Biomedical subjects

I Ferrer

Publications and source records attributed to I Ferrer.

At least 19 recordsLinked to original sources

PubMed2003

Primary progressive aphasia as the initial manifestation of corticobasal degeneration and unusual tauopathies.

The clinical, neuroradiological, neuropathological and biochemical findings in four patients with primary progressive aphasia and tauopathy are described. The aphasic syndrome preceded by several years the appearance of other symptoms in every case. Asymmetrical apraxia with alien hand phenomenon occurred in one case. Frontotemporal symptoms occurred in three cases, but progressed to dramatic cognitive devastation in only one of these. Generalized dementia consistent with probable Alzheimer's disease (AD) developed with time in another. Cerebral computer tomography scans, magnetic resonance imaging and SPECT studies revealed marked asymmetries in one case, and showed nonspecific cerebral atrophy in the remaining ones. The neuropathological examination revealed typical corticobasal degeneration (CBD) in one case; CBD and AD in another; and atypical CBD, argyrophilic grain disease (AGD) and alpha-synucleinopathy consistent with Parkinson's disease in a third. Unique neuropathological findings were found in the remaining case. This was characterized by severe cerebral atrophy, marked neuronal loss in the cerebral cortex and abnormal tau deposition in neurons of the cerebral cortex, diencephalon and brain stem. Ballooned neurons, Pick bodies, generalized cortical neurofibrillary tangles and astrocytic plaques were absent. However, massive globular inclusions, containing phospho-tau, occurred in glial cells, mainly oligodendrocytes, in the white matter. Biochemical studies of frontal homogenates revealed four bands of 73/74, 68, 64 and 60 kDa of phosphorylated tau (using antibodies recognizing phospho-tau Thr181, Ser262 and Ser422) in the patient with AD and CBD, suggesting a predominant AD pattern in this case. Two bands of 68 and 64 kDa of phospho-tau were recovered in the sarkosyl-insoluble fraction in the other three cases. This pattern is similar to that found in CBD, progressive supranuclear palsy and AGD. Taken together, the present series further supports pure and combined CBD as causes of primary progressive aphasia, and they extend the hypothesis that primary progressive aphasia may be the initial symptom of distinct tauopathies.

Aged↗

PubMed2003

GluR2/3, NMDAepsilon1 and GABAA receptors in Creutzfeldt-Jakob disease.

The excitatory ionotropic glutamate receptors N-methyl- d-aspartate (NMDA) and alpha-amino-3-hydro-5methyl-4-isoxazole propionic acid (AMPA) receptors, and the inhibitory gamma-aminobutyric acid (GABA) receptors are major regulators of synaptic transmission in the central nervous system. Glutamate receptors AMPA GluR2/3 and NMDA R2A: NR2A (NMDAepsilon1), and GABA(A) (GABA(A) Ralpha1) receptors were examined by immunohistochemistry in the cerebral cortex (frontal cortex) entorhinal cortex, hippocampus and cerebellar cortex in nine patients with sporadic Creutzfeldt-Jakob disease (CJD) and eight age-matched controls obtained 3-8 h after death. All patients with CJD showed methionine/methionine in codon 129 of the prion protein gene. Decreased GluR2/3 immunoreactivity was found in the frontal cortex, entorhinal cortex and Purkinje cells; reduced NMDAepsilon1 immunoreactivity was found in the frontal cortex, entorhinal cortex, and molecular and granular cell layers of the cerebellum. Decreased GluR2/3 and NMDAepsilon1 immunoreactivity was also observed in the molecular layer of the dentate gyrus, but not in the hippocampus proper in cases with hippocampal involvement. GABA(A) Ralpha1 expression was markedly decreased in the granular cell layer of the cerebellum in CJD. Decreased GluR2/3 and NMDAepsilon1 expression correlated with prion protein deposition, neuron loss and spongiform degeneration in the cerebral cortex in every case. However, reduced GluR2/3 immunoreactivity in Purkinje cells was apparently independent of these parameters. In contrast to ionotropic glutamate receptors, GABA(A) Ralpha1 immunoreactivity was moderately increased in the frontal cortex, entorhinal cortex and molecular layer of the cerebellum in CJD. The present results show marked and selective abnormalities in the expression of crucial neurotransmitter receptors in CJD, ionotropic glutamate receptors being more severely affected than ionotropic GABA receptors. These findings stress selective vulnerability of glutamate receptors versus GABA receptors in CJD.

