Role of proteoglycan synthesis genes in osteosarcoma stem cells.

Osteosarcoma stem cells (OSCs) contribute to the pathogenesis of osteosarcoma (OS), which is the most common malignant primary bone tumor. The significance and underlying mechanisms of action of proteoglycans (PGs) and glycosaminoglycans (GAGs) in OSC phenotypes and OS malignancy are largely unknown. This study aimed to investigate the role of PG/GAG biosynthesis and the corresponding candidate genes in OSCs and poor clinical outcomes in OS using scRNA-seq and bulk RNA-seq datasets of clinical OS specimens, accompanied by biological validation by in vitro genetic and pharmacological analyses. The expression of ß-1,3-glucuronyltransferase 3 (B3GAT3), one of the genes responsible for the biosynthesis of the common core tetrasaccharide linker region of PGs, was significantly upregulated in both OSC populations and OS tissues and was associated with poor survival in patients with OS with high stem cell properties. Moreover, the genetic inactivation of B3GAT3 by RNA interference and pharmacological inhibition of PG biosynthesis abrogated the self-renewal potential of OSCs. Collectively, these findings suggest a pivotal role for B3GAT3 and PG/GAG biosynthesis in the regulation of OSC phenotypes and OS malignancy, thereby providing a potential target for OSC-directed therapy.

Bioinformatic analysis reveals potential relationship between chondrocyte senescence and protein glycosylation in osteoarthritis pathogenesis.

Osteoarthritis (OA) is the most common degenerative and progressive joint disease. Cellular senescence is an irreversible cell cycle arrest progressive with age, while protein glycosylation is the most abundant post-translational modification, regulating various cellular and biological pathways. The implication of either chondrocyte senescence or protein glycosylation in the OA pathogenesis has been extensively and individually studied. In this study, we aimed to investigate the possible relationship between chondrocyte senescence and protein glycosylation on the pathogenesis of OA using single-cell RNA sequencing datasets of clinical OA specimens deposited in the Gene Expression Omnibus database with a different cohort. We demonstrated that both cellular senescence signal and protein glycosylation pathways in chondrocytes are validly associated with OA pathogenesis. In addition, the cellular senescence signal is well-connected to the O-linked glycosylation pathway in OA chondrocyte and vice-versa. The expression levels of the polypeptide N-acetylgalactosaminyltransferase (GALNT) family, which is essential for the biosynthesis of O-Glycans at the early stage, are highly upregulated in OA chondrocytes. Moreover, the expression levels of the GALNT family are prominently associated with chondrocyte senescence as well as pathological features of OA. Collectively, these findings uncover a crucial relationship between chondrocyte senescence and O-linked glycosylation on the OA pathophysiology, thereby revealing a potential target for OA.

Ameliorative effect of the oil components derived from sweet potato shochu on impaired short-term memory in mice after amyloid ß25-35 injection.

Sweet potato shochu oil is a by-product of shochu production and usually discarded although some physiological functions are considered. In this study, we investigated the effects of shochu oil on short-term memory using a murine model of spontaneous alternating behavior induced by the intracerebroventricular (ICV) administration of amyloid ß25-35 (Aß25-35). Mice were orally administered shochu oil for 15 days. Experiments with a Y-maze model revealed that the Aß25-35 caused a significant decrease in spontaneous alternation behavior, and supplementation with shochu oil significantly improved this behavior. DNA microarray analysis revealed that the administration of shochu oil downregulated the expression of S100a9 and Ptgs2, which reportedly exacerbate amyloid ß deposition in Alzheimer's disease. The administration of shochu oil upregulated the expression of Dnaja1 and PP2A, which is typically downregulated in Alzheimer's disease. These data suggest that shochu oil possible ameliorates on impaired short-term memory in mice after amyloid ß25-35 injection, as indicated by its effects on improving spontaneous alternation behavior and modulating the expressions of related genes.

Hair growth-promoting activity of components derived from sweet potato shochu.

