In vitro evidence for senescent multinucleated melanocytes as a source for tumor-initiating cells

Oncogenic signaling in melanocytes results in oncogene-induced senescence (OIS), a stable cell-cycle arrest frequently characterized by a bi- or multinuclear phenotype that is considered as a barrier to cancer progression. However, the long-sustained conviction that senescence is a truly irreversible process has recently been challenged. Still, it is not known whether cells driven into OIS can progress to cancer and thereby pose a potential threat. Here, we show that prolonged expression of the melanoma oncogene N-RAS61K in pigment cells overcomes OIS by triggering the emergence of tumor-initiating mononucleated stem-like cells from senescent cells. This progeny is dedifferentiated, highly proliferative, anoikis-resistant and induces fast growing, metastatic tumors. Our data describe that differentiated cells, which are driven into senescence by an oncogene, use this senescence state as trigger for tumor transformation, giving rise to highly aggressive tumor-initiating cells. These observations provide the first experimental in vitro evidence for the evasion of OIS on the cellular level and ensuing transformation

Pyruvate: immunonutritional effects on neutrophil intracellular amino or alpha-keto acid profiles and reactive oxygen species production

For the first time the immunonutritional role of pyruvate on neutrophils (PMN), free α-keto and amino acid profiles, important reactive oxygen species (ROS) produced [superoxide anion (O2−), hydrogen peroxide (H2O2)] as well as released myeloperoxidase (MPO) acitivity has been investigated. Exogenous pyruvate significantly increased PMN pyruvate, α-ketoglutarate, asparagine, glutamine, aspartate, glutamate, arginine, citrulline, alanine, glycine and serine in a dose as well as duration of exposure dependent manner. Moreover, increases in O2− formation, H2O2-generation and MPO acitivity in parallel with intracellular pyruvate changes have also been detected. Regarding the interesting findings presented here we believe, that pyruvate fulfils considerably the criteria for a potent immunonutritional molecule in the regulation of the PMN dynamic α-keto and amino acid pools. Moreover it also plays an important role in parallel modulation of the granulocyte-dependent innate immune regulation. Although further research is necessary to clarify pyruvate’s sole therapeutical role in critically ill patients’ immunonutrition, the first scientific successes seem to be very promising

Ocean acidification shows negligible impacts on high-latitude bacterial community structure in coastal pelagic mesocosms

The impact of ocean acidification and carbonation on microbial community structure was assessed during a large-scale in situ costal pelagic mesocosm study, included as part of the EPOCA 2010 Arctic campaign. The mesocosm experiment included ambient conditions (fjord) and nine mesocosms, with pCO2 range from ~145 to ~1420 μatm. Samples collected at nine time points (t-1, t1, t5, t7, t12, t14, t22, t26 to t28) in seven treatments (ambient fjord (~145), 2×~185, ~270, ~685, ~820, ~1050 μatm) were analysed for "free-living" and "particle associated" microbial community composition using 16S rRNA amplicon sequencing. This high-throughput sequencing analysis produced ~20 000 000 16S rRNA V4 reads, which comprised 7000 OTUs. The main variables structuring these communities were, sample origin (fjord or mesocosms) and the filter size fraction (free-living or particle associated). The community was significantly different between the fjord and both the control and elevated 2 mesocosms (which were not significant different) after nutrients were added to the mesocosms; suggesting that the addition of nutrients is the primary driver of the change in mesocosm community structure. The relative importance of each structuring variable depended greatly on the time at which the community was sampled in relation to the phytoplankton bloom. The size fraction was the second most important factor for community structure; separating free-living from particle-associated bacteria. When free-living and particle-associated bacteria were analysed separately at different time points, the only taxon pCO2 was found to significantly affect were the Gammaproteobacteria after nutrient addition. Finally, pCO2 treatment was found to be significantly correlated (non-linear) with 15 rare taxa, most of which increased in abundance with higher CO2

Blood Pressure During Endovascular Treatment Under Conscious Sedation or Local Anesthesia

OBJECTIVE: To evaluate the role of blood pressure (BP) as mediator of the effect of conscious sedation (CS) compared to local anesthesia (LA) on functional outcome after endovascular treatment (EVT). METHODS: Patients treated in the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands (MR CLEAN) Registry centers with CS or LA as preferred anesthetic approach during EVT for ischemic stroke were analyzed. First, we evaluated the effect of CS on area under the threshold (AUT), relative difference between baseline and lowest procedural mean arterial pressure (∆LMAP), and procedural BP trend, compared to LA. Second, we assessed the association between BP and functional outcome (modified Rankin Scale [mRS]) with multivariable regression. Lastly, we evaluated whether BP explained the effect of CS on mRS. RESULTS: In 440 patients with available BP data, patients treated under CS (n = 262) had larger AUTs (median 228 vs 23 mm Hg*min), larger ∆LMAP (median 16% vs 6%), and a more negative BP trend (-0.22 vs -0.08 mm Hg/min) compared to LA (n = 178). Larger ∆LMAP and AUTs were associated with worse mRS (adjusted common odds ratio [acOR] per 10% drop 0.87, 95% confidence interval [CI] 0.78-0.97, and acOR per 300 mm Hg*min 0.89, 95% CI 0.82-0.97). Patients treated under CS had worse mRS compared to LA (acOR 0.59, 95% CI 0.40-0.87) and this association remained when adjusting for ∆LMAP and AUT (acOR 0.62, 95% CI 0.42-0.92). CONCLUSIONS: Large BP drops are associated with worse functional outcome. However, BP drops do not explain the worse outcomes in the CS group

Morphine inhibits AP-1 activity and CD14 expression in leukocytes by a nitric oxide and opioid receptor-dependent mechanism

International audienceBackground: Activator protein 1 is a transcription factor involved in the regulation of proinflammatory mediators. Activation of phagocytes by lipopolysaccharide depends on the expression of CD14 on the cell surface. In this study, we investigated the effects of morphine and nitric oxide on CD14 expression and activator protein 1 activation in human blood monocytes and neutrophils as well as the leukocyte cell line HL-60.Methods: Whole blood was incubated with morphine, the nitric oxide donor S-nitroso-N-acetyl-penicillamine, naloxone or nitric oxide synthase inhibitors Nomega-nitro-l-arginine and Nomega-nitro-l-arginine-methylester and stimulated with lipopolysaccharide. Activator protein 1 nuclear content was determined by flow cytometry in human blood neutrophils and monocytes. CD14 expression on neutrophils was measured after incubation with fluorescein isothiocyanate-labelled antibodies. Electric mobility shift assay served for evaluation of activator protein 1 nuclear binding in HL-60 cells.Results: Incubation of whole blood with morphine and subsequent stimulation with lipopolysaccharide decreased activator protein 1 nuclear content. Exposure to naloxone before morphine treatment abolished morphine-induced inhibition of activator protein 1 activity in human blood monocytes and neutrophils. Nitric oxide synthase inhibitors also reversed morphine's effects. CD14 expression on neutrophils was reduced after morphine treatment. These effects were antagonized by nitric oxide synthase inhibitors and naloxone.Conclusion: Morphine inhibits activator protein 1 activation by a mu opioid receptor pathway coupled to nitric oxide as second messenger. The decrease in CD14 expression caused by morphine may play a role in inhibition of activator protein 1 activation following lipopolysaccharide treatment of phagocytes