Aged↗

PubMed2003

Early modifications in the expression of mitogen-activated protein kinase (MAPK/ERK), stress-activated kinases SAPK/JNK and p38, and their phosphorylated substrates following focal cerebral ischemia.

Focal ischemia induced by middle cerebral artery occlusion (MCAO) to adult rats results in necrosis at the infarct core and activation of complex signal pathways for cell death and cell survival in the penumbra. Upstream from the cell death promoters and executioners are several kinases that, once activated by phosphorylation, may activate several transcription factor substrates involved in cell death and cell survival. In the present study we examined, by immunohistochemistry, the expression of phosphorylated (active) mitogen-activated protein kinase, extracellular signal-regulated kinase (MAPK/ERK), stress-activated protein kinase (SAPK), c-Jun N-terminal kinase (JNK) and p-38 kinase at early stages (1-4 h) following 1 h of MCAO in the rat. The expression of phosphorylation-dependent, active transcription substrates of these kinases, including cyclic AMP-responsive element-binding protein (CREB) Alk-1, ATF-2, c-Myc and c-Jun was examined at early stages following reperfusion. Increased nuclear phosphorylated SAPK/JNK (SAPK/JNK-P) and c-Jun-PSer63, and reduced CREB-P, occurred in the infarct core at 1 h following reperfusion, suggesting increased phosphorylated SAPK/JNK and c-JunSer63, together with decreased phospho-CREB associated with cell death in the infarct core. However, increased cytoplasmic expression of MAPK/ERK-P, SAPK/JNK-P, p38-P, CREB-P, Elk-1-P, c-Myc-P, ATF-2-P and c-Jun-P occurred in the region bordering the infarct core (penumbra) at 4 h following reperfusion. This indicates that different signals converge in the cytoplasm of neurons located at the borders of the infarct at 4 h following reperfusion, revealing the struggle of death promoters and life facilitators at the penumbra. Whether phosphorylated kinases and specific substrates participate in promoting cell death or survival in the penumbra probably depends on additional factors and on the interaction with other proteins.

Activating Transcription Factors↗

PubMed2003

Photodegradation of roxarsone in poultry litter leachates.

Arsenic compounds have been used extensively in agriculture in the US for applications ranging from cotton herbicides to animal feed supplements. Roxarsone (3-nitro-4-hydroxyphenylarsonic acid), in particular, is used widely in poultry production to control coccidial intestinal parasites. It is excreted unchanged in the manure and introduced into the environment when litter is applied to farmland as fertilizer. Although the toxicity of roxarsone is less than that of inorganic arsenic, roxarsone can degrade, biotically and abiotically, to produce more toxic inorganic forms of arsenic, such as arsenite and arsenate. Experiments were conducted on aqueous litter leachates to test the stability of roxarsone under different conditions. Laboratory experiments have shown that arsenite can be cleaved photolytically from the roxarsone moiety at pH 4-8 and that the degradation rate increases with increasing pH. Furthermore, the rate of photodegradation increases with nitrate and natural organic matter concentration, reactants that are commonly found in poultry-litter-water leachates. Additional photochemical reactions rapidly oxidize the cleaved arsenite to arsenate. The formation of arsenate is not entirely undesirable, because it is less mobile in soil systems and less toxic than arsenite. A possible mechanism for the degradation of roxarsone in poultry litter leachates is proposed. The results suggest that poultry litter storage and field application practices could affect the degradation of roxarsone and subsequent mobilization of inorganic arsenic species.

Animals↗

PubMed2003

Abnormal synaptic protein expression in two Arabian horses with equine degenerative myeloencephalopathy.

