bluuebunny/crossref_metadata_2025_split huggingface dataset:
Signaling networks from Gβ1 subunit to transcription factors and actin remodeling via a membrane‐located ERβ‐related protein in the rapid action of daidzein in osteoblasts
Authors: De Wilde Anne , Heberden Christine , Chaumaz Gilles , Bordat Christian , Lieberherr Michele 
Published: September 2006

AbstractAlthough estrogen replacement has been the main therapy to prevent and treat osteoporosis, there are concerns about its safety. Phytoestrogens have attracted attention to their potential impacts in osteoporosis prevention and treatment. Among phytoestrogens, the isoflavone daidzein (Dz) acts on transcription via the intracellular estrogen receptors (ER), mainly ERβ, in osteoblasts, but mimics only part of the estrogen effects. Since estradiol also exerts rapid effects in osteoblasts, we investigated the multistep processes involved in the rapid actions of low (1–100 pM) doses of daidzein. Dz bound to a membrane moiety, related to ERβ since the calcium response to Dz was blocked by an anti‐ERβ antibody directed against the C‐terminus, but not by a double‐stranded siRNA specific for ERβ. This protein was coupled to a pertussis toxin (PTX)‐sensitive Gβ1 subunit whose transducer was PLC‐β2, which triggered a rapid (5 sec) mobilization of calcium from the endoplasmic reticulum. Dz phosphorylated within 15 sec ERK1/2 whose phosphorylation involved two routes: Gβ1/PLC‐β2/PKC/c‐Raf‐1/MEK1/2 and Gβ1/PI3K/cSrc/c‐Raf‐1/MEK1/2 as shown using several inhibitors. Dz induced rapid (1 min) changes in the actin cytoskeleton via the two routes. The rapid (20 sec) phosphorylation of Elk‐1 and CREB by Dz involved Gβ1 and ERK1/2. All the processes were insensitive to the estradiol antagonist ICI 182,780. In conclusion, the rapid effects of Dz seem to be biologically relevant for the function of osteoblast in bone since the isoflavone activates transcription factors linked to early genes controlling cellular proliferation and differentiation, and modulates actin cytoskeleton which controls cell adhesion, division, or secretion. J. Cell. Physiol. 209: 786–801, 2006. © 2006 Wiley‐Liss, Inc.
N‐(4‐hydroxyphenyl)retinamide induces apoptosis in human retinal pigment epithelial cells: Retinoic acid receptors regulate apoptosis, reactive oxygen species generation, and the expression of heme oxygenase‐1 and Gadd153
Authors: Samuel William , Kutty R. Krishnan , Nagineni Sahrudaya , Vijayasarathy Camasamudram , Chandraratna Roshantha A.S. , Wiggert Barbara 
Published: September 2006

AbstractN‐(4‐hydroxyphenyl)retinamide (4HPR, fenretinide), a retinoic acid (RA) derivative and a potential cancer preventive agent, is known to exert its chemotherapeutic effects in cancer cells through induction of apoptosis. Earlier work from our laboratory has shown that relatively low concentrations of 4HPR induce neuronal differentiation of cultured human retinal pigment epithelial (ARPE‐19) cells (Chen et al., 2003, J Neurochem 84:972–981). However, at higher concentrations of 4HPR, these cells showed morphological changes including cell shrinkage and cell death. Here we demonstrate that ARPE‐19 cells treated with 4HPR exhibit a dose‐ and time‐dependent induction of apoptosis as evidenced by morphological changes, mono‐ and oligonucleosome generation, and increased activity of caspases 2 and 3. The 4HPR‐induced apoptosis as well as the activation of caspases 2 and 3 were blocked by both retinoic acid receptors (RAR) pan‐antagonists, AGN193109 and AGN194310, and by an RARα‐specific antagonist AGN194301. 4HPR treatment also increased reactive oxygen species (ROS) generation in ARPE‐19 cells in a time‐dependent manner as determined from the oxidation of 2′,7′‐dichlorofluorescin. In addition, the increase in the expression of heme oxygenase‐1 (HO‐1), a stress response protein, and the growth arrest and DNA damage‐inducible transcription factor 153 (Gadd153) in response to the ROS generation were also blocked by these receptor antagonists. Pyrrolidine dithiocarbamate (PDTC), a free‐radical scavenger, inhibited 4HPR‐induced ROS generation, the expression of its downstream mediator, Gadd153, and apoptosis in the pretreated cells. Therefore, our results, clearly demonstrate that 4HPR induces apoptosis in ARPE‐19 cells and that RARs mediate this process by regulating ROS generation as well as the expression of Gadd153 and HO‐1. J. Cell. Physiol. 209: 854–865, 2006. © 2006 Wiley‐Liss, Inc.
Self‐renewal of human embryonic stem cells is supported by a shortened G1 cell cycle phase
Authors: Becker Klaus A. , Ghule Prachi N. , Therrien Jaclyn A. , Lian Jane B. , Stein Janet L. , van Wijnen Andre J. , Stein Gary S. 
Published: September 2006

