Melanotrope Secretory Cycle is Regulated by Physiological Inputs via the Hypothalamus

Previously, it has been shown that background color conditions regulate the overall activity of the frog intermediate lobe by varying the proportions of the two subtypes of melanotropes existing in the gland, the highly active or secretory melanotropes and hormone-storage melanotropes, depending on melanocyte-stimulating hormone ( -MSH) requirements. However, the factors and mechanisms underlying these background-induced changes are still unknown. In the present study, we investigated whether hypothalamic factors known to regulate melanotrope cell function can induce changes in vitro similar to those caused by background adaptation in vivo. We found that the inhibitors apomorphine (a dopamine receptor agonist) and NPY decreased the number of active melanotropes and increased simultaneously that of storage melanotropes. On the other hand, the stimulator TRH increased the number of active cells and concomitantly reduced that of storage cells. Inasmuch as none of these treatments modified the apoptotic and proliferation rates in melanotrope cells, it appears that these hypothalamic factors caused actual interconversions of cells from a subpopulation to its counterpart. When taken together, these findings suggest that the hypothalamus would control melanotrope activity not only through short-term regulation of hormone synthesis and release, but also through a long-term regulation of the secretory phenotype of these cells whereby the activity of the intermediate lobe would be adjusted to fulfill the hormonal requirements imposed by background conditions

Down-Regulation of GABAA Receptor via Promiscuity with the Vasoactive Peptide Urotensin II Receptor. Potential Involvement in Astrocyte Plasticity

GABAA receptor (GABAAR) expression level is inversely correlated with the proliferation rate of astrocytes after stroke or during malignancy of astrocytoma, leading to the hypothesis that GABAAR expression/activation may work as a cell proliferation repressor. A number of vasoactive peptides exhibit the potential to modulate astrocyte proliferation, and the question whether these mechanisms may imply alteration in GABAAR-mediated functions and/or plasma membrane densities is open. The peptide urotensin II (UII) activates a G protein-coupled receptor named UT, and mediates potent vasoconstriction or vasodilation in mammalian vasculature. We have previously demonstrated that UII activates a PLC/PIPs/Ca2+ transduction pathway, via both Gq and Gi/o proteins and stimulates astrocyte proliferation in culture. It was also shown that UT/Gq/IP3 coupling is regulated by the GABAAR in rat cultured astrocytes. Here we report that UT and GABAAR are co-expressed in cerebellar glial cells from rat brain slices, in human native astrocytes and in glioma cell line, and that UII inhibited the GABAergic activity in rat cultured astrocytes. In CHO cell line co-expressing human UT and combinations of GABAAR subunits, UII markedly depressed the GABA current (β3γ2>α2β3γ2>α2β1γ2). This effect, characterized by a fast short-term inhibition followed by drastic and irreversible run-down, is not relayed by G proteins. The run-down partially involves Ca2+ and phosphorylation processes, requires dynamin, and results from GABAAR internalization. Thus, activation of the vasoactive G protein-coupled receptor UT triggers functional inhibition and endocytosis of GABAAR in CHO and human astrocytes, via its receptor C-terminus. This UII-induced disappearance of the repressor activity of GABAAR, may play a key role in the initiation of astrocyte proliferation

A whole-genome sequence and transcriptome perspective on HER2-positive breast cancers.

HER2-positive breast cancer has long proven to be a clinically distinct class of breast cancers for which several targeted therapies are now available. However, resistance to the treatment associated with specific gene expressions or mutations has been observed, revealing the underlying diversity of these cancers. Therefore, understanding the full extent of the HER2-positive disease heterogeneity still remains challenging. Here we carry out an in-depth genomic characterization of 64 HER2-positive breast tumour genomes that exhibit four subgroups, based on the expression data, with distinctive genomic features in terms of somatic mutations, copy-number changes or structural variations. The results suggest that, despite being clinically defined by a specific gene amplification, HER2-positive tumours melt into the whole luminal-basal breast cancer spectrum rather than standing apart. The results also lead to a refined ERBB2 amplicon of 106 kb and show that several cases of amplifications are compatible with a breakage-fusion-bridge mechanism

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

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An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at root s=13 TeV

Peer reviewe

Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe