MedWorm: Biochemistry

Disruption of the mitotic kinesin eg5 gene (knsl1) results in early embryonic lethality.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:05:11 +0100

Disruption of the mitotic kinesin Eg5 gene (Knsl1) results in early embryonic lethality.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):513-9

Authors: Chauvière M, Kress C, Kress M

Eg5, a member of the widely conserved kinesin-5 family, is a plus-end-directed motor involved in separation of centrosomes, and in bipolar spindle formation and maintenance during mitosis in vertebrates. To investigate the requirement for Eg5 in mammalian development, we have generated Eg5 deficient mice by gene targeting. Heterozygous mice are healthy, fertile, and show no detectable phenotype, whereas Eg5(-/-) embryos die during early embryogenesis, prior to the implantation stage. This result shows that Eg5 is essential during early mouse development and cannot be compensated by another molecular motor.

PMID: 18474226 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

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Role of mitogen-activated protein kinase (mapk) docking sites on staufen2 protein in dendritic mrna transport.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:05:09 +0100

Role of mitogen-activated protein kinase (MAPK) docking sites on Staufen2 protein in dendritic mRNA transport.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):525-9

Authors: Nam YJ, Cheon HS, Choi YK, Kim SY, Shin EY, Kim EG, Kim HK

Although transport and subsequent translation of dendritic mRNA play an important role in neuronal synaptic plasticity, the underlying mechanisms for modulating dendritic mRNA transport are almost completely unknown. In this study, we identified and characterized an interaction between Staufen2 and mitogen-activated protein kinase (MAPK) with co-immunoprecipitation assays. Staufen2 utilized a docking (D) site to interact with ERK1/2; deleting the D-site decreased colocalization of Staufen2 with immunoreactive ERK1/2 in the cell body regions of cultured hippocampal neurons, and it reduced the amount of Staufen2-containing RNP complexes in the distal dendrites. In addition, the deletion completely abolished the depolarization-induced increase of Staufen2-containing RNP complexes. These results suggest that the MAPK pathway could modulate dendritic mRNA transport through its interaction with Staufen2.

PMID: 18492489 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Anabolic effects of pth in cyclooxygenase-2 knockout osteoblasts in vitro.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:05:05 +0100

Anabolic effects of PTH in cyclooxygenase-2 knockout osteoblasts in vitro.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):536-41

Authors: Choudhary S, Huang H, Raisz L, Pilbeam C

PTH is a potent bone anabolic agent in vivo but anabolic effects on osteoblast differentiation in vitro are difficult to demonstrate. This study examined the role of cyclooxygenase (COX)-2 and prostaglandin (PG) production in the effects of PTH on osteoblast differentiation in vitro using marrow stromal cell (MSC) and calvarial osteoblast (COB) cultures from COX-2 knockout (KO) and wild type (WT) mice. Cells were treated with PTH (10 nM) or vehicle throughout culture. Alkaline phosphatase (ALP) and osteocalcin (OCN) mRNA levels were measured at days 14 and 21, respectively, and mineralization at day 21. cAMP concentrations were measured in the presence of a phosphodiesterase inhibitor. PTH did not stimulate differentiation in cultures from WT mice but significantly increased ALP and OCN mRNA expression 6- to 7-fold in KO MSC cultures and 2- to 4-fold in KO COB cultures. PTH also increased mineralization in both KO MSC and COB cultures. Effects in KO cells were mimicked in WT MSC cultures treated with NS-398, an inhibitor of COX-2 activity. PTH increased cAMP concentrations similarly in WT and KO COBs. Differential gene responses to PTH in COX-2 KO COBs relative to WT COBs included greater fold-increases in the cAMP-mediated early response genes, c-fos and Nr4a2; increased IGF-1 mRNA expression; and decreased mRNA expression of MAP kinase phosphatase-1. PTH inhibited SOST mRNA expression 91% in COX-2 KO MSC cultures compared to 67% in WT cultures. We conclude that endogenous PGs inhibit the anabolic responses to PTH in vitro, possibly by desensitizing cAMP pathways.

PMID: 18501188 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Alpha-actinin-3 levels increase concomitantly with fast fibers in rat soleus muscle.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:59 +0100

Alpha-actinin-3 levels increase concomitantly with fast fibers in rat soleus muscle.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):584-8

Authors: Ogura Y, Naito H, Kakigi R, Ichinoseki-Sekine N, Kurosaka M, Katamoto S

Alpha (alpha)-actinin-3 is located in the skeletal muscle Z-line and forms actin-actin crosslinks. An interesting property of alpha-actinin-3 is its expression pattern, which is restricted to fast type II skeletal muscle fibers. However, little is known about the response of alpha-actinin-3 levels to changes in skeletal muscle such as fiber type transformation. This study examined alpha-actinin-3 levels in the soleus muscles of rats subjected to hindlimb unloading, which causes a slow-to-fast fiber transformation in the soleus muscle. After unloading, type II myosin heavy chain (MyHC) and fast myosin levels increased significantly (P<0.0001 for type II MyHC, P<0.005 for fast myosin). Along with these increases in fast fibers, alpha-actinin-3 expression levels increased significantly (P<0.0007) and dramatically. These results indicate that alpha-actinin-3 levels increase concomitantly with increases in skeletal muscle fast fibers.

PMID: 18501704 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

A simple and efficient method for deriving neurospheres from bone marrow stromal cells.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:54 +0100

A simple and efficient method for deriving neurospheres from bone marrow stromal cells.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):520-4

Authors: Yang Q, Mu J, Li Q, Li A, Zeng Z, Yang J, Zhang X, Tang J, Xie P

Bone marrow stromal cells (MSCs) can be differentiated into neuronal and glial-like cell types under appropriate experimental conditions. However, previously reported methods are complicated and involve the use of toxic reagents. Here, we present a simplified and nontoxic method for efficient conversion of rat MSCs into neurospheres that express the neuroectodermal marker nestin. These neurospheres can proliferate and differentiate into neuron, astrocyte, and oligodendrocyte phenotypes. We thus propose that MSCs are an emerging model cell for the treatment of a variety of neurological diseases.

PMID: 18502199 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Induction of ccl2 by simaml1 through upregulation of tweakr in melanoma cells.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:48 +0100

Induction of CCL2 by siMAML1 through upregulation of TweakR in melanoma cells.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):629-33

Authors: Kang S, Yang C, Luo R

Constitutive activation of Notch signaling was found in melanoma cells. Using siRNA specifically knocking down Notch co-activator MAML1 blocked Notch down stream transcriptional repressor Hey1 expression, significantly upregulated TweakR and CCL2 mRNA and protein expression in melanoma cell line M624. Exogenous Tweak stimulated high level CCL2 production in siMAML transfected M624 cells, which was critically dependent on Tweak-TweakR ligation. CCL2 produced by siMAML1 transfected M624 stimulated with exogenous Tweak was functional chemoattractant to activated monocytes. This study supports targeting Notch signaling using small siRNA in melanoma cells may increase immune cell recruitment and restore natural immune surveillance in tumor microenvironment.

