trans, trans-2,4-Decadienal, a lipid peroxidation product, induces inflammatory responses via Hsp90- or 14-3-3ζ-dependent mechanisms

Peroxidation of polyunsaturated fatty acids leads to the formation of a large array of lipid-derived electrophiles (LDEs), many of which are important signaling molecules involved in the pathogenesis of human diseases. Previous research has shown that one of such LDEs, trans, trans-2,4-decadienal (tt-DDE), increases inflammation, however, the underlying mechanisms are not well understood. Here we used click chemistry-based proteomics to identify the cellular targets which are required for the pro-inflammatory effects of tt-DDE. We found that treatment with tt-DDE increased cytokine production, JNK phosphorylation, and activation of NF-κB signaling in macrophage cells, and increased severity of dextran sulfate sodium (DSS)-induced colonic inflammation in mice, demonstrating its pro-inflammatory effects in vitro and in vivo. Using click chemistry-based proteomics, we found that tt-DDE directly interacts with Hsp90 and 14-3-3ζ, which are two important proteins involved in inflammation and tumorigenesis. Furthermore, siRNA knockdown of Hsp90 or 14-3-3ζ abolished the pro-inflammatory effects of tt-DDE in macrophage cells. Together, our results support that tt-DDE increases inflammatory responses via Hsp90- and 14-3-3ζ-dependent mechanisms.

How to evaluate effects of occupational therapy - lessons learned from an exploratory randomized controlled trial

BACKGROUND

Although occupational therapy (OT) is frequently prescribed in clinical practice, there is still insufficient evidence regarding its efficacy to improve Parkinson's Disease (PD)-related activity limitations.

OBJECTIVES

To evaluate the efficacy of OT and the validity of different outcome-parameters to reflect efficacy, including gold-standard clinical rating scales and quantitative motor assessments.

METHODS

40 patients were included in an exploratory, randomized-controlled, single-blinded trial, receiving either (I) ten weeks of OT, with a main focus on motor aspects of activity limitations and a ten-week follow-up assessment or (II) no intervention. Inclusion criteria were diagnosis of PD and Hoehn & Yahr stage 2-3. Patients with major depression, other neurological or orthopedic diseases or OT beforehand were excluded from the study. To monitor treatment effects the MDS-UPDRS part II and III were used for patient- and clinician-based assessment. Objective Pegboard as well as Q-Motor "tremormotography" and "digitomotography" were applied.

RESULTS

The interventional group reported a subjective amelioration of activity limitations, with a significant improvement of MDS-UPDRS part II at the end of the study (p = 0.030). However, clinician's rating and quantitative motor assessment failed to detect a significant improvement of motor impairment and fine motor control.

CONCLUSIONS

This study goes in line with previous trials, showing an individual improvement of activity limitations from the patients' point of view. The discrepancy between self-perception, focusing on activity limitation, and clinician-based rating, focusing on motor impairment, challenges the current gold standard assessments as valid outcome parameters for occupational therapy trials aiming for an individualized improvement of disease burden.

Accumulation of polyunsaturated aldehydes in the gonads of the copepod Acartia tonsa revealed by tailored fluorescent probes

Polyunsaturated aldehydes (PUAs) are released by several diatom species during predation. Besides other attributed activities, these oxylipins can interfere with the reproduction of copepods, important predators of diatoms. While intensive research has been carried out to document the effects of PUAs on copepod reproduction, little is known about the underlying mechanistic aspects of PUA action. Especially PUA uptake and accumulation in copepods has not been addressed to date. To investigate how PUAs are taken up and interfere with the reproduction in copepods we developed a fluorescent probe containing the α,β,γ,δ-unsaturated aldehyde structure element that is essential for the activity of PUAs as well as a set of control probes. We developed incubation and monitoring procedures for adult females of the calanoid copepod Acartia tonsa and show that the PUA derived fluorescent molecular probe selectively accumulates in the gonads of this copepod. In contrast, a saturated aldehyde derived probe of an inactive parent molecule was enriched in the lipid sac. This leads to a model for PUAs' teratogenic mode of action involving accumulation and covalent interaction with nucleophilic moieties in the copepod reproductive tissue. The teratogenic effect of PUAs can therefore be explained by a selective targeting of the molecules into the reproductive tissue of the herbivores, while more lipophilic but otherwise strongly related structures end up in lipid bodies.

A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

Molecular probes are widely used tools in chemical biology that allow tracing of bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I)-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive headgroup. Here we introduce the synthesis and application of the new thiazole-based, azide-tagged reporter 4-(3-azidopropoxy)-5-(4-bromophenyl)-2-(pyridin-2-yl)thiazole for fluorescence, UV and mass spectrometry (MS) detection. This small fluorescent reporter bears a bromine functionalization facilitating the automated data mining of electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC–MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously compares with commercially available azide-modified fluorophores and a brominated one. The ease of synthesis, small size, stability, and the universal detection possibilities make it an ideal reporter for activity-based protein profiling and functional metabolic profiling.

