hypoxic preconditioning (HPC), remain poorly understood. In the present study, we applied RNA sequencing and bioinformatics analyses to study HPC in a whole-body HPC mouse model. The preconditioned (H4) and control (H0) groups showed 605 differentially expressed genes (DEGs), of which 263 were upregulated and 342 were downregulated. Gene Ontology enrichment analysis indicated that these DEGs were enriched in several biological processes, including metabolic stress and angiogenesis. The Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that the FOXO and Notch signaling pathways were involved in hypoxic tolerance and protection during HPC. Furthermore, 117 differential alternative splicing events (DASEs) were identified, with exon skipping being the dominant one (48.51%). Repeated exposure to systemic hypoxia promoted skipping of exon 7 in Edrf1 and exon 9 or 13 in Lrrc45. This study expands the understanding of the endogenous protective mechanisms of HPC and the DASEs that occur during HPC. [ABSTRACT FROM AUTHOR]

Methylglyoxal (MG) is a by-product of glycolysis. In pathological conditions, particularly diabetes mellitus, this molecule is unbalanced, causing widespread protein glycation. In addition to protein glycation, other effects resulting from high levels of MG in the central nervous system may involve the direct modulation of GABAergic and glutamatergic neurotransmission, with evidence suggesting that the effects of MG may be related to behavioral changes and glial dysfunction. In order to evaluate the direct influence of MG on behavioral and biochemical parameters, we used a high intracerebroventricular final concentration (3 μM/μL) to assess acute effects on memory and locomotor behavior in rats, as well as the underlying alterations in glutamatergic and astroglial parameters. MG induced, 12 h after injection, a decrease in locomotor activity in the Open field and anxiolytic effects in rats submitted to elevated plus-maze. Subsequently, 36 h after surgery, MG injection also induced cognitive impairment in both short and long-term memory, as evaluated by novel object recognition task, and in short-term spatial memory, as evaluated by the Y-maze test. In addition, hippocampal glutamate uptake decreased and glutamine synthetase activity and glutathione levels diminished during seventy-two hours after infusion of MG. Interestingly, the astrocytic protein, S100B, was increased in the cerebrospinal fluid, accompanied by decreased hippocampal S100B mRNA expression, without any change in protein content. Taken together, these results may improve our understanding of how this product of glucose metabolism can induce the brain dysfunction observed in diabetic patients, as well as in other neurodegenerative conditions, and further defines the role of astrocytes in disease and therapeutics. [ABSTRACT FROM AUTHOR]

Increasing evidence has revealed that neuroinflammation plays a pivotal role in axonal injures. Nucleotide oligomerization domain (NOD)-like receptor protein (NLRP3) inflammasome is reported to be widely involved with the pathology of central nervous system disorders. But the role of NLRP3 in diffuse axonal injury (DAI) are rarely reported. The purpose of this study was to investigate the expression of NLRP3 after diffuse axonal injury and the role of NLRP3 in axonal injures. The lateral head rotation device was used to establish DAI model of rats. Immunohistochemical staining for β-amyloid precursor protein and Bielschowsky silver staining were used to assess axonal injures and axonal loss. Terminal Deoxynucleotidyl Transferase-Mediated Digoxigenin-dUTP-Biotin Nick-End Labelling Assay was used to detect cell apoptosis. Brain water content was used to assess cerebral edema and the modified Neurologic Severity Score was used to assess the neurological deficits. Components of NLRP3 inflammasome, such as NLRP3, apoptosis-associated speck-like (ASC) adapter protein and caspase-1, and pro-inflammatory cytokines, for example IL-18 and IL-1β, were over-expressed in early stages of DAI. MCC950, a selective small-molecule inhibitor of NLRP3 inflammasome, inhibited the over-expression of NLRP3 inflammasome and pro-inflammatory cytokines after DAI. MCC950 alleviated axonal injures and cell apoptosis. MCC950 also decreased brain water content and alleviated neurologic deficits 1 day and 3 days after DAI but not 7 days after DAI. These results suggest that MCC950 treatment in the early stages of DAI has a time limiting effect in preventing from axonal injuries and neurological deficits, and that NLRP3 inflammasome plays an important role in axonal injures and may be a potential candidate for axonal injures following DAI. [ABSTRACT FROM AUTHOR]

Thiamine deficiency (TD) produces severe neurodegenerative lesions. Studies have suggested that primary neurodegenerative events are associated with both oxidative stress and inflammation. Very little is known about the downstream effects on intracellular signaling pathways involved in neuronal death. The primary aim of this work was to evaluate the modulation of p38MAPK and the expression of heme oxygenase 1 (HO-1) in the central nervous system (CNS). Behavioral, metabolic, and morphological parameters were assessed. Mice were separated into six groups: control (Cont), TD with pyrithiamine (Ptd), TD with pyrithiamine and Trolox (Ptd + Tr), TD with pyrithiamine and dimethyl sulfoxide (Ptd + Dmso), Trolox (Tr) and DMSO (Dmso) control groups and treated for 9 days. Control groups received standard feed (AIN-93M), while TD groups received thiamine deficient feed (AIN-93DT). All the groups were subjected to behavioral tests, and CNS samples were collected for cell viability, histopathology and western blot analyses. The Ptd group showed a reduction in weight gain and feed intake, as well as a reduction in locomotor, grooming, and motor coordination activities. Also, Ptd group showed a robust increase in p38MAPK phosphorylation and mild HO-1 expression in the cerebral cortex and thalamus. The Ptd group showed a decreased cell viability, hemorrhage, spongiosis, and astrocytic swelling in the thalamus. Groups treated with Trolox and DMSO displayed diminished p38MAPK phosphorylation in both the structures, as well as attenuated thalamic lesions and behavioral activities. These data suggest that p38MAPK and HO-1 are involved in the TD-induced neurodegeneration in vivo, possibly modulated by oxidative stress and neuroinflammation. [ABSTRACT FROM AUTHOR]

