Chlorpromazine and loxapine reduce interleukin-1beta and interleukin-2 release by rat mixed glial and microglial cell cultures

Enzymatic Metabolic Switches of Astrocyte Response to Lipotoxicity as Potential Therapeutic Targets for Nervous System Diseases

Astrocytes play a pivotal role in maintaining brain homeostasis. Recent research has highlighted the significance of palmitic acid (PA) in triggering pro-inflammatory pathways contributing to neurotoxicity. Furthermore, Genomic-scale metabolic models and control theory have revealed that metabolic switches (MSs) are metabolic pathway regulators by potentially exacerbating neurotoxicity, thereby offering promising therapeutic targets. Herein, we characterized these enzymatic MSs in silico as potential therapeutic targets, employing protein-protein and drug-protein interaction networks alongside structural characterization techniques. Our findings indicate that five MSs (P00558, P04406, Q08426, P09110, and O76062) were functionally linked to nervous system drug targets and may be indirectly regulated by specific neurological drugs, some of which exhibit polypharmacological potential (e.g., Trifluperidol, Trifluoperazine, Disulfiram, and Haloperidol). Furthermore, four MSs (P00558, P04406, Q08426, and P09110) feature ligand-binding or allosteric cavities with druggable potential. Our results advocate for a focused exploration of P00558 (phosphoglycerate kinase 1), P04406 (glyceraldehyde-3-phosphate dehydrogenase), Q08426 (peroxisomal bifunctional enzyme, enoyl-CoA hydratase, and 3-hydroxyacyl CoA dehydrogenase), P09110 (peroxisomal 3-ketoacyl-CoA thiolase), and O76062 (Delta(14)-sterol reductase) as promising targets for the development or repurposing of pharmacological compounds, which could have the potential to modulate lipotoxic-altered metabolic pathways, offering new avenues for the treatment of related human diseases such as neurological diseases.

Induction of IL-2 by interleukin-12 p40 homodimer and IL-12, but not IL-23, in microglia and macrophages: Implications for multiple sclerosis

The level of IL-2 increases markedly in serum and central nervous system (CNS) of patients with multiple sclerosis (MS) and animals with experimental allergic encephalomyelitis (EAE). However, mechanisms by which IL-2 is induced under autoimmune demyelinating conditions are poorly understood. The present study underlines the importance of IL-12p40 homodimer (p402), the so-called biologically inactive molecule, in inducing the expression of IL-2 in mouse BV-2 microglial cells, primary mouse and human microglia, mouse peritoneal macrophages, RAW264.7 macrophages, and T cells. Interestingly, we found that p402 and IL-12p70 (IL-12), but not IL-23, dose-dependently induced the production of IL-2 and the expression of IL-2 mRNA in microglial cells. Similarly, p402 also induced the activation of IL-2 promoter in microglial cells and RAW264.7 cells. Among various stimuli tested, p402 was the most potent stimulus followed by IFN-γ, bacterial lipopolysaccharide, HIV-1 gp120, and IL-12 in inducing the activation of IL-2 promoter in microglial cells. Moreover, p402, but not IL-23, increased NFATc2 mRNA expression and the transcriptional activity of NFAT. Furthermore, induction of IL-2 mRNA expression by over-expression of p40, but not by p19, cDNA indicated that p40, but not p19, is responsible for the induction of IL-2 mRNA in microglia. Finally, by using primary microglia from IL to 12 receptor β1 deficient (IL-12Rβ1-/-) and IL-12 receptor β2 deficient (IL-12Rβ2-/-) mice, we demonstrate that p402 induces the expression of IL-2 via IL-12Rβ1, but not IL-12Rβ2. In experimental autoimmune encephalomyelitis, an animal model of MS, neutralization of p402 by mAb a3-1d led to decrease in clinical symptoms and reduction in IL-2 in T cells and microglia. These results delineate a new biological function of p402, which is missing in the so-called autoimmune cytokine IL-23, and raise the possibility of controlling increased IL-2 and the disease process of MS via neutralization of p402.

Neurodevelopmental and Neuropsychiatric Disorders

This chapter will focus on microglial involvement in neurodevelopmental and neuropsychiatric disorders, particularly autism spectrum disorder (ASD), schizophrenia and major depressive disorder (MDD). We will describe the neuroimmune risk factors that contribute to the etiopathology of these disorders across the lifespan, including both in early life and adulthood. Microglia, being the resident immune cells of the central nervous system, could play a key role in triggering and determining the outcome of these disorders. This chapter will review preclinical and clinical findings where microglial morphology and function were examined in the contexts of ASD, schizophrenia and MDD. Clinical evidence points out to altered microglial morphology and reactivity, as well as increased expression of pro-inflammatory cytokines, supporting the idea that microglial abnormalities are involved in these disorders. Indeed, animal models for these disorders found altered microglial morphology and homeostatic functions which resulted in behaviours related to these disorders. Additionally, as microglia have emerged as promising therapeutic targets, we will also address in this chapter therapies involving microglial mechanisms for the treatment of neurodevelopmental and neuropsychiatric disorders.

Methotrimeprazine is a neuroprotective antiviral in JEV infection via adaptive ER stress and autophagy

Japanese encephalitis virus (JEV) pathogenesis is driven by a combination of neuronal death and neuroinflammation. We tested 42 FDA-approved drugs that were shown to induce autophagy for antiviral effects. Four drugs were tested in the JE mouse model based on in vitro protective effects on neuronal cell death, inhibition of viral replication, and anti-inflammatory effects. The antipsychotic phenothiazines Methotrimeprazine (MTP) & Trifluoperazine showed a significant survival benefit with reduced virus titers in the brain, prevention of BBB breach, and inhibition of neuroinflammation. Both drugs were potent mTOR-independent autophagy flux inducers. MTP inhibited SERCA channel functioning, and induced an adaptive ER stress response in diverse cell types. Pharmacological rescue of ER stress blocked autophagy and antiviral effect. MTP did not alter translation of viral RNA, but exerted autophagy-dependent antiviral effect by inhibiting JEV replication complexes. Drug-induced autophagy resulted in reduced NLRP3 protein levels, and attenuation of inflammatory cytokine/chemokine release from infected microglial cells. Our study suggests that MTP exerts a combined antiviral and anti-inflammatory effect in JEV infection, and has therapeutic potential for JE treatment.

Treatment of Status Epilepticus after Traumatic Brain Injury Using an Antiseizure Drug Combined with a Tissue Recovery Enhancer Revealed by Systems Biology

We tested a hypothesis that in silico-discovered compounds targeting traumatic brain injury (TBI)-induced transcriptomics dysregulations will mitigate TBI-induced molecular pathology and augment the effect of co-administered antiseizure treatment, thereby alleviating functional impairment. In silico bioinformatic analysis revealed five compounds substantially affecting TBI-induced transcriptomics regulation, including calpain inhibitor, chlorpromazine, geldanamycin, tranylcypromine, and trichostatin A (TSA). In vitro exposure of neuronal-BV2-microglial co-cultures to compounds revealed that TSA had the best overall neuroprotective, antioxidative, and anti-inflammatory effects. In vivo assessment in a rat TBI model revealed that TSA as a monotherapy (1 mg/kg/d) or in combination with the antiseizure drug levetiracetam (LEV 150 mg/kg/d) mildly mitigated the increase in plasma levels of the neurofilament subunit pNF-H and cortical lesion area. The percentage of rats with seizures during 0-72 h post-injury was reduced in the following order: TBI-vehicle 80%, TBI-TSA (1 mg/kg) 86%, TBI-LEV (54 mg/kg) 50%, TBI-LEV (150 mg/kg) 40% (p < 0.05 vs. TBI-vehicle), and TBI-LEV (150 mg/kg) combined with TSA (1 mg/kg) 30% (p < 0.05). Cumulative seizure duration was reduced in the following order: TBI-vehicle 727 ± 688 s, TBI-TSA 898 ± 937 s, TBI-LEV (54 mg/kg) 358 ± 715 s, TBI-LEV (150 mg/kg) 42 ± 64 (p < 0.05 vs. TBI-vehicle), and TBI-LEV (150 mg/kg) combined with TSA (1 mg/kg) 109 ± 282 s (p < 0.05). This first preclinical intervention study on post-TBI acute seizures shows that a combination therapy with the tissue recovery enhancer TSA and LEV was safe but exhibited no clear benefit over LEV monotherapy on antiseizure efficacy. A longer follow-up is needed to confirm the possible beneficial effects of LEV monotherapy and combination therapy with TSA on chronic post-TBI structural and functional outcomes, including epileptogenesis.

