MedWorm: Cytology

Spheroid Formation and Neural Induction in Human Adipose-Derived Stem Cells on a Chitosan-Coated Surface

Cells Tissues Organs — Mon, 06 Feb 2012 23:00:00 +0100

Cells Tissues Organs (DOI:10.1159/000332045) (Source: Cells Tissues Organs)

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Structural analysis of proteins in living eukaryotic cells using magnetic resonance spectroscopy.

Yakugaku Zasshi : Journal of the Pharmaceutical Society of Japan — Mon, 06 Feb 2012 21:06:03 +0100

Authors: Tochio H, Shirakawa M Abstract Three-dimensional structures of proteins are often critical in understanding proteins functions. However, structures or states of proteins in cells undergo dynamical changes in response to interactions with other proteins and/or biological molecules. In addition, post-translational modification such as phosphorylation, methylation and ubiquitination can drastically change the structure and hence the properties of proteins. Therefore, to precisely correlate structure data of proteins with cell biology data, the structure information should be collected in living cells preferably at atomic level. In addition, as numerous biomolecules are packed into limited space, the concentration of macromolecules is substantially high in cells. Such crowded ...

Gene-Gene Interactions Between Interleukin-12A and Interleukin-12B with the Risk of Brain Tumor

DNA and Cell Biology — Mon, 06 Feb 2012 21:03:55 +0100

DNA and Cell Biology Feb 2012, Vol. 31, No. 2: 219-223. (Source: DNA and Cell Biology)

Bronchoscopy in Rural Areas?

Advances in Urology — Mon, 06 Feb 2012 12:46:42 +0100

Quality of bronchoscopy performed by one single pulmonologist in a scarcely populated subarctic area was compared to the guidelines provided by the British Thoracic Society (BTS). 103 patients underwent bronchoscopy. Diagnostic yield was increased to 76.6% when the first bronchoscopy was supplemented by bronchial washing fluid and brush cytology and to 86.7% (BTS guidelines >80%) after a second bronchoscopy. Median time from referral to bronchoscopy was 10 days and 8 days from positive bronchoscopy to operative referral to another hospital. 1% of patients that underwent transbronchial lung biopsy had minor complications. One pulmonologist had rate of correct diagnosis based on visible endobronchial tumors that was comparable to the rates of numerous pulmonologists at larger center...

Polo-like kinase 1 (Plk1): an Unexpected Player in DNA Replication

Cell Division — Mon, 06 Feb 2012 05:00:00 +0100

Regulation of cell cycle progression is important for the maintenance of genome integrity, and Polo-like kinases (Plks) have been identified as key regulators of this process. It is well established that Polo-like kinase 1 (Plk1) plays critical roles in mitosis but little is known about its functions at other stages of the cell cycle. Here we summarize the functions of Plk1 during DNA replication, focusing on the molecular events related to Origin Recognition Complex (ORC), the complex that is essential for the initiation of DNA replication. Within the context of Plk1 phosphorylation of Orc2, we also emphasize regulation of Orc2 in different organisms. This review is intended to provide some insight into how Plk1 coordinates DNA replication in S phase with chromosome segregation in mitosis...

Denaturation of HIV-1 Protease (PR) Monomer by Acetic Acid: Mechanistic and Trajectory Insights from Molecular Dynamics Simulations and NMR.

Cell Research — Sun, 05 Feb 2012 11:13:31 +0100

In this study, all-atom MD simulations in explicit solvent and NMR relaxation studies were performed on HIV-1 Protease (PR) in 9 M acetic acid (AcOH) (the commonly used denaturant during PR preparation). Following previous reports that denaturation proceeds via dissociation of the dimer into monomers, unfolding of the monomer by acetic acid has been explicitly investigated here. Direct visualization of the denaturation process and evidence for the mechanism of denaturation have been presented. Our simulations reveal that the denaturation of the PR monomer is caused due to direct interaction between acetic acid molecules and PR. Autocorrelation of N-H vectors calculated from the simulations have revealed that the α-helix and the surrounding β-strands represent the sensitive regions of the...

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Protocols, Toolboxes and Resource papers.

Autophagy — Sun, 05 Feb 2012 07:13:51 +0100

Authors: Klionsky DJ Abstract In the August 2009 issue of Autophagy, I indicated that we were launching a new category of article, Protocols. At that time, I noted that we would ultimately be placing these articles on a new site online. Well, that time has finally arrived (see www.landesbioscience.com/journals/autophagy/protocols/ for links to these papers). Therefore, it seems appropriate for me to briefly distinguish among three types of community-oriented papers, Protocol, Toolbox and Resource. PMID: 22301999 [PubMed - as supplied by publisher] (Source: Autophagy)

PKD at the crossroads of necrosis and autophagy.

Autophagy — Sun, 05 Feb 2012 07:13:40 +0100

Authors: Eisenberg-Lerner A, Kimchi A Abstract Reactive oxygen species (ROS) that accumulate under oxidative pressure cause severe damage to cellular components, and induce various cellular responses, including apoptosis, programmed necrosis and autophagy, depending on the cellular setting. Various studies have described ROS-induced autophagy, but only a few direct factors that regulate autophagy under oxidative stress are known to date. We have identified DAPK and PKD as such regulators by demonstrating their role in the process of autophagy in general, and specifically during oxidative stress. PKD acts as a downstream effector of DAPk in the regulation of autophagy. Furthermore, PKD functions within the autophagic network as an activator of VPS34, by associating with and phosphor...

Autophagic proteins: New facets of the oxygen paradox.

