Matriptase regulates c-Met mediated proliferation and invasion in inflammatory breast cancer.

The poor prognosis for patients with inflammatory breast cancer (IBC) compared to patients with other types of breast cancers emphasizes the need to better understand the molecular underpinnings of this disease with the goal of developing effective targeted therapeutics. Dysregulation of matriptase expression, an epithelial-specific member of the type II transmembrane serine protease family, has been demonstrated in many different cancer types. To date, no studies have assessed the expression and potential pro-oncogenic role of matriptase in IBC. We examined the functional relationship between matriptase and the HGF/c-MET signaling pathway in the IBC cell lines SUM149 and SUM190, and in IBC patient samples. Matriptase and c-Met proteins are localized on the surface membrane of IBC cells and their expression is strongly correlated in infiltrating cancer cells and in the cancer cells of lymphatic emboli in patient samples. Abrogation of matriptase expression by silencing with RNAi or inhibition of matriptase proteolytic activity with a synthetic inhibitor impairs the conversion of inactive pro-HGF to active HGF and subsequent c-Met-mediated signaling, leading to efficient impairment of proliferation and invasion of IBC cells. These data show the potential of matriptase inhibitors as a novel targeted therapy for IBC, and lay the groundwork for the development and testing of such drugs

The Changing Face of Winter: Lessons and Questions From the Laurentian Great Lakes

Among its many impacts, climate warming is leading to increasing winter air temperatures, decreasing ice cover extent, and changing winter precipitation patterns over the Laurentian Great Lakes and their watershed. Understanding and predicting the consequences of these changes is impeded by a shortage of winter-period studies on most aspects of Great Lake limnology. In this review, we summarize what is known about the Great Lakes during their 3–6 months of winter and identify key open questions about the physics, chemistry, and biology of the Laurentian Great Lakes and other large, seasonally frozen lakes. Existing studies show that winter conditions have important effects on physical, biogeochemical, and biological processes, not only during winter but in subsequent seasons as well. Ice cover, the extent of which fluctuates dramatically among years and the five lakes, emerges as a key variable that controls many aspects of the functioning of the Great Lakes ecosystem. Studies on the properties and formation of Great Lakes ice, its effect on vertical and horizontal mixing, light conditions, and biota, along with winter measurements of fundamental state and rate parameters in the lakes and their watersheds are needed to close the winter knowledge gap. Overcoming the formidable logistical challenges of winter research on these large and dynamic ecosystems may require investment in new, specialized research infrastructure. Perhaps more importantly, it will demand broader recognition of the value of such work and collaboration between physicists, geochemists, and biologists working on the world\u27s seasonally freezing lakes and seas

Mitochondrial response in a toddler-aged swine model following diffuse non-impact traumatic brain injury.

Traumatic brain injury (TBI) is an important health problem, and a leading cause of death in children worldwide. Mitochondrial dysfunction is a critical component of the secondary TBI cascades. The response of mitochondria in the pediatric brain to injury has limited investigation, despite evidence that developing brain's response differs from the adult, especially in diffuse non-impact TBI. We perform a detailed evaluation of mitochondrial bioenergetics using high-resolution respirometry in a swine model of diffuse TBI (rapid non-impact rotational injury: RNR), and examined the cortex and hippocampus. A substrate-uncoupler-inhibitor-titration protocol examined the role of the individual complexes as well as the uncoupled maximal respiration. Respiration per mg of tissue was also related to citrate synthase activity (CS) as an attempt to control for variability in mitochondrial content following injury. Diffuse RNR stimulated increased complex II-driven respiration relative to mitochondrial content in the hippocampus compared to shams. LEAK (State 4O) respiration was increased in both hippocampal and cortical tissue, with decreased respiratory ratios of convergent oxidative phosphorylation through complex I and II, compared to sham animals, indicating uncoupling of oxidative phosphorylation at 24h. The study suggests that proportionately, complex I contribution to convergent mitochondrial respiration was reduced in the hippocampus after RNR, with a simultaneous increase in complex-II driven respiration. In addition, mitochondrial respiration 24h after diffuse TBI that varies by location within the brain. Finally, we conclude that significant uncoupling of oxidative phosphorylation and alterations in convergent respiration through complex I- and complex II-driven respiration reveals therapeutic opportunities for the injured at-risk pediatric brain

Mitochondrial bioenergetic alterations after focal traumatic brain injury in the immature brain.