Minocycline and antipsychotics inhibit inflammatory responses in BV-2 microglia activated by LPS via regulating the MAPKs/ JAK-STAT signaling pathway

BACKGROUND

Abnormal activation of microglia is involved in the pathogenesis of schizophrenia. Minocycline and antipsychotics have been reported to be effective in inhibiting the activation of microglia and thus alleviating the negative symptoms of patients with schizophrenia. However, the specific molecular mechanism by which minocycline and antipsychotics inhibit microglial activation is not clear. In this study, we aimed to explore the molecular mechanism of treatment effect of minocycline and antipsychotics on schizophrenia.

METHODS

Microglia cells were activated by lipopolysaccharide (LPS) and further treated with minocycline, haloperidol, and risperidone. Then cell morphology, specific marker, cytokines, and nitric oxide production process, and the proteins in related molecular signaling pathways in LPS-activated microglia were compared among groups.

RESULTS

The study found that minocycline, risperidone, and haloperidol significantly inhibited morphological changes and reduced the expression of OX-42 protein induced by LPS. Minocycline significantly decreased the production of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interleukin-1beta (IL-1β). Risperidone also showed significant decrease in the production of IL-6 and TNF-α, while haloperidol only showed significant decrease in the production of IL-6. Minocycline, risperidone, and haloperidol were found to significantly inhibit nitric oxide (NO) expression, but had no effect on inducible nitric oxide synthase (iNOS) expression. Both minocycline and risperidone were effective in decreasing the activity of c‑Jun N‑terminal kinase (JNK) and extracellular signal-regulated kinase (ERK) in the mitogen-activated protein kinases (MAPKs) signal pathway. Additionally, minocycline and risperidone were found to increase the activity of phosphorylated-p38. In contrast, haloperidol only suppressed the activity of ERK. Minocycline also suppressed the activation of janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), while risperidone and haloperidol only suppressed the activation of STAT3.

CONCLUSIONS

The results demonstrated that minocycline and risperidone exert stronger anti-inflammatory and neuroprotective effects stronger than haloperidol, through MAPKs and Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathways in BV2 cells stimulated with LPS, revealing the underlying mechanisms of minocycline and atypical antipsychotics in the treatment of negative schizophrenia symptoms.

Fifty years of experience with loxapine for the rapid non-coercive tranquilization of acute behavioral disturbances in schizophrenia patients, and beyond

INTRODUCTION

Acute behavioral disturbances in psychosis, including agitation, comprise a heterogeneous group of manifestations varying in intensity and duration they last for. They require rapid, non-coercive treatments ranging from verbal de-escalation to the calming effect of pharmacological agents. The treatment goals are reduction of patient suffering and prevention of disease deterioration. Stabilizing rather than sedating is preferred to ensure improved compliance and a stronger therapeutic alliance. Furthermore, animal pharmacology and clinical studies on agitation reveal the robust calming and anxiolytic properties of loxapine.

AREAS COVERED

This review covers the pharmacological and clinical history of loxapine along with research developments. It emphasizes the advantages of its multiple formulations ranging from injectable forms and tablets to orally inhaled forms to attain rapid and fine-tuned tranquilization.

EXPERT OPINION

Rapid tranquillization is achieved within 2-6 hours using liquid orally-consumed loxapine, and within an hour or less with its IM or orally inhaled forms. Loxapine has been adopted in the management of a wide range of acute disturbances, such as agitation in psychosis. In the context of personalized medicine, key cellular and molecular elements of the schizophrenia phenotype were recently shown to be improved with loxapine.

Chlorpromazine, a Clinically Approved Drug, Inhibits SARS-CoV-2 Nucleocapsid-Mediated Induction of IL-6 in Human Monocytes

The COVID-19 pandemic, caused by the rapidly spreading SARS-CoV-2 virus, led to the unprecedented mobilization of scientists, resulting in the rapid development of vaccines and potential pharmaceuticals. Although COVID-19 symptoms are moderately severe in most people, in some cases the disease can result in pneumonia and acute respiratory failure as well as can be fatal. The severe course of COVID-19 is associated with a hyperinflammatory state called a cytokine storm. One of the key cytokines creating a proinflammatory environment is IL-6, which is secreted mainly by monocytes and macrophages. Therefore, this cytokine has become a target for some therapies that inhibit its biological action; however, these therapies are expensive, and their availability is limited in poorer countries. Thus, new cheaper drugs that can overcome the severe infections of COVID-19 are needed. Here, we show that chlorpromazine inhibits the expression and secretion of IL-6 by monocytes activated by SARS-CoV-2 virus nucleocapsid protein and affects the activity of NF-κB and MEK/ERK signaling. Our results, including others, indicate that chlorpromazine, which has been used for several decades as a neuroleptic, exerts antiviral and immunomodulatory activity, is safe and inexpensive, and might be a desirable drug to support the therapy of patients with COVID-19.

Presenilin 2 N141I mutation induces hyperactive immune response through the epigenetic repression of REV-ERBα

Hyperimmunity drives the development of Alzheimer disease (AD). The immune system is under the circadian control, and circadian abnormalities aggravate AD progress. Here, we investigate how an AD-linked mutation deregulates expression of circadian genes and induces cognitive decline using the knock-in (KI) mice heterozygous for presenilin 2 N141I mutation. This mutation causes selective overproduction of clock gene-controlled cytokines through the DNA hypermethylation-mediated repression of REV-ERBα in innate immune cells. The KI/+ mice are vulnerable to otherwise innocuous, mild immune challenges. The antipsychotic chlorpromazine restores the REV-ERBα level by normalizing DNA methylation through the inhibition of PI3K/AKT1 pathway, and prevents the overexcitation of innate immune cells and cognitive decline in KI/+ mice. These results highlight a pathogenic link between this AD mutation and immune cell overactivation through the epigenetic suppression of REV-ERBα.

Hyperimmunity is associated with Alzheimer disease. Here the authors show that the Presenilin 2 N141I mutation causes overproduction of clock-controlled cytokines and memory deficits through suppression of REV-ERBα gene by hypermethylation.

Effects of Haloperidol, Risperidone, and Aripiprazole on the Immunometabolic Properties of BV-2 Microglial Cells

Microglial cells are resident macrophages in the brain that have been implicated in the pathophysiology of schizophrenia. There is a lack of studies covering the effects of antipsychotics on microglial cells. The current literature points to a possible anti-inflammatory action without clear mechanisms of action. The aim of this study is to characterize the effects of haloperidol, risperidone and aripiprazole on BV-2 microglial cells in in vitro conditions. We have used immunofluorescence and flow cytometry to analyze the classical pro and anti-inflammatory markers, while a real-time metabolic assay (Seahorse) was used to assess metabolic function. We analyzed the expression of p70S6K to evaluate the mTOR pathway activity with Western blot. In this study, we demonstrate the varying effects of haloperidol, risperidone and aripiprazole administration in BV-2 microglial cells. All three tested antipsychotics were successful in reducing the pro-inflammatory action of microglial cells, although only aripiprazole increased the expression of anti-inflammatory markers. Most significant differences in the possible mechanisms of action were seen in the real-time metabolic assays and in the mTORC1 signaling pathway activity, with aripiprazole being the only antipsychotic to reduce the mTORC1 activity. Our results shed some new light on the effects of haloperidol, risperidone and aripiprazole action in microglial cells, and reveal a novel possible mechanism of action for aripiprazole.

