MicroRNA-130a regulates neurological deficit and angiogenesis in rats with ischaemic stroke by targeting XIAP.

MicroRNAs (miRNAs) have already been proposed to be implicated in the development of ischaemic stroke. We aim to investigate the role of miR-130a in the neurological deficit and angiogenesis in rats with ischaemic stroke by regulating X-linked inhibitor of apoptosis protein (XIAP). Middle cerebral artery occlusion (MCAO) models were established by suture-occluded method, and MCAO rats were then treated with miR-130a mimics/inhibitors or/and altered XIAP for detection of changes of rats' neurological function, nerve damage and angiogenesis in MCAO rats. The oxygen-glucose deprivation (OGD) cellular models were established and respectively treated to determine the roles of miR-130a and XIAP in neuronal viability and apoptosis. The expression levels of miR-130a and XIAP in brain tissues of MCAO rats and OGD-treated neurons were detected. The binding site between miR-130a and XIAP was verified by luciferase activity assay. MiR-130a was overexpressed while XIAP was down-regulated in MCAO rats and OGD-treated neurons. In animal models, suppressed miR-130a improved neurological function, alleviated nerve damage and increased new vessels in brain tissues of rats with MCAO. In cellular models, miR-130a inhibition promoted neuronal viability and suppressed apoptosis. Inhibited XIAP reversed the effect of inhibited miR-130a in both MCAO rats and OGD-treated neurons. XIAP was identified as a target of miR-130a. Our study reveals that miR-130a regulates neurological deficit and angiogenesis in rats with MCAO by targeting XIAP.

Hematopoietic Stem Cell Gene Therapy for Storage Disease: Current and New Indications.

Lysosomal storage disorders (LSDs) are a broad class of monogenic diseases with an overall incidence of 1:7,000 newborns, due to the defective activity of one or more lysosomal hydrolases or related proteins resulting in storage of un-degraded substrates in the lysosomes. The over 40 different known LSDs share a life-threatening nature, but they are present with extremely variable clinical manifestations, determined by the characteristics and tissue distribution of the material accumulating due to the lysosomal dysfunction. The majority of LSDs lack a curative treatment. This is particularly true for LSDs severely affecting the CNS. Based on current preclinical and clinical evidences, among other treatment modalities, hematopoietic stem cell gene therapy could potentially result in robust therapeutic benefit for LSD patients, with particular indication for those characterized by severe brain damage. Optimization of current approaches and technology, as well as implementation of clinical trials for novel indications, and prolonged and more extensive follow-up of the already treated patients will allow translating this promise into new medicinal products.

Dravet syndrome--from epileptic encephalopathy to channelopathy.

Mutations in the gene encoding the α1 subunit of the voltage gated sodium channel (SCN1A) are associated with several epilepsy syndromes, ranging from relatively mild phenotypes found in families with genetic epilepsy with febrile seizures plus (GEFS+) to the severe infant-onset epilepsy Dravet syndrome. Evidence has emerged of the consequences of SCN1α dysfunction in different neuronal networks across the brain pointing toward a channelopathy model causing the neurologic features of Dravet syndrome that is beyond purely seizure related damage. A genetic change will present according to its severity, the genetic background of the individual, and environmental factors, and will affect a variety of neuronal networks according to channel distribution. This already-vulnerable system may be susceptible to secondary aggravating events such as status epilepticus. The channelopathy model implies that pharmacologic treatment and the restoration of impaired γ-aminobutyric acid (GABA)ergic neurotransmission might not only help prevent seizures but might affect the comorbidities of the syndrome. This critical review explores recent evidence relating to the pathogenicity of SCN1A mutations in Dravet syndrome and the effect these have on the wider disease phenotype and discusses whether knowledge of specific genotypes can influence clinical practice. Genetic technology is currently advancing at unprecedented speed and will increase our knowledge of new genes and interacting genetic networks. Clinicians and geneticists will have to work in close collaboration to guarantee good delivery and counseling of genetic testing results.

[Schizophrenia and cognition: a neurodevelopmental approach]. / Schizophrénie et cognition: perspective neurodéveloppementale.

Accumulating evidence supports the hypothesis of abnormal neurodevelopment in schizophrenia. According to this hypothesis, schizophrenia is the consequence of prenatal abnormalities resulting from the interaction of genetic and environmental factors. In line with this hypothesis, several studies indicate that pregnancy and birth complications are risk factors for developing schizophrenia. At the clinical level, multiple cognitive deficits can be found in schizophrenic patients before illness onset. The neurodevelopmental hypothesis considers these cognitive deficits as the expression of early abnormalities on the central nervous system development. Consistently, brain imaging data show early structural abnormalities and abnormal progressive brain changes in schizophrenia. Finally, genetic and histological data indicate that genes associated with schizophrenia are involved in brain development.

Early rise in brain damage markers and high ICOS expression in CD4+ and CD8+ T cells during checkpoint inhibitor-induced encephalomyelitis.

We report a case of rapid eradication of melanoma brain metastases and simultaneous near-fatal encephalomyelitis following double immune checkpoint blockade. Brain damage marker S-100B and C reactive protein increased before symptoms or signs of encephalomyelitis and peaked when the patient fell into a coma. At that point, additional brain damage markers and peripheral T cell phenotype was analyzed. The analyses were repeated four times during the patient's recovery. Axonal damage marker neurofilament light polypeptide (NFL) and astrocytic damage marker glial fibrillar acidic protein (GFAP) were very high in blood and cerebrospinal fluid and gradually normalized after immunosuppression and intensive care. The costimulatory receptor inducible T cell costimulatory receptor (ICOS) was expressed on a high proportion of CD4+ and CD8+T cells as encephalomyelitis symptoms peaked and then gradually decreased in parallel with clinical improvement. Both single and double immune checkpoint inhibitor-treated melanoma patients with other serious immune-related adverse events (irAE) (n=9) also expressed ICOS on a significantly higher proportion of CD4+ and CD8+T cells compared with controls without irAE (n=12). In conclusion, our results suggest a potential role for ICOS on CD4+ and CD8+T cells in mediating encephalomyelitis and other serious irAE. In addition, brain damage markers in blood could facilitate early diagnosis of encephalitis.

RAB7L1 Participates in Secondary Brain Injury Induced by Experimental Intracerebral Hemorrhage in Rats.

RAB7, a member of RAS oncogene family-like 1 (RAB7L1), is a GTPase belonging to the Rab family and acts as an upstream regulator to regulate the kinase activity of leucine-rich repeat kinase 2 (LRRK2). Although LRRK2 has been shown to aggravate secondary brain injury (SBI) after intracerebral hemorrhage (ICH), it is unknown whether RAB7L1 is also involved in this process. The purpose of the present study was to investigate the role of RAB7L1 in ICH-induced SBI in vivo. Autologous blood was injected into adult male Sprague-Dawley rats to induce an ICH model in vivo. The results showed that the protein levels of RAB7L1 increased after ICH. Overexpression of RAB7L1 induced neuronal apoptosis and damage, as demonstrated by TUNEL-positive and FJB-positive cells, and exacerbated ICH-induced learning and cognitive dysfunctions; in contrast, downregulation of RAB7L1 via RNA interference yielded comparatively opposite changes in these parameters. In summary, this study demonstrates that RAB7L1 promotes SBI after ICH and may represent a potential target for ICH therapy.

Molecular genetics of alcohol-related brain damage.