Matrix-free single-cell LDI-MS investigations of the diatoms Coscinodiscus granii and Thalassiosira pseudonana

Single-cell investigations of the diatoms Coscinodsicus granii and Thalassiosira pseudonana were performed using laser desorption/ionization (LDI)-MS without the addition of chemical matrices. The unique cell wall architecture of these microalgae, more precisely the biomineralized nanostructured surface, supported the ionization of cellular as well as surface-related metabolites. In model experiments with purified diatom cell walls of eight species C. granii and T. pseudonana proved to promote the ionization of the polymer polyethylene glycol most efficiently. These species were therefore chosen for further experiments. Without any additional workup, living diatom cells can be washed, can be placed on the LDI target and can immediately be profiled using LDI-MS. Characteristic signals arising from the two species were assigned to common metabolites known from diatom metabolism. Among others, chlorophyll, phospholipids and amino acids were detected. Using these fingerprint signals, we were able to perform species-specific MS imaging down to a single-cell resolution of 20 by 20 µm. The larger C. granii cells can be directly visualized, while more than one of the smaller T. pseudonana cells is needed to generate high-quality images. The introduced technique will pave the way toward a chemotyping of phytoplankton that will enable the automated annotation of microalgal species. But also, an assignment of metabolic plasticity on a single-cell level that could answer fundamental questions about plankton diversity is now in reach.

Utilization of thermal infrared image for inversion of winter wheat yield and biomass

The present paper utilizes thermal infrared image for inversion of winter wheat yield and biomass with different technology of irrigation (drip irrigation, sprinkler irrigation, flood irrigation). It is the first time that thermal infrared image is used for predicting the winter wheat yield and biomass. The temperature of crop and background was measured by thermal infrared image. It is necessary to get the crop background separation index (CBSI(L), CBSI(H)), which can be used for distinguishing the crop value from the image. CBSI(L) and CBSI(H) (the temperature when the leaves are wet adequately; the temperature when the stomata of leaf is closed completely) are the threshold values. The temperature of crop ranged from CBSI(L) to CBSI(H). Then the ICWSI was calculated based on relevant theoretical method. The value of stomata leaf has strong negative correlation with ICWSI proving the reliable value of ICWSI. In order to construct the high accuracy simulation model, the samples were divided into two parts. One was used for constructing the simulation model, the other for checking the accuracy of the model. Such result of the model was concluded as: (1) As for the simulation model of soil moisture, the correlation coefficient (R2) is larger than 0.887 6, the average of relative error (Er) ranges from 13.33% to 16.88%; (2) As for the simulation model of winter wheat yield, drip irrigation (0.887 6, 16.89%, -0.12), sprinkler irrigation (0.970 0, 14.85%, - 0.12), flood irrigation (0.969 0, 18.87%, -0.18), with the values of R2, Er and CRM listed in the parentheses followed by the individual term. (3) As for winter wheat biomass, drip irrigation (0.980 0, 13.70%, -0.13), sprinkler irrigation (0.95, 13.15%, -0.14), flood irrigation (0.970 0, 14.48%, -0.13), and the values in the parentheses are demonstrated the same as above. Both the CRM and Er are shown to be very low values, which points to the accuracy and reliability of the model investigated. The accuracy of model is high and reliable. The results indicated that thermal infrared image can be used potentially for inversion of winter wheat yield and biomass.

Epigallocatechin gallate attenuates diet-induced obesity in mice by decreasing energy absorption and increasing fat oxidation

OBJECTIVE

To examine the antiobesity effect of epigallocatechin gallate (EGCG), a green tea bioactive polyphenol in a mouse model of diet-induced obesity.

METHODS

Obesity was induced in male New Zealand black mice by feeding of a high-fat diet. EGCG purified from green tea (TEAVIGO) was supplemented in the diet (0.5 and 1%). Body composition (quantitative magnetic resonance), food intake, and food digestibility were recorded over a 4-week period. Animals were killed and mRNA levels of uncoupling proteins (UCP1-3), leptin, malic enzyme (ME), stearoyl-CoA desaturase-1 (SCD1), glucokinase (GK), and pyruvate kinase (PK) were analysed in different tissues. Also investigated were acute effects of orally administered EGCG (500 mg/kg) on body temperature, activity (transponders), and energy expenditure (indirect calorimetry).

RESULTS

Dietary supplementation of EGCG resulted in a dose-dependent attenuation of body fat accumulation. Food intake was not affected but faeces energy content was slightly increased by EGCG, indicating a reduced food digestibility and thus reduced long-term energy absorption. Leptin and SCD1 gene expression in white fat was reduced but SCD1 and UCP1 expression in brown fat was not changed. In liver, gene expression of SCD1, ME, and GK was reduced and that of UCP2 increased. Acute oral administration of EGCG over 3 days had no effect on body temperature, activity, and energy expenditure, whereas respiratory quotient during night (activity phase) was decreased, supportive of a decreased lipogenesis and increased fat oxidation.

