Viral respiratory infections (VRIs) are a persistent global health concern, driven by the year-round circulation of diverse viruses. During the coronavirus disease 2019 (COVID-19) pandemic, the prevalence of most respiratory viruses declined sharply following nonpharmaceutical interventions. Their subsequent resurgence and co-circulation with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) created a novel and unpredictable VRI landscape. We investigated the respiratory virus dynamics and co-occurrence patterns in symptomatic outpatients in Switzerland, using nasopharyngeal specimens collected between August 2022 and July 2024 by the National Reference Center for Influenza. In total, 5,369 specimens were tested by PCR or RT-PCR for 16 respiratory viruses. Co-detections were identified in 9% of positive samples and occurred year-round. The majority involved two viruses (92%), although triple and quadruple detections were also observed. Statistical analysis showed that multiple detections were significantly more common in children. Their incidence was higher not only with the most prevalent ones, rhinoviruses (RVs) and SARS-CoV-2, but also with bocaviruses (hBoV) and adenoviruses (ADVs). A statistically significant decrease in viral load was observed when a second virus was co-detected with SARS-CoV-2 or respiratory syncytial virus (RSV), but not with influenza viruses. This effect was most pronounced in early- and middle-aged adults. Through the systematic investigation of viral co-occurrence, this study emphasizes the importance of community-based surveillance. Beyond monitoring respiratory disease burden, such surveillance provides a foundation for generating hypotheses to better understand viral interactions and the virus-host interplay during infection.IMPORTANCEViral respiratory infections (VRIs) are a major public health challenge due to their constant circulation and significant impact on vulnerable populations. The coronavirus disease 2019 (COVID-19) pandemic profoundly altered the dynamics of respiratory viruses, leading first to a sharp decline in their prevalence, followed by an unpredictable resurgence in co-circulation with Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). In this context, understanding viral interactions and their co-detection in the community has become essential. This project provides novel insights into the frequency and characteristics of viral co-infections in a real-world outpatient setting. It highlights age-related differences and demonstrates statistically significant effects on viral load, particularly for SARS-CoV-2 and respiratory syncytial virus (RSV). These findings underscore the importance of community-based surveillance, not only to monitor the overall burden of respiratory diseases but also to generate new hypotheses on virus-host interactions. Ultimately, this knowledge can guide the development of more effective prevention and management strategies.

Cells are exposed to a wide variety of internal and external stresses. Although many studies have focused on cellular responses to acute and severe stresses, little is known about how cellular systems adapt to sublethal chronic stresses. Using mammalian cells in culture, we discovered that they adapt to chronic mild stresses of up to two weeks, notably proteotoxic stresses such as heat, by increasing their size and translation, thereby scaling the amount of total protein. These adaptations render them more resilient to persistent and subsequent stresses. We demonstrate that Hsf1, well known for its role in acute stress responses, is required for the cell size increase, and that the molecular chaperone Hsp90 is essential for coupling the cell size increase to augmented translation. We term this translational reprogramming the ‘rewiring stress response’, and propose that this protective process of chronic stress adaptation contributes to the increase in size as cells get older, and that its failure promotes aging.

Cells are exposed to a wide variety of internal and external stresses.Whereas many studies have focused on cellular responses to acute and severe stresses, little is known about how cellular systems adapt to sublethal chronic stresses.Using mammalian cells in culture, we discovered that they adapt to chronic mild stresses, notably proteotoxic stresses such as heat, by increasing their size and translation, thereby scaling the amount of total protein.These adaptations render them more resilient to persistent and subsequent stresses.We demonstrate that Hsf1, well known for its role in acute stress responses, is required for the cell size increase, and that the molecular chaperone Hsp90 is essential for coupling the cell size increase to augmented translation.We term this translational reprogramming the "rewiring stress response", and propose that this protective process of chronic stress adaptation contributes to the increase in size as cells get older, and that its failure promotes aging. eLife assessmentThis is an important study that describes the coordinated regulation of cellular size and protein translation in response to chronic stress as an adaptive mechanism regulated by the heat shock response.The evidence supporting this conclusion is solid, utilizing diverse methods to monitor and manipulate cell size and evaluate stress resistance; however, it is currently unclear in the manuscript to what extent the effects observed are confounded by cell overcrowding.Additionally, the study could be strengthened by the inclusion of more experiments focused on defining the mechanistic basis of this coordination.This work will be of broad interest to researchers interested in diverse fields including cellular proteostasis, stressresponsive signaling, and aging and senescence.

