Nam-Ho Choi-Miura

SP-40,40 is a constituent of Alzheimer's amyloid

SummaryCerebrospinal fluid (CSF), serum and seminal plasma contain a small amount of SP-40,40, a modulatory protein of the human complement system. The SP-40,40 in each body fluid was different in molecular size on SDS-PAGE, and glioblastoma cells, hepatoma cells and testicular tumor cells produced SP-40,40, while neuroblastoma cells did not. Therefore, it was estimated that CSF SP-40,40 originated in glia cells, serum SP-40,40 in liver cells and seminal plasma SP-40,40 in testicular cells. SP-40,40 concentrations in CSF of the patients with Alzheimers disease and the patients with cerebral tumor were higher than those of normal donors. β-Amyloid deposits in the brains of the patients with Alzheimers disease were stained with an anti-SP-40,40 monoclonal antibody (mAb) but not with an anti-S-protein mAb, while cellular processes around β-amyloid were stained with an anti-S-protein mAb but not with an anti-SP-40,40 mAb. Therefore, β-amyloid contained SP-40,40 in a form different from that in the soluble membrane attack complex (SMAC, SC5b-9) of the complement, which contains S-protein as well as SP-40,40.

Distribution and Synthesis of Apolipoprotein J in the Atherosclerotic Aorta

The distribution of apolipoprotein (apo) J during the development of atherosclerosis in the human aorta was evaluated by immununohistochemical observation, together with the other apolipoprotein A-I, A-II, B, C-III, and E. Although apoJ was never observed in the normal aorta (ie, without any intimal lesions or intimal thickening), it was distributed not only in the intima but also in the media of aortas with diffuse, intimal thickening or atherosclerotic lesions. Double immunostaining with antibodies for apoJ and alpha-smooth muscle actin revealed apoJ deposition in smooth muscle cells (SMCs) or the aortic stroma in the vicinity of SMCs. The extent of apoJ distribution in the aortic wall increased with the degree of atherosclerosis development. In addition, the distribution pattern of apoJ was very similar to that of apoA-I and E. In situ hybridization with human apoJ cDNA demonstrated intense signals in cells scattered within the subendothelial space and medial SMCs of the aorta with advanced atherosclerosis but not in those of the normal aorta without intimal thickening. Furthermore, reverse transcriptase-polymerase chain reaction of the cultured human aortic SMCs revealed apoJ mRNA expression in these cells. The results indicate that apoJ in the aortic wall originates from not only apoJ circulated in the plasma but also apoJ produced by SMCs in the aortic wall. Considering the similarities of the distribution between apoJ and apo-A-I or E, we hypothesize that apoJ possibly has a protective role against human atherosclerosis by its involvement with cholesterol transport from the aortic wall to the liver.

Complete cerebral ischemia with short-term survival in rat induced by cardiac arrest. II: Extracellular and intracellular accumulation of apolipoproteins E and J in the brain

The distribution of apolipoprotein E (apo E) and apolipoprotein J (apo J) was investigated immunocytochemically in rats at various time intervals after 10 min global cerebral ischemia (GCI) induced by cardiac arrest. Strong apo E and weaker apo J immunoreactivity was found extracellularly in multiple deposits located close to the microvessels. These deposits appeared 3 h after GCI and were present, but not in all the animals, at all time intervals studied post-GCL. In some rats, apo E immunoreactivity was also found in small necrotic foci. Widespread, neuronal apo E immunostaining appeared 6 h post-GCI. However, the strongest neuronal apo E immunoreactivity was found 7 days post-GCI in those neurons, most often observed in the CA1 hippocampal region, exhibiting signs of ischemic cell damage. These ischemically damaged neurons displayed weaker immunoreactivity to apo J, despite its increase in the response to GCI in the various brain regions examined. Our data show that mechanisms operating in ischemia are able to supply large amounts of apo E and apo J to the brain tissue and suggest involvement of both apo E and apo J in a complex series of events occurring in the ischemic brain. Perivascular deposits of apo E/apo J colocalized with amyloid beta protein precursor epitopes that have been disclosed by us previously in this model. Whether this phenomenon is limited to postischemic brain tissue, or can be encountered also in other pathological conditions will require further elaboration.

Deposition of apolipoproteins E and J in senile plaques is topographically determined in both Alzheimer's disease and Down's syndrome brain

The link between the immunolocalization of apolipoproteins E (apo E) and J (apo J) and the different severity of beta-amyloid deposition in various areas of Alzheimers disease (AD) and Downs syndrome (DS) brain was analyzed. Both apolipoproteins were found in all types of senile plaques (SPs) in the cerebral cortex, which is early and severely involved in beta-amyloidosis, but apo E was seen more often than apo J in diffuse A beta deposits, especially in young DS cases and nondemented elderly persons. In the striatum and cerebellum, which show predominance of diffuse A beta deposits throughout the lifespan, apo J was absent, except for few compact deposits, whereas apo E was more widely distributed, apart from diffuse plaques in the striatum. By immunoelectron microscopy, A beta fibrils were disclosed in diffuse plaques in all brain regions studied, but not all of these early fibrillar deposits, even in the neocortex of young DS cases, showed apo E and apo J labeling. Thus, our data indicate that the immunoreactivity to apo E and J within A beta deposits is topographically determined in both AD and DS brain. Moreover, although it appears that neither of apolipoproteins studied is necessary to initiate A beta fibrillogenesis, disclosed topographic dissimilarities of their distribution within parenchymal A beta deposits suggest that they may be involved in different ways in the pathogenesis of beta-amyloidosis.