AIMS: In the scientific literature it has been repeatedly hypothesized that there is a heritable susceptibility to thiamine deficiency comparable to other hereditary metabolic disorders. The aim of this paper is to review the most recent knowledge on the genetic susceptibility to the development of alcohol-related Wernicke-Korsakoff syndrome (WKS). METHODS: A literature review was carried out looking at the molecular genetics studies performed in alcohol-dependent patients affected by WKS. RESULTS: A genetic component in the pathogenesis of WKS has been postulated since the late seventies. Since then, very few genetic studies have been carried out on candidate genes such as thiamine-dependent enzymes, alcohol-metabolizing enzymes and GABA receptors. The findings are controversial and not conclusive. Several authors reported the important role of the thiamine transporters in the pathogenesis of the thiamine deficiency disorders. Our findings on SLC19A2 and SLC19A3 suggest a potential role of these two genes in the pathophysiology of alcohol-related thiamine deficiency but further studies need to be carried out. CONCLUSIONS: The WKS may be a very complex, multifactorial disorder where the interaction of multiple genes and environment plays an important role in the pathogenesis. However, it is still plausible that megaphenic gene effects are responsible for WKS susceptibility and the thiamine transport genes are good candidates for having such a role. Further genetic studies are definitely needed to investigate the association with candidate genes or linkage with hot spot areas.

Proteomics approach in the study of the pathophysiology of alcohol-related brain damage.

AIMS: Chronic, excessive drinking of alcohol can induce brain damage in the regions important for neurocognitive function. Some of the damage are permanent while some are appearantly reversible. It is our aim to understand the molecular mechanisms underlying alcohol-induced and/or related brain damage, particularly of that observed in 'medically uncomplicated' (without heptatic cirrhosis or Wernicke-Korsakoff Syndrome [WKS]) alcoholics. METHODS: A high-throughput proteomics technology has been applied to several 'alcohol-sensitive' brain regions from uncomplicated and hepatic cirrhosis-complicated alcoholics to understand the mechanisms of alcohol-related brain damage at the level of protein expression. RESULTS: It was clearly demonstrated that each brain region reacts in significantly different manner to chronic alcohol ingestion. Appearant abnormalities in vitamin B1 (thiamine)-related biochemical pathways were observed in several brain regions, such as the dorsolateral prefrontal cortex, genu (a frontal part of the corpus callosum) and cerebellar vermis in uncomplicated alcoholics, suggesting that the reduction of this important nutritional component might be associated with brain damage even without the signs of WKS. In addition, in the two different subregions of the corpus callosum (genu and splenium [a posterior part of the corpus callosum]) and the cerebellar vermis, significant differences in protein expression profiles between uncomplicated and complicated alcoholics with hepatic cirrhosis were identified, suggesting that hepatic factors such as ammonia have significant additive influences on brain protein expression, which might lead to the structural changes and/or damage in these brain regions. Furthermore, in the hippocampus, significant change of the level of glutamine synthetase expression was observed, suggesting once again the importance of ammonia as a cause of brain damage in this region. CONCLUSIONS: Although our data did not show any evidence of "direct" alcohol effects to induce the alteration of protein expression in association with brain damage, high-throughput neuroproteomics approaches are proven to have a potential to dissect the mechanisms of complex brain disorders.

Apolipoprotein E genotype in patients with cerebrovascular diseases and its effect on the disease outcome.

A total of 100 hospitalized stroke patients and 30 healthy controls were included in a study aiming to determine the predictive role of ApoE genotype polymorphism for stroke outcome in the Turkish population. The most frequent ApoE genotype was epsilon3/3 reflecting Asian population polymorphic distribution. ApoE polymorphism in the Eastern Turkish population was found to be independent of stroke type, OSCP subtypes of infarction, localization of hemorrhage, severity of carotid artery stenosis, and resultant stroke outcome. Distinct polymorphic results in populations from nearby regions suggest a multifactorial pathogenesis and presence of very complex genetic factors in the development of stroke and stroke outcome.

Neurological aspects of hyperinsulinism-hyperammonaemia syndrome.

Hyperinsulinism-hyperammonaemia syndrome (HHS) is a rare cause of congenital hyperinsulinism, due to missense mutations in the GLUD1 gene, resulting in glutamate dehydrogenase (GDH) overactivity. The aim of this study was to document the spectrum of neurological disturbances associated with HHS and to identify possible phenotype-genotype correlations. We retrospectively analyzed the neurological outcomes of 22 consecutive patients (12 males, 10 females) aged from 18 months to 40 years and diagnosed with HHS. We analyzed demographic and clinical features and neuroradiological, biochemical, and genetic findings. Fourteen patients had childhood-onset epilepsy. Learning disability was found in 17 patients. Two patients had pyramidal involvement and one had generalized dystonia. Seizures were observed in 11 of 19 patients with documented GLUD1 mutations, and nine of these 11 patients had a mutation in the guanosine triphosphate (GTP) binding site. Our data demonstrate that neurological disorders in HHS are more frequent than previously thought and might suggest that mutations in the GTP binding site of GDH could be associated with more frequent epilepsy.

