Janus kinases 1 and 2 regulate chemokine-mediated integrin activation and naïve T-cell homing.

Janus kinases (JAKs) are central signaling molecules in cytokine receptor cascades. Although they have also been implicated in chemokine receptor signaling, this function continues to be debated. To address this issue, we established a nucleofection model in primary, nonactivated mouse T lymphocytes to silence JAK expression and to evaluate the ability of these cells to home to lymph nodes. Reduced JAK1 and JAK2 expression impaired naïve T-cell migration in response to gradients of the chemokines CXCL12 and CCL21. In vivo homing of JAK1/JAK2-deficient cells to lymph nodes decreased, whereas intranodal localization and motility were unaffected. JAK1 and JAK2 defects altered CXCL12- and CCL21-triggered ezrin/radixin/moesin (ERM) dephosphorylation and F-actin polymerization, as well as activation of lymphocyte function-associated Ag-1 and very late Ag-4 integrins. As a result, the cells did not adhere firmly to integrin substrates in response to these chemokines. The results demonstrate that JAK1/JAK2 participate in chemokine-induced integrin activation and might be considered a target for modulation of immune cell extravasation and therefore, control of inflammatory reactions.

Shying away: An observer-based microprocess analysis of experiential avoidance and resource activation in outpatients with generalized anxiety spectrum disorder

Despite long-standing calls for patient-focused research on individuals with generalized anxiety spectrum disorder there is little systematized knowledge about the in-session behaviors of these patients. The primary objective of this study was to describe of in-session trajectories of the patients' level of explication (as an indicator of an elaborated exposure of negative emotionality) and the patients' focus on their own resources and how these trajectories are associated with post-treatment outcome. In respect to GAD patients, a high level of explication might be seen as an indicator of successful exposure of avoided negative emotionality during therapy sessions. Observers made minute-by-minute ratings of 1100 minutes of video of 20 patients-therapists dyads. The results indicated that a higher level of explication generally observed at a later stage during the therapy sessions and the patients' focus on competencies at an early stage was highly associated with positive therapy outcome at assessment at post treatment, independent of pretreatment distress, rapid response of well-being and symptom reduction, as well as the therapists' professional experience and therapy lengths. These results will be discussed under the perspective of emotion regulation of patients and therapist's counterregulation. It is assumed that GAD-Patients are especially skilled in masking difficult emotions. Explication level and emotion regulation are important variables for this patient group but there's relation to outcome is different.

CX3CR1+ cells facilitate the activation of CD4 T cells in the colonic lamina propria during antigen-driven colitis

Dendritic cells (DCs) and macrophages populate the intestinal lamina propria to initiate immune responses required for the maintenance of intestinal homeostasis. To investigate whether CX3CR1(+) phagocytes communicate with CD4 T cells during the development of transfer colitis, we established an antigen-driven colitis model induced by the adoptive transfer of DsRed OT-II cells in CX3CR1(GFP/+) × RAG(-/-) recipients challenged with Escherichia coli expressing ovalbumin (OVA) fused to a cyan fluorescent protein (CFP). After colonization of CX3CR1(GFP/+) × RAG(-/-) animals with red fluorescent E. coli pCherry-OVA, colonic CX3CR1(+) cells but not CD103(+) DCs phagocytosed E. coli pCherry-OVA. Degraded bacterial-derived antigens are transported by CD103(+) DCs to mesenteric lymph nodes (MLNs), where CD103(+) DCs prime naive T cells. In RAG(-/-) recipients reconstituted with OT II cells and gavaged with OVA-expressing E. coli, colonic CX3CR1(+) phagocytes are in close contact with CD4 T cells and presented bacterial-derived antigens to CD4 T cells to activate and expand effector T cells.

The Early Activation Marker CD69 Regulates the Expression of Chemokines and CD4 T Cell Accumulation in Intestine

Migration of naïve and activated lymphocytes is regulated by the expression of various molecules such as chemokine receptors and ligands. CD69, the early activation marker of C-type lectin domain family, is also shown to regulate the lymphocyte migration by affecting their egress from the thymus and secondary lymphoid organs. Here, we aimed to investigate the role of CD69 in accumulation of CD4 T cells in intestine using murine models of inflammatory bowel disease. We found that genetic deletion of CD69 in mice increases the expression of the chemokines CCL-1, CXCL-10 and CCL-19 in CD4(+) T cells and/or CD4(-) cells. Efficient in vitro migration of CD69-deficient CD4 T cells toward the chemokine stimuli was the result of increased expression and/or affinity of chemokine receptors. In vivo CD69(-/-) CD4 T cells accumulate in the intestine in higher numbers than B6 CD4 T cells as observed in competitive homing assay, dextran sodium sulphate (DSS)-induced colitis and antigen-specific transfer colitis. In DSS colitis CD69(-/-) CD4 T cell accumulation in colonic lamina propria (cLP) was associated with increased expression of CCL-1, CXCL-10 and CCL-19 genes. Furthermore, treatment of DSS-administrated CD69(-/-) mice with the mixture of CCL-1, CXCL-10 and CCL-19 neutralizing Abs significantly decreased the histopathological signs of colitis. Transfer of OT-II×CD69(-/-) CD45RB(high) CD4 T cells into RAG(-/-) hosts induced CD4 T cell accumulation in cLP. This study showed CD69 as negative regulator of inflammatory responses in intestine as it decreases the expression of chemotactic receptors and ligands and reduces the accumulation of CD4 T cells in cLP during colitis.