PMID: 18503747 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

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Detection of hsv type-1 and type-2 igg using an in vitro pca based homogeneous immunoassay.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:44 +0100

Detection of HSV type-1 and type-2 IgG using an in vitro PCA based homogeneous immunoassay.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):542-6

Authors: Fry SR, Li J, de las Heras R, McCourt JA, Arel E, Kachab EH, Hazell SL, Huang CY

Enzyme immunoassays (EIAs) are widely used in the clinical laboratory and research institutes for the detection of biologically relevant analytes. Almost all EIAs are heterogeneous in nature and require multiple steps of process. In contrast, homogeneous immunoassays (HA) offer a simplified one-step approach with a number of potential advantages over contemporary heterogeneous EIAs such as higher throughput and greater clinical utility. Utilizing TEM-1 beta-lactamase as a reporter enzyme, we have developed HAs based on in vitro protein fragment complementation (PCA) for the detection of antibodies and potentially be used for antigens or other biomarkers. In this proof-of-principle study we demonstrate the successful in vitro differentiation of anti-herpes simplex virus (HSV) type-1 and type-2 Immunoglobulin G (IgG) in human serum with high sensitivity and specificity.

PMID: 18503749 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Elucidation of the role of cox-2 in liver fibrogenesis using transgenic mice.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:41 +0100

Elucidation of the role of COX-2 in liver fibrogenesis using transgenic mice.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):571-7

Authors: Yu J, Wu CW, Chu ES, Hui AY, Cheng AS, Go MY, Ching AK, Chui YL, Chan HL, Sung JJ

Hepatic COX-2 overexpression is sufficient to induce hepatitis, but its role on liver fibrosis remains unknown. We aim to elucidate possible biological effects of COX-2 in liver fibrosis using both gain-of-function and loss-of-function mouse models. COX-2 transgenic (TG) mice that specifically overexpress the human COX-2 cDNA in the liver, knockout (KO), and wild type (WT) mice were studied in two different murine fibrosis models induced by carbon tetrachloride (CCl(4)) injection or methionine and choline-deficient (MCD) diet. Liver injury was assessed by serum ALT and bilirubin levels and histological examination. Hepatic collagen content was determined by picrosirius red stain morphometry assay and quantitation of hydroxyproline. Hepatic stellate cell (HSC) activation was determined by immunohistochemical analysis of alpha-smooth muscle actin (alpha-SMA). mRNA expression of fibrogenic genes was assayed by real-time quantitative PCR. COX-2 protein was overexpressed in the liver of TG mice compared with WT littermates. CCl(4) or MCD-induced liver fibrotic injury was equally severe in TG and WT mice, as demonstrated by similar elevated levels of hepatic collagen contents. Enhanced COX-2 expression in TG liver did not affect HSC activation and fibrogenic gene expression upon CCl(4) or MCD treatment. Importantly, CCl(4)-treated KO mice did not show significant difference in liver fibrotic damage and fibrogenic gene expression compared with the WT counterparts. This is the first report on the effect of COX-2 in liver fibrosis based on genetic mouse models. The results suggest that COX-2 does not appear to mediate the development of liver fibrosis.

PMID: 18503750 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Crystal structure of hseg5 in complex with clinical candidate ck0238273 provides insight into inhibitory mechanism, potency, and specificity.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:38 +0100

Crystal structure of HsEg5 in complex with clinical candidate CK0238273 provides insight into inhibitory mechanism, potency, and specificity.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):565-70

Authors: Zhang B, Liu JF, Xu Y, Ng SC

HsEg5 is an important mitotic kinesin responsible for bipolar spindle formation at early mitosis. A rich body of evidence shows that inhibition of HsEg5 can result in mitotic arrest followed by cellular apoptosis. Recently identified HsEg5 inhibitor, CK0238273, exhibits potent antitumor activity and is currently in clinical trial. Here we report the cocrystal structure of the motor domain of HsEg5 in complex with CK0238273 at a 2.15 A resolution. Compared to the previously published HsEg5-Monastrol complex structure, CK0238273 shares the same induced-fit pocket with similar allosteric inhibitory mechanism. However, CK0238273 shows better fitting to the binding pocket with 65% increase of hydrophobic interaction area than that of Monastrol. Some unique hydrophilic interactions were also observed mostly between the phenyl ring and 8-chloro on quinazolinone of CK0238273 with ARG221 and GLY217. We believe that the combination of these interactions defines the superior potency and specificity of CK0238273.

PMID: 18503753 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Factors determining the formation and release of bioactive il-12: regulatory mechanisms for il-12p70 synthesis and inhibition.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:36 +0100

Factors determining the formation and release of bioactive IL-12: regulatory mechanisms for IL-12p70 synthesis and inhibition.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):509-12

Authors: Zhang S, Wang Q

IL-12 is an important type 1 immune activation cytokine. It is known that macrophages and dendritic cells the major cell types producing this cytokine and that these cells may release both the biologically inactive form (IL-12p40) and active form (IL-12p70) of IL-12. In this review, the latest information regarding the regulatory mechanisms governing the production of IL-12p70 by these cells is evaluated.

PMID: 18503756 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Molecular switches for pheromone release from a moth pheromone-binding protein.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:34 +0100

Molecular switches for pheromone release from a moth pheromone-binding protein.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):559-64

Authors: Xu W, Leal WS

Pheromone-binding proteins (PBPs) are involved in the uptake of pheromones from pores on the antennae, transport through an aqueous environment surrounding the olfactory receptor neurons, and fast delivery to pheromone receptors. We tested the hypothesis that a C-terminal segment and a flexible loop are involved in the release of pheromones to membrane-bound receptors. We expressed in Escherichia coli 11 mutants of the PBP from the silkworm moth, BmorPBP, taking into consideration structural differences between the forms with high and low binding affinity. The N-terminus was truncated and His-69, His-70 and His-95 at the base of a flexible loop, and a cluster of acidic residues at the C-terminus were mutated. Binding assays and circular dichroism analyses support a mechanism involving protonation of acidic residues Asp-132 and Glu-141 at the C-terminus and histidines, His-70 and His-95, in the base of a loop covering the binding pocket. The former leads to the formation of a new alpha-helix, which competes with pheromone for the binding pocket, whereas positive charge repulsion of the histidines opens the opposite side of the binding pocket.

PMID: 18503757 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

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Distinct cardiogenic preferences of two human embryonic stem cell (hesc) lines are imprinted in their proteomes in the pluripotent state.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:31 +0100

Distinct cardiogenic preferences of two human embryonic stem cell (hESC) lines are imprinted in their proteomes in the pluripotent state.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):553-8

Authors: Moore JC, Fu J, Chan YC, Lin D, Tran H, Tse HF, Li RA

Although both the H1 and HES2 human embryonic stem cell lines (NIH codes: WA01 and ES02, respectively) are capable of forming all three germ layers and their derivatives, various lines of evidence including the need to use different protocols to induce cardiac differentiation hint that they have distinct preferences to become chamber-specific heart cells. However, a direct systematic comparison has not been reported. Here we electrophysiologically demonstrated that the distributions of ventricular-, atrial- and pacemaker-like derivatives were indeed different (ratios=39:61:0 and 64:33:3 for H1 and HES2, respectively). Based on these results, we hypothesized the differences in their cardiogenic potentials are imprinted in the proteomes of undifferentiated H1 and HES2. Using multiplexing, high-resolution 2-D Differential In Gel Electrophoresis (DIGE) to minimize gel-to-gel variations that are common in conventional 2-D gels, a total of 2000 individual protein spots were separated. Of which, 55 were >2-fold differentially expressed in H1 and HES2 (p<0.05) and identified by mass spectrometery. Bioinformatic analysis of these protein differences further revealed candidate pathways that contribute to the H1 and HES2 phenotypes. We conclude that H1 and HES2 have predetermined preferences to become ventricular, atrial, and pacemaker cells due to discrete differences in their proteomes. These results improve our basic understanding of hESCs and may lead to mechanism-based methods for their directed cardiac differentiation into chamber-specific cardiomyocytes.

