Role of protein kinase C and NF-κB in proteolysis-inducing factor-induced proteasome expression in C2C12 myotubes

Proteolysis-inducing factor (PIF) is a sulphated glycoprotein produced by cachexia-inducing tumours, which initiates muscle protein degradation through an increased expression of the ubiquitin–proteasome proteolytic pathway. The role of kinase C (PKC) in PIF-induced proteasome expression has been studied in murine myotubes as a surrogate model of skeletal muscle. Proteasome expression induced by PIF was attenuated by 4alpha-phorbol 12-myristate 13-acetate (100 nM) and by the PKC inhibitors Ro31-8220 (10 muM), staurosporine (300 nM), calphostin C (300 nM) and Gö 6976 (200 muM). Proteolysis-inducing factor-induced activation of PKCalpha, with translocation from the cytosol to the membrane at the same concentration as that inducing proteasome expression, and this effect was attenuated by calphostin C. Myotubes transfected with a constitutively active PKCalpha (pCO2) showed increased expression of proteasome activity, and a longer time course, compared with their wild-type counterparts. In contrast, myotubes transfected with a dominant-negative PKCalpha (pKS1), which showed no activation of PKCalpha in response to PIF, exhibited no increase in proteasome activity at any time point. Proteolysis-inducing factor-induced proteasome expression has been suggested to involve the transcription factor nuclear factor-kappaB (NF-kappaB), which may be activated through PKC. Proteolysis-inducing factor induced a decrease in cytosolic I-kappaBalpha and an increase in nuclear binding of NF-kappaB in pCO2, but not in pKS1, and the effect in wild-type cells was attenuated by calphostin C, confirming that it was mediated through PKC. This suggests that PKC may be involved in the phosphorylation and degradation of I-kappaBalpha, induced by PIF, necessary for the release of NF-kappaB from its inactive cytosolic complex

Towards a resolution of some outstanding issues in transitive research: an empirical test on middle childhood

Transitive Inference (deduce B > D from B > C and C > D) can help us to understand other areas of sociocognitive development. Across three experiments, learning, memory, and the validity of two transitive paradigms were investigated. In Experiment 1 (N = 121), 7-year-olds completed a three-term nontraining task or a five-term task requiring extensive-training. Performance was superior on the three-term task. Experiment 2 presented 5–10-year-olds with a new five-term task, increasing learning opportunities without lengthening training (N = 71). Inferences improved, suggesting children can learn five-term series rapidly. Regarding memory, the minor (CD) premise was the best predictor of BD-inferential performance in both task-types. However, tasks exhibited different profiles according to associations between the major (BC) premise and BD inference, correlations between the premises, and the role of age. Experiment 3 (N = 227) helped rule out the possible objection that the above findings simply stemmed from three-term tasks with real objects being easier to solve than computer-tasks. It also confirmed that, unlike for five-term task (Experiments 1 & 2), inferences on three-term tasks improve with age, whether the age range is wide (Experiment 3) or narrow (Experiment 2). I conclude that the tasks indexed different routes within a dual-process conception of transitive reasoning: The five-term tasks indexes Type 1 (associative) processing, and the three-term task indexes Type 2 (analytic) processing. As well as demonstrating that both tasks are perfectly valid, these findings open up opportunities to use transitive tasks for educability, to investigate the role of transitivity in other domains of reasoning, and potentially to benefit the lived experiences of persons with developmental issues

Development of the SIOPE DIPG network, registry and imaging repository : a collaborative effort to optimize research into a rare and lethal disease

Diffuse intrinsic pontine glioma (DIPG) is a rare and deadly childhood malignancy. After 40 years of mostly single-center, often non-randomized trials with variable patient inclusions, there has been no improvement in survival. It is therefore time for international collaboration in DIPG research, to provide new hope for children, parents and medical professionals fighting DIPG. In a first step towards collaboration, in 2011, a network of biologists and clinicians working in the field of DIPG was established within the European Society for Paediatric Oncology (SIOPE) Brain Tumour Group: the SIOPE DIPG Network. By bringing together biomedical professionals and parents as patient representatives, several collaborative DIPG-related projects have been realized. With help from experts in the fields of information technology, and legal advisors, an international, web-based comprehensive database was developed, The SIOPE DIPG Registry and Imaging Repository, to centrally collect data of DIPG patients. As for April 2016, clinical data as well as MR-scans of 694 patients have been entered into the SIOPE DIPG Registry/Imaging Repository. The median progression free survival is 6.0 months (95% Confidence Interval (CI) 5.6-6.4 months) and the median overall survival is 11.0 months (95% CI 10.5-11.5 months). At two and five years post-diagnosis, 10 and 2% of patients are alive, respectively. The establishment of the SIOPE DIPG Network and SIOPE DIPG Registry means a paradigm shift towards collaborative research into DIPG. This is seen as an essential first step towards understanding the disease, improving care and (ultimately) cure for children with DIPG.Peer reviewe

Inclusion of indigenous peoples in CONFINTEA VI and follow-up processes

This paper discusses key issues raised by indigenous peoples during CONFINTEA VI and proposes strategies to enable them to participate in ongoing processes. Indigenous peoples are not involved in the design, implementation and monitoring of adult education programmes, and this often results in a “one-size-fits-all” model. This article takes the position that indigenous people must have full and effective participation in all matters which concern them and that well-meaning policy statements are only as effective as the display of real effort to make them work. One example of an indigenous community taking initiative in order to free itself of overwhelming deficit positioning by mainstream educational and other systems is the Māori community of Aotearoa/New Zealand. The paper argues that through CONFINTEA VI, there is still space for the voice of indigenous peoples to be heard

Signalling components underlying platelet aggregation to a Ca2+ ionophore and a phorbol ester.

