Visualization of newly deposited tau in neurofibrillary tangles and neuropil threads

Neurofibrillary tangles (NFTs) and neuropil threads (NTs), the major hallmark of Alzheimer disease (AD), are composed of the microtubule-associated protein tau that has undergone posttranslational modifications, including deamidation and isomerization on asparaginyl or aspartyl residues. Because such modifications represent protein aging, we generated 2 antibodies, TM4, specific for Asp-387 of tau, and iD387, specific for isoAsp-387 of tau, to investigate the evolution of NFTs and NTs. On Western blots of Sarkosyl-insoluble fractions, TM4 strongly labeled paired helical filament-tau (PHF-tau), whereas iD387 preferentially labeled PHF smear. Thus, it is reasonable to postulate that TM4-labeled tau (unmodified tau species) represents more recent deposition, and iD387-labeled tau (modified tau species) represents earlier deposition. Unexpectedly, TM4 immunostained even highly evolved NFTs, suggesting that deposition of newly produced tau continues until neuronal death. iD387 labeled the whole profile of NFTs up to distal dendritic branches, whereas TM4 staining was localized to particular portions of NFTs in proximal dendrites and neuronal perikarya. In NTs, TM4 preferentially labeled the outer portion, whereas iD387 intensely labeled the core portion. Based on TM4-positive NFT counts and total NFT counts, we speculate that NFTs in the human hippocampus are produced at a constant rate irrespective of the disease stage.     

Effects of fasting and refeeding on jejunal morphology and cellular activity in rats in relation to depletion of body stores

BACKGROUND: Intestinal mucosa atrophy following a period of starvation characterized by the mobilization of fat stores for energy expenditure (phase II) worsen after a long fast marked by an increase in protein catabolism (phase III). However, the morphology of the jejunum is completely restored after 3 days of refeeding. The aim of this study was to determine the mechanisms involved in the rapid jejunal restoration following the critical phase III. METHODS: Jejunal structure was observed through conventional and environmental scanning electron microscopy, whilst cellular dynamics were studied using classical optic microscopy tools and immunohistochemistry. RESULTS: Mucosal structural atrophy during fasting proved to worsen over the two phases. During phase II, apoptosis is still present at the tip of the villi, the number of mitosis in crypts showed a 30% decrease and a transient drop in cell migration is observed. During phase III, however, an 85% rise in mitosis was noticed along with an increase in cell migration and the disappearance of apoptotic cells at the villus tips. This increased cell renewal continues after food ingestion. CONCLUSIONS: Starved rats appeared to be in a phase of energy sparing in phase II, with depressed cellular events in the intestinal mucosa. In phase III, however, the preservation of functional cells and the early increase in crypt cell proliferation should prepare the mucosa to refeeding and could explain why jejunal repairs are complete after 3 days of refeeding following either phase II or phase III.     

CXCR4 expression in vitreoretinal membranes

BACKGROUND/AIM: Proliferative vitreoretinopathy (PVR) and macular pucker (MP) vitreoretinal membranes are caused by abnormal cell migration. By their role in chemotactism, chemokine receptors represent good candidates to sustain this process. The authors thus investigated the expression of one of them, CXCR4, in these pathologies. METHODS: Three PVR and four MP membranes were surgically removed and processed for immunochemical studies with antibodies for CXCR4, cytokeratins or smooth muscle actin. RESULTS: CXCR4 expression was found in all membranes. There was no relation between severity of PVR or MP and presence of CXCR4. In addition, there was no difference in CXCR4 expression between MP and PVR. CONCLUSION: CXCR4 is expressed in PVR and MP. Further experiments are needed to test if CXCR4 and other chemokine receptors are implicated in vitreoretinal membrane formation.     

