In vitro induction of neuronal apoptosis by anti-Fas antibody-containing sera from amyotrophic lateral sclerosis patients

The presence and clinical significance of autoantibodies in amyotrophic lateral sclerosis: a narrative review

Amyotrophic lateral sclerosis (ALS) is a debilitating and rapidly fatal neurodegenerative disease, which is characterized by the selective loss of the upper and lower motor neurons. The pathogenesis of ALS remains to be elucidated and has been connected to genetic, environmental and immune conditions. Evidence from clinical and experimental studies has suggested that the immune system played an important role in ALS pathophysiology. Autoantibodies are essential components of the immune system. Several autoantibodies directed at antigens associated with ALS pathogenesis have been identified in the serum and/or cerebrospinal fluid of ALS patients. The aim of this review is to summarize the presence and clinical significance of autoantibodies in ALS.

Immunology of amyotrophic lateral sclerosis - role of the innate and adaptive immunity

This review aims to summarize the latest evidence about the role of innate and adaptive immunity in Amyotrophic Lateral Sclerosis (ALS). ALS is a devastating neurodegenerative disease affecting upper and lower motor neurons, which involves essential cells of the immune system that play a basic role in innate or adaptive immunity, that can be neurotoxic or neuroprotective for neurons. However, distinguishing between the sole neurotoxic or neuroprotective function of certain cells such as astrocytes can be challenging due to intricate nature of these cells, the complexity of the microenvironment and the contextual factors. In this review, in regard to innate immunity we focus on the involvement of monocytes/macrophages, microglia, the complement, NK cells, neutrophils, mast cells, and astrocytes, while regarding adaptive immunity, in addition to humoral immunity the most important features and roles of T and B cells are highlighted, specifically different subsets of CD4+ as well as CD8+ T cells. The role of autoantibodies and cytokines is also discussed in distinct sections of this review.

ALS plasma reduces the viability of NSC34 cells via altering mRNA expression of VEGF: A short report

Introduction

Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disorder that progressively leads to motor neuron degeneration at the neuromuscular junctions, resulting in paralysis in the patients. The clinical diagnosis of ALS is time taking and further delays the therapeutics that can be helpful if the disease is diagnosed at an early stage. Changes in plasma composition can be reflected upon CSF composition and hence, can be used to study the diagnosis and prognosis markers for the disease.

Aim

To develop a simple model system using motor neuron like cell line after plasma induction.

Method

Neuroblastoma × Spinal Cord hybridoma cell line (NSC34) was cultured under appropriate conditions. 10% ALS patients' plasma was added to the media, and cells were conditioned for 12 h. Cell survival analysis and differential gene expression of a panel of molecules (published previously, VEGF, VEGFR2, ANG, OPTN, TDP43, and MCP-1) were done.

Results

ALS patients' plasma impacted the life of the cells and reduced survival to nearly 50% after induction. VEGF was found to be significantly down-regulated in the cells, which can be explained as a reason for reduced cell survival.

Conclusion

ALS plasma altered the expression of an essential neuroprotective and growth factor VEGF in NSC34 cells leading to reduced viability.

Neuroinflammation in Amyotrophic Lateral Sclerosis and Frontotemporal Dementia and the Interest of Induced Pluripotent Stem Cells to Study Immune Cells Interactions With Neurons

Inflammation is a shared hallmark between amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). For long, studies were conducted on tissues of post-mortem patients and neuroinflammation was thought to be only bystander result of the disease with the immune system reacting to dying neurons. In the last two decades, thanks to improving technologies, the identification of causal genes and the development of new tools and models, the involvement of inflammation has emerged as a potential driver of the diseases and evolved as a new area of intense research. In this review, we present the current knowledge about neuroinflammation in ALS, ALS-FTD, and FTD patients and animal models and we discuss reasons of failures linked to therapeutic trials with immunomodulator drugs. Then we present the induced pluripotent stem cell (iPSC) technology and its interest as a new tool to have a better immunopathological comprehension of both diseases in a human context. The iPSC technology giving the unique opportunity to study cells across differentiation and maturation times, brings the hope to shed light on the different mechanisms linking neurodegeneration and activation of the immune system. Protocols available to differentiate iPSC into different immune cell types are presented. Finally, we discuss the interest in studying monocultures of iPS-derived immune cells, co-cultures with neurons and 3D cultures with different cell types, as more integrated cellular approaches. The hope is that the future work with human iPS-derived cells helps not only to identify disease-specific defects in the different cell types but also to decipher the synergistic effects between neurons and immune cells. These new cellular tools could help to find new therapeutic approaches for all patients with ALS, ALS-FTD, and FTD.

Imaging immunological processes from blood to brain in amyotrophic lateral sclerosis

Neuropathology studies of amyotrophic lateral sclerosis (ALS) and animal models of ALS reveal a strong association between aberrant protein accumulation and motor neurone damage, as well as activated microglia and astrocytes. While the role of neuroinflammation in the pathology of ALS is unclear, imaging studies of the central nervous system (CNS) support the idea that innate immune activation occurs early in disease in both humans and rodent models of ALS. In addition, emerging studies also reveal changes in monocytes, macrophages and lymphocytes in peripheral blood as well as at the neuromuscular junction. To more clearly understand the association of neuroinflammation (innate and adaptive) with disease progression, the use of biomarkers and imaging modalities allow monitoring of immune parameters in the disease process. Such approaches are important for patient stratification, selection and inclusion in clinical trials, as well as to provide readouts of response to therapy. Here, we discuss the different imaging modalities, e.g. magnetic resonance imaging, magnetic resonance spectroscopy and positron emission tomography as well as other approaches, including biomarkers of inflammation in ALS, that aid the understanding of the underlying immune mechanisms associated with motor neurone degeneration in ALS.

Inflammation in ALS/FTD pathogenesis

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative diseases that overlap in their clinical presentation, pathology and genetics, and likely represent a spectrum of one underlying disease. In ALS/FTD patients, neuroinflammation characterized by innate immune responses of tissue-resident glial cells is uniformly present on end-stage pathology, and human imaging studies and rodent models support that neuroinflammation begins early in disease pathogenesis. Additionally, changes in circulating immune cell populations and cytokines are found in ALS/FTD patients, and there is evidence for an autoinflammatory state. However, despite the prominent role of neuro- and systemic inflammation in ALS/FTD, and experimental evidence in rodents that altering microglial function can mitigate pathology, therapeutic approaches to decrease inflammation have thus far failed to alter disease course in humans. Here, we review the characteristics of inflammation in ALS/FTD in both the nervous and peripheral immune systems. We further discuss evidence for direct influence on immune cell function by mutations in ALS/FTD genes including C9orf72, TBK1 and OPTN, and how this could lead to the altered innate immune system “tone” observed in these patients.