AbstractCompetency for self‐renewal of human embryonic stem (ES) cells is linked to pluripotency. However, there is a critical paucity of fundamental parameters of human ES cell division. In this study we show that human ES cells (H1 and H9; NIH‐designated WA01 and WA09) rapidly proliferate due to a very short overall cell cycle (15–16 h) compared to somatic cells (e.g., normal diploid IMR90 fibroblasts and NT‐2 teratocarcinoma cells). The human ES cell cycle maintains the four canonical cell cycle stages G1, S, G2, and M, but the duration of G1 is dramatically shortened. Bromodeoxyuridine (BrdU) incorporation and FACS analysis demonstrated that 65% of asynchronously growing human ES cells are in S phase. Immunofluorescence microscopy studies detecting BrdU labeled mitotic chromosomes, Ki67 domains, and p220NPAT containing Cajal bodies revealed that the durations of the S (∼8 h), G2 (∼4 h), and M phases (∼1 h) are similar in ES and somatic cells. We determined that human ES cells remain viable after synchronization with either nocodazole or the anti‐tumor drug Paclitaxel (taxol) and have an abbreviated G1 phase of only 2.5–3 h that is significantly shorter than in somatic cells. Molecular analyses using quantitative RT‐PCR demonstrate that human ES cells and somatic cells express similar cell cycle markers. However, among cyclins and cyclin‐dependent kinases (CDKs), we observed high mRNA levels for the G1‐related CDK4 and cyclin D2 genes. We conclude that human ES cells exhibit unique G1 cell cycle kinetics and use CDK4/cyclin D2 related mechanisms to attain competency for DNA replication. J. Cell. Physiol. 209: 883–893, 2006. © 2006 Wiley‐Liss, Inc.
Long‐term loading inhibits ERK1/2 phosphorylation and increases FGFR3 expression in MC3T3‐E1 osteoblast cells
Authors: Jackson Rebecca A. , Kumarasuriyar Arjuna , Nurcombe Victor , Cool Simon M. 
Published: September 2006

AbstractBone tissue homeostasis relies upon the ability of cells to detect and interpret extracellular signals that direct changes in tissue architecture. This study utilized a four‐point bending model to create both fluid shear and strain forces (loading) during the time‐dependent progression of MC3T3‐E1 preosteoblasts along the osteogenic lineage. Loading was shown to increase cell number, alkaline phosphatase (ALP) activity, collagen synthesis, and the mRNA expression levels of Runx2, osteocalcin (OC), osteopontin, and cyclo‐oxygenase‐2. However, mineralization in these cultures was inhibited, despite an increase in calcium accumulation, suggesting that loading may inhibit mineralization in order to increase matrix deposition. Loading also increased fibroblast growth factor receptor‐3 (FGFR3) expression coincident with an inhibition of FGFR1, FGFR4, FGF1, and extracellular signal‐related kinase (ERK)1/2 phosphorylation. To examine whether these loading‐induced changes in cell phenotype and FGFR expression could be attributed to the inhibition of ERK1/2 phosphorylation, cells were grown for 25 days in the presence of the MEK1/2 inhibitor, U0126. Significant increases in the expression of FGFR3, ALP, and OC were observed, as well as the inhibition of FGFR1, FGFR4, and FGF1. However, U0126 also increased matrix mineralization, demonstrating that inhibition of ERK1/2 phosphorylation cannot fully account for the changes observed in response to loading. In conclusion, this study demonstrates that preosteoblasts are mechanoresponsive, and that long‐term loading, whilst increasing proliferation and differentiation of preosteoblasts, inhibits matrix mineralization. In addition, the increase in FGFR3 expression suggests that it may have a role in osteoblast differentiation. J. Cell. Physiol. 209: 894–904, 2006. © 2006 Wiley‐Liss, Inc.
Human articular chondrocytes suppress in vitro proliferation of anti‐CD3 activated peripheral blood mononuclear cells
Authors: Bocelli‐Tyndall Chiara , Barbero Andrea , Candrian Christian , Ceredig Rhodri , Tyndall Alan , Martin Ivan 
Published: September 2006

