The interferons: biological effects, mechanisms of action, and use in multiple sclerosis

Recombinant Interferon-β in the Treatment of Polycythemia Vera and Related Neoplasms: Rationales and Perspectives

About 30 years ago, the first clinical trials of the safety and efficacy of recombinant interferon-α2 (rIFN-α2) were performed. Since then, several single-arm studies have shown rIFN-α2 to be a highly potent anticancer agent against several cancer types. Unfortunately, however, a high toxicity profile in early studies with rIFN-α2 -among other reasons likely due to the high dosages being used-disqualified rIFN-α2, which was accordingly replaced with competitive drugs that might at first glance look more attractive to clinicians. Later, pegylated IFN-α2a (Pegasys) and pegylated IFN-α2b (PegIntron) were introduced, which have since been reported to be better tolerated due to reduced toxicity. Today, treatment with rIFN-α2 is virtually outdated in non-hematological cancers, where other immunotherapies-e.g., immune-checkpoint inhibitors-are routinely used in several cancer types and are being intensively investigated in others, either as monotherapy or in combination with immunomodulatory agents, although only rarely in combination with rIFN-α2. Within the hematological malignancies, rIFN-α2 has been used off-label for decades in patients with Philadelphia-negative chronic myeloproliferative neoplasms (MPNs)-i.e., essential thrombocythemia, polycythemia vera, and myelofibrosis-and in recent years rIFN-α2 has been revived with the marketing of ropeginterferon-α2b (Besremi) for the treatment of polycythemia vera patients. Additionally, rIFN-α2 has been revived for the treatment of chronic myelogenous leukemia in combination with tyrosine kinase inhibitors. Another rIFN formulation-recombinant interferon-β (rIFN-β)-has been used for decades in the treatment of multiple sclerosis but has never been studied as a potential agent to be used in patients with MPNs, although several studies and reviews have repeatedly described rIFN-β as an effective anticancer agent as well. In this paper, we describe the rationales and perspectives for launching studies on the safety and efficacy of rIFN-β in patients with MPNs.

Type I and II interferons toward ideal vaccine and immunotherapy

Introduction: Innate immunity is armed with interferons (IFNs) that link innate immunity to adaptive immunity to generate long-term and protective immune responses against invading pathogens and tumors. However, regulation of IFN production is crucial because chronic IFN responses can have deleterious effects on both antitumor and antimicrobial immunity in addition to provoking autoinflammatory or autoimmune conditions.Areas covered: Here, we focus on the accumulated evidence on antimicrobial and antitumor activities of type I and II IFNs. We first summarize the intracellular and intercellular mechanisms regulating IFN production and signaling. Then, we discuss the mechanisms modulating the dual nature of IFNs for both antitumor and antimicrobial immune responses. Finally, we review the detrimental role of IFNs for induction of autoinflammation and autoimmunity.Expert opinion: The current evidence suggests that the dual role of IFNs for antimicrobial and antitumor immunity is dependent not only on the timing, administration route, and dose of IFNs but also on the type of pathogen/tumor. Therefore, we think that combinatorial therapies involving IFN-inducing adjuvants and immune-checkpoint blockers may offer therapeutic potential, especially for cancer, whereas infectious, autoinflammatory or autoimmune diseases require fine adjustment of timing, dose, and route of the administration for candidate IFN-based vaccines or immunotherapies.

Gauging the role and impact of drug interactions and repurposing in neurodegenerative disorders

Neurodegenerative diseases (ND) are of vast origin which are characterized by gradual progressive loss of neurons in the brain region. ND can be classified according to the clinical symptoms present (e.g. Cognitive decline, hyperkinetic, and hypokinetic movements disorder) or by the pathological protein deposited (e.g., Amyloid, tau, Alpha-synuclein, TDP-43). Alzheimer's disease preceded by Parkinson's is the most prevalent form of ND world-wide. Multiple factors like aging, genetic mutations, environmental factors, gut microbiota, blood-brain barrier microvascular complication, etc. may increase the predisposition towards ND. Genetic mutation is a major contributor in increasing the susceptibility towards ND, the concept of one disease-one gene is obsolete and now multiple genes are considered to be involved in causing one particular disease. Also, the involvement of multiple pathological mechanisms like oxidative stress, neuroinflammation, mitochondrial dysfunction, etc. contributes to the complexity and makes them difficult to be treated by traditional mono-targeted ligands. In this aspect, the Poly-pharmacological drug approach which targets multiple pathological pathways at the same time provides the best way to treat such complex networked CNS diseases. In this review, we have provided an overview of ND and their pathological origin, along with a brief description of various genes associated with multiple diseases like Alzheimer's, Parkinson's, Multiple sclerosis (MS), Amyotrophic Lateral Sclerosis (ALS), Huntington's and a comprehensive detail about the Poly-pharmacology approach (MTDLs and Fixed-dose combinations) along with their merits over the traditional single-targeted drug is provided. This review also provides insights into current repurposing strategies along with its regulatory considerations.

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.

An update on multiple sclerosis in children: diagnosis, therapies, and prospects for the future

INTRODUCTION

Multiple sclerosis (MS), a chronic demyelinating disease of the central nervous system, is increasingly being recognized in children and adolescents. Pediatric MS follows a relapsing-remitting course at onset, with a risk for early cognitive impairment. Areas covered: In this review, we discuss the clinical features of acute demyelinating syndromes in children and risk factors that increase the likelihood of a diagnosis of MS. We also address the application of diagnostic criteria for MS in children, immunological features, therapeutic options and psychosocial considerations for children and adolescents with MS. Expert commentary: Collaborative multicenter clinical trials and research efforts are key to the advancement in understanding the pathophysiology and therapeutic strategies for multiple sclerosis across the lifespan.

High Serum Lipopolysaccharide-Binding Protein Level in Chronic Hepatitis C Viral Infection Is Reduced by Anti-Viral Treatments

Background

Lipopolysaccharide-binding protein (LBP) has been reported to associate with metabolic diseases, such as obesity, diabetes, and non-alcoholic fatty liver disease. Since chronic hepatitis C virus (HCV) infection is associated with metabolic derangements, the relationship between LBP and HCV deserves additional studies. This study aimed to determine the serum LBP level in subjects with or without HCV infection and investigate the change of its level after anti-viral treatments with or without interferon.

