Regulation of protein kinase B and glycogen synthase kinase-3 by insulin and beta-adrenergic agonists in rat epididymal fat cells - Activation of protein kinase B by wortmannin-sensitive and -insensittve mechanisms

Previous studies using L6 myotubes have suggested that glycogen synthase kinase-3 (GSK-3) is phosphoryl ated and inactivated in response to insulin by protein kinase B (PKB, also known as Akt or RAG) (Cross, D, A, E., Alessi, D, R., Cohen, P., Andjelkovic, M., and Hemmings, B, A. (1995) Nature 378, 785-789), In the present study, marked increases in the activity of PKB have been shown to occur in insulin-treated rat epididymal fat cells with a time course compatible with the observed decrease in GSK-3 activity, Isoproterenol, acting primarily through beta(3)-adrenoreceptors, was found to decrease GSK-3 activity to a similar extent (approximately 50%) to insulin, However, unlike the effect of insulin, the inhibition of GSK by isoproterenol was not found to be sensitive to inhibition by the phosphatidylinositol 3'-kinase inhibitors, wortmannin or LY 294002, The change in GSK-3 activity brought about by isoproterenol could not be mimicked by the addition of permeant cyclic AMP analogues or forskolin to the cells, although at the concentrations used, these agents were able to stimulate lipolysis. Isoproterenol, but again not the cyclic AMP analogues, was found to increase the activity of PKB, although to a lesser extent than insulin. While wortmannin abolished the stimulation of PKB activity by insulin, it was without effect on the activation seen in response to isoproterenol, The activation of PKB by isoproterenol was not accompanied by any detectable change in the electrophoretic mobility of the protein on SDS-polyacrylamide gel electrophoresis. It would therefore appear that distinct mechanisms exist for the stimulation of PKB by insulin and isoproterenol in rat fat cells

The Paroxetine 352 Bipolar Study Revisited: Deconstruction of Corporate and Academic Misconduct

Medical ghostwriting is the practice in which pharmaceutical companies engage an outside writer to draft a manuscript submitted for publication in the names of “honorary authors,” typically academic key opinion leaders. Using newly-posted documents from paroxetine litigation, we show how the use of ghostwriters and key opinion leaders contributed to the publication of a medical journal article containing manipulated outcome data to favor the proprietary medication. The article was ghostwritten and managed by SmithKline Beecham, now GlaxoSmithKline (GSK) and Scientific Therapeutics Information, Inc. without acknowledging their contribution in the published article. The named authors with financial ties to GSK, had little or no direct involvement in the paroxetine 352 bipolar trial results and most had not reviewed any of the manuscript drafts. The manuscript was originally rejected by peer review; however, its ultimate acceptance to the American Journal of Psychiatry was facilitated by the journal editor who also had financial ties to GSK. Thus, GSK was able to take an under-powered and non-informative trial with negative results and present it as a positive marketing vehicle for off-label promotion of paroxetine for bipolar depression. In addition to the commercial spin of paroxetine efficacy, important protocol-designated safety data were unreported that may have shown paroxetine to produce potentially harmful adverse events

Identification of an N-terminal glycogen synthase kinase 3 phosphorylation site which regulates the functional localisation of polycystin-2 in vivo and in vitro

PKD2 is mutated in 15% of patients with autosomal dominant polycystic kidney disease (ADPKD). Polycystin-2 (PC2), the PKD2 protein, is a nonselective Ca2 + -permeable cation channel which may function at the cell surface and ER. Nevertheless, the factors that regulate the dynamic translocation of PC2 between the ER and other compartments are not well understood. Constitutive phosphorylation of PC2 at a single C-terminal site (Ser812) has been previously reported. Since we were unable to abolish phospholabelling of PC2 in HEK293 cells by site-directed mutagenesis of Ser812 or all 5 predicted phosphorylation sites in the C-terminus, we hypothesised that PC2 could also be phosphorylated at the N-terminus. In this paper, we report the identification of a new phosphorylation site for PC2 within its N-terminal domain (Ser76) and demonstrate that this residue is phosphorylated by glycogen synthase kinase 3 (GSK-3). The consensus recognition sequence for GSK-3 (Ser76/Ser80) is evolutionarily conserved down to lower vertebrates. In the presence of specific GSK-3 inhibitors, the lateral plasma membrane pool of endogenous PC2 redistributes into an intracellular compartment in MDCK cells without a change in primary cilia localization. Finally, co-injection of wild-type but not a S76A/S80A mutant PKD2 capped mRNA could rescue the cystic phenotype induced by an antisense morpholino oligonucleotide to pkd2 in zebrafish pronephric kidney. We conclude that surface localization of PC2 is regulated by phosphorylation at a unique GSK-3 site in its N-terminal domain in vivo and in vitro. This site is functionally significant for the maintenance of normal glomerular and tubular morphology

Local anaesthetic bupivacaine induced ovarian and prostate cancer apoptotic cell death and underlying mechanisms in vitro