Background Mucosal antibodies play a key role in the protection against SARS-CoV-2 infection in the upper respiratory tract, and potentially in limiting virus replication and therefore onward transmission. While systemic immunity to SARS-CoV-2 is well understood, we have a limited understanding about the antibodies present on the nasal mucosal surfaces.Methods In this study, we evaluated SARS-CoV-2 mucosal antibodies following previous infection, vaccination, or a combination of both. Paired nasal fluid and serum samples were collected from 143 individuals, which include convalescent, vaccinated, or breakthrough infections.Findings We detected a high correlation between IgG responses in serum and nasal fluids, which were higher in both compartments in vaccinated compared to convalescent participants. Contrary, nasal and systemic SARS-CoV-2 IgA responses were weakly correlated, indicating a compartmentalization between the local and systemic IgA responses. SARS-CoV-2 secretory component IgA (s-IgA) antibodies, present exclusively on mucosal surfaces, were detected in the nasal fluid only in a minority of vaccinated subjects and were significantly higher in previously infected individuals. Depletion of IgA antibodies in nasal fluids resulted in a tremendous reduction of neutralization activity against SARS-CoV-2, indicating that IgA is the crucial contributor to neutralization in the nasal mucosa. Neutralization against SARS-CoV-2 was higher in the mucosa of subjects with previous SARS-CoV2 infections compared to vaccinated participants.Interpretation In summary, we demonstrate that currently available vaccines elicit strong systemic antibody responses, but SARS-CoV-2 infection generates higher titers of binding and neutralizing mucosal antibodies. Our results support the importance to develop SARS-CoV-2 vaccines that elicit mucosal antibodies.Funding The work was funded by the COVID-19 National Research Program 78 (grant number 198412) of the Swiss National Science Foundation.Copyright (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Introduction Rhinovirus (RV) infections constitute one of the main triggers of asthma exacerbations and an important burden in pediatric yard. However, the mechanisms underlying this association remain poorly understood. Methods In the present study, we compared infections of in vitro reconstituted airway epithelia originating from asthmatic versus healthy donors with representative strains of RV-A major group and minor groups, RV-C, RV-B, and the respiratory enterovirus EV-D68. Results We found that viral replication was higher in tissues derived from asthmatic donors for all tested viruses. Viral receptor expression was comparable in non-infected tissues from both groups. After infection, ICAM1 and LDLR were upregulated, while CDHR3 was downregulated. Overall, these variations were related to viral replication levels. The presence of the CDHR3 asthma susceptibility allele (rs6967330) was not associated with increased RV-C replication. Regarding the tissue response, a significantly higher interferon (IFN) induction was demonstrated in infected tissues derived from asthmatic donors, which excludes a defect in IFN-response. Unbiased transcriptomic comparison of asthmatic versus control tissues revealed significant modifications, such as alterations of cilia structure and motility, in both infected and non-infected tissues. These observations were supported by a reduced mucociliary clearance and increased mucus secretion in non-infected tissues from asthmatic donors. Discussion Altogether, we demonstrated an increased permissiveness and susceptibility to RV and respiratory EV infections in HAE derived from asthmatic patients, which was associated with a global alteration in epithelial cell functions. These results unveil the mechanisms underlying the pathogenesis of asthma exacerbation and suggest interesting therapeutic targets.