Methods and Findings

We recruited 120 non-HCV subjects, 42 and 17 HCV-infected subjects respectively treated with peginterferon α-2a/ribavirin and direct-acting antiviral drugs. Basic information, clinical data, serum LBP level and abdominal ultrasonography were collected. All the subjects provided written informed consent before being enrolled approved by the Research Ethics Committee of the National Taiwan University Hospital. Serum LBP level was significantly higher in HCV-infected subjects than non-HCV subjects (31.0 ± 8.8 versus 20.0 ± 6.4 μg/mL; p-value < 0.001). After multivariate analyses, LBP at baseline was independently associated with body mass index, hemoglobin A1c, alanine aminotransferase (ALT) and HCV infection. Moreover, the baseline LBP was only significantly positively associated with ALT and inversely with fatty liver in HCV-infected subjects. The LBP level significantly decreased at sustained virologic response (27.4 ± 6.6 versus 34.6 ± 7.3 μg/mL, p-value < 0.001; 15.9 ± 4.4 versus 22.2 ± 5.7 μg/mL, p-value = 0.001), regardless of interferon-based or -free therapy.

Conclusions

LBP, an endotoxemia associated protein might be used as an inflammatory biomarker of both infectious and non-infectious origins in HCV-infected subjects.

Review: The role of the liver in the response to LPS: experimental and clinical findings

The liver plays an important physiological role in lipopolysaccharide (LPS) detoxification and, in particular, hepatocytes are involved in the clearance of endotoxin of intestinal derivation. In experimental shock models, tumor necrosis factor (TNF)-α induces hepatocyte apoptosis and lethal effects are due to secreted TNF-α and not to cell-associated TNF-α. An exaggerated production of TNF-α has been reported in murine viral infections, in which mice become sensitized to low amounts of LPS and both interferon (IFN)-γ and IFN-α/β are involved in the macrophage-induced release of TNF-α. The prominent role of LPS and TNF-α in liver injury is also supported by studies of ethanol-induced hepatic damage. In humans, evidence of LPS-induced hepatic injury has been reported in cirrhosis, autoimmune hepatitis, and primary biliary cirrhosis and a decreased phagocytic activity of the reticulo-endothelial system has been found in these diseases. The origin of endotoxemia in hepatitis C virus (HCV) infected patients seems to be multifactorial and LPS may be of exogenous or endogenous derivation. In endotoxemic HCV-positive patients responsive to a combined treatment with IFN-α/ribavirin (RIB), endotoxemia was no longer detected at the end of the therapeutic regimen. By contrast, 48% of the non-responders to this treatment were still endotoxemic and their monocytes displayed higher intracellular TNF-α and interleukin (IL)-1β levels than responders. Moreover, in responders, an equilibrium between IFN-γ and IL-10 serum levels was attained. In the non-responders, serum levels of IL-10 did not increase following treatment. This may imply that an imbalance between T helper (Th)1 and Th2 derived cytokines could be envisaged in the non-responders.

Multiple Sclerosis: New Approaches to Immunotherapy

Until recently, the treatment of multiple sclerosis (MS) was restricted to symptomatic therapies. Advances in our understanding of the pathogenesis of MS are now resulting in the rapid proliferation of treatment strategies to slow or stop the progression of this disease. Clearly, immunological therapies can improve outcomes in MS and offer hope that this crippling disease can be controlled before patients develop major neurological disabilities. Immunological therapies under investigation for the treatment of MS are taking advantage of dramatic improvements in our understanding of immunoregulation. In addition, immunological treatment of MS is becoming selective relative to myelin antigens, enhancing efficacy and reducing toxicity. The Neuroscientist 2:127-136, 1996

An update on immunopathogenesis, diagnosis, and treatment of multiple sclerosis

BACKGROUND

Multiple sclerosis is an acquired demyelinating disease of the central nervous system. It is the second most common cause of disability in adults in United States after head trauma.

DISCUSSION

The etiology of MS is probably multifactorial, related to genetic, environmental, and several other factors. The pathogenesis is not fully understood but is believed to involve T-cell-mediated inflammation directed against myelin and other related proteins with a possible role for B cells. The McDonald criteria have been proposed and revised over the years to guide the diagnosis of MS and are based on clinical presentation and magnetic resonance imaging (MRI) of the brain and spinal cord to establish dissemination in time and space. The treatment of MS includes disease modification with immunomodulator drugs and symptom management to address the specific symptoms such as fatigue, spasticity, and pain.

CONCLUSION

An update on etiology, pathogenesis, diagnosis, and immunomodulatory treatment of MS is presented.

Therapeutic alpha-interferons protein: structure, production, and biosimilar

In 2007, the world solemnized the golden jubilee of the discovery of interferon (IFN). Interferon is a small protein messenger called a pluripotent cytokine, produced by several cells of the host in response to various biological as well as synthetic stimuli. There are three major classes of interferons in humans: IFN-alpha, IFN-beta, and IFN-gamma. As a treatment option, interferon-alpha (IFN-α) is the most effective one. IFN-α has proved to be effective as an antiviral therapy and tumor-fighting drug in the past two decades. Meanwhile, great progress has been achieved in establishing IFN-α as the first choice of antiviral therapy for chronic hepatitis C virus (HCV) patients. Recently, novel pegylated IFN-α2 products with extended in vivo half-lives and consensus interferon, an artificially engineered type I interferon, have been developed to substantially improve treatment regimes for HCV patients. Undesirable acute and chronic side effects in addition to immunogenicity of therapeutic IFN products remain constraints to conquer for further improvements in clinical applications of IFN. It is certainly expected that more research will be conducted in the future, not only to face these challenges but also to extend the range of IFN products and their clinical targets. The objective herein is to review the current therapeutic alpha-interferons production, formulation technologies, and prospective future for the original entity and its biogeneric version.

Psychometric properties of the Hamilton Depression Rating Scale in multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is frequently associated with depressive symptoms and major depression.

OBJECTIVE

We assessed psychometric properties of the Hamilton Depression Rating Scale (HDRS, 17-item version) for assessing depressive symptomatology in a sample of MS patients.

METHODS

Seventy patients (aged 43.3 ± 10.3 years) completed the HDRS and a thorough clinical and neuropsychological assessment, including diagnosis of major depression according to the established clinical criteria.

RESULTS

HDRS was easy to administer and acceptable, and showed fair internal consistency (Cronbach's alpha = 0.8). The HDRS showed good convergent validity with respect to neuropsychiatric inventory (NPI) subdomain of depression (r rho = .85) and good divergent validity with respect to remaining NPI subdomains (r rho < .30). Moreover, HDRS's total score correlated moderately with functional disability and apathetic symptomatology, and poorly with general cognitive status. Receiver operating characteristics curve analysis demonstrated that a cutoff >14.5 can identify clinically relevant depressive symptoms with good sensitivity (93 %) and specificity (97 %) with respect to the diagnosis of major depression. Such a cutoff identified clinically relevant depressive symptoms in 42 % of our MS sample, whereas 44.2 % patients met established clinical criteria for major depression.