Retrospective studies indicate that the use of regional anesthesia can reduce cancer recurrence after surgery which could be due to ranging from immune function preservation to direct molecular mechanisms. This study was to investigate the effects of bupivacaine on ovarian and prostate cancer cell biology and the underlying molecular mechanisms. Cell viability, proliferation and migration of ovarian carcinoma (SKOV-3) and prostate carcinoma (PC-3) were examined following treatment with bupivacaine. Cleaved caspase 3, 8 and 9, and GSK-3β, pGSK-3β(tyr216) and pGSK-3β(ser9) expression were assessed by immunofluorescence. FAS ligand neutralization, caspase and GSK-3 inhibitors and GSK-3β siRNA were applied to further explore underlying mechanisms. Clinically relevant concentrations of bupivacaine reduced cell viability and inhibited cellular proliferation and migration in both cell lines. Caspase 8 and 9 inhibition generated partial cell death reversal in SKOV-3, whilst only caspase 9 was effective in PC-3. Bupivacaine increased the phosphorylation of GSK-3β(Tyr216) in SKOV-3 but without measurable effect in PC3. GSK-3β inhibition and siRNA gene knockdown decreased bupivacaine induced cell death in SKOV-3 but not in PC3. Our data suggests that bupivacaine has direct ‘anti-cancer’ properties through the activation of intrinsic and extrinsic apoptotic pathways in ovarian cancer but only the intrinsic pathway in prostate cancer

Identification of AIP as a GSK-3 binding protein

GSK-3, a well-known serine/threonine kinase is one of the key players controlling numerous cellular and physiological processes such as protein synthesis, cell poliferation, cellular differentiation, apoptosis and microtubule dynamics. Therefore, GSK-3 phosphorylates and regulates the functions of a diverse group of substrates including many transcription factors, components regulating the cell cycles and signaling proteins. However, the mechanisms by which GSK-3 regulates the functions of many substrates specifically and selectively are not known. In order to understand the molecular basis of GSK-3 regulation and specificity, we attempt to search for novel GSK-3 binding proteins using yeast two-hybrid screening. We have identified AIP (Aurora-A Kinase Interacting Protein) as a protein that interacts with GSK-3. AIP has been reported to be a novel negative regulator of Aurora-A kinase where it might down-regulates Aurora-A kinase through proteasome dependent degradation. Our study showed that AIP is able to bind both the homologous forms of GSK-3, GSK-3a and GSK-3b in intact cells. This binding is not affected by SB216763, a specific GSK-3 inhibitor, indicating that the kinase activity of GSK-3 is not required for the interaction. AIP has the consensus motif –S-X-X-X-S- for substrate phosphorylation by GSK-3b and i sphosphorylated by GSK-3b in vitro. Our results suggest that AIPis a novel binding partner of GSK-3

GSK Contemporary – Aware: Art Fashion Identity

The Royal Academy of Arts presented GSK Contemporary 2010, the third season of contemporary art at 6 Burlington Gardens. GSK Contemporary – Aware: Art Fashion Identity focused on how artists and a number of designers examine clothing as a mechanism to communicate and reveal elements of our identity. The exhibition contained work by over 30 international contemporary artists and designers, including some newly commissioned work, and occupied the main galleries of the Royal Academy’s 6 Burlington Gardens building. As assistant curator, Daniela Hatfield assisted in the design and organisation of a series of Salon Conversations to accompany the event. Cake and conversation featured at these salons, where the audience joined practitioners from the realms of art, fashion, sociology, performance, journalism, and fashion image-making to explore themes provoked by ‘Aware’, and to discuss ways in which fashion and art are presented, consumed, understood, respected, or reviled

Diffusive behavior and the modeling of characteristic times in limit order executions

We present an empirical study of the first passage time (FPT) of order book prices needed to observe a prescribed price change Delta, the time to fill (TTF) for executed limit orders and the time to cancel (TTC) for canceled ones in a double auction market. We find that the distribution of all three quantities decays asymptotically as a power law, but that of FPT has significantly fatter tails than that of TTF. Thus a simple first passage time model cannot account for the observed TTF of limit orders. We propose that the origin of this difference is the presence of cancellations. We outline a simple model, which assumes that prices are characterized by the empirically observed distribution of the first passage time and orders are canceled randomly with lifetimes that are asymptotically power law distributed with an exponent lambda_LT. In spite of the simplifying assumptions of the model, the inclusion of cancellations is enough to account for the above observations and enables one to estimate characteristics of the cancellation strategies from empirical data.Comment: 17 pages, 9 figures, 6 tables, to appear in Quantitative Financ

Clustering based 3D level set method for volumetric cardiac segmentation

Sect.D Computer modeling and simulations : D-5Multi-slice CT (MSCT) provides dynamic three-dimensional (3D) volumetric data of the whole heart, and is an important medical imaging tool for diagnosis of cardiac diseases. Due to the large size of the dynamic data, manual identification, segmentation and tracking of various parts of the heart will be very labor intensive and inefficient. Alternatively, sophisticated image processing techniques, which require minimal user intervention, can be developed and employed to automate such tasks. In this work, we propose a semi-automatic clustering based 3D level set method to robustly segment the endocardium surface from cardiac MSCT images. The theory of level set defines a flexible and powerful surface which is capable of capturing the complex endocardium anatomical structure. A novel speed function for the level set method using a clustering algorithm is proposed to exploit the non-homogeneous blood pool intensity property by supporting a set of independent intensity samples. To define the intensity clusters for the blood pool region and the surrounding region, only a few lines drawn on the corresponding regions are required as user input. The segmentation result is a level set 3D surface in the whole volume space which can readily be constructed to form a spatial model. Our clustering based 3D level set method can also be used for segmenting other heart wall surfaces by performing appropriate initialization. By ex-tending to a 4D level set method, 4D (3D plus time) dynamic volumetric data could be readily processedpostprintProceedings of BME 2006 Biomedical Engineering Conference : biomedical engineering in education, research and industry, Hong Kong, 21-23 September 2006