Changes in serum TNF-α, IL-18, and IL-6 concentrations in patients with chronic schizophrenia at admission and at discharge

OBJECTIVE

Schizophrenia is correlated with aberrant cytokine concentrations. The goal of our study was to detect the serum concentrations of tumor necrosis factor (TNF)-α, interleukin (IL)-18, and IL-6 concentrations in patients with chronic schizophrenia in the acute relapse state at admission and at discharge and to analyze the correlations between the three cytokine concentrations with psychosis symptoms.

METHODS

Enzyme-linked immunosorbent assay (ELISA) was used to analyze serum concentrations of TNF-α, IL-18, and IL-6 in 68 patients with chronic schizophrenia at admission and at discharge and in 80 controls. The Positive and Negative Syndrome Scale (PANSS) was used to analyze psychosis symptoms of the patients.

RESULTS

Serum concentrations of TNF-α, IL-18, and IL-6 in patients at admission were significantly elevated compared to those in controls. After treatment, IL-6 concentrations in patients at discharge were significantly reduced compared to those in patients at admission, and IL-6 concentrations showed no significant difference between patients at discharge and controls. In contrast, TNF-α and IL-18 concentrations showed no significant difference between patients at discharge and patients at admission, and TNF-α and IL-18 concentrations in patients at discharge were still significantly elevated compared to those in controls. IL-6 concentrations in patients at admission showed a positive correlation with negative scores, and IL-6 concentrations in patients at discharge showed positive correlations with positive, negative, and total scores. Reduction in IL-6 concentrations showed positive correlations with reduction in positive, negative, and total scores in patients at discharge.

CONCLUSION

Serum concentrations of TNF-α, IL-18, and IL-6 were significantly elevated in patients with chronic schizophrenia in the acute relapse state. After treatment, IL-6 concentrations in patients at discharge were significantly reduced compared to these in patients at admission.

Extended magnetic resonance imaging studies on the effect of classically activated microglia transplantation on white matter regeneration following spinal cord focal injury in adult rats

Spinal cord injuries are still a serious problem for regenerative medicine. Previous research has demonstrated that activated microglia accumulate in spinal lesions, influencing the injured tissues in various ways. Therefore, transplantation of activated microglia may have a beneficial role in the regeneration of the nervous system. The present study examined the influence of transplanted activated microglial cells in adult rats with injured spinal cords. Rats were randomly divided into an experimental (M) and control (C) group, and were subjected to non-laminectomy focal injury of spinal cord white matter by means of a high-pressured air stream. In group M, activated cultured microglial cells were injected twice into the site of injury. Functional outcome and morphological features of regeneration were analyzed during a 12-week follow-up. The lesions were characterized by means of magnetic resonance imaging (MRI). Neurons in the brain stem and motor cortex were labeled with FluoroGold (FG). A total of 12 weeks after surgery, spinal cords and brains were collected and subjected to histopathological and immunohistochemical examinations. Lesion sizes in the spinal cord were measured and the number of FG-positive neurons was counted. Rats in group M demonstrated significant improvement of locomotor performance when compared with group C (P<0.05). MRI analysis demonstrated moderate improvement in water diffusion along the spinal cord in the group M following microglia treatment, as compared with group C. The water diffusion perpendicular to the spinal cord in group M was closer to the reference values for a healthy spinal cord than it was in group C. The sizes of lesions were also significantly smaller in group M than in the group C (P<0.05). The number of brain stem and motor cortex FG-positive neurons in group M was significantly higher than in group C. The present study demonstrated that delivery of activated microglia directly into the injured spinal cord gives some positive effects for the regeneration of the white matter.

Bridging Autism Spectrum Disorders and Schizophrenia through inflammation and biomarkers - pre-clinical and clinical investigations

In recent years, evidence supporting a link between inflammation and neuropsychiatric disorders has been mounting. Autism spectrum disorders (ASD) and schizophrenia share some clinical similarities which we hypothesize might reflect the same biological basis, namely, in terms of inflammation. However, the diagnosis of ASD and schizophrenia relies solely on clinical symptoms, and to date, there is no clinically useful biomarker to diagnose or monitor the course of such illnesses.

The focus of this review is the central role that inflammation plays in ASD and schizophrenia. It spans from pre-clinical animal models to clinical research and excludes in vitro studies. Four major areas are covered: (1) microglia, the inflammatory brain resident myeloid cells, (2) biomarkers, including circulating cytokines, oxidative stress markers, and microRNA players, known to influence cellular processes at brain and immune levels, (3) effect of anti-psychotics on biomarkers and other predictors of response, and (4) impact of gender on response to immune activation, biomarkers, and response to anti-psychotic treatments.

Neuroprotection in Schizophrenia and Its Therapeutic Implications

Schizophrenia is a chronic and debilitating mental disorder. The persisting negative and cognitive symptoms that are unresponsive to pharmacotherapy reveal the impairment of neuroprotective aspects of schizophrenia. In this review, of the several neuroprotective factors, we mainly focused on neuroinflammation, neurogenesis, and oxidative stress. We conducted a narrative and selective review. Neuroinflammation is mainly mediated by pro-inflammatory cytokines and microglia. Unlike peripheral inflammatory responses, neuroinflammation has a role in various neuronal activities such as neurotransmission neurogenesis. The cross-talk between neuroinflammation and neurogenesis usually has beneficial effects in the CNS under physiological conditions. However, uncontrolled and chronic neuroinflammation exert detrimental effects such as neuronal loss, inhibited neurogenesis, and excessive oxidative stress. Neurogenesis is also a major component of neuroprotection. Adult neurogenesis mainly occurs in the hippocampal region, which has an important role in memory formation and processing. Impaired neurogenesis and an ineffective response to antipsychotics may be thought to indicate a deteriorating course of schizophrenia. Oxidative stress and excessive dopaminergic neurotransmission may create a vicious cycle and consequently disturb NMDA receptor-mediated glutamatergic neurotransmission. Based on the current evidences, several neuroprotective therapeutic approaches have been reported to be efficacious for improving psychopathology, but further longitudinal and large-sample based studies are needed.

Different influence of antipsychotics on the balance between pro- and anti-inflammatory cytokines depends on glia activation: An in vitro study

The microglial hypothesis of schizophrenia suggests that its neuropathology is closely associated with neuroinflammation manifested, inter alia, by an increased expression of cytokines. However, clinical investigations imply that schizophrenia is a heterogeneous disease and in some groups of patients the activated inflammatory process does not contribute to the disease-associated impairment of brain function. Clinical studies revealed also an equivocal impact of antipsychotics on peripheral and CSF cytokines, whereas experimental research performed on the stimulated glia cultures showed their inhibitory effect on pro-inflammatory cytokine levels. In the present study, the effect of chlorpromazine, haloperidol and risperidone (0.5, 5 or 10μM) on production of pro-inflammatory cytokines IL-1β and TNF-α and anti-inflammatory IL-10 was investigated in the unstimulated and lipopolysaccharide-stimulated primary rat mixed glial cell cultures. In the unstimulated cultures, haloperidol at all applied concentrations, risperidone at 5, 10μM and chlorpromazine at 10μM increased IL-10 levels in the culture supernatants without a significant influence on IL-1β or TNF-α levels, and all drugs applied at 10μM induced a robust increase in IL-10 mRNA expression. Under strong inflammatory activation, haloperidol and risperidone at all concentrations reduced production of both pro-inflammatory cytokines, without adverse effects on IL-10 expression when used at 10μM. Chlorpromazine at all concentrations diminished the production of three cytokines and did not induce anti-inflammatory effect. These results suggest that dependently on glia activation antipsychotics via different mechanisms may induce anti-inflammatory effect and that this activity is not common for all drugs under conditions of strong glia activation.