Autophagy — Sun, 05 Feb 2012 07:13:30 +0100

Authors: Jin Y, Tanaka A, Choi AM, Ryter SW Abstract Oxygen (O 2), while essential for aerobic life, can also cause metabolic toxicity through the excess generation of reactive oxygen species (ROS). Pathological changes in ROS production can originate through the partial reduction of O 2 during mitochondrial electron transport, as well as from enzymatic sources. This phenomenon, termed the oxygen paradox, has been implicated in aging and disease, and is especially evident in critical care medicine. Whereas high O 2 concentrations are utilized as a life-sustaining therapeutic for respiratory insufficiency, they in turn can cause acute lung injury. Alveolar epithelial cells represent a primary target of hyperoxia-induced lung injury. Recent studies have indicated that epithelial cell...

Maternal inheritance of mitochondrial DNA: Degradation of paternal mitochondria by allogeneic organelle autophagy, allophagy.

Autophagy — Sun, 05 Feb 2012 07:13:19 +0100

Authors: Sato M, Sato K Abstract Maternal inheritance of mitochondrial DNA (mtDNA) is generally observed in many eukaryotes. Sperm-derived paternal mitochondria and their mtDNA enter the oocyte cytoplasm upon fertilization and then normally disappear during early embryogenesis. However, the mechanism underlying this clearance of paternal mitochondria has remained largely unknown. Recently, we showed that autophagy is required for the elimination of paternal mitochondria in Caenorhabditis elegans embryos. Shortly after fertilization, autophagosomes are induced locally around the penetrated sperm components. These autophagosomes engulf paternal mitochondria, resulting in their lysosomal degradation during early embryogenesis. In autophagy-defective zygotes, paternal mitochondria and ...

Carotenoid deficiency triggers autophagy in the model green alga Chlamydomonas reinhardtii.

Autophagy — Sun, 05 Feb 2012 07:13:09 +0100

In this study we used the unicellular green alga Chlamydomonas reinhardtii to demonstrate that defects in carotenoid biosynthesis lead to the activation of autophagy, a membrane-trafficking process that participates in the recycling and degradation of damaged or toxic cellular components. Carotenoid depletion caused by either the mutation of phytoene synthase or the inhibition of phytoene desaturase by the herbicide norflurazon, resulted in a strong induction of autophagy. We found that high light transiently activates autophagy in wild-type Chlamydomonas cells as part of an adaptation response to this stress. Our results showed that a Chlamydomonas mutant defective in the synthesis of specific carotenoids that accumulate during high light stress exhibits constitutive autophagy. Moreover, ...

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A high-throughput FRET-based assay for determination of Atg4 activity.

Autophagy — Sun, 05 Feb 2012 07:13:00 +0100

In this study, a sensitive and specific method to measure the activity of two Atg4 homologs in mammalian cells, Atg4A and Atg4B, was developed using a fluorescence resonance energy transfer (FRET)-based approach. Thus LC3B and GATE-16, two substrates that could be differentially cleaved by Atg4A and Atg4B, were fused with CFP and YFP at the N- and C-terminus, respectively, allowing FRET to occur. The FRET signals decreased in proportion to the Atg4-mediated cleavage, which separated the two fluorescent proteins. This method is highly efficient for measuring the enzymatic activity and kinetics of Atg4A and Atg4B under in vitro conditions. Applications of the assay indicated that the activity of Atg4B was dependent on its catalytic cysteine and expression level, but showed little changes und...

Andrographolide sensitizes cisplatin-induced apoptosis via suppression of autophagosome-lysosome fusion in human cancer cells.

Autophagy — Sun, 05 Feb 2012 07:12:50 +0100

In this study, we sought to examine the effect of Andro on autophagy, and to evaluate whether such effect is relevant to the sensitization effect of Andro on apoptosis induced by DNA damage agents in cancer cells. First, we found that Andro is able to significantly enhance autophagic markers in various cancer cell lines, including GFP-LC3 puncta and LC3-II level. Interestingly, Andro treatment also led to marked increase of p62 protein level and addition of chloroquine (CQ) failed to further enhance either LC3-II or p62 level, indicating that Andro is likely to suppress autophagic flux at the maturation and degradation stage. Next, we provided evidence that Andro inhibits autophagosome maturation not by affecting the lysosomal function, but by impairing autophagosome-lysosome fusion. Lastl...

Enhancing lysosome biogenesis attenuates BNIP3-induced cardiomyocyte death.

Autophagy — Sun, 05 Feb 2012 07:12:40 +0100

Authors: Ma X, Godar RJ, Liu H, Diwan A Abstract Hypoxia-inducible pro-death protein BNIP3 (BCL-2/adenovirus E1B 19-kDa interacting protein 3), provokes mitochondrial permeabilization causing cardiomyocyte death in ischemia-reperfusion injury. Inhibition of autophagy accelerates BNIP3-induced cell death, by preventing removal of damaged mitochondria. We tested the hypothesis that stimulating autophagy will attenuate BNIP3-induced cardiomyocyte death. Neonatal rat cardiac myocytes (NRCMs) were adenovirally transduced with BNIP3 (or LacZ as control; at multiplicity of infection = 100); and autophagy was stimulated with rapamycin (100 nM). Cell death was assessed at 48 h. BNIP3 expression increased autophagosome abundance 8-fold and caused a 3.6-fold increase in cardiomyocyte death as...

The fibroblast growth factor signaling axis controls cardiac stem cell differentiation through regulating autophagy.

Autophagy — Sun, 05 Feb 2012 07:12:31 +0100

Authors: Zhang J, Liu J, Liu L, McKeehan WL, Wang F Abstract The fibroblast growth factor (FGF) signaling axis plays important roles in heart development. Yet, the molecular mechanism by which the FGF regulates cardiogenesis is not fully understood. Using genetically engineered mouse and in vitro cultured embryoid body (EB) models, we demonstrate that FGF signaling suppresses premature differentiation of heart progenitor cells, as well as autophagy in outflow tract (OFT) myocardiac cells. The FGF also promotes mesoderm differentiation in embryonic stem cells (ESCs) but inhibits cardiomyocyte differentiation of the mesoderm cells at later stages. Furthermore, inhibition of FGF signaling increases myocardial differentiation and autophagy in both ex vivo cultured embryos and EBs, wher...