Microglia and C9orf72 in neuroinflammation and ALS and frontotemporal dementia

Amyotrophic lateral sclerosis (ALS) is a degenerative disorder that is characterized by loss of motor neurons and shows clinical, pathological, and genetic overlap with frontotemporal dementia (FTD). Activated microglia are a universal feature of ALS/FTD pathology; however, their role in disease pathogenesis remains incompletely understood. The recent discovery that ORF 72 on chromosome 9 (C9orf72), the gene most commonly mutated in ALS/FTD, has an important role in myeloid cells opened the possibility that altered microglial function plays an active role in disease. This Review highlights the contribution of microglia to ALS/FTD pathogenesis, discusses the connection between autoimmunity and ALS/FTD, and explores the possibility that C9orf72 and other ALS/FTD genes may have a "dual effect" on both neuronal and myeloid cell function that could explain a shared propensity for altered systemic immunity and neurodegeneration.

Non-neuronal Cells in ALS: Role of Glial, Immune cells and Blood-CNS Barriers

Neurological dysfunction and motor neuron degeneration in amyotrophic lateral sclerosis (ALS) is strongly associated with neuroinflammation reflected by activated microglia and astrocytes in the CNS. In ALS endogenous triggers in the CNS such as aggregated protein and misfolded proteins activate a pathogenic response by innate immune cells. However, there is also strong evidence for a neuroprotective immune response in ALS. Emerging evidence also reveals changes in the peripheral adaptive immune responses as well as alterations in the blood brain barrier that may aid traffic of lymphocytes and antibodies into the CNS. Understanding the triggers of neuroinflammation is key to controlling neuronal loss. Here, we review the current knowledge regarding the roles of non-neuronal cells as well as the innate and adaptive immune responses in ALS. Existing ALS animal models, in particular genetic rodent models, are very useful to study the underlying pathogenic mechanisms of motor neuron degeneration. We also discuss the approaches used to target the pathogenic immune responses and boost the neuroprotective immune pathways as novel immunotherapies for ALS.

Histological changes in the rat brain and spinal cord following prolonged intracerebroventricular infusion of cerebrospinal fluid from amyotrophic lateral sclerosis patients are similar to those caused by the disease

INTRODUCTION

Cerebrospinal fluid (CSF) from amyotrophic lateral sclerosis (ALS) patients induces cytotoxic effects in in vitro cultured motor neurons.

MATERIAL AND METHODS

We selected CSF with previously reported cytotoxic effects from 32 ALS patients. Twenty-eight adult male rats were intracerebroventricularly implanted with osmotic mini-pumps and divided into 3 groups: 9 rats injected with CSF from non-ALS patients, 15 rats injected with cytotoxic ALS-CSF, and 4 rats injected with a physiological saline solution. CSF was intracerebroventricularly and continuously infused for periods of 20 or 43days after implantation. We conducted clinical assessments and electromyographic examinations, and histological analyses were conducted in rats euthanised 20, 45, and 82days after surgery.

RESULTS

Immunohistochemical studies revealed tissue damage with similar characteristics to those found in the sporadic forms of ALS, such as overexpression of cystatinC, transferrin, and TDP-43 protein in the cytoplasm. The earliest changes observed seemed to play a protective role due to the overexpression of peripherin, AKTpan, AKTphospho, and metallothioneins; this expression had diminished by the time we analysed rats euthanised on day 82, when an increase in apoptosis was observed. The first cellular changes identified were activated microglia followed by astrogliosis and overexpression of GFAP and S100B proteins.

CONCLUSION

Our data suggest that ALS could spread through CSF and that intracerebroventricular administration of cytotoxic ALS-CSF provokes changes similar to those found in sporadic forms of the disease.

Axotomy-induced target disconnection promotes an additional death mechanism involved in motoneuron degeneration in amyotrophic lateral sclerosis transgenic mice

The target disconnection theory of amyotrophic lateral sclerosis (ALS) pathogenesis suggests that disease onset is initiated by a peripheral pathological event resulting in neuromuscular junction loss and motoneuron (MN) degeneration. Presymptomatic mSOD1(G93A) mouse facial MN (FMN) are more susceptible to axotomy-induced cell death than wild-type (WT) FMN, which suggests additional CNS pathology. We have previously determined that the mSOD1 molecular response to facial nerve axotomy is phenotypically regenerative and indistinguishable from WT, whereas the surrounding microenvironment shows significant dysregulation in the mSOD1 facial nucleus. To elucidate the mechanisms underlying the enhanced mSOD1 FMN loss after axotomy, we superimposed the facial nerve axotomy model on presymptomatic mSOD1 mice and investigated gene expression for death receptor pathways after target disconnection by axotomy vs. disease progression. We determined that the TNFR1 death receptor pathway is involved in axotomy-induced FMN death in WT and is partially responsible for the mSOD1 FMN death. In contrast, an inherent mSOD1 CNS pathology resulted in a suppressed glial reaction and an upregulation in the Fas death pathway after target disconnection. We propose that the dysregulated mSOD1 glia fail to provide support the injured MN, leading to Fas-induced FMN death. Finally, we demonstrate that, during disease progression, the mSOD1 facial nucleus displays target disconnection-induced gene expression changes that mirror those induced by axotomy. This validates the use of axotomy as an investigative tool in understanding the role of peripheral target disconnection in the pathogenesis of ALS.

Effect of ALS IgG on Motor Neurons in Organotypic Spinal Cord Cultures

Objective:

Reports about the role of autoimmunity in amyotrophic lateral sclerosis (ALS) are inconsistent. The aim of this work was to investigate the effect of IgG from patients with ALS on motor neurons in a physiological-like surrounding.

Methods:

Using affinity chromatography, IgG from six ALS patients, four disease controls and five healthy subjects was purified. Organotypic spinal cord cultures, which conserve the structure of the spinal cord in a horizontal plane and are suitable for studies with long-term treatment, were used and IgG with different concentrations ranging from 0.05 mg/mL to 0.5 mg/mL was added to the culture medium. Ventral motor neuron survival was evaluated by morphology and SMI-32 immunohistochemistry staining. Lactate dehydrogenase (LDH) level in the culture medium was measured by colorimetry.

Results:

After cultures were treated with ALS IgG for three weeks, the number and morphology of motor neurons showed little change. In addition, there was no significant difference in lactate dehydrogenase release between cultures treated with medium alone, normal control IgG, disease control IgG or ALS IgG.

Conclusions:

The results indicate that IgG from these ALS patients was insufficient per se to induce motor neuron death in Organotypic slice cultures. However, this does not preclude the possibility that other changes may have occurred in the motor neurons. This work offered a new model to evaluate the role of IgG in the pathogenesis of ALS. Organotypic cultures contribute to study of the impact of IgG on motor neurons by mimicking physiological conditions.

