Amyotrophic lateral sclerosis immunoglobulins increase Ca2+ currents in a motoneuron cell line

Passive Transfer of Blood Sera from ALS Patients with Identified Mutations Results in Elevated Motoneuronal Calcium Level and Loss of Motor Neurons in the Spinal Cord of Mice

Introduction: Previously, we demonstrated the degeneration of axon terminals in mice after repeated injections of blood sera from amyotrophic lateral sclerosis (ALS) patients with identified mutations. However, whether a similar treatment affects the cell body of motor neurons (MNs) remained unresolved. Methods: Sera from healthy individuals or ALS patients with a mutation in different ALS-related genes were intraperitoneally injected into ten-week-old male Balb/c mice (n = 3/serum) for two days. Afterward, the perikaryal calcium level was measured using electron microscopy. Furthermore, the optical disector method was used to evaluate the number of lumbar MNs. Results: The cytoplasmic calcium level of the lumbar MNs of the ALS-serum-treated mice, compared to untreated and healthy-serum-treated controls, was significantly elevated. While injections of the healthy serum did not reduce the number of MNs compared to the untreated control group, ALS sera induced a remarkable loss of MNs. Discussion: Similarly to the distant motor axon terminals, the injection of blood sera of ALS patients has a rapid degenerative effect on MNs. Analogously, the magnitude of the evoked changes was specific to the type of mutation; furthermore, the degeneration was most pronounced in the group treated with sera from ALS patients with a mutation in the chromosome 9 open reading frame 72 gene.

Passive Transfer of Sera from ALS Patients with Identified Mutations Evokes an Increased Synaptic Vesicle Number and Elevation of Calcium Levels in Motor Axon Terminals, Similar to Sera from Sporadic Patients

Previously, we demonstrated increased calcium levels and synaptic vesicle densities in the motor axon terminals (MATs) of sporadic amyotrophic lateral sclerosis (ALS) patients. Such alterations could be conferred to mice with an intraperitoneal injection of sera from these patients or with purified immunoglobulin G. Later, we confirmed the presence of similar alterations in the superoxide dismutase 1 G93A transgenic mouse strain model of familial ALS. These consistent observations suggested that calcium plays a central role in the pathomechanism of ALS. This may be further reinforced by completing a similar analytical study of the MATs of ALS patients with identified mutations. However, due to the low yield of muscle biopsy samples containing MATs, and the low incidence of ALS patients with the identified mutations, these examinations are not technically feasible. Alternatively, a passive transfer of sera from ALS patients with known mutations was used, and the MATs of the inoculated mice were tested for alterations in their calcium homeostasis and synaptic activity. Patients with 11 different ALS-related mutations participated in the study. Intraperitoneal injection of sera from these patients on two consecutive days resulted in elevated intracellular calcium levels and increased vesicle densities in the MATs of mice, which is comparable to the effect of the passive transfer from sporadic patients. Our results support the idea that the pathomechanism underlying the identical manifestation of the disease with or without identified mutations is based on a common final pathway, in which increasing calcium levels play a central role.

Time-Course Changes and Role of Autophagy in Primary Spinal Motor Neurons Subjected to Oxygen-Glucose Deprivation: Insights Into Autophagy Changes in a Cellular Model of Spinal Cord Ischemia

Spinal cord ischemia is a severe clinical complication induced by thoracoabdominal aortic surgery, severe trauma, or compression to the spinal column. As one of the most important functional cells in the spinal cord, spinal motor neurons (SMNs) suffer most during the process since they are vulnerable to ischemic injury due to high demands of energy. Previous researches have tried various animal models or organotypic tissue experiments to mimic the process and get to know the pathogenesis and mechanism. However, little work has been performed on the cellular model of spinal cord ischemia, which has been hampered by the inability to obtain a sufficient number of pure primary SMNs for in vitro study. By optimizing the isolation and culture of SMNs, our laboratory has developed an improved culture system of primary SMNs, which allows cellular models and thus mechanism studies. In the present study, by establishing an in vitro model of spinal cord ischemia, we intended to observe the dynamic time-course changes of SMNs and investigate the role of autophagy in SMNs during the process. It was found that oxygen-glucose deprivation (OGD) resulted in destruction of neural networks and decreased cell viability of primary SMNs, and the severity increased with the prolonging of the OGD time. The OGD treatment enhanced autophagy, which reached a peak at 5 h. Further investigation demonstrated that inhibition of autophagy exacerbated the injury, evidencing that autophagy plays a protective role during the process.

IgGs from patients with amyotrophic lateral sclerosis and diabetes target CaVα2δ1 subunits impairing islet cell function and survival

We provide evidence of a mechanistic link between ALS and T2DM. Our data show that a subgroup of ALS-T2DM patients have sera that enhance Ca_V1 channel-mediated Ca²⁺ influx and exaggerate [Ca²⁺]_i. These effects occur because the sera accommodate cytotoxic IgG autoantibodies that immunocapture Ca_Vα₂δ1 subunits. As a consequence, impairments in [Ca²⁺]_i dynamics, mitochondrial function, insulin secretion, and cell viability appear. We could clarify not only the identity of this serum factor but also the molecular mechanisms underlying its effects on the islet cells. Our findings may lay the foundation for a treatment strategy for this complex and severe group of diabetic patients.

Patients with amyotrophic lateral sclerosis (ALS) often show hallmarks of type 2 diabetes mellitus (T2DM). However, the causal link between ALS and T2DM has remained a mystery. We now demonstrate that 60% of ALS patients with T2DM (ALS-T2DM) have sera that exaggerated K⁺-induced increases in cytosolic free Ca²⁺ concentration ([Ca²⁺]_i) in mouse islet cells. The effect was attributed to the presence of pathogenic immunoglobulin Gs (IgGs) in ALS-T2DM sera. The pathogenic IgGs immunocaptured the voltage-dependent Ca²⁺ (Ca_V) channel subunit Ca_Vα₂δ1 in the plasma membrane enhancing Ca_V1 channel-mediated Ca²⁺ influx and [Ca²⁺]_i, resulting in impaired mitochondrial function. Consequently, impairments in [Ca²⁺]_i dynamics, insulin secretion, and cell viability occurred. These data reveal that patients with ALS-T2DM carry cytotoxic ALS-T2DM-IgG autoantibodies that serve as a causal link between ALS and T2DM by immunoattacking Ca_Vα₂δ1 subunits. Our findings may lay the foundation for a pharmacological treatment strategy for patients suffering from a combination of these diseases.