The cerebellum is a brain region that undergoes extremely dynamic growth during perinatal and postnatal development which is regulated by the proper interaction between glial cells and neurons with a complex concert of growth factors, chemokines, cytokines, neurotransmitters and transcriptions factors. The relevance of cerebellar functions for not only motor performance but also for cognition, emotion, memory and attention is increasingly being recognized and acknowledged. Since perturbed circuitry of cerebro-cerebellar trajectories can play a role in many central nervous system pathologies and thereby contribute to neurological symptoms in distinct neurodevelopmental and neurodegenerative diseases, is it the aim with this mini-review to highlight the pathways of glia–glia interplay being involved. The designs of future treatment strategies may hence be targeted to molecular pathways also playing a role in development and disease of the cerebellum. [ABSTRACT FROM AUTHOR]

Astrocytes play many distinct roles in the nervous system providing structural support for neurons and maintaining blood-brain barrier integrity. Steroid hormones exhibit a broad spectrum of actions in the central and peripheral nervous system, acting as trophic factors affecting cell differentiation and synaptic plasticity. In steroidogenesis, astrocytes play a key role by producing cholesterol, progesterone (P4), testosterone (T), and estradiol (E2). Currently there are only few studies which show that the Gly-Val-Ala-Pro-Gly (VGVAPG) peptide may affect the metabolism of astrocytes. Therefore, due to the role of neurosteroids, it is necessary to determine whether VGVAPG affects the level of E2, P4, and T in astrocytes. Primary mouse astrocytes were maintained in DMEM/F12 without phenol red, and supplemented with 10% charcoal/dextran-treated fetal bovine serum. Cells were exposed to 10 nM and 1 µM VGVAPG peptide and co-treated with cSrc kinase inhibitor I. After cell stimulation, we measured the Ki67 protein level and the production and secretion of P4, T, and E2. Our report presents the novel finding that the VGVAPG peptide affects the production and secretion of neurosteroids in astrocytes in vitro. The VGVAPG peptide increases the production of P4; however, at the same time, it decreases the secretion of P4 by astrocytes. On the other hand, it stimulates the production and secretion of T. Interestingly, the production of E2 did not change in any studied time interval. The expression of Ki67 protein increased after 48 h of exposition to the VGVAPG peptide. The cSrc kinase inhibitor I prevented most of the effects of VGVAPG peptide. Therefore, we postulate that T and cSrc kinase may be responsible for increasing astrocyte proliferation. [ABSTRACT FROM AUTHOR]

The present study evaluated biochemical endpoints characterizing acrylamide (ACR) neurotoxicity in the cortex of rats, following the possible neuroprotective activity of thymoquinone (TQ), an active constituent of Nigella sativa. ACR (50 mg/kg, intraperitoneal [i.p.]) concurrently with TQ (2.5, 5 and 10 mg/kg, i.p.) for 11 days were administered to rats. As positive control, vitamin E was used. After 11 days of injections, narrow beam test (NBT) was performed. The levels of reduced glutathione (GSH) and malondialdehyde (MDA) were measured and Western blotting was done for mitogen-activated protein kinases (MAPKinases) and apoptosis pathways proteins in the rats' cortex. Additionally, Evans blue assay was done to evaluate the integrity of blood brain barrier (BBB). Administration of ACR significantly induced gait abnormalities. A significant decrease and increase in the levels of GSH and MDA was observed in the cortex of ACR-treated rats, respectively. The elevation in the levels of caspases 3 and 9, glial fibrillary acidic protein (GFAP) content, and Bax/Bcl-2, P-P38/P38 and P-JNK/JNK ratios accompanied by reduction in myelin basic protein (MBP) content and P-ERK/ERK ratio were noticed in the ACR group. TQ (5 mg/kg) improved gait abnormalities, and restored these changes. ACR affected the integrity of BBB while TQ was able to maintain the integrity of this barrier. TQ reversed the alterations in the protein contents of MAP kinase and apoptosis signaling pathways as well as MBP and GFAP contents, induced by ACR. It protected against ACR-mediated neurotoxicity, partly through its antioxidant and antiapoptotic properties. [ABSTRACT FROM AUTHOR]

In the 1960s and 70s, biochemical and pharmacological evidence was pointing toward glutamate as a synaptic transmitter at a number of distinct receptor classes, known as NMDA and non-NMDA receptors. The field, however, lacked a potent and highly selective antagonist to block these putative postsynaptic receptors. So, the discoveries in the early 1980s of D-AP5 as a selective NMDA receptor antagonist and of its ability to block synaptic events and plasticity were a major breakthrough leading to an explosion of knowledge about this receptor subtype. During the next 10 years, the role of NMDA receptors was established in synaptic transmission, long-term potentiation, learning and memory, epilepsy, pain, among others. Hints at pharmacological heterogeneity among NMDA receptors were followed by the cloning of separate subunits. The purpose of this review is to recognize the important contributions made in the 1980s by Graham L. Collingridge and other key scientists to the advances in our understanding of the functions of NMDA receptors throughout the central nervous system. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a progressive condition, where dementia symptoms gradually worsen. Biochemically the disease is characterized by the presence of neuritic plaques, neurofibrillary tangles, in addition to cholinergic dysfunction in the central nervous system. The role of the cholinergic neurotransmission in AD is the basis of the widely accepted cholinergic hypothesis. Some of the most relevant therapies for the treatment of the disease are based on the acetylcholinesterase (AChE) inhibitor activity; however, these therapies are not effective to stop the disease progression, but only can temporarily slow down the worsening of dementia symptoms, and improve quality of life of patients and their caregivers. In recent years, plant alkaloids extracted from Amaryllidaceae family have received great attention due to the well-known anti cholinergic activity. In this context, the purpose of this study was to apply the docking molecular in sílico analysis aiming to examine the recombinant human AChE enzyme (rhAChE) inhibitory activity displayed by different alkaloids from Amaryllidaceae family. Overall, the present results support the idea that alkaloids reported in this research are capable of interacting with rhAChE-binding sites. [ABSTRACT FROM AUTHOR]

