Effects of interferon-β on the cytokine production of astrocytes

Sebacic acid, a royal jelly-containing fatty acid, decreases LPS-induced IL-6 mRNA expression in differentiated human THP-1 macrophage-like cells

Macrophages produce many inflammatory mediators, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), in innate immune responses. However, excess production of these mediators by activated macrophages triggers deleterious effects, leading to disorders associated with inflammation. Royal jelly (RJ), a milky-white substance secreted by worker bees, contains unique fatty acids, including 10-hydroxy-2-decenoic acid (10H2DA) and sebacic acid (SA). 10H2DA has been reported to have various biological functions, such as anti-inflammation. However, the anti-inflammatory effect of SA is not fully understood. In this study, we investigated the effects of SA on lipopolysaccharide (LPS)-induced cytokine expression using differentiated human THP-1 macrophage-like cells. SA dose-dependently decreased LPS-induced mRNA expression of IL-6, but not TNF-α and IL-1β. SA suppressed the phosphorylation of signal transducers and activators of transcription 1 (STAT1) and STAT3, but hardly affected the activation of JNK, p38, or NF-κB. In addition, SA decreased LPS-induced interferon-β (IFN-β) expression, and the addition of IFN-β restored the inhibition by SA of LPS-induced STAT activation and IL-6 expression. Furthermore, SA suppressed LPS-induced nuclear translocation of interferon regulatory factor 3 (IRF3), a transcription factor responsible for IFN-β expression. Taken together, we conclude that SA selectively decreases LPS-induced expression of IL-6 mRNA through inhibition of the IRF3/IFN-β/STAT axis.

Type I IFN signaling in T regulatory cells modulates chemokine production and myeloid derived suppressor cells trafficking during EAE

Interferon-β has therapeutic efficacy in Multiple Sclerosis by reducing disease exacerbations and delaying relapses. Previous studies have suggested that the effects of type I IFN in Experimental Autoimmune Encephalomyelitis (EAE) in mice were targeted to myeloid cells. We used mice with a conditional deletion (cKO) of the type I IFN receptor (IFNAR) in T regulatory (Treg) cells to dissect the role of IFN signaling on Tregs. cKO mice developed severe EAE with an earlier onset than control mice. Although Treg cells from cKO mice were more activated, the activation status and effector cytokine production of CD4⁺Foxp3^- T cells in the draining lymph nodes (dLN) was similar in WT and cKO mice during the priming phase. Production of chemokines (CCL8, CCL9, CCL22) by CD4⁺Foxp3^- T cells and LN resident cells from cKO mice was suppressed. Suppression of chemokine production was accompanied by a substantial reduction of myeloid derived suppressor cells (MDSCs) in the dLN of cKO mice, while generation of MDSCs and recruitment to peripheral organs was comparable. This study demonstrates that signaling by type I IFNs in Tregs reduces their capacity to suppress chemokine production, with resultant alteration of the entire microenvironment of draining lymph nodes leading to enhancement of MDSC homing, and beneficial effects on disease outcome.

IFNβ Treatment Inhibits Nerve Injury-induced Mechanical Allodynia and MAPK Signaling By Activating ISG15 in Mouse Spinal Cord

Neuropathic pain is difficult to treat and remains a major clinical challenge worldwide. While the mechanisms which underlie the development of neuropathic pain are incompletely understood, interferon signaling by the immune system is known to play a role. Here, we demonstrate a role for interferon β (IFNβ) in attenuating mechanical allodynia induced by the spared nerve injury in mice. The results show that intrathecal administration of IFNβ (dosages up to 5,000 U) produces significant, transient, and dose-dependent attenuation of mechanical allodynia without observable effects on motor activity or feeding behavior, as is common with IFN administration. This analgesic effect is mediated by the ubiquitin-like protein interferon-stimulated gene 15 (ISG15), which is potently induced within the spinal cord following intrathecal delivery of IFNβ. Both free and conjugated ISG15 are elevated following IFNβ treatment, and this effect is increased in UBP43^-/- mice lacking a key deconjugating enzyme. The IFNβ-mediated analgesia reduces MAPK signaling activation following nerve injury, and this effect requires induction of ISG15. These findings highlight a new role for IFNβ, ISG15, and MAPK signaling in immunomodulation of neuropathic pain and may lead to new therapeutic possibilities. PERSPECTIVE: Neuropathic pain is frequently intractable in a clinical setting, and new treatment options are needed. Characterizing the antinociceptive potential of IFNβ and the associated downstream signaling pathways in preclinical models may lead to the development of new therapeutic options for debilitating neuropathies.