Numerous swollen neurons and multiple dystrophic axons were observed in the gracillis and cuneatus nuclei of two male Arabian horses, aged six and 12 months of age, with equine degenerative myeloencephalopathy. Swollen neurons and dystrophic axons showed synaptophysin, synaptosomal-associated protein of 25 kDa, syntaxin-1 and alpha-synuclein immunoreactivity. Moreover, dystrophic axons were strongly immunopositive against the ubiquitin protein and against the anti-phosphorylated 200 kDa neurofilament protein. Abnormal expression of integral synaptic vesicle, synaptic vesicle-associated presynaptic plasma membrane and cytosolic proteins, which participate in the trafficking, docking and fusion of the synaptic vesicle to the plasma membrane, suggest that severe disruption of axonal transport plays a crucial role in the pathogenesis of dystrophic axons in equine degenerative myeloencephalopathy (EDM).

Animals↗

PubMed2003

Tau phosphorylation and kinase activation in familial tauopathy linked to deln296 mutation.

Tau phosphorylation has been examined by immunohistochemistry in the brain of a patient affected with familial tauopathy with progressive supranuclear palsy-like phenotype linked to the delN296 mutation in the tau gene. Phospho-specific tau antibodies Thr181, Ser202, Ser214, Ser396 and Ser422, and antibodies to glycogen synthase kinase-3alpha/beta (GSK-3alpha/beta) and to phosphorylated (P) mitogen-activated protein kinase/extracellular signal-regulated kinases (MAPK/ERK), stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK), p38 kinase (p38) and GSK-3betaSer9 have been used to gain understanding of the identification of phosphorylation sites, as well as of the specific kinases that regulate tau phosphorylation at those specific sites, in a familial tauopathy. The neuropathological examination disclosed atrophy of the right precentral gyrus and the brainstem. Neurone loss and gliosis were observed in the substantia nigra, several nuclei of the brainstem and diencephalon. Hyper-phosphorylated tau accumulated in neurones with neurofibrillary tangles and in neurones with pretangles in the substantia nigra, locus ceruleus, peri-aqueductal grey matter, reticular formation, motor nuclei of the brainstem, and thalamus, amygdala and hippocampus. tau-immunoreactive astrocytes and, particularly, oligodendrocytes with coiled bodies were widespread in the brainstem, diencephalons, cerebral white matter and cerebral cortex. Increased expression of MAPK/ERK-P, SAPK/JNK-P, p-38-P and GSK-3beta-P was observed in select subpopulations of neurones with neurofibrillary tangles and in neurones with pretangles. MAPK/ERK-P, SAPK/JNK-P, p38-P and GSK-3beta-P were also expressed in tau-containing astrocytes and in oligodendrocytes with coiled bodies. These findings show, for the first time, activation of precise kinases that regulate tau phosphorylation at specific sites in familial tauopathy.

Adult↗

PubMed2003

Caspase-dependent and caspase-independent signalling of apoptosis in the penumbra following middle cerebral artery occlusion in the adult rat.

Transient focal ischaemia by middle cerebral artery occlusion (MCAO) may produce cell death, but the mechanisms leading to cell death differ in the infarct core and in the penumbra, the immediate zone surrounding the infarct core. In the present study, transient focal ischaemia to adult rats was produced by intraluminal occlusion of the middle cerebral artery for 1 h followed by 0 h (n=6), 1 h (n=10), 4 h (n=8), 6 h (n=2) and 12 h (n=3) of reperfusion. The present model of ischaemia causes a large cortico-striatal infarct extending through the mediolateral cortex and dorsolateral striatum at 12 h. The expression and subcellular distribution of several proteins involved in apoptosis have been examined in the penumbra and in the infarct core by using combined methods of immunohistochemistry, cell subfractionation and Western blotting. Transient focal ischaemia by MCAO results in activation of complex signal pathways for cell death in the penumbra. Increased expression of Bcl-2 and Bax, but not of Bcl-x, occurs in the penumbra at the time when Bax translocates from the cytosol to the mitochondria, cytochrome c is released to the cytoplasm and active caspase-3 is expressed. Bax translocation, cytochrome c release and active caspase-3 are observed at 4 h, but not at 1 h, following reperfusion, and together indicate activation of the caspase-dependent pathway of apoptosis in the penumbra. In contrast, reduced Bax expression but not Bax translocation and cytochrome c release occurs in the infarct core, thus suggesting apoptosis signals restricted to the penumbra. In addition, increased expression of an apoptosis-inducing factor in the cytoplasm and nuclei of selected cells shows, for the first time, activation of the caspase-independent mitochondrial pathway in the penumbra following transient focal ischaemia and reperfusion.

Animals↗

PubMed2003

Phosphorylated protein kinases associated with neuronal and glial tau deposits in argyrophilic grain disease.

Tau phosphorylation was examined in argyrophilic grain disease (AGD) by using the phosphospecific tau antibodies Thr181, Ser202, Ser214, Ser 396 and Ser422, and antibodies to non-phosphorylated and phosphorylated mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases (ERK), stress-activated kinase (SAPK), c-Jun N-terminal kinase (JNK), p38 kinase (p-38), alpha-calcium/calmodulin-dependent kinase II (alphaCaM kinase II), and glycogen synthase kinase-3 (GSK-3), all of which regulate phosphorylation at specific sites of tau. This is the first study in which the role of protein kinases in tau phosphorylation has been examined in AGD. Hyperphosphorylated tau accumulated in grains and pre-tangles in the hippocampus, dentate gyrus, entorhinal and trans-entorhinal cortices, and amygdala in all cases. Ballooned neurons in the amygdala, entorhinal, insular and cingulate cortex, and claustrum contained alphaB-crystallyn and phosphorylated neurofilament epitopes. Some astrocytes and scattered oligodendrocytes containing coiled bodies were recognized with anti-tau antibodies. A few tangles were observed in the entorhinal cortex and hippocampus corresponding to Alzheimer's disease (AD) stages I-III of Braak and Braak. None of the present cases was associated with progressive supranuclear palsy or with alpha-synuclein pathology. Two bands of phospho-tau of 64 and 68 kDa were observed in Western blots of sarkosyl-insoluble fractions enriched with abnormal filaments in AGD, a pattern that contrasts with the 4-band pattern obtained in AD. No modifications in the expression of non-phosphorylated MEK-1, ERK2 and GSK-3alpha/beta, as revealed by immunohistochemistry, were seen in AGD, but sarkosyl-insoluble fractions were particularly enriched in JNK-1 and alphaCaM kinase II. Increased expression of the phosphorylated (P) forms of MAPK/ERK, SAPK/JNK, p38 and GSK-3beta was found in grains and tau-containing cells in AGD. MAPK/ERK-P immunoreactivity was observed in pre-tangles and, diffusely, in the cytoplasm of ballooned neurons, but not in grains. Strong SAPK/JNK-P and P38-P, and moderate GSK-3b-P immunoreactivities selectively occured in grains, in neurons with pre-tangles and in the peripheral region of the cytoplasm of ballooned neurons. MAPK/ERK-P, SAPK/JNK-P, p38-P and GSK-3beta-P were expressed in tau-containing astrocytes and in oligodendrocytes with coiled bodies. Western blots revealed kinase expression in sarkosyl-insoluble fractions but none of the phospho-kinase antibodies recognized hyper-phosphorylated tau protein. These findings indicate complex, specific profiles of tau phosphorylation and concomitant activation of precise kinases that have the capacity to phosphorylate tau at specific sites in AGD. These kinases co-localize abnormal tau in selected structures and cells, including neurons with pre-tangles, ballooned neurons, astrocytes and oligodendrocytes. Most of these kinases are involved in cell death and cell survival in certain experimental paradigms. However, double-labeling studies with the method of in situ end-labeling of nuclear DNA fragmentation and cleaved (active) caspase-3 immunohistochemistry show no expression of apoptosis and death markers in cells bearing phosphorylated kinases.

Aged↗

PubMed2003

An anaplastic astrocytoma (optic chiasmatic-hypothalamic glioma) in a dog.

A tumor located in the optic nerve extended through the optic chiasm, involving the hypophysis and the hypothalamic area in a 3.5-year-old male Boxer dog. It showed a biphasic pattern in which numerous highly fibrillated, well-differentiated pilocytic areas were intermingled with pleomorphic, microcystic tumor tissue. Immunohistochemical analysis of the tumor revealed that most of the neoplastic cells were immunoreactive for S-100 protein, with less intensity for glial fibrillary acidic protein (GFAP) and vimentin. A diagnosis of anaplastic astrocytoma was made on the basis of the histopathologic findings and immunohistochemical results. Moreover, there were similarities with the malignant variant of pilocytic astrocytoma described in human adults as an optic chiasmatic-hypothalamic glioma.