SUMMARY There is a growing awareness that repeat sequences (RepSeq) - the main constituents of the human genome - are also prime players in its organization. Here we propose that the genome should be envisioned as a supersystem with three main subsystems, each composed of functionally redundant, cooperating elements. We define herein ProA and ProB RepSeqs as sequences that promote either the A/euchromatin or the B/heterochromatin compartment. ProA and ProB RepSeqs shape A/B partitioning, such that the relative proportions of ProA and ProB RepSeqs determine the propensity of a chromosome segment to adopt either an A or a B configuration. In human, core ProA RepSeqs are essentially made of Alu elements, whereas core ProB RepSeqs consist of young L1 and some Endogenous Retroviruses (ERVs) as well as a panel of AT-rich microsatellites and pericentromeric and telomeric satellites. Additionally, RepSeqs with more indefinite character and, importantly, their derivatives known as “transcriptional enhancers”, can shift between ProA and ProB functions and thus act to open or close specific chromatin domains depending on the cellular context. In this framework, genes and their promoters appear as a special class of RepSeqs that, in their active, transcribed state, reinforce the openness of their surroundings. Molecular mechanisms involve cooperativity between ProB elements, presumably underpinned by the condensate-like properties of heterochromatin, which ProA elements oppose in several ways. We provide strong arguments that altered CpG methylation patterns in cancer including a marked loss in the B compartment, result primarily from a global imbalance in the process of CpG methylation and its erasure. Our results suggest that the resulting altered methylation and impaired function of ProB RepSeqs globally weaken the B compartment, rendering it more plastic, which in turn may confer fate plasticity to the cancer cell.

Plasmalogens are an abundant class of glycerophospholipids in the mammalian body, with special occurrence in the brain and in immune cell membranes. Plasmanylethanolamine desaturase (PEDS1) is the final enzyme of plasmalogen biosynthesis, which introduces the characteristic 1-O-alk-1 '-enyl double bond. The recent sequence identification of PEDS1 as transmembrane protein 189 showed that its protein sequence is related to a special class of plant desaturases (FAD4), with whom it shares a motif of 8 conserved histidines, which are essential for the enzymatic activity. In the present work, we wanted to gain more insight into the sequence-function relationship of this enzyme and mutated to alanine additional 28 amino acid residues of murine plasmanylethanolamine desaturase including those 20 residues, which are also totally conserved-in addition to the eight-histidine-motif-among the animal PEDS1 and plant FAD4 plant desaturases. We measured the enzymatic activity by transient transfection of tagged murine PEDS1 expression clones to a PEDS1-deficient human HAP1 cell line by monitoring of labeled plasmalogens formed from supplemented 1-O-pyrenedecyl-sn-glycerol in relation to recombinant protein expression. Surprisingly, only a single mutation, namely aspartate 100, led to a total loss of PEDS1 activity. The second strongest impact on enzymatic activity had mutation of phenylalanine 118, leaving only 6% residual activity. A structural model obtained by homology modelling to available structures of stearoyl-CoA reductase predicted that this aspartate 100 residue interacts with histidine 96, and phenylalanine 118 interacts with histidine 187, both being essential histidines assumed to be involved in the coordination of the di-metal center of the enzyme.

Infectious viral load (VL) expelled as droplets and aerosols by infected individuals partly determines transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). RNA VL measured by qRT–PCR is only a weak proxy for infectiousness. Studies on the kinetics of infectious VL are important to understand the mechanisms behind the different transmissibility of SARS-CoV-2 variants and the effect of vaccination on transmission, which allows guidance of public health measures. In this study, we quantified infectious VL in individuals infected with SARS-CoV-2 during the first five symptomatic days by in vitro culturability assay in unvaccinated or vaccinated individuals infected with pre-variant of concern (pre-VOC) SARS-CoV-2, Delta or Omicron BA.1. Unvaccinated individuals infected with pre-VOC SARS-CoV-2 had lower infectious VL than Delta-infected unvaccinated individuals. Full vaccination (defined as >2 weeks after receipt of the second dose during the primary vaccination series) significantly reduced infectious VL for Delta breakthrough cases compared to unvaccinated individuals. For Omicron BA.1 breakthrough cases, reduced infectious VL was observed only in boosted but not in fully vaccinated individuals compared to unvaccinated individuals. In addition, infectious VL was lower in fully vaccinated Omicron BA.1-infected individuals compared to fully vaccinated Delta-infected individuals, suggesting that mechanisms other than increased infectious VL contribute to the high infectiousness of SARS-CoV-2 Omicron BA.1. Our findings indicate that vaccines may lower transmission risk and, therefore, have a public health benefit beyond the individual protection from severe disease. The infectious viral load of SARS-CoV-2 Omicron BA.1 is lower than that of Delta in symptomatic breakthrough infections of recipients of two doses of a COVID-19 vaccine, suggesting that the higher transmission of Omicron BA.1 is not linked to higher infectious viral load.