Anti-inflammatory and cognitive effects of interferon-β1a (IFNβ1a) in a rat model of Alzheimer's disease

Background

Aβ_1-42 peptide abnormal production is associated with the development and maintenance of neuroinflammation and oxidative stress in brains from Alzheimer disease (AD) patients. Suppression of neuroinflammation may then represent a suitable therapeutic target in AD. We evaluated the efficacy of IFNβ1a in attenuating cognitive impairment and inflammation in an animal model of AD.

Methods

A rat model of AD was obtained by intra-hippocampal injection of Aβ_1-42 peptide (23 μg/2 μl). After 6 days, 3.6 μg of IFNβ1a was given subcutaneously (s.c.) for 12 days. Using the novel object recognition (NOR) test, we evaluated changes in cognitive function. Measurement of pro-inflammatory or anti-inflammatory cytokines, reactive oxygen species (ROS), and SOD activity levels was performed in the hippocampus. Data were evaluated by one-way ANOVA with Fisher’s Protected Least Significant Difference (PLSD) test.

Results

We showed that treatment with IFNβ1a was able to reverse memory impairment and to counteract microglia activation and upregulation of pro-inflammatory cytokines (IL-6, IL-1β) in the hippocampus of Aβ_1-42-injected rats. The anti-inflammatory cytokine IL-10, significantly reduced in the Aβ_1-42 animals, recovered to control levels following IFNβ1a treatment. IFNβ1a also reduced ROS and lipids peroxidation and increased SOD1 protein levels in the hippocampus of Aβ_1-42-injected rats.

Conclusion

This study shows that IFNβ1a is able to reverse the inflammatory and cognitive effects of intra-hippocampal Aβ_1-42 in the rat. Given the role played by inflammation in AD pathogenesis and the established efficacy of IFNβ1a in the treatment of inflammatory diseases of the central nervous system such as multiple sclerosis, its use may be a viable strategy to inhibit the pro-inflammatory cytokine and oxidative stress cascade associated with Aβ deposition in the hippocampus of AD patients.

Ifit2 deficiency results in uncontrolled neurotropic coronavirus replication and enhanced encephalitis via impaired alpha/beta interferon induction in macrophages

Type I interferons (IFN-α/β) limit viral dissemination prior to the emergence of adaptive immune responses through the concerted action of interferon-stimulated genes (ISGs). Although IFN-α/β induction by coronaviruses is modest, it effectively limits viral spread within the central nervous system (CNS) and protects against mortality. The protective roles of specific ISGs against the mouse hepatitis virus (MHV) members of the coronaviruses are largely unknown. This study demonstrates a protective role of the ISG Ifit2 in encephalitis induced by the dual hepato- and neurotropic MHV-A59. Contrasting the mild encephalitis and 100% survival of MHV-A59-infected wild-type (wt) mice, nearly 60% of infected Ifit2(-/-) mice exhibited severe encephalitis and succumbed between 6 and 8 days postinfection. Increased clinical disease in Ifit2(-/-) mice coincided with higher viral loads and enhanced viral spread throughout the CNS parenchyma. Ifit2(-/-) mice also expressed significantly reduced IFN-α/β and downstream ISG mRNAs Ifit1, Isg15, and Pkr, while expression of proinflammatory cytokines and chemokines was only modestly affected in the CNS. Impaired IFN-α/β induction in the absence of Ifit2 was confirmed by ex vivo mRNA analysis of microglia and macrophages, the prominent cell types producing IFN-α/β following MHV CNS infection. Furthermore, both IFN-α/β mRNA and protein production were significantly reduced in MHV-infected Ifit2(-/-) relative to wt bone marrow-derived macrophages. Collectively, the data implicate Ifit2 as a positive regulator of IFN-α/β expression, rather than direct antiviral mediator, during MHV-induced encephalitis.