Animals↗

PubMed2002

Anti-tau phospho-specific Ser262 antibody recognizes a variety of abnormal hyper-phosphorylated tau deposits in tauopathies including Pick bodies and argyrophilic grains.

The rabbit polyclonal anti-tau phospho-specific Ser262 antibody (577814 Calbiochem) recognizes disease-specific band patterns on Western blots of sarkosyl-insoluble fractions in Alzheimer's disease (AD), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), argyrophilic grain disease (AGD) and Pick's disease (PiD): four bands of 74/72, 68, 64 and 60 kDa in AD, two bands of 68 and 64 kDa in PSP, CBD and AGD, and two bands of 64 and 60 kDa in PiD. Moreover, anti-tau phospho-specific Ser262 decorates neurons with neurofibrillary tangles, neurons with pre-tangles, dystrophic neurites of senile plaques, neuropil threads, Pick bodies, argyrophilic grains, and coiled bodies. Achromatic neurons in CBD, ballooned neurons in AGD, tufted astrocytes in PSP, astrocytic plaques in CBD and tau-containing astrocytes in AGD are not immunostained with the anti-tau phospho-specific Ser262 antibody. The lack of phospho-specific Ser262 immunoreactivity in tau-containing inclusions in astrocytes suggests different kinase equipment and activation in comparing neurons and astrocytes in tauopathies. Pick bodies in PiD and grains in AGD are weakly, or not all, immunostained in tissue samples with long post-mortem delays, although Ser262 is preserved in brain homogenates corresponding to the same time points processed for Western blot. This indicates postmortem modifications of tau in Pick bodies and argyrophilic grains, but not in other tau-containing inclusions, including paired helical filaments and coiled bodies, and suggests differences in tau conformation, particularly that involving phospho-tau Ser262 among tauopathies. However, it is important to note that phosphorylation of tau at Ser262 does occur in Pick bodies and argyrophilic grains, and this may have important consequences in reducing the capacity of binding phospho-tau to microtubules in these inclusions.

Aged↗

PubMed2002

Intranuclear inclusions, neuronal loss and CAG mosaicism in two patients with Machado-Joseph disease.

UNLABELLED: The presence of neuronal intranuclear inclusions (NIIs) and neuronal mosaicism has been described in some autosomal dominant spinocerebellar ataxias (SCA), but their implication in neurodegenerative mechanisms still remains unclear. OBJECTIVE: To investigate the correlation between neuronal loss and NIIs, and the size of CAG triplet expansion in selected areas of the CNS in two SCA3 patients. MATERIAL AND METHODS: Postmortem neuropathological study was carried out, and the regional distribution of neuronal loss was compared with NIIs. CAG expansion was analysed by PCR amplification in the same regions. RESULTS: Marked neuronal loss was seen in the anterior horn of the spinal cord, pontine nuclei and motor nuclei of the brain stem. Moderate neurone loss was found in the locus ceruleus, colliculus and substantia nigra. Loss of granule and Purkinje cells was found in the cerebellum, mainly in the vermis. NIIs were present in neurones of the involved nuclei of the anterior horn of the spinal cord, medulla oblongata and pons, but not in the locus ceruleus, substantia nigra and cerebellum. A few NIIs were found in the striatum. The number of CAG repeats was 27/70 in the first patient and 21/74 in the second patient. The variation of the expanded allele size among different cerebral areas was +/-1-3 CAG repeats. CONCLUSION: The partial correlation between neuronal loss and NIIs suggests that other factors distinct from NII formation may be involved in the neuronal death. Moreover, the low degree of mosaicism between regions without neuronal loss and regions with marked neuronal loss points to the existence of selective cellular vulnerability to the genetic defect.

Aged↗

PubMed2002

Glycogen synthase kinase-3 is associated with neuronal and glial hyperphosphorylated tau deposits in Alzheimer's disease, Pick's disease, progressive supranuclear palsy and corticobasal degeneration.

