Relationships between emotion regulation strategies and executive functions in adolescence: Exploring the effects of discrete emotions and age

INTRODUCTION

Emotion regulation (ER) develops during adolescence and contributes to psychosocial adjustment. Individual differences in the development of ER strategies may be related to cognitive processes responsible for managing goal-directed behaviors, namely executive functions (EFs). This study examined (1) examined how difficulties in specific EFs (i.e., inhibition, flexibility and working memory) predict the use of ER strategies (i.e., reappraisal, distraction, expressive suppression, rumination, support-seeking) in an emotion-specific approach and (2) investigated these links across three different age groups (corresponding to early, middle and late adolescence), considering the nonlinear evolution of the relationships between EF and ER strategies during adolescence.

METHODS

The sample was composed of 1076 adolescents aged from 12 to 19 years old who completed questionnaires on EF difficulties (i.e., inhibition, flexibility, and working memory) and ER strategies (i.e., distraction, reappraisal, expressive suppression, social support-seeking, and rumination).

RESULTS

Results showed various complex relationships between EFs and ER. Flexibility issues were related to rumination at all ages, while inhibition and flexibility difficulties were negatively linked to reappraisal in mid- to late adolescence. Many relationships were emotion- and age-dependent.

CONCLUSIONS

These findings support the link between cognitive and emotional regulatory processes. Its complex evolution during adolescence opens a new avenue for future research.

Eomes-dependent mitochondrial regulation promotes survival of pathogenic CD4+ T cells during inflammation

The mechanisms whereby Eomes controls tissue accumulation of T cells and strengthens inflammation remain ill-defined. Here, we show that Eomes deletion in antigen-specific CD4+ T cells is sufficient to protect against central nervous system (CNS) inflammation. While Eomes is dispensable for the initial priming of CD4+ T cells, it is required for long-term maintenance of CNS-infiltrating CD4+ T cells. We reveal that the impact of Eomes on effector CD4+ T cell longevity is associated with sustained expression of multiple genes involved in mitochondrial organization and functions. Accordingly, epigenetic studies demonstrate that Eomes supports mitochondrial function by direct binding to either metabolism-associated genes or mitochondrial transcriptional modulators. Besides, the significance of these findings was confirmed in CD4+ T cells from healthy donors and multiple sclerosis patients. Together, our data reveal a new mechanism by which Eomes promotes severity and chronicity of inflammation via the enhancement of CD4+ T cell mitochondrial functions and resistance to stress-induced cell death.

BSV163/DOPE-mediated TRAIL gene transfection acts synergistically with chemotherapy against cisplatin-resistant ovarian cancer

Ovarian cancer is the seventh most frequently diagnosed cancer among women worldwide. Most patients experience recurrence and succumb eventually to resistant disease, underscoring the need for an alternative treatment option. In the presented manuscript, we investigated the effect of the TRAIL-gene, transfected by an innovative bioinspired lipid vector BSV163/DOPE in the presence or absence of cisplatin, to fight against sensitive and resistant ovarian cancer. We showed that BSV163/DOPE can transfect ovarian cancer cell lines (Caov3, OVCAR3, and our new cisplatin-resistant, CR-Caov3) safely and efficiently. In addition, TRAIL-gene transfection in association with cisplatin inhibited cellular growth more efficiently (nearly 50% in Caov3 cells after the combined treatment, and 15% or 25% by each treatment alone, respectively) owing to an increase in apoptosis rate, caspases activity and TRAIL's death receptors expression. Most importantly, such synergistic effect was also observed in CR-Caov3 cells demonstrated by an apoptosis rate of 35% following the combined treatment in comparison with 17% after TRAIL-gene transfection or 6% after cisplatin exposition. These results suggest this combination may have potential application for sensitive as well as refractory ovarian cancer patients.

Diagnosis with confidence: deep learning for reliable classification of laryngeal dysplasia

BACKGROUND

Diagnosis of head and neck (HN) squamous dysplasias and carcinomas is critical for patient care, cure, and follow-up. It can be challenging, especially for grading intraepithelial lesions. Despite recent simplification in the last WHO grading system, the inter- and intraobserver variability remains substantial, particularly for nonspecialized pathologists, exhibiting the need for new tools to support pathologists.

METHODS

In this study we investigated the potential of deep learning to assist the pathologist with automatic and reliable classification of HN lesions following the 2022 WHO classification system. We created, for the first time, a large-scale database of histological samples (>2000 slides) intended for developing an automatic diagnostic tool. We developed and trained a weakly supervised model performing classification from whole-slide images (WSI). We evaluated our model on both internal and external test sets and we defined and validated a new confidence score to assess the predictions that can be used to identify difficult cases.

RESULTS

Our model demonstrated high classification accuracy across all lesion types on both internal and external test sets (respectively average area under the curve [AUC]: 0.878 (95% confidence interval [CI]: [0.834-0.918]) and 0.886 (95% CI: [0.813-0.947])) and the confidence score allowed for accurate differentiation between reliable and uncertain predictions.