Although it is well established that G(q)- and G(i)-coupled receptors can combine to mediate platelet aggregation, the signalling events underlying the synergy are not fully characterised. This study has used the calcium ionophore, A23187, and phorbol ester, PMA, to investigate this question. We show that aggregation to submaximal but not maximal concentrations of ionophore is partially inhibited by antagonism of the P2Y(12) ADP receptor or PKC blockade. However, a full aggregation response can be restored under these conditions by addition of PMA or ADP. Studies using PI 3-kinase inhibitors demonstrate that this is the second messenger pathway that restores aggregation by the G(i)-coupled receptor in the presence of PKC blockade. However, under normal circumstances, PI 3-kinase activity is not a major requirement for aggregation to the ionophore. PMA stimulates a weak aggregation which takes several minutes to reach a maximum. Threshold concentrations of PMA and a G(i)-coupled receptor agonist when added alone show no effect on aggregation, but when combined induce aggregation responses. This study demonstrates that calcium and PKC interact synergistically with a G(i)-coupled receptor agonist to mediate aggregation, and also with each other. Activation of G(i) supports aggregation in part through the PI 3-kinase pathway. High concentration of ionophore on their own can induce aggregation independent of PKC and activation of G(i). Multiple signalling pathways mediate platelet aggregation and their relative importance depends on experimental conditions

Signalling events underlying platelet aggregation induced by the glycoprotein VI agonist convulxin.

We have investigated the role of secretion and intracellular signalling events in aggregation induced by the glycoprotein (GP)VI-selective snake venom toxin convulxin and by collagen. We demonstrate that aggregation induced by threshold concentrations of convulxin undergoes synergy with ADP acting via the P2Y12 receptor whereas there is no synergy via the P2Y1 receptor or with thromboxanes. On the other hand, apyrase, the P2Y12 receptor antagonist, AR-C67085, and indomethacin only marginally inhibit aggregation induced by convulxin. In comparison, these inhibitors severely attenuate the response to collagen. In order to investigate whether the weak inhibitory action against convulxin is due to release of agonists other than ADP from dense granules, experiments were performed on murine platelets deficient in this organelle (pearl mice platelets). A slightly greater reduction in aggregation induced by convulxin was observed in pearl platelets than in the presence of inhibitors of ADP, but a maximal response was still attained. Importantly, inhibition of protein kinase C further reduced the response to convulxin in pearl platelets demonstrating a direct role for the kinase in aggregation. Chelation of intracellular Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N,N',N'-tetraacetic acid (acetoxymethyl)ester (BAPTA-AM) abolished aggregation induced by convulxin under all conditions. Activation of phospholipase C by convulxin was potentiated by ADP acting through the P2Y12 receptor. In conclusion, we show that Ca2+ and protein kinase C, but not release of the secondary agonists ADP and thromboxane A2, are required for full aggregation induced by convulxin, whereas the response induced by collagen shows a much greater dependence on secretion of secondary agonists

Signalling events underlying platelet aggregation induced by the glycoprotein VI agonist convulxin.

We have investigated the role of secretion and intracellular signalling events in aggregation induced by the glycoprotein (GP)VI-selective snake venom toxin convulxin and by collagen. We demonstrate that aggregation induced by threshold concentrations of convulxin undergoes synergy with ADP acting via the P2Y12 receptor whereas there is no synergy via the P2Y1 receptor or with thromboxanes. On the other hand, apyrase, the P2Y12 receptor antagonist, AR-C67085, and indomethacin only marginally inhibit aggregation induced by convulxin. In comparison, these inhibitors severely attenuate the response to collagen. In order to investigate whether the weak inhibitory action against convulxin is due to release of agonists other than ADP from dense granules, experiments were performed on murine platelets deficient in this organelle (pearl mice platelets). A slightly greater reduction in aggregation induced by convulxin was observed in pearl platelets than in the presence of inhibitors of ADP, but a maximal response was still attained. Importantly, inhibition of protein kinase C further reduced the response to convulxin in pearl platelets demonstrating a direct role for the kinase in aggregation. Chelation of intracellular Ca2+ with 1,2-bis(2-aminophenoxy)ethane-N,N,N,N',N'-tetraacetic acid (acetoxymethyl)ester (BAPTA-AM) abolished aggregation induced by convulxin under all conditions. Activation of phospholipase C by convulxin was potentiated by ADP acting through the P2Y12 receptor. In conclusion, we show that Ca2+ and protein kinase C, but not release of the secondary agonists ADP and thromboxane A2, are required for full aggregation induced by convulxin, whereas the response induced by collagen shows a much greater dependence on secretion of secondary agonists.