New lessons about old molecules: how type I interferons shape Th1/Th17-mediated autoimmunity in the CNS

Type I interferons (IFN-alpha and IFN-beta) were discovered more than five decades ago and are widely used for the treatment of human autoimmune diseases such as multiple sclerosis (MS). Despite their highly beneficial features, the precise mechanism of action remains speculative. Given the frequent side effects of IFN-alpha/beta therapy, understanding its action in an in vivo setting is vital to further improve this therapeutic approach. Major advances in our understanding of the IFN biology have recently been made and are particularly based on the combination of powerful genome-wide expression analysis in humans with gene-targeting techniques available for basic research. The recent discovery of a novel T-cell subset, Th17 cells, sheds new light on type I IFNs in MS.

Injury-induced type I IFN signaling regulates inflammatory responses in the central nervous system

Innate glial response is critical for the induction of inflammatory mediators and recruitment of leukocytes to sites of the injury in the CNS. We have examined the involvement of type I IFN signaling in the mouse hippocampus following sterile injury (transection of entorhinal afferents). Type I IFNs signal through a receptor (IFNAR), which involves activation of IFN regulatory factor (IRF)9, leading to the induction of IFN-stimulated genes including IRF7, that in turn enhances the induction of type I IFN. Axonal transection induced upregulation of IRF7 and IRF9 in hippocampus. Induction of IRF7 and IRF9 mRNAs was IFNAR dependent. Double-labeling immunofluorescence showed that IRF7 selectively was induced in Mac-1/CD11b(+) macrophages/microglia in hippocampus after axonal transection. IRF7 mRNA was also detected in microglia sorted by flow cytometry. Lack of type I IFN signaling resulted in increased leukocyte infiltration into the lesion-reactive hippocampus. Axonal lesion-induced CXCL10 gene expression was abrogated, whereas matrix metalloproteinase 9 mRNA was elevated in IFNAR-deficient mice. Our findings point to a role for type I IFN signaling in regulation of CNS response to sterile injury.

Arthritis and bursitis in multiple sclerosis patients treated with interferon‐beta

Interferon-beta (IFN-beta) is a type I interferon used in the management of multiple sclerosis. Therapy with IFN-beta has rarely been associated with the development of autoimmune disorders. We present the cases of two female patients diagnosed with relapsing-remitting multiple sclerosis (RRMS) who developed inflammatory musculoskeletal manifestations, following IFN-beta therapy. The first patient developed a monoarthritis 2 weeks after initiation of IFN-beta, which persisted during the 14 months of therapy and resolved with discontinuation of the medication. The second patient developed both autoimmune thyroid disease and a refractory pre-patellar bursitis after 50 months of IFN-beta therapy. Our literature review revealed an additional six cases of onset of inflammatory arthritis in MS patients receiving IFN-beta. We review these reports with comparison to our two cases. The role of IFN-beta in inflammatory musculoskeletal disease is unclear. The potential autoimmune complications of this therapeutic agent should be comprehended when monitoring patients receiving such treatment.

