Expression of metabotropic glutamate receptor mRNAs in the human spinal cord: implications for selective vulnerability of spinal motor neurons in amyotrophic lateral sclerosis

To elucidate the relevance of metabotropic glutamate receptors (mGluRs) to the selective vulnerability of motor neurons in the spinal cord in patients with amyotrophic lateral sclerosis (ALS), we investigated the distribution of mRNAs coding mGluR1-5 in the normal human spinal cord. The mRNAs for mGluR1, 4 and 5 were observed in the spinal gray matter, whereas mGluR2 mRNA was absent in the spinal cord and mGluR3 mRNA was displayed only on glial cells in the white matter. Signals for mGluR1 and mGluR5 were enriched in the dorsal horn, while mGluR4 mRNA was abundant in the ventral horn. Since agonists to group I mGluRs (mGluR 1 and 5) have been demonstrated to have neuroprotective effects on spinal motor neurons, less expression of mRNAs coding mGluR1 and mGluR5 in the ventral horn than in the dorsal horn may be implicated in the selective susceptibility of spinal motor neurons in ALS.     

Differentiation and migration of astrocytes in the spinal cord following dorsal root injury in the adult rat

Nerve fibre degeneration in the spinal cord is accompanied by astroglial proliferation. It is not known whether these cells proliferate in situ or are recruited from specific regions harbouring astroglial precursors. We found cells expressing nestin, characteristic of astroglial precursors, at the dorsal surface of the spinal cord on the operated side from 30 h after dorsal root injury. Nestin-expressing cells dispersed to deeper areas of the dorsal funiculus and dorsal horn on the operated side during the first few days after injury. Injection of bromodeoxyuridine (BrdU) 2 h before the end of the experiment, at 30 h after injury, revealed numerous BrdU-labelled, nestin-positive cells in the dorsal superficial region. In animals surviving 20 h after BrdU injection at 28 h postlesion, cells double-labelled with BrdU and nestin were also found in deeper areas. Labeling with BrdU 2 h before perfusion showed proliferation of microglia and radial astrocytes in the ventral and lateral funiculi on both sides of the spinal cord 30 h after injury. Nestin-positive cells coexpressed the calcium-binding protein Mts1, a marker for white matter astrocytes, in the dorsal funiculus, and were positive for glial fibrillary acidic protein (GFAP), but negative for Mts1 in the dorsal horn. One week after injury the level of nestin expression decreased and was undetectable after 3 months. Taken together, our data indicate that after dorsal root injury newly formed astrocytes in the degenerating white and grey matter first appear at the dorsal surface of the spinal cord from where some of them subsequently migrate ventrally, and differentiate into white- or grey-matter astrocytes.     

Cellular distribution of vascular endothelial growth factor A (VEGFA) and B (VEGFB) and VEGF receptors 1 and 2 in focal cortical dysplasia type IIB

Members of the vascular endothelial growth factor (VEGF) family are key signaling proteins in the induction and regulation of angiogenesis, both during development and in pathological conditions. However, signaling mediated through VEGF family proteins and their receptors has recently been shown to have direct effects on neurons and glial cells. In the present study, we immunocytochemically investigated the expression and cellular distribution of VEGFA, VEGFB, and their associated receptors (VEGFR-1 and VEGFR-2) in focal cortical dysplasia (FCD) type IIB from patients with medically intractable epilepsy. Histologically normal temporal cortex and perilesional regions displayed neuronal immunoreactivity (IR) for VEGFA, VEGFB, and VEGF receptors (VEGFR-1 and VEGFR-2), mainly in pyramidal neurons. Weak IR was observed in blood vessels and there was no notable glial IR within the grey and white matter. In all FCD specimens, VEGFA, VEGFB, and both VEGF receptors were highly expressed in dysplastic neurons. IR in astroglial and balloon cells was observed for VEGFA and its receptors. VEGFR-1 displayed strong endothelial staining in FCD. Double-labeling also showed expression of VEGFA, VEGFB and VEGFR-1 in cells of the microglia/macrophage lineage. The neuronal expression of both VEGFA and VEGFB, together with their specific receptors in FCD, suggests autocrine/paracrine effects on dysplastic neurons. These autocrine/paracrine effects could play a role in the development of FCD, preventing the death of abnormal neuronal cells. In addition, the expression of VEGFA and its receptors in glial cells within the dysplastic cortex indicates that VEGF-mediated signaling could contribute to astroglial activation and associated inflammatory reactions.     