CONCLUSION

Our results demonstrate that the model, associated with confidence measurements, can help in the difficult task of classifying HN squamous lesions by limiting variability and detecting ambiguous cases, taking us one step closer to a wider adoption of AI-based assistive tools.

ProbaStem, a pipeline towards the first high-resolution probabilistic atlas of the whole human brainstem

The brainstem plays an essential role in many vital functions, such as autonomic control, consciousness and sleep, motricity, somatic afferent function, and cognition. Its involvement in several neurological diseases and the definition of brainstem targets for deep brain stimulation (DBS) explain the need for brainstem atlases describing its structural organization and connectivity from several modalities, from histology to ultrahigh field ex vivo MRI. Nonetheless, these atlases are often limited to a subpart of the brainstem or only include a single subject, the brainstem variability being considered low. This paper proposes a pipeline to create a high-resolution multisubject probabilistic atlas of the whole human brainstem based on four ultrahigh field ex vivo MRI datasets. The variability of the brainstem structures appears higher than usually considered, both for the volume and position of the central gray matter structures of the brainstem. This justifies the creation of atlases that capture the anatomical variability across subjects. The one we present here only included four specimens, but can easily be incremented due to its highly flexible design.

Uncertainty in the association between socio-demographic characteristics and mental health

Questionnaires are among the most basic and widespread tools to assess the mental health of a population in epidemiological and public health studies. Their most obvious advantage (firsthand self-report) is also the source of their main problems: the raw data requires interpretation, and are a snapshot of the specific sample's status at a given time. Efforts to deal with both issues created a bi-dimensional space defined by two orthogonal axes, in which most of the quantitative mental health research can be located. Methods aimed to assure that mental health diagnoses are solidly grounded on existing raw data are part of the individual validity axis. Tools allowing the generalization of the results across the entire population compose the collective validity axis. This paper raises a different question. Since one goal of mental health assessments is to obtain results that can be generalized to some extent, an important question is how robust is a questionnaire result when applied to a different population or to the same population at a different time. In this case, there is deep uncertainty, without any a priori probabilistic information. The main claim of this paper is that this task requires the development of a new robustness to deep uncertainty axis, defining a three-dimensional research space. We demonstrate the analysis of deep uncertainty using the concept of robustness in info-gap decision theory. Based on data from questionnaires collected before and during the Covid-19 pandemic, we first locate a mental health assessment in the space defined by the individual validity axis and the collective validity axis. Then we develop a model of info-gap robustness to uncertainty in mental health assessment, showing how the robustness to deep uncertainty axis interacts with the other two axes, highlighting the contributions and the limitations of this approach. The ability to measure robustness to deep uncertainty in the mental health realm is important particularly in troubled and changing times. In this paper, we provide the basic methodological building blocks of the suggested approach using the outbreak of Covid-19 as a recent example.

Resolving a guanine-quadruplex structure in the SARS-CoV-2 genome through circular dichroism and multiscale molecular modeling

The genome of SARS-CoV-2 coronavirus is made up of a single-stranded RNA fragment that can assume a specific secondary structure, whose stability can influence the virus's ability to reproduce. Recent studies have identified putative guanine quadruplex sequences in SARS-CoV-2 genome fragments that are involved in coding for both structural and non-structural proteins. In this contribution, we focus on a specific G-rich sequence referred to as RG-2, which codes for the non-structural protein 10 (Nsp10) and assumes a guanine-quadruplex (G4) arrangement. We provide the secondary structure of RG-2 G4 at atomistic resolution by molecular modeling and simulation, validated by the superposition of experimental and calculated electronic circular dichroism spectra. Through both experimental and simulation approaches, we have demonstrated that pyridostatin (PDS), a widely recognized G4 binder, can bind to and stabilize RG-2 G4 more strongly than RG-1, another G4 forming sequence that was previously proposed as a potential target for antiviral drug candidates. Overall, this study highlights RG-2 as a valuable target to inhibit the translation and replication of SARS-CoV-2, paving the way towards original therapeutic approaches against emerging RNA viruses.

Asymmetric Allenylation of Alkynes mediated by Chiral Organoselenated Reagents under Oxidative Conditions

The reactivity of novel chiral lactamide-substituted diselenide-based reagents under oxidative conditions was exploited to develop a metal-free method for the preparation of enantioenriched allenylamides from simple alkynes in good yields, and with enantiomeric excesses up to 99 %. The key of the success in this method is attributed to the hydrogen-bonded lactamide appendages that ensure configurational stability of chiral vinyl selenoxide intermediates for an optimal enantiotopic β-syn-elimination step.

Interaction Between the Transferrin Protein and Plutonium (and Thorium), What's New?

