Translational offsetting as a mode of estrogen receptor α-dependent regulation of gene expression

Estrogen receptor alpha (ERα) activity is associated with increased cancer cell proliferation. Studies aiming to understand the impact of ERα on cancer-associated phenotypes have largely been limited to its transcriptional activity. Herein, we demonstrate that ERα coordinates its transcriptional output with selective modulation of mRNA translation. Importantly, translational perturbations caused by depletion of ERα largely manifest as "translational offsetting" of the transcriptome, whereby amounts of translated mRNAs and corresponding protein levels are maintained constant despite changes in mRNA abundance. Transcripts whose levels, but not polysome association, are reduced following ERα depletion lack features which limit translation efficiency including structured 5'UTRs and miRNA target sites. In contrast, mRNAs induced upon ERα depletion whose polysome association remains unaltered are enriched in codons requiring U34-modified tRNAs for efficient decoding. Consistently, ERα regulates levels of U34-modifying enzymes and thereby controls levels of U34-modified tRNAs. These findings unravel a hitherto unprecedented mechanism of ERα-dependent orchestration of transcriptional and translational programs that may be a pervasive mechanism of proteome maintenance in hormone-dependent cancers.

Fxr1 regulates sleep and synaptic homeostasis

The fragile X autosomal homolog 1 (Fxr1) is regulated by lithium and has been GWAS-associated with schizophrenia and insomnia. Homeostatic regulation of synaptic strength is essential for the maintenance of brain functions and involves both cell-autonomous and system-level processes such as sleep. We examined the contribution of Fxr1 to cell-autonomous homeostatic synaptic scaling and neuronal responses to sleep loss, using a combination of gene overexpression and Crispr/Cas9-mediated somatic knockouts to modulate gene expression. Our findings indicate that Fxr1 is downregulated during both scaling and sleep deprivation via a glycogen synthase kinase 3 beta (GSK3β)-dependent mechanism. In both conditions, downregulation of Fxr1 is essential for the homeostatic modulation of surface AMPA receptors and synaptic strength. Preventing the downregulation of Fxr1 during sleep deprivation results in altered EEG signatures. Furthermore, sequencing of neuronal translatomes revealed the contribution of Fxr1 to changes induced by sleep deprivation. These findings uncover a role of Fxr1 as a shared signaling hub between cell-autonomous homeostatic plasticity and system-level responses to sleep loss, with potential implications for neuropsychiatric illnesses and treatments.

Untargeted metabolomics identifies metabolic dysregulation of sphingolipids associated with aggressive chronic lymphocytic leukaemia and poor survival

BACKGROUND

Metabolic dependencies of chronic lymphocytic leukaemia (CLL) cells may represent new personalized treatment approaches in patients harbouring unfavourable features.

METHODS

Here, we used untargeted metabolomics and lipidomics analyses to isolate metabolomic features associated with aggressive CLL and poor survival outcomes. We initially focused on profiles associated with overexpression of the adverse metabolic marker glycosyltransferase (UGT2B17) associated with poor survival and drug resistance.

RESULTS

Leukaemic B-cell metabolomes indicated a significant perturbation in lipids, predominantly bio-active sphingolipids. Expression of numerous enzyme-encoding genes of sphingolipid biosynthesis pathways was significantly associated with shorter patient survival. Targeted metabolomics further exposed higher circulating levels of glucosylceramides (C16:0 GluCer) in CLL patients relative to healthy donors and an aggressive cancer biology. In multivariate analyses, C16:0 GluCer and sphinganine were independent prognostic markers and were inversely linked to treatment-free survival. These two sphingolipid species function as antagonistic mediators, with sphinganine being pro-apoptotic and GluCer being pro-proliferative, tested in leukemic B-CLL cell models. Blocking GluCer synthesis using ceramide glucosyltransferase inhibitors induced cell death and reduced the proliferative phenotype, which further sensitized a leukaemic B-cell model to the anti-leukaemics fludarabine and ibrutinib in vitro.

CONCLUSIONS

Specific sphingolipids may serve as prognostic markers in CLL, and inhibiting enzymatic pathways involved in their biosynthesis has potential as a therapaeutic approach.