CONCLUSION

The HDRS can be considered as an easy, reliable, and valid tool to assess depressive symptomatology for clinical and research purposes in non-demented MS patients.

Therapeutic strategies in multiple sclerosis: a focus on neuroprotection and repair and relevance to schizophrenia

Multiple sclerosis is the leading nontraumatic cause of neurologic disability in young adults. The need to prevent neurodegeneration and promote repair in multiple sclerosis (MS) has gained increasing interest in the last decade leading to the search and development of pharmacological agents and non-pharmacologic strategies able to target not only the inflammatory but also the neurodegenerative component of the disease. This paper will provide an overview of the therapeutics currently employed in MS, with a focus on their potential neuroprotective effects and on the MRI methods employed to detect and monitor in-vivo neuroprotection and repair and the relevance of this information to schizophrenia investigation and treatment.

Multifocal motor neuropathy: current therapies and novel strategies

Multifocal motor neuropathy (MMN) is a purely motor mononeuritis multiplex characterized by the presence of conduction block on motor but not on sensory nerves and by the presence of high titers of anti-GM1 antibodies. Several data point to a pathogenetic role of the immune system in this neuropathy, although this has not yet been proved. Several uncontrolled studies and randomized controlled trials have demonstrated the efficacy of therapy with high-dose intravenous immunoglobulin (IVIg) in MMN. However, this therapy has a short-lasting effect that needs to be maintained with periodic infusions. This can be partly overcome by the use of subcutaneous immunoglobulin (SCIg) at the same dose. The high cost and need for repeated infusions have led to the search for other immune therapies, the efficacy of which have not yet been confirmed in randomized trials. In addition, some therapies, including corticosteroids and plasma exchange, are not only ineffective but have been associated with clinical worsening. More recently, a number of novel therapies have been investigated in MMN, including interferon-β1a, the anti-CD20 monoclonal antibody rituximab and the complement inhibitor eculizumab. Preliminary data from open-label uncontrolled studies show that some patients improve after these therapies; however, randomized controlled trials are needed to confirm efficacy. Until then, IVIg (and SCIg) remains the mainstay of treatment in MMN, and the use of other immune therapies should only be considered for patients not responding to, or becoming resistant to, IVIg.

Treatment of multifocal motor neuropathy

OPINION STATEMENT

Multifocal motor neuropathy (MMN) is a treatable immune disorder of the peripheral nerves that is characterized clinically by slowly progressive or stepwise asymmetric distal > proximal, upper > lower limb weakness in multiple motor nerve distributions; electrophysiologically by multifocal motor demyelination, specifically partial motor conduction block; laboratory evidence of high serum anti-GM1 IgM antibodies; and remarkable treatment response to intravenous immunoglobulin (IVIG). IVIG has become the treatment of choice, and the U.S. Food and Drug Administration (FDA) has approved Gammagard Liquid 10 % [immune globulin infusion (human)] as a treatment for multifocal motor neuropathy (MMN). Response to IVIG in MMN is dose- and frequency-dependent, most patients needing high (2 g/kg) and frequent (every 4-8 weeks) doses for several years. Over time, response to IVIG may decrease despite higher and more frequent dosing of IVIG treatment. Subcutaneous immunoglobulin (dose equivalent to IVIG) given in weekly fashion has recently been used with equal efficacy and fewer side effects. There are some case reports and non-randomized trials suggesting variable results from therapeutic or adjunctive use of other immunosuppressive or immunomodulatory agents such as cyclophosphamide, cyclosporine, methotrexate, azathioprine, interferon beta-1a, and rituximab. Of these, cyclophosphamide and rituximab are the only immune treatments that have shown some benefits in case reports. One randomized controlled trial of mycophenolate mofetil used as adjunctive agent did not prove efficacious in altering the disease course. Although MMN, like chronic inflammatory demyelinating polyneuropathy (CIDP), is a chronic immune-mediated demyelinating neuropathy, the use of corticosteroids and plasma exchange - two other therapies used in CIDP - is not beneficial for MMN. Further investigations are warranted to evaluate the immunopathogenesis of MMN and to explore options for dose, frequency, and duration of IVIG treatment as well as the use of alternative immunomodulatory agents either as primary therapeutic or adjunctive agents.

Multiple sclerosis in children

The onset of multiple sclerosis (MS) in childhood and adolescence is being increasingly recognized. Relative to MS in adults, little is known about the diagnostic evaluation, clinical course, outcome, and management of MS in children. To remedy some of these deficiencies, pediatric MS clinics have been created in several countries to provide specialized care to, and to study, affected children. Research is currently underway to investigate the pathobiologic features of childhood-onset MS, to study the mechanisms of myelin inflammation and repair, to evaluate patient outcomes collaboratively between the different clinics, and to increase knowledge of pediatric MS for children living with the disease. It is hoped that, through an understanding of the earliest aspects of the MS disease process, critical insights will be gained about the genesis of MS.

Optimizing therapeutics in the management of patients with multiple sclerosis: a review of drug efficacy, dosing, and mechanisms of action

Multiple sclerosis (MS) is a debilitating neurological disorder that affects nearly 2 million adults, mostly in the prime of their youth. An environmental trigger, such as a viral infection, is hypothesized to initiate the abnormal behavior of host immune cells: to attack and damage the myelin sheath surrounding the neurons of the central nervous system. While several other pathways and disease triggers are still being investigated, it is nonetheless clear that MS is a heterogeneous disease with multifactorial etiologies that works independently or synergistically to initiate the aberrant immune responses to myelin. Although there are still no definitive markers to diagnose the disease or to cure the disease per se, research on management of MS has improved many fold over the past decade. New disease-modifying therapeutics are poised to decrease immune inflammatory responses and consequently decelerate the progression of MS disease activity, reduce the exacerbations of MS symptoms, and stabilize the physical and mental status of individuals. In this review, we describe the mechanism of action, optimal dosing, drug administration, safety, and efficacy of the disease-modifying therapeutics that are currently approved for MS therapy. We also briefly touch upon the new drugs currently under investigation, and discuss the future of MS therapeutics.

A review of the use of biological agents for chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a group of idiopathic, acquired, immune-mediated inflammatory demyelinating diseases of the peripheral nervous system. A majority of patients with CIDP respond to "first-line" treatment with IVIG, plasmapheresis and/or corticosteroids. There exists insufficient evidence to ascertain the benefit of treatment with "conventional" immunosuppressive drugs. The inconsistent efficacy, long-term financial burden and health risks of non-specific immune altering therapy have drawn recurrent attention to the possible usefulness of a variety of biological agents that target key aspects in the CIDP immunopathogenic pathways. This review aims to give an updated account of the scientific rationale and potential use of biological therapeutics in patients with CIDP. No specific treatment recommendations are given. The discovery, development and application of biological markers by modern molecular diagnostic techniques may help identify drug-naïve or treatment-resistant CIDP patients most likely to respond to targeted immunotherapy.