Effects of 1-bromopropane, a substitute for chlorofluorocarbons, on BDNF expression

1-Bromopropane (1-BP) has been widely used as an alternative to ozone-depleting chlorofluorocarbons in various industries. Although the neurotoxicity of 1-BP has been recently reported, there is little information about the effect of 1-BP on the cells in brain by experimental approach. Here we studied the effect of 1-BP on brain-derived neurotrophic factor (BDNF) expression in astrocytes in vitro. The BDNF mRNA level was remarkably decreased by 1-BP in a human astrocytoma cell line, U251, and in mouse primary astrocytes. The DNA-binding and specific reporter activity of cAMP response element-binding transcription factor (CREB), which is one of the key molecules regulating BDNF expression, were reduced by 1-BP in U251 and/or mouse primary astrocytes. Additionally, protein kinase A (PKA) activity was suppressed by 1-BP in U251. These results suggest that BDNF expression was affected by 1-BP through at least PKA.

Type I interferon receptor signalling is induced during demyelination while its function for myelin damage and repair is redundant

The type I interferons, interferon-beta and alpha (IFN-beta, IFN-alpha), are widely used for the treatment of autoimmune demyelination in the central nervous system (CNS). Their effects on de- and remyelination through the broadly expressed type I IFN receptor (IFNAR), however, are highly speculative. In order to elucidate the role of endogenous type I interferons for myelin damage and recovery we induced toxic demyelination in the absence of IFNAR1. We demonstrate that IFNAR signalling was induced during acute demyelination since the cytokine IFN-beta as well as the IFN-dependent genes IRF7, ISG15 and UBP43 were strongly upregulated. Myelin damage, astrocytic and microglia response, however, were not significantly reduced in the absence of IFNAR1. Furthermore, motor skills of IFNAR1-deficient animals during non-immune demyelination were unaltered. Finally, myelin recovery was found to be independent from endogenous IFNAR signalling, indicating a redundant role of this receptor for non-inflammatory myelin damage and repair.

Expression and functional significance of SOCS-1 and SOCS-3 in astrocytes

Astrocytes play a number of important physiological roles in CNS homeostasis. Inflammation stimulates astrocytes to secrete cytokines and chemokines that guide macrophages/microglia and T cells to sites of injury/inflammation. Herein, we describe how these processes are controlled by the suppressor of cytokine signaling (SOCS) proteins, a family of proteins that negatively regulate adaptive and innate immune responses. In this study, we describe that the immunomodulatory cytokine IFN-beta induces SOCS-1 and SOCS-3 expression in primary astrocytes at the transcriptional level. SOCS-1 and SOCS-3 transcriptional activity is induced by IFN-beta through IFN-gamma activation site (GAS) elements within their promoters. Studies in STAT-1alpha-deficient astrocytes indicate that STAT-1alpha is required for IFN-beta-induced SOCS-1 expression, while STAT-3 small interfering RNA studies demonstrate that IFN-beta-induced SOCS-3 expression relies on STAT-3 activation. Specific small interfering RNA inhibition of IFN-beta-inducible SOCS-1 and SOCS-3 in astrocytes enhances their proinflammatory responses to IFN-beta stimulation, such as heightened expression of the chemokines CCL2 (MCP-1), CCL3 (MIP-1alpha), CCL4 (MIP-1beta), CCL5 (RANTES), and CXCL10 (IP-10), and promoting chemotaxis of macrophages and CD4(+) T cells. These results indicate that IFN-beta induces SOCS-1 and SOCS-3 in primary astrocytes to attenuate its own chemokine-related inflammation in the CNS.

Distinct and nonredundant in vivo functions of IFNAR on myeloid cells limit autoimmunity in the central nervous system

The action of type I interferons in the central nervous system (CNS) during autoimmunity is largely unknown. Here, we demonstrate elevated interferon beta concentrations in the CNS, but not blood, of mice with experimental autoimmune encephalomyelitis (EAE), a model for CNS autoimmunity. Furthermore, mice devoid of the broadly expressed type I IFN receptor (IFNAR) developed exacerbated clinical disease accompanied by a markedly higher inflammation, demyelination, and lethality without shifting the T helper 17 (Th17) or Th1 cell immune response. Whereas adoptive transfer of encephalitogenic T cells led to enhanced disease in Ifnar1(-/-) mice, newly created conditional mice with B or T lymphocyte-specific IFNAR ablation showed normal EAE. The engagement of IFNAR on neuroectodermal CNS cells had no protective effect. In contrast, absence of IFNAR on myeloid cells led to severe disease with an enhanced effector phase and increased lethality, indicating a distinct protective function of type I IFNs during autoimmune inflammation of the CNS.