Experimental Motor Neuron Disease Induced in Mice with Long-Term Repeated Intraperitoneal Injections of Serum from ALS Patients

In an earlier study, signs of commencing degeneration of spinal motor neurons were induced in mice with short-term intraperitoneal injections of immunoglobulin G (IgG) taken from patients with amyotrophic lateral sclerosis (ALS). Since in that study, neither weakness nor loss of motor neurons was noted, to test whether the ALS IgG in this paradigm has the potential to evoke relentless degeneration of motor neurons, treatment with repeated injections over a longer period was carried out. Mice were systematically injected intraperitoneally with serum taken from ALS patients over a 75-day period. At selected time points, the isometric force of the limbs, number of spinal motor neurons and their intracellular calcium levels were determined. Furthermore, markers of glial activation and the motoneuronal uptake of human IgG were monitored. During this period, gliosis and progressive motoneuronal degeneration developed, which led to gradual loss of spinal motor neurons, more than 40% at day 21, along with decreasing muscle strength in the limbs. The inclusion-like accumulation of IgG appeared in the perikarya with the increase of intracellular calcium in the cell bodies and motor nerve terminals. Our results demonstrate that ALS serum can transfer motor neuron disease to mice.

Calcium in the pathomechanism of amyotrophic lateral sclerosis - Taking center stage?

Amyotrophic lateral sclerosis is an incurable, relentlessly progressive disease primarily affecting motor neurons. The cause of the disease, except for the mutations identified in a small fraction of patients, is unknown. The major mechanisms contributing to the degeneration of motor neurons have already been disclosed and characterized, including excitotoxicity, oxidative stress, mitochondrial dysfunction, and immune/inflammatory processes. During the progression of the disease these toxic processes are not discrete, but each facilitates the deleterious effect of the other. However, due to their common reciprocal calcium dependence, calcium ions may act as a common denominator and through a positive feedback loop may combine the individual pathological processes into a unified escalating mechanism of neuronal destruction. This mini-review provides an overview of the mutual calcium dependence of the major toxic mechanisms associated with amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis-immunoglobulins selectively interact with neuromuscular junctions expressing P/Q-type calcium channels

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by a gradual loss of motoneurons. The majority of ALS cases are associated with a sporadic form whose etiology is unknown. Several pieces of evidence favor autoimmunity as a potential contributor to sporadic ALS pathology. To gain understanding concerning possible antigens interacting with IgGs from sporadic ALS patients (ALS-IgGs), we studied immunoreactivity against neuromuscular junction (NMJ), spinal cord and cerebellum of mice with and without the Ca(V) 2.1 pore-forming subunit of the P/Q-type voltage-gated calcium (Ca(2+)) channel. ALS-IgGs showed a strong reactivity against NMJs of wild-type diaphragms. ALS-IgGs also increased muscle miniature end-plate potential frequency, suggesting a functional role for ALS-IgGs on synaptic signaling. In support, in mice lacking the Ca(V) 2.1 subunit ALS-IgGs showed significantly reduced NMJ immunoreactivity and did not alter spontaneous acetylcholine release. This difference in reactivity was absent when comparing N-type Ca(2+) channel wild-type or null mice. These results are particularly relevant because motoneurons are known to be early pathogenic targets in ALS. Our findings add further evidence supporting autoimmunity as one of the possible mechanisms contributing to ALS pathology. They also suggest that serum autoantibodies in a subset of ALS patients would interact with NMJ proteins down-regulated when P/Q-type channels are absent.

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.

Calpain inhibition protected spinal cord motoneurons against 1-methyl-4-phenylpyridinium ion and rotenone

Parkinson's disease (PD), characterized by selective midbrain nigrostriatal dopaminergic degeneration, is consistently associated with moderate systemic mitochondrial dysfunction. Downstream degeneration of spinal cord has also been suggested in PD, although the mechanisms have not been much investigated. In the present study, two mitochondrial toxicants, 1-methyl-4-phenylpyridinium ion (MPP(+)) and rotenone were tested in ventral spinal cord (VSC 4.1) motoneuronal cells. Cell death was assessed by morphological and biochemical means to discern a lower apoptosis-inducing concentration and lethal concentration of 50% cell death (LC(50)), which were subsequently compared in further cytoprotection experiments. Mitochondrial toxicants dose-dependently induced increase in intracellular free Ca(2+) level, which was conducive for increased expression and activities of Ca(2+)-activated neutral protease calpain and downstream caspase-3. Thus, mitochondrial damage triggered apoptotic mechanisms in spinal cord motoneurons. Inhibition of calpain by calpeptin significantly attenuated damaging effects of MPP(+) and rotenone on motoneurons, especially at low apoptosis-inducing concentrations of toxicants and partly at their LC(50), as demonstrated by absence of DNA ladder formation and decrease in terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells. Cytoprotection by calpeptin was observed with marked decreases in Bax: Bcl-2 ratio and activities of calpain and caspase-3, which affirmed the role of mitochondrial dysfunction and involvement of intrinsic pathway in mediation of apoptosis. These findings strongly suggested that parkinsonian toxicants MPP(+) and rotenone at low doses induced cascade of cell-damaging effects in spinal cord motoneurons, thus, highlighting the possibility of induction of apoptotic mechanisms in these cells, when subjected to mitochondrial stress. Cytoprotection rendered by calpeptin further validated the involvement of calpain in apoptosis and suggested calpain inhibition as a potential neuroprotective strategy.

Intrinsic properties of lumbar motor neurones in the adult G127insTGGG superoxide dismutase-1 mutant mouse in vivo: evidence for increased persistent inward currents

AIM

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by a preferential loss of motor neurones. Previous publications using in vitro neonatal preparations suggest an increased excitability of motor neurones in various superoxide dismutase-1 (SOD1) mutant mice models of ALS which may contribute to excitotoxicity of the motor neurones.

METHODS

Using intracellular recording, we tested this hypothesis in vivo in the adult presymptomatic G127insTGGG (G127X) SOD1 mutant mouse model of ALS.

RESULTS

At resting membrane potentials the basic intrinsic properties of lumbar motor neurones in the adult presymptomatic G127X mutant are not significantly different from those of wild type. However, at more depolarized membrane potentials, motor neurones in the G127X SOD1 mutants can sustain higher frequency firing, showing less spike frequency adaption (SFA) and with persistent inward currents (PICs) being activated at lower firing frequencies and being more pronounced.

CONCLUSION

We demonstrated that, in vivo, at resting membrane potential, spinal motor neurones of the adult G127X mice do not show an increased excitability. However, when depolarized they show evidence of an increased PIC and less SFA which may contribute to excitotoxicity of these neurones as the disease progresses.

Golgi apparatus and neurodegenerative diseases

Neurodegenerative disorders are typically characterized by progressive and extensive neuronal loss in specific populations of neurons and brain areas which lead to the observed clinical manifestations. Despite the recent advances in molecular neuroscience, the subcellular bases such as Golgi apparatus (GA) for most neurodegenerative diseases are poorly understood. This review gives a brief overview of the contribution of the neuronal GA in the pathogeneses of neurodegeneration, summarizes what is known of the GA machinery in these diseases, and present the relationship between GA fragmentation and the aggregation and accumulation of misfolded or aberrant proteins including mutant SOD1, a-synuclein, tau, which is considered to be a key event in the pathogenic process, and perturbating in calcium homeostasis, regulation of hormones, lipid metabolism are also linkage to the function of the GA thought to underlie neurodegeneration. Although these precise diseases mechanisms remain to be clarified, more research is needed to better understand how GA function for it and to enable physicians to use this knowledge for the benefit of the patients.