Neutralizing antibodies to interferon beta-1b multiple sclerosis: a clinico-radiographic paradox in the BEYOND trial

BACKGROUND

The frequency and impact of neutralizing antibodies (NAbs) to interferon beta-1b (IFNβ-1b) on clinical and radiographic outcomes is controversial.

OBJECTIVE

To assess NAb impact in the BEYOND study.

METHODS

2244 patients were randomized (2:2:1) to receive IFNβ-1b, either 250 or 500 µg, or glatiramer acetate, 20 mg, and observed for 2-3.5 years. NAb titers were determined every 6 months. A titer ≥20 NU/ml was considered NAb positive. Efficacy was compared between NAb-positive and NAb-negative patients, using comprehensive statistical analyses, taking into account the delayed appearance of NAbs, the time-dependent changes in the relapse rate, spontaneous reversions to NAb-negative status, NAb-titer level, and also adjusting for baseline factors.

RESULTS

In the IFNβ-1b 250 µg group, NAb-positive titers were detected (≥ once) in 319 patients (37.0%); of these, 112 (35.1%) reverted to NAb-negative status. In the IFNβ-1b 500 µg group, 340 patients (40.7%) became NAb-positive and 119 (35.0%) reverted to NAb-negative status. In both IFNβ groups, especially the 250 µg arm, NAb-positive status was not associated with a convincing impact on any clinical outcome measure by any statistical analysis. By contrast, in both IFNβ groups, NAbs were associated with a very consistent deleterious impact on most MRI outcomes.

CONCLUSION

There was a notable dissociation between the impact of NAbs on MRI and clinical outcomes. On MRI measures, the impact was consistent and convincing, whereas on clinical measures a negative impact of NAbs was not found. The basis for this clinico-radiographic paradox is unknown but it suggests that the relationship between NAbs and the therapeutic effects of IFNβ-1b is complex.

Differential gene expression and translational approaches to identify biomarkers of interferon beta activity in multiple sclerosis

More than 16 years ago human interferon-&#x03B2;-1b (IFN-&#x03B2;-1&#x03B2;) was shown to be effective in the treatment of the relapsing-remitting form of multiple sclerosis (MS). Over time, IFN-&#x03B2; has been demonstrated to be both a safe and effective treatment. However, the mechanism of action of IFN-&#x03B2; in MS remains unknown. To better understand the mechanism of action of IFN-&#x03B2;, considerable effort has been made in transcriptional profiling of peripheral blood mononuclear cells collected from MS patients. IFN-&#x03B2; is known to induce a large number of genes that play an important role in regulating responses to viral infection, immune modulation, and cell proliferation. Identifying differentially induced genes that are linked to the beneficial effects observed during treatment is under active investigation. IFN biomarkers in MS patients have been proposed but have not been clearly confirmed in independent studies or consistently correlated with clinical measures of disease progression. Organizing single genes or gene signatures grouped according to molecular mechanisms meaningful in MS may help to link IFN activity measurements to clinical outcomes. In this review, IFN activity measurements will be discussed with a specific emphasis on what is known about differential gene expression and treatment effects in MS.

Biological effects of Byrsocarpus coccineus in vitro

CONTEXT

Byrsocarpus coccineus Schum. and Thonn. (Connaraceae) is a scandent shrub widely employed as a medicinal remedy for various disease conditions in West Africa.

OBJECTIVE

This study evaluated fractions of B. coccineus for modulation of cytochrome P450 (CYP) enzyme activity, cytokine production, and proliferation.

MATERIALS AND METHODS

The BROD (benzyloxyresorufin O-debenzylase) and BFCOD (benzyloxy-4-[trifluoromethyl]-coumarin O-debenzyloxylase) assays were used to evaluate effect on CYP2B1/2 and CYP3A4 enzyme activity. Effects on cytokine production and proliferation of HT29 cells were investigated using interferon expression assay and MTT (3-3[4,5-dimethyl-2-thiazolyl]-2-5-diphenyl-2H-tetrazolium bromide) assay, respectively.

RESULTS

Fractions derived from the organic solvent extraction of B. coccineus produced significant (p<0.05) stimulation of human hepatic CYP2B1/2 activity in the BROD assay. The greatest effects were elicited at 1 ng/mL corresponding to ∼ 3-fold stimulation of enzyme activity. Enhancement of CYP3A4 enzyme activity was also observed in the BFCOD assay. Other fractions from the organic extract showed significant antiproliferative effects on HT29 cells at 100 μg/mL. Fractions obtained from the aqueous extract of B. coccineus (1 µg/µL) significantly stimulated the expression of IFNα2a and IFNβ in peripheral blood mononuclear cells (PBMC), causing a maximum 26-fold increase of IFNα2a-transcript.

DISCUSSION AND CONCLUSION

The effect on CYP suggests that B. coccineus may reduce the therapeutic efficacy of co-administered drugs. This justifies the need for proper education of patients by healthcare practitioners on the outcomes of drug-herb interactions. This study identifies several in vitro activities that could underlie the attributed uses of this plant in traditional African medicine (TAM).

Beta-interferons in multiple sclerosis: a single center experience in India

Background:

Indian-Asian multiple sclerosis behaves somewhat differently from Western disease. It is not known if the response to β-interferon is also different.

Aim:

To demonstrate the decrease in relapses with β-interferon in Indian patients with multiple sclerosis.

Patients and Methods:

Patients with relapsing–remitting or secondary progressive multiple sclerosis with at least two relapses were started on β-interferon.

Results:

Sixteen patients were followed up for a period of 1–3 years. Fifteen had relapsing–remitting multiple sclerosis (MS). The mean number of relapses in these patients before interferons were started was 3.4. The mean yearly relapse rate was 1.3. The mean Kurtzke Expanded Disability Status Scale (EDSS) at the start of β-interferon therapy in relapsing–remitting MS was 1.7. Ten of these patients were on Avonex^® (interferon β1a) and six (including the patient with secondary progressive MS) were on Betaferon^® (interferon β1b). On follow-up, three patients (two on Avonex^® and one on Betaferon^® ) had relapses. The respective β-interferon being received by these patients was continued, with no further relapses. The remaining patients had no relapse or clinical or MRI progression after starting the drug. The side effect profile of the drug in these patients was favorable; although nearly all developed fever on the first day of the injection, only 50% of the patients continued to have fever after 3 months. Two patients developed psychiatric symptoms, requiring discontinuation of the drug.