Novel molecular biomarkers at the blood-brain barrier in ALS

Recently neuroinflammation has gained a particular focus as a key mechanism of ALS. Several studies in vivo as well as in vitro have nominated immunoglobulin G (IgG) isolated from ALS patients as an active contributor to disease onset and progression. We have shown that ALS IgG affects astroglial Ca²⁺ excitability and induces downstream activation of phosphatidylinositol 3-kinase. These studies were hampered by a lack of knowledge of the pathway of entry of immune factors in the CNS. Our MRI data revealed the blood-brain barrier BBB leakage and T cell infiltration into brain parenchyma in ALS G93A rats. Since astrocyte ensheathes blood vessel wall contributing to BBB stability and plays an important role in ALS pathogenesis, we have studied astrocytic membrane proteins water channel aquaporin-4 and the inwardly rectifying potassium channel. In this review, we will summarize data related to BBB disruption with particular emphasis on impaired function of astrocytes in ALS. We will discuss implication of membrane proteins expressed on astrocytic endfeet, aquaporin-4, and inwardly rectifying potassium channel in the pathology of ALS. In addition to ALS-specific IgGs, these membrane proteins are proposed as novel biomarkers of the disease.

Highly immunoreactive IgG antibodies directed against a set of twenty human proteins in the sera of patients with amyotrophic lateral sclerosis identified by protein array

Amyotrophic lateral sclerosis (ALS), the most common adult-onset motor neuron disorder, is characterized by the progressive and selective loss of upper and lower motor neurons. Diagnosis of this disorder is based on clinical assessment, and the average survival time is less than 3 years. Injections of IgG from ALS patients into mice are known to specifically mark motor neurons. Moreover, IgG has been found in upper and lower motor neurons in ALS patients. These results led us to perform a case-control study using human protein microarrays to identify the antibody profiles of serum samples from 20 ALS patients and 20 healthy controls. We demonstrated high levels of 20 IgG antibodies that distinguished the patients from the controls. These findings suggest that a panel of antibodies may serve as a potential diagnostic biomarker for ALS.

Neuroimmunity dynamics and the development of therapeutic strategies for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal paralytic disorder characterized by the progressive and selective loss of both upper and lower motoneurons. The neurodegenerative process is accompanied by a sustained inflammation in the brain and spinal cord. The neuron-immune interaction, implicating resident microglia of the central nervous system and blood-derived immune cells, is highly dynamic over the course of the disease. Here, we discuss the timely controlled neuroprotective and neurotoxic cues that are provided by the immune environment of motoneurons and their potential therapeutic applications for ALS.

Transcriptomic indices of fast and slow disease progression in two mouse models of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is heterogeneous with high variability in the speed of progression even in cases with a defined genetic cause such as superoxide dismutase 1 (SOD1) mutations. We reported that SOD1(G93A) mice on distinct genetic backgrounds (C57 and 129Sv) show consistent phenotypic differences in speed of disease progression and life-span that are not explained by differences in human SOD1 transgene copy number or the burden of mutant SOD1 protein within the nervous system. We aimed to compare the gene expression profiles of motor neurons from these two SOD1(G93A) mouse strains to discover the molecular mechanisms contributing to the distinct phenotypes and to identify factors underlying fast and slow disease progression. Lumbar spinal motor neurons from the two SOD1(G93A) mouse strains were isolated by laser capture microdissection and transcriptome analysis was conducted at four stages of disease. We identified marked differences in the motor neuron transcriptome between the two mice strains at disease onset, with a dramatic reduction of gene expression in the rapidly progressive (129Sv-SOD1(G93A)) compared with the slowly progressing mutant SOD1 mice (C57-SOD1(G93A)) (1276 versus 346; Q-value ≤ 0.01). Gene ontology pathway analysis of the transcriptional profile from 129Sv-SOD1(G93A) mice showed marked downregulation of specific pathways involved in mitochondrial function, as well as predicted deficiencies in protein degradation and axonal transport mechanisms. In contrast, the transcriptional profile from C57-SOD1(G93A) mice with the more benign disease course, revealed strong gene enrichment relating to immune system processes compared with 129Sv-SOD1(G93A) mice. Motor neurons from the more benign mutant strain demonstrated striking complement activation, over-expressing genes normally involved in immune cell function. We validated through immunohistochemistry increased expression of the C3 complement subunit and major histocompatibility complex I within motor neurons. In addition, we demonstrated that motor neurons from the slowly progressing mice activate a series of genes with neuroprotective properties such as angiogenin and the nuclear factor (erythroid-derived 2)-like 2 transcriptional regulator. In contrast, the faster progressing mice show dramatically reduced expression at disease onset of cell pathways involved in neuroprotection. This study highlights a set of key gene and molecular pathway indices of fast or slow disease progression which may prove useful in identifying potential disease modifiers responsible for the heterogeneity of human amyotrophic lateral sclerosis and which may represent valid therapeutic targets for ameliorating the disease course in humans.

Death Receptors in the Selective Degeneration of Motoneurons in Amyotrophic Lateral Sclerosis

While studies on death receptors have long been restricted to immune cells, the last decade has provided a strong body of evidence for their implication in neuronal death and hence neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS). ALS is a fatal paralytic disorder that primarily affects motoneurons in the brain and spinal cord. A neuroinflammatory process, associated with astrocyte and microglial activation as well as infiltration of immune cells, accompanies motoneuron degeneration and supports the contribution of non-cell-autonomous mechanisms in the disease. Hallmarks of Fas, TNFR, LT-βR, and p75^NTR signaling have been observed in both animal models and ALS patients. This review summarizes to date knowledge of the role of death receptors in ALS and the link existing between the selective loss of motoneurons and neuroinflammation. It further suggests how this recent evidence could be included in an ultimate multiapproach to treat patients.

Immunoglobulins G from patients with sporadic amyotrophic lateral sclerosis affects cytosolic Ca2+ homeostasis in cultured rat astrocytes

Astrocytes are considered essential in the etiopathogenesis of amyotrophic lateral sclerosis (ALS). We have demonstrated previously that immunoglobulins G (IgG) isolated from patients with ALS enhance the mobility of acidic vesicles in cultured astrocytes in a Ca(2+)-dependent manner. Here we directly examined the impact of purified sporadic ALS IgG on cytosolic [Ca(2+)] ([Ca(2+)]i) in astrocytes. Confocal time-lapse images were acquired and fluorescence of a non-ratiometric Ca(2+) indicator was recorded before and after the application of IgG. ALS IgG (0.1 mg/ml) from 7 patients evoked transient increases in [Ca(2+)]i in ~50% of tested astrocytes. The probability of observing a response was independent of extracellular Ca(2+). The peak increase in [Ca(2+)]i developed ~3 times faster and the time integral of evoked transients was ~2-fold larger; the peak amplitude itself was not affected by extracellular Ca(2+). Application of pharmacological inhibitors revealed that activation of inositol-1,4,5-triphosphate receptors is necessary and sufficient to initiate transients in [Ca(2+)]i; the Ca(2+) influx through store-operated calcium entry prolongs the transient increase in [Ca(2+)]i. Thus, ALS IgG acutely affect [Ca(2+)]i by mobilizing both, intra- and extracellular Ca(2+) into the cytosol of cultured astrocytes.