Transferrin (Tf) is a glycoprotein that transports iron from the serum to the various organs. Several studies have highlighted that Tf can interact with metals other than Fe(III), including actinides that are chemical and radiological toxics. We propose here to report on the behavior of Th(IV) and Pu(IV) in comparison with Fe(III) upon Tf complexation. We considered UV-Vis and IR data of the M2 Tf complex (M=Fe, Th, Pu) and combined experimental EXAFS data with MD models. EXAFS data of the first M-O coordination sphere are consistent with the MD model considering 1 synergistic carbonate. Further EXAFS data analysis strongly suggests that contamination by Th/Pu colloids seems to occur upon Tf complexation, but it seems limited. SAXS data have also been recorded for all complexes and also after the addition of Deferoxamine-B (DFOB) in the medium. The Rg values are very close for apoTf, ThTf and PuTf, but slightly larger than for holoTf. Data suggest that the structure of the protein is more ellipsoidal than spherical, with a flattened oblate form. From this data, the following order of conformation size might be considered:holoTf Collapse

Key Words

• Plutonium
• SAX
• Transferrin
• XAS
• metalloprotein

Collapse

MESH Headings

• Transferrin/chemistry
• Plutonium/chemistry
• Thorium/chemistry
• Ferric Compounds
• Scattering, Small Angle
• X-Ray Diffraction

Collapse

Grants

• Ministère de l'Enseignement supérieur, de la Recherche et de l'Innovation

Collapse

Affiliation(s)

Cyril Zurita Université Côte d'Azur, CNRS, Institut de Chimie de Nice, 06108, Nice, France
Satoru Tsushima Institute of Resource Ecology, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328, Dresden, Germany Internationnal Research Frontiers Initiative, Institute of Innovative Research, Tokyo Institute of Technology, Meguro, 152-8550, Tokyo, Japan
Pier Lorenzo Solari Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint Aubin, France
Denis Menut Synchrotron SOLEIL, L'Orme des Merisiers, 91190, Saint Aubin, France
Sandrine Dourdain ICSM, Université de Montpellier, CEA, CNRS, ENSCM, Marcoule, France
Aurélie Jeanson Université Côte d'Azur, CNRS, Institut de Chimie de Nice, 06108, Nice, France
Gaëlle Creff Université Côte d'Azur, CNRS, Institut de Chimie de Nice, 06108, Nice, France
Christophe Den Auwer Université Côte d'Azur, CNRS, Institut de Chimie de Nice, 06108, Nice, France

Collapse

Health and Social Case Management for the Inclusion of People Living with a Schizophrenic Disorder: The PASSVers Experience

The way the social protection system in France is organized frequently leads to coordination difficulties between the social and healthcare sectors. A health and social program has been implemented in a French medical-psychological center to optimize the coherence of the pathway for people living with schizophrenia. This study evaluated the way users and professionals perceive this program so as to assess the relevance of double case management. Semi-structured interviews were conducted with users (N = 21) and professionals (N = 11) of this program and then analyzed with Alceste software. The results highlight the overall satisfaction of the participants with the program, and the double case management was shown to be beneficial in supporting people living with schizophrenia in their life project. These results indicate that this program enabled the emergence of a collective empowerment, which could assist with the recovery process of schizophrenia.

Contribution of dorsal versus ventral hippocampus to the hierarchical modulation of goal-directed actions in rats

Adaptive behaviour often necessitates that animals learn about events in a manner that is specific to a particular context or environment. These hierarchical organisations allow the animal to decide which action is the most appropriate when faced with ambiguous or conflicting possibilities. This study examined the role of hippocampus in enabling animals to use the context to guide action selection. We used a hierarchical instrumental outcome devaluation task in which male rats learn that the context provides information about the unique action-outcome relations that are in effect. We first confirmed that rats encode and use hierarchical context-(action-outcome) relations. We then show that chemogenetic inhibition of ventral hippocampus impairs both the encoding and retrieval of these associations, while inhibition of dorsal hippocampus impairs only the retrieval. Importantly, neither dorsal nor ventral hippocampus was required for goal-directed behaviour per se as these impairments only emerged when rats were forced to use the context to identify the current action-outcome relationships. These findings are discussed with respect to the role of the hippocampus and its broader circuitry in the contextual modulation of goal-directed behaviour and the importance of hierarchical associations in flexible behaviour.

Characteristic response of formulation ingredients revealed by ultra high performance liquid chromatography-electrospray ionization-high resolution mass spectrometry-based untargeted screening of pesticides in soil

Commercial solutions of pesticides consist of two main components: The active substance and the formulation ingredients. These ingredients, mainly composed of polymeric surfactants, are considered inert vis-à-vis the targeted organisms and nature. Nonetheless, a relatively low attention is given to their analysis and fate tracking in the environment. In this context, the current paper, embedded in a large study of fate and impact of formulated pesticides in soil, focuses on the analysis of these formulation ingredients. It mainly highlights and discusses the characteristic response of these ingredients in liquid chromatography-mass spectrometry-based untargeted screening of two commercial herbicides applied on soil. This characteristic response is based on different spectral and chromatographic aspects, as their amplified adducts and double-charged ions formation, or their "wavy" chromatographic profiles and the inversion of their elution order following the polymerization degree. These patterns are briefly discussed in order to explain them, and then thanks to their understanding, 12 different series (165 compounds) of formulation ingredients were outlined and discriminated from active substance and soil metabolites. After, high-resolution and tandem mass spectrometry data were investigated for rapid interseries and intraseries identification-by-chain. In addition, recommendations for methods development and hints on postanalytical data processing for identity determination of these ingredients are given in order to help in enhancing future studies. Limitations of the applied approach are also outlined, and some innovate suggestions are provided based on the described findings.