Autophagy: A cyto-protective mechanism which prevents primary human hepatocyte apoptosis during oxidative stress.

Autophagy — Sun, 05 Feb 2012 07:12:21 +0100

Authors: Bhogal RH, Weston CJ, Curbishley SM, Adams DH, Afford SC Abstract The role of autophagy in the response of human hepatocytes to oxidative stress remains unknown. Understanding this process may have important implications for the understanding of basic liver epithelial cell biology and the responses of hepatocytes during liver disease. To address this we isolated primary hepatocytes from human liver tissue and exposed them ex vivo to hypoxia and hypoxia-reoxygenation (H-R). We showed that oxidative stress increased hepatocyte autophagy in a reactive oxygen species (ROS) and class III PtdIns3K-dependent manner. Specifically, mitochondrial ROS and NADPH oxidase were found to be key regulators of autophagy. Autophagy involved the upregulation of BECN1, LC3A, Atg7, Atg5 and Atg...

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A novel method for autophagy detection in primary cells: Impaired levels of macroautophagy in immunosenescent T cells.

Autophagy — Sun, 05 Feb 2012 07:12:11 +0100

Authors: Phadwal K, Alegre-Abarrategui J, Watson AS, Pike L, Anbalagan S, Hammond EM, Wade-Martins R, McMichael A, Klenerman P, Simon AK Abstract Autophagy is a conserved constitutive cellular process, responsible for the degradation of dysfunctional proteins and organelles. Autophagy plays a role in many diseases such as neurodegeneration and cancer; however, to date, conventional autophagy detection techniques are not suitable for clinical samples. We have developed a high throughput, statistically robust technique that quantitates autophagy in primary human leukocytes using the Image stream, an imaging flow cytometer. We validate this method on cell lines and primary cells knocked down for essential autophagy genes. Also, using this method we show that T cells have higher autoph...

Critical role of mTOR in calcineurin inhibitor-induced renal cancer progression.

Cell Cycle — Sun, 05 Feb 2012 07:06:27 +0100

Authors: Basu A, Banerjee P, Pal S Abstract Comment on: Basu A, et al. PLoS One 2011; 6:e23919. PMID: 22293493 [PubMed - as supplied by publisher] (Source: Cell Cycle)

The induction of polyploidy or apoptosis by the Aurora A kinase inhibitor MK8745 is p53-dependent.

Cell Cycle — Sun, 05 Feb 2012 07:06:17 +0100

In conclusion, our studies show p53 as a determining factor for induction of apoptosis vs. polyploidy upon inhibition of Aurora A. PMID: 22293494 [PubMed - as supplied by publisher] (Source: Cell Cycle)

Myeloid Elf‐1‐like factor stimulates adipogenic differentiation through the induction of peroxisome proliferator‐activated receptor γ expression in bone marrow

Journal of Cellular Physiology — Sat, 04 Feb 2012 13:48:58 +0100

AbstractMyeloid Elf‐1 like factor (MEF) is one of the Ets transcription factors known to regulate cell proliferation and differentiation. A previous report has shown that osteoblast‐specific MEF transgenic mice (Col1a1‐MEF‐TG mice) have low bone mass but high bone marrow adiposity. In the present study, we explored a previously unappreciated mechanism whereby MEF promotes adipogenesis in bone marrow. An adipogenic colony forming unit assay showed that bone marrow cells derived from Col1a1‐MEF‐TG mice had a higher adipogenic differentiation potential compared to those from wild‐type. The levels of adipogenic marker genes expression in 3T3L1 cells were higher when co‐cultured with Col1a1‐MEF‐ TG bone marrow cells than with wild‐type cells. MC3T3‐E1 preosteoblasts tr...

CCND1 G870A Polymorphism with Altered Cyclin D1 Transcripts Expression Is Associated with the Risk of Glioma in a Chinese Population

DNA and Cell Biology — Sat, 04 Feb 2012 04:05:10 +0100

DNA and Cell Biology , Vol. 0, No. 0. (Source: DNA and Cell Biology)

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Dynamics of expression patterns of AQP4, dystroglycan, agrin and matrix metalloproteinases in human glioblastoma

Cell and Tissue Research — Fri, 03 Feb 2012 17:53:17 +0100

Abstract In human glioblastoma, the blood–brain barrier (BBB) is disturbed. According to our concept, the glio-vascular relationships and thus the control of the BBB are essentially dependent on the polarity of astroglial cells. This polarity is characterized by the uneven distribution of the water channel protein aquaporin-4 (AQP4), dystroglycan and other molecules. Recently, we were able to show that the extracellular matrix component agrin is important for the construction and localization of the so-called orthogonal arrays of particles (OAPs), which consist in AQP4. Here, combining freeze-fracture electron microscopy, immunohistochemistry and Western blotting, we describe alterations of expression and distribution of AQP4, dystroglycan, agrin and the matrix metallopr...