Induction of the immediate early gene c-jun in human spinal cord in amyotrophic lateral sclerosis with concomitant loss of NMDA receptor NR-1 and glycine transporter mRNA

The aetiology of the sporadic form of amyotrophic lateral sclerosis (ALS) is poorly understood although abnormalities in glutamate and glycine transport have been implicated which both could contribute to a neurodegenerative process mediated through the N-methyl-d-aspartate (NMDA) receptor. In this study we have used in situ hybridization to investigate whether any changes in the expression of NMDA receptors, the glycine transporter or glutamate-mediated injury responses are detectable in ALS. Two immediate early genes were investigated as markers of neuronal injury responses, c-jun and zif-268, both constitutively expressed in the spinal cord. Levels of c-jun mRNA were most abundant in intermediate grey and layer IX of the ventral horn containing motor neurones. This pattern was markedly changed in ALS with large increases (2–3 fold) in c-jun mRNA occurring in dorsal and ventral horn. The marked increase in c-jun mRNA was also substantiated by slot blot analysis of tissue homogenates of spinal cord and a parallel induction of zif-268 mRNA was also seen. NMDA receptor NR-1 mRNA was widely distributed in control spinal cord with the highest concentrations occurring in layers IX, X, intermediate grey and dorsal horn. The ALS cases showed a selective decrease in the level of NR-1 mRNA in the ventral region (50%) whilst no significant decrease was detected in the dorsal region. Quantitation of tissue homogenates with dorsal and ventral regions combined also yielded a significant decrease of 40% which supports the analysis from in situ hybridization densitometry. The distribution of the glycine transporter was characterised with an oligonucleotide probe and showed a specific localisation to motor neurones of the ventral horn, layer II of the dorsal horn and low levels throughout grey matter. In cases of ALS, substantial and selective loss (75%) of the glycine transporter occurred in ventral grey matter (P < 0.001) with little change occurring in dorsal grey matter. This deficit was also s was also substantiated by slot blot analysis of tissue homogenates where a decrease of 59% was obtained (P < 0.005). The induction of c-jun and zif-268 detected in ALS spinal cord in this study indicates the presence of a potential cellular response to neuronal ‘stress’ that may play an important role in subsequent neurodegenerative or reparative mechanisms.     

Protein‐bound crotonaldehyde accumulates in the spinal cord of superoxide dismutase‐1 mutation‐associated familial amyotrophic lateral sclerosis and its transgenic mouse model

Growing evidence documents oxidative stress involvement in ALS. We previously demonstrated accumulation of a protein‐bound form of the highly toxic lipid peroxidation product crotonaldehyde (CRA) in the spinal cord of sporadic ALS patients. In the present study, to the determine the role for CRA in the disease processes of superoxide dismutase‐1 (SOD1) mutation‐associated familial ALS (FALS), we performed immunohistochemical and semiquantitative cell count analyses of protein‐bound CRA (P‐CRA) in the spinal cord of SOD1‐mutated FALS and its transgenic mouse model. Immunohistochemical analysis revealed increased P‐CRA immunoreactivity in the spinal cord of the FALS patients and the transgenic mice compared to their respective controls. In the FALS patients, P‐CRA immunoreactivity was localized in almost all of the chromatolytic motor neurons, neurofilamentous conglomerates, spheroids, cordlike swollen axons, reactive astrocytes and microglia, and the surrounding neuropil in the affected areas represented by the anterior horns. In the transgenic mice, P‐CRA immunoreactivity was localized in only a few ventral horn glia in the presymptomatic stage, in almost all of the vacuolated motor neurons and cordlike swollen axons and some of the ventral horn reactive astrocytes and microglia in the onset stage, and in many of the ventral horn reactive astrocytes and microglia in the advanced stage. Cell count analysis on mouse spinal cord sections disclosed a statistically significant increase in the density of P‐CRA‐immunoreactive glia in the ventral horns of the young to old G93A mice compared to the age‐matched control mice. The present results indicate that enhanced CRA formation occurs in motor neurons and reactive glia in the spinal cord of SOD1‐mutated FALS and its transgenic mouse model as well as sporadic ALS, suggesting implications for CRA in the pathomechanism common to these forms of ALS.     