Multimodal Communication in the Human-Cat Relationship: A Pilot Study

Across all species, communication implies that an emitter sends signals to a receiver, through one or more channels. Cats can integrate visual and auditory signals sent by humans and modulate their behaviour according to the valence of the emotion perceived. However, the specific patterns and channels governing cat-to-human communication are poorly understood. This study addresses whether, in an extraspecific interaction, cats are sensitive to the communication channel used by their human interlocutor. We examined three types of interactions-vocal, visual, and bimodal-by coding video clips of 12 cats living in cat cafés. In a fourth (control) condition, the human interlocutor refrained from emitting any communication signal. We found that the modality of communication had a significant effect on the latency in the time taken for cats to approach the human experimenter. Cats interacted significantly faster to visual and bimodal communication compared to the "no communication" pattern, as well as to vocal communication. In addition, communication modality had a significant effect on tail-wagging behaviour. Cats displayed significantly more tail wagging when the experimenter engaged in no communication (control condition) compared to visual and bimodal communication modes, indicating that they were less comfortable in this control condition. Cats also displayed more tail wagging in response to vocal communication compared to the bimodal communication. Overall, our data suggest that cats display a marked preference for both visual and bimodal cues addressed by non-familiar humans compared to vocal cues only. Results arising from the present study may serve as a basis for practical recommendations to navigate the codes of human-cat interactions.

Long term worsening of amyloid pathology, cerebral function, and cognition after a single inoculation of beta-amyloid seeds with Osaka mutation

Alzheimer's disease (AD) is characterized by intracerebral deposition of abnormal proteinaceous assemblies made of amyloid-β (Aß) peptides or tau proteins. These peptides and proteins induce synaptic dysfunctions that are strongly correlated with cognitive decline. Intracerebral infusion of well-defined Aβ seeds from non-mutated Aβ_1-40 or Aβ_1-42 peptides can increase Aβ depositions several months after the infusion. Familial forms of AD are associated with mutations in the amyloid precursor protein (APP) that induce the production of Aβ peptides with different structures. The Aβ Osaka (Aβ_osa mutation (E693Δ)) is located within the Aβ sequence and thus the Aβ_osa peptides have different structures and properties as compared to non-mutated Aβ_1-42 peptides (Aβ_wt). Here, we wondered if a single exposure to this mutated Aβ can worsen AD pathology as well as downstream events including cognition, cerebral connectivity and synaptic health several months after the inoculation. To answer this question we inoculated Aβ_1-42-bearing Osaka mutation (Aβ_osa) in the dentate gyrus of APP_swe/PS1_dE9 mice at the age of two months. Their cognition and cerebral connectivity were analyzed at 4 months post-inoculation by behavioral evaluation and functional MRI. Aβ pathology as well as synaptic density were evaluated by histology. The impact of Aβ_osa peptides on synaptic health was also measured on primary cortical neurons. Remarkably, the intracerebral administration of Aβ_osa induced cognitive and synaptic impairments as well as a reduction of functional connectivity between different brain regions, 4 months post-inoculation. It increased Aβ plaque depositions and increased Aβ oligomers. This is the first study showing that a single, sporadic event as Aβ_osa inoculation can worsen the fate of the pathology and clinical outcome several months after the event. It suggests that a single inoculation of Aβ regulates a large cascade of events for a long time.

Current distribution of distributed all-polar cochlear implant stimulation mode measured in-situ

Oticon Medical cochlear implants use a stimulation mode called Distributed All-Polar (DAP) that connects all non-stimulating available intracochlear electrodes and an extracochlear reference electrode. It results in a complex distribution of current that is yet undescribed. The present study aims at providing a first characterization of this current distribution. A Neuro Zti was modified to allow the measurement of current returning to each electrode during a DAP stimulation and was implanted in an ex-vivo human head. Maps of distributed current were then created for different stimulation conditions with different charge levels. Results show that, on average, about 20% of current returns to the extracochlear reference electrode, while the remaining 80% is distributed between intracochlear electrodes. The position of the stimulating electrode changed this ratio, and about 10% more current to the extracochlear return in case of the first 3 basal electrodes than for apical and mid position electrodes was observed. Increasing the charge level led to small but significant change in the ratio, and about 4% more current to the extracochlear return was measured when increasing the charge level from 11.7 to 70 nC. Further research is needed to show if DAP yields better speech understanding than other stimulation modes.