Changes in the distribution pattern of gelatin-binding protein of 28 kDa (adiponectin) in myocardial remodelling after ischaemic injury.

Aims:  Gelatin‐binding protein of 28 kDa (GBP28) is a collagen‐like plasma protein having a binding capacity with collagens. We investigated GBP28 role on myocardial remodelling as well as the diagnostic significance of GBP28 immunostaining in myocardial infarction.

Relationship between multifunctional protein "clusterin" and Alzheimer disease.

In the Alzheimer disease (AD) brain, senile plaques contain several proteins and cytokines, such as beta-amyloid protein (A beta), interleukin 1, transforming growth factor beta 1 (TGF beta 1), and apolipoprotein E, which may contribute to the process of neurodegeneration. Clusterin is also known to colocalize with A beta deposits in neuritic plaques. Clusterin is a multifunctional protein that causes cell aggregation, binds to beta-endorphin, and inhibits the terminal complex formation of complement. Clusterin mRNA and protein are increased in the brains of AD patients. Cytokines such as TGF beta 1 and interleukin 1 enhance the expression of clusterin, which may link clusterin to inflammatory mechanisms in AD. A beta, a 39-43 amino acid peptide, is a major component of the senile plaques that are characteristic of AD. Highly aggregated A beta is implicated in neurodegeneration, e.g., A beta aggregates spontaneously into fibrillar forms resembling those in plaques that, in experimental models, cause neurotoxicity through oxidative stress. Clusterin inhibits the aggregation of A beta, which might be neuroprotective according to the aggregation-toxicity hypothesis of A beta. However, clusterin enhanced the oxidative stress of A beta. This may extend its neurotoxicity to locations distal from plaques wherever A beta is present.

Characterization of mouse GBP28 and its induction by exposure to cold

OBJECTIVE: To investigate whether the expression of the novel adipose tissue-specific protein GBP28 in adipose tissue and serum are altered in mice under a variety of conditions.DESIGN: Mice were fed a high-fat diet for 4 weeks, fasted for 48 h or exposed at 4°C.SUBJECTS: C57BL/6J mouse, male, 4–6 weeks old.MEASUREMENTS: GBP28 mRNA, GBP28 protein, blood glucose, insulin and fad pad weight of the mice.RESULTS: We first confirmed that the mouse has GBP28 and its characteristics are the same as human GBP28. Serum concentration and mRNA levels of GBP28 significantly increased in the mice exposed to cold.CONCLUSION: GBP28 may play a role in homeostasis, regulating body temperature and basal metabolic rate in response to changing environmental conditions.

High-density-lipoprotein-independent killing of Trypanosoma brucei by human serum

The cattle pathogen Trypanosoma brucei brucei is morphologically indistinguishable from the human pathogens T.b. rhodesiense and T.b. gambiense. However, unlike the human pathogens, T.b. brucei is lysed by normal human serum (NHS). The trypanolytic factor in NHS co-purifies with high-density lipoproteins (HDL), but its precise nature is unknown. Using a new fluorescence-based viability assay to assess T.b. brucei killing, we find that the HDL-deficient sera from two patients with Tangier disease are as trypanolytic as NHS. Fractionation of the Tangier sera by density ultracentrifugation revealed that the activity resides only in lipoprotein-depleted fractions. Tangier and NHS were also subjected to molecular sieving chromatography, and the activity profiles were identical. Lytic fractions to T. brucei (but not to T. rhodesiense) appeared under two distinct peaks of 100-600 kDa and > 1000 kDa. Neither peak coincided with the position of the major serum lipoproteins, as determined by cholesterol titrations. The high-molecular-mass peak did not contain the HDL-associated apolipoprotein-A1. Further, we did not find that purified apolipoproteins A1 or J are lytic for the trypanosomes. We conclude that the killing of T. brucei by human serum can be independent of HDL.

The novel acute phase protein, IHRP, inhibits actin polymerization and phagocytosis of polymorphonuclear cells

Objective and Design: In the present study, the involvement of the binding of IHRP (inter-alpha-trypsin inhibitor family heavy chain-related protein) and actin in phagocyte activity was investigated.¶Materials and Methods: The actin polymerization and the phagocytic activity of the polymorphonuclear (PMN) cells were studied in the presence of IHRP.¶Results: IHRP inhibited the polymerization of actin and the phagocytic activity of the PMN cells.¶Conclusion: 1) IHRP may bind to actin released from the damaged cells and suppress its toxic action by preventing the formation of actin fibril. 2) IHRP may bind to cell surface actin on PMN cells and inhibit their phagocytic activities. 3) From these results, IHRP may act as an anti-inflamma-tory protein.

Increased expression of vascular endothelial growth factor in placentas of p57Kip2 null embryos

Placentas of mice lacking p57Kip2 expression have trophoblastic hyperplasia. To elucidate the mechanism underlying this phenomenon, we studied expression of two angiogenic factors, vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF). Immunohistochemical analysis with anti‐VEGF antibodies indicated that VEGF expression was stronger and more clearly detectable in placentas of p57Kip2 null embryos compared to wild‐type placentas. PlGF showed no significant differences between placentas of p57Kip2 null and wild‐type embryos. In quantitative analysis, placentas of p57Kip2 null embryos showed higher VEGF messenger (m)RNA and protein levels than did wild‐type placentas. PlGF mRNA and protein levels were not significantly different. These findings suggest that VEGF is involved in the hyperplasia that occurs in placentas of p57Kip2 null embryos.