GABA- and glycine-immunoreactive neurons in the spinal cord of the carp,Cyprinus carpio

γ-Aminobutyric acid (GABA) and glycine are the two main inhibitory transmitter amino acids in the central nervous system of vertebrates. The distribution of cells containing GABA and glycine in the carp spinal cord was examined by using specific antisera raised against the two amino acids conjugated to bovine serum albumin. The immunoreaction on serial paraffin sections was visualized by a streptavidin-biotin method. Both antisera gave highly specific labellings of cells. At least three types of GABA-immunoreactive cells were found. They were small cells in the dorsal grey matter, various sized cells in the central and ventral grey, and some ependymal cells contacting the central canal. In addition, very small cells and neuropil structures in the dorsal horn were strongly immunoreactive to the GABA serum. Certain cells in the ventral horn have moderate numbers of labelled synaptic boutons on the perikarya, but very few GABA-labelled terminals were found on putative motoneurons. The immunoreactive ependymal cells appeared to have a ventrolaterally directed axon. The glycine antiserum labelled small and intermediate cells in the dorsal grey, large, elongated cells in the median region, and varying sized cell sin the ventral grey. The numbers and density of immunoreactive cells and neuropil strucures in the ventral horn were fewer and lower than in GABA-stained sections. The median large cells had a thick venrolateral process. The ventral intermediate cells were often found near putative motoneurons. Labelled synaptic boutons were present on most ventral cells including putative motoneurons and interneurons. Abundant distribution of cells immunoreactive to both antisera suggest important roles of both GABA and glycine as neurotransmitters for controlling swimming movements in teleosts. © 1993 Wiley-Liss, Inc.     

Upregulation of HSP27 in a transgenic model of ALS

Mutations of the SOD1 gene underlie 1 form of familial amyotrophic lateral sclerosis (ALS). Their pathogenic mechanism remains uncertain, but is thought to involve oxidative stress and abnormal protein aggregation, 2 processes known to induce heat shock proteins (HSPs). We studied the expression of 3 HSPs (alphaB-crystallin, HSP27, and HSP70) in transgenic mice overexpressing human mutant (G93A and G37R) SOD1, using a combination of immunohistochemistry and immunoblotting. Quantitative Western blot analysis demonstrated alphaB-crystallin and HSP27 to be upregulated in the spinal cord of mutant SOD1 mice compared to mice overexpressing wild-type SOD1. HSP70 levels were normal. Immunocytochemical studies of the ventral horn of the spinal cord demonstrated HSP27 to be localized in the nucleus of neurons and glial cells in presymptomatic and early symptomatic animals, where it often was punctate in pattern. In the later stages of the disease, HSP27 was predominantly present in the cytoplasm of reactive glial cells. The early nuclear localization was confirmed by Western blot analysis of spinal cord nuclear and cytoplasmic fractions. In contrast to HSP27, alphaB-crystallin was localized exclusively in the cytoplasm of reactive glial cells.     

Increased expression of connective tissue growth factor in amyotrophic lateral sclerosis human spinal cord

Connective tissue growth factor (CTGF) is a secreted protein involved in a variety of cellular events such as survival, proliferation, and extracellular matrix production. Recent studies suggest a role for this protein also in the repair processes of the central nervous system. The distribution and significance of CTGF in human brain is, however, poorly understood, particularly under pathological conditions. In the present study the expression of CTGF protein was investigated in the spinal cord of control and both sporadic and familial amyotrophic lateral sclerosis (sALS and fALS) patients. Western blot analysis showed a consistent increase in CTGF expression in six sALS patients compared with controls. Immunoreactivity signal for CTGF was equally present in blood vessels of control and ALS spinal cord, but was dramatically increased in reactive astrocytes of the ventral horn and white matter in both sALS and fALS. Increased expression was also observed in the cytoplasm of motor neurons of sALS and fALS patients with long duration of the disease. Our data indicate a role for CTGF in the complex reactive process that is associated with the progression of ALS spinal cord damage. The up-regulation in reactive astrocytes supports a role for CTGF in the molecular mechanisms underlying astrogliosis. However, the altered CTGF expression observed in neurons might represent an additional mechanism involved in motor neuron dysfunction and changes in glial-neuronal communication in the course of the neurodegenerative process.The first two authors contributed equally to the present work.     