Cell Biology: Push Me Pull You

Editors' Choice — Fri, 03 Feb 2012 17:34:12 +0100

A contractile ring composed of actin and myosin promotes cytokinesis—the final stage of cell division when daughter cells are physically separated from one another. The small GTPase RhoA regulates the … [Read more] (Source: Editors' Choice)

[News & Analysis] Cell Biology: Donation Spurs a Cell Observatory—And Bigger Plans

Science: Current Issue — Fri, 03 Feb 2012 17:34:11 +0100

The Broad Institute received a $32.5 million gift last week to take on one of the biggest challenges in biology: mapping the molecular "circuitry" inside several kinds of mammalian cells.Author: Jocelyn Kaiser (Source: Science: Current Issue)

Editors' Choice

Science: Current Issue — Fri, 03 Feb 2012 17:34:11 +0100

Expression and distribution of creatine transporter and creatine kinase (brain isoform) in developing and mature rat cochlear tissues

Histochemistry and Cell Biology — Fri, 03 Feb 2012 17:11:20 +0100

This study postulates that this CRT is developmentally regulated in the rat cochlea. CRT expression was measured by quantitative real-time RT-PCR and immunohistochemistry in the postnatal (P0–P14) and adult (P22–P56) rat cochlea. The maximum CRT expression was reached at the onset of hearing (P12), and this level was maintained through to adulthood. CRT immunoreactivity was strongest in the sensory inner hair cells, supporting cells and the spiral ganglion neurons. Cochlear distribution of the CK brain isoform (CKB) was also assessed by immunohistochemistry and compared with the distribution of CRT in the developing and adult cochlea. CKB was immunolocalized in the organ of Corti supporting cells, and the lateral wall tissues involved in K+ cycling, including stria vascularis and...

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Functional Characterization of Genetic Polymorphisms Identified in the Promoter Region of the Bovine PEPS Gene

DNA and Cell Biology — Fri, 03 Feb 2012 16:28:01 +0100

DNA and Cell Biology , Vol. 0, No. 0. (Source: DNA and Cell Biology)

Response to Pan's Letter

DNA and Cell Biology — Fri, 03 Feb 2012 14:44:56 +0100

DNA and Cell Biology , Vol. 0, No. 0. (Source: DNA and Cell Biology)

Functional Polymorphism Located in MMP-9 Gene Promoter Is Strongly Associated with Obesity

DNA and Cell Biology — Fri, 03 Feb 2012 14:44:50 +0100

DNA and Cell Biology , Vol. 0, No. 0. (Source: DNA and Cell Biology)

Abnormal male meiosis explains pollen sterility in the polyploid medicinal plant Pinellia ternata (Araceae).

Genetics and Molecular Research — Fri, 03 Feb 2012 11:24:05 +0100

Abnormal male meiosis explains pollen sterility in the polyploid medicinal plant Pinellia ternata (Araceae). Genet Mol Res. 2012;11(1):112-20 Authors: Liu Y, Hui RK, Deng RN, Wang JJ, Wang M, Li ZY Abstract Pinellia ternata is an important traditional Chinese medicinal plant. Its different populations in China have various ploidy levels, based on x = 13, as well as extensive aneuploid series. The microsporogenesis process was observed in specimens from three populations from three regions of Hubei Province; they were characterized by normal and abnormal meiotic divisions in pollen mother cells (PMCs) at all stages simultaneously. Meiotic abnormalities including univalents/multivalents, chromosomal laggards/bridges and micronuclei appeared in about 50% of the PMCs, together ...

Rearranging the Cell's Skeleton- 2/1/12

Johns Hopkins Medicine News — Fri, 03 Feb 2012 09:26:27 +0100

Cell biologists at Johns Hopkins have identified key steps in how certain molecules alter a cell’s skeletal shape and drive the cell’s movement. (Source: Johns Hopkins Medicine News)

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Functional Relationship of BAR/SH3 Domains of Endophilin [Membrane Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

Bin/Amphiphysin/Rvs (BAR) domain-containing proteins are essential players in the dynamics of intracellular compartments. The BAR domain is an evolutionarily conserved dimeric module characterized by a crescent-shaped structure whose intrinsic curvature, flexibility, and ability to assemble into highly ordered oligomers contribute to inducing the curvature of target membranes. Endophilins, diverging into A and B subgroups, are BAR and SH3 domain-containing proteins. They exert activities in membrane dynamic processes such as endocytosis, autophagy, mitochondrial dynamics, and permeabilization during apoptosis. Here, we report on the involvement of the third α-helix of the endophilin A BAR sequence in dimerization and identify leucine 215 as a key residue within a network of hydrophobic in...

PARP1 Poisoning Sensitizes to Topoisomerase I Inhibitors [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

In this study we evaluated the ability of the PARP inhibitor veliparib to enhance the cytotoxicity of the topoisomerase I poisons topotecan and camptothecin (CPT). Veliparib increased the cell cycle and cytotoxic effects of topotecan in multiple cell line models. Importantly, this sensitization occurred at veliparib concentrations far below those required to substantially inhibit poly(ADP-ribose) polymer synthesis and at least an order of magnitude lower than those involved in selective killing of homologous recombination-deficient cells. Further studies demonstrated that veliparib enhanced the effects of CPT in wild-type mouse embryonic fibroblasts (MEFs) but not Parp1−/− MEFs, confirming that PARP1 is the critical target for this sensitization. Importantly, parental and Parp1−/− ...

Reduced Adipose Fibrosis in 11{beta}HSD1 Deficiency [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

In obesity, rapidly expanding adipose tissue becomes hypoxic, precipitating inflammation, fibrosis, and insulin resistance. Compensatory angiogenesis may prevent these events. Mice lacking the intracellular glucocorticoid-amplifying enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1−/−) have “healthier” adipose tissue distribution and resist metabolic disease with diet-induced obesity. Here we show that adipose tissues of 11βHSD1−/− mice exhibit attenuated hypoxia, induction of hypoxia-inducible factor (HIF-1α) activation of the TGF-β/Smad3/α-smooth muscle actin (α-SMA) signaling pathway, and fibrogenesis despite similar fat accretion with diet-induced obesity. Moreover, augmented 11βHSD1−/− adipose tissue angiogenesis is associated with enhanced peroxisome pro...

miR-30a Sensitizes Tumor Cells to cis-Platinum [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

In conclusion, our results demonstrate for the first time that miR-30a can sensitize tumor cells to cis-DDP via reducing beclin 1-mediated autophagy and that increasing miR-30a level in tumor cells represents a novel approach to enhance the efficacy of chemotherapy during cancer treatment. (Source: Journal of Biological Chemistry)

Aft1 Is Required for Pericentromeric Cohesin [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

The Saccharomyces cerevisiae iron-responsive transcription factor, Aft1, has a well established role in regulating iron homeostasis through the transcriptional induction of iron-regulon genes. However, recent studies have implicated Aft1 in other cellular processes independent of iron regulation such as chromosome stability. In addition, chromosome spreads and two-hybrid data suggest that Aft1 interacts with and co-localizes with kinetochore proteins; however, the cellular implications of this have not been established. Here, we demonstrate that Aft1 associates with the kinetochore complex through Iml3. Furthermore, like Iml3, Aft1 is required for the increased association of cohesin with pericentric chromatin, which is required to resist microtubule tension, and aft1Δ cells display chrom...