PMID: 18503758 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Coordinate regulation of bovine prion protein gene promoter activity by two sp1 binding site polymorphisms.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:28 +0100

Coordinate regulation of bovine prion protein gene promoter activity by two Sp1 binding site polymorphisms.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):530-5

Authors: Xue G, Sakudo A, Kim CK, Onodera T

Relationships between insertion/deletion (Ins/Del) polymorphisms of the bovine prion protein gene (PRNP) promoter and bovine spongiform encephalopathy (BSE) susceptibility have been reported. Our previous study has shown that polymorphisms of -6C-->T included in the specific protein 1 (Sp1) site in the 5'-flanking region of bovine PRNP influence the promoter activity of bovine PRNP. The present study shows that 12 and 23bp Ins/Del polymorphisms in the upstream region and an additional polymorphism (-47C-->A) in the Sp1 binding site coordinately affect the promoter activity. Reporter gene assays demonstrated that the bovine PRNP promoter containing -47A and 23bp Del/12bp Ins or 23bp Ins/12bp Ins showed lower promoter activity compared with other haplotypes (23bp Del/12bp Ins or 23bp Ins/12bp Del with -47C) or the wild-type haplotype (23bp Del/12bp Del with -47C). Furthermore, gel shift assays showed that the binding activity of Sp1 to the PRNP promoter was influenced by both polymorphisms with corresponding effects on the promoter activity. The coordinate regulation of the bovine PRNP promoter suggests the two Sp1 binding site polymorphisms control Sp1 binding to the PRNP promoter and its activity.

PMID: 18505676 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Hsp70 associates with rictor and is required for mtorc2 formation and activity.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:24 +0100

Hsp70 associates with Rictor and is required for mTORC2 formation and activity.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):578-83

Authors: Martin J, Masri J, Bernath A, Nishimura RN, Gera J

mTORC2 is a multiprotein kinase composed of mTOR, mLST8, PRR5, mSIN1 and Rictor. The complex is insensitive to rapamycin and has demonstrated functions controlling cell growth, motility, invasion and cytoskeletal assembly. mTORC2 is the major hydrophobic domain kinase which renders Akt fully active via phosphorylation on serine 473. We isolated Hsp70 as a putative Rictor interacting protein in a yeast two-hybrid assay and confirmed this interaction via co-immunoprecipitation and colocalization experiments. In cells expressing an antisense RNA targeting Hsp70, mTORC2 formation and activity were impaired. Moreover, in cells lacking Hsp70 expression, mTORC2 activity was inhibited following heat shock while controls demonstrated increased mTORC2 activity. These differential effects on mTORC2 activity were specific, in that mTORC1 did not demonstrate Hsp70-dependent alterations under these conditions. These data suggest that Hsp70 is a component of mTORC2 and is required for proper assembly and activity of the kinase both constitutively and following heat shock.

PMID: 18505677 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

The cannabinoid cb1 receptor is expressed in pancreatic delta-cells.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:21 +0100

The cannabinoid CB1 receptor is expressed in pancreatic delta-cells.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):595-600

Authors: Tharp WG, Lee YH, Maple RL, Pratley RE

Antagonists of cannabinoid CB1 receptor (CB1, CNR1) promote weight loss and decrease hyperglycemia in patients with type 2 diabetes. While the endocannabinoid system may modulate islet hormone secretion, the cell-type expressing CB1 receptor in islets has not been fully resolved. In this study, we verified receptor gene expression in rodent islets and cell lines and examined the distribution of CB1 receptor in mouse, rat, and human islets by confocal immunofluorescence (IF) microscopy. IF demonstrated CB1 receptor was present in beta-cell lines, but co-localized solely with somatostatin in the islet delta-cells of Zucker rats, C57BL/6 mice, and humans; no CB1 receptor expression was observed in alpha-, beta-, or pp-cells. Similarly, a rat somatostatinoma cell line, MSL-G2-Tu6, was found to express CB1 receptor. We also found monoacylglycerol lipase (MAGL) to be expressed in delta-cells and fatty acid amide hydrolase (FAAH) to be expressed in alpha-cells. The specific expression of CB1 in delta-cells suggests that the ECS may play a role in modulating islet hormone secretion. As there are some differences between our findings and previous reports, further studies, including detailed physiological studies of the effects of the ECS on islet function, are warranted.

PMID: 18505678 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Pi3k signaling supports amphetamine-induced dopamine efflux.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:19 +0100

PI3K signaling supports amphetamine-induced dopamine efflux.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):656-61

Authors: Lute BJ, Khoshbouei H, Saunders C, Sen N, Lin RZ, Javitch JA, Galli A

The dopamine (DA) transporter (DAT) is a major molecular target of the psychostimulant amphetamine (AMPH). AMPH, as a result of its ability to reverse DAT-mediated inward transport of DA, induces DA efflux thereby increasing extracellular DA levels. This increase is thought to underlie the behavioral effects of AMPH. We have demonstrated previously that insulin, through phosphatidylinositol 3-kinase (PI3K) signaling, regulates DA clearance by fine-tuning DAT plasma membrane expression. PI3K signaling may represent a novel mechanism for regulating DA efflux evoked by AMPH, since only active DAT at the plasma membrane can efflux DA. Here, we show in both a heterologous expression system and DA neurons that inhibition of PI3K decreases DAT cell surface expression and, as a consequence, AMPH-induced DA efflux.

PMID: 18510945 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

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Physical interaction between tbx6 and mespb is indispensable for the activation of bowline expression during xenopus somitogenesis.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:16 +0100

Physical interaction between Tbx6 and mespb is indispensable for the activation of bowline expression during Xenopus somitogenesis.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):607-12

Authors: Hitachi K, Danno H, Kondow A, Ohnuma K, Uchiyama H, Ishiura S, Kurisaki A, Asashima M

During vertebrate somitogenesis, various transcriptional factors function coordinately to determine the position of the somite boundary. Previously, we reported on the signaling crosstalk that occurs between two major transcription factors involved in somitogenesis, Tbx6 and mespb/mesp2. These factors synergistically activated the expression of a downstream gene, bowline/Ripply2, which is essential for precise formation of the somite boundary. However, the molecular mechanism underlying this synergistic effect remains unclear. In this report, we found that the Tbx6 and mespb proteins interacted physically with each other. Pulldown assays with various deletion mutants of these proteins identified the essential domains for this physical interaction. Finally, we found that interference with the physical interaction by a dominant-negative form of mespb, mespbDeltaDBD, abrogated the expression of the bowline gene during Xenopus somitogenesis. These results indicate that the appropriate expression of bowline/Ripply2 is regulated by a direct interaction between the Tbx6 and mespb proteins during Xenopus somitogenesis.