PAI-1 production by reactive astrocytes drives tissue dysfibrinolysis in multiple sclerosis models

BACKGROUND

In multiple sclerosis (MS), disturbance of the plasminogen activation system (PAS) and blood brain barrier (BBB) disruption are physiopathological processes that might lead to an abnormal fibrin(ogen) extravasation into the parenchyma. Fibrin(ogen) deposits, usually degraded by the PAS, promote an autoimmune response and subsequent demyelination. However, the PAS disruption is not well understood and not fully characterized in this disorder.

METHODS

Here, we characterized the expression of PAS actors during different stages of two mouse models of MS (experimental autoimmune encephalomyelitis-EAE), in the central nervous system (CNS) by quantitative RT-PCR, immunohistofluorescence and fluorescent in situ hybridization (FISH). Thanks to constitutive PAI-1 knockout mice (PAI-1 KO) and an immunotherapy using a blocking PAI-1 antibody, we evaluated the role of PAI-1 in EAE models and its impact on physiopathological processes such as fibrin(ogen) deposits, lymphocyte infiltration and demyelination.

RESULTS

We report a striking overexpression of PAI-1 in reactive astrocytes during symptomatic phases, in two EAE mouse models of MS. This increase is concomitant with lymphocyte infiltration and fibrin(ogen) deposits in CNS parenchyma. By genetic invalidation of PAI-1 in mice and immunotherapy using a blocking PAI-1 antibody, we demonstrate that abolition of PAI-1 reduces the severity of EAE and occurrence of relapses in two EAE models. These benefits are correlated with a decrease in fibrin(ogen) deposits, infiltration of T4 lymphocytes, reactive astrogliosis, demyelination and axonal damage.

CONCLUSION

These results demonstrate that a deleterious overexpression of PAI-1 by reactive astrocytes leads to intra-parenchymal dysfibrinolysis in MS models and anti-PAI-1 strategies could be a new therapeutic perspective for MS.

Three classes of epigenomic regulators converge to hyperactivate the essential maternal gene deadhead within a heterochromatin mini-domain

The formation of a diploid zygote is a highly complex cellular process that is entirely controlled by maternal gene products stored in the egg cytoplasm. This highly specialized transcriptional program is tightly controlled at the chromatin level in the female germline. As an extreme case in point, the massive and specific ovarian expression of the essential thioredoxin Deadhead (DHD) is critically regulated in Drosophila by the histone demethylase Lid and its partner, the histone deacetylase complex Sin3A/Rpd3, via yet unknown mechanisms. Here, we identified Snr1 and Mod(mdg4) as essential for dhd expression and investigated how these epigenomic effectors act with Lid and Sin3A to hyperactivate dhd. Using Cut&Run chromatin profiling with a dedicated data analysis procedure, we found that dhd is intriguingly embedded in an H3K27me3/H3K9me3-enriched mini-domain flanked by DNA regulatory elements, including a dhd promoter-proximal element essential for its expression. Surprisingly, Lid, Sin3a, Snr1 and Mod(mdg4) impact H3K27me3 and this regulatory element in distinct manners. However, we show that these effectors activate dhd independently of H3K27me3/H3K9me3, and that dhd remains silent in the absence of these marks. Together, our study demonstrates an atypical and critical role for chromatin regulators Lid, Sin3A, Snr1 and Mod(mdg4) to trigger tissue-specific hyperactivation within a unique heterochromatin mini-domain.

Multicellular development depends on a tight control of gene expression in each cell type. This relies on the coordinated activities of nuclear proteins that interact with DNA or its histone scaffold to promote or restrict gene transcription. For example, we previously showed that the histone modifying enzymes Lid and Sin3A/Rpd3 are required in Drosophila ovaries for the massive expression of deadhead (dhd), a gene encoding for a thioredoxin that is essential for fertility. In this paper, we have further identified two additional dhd regulators, Snr1 and Mod(mdg4) and dissected the mechanism behind hyperactivation of this gene. Using the epigenomic profiling method Cut&Run with a dedicated data analysis approach, we unexpectedly found that dhd is embedded in an unusual chromatin mini-domain featuring repressive histone modifications H3K27me3 and H3K9me3 and flanked by two regulatory elements. However, we further showed that Lid, Sin3A, Snr1 and Mod(mdg4) behave like obligatory activators of dhd independently of this mini-domain. Our study unveils how multiple broad-acting epigenomic effectors operate in non-canonical manners to ensure a critical and specialized gene activation event. These findings challenge our knowledge on these regulatory mechanisms and their roles in development and pathology.