Retinoids (vitamin A and derivatives) are recognized as essential factors for central nervous system (CNS) development. Retinol (vitamin A) also was postulated to be a major antioxidant component of diet as it modulates reactive species (RS) production and oxidative stress in biological systems. Oxidative stress plays a major role either in pathogenesis or development of neurodegenerative diseases, or even in both. Here we investigate the role of retinol supplementation to human neuron-derived SH-SY5Y cells over RS production and biochemical markers associated to neurodegenerative diseases expressed at neuronal level in Parkinson's disease and Alzheimer's disease: α-synuclein, β-amyloid peptide, tau phosphorylation and RAGE. Retinol treatment (24 h) impaired cell viability and increased intracellular RS production at the highest concentrations (7 up to 20 µM). Antioxidant co-treatment (Trolox 100 µM) rescued cell viability and inhibited RS production. Furthermore, retinol (10 µM) increased the levels of α-synuclein, tau phosphorylation at Ser396, β-amyloid peptide and RAGE. Co-treatment with antioxidant Trolox inhibited the increased in RAGE, but not the effect of retinol on α-synuclein, tau phosphorylation and β-amyloid peptide accumulation. These data indicate that increased availability of retinol to neurons at levels above the cellular physiological concentrations may induce deleterious effects through diverse mechanisms, which include oxidative stress but also include RS-independent modulation of proteins associated to progression of neuronal cell death during the course of neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Inwardly rectifying K (Kir) channel expression signals at an advanced stage of maturation during oligodendroglial differentiation. Knocking down their expression halts the generation of myelin and produces severe abnormalities in the central nervous system. Kir4.1 is the main subunit involved in the tetrameric structure of Kir channels in glial cells; however, the precise composition of Kir channels expressed in oligodendrocytes (OLs) remains partially unknown, as participation of other subunits has been proposed. Kir channels are sensitive to H; thus, intracellular acidification produces Kir current inhibition. Since Kir subunits have differential sensitivity to H, we studied the effect of intracellular acidification on Kir currents expressed in cultured OLs derived from optic nerves of 12-day-old rats. Unexpectedly, Kir currents in OLs (2-4 DIV) did not change within the pH range of 8.0-5.0, as observed when using standard whole-cell voltage-clamp recording or when preserving cytoplasmic components with the perforated patch-clamp technique. In contrast, low pH inhibited astrocyte Kir currents, which was consistent with the involvement of the Kir4.1 subunit. The H-insensitivity expressed in OL Kir channels was not intrinsic because Kir cloning showed no difference in the sequence reported for the Kir4.1, Kir2.1, or Kir5.1 subunits. Moreover, when Kir channels were heterologously expressed in Xenopus oocytes they behaved as expected in their general properties and sensitivity to H. It is therefore concluded that Kir channel H-sensitivity in OLs is modulated through an extrinsic mechanism, probably by association with a modulatory component or by posttranslational modifications. [ABSTRACT FROM AUTHOR]

Astrocytes in the mammalian central nervous system are interconnected by gap junctions made from connexins of the subtypes Cx30 and Cx43. These proteins may exist as hemichannels in the plasma membrane in the absence of a 'docked' counterpart on the neighboring cell. A variety of stimuli are reported to open the hemichannels and thereby create a permeation pathway through the plasma membrane. Cx30 and Cx43 have, in their hemichannel configuration, been proposed to act as ion channels and membrane pathways for different molecules, such as fluorescent dyes, ATP, prostaglandins, and glutamate. Published studies about astrocyte hemichannel behavior, however, have been highly variable and/or contradictory. The field of connexin hemichannel research has been complicated by great variability in the experimental preparations employed, a lack of highly specific pharmacological inhibitors and by confounding changes associated with genetically modified animal models. This review attempts to critically assess the gating, inhibition and permeability of astrocytic connexin hemichannels and proposes that connexins in their hemichannel configuration act as gated pores with isoform-specific permeant selectivity. We expect that some, or all, of the controversies discussed here will be resolved by future research and sincerely hope that this review serves to motivate such clarifying investigations. [ABSTRACT FROM AUTHOR]

Neuronal survival, electrical signaling and synaptic activity require a well-balanced micro-environment in the central nervous system. This is achieved by the blood-brain barrier (BBB), an endothelial barrier situated in the brain capillaries, that controls near-to-all passage in and out of the brain. The endothelial barrier function is highly dependent on signaling interactions with surrounding glial, neuronal and vascular cells, together forming the neuro-glio-vascular unit. Within this functional unit, connexin (Cx) channels are of utmost importance for intercellular communication between the different cellular compartments. Connexins are best known as the building blocks of gap junction (GJ) channels that enable direct cell-cell transfer of metabolic, biochemical and electric signals. In addition, beyond their role in direct intercellular communication, Cxs also form unapposed, non-junctional hemichannels in the plasma membrane that allow the passage of several paracrine messengers, complementing direct GJ communication. Within the NGVU, Cxs are expressed in vascular endothelial cells, including those that form the BBB, and are eminent in astrocytes, especially at their endfoot processes that wrap around cerebral vessels. However, despite the density of Cx channels at this so-called gliovascular interface, it remains unclear as to how Cx-based signaling between astrocytes and BBB endothelial cells may converge control over BBB permeability in health and disease. In this review we describe available evidence that supports a role for astroglial as well as endothelial Cxs in the regulation of BBB permeability during development as well as in disease states. [ABSTRACT FROM AUTHOR]

It is now well accepted that astrocytes are essential in all major nervous system functions of the rodent brain, including neurotransmission, energy metabolism, modulation of blood flow, ion and water homeostasis, and, indeed, higher cognitive functions, although the contribution of astrocytes in cognition is still in early stages of study. Here we review the most current research findings on human astrocytes, including their structure, molecular characterization, and functional properties. We also highlight novel tools that have been established for translational approaches to the comparative study of astrocytes from humans and experimental animals. Understanding the differences in astrocytes is essential to elucidate the contribution of astrocytes to normal physiology, cognitive processing and diverse pathologies of the central nervous system. [ABSTRACT FROM AUTHOR]

