Brain activity during a working memory task after daily caffeine intake and caffeine withdrawal: a randomized double-blind placebo-controlled trial

Acute caffeine intake has been found to increase working memory (WM)-related brain activity in healthy adults without improving behavioral performances. The impact of daily caffeine intake-a ritual shared by 80% of the population worldwide-and of its discontinuation on working memory and its neural correlates remained unknown. In this double-blind, randomized, crossover study, we examined working memory functions in 20 young healthy non-smokers (age: 26.4 ± 4.0 years; body mass index: 22.7 ± 1.4 kg/m$^{2}$; and habitual caffeine intake: 474.1 ± 107.5 mg/day) in a 10-day caffeine (150 mg × 3 times/day), a 10-day placebo (3 times/day), and a withdrawal condition (9-day caffeine followed by 1-day placebo). Throughout the 10th day of each condition, participants performed four times a working memory task (N-Back, comprising 3- and 0-back), and task-related blood-oxygen-level-dependent (BOLD) activity was measured in the last session with functional magnetic resonance imaging. Compared to placebo, participants showed a higher error rate and a longer reaction time in 3- against 0-back trials in the caffeine condition; also, in the withdrawal condition we observed a higher error rate compared to placebo. However, task-related BOLD activity, i.e., an increased attention network and decreased default mode network activity in 3- versus 0-back, did not show significant differences among three conditions. Interestingly, irrespective of 3- or 0-back, BOLD activity was reduced in the right hippocampus in the caffeine condition compared to placebo. Adding to the earlier evidence showing increasing cerebral metabolic demands for WM function after acute caffeine intake, our data suggest that such demands might be impeded over daily intake and therefore result in a worse performance. Finally, the reduced hippocampal activity may reflect caffeine-associated hippocampal grey matter plasticity reported in the previous analysis. The findings of this study reveal an adapted neurocognitive response to daily caffeine exposure and highlight the importance of classifying impacts of caffeine on clinical and healthy populations

Opa Proteins of Pathogenic Neisseriae Initiate Src Kinase-Dependent or Lipid Raft-Mediated Uptake via Distinct Human Carcinoembryonic Antigen-Related Cell Adhesion Molecule Isoforms▿ †

Several pathogenic bacteria exploit human carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) for adhesion to and invasion into their host cells. CEACAM isoforms have characteristic expression patterns on epithelial, endothelial, or hematopoietic cells, providing bacteria with distinct sets of receptors on particular tissues. For example, while CEACAM1 and CEACAM6 have a wide tissue distribution, CEACAM3, CEACAM4, and CEACAM8 are uniquely expressed on primary human granulocytes, whereas CEA and CEACAM7 are limited to epithelia. By reconstitution of a CEACAM-deficient cell line with individual CEACAMs, we have analyzed the requirements for CEACAM-mediated internalization of Neisseria gonorrhoeae. Our results point to two mechanistically different uptake pathways triggered by either epithelial CEACAMs (CEACAM1, CEA, and CEACAM6) or the granulocyte-specific CEACAM3. In particular, CEACAM3-mediated uptake critically depends on Src family protein tyrosine kinase (PTK) activity, and CEACAM3 associates with the SH2 domains of several Src PTKs. In contrast, epithelial CEACAMs require the integrity of cholesterol-rich membrane microdomains and are affected by cholesterol depletion, whereas CEACAM3-mediated uptake by transfected cells or the opsonin-independent phagocytosis by human granulocytes is not altered in the presence of cholesterol chelators. These results allow the subdivision of all human CEACAMs known to be utilized as pathogen receptors into functional groups and point to important consequences for bacterial engagement of distinct CEACAM isoforms

Epithelial cells as active player in fibrosis: findings from an in vitro model.

Kidney fibrosis, a scarring of the tubulo-interstitial space, is due to activation of interstitial myofibroblasts recruited locally or systemically with consecutive extracellular matrix deposition. Newly published clinical studies correlating acute kidney injury (AKI) to chronic kidney disease (CKD) challenge this pathological concept putting tubular epithelial cells into the spotlight. In this work we investigated the role of epithelial cells in fibrosis using a simple controlled in vitro system. An epithelial/mesenchymal 3D cell culture model composed of human proximal renal tubular cells and fibroblasts was challenged with toxic doses of Cisplatin, thus injuring epithelial cells. RT-PCR for classical fibrotic markers was performed on fibroblasts to assess their modulation toward an activated myofibroblast phenotype in presence or absence of that stimulus. Epithelial cell lesion triggered a phenotypical modulation of fibroblasts toward activated myofibroblasts as assessed by main fibrotic marker analysis. Uninjured 3D cell culture as well as fibroblasts alone treated with toxic stimulus in the absence of epithelial cells were used as control. Our results, with the caveats due to the limited, but highly controllable and reproducible in vitro approach, suggest that epithelial cells can control and regulate fibroblast phenotype. Therefore they emerge as relevant target cells for the development of new preventive anti-fibrotic therapeutic approaches