Chloride channel blocker 4,4-diisothiocyanatostilbene-2,2'-disulfonic acid inhibits nitric oxide-induced apoptosis in cultured rat hippocampal neurons

Apoptosis in cultured rat hippocampal neurons was induced using the nitric oxide donor 3-morpholinosydnonimine, and cells were treated with the chloride channel blocker, 4,4-diisothiocyanatostilbene-2,2′-disulfonic acid. Results showed that the survival rate of neurons was significantly increased after treatment with 4,4-diisothiocyanatostilbene-2,2′-disulfonic acid, and the rate of apoptosis decreased. In addition, the expression of the apoptosis-related proteins poly(adenosine diphosphate-ribose)polymerase-1 and apoptosis-inducing factor were significantly reduced. Our experimental findings indicate that the chloride channel blocker 4,4-diisothiocyanatostilbene-2,2′-disulfonic acid can antagonize apoptotic cell death of hippocampal neurons by inhibiting the expression of the apoptosis-related proteins poly(adenosine diphosphate-ribose)polymerase-1 and apoptosis-inducing factor.

Glycans in sera of amyotrophic lateral sclerosis patients and their role in killing neuronal cells

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease caused by degeneration of upper and lower motor neurons. To date, glycosylation patterns of glycoproteins in fluids of ALS patients have not been described. Moreover, the aberrant glycosylation related to the pathogenesis of other neurodegenerative diseases encouraged us to explore the glycome of ALS patient sera. We found high levels of sialylated glycans and low levels of core fucosylated glycans in serum-derived N-glycans of patients with ALS, compared to healthy volunteer sera. Based on these results, we analyzed the IgG Fc N²⁹⁷-glycans, as IgG are major serum glycoproteins affected by sialylation or core fucosylation and are found in the motor cortex of ALS patients. The analyses revealed a distinct glycan, A2BG2, in IgG derived from ALS patient sera (ALS-IgG). This glycan increases the affinity of IgG to CD16 on effector cells, consequently enhancing Antibody-Dependent Cellular Cytotoxicity (ADCC). Therefore, we explore whether the Fc-N²⁹⁷-glycans of IgG may be involved in ALS disease. Immunostaining of brain and spinal cord tissues revealed over-expression of CD16 and co-localization of intact ALS-IgG with CD16 and in brain with activated microglia of G93A-SOD1 mice. Intact ALS-IgG enhanced effector cell activation and ADCC reaction in comparison to sugar-depleted or control IgG. ALS-IgG were localized in the synapse between brain microglia and neurons of G93A-SOD1 mice, manifesting a promising in vivo ADCC reaction. Therefore, glycans of ALS-IgG may serve as a biomarker for the disease and may be involved in neuronal damage.

Elevated levels of IFNγ and LIGHT in the spinal cord of patients with sporadic amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a paralytic and fatal neurodegenerative disorder caused by the gradual loss of both upper and lower motoneurons. There is compelling evidence from ALS experimental models that neuroinflammation actively contributes to motoneuron damage. We recently proposed that interferon gamma (IFNγ), a potent proinflammatory cytokine, induces motoneuron death by eliciting the activation of the lymphotoxin beta receptor (LT-βR) through its ligand LIGHT. Here, we explore the pertinence of this non-cell-autonomous mechanism in human ALS.

METHODS

The levels and expression pattern of IFNγ, LIGHT, and LT-βR were investigated by Western blot and immunohistochemical analysis in spinal cord of patients with sporadic ALS.

RESULTS

  We observed significant increased levels of IFNγ in human ALS spinal cords compared to control cases. We found that large ventral horn neurons as well as glial cells were immunoreactive for IFNγ in sporadic ALS spinal cord. We further observed that LIGHT and LT-βR were expressed mainly by motoneurons in both ALS and control cases, and while LT-βR levels remained constant between ALS and control cases, LIGHT levels were increased in human ALS spinal cords.

CONCLUSION

These findings in sporadic ALS cases, which are consistent with the observation made in ALS experimental models, propose that the IFNγ-triggered LIGHT/LT-βR-mediated death pathway may contribute to human ALS pathogenesis.

Amyotrophic lateral sclerosis immunoglobulins G enhance the mobility of Lysotracker-labelled vesicles in cultured rat astrocytes

AIM

We examined the effect of purified immunoglobulins G (IgG) from patients with amyotrophic lateral sclerosis (ALS) on the mobility and exocytotic release from Lysotracker-stained vesicles in cultured rat astrocytes.

METHODS

Time-lapse confocal images were acquired, and vesicle mobility was analysed before and after the application of ALS IgG. The vesicle counts were obtained to assess cargo exocytosis from stained organelles.

RESULTS

At rest, when mobility was monitored for 2 min in bath with Ca(2+), two vesicle populations were discovered: (1) non-mobile vesicles (6.1%) with total track length (TL) < 1 μm, averaging at 0.33 ± 0.01 μm (n = 1305) and (2) mobile vesicles (93.9%) with TL > 1 μm, averaging at 3.03 ± 0.01 μm (n = 20,200). ALS IgG (0.1 mg mL(-1)) from 12 of 13 patients increased the TL of mobile vesicles by approx. 24% and maximal displacement (MD) by approx. 26% within 4 min, while the IgG from control group did not alter the vesicle mobility. The mobility enhancement by ALS IgG was reduced in extracellular solution devoid of Ca(2+), indicating that ALS IgG vesicle mobility enhancement involves changes in Ca(2+) homeostasis. To examine whether enhanced mobility relates to elevated Ca(2+) activity, cells were stimulated by 1 mm ATP, a cytosolic Ca(2+) increasing agent, in the presence (2 mm) and in the absence of extracellular Ca(2+). ATP stimulation triggered an increase in TL by approx. 7% and 12% and a decrease in MD by approx. 11% and 1%, within 4 min respectively. Interestingly, none of the stimuli triggered the release of vesicle cargo.

CONCLUSION

Amyotrophic lateral sclerosis-IgG-enhanced vesicle mobility in astrocytes engages changes in calcium homeostasis.

