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16 result(s) for "Maladies neurodéveloppementales et neurovasculaires (NeuroDiderot (UMR_S_1141 / U1141))"
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Essential omega-3 fatty acids tune microglial phagocytosis of synaptic elements in the mouse developing brain
Omega-3 fatty acids (n-3 PUFAs) are essential for the functional maturation of the brain. Westernization of dietary habits in both developed and developing countries is accompanied by a progressive reduction in dietary intake of n-3 PUFAs. Low maternal intake of n-3 PUFAs has been linked to neurodevelopmental diseases in Humans. However, the n-3 PUFAs deficiency-mediated mechanisms affecting the development of the central nervous system are poorly understood. Active microglial engulfment of synapses regulates brain development. Impaired synaptic pruning is associated with several neurodevelopmental disorders. Here, we identify a molecular mechanism for detrimental effects of low maternal n-3 PUFA intake on hippocampal development in mice. Our results show that maternal dietary n-3 PUFA deficiency increases microglia-mediated phagocytosis of synaptic elements in the rodent developing hippocampus, partly through the activation of 12/15-lipoxygenase (LOX)/ 12-HETE signaling, altering neuronal morphology and affecting cognitive performance of the offspring. These findings provide a mechanistic insight into neurodevelopmental defects caused by maternal n-3 PUFAs dietary deficiency.
A cell fate decision map reveals abundant direct neurogenesis bypassing intermediate progenitors in the human developing neocortex
Abstract The human neocortex has undergone strong evolutionary expansion, largely due to an increased progenitor population, the basal radial glial cells. These cells are responsible for the production of a diversity of cell types, but the successive cell fate decisions taken by individual progenitors remain unknown. Here we developed a semi-automated live/fixed correlative imaging method to map basal radial glial cell division modes in early fetal tissue and cerebral organoids. Through the live analysis of hundreds of dividing progenitors, we show that basal radial glial cells undergo abundant symmetric amplifying divisions, and frequent self-consuming direct neurogenic divisions, bypassing intermediate progenitors. These direct neurogenic divisions are more abundant in the upper part of the subventricular zone. We furthermore demonstrate asymmetric Notch activation in the self-renewing daughter cells, independently of basal fibre inheritance. Our results reveal a remarkable conservation of fate decisions in cerebral organoids, supporting their value as models of early human neurogenesis.
Targeting ERK-MYD88 interaction leads to ERK dysregulation and immunogenic cancer cell death
The quest for targeted therapies is critical in the battle against cancer. The RAS/MAP kinase pathway is frequently implicated in neoplasia, with ERK playing a crucial role as the most distal kinase in the RAS signaling cascade. Our previous research demonstrated that the interaction between ERK and MYD88, an adaptor protein in innate immunity, is crucial for RAS-dependent transformation and cancer cell survival. In this study, we examine the biological consequences of disrupting the ERK-MYD88 interaction through the ERK D-recruitment site (DRS), while preserving ERK’s kinase activity. Our results indicate that EI-52, a small-molecule benzimidazole targeting ERK-MYD88 interaction induces an HRI-mediated integrated stress response (ISR), resulting in immunogenic apoptosis specific to cancer cells. Additionally, EI-52 exhibits anti-tumor efficacy in patient-derived tumors and induces an anti-tumor T cell response in mice in vivo. These findings suggest that inhibiting the ERK-MYD88 interaction may be a promising therapeutic approach in cancer treatment.
How to perform prespecified subgroup analyses when using propensity score methods in the case of imbalanced subgroups
Background Looking for treatment-by-subset interaction on a right-censored outcome based on observational data using propensity-score (PS) modeling is of interest. However, there are still issues regarding its implementation, notably when the subsets are very imbalanced in terms of prognostic features and treatment prevalence. Methods We conducted a simulation study to compare two main PS estimation strategies, performed either once on the whole sample (“across subset”) or in each subset separately (“within subsets”). Several PS models and estimands are also investigated. We then illustrated those approaches on the motivating example, namely, evaluating the benefits of facial nerve resection in patients with parotid cancer in contact with the nerve, according to pretreatment facial palsy. Results Our simulation study demonstrated that both strategies provide close results in terms of bias and variance of the estimated treatment effect, with a slight advantage for the “across subsets” strategy in very small samples, provided that interaction terms between the subset variable and other covariates influencing the choice of treatment are incorporated. PS matching without replacement resulted in biased estimates and should be avoided in the case of very imbalanced subsets. Conclusions When assessing heterogeneity in the treatment effect in small samples, the “across subsets” strategy of PS estimation is preferred. Then, either a PS matching with replacement or a weighting method must be used to estimate the average treatment effect in the treated or in the overlap population. In contrast, PS matching without replacement should be avoided in this setting.