CONCLUSIONS

Dietary EGCG attenuated diet-induced body fat accretion in mice. EGCG apparently promoted fat oxidation, but its fat-reducing effect could be entirely explained by its effect in reducing diet digestibility.

The impact of different flavonoid classes on colonic CI- secretion in rats

The plant polyphenol quercetin was shown to induce a significant CI- secretion in intestinal epithelium. In order to elucidate the structural requirements of quercetin and related flavonoids for this activity, we tested the ability of further flavonols and other flavonoids found in edible plants to induce CI- secretion which was measured as an increase in short-circuit current (I(SC)) in rat colon. Whereas several flavonols and the flavon luteolin increased I(SC), other flavonoids such as flavanones, flavans, flavanols, and anthocyanidins failed to do so. Two glycosides of quercetin, spiraeosid, and isoquercitrin, as well as two methoxylated quercetin metabolites, isorhamnetin and tamarixetin, were also able to increase I(SC). We conclude that a 2,3-double bond in conjunction with the 4-oxo group in the C ring and a hydroxylated B ring are necessary for the secretory activity of flavonoids. This activity requires different structural features than those mandatory for the antioxidative properties of flavonoids. Glucosidation and methoxylation of several hydroxyl groups does not necessarily abolish the secretory potential.

Transgenic myocardial overexpression of fibroblast growth factor-1 increases coronary artery density and branching

Fibroblast growth factor (FGF)-1 plays important roles during myocardial and coronary morphogenesis. FGF-1 is also involved in the physiological response of the adult heart against ischemia, which includes cardiomyocyte protection and vascular growth. In the present study, we have generated transgenic mice with specific myocardial overexpression of the gene. Transgene expression was verified by Northern blot, and increased FGF-1 protein content was assessed by Western blot and immunoconfocal microscopy. Anatomic, histomorphological, and ultrastructural analyses revealed no major morphological or developmental abnormalities of transgenic hearts. Capillary density was unaltered, whereas the density of coronary arteries, especially arterioles, was significantly increased, as was the number of branches of the main coronary arteries. In addition, the coronary flow was significantly enhanced in transgenic mice ex vivo. These differences in the anatomic pattern of the coronary vasculature are established during the second month of postnatal life. The present findings demonstrate an important role of FGF-1 in the differentiation and growth of the coronary system and suggest that it is a key regulatory molecule of the differentiation of the arterial system.

Selective interactions among the multiple connexin proteins expressed in the vertebrate lens: the second extracellular domain is a determinant of compatibility between connexins

Gap junctions are collections of intercellular channels composed of structural proteins called connexins (Cx). We have examined the functional interactions of the three rodent connexins present in the lens, Cx43, Cx46, and Cx50, by expressing them in paired Xenopus oocytes. Homotypic channels containing Cx43, Cx46, or Cx50 all developed high conductance. heterotypic channels composed of Cx46 paired with either Cx43 or Cx50 were also well coupled, whereas Cx50 did not form functional channels with Cx43. We also examined the functional response of homotypic and heterotypic channels to transjunctional voltage and cytoplasmic acidification. We show that all lens connexins exhibited sensitivity to cytoplasmic acidification as well as to voltage, and that voltage-dependent closure of heterotypic channels for a given connexin was dramatically influenced by its partner connexins in the adjacent cell. Based on the observation that Cx43 can discriminate between Cx46 and Cx50, we investigated the molecular determinants that specify compatibility by constructing chimeric connexins from portions of Cx46 and Cx50 and testing them for their ability to form channels with Cx43. When the second extracellular (E2) domain in Cx46 was replaced with the E2 of Cx50, the resulting chimera could no longer form heterotypic channels with Cx43. A reciprocal chimera, where the E2 of Cx46 was inserted into Cx50, acquired the ability to functionally interact with Cx43. Together, these results demonstrate that formation of intercellular channels is a selective process dependent on the identity of the connexins expressed in adjacent cells, and that the second extracellular domain is a determinant of heterotypic compatibility between connexins.

Na+-gradient dependence of basic amino acid transport into rat intestinal brush border membrane vesicles

Uptake of L-arginine and L-lysine into brush border membrane (BBM) vesicles from rats fed either a high protein (HP) or a high carbohydrate (HC) diet was studied under conditions of a transmembrane Na+-gradient (Na+out greater than Na+in) or a Na+-equilibrium (Na+out = Na+in). The Na+-gradient caused a stronger stimulation of basic amino acid transport across the BBM in group HP than in group HC. Replacing Cl- as counter ion of Na+ by SCN- in the Na+-gradient experiments did not affect L-lysine uptake. In one series of experiments inhibitory effects of several amino acids and D-glucose on Na+-gradient-dependent L-arginine transport into BBM vesicles were tested. L-Lysine showed the strongest inhibition of L-arginine uptake, but also L-leucine, L-alanine and D-glucose caused a significant decrease of L-arginine uptake into BBM vesicles. The main conclusions are that a transmembrane Na+-gradient is able to energize the transport of basic amino acids across the intestinal BBM and that the transport mechanism of the intestinal BBM for basic amino acids adapts to the protein content of the diet.