Shoichi Katsuragi

Identification of monocyte chemoattractant protein-1 in senile plaques and reactive microglia of Alzheimer's disease

Abstract It has been shown that human monocytes express monocyte chemoattractant protein‐1 (MCP‐1), an inflammatry factor, in response to non‐fibrillar β‐amyloid protein. Reactive microglia and inflammatory factors were reported to be present in β‐amyloid deposits (senile plaques) in Alzheimers disease, suggesting the presence of MCP‐1 in senile plaques. To address this issue, we examined MCP‐1‐immunoreactivity in senile plaques using a mouse monoclonal anti‐MCP‐1 antibody. Monocyte chemoattractant protein‐1 was found immunohistochemically in mature senile plaques and reactive microglia but not in immature senile plaques of brain tissues from five patients with Alzheimers disease. These findings suggest that MCP‐1‐related inflammatory events induced by reactive microglia contribute to the maturation of senile plaques.

Ultrastructural studies of amyloid fibrils and senile plaques in human brain.

SummaryAmyloid fibrils and senile plaques in brains with Alzheimers disease, senile dementia and Downs syndrome were examined by light and electron microscopy. In addition, replicas of amyloid fibrils, made by a quick freezing method from a brain with Downs syndrome, were examined. All amyloid masses forming the cores of senile plaques consisted of numerous amyloid fibrils spreading from the walls of small blood vessels to the surrounding parenchyma. The amyloid fibrils ran in various directions, forming bundle-like groups in a geometrical array. They appeared as rods with hollow structures consisting of an array of globular units in the replicas, while they showed bead-like structure in the tissue specimens of 500-nm thick sections. The ultrastructure of replicas reveals a new finding on the structure of amyloid fibrils in the human brain.

Nuclear Localization of the δ Subunit of Ca2+/Calmodulin-Dependent Protein Kinase II in Rat Cerebellar Granule Cells

Abstract : To examine the physiological roles of the δ subunit of Ca2+/calmodulin‐dependent protein kinase ∥ (CaM kinase ∥δ) in brain, we examined the localization of CaM kinase ∥δ in the rat brain. A specific antibody to CaM kinase ∥δ1‐δ4 isoforms was prepared by immunizing rabbits with a synthesized peptide corresponding to the unique carboxyl‐terminal end of these isoforms. The prepared antibody did not recognize the α, β, and γ subunits, which were each overexpressed in NG108‐15 cells. Immunoblot analysis on various regions and the nuclear fractions from rat brains suggested that some isoforms of CaM kinase ∥δ1‐δ4 were abundant in the nucleus in the cerebellum. Total RNA from the cerebellum was analyzed by RT‐PCR with a primer pair from variable domain 1 to variable domain 2. We detected the three PCR products δ3.1, δ3.4, and δ3 that contained the nuclear localization signal. These CaM kinase ∥δ3 isoforms were localized in the nuclei in transfected NG108‐15 cells. Immunohistochemical study suggested the existence of these isoforms in the nuclei in cerebellar granule cells. These results suggest that CaM kinase ∥δ3 isoforms are involved in nuclear Ca2+ signaling in cerebellar granule cells.

A Novel Localized Amyloidosis Associated with Lactoferrin in the Cornea

We report a novel localized amyloidosis associated with lactoferrin. To elucidate the precursor protein of corneal amyloidosis associated with trichiasis, we analyzed amyloid deposits from three patients by histopathology and biochemistry. Amyloid deposits showed immunoreactivity, confirmed by electron microscopy, for only anti-human lactoferrin antibody. Electrophoresis of amyloid fibrils revealed lactoferrin with and without sugar chains; N-terminal sequence analysis revealed full-length lactoferrin and a truncated tripeptide of N-terminal amino acids, Gly-Arg-Arg. Carboxymethylated wild-type lactoferrin formed amyloid fibrils in vitro. Lactoferrin gene analysis in the three patients revealed a Glu561Asp mutation in all of the patients and a compound heterozygote of Ala11Thr and Glu561Asp mutations in one patient. A heterozygotic Glu561Asp mutation appeared in 44.8% of healthy Japanese volunteers, suggesting that the mutation may not be an essential mutation for amyloid formation (p = 0.104). Results thus suggest that lactoferrin is this precursor protein.

Morphological study of amyloid fibrils and preamyloid deposits in the brain with alzheimer's disease

SummaryIn addition to the ultrastructural study of amyloid fibrils, amyloid fibrils and preamyloid in the brain which had the fine ultrastructure of a well-preserved neuropil were examined using methenamine silver stain by light and electron microscope. In serial sections, amyloid fibrils in extracellular spaces continued directly to the capillaries. Using methenamine silver stain, silver granules were deposited at the amyloid fibrils and in extracellular spaces forming diffuse plaques. Many silver granules in the extracellular spaces seemed to stain preamyloid surrounding the capillaries. These findings to indicate that the capillaries have an important role in the formation of amyloid fibrils at least in some senile plaques.