Traumatic brain injury (TBI) is one of the leading causes of death in children worldwide. Emerging evidence suggests that alterations in mitochondrial function are critical components of secondary injury cascade initiated by TBI that propogates neurodegeneration and limits neuroregeneration. Unfortunately, there is very little known about the cerebral mitochondrial bioenergetic response from the immature brain triggered by traumatic biomechanical forces. Therefore, the objective of this study was to perform a detailed evaluation of mitochondrial bioenergetics using high-resolution respirometry in a high-fidelity large animal model of focal controlled cortical impact injury (CCI) 24h post-injury. This novel approach is directed at analyzing dysfunction in electron transport, ADP phosphorylation and leak respiration to provide insight into potential mechanisms and possible interventions for mitochondrial dysfunction in the immature brain in focal TBI by delineating targets within the electron transport system (ETS). Development and application of these methodologies have several advantages, and adds to the interpretation of previously reported techniques, by having the added benefit that any toxins or neurometabolites present in the ex-vivo samples are not removed during the mitochondrial isolation process, and simulates the in situ tricarboxylic acid (TCA) cycle by maximizing key substrates for convergent flow of electrons through both complexes I and II. To investigate alterations in mitochondrial function after CCI, ipsilateral tissue near the focal impact site and tissue from the corresponding contralateral side were examined. Respiration per mg of tissue was also related to citrate synthase activity (CS) and calculated flux control ratios (FCR), as an attempt to control for variability in mitochondrial content. Our biochemical analysis of complex interdependent pathways of electron flow through the electron transport system, by most measures, reveals a bilateral decrease in complex I-driven respiration and an increase in complex II-driven respiration 24h after focal TBI. These alterations in convergent electron flow though both complex I and II-driven respiration resulted in significantly lower maximal coupled and uncoupled respiration in the ipsilateral tissue compared to the contralateral side, for all measures. Surprisingly, increases in complex II and complex IV activities were most pronounced in the contralateral side of the brain from the focal injury, and where oxidative phosphorylation was increased significantly compared to sham values. We conclude that 24h after focal TBI in the immature brain, there are significant alterations in cerebral mitochondrial bioenergetics, with pronounced increases in complex II and complex IV respiration in the contralateral hemisphere. These alterations in mitochondrial bioenergetics present multiple targets for therapeutic intervention to limit secondary brain injury and support recovery

Detailed Velocity and Heat Transfer Measurements in an Advanced Gas Turbine Vane Insert Using Magnetic Resonance Velocimetry and Infrared Thermometry

This work reports the results of paired experiments for a complex internal cooling flow within a gas turbine vane using magnetic resonance velocimetry (MRV) and steady-state infrared (IR) thermometry. A scaled model of the leading edge insert for a gas turbine vane with multi-pass impingement was designed, built using stereolithography fabrication methods, and tested using MRV techniques to collect a three-dimensional, three-component velocity field data set for a fully turbulent test case. Stagnation and recirculation zones were identified and assessed in terms of impact on potential cooling performance. A paired experiment employed an IR camera to measure the temperature profile data of a thin, heated stainless steel impingement surface modeling the inside turbine blade wall cooled by the impingement from the vane cooling insert, providing complementary data sets. The temperature data allow for the calculation of wall heat transfer (HT) characteristics, including the Nusselt number distribution for cooling performance analysis to inform design and validate computational models. Quantitative and qualitative comparisons of the paired results show that the flow velocity and cooling performance are highly coupled. Module-to-module variation in the surface Nusselt number distributions is evident, attributable to the complex interaction between transverse and impinging flows within the apparatus. Finally, a comparison with internal HT correlations is conducted using the data from Florschuetz et al. [1981, “Streamwiseflow and Heat Transfer Distributions for Jet Array Impingement With Crossflow,” ASME 1981 International Gas Turbine Conference and Products Show, American Society of Mechanical Engineers. doi:10.1115/1.3244463]. Measurement uncertainty was assessed and estimated to be approximately ±7% for velocity and ranging from ±3% to ±10% for Nusselt number