Homocysteine, another risk factor for Alzheimer disease, impairs apolipoprotein E3 function

Apolipoprotein E (apoE) ε4 and hyperhomocysteinemia are risk factors for Alzheimer disease (AD). The dimerization of apoE3 by disulfide bonds between cysteine residues enhances apoE3 function to generate HDL. Because homocysteine (Hcy) harbors a thiol group, we examined whether Hcy interferes with the dimerization of apoE3 and thereby impairs apoE3 function. We found that Hcy inhibits the dimerization of apoE3 and reduces apoE3-mediated HDL generation to a level similar to that by apoE4, whereas Hcy does not affect apoE4 function. Western blot analysis of cerebrospinal fluid showed that the ratio of apoE3 dimers was significantly lower in the samples from the patients with hyperhomocysteinemia than in those that from control subjects. Hyperhomocysteinemia induced by subcutaneous injection of Hcy to apoE3 knock-in mice decreased the level of the apoE3 dimer in the brain homogenate. Because apoE-HDL plays a role in amyloid β-protein clearance, these results suggest that two different risk factors, apoE4 and hyperhomocysteinemia, may share a common mechanism that accelerates the pathogenesis of AD in terms of reduced HDL generation.     

Preparation of platinum(IV) complexes with dipeptide and diimine. X-ray crystal structure and 195Pt NMR spectra

We prepared platinum(IV) complexes containing dipeptide and diimine or diamine, the [PtCl(dipeptide-N,N,O)(diimine or diamine)]Cl complex, where -N,N,O means dipeptide coordinated as a tridentate chelate, dipeptide=glycylglycine (NH(2)CH(2)CON(-)CH(2)COO(-), digly, where two protons of dipeptide are detached when the dipeptide coordinates to metal ion as a tridentate chelate), glycyl-L-alanine (NH(2)CH(2)CON(-)CHCH(3)COO(-), gly-L-ala), L-alanylglycine (NH(2)CH CH(3)CON(-)CH(2)COO(-), L-alagly), or L-alanyl-L-alanine (NH(2)CHCH(3)CON(-)CHCH(3)COO(-), dil-ala), and diimine or diamine=bipyridine (bpy), ethylenediamine (en), N-methylethylenediamine (N-Me-en), or N,N'-dimethylethylenediamine (N,N'-diMe-en). In the complexes containing gly-L-ala or dil-ala, two separate peaks of the (195)Pt NMR spectra of the [PtCl(dipeptide-N,N,O)(diimine or diamine)]Cl complexes appeared in, but in the complexes containing digly or L-alagly, one peak which contained two overlapped signals appeared. One of the two complexes containing gly-L-ala and bpy, [PtCl(gly-L-ala-N,N,O)(bpy)]NO(3), crystallized and was analyzed. This complex has the monoclinic space group P2(1)2(1)2(1) with unit cell dimensions of a=9.7906(3)A, b=11.1847(2)A, c=16.6796(2)A, Z=4. The crystal data revealed that this [PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) complex has the near- (Cl, CH(3)) configuration of two possible isomers. Based on elemental analysis, the other complex must have the near- (Cl, CH(3))-[PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) configuration. The (195)Pt NMR chemical shifts of the near- (Cl, CH(3))-[PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) complex and the far- (Cl, CH(3))-[PtCl(gly-L-ala-N,N,O)(bpy)]NO(3) complex are 0 ppm and -19 ppm, respectively (0 ppm for the Na(2)[PtCl(6)] signal). The additive property of the (195)Pt NMR chemical shift is discussed. The (195)Pt NMR chemical shifts of [PtCl(dipeptide-N,N,O)(bpy)]Cl appeared at a higher field when the H attached to the dipeptide carbon atom was replaced with a methyl group. On the other hand, the (195)Pt NMR chemicals shifts of [PtCl(dipeptide-N,N,O)(diamine)] appeared at a lower field when the H attached to the diamine nitrogen atom was replaced with a methyl group, in the order of [PtCl(digly-N,N,O)(en)]Cl, [PtCl(digly-N,N,O)(N-Me-en)]Cl, and [PtCl(digly-N,N,O)(N,N'-diMe-en)]Cl.     