Interferon-beta protects astrocytes against tumour necrosis factor-induced apoptosis via activation of p38 mitogen-activated protein kinase

Several large clinical trials have demonstrated that interferon-beta (IFN-beta) therapy is effective in the treatment of multiple sclerosis (MS) patients. However, the mechanisms underlying the beneficial effects of IFN-beta are not fully understood. Most of the effort in the study of the relevant mechanisms of IFN-beta has dealt with its immunomodulatory actions. However, the beneficial effects of IFN-beta in MS patients may also depend on non-immune mechanisms, including the modulation of astrocyte function. In the present work, we have found that IFN-beta treatment protects astrocytes against tumour necrosis factor-induced apoptosis via activation of p38 mitogen-activated protein kinase. We propose that this effect may be of importance to protect astrocytes against apoptosis within the demyelinated plaques of the MS.

Induction of prostaglandin E2 synthesis and microsomal prostaglandin E synthase–1 expression in murine microglia by glioma-derived soluble factors

Object

Microglia are one of the members of monocyte/macrophage lineage in the central nervous system (CNS) and exist as ramified microglia in a normal resting state, but they are activated by various stimuli, such as tumors. Activated microglia induce immune responses in the CNS, but the precise functions of microglia in glioma microenvironments are not clear. It has been reported that glioma cells produce prostaglandin (PG)E2, which promotes the growth of tumor cells and possesses immunosuppressive activity. The authors previously reported that PGE2 production by peritoneal macrophages was enhanced by glioma-derived soluble factors, which induce an immunosuppressive state. In this study, they investigated PGE2 production by microglia treated with glioma cells and assessed the role of microglia in glioma microenvironments in the mouse.

Methods

Microglia and peritoneal macrophages were cultured in vitro with or without lipopolysaccharide, and tumor necrosis factor (TNF) and PGE2 in the culture supernatant were measured using L929 bioassay and enzyme immunoassay. The expression of mRNA was measured using reverse transcriptase polymerase chain reaction, and the protein expression was assayed with Western blotting. In some experiments glioma cells and conditioned glioma medium were added to the microglia cultures.

Results

Glioma cells studied in this report did not produce a significant amount of PGE2. However, the coculture of microglia with glioma cells or conditioned glioma medium led to the production of a large amount of PGE2. The enhancement of PGE2 production by microglia was more significant than that by peritoneal macrophages. The expression of cyclooxygenase (COX)–2 and particularly the expression of microsomal PGE synthase (mPGES)–1 (a terminal enzyme of the arachidonate cascade) in microglia were enhanced by conditioned glioma medium. The enhancement of mPGES-1 expression in microglia was more significant than that in peritoneal macrophages. The production of TNF was suppressed when culturing microglia with conditioned glioma medium, but this suppression was abrogated by the addition of a COX inhibitor (NS-398) and a PGE2 receptor (EP4) antagonist. Furthermore, TNF production was not suppressed in microglia from mPGES-1–deficient mice.

Conclusions

These results indicate that PGE2 production by microglia is enhanced by conditioned glioma medium, which induces an immunosuppressive state in the CNS. Therefore, the manipulation of microglia, from the standpoint of PGE2, provides investigators with an important strategy to induce an effective antiglioma immune response.