Serum caspase-9 levels are increased in patients with amyotrophic lateral sclerosis

It is known that apoptosis may play a role in the pathophysiology of amyotrophic lateral sclerosis (ALS). Moreover, caspase-9 is implicated in the apoptosis pathway. The aim of the study was to investigate caspase-9 levels in serum of patients with ALS. The study involved 30 patients with ALS and 30 patients from the control group. The serum caspase-9 levels were measured using the enzyme-linked immunosorbent method. The study showed that caspase-9 levels are significantly increased in serum of the patients with ALS comparing to the control group (p < 0.05). There was a significant correlation of serum caspase-9 levels with severity of clinical state of ALS patients and duration of the disease (p < 0.05). The results indicate that caspase-9 may be implicated in pathomechanism of neurodegeneration in ALS.

Autoimmunity in amyotrophic lateral sclerosis: past and present

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting particularly motor neurons for which no cure or effective treatment is available. Although the cause of ALS remains unknown, accumulative evidence suggests an autoimmune mechanism of pathogenesis. In this paper, we will summarize the current research related to autoimmunity in the sporadic form of ALS and discuss the potential underlying pathogenic mechanisms and perspectives. Presented data supports the view that humoral immune responses against motor nerve terminals can initiate a series of physiological changes leading to alteration of calcium homeostasis. In turn, loss of calcium homeostasis may induce neuronal death through apoptotic signaling pathways. Additional approaches identifying specific molecular features of this hypothesis are required, which will hopefully allow us to develop techniques of early diagnosis and effective therapies.

Effect of genetic background on phenotype variability in transgenic mouse models of amyotrophic lateral sclerosis: a window of opportunity in the search for genetic modifiers

Transgenic (Tg) mouse models of FALS containing mutant human SOD1 genes (G37R, G85R, D90A, or G93A missense mutations or truncated SOD1) exhibit progressive neurodegeneration of the motor system that bears a striking resemblance to ALS, both clinically and pathologically. The most utilized and best characterized Tg mice are the G93A mutant hSOD1 (Tg(hSOD1-G93A)1GUR mice), abbreviated G93A. In this review we highlight what is known about background-dependent differences in disease phenotype in transgenic mice that carry mutated human or mouse SOD1. Expression of G93A-hSOD1Tg in congenic lines with ALR, NOD.Rag1KO, SJL or C3H backgrounds show a more severe phenotype than in the mixed (B6xSJL) hSOD1Tg mice, whereas a milder phenotype is observed in B6, B10, BALB/c and DBA inbred lines. We hypothesize that the background differences are due to disease-modifying genes. Identification of modifier genes can highlight intracellular pathways already suspected to be involved in motor neuron degeneration; it may also point to new pathways and processes that have not yet been considered. Most importantly, identified modifier genes provide new targets for the development of therapies.

Immune system alterations in sporadic amyotrophic lateral sclerosis patients suggest an ongoing neuroinflammatory process

In this work we show that patients with sporadic amyotrophic lateral sclerosis exhibit immunological alterations in their blood, with respect to healthy controls, such as: i) increased levels of CD4+ cells and decreased levels of CD8+ T lymphocytes, the latter due to the reduced expression of the anti-apoptotic molecule Bcl-2; ii) significantly reduced CD4+CD25+ regulatory T (Treg) cells and monocytes (CD14+) levels in patients at a less severe stage of disease, suggesting their early recruitment towards the CNS area of primary neurodegeneration; iii) reduced expression of HLA-DR and CCR2 expression, as markers of activation, in monocytes. Since resident microglia partially derives from circulating activated monocytes and Treg cells are known to interact with the local microglia, this study strengthens the hypothesis of an involvement of the adaptive immune system associated with a neuroinflammatory process in the pathobiology of ALS.

Protective effect of memantine against Doxorubicin toxicity in primary neuronal cell cultures: influence a development stage

One of the serious unwanted effects of the anthracycline anticancer drug doxorubicin (Dox, adriamycin) is its neurotoxicity, which can be evoked by the activation of extracellular (FAS/CD95/Apo-1) pathway of apoptosis in cells. Since memantine, a clinically used N-methyl-D: -aspartic acid (NMDA) receptor antagonist, shows antiapoptotic action in several models of neuronal cell damage, in this study we evaluated the effect of memantine on the cell death induced by Dox in primary neuronal cell cultures. First, we investigated the effect of different concentrations of Dox (0.1-5 microM) on mouse neocortical, hippocampal, striatal, and cerebellar neurons on 7- and 12-day in vitro (DIV). The 7 DIV neuronal cell cultures were more prone to Dox-induced cell death than 12 DIV cultures. The cerebellar neurons were the most resistant to Dox-induced apoptosis in comparison to neuronal cell cultures derived from the forebrain. Memantine (0.1-2 microM) attenuated the Dox-evoked lactate dehydrogenase release in 7 DIV neuronal cell cultures with no significant effect on 12 DIV cultures. The ameliorating effect of memantine on Dox-mediated cell death was also confirmed by an increase in cell viability measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay. There was no effect of memantine on Dox-induced caspase-8 and -3 activity and Dox-evoked decrease in mitochondrial potential, although attenuation in the number of cells with apoptotic DNA fragmentation was observed. We also showed that the antiapoptotic effect of memantine in our model was NMDA receptor-independent, since two other antagonists of this receptor, MK-801 and AP-5, did not attenuate Dox-induced cell death. Furthermore, memantine did not influence the Dox-evoked increase in cytoplasmic Ca2+ level. The obtained data suggest developmental regulation of both, the Dox-mediated neurotoxicity and efficacy of memantine in alleviating the Dox-induced cell damage in neuronal cell cultures. Moreover, this neuroprotective effect of memantine seems not to be dependent on caspase-3 activity and on the antagonistic action on NMDA receptor.

Modulation of Fas-induced apoptosis by p75 neurotrophin receptor in a human neuroblastoma cell line

Fas and p75 neurotrophin receptors (p75(NTR)) are death receptors that alone induce apoptosis of SH-SY5Y neuroblastoma cell line respectively by Fas ligand or brain-derived neurotrophic factor (BDNF, a p75(NTR) ligand). We report on the modulation of Fas-mediated apoptosis by concomitant p75(NTR) activation. The exposure to both ligands suppressed the apoptotic effect. A co-localisation of Fas and p75(NTR) receptors was evidenced by co-capping and immunoprecipitation assays. Moreover, a caspase-8 inhibitor suppressed the protective effect of the concomitant BDNF and Fas ligand stimulation, suggesting that p75(NTR) and Fas receptors could share common signalling pathways.

Fas small interfering RNA reduces motoneuron death in amyotrophic lateral sclerosis mice

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a progressive, fatal neurodegenerative disease characterized by selective motoneuron death. Understanding of the molecular mechanisms that trigger and regulate motoneuron degeneration could be relevant to ALS and other motoneuron disorders. This study investigates the role of Fas-linked motoneuron death in the pathogenesis of ALS.

METHODS

We performed in vitro and in vivo small interfering RNA-mediated interference, by silencing the Fas receptor on motoneurons that carry the superoxide dismutase-1 (SOD1)-G93A mutation.