14-3-3 Protein, Total Tau and Phosphorylated Tau in Cerebrospinal Fluid of Patients with Creutzfeldt-Jakob Disease and Neurodegenerative Disease in Japan

1.Sporadic Creutzfeldt-Jakob disease (CJD) is a rapidly progressive and fatal disease. Patients with CJD usually become akinetic mutism within approximately 6 months. In addition, clinical signs and symptoms at early stage of sporadic CJD may not be easy to distinguish from other neurodegenerative diseases by neurological findings. However, diagnostic biochemical parameters including 14-3-3 protein, S100, neuron-specific enorase in cerebrospinal fluid (CSF) have been used as diagnostic markers, elevated titers of these markers can also be observed in CSF in other neurodegenerative diseases. Therefore, we examined other biochemical markers to discriminate CJD from other neurodegenerative diseases in CSF. 2.We analyzed CSF samples derived from 100 patients with various neurodegenerative disorders by Western blot of 14-3-3 protein, quantification of total tau (t-tau) protein, and phosphorylated tau (p-tau) protein. All patients with CJD in this study showed positive 14-3-3 protein and elevated t-tau protein (>1000 pg/mL) in CSF. We also detected positive 14-3-3 protein bands in two patients in non-CJD group (patients with dementia of Alzheimer's type; DAT) and also detected elevated t-tau protein in three patients in non-CJD group. Elevated t-tau protein levels were observed in two patients with DAT and in one patient with cerevrovascular disease in acute phase. 3.To distinguish patients with CJD from non-CJD patients with elevated t-tau protein in CSF, we compared the ratio of p-tau and t-tau proteins. The p-/t-tau ratio was dramatically and significantly higher in DAT patients rather than in CJD patients. 4.Therefore, we concluded that the assay of t-tau protein may be useful as 1st screening and the ratio of p-tau protein/t-tau protein would be useful as 2nd screening to discriminate CJD from other neurodegenerative diseases.     

Apoptosis as a mechanism of skin renewal: Ley-antigen expression is involved in an early event of a cell's commitment to apoptosis

Skin renewal is a typical example of the active participation of a cell in its own death process. Cells arising from mitotic activity in the stratum germinativum of the epidermis continuously migrate upwards to the stratum corneum, where dead cells are eventually desquamated. Recent studies have suggested that apoptosis is involved in the dynamic process of skin renewal. However, this still remains to be further elucidated. In this paper, we investigated the involvement of apoptosis in the skin renewal process. Changes in the morphology of cells in different epidermal layers were compared with histochemical analyses of the extent of DNA fragmentation, as determined by nick end-labelling, and of the reactivities to a monoclonal antibody directed to Le^y-antigen, difucosylated type 2 chain determinant, which has a close association with apoptosis, and to a monoclonal antibody directed to the proliferating cell nuclear antigen. The results show that apoptosis proceeds concomitantly with cell movement in the epidermis. It seems likely that commitment of a cell to death by apoptosis occurs in the epidermal tissue immediately after completion of cell proliferation, and that Le^y-antigen expression may be involved in the entire apoptotic process including this early event.     

“Reversion” of a Less Tumorigenic cyt Mutant of Adenovirus 12 in Induction of the Cell Surface Change

Five out of 120 clones of a cyt mutant of adenovirus 12 were not defective in induction of the cell surface change and in tumorigenicity.     

Occurrence of viable photoautotrophic picoplankton in the aphotic zone of Lake Biwa, Japan

The distribution and abundance of photoautotrophic picoplankton(PPP. Synechococcus group) in the aphotic bottom sediments ofLake Biwa were investigated by direct counting and viable counting(most probable number, MPN) methods. In the surface layer ofbottom sediments (0–1 cm). where large PPP blooms occurredin the past 5 years, >10⁵ cells cm^–3 of PPP were foundto be viable throughout the year. Furthermore, the density ofPPP deposited on the sediment surface (0–0.1 cm) was oneorder of magnitude higher (MPN = 1.3 x 10⁶ cells cm^–3.direct count = 9.9 x 10⁶ cells cm^–3) than that of bulkedsurface sediments (0–1 cm). Even in the deeper layer (13–14cm) of bottom mud, viable PPP were still found (10¹ cells cm^–1.In winter, viable PPP in the aphotic bottom sediments were 10⁴–10⁵times greater per Unit volume than those in the euphotic lakewater. Since the aphotic bottom sediments have high levels ofPPP, as well as high growth potential (high ratio of viablecount/total direct count), they are likely to seed PPP bloomsin the North Basin of Lake Biwa.     