Lack of interferon-beta leads to accelerated remyelination in a toxic model of central nervous system demyelination

Interferon-beta (IFN-beta) is a pleiotropic cytokine that is known to modulate the immune response in multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS). Spontaneous remyelination and repair mechanisms in MS are mostly insufficient and contribute to clinical disability. Here, we investigated whether IFN-beta has a potential in modifying the extent of de- and remyelination in a toxic model of CNS demyelination induced by the copper chelator cuprizone. IFN-beta deficient (k/o) mice showed an accelerated spontaneous remyelination. However, the amount of remyelination after 6 weeks did not differ between the two groups. Demyelination in IFN-beta k/o mice was paralleled by a diminished astrocytic and microglia response as compared with wildtype controls, whereas the accelerated remyelination was paralleled by an increased number of oligodendrocyte precursor cells (OPC) within the demyelinated lesion at the beginning of the remyelination phase. We hypothesize that the absence of IFN-beta leads to more efficient recruitment and proliferation of OPC already during demyelination, thus allowing early remyelination. These results demonstrate that IFN-beta is able to alter remyelination in the absence of an immune-mediated demyelination.

Novel interferon-beta-induced gene expression in peripheral blood cells

Type I IFNs are used for treating viral, neoplastic, and inflammatory disorders. The protein products encoded by IFN-stimulated genes (ISGs) likely mediate clinical effects of IFN in patients. Macroarray assays, used for studying ISG induction in IFN-treated patients, comprise genes identified predominantly through analysis of long-term cell lines. To discover genes induced selectively by IFN-beta in PBMC, we exposed whole blood to physiological concentrations of IFN-beta. PBMC were prepared, and RNA was extracted, reverse-transcribed, and hybridized to cDNA microarrays, and microarray analysis identified 39 ISGs and 20 IFN-repressed genes (IRGs). Thirty-three ISGs were known previously, and six ISGs were novel. New ISGs included GTP cyclohydrolase 1; hypothetical protein LOC129607; hypothetical protein FLJ38348; leucine aminopeptidase 3; squalene epoxidase; and GTP-binding protein overexpressed in skeletal muscle. Twenty IRGs included IL-1beta and CXCL8, which had been identified earlier. CXCL1 was a novel IRG identified in the current study. PCR analysis demonstrated the regulation of six novel ISGs and CXCL1 as an IRG in PBMC and astrocytoma cells. Results were validated using RNA obtained ex vivo from blood of patients after injection with IFN-beta. Identification of new ISGs and IRGs in primary PBMC will enhance macroarray assays for monitoring IFN responsiveness.

Multifunctional effects of bradykinin on glial cells in relation to potential anti-inflammatory effects

Kinins have been reported to be produced and act at the site of injury and inflammation. Despite many reports that they are likely to initiate a particular cascade of inflammatory events, bradykinin (BK) has anti-inflammatory effects in the brain mediated by glial cells. In the present review, we have attempted to describe the complex responses and immediate reaction of glial cells to BK. Glial cells express BK receptors and induce Ca(2+)-dependent signal cascades. Among them, production of prostaglandin E(2) (PGE(2)), via B(1) receptors in primary cultured microglia, has a negative feedback effect on lipopolysaccharide (LPS)-induced release of tumor necrosis factor-alpha (TNF-alpha) via increasing intracellular cyclic adenosine monophosphate (cAMP). In addition, BK up-regulates the production of neurotrophic factors such as nerve growth factor (NGF) via B(2) receptors in astrocytes. These results suggest that BK may have anti-inflammatory and neuroprotective effects in the brain through multiple functions on glial cells. These observations may help to understand the paradox on the role of kinins in the central nervous system and may be useful for therapeutic strategy.

Entzündliche Erkrankungen des ZNS sowie immunmodulatorische Therapie und ihr Einfluss auf primäre Kopfschmerzen

Headaches are a well known symptom in systemic or local inflammatory diseases such as pneumonia or meningitis. These headaches may mimic primary headaches and are thought to be generated by inflammatory mediators acting directly on nociceptors or indirectly - via facilitation of neurons. Apart from prostaglandin and nitric oxide also cytokines (TNF-alpha or interleukin-6) may play a role. In primary headaches such as migraine inflammatory mechanisms also have been acclaimed to contribute to pain generation. The recently observed increase of migraine attacks under immunmodulatory therapy in multiple sclerosis has focussed attention on primary headaches in states of altered immunity, for instance in autoimmune disorders like lupus erythematosus, rheumatoid arthritis, or in patients treated with immunosuppressants. This article describes the standard of knowledge and tries to shed light on possible mechanisms of pain generation in the respective conditions.

