Circadian gene Rev-erbα influenced by sleep conduces to pregnancy by promoting endometrial decidualization via IL-6-PR-C/EBPβ axis

Preconception sleep, pregnancy loss, and adverse pregnancy outcomes among women with a history of pregnancy loss

STUDY QUESTION

Are preconception sleep characteristics associated with pregnancy loss and adverse pregnancy outcomes?

SUMMARY ANSWER

Preconception sleep characteristics were not associated with pregnancy loss, but earlier sleep midpoints were associated with lower risk of adverse pregnancy outcomes, while social jetlag >1 h was associated with greater risk of a composite of adverse pregnancy outcomes.

WHAT IS KNOWN ALREADY

Short sleep duration in mid-pregnancy has been associated with risk of second-trimester pregnancy loss, preterm birth (PTB), and hypertensive disorders of pregnancy (HDP). The relationships between preconception sleep and pregnancy loss, and adverse pregnancy outcomes have not been well characterized, despite plausible links.

STUDY DESIGN, SIZE, DURATION

This was a secondary analysis of a randomized controlled trial conducted between 2006 and 2012 that prospectively followed 1228 women who were attempting to become pregnant after a history of pregnancy loss. Women were followed for ≤6 cycles while attempting pregnancy, and throughout pregnancy if they conceived. Over the follow-up, 140 women withdrew from the study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study evaluated baseline, self-reported preconception sleep duration, sleep latency, sleep midpoint, and social jetlag with risk of pregnancy loss and adverse pregnancy outcomes (e.g. PTB, HDP, and gestational diabetes (GDM)) among 1228 women with a history of pregnancy loss in the EAGeR trial. Pregnancy was documented by hCG tests; 797 women became pregnant over the follow-up. Pregnancy losses were defined as any loss after a positive hCG test; there were 188 pregnancy losses. PTB, HDP, and GDM cases were ascertained via medical record abstraction. PTB (n = 53), HDP (n = 62), and GDM (n = 22) were examined as a composite outcome (n = 118) and PTB and HDP were examined individually in exploratory analyses. GDM was not examined individually due to insufficient numbers. Log-Poisson models were used to estimate relative risks (RR) and 95% CIs for associations between preconception sleep characteristics, and pregnancy loss or adverse pregnancy outcomes with adjustment for age, BMI, lifestyle, and sociodemographic factors. Stabilized inverse probability weights were applied to address potential selection bias from loss to follow-up and from restricting to pregnancy.

MAIN RESULTS AND THE ROLE OF CHANCE

Preconception sleep characteristics were not associated with risk of pregnancy loss. Preconception sleep duration and sleep latency were not associated with risk of the composite adverse pregnancy outcome. Early preconception sleep midpoints were associated with a lower risk of the composite adverse pregnancy outcome (first vs second tertile RR; 0.63, 95% CI: 0.40, 0.98) and preconception social jetlag was associated with a higher risk of the composite adverse pregnancy outcome (>1 vs ≤1 h RR; 1.65, 95% CI: 1.11, 2.44).

LIMITATIONS, REASONS FOR CAUTION

Preconception sleep was restricted to baseline self-report, which may be non-differentially misclassified and may underestimate these associations. The EAGeR study did not measure sleep during pregnancy. There were few adverse pregnancy outcomes and thus limited power to evaluate individual outcomes; the findings could be due to chance.

WIDER IMPLICATIONS OF THE FINDINGS

These findings suggest that preconception sleep is not associated with pregnancy loss, but preconception sleep timing may be relevant for risk of adverse pregnancy outcomes. Additional studies on preconception sleep and adverse pregnancy outcomes are needed given the potential impact of poor sleep on pregnancy outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