Axotomy induces contrasting changes in calcium and calcium-binding proteins in oculomotor and hypoglossal nuclei of Balb/c mice

Motor neurons with different susceptibility to degeneration have been identified in amyotrophic lateral sclerosis (ALS). Increase of intracellular calcium has been proposed as a mediator, amplifying the damage through a positive feedback of the known pathological processes. Accordingly, the potential of motor neurons to limit calcium increases during injury might be proportional to their viability. A basic mechanism of reducing calcium amplitudes depends on the calcium-buffering capacity, determined by the calcium-binding protein content. In this study, oculomotor and hypoglossal neurons, prototypes of resistant and vulnerable motor neurons in ALS were examined in axotomy experiments. Total calcium-, parvalbumin-, and calbindin-D28k levels of motor neurons of adult mice were characterized by electron microscopic histochemistry and light microscopic immunostaining. In hypoglossal neurons, compared with oculomotor neurons, larger and more enduring increases of calcium were detected. The perikarya of hypoglossal neurons remained immunonegative for both parvalbumin and calbindin-D28k. Qualitatively, no major cell loss was noted after axotomy, but a decreased neuronal marker staining at days 1-14 suggested a reversible injury of hypoglossal neurons. Oculomotor neurons were not stained for calbindin-D28k but stained for parvalbumin in control conditions, staining which increased at postoperative days 7-14 before returning to baseline. Neuronal marker staining did not change in these cells during the observed period. The higher level of parvalbumin in resistant motor neurons and their ability to up-regulate parvalbumin after injury, paralleled by a smaller increase of intracellular calcium suggest that parvalbumin may have a protective effect in these cells.

Calcium signaling pathways mediating synaptic potentiation triggered by amyotrophic lateral sclerosis IgG in motor nerve terminals

Sporadic amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects particularly motoneurons. Several pieces of evidence suggested the involvement of autoimmune mechanisms mediated by antibodies in ALS. However, the significance of those antibodies in the disease and the underlying mechanisms are unknown. Here we showed that IgG purified from a group of sporadic ALS patients, but not familial ALS patients, specifically interact with the presynaptic membrane of motoneurons through an antigen-antibody interaction and modulated synaptic transmission. Immunoreactivity against nerve terminals showed strong correlation with synaptic modulation ability. In addition, several controls have ruled out the possibility for this synaptic modulation to be mediated through proteases or nonspecific effects. Effective IgG potentiated both spontaneous and asynchronous transmitter release. Application of pharmacological inhibitors suggested that activation of this increased release required a nonconstitutive Ca2+ influx through N-type (Cav2.2) channels and phospholipase C activity and that activation of IP3 and ryanodine receptors were necessary to both activate and sustain the increased release. Consistent with the notion that ALS is heterogeneous disorder, our results reveal that, in approximately 50% of ALS patients, motor nerve terminals constitutes a target for autoimmune response.

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.

Differential expression of voltage-activated calcium channels in III and XII motoneurones during development in the rat

To further our understanding of the role that voltage-activated Ca2+ channels play in the development, physiology and pathophysiology of motoneurones (MNs), we used whole-cell patch-clamp recording to compare voltage-activated Ca2+ currents in oculomotor (III) and hypoglossal (XII) MNs of neonatal [postnatal day (P)1-5] and juvenile (P14-19) rats. In contrast to III MNs that innervate extraocular muscles, XII MNs that innervate tongue muscles mature more rapidly, fire bursts of low frequency action potentials and are vulnerable to degeneration in amyotrophic lateral sclerosis. In neonates, low voltage-activated (LVA) Ca2+ current densities are similar in XII and III MNs but high voltage-activated (HVA) Ca2+ current densities are twofold higher in XII MNs. The HVA Ca2+ channel antagonists (nimodipine and nifedipine for L-type, omega-agatoxin-TK for P/Q-type and omega-conotoxin-GVIA for N-type) revealed that, while N- and P/Q-type HVA Ca2+ channels are present in both MN pools, a 3.5-fold greater P/Q-type Ca2+ current in XII MNs accounts for their greater HVA Ca2+ currents. Developmentally, LVA and HVA Ca2+ current densities decrease in III MNs but remain unchanged in XII MNs. Thus, the differences between these MN pools increase developmentally so that, in juveniles, the LVA Ca2+ current density is twofold greater and the HVA Ca2+ current density is threefold greater in XII compared with III MNs. We propose that this differential expression of LVA and HVA Ca2+ channels in XII and III MNs during development contributes to their distinct physiology and may also be a factor contributing to the greater susceptibility of XII MNs to degeneration as seen in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis patient IgG alters voltage dependence of Ca2+ channels in dissociated rat motoneurons

Previous studies on sporadic amyotrophic lateral sclerosis (SALS) have detected IgG within motoneurons of patients and these IgGs have been shown to alter voltage dependent calcium channel activity in various cell types. The current study investigates whether IgG from categorized SALS patients alter voltage dependent calcium currents in rat motoneurons in culture. Patients were categorized based on onset and progression pattern. IgG yields were 38% higher in SALS patients compared to control subjects. Incubation with 1 mg/ml IgG from SALS patients did not cause visible toxicity, alter input resistance, capacitance or the maximal calcium conductance in rat motoneurons when compared to motoneurons incubated with control IgG. However, the activation curve of calcium current was shifted to the left in motoneurons treated with SALS IgG compared to control IgG.

Efficient three-drug cocktail for disease induced by mutant superoxide dismutase

There is currently no effective pharmacological treatment for amyotrophic lateral sclerosis (ALS). Because evidence suggests that multiple pathways may contribute to ALS pathogenesis, we tested in a mouse model of ALS (SOD1(G37R) mice) a combination approach consisting of three drugs for distinct targets in the complex pathway to neuronal death: minocycline, an antimicrobial agent that inhibits microglial activation, riluzole, a glutamate antagonist, and nimodipine, a voltage-gated calcium channel blocker. The efficacy of this three-drug cocktail was remarkable when administered in the diet from late presymptomatic stage (8-9 months). It delayed the onset of disease, slowed the loss of muscle strength, and increased the average longevity of SOD1(G37R) mice by 6 weeks. The protective effect of the treatment was corroborated by the reduced immunodetection signals for markers of gliosis and neurodegeneration in the spinal cord of SOD1(G37R) mice. These results indicate that such three-drug combination may represent an effective strategy for ALS treatment.

Altered calcium in motoneurons by IgG from human motoneuron diseases

OBJECTIVES

The effect of IgG from patients with multifocal motor neuropathy (MMN) on the content and distribution of calcium in spinal motoneurons was compared with the effect of IgG from patients with sporadic amyotrophic lateral sclerosis (SALS) and IgG from normal individuals.