Anti-obesity action of Salix matsudana leaves (Part 2). Isolation of anti-obesity effectors from polyphenol fractions of Salix matsudana

Previously, it was reported that polyphenol fractions prepared from the leaves of Salix matsudana reduced the elevation of the rat plasma triacylglycerol level at 3 and 4 h after oral administration of a lipid emulsion containing corn oil, at a dose of 570 mg/kg. Moreover, body weights at 2-9 weeks and the fi nal parametrial adipose tissue weights were significantly lower in mice fed the high-fat diet with 5% polyphenol fractions of S. matsudana leaves than in those fed the high-fat diet alone. The polyphenol fractions of S. matsudana leaves also significantly reduced the hepatic total cholesterol content, which was elevated in mice fed the high-fat diet alone. In addition, the polyphenol fractions of S. matsudana leaves inhibited palmitic acid uptake into brush border membrane vesicles prepared from rat jejunum and alpha-amylase activity, and their fractions enhanced norepinephrine-induced lipolysis in fat cells. To clarify the active substances inhibiting the palmitic acid uptake into small intestinal brush border membrane, the alpha-amylase activity or enhancing the norepinephrine-induced lipolyis in fat cells, the isolation of the active substances from polyphenol fraction was attempted using the above three assay systems. Compounds 1, 2 and 3 were isolated from the polyphenol fractions and identified as apigenin-7-O-d-glucoside, luteolin-7-O-d-glucoside and chrysoeriol-7-O-d-glucoside, respectively. Among three flavonoids, apigenin-7-O-d-glucoside inhibited alpha-amylase activity, and luteolin-7-O-d-glucoside and chrysoeriol-7-O-d-glucoside inhibited palmitic acid uptake into small intestinal brush border membrane. Furthermore, three flavonoid glucosides enhanced norepinephrine-induced lipolysis in fat cells.     

Gender-dependent differences in the incidence of ochratoxin A-induced neural tube defects in the Pdn/Pdn mouse

Genetic polydactyly/arhinencephaly mouse embryo, Pdn/Pdn , exhibits suppression of Gli3 gene expression. Ochratoxin A (OTA) is a teratogen that causes neural tube defects (NTD) in mice. We investigated gender-dependent differences in the incidence of NTD induced by OTA in the Pdn/Pdn mouse. After administering 2 mg/kg OTA to Pdn /+ female mice, mated with Pdn /+ males, on day 7.5 of gestation, we examined the genotypes, sex and NTD of fetuses on day 18. Non-treated Pdn / Pdn had a 15.8% risk of NTD, and all NTD fetuses were female. When Pdn / Pdn embryos were exposed to OTA, the incidence of NTD increased to 16 (51.6%) of 31 Pdn / Pdn fetuses, and 10 (71.4%) of 14 male Pdn / Pdn fetuses exhibited NTD. From these results, it was speculated that NTD in OTA-treated male Pdn / Pdn were due to the synergistic effect between depressed Gli3 and altered sex-correlated gene expression from OTA treatment. After treatment with OTA, the embryos were recovered on day 9 and gene expressions, which were correlated with Gli3 , telencephalic morphogenesis, formation of gonadal anlage, and gender-dependent differentiation were investigated. From real-time polymerase chain reaction analysis results, it was suggested that the manifestation of NTD in the male OTA-treated Pdn/Pdn might be due to the complicated altered gene expressions among Gli3, Wnt7b, Wnt8b , Fez1 , Barx1, Lim1, Dmrt1, Igf1 , Fog2, Dax1 and Sox9, and in particular, upregulation and gender-dependent difference in Barx1 and gender-dependent difference in Sox9 gene expressions might be noteworthy findings.     

Estrogen actions on lactotroph proliferation are independent of a paracrine interaction with other pituitary cell types: a study using lactotroph-enriched cells