Sweet potato shochu oil is one of the by-products of sweet potato shochu production. We investigated the functionality and industrial use of shochu oil as a food-derived raw material. Because of the increased incidence of self-consciousness in people owing to thinning hair, in this study, we examined the hair growth-inducing effects of shochu oil. Minoxidil, the only topical medication approved for hair growth treatment in Japan, was used as a control for the evaluation of hair growth-promoting activity of shochu oil. Human follicle dermal papilla cells treated with shochu oil showed upregulated expression of vascular endothelial growth factor in a concentration-dependent manner, indicating that shochu oil induced the activation of the hair growth cycle. In vivo, epidermal treatment with shochu oil also promoted hair growth in C3H mice. More than 35 components were detected in shochu oil via gas chromatography-mass spectrometry. The main components, accounting for 98.5% of shochu oil, were as follows, in order of decreasing concentration: ethyl palmitate, ethyl linoleate, ethyl oleate, ethyl stearate, ethyl caprate, ethyl laurate, ethyl myristate, and ethyl α-linolenate. Among these, ethyl palmitate, ethyl linoleate, and ethyl α-linolenate promoted hair growth in C3H mice. These results indicate that shochu oil can be used as a hair restorer. To the best of our knowledge, this study is the first to demonstrate the hair growth-promoting activity of shochu oil.

Thermal stabilization of formaldehyde dehydrogenase by encapsulation in liposomes with nicotinamide adenine dinucleotide.

The thermal stability of formaldehyde dehydrogenase (FaDH) from Pseudomonas sp. was examined and controlled by encapsulation in liposomes with ß-reduced nicotinamide adenine dinucleotide (NADH). The activity of 4.8 µg/mL free FaDH at pH 8.5 in catalyzing the oxidation of 50mM formaldehyde was highly dependent on temperature so that the activity at 60 °C was 27 times larger than that at 25 °C. Thermal stability of the FaDH activity was examined with and without liposomes composed of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Rapid deactivation of free FaDH was observed at 60 °C because of its dissociation into two subunits. The rate of dissociative deactivation of POPC liposome-encapsulated FaDH was smaller than that of the free enzyme. The liposomal FaDH was however progressively deactivated for the incubation period of 60 min eventually leading to complete loss of its activity. The free FaDH and NADH molecules were revealed to form the thermostable binary complex. The thermal stability of POPC liposome-encapsulated FaDH and NADH system was significantly higher than the liposomal enzyme without cofactor. The above results clearly show that NADH is a key molecule that controls the activity and stability of FaDH in liposomes at high temperatures.

Stability and reactivity of liposome-encapsulated formate dehydrogenase and cofactor system in carbon dioxide gas-liquid flow.

Formate dehydrogenase from Candida boidinii (CbFDH) is potentially applicable in reduction of CO(2) through oxidation of cofactor NADH into NAD(+). For this, the CbFDH activity needs to be maintained under practical reaction conditions, such as CO(2) gas-liquid flow. In this work, CbFDH and cofactor were encapsulated in liposomes and the liposomal enzymes were characterized in an external loop airlift bubble column. The airlift was operated at 45 degrees C with N(2) or CO(2) as gas phase at the superficial gas velocity U(G) of 2.0 or 3.0 cm/s. The activities of liposomal CbFDH/cofactor systems were highly stable in the airlift regardless of the type of gas phase because liposome membranes prevented interactions of the encapsulated enzyme and cofactor molecules with the gas-liquid interface of bubbles. On the other hand, free CbFDH was deactivated in the airlift especially at high U(G) with CO(2) bubbles. The liposomal CbFDH/NADH could catalyze reduction of CO(2) in the airlift giving the fractional oxidation of the liposomal NADH of 23% at the reaction time of 360 min. The cofactor was kept inside liposomes during the reaction operation with less than 10% of leakage. All of the results obtained demonstrate that the liposomal CbFDH/NADH functions as a stable catalyst for reduction of CO(2) in the airlift.