Conclusion:

Our prospective follow-up study shows that β-interferons are safe and effective in Indian patients with relapsing–remitting or secondary progressive MS.

A role for interferon-beta in Guillain-Barré Syndrome?

Guillain-Barré syndrome (GBS) is an acute inflammatory demyelinating neuropathy that is associated with long-lasting morbidity and a substantial risk of mortality. The 2 reference treatments, plasma exchange and intravenous immunoglobulins (IVIg), do not change the functional prognosis for the most severely ill patients. The pathogenesis of GBS involves humoral and cellular immune dysfunctions that have only recently been characterised. Antibodies to nerve antigens may participate in complement activation, antibody-dependent macrophage cytotoxicity and reversible conduction failure. The cellular immune reaction is associated with increases in pro-inflammatory cytokines [such as tumour necrosis factor-alpha (TNFalpha)] and matrix metalloproteinases (MMPs; e.g. MMP-9), and a decrease in anti-inflammatory cytokines [such as transforming growth factor-beta1 (TGFbeta1)]. All the changes favour adhesion to and transmigration across the endothelium of immune cells, a key phenomenon associated with GBS. Recovery from GBS is characterised by the normalisation of these changes. Experimental allergic neuritis (EAN), the experimental model of GBS, has strikingly similar immunological characteristics. The usual treatment options for patients with GBS (plasma exchange and IVIg) mainly target the humoral component of the immune response. Interferon-beta (IFNbeta) is a cellular immunomodulator that inhibits antigen presentation and TNFalpha production and binding, and modulates macrophage properties. IFNbeta increases anti-inflammatory T cell functions and the production of anti-inflammatory cytokines, such as TGFbeta1. IFNbeta has important effects on leukodiapedesis, caused by modulating the expression of cell adhesion molecules and the MMP-9 proteinases. It has been used with success in EAN, in some patients with acute exacerbation of chronic inflammatory demyelinating polyneuropathy, and in 1 patient with GBS. The pathophysiology of patients with GBS, an understanding of IFNbeta properties and results of experimental studies support the investigation of IFNbeta in trials of patients with GBS.

Interferon-triggered transcriptional cascades in the oligodendroglial lineage: a comparison of induction of MHC class II antigen between oligodendroglial progenitor cells and mature oligodendrocytes

Interferon-gamma induces major histocompatibility complex class II (MHC-II) in proliferating oligodendroglial progenitor cells (OPC), but to a much lesser extent in mature oligodendrocytes. Interferon-beta has virtually no effects on MHC-II induction even in OPC. Interferon-gamma-mediated transcriptional induction of CIITA, a critical regulator of MHC-II induction, was 6-fold lower in mature oligodendrocytes than in OPC, and entirely dependent on promoter IV, suggesting that the transcriptional activity of promoter IV is down-regulated after differentiation. The distinct difference in MHC-II induction between interferon-gamma and interferon-beta is attributed to transient interferon-beta-mediated activation of STAT1-IRF1 signaling compared to the sustained interferon-gamma-mediated activation.

Interferon-induced Mx proteins in brain tissue of multiple sclerosis patients

BACKGROUND AND PURPOSE

Recombinant interferon-beta is proven as an effective long-term treatment in patients with multiple sclerosis (MS). Unlike in other chronic inflammatory diseases, endogenous synthesis of type I interferons (IFN-alpha and IFN-beta) has not been studied extensively in MS. Mx proteins A and B (MxA and MxB) are intracellular proteins that are induced exclusively by type I IFNs. We investigated the expression of Mx proteins in post-mortem brain tissue of IFN-beta-naïve MS patients as a marker for endogenous synthesis of type I IFNs.

METHODS

By employing monoclonal antibodies specific for MxA and MxB positive staining was detectable predominantly in reactive astrocytes within the MS plaques but also in endothelial and ependymal cells as well as in lymphocytic infiltrates.

RESULTS

This is of interest in view of results previously published by our group and others that Mx protein concentrations measured by ELISA increase in blood samples from MS patients after IFN-beta therapy.

CONCLUSIONS

In MS, Mx proteins are detectable in plaques suggesting endogenous synthesis of type I IFNs as part of the acute inflammatory process.

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.

Interferon-beta treatment for multiple sclerosis

Multiple sclerosis (MS) is the leading nontraumatic cause of neurologic disability in young adults. Interferon-beta, approved for use in 1993, was the first treatment to modify the course and prognosis of the disease and remains a mainstay of MS treatment. Numerous large-scale clinical trials in early, active patient populations have established the clinical efficacy of interferon-beta in reducing relapses and delaying disability progression. Although its mechanism of action remains incompletely understood, a reduction in active lesions seen on magnetic resonance imaging implies primary anti-inflammatory properties, a mechanism supported by basic immunologic research. Variation in individual patient responsiveness to interferon-beta may be due to disease variability or differential induction of interferon-stimulated genes. The magnitude of the therapeutic effect appears to be similar among products, but the optimal dose, route, and frequency of administration of the drug remain uncertain.

Mechanisms of interferon-beta-induced survival in fetal and neonatal primary astrocytes

BACKGROUND

We have previously shown that interferon-beta (IFN-beta) is a potent promoter of astrocyte survival. Although the mechanism(s) by which IFN-beta promotes astrocyte survival have not been completely elucidated, it has been shown that IFN-beta directly stimulates survival signaling pathways. In the present report, we took advantage of the differences in the susceptibility of fetal and neonatal astrocytes to apoptosis to further investigate the mechanism(s) underlying the antiapoptotic effect of IFN-beta.

METHODS

Primary monolayer cultures of cortical astrocytes were established from neonatal (3- to 6-day-old) or fetal (embryonic days: E15 or E17) Sprague-Dawley rat cerebral cortices. Apoptotic cell death was determined by fluorescent-microscopic analysis of staining patterns of cell DNA with Hoechst 33258, and determination of annexin V binding.Akt phosphorylation was detected by Western blottingusing a commercial kit that allows specific recognition of both non-phosphorylated and serine-phosphorylated Akt.

RESULTS

In the present work, we have found that primary astrocytes obtained from neonatal rats are resistant to apoptosis induced by serum starvation, though cell death may be induced by combining serum starvation with sodium butyrate treatment. This effect is counteracted by IFN-beta treatment through a mechanism that involves phosphatidylinositol 3-kinase stimulation.

CONCLUSIONS

IFN-beta can be considered as a neuroprotective agent and, therefore, part of its beneficial effects in multiple sclerosis (MS) treatment may depend on its capacity to protect astrocytes against the apoptotic cell death that occurs in the course of the MS lesions.