Ubiquitin and heat shock protein expression in amyotrophic lateral sclerosis

The expression of two heat shock proteins, HSP72 and p57, in addition to ubiquitin, has been studied immunocytochemically in nine amyotrophic lateral sclerosis (ALS) cases and 10 age-matched controls. HSP72 and p57 antibodies did not identify the characteristic ubiquitin-immunoreactive inclusions present in anterior horn cells in ALS spinal cord. Antibodies to HSP72, but not to p57 or ubiquitin, strongly labelled structures corresponding to polyglucosan bodies in spinal grey matter. Such immunoreactive profiles were more abundant in ALS cases, although they were also present in control material. They were sometimes identified by haematoxylin and eosin and periodic acid Schiff reaction, but were not labeled by phosphotungstic acid haematoxylin or by antibodies to glial fibrillary acidic protein. Although ubiquitin, HSP72 and p57 are stress-induced proteins, they are expressed differently and might therefore have different significance in neuronal degeneration.     

Recruitment of activated microglia cells in the spinal cord of mice by ALS IgG

Mice were injected i.p. with IgG samples of different patients to test whether IgG from amyotrophic lateral sclerosis (ALS) can initiate an immune/inflammatory reaction targeting motor neurons. All IgG samples of five ALS patients and none of the disease controls recruited activated microglia cells in the ventral horn of the spinal cord. CD3 lymphocytes were not accumulated in the same tissue. Similar reaction was evoked by injection of IgG from guinea pigs with experimental autoimmune gray matter disease (EAGMD) induced by immunization with the homogenate of the ventral horn of bovine spinal cord. The results indicate that ALS IgG and anti-motoneuron IgG induce microglia reaction targeting motor neurons without initiating T cell response in the recipient mice.     

Induction of type IV collagen and other basement-membrane-associated proteins after spinal cord injury of the adult rat may participate in formation of the glial scar.

We investigated the spatial and temporal expression of basement-membrane-forming and neurite-outgrowth-supporting matrix proteins after a unilateral dorsal root injury combined with a collagen I/laminin-1 graft and a stab wound lesion to the dorsal horn of the adult rat spinal cord. Ten days after injury, the gamma1 laminin was induced in the reactive glia. At this early stage, the glial cells failed to express type IV collagen and the alpha1 laminin. One month after injury, reactive astrocytes in the dorsal horn of the lesioned side expressed gamma1 laminin, type IV collagen, and the alpha1 laminin whereas astrocytes of the normal spinal cord or the uninjured contralateral dorsal horn were negative. Both astrocytes and neurons of the ipsilateral ventral horn were induced to express laminin-1 and gamma1 laminin. Astrocytes of the ipsilateral ventral horn also expressed type IV collagen. Simultaneously with the changes in expression of the extracellular matrix proteins, the expression pattern of basic fibroblast growth factor (FGF-2) was markedly altered after spinal cord injury. In normal and contralateral spinal cord, FGF-2 was expressed in nerve fibers, but its expression changed from neuronal into glial in the ipsilateral spinal cord within 1 month after injury. Four months after injury, expression of both type IV collagen and the alpha1 laminin had declined, but the astrocytes at the injury site continued expressing the gamma1 laminin. Cultured astrocytes were negative for type IV collagen, but several cytokines, including IL-1beta and TGFbeta1, induced expression of type IV collagen in the astrocytes. These factors also increased deposition of type IV collagen matrix in the glial cultures. These results indicate that type IV collagen and the alpha1 laminin are induced in reactive astrocytes after spinal cord injury in vivo. Induction of type IV collagen in astrocytes in vitro by cytokines indicates that blood-borne or local factors at the injury site may induce the spinal cord glial expression of type IV collagen in vivo. Simultaneous expression of laminin-1 and alpha1 laminin with type IV collagen is known to lead to production of basement membranes. This may hamper the neurite-outgrowth-promoting potential of the gamma1 laminin by initiating formation of the glial scar.     

Aluminum, calcium, and iron in the spinal cord of patients with sporadic amyotrophic lateral sclerosis using laser microprobe mass spectroscopy: a preliminary study

We measured aluminum (Al), calcium (Ca), and iron (Fe) levels in neuronal cytoplasm and nucleus, capillaries, and neuropil in samples of ventral cervical spinal cord from 5 patients with sporadic amyotrophic lateral sclerosis (ALS) and 5 age-matched controls using laser microprobe mass spectrometry (LMMS). The concentration of Al was not altered in any area in the ALS samples. In contrast, Fe and Ca were increased 1.5-2-fold in the nucleus and cytoplasm of ALS neurons but not in capillaries and neuropil. These findings do not support the hypothesis that Al is enriched in spinal cord of sporadic ALS as has been reported for Guamanian ALS/Parkinson's dementia. The elevations of Fe in spinal neurons are consistent with reports of increased Fe in bulk samples of ALS spinal cord. The presence of increased Fe within spinal neurons may be significant in the pathogenesis of motor neuron degeneration by catalyzing the generation of reactive oxygen species within specific cells.     