An Association Between Functional Polymorphisms of the Interleukin 1 Gene Complex and Schizophrenia Using Transmission Disequilibrium Test

IL1 gene complex has been implicated in the etiology of schizophrenia. To assess whether IL1 gene complex is associated with susceptibility to schizophrenia in Polish population we conducted family-based study. Functional polymorphisms from IL1A (rs1800587, rs17561, rs11677416), IL1B (rs1143634, rs1143643, rs16944, rs4848306, rs1143623, rs1143633, rs1143627) and IL1RN (rs419598, rs315952, rs9005, rs4251961) genes were genotyped in 143 trio with schizophrenia. Statistical analysis was performed using transmission disequilibrium test. We have found a trend toward an association of rs1143627, rs16944, rs1143623 in IL1B gene with the risk of schizophrenia. Our results show a protective effect of allele T of rs4251961 in IL1RN against schizophrenia. We also performed haplotype analysis of IL1 gene complex and found a trend toward an association with schizophrenia of GAGG haplotype (rs1143627, rs16944, rs1143623, rs4848306) in IL1B gene, haplotypes: TG (rs315952, rs9005) and TT (rs4251961, rs419598) in IL1RN. Haplotype CT (rs4251961, rs419598) in IL1RN was found to be associated with schizophrenia. After correction for multiple testing associations did not reach significance level. Our results might support theory that polymorphisms of interleukin 1 complex genes (rs1143627, rs16944, rs1143623, rs4848306 in IL1B gene and rs4251961, rs419598, rs315952, rs9005 in IL1RN gene) are involved in the pathogenesis of schizophrenia, however, none of the results reach significance level after correction for multiple testing.

A New Outlook on Mental Illnesses: Glial Involvement Beyond the Glue

Mental illnesses have long been perceived as the exclusive consequence of abnormalities in neuronal functioning. Until recently, the role of glial cells in the pathophysiology of mental diseases has largely been overlooked. However recently, multiple lines of evidence suggest more diverse and significant functions of glia with behavior-altering effects. The newly ascribed roles of astrocytes, oligodendrocytes and microglia have led to their examination in brain pathology and mental illnesses. Indeed, abnormalities in glial function, structure and density have been observed in postmortem brain studies of subjects diagnosed with mental illnesses. In this review, we discuss the newly identified functions of glia and highlight the findings of glial abnormalities in psychiatric disorders. We discuss these preclinical and clinical findings implicating the involvement of glial cells in mental illnesses with the perspective that these cells may represent a new target for treatment.

Association study of functional polymorphisms in interleukins and interleukin receptors genes: IL1A, IL1B, IL1RN, IL6, IL6R, IL10, IL10RA and TGFB1 in schizophrenia in Polish population

Schizophrenia has been associated with a large range of autoimmune diseases, with a history of any autoimmune disease being associated with a 45% increase in risk for the illness. The inflammatory system may trigger or modulate the course of schizophrenia through complex mechanisms influencing neurodevelopment, neuroplasticity and neurotransmission. In particular, increases or imbalance in cytokine before birth or during the early stages of life may affect neurodevelopment and produce vulnerability to the disease. A total of 27 polymorphisms of IL1N gene: rs1800587, rs17561; IL1B gene: rs1143634, rs1143643, rs16944, rs4848306, rs1143623, rs1143633, rs1143627; IL1RN gene: rs419598, rs315952, rs9005, rs4251961; IL6 gene: rs1800795, rs1800797; IL6R gene: rs4537545, rs4845617, rs2228145, IL10 gene: rs1800896, rs1800871, rs1800872, rs1800890, rs6676671; IL10RA gene: rs2229113, rs3135932; TGF1B gene: rs1800469, rs1800470; each selected on the basis of molecular evidence for functionality, were investigated in this study. Analysis was performed on a group of 621 patients with diagnosis of schizophrenia and 531 healthy controls in Polish population. An association of rs4848306 in IL1B gene, rs4251961 in IL1RN gene, rs2228145 and rs4537545 in IL6R with schizophrenia have been observed. rs6676671 in IL10 was associated with early age of onset. Strong linkage disequilibrium was observed between analyzed polymorphisms in each gene, except of IL10RA. We observed that haplotypes composed of rs4537545 and rs2228145 in IL6R gene were associated with schizophrenia. Analyses with family history of schizophrenia, other psychiatric disorders and alcohol abuse/dependence did not show any positive findings. Further studies on larger groups along with correlation with circulating protein levels are needed.

Grafted Activated Schwann Cells Support Survival of Injured Rat Spinal Cord White Matter

BACKGROUND AND OBJECTIVE

The influence of cultured Schwann cells on injured spinal cord in rats is examined.

METHODS

Focal injury of spinal cord white matter at the T10 level was produced using our original non-laminectomy method with a high-pressure air stream. Schwann cells from 7-day predegenerated rat sciatic nerves were cultured, transducted with green fluorescent protein and injected into the cisterna magna (experimental group) 3 times: immediately after spinal cord injury and 3 and 7 days later. Neurons in the brainstem and motor cortex were labeled with FluoroGold (FG) delivered caudally from the injury site a week before the end of the experiment. The functional outcome and morphologic features of neuronal survival were analyzed during a 12-week follow-up. The lesions were visualized and analyzed using magnetic resonance imaging. The maximal distance of expansion of implanted cells in the spinal cord was measured and the number of FG-positive neurons in the brain was counted.

RESULTS

Rats treated with Schwann cells presented significant improvement of locomotor performance and spinal cord morphology compared with the control group. The distance covered by Schwann cells was 7 mm from the epicenter of the injury. The number of brainstem and motor cortex FG-positive neurons in the experimental group was significantly higher than in the control group.

CONCLUSIONS

The data show that activated Schwann cells are able to induce the repair of injured spinal cord white matter. The route of application of cells via the cisterna magna seemed to be useful for their delivery in spinal cord injury therapy.

Glial cells as key players in schizophrenia pathology: recent insights and concepts of therapy

The past decade has witnessed an explosion of knowledge on the impact of glia for the neurobiological foundation of schizophrenia. A plethora of studies have shown structural and functional abnormalities in all three types of glial cells. There is convincing evidence of reduced numbers of oligodendrocytes, impaired cell maturation and altered gene expression of myelin/oligodendrocyte-related genes that may in part explain white matter abnormalities and disturbed inter- and intra-hemispheric connectivity, which are characteristic signs of schizophrenia. Earlier reports of astrogliosis could not be confirmed by later studies, although the expression of a variety of astrocyte-related genes is abnormal in psychosis. Since astrocytes play a key role in the synaptic metabolism of glutamate, GABA, monoamines and purines, astrocyte dysfunction may contribute to certain aspects of disturbed neurotransmission in schizophrenia. Finally, increased densities of microglial cells and aberrant expression of microglia-related surface markers in schizophrenia suggest that immunological/inflammatory factors are of considerable relevance for the pathophysiology of psychosis. This review describes current evidence for the multifaceted role of glial cells in schizophrenia and discusses efforts to develop glia-directed therapies for the treatment of the disease.