The mitogenic action of estrogen on estrogen-responsive tissues is suggested to be mediated by paracrine growth factors secreted from neighboring estrogen receptor-positive cells. Using pituitary lactotrophs in primary culture, on which estrogen exerts both mitogenic and antimitogenic actions in a cell context-dependent manner, we investigated whether a paracrine cell-to-cell interaction with other pituitary cell types was required for estrogen action. In pituitary cells, enriched for lactotrophs by 85% using differential sedimentation on a discontinuous Percoll gradient, 17beta-estradiol (E2) showed an antimitogenic action on lactotrophs in the presence of IGF-I, which was similar to that in control unenriched cells. Mitogenic actions were also seen in lactotroph-enriched cells when E2 was administered alone, in combination with serum, or in combination with the adenylate cyclase activator forskolin. Similar results were obtained in 90% lactotroph-enriched cells collected by fluorescence-activated cell sorting from transgenic rats expressing enhanced green fluorescent protein under the control of the prolactin promoter. The putative role of basic fibroblast growth factor (bFGF) as a paracrine factor mediating the mitogenic action of estrogen was not supported by the results that: 1) bFGF inhibited lactotroph proliferation; 2) immunoneutralization of bFGF failed to block E2-induced proliferation; and 3) cellular bFGF levels were not altered by E2 treatment. These results suggest that the antimitogenic and mitogenic actions of estrogen on lactotrophs do not require paracrine signals from other pituitary cell types and that estrogen directly influences lactotroph proliferation.     

Association of <Emphasis Type="Italic">TP53</Emphasis>codon 72 polymorphism and the outcome of adjuvant therapy in breast cancer patients

Introduction  

Single-nucleotide polymorphisms (SNPs) in codon 72 of the TP53 (also known as p53) gene (rs1042522) and in the promoter region of the MDM2 gene (SNP309; rs2279744) have been suggested to play roles in many cancers. We investigated whether these SNPs were associated with patient outcome and the effect of adjuvant systemic therapy.     

Expression of the chemokine receptor CCR6 in the Lewis lung carcinoma (LLC) cell line reduces its metastatic potential in vivo

Chemokines and their receptors play important roles in various aspects of tumoral processes, and evidence was provided for their critical involvement in determining the metastatic destination of tumor cells. Here, we analyzed in vitro and in vivo, how CCR6 expression could alter the behavior of Lewis lung carcinoma (LLC) cells, which were shown to express low levels of the CCR6 ligand, CCL20 (LARC), both in vitro and in vivo. The expression of CCR6 significantly decreased the number of metastases in immunocompetent C57BL/6 mice, without affecting the tumor-forming ability of LLC cells. This was correlated with a decrease in clonogenicity in soft and hard agar, and with increased adhesion to type-IV collagen. These two observations made in basal conditions were enhanced when CCL20 was added to the assay medium. Thus, expression of CCR6 in tumor cells, associated with the local production of CCL20, decreased the metastatic potential of the LLC line. We propose a model, in which the expression of a chemokine receptor in tumor cells can act as a metastasis-suppressor, or a metastasis-promoting factor, according to the expression, or the absence of expression of the cognate ligand(s) in the tumor.     

Cyanidin 3-glucoside ameliorates hyperglycemia and insulin sensitivity due to downregulation of retinol binding protein 4 expression in diabetic mice

Adipocyte dysfunction is strongly associated with the development of obesity and insulin resistance. It is accepted that the regulation of adipocytokine expression is one of the most important targets for the prevention of obesity and improvement of insulin sensitivity. In this study, we have demonstrated that anthocyanin (cyanidin 3-glucoside; C3G) which is a pigment widespread in the plant kingdom, ameliorates hyperglycemia and insulin sensitivity due to the reduction of retinol binding protein 4 (RBP4) expression in type 2 diabetic mice. KK-A(y) mice were fed control or control +0.2% of a C3G diet for 5 weeks. Dietary C3G significantly reduced blood glucose concentration and enhanced insulin sensitivity. The adiponectin and its receptors expression were not responsible for this amelioration. C3G significantly upregulated the glucose transporter 4 (Glut4) and downregulated RBP4 in the white adipose tissue, which is accompanied by downregulation of the inflammatory adipocytokines (monocyte chemoattractant protein-1 and tumor necrosis factor-alpha) in the white adipose tissue of the C3G group. These findings indicate that C3G has significant potency in an anti-diabetic effect through the regulation of Glut4-RBP4 system and the related inflammatory adipocytokines.