DGAT1 deficiency decreases PPAR expression and does not lead to lipotoxicity in cardiac and skeletal muscle

Diacylglycerol (DAG) acyl transferase 1 (Dgat1) knockout ((-/-)) mice are resistant to high-fat-induced obesity and insulin resistance, but the reasons are unclear. Dgat1(-/-) mice had reduced mRNA levels of all three Ppar genes and genes involved in fatty acid oxidation in the myocardium of Dgat1(-/-) mice. Although DGAT1 converts DAG to triglyceride (TG), tissue levels of DAG were not increased in Dgat1(-/-) mice. Hearts of chow-diet Dgat1(-/-) mice were larger than those of wild-type (WT) mice, but cardiac function was normal. Skeletal muscles from Dgat1(-/-) mice were also larger. Muscle hypertrophy factors phospho-AKT and phospho-mTOR were increased in Dgat1(-/-) cardiac and skeletal muscle. In contrast to muscle, liver from Dgat1(-/-) mice had no reduction in mRNA levels of genes mediating fatty acid oxidation. Glucose uptake was increased in cardiac and skeletal muscle in Dgat1(-/-) mice. Treatment with an inhibitor specific for DGAT1 led to similarly striking reductions in mRNA levels of genes mediating fatty acid oxidation in cardiac and skeletal muscle. These changes were reproduced in cultured myocytes with the DGAT1 inhibitor, which also blocked the increase in mRNA levels of Ppar genes and their targets induced by palmitic acid. Thus, loss of DGAT1 activity in muscles decreases mRNA levels of genes involved in lipid uptake and oxidation.     

Enhanced Responses to Tumor Immunization Following Total Body Irradiation Are Time-Dependent

The development of successful cancer vaccines is contingent on the ability to induce effective and persistent anti-tumor immunity against self-antigens that do not typically elicit immune responses. In this study, we examine the effects of a non-myeloablative dose of total body irradiation on the ability of tumor-naïve mice to respond to DNA vaccines against melanoma. We demonstrate that irradiation followed by lymphocyte infusion results in a dramatic increase in responsiveness to tumor vaccination, with augmentation of T cell responses to tumor antigens and tumor eradication. In irradiated mice, infused CD8⁺ T cells expand in an environment that is relatively depleted in regulatory T cells, and this correlates with improved CD8⁺ T cell functionality. We also observe an increase in the frequency of dendritic cells displaying an activated phenotype within lymphoid organs in the first 24 hours after irradiation. Intriguingly, both the relative decrease in regulatory T cells and increase in activated dendritic cells correspond with a brief window of augmented responsiveness to immunization. After this 24 hour window, the numbers of dendritic cells decline, as does the ability of mice to respond to immunizations. When immunizations are initiated within the period of augmented dendritic cell activation, mice develop anti-tumor responses that show increased durability as well as magnitude, and this approach leads to improved survival in experiments with mice bearing established tumors as well as in a spontaneous melanoma model. We conclude that irradiation can produce potent immune adjuvant effects independent of its ability to induce tumor ablation, and that the timing of immunization and lymphocyte infusion in the irradiated host are crucial for generating optimal anti-tumor immunity. Clinical strategies using these approaches must therefore optimize such parameters, as the correct timing of infusion and vaccination may mean the difference between an ineffective treatment and successful tumor eradication.     

Site-Specific Trade-offs of Harvesting Cereal Residues as Biofuel Feedstocks in Dryland Annual Cropping Systems of the Pacific Northwest,USA

Cereal residues are considered an important feedstock for future biofuel production. Harvesting residues, however, could lead to serious soil degradation and impaired agroecosystem services. Our objective was to evaluate trade-offs of harvesting wheat and barley residues including impacts on soil erosion and quality, soil organic C (SOC), and nutrient removal. We used agricultural data from 369 geo-referenced points on the 37-ha Washington State University Cook Agronomy Farm combined with model simulations to develop straw harvest scenarios for conventional tillage (CT) and no-tillage (NT) and both 2- and 3-year crop rotations with sequences of wheat, barley, and peas. Site-specific estimates of ethanol production from 2- and 3-year rotation scenarios ranged from 681 to 1,541 L ha^?1 yr^?1, indicating that both crop rotation and site-specific targeting of residue harvest are important factors. Harvesting straw reduced residue C inputs by 46 % and resulted in levels below that required to maintain SOC under CT. This occurred as a function of both straw harvest and low residue producing crops in rotation. Harvesting straw under CT was predicted to reduce soil quality as Soil Conditioning Indices (SCIs) were negative throughout the field. In contrast, SCIs under NT were positive despite straw harvest. Replacement value of nutrients (N, P, K, S) removed in harvested straw averaged $14.54 Mg^?1 dry straw and ranged from $36.04 to $80.30 ha^?1, while straw harvesting costs averaged $34.25 Mg^?1, and the current (2014) market value of straw is $65 Mg^?1. We concluded that substantial trade-offs exist in harvesting straw for biofuel, that trade-offs should be evaluated on a site-specific basis, and that support practices such as crop rotation, reduced tillage, and site-specific nutrient management need to be considered if residue harvest is to be sustainable.     

Optimal experimental design for sampling voltage on dendritic trees in the low-SNR regime

Due to the limitations of current voltage sensing techniques, optimal filtering of noisy, undersampled voltage signals on dendritic trees is a key problem in computational cellular neuroscience. These limitations lead to voltage data that is incomplete (in the sense of only capturing a small portion of the full spatiotemporal signal) and often highly noisy. In this paper we use a Kalman filtering framework to develop optimal experimental design methods for voltage sampling. Our approach is to use a simple greedy algorithm with lazy evaluation to minimize the expected square error of the estimated spatiotemporal voltage signal. We take advantage of some particular features of the dendritic filtering problem to efficiently calculate the Kalman estimator’s covariance. We test our framework with simulations of real dendritic branching structures and compare the quality of both time-invariant and time-varying sampling schemes. While the benefit of using the experimental design methods was modest in the time-invariant case, improvements of 25–100% over more na?ve methods were found when the observation locations were allowed to change with time. We also present a heuristic approximation to the greedy algorithm that is an order of magnitude faster while still providing comparable results.     

Resident phenotypically modulated vascular smooth muscle cells in healthy human arteries

Vascular interstitial cells (VICs) are non‐contractile cells with filopodia previously described in healthy blood vessels of rodents and their function remains unknown. The objective of this study was to identify VICs in human arteries and to ascertain their role. VICs were identified in the wall of human gastro‐omental arteries using transmission electron microscopy. Isolated VICs showed ability to form new and elongate existing filopodia and actively change body shape. Most importantly sprouting VICs were also observed in cell dispersal. RT‐PCR performed on separately collected contractile vascular smooth muscle cells (VSMCs) and VICs showed that both cell types expressed the gene for smooth muscle myosin heavy chain (SM‐MHC). Immunofluorescent labelling showed that both VSMCs and VICs had similar fluorescence for SM‐MHC and αSM‐actin, VICs, however, had significantly lower fluorescence for smoothelin, myosin light chain kinase, h‐calponin and SM22α. It was also found that VICs do not have cytoskeleton as rigid as in contractile VSMCs. VICs express number of VSMC‐specific proteins and display features of phenotypically modulated VSMCs with increased migratory abilities. VICs, therefore represent resident phenotypically modulated VSMCs that are present in human arteries under normal physiological conditions.     

The effects of calcium, temperature and phospholamban phosphorylation on the dynamics of the calcium-stimulated ATPase of canine cardiac sarcoplasmic reticulum

Highly purified sarcoplasmic reticulum (SR) has been prepared from dog hearts and has been incubated with the triplet probe erythrosinyl isothiocyanate to specifically label the Ca2+-stimulated ATPase (Ca2+-ATPase) of the SR. The rotational mobility of the Ca2+-ATPase has been studied in this erythrosin-labelled SR using time-resolved phosphorescence polarization. Qualitatively, the mobility of the cardiac Ca2+-ATPase resembles that of skeletal muscle SR Ca2+-ATPase. Addition of Ca2+ to SR affects the mobility of the Ca2+-ATPase in a way consistent with a segment of the ATPase altering its orientation relative to the plane of the membrane. Phosphorylation of phospholamban in cardiac SR by the purified catalytic subunit of cAMP-dependent protein kinase, which is known to increase the activity of the Ca2+-ATPase by deinhibition, also alters measured anisotropy. The changes observed are not compatible with dissociation of the Ca2+-ATPase from phospholamban after the latter is phosphorylated. The data are more consistent with phospholamban associating with the Ca2+-ATPase following phosphorylation, or more complex models in which only the hydrophilic domain of phospholamban binds with and dissociates from the Ca2+-ATPase.     

Frequency component selection for an ECoG-based brain-computer interface.

The aim of the present study was to investigate the most significant frequency components in electrocorticogram (ECoG) recordings in order to operate a brain computer interface (BCI). For this purpose the time-frequency ERD/ERS map and the distinction sensitive learning vector quantization (DSLVQ) are applied to ECoG from three subjects, recorded during a self-paced finger movement. The results show that the ERD/ERS pattern found in ECoG generally matches the ERD/ERS pattern found in EEG recordings, but has an increased prevalence of frequency components in the beta range.