Immunohistochemical examination of phosphorylated tau in granulovacuolar degeneration granules

Abstract Granulovacuolar degeneration (GVD) and neurofibrillary tangles (NFT) are neuropathological features in Alzheimers disease (AD). The molecular mechanism of GVD formation remains unknown. Recent immunohistochemical investigations suggested a potential link of NFT to GVD formation. Enzyme histochemical studies and electronmicroscopic findings suggested that GVD is formed through lysosomal autophagy of intraneuronal substances. We recently demonstrated that in non‐demented cases NFT was phosphorylated at serines 199, 202 and 422 in paired helical filament (PHF)‐tau more than in serine 396, while NFT in AD cases was similarly phosphorylated at these four sites in tau. In this study, we demonstrated immunohistochemically a similar phosphorylation state of tau in GVD granules to that in NFT in both non‐demented cases and AD patients by using a mouse monoclonal anti‐tau antibody and three phosphorylation site‐specific antibodies for PHF‐tau, indicating that GVD granules and NFT are composed of similar phosphorylated‐tau. However, we could not detect PHF structures within any GVD using electronmicros‐copy, indicating that PHF itself is not phagocytized by lysosomes during GVD formation. Therefore, the source of GVD granules might be phosphorylated pre‐PHF‐tau.

Wilson's Disease with Extensive Degeneration of Cerebral White Matter and Cortex

Abstract: This is a report of an autopsy case of Wilsons disease with widespread degeneration of the cerebral cortex and white matter, the basal ganglia and thalamus and, to a lesser degree, the cerebellum and brain stem. The patient was a 28‐year‐old man at the time of death with the clinical course of a 20‐year duration.

Ultrastructural Changes of Blood Vessels in the Cerebral Cortex in Alzheimer's Disease

Abstract: Several parts of the cerebral cortices in five brains from patientswith Alzheimers disease were examined by light and electron microscopes. The results obtained are as follows:

Late onset X‐linked hydrocephalus with normal cerebrospinal fluid pressure

Abstract A family with X‐linked hydrocephalus with normal cerebrospinal fluid (CSF) pressure and in which three brothers and a grandson of case 1, a proband, were affected is reported. The symptoms at onset were epileptic attacks that started in adulthood in the three brothers and at the age of 6 years in the grandson. In the three brothers, from 10 to 27 years after the onset of epileptic episodes, disorganization of intelligence and psychiatric deterioration were gradually noticed by their families. At the same time, they showed occasional urinary incontinence. Brain computed tomography (CT) scans revealed dilatation of the ventricular systems. Based on the results of the measurement of CSF pressure and radioactive‐iodinated human serum albumin (RISA)‐cysternography, two of the brothers were diagnosed as having normal pressure hydrocephalus (NPH), and they were treated neurosurgically. However, no obvious improvement in clinical symptoms was observed. Although the grandson had shown normal psychomotor development during his early childhood, temporal epilepsy and temper tantrums started at the age of 6 years. Computed tomography‐scanning revealed dilatation of the ventricular system similar to the other three cases at the age of 8 years. With the diagnosis of NPH, the patient underwent a shunt operation, which resulted in no obvious effects. As it is reasonable to surmise that the pathological gene would have been transferred via the daughter of the proband to the grandson, it is suggested that the inheritance manner might be X‐linked recessive. The cases presented here are different from the cases of hydrocephalus due to stenosis of the aqueduct Sylvius (HSAS) and other types of X‐linked hydrocephalus reported previously in terms of the age of onset, course, symptoms, and CT findings. Thus, it is suggested that the present cases might be a new type of X‐linked hydrocephalus.

A Novel Tool for Detecting Amyloid Deposits in Systemic Amyloidosis in Vitro and in Vivo

We synthesized (trans,trans)-1-bromo-2,5-bis-(3-hydroxycarbonyl-4-hydroxy)styrylbenzene (BSB) and used this compound to detect amyloid fibrils in autopsy and biopsy samples from patients with localized amyloidosis, such as familial prion disease, and systemic amyloidosis, such as familial amyloidotic polyneuropathy, amyloid A (AA) amyloidosis, light chain (AL) amyloidosis, and dialysis-related amyloidosis. BSB showed reactions in all Congo red-positive and immunoreactive regions of the samples examined in the study, and some amyloid fibrils in the tissues could be detected more precisely with BSB than with the other methods. In the mouse model of AA amyloidosis, injected BSB reacted with amyloid in all regions in the serial sections in which Congo red staining was positive. A highly sensitive 27-MHz quartz crystal microbalance analysis revealed that BSB showed a significant affinity for amyloid fibrils purified from familial amyloidotic polyneuropathy and dialysis-related amyloidosis samples and suppressed formation of transthyretin amyloid in vitro. These results suggest that BSB may become a valuable tool for detection of amyloid deposits in amyloidosis and of the mechanism of amyloid formation.