Neurodevelopmental markers in different psychopathological dimensions of first episode psychosis: the ESPIGAS study.

OBJECTIVE: The main aim of this study was to explore whether specific groups of patients with first episode non-affective psychosis could be identified on a psychopathological basis and, then, whether such identified groups could be validated by exploring their correlation with a variety of neurodevelopmental markers. METHOD: Eighty-seven patients with a first episode of non-affective psychotic disorder were consecutively recruited. We assessed psychopathology and neurological soft signs using the PANSS and the Neurological Evaluation Scale, respectively. We collected information on obstetric complications, premorbid adjustment and family history. RESULTS: All PANSS symptoms were analysed using principal component analysis and four factors were obtained (negative, disorganization, positive and paranoid). Subsequently, the four factors were subjected to a cluster analysis where three groups emerged: "paranoid" (n=40), "low score" (n=29) and "negative" (n=18) subtype. After adjusting by sex and age, we found that the "negative group" had poorer social premorbid adjustment, worse verbal fluency and higher prevalence of both obstetric complications and neurological soft signs, when compared with the "low score" group. Similarly, the "negative group" showed significantly poorer social premorbid adjustment and higher number of neurological soft signs than the "paranoid group". CONCLUSIONS: Our results support that, among non-affective first onset psychotic patients, those with predominant negative symptoms are more likely to correlate with higher presence of neurodevelopmental markers.

[Epigenetic regulation in alcohol-related brain damage].

Ethanol is a deleterious agent that causes various kinds of neuronal damage to both the developing and adult brain. Recent research on alcoholism implicates impaired function of neural stem cell (NSC) in the pathogenesis of ethanol-induced brain dysfunction. We previously reported that the differentiation of NSCs into neurons was significantly influenced by ethanol. We also found that neuron-restrictive silencer factor/repressor element 1-silencing transcription factor (NRSF/ REST) binding activity potentiated by ethanol underlies the mechanism of ethanol inhibition of neuronal differentiation. Epigenetics refers to post-translational modifications of DNA and nuclear proteins that produce lasting alterations in patterns of gene expression. Epigenetic mechanism plays a critical role of neuronal plasticity and there is clear evidence that dysfunction of epigenetic mechanism also contributes to neurological and psychiatric illness. We will review epigenetic regulation in pathogenesis of psychiatric illness including alcoholism. We also demonstrated that trichostatin A, histone deacetylase inhibitor, reduced the ethanol-induced suppression of neuronal differentiation of NSCs. We suggest that ethanol alters the function of neural differentiation through the mechanism of potentiation of NRSF/REST binding and histone modifications.

Revisiting the legal standards that govern requests to sterilize profoundly incompetent children: in light of the "Ashley Treatment," is a new standard appropriate?

This Note discusses the recent controversy surrounding a six-year-old girl named Ashley, whose parents chose to purposefully stunt her growth and remove her reproductive organs for nonmedical reasons. A federal investigation determined that Ashley's rights had been violated because doctors performed the procedure, now referred to as the "Ashley Treatment," without first obtaining a court order. However, the investigation did not make any conclusions regarding whether the "Ashley Treatment" could present a legally permissible treatment option in the future. After discussing the constitutional rights that the "Ashley Treatment" implicates and the current legal standards in place, this Note examines how courts have applied these legal standards to cases involving extreme requests. Drawing upon legal commentators, this Note concludes that a court could approve a request for the "Ashley Treatment" in appropriate and limited cases where the parents have presented clear and convincing evidence before a court that the benefits that the "Ashley Treatment" would provide to the child and her family outweigh the risks associated with the procedure. This Note argues that those benefits may include extrinsic considerations, but courts should remain cautious when considering such evidence and be sure that the evidence as a whole supports their conclusions.