Drug Insight: interferon treatment in multiple sclerosis

Multiple sclerosis (MS) is a chronic demyelinating disease of the CNS. Between 1987 and 1997, clinical trials of three preparations of recombinant interferon-beta were conducted in patients with MS, ushering in a new therapeutic era. These medications have demonstrable benefits and seem to be safe; they represent an important advance in MS treatment. All three formulations of interferon-beta had modest effects on relapses and short-term progression of disability, but the effects on MRI lesion parameters were more substantial. The benefits were greater in clinically isolated syndromes and relapsing-remitting MS than in secondary progressive MS. Although these drugs have been shown to be effective, however, their long-term impact on clinically relevant disability progression is uncertain, and there are many areas of controversy in the MS field regarding the use of these products. There is still a need for more effective treatments, which might include new agents or combination therapies.

Treatment of children and adolescents with multiple sclerosis

The onset of multiple sclerosis is being increasingly recognized in children and adolescents. There are now approved immunomodulatory therapies for adults with multiple sclerosis. Treatment early in the disease course appears to have a greater impact on disease outcome, an issue of particular importance for children who face decades of multiple sclerosis disease activity. This review summarizes the multiple sclerosis therapies currently available, efficacy data available from studies of these medications in adults and limited information on the use of these medications in children. Future directions in multiple sclerosis therapeutics and specific issues relating to pediatric multiple sclerosis are discussed.

Primary progressive multiple sclerosis : current and future treatment options

Approximately 10% of patients with multiple sclerosis (MS) run a primary progressive course characterised by an accumulation of neurological deficits without relapse or remission. Designing therapeutic trials in primary progressive MS (PPMS) has presented several problems. Patient recruitment may be difficult because of the relative rarity of PPMS and historically has been hindered by the lack of specific diagnostic criteria. There has been a limited choice of validated outcome measures, although, in recent studies, the MS functional composite measure and magnetic resonance imaging measures of lesion load and atrophy have been widely used. Despite these problems, several trials have been designed specifically for PPMS, including exploratory randomised controlled trials of interferon-beta-1a and interferon-beta-1b and mitoxantrone, a phase III trial of glatiramer acetate, and an open-label study of riluzole. Patients with PPMS have also been included in randomised controlled trials of azathioprine, methotrexate, cladribine, intravenous immunoglobulin and cyclophosphamide, and open-label studies of haematopoietic stem cell transplantation and pirfenidone in progressive MS. However, no treatment has been proven definitively to modify the course of the disease. Looking to the future, therapeutic agents should aim to target the underlying pathogenic mechanisms in PPMS. As a result of the relative lack of inflammation in PPMS, neuroprotective agents that target neuronal loss directly, rather than inflammation, may be more worthwhile. However, further investigation into the pathogenic mechanisms in PPMS is required to guide the development of future therapeutic agents.

New insights into cell responses involved in experimental autoimmune encephalomyelitis and multiple sclerosis

Animal models of autoimmune diseases such as experimental autoimmune encephalomyelitis (EAE) are inflammatory demyelinating diseases which comprise a heterogeneous group of disorders that affect the peripheral and central nervous systems. EAE presents close similarities with multiple sclerosis (MS), a chronic inflammatory disease affecting central nervous system (CNS) white matter. Many studies have shown EAE to be a particularly useful animal model for the understanding of both the mechanisms of immune-mediated CNS pathology and the progressive clinical course of multiple sclerosis. Previous data has underlined the importance of CD4+ T cell involvement in mediating the autoimmune processes associated with the destruction of myelin and the role of the T helper 1 (Th1) pattern of cytokine secretion. However, EAE studies have also demonstrated that other cells involved in innate and/or adaptive immune responses may also play a critical role in the early and progressive events of the immune reaction leading to inflammation and CNS damage. In this review, we present such new data and discuss their potent implication for future new therapeutical approaches.

Interferon-beta1a treatment for multiple sclerosis

Although multiple sclerosis is probably the most common cause of neurologic disability in young adults, the cause is unknown, the prognosis uncertain and available treatments unsatisfactory. Multiple sclerosis is an inflammatory autoimmune disorder of the CNS and the result of both environmental factors and susceptibility genes. The prognosis is difficult or impossible to predict at the time of diagnosis. Treatments that modulate the course of the disease have only recently become available but the long-term aim to prevent disability and promote repair remains distant. Interferon-beta is the most widely used therapy. The efficacy of interferon-beta in the short term is well documented in many large treatment trials, but the treatment effects are only modest and many issues relating to efficacy in the long term are unresolved. These include uncertain benefit on conversion to secondary-progressive multiple sclerosis, the relevance of neutralizing antibodies and the controversial effect on multiple sclerosis-related brain atrophy.

Proteomic and transcriptomic characterization of interferon-?-induced human primary T helper cells

Interferon-alpha (IFN-alpha) is a multifunctional cytokine that modulates immune response. In spite of the numerous comprehensive studies on the effects of IFN-alpha on various cell types, novel characteristics of this versatile agent emerge continuously. In the present study a differential proteomic approach was used to identify new IFN-alpha-regulated proteins in human primary CD4(+) T cells. Two IFN-alpha-inducible proteins, soluble N-ethylmaleimide-sensitive factor attachment protein alpha (alpha-SNAP) and cleavage stimulation factor-64 (CstF-64) previously not described in this context, were identified. Additionally, several proteins already known as IFN-stimulated genes were observed. The results of proteomics experiments were further studied at the mRNA level using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Both peripheral blood and cord blood CD4(+) T cells were used in order to see if there are differences in IFN-alpha response between these populations. Differences were observed between the IFN-alpha-induced expression kinetics in peripheral blood and cord blood transcripts. The induction was more rapid in peripheral blood than in cord blood cells. CstF-64 expression was upregulated by IFN-alpha at the protein, but not at the mRNA level.

Interferons in relapsing-remitting multiple sclerosis: are there benefits from long-term use?

Multiple sclerosis (MS) is one of the most common chronic neurological diseases in young adults in western countries. An important aspect of treatment of this disease is the use of interferons (IFNs). These are molecules with antiviral, immunomodulatory, antiproliferative and hormonal activities. IFNbeta, a class I IFN, has been used extensively in the therapy of MS, particularly in its relapsing-remitting (RRMS) phase, the most frequent clinical form of the disease. Although the available evidence from published clinical trials is difficult to evaluate because of methodological differences, an unbiased review of the data reveals sufficient evidence to conclude that treatment with IFNbeta in RRMS is both efficacious and safe, at least over the periods so far investigated (up to 4-6 years). While there is no reason to suspect that IFNbeta should not continue to be efficacious and safe over the longer term, studies investigating these questions over longer periods and including greater numbers of patients are needed.

Combination therapy for multiple sclerosis: the treatment strategy of the future?