Joshua R. Freeman and this work were supported by the Intramural Research Program Cancer Research Training Award, National Cancer Institute, National Institutes of Health (ZIA CP010197), and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland (Contract numbers: HHSN267200603423, HHSN267200603424, HHSN267200603426, HHSN275201300023I). Dr Silver received NIH funding through the listed contracts as site-PI for the original EAGeR trial at the University of Utah. Dr O'Brien reports receiving funding from the Star Legacy Foundation (paid to institution); an advisory board role at the Star Legacy Foundation; and receiving travel support from the Star Legacy Foundation. Dr Dunietz reports a role as Associate Editor at Human Reproduction and a role on the Journal Editorial Board of SLEEP. Dr Purdue-Smithe is an employee of Merck & Co. and has received stock compensation as an employee of Merck & Co. in the past 36 months. The work in this manuscript was completed before Dr Purdue-Smithe's employment at Merck & Co. and is unrelated to Dr Purdue-Smithe's work at the company. Dr Silver reports royalties or licenses from BJOG and UpToDate, Inc. in the past 36 months, receiving payment or honoraria for Grand Rounds in the past 36 months, and participating on a Data Safety Monitoring Board or Advisory Board for a National Institutes of Health-funded Apple Trial in the past 36 months. The other authors report there are no competing interests to declare.

TRIAL REGISTRATION NUMBER

Clinicaltrials.gov NCT00467363.

REV-ERBα Inhibits Osteoclastogenesis and Protects against Alveolar Bone Loss

Circadian rhythm disruption is thought to be associated with periodontitis, and molecular clock genes play critical roles in regulating bone homeostasis. However, the specific contribution of molecular clock genes to alveolar bone resorption caused by periodontitis is poorly understood. In this study, we introduced a novel Periodontitis Circadian Rhythm Score (PeriCRS) model that was established through machine learning using periodontal transcriptomic data from periodontitis clinical cohorts in the Gene Expression Omnibus (GEO) database. This approach revealed the potential regulatory role of circadian rhythm disruption in periodontitis and identified key molecular clock genes associated with alveolar bone destruction. Moreover, we established an experimental periodontitis model with circadian rhythm disturbance via periodontal ligation in mice exposed to a 6-h advanced LD12:12 cycle every 2 d. Our bioinformatics analysis revealed that NR1D1, which encodes REV-ERBα, is a pivotal factor in the impact of circadian rhythm disruption on periodontitis in periodontal tissues. Next, we confirmed the abnormal expression of the molecular clock gene Rev-erbα in inflammatory periodontal tissue in mice and confirmed that circadian rhythm disruption altered REV-ERBα expression. Furthermore, the activation of REV-ERBα with the agonist SR9009 notably decreased RANKL-induced osteoclast differentiation and suppressed the expression of osteoclast-related factors. Subsequent in vivo experiments demonstrated that SR9009 mitigated alveolar bone loss caused by periodontitis. Mechanistically, we found that the IL-22-STAT3 pathway inhibited REV-ERBα expression and modulated RANKL-induced osteoclast differentiation in vitro. Our results elucidate the role of REV-ERBα in osteoclastogenesis and suggest a potential new therapeutic avenue for addressing alveolar bone resorption associated with periodontitis.

Circadian Regulation of Lipid Metabolism during Pregnancy

A cluster of metabolic changes occur to provide energy for fetal growth and development during pregnancy. There is a burgeoning body of research highlighting the pivotal role of circadian rhythms in the pathogenesis of metabolic disorders and lipid homeostasis in mammals. Perturbations of the circadian system and lipid metabolism during gestation might be responsible for a variety of adverse reproductive outcomes comprising miscarriage, gestational diabetes mellitus, and preeclampsia. Growing studies have confirmed that resynchronizing circadian rhythms might alleviate metabolic disturbance. However, there is no clear evidence regarding the specific mechanisms by which the diurnal rhythm regulates lipid metabolism during pregnancy. In this review, we summarize previous knowledge on the strong interaction among the circadian clock, lipid metabolism, and pregnancy. Analyzing the circadian clock genes will improve our understanding of how circadian rhythms are implicated in complex lipid metabolic disorders during pregnancy. Exploring the potential of resynchronizing these circadian rhythms to disrupt abnormal lipid metabolism could also result in a breakthrough in reducing adverse pregnancy outcomes.