A wide heterogeneity of lesions can affect the central nervous system (CNS). In all situations where neurons are damaged, including multiple sclerosis (MS), a common reactive astrocytosis is present. Sedimentation field-flow fractionation (SdFFF) was used to sort astrocyte subpopulations. After SdFFF elution, cells, prepared from rat newborn cortex, were cultured and analyzed by immunocytofluorescence for glial fibrillary acidic protein (GFAP) and α-smooth muscle (SM) actin (a specific marker for myofibroblasts) expression. Cell contractile capacity was studied. Samples from patients with MS were also analyzed. Three main fractions (F1, F2, and F3) were isolated and compared with the total eluted population (TP). TP, F1, F2, and F3, contained respectively 74, 96, 12, and 98% of GFAP expressing astrocytes. In F3, astrocytes only expressed GFAP while in F1, astrocytes expressed both GFAP and α-SM actin. In F2 and TP, α-SM actin expression was barely detected. F3-derived cells showed higher contractile capacities compared with F1-derived cells. In one specific case of MS known as Baló's concentric MS, astrocytes expressing both GFAP and α-SM actin were detected. Using SdFFF, a population of astrocytes presenting myofibroblast properties was isolated. This subpopulation of astrocytes was also observed in a MS sample suggesting that it could be involved in lesion formation and remodeling during CNS pathologies. [ABSTRACT FROM AUTHOR]

Valproic acid (VPA), an anticonvulsant and mood-stabilizing drug, can induce neuronal differentiation, promote neurite extension and exert a neuroprotective effect in central nervous system (CNS) injuries; however, comparatively little is known regarding its action on mouse embryonic neural stem cells (NSCs) and the underlying molecular mechanism. Recent studies suggested that c-Jun N-terminal kinase (JNK) is required for neurite outgrowth and neuronal differentiation during neuronal development. In the present study, we cultured mouse embryonic NSCs and treated the cells with 1 mM VPA for up to 7 days. The results indicate that VPA promotes the neuronal differentiation of mouse embryonic NSCs and neurite outgrowth of NSC-derived neurons; moreover, VPA induces the phosphorylation of c-Jun by JNK. In contrast, the specific JNK inhibitor SP600125 decreased the VPA-stimulated increase in neuronal differentiation of mouse embryonic NSCs and neurite outgrowth of NSC-derived neurons. Taken together, these results suggest that VPA promotes neuronal differentiation of mouse embryonic NSCs and neurite outgrowth of NSC-derived neurons. Moreover, JNK activation is involved in the effects of VPA stimulation. [ABSTRACT FROM AUTHOR]

β-Hydroxybutyrate (βOHB), a ketone body, is oxidised as a brain fuel. Although its contribution to energy metabolism in the healthy brain is minimal, it is an interesting metabolite which is not only oxidised but also has other direct and collateral effects which make it a molecule of interest for therapeutic purposes. In brain βOHB can be produced in astrocytes from oxidation of fatty acids or catabolism of amino acids and is metabolised in the mitochondria of all brain cell types although uptake across the blood brain barrier is a metabolic control point. βOHB possesses an intrinsic high heat of combustion, making it an efficient mitochondrial fuel, where it can alter the NAD/NADH and Q/QH couples and reduce production of mitochondrial reactive oxygen species. It can directly interact as a signalling molecule influencing opening of K channels and regulation of Ca channels. βOHB is an inhibitor of histone deacetylases resulting in upregulation of genes involved in protection against oxidative stress and regulation of metabolism. It interacts with an inflammasome in immune cells to reduce production of inflammatory cytokines and reduce inflammation. Use of βOHB as an efficient neurotherapeutic relies on increasing blood βOHB levels so as to encourage entry of βOHB to the brain. While use of βOHB as a sole therapeutic is currently limited, with employment of a ketogenic diet a more widely used approach, recent development and testing of esterified forms of βOHB have shown great promise, with the approach elevating plasma βOHB while allowing consumption of normal diet. An improved understanding of the mechanisms by which βOHB acts will allow better design of both diet and supplemental interventions. [ABSTRACT FROM AUTHOR]

Intrauterine growth restricted (IUGR) infants are at increased risk for neurodevelopmental deficits that suggest the hippocampus and cerebral cortex may be particularly vulnerable. Evaluate regional neurochemical profiles in IUGR and normally grown (NG) 7-day old rat pups using in vivo H magnetic resonance (MR) spectroscopy at 9.4 T. IUGR was induced via bilateral uterine artery ligation at gestational day 19 in pregnant Sprague-Dawley dams. MR spectra were obtained from the cerebral cortex, hippocampus and striatum at P7 in IUGR (N = 12) and NG (N = 13) rats. In the cortex, IUGR resulted in lower concentrations of phosphocreatine, glutathione, taurine, total choline, total creatine ( P < 0.01) and [glutamate]/[glutamine] ratio ( P < 0.05). Lower taurine concentrations were observed in the hippocampus ( P < 0.01) and striatum ( P < 0.05). IUGR differentially affects the neurochemical profile of the P7 rat brain regions. Persistent neurochemical changes may lead to cortex-based long-term neurodevelopmental deficits in human IUGR infants. [ABSTRACT FROM AUTHOR]

Both neuroinflammation and microglial activation are pathological markers of a number of central nervous system (CNS) diseases. During chronic activation of the microglial cells, the induced release of excessive amounts of reactive oxygen species (ROS) and pro-inflammatory cytokines have been implicated in several neurodegenerative diseases such as Alzheimer's disease. Thymoquinone (TQ), a major bioactive compound of the natural product Nigella sativa seed, has been shown to be effective against numerous oxidative stress-induced and inflammatory disorders as well as possess neuroprotective properties. In this study, we investigated the antioxidant effects of TQ on LPS/IFNγ or HO-activated BV-2 microglia by assessing the levels of specific oxidative stress markers, the activities of selected antioxidant enzymes, as well as profiling 84 key genes related to oxidative stress via real-time reverse transcription (RT) PCR array. Our results showed that in the LPS/IFNγ-activated microglia TQ significantly decreased the cellular production of both superoxide and nitric oxide fourfold (p < 0.0001) and sixfold (p < 0.0001), respectfully. In the HO-activated microglia, TQ also significantly decreased the cellular production of superoxide threefold (p < 0.0001) and significantly decreased hydrogen peroxide levels ~20 % (p < 0.05). Moreover, ΤQ treatment significantly decreased the levels oxidative stress in the activated BV-2 as evidenced by the assessed levels of lipid hydroperoxides and glutathione. TQ significantly decreased the levels of lipid hydroperoxides twofold (p < 0.0001) and significantly increased the levels of antioxidant glutathione 2.5-fold (p < 0.0001) in the LPS/IFNγ-activated BV-2 cells. In the HO-activated microglia, TQ significantly decreased lipid hydroperoxides eightfold (p < 0.0001) and significantly increased glutathione 15 % (p < 0.05). Activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT), in the TQ-treated microglial cells also reflected a reduced oxidative stress status in the cellular environment. SOD and CAT activities were sixfold (p < 0.0001) and fivefold (p < 0.0001) lower, respectfully, for the LPS/INFγ-activated microglia treated with TQ in comparison to those that were not. For the HO-activated microglia treated with TQ, SOD and CAT activities were fivefold (p < 0.0001) and threefold (p < 0.01) lower, respectfully, compared to the untreated. Furthermore, RT PCR array profiling of the selected 84 genes related to oxidative stress confirmed that TQ treatment in the LPS/IFNγ-activated microglia downregulates specific pro-oxidant genes, upregulates specific anti-oxidant genes, and enhances the up- or downregulation of specific genes related to the cells' natural antioxidant defense against LPS/IFNγ activation. These findings suggest that TQ may be utilized as an effective therapeutic agent for delaying the onset and/or slowing/preventing the progression of microglia-derived neurodegeneration propagated by excessive oxidative stress in the CNS. [ABSTRACT FROM AUTHOR]