Monocytopenia, monocyte morphological anomalies and hyperinflammation characterise severe COVID ‐19 in type 2 diabetes
Early in the COVID-19 pandemic, type 2 diabetes (T2D) was marked as a risk factor for severe disease and mortality. Inflammation is central to the aetiology of both conditions where variations in immune responses can mitigate or aggravate disease course. Identifying at-risk groups based on immunoinflammatory signatures is valuable in directing personalised care and developing potential targets for precision therapy. This observational study charac-terised immunophenotypic variation associated with COVID-19 severity in T2D. Broad-spectrum immunophenotyping quantified 15 leucocyte populations in peripheral circulation from a cohort of 45 hospitalised COVID-19 patients with and without T2D. Lympho-cytopenia and specific loss of cytotoxic CD8 + lymphocytes were associated with severe COVID-19 and requirement for intensive care in both non-diabetic and T2D patients. A morphological anomaly of increased monocyte size and monocytopenia restricted to classical CD14 Hi CD16 À monocytes was specifically associated with severe COVID-19 in patients with T2D requiring intensive care. Increased expression of inflammatory markers reminiscent of the type 1 interferon pathway (IL6, IL8, CCL2, INFB1) underlaid the immunophenotype associated with T2D. These immunophenotypic and hyperinflammatory changes may contribute to increased voracity of COVID-19 in T2D. These findings allow precise identification of T2D patients with severe COVID-19 as well as provide evidence that the type 1 interferon pathway may be an actionable therapeutic target for future studies.
Prenatal treatment with preimplantation factor improves early postnatal neurogenesis and cognitive impairments in a mouse model of Down syndrome
Down syndrome (DS) is a genetic disease characterized by a supernumerary chromosome 21. Intellectual deficiency (ID) is one of the most prominent features of DS. Central nervous system defects lead to learning disabilities, motor and language delays, and memory impairments. At present, a prenatal treatment for the ID in DS is lacking. Subcutaneous administration of synthetic preimplantation factor (sPIF, a peptide with a range of biological functions) in a model of severe brain damage has shown neuroprotective and anti-inflammatory properties by directly targeting neurons and microglia. Here, we evaluated the effect of PIF administration during gestation and until weaning on Dp(16)1Yey mice (a mouse model of DS). Possible effects at the juvenile stage were assessed using behavioral tests and molecular and histological analyses of the brain. To test the influence of perinatal sPIF treatment at the adult stage, hippocampus-dependent memory was evaluated on postnatal day 90. Dp(16)1Yey pups showed significant behavioral impairment, with impaired neurogenesis, microglial cell activation and a low microglial cell count, and the deregulated expression of genes linked to neuroinflammation and cell cycle regulation. Treatment with sPIF restored early postnatal hippocampal neurogenesis, with beneficial effects on astrocytes, microglia, inflammation, and cell cycle markers. Moreover, treatment with sPIF restored the level of DYRK1A, a protein that is involved in cognitive impairments in DS. In line with the beneficial effects on neurogenesis, perinatal treatment with sPIF was associated with an improvement in working memory in adult Dp(16)1Yey mice. Perinatal treatment with sPIF might be an option for mitigating cognitive impairments in people with DS.
Cerebral injuries in neonatal encephalopathy treated with hypothermia: French LyTONEPAL cohort
BackgroundHypothermia is widely used for infants with hypoxic–ischemic neonatal encephalopathy but its impact remains poorly described at a population level. We aimed to describe brain imaging in infants born at ≥36 weeks’ gestation, with moderate/severe encephalopathy treated with hypothermia.MethodsDescriptive analysis of brain MRI and discharge neurological examination for infants included in the French national multicentric prospective observational cohort LyTONEPAL.ResultsAmong 575 eligible infants, 479 (83.3%) with MRI before 12 days of life were included. MRI was normal for 48.2% (95% CI 43.7–52.8). Among infants with brain injuries, 62.5% (95% CI 56.2–68.5) had damage to more than one structure, 19.8% (95% CI 15.0–25.3) showed a pattern-associating injuries of basal ganglia/thalami (BGT), white matter (WM) and cortex. Overall, 68.4% (95% CI 62.0–74.3) of infants with normal MRI survived with a normal neurological examination. The rate of death was 15.4% (95% CI 12.3–19.0), predominantly for infants with the combined BGT, cortex, and/or WM injuries.ConclusionsAmong infants with neonatal encephalopathy treated with hypothermia, two-thirds of those with normal MRI survived with a normal neurological examination at discharge. When present, brain injuries often involved more than one structure.Trial registrationThe trial was registered at ClinicalTrials.gov (NCT02676063).ImpactIn this multicentric cohort of infants with neonatal encephalopathy (LYTONEPAL) two-thirds survived with normal MRI and neurological examination at discharge.In total, 10% of newborns showed a pattern associating injuries of the basal ganglia—thalami, white matter, and cortex, which was correlated with a high risk of death at discharge.The evolution of MRI techniques and sequences in the era of hypothermia calls for a revisiting of imaging protocol in neonatal encephalopathy, especially for the timing.The neurological examination did not give evidence of brain injuries, thus questioning the reproducibility of the clinical exam or the neonatal brain functionality.