Background: We aim to analyse the existing health care-inequities particularly regarding preventable loss of sight, cognition, mobility, self-care, and communication between deaf and the non-deaf population in Colombia. Methods: This study presents a secondary cross-sectional analysis of the Colombian NQLS, 2019 . We included 289,558 participants in the analysis, stratified by whether they are deaf (n = 449) or non-deaf (n = 289,109). Odds ratios (ORs) were computed for various outcomes (difficulty/no difficulty, bad/good, yes/no, chronic illness/no chronic illness, consultation/no consultation, subsidised/contributory) for both deaf and non-deaf participants, using Fisher's exact test. Findings: The prevalence of deafness in Colombia was 0.16% (95% CIs 0.14% to 0.17%) of the general population, which is lower than the global prevalence. Overall, deaf people reported significantly high rates (ORs=4.8, 95% CIs 3.9 to 5.7, p-value<0.001) of chronic illness compared to non-deaf participants. Deaf people reported the quality of health service provision when they go for prevention to be two times significantly bad as compared to the non-deaf population. Deaf persons are significantly (all p-values<0.001) more likely to have additional activity limitations with regard to seeing (ORs=4.0, 95% CIs 3.3 to 4.8), walking (ORs=9.2, 95% CIs 7.6 to 11.2), cognitive functioning (ORs=33.8, 95% CIs 27.9 to 40.9), self-caring (ORs=25.0, 95% CIs 20.3 to 30.8) as well as communicating (ORs=194.5, 95% CIs 154.0 to 247.8). We observed a similar trend in all the three age-groups considered - ‘0-14’, ‘15-64’, and ‘65+’ years. Interpretation: Deaf persons are experiencing significantly poorer health than the rest of the population, and experience potentially preventable loss of function in relation to mobility, sight, cognition, communication, and self-caring. This loss of functioning could be prevented. Poor health outcomes experienced by deaf persons are underpinned by health disparities in key areas of health, such as population coverage and service coverage, as well as the prevalence of chronic illness. Funding Information: This work was possible because of the Swiss National Science Foundation (SNF) grant no PZ00P1_186035. OK was funded by the SNF (grant no 202660).Declaration of Interests: Authors have no conflict of interest to declare.Ethics Approval Statement: The research protocol was approved by the ethics committee of the University of Geneva CUREG_2021-05-50.

The epithelial to mesenchymal transition (EMT) has been proposed to contribute to the metastatic spread of breast cancer cells. EMT-promoting transcription factors determine a continuum of different EMT states. In contrast, estrogen receptor α (ERα) helps to maintain the epithelial phenotype of breast cancer cells and its expression is crucial for effective endocrine therapies. Determining whether and how EMT-associated transcription factors such as ZEB1 modulate ERα signaling during early stages of EMT could promote the discovery of therapeutic approaches to suppress metastasis. Here we show that, shortly after induction of EMT and while cells are still epithelial, ZEB1 modulates ERα-mediated transcription induced by estrogen or cAMP signaling in breast cancer cells. Based on these findings and our ex vivo and xenograft results, we suggest that the functional interaction between ZEB1 and ERα may alter the tissue tropism of metastatic breast cancer cells towards bone.

Locomotor sensitization (LS) is an early behavioral adaptation to addictive drugs, driven by the increase of dopamine in the Nucleus Accumbens (NAc). However, the effect on accumbal population activity remains elusive. Here, we used single-cell calcium imaging in mice to record the activity of dopamine-1-receptor (D1R) and dopamine-2-receptor (D2R) expressing spiny projection neurons (SPNs) during cocaine LS. Acute exposure to cocaine elevated D1R SPN activity and reduced D2R SPN activity, albeit with high variability between neurons. During LS, the number of D1R and D2R neurons responding in opposite directions increased. Moreover, preventing LS by inhibition of the ERK signaling pathway decreased the number of cocaine responsive D1R SPNs, but had little effect on D2R SPNs. These results indicate that accumbal population dichotomy is dynamic and contains a subgroup of D1R SPNs that eventually drives LS. Insights into the drug-related activity dynamics provides a foundation for understanding the circuit-level addiction pathogenesis.