AbstractObjective: To investigate whether mature human articular chondrocytes (AC) exhibit an antiproliferative effect on activated peripheral blood mononuclear cells (PBMC) and to compare this effect with other cells of mesenchymal origin. Methods: AC from healthy cadaveric cartilage were grown for different passages, in the absence (control) or presence of factors enhancing cell de‐differentiation (transforming growth factor (TGF)β1, fibroblast growth factor (FGF)‐2, and platelet derived growth factor (PDGF)bb‐TFP medium). Cell ability to suppress PBMC proliferation driven by anti‐CD3 antibody was measured by tritiated thymidine uptake following incubation for 48 h at different PBMC:AC ratios and expressed as percent of residual proliferation (RP). AC antiproliferative effect was compared to that of control dermal fibroblasts (DF) and bone marrow stromal cells (BMSC). Results: AC exhibited a cell number‐dependent antiproliferative effect. The strongest effect (up to 2% RP) was measured using the least expanded AC cultures. The use of TFP medium for AC expansion resulted in a significantly lower antiproliferative effect, in the range of that induced by BMSC (up to 18% RP). Also DF induced a marked antiproliferative effect (up to 11% RP). Conclusion: We report for the first time that human AC have a marked antiproliferative effect on anti‐CD3 stimulated PBMC, which is reduced upon culture in medium‐inducing extensive cell de‐differentiation. These results reflect the immunosuppressive properties observed for other different mesenchymal cell types and raise the question of a potential common physiological role in local tissue protection. J. Cell. Physiol. 209: 732–734, 2006. © 2006 Wiley‐Liss, Inc.
α2β1 integrin signalling enhances cyclooxygenase‐2 expression in intestinal epithelial cells
Authors: Broom Oliver Jay , Massoumi Ramin , Sjölander Anita 
Published: September 2006

AbstractInflammatory bowel diseases (IBD) are linked to an increased risk of developing colon cancer, by inflammatory mediators and alterations to the extracellular matrix (ECM). The events induced by inflammatory mediators lead to dysregulated activation and induction of inflammatory genes such as cyclooxygenase‐2 (COX‐2). COX‐2 is involved in the conversion of arachidonic acid to biologically active prostanoids and is highly upregulated in colon cancer. Since inflammation‐induced changes to the extracellular matrix could affect integrin activities, we here investigated the effect of integrin signalling on the level of COX‐2 expression in the non‐transformed intestinal epithelial cell lines, Int 407 and IEC‐6. Adhesion of these cells to a collagen I‐ or IV‐coated surface, increased surface expression of α2β1 integrin. Activation of integrins with collagen caused an increased cox‐2 promoter activity, with a subsequent increase in COX‐2 expression. The signalling cascade leading to this increased expression and promoter activity of cox‐2, involves PKCα, the small GTPase Ras and NFκB but not Erk1/2 or Src activity. The integrin‐induced increase in cellular COX‐2 activity is responsible for an elevated generation of reactive oxygen species (ROS) and increased cell migration. This signalling pathway suggests a mechanism whereby inflammation‐induced modulations of the ECM, can promote cancer transformation in the intestinal epithelial cells. J. Cell. Physiol. 209: 950–958, 2006. © 2006 Wiley‐Liss, Inc.
Acute loss of transcription factor E2F1 induces mitochondrial biogenesis in Hela cells
Authors: Goto Yuya , Hayashi Reiko , Kang Dongchon , Yoshida Kenichi 
Published: September 2006

AbstractHere, we sought to clarify the comprehensive cellular response to transcription factor E2F1 expression using short interfering RNA (siRNA)‐mediated gene silencing to examine the roles of E2F1. For this purpose, we analyzed global gene expression changes in E2F1 knockdown HeLa cells, where no changes in cell growth or apoptosis were observed. Among the identified genes, the mRNA levels of mitochondria‐encoded genes were highly elevated in E2F1 siRNA‐treated cells, but not in E2F6 siRNA‐treated cells, relative to control siRNA‐treated cells. These changes were accompanied by a significant increase in the transcription and replication of mitochondria DNA as well as the induction of nuclear‐encoded mitochondrial topoisomerase I (TOP1MT) mRNA in E2F1 knockdown cells, but not in E2F6 knockdown cells, whereas the levels of nuclear‐encoded mitochondrial transcription factor A (TFAM) mRNA and protein were unchanged, relative to the levels in control siRNA‐treated cells. Time‐course experiments demonstrated that the induction of TOP1MT coincided with the timing of E2F1 loss. In addition, E2F1 knockdown cells, but not E2F6 knockdown cells, displayed increased ATP levels along with an accumulation of cytochrome b protein. Finally, RNA interference (RNAi)‐mediated reduction in E2F1 knockdown HeLa cells, but not in E2F6 knockdown HeLa cells, resulted in increased anticancer drug sensitivity. Taken together, these data demonstrate a novel physiological aspect of E2F1 in human cancer cells, where activated mitochondrial biogenesis occurs as a consequence of the acute loss of E2F1. J. Cell. Physiol. 209: 923–934, 2006. © 2006 Wiley‐Liss, Inc.
Peroxisome proliferator‐activated receptor (PPAR)γ is expressed by human spermatozoa: Its potential role on the sperm physiology
Authors: Aquila Saveria , Bonofiglio Daniela , Gentile Mariaelena , Middea Emilia , Gabriele Sabrina , Belmonte Maria , Catalano Stefania , Pellegrino Michele , Andò Sebastiano 
Published: September 2006