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Structure and Function of Human Cdc45 [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

We report biochemical and structural data on the recombinant human Cdc45 protein, consistent with the proposed DHH family affiliation. Like the RecJ exonucleases, the human Cdc45 protein is able to bind single-stranded, but not double-stranded DNA. Small angle x-ray scattering data are consistent with a model compatible with the crystallographic structure of the RecJ/DHH family members. (Source: Journal of Biological Chemistry)

B(a)P-induced {beta}2ADR-mediated Intracellular Ca2+ Increase [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

Polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (B(a)P) are widely distributed environmental contaminants, known as potent ligands of the aryl hydrocarbon receptor (AhR). These chemicals trigger an early and transient increase of intracellular calcium concentration ([Ca2+]i), required for AhR-related effects of PAHs. The mechanisms involved in this calcium mobilization were investigated in the present study. We demonstrated that B(a)P-mediated [Ca2+]i induction was prevented in endothelial HMEC-1 cells by counteracting β2-adrenoreceptor (β2ADR) activity using pharmacological antagonists, anti-β2ADR antibodies, or siRNA-mediated knockdown of β2ADR expression; by contrast, it was strongly potentiated by β2ADR overexpression in human kidney HEK293 cells. B(a)P was shown, m...

Autophagy Suppresses IL-1{beta} Signaling via Regulation of p62 Stability [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

In this study, we identified a novel function of ATG16L1, which suppresses signaling of the pro-inflammatory cytokine IL-1β. Deletion of ATG16L1 in mouse embryonic fibroblasts significantly amplifies IL-1β signal transduction cascades. This amplification is due to elevated p62 levels in ATG16L1-deficient cells. We found that ATG16L1 regulates p62 levels via both autolysosomal and proteasomal pathways. For proteasomal degradation, we found that Cullin-3 (Cul-3) is a E3 ubiquitin ligase of p62 and that ATG16L1 is essential for neddylation of Cul-3, a step required for Cul-3 activation. Taken together our data indicate that loss-of-function of ATG16L1 results in a hyper-responsiveness to the IL-1β signaling because of the increased p62 level. (Source: Journal of Biological Chemistry)

KCa1.1 Channels in RA-FLS [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

Fibroblast-like synoviocytes (FLS) play important roles in the pathogenesis of rheumatoid arthritis (RA). Potassium channels have regulatory roles in many cell functions. We have identified the calcium- and voltage-gated KCa1.1 channel (BK, Maxi-K, Slo1, KCNMA1) as the major potassium channel expressed at the plasma membrane of FLS isolated from patients with RA (RA-FLS). We further show that blocking this channel perturbs the calcium homeostasis of the cells and inhibits the proliferation, production of VEGF, IL-8, and pro-MMP-2, and migration and invasion of RA-FLS. Our findings indicate a regulatory role of KCa1.1 channels in RA-FLS function and suggest this channel as a potential target for the treatment of RA. (Source: Journal of Biological Chemistry)

Netrin-4 in Developmental Angiogenesis [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

Netrins form a heterogeneous family of laminin-related molecules with multifunctional activities. Netrin-4, the most distant member of this family, is related to the laminin β chain and has recently been proposed to play an important role in embryonic and pathological angiogenesis. However, the data reported so far lead to the apparently contradictory conclusions supporting Netrin-4 as either a pro- or an anti-angiogenic factor. To elucidate this controversy, Netrin-4 was analyzed for a vascular activity in both cell-based models (human umbilical vein endothelial cells and human umbilical artery endothelial cells) and two zebrafish models: the wild-type AB/Tü strain and the transgenic Tg(fli1a:EGFP)y1 strain. We show that Netrin-4 is expressed in endothelial cells and in the zebrafish va...

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Direct Identification of miR-21 Targets in vSMCs [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

The bone morphogenetic protein 4 (BMP4) signaling pathway plays a critical role in the promotion and maintenance of the contractile phenotype in vascular smooth muscle cell (vSMC). Misexpression or inactivating mutations of the BMP receptor gene can lead to dedifferentiation of vSMC characterized by increased migration and proliferation that is linked to vascular proliferative disorders. Previously we demonstrated that vSMCs increase microRNA-21 (miR-21) biogenesis upon BMP4 treatment, which induces contractile gene expression by targeting programmed cell death 4 (PDCD4). To identify novel targets of miR-21 that are critical for induction of the contractile phenotype by BMP4, biotinylated miR-21 was expressed in vSMCs followed by an affinity purification of mRNAs associated with miR-21. Ne...

EGR2 in Loading-related Gene Regulation in Bone Cells [Signal Transduction]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

Of the 1,328 genes revealed by microarray to be differentially regulated by disuse, or at 8 h following a single short period of osteogenic loading of the mouse tibia, analysis by predicting associated transcription factors from annotated affinities revealed the transcription factor EGR2/Krox-20 as being more closely associated with more pathways and functions than any other. Real time quantitative PCR confirmed up-regulation of Egr2 mRNA expression by loading of the tibia in vivo. In vitro studies where strain was applied to primary cultures of mouse tibia-derived osteoblastic cells and the osteoblast UMR106 cell line also showed up-regulation of Egr2 mRNA expression. In UMR106 cells, inhibition of β1/β3 integrin function had no effect on strain-related Egr2 expression, but it was inhib...