MATERIAL AND METHODS

Different purified IgG samples were injected intraperitoneally in mice. Then, the animals were subjected to histochemical techniques to visualize calcium in electron microscopic sections.

RESULTS

Quantitative morphometric analysis verified that IgG from MMN decreased the vesicular and axoplasmic calcium content in the axon terminals at the neuromuscular junctions and had no influence on the perikaryon. In contrast to this, IgG from patients with SALS increased the intracellular calcium both in the axon terminal and in the perikaryon. IgG from normal individuals exerted no effect. Elevated intracellular calcium may contribute to motoneuron degeneration. The lack of such effect with MMN immunoglobulins helps to explain the relative sparing of motoneurons in the disease.

Parvalbumin overexpression alters immune-mediated increases in intracellular calcium, and delays disease onset in a transgenic model of familial amyotrophic lateral sclerosis

Intracellular calcium is increased in vulnerable spinal motoneurons in immune-mediated as well as transgenic models of amyotrophic lateral sclerosis (ALS). To determine whether intracellular calcium levels are influenced by the calcium-binding protein parvalbumin, we developed transgenic mice overexpressing parvalbumin in spinal motoneurons. ALS immunoglobulins increased intracellular calcium and spontaneous transmitter release at motoneuron terminals in control animals, but not in parvalbumin overexpressing transgenic mice. Parvalbumin transgenic mice interbred with mutant SOD1 (mSOD1) transgenic mice, an animal model of familial ALS, had significantly reduced motoneuron loss, and had delayed disease onset (17%) and prolonged survival (11%) when compared with mice with only the mSOD1 transgene. These results affirm the importance of the calcium binding protein parvalbumin in altering calcium homeostasis in motoneurons. The increased motoneuron parvalbumin can significantly attenuate the immune-mediated increases in calcium and to a lesser extent compensate for the mSOD1-mediated 'toxic-gain-of-function' in transgenic mice.

Cyclophosphamide attenuates the degenerative changes induced by CSF from patients with amyotrophic lateral sclerosis in the neonatal rat spinal cord

Our earlier studies have shown that cerebrospinal fluid (CSF) of patients with amyotrophic lateral sclerosis (ALS), when intrathecally injected into the neonatal rats, produces an aberrant phosphorylation of neurofilaments (NF) in the ventral horn neurons and reactive astrogliosis in the spinal cord. We wanted to investigate the effect of cyclophosphamide in the spinal cords of neonatal rats exposed to ALS-CSF. A single dose (5 microg in 5 microl saline) of cyclophosphamide was injected, 24 h after the administration of CSF samples from ALS and non-ALS neurological patients into the spinal subarachnoid space of 3-day-old rat pups. Rats were sacrificed after a period of 24 h, and stained with antibodies against the phosphorylated NF (SMI-31 antibody) and glial fibrillary acidic protein (GFAP). Cyclophosphamide treatment resulted in a 50% decrease in the number of SMI-31 stained neuronal soma in ventral horns of spinal cords of ALS-CSF exposed rats. This was accompanied by a decrease in the number of GFAP immunoreactive astrocytes. Furthermore, lactate dehydrogenase (LDH) activity was also decreased significantly, following cyclophosphamide treatment. These results suggest that cyclophosphamide could exert a neuroprotective effect against the neurotoxic action of factor(s) present in the ALS-CSF.

Abnormal intracellular ca(2+)homeostasis and disease

A whole range of cell functions are regulated by the free cytosolic Ca(2+)concentration. Activator Ca(2+)from the extracellular space enters the cell through various types of Ca(2+)channels and sometimes the Na(+)/Ca(2+)-exchanger, and is actively extruded from the cell by Ca(2+)pumps and Na(+)/Ca(2+)-exchangers. Activator Ca(2+)can also be released from internal Ca(2+)stores through inositol trisphosphate or ryanodine receptors and is taken up into these organelles by means of Ca(2+)pumps. The resulting Ca(2+)signal is highly organized in space, frequency and amplitude because the localization and the integrated free cytosolic Ca(2+)concentration over time contain specific information. Mutations or functional abnormalities in the various Ca(2+)transporters, which in vitro seem to induce trivial functional alterations, therefore, often lead to a plethora of diseases. Skeletal-muscle pathology can be caused by mutations in ryanodine receptors (malignant hyperthermia, porcine stress syndrome, central-core disease), dihydropyridine receptors (familial hypokalemic periodic paralysis, malignant hyperthermia, muscular dysgenesis) or Ca(2+)pumps (Brody disease). Ca(2+)-pump mutations in cutaneous epidermal keratinocytes and cochlear hair cells lead to, skin diseases (Darier and Hailey-Hailey) and hearing/vestibular problems respectively. Mutated Ca(2+)channels in the photoreceptor plasma membrane cause vision problems. Hemiplegic migraine, spinocerebellar ataxia type-6, one form of episodic ataxia and some forms of epilepsy can be due to mutations in plasma-membrane Ca(2+)channels, while antibodies against these channels play a pathogenic role in all patients with the Lambert-Eaton myasthenic syndrome and may be of significance in sporadic amyotrophic lateral sclerosis. Brain inositol trisphosphate receptors have been hypothesized to contribute to the pathology in opisthotonos mice, manic-depressive illness and perhaps Alzheimer's disease. Various abnormalities in Ca(2+)-handling proteins have been described in heart during aging, hypertrophy, heart failure and during treatment with immunosuppressive drugs and in diabetes mellitus. In some instances, disease-causing mutations or abnormalities provide us with new insights into the cell biology of the various Ca(2+)transporters.

Amyotrophic lateral sclerosis and occupational exposure to electromagnetic fields

In an hypothesis-generating case-control study of amyotrophic lateral sclerosis, lifetime occupational histories were obtained. The patients (n = 28) were clinic based. The occupational exposure of interest in this report is electromagnetic fields (EMFs). This is the first and so far the only exposure analyzed in this study. Occupational exposure up to 2 years prior to estimated disease symptom onset was used for construction of exposure indices for cases. Controls (n = 32) were blood and nonblood relatives of cases. Occupational exposure for controls was through the same age as exposure for the corresponding cases. Twenty (71%) cases and 28 (88%) controls had at least 20 years of work experience covering the exposure period. The occupational history and task data were used to classify blindly each occupation for each subject as having high, medium/high, medium, medium/low, or low EMF exposure, based primarily on data from an earlier and unrelated study designed to obtain occupational EMF exposure information on workers in "electrical" and "nonelectrical" jobs. By using the length of time each subject spent in each occupation through the exposure period, two indices of exposure were constructed: total occupational exposure (E1) and average occupational exposure (E2). For cases and controls with at least 20 years of work experience, the odds ratio (OR) for exposure at the 75th percentile of the E1 case exposure data relative to minimum exposure was 7.5 (P < 0.02; 95% CI, 1.4-38.1) and the corresponding OR for E2 was 5.5 (P < 0.02; 95% CI, 1.3-22.5). For all cases and controls, the ORs were 2.5 (P < 0.1; 95% CI, 0.9-8.1) for E1 and 2.3 (P = 0.12; 95% CI, 0.8-6.6) for E2. This study should be considered an hypothesis-generating study. Larger studies, using incident cases and improved exposure assessment, should be undertaken.