GDNF, RET and GFRalpha-1-3 mRNA expression in the developing human spinal cord and ganglia.

The identification of endogenous neurotrophic factors and their receptors in human spinal cord is important not only to understand development, but also in the consideration of possible future therapies for neurodegenerative disorders and trauma. Using in situ hybridization, the expression of glial cell line-derived neurotrophic factor (GDNF), neurturin (NTN), persephin (PSP), GFRalpha-1, GFRalpha-2, GFRalpha-3 and RET mRNA in human fetal spinal cord was studied. Strong GDNF mRNA hybridization signal, presumably restricted to Clarke's nucleus, was detected in the thoracic spinal cord. mRNA encoding GFRalpha-1 was expressed in the entire spinal cord gray matter with particularly high expression in the ventral horn. GFRbeta-1 was also expressed more weakly in dorsal root ganglia. NTN and persephin mRNA were not detected in either the fetal spinal cord or the dorsal root ganglia. mRNA coding for GFRalpha-2, however, was found in most cells of the spinal cord gray matter. A strong expression of GFRalpha-3 mRNA was detected in dorsal root ganglia cells and Schwann cells. The transducing receptor RET was expressed strongly in motorneurons and dorsal root ganglion neurons. We conclude that basic features concerning the role of the GDNF family of ligands and their receptors revealed in rodents applies to humans.     

Morphological evidence for lipid peroxidation and protein glycoxidation in spinal cords from sporadic amyotrophic lateral sclerosis patients

For determining whether both the spinal cord motor neurons and glial cells are exposed to increased oxidative stress in amyotrophic lateral sclerosis (ALS), we performed an immunohistochemical investigation of end products of lipid peroxidation and protein glycoxidation in spinal cords from seven sporadic ALS patients and seven age-matched control individuals. In the ALS spinal cords, immunoreactivities for adducts of 4-hydroxy-2-nonenal-histidine and crotonaldehyde-lysine as markers of lipid peroxidation, N(epsilon)-(carboxymethyl)lysine as a marker of lipid peroxidation or protein glycoxidation, and pentosidine as a marker of protein glycoxidation were localized in the gray matter neuropil and almost all of the motor neurons, reactive astrocytes and microglia/macrophages, whereas none of the immunoreactivities for N(epsilon)-(carboxyethyl)lysine or argpyrimidine as markers of protein glycoxidation or enzymatic glycolysis, or pyrraline or imidazolone as markers of nonoxidative protein glycation were detectable. The control spinal cords displayed no significant immunoreactivities for any of these examined products. Our results indicate that in sporadic ALS, both lipid peroxidation and protein glycoxidation are enhanced in the spinal cord motor neurons and glial cells, and suggest that the formation of certain products in these abnormal reactions is implicated in motor neuron degeneration.     

Amyotrophic lateral sclerosis: glutamate dehydrogenase and transmitter amino acids in the spinal cord.

Measurements were taken of the activity of glutamate dehydrogenase (GDH) and the levels of transmitter amino acids in anatomically dissected regions of cervical and lumbar spinal cord in eight patients dying with amyotrophic lateral sclerosis (ALS) and in 11 neurologically normal controls. GDH activity was considerably increased in lateral and ventral white matter and in the dorsal horn of the ALS cervical spinal cord, but normal in the ventral horn and the dorsal columns. Similar, although less pronounced, GDH changes were found in the lumbar enlargement. The mean concentrations of aspartate and glutamate were reduced in all regions of ALS spinal cord investigated. Taurine concentrations were significantly increased in several subdivisions of cervical spinal cord, but normal in lumbar regions. Glycine levels were significantly reduced in lumbar ventral and dorsal horns. There was no striking change in spinal cord GABA levels in our ALS patients. It is suggested that the reduced levels of glutamate and aspartate as well as the elevated GDH activity in the spinal cord of ALS patients may reflect an overactivity of the neurons releasing these potentially excitotoxic amino acids and thus may be causally related to the spinal neuro-degenerative changes characteristic of ALS.     