Novel Golgi Inhibitor Shows Potent Antitumor Activity [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

ADP-ribosylation factor 1 (Arf1) plays a major role in mediating vesicular transport. Brefeldin A (BFA), a known inhibitor of the Arf1-guanine nucleotide exchange factor (GEF) interaction, is highly cytotoxic. Therefore, interaction of Arf1 with ArfGEF is an attractive target for cancer treatment. However, BFA and its derivatives have not progressed beyond the pre-clinical stage of drug development because of their poor bioavailability. Here, we aimed to identify novel inhibitors of the Arf1-ArfGEF interaction that display potent antitumor activity in vivo but with a chemical structure distinct from that of BFA. We exploited a panel of 39 cell lines (termed JFCR39) coupled with a drug sensitivity data base and COMPARE algorithm, resulting in the identification of a possible novel Arf1-ArfG...

APC Regulation of GSK-3 [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

Glycogen synthase kinase-3 (GSK-3) is essential for many signaling pathways and cellular processes. As Adenomatous Polyposis Coli (APC) functions in many of the same processes, we investigated a role for APC in the regulation of GSK-3-dependent signaling. We find that APC directly enhances GSK-3 activity. Furthermore, knockdown of APC mimics inhibition of GSK-3 by reducing phosphorylation of glycogen synthase and by activating mTOR, revealing novel roles for APC in the regulation of these enzymes. Wnt signaling inhibits GSK-3 through an unknown mechanism, and this results in both stabilization of β-catenin and activation of mTOR. We therefore hypothesized that Wnts may regulate GSK-3 by disrupting the interaction between APC and the Axin-GSK-3 complex. We find that Wnts rapidly induce APC...

C-terminal Modification of Osteopontin [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

In this study, we show that modification of the extreme C terminus of OPN plays an important regulatory role for the interaction with the αVβ3-integrin. It is demonstrated that highly phosphorylated OPN has a much reduced capability to promote cell adhesion via the αVβ3-integrin compared with lesser phosphorylated forms. The cell attachment promoted by highly phosphorylated OPN could be greatly increased by both dephosphorylation and proteolytic removal of the C terminus. Using recombinantly expressed OPN containing a tag in the N or C terminus, it is shown that a modification in the C-terminal part significantly reduces the adhesion of cells to OPN via the αVβ3-integrin, whereas modification of the N terminus does not influence the binding. The inhibited binding of the αVβ3-integr...

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CYP17 Inhibitors Regulate AR Signaling [Cell Biology]

Journal of Biological Chemistry — Fri, 03 Feb 2012 05:00:00 +0100

TOK-001 and abiraterone are potent 17-heteroarylsteroid (17-HAS) inhibitors of Cyp17, one of the rate-limiting enzymes in the biosynthesis of testosterone from cholesterol in prostate cancer cells. Nevertheless, the molecular mechanism underlying the prevention of prostate cell growth by 17-HASs still remains elusive. Here, we assess the effects of 17-HASs on androgen receptor (AR) activity in LNCaP and LAPC-4 cells. We demonstrate that both TOK-001 and abiraterone reduced AR protein and mRNA expression, and antagonized AR-dependent promoter activation induced by androgen. TOK-001, but not abiraterone, is an effective apparent competitor of the radioligand [3H]R1881 for binding to the wild type and various mutant AR (W741C, W741L) proteins. In agreement with these data, TOK-001 is a consis...

Bypass of cell cycle arrest induced by transient DNMT1 post-transcriptional silencing triggers aneuploidy in human cells

Cell Division — Fri, 03 Feb 2012 05:00:00 +0100

Conclusion: Our results suggest that DNMT1 depletion triggers a p14ARF/p53 dependent cell cycle arrest to counteract the aneuploidy induced by changes in DNA methylation. (Source: Cell Division)

Gadd45a and Gadd45b modulate innate immune functions of granulocytes and macrophages by differential regulation of p38 and JNK signaling

Journal of Cellular Physiology — Fri, 03 Feb 2012 05:00:00 +0100

This study shows that mice lacking either Gadd45a or Gadd45b are defective in the recruitment of granulocytes and macrophages to the intra‐peritoneal cavity following intra‐peritoneal administration of the bacterial cell‐wall PAMP lipopolysaccharide (LPS). Bone marrow (BM) derived granulocytes and macrophages lacking either Gadd45a or Gadd45b are shown to be impaired in their chemotactic response to LPS, as well as other inflammatory stimuli such as fMLP and IL‐8. Evidence was obtained also implicating Gadd45a and Gadd45b in other myeloid innate immune functions, including ROS production, phagocytosis, and adhesion. Gadd45a and Gadd45b activation of p38 kinase was implicated in the response of granulocytes to LPS mediated chemotaxis, whereas Gadd45a and Gadd45b curtailment of JNK a...

CIZ/NMP4 is expressed in B16 melanoma and forms a positive feedback loop with RANKL to promote migration of the melanoma cells

Journal of Cellular Physiology — Fri, 03 Feb 2012 05:00:00 +0100

AbstractTumor metastasis to bone is a serious pathological situation that causes severe pain, and deterioration in locomoter function. However, the mechanisms underlying tumor metastasis is still incompletely understood. CIZ/NMP4 is a nucleocytoplasmic shuttling protein and its roles in tumor cells have not been known. We, therefore, hypothesized the role of CIZ/NMP4 in B16 melanoma cells that metastasize to bone. CIZ/NMP4 is expressed in B16 cells. The CIZ/NMP4 expression levels are correlated to the metastatic activity in divergent types of melanoma cells. Overexpression of CIZ/NMP4increased B16 cell migration in Trans‐well assay. Conversely, siRNA‐based knockdown of CIZ/NMP4 suppressed migratory activity of these cells. As RANKL promotes metastasis of tumor cells in bone, we teste...