During development, the secreted molecule Sonic Hedgehog (Shh) is required for lineage specification and proliferation of oligodendrocyte progenitors (OLPs), which are the glia cells responsible for the myelination of axons in the central nervous system (CNS). Shh signaling has been implicated in controlling both the generation of oligodendrocytes (OLGs) during embryonic development and their production in adulthood. Although, some evidence points to a role of Shh signaling in OLG development, its involvement in OLG differentiation remains to be fully determined. The objective of this study was to assess whether Shh signaling is involved in OLG differentiation after neural stem cell commitment to the OLG lineage. To address these questions, we manipulated Shh signaling using cyclopamine, a potent inhibitor of Shh signaling activator Smoothened (Smo), alone or combined with the agonist SAG in OLG primary cultures and assessed expression of myelin-specific markers. We found that inactivation of Shh signaling caused a dose-dependent decrease in myelin basic protein (MBP) and myelin associated glycoprotein (MAG) in differentiating OLGs. Co-treatment of the cells with SAG reversed the inhibitory effect of cyclopamine on both myelin-specific protein levels and morphological changes associated with it. Further experiments are required to elucidate the molecular mechanism by which Shh signaling regulates OLG differentiation. [ABSTRACT FROM AUTHOR]

The VHL (Von Hippel-Lindau) gene is a tumor suppressor gene, which is best known as an E3 ubiquitin ligase that negatively regulates the hypoxia inducible factor. The inactivation of VHL gene could result in the abnormal synthesis of VHL protein, which is in contact with the development and occurrence of renal clear cell carcinoma. However, the expression and possible function of VHL in central nervous system (CNS) is still unclear. To examine the function of VHL in CNS injury and repair, we used an acute spinal cord injury (SCI) model in adult rats. Western blot analysis showed an important upregulation of VHL protein, reaching a peak at day 3 and then declined during the following days. Double immunofluorescence staining showed that VHL was co-expressed with neurons, but not with astrocytes and microglia. Moreover, we detected that active caspase-3 had co-localized with VHL in neurons after SCI. Additionally in vitro, VHL depletion, by short interfering RNA, significantly reduced neuronal apoptosis. In conclusion, these data suggested that the change of VHL protein expression was related to neuronal apoptosis after SCI. [ABSTRACT FROM AUTHOR]

Arecoline is a major alkaloid of areca nut and has been effect on central nervous system. Although arecoline-induced neurotoxicity has been reported, the possible underlying neurotoxic mechanisms have not yet been elucidated. Increasing evidences have shown that both excessive endoplasmic reticulum (ER) stress and disturbance of hydrogen sulfide (HS) production are involved in the pathophysiology of numerous neurodegenerative diseases. Here, the purpose of present study was to verify whether ER stress and the disturbance of endogenous HS generation are also involved in arecoline-caused neurotoxicity. We found that treatment of PC12 cells with arecoline induced the down-regulation of cells viability and up-regulation of apoptosis and the activity of caspase-3, indicating the neurotoxic role of arecoline to PC12 cells. In addition, arecoline also increased the expression of Bax (pro-apoptotic protein) and attenuated the expression of Bcl-2 (anti-apoptotic protein) in PC12 cells. Simultaneously, arecoline caused excessive ER stress in PC12 cells, as evidenced by the up-regulations of Glucose-regulated protein 78 (GRP78), CCAAT/enhancer binding protein homologous protein (CHOP), and Cleaved caspase-12 expressions. Notably, the level of HS in the culture supernatant and the expressions of cystathionine β-synthase and 3-mercaptopyruvate sulfurtransferase (two major enzymes for endogenous HS generation in PC12 cells) were also reduced by arecoline treatment. These results indicate that arecoline-caused neurotoxicity to PC12 cells is involved in ER stress and disturbance of endogenous HS generation and suggest that the modulation of ER stress and endogenous HS generation may be potential therapeutic approach in treatment of arecoline-caused neurotoxicity. [ABSTRACT FROM AUTHOR]

The central nervous system (CNS) harbors multiple glial fibrillary acidic protein (GFAP) expressing cell types. In addition to the most abundant cell type of the CNS, the astrocytes, various stem cells and progenitor cells also contain GFAP+ populations. Here, in order to distinguish between two types of GFAP expressing cells with or without the expression of the A2B5 antigens, we performed lipidomic analyses on A2B5+/GFAP+ and A2B5−/GFAP+ cells from rat spinal cord. First, A2B5+/GFAP− progenitors were exposed to the leukemia inhibitory factor (LIF) or bone morphogenetic protein (BMP) to induce their differentiation to A2B5+/GFAP+ cells or A2B5−/GFAP+ astrocytes, respectively. The cells were then analyzed for changes in their phospholipid, sphingolipid or acyl chain profiles by mass spectrometry and gas chromatography. Compared to A2B5+/GFAP− progenitors, A2B5−/GFAP+ astrocytes contained higher amounts of ether phospholipids (especially the species containing arachidonic acid) and sphingomyelin, which may indicate characteristics of cellular differentiation and inability for multipotency. In comparison, principal component analyses revealed that the lipid composition of A2B5+/GFAP+ cells retained many of the characteristics of A2B5+/GFAP− progenitors, but their lipid profile was different from that of A2B5−/GFAP+ astrocytes. Thus, our study demonstrated that two GFAP+ cell populations have distinct lipid profiles with the A2B5+/GFAP+ cells sharing a phospholipid profile with progenitors rather than astrocytes. The progenitor cells may require regulated low levels of lipids known to mediate signaling functions in differentiated cells, and the precursor lipid profiles may serve as one measure of the differentiation capacity of a cell population. [ABSTRACT FROM AUTHOR]