Common behavioral influences of the ErbB1 ligands transforming growth factor alpha and epiregulin administered to mouse neonates.

Ligands for epidermal growth factor (EGF) receptor (ErbB1), such as EGF, transforming growth factor alpha (TGFalpha), and epiregulin, are enriched in body fluids and blood and regulate development of various peripheral organs. It remains however how such circulating polypeptide growth factors influence brain development and function. Here, we performed peripheral injections of TGFalpha and epiregulin to mouse neonates and evaluated immediate physical and neurochemical development and later behavioral consequences. Subcutaneous administration of TGFalpha and epiregulin increased phosphorylation of brain ErbB1, suggesting their effects on brain development. Repeated their injections similarly enhanced physical development of eyelid opening and tooth eruption during early postnatal stage and resulted in abnormal behavioral traits in the adult stage. Acoustic startle responses of mice treated with these growth factors as neonates were enhanced and prepulse inhibition was decreased without an apparent correlation between prepulse inhibition level and startle intensity. Locomotor activity and fear-learning performance with tone and context cues were not altered, however. These results suggest that circulating ErbB1 ligands in the periphery of neonates have some common influences on later behavioral traits. Abnormal ErbB1 ligand production at neonatal and potentially prenatal stages might therefore associate with neurodevelopmental disorders such as schizophrenia.

Changes in polyphenolic content and radical-scavenging activity of sweet potato (Ipomoea batatas L.) during storage at optimal and low temperatures.

Polyphenolic content and radical-scavenging activities (RSA) of four sweet potato (Ipomoea batatas L.) cultivars were characterized after storage at optimal (15 degrees C) or low temperature (5 degrees C) for 0, 13, 26, and 37 days. The polyphenolic content increased during storage in three cultivars but not in 'Murasakimasari'. The change in 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity (DPPH-RSA) correlated very well with polyphenolic content. The increases in polyphenolics and the RSA in 'Benimasari' were significantly greater during storage at 5 degrees C than at 15 degrees C. The main polyphenolic components in all cultivars were chlorogenic acid (ChA) and 3,5-di-O-caffeoylquinic acid (3,5-diCQA). ChA level increased more at 5 degrees C than at 15 degrees C, whereas that of 3,5-diCQA was greater at 15 degrees C. Caffeoylquinic acids and RSA in 'Murasakimasari', which contains a large amount of anthocyanin in flesh tissue, were extremely high at the beginning of storage and remained nearly constant or decreased over time. A non-caffeoylquinic acid component that increased during storage, especially in 'J-Red' at 15 degrees C, was purified by successive chromatographic steps. The isolate was identified as caffeoyl sucrose [CSu, 6-O-caffeoyl-(beta- d-fructofuranosyl-(2-->1))-alpha-D-glucopyranoside] by fast atom bombardment-mass spectroscopy (FAB-MS), infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). These results suggest that storage under cultivar-dependent, controlled temperature is one approach for increasing desirable physiologic function associated with RSA of polyphenolic compounds in sweet potato roots.

Permeabilization of phospholipid bilayer membranes induced by gas-liquid flow in an airlift bubble column.

The permeability of 5(6)-carboxyfluorescein (CF) through the phospholipid bilayer membranes was measured by using the system in which the CF-containing phospholipid vesicles (liposomes) were suspended in the gas-liquid flow in an external loop airlift bubble column. The airlift was operated at various superficial gas velocities UG up to 2.4 cm/s at 25 and 40 degrees C. The CF-containing liposomes composed of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) had the nominal diameters of 50, 100, and 200 nm. The 50- and 100-nm liposomes were stable at 40 degrees C for 5 h even at a high UG value of 2.4 cm/s based on the observed turbidity of the liposome suspension in the airlift. On the other hand, the 200-nm liposomes were stable at a low UG value of 1.4 cm/s, although a progressive decrease in size of the liposomes was implied at the high UG value of 2.4 cm/s. The permeability coefficient PCF of CF through the lipid membrane of the 100-nm liposomes was significantly increased with increasing UG at a high temperature of 40 degrees C, while at a low temperature of 25 degrees C the PCF value was little dependent on UG. As a typical result on the above liposomes, the PCF value (9.2 x 10(-11) cm/s) at 40 degrees C and UG = 2.4 cm/s in the airlift was more than 15 times larger than that at 25 degrees C in the static liquid corresponding to UG = 0. In addition, the dependence of the PCF value on UG at 40 degrees C became more significant with increasing the size of liposomes suspended. The results obtained revealed that the permeability of the liposome membranes could be regulated by suspending the liposomes in the gas-liquid flow in the airlift without modulating the membrane composition of liposomes.