Ultrastructural evidence of calcium involvement in experimental autoimmune gray matter disease

Experimental studies have suggested that increased calcium and inappropriate calcium handling by motoneurons might have a significant role in motoneuron degeneration. To further define the involvement of calcium in motoneuron loss we used the oxalate-pyroantimonate technique for calcium fixation and monitored the ultrastructural distribution of calcium in spinal motoneurons in experimental autoimmune gray matter disease (EAGMD). In cervical and hypoglossal motoneurons from animals with relatively preserved upper extremity and bulbar function, increased calcium precipitates were present in the cytoplasm as well as in mitochondria, endoplasmic reticulum and Golgi complex without significant morphologic alterations. In surviving lumbar motoneurons of animals with hindlimb paralysis, however, there was massive morphological destruction of intracellular organelles but no significant accumulation of calcium precipitates. These findings suggest that altered calcium homeostasis is involved in motoneuron immune-mediated injury with increased calcium precipitates early in the disease process and decreased to absent calcium precipitates later in the pathogenesis of motoneuron injury.

Characterization of Ca(2+)-channels responsible for K(+)-evoked [(3)H]noradrenaline release from rat brain cortex synaptosomes and their response to amyotrophic lateral sclerosis IgGs

The contribution of the different Ca(2+)-channel subtypes to the K(+)-evoked [(3)H]noradrenaline release from rat cerebral cortex synaptosomes has been investigated. In the same experimental model, it was also verified whether the calcium-mediated neurotransmitter release is influenced by IgGs purified from sera of seven patients affected by sporadic amyotrophic lateral sclerosis. Synaptosome treatment with 3.0 microM nifedipine or 2.0 microM calciseptine, which block L-type channels, slightly decreased [(3)H]noradrenaline release, the reduction being 7 and 13% of the control values, respectively. The blockade of N-type Ca(2+)-channels with omega-conotoxin-GVIA (0.001-1.0 microM) induced a concentration-dependent reduction of the neurotransmitter release, with maximum effect of 34%. omega-Agatoxin-IVA failed to significantly affect the studied release, which was instead markedly reduced by omega-conotoxin-MVIIC. After the blockade of N-type channels with maximal concentrations of omega-conotoxin-GVIA, 3.0 microM omega-conotoxin-MVIIC reduced the release by 58%. Synaptosome treatment with amyotrophic lateral sclerosis IgGs enhanced the K(+)-evoked [(3)H]noradrenaline release, which was mostly mediated by P/Q- and N-type Ca(2+)-channels. The increase induced by pathologic IgGs (0.2 mg/ml) ranged from 11 to 62% for the different patients, and it was concentration-dependent. The basal release was instead unaffected by IgG treatment. The results of the present study suggest that the K(+)-evoked [(3)H]noradrenaline release from brain cortex synaptosomes is mainly mediated by activation of P/Q- and N-type Ca(2+)-channels. Autoantibodies present in the sera of patients affected by sporadic amyotrophic lateral sclerosis may interact with these channels by producing an increased calcium influx, with consequent enhancement of the neurotransmitter release. Preliminary results of the present study have been published in abstract form (Martire et al., 1997, Pharmacol. Res. 35:9).

T cell receptor BV gene rearrangements in the spinal cords and cerebrospinal fluid of patients with amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a fatal disorder whose etiology and pathogenesis remain unknown. Recent studies, however, have demonstrated the presence of inflammatory infiltrates within ALS spinal cord and suggested the possibility of an immune-mediated process in motor neuron degeneration. We have analyzed the diversity of T-cells in the spinal cord in ALS. Reverse transcriptase polymerase chain reaction (RT-PCR) with variable (V) region sequence specific oligonucleotide primers was used to amplify T-cell receptor (TCR)BV transcripts from spinal cords obtained at autopsy from patients with ALS, patients who died without inflammatory disease of the central nervous system, brains from patients with ALS, and brains from patients who died with inflammatory CNS disease. Sequencing was then performed on the amplified transcripts. An overall increase in the level of TCRBV 2 transcripts was detected in ALS specimens when compared to controls. This result was independent of the HLA genotype of the individual. Furthermore, enrichment of TCRBV2-positive T cells could be demonstrated in cerebrospinal fluid derived from patients with ALS, using PCR analysis and a T cell stimulation assay with toxic shock syndrome toxin-1 (TSST-1), a Vbeta2-specific superantigen. Our results suggest that an immunological process involving the specific expansion of Vbeta2 TCR-positive T-cells may be important in the pathogenesis of ALS.

Ion channels in presynaptic nerve terminals and control of transmitter release

The primary function of the presynaptic nerve terminal is to release transmitter quanta and thus activate the postsynaptic target cell. In almost every step leading to the release of transmitter quanta, there is a substantial involvement of ion channels. In this review, the multitude of ion channels in the presynaptic terminal are surveyed. There are at least 12 different major categories of ion channels representing several tens of different ion channel types; the number of different ion channel molecules at presynaptic nerve terminals is many hundreds. We describe the different ion channel molecules at the surface membrane and inside the nerve terminal in the context of their possible role in the process of transmitter release. Frequently, a number of different ion channel molecules, with the same basic function, are present at the same nerve terminal. This is especially evident in the cases of calcium channels and potassium channels. This abundance of ion channels allows for a physiological and pharmacological fine tuning of the process of transmitter release and thus of synaptic transmission.

The lipid peroxidation product 4-hydroxynonenal impairs glutamate and glucose transport and choline acetyltransferase activity in NSC-19 motor neuron cells

Both oxidative stress and excitotoxicity are implicated in the pathogenesis of a number of neurodegenerative disorders, such as amyotrophic lateral sclerosis. We previously reported increased modification of proteins by 4-hydroxynonenal (HNE), a product of membrane lipid peroxidation, in the spinal cords of patients with amyotrophic lateral sclerosis relative to controls. In the current study, we examined the functional consequences of protein modification by HNE in a cell line with a motor neuron phenotype, NSC-19. Treatment of NSC-19 cells with FeSO4, which catalyzes lipid peroxidation, or HNE induced concentration-dependent decreases in glucose and glutamate transport. Vitamin E and propyl gallate blocked the impairment of glucose and glutamate transport caused by FeSO4 in these cells, but not that caused by HNE, whereas glutathione blocked the effects of FeSO4 as well as HNE. Both FeSO4 and HNE caused an increase in the number of apoptotic nuclei in NSC-19 cultures, but this occurred subsequent to the impairment of glucose and glutamate transport. Reductions in choline acetyltransferase activity were also observed in FeSO4- or HNE-treated NSC-19 cells before induction of apoptosis. Our results suggest that, prior to cell death, oxidative stress and HNE down-regulate cholinergic markers and impair glucose and glutamate transport in motor neurons, the latter of which may lead to excitotoxic degeneration of the cells.