Spontaneously hypertensive rats are highly vulnerable to AMPA-induced brain lesions.

BACKGROUND AND PURPOSE: Whereas the effects of chronic arterial hypertension on the cerebral vasculature have been widely studied, its effects on brain tissue have been studied less so. Here we examined if spontaneously hypertensive rats (SHRs) or the normotensive control Wistar Kyoto rats (WKYs) made hypertensive by renal artery stenosis (R-WKYs) are vulnerable to an excitotoxic brain lesion provoked by an overactivation of glutamate receptors. METHODS: Lesion volumes were quantified by histology in WKYs and SHRs subjected to striatal administration of N-methyl-d-aspartate (NMDA) or alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA). The expression of AMPA receptors subunits and calcium/calmodulin kinase-II alpha was analyzed by real-time polymerase chain reaction and Western blot. RESULTS: NMDA (50 and 75 nmol) induced similar lesions in both SHRs (10+/-2 mm(3) and 16+/-4 mm(3), respectively) and WKYs (11+/-2 mm(3) and 19+/-7 mm(3), respectively). However, AMPA-induced (2.5 and 5 nmol) lesions were significantly greater in 14-week-old SHRs (14+/-3 mm(3) and 20+/-5 mm(3), respectively) than WKYs (4+/-2 mm(3), P<0.05 and 7+/-4 mm(3), P<0.001, respectively). Furthermore, normotensive 7-week-old SHRs also displayed an aggravated AMPA-induced lesion compared with age-matched WKYs (10+/-3 mm(3) vs 6+/-3 mm(3); P<0.05). Neither NMDA nor AMPA produced increased lesion volumes in R-WKYs (12+/-3 mm(3) and 5+/-4 mm(3), respectively) compared with WKYs. Striatal levels of AMPA receptors subunits, GluR1 and GluR2, were not different between SHRs and WKYs. However, SHRs displayed an increase in phosphorylated form of GluR1 at Ser-831 (P<0.05), as well as in calcium/calmodulin kinase-II alpha (P<0.002). Selective inhibition of this kinase by KN-93 reduced AMPA-induced damage in SHRs (P<0.01 vs vehicle). CONCLUSIONS: These findings show that an increase in phosphorylated GluR1, which increases AMPA receptor conductance, may be involved in the vulnerability of SHRs to AMPA.

Effect of kainic acid treatment on insulin-like growth factor-2 receptors in the IGF2-deficient adult mouse brain.

Insulin-like growth factor-2 (IGF2) is a member of the insulin gene family with known neurotrophic properties. The actions of IGF2 are mediated via the IGF type 1 and type 2 receptors as well as through the insulin receptors, all of which are widely expressed throughout the brain. Since IGF2 is up-regulated in the brain after injury, we wanted to determine whether the absence of IGF2 can lead to any alteration on brain morphology and/or in the response of its receptor binding sites following a neurotoxic insult. No morphological differences were observed between the brains of IGF2 knockout (IGF2(-/-)) and wild-type control (IGF2(+/+)) mice. However, our in vitro receptor autoradiography results indicate that IGF2(-/-) mice had lower endogenous levels of [(125)I]IGF1 and [(125)I]insulin receptor binding sites in the hippocampus and cerebellum as compared to IGF2(+/+) mice, while endogenous [(125)I]IGF2 receptor binding showed a decrease only in the cerebellum. Seven days after kainic acid administration, the [(125)I]insulin receptor binding sites were significantly decreased in all brain regions of the IGF2(+/+) mice, while the levels of [(125)I]IGF1 and [(125)I]IGF2 binding sites were decreased only in select brain areas. The IGF2(-/-) mice, on the other hand, showed increased [(125)I]IGF1 and [(125)I]IGF2 and [(125)I]insulin receptor binding sites in selected regions such as the hippocampus and cerebellum. These results, taken together, suggest that deletion of IGF2 gene does not affect gross morphology of the brain but does selectively alter endogenous [(125)I]IGF1, [(125)I]IGF2 and [(125)I]insulin receptor binding sites and their response to neurotoxicity.