Understanding the window of infectiousness for SARS-CoV-2 is essential for infection control measures. RT-PCR remains the gold standard for diagnosis but cannot inform on the presence of infectious virus, which can only be determined via inoculating cultured cells. Such findings are crucial for estimating infectiousness.1Jones TC Biele G Mühlemann B et al.Estimating infectiousness throughout SARS-CoV-2 infection course.Science. 2021; 373eabi5273Crossref PubMed Scopus (261) Google Scholar Although the process of virus transmission is multifactorial, viral load and successful isolation of the virus are most closely associated with the likelihood of transmission. However, studies estimating the probability of virus isolation were primarily done in Vero E6 cells, and found a strongly reduced success of isolation when the viral load was below 5–7 log10 RNA copies per mL or after more than 1 week of symptoms.2Wölfel R Corman VM Guggemos W et al.Virological assessment of hospitalized patients with COVID-2019.Nature. 2020; 581: 465-469Crossref PubMed Scopus (4501) Google Scholar, 3van Kampen JJA van de Vijver DAMC Fraaij PLA et al.Duration and key determinants of infectious virus shedding in hospitalized patients with coronavirus disease-2019 (COVID-19).Nat Commun. 2021; 12: 267Crossref PubMed Scopus (416) Google Scholar, 4Perera RAPM Tso E Tsang OTY et al.SARS-CoV-2 virus culture and subgenomic RNA for respiratory specimens from patients with mild coronavirus disease.Emerg Infect Dis. 2020; 26: 2701-2704Crossref PubMed Scopus (159) Google Scholar Although Vero E6 cells are highly susceptible to SARS-CoV-2 and widely used for isolation, they do not mimic the primary site of entry in the human respiratory tract. To assess presence of infectious SARS-CoV-2 in a more relevant model, we investigated virus isolation on Vero E6 and human primary airway epithelial cells in parallel, with viral load quantified with the WHO International Standard for SARS-CoV-2 RNA (National Institute for Biological Standards and Control code: 20/146).5Bentley E Mee ET Routley S et al.WHO/BS.2020.2402 collaborative study for the establishment of a WHO international standard for SARS-CoV-2 RNA. World Health Organization, GenevaNov 18, 2020Google Scholar In 39 clinical samples (nasopharyngeal swabs of adults positive for SARS-CoV-2 within 5 days of symptom onset) with viral loads of 4·5–8·8 log10 SARS-CoV-2 international units (IUs) per mL, virus isolation was successful for 27 (69%) samples in Vero E6 cells and 12 (31%) samples in airway epithelial cells (appendix). Using Probit analysis, the probability of virus isolation was below 5% when viral load was lower than 4·8 log10 IU/mL (95% CI 4·6–5·3) in Vero E6 cells, and 5·5 log10 IU/mL (4·9–6·1) in airway epithelial cells (p<0·05). Differences in the probability of virus isolation were highest between 5·5 and 7·5 IU/mL in Vero E6 cells versus airway epithelial cells (appendix). Overall Vero E6 cells were more permissive for SARS-CoV-2 infection than airway epithelial cells, allowing virus isolation in samples with lower viral load (appendix). This finding could indicate that actual infectiousness, transmissibility, and virus shedding in human cells in vivo are slightly overestimated when the presence of infectious virus is determined using Vero E6 cells. This conclusion is limited by the fact that viral loads and virus isolation do not fully equate to infectiousness in vivo. Because the assessment of successful virus isolation and viral load quantification can vary between laboratories, depending on protocols, samples, and materials used, the strength of our study is the use of viral load standardised by IU and parallel isolation of the same clinical sample in two cell culture systems. Our study emphasises the importance of the cell lines used for SARS-CoV-2 culture and supports the use of models closely mimicking the in-vivo situation for better understanding of SARS-CoV-2 transmission risks. We declare no competing interests. We thank Catia Alvarez and Pascale Sattonnet-Roche for excellent technical support and Erik Boehm for language editing. This work was supported by the Private HUG Foundation, by the Pictet Charitable Foundation and by the Swiss National Science Foundation (196644, 196383). Download .pdf (.52 MB) Help with pdf files Supplementary appendix

Comparison of virus isolation success from clinical samples across a range of viral loads inoculated in parallel on Vero E6 and human airway epithelia (HAE) showed lower success of virus isolation in HAE, suggesting an overestimation of actual infectiousness in humans using Vero E6 cell lines, commonly considered as reference.

