Phosphoproteomic Profiling of In Vivo Signaling in Liver by the Mammalian Target of Rapamycin Complex 1 (mTORC1)

Our understanding of signal transduction networks in the physiological context of an organism remains limited, partly due to the technical challenge of identifying serine/threonine phosphorylated peptides from complex tissue samples. In the present study, we focused on signaling through the mammalian target of rapamycin (mTOR) complex 1 (mTORC1), which is at the center of a nutrient- and growth factor-responsive cell signaling network. Though studied extensively, the mechanisms involved in many mTORC1 biological functions remain poorly understood.We developed a phosphoproteomic strategy to purify, enrich and identify phosphopeptides from rat liver homogenates. Using the anticancer drug rapamycin, the only known target of which is mTORC1, we characterized signaling in liver from rats in which the complex was maximally activated by refeeding following 48 hr of starvation. Using protein and peptide fractionation methods, TiO(2) affinity purification of phosphopeptides and mass spectrometry, we reproducibly identified and quantified over four thousand phosphopeptides. Along with 5 known rapamycin-sensitive phosphorylation events, we identified 62 new rapamycin-responsive candidate phosphorylation sites. Among these were PRAS40, gephyrin, and AMP kinase 2. We observed similar proportions of increased and reduced phosphorylation in response to rapamycin. Gene ontology analysis revealed over-representation of mTOR pathway components among rapamycin-sensitive phosphopeptide candidates.In addition to identifying potential new mTORC1-mediated phosphorylation events, and providing information relevant to the biology of this signaling network, our experimental and analytical approaches indicate the feasibility of large-scale phosphoproteomic profiling of tissue samples to study physiological signaling events in vivo

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Data Consolidation from Hydroelectric Plants

This paper presents a sequence of procedures for data analysis and correction from hydroelectric plants. The procedures are based on variable data recorded by the plant. Therefore, they do not require additional financial investment in instrumentation for measurements. The proposed methodology makes use of a data manager, a queries builder, a generator of the overall efficiency function and an electronic spreadsheet. It has been applied to the data from a large Brazilian hydroelectric plant whose operation is under the coordination of the Electric System National Operator (ONS). The benefits of the data correction are analyzed using a simulator of the hydroelectric plants operation. This simulator is used to reproduce the past operation of the plant, once with official data and the next with adjusted data. The results show significant improvements in terms of quality of the data, contributing to the efficiency and reliability of the computational models in use by the energy sector in the operation planning.1363879

Vascular niche E-selectin regulates hematopoietic stem cell dormancy, self renewal and chemoresistance

The microenvironment, or niche, surrounding a stem cell largely governs its cellular fate. Two anatomical niches for hematopoietic stem cells (HSCs) have been reported in the bone marrow, but a distinct function for each of these niches remains unclear. Here we report a new role for the adhesion molecule E-selectin expressed exclusively by bone marrow endothelial cells in the vascular HSC niche. HSC quiescence was enhanced and self-renewal potential was increased in E-selectin knockout (Sele -/-) mice or after administration of an E-selectin antagonist, demonstrating that E-selectin promotes HSC proliferation and is a crucial component of the vascular niche. These effects are not mediated by canonical E-selectin ligands. Deletion or blockade of E-selectin enhances HSC survival threefold to sixfold after treatment of mice with chemotherapeutic agents or irradiation and accelerates blood neutrophil recovery. As bone marrow suppression is a severe side effect of high-dose chemotherapy, transient blockade of E-selectin is potentially a promising treatment for the protection of HSCs during chemotherapy or irradiation