The study assessed involvement of Ca signaling mediated by the metabotropic glutamate receptors mGluR1/5 in brain tolerance induced by hypoxic preconditioning. Acute slices of rat piriform cortex were tested 1 day after exposure of adult rats to mild hypobaric hypoxia for 2 h at a pressure of 480 hPa once a day for three consecutive days. We detected 44.1 ± 11.6 % suppression of in vitro anoxia-induced increases of intracellular Ca levels and a fivefold increase in Ca transients evoked by selective mGluR1/5 agonist, DHPG. Western blot analysis of cortical homogenates demonstrated a 11 ± 4 % decrease in mGluR1 immunoreactivity (IR), and in the nuclei-enriched fraction a 12 ± 3 % increase in IR of phospholipase Cβ1 (PLCβ1), which is a major mediator of mGluR1/5 signaling. Immunocytochemical analysis of the cortex revealed increase in the mGluR1/5 and PLCβ1 IR in perikarya, and a decrease in IR of the neuronal inositol trisphosphate receptors (IP3Rs). We suggest that enhanced expression of mGluR5 and PLCβ1 and potentiation of Ca signaling may represent pro-survival upregulation of Ca-dependent genomic processes, while decrease in mGluR1 and IP3R IR may be attributed to a feedback mechanism preventing excessive intracellular Ca release. [ABSTRACT FROM AUTHOR]

The Src family kinases are a family of intracellular, non-receptor tyrosine kinases that are involved in a variety of cellular functions including the regulation of inflammation and apoptosis after brain hypoxia. Caspase-1 (C1) activates IL-1β through the formation of complex structures, the inflammasomes, while caspase-8 (C8) is part of the extrinsic apoptotic pathway. C8 has been found to directly activate the production of IL-1β. Previously, we observed that C1 and IL-1β are increased in the acute phase after hypoxia in the brain of piglets, but they follow a different pattern long term, with C1 remaining activated throughout the period of observation, while IL-1β returning to baseline at 15 days. Src kinase inhibition ameliorated the activation of C1 and IL-1β early, but did not appear to have any effect long term. Prompted by these findings, we assessed the changes that occur over time (1 h and 15 days) in C1 and C8 activities after brain hypoxia as well as the effect of pretreatment with a Src kinase inhibitor, PP2 on these biochemical markers. Enzymatic activities were determined by spectrophotometry with measurements of C1 and C8 in each cytosolic brain sample (N = 4 in each group). We found that C1 and C8 activities increase in the acute phase following hypoxia in the brain of newborn piglets, with C8 relatively more than C1 (C8/C1 ratio increased from 2:1 as baseline to 3:1 in hypoxia). Fifteen days after hypoxia C8/C1 ratio decreased to about 1:1. In piglets that were pretreated with a Src kinase selective inhibitor (PP2) and then subjected to hypoxia, the C8/C1 ratio early increase was not observed. Immediately after hypoxia C8 and C1 follow a similar pattern of increase while long term this appears to dissociate. We propose that following this experimental methodology, the previously observed IL-1β production after hypoxia might be associated with C8 rather than C1 and that Src kinase is involved in the above process. [ABSTRACT FROM AUTHOR]

Substance P (SP) play a central role in nociceptive transmission and it is an agonist of the Neurokinin-1 receptor located in the lamina I of the spinal cord. SP is a major proteolytic product of the protachykinin-1 primarily synthesized in neurons. Proprotein convertases (PCs) are extensively expressed in the central nervous system and specifically cleave at C-terminal of either a pair of basic amino acids, or a single basic residue. The proteolysis control of endogenous protachykinins has a profound impact on pain perception and the role of PCs remain unclear. The objective of this study was to decipher the role of PC1 and PC2 in the proteolysis surrogate protachykinins (i.e. Tachykinin 20-68 and Tachykinin 58-78) using cellular fractions of spinal cords from wild type (WT), PC1 and PC2 animals and mass spectrometry. Full-length Tachykinin 20-68 and Tachykinin 58-78 was incubated for 30 min in WT, PC1 and PC2 mouse spinal cord S9 fractions and specific C-terminal peptide fragments were identified and quantified by mass spectrometry. The results clearly demonstrate that both PC1 and PC2 mediate the formation of SP and Tachykinin 58-71, an important SP precursor, with over 50 % reduction of the rate of formation in mutant PC1 and PC2 mouse S9 spinal cord fractions. The results obtained revealed that PC1 and PC2 are involved in the C-terminal processing of protachykinin peptides and suggest a major role in the maturation of the protachykinin-1 protein. [ABSTRACT FROM AUTHOR]

Brain serotonergic signaling is coupled to arachidonic acid (AA)-releasing calcium-dependent phospholipase A. Increased brain serotonin concentrations and disturbed serotonergic neurotransmission have been reported in the Flinders Sensitive Line (FSL) rat model of depression, suggesting that brain AA metabolism may be elevated. To test this hypothesis, C-AA was intravenously infused to steady-state levels into control and FSL rats derived from the same Sprague-Dawley background strain, and labeled and unlabeled brain phospholipid and plasma fatty acid concentrations were measured to determine the rate of brain AA incorporation and turnover. Brain AA incorporation and turnover did not differ significantly between controls and FSL rats. Compared to controls, plasma unesterified docosahexaenoic acid was increased, and brain phosphatidylinositol AA and total lipid linoleic acid and n-3 and n-6 docosapentaenoic acid were significantly decreased in FSL rats. Several plasma esterified fatty acids differed significantly from controls. In summary, brain AA metabolism did not change in FSL rats despite reported increased levels of serotonin concentrations, suggesting possible post-synaptic dampening of serotonergic neurotransmission involving AA. [ABSTRACT FROM AUTHOR]