Growth suppression of human cancer cells by polyphenolics from sweetpotato (Ipomoea batatas L.) leaves.

Sweetpotato leaves (Ipomoea batatas L.) contain a high content of polyphenolics that consist of caffeic acid, chlorogenic acid, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, 4,5-di-O-caffeoylquinic acid, and 3,4,5-tri-O-caffeoylquinic acid. We investigated the suppression of the proliferation of selected human cancer cells by phenolic compounds isolated from sweetpotato leaf. The human cancer cells used in this research included a stomach cancer (Kato III), a colon cancer (DLD-1), and a promyelocytic leukemia cell (HL-60). Caffeic acid and di- and tricaffeoylquinic acids dose-dependently depressed cancer cell proliferation, and the difference in sensitivity between caffeoylquinic acid derivatives and each kind of cancer cell was observed. Specifically, 3,4,5-tri-O-caffeoylquinic acid effectively depressed the growth of three kinds of cancer cells, and caffeic acid had an exceptionally higher effect against HL-60 cells than other di- and tricaffeoylquinic acids. In attempting to clarify the mechanism of growth suppression with the addition of the apoptotic inhibitor N-ethylmaleimide, we observed that the nuclear granulation in 3,4,5-tri-O-caffeoylquinic acid-treated HL-60 cells suggested apoptosis induction. This effect was confirmed by DNA fragmentation, an increase of caspase-3 activity, and expression of c-Jun. Growth suppression of HL-60 cells by 3,4,5-tri-O-caffeoylquinic acid was determined to be the result of apoptotic death of the cells. These results indicate that 3,4,5-tri-O-caffeoylquinic acid may have potential for cancer prevention.

Enzymatic production of caffeic acid by koji from plant resources containing caffeoylquinic acid derivatives.

The effect of a koji (Aspergillus awamori mut.) extract on the caffeoylquinic acid derivatives purified from sweetpotato (Ipomoea batatas L.) leaves was examined to develop the mass production of caffeic acid. A koji extract hydrolyzed the caffeoylquinic acid derivatives, chlorogenic acid, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, 4,5-di-O-caffeoylquinic acid and 3,4,5-tri-O-caffeoylquinic acid, to caffeic acid. Furthermore, the koji extract also converted the major polyphenolic components from sweetpotato, burdock (Arctium lappa L.), and mugwort (Artemisia indica var. maximowiczii) leaves to caffeic acid. These results suggest that the production of caffeic acid from plant resources containing caffeoylquinic acid derivatives is possible.

Molecular Mechanisms Behind the Chemopreventive Effects of Anthocyanidins.

Anthocyanins are polyphenolic ring-based flavonoids, and are widespread in fruits and vegetables of red-blue color. Epidemiological investigations and animal experiments have indicated that anthocyanins may contribute to cancer chemoprevention. The studies on the mechanism have been done recently at molecular level. This review summarizes current molecular bases for anthocyanidins on several key steps involved in cancer chemoprevention: (i) inhibition of anthocyanidins in cell transformation through targeting mitogen-activated protein kinase (MAPK) pathway and activator protein 1 (AP-1) factor; (ii) suppression of anthocyanidins in inflammation and carcinogenesis through targeting nuclear factor kappa B (NF- $\kappa$ B) pathway and cyclooxygenase 2 (COX-2) gene; (iii) apoptotic induction of cancer cells by anthocyanidins through reactive oxygen species (ROS) / c-Jun NH(2)-terminal kinase (JNK)-mediated caspase activation. These data provide a first molecular view of anthocyanidins contributing to cancer chemoprevention.