Single-cell RT-PCR and functional characterization of Ca2+ channels in motoneurons of the rat facial nucleus

Voltage-dependent Ca2+ channels are a major pathway for Ca2+ entry in neurons. We have studied the electrophysiological, pharmacological, and molecular properties of voltage-gated Ca2+ channels in motoneurons of the rat facial nucleus in slices of the brainstem. Most facial motoneurons express both low voltage-activated (LVA) and high voltage-activated (HVA) Ca2+ channel currents. The HVA current is composed of a number of pharmacologically separable components, including 30% of N-type and approximately 5% of L-type. Despite the dominating role of P-type Ca2+ channels in transmitter release at facial motoneuron terminals described in previous studies, these channels were not present in the cell body. Remarkably, most of the HVA current was carried through a new type of Ca2+ channel that is resistant to toxin and dihydropyridine block but distinct from the R-type currents described in other neurons. Using reverse transcription followed by PCR amplification (RT-PCR) with a powerful set of primers designed to amplify all HVA subtypes of the alpha1-subunit, we identified a highly heterogeneous expression pattern of Ca2+ channel alpha1-subunit mRNA in individual neurons consistent with the Ca2+ current components found in the cell bodies and axon terminals. We detected mRNA for alpha1A in 86% of neurons, alpha1B in 59%, alpha1C in 18%, alpha1D in 18%, and alpha1E in 59%. Either alpha1A or alpha1B mRNAs (or both) were present in all neurons, together with various other alpha1-subunit mRNAs. The most frequently occurring combination was alpha1A with alpha1B and alpha1E. Taken together, these results demonstrate that the Ca2+ channel pattern found in facial motoneurons is highly distinct from that found in other brainstem motoneurons.

Amyotrophic lateral sclerosis: serum factors enhance spontaneous and evoked transmitter release at the neuromuscular junction

Sera from 30 patients with sporadic amyotrophic lateral sclerosis (ALS) were tested to determine their effects at the neuromuscular junction. Spontaneous transmitter release was significantly increased, as evidenced by a 151% increase in MEPP frequency, by sera from 16 ALS patients. In addition, 16 patients' sera elevated EEP quantal content by an average of 89%. Eleven sera produced both effects. There was no consistent change in MEPP amplitude or time course, indicating the absence of a humoral effect on postjunctional ACh receptors or endplate membrane function. These results suggest that a portion of the sporadic ALS patient population possess serum factors that can alter presynaptic function of the motor nerve terminal. Evidence from the present experiments indicates that alterations at the neuromuscular junction are a result of a combination of increased Ca2+ influx into the cell and an independent increase in intracellular calcium concentration.

Lack of effect of Miller Fisher sera/plasmas on transmitter release from PC12 cells

IgG antibodies to GQ1b ganglioside are found in > 90% of patients with the Miller Fisher Syndrome (MFS). MFS sera or IgG preparations have marked effects on neurotransmitter release at the neuromuscular junction, but their mode(s) of action remain unclear. To establish a cell-based system for investigating the mechanism of action of MFS serum preparations, we looked at neurotransmitter release from three cell lines. We failed to demonstrate substantial 14C-acetylcholine release from two motor-neuronal cell lines, VSC4.1 and NSC19, and therefore studied 3H-noradrenaline release from NGF-differentiated PC12 cells, a neural-crest derived catecholaminergic cell line. K(+)-induced release was inhibited by botulinum toxin and basal release was enhanced by alpha-latrotoxin, resembling that at the neuromuscular junction, although K(+)-induced release was dependent on L-type rather than P/Q-type calcium channels. The cells expressed polysialylated gangliosides on the cell surface. Incubation in heat-inactivated or untreated MFS preparations did not, however, affect basal or K(+)-induced release. Thus the PC12 cells do not appear to be sensitive to the effects of serum antibodies from MFS patients.

Sera from amyotrophic lateral sclerosis patients reduce high-voltage activated Ca2+ currents in mice dorsal root ganglion neurons

This study investigated the effects of sera from amyotrophic lateral sclerosis (ALS) patients on high voltage activated (HVA) Ca2+ current in mice dorsal root ganglion (DRG) cells using whole-cell voltage-clamp method. Mice were injected with sera from healthy adults, from patients with other neurological diseases, and from patients with the sporadic form of ALS, for a period of 3 days. Sera from five of six ALS patients reduced HVA Ca2+ current amplitude. The peak Ca2+ current was significantly reduced by ALS sera while the sera from healthy adults and patients with other diseases did not alter Ca2+ current. The inactivation kinetics was altered by ALS sera, and the half-inactivation voltage shifted to more negative potential in ALS group. These results suggest that sporadic ALS serum factors may exert interactions with the HVA Ca2+ channel in DRG cells to reduce the Ca2+ current.

Immunoglobulins from motoneurone disease patients enhance glutamate release from rat hippocampal neurones in culture

1. The whole-cell configuration of the patch-clamp technique was used to study the effects of immunoglobulins (IgGs) from patients affected by amyotrophic lateral sclerosis (ALS) on spontaneous glutamatergic currents in rat hippocampal cells in culture. 2. Focal application of ALS IgGs (100 micrograms ml-1) to hippocampal cells induced a rise in frequency but not in amplitude of spontaneous excitatory postsynaptic currents (SEPSC) which outlasted the period of IgG application. The mean frequency ratio (ALS over control) was 3.2 +/- 0.6 (n = 19). No changes in frequency or amplitude of SEPSCs were observed after treatment with IgGs obtained from healthy donors (n = 5) or from patients with Alzheimer's disease (n = 4). 3. ALS IgGs also increased the frequency (by a factor of 2.0 +/- 0.3) but not the amplitude of miniature excitatory postsynaptic currents (mEPSC) recorded in the presence of TTX (n = 19). A rise in frequency of mEPSC was also seen in cells superfused with a calcium-free solution (n = 4). 4. In the presence of TTX, ALS IgGs did not modify the amplitude or the shape of currents evoked by AMPA (100 microM), recorded at a holding potential of -50 mV. 5. It is concluded that ALS IgGs enhance both SEPSCs and mEPSCs through a presynaptic type of action. The excessive release of glutamate from nerve endings may be the cause of motoneurone death in ALS patients.

Expression of a Cu,Zn superoxide dismutase typical of familial amyotrophic lateral sclerosis induces mitochondrial alteration and increase of cytosolic Ca2+ concentration in transfected neuroblastoma SH-SY5Y cells

We have set up a model system for familial amyotrophic lateral sclerosis (FALS) by transfecting human neuroblastoma cell line SH-SY5Y with plasmids directing constitutive expression of either wild-type human Cu,Zn superoxide dismutase (Cu,ZnSOD) or a mutant of this enzyme (G93A) associated with FALS. We have tested mitochondrial function and determined cytosolic Ca2+ concentration in control cells (untransfected) and in cells expressing either wild-type Cu,ZnSOD or G93A. We report that G93A induces a significant loss of mitochondrial membrane potential, an increased sensitivity toward valinomycin and a parallel increase in cytosolic Ca2+ concentration. The above phenomena are not related to total Cu,ZnSOD content and activity in the cell.