Multiple sclerosis (MS) is an inflammatory autoimmune disease characterised by demyelination and axonal loss in the CNS. Although new immunomodulatory therapies including interferon-beta and glatiramer acetate became available during the last decade, these therapies are only partially effective. There is a continuing need to develop more effective treatment strategies to combat the chronic and progressive aspects of the disease. In view of the complex pathophysiology underlying the MS disease process, combination therapy offers a rational therapeutic approach. Combining immunomodulatory agents with different mechanisms of action that promote synergistic or additive effects represents an important objective in MS therapeutic research. Ultimately, the optimal therapies will likely include strategies that promote repair and limit tissue destruction in combination with anti-inflammatory interventions.

Biological activity of interferon betas in patients with multiple sclerosis is affected by treatment regimen and neutralising antibodies

BACKGROUND

MxA gene expression is one of the most appropriate markers of biological activity of exogenous interferon (IFN) beta.

METHODS

We quantified MxA mRNA for five consecutive days in 62 patients treated with IFN beta (16, Avonex; 10, Betaferon; 24, Rebif 22; 12, Rebif 44), by quantitative-competitive polymerase chain reaction. Every three months, IFN beta induced neutralising antibodies (NAbs) were evaluated in sera using a cytopathic effect assay.

RESULTS

Two categories of patients were identified: one group (49/62) had a sharp post-injection increase in MxA expression (defined as "IFN beta biological responder"), whereas the other group (13/62) had no MxA induction after IFN beta administrations (defined as "IFN beta biological non-responder"). In 11/13 biological non-responders, the persistent presence of NAbs correlated with abolished biological activity, independently of treatment regimen. The two remaining IFN beta biological non-responders were NAb-. Among the 49 IFN beta biological responders, biological activity was comparable between the four preparations on day 2 and 3 (+12 and +36 hours post-injection), but it was greater in Betaferon and both Rebif preparations on day 1, 4, and 5. In biological responders treated three times a week, only 82% (59/72) of injections were considered effective, compared with 100% (13/13) of Avonex injections.

CONCLUSION

Our results suggest that an optimal IFN beta regimen is not yet available: Avonex, given once a week, shows lower cumulative biological activity. On the other hand, both Betaferon and Rebif, given three times a week, show 18% biologically ineffective injections and higher risk of developing NAbs, which abolish biological activity.

B cells in multiple sclerosis

The most common laboratory abnormality in multiple sclerosis (MS) is an increased amount of cerebrospinal fluid IgG and the presence of oligoclonal bands. Despite studies of the humoral response that suggest the involvement of an infectious agent or autoantigen in disease, the major targets of the oligoclonal response are still unknown. Identification of these targets will reveal valuable insights into the cause and pathogenesis of MS and is likely to lead to effective treatment.

Multiple sclerosis and depression: influence of interferon beta therapy

BACKGROUND AND OBJECTIVES

Depression is frequently part of the clinical picture of multiple sclerosis (MS). Major depression affects one in two patients with MS during the course of their lifetime. Our objectives were to determine first, whether interferon beta-1a (IFNbeta-1a) treatment increases the risk or level of depression and, secondly, whether depression status and depression evolution are related to the clinical characteristics of the disease.

PATIENTS AND METHODS

We investigated 106 consecutive patients with relapsing remitting MS treated with IFNbeta-1a (Avonex). Patients with evidence of severe depression were excluded. The depression status, scored on the Beck Depression Inventory (BDI-II) (stratified as minimum, mild, moderate or severe level), and disability, scored on the Expanded Disability Status Scale (EDSS), were evaluated before and after 12 months of IFNbeta-1a treatment.

RESULTS

At baseline, 85% of patients had a minimum or a mild depression status and after 12 months of treatment most of them (83%) retained their baseline status. Beck scores before and after treatment were not significantly different (P = 0.63). There was no correlation between age, gender, duration of illness or EDSS score and Beck score at baseline (P = 0.696). Patients with disability progression after one year of IFNbeta-1a treatment had a significantly higher Beck score at baseline than patients without disability progression (P = 0.003).

CONCLUSION

IFNbeta-1a (Avonex) does not seem to significantly influence the depression status of MS patients even in those with disability progression.

Persistent neutralizing antibodies abolish the interferon beta bioavailability in MS patients

BACKGROUND

MxA is an antiviral protein exclusively induced by type I interferons (IFN) and some viruses, and MxA gene expression is one of the most appropriate markers for measuring the biologic activity of exogenous IFNbeta.

METHODS

A new quantitative-competitive PCR method was used to quantify MxA mRNA in peripheral blood mononuclear cells of 99 treatment-naïve and 92 IFNbeta-treated patients with MS (22 Avonex, 17 Betaferon, and 53 Rebif-22). Every 3 months, IFNbeta-induced neutralizing antibodies (NAb) were evaluated in sera using a cytopathic effect assay. Three categories of patients were identified: NAb negative (NAb-), persistent NAb positive (NAb+, >or=2 consecutive positive samples), and isolated NAb+ (one positive sample).

RESULTS

Treatment-naïve patients expressed detectable MxA mRNA levels (mean = 36 +/- 32 fg MxA/pg glyceraldehyde-3-phosphate dehydrogenase (GAPDH); range 1 to 160) and an upper normal threshold was established (mean + 3 SD = 132 fg MxA/pg GAPDH). IFNbeta-treated patients exhibited more than 11-fold higher levels (mean = 412 +/- 282 fg MxA/pg GAPDH; range 16 to 1,172). However, 17 patients did not exhibit an increase in MxA mRNA level; 15 of these 17 patients showed a concurrent Nab+ titer. Moreover, 13 were persistent NAb+. Isolated NAb+ patients did not show a decrease in bioavailability of IFNbeta (n = 9; mean = 567 +/- 366 fg MxA/pg GAPDH; range 83 to 1,120). In NAb- patients, bioavailability was comparable among the three different IFNbeta preparations 12 hours after injection.

CONCLUSION

During IFNbeta therapy, the presence of NAb reduced or abolished bioavailability in a relevant percentage of patients. These data could be important for the early detection of patients with MS who are not responsive to IFNbeta therapy.