Magnetic resonance imaging and magnetic resonance spectroscopy in isolated sulfite oxidase deficiency.

Isolated sulfite oxidase deficiency is a rare genetic neurometabolic disease. The first symptoms of this disorder (similar to symptoms of ischemic events) may lead to misdiagnosis and to subsequent birth of affected children in these families. This study characterizes the magnetic resonance (MR) imaging and (for the first time, to our knowledge) the MR spectroscopy features of isolated sulfite oxidase deficiency to provide a means for early and correct diagnosis. Three patients with isolated sulfite oxidase deficiency are studied who manifested intractable seizures and severe hypotonia in the immediate postnatal period with an unknown diagnosis, despite extensive workup. MR imaging and proton MR spectroscopy examinations were performed early in the neonatal period in 2 infants and after 5 months in the third infant. The prominent MR features were early cystic white matter damage, accompanied by profound cerebral atrophy in the third infant. Compared with hypoxic-ischemic disorder, MR findings in isolated sulfite oxidase deficiency demonstrate a more severe condition, without subsequent recovery. The MR spectroscopy studies indicate early onset of energetic and metabolic imbalance. Urine stick findings demonstrated high sulfite levels in 2 patients, and the final diagnosis was subsequently made based on molecular, biochemical, and genetic findings. Magnetic resonance imaging and MR spectroscopy measurements may help differentiate isolated sulfite oxidase deficiency from hypoxic-ischemic condition in patients in whom this diagnosis is not clinically suspected and may lead to further genetic antenatal inquiry that might prevent the birth of other infants affected with this severe and incurable congenital disease.

Oxidative stress after subarachnoid hemorrhage in gp91phox knockout mice.

BACKGROUND: Oxidative stress largely contributes to early brain injury after subarachnoid hemorrhage (SAH). One of the major sources of reactive oxygen species is NADPH oxidase, upregulated after SAH. We hypothesized that NADPH oxidase-induced oxidative stress plays a major causative role in early brain injury after SAH. METHODS: Using gp91phox knockout (ko) and wild-type (wt) mice, we studied early brain injury in the endovascular perforation model of SAH. Mortality rate, cerebral edema, oxidative stress, and superoxide production were measured at 24 h after SAH. Neurological evaluation was done at 23 h after SAH surgery. RESULTS: Genotyping confirmed the existence of a nonfunctional gp91phox gene in the ko mice. CBF measurements did not show differences in SAH-induced acute ischemia between ko and wt mice. SAH caused a significant increase of water content in the ipsilateral hemisphere as well as an increase of Malondialdehyde (MDA) levels and superoxide production. There were no significant differences in post-SAH mortality rate, brain water content and the intensity of the oxidative stress between knockout and wild type groups of mice. CONCLUSIONS: Our results suggest that gp91phox is not critically important to the early brain injury after SAH. An adaptive compensatory mechanism for free radical production in knockout mice is discussed.

Joint Effects of GWAS SNPs in Coagulation System Confer Risk to Hypertensive Intracerebral Hemorrhage.