Differential localization of voltage-dependent calcium channel alpha1 subunits at the human and rat neuromuscular junction

Neurotransmitter release is regulated by voltage-dependent calcium channels (VDCCs) at synapses throughout the nervous system. At the neuromuscular junction (NMJ) electrophysiological and pharmacological studies have identified a major role for P- and/or Q-type VDCCs in controlling acetylcholine release from the nerve terminal. Additional studies have suggested that N-type channels may be involved in neuromuscular transmission. VDCCs consist of pore-forming alpha1 and regulatory beta subunits. In this report, using fluorescence immunocytochemistry, we provide evidence that immunoreactivity to alpha1A, alpha1B, and alpha1E subunits is present at both rat and human adult NMJs. Using control and denervated rat preparations, we have been able to establish that the subunit thought to correspond to P/Q-type channels, alpha1A, is localized presynaptically in discrete puncta that may represent motor nerve terminals. We also demonstrate for the first time that alpha1A and alpha1B (which corresponds to N-type channels) may be localized in axon-associated Schwann cells and, further, that the alpha1B subunit may be present in perisynaptic Schwann cells. In addition, the alpha1E subunit (which may correspond to R/T-type channels) seems to be localized postsynaptically in the muscle fiber membrane and concentrated at the NMJ. The possibility that all three VDCCs at the NMJ are potential targets for circulating autoantibodies in amyotrophic lateral sclerosis is discussed.

Amyotrophic lateral sclerosis immunoglobulins increase intracellular calcium in a motoneuron cell line

A hybrid motoneuron cell line (VSC4.1) was used as a model system to study the relationship between alterations in intracellular calcium and subsequent cell death induced by immunoglobulin fractions purified from sera of patients with ALS. Using fluo-3 fluorescence imaging, immunoglobulins from 8 of 10 patients with ALS were found to induce transient increases in intracellular calcium ([Ca2+]i) in differentiated VSC4.1 cells. These transient [Ca2+]i increases required extracellular calcium entry through voltage-gated calcium channels sensitive to synthetic FTX and to high concentrations (>1 microM) of omega-agatoxin IVa. The incidence of transient [Ca2+]i increases induced by ALS immunoglobulins correlated with the extent of cytotoxicity induced by the same ALS immunoglobulins in parallel cultures of VSC4.1 cells. Furthermore, manipulations which blocked transient [Ca2+]i increases (addition of synthetic FTX or omega-agatoxin IVa) also inhibited the cytotoxic effects of ALS immunoglobulins. No transient calcium increases were observed in VSC4.1 cells following addition of immunoglobulins from 7 neurologic disease control patients. However, transient [Ca2+]i increases were observed following addition of immunoglobulins from 4 of 5 patients with myasthenia gravis (MG). The [Ca2+]i changes induced by MG immunoglobulins were not blocked by s-FTX, suggesting that they result from a different mechanism than those induced by ALS immunoglobulins. These results suggest that immunoglobulins from patients with ALS can induce transient increases in intracellular calcium in a motoneuron cell line, which may represent early events in the cascade of processes leading to injury and death of susceptible cells.

Intracellular calcium chelator BAPTA protects cells against toxic calcium overload but also alters physiological calcium responses

The effect of the membrane-permeant calcium chelator 1,2-bis-(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl) ester (BAPTA/AM) on ionomycin-induced cellular calcium overload was studied in single differentiated NH15-CA2 neuroblastoma x glioma hybrid cells. To monitor [Ca2+]i we used the fluorescent indicator Fura-2. Preincubation of the cells with 3 microM BAPTA/AM reduced the number of cells showing deregulation of [Ca2+]i during ionomycin-induced calcium influx. The calcium transients elicited by application of KCl were also severely affected by the chelator. These transients, although varying from cell to cell in shape, amplitude and duration, are well reproducible in individual cells. After incubation of cells for 1 h with 0.3-30 microM BAPTA/AM the time course of these cellular transients was markedly slowed. At 1 microM BAPTA/AM, the time constant of decline of [Ca2+]i was increased by a factor of 4.1 +/- 2.4 (n = 14) and the amplitude was reduced to about 50%. With 30 microM BAPTA/AM, the K(+)-induced calcium transients were almost completely inhibited. We conclude that intracellularly loaded calcium chelators may be used for the prevention of [Ca2+]i-induced cell damage, however, at the expense of a disturbed calcium signalling.

Immunoassays fail to detect antibodies against neuronal calcium channels in amyotrophic lateral sclerosis serum

Recent studies suggested that autoantibodies that bind to voltage-dependent calcium channels and activate calcium entry may play a role in the progressive degeneration of motoneurons in sporadic amyotrophic lateral sclerosis. Immunoassays were performed to assess autoantibody titer in patients with amyotrophic lateral sclerosis or Lambert-Eaton myasthenic syndrome, a disease in which the presence of anti-calcium channel antibodies is well documented. Based on immunoprecipitation assays for antibodies against N-type calcium channels, only 8% (2/25) of amyotrophic lateral sclerosis patients had marginally positive titers, whereas 58% (18/31) of patients with Lambert-Eaton myasthenic syndrome had positive titers. Enzyme-linked immunosorbent assays with purified neuronal N-type calcium channels revealed immunoreactivity in 2 of 25 amyotrophic lateral sclerosis sera and 12 of 31 Lambert-Eaton myasthenic syndrome sera, which is not compatible with suggestions that enzyme-linked immunosorbent assay is a more sensitive technique for the detection of autoantibodies in amyotrophic lateral sclerosis. Furthermore, based on immunoprecipitation assays, amyotrophic lateral sclerosis sera were totally negative for antibodies against L-type calcium channels from skeletal muscle or brain. These data do not support the hypothesis that an autoimmune response against calcium channels plays a primary role in amyotrophic lateral sclerosis.

Expression of calbindin-D28K in motoneuron hybrid cells after retroviral infection with calbindin-D28K cDNA prevents amyotrophic lateral sclerosis IgG-mediated cytotoxicity

Calbindin-D28K and/or parvalbumin appear to influence the selective vulnerability of motoneurons in amyotrophic lateral sclerosis (ALS). Their immunoreactivity is undetectable in motoneurons readily damaged in human ALS, and in differentiated motoneuron hybrid cells [ventral spinal cord (VSC 4.1 cells)] that undergo calcium-dependent apoptotic cell death in the presence of ALS immunoglobulins. To provide additional evidence for the role of calcium-binding proteins in motoneuron vulnerability, VSC 4.1 cells were infected with a retrovirus carrying calbindin-D28K cDNA under the control of the promoter of the phosphoglycerate kinase gene. Differentiated calbindin-D28K cDNA-infected cells expressed high calbindin-D28K and demonstrated increased resistance to ALS IgG-mediated toxicity. Treatment with calbindin-D28K antisense oligodeoxynucleotides, which significantly decreased calbindin-D28K expression, rendered these cells vulnerable again to ALS IgG toxicity.