Cerebral regulatory T cells restrain microglia/macrophage-mediated inflammatory responses via IL-10

Forkhead box P3 (Foxp3)(+) regulatory T (Treg) cells maintain the immune tolerance and prevent inflammatory responses in the periphery. However, the presence of Treg cells in the CNS under steady state has not been studied. Here, for the first time, we show a substantial TCRαβ (+) CD4(+) Foxp3(+) T-cell population (cerebral Treg cells) in the rat cerebrum, constituting more than 15% of the cerebral CD4(+) T-cell compartment. Cerebral Treg cells showed an activated/memory phenotype and expressed many Treg-cell signature genes at higher levels than peripheral Treg cells. Consistent with their activated/memory phenotype, cerebral Treg cells robustly restrained the LPS-induced inflammatory responses of brain microglia/macrophages, suggesting a role in maintaining the cerebral homeostasis by inhibiting the neuroinflammation. In addition, brain astrocytes were the helper cells that sustained Foxp3 expression in Treg cells through IL-2/STAT5 signaling, showing that the interaction between astrocytes and Treg cells contributes to the maintenance of Treg-cell identity in the brain. Taken together, our work represents the first study to characterize the phenotypic and functional features of Treg cells in the rat cerebrum. Our data have provided a novel insight for the contribution of Treg cells to the immunosurveillance and immunomodulation in the cerebrum under steady state.

The role of pro-inflammatory cytokines in the neuroinflammation and neurogenesis of schizophrenia

Schizophrenia is a serious mental illness with chronic symptoms and significant impairment in psychosocial functioning. Although novel antipsychotics have been developed, the negative and cognitive symptoms of schizophrenia are still unresponsive to pharmacotherapy. The high level of social impairment and a chronic deteriorating course suggest that schizophrenia likely has neurodegenerative characteristics. Inflammatory markers such as pro-inflammatory cytokines are well-known etiological factors for psychiatric disorders, including schizophrenia. Inflammation in the central nervous system is closely related to neurodegeneration. In addition to pro-inflammatory cytokines, microglia also play an important role in the inflammatory process in the CNS. Uncontrolled activity of pro-inflammatory cytokines and microglia can induce schizophrenia in tandem with genetic vulnerability and glutamatergic neurotransmitters. Several studies have investigated the possible effects of antipsychotics on inflammation and neurogenesis. Additionally, anti-inflammatory adjuvant therapy has been under investigation as a treatment option for schizophrenia. Further studies should consider the confounding effects of systemic factors such as metabolic syndrome and smoking. In addition, the unique mechanisms by which pro-inflammatory cytokines are involved in the etiopathology of schizophrenia should be investigated. In this article, we aimed to review (1) major findings regarding neuroinflammation and pro-inflammatory cytokine alterations in schizophrenia, (2) interactions between neuroinflammation and neurogenesis as possible neural substrates for schizophrenia, and (3) novel pharmacological approaches.

Antipsychotics can modulate the cytokine profile in schizophrenia: attenuation of the type-2 inflammatory response

OBJECTIVE

We recently reported that the type-2 cytokine response is increased in schizophrenia. The aim of this study was to analyse the effects of antipsychotic drugs on the serum levels of type-1 (TNF-α, IFN-γ), type-2 (IL-4, IL-10), type-17 (IL-17) and regulatory cytokines (TGF-β, IL-27 and IL-6).

METHODS

Cytokine measurements in the patients were performed on day 0 and day 30 of the treatment using standard ELISA assays. Three groups of subjects were studied: patients that were unmedicated with First Episode Psychosis (FEP; n=88), patients that were treated with antipsychotics with Schizophrenia in relapse (SC in relapse; n=45) and healthy controls (n=36).

RESULTS

TGF-β levels were increased in both patient groups and were further enhanced after treatment in the FEP group (p=0.014) but not in the SC relapse group. Antipsychotic treatment was correlated with lower levels of IL-4, IL-6 and IL-27 (p<0.005) in the FEP group. Finally, the serum levels of IL-17 were not significantly altered between the two measurements but were significantly lower in the FEP group (p<0.001) when compared with healthy controls. After therapy, patients with SC who were in relapse had decreased serum levels of IL-4 (p=0.006) and IL-6 (p=0.007). We also observed a weak negative correlation between the IFN-γ/TGF-β ratio and the total PANSS score and between the IL-17/TGF-β ratio and the negative and general psychopathology subscales.

CONCLUSION

The increased type-2 cytokine serum levels in schizophrenia appear to be downregulated by antipsychotic treatment.

Neuroinflammation in schizophrenia especially focused on the role of microglia

An accumulating body of evidence point to the significance of neuroinflammation and immunogenetics also in schizophrenia. Recent genome-wide studies in schizophrenia suggest immune involvement in schizophrenia. Microglia are the resident macrophage of the brain and major players in innate immunity in the CNS. They respond rapidly to even minor pathological changes in the brain and may contribute directly to the neuronal degeneration by producing various pro-inflammatory cytokines and free radicals. In many aspects, the neuropathology of schizophrenia is closely associated with microglial activation. We and other researchers have shown the inhibitory effects of some typical or atypical antipsychotics on the release of inflammatory cytokines and free radicals from activated microglia, both of which are not only directly toxic to neurons but also cause a decrease in neurogenesis as well as white matter abnormalities in the brains of the patients with schizophrenia. The treatment through the inhibition of microglial activation may shed new light on the therapeutic strategy of schizophrenia.

Selective Neuronal and Brain Regional Expession of IL-2 in IL2P 8-GFP Transgenic Mice: Relation to Sensorimotor Gating

Brain-derived interleukin-2 (IL-2) has been implicated in diseases processes that arise during CNS development (e.g., autism) to neurodegenerative alterations involving neuroinflammation (e.g., Alzheimer’s disease). Progress has been limited, however, because the vast majority of current knowledge of IL-2’s actions on brain function and behavior is based on the use exogenously administered IL-2 to make inferences about the function of the endogenous cytokine. Thus, to identify the cell-type(s) and regional circuitry that express brain-derived IL-2, we used B6.Cg-Tg/ IL2-EGFP17Evr (IL2p8-GFP) transgenic mice, which express green fluorescent protein (GFP) in peripheral immune cells known to produce IL-2. We found that the IL2-GFP transgene was localized almost exclusively to NeuN-positive cells, indicating that the IL-2 is produced primarily by neurons. The IL2-GFP transgene was expressed in discrete nuclei throughout the rostral-caudal extent of the brain and brainstem, with the highest levels found in the cingulate, dorsal endopiriform nucleus, lateral septum, nucleus of the solitary tract, magnocellular/gigantocellular reticular formation, red nucleus, entorhinal cortex, mammilary bodies, cerebellar fastigial nucleus, and posterior interposed nucleus. Having identified IL-2 gene expression in brain regions associated with the regulation of sensorimotor gating (e.g., lateral septum, dorsal endopiriform nucleus, entorhinal cortex, striatum), we compared prepulse inhibition (PPI) of the acoustic startle response in congenic mice bred in our lab that have selective loss of the IL-2 gene in the brain versus the peripheral immune system, to test the hypothesis that brain-derived IL-2 plays a role in modulating PPI. We found that congenic mice devoid of IL-2 gene expression in both the brain and the peripheral immune system, exhibited a modest alteration of PPI. These finding suggest that IL2p8-GFP transgenic mice may be a useful tool to elucidate further the role of brain-derived IL-2 in normal CNS function and disease.

