MicroRNAs Regulate Metabolic Phenotypes During Multicellular Tumor Spheroids Progression

During tumor progression, cancer cells rewire their metabolism to face their bioenergetic demands. In recent years, microRNAs (miRNAs) have emerged as regulatory elements that inhibit the translation and stability of crucial mRNAs, some of them causing direct metabolic alterations in cancer. In this study, we investigated the relationship between miRNAs and their targets mRNAs that control metabolism, and how this fine-tuned regulation is diversified depending on the tumor stage. To do so, we implemented a paired analysis of RNA-seq and small RNA-seq in a breast cancer cell line (MCF7). The cell line was cultured in multicellular tumor spheroid (MCTS) and monoculture conditions. For MCTS, we selected two-time points during their development to recapitulate a proliferative and quiescent stage and contrast their miRNA and mRNA expression patterns associated with metabolism. As a result, we identified a set of new direct putative regulatory interactions between miRNAs and metabolic mRNAs representative for proliferative and quiescent stages. Notably, our study allows us to suggest that miR-3143 regulates the carbon metabolism by targeting hexokinase-2. Also, we found that the overexpression of several miRNAs could directly overturn the expression of mRNAs that control glycerophospholipid and N-Glycan metabolism. While this set of miRNAs downregulates their expression in the quiescent stage, the same set is upregulated in proliferative stages. This last finding suggests an additional metabolic switch of the above mentioned metabolic pathways between the quiescent and proliferative stages. Our results contribute to a better understanding of how miRNAs modulate the metabolic landscape in breast cancer MCTS, which eventually will help to design new strategies to mitigate cancer phenotype.

Identification of compounds active against quiescent artemisinin-resistant Plasmodium falciparum parasites via the quiescent-stage survival assay (QSA)

Background Quiescence is an unconventional mechanism of Plasmodium survival, mediating artemisinin resistance. This phenomenon increases the risk of clinical failures following artemisinin-based combination therapies (ACTs) by slowing parasite clearance and allowing the selection of parasites resistant to partner drugs. Objectives To thwart this multiresistance, the quiescent state of artemisinin-resistant parasites must be taken into consideration from the very early stages of the drug discovery process. Methods We designed a novel phenotypic assay we have named the quiescent-stage survival assay (QSA) to assess the antiplasmodial activity of drugs on quiescent parasites. This assay was first validated on quiescent forms from different artemisinin-resistant parasite lines (laboratory strain and field isolates), using two reference drugs with different mechanisms of action: chloroquine and atovaquone. Furthermore, the efficacies of different partner drugs of artemisinins used in ACTs were investigated against both laboratory strains and field isolates from Cambodia. Results Our results highlight that because of the mechanism of quiescence and the respective pharmacological targets of drugs, drug efficacies on artemisinin-resistant parasites may be different between quiescent parasites and their proliferating forms. Conclusions These data confirm the high relevance of adding the chemosensitivity evaluation of quiescent parasites by the specific in vitro QSA to the antiplasmodial drug development process in the current worrisome context of artemisinin resistance.

Hashimoto's Ophthalmopathy

Thyroid-associated ophthalmopathy is a self-limiting autoimmune disease associated mainly with Graves' disease, but also with Hashimoto's thyroiditis (HT) and euthyroid states. There are two distinct stages of the disease, an active inflammatory stage followed by inactive quiescent stage. Eye disease activity/severity is independent of gender, age, thyroid function, or smoking. There are no effective means of preventing the disease or reliably altering its course. Current therapeutic options include local supportive measures, corticosteroids, external beam radiation and steroid-sparing immunosuppressive agents for reducing the inflammation during active disease and surgery for correcting the residual abnormalities secondary to fibrosis in the inactive state of the disease. This chapter explores Hashimoto's ophthalmopathy.