A clinical trial of verapamil in amyotrophic lateral sclerosis

Seventy-two patients with amyotrophic lateral sclerosis (ALS) were enrolled in a clinical trial of the efficacy of verapamil in the treatment of ALS. In period 1 (pretreatment, months 1-3) and period 3 (posttreatment, months 10-12), patients received no drug. In period 2 (months 4-9), patients received verapamil. The slopes of declining pulmonary function and limb megascores were not significantly different during drug treatment compared to natural history and washout periods. Thus, verapamil was ineffective in slowing the clinical progression in ALS patients. Controlled trials using a natural history period may represent a faster and less expensive method of screening drugs for ALS compared to placebo-controlled trials.

Dialysable lymphocyte extract (DLyE) in infantile onset autism: a pilot study

40 infantile autistic patients were studied. They ranged from 6 years to 15 years of age at entry. 22 were cases of classical infantile autism; whereas 18 lacked one or more clinical defects associated with infantile autism ("pseudo-autism"). Of the 22 with classic autism, 21 responded to transfer factor (TF) treatment by gaining at least 2 points in symptoms severity score average (SSSA); and 10 became normal in that they were main-streamed in school and clinical characteristics were fully normalized. Of the 18 remaining, 4 responded to TF, some to other therapies. After cessation of TF therapy, 5 in the autistic group and 3 of the pseudo-autistic group regressed, but they did not drop as low as baseline levels.

Apoptosis induced by beta-N-oxalylamino-L-alanine on a motoneuron hybrid cell line

It has been suggested that beta-N-oxalylamino-L-alanine, a non-protein amino acid present in the Lathyrus Sativus seeds, may play a role in the etiopathogenesis of neurolathyrism, a toxic form of motor neuron disease clinically characterized by a severe spastic paraparesis. In order to investigate the mechanisms of beta-N-oxalylamino-L-alanine-mediated cell death, we studied the effect of this neurotoxin as well as other excitatory amino acids agonists on the growth and survival of motoneuron hybrid ventral spinal cord 4.1 cells. beta-N-oxalylamino-L-alanine was toxic to ventral spinal cord 4.1 cells in a concentration-dependent fashion (0.5-10 mM). Among the excitatory amino acids tested, only glutamate (1-10 mM), quisqualate (1 mM) and, with less extent, beta-N-methylamino-L-alanine (10 mM) induced a significant reduction of cell survival. The effect of Lathyrus Sativus neurotoxin was a slow process, becoming apparent only after 24-48 h of incubation. Interestingly, a mathematical analysis applied to the time course and dose curve of beta-N-oxalylamino-L-alanine toxicity suggested that even for very low concentrations of the amino acid it is theoretically possible to predict a time-dependent effect. The cell death was not blocked by antagonists of N-methyl-D-aspartate or non-N-methyl-D-aspartate receptors; aurintricarboxylic acid and alpha-tocopherol gave a partial protection; cysteine (1 mM) prevented the toxic effect of both Lathyrus Sativus neurotoxin and glutamate as well as quisqualate. Morphologically, in the presence of either beta-N-oxalylamino-L-alanine, glutamate or quisqualate, ventral spinal cord 4.1 cells showed apoptotic features also confirmed by ISEL technique and agarose gel electrophoresis of genomic DNA. Thus, our results suggest that in ventral spinal cord 4.1 motoneuron hybrid cells, in the absence of functional synaptic excitatory amino acid receptors, beta-N-oxalylamino-L-alanine induces cell degeneration through an apoptotic mechanism, possibly mediated by a block of cystine/glutamate Xc antiporter.

Ultrastructural evidence for altered calcium in motor nerve terminals in amyotropic lateral sclerosis

Numerous studies of amyotrophic lateral sclerosis have suggested that increased intracellular calcium is a common denominator in motoneuron injury. In experimental models, IgG from patients with amyotrophic lateral sclerosis enhanced calcium entry and induced apoptotic cell death in vitro as well as increased intracellular calcium and induced ultrastructural alterations of the motor nerve terminals in mice in vivo. To determine whether similar increases in intracellular calcium and altered morphology are present in motor nerve terminals of amyotrophic lateral sclerosis patients in vivo, muscle biopsy specimens from 7 patients with amyotrophic lateral sclerosis, 10 nondenervating disease control subjects, and 5 patients with denervating neuropathies were analyzed with ultrastructural techniques, employing oxalate-pyroantimonate fixation to preserve in situ calcium distribution. Motor nerve terminals from amyotrophic lateral sclerosis specimens contained significantly increased calcium, increased mitochondrial volume, and increased numbers of synaptic vesicles compared to any of the disease control groups, without exhibiting excess Schwann envelopment specific to denervating terminals. These results parallel the effect of amyotrophic lateral sclerosis IgG passively transferred to mice, and provide the first demonstration that neuronal calcium is, in fact, increased in amyotrophic lateral sclerosis in vivo.

Antibodies to calcium channels from ALS patients passively transferred to mice selectively increase intracellular calcium and induce ultrastructural changes in motoneurons

Antibodies to Ca channels in ALS patients IgG can be demonstrated to enhance Ca current and cause cell injury and death in a motoneuron cell line in vitro. To determine whether these antibodies can alter neuronal calcium homeostasis in vivo IgG fractions from six ALS patients were injected intraperitoneally into mice, and neurons assayed by ultrastructural techniques for calcium content. After 24 h, all six ALS IgG by (40 mg/animal) increased vesicle number in spinal motoneuron axon terminals, and in boutons synapsing on spinal motoneurons. Using the oxalate-pyroantimonate technique for calcium precipitation, these antibodies produced dose-dependent calcium increases either in axon terminal synaptic vesicles and mitochondria, or in rough endoplasmic reticulum, mitochondria, and Golgi complex of spinal motoneuron and frontal cortex pyramidal cells. ALS IgG was itself internalized and also induced neurofilament H phosphorylation. The observed changes in ultrastructure and calcium compartmentation were restricted to motoneurons; normal and disease control IgG, which did not possess antibodies enhancing calcium entry, did not exert similar effects. These data demonstrate that ALS IgG containing Ca-channel antibodies can alter calcium homeostasis of motoneurons in vivo.

Mechanisms in motor neurone disease: clues from genetic studies

Motor neurone disease is a rapidly progressive neurodegenerative disorder, characterized by muscular weakness and wasting with fasciculation and by spasticity. While most cases are sporadic, approximately 10% are inherited in an autosomal dominant mode. Recently, mutations in the gene encoding the free-radical scavenging enzyme superoxide dismutase-1 have been found to segregate with the disorder in 20% of familial cases. This is an exciting development, as free radical damage has long been implicated in the pathogenesis of motor neurone disease and it raises the possibility of novel therapeutic approaches in this otherwise fatal condition.