Characterization of the Cytochrome P450 epoxyeicosanoid pathway in non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH) is an emerging public health problem without effective therapies. Cytochrome P450 (CYP) epoxygenases metabolize arachidonic acid into bioactive epoxyeicosatrienoic acids (EETs), which have potent anti-inflammatory and protective effects. However, the functional relevance of the CYP epoxyeicosanoid metabolism pathway in the pathogenesis of NASH remains poorly understood. Our studies demonstrate that both mice with methionine-choline deficient (MCD) diet-induced NASH and humans with biopsy-confirmed NASH exhibited significantly higher free EET concentrations compared to healthy controls. Targeted disruption of Ephx2 (the gene encoding for soluble epoxide hydrolase) in mice further increased EET levels and significantly attenuated MCD diet-induced hepatic steatosis, inflammation and injury, as well as high fat diet-induced adipose tissue inflammation, systemic glucose intolerance and hepatic steatosis. Collectively, these findings suggest that dysregulation of the CYP epoxyeicosanoid pathway is a key pathological consequence of NASH in vivo, and promoting the anti-inflammatory and protective effects of EETs warrants further investigation as a novel therapeutic strategy for NASH

Loss of the Urothelial Differentiation Marker FOXA1 Is Associated with High Grade, Late Stage Bladder Cancer and Increased Tumor Proliferation

Approximately 50% of patients with muscle-invasive bladder cancer (MIBC) develop metastatic disease, which is almost invariably lethal. However, our understanding of pathways that drive aggressive behavior of MIBC is incomplete. Members of the FOXA subfamily of transcription factors are implicated in normal urogenital development and urologic malignancies. FOXA proteins are implicated in normal urothelial differentiation, but their role in bladder cancer is unknown. We examined FOXA expression in commonly used in vitro models of bladder cancer and in human bladder cancer specimens, and used a novel in vivo tissue recombination system to determine the functional significance of FOXA1 expression in bladder cancer. Logistic regression analysis showed decreased FOXA1 expression is associated with increasing tumor stage (p<0.001), and loss of FOXA1 is associated with high histologic grade (p<0.001). Also, we found that bladder urothelium that has undergone keratinizing squamous metaplasia, a precursor to the development of squamous cell carcinoma (SCC) exhibited loss of FOXA1 expression. Furthermore, 81% of cases of SCC of the bladder were negative for FOXA1 staining compared to only 40% of urothelial cell carcinomas. In addition, we showed that a subpopulation of FOXA1 negative urothelial tumor cells are highly proliferative. Knockdown of FOXA1 in RT4 bladder cancer cells resulted in increased expression of UPK1B, UPK2, UPK3A, and UPK3B, decreased E-cadherin expression and significantly increased cell proliferation, while overexpression of FOXA1 in T24 cells increased E-cadherin expression and significantly decreased cell growth and invasion. In vivo recombination of bladder cancer cells engineered to exhibit reduced FOXA1 expression with embryonic rat bladder mesenchyme and subsequent renal capsule engraftment resulted in enhanced tumor proliferation. These findings provide the first evidence linking loss of FOXA1 expression with histological subtypes of MIBC and urothelial cell proliferation, and suggest an important role for FOXA1 in the malignant phenotype of MIBC

Drying colloidal systems: laboratory models for a wide range of applications

The drying of complex fluids provides a powerful insight into phenomena that take place on time and length scales not normally accessible. An important feature of complex fluids, colloidal dispersions and polymer solutions is their high sensitivity to weak external actions. Thus, the drying of complex fluids involves a large number of physical and chemical processes. The scope of this review is the capacity to tune such systems to reproduce and explore specific properties in a physics laboratory. A wide variety of systems are presented, ranging from functional coatings, food science, cosmetology, medical diagnostics and forensics to geophysics and art

Mechanics of columnar joint formation in igneous rocks

Columnar joints are interconnected tension fractures that divide rocks into long prismatic columns. Geologists have long speculated about the formation of columnar joints in igneous rocks in order to explain the existence of surficial bands normal to column axes, the development of nearly hexagonal joint patterns, and variations in column size. Previous investigations of columnar joints generally have not utilized existing knowledge concerning fracture-surface morphology or fracture mechanics. The present research addresses the kinematics of columnar joint formation through analysis of joint-surface morphology and joint intersections; it addresses joint-growth mechanics and variable column size by using thermomechanical concepts and fracture mechanics. Each band forms when an individual crack starts at a point on the edge of the preceding crack. Cracks propagate mostly normal to column axes along the leading edges of columnar joints; systematic addition of new cracks to the edges of older ones produces overall joint growth parallel to column axes. Application of overall joint-growth criteria based on these findings indicates that downward growing joints of many lava flows grew much longer than upward growing joints, which implies very fast solidification rates in the upper portions of the flows. A thermal model consisting of water-steam convection in the upper joint set and conduction in the lower joint-set region explains this phenomenon. Polygonal joint patterns evolve from nearly tetragonal ones at flow surfaces to nearly hexagonal ones in the interiors by the gradual change of T intersections to pseudo Y intersections. Cracks form sequentially at column triple junctions, and they overshoot and cut corners of triple junctions to produce systematic changes of the joint patterns. A fracture-mechanics model based on joint-tip blunting and joint interaction indicates that joint-growth increments are relatively large when cooling rate is small, and that large growth increments produce large joint spacings, in agreement with field observations. The results of this research are relevant to formation of joints in newly formed oceanic crust and layered sedimentary rocks, to thermal history and correlation of lava flows, to engineering investigations of columnar jointed rock at two candidate sites of a nuclear waste repository, and to schemes for enhancing geothermal energy extraction by inducing thermal fractures in hot rock

Dod Modeling And Simulation Standards Vetting Process/Tool - Common &Amp; Cross-Cutting

This paper updates the Modeling and Simulation (M&S) community on the status of the M&S Project Department of Defense (DoD) Modeling and Simulation Standards Vetting Tool sponsored by the DoD M&S Steering Committee. At the Spring Simulation Interoperability Workshop (SIW), paper 06S-SIW-069 titled, Joint Automated Modeling and Simulation Standards Vetting and Repository Tool introduced the project and provided some background information. Leveraging the efforts and lessons learned from the Army, Navy and AF M&S standard vetting programs, a common vetting process and tool was created. The objective of the standards vetting process is to establish and promote common and effective M&S standards for the M&S Community. A common process and tool increases collaboration among stakeholders, encourages broad community input, minimizes duplication of effort from multiple tools and provides shared access to approved M&S Standards. The DoD Standards Vetting Tool (DSVT) is a single, integrated capability for nominating, vetting and distributing M&S standards across the DoD, Joint and all Services. The tool and adoption process for M&S Standards consists of seven stages associated to three key concepts: 1) Nominate, 2) Evaluate, and 3) Promulgate M&S Standards. The evaluation stages include technical, business and community reviews, then an independent ballot and final approval by the appropriate approval authorities. The DSVT supporting functions include 1) a set of M&S Standard\u27s informational web pages; 2) a dynamic online decision support vetting application tool; and 3) a repository system for storing and searching nominated and approved M&S standards. The DSVT supports the processes and information needed for potential submission to the Defense Standardization Program (DSP) and the DoD Information Technology Standards Registry (DISR) programs. This paper will discuss the project\u27s progress, the capabilities, and benefits and proposed way-ahead

Epoxide hydrolase 1 (EPHX1) hydrolyzes epoxyeicosanoids and impairs cardiac recovery after ischemia

Stimuli such as inflammation or hypoxia induce cytochrome P450 epoxygenase-mediated production of arachidonic acid-derived epoxyeicosatrienoic acids (EETs). EETs have cardioprotective, vasodilatory, angiogenic, anti-inflammatory, and analgesic effects, which are diminished by EET hydrolysis yielding biologically less active dihydroxyeicosatrienoic acids (DHETs). Previous in vitro assays have suggested that epoxide hydrolase 2 (EPHX2) is responsible for nearly all EET hydrolysis; EPHX1, which exhibits slow EET hydrolysis in vitro, is thought to contribute only marginally to EET hydrolysis. Using Ephx1-/-, Ephx2-/-, and Ephx1-/-/Ephx2-/- mice, we show herein that EPHX1 significantly contributes to EET hydrolysis in vivo. Disruption of Ephx1 and/or Ephx2 genes did not induce compensatory changes in expression of other Ephx genes or CYP2 family epoxygenases. Plasma levels of 8,9-, 11,12-, and 14,15-DHET were reduced by 38%, 44%, and 67% in Ephx2-/- mice compared with wild-type (WT) mice, respectively; however, plasma from Ephx1-/-/Ephx2-/- mice exhibited significantly greater reduction (100%, 99%, and 96%) of those respective DHETs. Kinetic assays and FRET experiments indicated that EPHX1 is a slow EET scavenger, but hydrolyzes EETs in a coupled reaction with P450s to limit basal EET levels. Moreover, we also found that EPHX1 activities are biologically relevant, as Ephx1-/-/Ephx2-/- hearts had significantly better postischemic functional recovery (71%) than both WT (31%) and Ephx2-/- (51%) hearts. These findings indicate that Ephx1-/-/Ephx2-/- mice are a valuable model for assessing EET-mediated effects, uncover a new paradigm for EET metabolism, and suggest that dual EPHX1 and EPHX2 inhibition may represent a therapeutic approach to manage human pathologies such as myocardial infarction