Characterization of a 180 kDa molecule apparently reactive with recombinant L-selectin

In the present study we identified a 180 kDa molecule (p180) in rat lymph nodes (LN) apparently reactive with silkworm derived recombinant L-selectin (LEC-IgG) in a Ca2+-dependent manner. Analysis of amino acid sequence revealed that p180 has a strong homology to the macrophage mannose receptor (MMR), which was corroborated by the observation that p180 reacted with polyclonal anti-alveolar MMR antibody and mannosyl-BSA-agarose. In agreement with this notion, the binding of p180 to the silkworm LEC-IgG was inhibited by α-methyl-D-mannoside. However, in sharp contrast to its reactivity against the silkworm LEC-IgG, p180 failed to bind LEC-IgG produced by COS-7 cells, suggesting that p180 reacted with the silkworm LEC-IgG through the recognition of oligomannose-type oligosaccharides expressed on the silkworm products and that the lectin activity of L-selectin was not involved in the interaction. These results, together with the immunohistochemical studies showing that p180 was absent from the majority of high endothelial venules (HEV) but present in medullary macrophages, led us to conclude that p180 obtained from LN lysates by the use of the silkworm LEC-IgG is not a physiological ligand for L-selectin, warning against the use of recombinant proteins expressed in the baculovirus/silkworm expression system for the detection of carbohydrate ligands. Abbreviations: BSA, bovine serum albumin; EDTA, ethylenediamine-N,N,N,N-tetraacetic acid; ELISA, enzyme-linked imunosorbent assay; HEV, high endothelial venule; IgG, immunoglobulin G; LN, lymph node; NP-40, Nonidet P-40; PBS, phosphate-buffered saline; PMSF, phenylmethylsulfonyl fluoride; PVR, poliovirus receptor; SDS, sodium dodecylsulfate; SDS-PAGE, SDS-polyacrylamide gel electrophoresis; sLeX, sialyl Lewis X; WGA, wheat germ agglutinin This revised version was published online in November 2006 with corrections to the Cover Date.     

Purification and characterization of immunoglobulin production stimulating factor-IIβ derived from Namalwa cells

Two immunoglobulin production stimulating factors (IPSF) have been found in human Burkitt's lymphoma Namalwa cells. One IPSF named IPSF-II was purified and identified as glyceraldehyde-3-phosphate dehydrogenase as previously reported. We report here purification, identification and characterization of IPSF-II. IPSF-II was purified by the serial use of ammonium sulfate fractionation, hydrophobic interaction column chromatography, anion-exchange column chromatography and gel filtration. The IPSF-II was estimated as a 46 KD monomeric polypeptide by gel filtration and SDS-PAGE. Partial amino acid sequence of the 46 KD protein was analyzed for 26 amino acid residues. The sequence very closely coincided with enolase (EC 4.2.1.11) derived from various origins and, it was completely homologous with that of human enolase -chain. Rabbit muscle enolase stimulated IgM production of hybridoma lines, and IPSF-II had the enzymic activity. These results suggested that IPSF-II was -enolase or its isozyme. IPSF activities of IPSF-II was stable in alkaline conditions whereas the enzymic activity was rapidly lost in alkaline conditions. Though IPSF-II stimulated IgM production of both human-human and mouse-mouse hybridoma lines in serum-free condition, it partially suppressed IgE production of mouse-mouse hybridoma lines.     

Neurochemical and Neurogenetic Correlates of Parkinson's Disease

Abstract: We discuss neurochemical and neurogenetic correlates of Parkinson's disease (PD) based on the recent progress in the study of its etiology and pathogenesis. Nigral degeneration with the presence of Lewy bodies in the remaining neurons is the pathologic hallmark of PD, and the resultant loss of striatal dopamine is responsible for most of the clinical manifestations. Although the primary cause is still unknown, mitochondrial respiratory failure and oxidative stress appear to be two major contributors to the nigral cell death. Many endogenous and exogenous compounds with structural similarity to MPTP have been postulated as potential neurotoxins inducing nigral cell death in PD, but there is little evidence of accumulation of such compounds in the nigra. Genetic influence has increasingly been recognized as an important risk factor for PD. In this respect, genetic linkage analysis and molecular cloning of the disease genes in familial parkinsonism are of utmost importance today. Recently, the disease gene for one of the autosomal dominant forms of familial PD was identified, and we cloned the gene for an autosomal recessive type of familial parkinsonism that had been mapped to the long arm of chromosome 6 by our group. Information obtained on familial parkinsonism will contribute to the studies on sporadic PD as well.