A significant fraction of the glycerophospholipids in the human body is composed of plasmalogens, particularly in the brain, cardiac, and immune cell membranes. A decline in these lipids has been observed in such diseases as Alzheimer's and chronic obstructive pulmonary disease. Plasmalogens contain a characteristic 1-O-alk-1'-enyl ether (vinyl ether) double bond that confers special biophysical, biochemical, and chemical properties to these lipids. However, the genetics of their biosynthesis is not fully understood, since no gene has been identified that encodes plasmanylethanolamine desaturase (E.C. 1.14.99.19), the enzyme introducing the crucial alk-1'-enyl ether double bond. The present work identifies this gene as transmembrane protein 189 (TMEM189). Inactivation of the TMEM189 gene in human HAP1 cells led to a total loss of plasmanylethanolamine desaturase activity, strongly decreased plasmalogen levels, and accumulation of plasmanylethanolamine substrates and resulted in an inability of these cells to form labeled plasmalogens from labeled alkylglycerols. Transient expression of TMEM189 protein, but not of other selected desaturases, recovered this deficit. TMEM189 proteins contain a conserved protein motif (pfam10520) with eight conserved histidines that is shared by an alternative type of plant desaturase but not by other mammalian proteins. Each of these histidines is essential for plasmanylethanolamine desaturase activity. Mice homozygous for an inactivated Tmem189 gene lacked plasmanylethanolamine desaturase activity and had dramatically lowered plasmalogen levels in their tissues. These results assign the TMEM189 gene to plasmanylethanolamine desaturase and suggest that the previously characterized phenotype of Tmem189-deficient mice may be caused by a lack of plasmalogens.

Circadian regulation of transcriptional processes has a broad impact on cell metabolism. Here, we compared the diurnal transcriptome of human skeletal muscle conducted on serial muscle biopsies in vivo with profiles of human skeletal myotubes synchronized in vitro. More extensive rhythmic transcription was observed in human skeletal muscle compared to in vitro cell culture as a large part of the in vivo mRNA rhythmicity was lost in vitro. siRNA-mediated clock disruption in primary myotubes significantly affected the expression of ~8% of all genes, with impact on glucose homeostasis and lipid metabolism. Genes involved in GLUT4 expression, translocation and recycling were negatively affected, whereas lipid metabolic genes were altered to promote activation of lipid utilization. Moreover, basal and insulin-stimulated glucose uptake were significantly reduced upon CLOCK depletion. Our findings suggest an essential role for the circadian coordination of skeletal muscle glucose homeostasis and lipid metabolism in humans.

Mitochondrial gene expression is a fundamental process that is largely dependent on nuclear-encoded proteins. Several steps of mitochondrial RNA processing and maturation, including RNA post-transcriptional modification, appear to be spatially organized into distinct foci, which we have previously termed mitochondrial RNA granules (MRGs). Although an increasing number of proteins have been localized to MRGs, a comprehensive analysis of the proteome of these structures is still lacking. Here, we have applied a microscopy-based approach that has allowed us to identify novel components of the MRG proteome. Among these, we have focused our attention on RPUSD4, an uncharacterized mitochondrial putative pseudouridine synthase. We show that RPUSD4 depletion leads to a severe reduction of the steady-state level of the 16S mitochondrial (mt) rRNA with defects in the biogenesis of the mitoribosome large subunit and consequently in mitochondrial translation. We report that RPUSD4 binds 16S mt-rRNA, mt-tRNAMet, and mt-tRNAPhe, and we demonstrate that it is responsible for pseudouridylation of the latter. These data provide new insights into the relevance of RNA pseudouridylation in mitochondrial gene expression.

Glioblastoma is a highly heterogeneous aggressive primary brain tumor, with the glioma stem‐like cells ( GSC ) being more sensitive to cytotoxic lymphocyte‐mediated killing than glioma differentiated cells ( GDC ). However, the mechanism behind this higher sensitivity is unclear. Here, we found that the mitochondrial morphology of GSC s modulates the ER –mitochondria contacts that regulate the surface expression of sialylated glycans and their recognition by cytotoxic T lymphocytes and natural killer cells. GSC s displayed diminished ER –mitochondria contacts compared to GDC s. Forced ER –mitochondria contacts in GSC s increased their cell surface expression of sialylated glycans and reduced their susceptibility to cytotoxic lymphocytes. Therefore, mitochondrial morphology and dynamism dictate the ER –mitochondria contacts in order to regulate the surface expression of certain glycans and thus play a role in GSC recognition and elimination by immune effector cells. Targeting the mitochondrial morphology, dynamism, and contacts with the ER could be an innovative strategy to deplete the cancer stem cell compartment to successfully treat glioblastoma.