OUP accepted manuscript

MicroRNAs silence mRNAs by guiding the RISC complex. RISC assembly occurs following cleavage of pre-miRNAs by Dicer, assisted by TRBP or PACT, and the transfer of miRNAs to AGO proteins. The R2TP complex is an HSP90 co-chaperone involved in the assembly of ribonucleoprotein particles. Here, we show that the R2TP component RPAP3 binds TRBP but not PACT. The RPAP3-TPR1 domain interacts with the TRBP-dsRBD3, and the 1.5 Å resolution crystal structure of this complex identifies key residues involved in the interaction. Remarkably, binding of TRBP to RPAP3 or Dicer is mutually exclusive. Additionally, we found that AGO(1/2), TRBP and Dicer are all sensitive to HSP90 inhibition, and that TRBP sensitivity is increased in the absence of RPAP3. Finally, RPAP3 seems to impede miRNA activity, raising the possibility that the R2TP chaperone might sequester TRBP to regulate the miRNA pathway.

Use of systemic glucocorticoids and risk of breast cancer in a prospective cohort of postmenopausal women

BACKGROUND

Glucocorticoids could theoretically decrease breast cancer risk through their anti-inflammatory effects or increase risk through immunosuppression. However, epidemiological evidence is limited regarding the associations between glucocorticoid use and breast cancer risk.

METHODS

We investigated the association between systemic glucocorticoid use and breast cancer incidence in the E3N cohort, which includes 98,995 women with information on various characteristics collected from repeated questionnaires complemented with drug reimbursement data available from 2004. Women with at least two reimbursements of systemic glucocorticoids in any previous 3-month period since January 1, 2004, were defined as exposed. We considered exposure as a time-varying parameter, and we used multivariable Cox regression models to estimate hazard ratios (HRs) of breast cancer. We performed a competing risk analysis using a cause-specific hazard approach to study the heterogeneity by tumour subtype/stage/grade.

RESULTS

Among 62,512 postmenopausal women (median age at inclusion of 63 years old), 2864 developed breast cancer during a median follow-up of 9 years (between years 2004 and 2014). Compared with non-exposure, glucocorticoid exposure was not associated with overall breast cancer risk [HR = 0.94 (0.85-1.05)]; however, it was associated with a higher risk of in situ breast cancer and a lower risk of invasive breast cancer [HRinsitu = 1.34 (1.01-1.78); HRinvasive = 0.86 (0.76-0.97); Phomogeneity = 0.01]. Regarding the risk of invasive breast cancer, glucocorticoid exposure was inversely associated with oestrogen receptor (ER)-positive breast cancer [HRER+ = 0.82 (0.72-0.94); HRER- = 1.21 (0.88-1.66); Phomogeneity = 0.03]; it was also inversely associated with the risk of stage 1 or stage 2 tumours but positively associated with the risk of stage 3/4 breast cancers [HRstage1 = 0.87 (0.75-1.01); HRstage2 = 0.67 (0.52-0.86); HRstage3/4 = 1.49 (1.02-2.20); Phomogeneity = 0.01].

CONCLUSION

This study suggests that the association between systemic glucocorticoid use and breast cancer risk may differ by tumour subtype and stage.

GGGCTA repeats can fold into hairpins poorly unfolded by replication protein A: a possible origin of the length-dependent instability of GGGCTA variant repeats in human telomeres

Human telomeres are composed of GGGTTA repeats and interspersed with variant repeats. The GGGCTA variant motif was identified in the proximal regions of human telomeres about 10 years ago and was shown to display a length-dependent instability. In parallel, a structural study showed that four GGGCTA repeats folded into a non-canonical G-quadruplex (G4) comprising a Watson-Crick GCGC tetrad. It was proposed that this non-canonical G4 might be an additional obstacle for telomere replication. In the present study, we demonstrate that longer GGGCTA arrays fold into G4 and into hairpins. We also demonstrate that replication protein A (RPA) efficiently binds to GGGCTA repeats structured into G4 but poorly binds to GGGCTA repeats structured into hairpins. Our results (along with results obtained with a more stable variant motif) suggest that GGGCTA hairpins are at the origin of GGGCTA length-dependent instability. They also suggest, as working hypothesis, that failure of efficient binding of RPA to GGGCTA structured into hairpins might be involved in the mechanism of GGGCTA array instability. On the basis of our present and past studies about telomeric G4 and their interaction with RPA, we propose an original point of view about telomeric G4 and the evolution of telomeric motifs.

Association between menopausal hormone therapy, mammographic density and breast cancer risk: results from the E3N cohort study

BACKGROUND

Menopausal hormone therapy (MHT) is a risk factor for breast cancer (BC). Evidence suggests that its effect on BC risk could be partly mediated by mammographic density. The aim of this study was to investigate the relationship between MHT, mammographic density and BC risk using data from a prospective study.

METHODS

We used data from a case-control study nested within the French cohort E3N including 453 cases and 453 matched controls. Measures of mammographic density, history of MHT use during follow-up and information on potential confounders were available for all women. The association between MHT and mammographic density was evaluated by linear regression models. We applied mediation modelling techniques to estimate, under the hypothesis of a causal model, the proportion of the effect of MHT on BC risk mediated by percent mammographic density (PMD) for BC overall and by hormone receptor status.

