1/3. 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.- - - - - - - - - - ranking = 1keywords = gliosis (Clic here for more details about this article) |
2/3. Tau-predominant-associated pathology in a sporadic late-onset Hallervorden-Spatz syndrome.Hallervorden-Spatz syndrome (HSS) is a heterogeneous clinicopathological disorder currently included within the broader title of neurodegeneration with brain iron accumulation (NBIA). The classic histological hallmarks of HSS are axonal spheroids and excessive iron-containing granules accompanied by neuronal loss and gliosis in the globus pallidus and substantia nigra reticulata. In the modern literature, attention has been drawn to the co-occurrence of two other histological markers: lewy bodies mainly composed of abnormal alpha-synuclein, and neurofibrillary tangles due to hyperphosphorilated tau aggregation. Discrepancies exist regarding the importance of these molecular changes and its relevance for the nosology of HSS. Most authors have emphasized the importance of the Lewy body-like pathology, favoring the inclusion of HSS within the alpha-synucleinopathies. We report on a case of late-onset HSS, with the typical histological findings restricted to the basal ganglia and cerebellum in which tau pathology was exceedingly more abundant than alpha-synuclein pathology. This case contributes to the increasing evidence about the heterogeneity of HSS. We favor the view that the molecular changes and the protein misfolding underlying the Lewy body and tangle formation in HSS/NBIA are secondary to the main pathological process and should not be taken as the basis for its nosological classification.- - - - - - - - - - ranking = 1keywords = gliosis (Clic here for more details about this article) |
3/3. Sporadic four-repeat tauopathy with frontotemporal degeneration, parkinsonism and motor neuron disease.We report a sporadic tauopathy of 6-year duration in a 76-year-old woman. Her initial symptoms were asymmetrical parkinsonism and muscle weakness, with apraxia appearing 2 years later. The brain showed frontal and temporal cerebral atrophy; severe neuronal loss and gliosis were observed in the precentral cortex (loss of Betz cells was also evident) and premotor area, and in the medial temporal lobe, including the temporal tip, amygdala, and hippocampal CA1-subiculum border zone. The substantia nigra showed moderate neuronal loss and gliosis. In the spinal cord, loss of the anterior horn cells and degeneration of the corticospinal tracts were a characteristic feature. In addition, in the affected regions, the remaining neurons were often found to contain intracytoplasmic inclusions resembling neurofibrillary tangles. Tau immunostaining revealed widespread glial-predominant lesions in the cerebral gray and white matter. In contrast, predominance of neuronal lesions (pretangles/tangles) was a feature in the subcortical gray matter, including the spinal cord. The remaining upper and lower motor neurons were also affected by tau pathology. Accumulated tau in these glial cells and neurons was clearly recognized by a specific antibody against four-repeat (4R) tau. The ultrastructural presence of tau-positive tubular structures was confirmed in the glial cells and neurons (tangles). immunoblotting of a frozen frontal lobe sample revealed accumulation of 4R-predominant tau isoforms. No mutations were found in the tau gene. These findings indicate that a sporadic 4R tauopathy can cause frontotemporal degeneration, parkinsonism, and motor neuron disease. The present case could represent a new clinicopathological phenotype of non-familial tauopathy.- - - - - - - - - - ranking = 2keywords = gliosis (Clic here for more details about this article) |