PMID: 18510946 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Template enhanced activity of lipase accommodated in siliceous mesocellular foams.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:14 +0100

Template enhanced activity of lipase accommodated in siliceous mesocellular foams.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):650-5

Authors: Zhang Y, Zhao L, Li J, Zhang H, Zheng L, Cao S, Li C

Lipases were adsorbed in siliceous mesocellular foams containing different amounts of residual template in the nanopores. It is found that the hydrolytic activities of the adsorbed lipases are increased with increasing the contents of template in the mesopores. The triacetin hydrolytic activity of the lipase adsorbed in the foam containing 46% of template can be 13 times higher than that of the lipase adsorbed in the foam without template in the nanopores, and its specific activity is about three times higher than that of the free lipase, showing the hyperactivation effect on lipase resulting from the interaction between the lipase and the surfactant in the nanopores. The immobilized lipase cross-linked with glutaraldehyde can retain up to 88% of its original activity after six hydrolysis reaction test. This work provides a new strategy to enhance the activity of immobilized lipase in mesoporous materials.

PMID: 18510948 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Activation of ppargamma negatively regulates o-glcnacylation of sp1.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:11 +0100

Activation of PPARgamma negatively regulates O-GlcNAcylation of Sp1.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):713-8

Authors: Chung SS, Kim JH, Park HS, Choi HH, Lee KW, Cho YM, Lee HK, Park KS

O-GlcNAcylation is a kind of post-translational modification and many nuclear and cytoplasmic proteins are O-GlcNAcylated. In this study, we demonstrated that thiazolidinediones (TZDs), which are used as insulin sensitizer, specifically inhibited the O-GlcNAcylation of Sp1 but did not affect the O-GlcNAcylation of the total proteins in cell culture systems and mouse models. This effect was mediated by peroxisome proliferator activated receptor gamma (PPARgamma) activation and probably by synthesis of a specific protein induced by PPARgamma activation. In addition, we demonstrated that the O-GlcNAcylation sites in the zinc-finger domain were involved in the transcriptional activation of Sp1 and that rosiglitazone, a member of TZDs, affected Sp1 transcriptional activity partially by regulating the O-GlcNAcylation level of these sites. Considering the role of hexosamine biosynthesis pathway in hyperglycemia-induced insulin resistance and Sp1 in the hyperglycemia-induced gene expression, the regulation of Sp1 O-GlcNAcylation by TZDs may help to explain the function of TZDs as a treatment for insulin resistance and diabetes.

PMID: 18513490 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Upregulation of decorin by fxr in vascular smooth muscle cells.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:09 +0100

Upregulation of decorin by FXR in vascular smooth muscle cells.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):746-51

Authors: He F, Zhang Q, Kuruba R, Gao X, Li J, Li Y, Gong W, Jiang Y, Xie W, Li S

Decorin is a member of the family of small leucine-rich proteoglycans that are present in blood vessels and synthesized by vascular smooth muscle cells (VSMCs). Decorin plays complex roles in both normal vascular physiology and the pathogenesis of various types of vascular disorders. However, the mechanisms of regulation of decorin expression in vasculature are not clearly understood. Particularly little information is available about a role of nuclear receptors in the regulation of decorin expression. In the present study, we report that activation of vascular FXR by a specific ligand resulted in upregulation of decorin at the levels of both mRNA and protein. FXR appears to induce decorin expression at a transcriptional level because (1) upregulation of decorin mRNA expression was abolished by the treatment of a transcription inhibitor, actinomycin D; and (2) decorin promoter activity was significantly increased by activation of FXR. Functional analysis of human decorin promoter identified an imperfect inverted repeat DNA motif, IR8 (-2313TGGTCAtagtgtcaTGACCT-2294), as a likely FXR-responsive element that is involved in decorin regulation.

PMID: 18514055 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Regulation of irf2 transcriptional activity by its sumoylation.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:07 +0100

Regulation of IRF2 transcriptional activity by its sumoylation.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):772-8

Authors: Han KJ, Jiang L, Shu HB

IRFs constitute a family of transcription factors involved in IFN signaling and in the development and differentiation of the immune system. IRFs activities are regulated at transcriptional level (such as IRF1) and post-translational modifications (such as IRF3 and IRF7). Here we show that IRF2 interacts with the SUMO-E3 ligase PIASy and is sumoylated in vivo. Mutagenesis analysis suggests that IRF2 contains three sumoylation sites. Sumoylation of IRF2 has no significant effects on its nuclear localization and DNA-binding activity, but increases its ability to inhibit IRF1 transcriptional activity and decreases its ability to activate the ISRE and H4 promoters. Our findings suggest that sumoylation of IRF2 regulates its transcriptional activities.

PMID: 18514056 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

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L-gln and l-ser suppress the d-galactosamine-induced il-18 expression and hepatitis.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:04 +0100

L-Gln and L-Ser suppress the D-galactosamine-induced IL-18 expression and hepatitis.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):688-90

Authors: Komano T, Egashira Y, Sanada H

D-Galactosamine (GalN) induces acute hepatitis in experimental animals and this hepatitis has been shown to be suppressed by preceding ingestion of amino acids such as Gly, L-Ser, and L-Gln. However, little is known about the mechanism of its action. The present study shows for the first time that IL-18 reduction is involved in the suppressive actions of L-Gln and L-Ser on GalN-induced hepatitis. Elevation of IL-18 mRNA expression in liver and its concentration in serum in GalN-treated rats were found to be suppressed by preceding ingestion of 10% L-Gln- or 10% L-Ser diets, and resulted in the attenuation of the increase in serum transaminase (ALT and AST) activities, indexes of hepatic injury. These results suggest that suppressive effects of some dietary amino acids on the GalN-induced hepatitis are mediated by IL-18 reduction.

PMID: 18514057 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

The rat mitochondrial ori l encodes a novel small rna resembling an ancestral trna.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:04:00 +0100

The rat mitochondrial Ori L encodes a novel small RNA resembling an ancestral tRNA.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):634-8

Authors: Yu CH, Liao JY, Zhou H, Qu LH

The RNA minihelix, a proposed tRNA precursor, exhibits tRNA-like properties. Sequence-specific RNA minihelices can inhibit cell growth probably due to their binding to the cognate tRNA and naturally occurring non-tRNA substrates for aminoacylation may serve a similar purpose. Thus far, no natural RNA minihelices have been found. In the present study, we found a novel small RNA of 32 nucleotides, which is expressed abundantly in all rat tissues tested. Distinct from all of known endogenous small RNAs, this small RNA (temporarily named as tpl-sRNA) can form an RNA minihelix containing a stem-loop domain followed by ACCA. tpl-sRNA is encoded by the light-strand replication origin (Ori L) of the rat mitochondrial genome, and the 3'-terminal CCA of tpl-sRNA is post-transcriptionally added. Moreover, tpl-sRNA is chargeable in vivo. Our study demonstrates for the first time an endogenous small RNA that resembles an ancestral tRNA and exhibits some tRNA-like properties in mammals.