Inflammation and cancer: How hot is the link?

Although inflammation has long been known as a localized protective reaction of tissue to irritation, injury, or infection, characterized by pain, redness, swelling, and sometimes loss of function, there has been a new realization about its role in a wide variety of diseases, including cancer. While acute inflammation is a part of the defense response, chronic inflammation can lead to cancer, diabetes, cardiovascular, pulmonary, and neurological diseases. Several pro-inflammatory gene products have been identified that mediate a critical role in suppression of apoptosis, proliferation, angiogenesis, invasion, and metastasis. Among these gene products are TNF and members of its superfamily, IL-1alpha, IL-1beta, IL-6, IL-8, IL-18, chemokines, MMP-9, VEGF, COX-2, and 5-LOX. The expression of all these genes are mainly regulated by the transcription factor NF-kappaB, which is constitutively active in most tumors and is induced by carcinogens (such as cigarette smoke), tumor promoters, carcinogenic viral proteins (HIV-tat, HIV-nef, HIV-vpr, KHSV, EBV-LMP1, HTLV1-tax, HPV, HCV, and HBV), chemotherapeutic agents, and gamma-irradiation. These observations imply that anti-inflammatory agents that suppress NF-kappaB or NF-kappaB-regulated products should have a potential in both the prevention and treatment of cancer. The current review describes in detail the critical link between inflammation and cancer.

Beneficial effect of interferon-β treatment in patients with multiple sclerosis is associated with transient increase in serum IL-6 level in response to interferon-β injection

In order to predict the clinical benefit of interferon-beta (IFN-beta) to patients with multiple sclerosis (MS), the following markers were investigated; (1) chronological change of cytokines (IFN-gamma, TNF-alpha, IL-6, IL-10, and TGF-beta) after administration of IFN-beta, (2) untoward effects of IFN-beta such as headache and arthralgia, (3) backgrounds of the patients such as age and relapse rate, (4) efficacy of IFN-beta therapy assessed by the change of relapse rate and progression of disability. Chronological blood sampling was performed 0, 10, and 24 h after injection of IFN-beta. The increase of serum IL-6 level in response to IFN-beta administration was associated with headache, arthralgia, relapse rate before treatment, and disability score at the initiation of the therapy. Significant association of change of serum TNF-alpha with age and headache was also observed. The important finding in this study was that patients with a transient increase in IL-6 in response to IFN-beta showed a slow disease progression. This result suggests that this transient increase in the serum IL-6 predicts favorable response to IFN-beta treatment.

Effects of interferon-beta on oligodendroglial cells

The effect of interferon-beta (IFN-beta) for the treatment of multiple sclerosis (MS) is thought to be mediated by the modulation of immune cells. In addition, it has been shown that glial cells may be influenced by IFN-beta and a role during remyelination has been suggested. However, the mechanism is not yet clear and there are conflicting data. We have therefore systematically investigated proliferation, differentiation, toxicity, and cytoprotection of IFN-beta on oligodendroglia, both as a direct effect and mediated indirectly via other glial cells. Differentiation of oligodendrocyte progenitor cells (OPC) was significantly (p<0.01) inhibited by IFN-beta only when cultured in the presence with astrocytes and microglia. Proliferation was not changed, neither was IFN-beta toxic. There was no cytoprotective effect of IFN-beta on oligodendroglia injury induced by H2O2, NO, complement, or glutamate. Similarly, there was no cytoprotective effect mediated via treatment of astrocytes with IFN-beta. These data demonstrate that IFN-beta is neither toxic nor cytoprotective for oligodendrocytes. In summary, the only effect of IFN-beta was the inhibition of differentiation of OPC mediated indirectly via other glial cells. In vivo experiments will show how this effect may influence remyelination.