Brain activity during a working memory task after daily caffeine intake and caffeine withdrawal: a randomized double-blind placebo-controlled trial

Abstract Acute caffeine intake has been found to increase working memory (WM)-related brain activity in healthy adults without improving behavioral performances. The impact of daily caffeine intake—a ritual shared by 80% of the population worldwide—and of its discontinuation on working memory and its neural correlates remained unknown. In this double-blind, randomized, crossover study, we examined working memory functions in 20 young healthy non-smokers (age: 26.4 ± 4.0 years; body mass index: 22.7 ± 1.4 kg/m2; and habitual caffeine intake: 474.1 ± 107.5 mg/day) in a 10-day caffeine (150 mg × 3 times/day), a 10-day placebo (3 times/day), and a withdrawal condition (9-day caffeine followed by 1-day placebo). Throughout the 10th day of each condition, participants performed four times a working memory task (N-Back, comprising 3- and 0-back), and task-related blood-oxygen-level-dependent (BOLD) activity was measured in the last session with functional magnetic resonance imaging. Compared to placebo, participants showed a higher error rate and a longer reaction time in 3- against 0-back trials in the caffeine condition; also, in the withdrawal condition we observed a higher error rate compared to placebo. However, task-related BOLD activity, i.e., an increased attention network and decreased default mode network activity in 3- versus 0-back, did not show significant differences among three conditions. Interestingly, irrespective of 3- or 0-back, BOLD activity was reduced in the right hippocampus in the caffeine condition compared to placebo. Adding to the earlier evidence showing increasing cerebral metabolic demands for WM function after acute caffeine intake, our data suggest that such demands might be impeded over daily intake and therefore result in a worse performance. Finally, the reduced hippocampal activity may reflect caffeine-associated hippocampal grey matter plasticity reported in the previous analysis. The findings of this study reveal an adapted neurocognitive response to daily caffeine exposure and highlight the importance of classifying impacts of caffeine on clinical and healthy populations

Monitoring and manipulating cellular crosstalk during kidney fibrosis inside a 3D in vitro co-culture

In pharmacological research the development of promising lead compounds requires a detailed understanding of the dynamics of disease progression. However, for many diseases, such as kidney fibrosis, gaining such understanding requires complex real-time, multi-dimensional analysis of diseased and healthy tissue. To allow for such studies with increased throughput we established a dextran hydrogel-based in vitro 3D co-culture as a disease model for kidney fibrosis aimed at the discovery of compounds modulating the epithelial/mesenchymal crosstalk. This platform mimics a simplified pathological renal microenvironment at the interface between tubular epithelial cells and surrounding quiescent fibroblasts. We combined this 3D technology with epithelial reporter cell lines expressing fluorescent biomarkers in order to visualize pathophysiological cell state changes resulting from toxin-mediated chemical injury. Epithelial cell damage onset was robustly detected by image-based monitoring, and injured epithelial spheroids induced myofibroblast differentiation of co-cultured quiescent human fibroblasts. The presented 3D co-culture system therefore provides a unique model system for screening of novel therapeutic molecules capable to interfere and modulate the dialogue between epithelial and mesenchymal cells.ISSN:2045-232

Combining entomopathogenic Pseudomonas bacteria, nematodes and fungi for biological control of a below-ground insect pest

Below-ground insect pests are challenging to control because they are hard to target with control measures. Moreover, broad spectrum insecticides are or will soon be banned due to their negative effects on non-target organisms. In this study, we have developed a biological control method for the cabbage maggot Delia radicum (Diptera: Anthomyiidae), a significant pest of Brassicacean crops, based on a consortium of three biocontrol agents (BCAs). We chose the bacterium Pseudomonas chlororaphis because it can be used in a dual strategy against insect pests and fungal plant diseases, and combined it with the nematode Steinernema feltiae and the fungus Metarhizium brunneum that have a long history of commercial use against different pest insects. Our aim was to combine BCAs with different modes of action in order to achieve a stable and reliable biocontrol effect. We first tested double combinations of the bacterium with either the nematode or the fungus for improved potential to kill D. radicum in laboratory assays. We then evaluated the effect of double and triple combinations on D. radicum development and maggot-induced damage on radish bulbs in a series of pot experiments with artificial cabbage maggot infection performed in the greenhouse and outdoors and finally in a field trial with a natural infestation. Our results show that i) insecticidal pseudomonads are highly efficient in D. radicum control, ii) the three BCAs are compatible and neither inhibit each other's infectiousness nor survival in the soil or on the roots, iii) synergistic effects of Pseudomonas-nematode and Pseudomonas-fungus combinations on maggot killing are possible, and iv) the triple combination reduced both pest survival in greenhouse experiments and maggot-induced damage on radish bulbs in the field by 50% each. The strategy we present here is a promising step forward to a reliable and efficient environmentally friendly biological control method for the cabbage maggot, which can also be adapted to other problematic below-ground pests.ISSN:0167-8809ISSN:1873-230

Epithelial cell injury characterization (upper panel) and fibroblast activation (lower panel) in an <i>in vitro</i> reconstructed microenvironment.