PMID: 18514058 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Treadmill exercise reduces obestatin concentrations in rat fundus and small intestine.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:58 +0100

Treadmill exercise reduces obestatin concentrations in rat fundus and small intestine.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):741-5

Authors: Ghanbari-Niaki A, Jafari A, Abednazari H, Nikbakht H

Ghrelin and obestatin both are orexigenic/anorexigenic peptides which are secreted from gastrointestinal tracts (fundus submucosa cells). Obestatin is a 23 amino acid peptide recently isolated from rat stomach, is encoded by the same gene that encodes ghrelin. It has been suggested that ghrelin/obestatin stimulate growth hormone release and have opposite actions on food intake. Distribution and biological activity of obestatin and its role in energy balance were studied in rodents. The purpose of the present study was to investigate fundus and intestine obestatin concentrations and selected hormonal responses to a treadmill exercise running program. Fourteen adult Wistar male rats (12-14 weeks old, 235-250 g) were used for this study. Animals were divided into control (n=7) and training (n=7) groups. Training group was given exercise on a motor-driven treadmill at 25 m/min (0% grade) for 60 min/day, 5 days/week for 6 weeks. Rats were sacrificed 48 h after the last session of exercise fundus, small intestine, and liver were excised, immediately washed in ice-cold saline, and frozen in liquid nitrogen for determination of obestatin and ATP concentrations and liver glycogen content. Plasma was collected for glucose, growth hormone (GH), insulin, and cortisol measurements. Total obestatin concentrations were significantly (P<0.045, P<0.032, respectively) low in trained rat fundus and intestine at rest. Fundus and intestine ATP content remained unchanged. Liver glycogen content was significantly (P<0.039) higher in trained rats. Changes in plasma total obestatin, glucose, insulin, cortisol levels were not significant. Plasma GH concentrations was significantly (P<0.001) higher in trained animals when compared with control rats. The data indicate that moderate treadmill exercise was able to reduce fundus and small intestine total obestatin concentrations and this reduction was accompanied with a higher plasma GH and liver glycogen content in trained rats. Exercise training might modulate fundus and intestine total obestatin levels via an improvement of energy source and a negative feedback action of GH on this peptide.

PMID: 18514059 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Alpha-shaped dna loops induced by muts.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:54 +0100

Alpha-shaped DNA loops induced by MutS.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):618-22

Authors: Jia Y, Bi L, Li F, Chen Y, Zhang C, Zhang X

DNA mismatch repair (MMR) is critical for the maintenance of genomic stability. MMR is initiated by recognition of DNA mismatches by the protein, MutS, which subsequently recruits downstream repair factors. To better understand the mechanism by which MutS identifies and specifically binds mismatched basepairs embedded in random DNA sequences, we monitored the interaction between MutS and DNA substrates using atomic force microscopy (AFM). An alpha-shaped DNA loop formed by the interaction between MutS and DNA, which was independent of whether or not a mismatch was present in the DNA substrate. These data indicate that MutS associates with DNA non-specifically and forms an alpha-loop interaction with the DNA substrate. In this conformation, MutS is able to scan two arms of DNA simultaneously for each MutS dimer formed.

PMID: 18514060 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

A novel membrane-based anti-diabetic action of atorvastatin.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:51 +0100

A novel membrane-based anti-diabetic action of atorvastatin.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):639-43

Authors: Horvath EM, Tackett L, Elmendorf JS

We recently found that chromium picolinate (CrPic), a nutritional supplement thought to improve insulin sensitivity in individuals with impaired glucose tolerance, enhances insulin action by lowering plasma membrane (PM) cholesterol. Recent in vivo studies suggest that cholesterol-lowering statin drugs benefit insulin sensitivity in insulin-resistant patients, yet a mechanism is unknown. We report here that atorvastatin (ATV) diminished PM cholesterol by 22% (P<0.05) in 3T3-L1 adipocytes. As documented for CrPic, this small reduction in PM cholesterol enhanced insulin action. Replenishment of cholesterol mitigated the positive effects of ATV on insulin sensitivity. Co-treatment with CrPic and ATV did not amplify the extent of PM cholesterol loss or insulin sensitivity gain. In addition, analyses of insulin signal transduction suggest a non-signaling basis of both therapies. Our data reveal an unappreciated beneficial non-hepatic effect of statin action and highlight a novel mechanistic similarity between two recently recognized therapies of impaired glucose tolerance.

PMID: 18514061 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

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Direct visualization of the trimeric structure of the asic1a channel, using afm imaging.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:46 +0100

Direct visualization of the trimeric structure of the ASIC1a channel, using AFM imaging.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):752-5

Authors: Carnally SM, Dev HS, Stewart AP, Barrera NP, Van Bemmelen MX, Schild L, Henderson RM, Edwardson JM

There has been confusion about the subunit stoichiometry of the degenerin family of ion channels. Recently, a crystal structure of acid-sensing ion channel (ASIC) 1a revealed that it assembles as a trimer. Here, we used atomic force microscopy (AFM) to image unprocessed ASIC1a bound to mica. We detected a mixture of subunit monomers, dimers and trimers. In some cases, triple-subunit clusters were clearly visible, confirming the trimeric structure of the channel, and indicating that the trimer sometimes disaggregated after adhesion to the mica surface. This AFM-based technique will now enable us to determine the subunit arrangement within heteromeric ASICs.

PMID: 18514062 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Amnesiac regulates sleep onset and maintenance in drosophila melanogaster.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:44 +0100

amnesiac regulates sleep onset and maintenance in Drosophila melanogaster.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):798-803

Authors: Liu W, Guo F, Lu B, Guo A

The adenylate cyclase/cAMP signaling pathway and adult mushroom bodies (MBs) have been shown to play an important role in sleep regulation in Drosophila. The amnesiac (amn) gene, encodes a neuropeptide that is homologous with vertebrate pituitary adenylate cyclase-activating peptide (PACAP), is expressed in dorsal paired medial (DPM) neurons and is required for the middle-term memory (MTM) in flies. However, the role of amn on regulation of sleep is as yet unknown. Here we provide evidence that amn plays a major role on sleep maintenance and onset in Drosophila. Flies with the amnesiac allele, loss-of-function amn(X8) mutation, showed a fragmented sleep pattern and short sleep latency. Moreover, homeostatic regulation was disrupted in amn(X8) mutants after sleep deprivation. Sleep maintenance was also influenced by disruption of neurotransmission in DPM neurons with increased sleep bout number and decreased sleep bout length. Furthermore, age-related sleep fragmentation and initiation were inhibited in amn(X8) mutant flies. These data suggest that amn is required in initiation and maintenance of sleep.