AbstractThe peroxisome proliferation‐activated receptor gamma (PPARγ) is mainly expressed in the adipose tissue and integrates the control of energy, lipid, and glucose homeostasis. The present study, by means of RT‐PCR, Western blot, and immunofluorescence techniques, demonstrates that human sperm express the PPARγ. The functionality of the receptor was evidenced by 15‐deoxy‐12,14‐prostaglandin J2 (PGJ2) and rosiglitazone (BRL) PPARγ‐agonists that were tested on capacitation, acrosome reaction, and motility. Both treatments also increase AKT phosphorylations and influence glucose and lipid metabolism in sperm. The specificity of PGJ2 and BRL effects through PPARγ on human sperm was confirmed by an irreversible PPARγ antagonist, GW9662. Our findings provide evidence that human sperm express a functional PPARγ whose activation influences sperm physiology. In conclusion, the presence of PPARγ in male gamete broadens the field of action of this nuclear receptor, bringing us to look towards sperm as an endocrine mobile unit independent of the systemic regulation. J. Cell. Physiol. 209: 977–986, 2006. © 2006 Wiley‐Liss, Inc.
An early but intense cytokine production within the islets may be predictive for type 1 diabetes occurrence in the Bio Breeding (BB) rat
Authors: Papaccio Gianpaolo , Graziano Antonio , d'Aquino Riccardo , De Francesco Francesco , Puca Andrew , Pedullà Marcella 
Published: September 2006

AbstractThe Bio Breeding (BB) rat is a useful animal model of type 1 autoimmune diabetes. The aim of this study was to observe and follow the cytokine and antigenic expressions within the islets of Langerhans in young non‐diabetic, in pre‐diabetic hyperglycemic, and in overtly diabetic animals. BB rats were therefore checked at day 21 up to day 90 of life for blood glucose, insulin levels, degree of islet infiltration, expression of proinflammatory and protective cytokines and antibodies including CD4, CD8, CD25, LFA‐1, and ICAM‐1. Animals were treated with insulin as they became diabetic. We found that islets of non‐diabetic BB rats became positive to both IL‐1β and IL‐4 very early on, confirming a local but intense production of both cytokines within the islets during the initial non‐diabetic period. In addition, we observed that the production of these interleukins together with the expression levels of CD4 and CD25 are events predictive for type 1 diabetes onset in non‐diabetic BB rats, as for non‐obese diabetic (NOD) mice. In particular, the production of IL‐1β and IL‐4 during the non‐diabetic period together with the lack of enhancement of CD4 and CD25, indicating selective recruitment of activated T cells, may explain the failure of anti‐diabetic treatments in this animal model of type 1 diabetes. J. Cell. Physiol. 209: 1016–1020, 2006. © 2006 Wiley‐Liss, Inc.
High dose glucocorticoid hampers bone formation and resorption after bone marrow ablation in rat
Authors: Kondo Naoki , Tokunaga Kunihiko , Ito Tomoyuki , Arai Katsumitsu , Amizuka Norio , Minqi Li , Kitahara Hiroshi , Ito Masayuki , Naito Makoto , Shu‐Ying Jiang , Oda Kimimitsu , Murai Takehiro , Takano Reiko , Ogose Akira , Endo Naoto 
Published: September 2006