Inflammatory activation enhances NMDA-triggered Ca2+ signalling and IL-1β secretion in primary cultures of rat astrocytes

The aim of the present study was to measure the effects of NMDA receptor antagonists on rat astroglial-enriched primary cultures after incubation with lipopolysaccharide (LPS), with a view to explaining the role of NMDA receptors in the inflammatory activation of astrocytes. First, the presence of NMDA receptor subunits was confirmed at the protein level by immunocytochemical methods. The presence of functional NMDA receptors containing GluN2B subunits was then established by ratiometric fluorescent Ca(2+) imaging which revealed transient NMDA-triggered Ca(2+) responses. These responses could be blocked by the competitive antagonist 2-amino-5-phosphonopentoate (APV) and the non-competitive GluN2B subunit-selective antagonist ifenprodil. The NMDA-evoked Ca(2+) transients were dependent on Ca(2+) release from intracellular stores via interaction with InsP3-sensitive receptors as they were blocked by thapsigargin or xestospongin C. Following 24h incubation with LPS, astroglial inflammatory activation increased IL-1β secretion and NMDA-triggered Ca(2+) transients. The addition of APV or ifenprodil inhibited these enhanced responses, suggesting that LPS exposure stimulates IL-1β release from astrocytes through a mechanism that requires NMDA receptor stimulation.

Interleukin-2 and the septohippocampal system: intrinsic actions and autoimmune processes relevant to neuropsychiatric disorders

The effects of IL-2 on brain development, function, and disease are the result of IL-2's actions in the peripheral immune system and its intrinsic actions in the central nervous system (CNS). Determining whether, and under what circumstances (e.g., development, acute injury), these different actions of IL-2 are operative in the brain is essential to make significant advances in understanding the multifaceted affects of IL-2 on CNS function and disease, including psychiatric disorders. For several decades, there has been a great deal of speculation about the role of autoimmunity in brain disease. More recently, we have learned a great deal about the role of cytokines on neurobiological processes, and there have been many studies that have found peripheral immune alterations in patients with neurological and neuropsychiatric diseases. Despite a plethora of published literature, almost all of this data in humans is correlative and much of the basic research has understandably relied on simpler models (e.g., in vitro models). Good animal models such as our IL-2 knockout mouse model could provide valuable new insight into understanding how the complex biology of a cytokine such as IL-2 can have simultaneous, dynamic effects on multiple systems (e.g., regulating homeostasis in the brain and immune system, autoimmunity that can affect both systems). Animal models can also provide much needed new data elucidating neuroimmunological and autoimmune processes involved in brain development and disease. Such information may ultimately provide critical new insight into the role of brain cytokines and autoimmunity in prominent neurological and neuropsychiatric diseases (e.g., Alzheimer's disease, autism, multiple sclerosis, schizophrenia).

Interleukin-2 and the brain: dissecting central versus peripheral contributions using unique mouse models

Although many studies have documented peripheral immune alterations in patients with psychiatric and neurological disorders, almost all these data in humans are correlative. The actions of IL-2 on neurodevelopment, function, and disease are the result of both IL-2's actions in the peripheral immune system and intrinsic actions in the CNS. Determining if, and under what conditions (e.g., development, acute injury) these different actions of IL-2 are operative in the brain is essential to make advances in understanding the multifaceted affects of IL-2 on CNS function and disease. Mouse models have provided ways to obtain new insights into how the complex biology of a cytokine such as IL-2 can have simultaneous, dynamic effects on multiple systems (e.g., regulating homeostasis in the brain and immune system, autoimmunity that can affect both systems). Here we describe some of the relevant literature and our research using different mouse models. This includes models such as congenic IL-2 knockout mice bred on immunodeficient backgrounds coupled with immune reconstitution strategies used to dissect neuroimmunological processes involved in the development of septohippocampal pathology, and test the hypothesis that dysregulation of the brain's endogenous neuroimmunological milieu may occur with the loss of brain IL-2 gene expression and be involved in initiating CNS autoimmunity. Use of animal models like these in the field of psychoneuroimmunology may lead to critical advances into our understanding of the role of brain cytokines and autoimmunity in neurodegenerative diseases (e.g., Alzheimer's disease), neurodevelopmental disorder (e.g., autism, schizophrenia), and autoimmune diseases including multiple sclerosis.

Peripheral benzodiazepine receptors in patients with chronic schizophrenia: a PET study with [11C]DAA1106

Inflammatory/immunological process and glial contribution are suggested in the pathophysiology of schizophrenia. We investigated peripheral benzodiazepine receptors in brains of patients with chronic schizophrenia, which were reported to be located on mitochondria of glial cells, using [11C]DAA1106 with positron emission tomography. Fourteen patients and 14 age- and sex-matched normal controls participated in this study. PET data were analysed by two-tissue compartment model with metabolite-corrected plasma input. Clinical symptoms were assessed using the Positive and Negative Syndrome Scale. There was no significant difference between [11C]DAA1106 binding of the cortical regions of normal controls and patients with schizophrenia, whereas the patients showed a positive correlation between cortical [11C]DAA1106 binding and positive symptom scores. There was also a positive correlation between [11C]DAA1106 binding and duration of illness. Although the correlations need to be interpreted very cautiously, involvement of glial reaction process in the pathophysiology of positive symptoms or progressive change of schizophrenia might be suggested.

Metformin increases phagocytosis and acidifies lysosomal/endosomal compartments in AMPK-dependent manner in rat primary microglia

Recent evidence suggests that metformin shows beneficial effects in experimental models of neuroinflammatory diseases. The aim of the present study was to determine the effect of metformin on phagocytosis and acidification of lysosomal/endosomal compartments in rat primary microglia in the presence of lipopolysaccharide (LPS) and/or beta-peptides (25-35), (1-40), and (1-42). Metformin increased the phagocytosis of fluorescent microspheres in the presence or absence of all the beta-peptides. However, the drug had no effect on the phagocytosis in LPS-stimulated microglia regardless of the presence of all the beta-peptides. Metformin acidified the lysosomal/endosomal compartments in the presence or absence of the beta-peptide 1-40 in both resting and activated microglia. To elucidate the mechanism of metformin action, we used 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside as an activator of adenosine monophosphate-activated protein kinase (AMPK) and compound C as a confirmed pharmacological inhibitor of AMPK. We have shown that metformin increased AMPK activity in microglial cells and that all observed effects are AMPK-dependent because the pretreatment of microglia with compound C reversed the effects of the drug. Since degradation of proteins in lysosomal/endosomal compartments depends largely on their phagocytosis and acidification, metformin may be beneficial in proteinopathies affecting the brain.

Ambivalent effects of compound C (dorsomorphin) on inflammatory response in LPS-stimulated rat primary microglial cultures

It was proven that compound C displays beneficial effects in models of inflammatory-induced anemia, ischemic stroke, and fibrodysplasia ossificans progressiva. Compound C influence on microglia, playing a major role in neuroinflammation, has not been evaluated yet. The aim of the present study was to determine the effect of compound C on cytokine release, NO, and reactive oxygen species (ROS) production. The rat microglial cultures were obtained by shaking the primary mixed glial cultures. Cytokine and nitrite concentrations were assayed using ELISA kits. ROS were assayed with nitroblue tetrazolium chloride. AMPK activity was assayed using the SAMS peptide. The expression of arginase I, NF-kappaB p65, and hypoxia-inducible factor-1 alpha (HIF-1 alpha) was evaluated using Western blot. Compound C displayed ambivalent effect depending on microglia basal activity. It up-regulated the release of TNF alpha and NO production and increased the expression of arginase I in non-stimulated microglia. However, compound C down-regulated IL-1 beta, IL-6 and TNF alpha release, NO, ROS production, and AMPK activity, diminished NF-kappaB and HIF-1 alpha expression, as well as increased arginase I expression in lipopolysaccharide (LPS)-stimulated microglia. Compound C did not affect iNOS expression and IL-10 and TGF-beta release in non-stimulated and LPS-stimulated microglia. The observed alterations in the release or production of inflammatory mediators may be explained by the changes in NF-kappaB, HIF-1 alpha, and arginase I expression and 3-(4,5-dimethylthazol-2-yl)-2,5-diphenyltetrazolinum bromide values in response to LPS, whereas the basis for the compound C effect on non-stimulated microglia remains to be investigated.