PMID: 18514063 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Modular assembly of chimeric phi29 packaging rnas that support dna packaging.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:39 +0100

Modular assembly of chimeric phi29 packaging RNAs that support DNA packaging.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):589-94

Authors: Fang Y, Shu D, Xiao F, Guo P, Qin PZ

The bacteriophage phi29 DNA packaging motor is a protein/RNA complex that can produce strong force to condense the linear-double-stranded DNA genome into a pre-formed protein capsid. The RNA component, called the packaging RNA (pRNA), utilizes magnesium-dependent inter-molecular base-pairing interactions to form ring-shaped complexes. The pRNA is a class of non-coding RNA, interacting with phi29 motor proteins to enable DNA packaging. Here, we report a two-piece chimeric pRNA construct that is fully competent in interacting with partner pRNA to form ring-shaped complexes, in packaging DNA via the motor, and in assembling infectious phi29 virions in vitro. This is the first example of a fully functional pRNA assembled using two non-covalently interacting fragments. The results support the notion of modular pRNA architecture in the phi29 packaging motor.

PMID: 18514064 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Insight into why pyrrolidinyl peptide nucleic acid binding to dna is more stable than the dna x dna duplex.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:36 +0100

Insight into why pyrrolidinyl peptide nucleic acid binding to DNA is more stable than the DNA x DNA duplex.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):765-71

Authors: Siriwong K, Chuichay P, Saen-oon S, Suparpprom C, Vilaivan T, Hannongbua S

Molecular dynamics (MD) simulations and experimental measurements of the stability of a novel pyrrolidinyl PNA binding to DNA (PNA x DNA) in both parallel and antiparallel configurations were carried out. For comparison, simulations were also performed for the DNA x DNA duplex. The conformations of the three simulated systems were found to retain well-defined base pairing and base stacking as their starting B-like structure. A large gas-phase energy repulsion of the two negatively charged sugar-phosphate backbones of the DNA strands was found to reduce the stability of the DNA x DNA duplex significantly compared with that of the PNA x DNA complexes, especially in the antiparallel binding configuration. In addition, the antiparallel PNA x DNA was observed to be less solvated than that of the other two systems. The simulated binding free energies and the experimental melting temperatures for the three investigated systems are in good agreement, indicating that the antiparallel PNA x DNA is the most stable duplex.

PMID: 18514065 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Detection of circulating cancer cells in lung cancer patients with a panel of marker genes.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:33 +0100

Detection of circulating cancer cells in lung cancer patients with a panel of marker genes.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):756-60

Authors: Liu L, Liao GQ, He P, Zhu H, Liu PH, Qu YM, Song XM, Xu QW, Gao Q, Zhang Y, Chen WF, Yin YH

The current study was undertaken to examine the circulating cancer cells of lung cancer patients using a panel of markers and to evaluate the clinical significance of such tests. Peripheral blood mononuclear cells (PBMCs) from 134 lung cancer patients, 106 benign pulmonary disease, and 80 healthy individuals were isolated and assessed by nested reverse transcription-PCR assay for the expression of three different tumor markers, including tumor specific antigen 9 (TSA-9), Keratin 19 (KRT-19), and Pre-progastrin-releasing peptide (Pre-proGRP). Receiver operating characteristic curve (ROC) analysis showed that the combination of these markers was highly sensitive and specific in differentiating cancer patients from healthy and benign pulmonary disease controls. Of the 134 lung cancer patient blood samples, 84.3% expressed at least one tumor marker. A significant correlation was observed between the number of positive markers and disease stage and progression. Positivity of more than one marker predicted a poor response to therapy and short survival time in non-small cell lung cancer patients.

PMID: 18514066 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

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Beta1 integrins regulate chondrogenesis and rock signaling in adipose stem cells.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:31 +0100

Beta1 integrins regulate chondrogenesis and rock signaling in adipose stem cells.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):547-52

Authors: Lu ZF, Zandieh Doulabi B, Huang CL, Bank RA, Helder MN

Beta1 integrins play a controversial role during chondrogenesis. Since the maturation of chondrocytes relies on a signaling switch from cell-cell to cell-matrix interactions, we hypothesized that beta1 integrins play a different role at the earlier (mainly cell-cell interaction) from the later stage (mainly cell-matrix interaction) of chondrogenesis. Our data showed: in plain medium, sox9, collagen X, and collagen II gene expressions of ASCs were induced by beta1-integrin blockage at day 14. In chondrogenic medium, however, sox 9, sox6, and collagen II gene expression were induced at day 4 but inhibited at day 14. In addition, both beta1-integrin blockage and TGF-beta1 down-regulated Rock-1 and -2 gene expression and produced the round cells. We concluded that beta1 integrins play a more important role at the later stages than earlier stages of chondrogenesis, and that the onset of chondrogenesis promoted by beta1-integrin blockage might be through inhibiting Rock signaling.

PMID: 18514067 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Cohesin protein smc1 is a centrosomal protein.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:28 +0100

Cohesin protein SMC1 is a centrosomal protein.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):761-4

Authors: Guan J, Ekwurtzel E, Kvist U, Yuan L

Structural maintenance of chromosome protein 1 (SMC1) is well known for its roles in sister chromatid cohesion and DNA repair. In this study, we report a novel centrosomal localization of SMC1 within the cytoplasm in a variety of mammalian cell lines. We showed that SMC1 localized to centrosomes throughout the cell cycle in a microtubule-independent manner. Biochemically, SMC1 was cofractionated with the centrosomal protein gamma-tubulin in centrosomal preparation. Immunohistochemistry and immunoelectron microscopy performed on mouse tissue sections revealed that SMC1 antibody strongly labeled the base of cilia in ciliated epithelia, where basal bodies were located. Furthermore, we showed that SMC1 was associated with both centrioles of a centrosome at G0/G1 stage of the cell cycle. These results demonstrate that SMC1 is a centrosomal protein, suggesting possible involvement of SMC1 in centrosome/basal body-related functions, such as organization of dynamic arrays of microtubules and ciliary formation.

PMID: 18515072 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Vascular smooth cell proliferation in perfusion culture of porcine carotid arteries.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:25 +0100

Vascular smooth cell proliferation in perfusion culture of porcine carotid arteries.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):668-73

Authors: Liao D, Lin PH, Yao Q, Chen C

Objective of this study was to develop a novel in vitro artery culture system to study vascular smooth muscle cell (SMC) proliferation of porcine carotid arteries in response to injury, basic fibroblast growth factor (FGF2), and FGF2 conjugated with cytotoxin saporin (SAP). Perfusion-cultured porcine carotid arteries remained contractile in response to norepinephrine and relaxant to acetylcholine for up to 96 h. SMC proliferation of cultured arteries was detected by bromodeoxyuridine incorporation in both non-injured and balloon-injured arteries. In the inner layer of the vessel wall near the lumen, SMC proliferation were less than 10% in uninjured vessels, 66% in injured vessels, 80% in injured vessels with FGF2 treatment, and 5% in injured vessels with treatment of FGF2-SAP. Thus, the cultured porcine carotid arteries were viable; and the injury stimulated SMC proliferation, which was significantly enhanced by FGF2 and inhibited by FGF2-SAP.