Tetramethylpyrazine (TMP) has been suggested to have neuroprotective effects against spinal cord injury (SCI); however, few studies have examined these effects and the corresponding mechanism. Therefore, the present study aimed to investigate the neuroprotective effect and underlying mechanism of TMP against contusive SCI. Adult male Sprague-Dawley rats were randomly divided into Sham, normal saline (NS) and TMP groups. Each group was divided into subgroups according to the time of sacrifice: 1, 3, 7, 14, 21 and 28 days post-injury. Laminectomy was performed in all groups, followed by contusive SCI establishment in the TMP and NS groups. TMP (80 mg/kg) was injected thereafter daily from 3 to 7 days post-injury in the TMP group, which was replaced by equal volume of normal saline in the NS group. The Basso-Beattie-Bresnahan (BBB) Locomotor Rating Scale was measured at different time points post-injury to appraise locomotor functional recovery. Quantitative real-time PCR and immunofluorescence were used to assess the spatio-temporal expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), while western blot was adopted to detect the effect of TMP on PGC-1α. Neural apoptotic changes and neuronal survival were evaluated using the TUNEL method and Nissl staining, respectively. TMP treatment markedly increased PGC-1α expression, neuronal survival and BBB locomotor scores, while also reducing neural apoptosis. These results demonstrate that TMP is neuroprotective against contusive SCI, with the inhibition of neural apoptosis and increase of neuronal survival. The sustained expression of PGC-1α may partially contribute to the TMP-mediated neuroprotective effect. [ABSTRACT FROM AUTHOR]

Mitochondrial division inhibitor 1 (Mdivi-1) is the most effective pharmacological inhibitor of mitochondrial fission. Spinal cord injury (SCI) is a common and serious trauma, which lacks efficient treatment. This study aimed to detect the role of Mdivi-1 in neuronal injury and its underlying mechanism after acute SCI (ASCI) in rats. Western blot analysis showed that Bax levels on the mitochondrial outer membrane, and release of cytochrome C (cytC) and apoptosis-inducing factor (AIF) from the mitochondria began to increase significantly at 4 h after ASCI, then peaked at 16 h, and declined significantly from 16 to 24 h. However, the mitochondrial levels of Bcl-2 increased significantly at 2 h, peaked at 4 h, and subsequently significantly decreased from 4 to 24 h after ASCI. In addition, Mdivi-1(1.2 mg/kg) significantly suppressed the translocation of dynamin-related protein 1 (Drp1) and Bax to the mitochondria, mitochondrial depolarization, decrease of ATP and reduced Glutathione, increase of the Malondialdehyde, cytC release, and AIF translocation at 16 h and 3 days after ASCI, and also inhibited the caspase-3 activation and decrease of the percentage of apoptotic cells at 16 h, 3 and 10 days, further, ameliorated the motor dysfunction greatly from 3 to 10 days after ASCI in rats. This neuroprotective effect was dose-dependent. However, Mdivi-1(1.2 mg/kg) had no effects on the translocation of Bcl-2 and fission protein 1 on the mitochondria, and did not affect the expression of total Drp1 at 16 h after ASCI. Our experimental findings indicated that Mdivi-1 can protect rats against ASCI, and that its underlying mechanism may be associated with inhibition of Drp1 translocation to the mitochondria, alleviation of mitochondrial dysfunction and oxidative stress, and suppression of caspase-dependent and -independent apoptosis. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a progressive neurodegenerative disease with motor and non-motor symptoms that precede the onset of motor symptoms. Rotenone is often used to induce PD-like pathology in the central nervous system (CNS) and enteric nervous system (ENS). However, there is little or no information on the temporal changes in other neural tissues and the spread of pathology throughout the entire body organs. Here, we recorded the serial immunohistochemical changes in neurons and glial cells of the striatum, substantia nigra (SN), olfactory bulb (OB), thoracic cord (ThC) and ascending colon (AC) induced by 1-, 3- and 6-week administration of rotenone (50 mg/kg/day) infused subcutaneously in C57BL mice using an osmotic pump. Rotenone exposure for 3 or 6 weeks caused neurodegeneration in the striatum, whereas neuronal damage was seen in the SN and OB only after 6 weeks. Moreover, rotenone induced neurodegeneration in the myenteric plexus of AC but not in ThC. Rotenone also activated glial cells before any apparent neurodegeneration in the CNS but not in the ENS. Our results demonstrated that subcutaneous administration of rotenone can cause progressive neurodegeneration in the OB and AC, in addition to the nigrostriatal pathway, and temporal differential glial activation, and that these changes do not spread retrogradely from OB or ENS to nigrostriatal pathway. The results suggested that the different vulnerability of neurons to the neurotoxic effects of rotenone administrated subcutaneously are due to glial activation in these neural tissues. [ABSTRACT FROM AUTHOR]

Human cytomegalovirus (HCMV) infections are the leading cause of viral induced birth defects, affecting the central nervous system (CNS) primarily. Fetal CNS is especially vulnerable to CMV induced injury. As HCMV permissive cells, astrocytes are responsible for major glutamate transport and regulate extracellular levels of glutamate avoiding its accumulation which is implicated in neurodegenerative disorders. In this study, highly purified astrocytes isolated from human first trimester aborted fetal brain were infected with HCMV AD169, glutamate uptake function was detected by H labeling technic, and the expression level alterations of glutamate transporters (GLAST, GLT-1), glutamine synthetase (GS) and its activity were also investigated. Protein kinases C (PKC) inhibitor treatment was to identify whether PKC signalling involved in regulating glutamate uptake, protein expression of GLAST, GLT-1, GS and GS activity. Results indicated HCMV AD169 infection could modulate glutamate uptake, expression levels of GLAST, GLT-1, GS and it activity through PKC signalling, suggesting a great susceptibility of human fetal astrocytes to HCMV infection, which significantly alters the uptake and metabolism of an important excitatory amino acid, glutamate, may be a potential mechanism for HCMV associated neurological disease, and an effective therapeutic target in neural diseases. [ABSTRACT FROM AUTHOR]