The human vestibular cortex revealed by coordinate-based activation likelihood estimation meta-analysis.

The vestibular system contributes to the control of posture and eye movements and is also involved in various cognitive functions including spatial navigation and memory. These functions are subtended by projections to a vestibular cortex, whose exact location in the human brain is still a matter of debate (Lopez and Blanke, 2011). The vestibular cortex can be defined as the network of all cortical areas receiving inputs from the vestibular system, including areas where vestibular signals influence the processing of other sensory (e.g. somatosensory and visual) and motor signals. Previous neuroimaging studies used caloric vestibular stimulation (CVS), galvanic vestibular stimulation (GVS), and auditory stimulation (clicks and short-tone bursts) to activate the vestibular receptors and localize the vestibular cortex. However, these three methods differ regarding the receptors stimulated (otoliths, semicircular canals) and the concurrent activation of the tactile, thermal, nociceptive and auditory systems. To evaluate the convergence between these methods and provide a statistical analysis of the localization of the human vestibular cortex, we performed an activation likelihood estimation (ALE) meta-analysis of neuroimaging studies using CVS, GVS, and auditory stimuli. We analyzed a total of 352 activation foci reported in 16 studies carried out in a total of 192 healthy participants. The results reveal that the main regions activated by CVS, GVS, or auditory stimuli were located in the Sylvian fissure, insula, retroinsular cortex, fronto-parietal operculum, superior temporal gyrus, and cingulate cortex. Conjunction analysis indicated that regions showing convergence between two stimulation methods were located in the median (short gyrus III) and posterior (long gyrus IV) insula, parietal operculum and retroinsular cortex (Ri). The only area of convergence between all three methods of stimulation was located in Ri. The data indicate that Ri, parietal operculum and posterior insula are vestibular regions where afferents converge from otoliths and semicircular canals, and may thus be involved in the processing of signals informing about body rotations, translations and tilts. Results from the meta-analysis are in agreement with electrophysiological recordings in monkeys showing main vestibular projections in the transitional zone between Ri, the insular granular field (Ig), and SII.

CD40 activation induces NREM sleep and modulates genes associated with sleep homeostasis

The T-cell derived cytokine CD40 ligand is overexpressed in patients with autoimmune diseases. Through activation of its receptor, CD40 ligand leads to a tumor necrosis factor (TNF) receptor 1 (TNFR1) dependent impairment of locomotor activity in mice. Here we report that this effect is explained through a promotion of sleep, which was specific to non-rapid eye movement (NREM) sleep while REM sleep was suppressed. The increase in NREM sleep was accompanied by a decrease in EEG delta power during NREM sleep and by a decrease in the expression of transcripts in the cerebral cortex known to be associated with homeostatic sleep drive, such as Homer1a, Early growth response 2, Neuronal pentraxin 2, and Fos-like antigen 2. The effect of CD40 activation was mimicked by peripheral TNF injection and prevented by the TNF blocker etanercept. Our study indicates that sleep-wake dysregulation in autoimmune diseases may result from CD40 induced TNF:TNFR1 mediated alterations of molecular pathways, which regulate sleep-wake behavior.

XIAP Restricts TNF- and RIP3-Dependent Cell Death and Inflammasome Activation

X-linked inhibitor of apoptosis protein (XIAP) has been identified as a potent regulator of innate immune responses, and loss-of-function mutations in XIAP cause the development of the X-linked lymphoproliferative syndrome type 2 (XLP-2) in humans. Using gene-targeted mice, we show that loss of XIAP or deletion of its RING domain lead to excessive cell death and IL-1β secretion from dendritic cells triggered by diverse Toll-like receptor stimuli. Aberrant IL-1β secretion is TNF dependent and requires RIP3 but is independent of cIAP1/cIAP2. The observed cell death also requires TNF and RIP3 but proceeds independently of caspase-1/caspase-11 or caspase-8 function. Loss of XIAP results in aberrantly elevated ubiquitylation of RIP1 outside of TNFR complex I. Virally infected Xiap−/− mice present with symptoms reminiscent of XLP-2. Our data show that XIAP controls RIP3-dependent cell death and IL-1β secretion in response to TNF, which might contribute to hyperinflammation in patients with XLP-2.

