Aneuploidy and cell cycle control in the mouse preimplantation embryo

Durant la division cellulaire, la ségrégation des chromosomes et le partage du cytoplasme sont essentiels pour maintenir l'intégrité génomique. Cependant, les erreurs de ségrégation sont fréquentes chez l'embryon préimplantatoire de mammifère et entraînent un gain ou une perte de chromosomes, appelé aneuploïdie. L'aneuploïdie est préjudiciable au développement et est la principale cause de pertes de grossesse. La mitose est coordonnée par cycle cellulaire, notamment la Cycline-B. Comprendre comment la destruction de la Cycline-B contrôle la sortie de la mitose des embryons pourrait expliquer pourquoi l'aneuploïdie est courante en clinique de fertilité. Nous avons étudié la destruction de la Cycline-B en fonction du stade de développement et de l'aneuploïdie. La littérature suggère que l’aneuploïdie perturbe le cycle cellulaire conduisant les cliniques de fertilité à utiliser la durée du cycle cellulaire et la morphologie (morphocinétique) pour prédire la santé de l'embryon. Cependant, la prédiction de la ploïdie par morphocinétique reste à démontrer. Notre objectif était de savoir comment l'aneuploïdie affecte le cycle cellulaire et le développement de l'embryon. Après une micro-injection de CyclineB1:GFP (Cycline-B) et H2B:RFP (chromosomes), les embryons de souris furent imagés par microscopie confocale. Des cellules aneuploïdes furent générées chimiquement pour évaluer leurs morphocinétiques. Curieusement, l'apparition de la Cycline-B après nuclear envelope breakdown a été devancée avec la progression du développement indépendamment de la taille des cellules. De plus, les erreurs de ségrégation ont peu impacté le développement et la destruction de la Cycline-B. Nous concluons que la morphocinétique est un outil prédictif peu fiable pour identifier les embryons aneuploïdes.During cell division, it is essential that chromosome segregation during mitosis, and the partitioning of the cytoplasm at cytokinesis occur in successive timing to maintain genomic integrity. However, segregation errors are frequently observed in the early mammalian embryo, causing daughter cells to inherit whole chromosome gains and losses, termed aneuploidy. Aneuploidy is detrimental to development, being the leading cause of pregnancy loss and developmental disorders. The timing of mitosis is coordinated by the cell cycle component, Cyclin B. Understanding how Cyclin B destruction temporally controls mitotic exit in embryos could help elucidate why aneuploidy is common in IVF clinics. We investigate how Cyclin B destruction changes in different developmental stages and the presence of aneuploidy. Literature suggests aneuploidy disrupts the cell cycle, leading IVF clinics to use cell cycle timings and morphology (morphokinetics) to predict embryo health. However, whether morphokinetics predicts embryo ploidy is uncertain. We seek to investigate how aneuploidy affects the cell cycle and embryo development. We used live-cell confocal imaging and microinjection of CyclinB1:GFP and H2B:RFP mRNA to visualise Cyclin B and chromosomes during mitosis in the 2-, 4- and 8-cell stage mouse embryo. Secondly, we pharmacologically-induced aneuploidy to assess aneuploid morphokinetics. Interestingly, we observe a developmental trend, independent of cell size, where Cyclin B onset begins progressively sooner after NEBD at the 2-, 4- and 8-cell stage. Additionally, chromosome segregation errors had little impact on Cyclin B destruction and development. Finally, we find morphokinetics to be a poor predictive tool in identifying aneuploid embryos

A primary effect of palmitic acid on mouse oocytes is the disruption of the structure of the endoplasmic reticulum

Exposure of mouse oocytes to saturated fatty acids (FAs) such as palmitic acid (PA) has been shown to increase lipid content and cause an endoplasmic reticulum (ER) stress response and changes in the mitochondrial redox state. PA can also disrupt Ca2+ stores in other cell types. The links between these intracellular changes, or whether they are prevented by mono-unsaturated FAs such as oleic acid (OA), is unclear. Here, we have investigated the effects of FAs on mouse oocytes, that are maturated in vitro, using coherent anti-Stokes Raman scattering and two-photon fluorescence microscopy. When oocytes were matured in the presence of PA, there were changes in the aggregation pattern and size of lipid droplets that were mitigated by co-incubation in OA. Maturation in PA alone also caused a distinctive disruption of the ER structure. This effect was prevented by incubation of OA with PA. In contrast, maturation of mouse oocytes in medium containing PA was not associated with any significant change in the redox state of mitochondria or the Ca2+ content of intracellular stores. These data suggest that a primary effect of saturated FAs such as PA on oocytes is to disrupt the structure of the ER and this is not due to an effect on the mitochondria or Ca2+ stores

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

Research Review: DSM-V conduct disorder: research needs for an evidence base

This article charts a strategic research course toward an empirical foundation for the diagnosis of conduct disorder in the forthcoming DSM-V. Since the DSM-IV appeared in 1994, an impressive amount of new information about conduct disorder has emerged. As a result of this new knowledge, reasonable rationales have been put forward for adding to the conduct disorder diagnostic protocol: a childhood-limited subtype, family psychiatric history, callous-unemotional traits, female-specific criteria, preschool-specific criteria, early substance use, and biomarkers from genetics, neuroimaging, and physiology research. This article reviews the evidence for these and other potential changes to the conduct disorder diagnosis. We report that although there is a great deal of exciting research into each of the topics, very little of it provides the precise sort of evidence base required to justify any alteration to the DSM-V. We outline specific research questions and study designs needed to build the lacking evidence base for or against proposed changes to DSM-V conduct disorder

Applying polygenic risk scoring for psychiatric disorders to a large family with bipolar disorder and major depressive disorder

Psychiatric disorders are thought to have a complex genetic pathology consisting of interplay of common and rare variation. Traditionally, pedigrees are used to shed light on the latter only, while here we discuss the application of polygenic risk scores to also highlight patterns of common genetic risk. We analyze polygenic risk scores for psychiatric disorders in a large pedigree (n similar to 260) in which 30% of family members suffer from major depressive disorder or bipolar disorder. Studying patterns of assortative mating and anticipation, it appears increased polygenic risk is contributed by affected individuals who married into the family, resulting in an increasing genetic risk over generations. This may explain the observation of anticipation in mood disorders, whereby onset is earlier and the severity increases over the generations of a family. Joint analyses of rare and common variation may be a powerful way to understand the familial genetics of psychiatric disorders

Applying polygenic risk scoring for psychiatric disorders to a large family with bipolar disorder and major depressive disorder

Psychiatric disorders are thought to have a complex genetic pathology consisting of interplay of common and rare variation. Traditionally, pedigrees are used to shed light on the latter only, while here we discuss the application of polygenic risk scores to also highlight patterns of common genetic risk. We analyze polygenic risk scores for psychiatric disorders in a large pedigree (n similar to 260) in which 30% of family members suffer from major depressive disorder or bipolar disorder. Studying patterns of assortative mating and anticipation, it appears increased polygenic risk is contributed by affected individuals who married into the family, resulting in an increasing genetic risk over generations. This may explain the observation of anticipation in mood disorders, whereby onset is earlier and the severity increases over the generations of a family. Joint analyses of rare and common variation may be a powerful way to understand the familial genetics of psychiatric disorders