Analysis of Gene Expression in MOG-Induced Experimental Autoimmune Encephalomyelitis After Treatment With a Novel Brain-Penetrating Antioxidant

Emerging therapeutic opportunities of novel thiol-amides, NAC-amide (AD4/NACA) and thioredoxin mimetics (TXM-Peptides) for neurodegenerative-related disorders

Understanding neurodegenerative diseases have challenged scientists for decades. It has become apparent that a decrease in life span is often correlated with the development of neurodegenerative disorders. Oxidative stress and the subsequent inflammatory damages appear to contribute to the different molecular and biochemical mechanisms associated with neurodegeneration. In this review, I examine the protective properties of novel amino acid based compounds, comprising the AD series (AD1-AD7) in particular N-acetylcysteine amide, AD4, also called NACA, and the series of thioredoxin mimetic (TXM) peptides, TXM-CB3-TXM-CB16. Designed to cross the blood-brain-barrier (BBB) and permeate the cell membrane, these antioxidant/anti-inflammatory compounds may enable effective treatment of neurodegenerative related disorders. The review addresses the molecular mechanism of cellular protection exhibited by these new reagents, focusing on the reversal of oxidative stress, mitochondrial stress, inflammatory damages, and prevention of premature cell death. In addition, it will cover the outlook of the clinical prospects of AD4/NACA and the thioredoxin-mimetic peptides, which are currently in development.

Bioinformatics Analyses Determined the Distinct CNS and Peripheral Surrogate Biomarker Candidates Between Two Mouse Models for Progressive Multiple Sclerosis

Previously, we have established two distinct progressive multiple sclerosis (MS) models by induction of experimental autoimmune encephalomyelitis (EAE) with myelin oligodendrocyte glycoprotein (MOG) in two mouse strains. A.SW mice develop ataxia with antibody deposition, but no T cell infiltration, in the central nervous system (CNS), while SJL/J mice develop paralysis with CNS T cell infiltration. In this study, we determined biomarkers contributing to the homogeneity and heterogeneity of two models. Using the CNS and spleen microarray transcriptome and cytokine data, we conducted computational analyses. We identified up-regulation of immune-related genes, including immunoglobulins, in the CNS of both models. Pro-inflammatory cytokines, interferon (IFN)-γ and interleukin (IL)-17, were associated with the disease progression in SJL/J mice, while the expression of both cytokines was detected only at the EAE onset in A.SW mice. Principal component analysis (PCA) of CNS transcriptome data demonstrated that down-regulation of prolactin may reflect disease progression. Pattern matching analysis of spleen transcriptome with CNS PCA identified 333 splenic surrogate markers, including Stfa2l1, which reflected the changes in the CNS. Among them, we found that two genes (PER1/MIR6883 and FKBP5) and one gene (SLC16A1/MCT1) were also significantly up-regulated and down-regulated, respectively, in human MS peripheral blood, using data mining.

Modulating inflammation and neuroprotection in multiple sclerosis

Multiple sclerosis (MS) is a neurological disorder of the central nervous system with a presentation and disease course that is largely unpredictable. MS can cause loss of balance, impaired vision or speech, weakness and paralysis, fatigue, depression, and cognitive impairment. Immunomodulation is a major target given the appearance of focal demyelinating lesions in myelin-rich white matter, yet progression and an increasing appreciation for gray matter involvement, even during the earliest phases of the disease, highlights the need to afford neuroprotection and limit neurodegenerative processes that correlate with disability. This review summarizes key aspects of MS pathophysiology and histopathology with a focus on neuroimmune interactions in MS, which may facilitate neurodegeneration through both direct and indirect mechanisms. There is a focus on processes thought to influence disease progression and the role of oxidative stress and mitochondrial dysfunction in MS. The goals and efficacy of current disease-modifying therapies and those in the pipeline are discussed, highlighting recent advances in our understanding of pathways mediating disease progression to identify and translate both immunomodulatory and neuroprotective therapeutics from the bench to the clinic.