Accumulation of phosphorylated alpha-synuclein in the brain and peripheral ganglia of patients with multiple system atrophy.

We immunohistochemically examined the brain and peripheral sympathetic ganglia from eight patients with multiple system atrophy (MSA), using an antibody specific for phosphorylated alpha-synuclein (anti-PSer129). Phosphorylated alpha-synuclein was deposited in five cellular locations: oligodendroglial cytoplasm and nucleus, and neuronal cytoplasm, processes and nucleus. Many neuronal cytoplasmic inclusions (NCIs) were found in the pontine and inferior olivary nuclei and, to a lesser extent, in the substantia nigra, locus ceruleus, and neocortical and hippocampal neurons. NCIs were also found in the sympathetic ganglia in two out of the eight cases. Moreover, anti-PSer129 immunohistochemistry revealed extensive neuropil pathology; swollen neurites were abundant in the pontine nucleus, delicate neurites were observed in the deeper layers of the cerebral cortex and thalamus, and neuropil threads and dot-like structures were distributed in the basal ganglia and brainstem. Diffuse neuronal cytoplasmic staining (pre-NCI) was frequently found in the pontine and inferior olivary nuclei. Thus, the widespread accumulation of phosphorylated alpha-synuclein in both glial and neuronal cells is a pathological feature in patients suffering from MSA.

Potential chemopreventive properties of anthocyanin-rich aqueous extracts from in vitro produced tissue of sweetpotato (Ipomoea batatas L.).

Anthocyanin-rich aqueous extracts from cell suspension cultures of a high anthocyanin-producing sweetpotato PL (purple line) cell line grown under two different media conditions, MM (multiplication medium) and APM (high anthocyanin-producing medium) and from the cell line's donor tissue, field-grown storage root (SR) of sweetpotato, cv. Ayamurasaki, were evaluated for antioxidative (DPPH test), antimutagenic (Salmonella/reversion assay; mutagen, Trp-P-1), and antiproliferative (human promyelocytic leukaemia cells HL-60) activities. Both cell line extracts MM and APM exhibited higher radical scavenging activities (RSA), 3.8- and 1.4-fold, respectively, than the SR extract. The antimutagenic activity of all extracts was found to be dose-dependent. At a dose of 1 mg/plate, the highest activity exhibited APM (73% inhibition of Trp-P-1-induced reverse mutation of Salmonella typhimurium TA98), followed by MM (54% inhibition) and SR (36% inhibition). The MM extract was the strongest inhibitor of the proliferation of human promyelocytic leukemia cells. At a concentration of 1.6 mg/mL medium during 24 h, it suppressed the growth of 47% of HL-60 cells. A significantly lower growth suppression effect displayed APM and SR extracts (21 and 25%, respectively). Total anthocyanin levels and anthocyanin composition in evaluated samples seem to be related to their activities. The MM extract, which exhibited the highest RSA and antiproliferation activities, contained the highest level of anthocyanins. Among them, nonacylated cyanidin 3-sophoroside-5-glucoside dominated. It is speculated that the presence of this anthocyanin contributed toward enhanced activities of MM extract.

Anthocyanidins induce apoptosis in human promyelocytic leukemia cells: structure-activity relationship and mechanisms involved.