Sleep deprivation causes gut dysbiosis impacting on systemic metabolomics leading to premature ovarian insufficiency in adolescent mice

Rationale: Currently, there are occasional reports of health problems caused by sleep deprivation (SD). However, to date, there remains a lack of in-depth research regarding the effects of SD on the growth and development of oocytes in females. The present work aimed to investigate whether SD influences ovarian folliculogenesis in adolescent female mice. Methods: Using a dedicated device, SD conditions were established in 3-week old female mice (a critical stage of follicular development) for 6 weeks and gut microbiota and systemic metabolomics were analyzed. Analyses were related to parameters of folliculogenesis and reproductive performance of SD females. Results: We found that the gut microbiota and systemic metabolomics were severely altered in SD females and that these were associated with parameters of premature ovarian insufficiency (POI). These included increased granulosa cell apoptosis, reduced numbers of primordial follicles (PmFs), correlation with decreased AMH, E2, and increased LH in blood serum, and a parallel increased number of growing follicles and changes in protein expression compatible with PmF activation. SD also reduced oocyte maturation and reproductive performance. Notably, fecal microbial transplantation from SD females into normal females induced POI parameters in the latter while niacinamide (NAM) supplementation alleviated such symptoms in SD females. Conclusion: Gut microbiota and alterations in systemic metabolomics caused by SD induced POI features in juvenile females that could be counteracted with NAM supplementation.

Potential Role of Bmal1 in Lipopolysaccharide-Induced Depression-Like Behavior and its Associated "Inflammatory Storm"

Inflammation plays an important role in the pathogenesis of depression; however, the underlying mechanisms remain unclear. Apart from the disordered circadian rhythm in animal models and patients with depression, dysfunction of clock genes has been reported to be involved with the progress of inflammation. This study aimed to investigate the role of circadian clock genes, especially brain and muscle ARNT-like 1 (Bmal1), in the linkage between inflammation and depression. Lipopolysaccharide (LPS)-challenged rats and BV2 cells were used in the present study. Four intraperitoneal LPS injections of 0.5 mg/kg were administered once every other day to the rats, and BV2 cells were challenged with LPS for 24 h at the working concentration of 1 mg/L, with or without the suppression of Bmal1 via small interfering RNA. The results showed that LPS could successfully induce depression-like behaviors and an "inflammatory storm" in rats, as indicated by the increased immobility time in the forced swimming test and the decreased saccharin preference index in the saccharin preference test, together with hyperactivity of the hypothalamic-pituitary-adrenal axis, hyperactivation of astrocyte and microglia, and increased peripheral and central abundance of tumor necrosis factor-α, interleukin 6, and C-reactive protein. Moreover, the protein expression levels of brain-derived neurotrophic factor, triggering receptor expressed on myeloid cells 1, Copine6, and Synaptotagmin1 (Syt-1) decreased in the hippocampus and hypothalamus, whereas the expression of triggering receptor expressed on myeloid cells 2 increased. Interestingly, the fluctuation of temperature and serum concentration of melatonin and corticosterone was significantly different between the groups. Furthermore, protein expression levels of the circadian locomotor output cycles kaput, cryptochrome 2, and period 2 was significantly reduced in the hippocampus of LPS-challenged rats, whereas Bmal1 expression was significantly increased in the hippocampus but decreased in the hypothalamus, where it was co-located with neurons, microglia, and astrocytes. Consistently, apart from the reduced cell viability and increased phagocytic ability, LPS-challenged BV2 cells presented a similar trend with the changed protein expression in the hippocampus of the LPS model rats. However, the pathological changes in BV2 cells induced by LPS were reversed after the suppression of Bmal1. These results indicated that LPS could induce depression-like pathological changes, and the underlying mechanism might be partly associated with the imbalanced expression of Bmal1 and its regulated dysfunction of the circadian rhythm.

Molecular Mechanisms of the Melatonin Receptor Pathway Linking Circadian Rhythm to Type 2 Diabetes Mellitus

Night-shift work and sleep disorders are associated with type 2 diabetes (T2DM), and circadian rhythm disruption is intrinsically involved. Studies have identified several signaling pathways that separately link two melatonin receptors (MT1 and MT2) to insulin secretion and T2DM occurrence, but a comprehensive explanation of the molecular mechanism to elucidate the association between these receptors to T2DM, reasonably and precisely, has been lacking. This review thoroughly explicates the signaling system, which consists of four important pathways, linking melatonin receptors MT1 or MT2 to insulin secretion. Then, the association of the circadian rhythm with MTNR1B transcription is extensively expounded. Finally, a concrete molecular and evolutionary mechanism underlying the macroscopic association between the circadian rhythm and T2DM is established. This review provides new insights into the pathology, treatment, and prevention of T2DM.