Shifting focus: Time to look beyond the classic physiological adaptations associated with human heat acclimation

Planet Earth is warming at an unprecedented rate and our future is now assured to be shaped by the consequences of more frequent hot days and extreme heat. Humans will need to adapt both behaviorally and physiologically to thrive in a hotter climate. From a physiological perspective, countless studies have shown that human heat acclimation increases thermoeffector output (i.e., sweating and skin blood flow) and lowers cardiovascular strain (i.e., heart rate) during heat stress. However, the mechanisms mediating these adaptations remain understudied. Furthermore, several possible benefits of heat acclimation for other systems and functions involved in maintaining health and performance during heat stress remain to be elucidated. This review summarizes recent advances in human heat acclimation, with emphasis on recent studies that (1) advanced our understanding of the mechanisms mediating improved thermoeffector output and (2) investigated adaptations that go beyond those classically associated with heat acclimation. We highlight that these studies have contributed to a better understanding of the integrated physiological responses underlying human heat acclimation while leaving key unanswered questions that will need to be addressed in the future.

A longitudinal study of adolescent pathways differentiating suicide ideation and attempt in early adulthood

OBJECTIVE

Suicide ideation and attempt are leading risk factors for mortality in young adults. However, the adolescent risk factors distinguishing suicide ideation from attempt in young adults remain unclear. The present study aimed to examine the extent to which within-person stability and change in depressive symptoms, school difficulties, and peer victimization from ages 12 to 17 were differentially associated with later suicide ideation and attempt from ages 20 to 23.

METHOD

The study included 1647 participants from the Quebec Longitudinal Study of Child Development (QLSCD; 52% female). Participants reported on their depressive symptoms, school difficulties, and peer victimization at ages 12, 13, 15, and 17, and on suicide ideation and attempt at ages 20 and 23. Data were collected in the Province of Quebec, Canada, between 2010 and 2021.

RESULTS

Results indicated that 11% (N = 121) and 8% (N = 86) reported suicide ideation and attempt, respectively, between ages 20 and 23. A random-intercept cross-lagged panel model showed that within-person increases in depressive symptoms during adolescence were related to both suicide ideation and attempt, whereas within-person increases in school difficulties and peer victimization were for the most part related to suicide attempt only. Within-person stability in depressive symptoms from ages 12 to 17 years were also related to suicide attempt, and not ideation. However, this association was only marginally significant.

CONCLUSION

Findings suggest that experiencing unusual rises in school difficulties and peer victimization during adolescence, as well as depressive symptoms persisting over time, may distinguish young adults who think about suicide from those who attempt suicide.

Racial and ethnic differences in white matter hypointensities: The role of vascular risk factors

INTRODUCTION

White matter hypointensities (WMHs) are markers of cerebrovascular pathology associated with cognitive decline. Reports of racial and ethnic differences in WMHs have been inconsistent across studies. This study examined whether race and ethnicity influence WMH burden and whether vascular risk factors explain these differences.

METHODS

Data from the National Alzheimer's Coordinating Center included 7132 Whites, 892 Blacks, 283 Asians, and 661 Hispanics. Baseline and longitudinal WMHs were examined using linear regression and mixed-effects models across racial and ethnic groups, controlling for demographics and vascular risk factors.

RESULTS

Adjusting for vascular risk factors reduced WMH burden differences and eliminated differences in temporal regions in Black versus White older adults. For Hispanics, differences became significant after adjusting for vascular risk factors.

DISCUSSION

Although some racial and ethnic WMH disparities are influenced by vascular risk factors, others persist, highlighting the need for multidimensional approaches when targeting WMHs in diverse populations.

HIGHLIGHTS

Current research is inconsistent as to whether there are racial differences in white matter hypointensities (WMHs). Blacks exhibit higher WMH burden than Whites, mediated by vascular factors. In Hispanics, WMH differences emerged only after adjusting for vascular risk factors.

When Eating Intuitively Is Not Always a Positive Response: Using Machine Learning to Better Unravel Eaters Profiles

BACKGROUND

The aim of the present study was to identify eaters profiles using the latest advantages of Machine Learning approach to cluster analysis.

METHODS

A total of 317 participants completed an online-based survey including self-reported measures of body image dissatisfaction, bulimia, restraint, and intuitive eating. Analyses were conducted in two steps: (a) identifying an optimal number of clusters, and (b) validating the clustering model of eaters profile using a procedure inspired by the Causal Reasoning approach.

RESULTS

This study reveals a 7-cluster model of eaters profiles. The characteristics, needs, and strengths of each eater profile are discussed along with the presentation of a continuum of eaters profiles.

CONCLUSIONS

This conceptualization of eaters profiles could guide the direction of health education and treatment interventions targeting perceptual and eating dimensions.