RESULTS

We observed a significant reduction in Fas expression at messenger RNA (p < 0.001) and protein levels. Treated motoneurons demonstrated an increase in survival and a reduction in cytochrome c release from mitochondria. In vivo, continuous intrathecal administration of Fas small interfering RNA by an osmotic minipump improved motor function and survival in SOD1-G93A mice (mean increase, 18 days; p < 0.0001). Treated mice showed a significant reduction in Fas and Fas mediators p38 mitogen-activated protein kinase, neuronal nitric oxide synthase, and caspase-8.

INTERPRETATION

Fas silencing interferes with motoneuron-specific downstream death pathways and results in increased motoneuron survival and amelioration of the SOD1-G93A phenotype, suggesting new possible strategies for molecular therapy of ALS.

Expression of L-type calcium channel alpha(1)-1.2 and alpha(1)-1.3 subunits on rat sacral motoneurons following chronic spinal cord injury

In the presence of the monoamines serotonin and norepinephrine, motoneurons readily generate large persistent inward currents (PICs). The resulting plateau potentials amplify and sustain motor output. Monoaminergic input to the cord originates in the brainstem and the sharp reduction in monoamine levels that occurs following acute spinal cord injury greatly decreases motoneuron excitability. However, recent studies in the adult sacral cord of the rat have shown that motoneurons reacquire the ability to generate PICs and plateau potentials within 1-2 months following spinal transection. Ca(v)1.3 L-type calcium channels are involved in generating PICs in both healthy and injured animals. Additionally, expression of Ca(v)1.2 and Ca(v)1.3 L-type calcium channels is altered in several pathological conditions. Therefore, in this paper we analyzed the expression of L-type calcium channel alpha(1) subunits within the motoneuron pool following a complete transection of the spinal cord at the level of the sacral vertebra (S)2 segment. The analysis was done both caudally (S4 segment) and rostrally [thoracic vertebra (T)6 segment] from the injury site. The S4 segment was significantly reduced in diameter when compared with control animals, and this reduction was more evident in the white matter. Ca(v)1.2 alpha(1) subunit expression significantly increased (26%) in the motoneuron pool located caudally but not rostrally from the injury site. In contrast, the expression of Ca(v)1.3 alpha(1) subunit remained unchanged in both S4 and T6 segments. The differential expression of the two alpha(1) subunits in spinal injury suggests that Ca(v)1.2 and Ca(v)1.3 channels have different functions in neuronal adaptation following spinal cord injury.

Pathways and genes differentially expressed in the motor cortex of patients with sporadic amyotrophic lateral sclerosis

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal disorder caused by the progressive degeneration of motoneurons in brain and spinal cord. Despite identification of disease-linked mutations, the diversity of processes involved and the ambiguity of their relative importance in ALS pathogenesis still represent a major impediment to disease models as a basis for effective therapies. Moreover, the human motor cortex, although critical to ALS pathology and physiologically altered in most forms of the disease, has not been screened systematically for therapeutic targets.

RESULTS

By whole-genome expression profiling and stringent significance tests we identify genes and gene groups de-regulated in the motor cortex of patients with sporadic ALS, and interpret the role of individual candidate genes in a framework of differentially expressed pathways. Our findings emphasize the importance of defense responses and cytoskeletal, mitochondrial and proteasomal dysfunction, reflect reduced neuronal maintenance and vesicle trafficking, and implicate impaired ion homeostasis and glycolysis in ALS pathogenesis. Additionally, we compared our dataset with publicly available data for the SALS spinal cord, and show a high correlation of changes linked to the diseased state in the SALS motor cortex. In an analogous comparison with data for the Alzheimer's disease hippocampus we demonstrate a low correlation of global changes and a moderate correlation for changes specifically linked to the SALS diseased state.

CONCLUSION

Gene and sample numbers investigated allow pathway- and gene-based analyses by established error-correction methods, drawing a molecular portrait of the ALS motor cortex that faithfully represents many known disease features and uncovers several novel aspects of ALS pathology. Contrary to expectations for a tissue under oxidative stress, nuclear-encoded mitochondrial genes are uniformly down-regulated. Moreover, the down-regulation of mitochondrial and glycolytic genes implies a combined reduction of mitochondrial and cytoplasmic energy supply, with a possible role in the death of ALS motoneurons. Identifying candidate genes exclusively expressed in non-neuronal cells, we also highlight the importance of these cells in disease development in the motor cortex. Notably, some pathways and candidate genes identified by this study are direct or indirect targets of medication already applied to unrelated illnesses and point the way towards the rapid development of effective symptomatic ALS therapies.

Increase of Fas-induced apoptosis by inhibition of extracellular phosphorylation of Fas receptor in Jurkat cell line

Apoptosis signalling through the Fas pathway requires several steps of aggregation of the Fas receptor in the membrane, including aggregation that may occur in the absence of Fas ligand. Association of Fas domains is determinant to signal transmission following Fas ligand binding to a specific domain. The domains involved in Fas aggregation are located in its extracellular region and contain three potential protein kinase C-binding motifs. We therefore studied the possibility that phosphorylation of the extracellular region of Fas might be implicated in the regulation of Fas-mediated apoptosis. Inhibition experiments of extracellular phosphorylation were performed in human Jurkat T leukemia cells with K252b, an impermeant protein-kinase inhibitor. Extracellular phosphorylation of Fas receptor was related to ecto-kinase, as assessed by the [gamma-(32)P] ATP labelling of Fas-116 kDa aggregates, suppressed by K252b inhibitor which significantly increased the sensitivity to Fas-mediated apoptosis. Ecto-PKC involvement was demonstrated by bisindolylmaleimide VIII, a selective inhibitor of protein kinase C which significantly increased both Fas aggregation in the membrane and Fas-mediated apoptosis and by the addition of the PKC pseudo-substrate 19-36 which inhibited the phosphorylation of 116 kDa Fas aggregates. These data support a role for Fas phosphorylation in the decreased sensitivity to apoptosis in the Jurkat T leukemia cell line.