Who is honest and why: Baseline activation in anterior insula predicts inter-individual differences in deceptive behavior

Humans engage in deceptive behavior that negatively affects others. The propensity to deceive is,however, characterized by vast inter-individual heterogeneity that is poorly understood. Attempts to investigate the origins of this heterogeneity have so far mainly relied on subjective measures and have shown little predictive power. Here, we used resting electroencephalography to measure objective and stable individual differences in neural baseline activation in combination with an ecologically valid deception paradigm. Results showed that task-independent baseline activation in the anterior insula, a brain area implicated in mapping internal bodily states and in representing emotional arousal and consciousfeelings, predicts individuals’ propensity for deceptive behavior. The higher the neural baseline activation in this area is, the lower individuals’ propensity to deceive. Moreover, results provide evidence that high baseline activation in the anterior insula is associated with negative affect and dispositional tendencies to avoid aversive emotional situations. These results provide converging neural and psychological evidence that individuals might avoid a deceptive act due to a highly active negative emotional system which would make a deceptive act too stressful and bothersome.

The diversity of activation markets in Europe

Purpose – The purpose of this article is to analyse the diversity of markets for the provision of activation services. Design/methodology/approach – The article is based on the outcomes of a project involving nine European countries. The project investigated changing forms of governance of income protection schemes and activation services for unemployed people. Diversity is investigated by focusing on five dimensions of diversity derived from the quasi‐market concept as developed by Le Grand: the purchasers, the providers, the customers, the purchaser‐provider split and the purchaser‐customer split. Findings – The paper finds considerable diversity in the design of markets for the provision of activation. Diversity is visible in all dimensions involved in the analysis. One interesting finding is that a full split between purchasers and providers hardly exists, although some countries have introduced a stricter split than others. Another finding concerns the voice and choice of service consumers, which seems hardly affected by the introduction of market mechanisms in the provision of activation. Finally, marketisation does not seem to be an irreversible project, as de‐marketisation processes were identified as well. Originality/value – Most current research into activation markets and their effects pays little attention to the issue of diversity in the design and functioning of markets. This article argues in favour of more systematic research of market diversity and of the variety of effects of various market models. Rather than comparing marketised with public service provision, a stronger focus on various market models may strengthen our insight into how service provision models affect the effectiveness of activation services.

Activation of intervertebral disc cells by co-culture with notochordal cells, conditioned medium and hypoxia

Notochordal cells (NC) remain in the focus of research for regenerative therapy for the degenerated intervertebral disc (IVD) due to their progenitor status. Recent findings suggested their regenerative action on more mature disc cells, presumably by the secretion of specific factors, which has been described as notochordal cell conditioned medium (NCCM). The aim of this study was to determine NC culture conditions (2D/3D, fetal calf serum, oxygen level) that lead to significant IVD cell activation in an indirect co-culture system under normoxia and hypoxia (2% oxygen).

Individual differences in inhibitory control - relationship between baseline activation in lateral PFC and an electrophysiological index of response inhibition

The capacity to inhibit inappropriate responses is crucial for goal-directed behavior. Inhibiting such responses seems to come more easily to some of us than others, however. From where do these individual differences originate? Here, we measured 263 participants' neural baseline activation using resting electroencephalogram. Then, we used this stable neural marker to predict a reliable electrophysiological index of response inhibition capacity in the cued Continuous Performance Test, the NoGo-Anteriorization (NGA). Using a source-localization technique, we found that resting delta, theta, and alpha1 activity in the left middle frontal gyrus and resting alpha1 activity in the right inferior frontal gyrus were negatively correlated with the NGA. As a larger NGA is thought to represent better response inhibition capacity, our findings demonstrate that lower levels of resting slow-wave oscillations in the lateral prefrontal cortex, bilaterally, are associated with a better response inhibition capacity.