Venom based research is exploited to find novel candidates for the development of innovative pharmacological tools, drug candidates and new ingredients for cosmetic and agrochemical industries. Moreover, venomics, as a well-established approach in systems biology, helps to elucidate the genetic mechanisms of the production of such a great molecular biodiversity. Today the advances made in the proteomics, transcriptomics and bioinformatics fields, favor venomics, allowing the in depth study of complex matrices and the elucidation even of minor compounds present in minute biological samples. The present study illustrates a rapid and efficient method developed for the elucidation of venom composition based on NextGen mRNA sequencing of venom glands and LC-MS/MS venom proteome profiling. The analysis of the comprehensive data obtained was focused on cysteine rich peptide toxins from four spider species originating from phylogenetically distant families for comparison purposes. The studied species were Heteropoda davidbowie (Sparassidae), Poecilotheria formosa (Theraphosidae), Viridasius fasciatus (Viridasiidae) and Latrodectus mactans (Theridiidae). This led to a high resolution profiling of 284 characterized cysteine rich peptides, 111 of which belong to the Inhibitor Cysteine Knot (ICK) structural motif. The analysis of H. davidbowie venom revealed a high richness in term of venom diversity: 95 peptide sequences were identified; out of these, 32 peptides presented the ICK structural motif and could be classified in six distinct families. The profiling of P. formosa venom highlighted the presence of 126 peptide sequences, with 52 ICK toxins belonging to three structural distinct families. V. fasciatus venom was shown to contain 49 peptide sequences, out of which 22 presented the ICK structural motif and were attributed to five families. The venom of L. mactans, until now studied for its large neurotoxins (Latrotoxins), revealed the presence of 14 cysteine rich peptides, out of which five were ICK toxins belonging to the CSTX superfamily. This in depth profiling of distinct ICK peptide families identified across the four spider species highlighted the high conservation of these neurotoxins among spider families.

Covalent modifications of histones play a crucial role in the regulation of gene expression. Histone H2B monoubiquitination has mainly been described as a regulator of transcription elongation, but its role in transcription initiation is poorly documented. We investigated the role of this histone mark (H2Bub1) on different inducible enhancers, in particular those regulated by estrogen receptor α, by loss- and gain-of-function experiments with the specific E3-ubiquitin ligase complex of H2B: RNF20/RNF40. RNF20/RNF40 overexpression causes repression of the induced activity of these enhancers. Genome-wide profiles show that H2Bub1 levels are negatively correlated with the accessibility of enhancers to transcriptional activators. We found that the chromatin association of histone variant H2A.Z, which is evicted from enhancers for transcriptional activation, is stabilized by H2Bub1 by impairing access of the chromatin remodeler INO80. We propose that H2Bub1 acts as a gatekeeper of H2A.Z eviction and activation of inducible enhancers.

Marine cone snail venoms are highly complex mixtures of peptides and proteins. They have been studied in-depth over the past 3 decades, but the modus operandi of the venomous apparatus still remains unclear. Using the fish-hunting Conus consors as a model, we present an integrative venomics approach, based on new proteomic results from the venom gland and data previously obtained from the transcriptome and the injectable venom. We describe here the complete peptide content of the dissected venom by the identification of numerous new peptides using nanospray tandem mass spectrometry in combination with transcriptomic data. Results reveal extensive mature peptide diversification mechanisms at work in the venom gland. In addition, by integrating data from three different venom stages, transcriptome, dissected, and injectable venoms, from a single species, we obtain a global overview of the venom processing that occurs from the venom gland tissue to the venom delivery step. In the light of the successive steps in this venom production system, we demonstrate that each venom compartment is highly specific in terms of peptide and protein content. Moreover, the integrated investigative approach discussed here could become an essential part of pharmaceutical development, as it provides new potential drug candidates and opens the door to numerous analogues generated by the very mechanisms used by nature to diversify its peptide and protein arsenal.