<p>(<b>A</b>) Scheme of the reconstructed microenvironment and workflow analysis of the cisplatin-injured proximal tubular epithelial cells HKC-8 cells and of the WS-1 dermal fibroblasts. (<b>B</b>) Cell viability and (<b>C</b>) apoptosis analysis. Cisplatin-treated proximal tubular epithelial cells HKC-8 cells showed decreased cell viability and increased apoptosis. (<b>D</b>). Cell cycle analysis showed that HKC-8 cells treated with cisplatin high dose (40 µM) were blocked in G2/M phase at 24, 48 and 72 h, whereas cells treated with the low dose (20 µM) reverted at 72 h to a condition similar to control. Cytokine release analysis with (<b>E</b>) IL-6 and (<b>F</b>) RANTES levels. Cisplatin-treated HKC-8 cells produced increased amounts of IL-6 and RANTES. (<b>G</b>) Gene-level analysis results for selected genes showing a stronger response to Ciplatin high dose (CisHigh) than to Ciplatin low dose (CisLow). Expression levels on a logarithmic scale are shown as a heat map: no detectable expression is indicated by black color, increasing expression levels are indicated by brighter shades of yellow. Note that several genes show up twice in the figure because they are represented by multiple probes on the Illumina chip. While the measured values do not necessarily agree, the overall trend of up-regulation is the same. (<b>H</b>) Gene-level analysis was complemented by a network-level approach using Gene Set Enrichment Analysis against the Pathway Commons collection of gene regulatory networks (<a href="http://www.pathwaycommons.org" target="_blank">www.pathwaycommons.org</a>). Cisplatin treated cells (L: low, H: high) were compared to controls (C), and renal clear cell carcinoma (RCC) cells were compared to “normal adjacent” tissue (GEO accession number GSE781; as this data set is based on a different expression array technology, we did not compare expression levels of individual genes for this analysis). The heat map shows FDR-corrected q values on a logarithmic scale for up-regulated (red shades) and down-regulated networks (green shades), black indicating no change. An FDR-corrected q value of 0.01 corresponds to an absolute score of 4.6 on this scale. Please, note that the RCC dataset (last column) does not imply any involvement of the networks shown here. (<b>I–L</b>) RT-PCR analysis and mRNA levels of the (<b>I</b>) <i>Acta2</i> gene (encoding alpha smooth muscle actin) (<b>J</b>) <i>TGF-b1</i>gene (encoding transforming growth factor beta 1), (<b>K</b>) <i>COL1A1</i> gene (encoding collagen-1α1) and (<b>L</b>) ID-1 gene (encoding Inhibitor of differentiation 1). Retrieved WS-1 dermal fibroblasts showed increased level for key fibrotic markers α-SMA, TGF-β1 and Collagen 1α1 and decreased level of ID-1 when epithelial cells HK-C8 cells were layered on top. Gene expression profile for the same gene in absence of HK-C8 cells can be found in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0056575#pone.0056575.s002" target="_blank">Figure S2B</a>-E. n.s. = not statistically different, * = p<0.05, ** = p<0.001.</p

Stable incorporation of α-smooth muscle actin into stress fibers is dependent on specific tropomyosin isoforms

α-Smooth Muscle Actin (α-SMA), a widely characterized cytoskeletal protein, represents the hallmark of myofibroblast differentiation. Transforming growth factorβ1 (TGFβ1) stimulates α-SMA expression and incorporation into stress fibers, thus providing an increased myofibroblast contractile force that participates in tissue remodeling. We have addressed the molecular mechanism by which α-SMA is stably incorporated into stress fibers in human myofibroblasts following exposure to TGFβ1. The unique N-terminal sequence AcEEED, which is critical for α-SMA incorporation into stress fibers, was used to screen for AcEEED binding proteins. Tropomyosins were identified as candidate binding proteins. We find that after TGFβ1 treatment elevated levels of the Tpm1.6/7 isoforms, and to a lesser extent Tpm2.1, precede the increase in α-SMA. RNA interference experiments demonstrate that α-SMA fails to stably incorporate into stress fibers of TGFβ1 treated fibroblasts depleted of Tpm1.6/7, but not other tropomyosins. This does not appear to be due to exclusive interactions between α-SMA and just the Tpm1.6/7 isoforms. We propose that an additional AcEEED binding factor may be required to generate α-SMA filaments containing just Tpm1.6/7 which result in stable incorporation of the resulting filaments into stress fibers