Tolerability and Safety of Combined Glatiramer Acetate and N-Acetylcysteine in Relapsing-Remitting Multiple Sclerosis

INTRODUCTION

Multiple sclerosis (MS) is an autoimmune disorder of the central nervous system where inflammation and neurodegeneration play key roles. Mounting evidence implicates oxidative stress in the development of irreversible neuronal and glial injury in this condition. N-acetylcysteine (NAC) is a sulfhydryl amino acid derivative with antioxidant and antiapoptotic properties. Administration of NAC to mice attenuated the induction of or improved experimental autoimmune encephalomyelitis (an MS model).

METHODS

We performed an open-label study to explore the tolerability and safety of the combination of glatiramer acetate (GA) and NAC in patients with relapsing-remitting multiple sclerosis at the outpatient MS clinics of the Jewish General Hospital and Hôpital Charles Lemoyne, Montreal, Canada. Seven patients with relapsing-remitting multiple sclerosis with at least one T1 gadolinium-enhancing lesion on screening magnetic resonance imaging were recruited. Treatment consisted of a 10-week run-in period followed by 36-week treatment with a combination of GA 20 mg subcutaneously once daily plus NAC 2.5 g orally twice daily. Outcome measures included safety and tolerability, redox biochemistry, and magnetic resonance imaging effect.

RESULTS

Treatment with the combination of GA and NAC was safe and well tolerated.

CONCLUSIONS

In light of the favorable safety profile, an efficacy-demonstrating study may be considered.

Neuroinflammation and demyelination from the point of nitrosative stress as a new target for neuroprotection

The role of nitrosative stress in the early pathogenesis of neuroinflammation and demyelination is undoubtedly wide. This review summarizes and integrates the results, found in previously performed studies, which have evaluated nitrosative stress participation in neuroinflammation. The largest number of studies indicates that the supply of nitrosative stress inhibitors has led to the opposite clinical effects in experimental studies. Some results claim that attributing the protective role to nitric oxide, outside the total changes of redox oxidative processes and without following the clinical and paraclinical correlates of neuroinflammation, is an overrated role of this mediator. The fact is that the use of nitrosative stress inhibitors would be justified in the earlier phases of neuroinflammation. The ideal choice would be a specific inducible nitric oxide synthase (iNOS) inhibitor, because its use would preserve the physiological features of nitric oxide produced by the effects of constitutive NOS. This review discusses the antinitrosative therapy as a potential mode of therapy that aims to control neuroinflammation in early phases, delaying its later phases, which are accompanied with irreversible neurological disabilities. Some parameters of nitrosative stress might serve as surrogate biomarkers for neuroinflammation intensity and its radiological and clinical correlates.

S-allylmercapto-N-acetylcysteine up-regulates cellular glutathione and protects vascular endothelial cells from oxidative stress

Oxidative stress and/or low cellular glutathione (GSH) levels are associated with the development and progression of numerous pathological conditions. Cells possess various antioxidant protection mechanisms, including GSH and phase II detoxifying enzymes. N-acetylcysteine (NAC) supplies cells with cysteine to increase GSH level but its efficacy is relatively low because of its limited tissue penetration. Allicin (diallyl thiosulfinate), a reactive sulfaorganic compound, increases cellular GSH and phase II detoxifying enzymes in vascular endothelial cells (EC). A novel compound was designed: S-allylmercapto-N-acetylcysteine (ASSNAC), a conjugate of S-allyl mercaptan (a component of allicin) and NAC. Both ASSNAC and NAC increased cellular GSH of ECs, reaching a maximum of up to four- and threefold increase after exposure for 24 or 6 h at a concentration of 0.2 or 1 mM, respectively. ASSNAC induced nuclear translocation of the activated transcription factor Nrf2 and expression of phase II detoxifying enzymes. EC exposure to tBuOOH resulted in 75% cytotoxicity, and pretreatment of cultures with 0.2 mM ASSNAC or 2mM NAC reduced cytotoxicity to 20 and 42%, respectively. In conclusion, ASSNAC is superior to NAC in protecting cells from oxidative stress because of its ability to up-regulate both GSH and the expression of phase II detoxifying enzymes.

Randomized, blinded, placebo-controlled clinical trial of N-acetylcysteine in dogs with spinal cord trauma from acute intervertebral disc disease

STUDY DESIGN

The effect of N-acetylcysteine administration intravenously before hemilaminectomy surgery on neurologic outcome and 15F 2t isoprostane excretion in dogs was examined in a blinded, placebo-controlled trial.