Mortality and neurodevelopmental outcomes at 2 years’ corrected age of very preterm infants with necrotising enterocolitis or spontaneous intestinal perforation: The EPIPAGE-2 cohort study
Purpose: The primary objective was to evaluate the impact of necrotising enterocolitis (NEC) and spontaneous intestinal perforation (SIP) on mortality and neurodevelopmental outcomes at 2 years' corrected age (CA) in infants born before 32 weeks' gestation (WG). Methods: We studied neurodevelopment at 2 years' CA of infants with NEC or SIP who were born before 32 WG from the EPIPAGE-2 cohort study. The primary outcome was death or the presence of moderate-to-severe motor or sensory disability defined by moderate-to-severe cerebral palsy or hearing or visual disability. The secondary outcome was developmental delay defined by a score < 2 SDs below the mean for any of the five domains of the Ages and Stages Questionnaire.Results: At 2 years' CA, 46% of infants with SIP, 34% of infants with NEC, and 14% of control infants died or had a moderate-to-severe sensorimotor disability (p < 0.01). This difference was mainly due to an increase in in-hospital mortality in the infants with SIP or NEC. Developmental delay at 2 years' CA was more frequent for infants with SIP than controls (70.8% vs 44.0%, p = 0.02) but was similar for infants with NEC and controls (49.3% vs 44.0%, p = 0.5). On multivariate analysis, the likelihood of developmental delay was associated with SIP (adjusted odds ratio = 3.0, 95% CI 1.0-9.1) but not NEC as compared with controls.Conclusion: NEC and SIP significantly increased the risk of death or sensorimotor disability at 2 years' CA. SIP was also associated with risk of developmental delay at 2 years' CA.
Perinatal mortality and morbidity, timing and route of delivery in monoamniotic twin pregnancies: a retrospective cohort study
Purpose Monoamniotic twin pregnancies are at high risk of perinatal complications and fetal loss. The objective of this study is to describe the management and outcomes of monoamniotic twin pregnancies in a French university obstetrics department. Methods Retrospective review of all consecutive monoamniotic twin pregnancies managed between 1992 and 2018 in a level-3 university hospital maternity unit. Antenatal variables, gestational age and other neonatal characteristics at delivery, mode of delivery, and its reason were recorded, together with outcomes, including a composite adverse neonatal outcome. Results Overall, 46 monoamniotic twin pregnancies (92 fetuses) were identified during the study period. Among them, 27 fetal losses and 2 early neonatal deaths were reported. Congenital abnormalities accounted for 33.3% of the 27 fetal losses, and unexpected fetal deaths for 29.6%. Among the 37 women who gave birth to 65 live infants at 23 or more weeks of gestation, 17 had cesarean and 19 vaginal deliveries. Overall and composite adverse neonatal outcomes did not differ significantly for the 33 children born vaginally and the 31 by cesarean deliveries. The prospective risk of intrauterine death in all 92 fetuses reached its nadir of 1.8% at 33(6/7) weeks. Conclusion This series confirms the still high risk of fetal and neonatal death of these twins and shows that congenital abnormalities but also unexpected fetal deaths account for the majority of pre- and postnatal mortality. Our data suggest that vaginal delivery of monoamniotic twins is safe and that delivery for uncomplicated monoamniotic twins should be considered around 33 weeks of gestation, but not later than 35 weeks.
Does pre-testing promote better retention than post-testing?
Compared with other learning strategies, retrieval practice seems to promote superior long-term retention. This has been found mostly in conditions where learners take tests after being exposed to learning content. However, a pre-testing effect has also been demonstrated, with promising results. This raises the question, for a given amount of time dedicated to retrieval practice, whether learners should be tested before or after an initial exposure to learning content. Our experiment directly compares the benefits of post-testing and pre-testing relative to an extended reading condition, on a retention test 7 days later. We replicated both post-testing (d = 0.74) and pre-testing effects (d = 0.35), with significantly better retention in the former condition. Post-testing also promoted knowledge transfer to previously untested questions, whereas pre-testing did not. Our results thus suggest that it may be more fruitful to test students after than before exposure to learning content.