PI3K‐independent AKT activation in cancers: A treasure trove for novel therapeutics

Journal of Cellular Physiology — Fri, 03 Feb 2012 05:00:00 +0100

AbstractAKT/PKB serine threonine kinase, a critical signaling molecule promoting cell growth and survival pathways, is frequently dysregulated in many cancers. Although phosphatidylinositol‐3‐OH kinase (PI3K), a lipid kinase, is well characterized as a major regulator of AKT activation in response to a variety of ligands, recent studies highlight a diverse group of tyrosine (Ack1/TNK2, Src, PTK6) and serine/threonine (TBK1, IKBKE, DNAPKcs) kinases that activate AKT directly to promote its pro‐proliferative signaling functions. While some of these alternate AKT activating kinases respond to growth factors, others respond to inflammatory and genotoxic stimuli. A common theme emerging from these studies is that aberrant or hyperactivation of these alternate kinases is often associated w...

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Corrigendum

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

(Source: AJP: Cell Physiology)

Toll-like receptor deficiency worsens inflammation and lymphedema after lymphatic injury

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

In conclusion, TLR deficiency worsens tissue responses to lymphatic fluid stasis and is associated with decreased lymphangiogenesis, increased fibrosis, and reduced macrophage infiltration. These findings suggest a role for innate immune responses, including TLR signaling, in lymphatic repair and lymphedema pathogenesis. (Source: AJP: Cell Physiology)

Altered neurotransmitter release machinery in mice deficient for the deubiquitinating enzyme Usp14

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

Homozygous ataxic mice (axJ) express reduced levels of the deubiquitinating enzyme Usp14. They develop severe tremors by 2–3 wk of age, followed by hindlimb paralysis, and death by 6–8 wk. While changes in the ubiquitin proteasome system often result in the accumulation of ubiquitin protein aggregates and neuronal loss, these pathological markers are not observed in the axJ mice. Instead, defects in neurotransmission were observed in both the central and peripheral nervous systems of axJ mice. We have now identified several new alterations in peripheral neurotransmission in the axJ mice. Using the two-microelectrode voltage clamp technique on diaphragm muscles of axJ mice, we observed that under normal neurotransmitter release conditions axJ mice lacked paired-pulse facilitatio...

H-Ras isoform modulates extracellular matrix synthesis, proliferation, and migration in fibroblasts

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

Ras GTPases are ubiquitous plasma membrane transducers of extracellular stimuli. In addition to their role as oncogenes, Ras GTPases are key regulators of cell function. Each of the Ras isoforms exhibits specific modulatory activity on different cellular pathways. This has prompted researchers to determine the pathophysiological roles of each isoform. There is a proven relationship between the signaling pathways of transforming growth factor-β1 (TGF-β1) and Ras GTPases. To assess the individual role of H-Ras oncogene in basal and TGF-β1-mediated extracellular matrix (ECM) synthesis, proliferation, and migration in fibroblasts, we analyzed these processes in embryonic fibroblasts obtained from H-Ras knockout mice (H-ras–/–). We found that H-ras–/– fibr...

L-Mimosine blocks cell proliferation via upregulation of B-cell translocation gene 2 and N-myc downstream regulated gene 1 in prostate carcinoma cells

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

l-Mimosine, an iron chelator and a prolyl 4-hydroxylase inhibitor, blocks many cancer cells at the late G1 phase. B-cell translocation gene 2 (Btg2) regulates the G1/S transition phases of the cell cycle. N-myc downstream regulated gene 1 (Ndrg1) is a differentiation-inducing gene upregulated by hypoxia. We evaluated the molecular mechanisms of l-mimosine on cell cycle modulation in PC-3 and LNCaP prostate carcinoma cells. The effect of l-mimosine on cell proliferation of prostate carcinoma cells was determined by the [3H]thymidine incorporation and flow cytometry assays. l-Mimosine arrested the cell cycle at the G1 phase in PC-3 cells and at the S phase in LNCaP cells, thus attenuating cell proliferation. Immunoblot assays indicated that hypoxia and l-mimosine stabilized hypoxia-inducible...

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Estradiol attenuates high glucose-induced endothelial nitrotyrosine: role for neuronal nitric oxide synthase

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

In this study, we examined the endothelial effects of estrogen under increasing glucose levels, focusing on nitrotyrosine and peroxynitrite. Human umbilical vein endothelial cells were incubated with normal (5.5 mM) or high (15.5 or 30.5 mM) glucose before addition of estradiol (E2, 1 or 10 nM). Selective NO synthase (NOS) inhibitors were used to determine the role of specific NOS isoforms. Addition of E2 significantly reduced high glucose-induced increase in peroxynitrite and consequently, nitrotyrosine. The superoxide levels were unchanged, suggesting effects on NO generation. Inhibition of neuronal NOS (nNOS) reduced high glucose-induced nitrotyrosine, demonstrating a critical role for this enzyme. E2 increased nNOS activity under normal glucose while decreasing it under high glucose as...

A dynamic model of calcific nodule destabilization in response to monocyte- and oxidized lipid-induced matrix metalloproteinases

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

Vulnerable plaque remains clinically undetectable, and there is no accepted in vitro model. We characterize the calcific nodules produced by calcifying vascular cells (CVC) in ApoE-null mice, demonstrating increased destabilization of cultured nodules in the presence of oxidized low-density lipoprotein (oxLDL) and monocytes under pulsatile shear stress. CVC implanted in the subcutaneous space of hyperlipidemic mice produced nodules revealing features of calcific atherosclerotic plaque including a fibrous cap, cholesterol clefts, thin shoulder, lipids, and calcium mineral deposits. CVC nodules seeded in the pulsatile flow channel (avg = 23 dyn/cm2, /t = 71 dyn·cm–2·s–1) underwent deformation and destabilization. Computational fluid dynamics revealed distinct shear ...