White-matter dendrites in the upper cervical spinal cord of the adult cat: A light and electron microscopic study

The organization and structure of dendrites penetrating into the white matter of upper cervical spinal segments have been examined by means of Golgi staining techniques, intracellular horseradish peroxidase (HRP) injections, and ultrastructural studies. The Golgi studies established that several groups of neurons located in intermediate and ventral laminae of the upper cervical spinal cord have a substantial part of their dendritic tree extending into adjacent ventral and lateral funiculi. Most dendrites in white matter showed irregular varicosities along their length. They were devoid of spines and followed relatively direct paths. In contrast, grey matter dendrites were occasionally observed with spines and complex appendages and frequently followed tortuous paths. The size and location of some Golgi stained neurons suggested that white matter dendrites might originate from neck muscle motoneurons. This possibility was confirmed using intracellular HRP injections. These studies also showed that the distribution of white matter dendrites of neck muscle motoneurons depended on the location of the motoneuron soma. White matter dendrites of neck muscle motoneurons located deep in the ventral horn projected into all regions of white matter surrounding the ventral horn. Other neck muscle motoneurons, located in the spinal accessory nucleus, had white matter dendrites largely confined to the lateral funiculus. White matter dendrites of motoneurons in the commissural nucleus were found to project across the ventral commissure into the contralateral spinal cord. Light microscopic studies of semi-thin sections stained with toluidine blue and electron microscopic studies of thin sections revealed that white matter dendrites were confined to special regions of the white matter. These regions resembled the grey matter neuropil and contained dendrites and unmyelinated and small diameter myelinated axons. Axon terminals were also found in white matter. These terminals contained either flattened or spherical vesicles and formed synaptic contacts on white matter dendrites. White matter dendrites, by virtue of their frequency of occurrence, distribution, and type of synaptic contacts may represent a means by which descending or ascending spinal systems can influence spinal neurons without recourse to axon collaterals which terminate in grey matter.     

Innervation of the spinal cord by sympathetic fibers

Pharmacologic and neurochemical studies suggest that catecholamines are still present below the level of transection in the spinal cord of the chronic spinal animal, despite the degeneration of bulbospinal catecholamine pathways. Histofluorescence studies of rat and dog spinal cord revealed noradrenergic fibers and varicosities remaining in the chronically decentralized spinal cord which can account for the low concentrations of norepinephrine (NE) found below the transection. The fibers appear to enter the spinal cord with blood vessels through the anterior median fissure, and are probably of sympathetic origin. In the spinal cord, these fibers can dissociate from blood vessels and continue through the neuropil; they are associated with neurons in the ventral horn and occasionally in the central gray. These peripheral sympathetic fibers may influence motor systems and other nervous functions.     

Immune reactivity in a mouse model of familial ALS correlates with disease progression

OBJECTIVE: The cause of motor neuron death in ALS is incompletely understood. This study aims to define the potential involvement of nonneuronal immune-inflammatory factors in the destruction of motor neurons in mutant superoxide dismutase-1 (SOD1) transgenic mice as a model of ALS. BACKGROUND: The presence of activated microglia, IgG and its receptor for Fc portion (FcgammaRI), and T lymphocytes in the spinal cord of both patients with ALS and experimental animal models of motor neuron disease strongly suggests that immune-inflammatory factors may be actively involved in the disease process. METHODS: The expression of immune-inflammatory factors was followed in both human mutant (G93A) SOD1 transgenic mice and human wild-type SOD1 transgenic mice, at different ages (40, 80, and 120 days). Fixed, frozen, free-floating sections of the lumbar spinal cord were stained with antibodies against CD11b, IgG, FcgammaRI, intercellular adhesion molecule-1 (ICAM-1), CD3, and glial fibrillary acidic protein. RESULTS: The earliest change observed was the upregulation of ICAM-1 in the ventral lumbar spinal cord of 40-day-old mutant SOD1 mice. IgG and FcgammaRI reactivities were detected on motor neurons as early as 40 days and on microglial cells at later stages. Microglial activation was first evident in the ventral horn at 80 days, whereas reactive astrocytes and T cells became most prominent in 120-day-old mutant SOD1 mice. CONCLUSION: The upregulation of proinflammatory factors during early presymptomatic stages as well as the expansion of immune activation as disease progresses in mutant SOD1 transgenic mice suggest that immune-inflammatory mechanisms could contribute to disease progression.