Serine proteases purified from sera of patients with amyotrophic lateral sclerosis (ALS) induce contrasting cytopathology in murine motoneurones to IgG

Affinity purified IgG from sera of patients with amyotrophic lateral sclerosis (ALS) is claimed to enhance transmitter release, induce apoptotic death of cultured motoneurones, and elicit a distinctive cytopathology with raised Ca(2+) in mouse motoneurones. An alternative hypothesis attributes these events to serine proteases in ALS sera. To test this, motoneurones in BALB/c mice injected intraperitoneally with plasminogen affinity purified from sera of ALS patients and healthy controls were analysed using immunochemical and ultrastructural morphometric methods. The responses were validated in motoneurones of mice injected with commercially purified plasminogen, tissue plasminogen activator (tPA), or plasmin. Motoneurones in non-injected mice had normal morphology and ultrastructure without evidence of electron-dense degeneration. Purified plasminogen from both ALS patients and healthy controls, evoked electron-dense motoneurone degeneration, as did commercially purified plasminogen and tPA. The common cytopathology comprised disruption and distension of Nissl body rough endoplasmic reticulum, cytoplasmic polyribosomal proliferation, and significant Ca(2+) enhancement in mitochondria. By contrast, using affinity purified serum immunoglobulins, ALS-IgG but not IgG from healthy or disease controls, elicited necrosis, with 30% of ALS-IgGs tested evoking electron-dense degeneration in 40% of motoneurones. The primary cytopathology was extensive swelling of Golgi endoplasmic reticulum and mitochondria, with enhancement of Ca(2+) in Golgi endoplasmic reticulum and presynaptic boutons. We conclude that serine proteases purified from sera of ALS patients elicits a distinctive cytopathology and pattern of Ca(2+) enhancement in motoneurones different from that found on passive transfer of affinity purified ALS-IgG.

Chronic activation in presymptomatic amyotrophic lateral sclerosis (ALS) mice of a feedback loop involving Fas, Daxx, and FasL

The reasons for the cellular specificity and slow progression of motoneuron diseases such as ALS are still poorly understood. We previously described a motoneuron-specific cell death pathway downstream of the Fas death receptor, in which synthesis of nitric oxide (NO) is an obligate step. Motoneurons from ALS model mice expressing mutant SOD1 showed increased susceptibility to exogenous NO as compared with controls. Here, we report a signaling mechanism whereby NO leads to death of mutant, but not control, motoneurons. Unexpectedly, exogenous NO triggers expression of Fas ligand (FasL) in cultured motoneurons. In mutant SOD1(G93A) and SOD1(G85R), but not in control motoneurons, this up-regulation results in activation of Fas, leading through Daxx to phosphorylation of p38 and further NO synthesis. This Fas/NO feedback amplification loop is required for motoneuron death in vitro. In vivo, mutant SOD1(G93A) and SOD1(G85R) mice show increased numbers of positive motoneurons and Daxx nuclear bodies weeks before disease onset. Moreover, FasL up-regulation is reduced in the presence of transgenic dominant-negative Daxx. We propose that chronic low-level activation of the Fas/NO feedback loop may underlie the motoneuron loss that characterizes familial ALS and may help to explain its slowly progressive nature.

Detection, epitope-mapping and function of anti-Fas autoantibody in patients with silicosis

Dysregulation of apoptosis through the Fas-Fas ligand pathway is associated with the onset of autoimmune disease. Since autoantibodies directed against unknown antigens are present in the sera of these patients, sera samples were examined for the presence of autoantibodies directed against the Fas molecule. Using Western blotting and a ProteinChip analysis, autoantibodies against Fas were detected in patients with silicosis, systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), and weakly detected in healthy individuals. Using epitope mapping employing 12-amino-acid polypeptides with the SPOTs system, a minimum of four epitopes and a maximum of 10 epitopes were found. Several amino acid residues involved in binding FasL, such as C66, R87, L90, E93 and H126, were presented within the epitopes. Serum containing a large amount of anti-Fas autoantibody from silicosis patients inhibited the growth of a Fas-expressing human cell line, but did not inhibit the growth of a low Fas-expresser nor a Fas-expresser in which the Fas gene had been silenced by small interference RNA. All epitopes in the intracellular region of Fas were located in the death domain. The possible roles of anti-Fas autoantibody detected in healthy volunteers and patients with silicosis or autoimmune diseases are discussed here.

ALS-IgG-induced selective motor neurone apoptosis in rat mixed primary spinal cord cultures

There is evidence that in sporadic amyotrophic lateral sclerosis (ALS) immunological mechanisms may be involved in the pathophysiology of the disease. We tested whether purified IgG from ALS patients induce cell death in rat mixed primary spinal cord cultures and compared this with the effect of IgG purified from patients with Guillain-Barré syndrome (GBS) or from healthy donors. Treatment with ALS-IgG increases caspase-3 apoptosis when compared with control IgG or with GBS-IgG, but does not induce death by necrosis. Because ALS is characterized by the selective loss of motor neurones, we next assessed the differential effect of ALS-IgG on motor neurones or astrocytes. We showed, semiquantitatively, that motor neurones are more susceptible to apoptosis when cultures were treated with ALS-IgG compared with control-IgG. In conclusion, we have demonstrated in primary spinal cord cultures that IgG from patients with ALS induces apoptosis selectively in motor neurones, and that the caspase-3 pathway is involved. This suggests that immunological mechanisms may contribute to the selective loss of motor neurones in ALS.

Apoptosis in amyotrophic lateral sclerosis—what is the evidence?

There is increasing evidence that a programmed mechanism of cell death resembling apoptosis is responsible for motor-neuron degeneration in amyotrophic lateral sclerosis. Our understanding of the cell-death pathway has come from studies of both experimental models and human tissue. Here we examine in detail the in vitro and in vivo evidence for and against apoptosis in amyotrophic lateral sclerosis, looking at morphological changes, caspase activation, alterations in Bcl-2 oncoproteins, involvement of death receptors, expression of apoptosis-related molecules, and the role of the p53 pathway. Finally, we present evidence of potential therapeutic agents that could modulate the apoptotic pathway in amyotrophic lateral sclerosis and slow disease progression.

Spinal cord molecular profiling provides a better understanding of amyotrophic lateral sclerosis pathogenesis

Research efforts in amyotrophic lateral sclerosis (ALS) have not yet provided a comprehensive explanation of the disease pathogenesis, which is emerging as a complex interaction between multiple factors. Gene expression studies traditionally based on single mRNA specie analysis have recently progressed to allow entire transcriptional profiles of affected tissues to be obtained through array-based methods. This experimental approach has significantly improved our understanding of the molecular changes occurring in ALS, although its limitations in the detection of low-abundance transcripts in tissues with a high level of complexity are becoming increasingly recognized. In this paper, experimental findings based on an expression study in post-mortem spinal cord from sporadic ALS individuals will be discussed in light of recently published data using array analysis in an animal model of the disease. Previous expression data obtained using conventional techniques are also compared. Through the analysis of the information arising from ALS post-mortem and animal model tissues studies, we have identified a pattern of molecular events in which factors implicated in the immune response, cytoprotection and growth-differentiation are differentially regulated in a time-dependent way from early to advanced stages of disease progression.