Tau phosphorylation was examined in Alzheimer's disease (AD), Pick's disease (PiD), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD) using phospho-specific tau antibodies recognizing the phosphorylated form of Ser202, Ser214 and Ser 396, and antibodies to non-phosphorylated glycogen synthase kinase-3alpha/beta (GSK-3alpha/beta), which regulates phosphorylation at these specific sites on tau and phosphorylated GSK-3betaSer9 (GSK-3beta-P); this antibody is directed to the inactive form of GSK-3beta. Phospho-specific tau antibodies recognized disease-specific band patterns on Western blots of sarcosyl-insoluble fractions: four bands of 73, 68, 64 and 60 kDa in AD, two bands of 68 and 64 kDa in PSP and CBD, and two bands of 64 and 60 kDa in PiD. Moreover, anti-phospho-tau Ser202, Ser214 and Ser369 decorated neurons with neurofibrillary tangles, dystrophic neurites of senile plaques, neuropil threads, Pick bodies, astrocytes and oligodendrocytes with coiled bodies. No differences in the expression of GSK-3alpha/beta were seen between neurons with and without neurofibrillary tangles. GSK-3alpha/beta was enriched in sarcosyl-insoluble fractions, suggesting association of this kinase with tau hyperphosphorylation. In addition, strong expression of the phosphorylated form of GSK-3beta was found in a subpopulation of neurons with neurofibrillary tangles, and in dystrophic neurites of senile plaques, neuropil threads, Pick bodies, tau-containing astrocytes and coiled bodies in AD, PiD, PSP and CBD. This was not due to cross-reactivity between GSK-3 and phospho-tau. Specific bands differing from those of phospho-tau were seen on Western blots of sarcosyl-insoluble fractions processed for GSK-3alpha/beta and GSK-3beta-P. Double-labeling immunohistochemistry discloses that GSK-3beta-P co-localizes with abnormal tau in about 50% of neurons with neurofibrillary tangles, and in neuronal processes, astrocytes and oligodendrocytes in various tauopathies. The present results support a pivotal role for GSK-3 in tau phosphorylation in neurons and glial cells. Moreover, the elevated number of tau-containing cells stained with anti-GSK-3beta-P antibodies suggests a partial inactivation of the kinase, or sequestration of the phosphorylated form, which may contribute to the regulation of the cascade of tau hyperphosphorylation in tauopathies, and to protect tau-containing cells from apoptosis.

Aged↗

PubMed2002

Caspase-3-associated apoptotic cell death in excitotoxic necrosis of the entorhinal cortex following intraperitoneal injection of kainic acid in the rat.

The present study is directed to study: (a) bax translocation and cytochrome c release as mediators of the mitochondrial pathway of apoptosis; (b) Fas-L (Fas-ligand) expression as an indicator of the possible involvement of the Fas/Fas-L signaling pathway; and (c) active caspase-3 expression as the main executioner of caspase-mediated apoptosis, in rats receiving an intraperitoneal injection of the glutamate analogue kainic acid (KA) at a dose of 9 mg/kg, which is sufficient to produce generalized seizures and excitotoxic cell death in the entorhinal cortex. Sub-fractionation studies of entorhinal cortex homogenates have shown cytochrome c and cytochrome oxidase IV localized in the mitochondrial fraction, and Bax localized in the cytosolic fraction. No modifications in the sub-cellular distribution of cytochrome c and Bax have been observed at 6 h and 24 h in KA-treated rats. Morphological studies have shown cytoplasmic shrinkage and nuclear condensation consistent with necrosis in the entorhinal cortex. Many neurons (about 30% of dying cells) are stained with the method of in situ end-labeling of nuclear DNA fragmentation. Yet only about 5% of dying cells have apoptotic morphology. A percentage of dying cells (5% at 6 h and 40% at 24 h) over-express Fas-L but only about 2% of dying cells at 24 h post-injection express cleaved caspase-3 (17 kD). The present data further support the concept that necrosis is the predominant form of cell death in the entorhinal cortex, although caspase-3-dependent apoptotic cell death may play a limited role, in the present paradigm of KA-induced excitotoxicity.

Animals↗

PubMed2002

Overexpression of semicarbazide sensitive amine oxidase in the cerebral blood vessels in patients with Alzheimer's disease and cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy.