Potential role of insulin signaling on vascular smooth muscle cell migration, proliferation, and inflammation pathways

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

To investigate the role of insulin signaling pathways in migration, proliferation, and inflammation of vascular smooth muscle cells (VSMCs), we examined the expression of active components of the phosphatidyl inositol 3 (PI-3) kinase (p-Akt) and mitogen-activated protein kinase (MAPK) (p-Erk) in primary cultures of VSMCs from human coronary arteries. VSMCs were treated in a dose-response manner with insulin (0, 1, 10, and 100 nM) for 20 min, and Akt and Erk phosphorylation were measured by Western blot analysis. In separate experiments, we evaluated the effect of 200 μM palmitate, in the presence and absence of 8 μM pioglitazone, on insulin-stimulated (100 nM for 20 min) Akt and Erk phosphorylation. The phosphorylation of Akt and Erk in VSMCs exhibited a dose dependency with a three-...

Dynamic adhesion of eryptotic erythrocytes to endothelial cells via CXCL16/SR-PSOX

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

Suicidal death of erythrocytes, or eryptosis, is characterized by cell shrinkage and cell membrane scrambling leading to phosphatidylserine exposure at the cell surface. Eryptosis is triggered by increase of cytosolic Ca2+ activity, which may result from treatment with the Ca2+ ionophore ionomycin or from energy depletion by removal of glucose. The present study tested the hypothesis that phosphatidylserine exposure at the erythrocyte surface fosters adherence to endothelial cells of the vascular wall under flow conditions at arterial shear rates and that binding of eryptotic cells to endothelial cells is mediated by the transmembrane CXC chemokine ligand 16 (CXCL16). To this end, human erythrocytes were exposed to energy depletion (for 48 h) or treated with the Ca2+ ionophore ionomycin (1...

Eryptotic red blood cell adhesion to vascular endothelium: CXCL16/SR-PSOX, a pathological amplifier. Focus on "Dynamic adhesion of eryptotic erythrocytes to endothelial cells via CXCL16/SR-PSOX"

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

(Source: AJP: Cell Physiology)

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Mitochondrial functional specialization in glycolytic and oxidative muscle fibers: tailoring the organelle for optimal function

AJP: Cell Physiology — Fri, 03 Feb 2012 05:00:00 +0100

In skeletal muscle, two major types of muscle fibers exist: slow-twitch oxidative (type I) fibers designed for low-intensity long-lasting contractions, and fast-twitch glycolytic (type II) fibers designed for high-intensity short-duration contractions. Such a wide range of capabilities has emerged through the selection across fiber types of a narrow set of molecular characteristics suitable to achieve a specific contractile phenotype. In this article we review evidence supporting the existence of distinct functional phenotypes in mitochondria from slow and fast fibers that may be required to ensure optimal muscle function. This includes differences with respect to energy substrate preferences, regulation of oxidative phosphorylation, dynamics of reactive oxygen species, handling of Ca2+, a...

Back to Stockholm for ‘metabolism, epigenetics and cell death’

Cell Death and Differentiation — Fri, 03 Feb 2012 05:00:00 +0100

Back to Stockholm for ‘metabolism, epigenetics and cell death’ Cell Death and Differentiation advance online publication, February 3, 2012. doi:10.1038/cdd.2012.6 Authors: T Panaretakis, B Joseph & B Zhivotovsky (Source: Cell Death and Differentiation)

Genetic analysis of mitochondrial protein misfolding in Drosophila melanogaster

Cell Death and Differentiation — Fri, 03 Feb 2012 05:00:00 +0100

Authors: I Pimenta de Castro, A C Costa, D Lam, R Tufi, V Fedele, N Moisoi, D Dinsdale, E Deas, S H Y Loh & L M Martins (Source: Cell Death and Differentiation)

Phosphorylation of EBP50 negatively regulates β-PIX-dependent Rac1 activity in anoikis

Cell Death and Differentiation — Fri, 03 Feb 2012 05:00:00 +0100

Phosphorylation of EBP50 negatively regulates β-PIX-dependent Rac1 activity in anoikis Cell Death and Differentiation advance online publication, February 3, 2012. doi:10.1038/cdd.2012.4 Authors: J-Y Chen, Y-Y Lin & T-S Jou (Source: Cell Death and Differentiation)

HDAC5 is required for maintenance of pericentric heterochromatin, and controls cell-cycle progression and survival of human cancer cells

Cell Death and Differentiation — Fri, 03 Feb 2012 05:00:00 +0100

Authors: P Peixoto, V Castronovo, N Matheus, C Polese, O Peulen, A Gonzalez, M Boxus, E Verdin, M Thiry, F Dequiedt & D Mottet (Source: Cell Death and Differentiation)

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Suppression of Ras/Mapk pathway signaling inhibits Myc-induced lymphomagenesis

Cell Death and Differentiation — Fri, 03 Feb 2012 05:00:00 +0100

Suppression of Ras/Mapk pathway signaling inhibits Myc-induced lymphomagenesis Cell Death and Differentiation advance online publication, February 3, 2012. doi:10.1038/cdd.2012.1 Authors: M W Gramling & C M Eischen (Source: Cell Death and Differentiation)

Gamers on 3-D mission to save world, just don't tell them they are learning cell biology

EurekAlert! - Biology — Fri, 03 Feb 2012 05:00:00 +0100

(Iowa State University) Eve Syrkin Wurtele decided the best way to get the attention of the science-deprived, gamer generation is to take the information out of a text book and put it in a medium that kids crave - video games.So she and her team developed Meta!Blast, which won honorable mention in the 2011 International Science and Engineering Visualization Challenge sponsored by the American Association for the Advancement of Science and is featured in the Feb. 3 issue of the journal Science. (Source: EurekAlert! - Biology)

SnapShot: Insulin Signaling Pathways