AbstractWe analyzed the effect of glucocorticoid on bone regeneration after bone marrow ablation in tibiae of 8‐week‐old rats. Methylprednisolone sodium succinate (MPSS) was injected intramuscularly at a dose of 100 mg/kg/day for 3 days. Tibiae on days 1, 3, 5, 7, 10, 12, and 14 after ablation were subjected to tartrate‐resistant acid phosphatase staining, immunohistochemistry, in situ hybridization, and transmission electron microscopy (TEM), and measurement of the volume of newly‐formed bone and the osteoclast number. MPSS significantly decreased the newly‐formed bone volume on day 7, and immature bone still remained on day 10 in the MPSS‐treated group. The volume of this bone was significantly higher than that in the control group. However, there were no differences between the groups in the osteoclast number, the expression of mRNAs for osteoblast differentiation markers, and alkaline phosphatase and cathepsin K judged by immunohistochemistry. TEM findings showed no difference in the form of osteoblasts, whereas osteoclasts in the MPSS‐treated group had less developed ruffled borders, compared to those in the control group. These results suggest that MPSS treatment affects neither the differentiation nor the shape of osteoblasts, and does not change the osteoclast number or the cathepsin K level. However, high dose MPSS inhibits both bone formation and resorption during bone regeneration after rat tibial bone marrow ablation, and inhibits ruffled border formation in osteoclasts. These data will be useful to develop bone regenerative therapies for bone diseases due to high dose steroid administration. Microsc. Res. Tech., 2006. © 2006 Wiley‐Liss, Inc.
Intact corneal stroma visualization of GFP mouse revealed by multiphoton imaging
Authors: Lo Wen , Teng Shu‐Wen , Tan Hsin‐Yuan , Kim Ki Hean , Chen Hsiao‐Ching , Lee Hsuan‐Shu , Chen Yang‐Fan , So Peter T.C. , Dong Chen‐Yuan 
Published: September 2006

AbstractThe aim of this work is to demonstrate that multiphoton microscopy is a preferred technique to investigate intact cornea structure without slicing and staining. At the micron resolution, multiphoton imaging can provide both large morphological features and detailed structure of epithelium, corneal collagen fibril bundles and keratocytes. A large area multiphoton cross‐section across an intact eye excised from a GFP mouse was obtained by a homebuilt multiphoton microscope. The broadband multiphoton fluorescence (435–700 nm) and second harmonic generation (SHG, 360–400 nm) signals were generated by the 760 nm output of a femtosecond titanium‐sapphire laser. A water immersion objective (Fluor ™, 40X, NA 0.8; Nikon) was used to facilitate imaging the curve ocular surface. The multiphoton image over entire cornea provides morphological information of epithelial cells, keratocytes, and global collagen orientation. Specifically, our planar, large area multiphoton image reveals a concentric pattern of the stroma collagen, indicative of the laminar collagen organization throughout the stroma. In addition, the green fluorescence protein (GFP) labeling contributed to fluorescence contrast of cellular area and facilitated visualizing of inactive keratocytes. Our results show that multiphoton imaging of GFP labeled mouse cornea manifests both morphological significance and structural details. The second harmonic generation imaging reveals the collagen orientation, while the multiphoton fluorescence imaging indicates morphology and distribution of cells in cornea. Our results support that multiphoton microscopy is an appropriate technology for further in vivo investigation and diagnosis of cornea. Microsc. Res. Tech., 2006. © 2006 Wiley‐Liss, Inc.
Product distributions from the OH radical‐induced oxidation of n‐pentane and isopentane (2‐methylbutane) in air
Authors: Heimann Gerald , Warneck Peter 
Published: September 2006

AbstractHydroxyl radicals, generated by photolysis of H2O2, were reacted with n‐pentane and isopentane in air in the absence of nitrogen oxides. The observed product distributions were compared with similar data derived by computer simulations, based on the known reaction mechanisms, to determine relative probabilities for hydrogen abstraction at different sites of the parent compounds and to estimate branching ratios and relative rate coefficients for cross‐combination reactions between different peroxy radicals. For n‐pentane, the distribution of the pentanols indicates probabilities for hydrogen abstraction, in percent, of q1 = 9.1 ± 0.7, q2 = 56.1 ± 1.8, and q3 = 34.8 ± 1.3, which agree with predictions based on the algorithm proposed by Atkinson. Branching ratios needed to harmonize calculated and observed product distributions are somewhat larger than, although still within the error ranges of, the values found by us previously. Comparison between experimental and calculated data confirms the isomerization and decomposition constants recently established for the three pentoxyl radical isomers. The product distribution for isopentane, which is dominated by acetone, acetaldehyde, 2‐methyl‐butan‐2‐ol, and 2‐methyl‐butan‐2‐hydroperoxide, is in harmony with the predicted oxidation mechanism. Probabilities for hydrogen abstraction from isopentane were estimated to occur to 12% at the primary, 28% at the secondary, and 60% at the tertiary sites, again in agreement with predictions based on the algorithm of Atkinson. © 2006 Wiley Periodicals, Inc. Int J Chem Kinet 38: 677–688, 2006