RESULTS

Among MHT users, 4.2% used exclusively oestrogen alone compared with 68.3% who used exclusively oestrogens plus progestogens. Mammographic density was higher in current users (for a 60-year-old woman, mean PMD 33%; 95% CI 31 to 35%) than in past (29%; 27 to 31%) and never users (24%; 22 to 26%). No statistically significant association was observed between duration of MHT and mammographic density. In past MHT users, mammographic density was negatively associated with time since last use; values similar to those of never users were observed in women who had stopped MHT at least 8 years earlier. The odds ratio of BC for current versus never MHT users, adjusted for age, year of birth, menopausal status at baseline and BMI, was 1.67 (95% CI, 1.04 to 2.68). The proportion of effect mediated by PMD was 34% for any BC and became 48% when the correlation between BMI and PMD was accounted for. These effects were limited to hormone receptor-positive BC.

CONCLUSIONS

Our results suggest that, under a causal model, nearly half of the effect of MHT on hormone receptor-positive BC risk is mediated by mammographic density, which appears to be modified by MHT for up to 8 years after MHT termination.

Phytohormone production by the arbuscular mycorrhizal fungus Rhizophagus irregularis

Arbuscular mycorrhizal symbiosis is a mutualistic interaction between most land plants and fungi of the glomeromycotina subphylum. The initiation, development and regulation of this symbiosis involve numerous signalling events between and within the symbiotic partners. Among other signals, phytohormones are known to play important roles at various stages of the interaction. During presymbiotic steps, plant roots exude strigolactones which stimulate fungal spore germination and hyphal branching, and promote the initiation of symbiosis. At later stages, different plant hormone classes can act as positive or negative regulators of the interaction. Although the fungus is known to reciprocally emit regulatory signals, its potential contribution to the phytohormonal pool has received little attention, and has so far only been addressed by indirect assays. In this study, using mass spectrometry, we analyzed phytohormones released into the medium by germinated spores of the arbuscular mycorrhizal fungus Rhizophagus irregularis. We detected the presence of a cytokinin (isopentenyl adenosine) and an auxin (indole-acetic acid). In addition, we identified a gibberellin (gibberellin A₄) in spore extracts. We also used gas chromatography to show that R. irregularis produces ethylene from methionine and the α-keto γ-methylthio butyric acid pathway. These results highlight the possibility for AM fungi to use phytohormones to interact with their host plants, or to regulate their own development.

Targeting MHC Regulation Using Polycyclic Polyprenylated Acylphloroglucinols Isolated from Garcinia bancana

Modulation of major histocompatibility complex (MHC) expression using drugs has been proposed to control immunity. Phytochemical investigations on Garcinia species have allowed the isolation of bioactive compounds such as polycyclic polyprenylated acylphloroglucinols (PPAPs). PPAPs such as guttiferone J (1), display anti-inflammatory and immunoregulatory activities while garcinol (4) is a histone acetyltransferases (HAT) p300 inhibitor. This study reports on the isolation, identification and biological characterization of two other PPAPs, i.e., xanthochymol (2) and guttiferone F (3) from Garcinia bancana, sharing structural analogy with guttiferone J (1) and garcinol (4). We show that PPAPs 1-4 efficiently downregulated the expression of several MHC molecules (HLA-class I, -class II, MICA/B and HLA-E) at the surface of human primary endothelial cells upon inflammation. Mechanistically, PPAPs 1-4 reduce MHC proteins by decreasing the expression and phosphorylation of the transcription factor STAT1 involved in MHC upregulation mediated by IFN-γ. Loss of STAT1 activity results from inhibition of HAT CBP/p300 activity reflected by a hypoacetylation state. The binding interactions to p300 were confirmed through molecular docking. Loss of STAT1 impairs the expression of CIITA and GATA2 but also TAP1 and Tapasin required for peptide loading and transport of MHC. Overall, we identified new PPAPs issued from Garcinia bancana with potential immunoregulatory properties.

Allele mining unlocks the identification of RYMV resistance genes and alleles in African cultivated rice

BACKGROUND

Rice yellow mottle virus (RYMV) is a major rice pathogen in Africa. Three resistance genes, i.e. RYMV1, RYMV2 and RYMV3, have been previously described. RYMV1 encodes the translation initiation factor eIF(iso)4G1 and the best candidate genes for RYMV2 and RYMV3 encode a homolog of an Arabidopsis nucleoporin (CPR5) and a nucleotide-binding domain and leucine-rich repeat containing domain (NLR) protein, respectively. High resistance is very uncommon in Asian cultivated rice (Oryza sativa), with only two highly resistant accessions identified so far, but it is more frequent in African cultivated rice (Oryza glaberrima).