Semicarbazide sensitive amine oxidase (SSAO) metabolizes oxidative deamination of primary aromatic and aliphatic amines, and, in the brain, it is selectively expressed in blood vessels. SSAO expression is examined, by immunohistochemistry with a purified polyclonal antibody to SSAO from bovine lung, in the brains of subjects with Alzheimer disease (AD; n=10), cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL; n=2), and age-matched controls (n=8). SSAO immunoreactivity is restricted to meningeal and parenchymal blood vessels in control and diseased brains. Yet, a marked and selective increase in SSAO immunoreactivity occurs in association with betaA4 vascular amyloid deposits in patients with AD, and in the vicinity of the typical granular deposits in the blood vessels of gray and white matter in patients with CADASIL. Oxidative deamination of primary aromatic and aliphatic amines by SSAO produces ammonia, hydrogen peroxide and the corresponding aldehyde. Moreover, increased SSAO immunoreactivity is associated with increased Cu/Zn superoxide dismutase 1 expression restricted to abnormal blood vessels in diseased brains. Therefore, it is suggested that increased SSAO expression is a source of oxidative stress in the blood vessel wall in AD and CADASIL.

Aged↗

PubMed2002

Abnormal synaptic protein expression and cell death in murine scrapie.

Reduced expression of synaptophysin p38, synaptic-associated protein of molecular weight 25,000 (SNAP-25), syntaxin-1, synapsin-1, and alpha- and beta-synuclein, matching the distribution of spongiform degeneration, was found in the neurological phase of scrapie-infected mice. In addition, synaptophysin and SNAP-25 were accumulated in isolated neurons, mainly in the thalamus, midbrain and pons, and granular deposits of alpha- and beta-synuclein were present in the neuropil of the same areas. No modifications in the steady state levels of Bcl-2, Bax, Fas and Fas ligand were observed following infection. Yet antibodies against the c-Jun N-terminal peptide, which cross-react with products emerging after caspase-mediate proteolysis, recognize coarse granular deposits in the cytoplasm of reactive microglia. In situ end-labeling of nuclear DNA fragmentation showed positive nuclei with extreme chromatin condensation in the thalamus, pons, hippocampus and, in particular, the granular layer of the cerebellum. More importantly, expression of cleaved caspase-3, a major executioner of apoptosis, was seen in a few cells in the same regions, thus indicating that cell death by apoptosis in scrapie-infected mice is associated with caspase-3 activation. The present findings support the concept that synaptic pathology is a major substrate of neurological impairment and that caspase-3 activation may play a pivotal role in apoptosis in experimental scrapie. However, there is no correlation between decreased synaptic protein expression and caspase-3-associated apoptosis, which suggests that in addition to abnormal prion protein deposition, there may be other factors that distinctively influence synaptic vulnerability and cell death in murine scrapie.

Animals↗

PubMed2002

Active, phosphorylation-dependent MAP kinases, MAPK/ERK, SAPK/JNK and p38, and specific transcription factor substrates are differentially expressed following systemic administration of kainic acid to the adult rat.

Excitotoxicity is considered a major cell death inductor in neurodegeneration. Yet the mechanisms involved in cell death and cell survival following excitotoxic insults are poorly understood. Expression of active, phosphorylation-dependent mitogen-activated extracellular signal-regulated kinases (MAPK/ERKs), stress-activated c-Jun N-terminal kinases (SAPK/JNKs) and p38 kinases, as well as their putative active, phosphorylation-dependent specific transcriptional factor substrates CREB, Elk-1, ATF-2, c-Myc and c-Jun, has been examined following systemic administration of kainic acid (KA) at convulsant doses to rats. Increased phosphorylated MAPK (MAPK(P)) immunoreactivity has been found at 3 and 6 h in the vulnerable regions entorhinal cortex and CA3, in which neurons are committed to die, as well as in sensitive regions dentate gyrus and gyrus cinguli, in which neurons will survive. JNK(P) has been observed in the entorhinal cortex and dentate gyrus, and p38(P) immunoreactivity occurs in the entorhinal cortex. Strong c-Myc(P) expression parallels MAPK(P) immunoreactivity in the entorhinal cortex, CA3, dentate gyrus and gyrus cinguli, showing that enhanced c-Myc(P) expression does not preclude cell death or cell survival. Selective decrease of CREB(P) immunoreactivity in entorhinal cortex and CA3 indicates CREB(P) reduction associated with cell death. Strong c-Jun(P) immunoreactivity has been found in the entorhinal cortex, CA3 and dentate gyrus, thus suggesting that regulation of two opposing cellular programs (cell death or cell survival) of c-Jun(P) depends on c-Jun interactions with other factors. Interestingly, ATF-2(P), and to a lesser extent Elk-1(P), is selectively increased in the dentate gyrus. These results suggest ATF-2(P) involvement in cell survival of dentate gyrus granule cells. The present results demonstrate activation of specific MAPK pathways in association with either cell death or cell survival triggered by KA. Furthermore, increased Ras activation, as seen with p21 Ras activation assay, indicates a crucial role for Ras in activating MAP kinases following excitotoxic insult.