Why Some People Discount More than Others: Baseline Activation in the Dorsal PFC Mediates the Link between COMT Genotype and Impatient Choice

Individuals differ widely in how steeply they discount future rewards. The sources of these stable individual differences in delay discounting (DD) are largely unknown. One candidate is the COMT Val158Met polymorphism, known to modulate prefrontal dopamine levels and affect DD. To identify possible neural mechanisms by which this polymorphism may contribute to stable individual DD differences, we measured 73 participants' neural baseline activation using resting electroencephalogram (EEG). Such neural baseline activation measures are highly heritable and stable over time, thus an ideal endophenotype candidate to explain how genes may influence behavior via individual differences in neural function. After EEG-recording, participants made a series of incentive-compatible intertemporal choices to determine the steepness of their DD. We found that COMT significantly affected DD and that this effect was mediated by baseline activation level in the left dorsal prefrontal cortex (DPFC): (i) COMT had a significant effect on DD such that the number of Val alleles was positively correlated with steeper DD (higher numbers of Val alleles means greater COMT activity and thus lower dopamine levels). (ii) A whole-brain search identified a cluster in left DPFC where baseline activation was correlated with DD; lower activation was associated with steeper DD. (iii) COMT had a significant effect on the baseline activation level in this left DPFC cluster such that a higher number of Val alleles was associated with lower baseline activation. (iv) The effect of COMT on DD was explained by the mediating effect of neural baseline activation in the left DPFC cluster. Our study thus establishes baseline activation level in left DPFC as salient neural signature in the form of an endophenotype that mediates the link between COMT and DD.

L-mimosine and dimethyloxaloylglycine decrease plasminogen activation in periodontal fibroblasts

BACKGROUND The use of prolyl hydroxylase inhibitors such as l-mimosine (L-MIM) and dimethyloxaloylglycine (DMOG) to improve angiogenesis is a new approach for periodontal regeneration. In addition to exhibiting pro-angiogenic effects, prolyl hydroxylase inhibitors can modulate the plasminogen activator system in cells from non-oral tissues. This study assesses the effect of prolyl hydroxylase inhibitors on plasminogen activation by fibroblasts from the periodontium. METHODS Gingival and periodontal ligament fibroblasts were incubated with L-MIM and DMOG. To investigate whether prolyl hydroxylase inhibitors modulate the net plasminogen activation, kinetic assays were performed with and without interleukin (IL)-1. Moreover, plasminogen activators and the respective inhibitors were analyzed by casein zymography, immune assays, and quantitative polymerase chain reaction. RESULTS The kinetic assay showed that L-MIM and DMOG reduced plasminogen activation under basal and IL-1-stimulated conditions. Casein zymography revealed that the effect of L-MIM involves a decrease in urokinase-type plasminogen activator activity. In agreement with these findings, reduced levels of urokinase-type plasminogen activator and elevated levels of plasminogen activator inhibitor 1 were observed. CONCLUSION L-MIM and DMOG can reduce plasminogen activation by fibroblasts from the gingiva and the periodontal ligament under basal conditions and in the presence of an inflammatory cytokine.

Atomic mutagenesis of the ribosomal Sarcin-Ricin-Loop to study EF-G GTPase activation

Translocation factor EF-G, possesses a low basal GTPase activity, which is stimulated by the ribosome. One potential region of the ribosome that triggers GTPase activity of EF-G is the Sarcin-Ricin-Loop (SRL) (helix 95) in domain VI of the 23S rRNA. Structural data showed that the tip of the SRL closely approaches GTP in the active center of EF-G, structural probing data confirmed that EF-G interacts with nucleotides G2655, A2660, G2661 and A2662.1-3 The exocyclic group of adenine at A2660 is required for stimulation of EF-G GTPase activity by the ribosome as demonstrated using atomic mutagenesis.4 Recent crystal structures of EF-G on the ribosome, gave more insights into the molecular mechanism of EF-G GTPase activity.5 Based on the structure of EF-Tu on the ribosome1, the following mechanism of GTPase activation was proposed: upon binding of EF-G to the ribosome, the conserved His92 (E.coli) changes its position, pointing to the γ-phosphate of GTP. In this activated state, the phosphate of residue A2662 of the SRL positions the catalytic His in its active conformation. It was further proposed that the phosphate oxygen of A2662 is involved in a charge-relay system, enabling GTP hydrolysis. In order to test this mechanism, we use the atomic mutagenesis approach, which allows introducing non-natural modifications in the SRL, in the context of the complete 70S ribosome. Therefore, we replaced one of the non-bridging oxygens of A2662 by a methyl group. A methylphosphonat is not able to position or activate a histidine, as it has no free electrons and therefore no proton acceptor function. These modified ribosomes were then tested for stimulation of EF-G GTPase activity. First experiments show that one of the two stereoisomers incorporated into ribosomes does not stimulate GTPase activity of EF-G, whereas the other is active. From this we conclude that indeed the non-bridging phosphate oxygen of A2662 is involved in EF-G GTPase activation by the ribosome. Ongoing experiments aim at revealing the contribution of this non-bridging oxygen at A2662 to the mechanism of EF-G GTPase activation at the atomic level.