PMID: 18515073 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Copper transport during lactation in transgenic mice expressing the human atp7a protein.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:21 +0100

Copper transport during lactation in transgenic mice expressing the human ATP7A protein.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):613-7

Authors: Llanos RM, Michalczyk AA, Freestone DJ, Currie S, Linder MC, Ackland ML, Mercer JF

Both copper transporting ATPases, ATP7A and ATP7B, are expressed in mammary epithelial cells but their role in copper delivery to milk has not been clarified. We investigated the role of ATP7A in delivery of copper to milk using transgenic mice that over-express human ATP7A. In mammary gland of transgenic mice, human ATP7A protein was 10- to 20-fold higher than in control mice, and was localized to the basolateral membrane of mammary epithelial cells in lactating mice. The copper concentration in the mammary gland of transgenic dams and stomach contents of transgenic pups was significantly reduced compared to non-transgenic mice. The mRNA levels of endogenous Atp7a, Atp7b, and Ctr1 copper transporters in the mammary gland were not altered by the expression of the ATP7A transgene, and the protein levels of Atp7b and ceruloplasmin were similar in transgenic and non-transgenic mice. These data suggest that ATP7A plays a role in removing excess copper from the mammary epithelial cells rather than supplying copper to milk.

PMID: 18515074 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Effects of parietaria judaica pollen extract on human microvascular endothelial cells.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:19 +0100

Effects of Parietaria judaica pollen extract on human microvascular endothelial cells.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):644-9

Authors: Taverna S, Flugy A, Colomba P, Barranca M, De Leo G, Alessandro R

Pollinosis from Parietaria judaica is one of the main causes of allergy in the Mediterranean area. The present study is designed to assess if P. judaica pollens contain bioactive compounds able to elicit a functional response in endothelial cells. We have demonstrated that addition of pollen extract to human lung microvascular endothelial cells (HMVEC-L) induces a modification of cell morphology, actin cytoskeletal rearrangements and an increase in endothelial cell permeability. We further showed that the treatment of endothelial cells with pollen extract causes an increase of E-selectin and VCAM-1 protein levels as well as an increase of IL-8 production. The stimulation of cell-cell adhesion molecules was paralleled by a dose-dependent increase of adhesion of polymorphonuclear cells (PMNs) to HMVEC-L monolayer. Our results suggest for the first time that pollen affect directly endothelial cells (EC) modulating critical functions related to the inflammatory response.

PMID: 18515075 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

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Hsl7 is a substrate-specific type ii protein arginine methyltransferase in yeast.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:13 +0100

Hsl7 is a substrate-specific type II protein arginine methyltransferase in yeast.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):811-5

Authors: Sayegh J, Clarke SG

The Saccharomyces cerevisiae protein Hsl7 is a regulator of the Swe1 protein kinase in cell cycle checkpoint control. Hsl7 has been previously described as a type III protein arginine methyltransferase, catalyzing the formation of omega-monomethylarginine residues on non-physiological substrates. However, we show here that Hsl7 can also display type II activity, generating symmetric dimethylarginine residues on calf thymus histone H2A. Symmetric dimethylation is only observed when enzyme and the methyl-accepting substrate were incubated for extended times. We confirmed the Hsl7-dependent formation of symmetric dimethylarginine by amino acid analysis and thin layer chromatography with wild-type and mutant recombinant enzymes expressed from both bacteria and yeast. This result is significant because no type II activity has been previously demonstrated in S. cerevisiae. We also show that Hsl7 has little or no activity on GST-GAR, a commonly used substrate for protein arginine methyltransferases, and only minimal activity on myelin basic protein. This enzyme thus may only recognize only a small subset of potential substrate proteins in yeast, in contrast to the situation with Rmt1, the major type I methyltransferase.

PMID: 18515076 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Physical and functional interactions between zip kinase and ubch5.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:10 +0100

Physical and functional interactions between ZIP kinase and UbcH5.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):708-12

Authors: Ohbayashi N, Okada K, Kawakami S, Togi S, Sato N, Ikeda O, Kamitani S, Muromoto R, Sekine Y, Kawai T, Akira S, Matsuda T

Zipper-interacting protein kinase (ZIPK) is a widely expressed serine/threonine kinase that has been implicated in cell death and transcriptional regulation, but its mechanism of regulation remains unknown. In our previous study, we showed that leukemia inhibitory factor stimulated threonine-265 phosphorylation of ZIPK, thereby leading to phosphorylation and activation of signal transducer and activator of transcription 3. Here, we identified UbcH5c as a novel ZIPK-binding partner by yeast two-hybrid screening. Importantly, we found that UbcH5c induced ubiquitination of ZIPK. Small-interfering RNA-mediated reduction of endogenous UbcH5 expression decreased ZIPK ubiquitination. Furthermore, coexpression of UbcH5c with ZIPK influenced promyelocytic leukemia protein nuclear body (PML-NB) formation. These results suggest that UbcH5 regulates ZIPK accumulation in PML-NBs by interacting with ZIPK and stimulating its ubiquitination.

PMID: 18515077 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Construction and characterization of the hmgb1 mutant as a competitive antagonist to hmgb1 induced cytokines release.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:07 +0100

Construction and characterization of the HMGB1 mutant as a competitive antagonist to HMGB1 induced cytokines release.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):703-7

Authors: Yuan Z, Chen J, Zhang Y, Peng Y

Recent studies indicate that the High Mobility Group Box-1 protein (HMGB1) acts as a potent proinflammatory cytokine that contributes to the pathogenesis of diverse inflammatory and infectious disorders. The proinflammatory cytokine activity of HMGB1 has become a therapeutic target. In this study, we cloned the cDNA encoding human HMGB1 and constructed HMGB1 mutants using a one-step opposite direction PCR. The binding of the HMGB1 mutants to THP-1 cell and the cytokine activities of these HMGB1 mutants were observed. Results showed that the HMGB1 Mut (102-105), one of the HMGB1 mutants, in which amino acids 102-105 (FFLF) were replaced with two Glys, significantly decreased the full-length HMGB1 protein induced TNF-alpha release in human monocyte cultures. The results indicate that we have developed a novel recombinant HMGB1 mutant that competitively antagonizes the proinflammatory activity of HMGB1. This may be of significant importance in providing a new anti-inflammatory strategy for the treatment of severe sepsis and other inflammatory disorders.

PMID: 18515078 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Gadd45b inhibits mkk7-induced cardiac hypertrophy and the polymorphisms of gadd45b is associated with inter-ventricular septum hypertrophy.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:03:04 +0100

GADD45B inhibits MKK7-induced cardiac hypertrophy and the polymorphisms of GADD45B is associated with inter-ventricular septum hypertrophy.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):623-8

Authors: Wang J, Wang H, Chen J, Wang X, Sun K, Wang Y, Wang J, Yang X, Song X, Xin Y, Liu Z, Hui R

Mitogen-activated protein kinase kinase 7 (MKK7) induces cardiac hypertrophy by activating the c-Juns NH2-terminal kinases (JNK). It has been reported that growth arrest and DNA-damage-inducible beta (GADD45Beta) binds to MKK7 directly and blocks its catalytic activity, mediates the inhibition of JNK signaling. However, the potential role of GADD45Beta on cardiac hypertrophy has not been investigated. In this study, we found co-infection of cardiomyocytes with adenoviral vectors expressing MKK7 and GADD45B could counteract the characteristic hypertropic responses, including an increase in cell size and elevated atrial natriuretic factor (ANP) expression which induced by overexpression of MKK7. Furthermore, siRNA-mediated knockdown of GADD45B could also cause cardiomyocytes hypertrophy. GeneChip data showed that GADD45B mRNA decreased significantly in patients with hypertrophy cardiomyopathy (HCM) compared with healthy subjects. Association study indicated that haplotype (rs2024144-rs3783501) of GADD45B affected the thickness of inter-ventricular septum in patients with HCM. Dual-luciferase assay showed that C-A haplotype displayed significantly increased transcription activity compared to T-G haplotype.