RESULTS

Here we report the findings of a resistance survey in a reference collection of 268 O. glaberrima accessions. A total of 40 resistant accessions were found, thus confirming the high frequency of resistance to RYMV in this species. We analysed the variability of resistance genes or candidate genes in this collection based on high-depth Illumina data or Sanger sequencing. Alleles previously shown to be associated with resistance were observed in 31 resistant accessions but not in any susceptible ones. Five original alleles with a frameshift or untimely stop codon in the candidate gene for RYMV2 were also identified in resistant accessions. A genetic analysis revealed that these alleles, as well as T-DNA insertions in the candidate gene, were responsible of RYMV resistance. All 40 resistant accessions were ultimately linked to a validated or candidate resistance allele at one of the three resistance genes to RYMV.

CONCLUSION

This study demonstrated that the RYMV2 resistance gene is homologous to the Arabidopsis CPR5 gene and revealed five new resistance alleles at this locus. It also confirmed the close association between resistance and an amino-acid substitution in the leucine-rich repeat of the NLR candidate for RYMV3. We also provide an extensive overview of the genetic diversity of resistance to RYMV in the O. glaberrima species, while underlining the contrasted pattern of diversity between O. glaberrima and O. sativa for this trait. The different resistance genes and alleles will be instrumental in breeding varieties with sustainable field resistance to RYMV.

HTLV-1 infection of myeloid cells: from transmission to immune alterations

Human T cell leukemia virus type 1 (HTLV-1), the etiological agent of adult T-cell leukemia/lymphoma (ATLL) and the demyelinating neuroinflammatory disease known as HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP), was the first human retrovirus to be discovered. T-cells, which represent the main reservoir for HTLV-1, have been the main focus of studies aimed at understanding viral transmission and disease progression. However, other cell types such as myeloid cells are also target of HTLV-1 infection and display functional alterations as a consequence. In this work, we review the current investigations that shed light on infection, transmission and functional alterations subsequent to HTLV-1 infection of the different myeloid cells types, and we highlight the lack of knowledge in this regard.

Age-related changes in regiospecific expression of Lipolysis Stimulated Receptor (LSR) in mice brain

The regulation of cholesterol, an essential brain lipid, ensures proper neuronal development and function, as demonstrated by links between perturbations of cholesterol metabolism and neurodegenerative diseases, including Alzheimer’s disease. The central nervous system (CNS) acquires cholesterol via de novo synthesis, where glial cells provide cholesterol to neurons. Both lipoproteins and lipoprotein receptors are key elements in this intercellular transport, where the latter recognize, bind and endocytose cholesterol containing glia-produced lipoproteins. CNS lipoprotein receptors are like those in the periphery, among which include the ApoB, E binding lipolysis stimulated lipoprotein receptor (LSR). LSR is a multimeric protein complex that has multiple isoforms including α and α’, which are seen as a doublet at 68 kDa, and β at 56 kDa. While complete inactivation of murine lsr gene is embryonic lethal, studies on lsr +/- mice revealed altered brain cholesterol distribution and cognitive functions. In the present study, LSR profiling in different CNS regions revealed regiospecific expression of LSR at both RNA and protein levels. At the RNA level, the hippocampus, hypothalamus, cerebellum, and olfactory bulb, all showed high levels of total lsr compared to whole brain tissues, whereas at the protein level, only the hypothalamus, olfactory bulb, and retina showed the highest levels of total LSR. Interestingly, major regional changes in LSR expression were observed in aged mice which suggests changes in cholesterol homeostasis in specific structures in the aging brain. Immunocytostaining of primary cultures of mature murine neurons and glial cells isolated from different CNS regions showed that LSR is expressed in both neurons and glial cells. However, lsr RNA expression in the cerebellum was predominantly higher in glial cells, which was confirmed by the immunocytostaining profile of cerebellar neurons and glia. Based on this observation, we would propose that LSR in glial cells may play a key role in glia-neuron cross talk, particularly in the feedback control of cholesterol synthesis to avoid cholesterol overload in neurons and to maintain proper functioning of the brain throughout life.

Response to early drought stress and identification of QTLs controlling biomass production under drought in pearl millet

Pearl millet plays a major role in food security in arid and semi-arid areas of Africa and India. However, it lags behind the other cereal crops in terms of genetic improvement. The recent sequencing of its genome opens the way to the use of modern genomic tools for breeding. Our study aimed at identifying genetic components involved in early drought stress tolerance as a first step toward the development of improved pearl millet varieties or hybrids. A panel of 188 inbred lines from West Africa was phenotyped under early drought stress and well-irrigated conditions. We found a strong impact of drought stress on yield components. This impact was variable between inbred lines. We then performed an association analysis with a total of 392,493 SNPs identified using Genotyping-by-Sequencing (GBS). Correcting for genetic relatedness, genome wide association study identified QTLs for biomass production in early drought stress conditions and for stay-green trait. In particular, genes involved in the sirohaem and wax biosynthesis pathways were found to co-locate with two of these QTLs. Our results might contribute to breed pearl millet lines with improved yield under drought stress.