Cholinergic protection via alpha7 nicotinic acetylcholine receptors and PI3K-Akt pathway in LPS-induced neuroinflammation

The present study was planned to investigate the effect of anti-cholinesterase drugs donepezil and neostigmine on neuroinflammation induced by intracerebroventricular administration of lipopolysaccharide (LPS, 50 microg) in rat. Proinflammatory cytokines (TNF-alpha and IL-1beta), expressions of iNOS and COX-2, acetylcholinesterase activity, malondialdehyde and reduced glutathione were studied in different brain regions at 24h of LPS injection. Donepezil was found to decrease the LPS-induced AChE activity and oxidative stress in all the brain regions. It also inhibited the LPS-induced proinflammatory cytokines and iNOS expression but did not affect the increased COX-2 expression whereas neostigmine treatment had no effect on LPS-induced proinflammatory cytokines. Methyllycaconitine (MLA), a alpha7 nicotinic acetylcholine receptor antagonist, significantly antagonized the donepezil mediated inhibition of LPS-induced proinflammatory cytokines, indicating that alpha7 nicotinic acetylcholine receptor subunit was playing a role in regulation of neuroinflammation. The phosphorylation of Akt, an effector of PI3K, increased with donepezil treatment. These results suggest that increased cholinergic activity in brain by donepezil prevents LPS-induced neuroinflammation via alpha7-nAChRs, followed by the PI3K-Akt pathway and this system may form the basis for the development of novel agents for reversing neuroinflammation or provide new indications for existing drugs.

Cytokines and schizophrenia: Microglia hypothesis of schizophrenia

The etiology of schizophrenia remains unclear, while there has been a growing amount of evidence for the neuroinflammation and immunogenetics, which are characterized by an increased serum concentration of several pro-inflammatory cytokines. Despite the fact that microglia comprise only <10% of the total brain cells, microglia respond rapidly to even minor pathological changes in the brain and may contribute directly to the neuronal degeneration by producing various pro-inflammatory cytokines and free radicals. In many aspects, the neuropathology of schizophrenia has recently been reported to be closely associatedwith microglial activation. Previous studies have shown the inhibitory effects of some typical/atypical antipsychotics on the release of inflammatory cytokines and free radicals from activated microglia, both of which have recently been known to cause a decrease in neurogenesis as well as white matter abnormalities in the brains of patients with schizophrenia. The microglia hypothesis of schizophrenia may shed new light on the therapeutic strategy for schizophrenia.

The antipsychotic spiperone attenuates inflammatory response in cultured microglia via the reduction of proinflammatory cytokine expression and nitric oxide production

Glial activation and neuroinflammatory processes play an important role in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and HIV dementia. Activated glia cells can secrete various proinflammatory cytokines and neurotoxic mediators, which may influence neuronal cell survival. Recent studies have demonstrated that glia cell-mediated neuroinflammation is also related to the pathophysiology of schizophrenia. In the present study, anti-inflammatory and neuroprotective effects of antipsychotics were investigated using cultured brain cells as a model. The results showed that spiperone significantly decreased the production of nitric oxide in lipopolysaccharide-stimulated BV-2 microglia cells, primary microglia and primary astrocyte cultures. Spiperone also significantly inhibited nitric oxide production in adenosine 5'-triphosphate (ATP)-stimulated primary microglia cultures. Spiperone markedly decreased the production of tumor necrosis factor-alpha in BV-2 microglia cells. Spiperone attenuated the expression of inducible nitric oxide synthase and proinflammatory cytokines such as interleukin-1beta and tumor necrosis factor-alpha at mRNA levels in BV-2 microglia cells. Spiperone inhibited nuclear translocation and DNA binding of the p65 subunit of nuclear factor kappa B (NF-kappaB), inhibitor of kappa B (IkappaB) degradation, and phosphorylation of p38 mitogen-activated protein kinase in the lipopolysaccharide-stimulated BV-2 microglia cells. Moreover, spiperone was neuroprotective, as the drug reduced microglia-mediated neuroblastoma cell death in the microglia/neuron co-culture. These results imply that the antipsychotic spiperone has anti-inflammatory and neuroprotective effects in the central nervous system by modulating glial activation.

Influence of LPS-induced neuroinflammation on acetylcholinesterase activity in rat brain

In the present study, neuroinflammation was induced by bilateral intracerebroventricular (ICV) administration of Lipopolysaccharide (LPS). Proinflammatory cytokines (TNF-alpha and IL-1beta), acetylcholinesterase (AChE) activity, malondialdehyde (MDA) and reduced glutathione (GSH) were studied as markers for neuroinflammation, cholinergic activity and oxidative stress respectively in different brain regions at different time points after LPS injection. LPS produced increase in proinflammatory cytokines, MDA and the decrease in level of GSH at 24 h indicating a state of inflammation in brain regions, which was significantly blocked by Ibuprofen, a non steroidal anti-inflammatory drug. Enhanced AChE activity with these inflammatory markers after LPS administration indicates a possible relationship between neuroinflammation and cholinergic system during the development of neurodegenerative diseases.

Comparative analysis of the expression of c-Fos and interleukin-2 proteins in hypothalamus cells during various treatments

The aim of the present work was to perform a combined analysis of the degree of activation of the anterior hypothalamus of the rat and expression of the interleukin-2 gene during treatments of different types: mild stress ("handling") and adaption to it, as well as intranasal administration of physiological saline and the peptides Vilon (Lys-Glu) and Epitalon (Ala-Glu-Asp-Gly). Changes in the numbers of c-Fos-and IL-2-positive cells in structures of the lateral area (LHA) and anterior (AHN), supraoptic (SON), and paraventricular (PVN) nuclei of the hypothalamus in Wistar rats. Ratios of the quantities of c-Fos-and IL-2-positive cells were determined in intact animals and after activation of brain cells initiated by different treatments; the influences of adaptation to handling on the nature of changes in the expression of these proteins was also studied. Combined analysis of the intensity of expression of these two proteins - c-Fos, a marker of neuron activation and a trans-factor for the IL-2 cytokine gene and other inducible genes, and IL-2 - in intact animals and after various treatments showed that the process of cell activation in most of the hypothalamic structures studied correlated with decreases in the quantity of IL-2-positive cells in these structures; different patterns of changes in the numbers of c-Fos-and IL-2-positive cells were seen in response to different treatments in conditions of stress and adaptation to it.

The effect of atypical antipsychotics, perospirone, ziprasidone and quetiapine on microglial activation induced by interferon-gamma

An accumulating body of evidences point to the significance of neuroinflammation and immunogenetics in schizophrenia, characterized by increased serum concentration of several pro-inflammatory cytokines. In the central nervous system (CNS), the microglial cells are the major immunocompetent cells which release pro-inflammatory cytokines, nitric oxide (NO) and reactive oxygen species to mediate the inflammatory process. In the present study, we investigated whether or not atypical antipsychotics, namely perospirone, quetiapine and ziprasidone, would have anti-inflammatory effects on the activated microglia which may potentiate neuroprotection. All three atypical antipsychotics significantly inhibited NO generation from activated microglia while perospirone and quetiapine significantly inhibited the TNF-alpha release from activated microglia. Antipsychotics, especially perospirone and quetiapine may have an anti-inflammatory effect via the inhibition of microglial activation, which is not only directly toxic to neurons but also has an inhibitory effect on neurogenesis and oligodendrogenesis, both of which have been reported to play a crucial role in the pathology of schizophrenia.

Immunological aspects in the neurobiology of suicide: elevated microglial density in schizophrenia and depression is associated with suicide

OBJECTIVES

Suicide has a high prevalence in patients with schizophrenia and affective disorder. Our recent postmortem study [Steiner J, Mawrin C, Ziegeler A, Bielau H, Ullrich O, Bernstein HG, Bogerts B. Distribution of HLA-DR-positive microglia in schizophrenia reflects impaired cerebral lateralization. Acta Neuropathologica (Berl) 2006;112:305-16.] revealed increased microglial densities in two schizophrenic patients who had committed suicide. Therefore, the hypothesis of microglial activation during acute psychosis was proposed. Alternatively, "suicide" could be a diagnosis-independent factor leading to microgliosis.