PMID: 18515079 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Localized decrease of beta-catenin contributes to the differentiation of human embryonic stem cells.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:02:59 +0100

Localized decrease of beta-catenin contributes to the differentiation of human embryonic stem cells.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):601-6

Authors: Lam H, Patel S, Wong J, Chu J, Li A, Li S

Human embryonic stem cells (hESC) are pluripotent, and can be directed to differentiate into different cell types for therapeutic applications. To expand hESCs, it is desirable to maintain hESC growth without differentiation. As hESC colonies grow, differentiated cells are often found at the periphery of the colonies, but the underlying mechanism is not well understood. Here, we utilized micropatterning techniques to pattern circular islands or strips of matrix proteins, and examined the spatial pattern of hESC renewal and differentiation. We found that micropatterned matrix restricted hESC differentiation at colony periphery but allowed hESC growth into multiple layers in the central region, which decreased hESC proliferation and induced hESC differentiation. In undifferentiated hESCs, beta-catenin primarily localized at cell-cell junctions but not in the nucleus. The amount of beta-catenin in differentiating hESCs at the periphery of colonies or in multiple layers decreased significantly at cell-cell junctions. Consistently, knocking down beta-catenin decreased Oct-4 expression in hESCs. These results indicate that localized decrease of beta-catenin contributes to the spatial pattern of differentiation in hESC colonies.

PMID: 18515080 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

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Differential display of grouper iridovirus-infected grouper cells by immunostaining.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:02:56 +0100

Differential display of grouper iridovirus-infected grouper cells by immunostaining.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):674-80

Authors: Yeh CH, Chen YS, Wu MS, Chen CW, Yuan CH, Pan KW, Chang YN, Chuang NN, Chang CY

Grouper iridovirus (GIV) is one of the most devastating infectious pathogens of aquaculture fish. When infecting a susceptible cell line, such as GK-2, GIV causes antigenic changes in host cellular proteins. To understand the host gene expression characteristics after viral infection, we developed an immunostaining method to screen differentially expressed genes of fish cells in response to GIV infection using phage display complementary DNA libraries. In total, 66 genes were identified from grouper kidney and brain cell lines. These genes are related to replication, transcription, translation, immunity, apoptosis, structure proteins, metabolism, energy, protein modification, and homeostasis. Four dynamic antigenic patterns were observed among these immunocloned genes upon GIV infection. Microarray analysis further confirmed the transcriptional patterns of 80% of the identified genes. This immunostaining screening method provides insights into a host's cellular protein response to viral infection on a translational basis.

PMID: 18519026 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Cytoplasmic expression of mouse prion protein causes severe toxicity in caenorhabditis elegans.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:02:53 +0100

Cytoplasmic expression of mouse prion protein causes severe toxicity in Caenorhabditis elegans.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):697-702

Authors: Park KW, Li L

To test if Caenorhabditis elegans could be established as a model organism for prion study, we created transgenic C. elegans expressing the cytosolic form of the mouse prion protein, MoPrP(23-231), which lacks the N-terminal signal sequence and the C-terminal glycosylphosphatidylinisotol (GPI) anchor site. We report here that transgenic worms expressing MoPrP(23-231)-CFP exhibited a wide range of distinct phenotypes: from normal growth and development, reduced mobility and development delay, complete paralysis and development arrest, to embryonic lethality. Similar levels of MoPrP(23-231)-CFP were produced in animals exhibiting these distinct phenotypes, suggesting that MoPrP(23-231)-CFP might have misfolded into distinct toxic species. In combining with the observation that mutations in PrP that affect prion pathogenesis also affect the toxic phenotypes in C. elegans, we conclude that the prion protein-folding mechanism is similar in mammals and C. elegans. Thus, C. elegans can be a useful model organism for prion research.

PMID: 18519028 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Inhibition of branching and spine maturation by repulsive guidance molecule in cultured cortical neurons.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:02:44 +0100

Inhibition of branching and spine maturation by repulsive guidance molecule in cultured cortical neurons.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):725-9

Authors: Yoshida J, Kubo T, Yamashita T

Repulsive guidance molecule (RGM) is a membrane-bound protein that was originally identified as an axon guidance molecule in the visual system. Functional studies in Xenopus and chick embryos revealed the roles of RGM in axon guidance and laminar patterning, while those in mouse embryos demonstrated its function in regulating cephalic neural tube closure. Moreover, RGM inhibition enhanced the growth of injured axons and promoted functional recovery after spinal cord injury in rats. Here, we demonstrate in vitro that RGMa, an RGM homolog, inhibits neurite growth and cortical neuron branching on mouse embryonic day 16. Further, exposure of cultured neurons to RGMa significantly reduced the number of colocalized immunoreactive clusters of synapsin 1 and PSD-95 in the spines. This RGMa-mediated inhibition of the assembly of presynaptic and postsynaptic components suggests a role of RGMa in inhibiting mature synapse formation. Thus, RGMa may negatively regulate neuronal network formation in cortical neurons.

PMID: 18519029 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)

Inhibition of nmda-induced outward currents by interleukin-1beta in hippocampal neurons.

Biochemical and Biophysical Research communications — Sat, 26 Jul 2008 09:02:37 +0100

Inhibition of NMDA-induced outward currents by interleukin-1beta in hippocampal neurons.

Biochem Biophys Res Commun. 2008 Aug 8;372(4):816-20

Authors: Zhang R, Yamada J, Hayashi Y, Wu Z, Koyama S, Nakanishi H

There is increasing evidence that a functional interaction exists between interleukin-1beta (IL-1beta) and N-methyl-D-aspartate (NMDA) receptors. The present study attempted to elucidate the effect of IL-1beta on the NMDA-induced outward currents in mechanically dissociated hippocampal neurons using a perforated patch recording technique. IL-1beta (30-100 ng/ml) inhibited the mean amplitude of the NMDA-induced outward currents that were mediated by charybdotoxin (ChTX)-sensitive Ca(2+)-activated K(+) (K(Ca)) channels. IL-1beta (100 ng/ml) also significantly increased the mean ratio of the NMDA-induced inward current amplitudes measured at the end to the beginning of a 20-s application of NMDA. In hippocampal neurons from acute slice preparations, IL-1beta significantly inhibited ChTX-sensitive K(Ca) currents induced by a depolarizing voltage-step. IL-1 receptor antagonist antagonized effects of IL-1beta. These results strongly suggest that IL-1beta increases the neuronal excitability by inhibition of ChTX-sensitive K(Ca) channels activated by Ca(2+) influx through both NMDA receptors and voltage-gated Ca(2+) channels.

PMID: 18519030 [PubMed - indexed for MEDLINE]

(Source: Biochemical and Biophysical Research communications)