Activating Transcription Factor 2↗

PubMed2002

Early induction of secretoneurin expression following kainic acid administration at convulsant doses in the rat and gerbil hippocampus.

The expression of secretogranin-II and its major proteolytic product secretoneurin (SN) is under the control of neuronal excitation, as demonstrated by treating rats with the excitotoxic kainic acid (KA). Differences in the structure and function of the hippocampus in rats and gerbils have been described; these suggest possible differential reactive responses to KA. In the present study, the SN immunostaining pattern in relation with cell damage is analyzed from 6 h to 4 days following KA administration in rats and gerbils. Dramatic differences in the expression of SN were found in the hippocampal complex following KA administration in gerbils and rats. A robust increase in SN immunoreactivity was detected in the pyramidal cell layer of the rat hippocampus, especially in the CA1 area. In the gerbil, however, a strong increase in SN immunostaining was detected in interneurons of the hippocampal formation, as shown by double-labeling immunohistochemistry to SN and the calcium-binding proteins parvalbumin, calbindin, and calretinin. In addition, no damage (in the hippocampal formation) or moderate damage (in the entorhinal cortex) was observed in the gerbil, in contrast to the rat. The administration of KA and the GABA-B receptor inhibitors (CGP56999A or CGP36742) to the gerbil resulted in a strong rise in SN immunoreactitivty in the CA1 pyramidal cell layer of the hippocampus, as in the rat. However, no increased cell damage was observed under these conditions. The present data provide evidence of a species-differential reactive response to KA that might be based, in part, on distinct inhibitory intrahippocampal circuitry.

Animals↗

PubMed2002

CDP-choline reduces pro-caspase and cleaved caspase-3 expression, nuclear DNA fragmentation, and specific PARP-cleaved products of caspase activation following middle cerebral artery occlusion in the rat.

Citicoline has been demonstrated to be beneficial in several models of cerebral ischaemia. We tested the hypothesis that citicoline may provide apoptotic pathways following focal cerebral ischaemia. Focal cerebral ischaemia was produced by distal, permanent middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats. The animals were randomised into four groups: (B+A) Citicoline 500 mg/kg IP 24 and 1 h before MCAO, and 23 h after MCAO; (A) citicoline 500 mg/kg IP, within 30 min after MCAO, and 23 h after MCAO; (C) vehicle IP; and (D) sham-operated. The animals were sacrificed at 12 h (n=8 per group) and 24 h (n=8 per group) after MCAO. Immunohistochemistry was performed on free-floating tissue sections with goat polyclonal antibodies to procaspase-1, -2, -3, -6 and -8, and in paraffin-embedded sections processed for cleaved caspase-3 (17 kDa) immunohistochemistry. Finally, some sections were stained with the method of in situ end-labelling of nuclear DNA fragmentation. For gel electrophoresis and Western blotting, antibodies to poly (ADP-ribose) polymerase (PARP) products of 89 kDa were used to reveal specific cleavage substrates of caspases. MCAO induced the expression of all procaspases and the expression of PARP products of 89 kDa, as well as cells with nuclear DNA fragmentation, at 12 and 24 h, in the infarcted core and penumbra. Citicoline reduced the expression of all procaspases at 12 and 24 h after MCAO, as well as the expression of cleaved caspase-3 in cells in the penumbra area. This was accompanied by a reduction in the number of cells bearing nuclear DNA fragments. The expression of caspase-cleaved products of PARP (PARP 89 kDa) was reduced in citicoline-treated ischaemic rats. These results show that citicoline inhibits the expression of proteins involved in apoptosis following MCAO.

Animals↗