Tracking of quiescence in Leishmania by quantifying the expression of GFP in the ribosomal DNA locus

Under stressful conditions some microorganisms adopt a quiescent stage characterized by a reversible non or slow proliferative condition that allows their survival. This adaptation was only recently discovered in Leishmania. We developed an in vitro model and a biosensor to track quiescence at population and single cell levels. The biosensor is a GFP reporter gene integrated within the 18S rDNA locus, which allows monitoring the expression of 18S rRNA (rGFP expression). We showed that rGFP expression decreased significantly and rapidly during the transition from extracellular promastigotes to intracellular amastigotes and that it was coupled in vitro with a decrease in replication as measured by BrdU incorporation. rGFP expression was useful to track the reversibility of quiescence in live cells and showed for the first time the heterogeneity of physiological stages among the population of amastigotes in which shallow and deep quiescent stages may coexist. We also validated the use of rGFP expression as a biosensor in animal models of latent infection. Our models and biosensor should allow further characterization of quiescence at metabolic and molecular level.

2D non-LTE modelling of a filament observed in the Hα line with the DST/IBIS spectropolarimeter

Context. We study a fragment of a large quiescent filament observed on May 29, 2017 by the Interferometric BIdimensional Spectropolarimeter (IBIS) mounted at the Dunn Solar Telescope. We focus on its quiescent stage prior to its eruption. Aims. We analyse the spectral observations obtained in the Hα line to derive the thermodynamic properties of the plasma of the observed fragment of the filament. Methods. We used a 2D filament model employing radiative transfer computations under conditions that depart from the local thermodynamic equilibrium. We employed a forward modelling technique in which we used the 2D model to produce synthetic Hα line profiles that we compared with the observations. We then found the set of model input parameters, which produces synthetic spectra with the best agreement with observations. Results. Our analysis shows that one part of the observed fragment of the filament is cooler, denser, and more dynamic than its other part that is hotter, less dense, and more quiescent. The derived temperatures in the first part range from 6000 K to 10 000 K and in the latter part from 11 000 K to 14 000 K. The gas pressure is 0.2–0.4 dyn cm−2 in the first part and around 0.15 dyn cm−2 in the latter part. The more dynamic nature of the first part is characterised by the line-of-sight velocities with absolute values of 6–7 km s−1 and microturbulent velocities of 8–9 km s−1. On the other hand, the latter part exhibits line-of-sight velocities with absolute values 0–2.5 km s−1 and microturbulent velocities of 4–6 km s−1.

Factors influencing decision making among ENT surgeons on performance of cortical mastoidectomy for CSOM-tubotympanic disease in quiescent/active stage: an opinion based study

<p class="abstract"><strong>Background:</strong> As the role of cortical mastoidectomy as an adjunct to tympanoplasty in the management of CSOM tubotympanic type - quiescent stage remains controversial even today; we intend to study the factors that influence the decision of ENT surgeons on whether or not to perform cortical mastoidectomy in patients with CSOM (chronic suppurative otitis media) - active or quiescent ear.</p><p class="abstract"><strong>Methods:</strong> During May to August 2016, 60 ENT surgeons within Chennai were asked to answer a pre-framed questionnaire on CSOM based on their personal surgical experience. The answers were collected by direct questionnaire method and the data subjected to appropriate statistical analysis.</p><p class="abstract"><strong>Results:</strong> 65% surgeons expected a minimum dry ear period of ≤30 days before considering tympanoplasty alone (group 1) and the rest 35% members expected more than 30 days of dry ear period (group 2). Surgeons ≤40 years of age expected lesser duration of dry ear period prior to consideration of tympanoplasty alone (p =0.016). Group 2 surgeons performed cortical mastoidectomy in more number of cases (&gt;50%) when compared to group 1 surgeons (p =0.03) for patients who presented first to them with a wet ear. There was a mixed opinion among surgeons within group 1 itself on whether or not they would do cortical mastoidectomy when they encountered patients who had congested remnant tympanic membrane, congested middle ear mucosa, myringosclerosis, ossicular chain discontinuity, sclerotic mastoids or treated septic foci in spite of the ear being dry for a month.</p><p><strong>Conclusions: </strong>Though many surgeons consider that 30 days of dry ear period is sufficient to consider tympanoplasty alone, there is a division of opinion among themselves while facing specific clinical scenarios.</p>