OBJECTIVE

To determine the effect of N-acetylcysteine administration on urinary 15F 2t isoprostane excretion and neurologic outcome following hemilaminectomy for intervertebral disc disease.

SUMMARY OF BACKGROUND DATA

Oxidative stress is a mediator of secondary injury to the spinal cord following trauma. Acute intervertebral disc disease is associated with increased oxidative damage in dogs. N-acetylcysteine has preserved neurologic function following experimental spinal cord injury.

METHODS

Seventy dogs with naturally occurring acute intervertebral disc disease were administered either with saline placebo or N-acetylcysteine intravenously before hemilaminectomy surgery. Serial neurologic examinations were performed before and 1, 2, 7, 14, and 42 days following treatment. Urinary excretion of 15F 2t isoprostane excretion was determined before treatment and 1 hour after surgery.

RESULTS

Analysis of subjective data did not reveal any significant effect of N-acetylcysteine on neurologic outcome or rate of improvement of neurologic score in the 42 days following treatment. Urinary 15F 2t isoprostane excretion was not significantly different between treatment groups (P > 0.05).

CONCLUSION

N-acetylcysteine intravenously before hemilaminectomy has no effect on urinary 15F 2t isoprostane excretion or neurologic outcome. Treatment of dogs with the antioxidant N-acetylcysteine before hemilaminectomy, while not detrimental, does not affect neurologic outcome in the 42 days following surgery.

Oxidative stress and excitotoxicity: a therapeutic issue in multiple sclerosis?

There is increasing evidence that multiple sclerosis (MS) is not only characterized by immune mediated inflammatory reactions but also by neurodegenerative processes. In neurodegenerative diseases, neuronal and axonal loss is mediated by oxidative stress and excitotoxicity which constitute a final common toxic pathway. Importantly, peroxynitrite is the key mediator of those two intertwined pathomechanisms. In MS, peroxynitrite is consistently associated with active lesions and produces highly toxic nitrating and oxidizing radical species that alter lipid, protein, DNA and mitochondrial structures and functions. During the remitting phase, peroxynitrite participates to neuron and oligodendrocyte damage in association with inflammatory processes. During the chronic phase, peroxynitrite contributes to self-perpetuating mechanisms responsible for disease progression. Neutralization of oxidative stress and excitotoxicity, and in particular of peroxynitrite derived free radicals, might represent a therapeutic approach to provide neuroprotection in MS.

Genomics in multiple sclerosis—Current state and future directions

Microarray-based gene expression profiling of large numbers of genes or even the whole genome has only recently become possible. Several studies have employed this technology in multiple sclerosis (MS) and its animal model, experimental allergic encephalomyelitis (EAE), and although results are promising, microarray-based genomics research is still viewed with skepticism. It is often negatively perceived as a fishing expedition rather than a discovery-oriented effort that takes into account the immense complexity of diseases such as MS. Besides these conceptual concerns, technical reproducibility and the strategies to analyze and interpret the massive amounts of data present problems that can cause considerable variability between studies. In this review, we summarize existing data from different gene expression profiling studies that have been conducted in MS and EAE, discuss potential problems and propose future directions for the use of microarrays in MS.

N-acetyl-L-cysteine improves outcome of advanced cerebral adrenoleukodystrophy

Hematopoietic stem cell transplantation as a treatment for childhood cerebral adrenoleukodystrophy (ALD) has historically only been successful in early disease. As ALD is associated with oxidative damage, we reasoned that adjunctive therapy with an antioxidant agent, N-acetyl-L-cysteine (NAC), may provide protection from rapid neurologic decline in boys with advanced cerebral disease. We report three boys with advanced ALD, whose neurologic status and brain radiographic findings were stabilized by treatment including NAC 8-11 months after hematopoietic stem cell transplantation. These results contrast with previous survival data in cerebral ALD patients who had a similar degree of brain involvement, all of whom died within 1 year of stem cell infusion despite a full donor engraftment. Thus, NAC merits investigation as a therapeutic strategy for patients with advanced ALD as an intervention that could change this lethal disease to a condition amendable to treatment with hematopoietic stem cell transplantation.

Experimental encephalomyelitis induces changes in DJ-1: implications for oxidative stress in multiple sclerosis

DJ-1 plays an important role in oxidative stress, and is involved in various neurodegenerative diseases. Accumulating evidence suggests a central role for oxidative stress in multiple sclerosis (MS). The aim of this study was to examine whether changes occur in DJ-1 expression in an animal model of MS, experimental autoimmune encephalomyelitis (EAE). We found upregulation of DJ-1 mRNA and protein expression levels in EAE and a correlation between disease severity and increased DJ-1 levels. Although DJ-1 isoforms were more alkaline in controls, in EAE, a shift was noted toward acidic isoforms. ROS induced by SIN-I exposure led to an increase in DJ-1 mRNA and protein levels in human glioma U-87 cells. Immunocytochemical staining demonstrated that DJ-1 is present both in the cytoplasm and the nuclei of these cells. This is the first report of modulation of DJ-1 expression in EAE. Upregulation of DJ-1 was noted in EAE, and similar results were observed in glioma cells exposed to ROS. In view of the accumulating evidence on the central role of oxidative stress in MS, and the importance of DJ-1 in oxidative stress management by the CNS, we believe that DJ-1 will be found to have a central role in MS.

Antioxidants in multiple sclerosis: do they have a role in therapy?

Multiple sclerosis (MS) is an immune-mediated disease, with inflammation and neurodegeneration contributing to neuronal demyelination and axonal injury. Current therapies for MS are directed toward modulation of the immune response; however, there is increasing evidence that oxidative stress is an important component in the pathogenesis of MS. The inflammatory environment in demyelinating lesions is conducive to the generation of reactive oxygen species. When these species are generated in MS and animal models of MS, products such as peroxynitrite and superoxide are formed that are highly toxic to cells. There are several examples of potential beneficial effects from various antioxidants in animal models of MS, but the efficacy may vary between different agents and, in some instances, may yield deleterious effects. Despite these promising results in animal models, there is limited and conflicting evidence of potential therapeutic effects of antioxidants such as vitamins C and E in treating MS. However, clinical trials in MS patients with more potent antioxidants, identified in animal studies, have been initiated.

Low molecular weight thiol amides attenuate MAPK activity and protect primary neurons from Abeta(1-42) toxicity

Oxidative stress caused by various stimuli lead to oxidation of glutathione (GSH), the major redox power of the cell. Amyloid beta [Abeta(1-42)] is one of the key components of senile plaques and is involved in the progress initiation and triggers of Alzheimer's disease (AD). Lower GSH levels correlated with the activation of mitogen-activated proteins kinases (MAPK) have been demonstrated in AD, Parkinson's disease (PD) and other neurodegenerative disorders and have been proposed to play a central role in the deterioration of the aging and neurodegenerative brain. In this study, we evaluated the ability of low molecular weight thiol amides, N-acetyl cysteine amide (AD4) that replenishes GSH levels, N-acetyl glycine cysteine amide (AD7) and N-acetyl-Cys-Gly-Pro-Cys-amide (CB4) to protect primary neuronal culture against the oxidative and neurotoxic effects of Abeta(1-42) and to inhibit cisplatin- and hydrogen-peroxide-induced phosphorylation of two MAP kinases (MAPK), p38 and ERK1/2, in NIH3T3 cells. Cell death induced by Abeta(1-42) in primary neuronal cells was reversed by the thiol amides. Likewise, protein oxidation, loss of mitochondrial function and DNA fragmentation all returned to control levels by pretreatment with the three thiol amides. Elevated phosphorylation of ERK1/2 and p38 induced by cisplatin or H2O2 in NIH3T3 cells was lowered by AD4, AD7 and CB4 in a dose-dependent manner. Taken together, these results suggest that the thiol amides AD4, AD7 and CB4 protect neuronal cells against Abeta(1-42) toxicity by attenuating oxidative stress in correlation with inhibiting the MAPK phosphorylation cascade. These results are consistent with the notion that these small molecular thiol amides may play a viable protective role in the oxidative and neurotoxicity induced by Abeta(1-42) in AD brain.