Multiple sclerosis (MS) is an inflammatory neurodegenerative disease of the central nervous system (CNS) which leads to progressive neurological disability. Our previous studies have demonstrated mitochondrial involvement in MS cortical pathology and others have documented decreased levels of the neuronal mitochondrial metabolite N-acetyl aspartate (NAA) in the MS brain. While NAA is synthesized in neurons, it is broken down in oligodendrocytes into aspartate and acetate. The resulting acetate is incorporated into myelin lipids, linking neuronal mitochondrial function to oligodendrocyte-mediated elaboration of myelin lipids in the CNS. In the present study we show that treating human SH-SY5Y neuroblastoma cells with the electron transport chain inhibitor antimycin A decreased levels of NAA as measured by HPLC. To better understand the significance of the relationship between mitochondrial function and levels of NAA and its breakdown product acetate on MS pathology we then quantitated the levels of NAA and acetate in MS and control postmortem tissue blocks. Regardless of lesion status, we observed that levels of NAA were decreased 25 and 32 % in gray matter from parietal and motor cortex in MS, respectively, compared to controls. Acetate levels in adjacent white matter mirrored these decreases as evidenced by the 36 and 45 % reduction in acetate obtained from parietal and motor cortices. These data suggest a novel mechanism whereby mitochondrial dysfunction and reduced NAA levels in neurons may result in compromised myelination by oligodendrocytes due to decreased availability of acetate necessary for the synthesis of myelin lipids. [ABSTRACT FROM AUTHOR]

Nogo-A is a myelin-derived inhibitor playing a pivotal role in the prevention of axonal regeneration. A functional domain of Nogo-A, Amino-Nogo, exerts an inhibitory effect on axonal regeneration, although the mechanism is unclear. The present study investigated the role of the Amino-Nogo-integrin signaling pathway in primary retinal ganglion cells (RGCs) with respect to axonal outgrowth, which is required for axonal regeneration. Immunohistochemistry showed that integrin αv, integrin α5 and FAK were widely expressed in the visual system. Thy-1 and GAP-43 immunofluorescence showed that axonal outgrowth of RGCs was promoted by Nogo-A siRNA and a peptide antagonist of the Nogo-66 functional domain of Nogo-A (Nep1-40), and inhibited by a recombinant rat Nogo-A-Fc chimeric protein (△20). Western blotting revealed increased integrin αv and p-FAK expression in Nogo-A siRNA group, decreased integrin αv expression in △20 group and decreased p-FAK expression in Nep1-40 group. Integrin α5 expression was not changed in any group. RhoA G-LISA showed that RhoA activation was inhibited by Nogo-A siRNA and △20, but increased by Nep1-40 treatment. These results suggest that Amino-Nogo inhibits RGC axonal outgrowth primarily through the integrin αv signaling pathway. [ABSTRACT FROM AUTHOR]

Acid-sensing ion channels (ASIC) play an important role in the central neuronal system and excessive activation of ASICs induces neuronal damage. Recent studies show that ASIC1a, a subunit of ASIC, is involved in stress processes but the mechanisms by which ASIC1a is regulated by corticosterone (CORT), a stress-induced hormone, are as yet unelucidated. In the present study, to explore the effects of CORT on ASIC1a in cultured hippocampal neurons, the whole-cell patch clamp technique was used. We present data showing that extracellular application of 1 and 10 μM CORT increase the inward current when solution of pH 6.0 is applied to the exterior of the cell. Moreover, extracellular application of membrane-impermeable CORT-BSA (1 μM) maintains current elevation induced by the action of ASIC1a. However, intracellular application of CORT (1 μM) did not increase ASIC1a current. Subsequent extracellular application of CORT enhanced the amplitude of ASIC1a current. Also, RU38486 (10 μM), an antagonist of nuclear glucocorticoids receptor, did not block an increase of ASIC1a current induced by CORT. In addition, CORT application further resulted in a significant enhancement of ASIC1a current in the presence of phorbol 12-myristate 13-acetate (0.5 μM) or bryostatin1 (1 μM), which are both protein kinase C (PKC) agonists. On the contrary, after pretreatment with GF109203X (3 μM), an antagonist of PKC, CORT did not elevate ASIC1a current. These data indicate that the rapid increase of ASIC1a current induced by CORT may be caused by the activation of corticosteroid receptors found on the cell membranes of hippocampal neurons and it may involve a PKC-dependent mechanism. [ABSTRACT FROM AUTHOR]

Phospholipases A (PLA) are enzymes that cleave the sn-2 bond of membrane phospholipids to yield free fatty acids and lysophospholipids. Secretory PLA-III (sPLA-III) has been suggested to be important for neuronal differentiation, growth and survival, and is highly expressed in the spinal cord. The aim of this study is to elucidate its expression and distribution in different regions of the adult rat CNS. Quantitative RT-PCR analyses showed high levels of sPLA-III mRNA expression in the brainstem and spinal cord and low expression in the olfactory bulb. Western blot analyses showed high level of expression in the brainstem, spinal cord and cerebral neocortex. A dense band corresponding to the catalytically active, mature/cleaved form, and a faint band corresponding to the full length sPLA-III were detected in post-mitochondrial supernatants, from different parts of the CNS. Subcellular fractionation of spinal cord homogenates showed that sPLA-III protein is present in the 'light membrane/cytosol' fraction, but not the nucleus, synaptosomal membrane or synaptic vesicle-enriched fractions. sPLA-III was immunolocalized to neurons in the cerebral neocortex, Purkinje neurons in the cerebellar cortex, periaqueductal gray, red nucleus, spinal trigeminal nucleus and dorsal horn of the spinal cord. Electron microscopy of the spinal cord and cerebral neocortex showed that sPLA-III was localized in dendrites or dendritic spines, that formed asymmetrical synapses with unlabeled, putatively glutamatergic, axon terminals. The localization of mature/cleaved form of sPLA-III in postsynaptic structures suggest a physiological role of the enzyme in neurotransmission or synaptic plasticity. [ABSTRACT FROM AUTHOR]