Anthocyanidins are the aglycon nucleuses of anthocyanins, which are reddish pigments widely spread in colored fruits and vegetables. To investigate their anti-cancer effect, induction of apoptosis was tested in human promyelocytic leukemia cells (HL-60), which is a valid model for testing antileukemic or general antitumoral compounds. Of six anthocyanidins representing the aglycons of most of anthocyanins, only those with an ortho-dihydroxyphenyl structure on the B-ring induce apoptosis, suggesting that the ortho-dihydroxyphenyl structure of anthocyanidins may contribute to the induction of apoptosis. Delphinidin, the most potent inducer, causes apoptosis in a time- and dose-dependent manner. The efficacious induction of apoptosis was observed at 100 micro M for 6 h. Concomitant with the apoptosis, delphinidin stimulates JNK pathway activation including JNK phosphorylation and c-jun gene expression, and activates caspase-3. Antioxidants including N-acetyl-L-cysteine (NAC) and catalase effectively block delphinidin-induced JNK phosphorylation, caspase-3 activation, and DNA fragmentation. Moreover, anthocyanidins directly cause HL-60 cells to generate intracellular hydrogen peroxide. Thus, anthocyanidins may trigger an apoptotic death program through an oxidative stress-involved JNK signaling pathway. The induction of apoptosis by anthocyanins may be the pivotal mechanism by which its chemopreventive action against cancer is based.

Upregulation of alpha-synuclein by lipopolysaccharide and interleukin-1 in human macrophages.

Alpha-synuclein was originally identified as the presynaptic nerve terminal protein. Recently, we reported that alpha-synuclein is also expressed in cultured human astrocytes and that its levels are increased by stimulation with interleukin-1beta, suggesting that it may be involved in inflammatory processes. We therefore investigated the effect of inflammatory stimuli on alpha-synuclein expression in human macrophages. Alpha-synuclein mRNA and protein were detected in cultured human macrophages and levels of alpha-synuclein protein were increased by stimulation with lipopolysaccharide and interleukin-1beta in a time- and concentration-dependent manner. Immunofluorescent staining showed that alpha-synuclein protein was expressed within the cytoplasm and nucleus. Furthermore, alpha-synuclein immunoreactivity was present in alveolar macrophages from human lung tissues. These findings suggest that the function of alpha-synuclein is not exclusive to the nervous system and that alpha-synuclein may play a role in inflammatory processes and immune responses.

Identification and characterization of foliar polyphenolic composition in sweetpotato (Ipomoea batatas L.) genotypes.

Trials over two years were conducted using 1389 sweetpotato (Ipomoea batatas L.) genotypes collected from all over the world to characterize the polyphenolic composition in sweetpotato leaves. Wide variation was observed in relation to their total and individual leaf polyphenolic constituents. In all genotypes studied, the total polyphenol contents of sweetpotato leaf ranged from 1.42 to 17.1 g/100 g dry weight. The six different polyphenolic compounds were identified and quantified by NMR, FABMS, and RPHPLC analysis procedures. This is the first report of polyphenolic compositions in sweetpotato leaves. The relative levels of polyphenolic acids in sweetpotato leaves were as follows: 3,5-di-O-caffeoylquinic acid > 4,5-di-O-caffeoylquinic acid > chlorogenic acid (3-O-caffeoylquinic acid) > 3,4-di-O-caffeoylquinic acid > 3,4,5-tri-O-caffeoylquinic acid > caffeic acid. The highest 3,4,5-tri-O-caffeoylquinic acid and 4,5-di-O-caffeoylquinic acid occurred at 221 and 1183.30 mg/100 g dry weight, respectively.

A cysteine protease inhibitor prevents suspension-induced declines in bone weight and strength in rats.