Recent genome-wide association studies (GWAS) have identified numerous single nucleotide polymorphisms (SNPs) associated with coagulation system, including hemostatic factors and hematological phenotypes. However, few articles described the relationships between these SNPs and the risk of hemorrhagic stroke. The aim of our study was to evaluate the roles of these SNPs as risk factors and survival predictors for hemorrhagic stroke. Thirteen SNPs from GWAS in coagulation system were genotyped in a Chinese Han population including 1000 patients with hemorrhagic stroke (intracerebral hemorrhage, ICH = 743; subarachnoid hemorrhage, SAH = 257) and 1044 population-based controls. The associations between the genetics risk score (GRS) and risk of hemorrhagic stroke as well as post-stroke adverse outcomes were determined. No individual SNP was associated with the risk of hemorrhagic stroke. The GRS was calculated by summing the number of risk alleles of each SNP, and a total of 13 SNPs were included. Meanwhile, the GRS cutoffs values were defined to be close to quartiles or tertiles in control subjects. For quartiles, individuals with GRS about 8-9, 10-11, ≥12 had 1.28 (OR 1.28, 95% CI 0.98-1.68, p = 0.067)-, 1.36 (OR 1.36, 95% CI 1.04-1.79, p = 0.026)-, 1.53 (OR 1.53, 95% CI 1.13-2.07, p = 0.006)-fold increase in ICH risk compared to those with GRS ≤7, respectively; for tertiles, individuals with GRS about GRS 9-10, ≥11 had 0.98 (OR 0.98, 95% CI 0.78-1.23, p = 0.067)- and 1.26 (OR 1.26, 95% CI 1.00-1.59, p = 0.048)-fold increase in ICH risk compared to those with GRS ≤8, respectively. Further stratification analyses indicated that this association was only found in hypertensive ICH subjects. However, no statistical difference was found in the volume of hematoma, activities of daily living scale as well as hospital death in the ICH patients based on GRS values. Joint effects of SNPs associated with low coagulation factor levels might confer risk to ICH patients with hypertension. However, the clinical value on risk stratification and survival prediction was limited.

Stroke injury in rats causes an increase in activin A gene expression which is unaffected by oestradiol treatment.

Activins are members of the transforming growth factor-beta superfamily that exert neurotrophic and neuroprotective effects on various neuronal populations. To determine the possible function of activin in stroke injury, we assessed which components of the activin signalling pathway were modulated in response to middle cerebral artery occlusion (MCAO). Furthermore, because oestradiol replacement protects against MCAO-induced cell death, we explored whether oestradiol replacement influences activin gene expression. Female Sprague-Dawley rats underwent permanent MCAO and the expression of activins and their corresponding receptors was determined by semiquantitative reverse transcriptase-polymerase chain reaction at 24 h after onset of ischaemia. We observed up-regulation of activin betaA and activin type I receptor A mRNA in response to injury. Dual-label immunocytochemistry followed by confocal z-stack analysis showed that the activin A expressing cells comprised neurones. Next, we monitored the time course of activin betaA mRNA expression in oestradiol- or vehicle-treated rats at 4, 8, 16 and 24 h after MCAO via in situ hybridisation. Starting at 4 h after injury, activin betaA mRNA was up-regulated in cortical and striatal areas in the ipsilateral hemisphere. Activin betaA mRNA levels in the cortex increased dramatically with time and were highest at 24 h after the insult, and oestradiol replacement did not influence this increase.

Purinergic receptors modulate MAP kinases and transcription factors that control microglial inflammatory gene expression.

Following many types of brain injury, microglial cell hyperactivation, and the subsequent release of neurotoxic mediators into the CNS contributes to inflammation and neuronal death. Among the proteins important for modulating the inflammatory function of microglia are the P2 purinergic receptors for which extracellular adenine nucleotides, such as ATP, are ligands. Because adenine nucleotides are abundant in the extracellular fluid following brain injury, ATP may represent an important component of the inflammatory microenvironment controlling microglial cell function. Although much work has been done examining the mechanisms whereby adenine nucleotides stimulate inflammatory mediator production, little is known concerning their complementary inhibitory effects. In this review we will focus on what is currently known about the microglial inhibitory effects of adenine nucleotides in the context of inflammation and summarize the current knowledge of their effects via purinergic receptors on microglial signal transduction pathways including transcription factors important for controlling inflammatory gene expression. The relevance of these mechanisms to microglial inflammatory function and physiology will be discussed. Further, we present data here illustrating that MAP kinase signal transduction pathways are altered in activated microglia that have been primed with or co-exposed to adenine nucleotides; effects that are stimulus- and MAPK pathway-specific. We also demonstrate the ability of P2X7 receptors to stimulate the phosphorylation of CREB, a putative inhibitory transcription factor in microglia. Together, these data indicate that ATP may be an endogenous inhibitor or neuroprotective molecule decreasing the inflammatory capacity of microglia.