Acetylcholinesterase Activity in Rats Experimentally Demyelinated with Ethidium Bromide and Treated with Interferon Beta

The ethidium bromide (EB) demyelinating model was associated with interferon beta (IFN-beta) to evaluate acetylcholinesterase (AChE) activity in the striatum (ST), hippocampus (HP), cerebral cortex (CC), cerebellum (CB), hypothalamus (HY), pons (PN) and synaptosomes from the CC. Rats were divided into four groups: I control (saline), II (IFN-beta), III (EB) and IV (EB and IFN-beta). After 7, 15 and 30 days rats (n = 6) were sacrificed, and the brain structures were removed for enzymatic assay. AChE activity was found to vary in all the brain structures in accordance with the day studied (7-15-30 days) (P < 0.05). In the group III, there was an inhibition of the AChE activity in the ST, CB, HY, HP and also in synaptosomes of the CC (P < 0.05). It was observed that IFN-beta per se was capable to significantly inhibit (P < 0.05) AChE activity in the ST, HP, HY and synaptosomes of the CC. Our results suggest that one of the mechanisms of action of IFN-beta is through the inhibition of AChE activity, and EB could be considered an inhibitor of AChE activity by interfering with cholinergic neurotransmission in the different brain regions.

1-BP inhibits NF-kappaB activity and Bcl-xL expression in astrocytes in vitro and reduces Bcl-xL expression in the brains of rats in vivo

1-Bromopropane (1-BP) has been widely used as a substitute for chlorofluorocarbon that destroys the ozone layer. Although the central neurotoxicity of 1-BP has been recently reported, a molecular mechanism is not clear. In particular, the effects on cells in brain have not been fully analyzed. Here, we studied the effects of 1-BP on the activation of transcription factors involved in anti-apoptotic function or cell survival in astrocytes. Astrocytoma cell lines, U251, U373 and VM, or murine primary astrocytes were used for in vitro assay. DNA binding activities of NF-kappaB in these cells induced by interleukin (IL)-1 or LPS were inhibited by 1-BP. Consequently, the treatment of U251 cells with 1-BP resulted in suppression of NF-kappaB reporter activity. Furthermore, 1-BP blocked IkappaBalpha degradation, which is important for NF-kappaB activation. In addition, the level of Bcl-xL mRNA, which is known as an anti-apoptotic gene, were reduced in U251 treated with 1-BP or in the brain from rat exposed to 1-BP (400 ppm, 12 weeks). These results suggest that subchronic inhalation exposure to 1-BP vapor may affect the Bcl-xL expression in astrocytes.

Apyrase and 5'-nucleotidase activities in synaptosomes from the cerebral cortex of rats experimentally demyelinated with ethidium bromide and treated with interferon-beta

Apyrase and 5'-nucleotidase activities were analyzed in an ethidium bromide (EB) demyelinating model associated with interferon-beta (IFN-beta). The animals were divided in groups: I, control (saline); II, saline and IFN-beta; III, EB and IV, EB and IFN-beta. After 7, 15 and 30 days the animals (n = 5) were sacrificed and the cerebral cortex was removed for synaptosome preparation and enzymatic assays. Apyrase activity using ATP as substrate increased in groups II, III and IV (P < 0.001) after 7 days and in groups III and IV (P < 0.001) after 15 days. Using ADP as substrate, an activation of this enzyme was observed in group III (P < 0.05) after seven and 15 days. The 5'-nucleotidase activity increased in group III (P < 0.05) after 7 days and in groups II, III and IV (P < 0.001) after 15 days. After 30 days treatment, no significant alteration was observed in enzyme activities. Results showed that apyrase and 5'-nucleotidase activities are altered in demyelination events and that IFN-beta was able to regulate the adenine nucleotide hydrolysis.