Nitric oxide-induced mitochondrial dysfunction: implications for neurodegeneration

Excessive generation of nitric oxide (NO) has been implicated in the pathogenesis of several neurodegenerative disorders. Damage to the mitochondrial electron transport chain has also been implicated in these disorders. NO and its toxic metabolite peroxynitrite (ONOO(-)) can inhibit the mitochondrial respiratory chain, leading to energy failure and ultimately cell death. There appears to be a differential susceptibility of brain cell types to NO/ONOO(-), which may be influenced by factors including cellular antioxidant status and the ability to maintain energy requirements in the face of marked respiratory chain damage. Although formation of NO/ONOO(-) following cytokine exposure does not affect astrocyte survival, these molecules may diffuse out and cause mitochondrial damage to neighboring NO/ONOO(-)-sensitive cells such as neurons. Evidence suggests that NO/ONOO(-) causes release of neuronal glutamate, leading to glutamate-induced activation of neuronal NO synthase and generation of further damaging species. While neurons appear able to recover from short-term exposure to NO/ONOO(-), extending the period of exposure results in persistent damage to the respiratory chain and cell death ensues. These findings have important implications for acute infection vs. chronic neuroinflammatory disease states. The evidence for NO/ONOO(-)-mediated mitochondrial damage in neurodegenerative disorders is reviewed and potential therapeutic strategies are discussed.

A comparison of the mechanisms of action of interferon beta and glatiramer acetate in the treatment of multiple sclerosis

BACKGROUND

The development of immunomodulatory agents has represented a major advance in the treatment of multiple sclerosis (MS). To date, immunomodulatory agents approved for the treatment of relapsing MS in the United States include 3 forms of recombinant interferon (IFN) beta (2 formulations of IFN beta-1a and 1 of IFN beta-1b) and synthetic glatiramer acetate (GA). Recognition of how these agents work to regulate the immune system may lead to a better understanding of disease mechanisms, as well as to development of more effective therapies or combinations of therapy.

OBJECTIVE

This article reviews the potential mechanisms of action of IFN beta products and GA in the context of their regulatory effects on autoimmune components that may be of importance in MS.

METHODS

MEDLINE and Current Contents/Clinical Medicine were searched for articles published in English from 1993 to the present using the search terms interferon beta, glatiramer acetate, and multiple sclerosis.

RESULTS

IFN beta products affect the disease process in MS through multiple potential mechanisms of action, including antiviral, antiproliferative, and anti-inflammatory effects. The mechanisms of action of GA are less clear, but may involve immune regulation induced by a gradual shift of T-cell phenotype from proinflammatory (type 1 T-helper cells) to anti-inflammatory (type 2 T-helper cells) and interference with antigen presentation.

CONCLUSION

Understanding the mechanisms of action of IFN beta products and GA provides important insights into the disease processes involved in MS.

Ingested type I interferon: a potential treatment for autoimmunity

We have proposed a unifying hypothesis of the etiopathogenesis of autoimmunity that defines autoimmunity as a type I interferon (IFN) immunodeficiency syndrome. We have examined toxicity and potential efficacy in three phase I (type 1 diabetes, rheumatoid arthritis, multiple sclerosis) and one phase II clinical trials in multiple sclerosis (MS). In a phase I open-label trial in type 1 diabetes, ingested IFN-alpha preserved residual beta cell function in recent onset patients. In a second phase I trial, treatment of rheumatoid arthritis (RA) with ingested IFN-alpha reduced the secretion of interleukin-1 (IL-1), a proinflammatory cytokine. In a third phase I trial in MS, there was a significant decrease in peripheral blood mononuclear cell (PBMC) IL-2 and IFN-gamma production after ingesting IFN-alpha. In a phase II randomized, placebo-controlled, double-blind trial in MS, 10,000 IU ingested IFN-alpha significantly decreased gadolinium enhancements compared with the placebo group at month 5. Tumor necrosis factor-alpha (TNF-alpha) and IFN-gamma cytokine secretion in the 10,000 IU group at month 5 showed a significant decrease that corresponded with the effect of ingested IFN-alpha on decreasing gadolinium enhancements. Ingested IFN-alpha was not toxic in any of these clinical trials. These studies suggest that ingested IFN-alpha may have a potential role in the treatment of autoimmunity.

Modulation of astrocyte inducible nitric oxide synthase and cytokine expression by interferon beta is associated with induction and inhibition of interferon gamma-activated sequence binding activity

Although interferon (IFN)-beta is firmly established as a therapeutic agent for multiple sclerosis, information regarding its role in astrocyte cytokine production is limited. In primary cultures of human astrocytes, we determined the effects of IFN-beta on astrocyte cytokine [tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6] and inducible nitric oxide synthase (iNOS) expression by ribonuclease protection assay and ELISA. We found that IFN-beta inhibited astrocyte cytokine/iNOS induced by IL-1 plus IFN-gamma, but in the absence of IFN-gamma, IFN-beta enhanced IL-1-induced cytokine/iNOS expression. Electrophoretic mobility shift analysis (EMSA) demonstrated that IFN-gamma induced sustained IFN-gamma-activated sequence (GAS) binding, while IFN-beta induced transient GAS binding. When used together, IFN-beta inhibited IFN-gamma-induced GAS binding activity. Nuclear factor-kappa B (NF-kappaB) activation was not altered by either IFNs, whereas IFN stimulated response element (ISRE) was only activated by IFN-beta and not IFN-gamma. These results suggest that IFN-beta can both mimic and antagonize the effect of IFN-gamma by modulating induction of nuclear GAS binding activity. Our results demonstrating differential regulation of astrocyte cytokine/iNOS induction by IFN-beta are novel and have implications for inflammatory diseases of the human CNS.

Myelin basic protein-primed T cells induce nitric oxide synthase in microglial cells. Implications for multiple sclerosis

The presence of autoreactive T cells recognizing self myelin antigens is necessary for the development of central nervous system autoimmune diseases such as multiple sclerosis (MS). The present study was undertaken to investigate the role of myelin basic protein (MBP)-primed T cells in the expression of inducible nitric oxide synthase (iNOS) in microglial cells. MBP-primed T cells alone markedly induced the production of NO and the expression of iNOS protein and mRNA in mouse BV-2 microglial cells. Similarly, MBP-primed T cells also induced the production of NO in mouse primary microglia. This induction of NO production was primarily dependent on the contact between MBP-primed T cells and microglia. The expression of very late antigen-4 (VLA-4) on the surface of MBP-primed T cells and inhibition of MBP-primed T cell-induced microglial NO production by functional blocking of antibodies to the alpha(4) chain of VLA-4 (CD49d) suggest that VLA-4 integrin on MBP-primed T cells plays an important role in contact-mediated induction of iNOS. Since IFN-beta has been used to treat MS patients, we examined the effect of IFN-beta on MBP-primed T cell-induced the production of NO. Surprisingly, IFN-beta alone induced the production of NO in microglial cells. However, the pretreatment of MBP-primed T cells with IFN-beta inhibited the expression of VLA-4 integrin on the surface of MBP-primed T cells and thereby inhibited the ability of those T cells to induce the production of NO in microglial cells. This study illustrates a novel role of neuroantigen-primed T cells in inducing contact-mediated expression of iNOS in microglial cells that may participate in the pathogenesis of MS.