Fas ligand/Fas system in the brain: regulator of immune and apoptotic responses

Apoptosis, also known as programmed cell death, is the major type of cell death involved in normal development, regeneration, proliferation and pathologic degeneration in the central nervous system (CNS). The apoptotic process can be divided further into two pathways depending on the involvement of mitochondria and related biochemical cascades. The internal pathway of apoptosis is initiated by a variety of cytotoxic stimuli and mediated by the release of cytochrome c and subsequent activation of downstream caspases. The external pathway is mainly triggered by ligation of death receptors such as Fas, tumor necrosis factor (TNF)-related apoptosis inducing ligand-R1 (TRAIL-R1), TRAIL-R2 and TNFRp55, and mediated by direct activation of upstream caspases. The Fas-FasL system has been known as a prototypic inducer of extrinsic cell death responsible for cell-mediated cytotoxicity, peripheral immune regulation, immune privilege and "counterattack" of malignant tumor cells against the host immune system. Fas and FasL are expressed in the normal CNS, and expression increases in inflamed and degenerated brains. Like other specialized tissues such as the eye and testis, the Fas-FasL system is thought to be involved in immune suppressed status in the CNS. Expression of Fas and FasL is significantly elevated in a variety of the neurologic disorders, suggesting the possibility that this system may play roles in degenerative and inflammatory responses in the CNS. Therefore, the FasL-Fas system should be considered as a double-edged sword in the CNS: maintaining the immune suppressed status in normal brain and inducing neuronal cell death and inflammation in a variety of neurologic disorders.

Serum anti-Fas antibody levels in amyotrophic lateral sclerosis

In this study, the levels of anti-Fas antibodies were evaluated in patients with amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases. Sera from 25% of patients with sporadic ALS (sALS) and 22% of patients with familial ALS (fALS) contained abnormal levels of anti-Fas antibodies compared with normal controls. Half of patients with Parkinson's disease (PD), but no patients with Alzheimer's disease (AD), had abnormal levels of anti-Fas antibodies. There was no correlation between the antibody levels of patients with ALS and the length or stage of their disease. These data demonstrate that the peripheral immune system is activated as reflected by anti-Fas antibodies in ALS, but this activation is not specific to ALS.

Expression of a functional Fas death receptor by human foetal motoneurons

The expression of the apoptosis inducer Fas (CD95/APO-1) surface receptor by human foetal neurons was investigated in vitro and ex vivo. Immunofluorescence studies of brain and spinal cord cells in primary cultures and of cryosections obtained from 9- and 10-week-old human foetuses, respectively, showed that all Fas-expressing cells were motoneurons (5.3 and 4.2% of the neurons in brain or spinal cord cultures, respectively) on the basis of morphology, reactivity with the monoclonal antibody SMI-32, a mostly motoneuronal marker and acetylcholine esterase expression. Fas was undetectable on the other cell types in culture. The ability of Fas to induce apoptosis of cultured cells from both tissues was determined by using the terminal transferase (TdT)-mediated dUTP nick-end labelling (TUNEL) method combined with the same double-staining procedure. Under basal culture conditions, about 9% of cells, all glial fibrillary acidic protein-expressing astrocytes, were apoptotic. After a 48-h incubation with Fas ligand, mean 28.5% of brain motoneurons and 29.4% of spinal motoneurons underwent apoptosis, with an inhibition by Z-IETD-FMK, a caspase-8 inhibitor. Hence, Fas appears to be functional through a caspase-8-dependent pathway in a subpopulation of human foetal motoneurons.

Sedimentation field flow fractionation purification of immature neural cells from a human tumor neuroblastoma cell line

The use of stem cells for therapeutic applications is now an important objective for the future. Stem cell preparation is difficult and time-consuming depending on the origin of cells. Sedimentation field flow fractionation (SdFFF) is an effective tool for cell separation, respecting integrity and viability. We used the human neuroblastic SH-SY5Y clone of the SK-N-SH cell line as a source of immature neural cells. Our results demonstrated that by using SdFFF cell sorter under strictly defined conditions, and immunological cell characterization, we are now able to provide, in less than 15 min, a sterile, viable, usable and purified immature neural cell fraction without inducting cell differentiation.

In vitro induction of microglial and endothelial cell apoptosis by cerebrospinal fluids from patients with human African trypanosomiasis

In human African trypanosomiasis, trypanosomes first develop in the blood and lymph (Stage 1), then spread to the central nervous system (CNS) (Stage 2). Disruption of the blood-brain barrier of unknown mechanism occurs in Stage 2 disease. The hypothesis that cerebrospinal fluids (CSF) from African trypanosomiasis patients might contain factor(s) able to induce apoptosis in endothelial cells led us to evaluate this effect by two methods, the TdT-mediated dUTP nick end labelling (TUNEL) method and the measurement of soluble nucleosomes released by apoptotic cells in culture supernatant by ELISA. Apoptosis induction by CSF was also studied with microglial cells, the resident macrophages in the brain, which participate in the blood-brain barrier in the perivascular area. In contrast with control CSF, African trypanosomiasis patients' CSF induced apoptosis in both microglial and endothelial cells. The results obtained with the two methods correlated well, and showed that Stage 2 CSF induced apoptosis at higher levels in microglial cells, whereas the disease stage was not decisive for apoptosis induction in endothelial cells. We measured soluble Fas ligand (sFasL) and anti-Fas antibodies levels, two potent inducers of the Fas signalling pathway leading to apoptosis, in CSF from African trypanosomiasis patients and controls. CSF from African trypanosomiasis patients contained sFasL, and anti-Fas antibodies at higher levels than in controls. Stage 2 CSF contained more sFasL than Stage 1 CSF, and anti-Fas antibodies were detected only in Stage 2 CSF. Caspase-8 inhibitor effect and statistical data suggest that other pro-apoptotic factors may be involved in some CSF-induced apoptosis. Apoptosis induction may participate in the pathogenesis during African trypanosomiasis, and the presence of sFasL and anti-Fas antibodies may provide new tools for diagnosis and prognosis of the disease.

Alterations in G(1) to S phase cell-cycle regulators during amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is characterized by progressive degeneration of the motor neurons in the cerebral cortex, brain stem, and spinal cord. However, the mechanisms that regulate the initiation and/or progression of motor neuron loss in this disease remain enigmatic. Cell-cycle proteins and transcriptional regulators such as cyclins, cyclin-associated kinases, the retinoblastoma gene product (pRb), and E2F-1 function during cellular proliferation, differentiation, and cell death pathways. Recent data has implicated increased expression and activation of various cell-cycle proteins in neuronal cell death. We have examined the expression and subcellular distribution of G(1) to S phase cell-cycle regulators in the spinal cord, motor cortex, and sensory cortex from clinically and neuropathologically diagnosed sporadic ALS cases and age-matched controls. Our results indicate hyperphosphorylation of the retinoblastoma protein in motor neurons during ALS, concurrent with increased levels of cyclin D, and redistribution of E2F-1 into the cytoplasm of motor neurons and glia. These data suggest that G(1) to S phase activation occurs during ALS and may participate in molecular mechanisms regulating motor neuron death.