METHODS

To clarify this question, microglial HLA-DR expression was analyzed by immunohistochemistry in the dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), mediodorsal thalamus (MD) and hippocampus of 16 schizophrenics, 14 depressed patients with affective disorder and 10 matched controls. A subgroup of six schizophrenics and seven patients with affective disorder who committed suicide was included.

RESULTS

ANOVA revealed no effect of diagnosis on microglial density (DLPFC: P=0.469; ACC: P=0.349; MD: P=0.569; hippocampus: P=0.497). However, significant microgliosis was observed in the DLPFC (P=0.004), ACC (P=0.012) and MD (P=0.004) of suicide patients. A similar trend was seen in the hippocampus (P=0.057).

CONCLUSION

In conclusion, immunological factors may play a hitherto underestimated role in suicide. First, microglial activation might be interpreted as a consequence of presuicidal stress. Second, one might speculate a causal link between microglial activation and suicidal behaviour, such as neuroendocrine factors, cytokines, and nitric oxide, which are released from microglial cells and are known to modulate noradrenergic or serotonergic neurotransmission and thus may trigger suicidality.

Risperidone significantly inhibits interferon-gamma-induced microglial activation in vitro

Microglia has recently been regarded to be a mediator of neuroinflammation via the release of proinflammatory cytokines, nitric oxide (NO) and reactive oxygen species (ROS) in the central nervous system (CNS). Microglia has thus been reported to play an important role in the pathology of neurodegenerative disease, such as Alzheimer's disease (AD) and Parkinson's disease (PD). The pathological mechanisms of schizophrenia remain unclear while some recent neuroimaging studies suggest even schizophrenia may be a kind of neurodegenerative disease. Risperidone has been reported to decrease the reduction of MRI volume during the clinical course of schizophrenia. Many recent studies have demonstrated that immunological mechanisms via such as interferon (IFN)-gamma and cytokines might be relevant to the pathophysiology of schizophrenia. In the present study, we thus investigated the effects of risperidone on the generation of nitric oxide, inducible NO synthase (iNOS) expression and inflammatory cytokines: interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)-alpha by IFN-gamma-activated microglia by using Griess assay, Western blotting and ELISA, respectively. In comparison with haloperidol, risperidone significantly inhibited the production of NO and proinflammatory cytokines by activated microglia. The iNOS levels of risperidone-treated cells were much lower than those of the haloperidol-treated cells. Antipsychotics, especially risperidone may have an anti-inflammatory effect via the inhibition of microglial activation, which is not only directly toxic to neurons but also has an inhibitory effect on neurogenesis and oligodendrogenesis, both of which have been reported to play a crucial role in the pathology of schizophrenia.

Effect of anti-dementia drugs on LPS induced neuroinflammation in mice

Inflammation has been recently implicated in pathogenesis of dementia disorders. Effect of anti-dementia (Acetylcholinesterase inhibitor) drugs tacrine, rivastigmine and donepezil were studied on neuroinflammation induced by intraperitoneal administration of lipopolysaccharide (LPS) in mice. Interleukin-2 (IL-2) and isoforms of acetylcholinesterase (AChE) were estimated in different brain areas as marker for neuroinflammation and cholinergic activity respectively. LPS significantly increased the level of IL-2 in all the brain areas while enhancement of AChE activity varied in brain areas. It was found that administration of tacrine, rivastigmine and donepezil in mice significantly attenuated the LPS induced increased levels of IL-2 along with the significant reduction of AChE activity predominantly in salt soluble (SS) fraction as compared to the detergent soluble (DS) fraction in a dose dependent manner. In vitro effect of LPS was also studied in different brain areas. LPS significantly increased the AChE activity in SS fractions but the significant increase was not found in DS fractions. The present study indicate that cholinesterase inhibitor anti-dementia drugs are effective against LPS induced neuroinflammation that may be linked to enhanced cholinergic activity.

Cytokines in schizophrenia and the effects of antipsychotic drugs

Growing evidence suggests that the immune, endocrine, and nervous systems interact with each other through cytokines, hormones, and neurotransmitters. The activation of the cytokine systems may be involved in the neuropathological changes occurring in the central nervous system (CNS) of schizophrenic patients. Numerous studies report that treatment with antipsychotic drugs affects the cytokine network. Hence, it is plausible that the influence of antipsychotics on the cytokine systems may be responsible for their clinical efficacy in schizophrenia. This article reviews current data on the cytokine-modulating potential of antipsychotic drugs. First, basic information on the cytokine networks with special reference to their role in the CNS as well as an up-to-date knowledge of the cytokine alterations in schizophrenia is outlined. Second, the hitherto published studies on the influence of antipsychotics on the cytokine system are reviewed. Third, the possible mechanisms underlying antipsychotics' potential to influence the cytokine networks and the most relevant aspects of this activity are discussed. Finally, limitations of the presented studies and prospects of future research are delineated.

Distribution of HLA-DR-positive microglia in schizophrenia reflects impaired cerebral lateralization

Immunological alterations have been demonstrated in peripheral blood and cerebrospinal fluid of patients with schizophrenia, while previous postmortem studies have provided an inconsistent picture as to the role of microglia in the context of schizophrenia. Microglial activation is a sensitive indicator of changes in the CNS microenvironment, such as inflammatory and neurodegenerative processes. The aim of the present postmortem study was to examine HLA class II (HLA-DR) expression on microglia in brain regions which are particularly relevant for schizophrenia, with regard to hemispheric lateralization. Dorsolateral prefrontal cortex (DLPFC), anterior cingulate cortex (ACC), hippocampus and mediodorsal thalamus (MD) were studied in 16 cases with schizophrenia and 16 control subjects. Immunostaining was found in all brain regions and was not restricted to macrophage-like ameboid cells, but also appeared in ramified cells. Region-specific HLA-DR-positive cell density was not significantly different between cases with schizophrenia and controls. However, ameboid microglial cells were lateralized towards the right hemisphere in healthy subjects but not in the schizophrenia group (P=0.01). Postmortem interval correlated with ramified cell numbers in ACC/DLPFC (P=0.01/0.04) and ameboid cell density in hippocampus (P=0.03). Age, gender, duration of disease, medication dosage, storage delay and whole brain volume had no effect. Single case analysis revealed highly elevated microglial cell numbers in ACC and MD of two schizophrenic patients who had committed suicide during acute psychosis. In conclusion, the present data suggest the absence of microgliosis but decreased cerebral lateralization of ameboid microglia in schizophrenia.

Effect of chronic treatment with perazine on lipopolysaccharide-induced interleukin-1β levels in the rat brain

In the present study, we sought to determine whether chronic treatment with perazine alters lipopolysaccharide (LPS)-induced interleukin-1 beta (IL-1 beta) levels in the following rat brain regions: the hypothalamus, frontal cortex, striatum and hippocampus. Male Wistar rats were administered perazine dimaleate (15 or 30 mg/kg/day) in drinking water for 21 days. On day 22, LPS was injected i.p. (125 microg/kg) 2 h before decapitation. Concentrations of perazine and its metabolites in plasma and brain was assessed by HPLC. The levels of IL-1 beta were determined using ELISA. Treatment with perazine (30 mg/kg/day) reduced LPS-stimulated IL-1 beta levels in the hypothalamus, and a tendency to its decrease in the striatum and frontal cortex was observed. This in vivo study suggests for the first time that long-term oral administration of perazine modulates reactivity of cells producing IL-1 beta.