In this study, we examined the effects of a potent cysteine protease inhibitor, N-(L-3-trans-carboxyoxirane-2-cabonyl)-L-leucine-4-aminobutylamide (E-64a), on bone weight and strength in tail-suspended rats. We first administered a vehicle or 4 or 8 mg/rat of E-64a to rats fed with a low calcium diet for 7 wks to determine effective doses of E-64a on bone resorption in vivo. Femoral cathepsin K-like activity and serum hydroxyproline level in rats fed with a low calcium diet were significantly higher than those in rats fed with a standard diet. The intraperitoneal injection of 8 mg/rat of E-64a to rats decreased their serum calcium and hydroxyproline concentrations after 3 to 6 hrs in parallel with changes in femoral cathepsin K-like activity, while 4 mg/rat of E-64a had weaker effects on these parameters. Based on these results, we injected 8 mg/rat of E-64a to tail-suspended rats twice a day for 2 wks and compared the results with those of treatment with 1 mg/rat of etidronate, a bisphosphonate, twice a week. In tail-suspended rats, femoral weight and strength, assessed by three-point bending test, significantly decreased from Day 5 to 21, while femoral cathepsin K-like activity and serum calcium and hydroxyproline concentrations did not change. E-64a inhibited femoral cathepsin K-like activity in tail-suspended rats, but etidronate did not. E-64a as well as etidronate significantly prevented the suspension-induced declines in bone weight and strength. However, more frequent injection and higher doses were required for E-64a to exhibit significant efficacy of antiresorption, compared with those of etidronate. Our results suggest that a cysteine protease inhibitor could improve suspension-induced osteopenia by inhibiting cathepsin K-like activity in bone; however, it needs several improvements in the effect as a clinical drug.

Molecular characterization of mammalian dicarbonyl/L-xylulose reductase and its localization in kidney.

In this report, we first cloned a cDNA for a protein that is highly expressed in mouse kidney and then isolated its counterparts in human, rat hamster, and guinea pig by polymerase chain reaction-based cloning. The cDNAs of the five species encoded polypeptides of 244 amino acids, which shared more than 85% identity with each other and showed high identity with a human sperm 34-kDa protein, P34H, as well as a murine lung-specific carbonyl reductase of the short-chain dehydrogenase/reductase superfamily. In particular, the human protein is identical to P34H, except for one amino acid substitution. The purified recombinant proteins of the five species were about 100-kDa homotetramers with NADPH-linked reductase activity for alpha-dicarbonyl compounds, catalyzed the oxidoreduction between xylitol and l-xylulose, and were inhibited competitively by n-butyric acid. Therefore, the proteins are designated as dicarbonyl/l-xylulose reductases (DCXRs). The substrate specificity and kinetic constants of DCXRs for dicarbonyl compounds and sugars are similar to those of mammalian diacetyl reductase and l-xylulose reductase, respectively, and the identity of the DCXRs with these two enzymes was demonstrated by their co-purification from hamster and guinea pig livers and by protein sequencing of the hepatic enzymes. Both DCXR and its mRNA are highly expressed in kidney and liver of human and rodent tissues, and the protein was localized primarily to the inner membranes of the proximal renal tubules in murine kidneys. The results imply that P34H and diacetyl reductase (EC ) are identical to l-xylulose reductase (EC ), which is involved in the uronate cycle of glucose metabolism, and the unique localization of the enzyme in kidney suggests that it has a role other than in general carbohydrate metabolism.

Alpha-synuclein immunoreactivity in normal and neoplastic Schwann cells.

Alpha-synuclein is known to play an important role in several neurodegenerative diseases. Moreover, it is expressed in central nervous system neuronal tumors, and another member of the synuclein family, gamma-synuclein, is overexpressed in breast and ovarian carcinomas. However, the expression of alpha-synuclein has not been reported hitherto in the peripheral nervous system (PNS). In the present study, we investigated normal PNS tissue and schwannomas in human postmortem and biopsy samples using both immunocytochemistry and immunoelectron microscopy with antibodies against alpha-, beta- and gamma-synuclein. In normal PNS tissue, Schwann cells, but not axons or myelin, were immunopositive for alpha-synuclein. In schwannomas, almost all of the tumor cells showed diffuse cytoplasmic staining for alpha-synuclein (30 cases). Ultrastructurally, alpha-synuclein immunoreactivity was found in the cytoplasm of normal and neoplastic Schwann cells, in association with the plasma membrane, ribosomes, rough endoplasmic reticulum, small vesicles, Golgi apparatus and the nuclear outer membrane. No beta- or gamma-synuclein immunoreactivity was found in those cells. These results indicate that in the PNS, alpha-synuclein is a useful marker of Schwann cells and that it is not involved in tumorigenesis.