Detection of aberrant DNA methylation patterns in sperm of male recurrent spontaneous abortion patients.

Aberrant DNA methylation patterns in sperm are a cause of embryonic failure and infertility, and could be a critical factor contributing to male recurrent spontaneous abortion (RSA). The purpose of this study was to reveal the potential effects of sperm DNA methylation levels in patients with male RSA. We compared sperm samples collected from fertile men and oligoasthenospermia patients. Differentially methylated sequences were identified by reduced representation bisulfite sequencing (RRBS) methods. The DNA methylation levels of the two groups were compared and qRT-PCR was used to validate the expression of genes showing differential methylation. The results indicated that no difference in base distribution was observed between the normal group and the patient group. However, the chromosome methylation in these two groups was markedly different. One site was located on chromosome 8 and measured 150 bp, while the other sites were on chromosomes 9, 10, and X and measured 135 bp, 68 bp, and 136 bp, respectively. In particular, two genes were found to be hypermethylated in these patients, one gene was DYDC2 (placed in the differential methylation region of chromosome 10), and the other gene was NXF3 (located on chromosome X). Expression levels of DYDC2 and NXF3 in the RSA group were significantly lower than those in the normal group (P < 0.05). Collectively, these results demonstrated that changes in DNA methylation might be related to male RSA. Our findings provide important information regarding the potential role of sperm DNA methylation in human development.

Effect of BMP-Wnt-Nodal signal on stem cell differentiation.

The generation of germ cells from embryonic stem cells in vitro has current historical significance. Western blot, qPCR, immunofluorescence and flow cytometry assays were used to investigate the differences in expression levels of totipotency and specific markers for Wnt regulation and the related signalling pathways during primordial germ cell-like cell (PGCLC) induction and differentiation. During PGCLC induction, activation of WNT3a increased the expression of NANOG, SOX2 and OCT4, but Mvh, DAZL, Blimp1, TFAP2C, Gata4, SOX17, EOMES, Brachyury and PRDM1 expression levels were significantly reduced. Inhibition of the WNT signal demonstrated the opposite effect. Similarly, inhibitors of BMP and the Nodal/Activin signal were used to determine the effect of signal pathways on differentiation. CER1 affected the Wnt signal and differentiation, but the inhibitor SB only regulated differentiation. BMP-WNT-NODAL were mainly responsible for regulating differentiation. Our results provide a reliable theoretical basis and feasibility for further clinical medical research.

Sex differences in the factors associated with sleep duration in university students: A cross-sectional study.

BACKGROUND: Insufficient sleep duration among university students was commonly associated with many detrimental effects. University students experience substantial environmental and psychological changes. Female and male university students may differ in many spheres. However, most research on sleep duration of university students is based on an aggregate sample rather than digging the sex-specific profiles. The objective of this study is to examine potential sex differences in the correlates of sleep duration and explore the underlying mechanism of correlations. METHODS: This is a large-scale university-based mental health survey, which was conducted in university students in Qinghai Province in Northwest China in December 2019. A multi-stage logistic regression was separately fitted by sex to examine the factors associated with short sleep duration in university students. RESULTS: A total of 5,552 university students with an average sleep duration of 6.88 h (SD = 1.04) were included, among which 35.0% of the participants may currently be sleeping less than the optimal duration. Female students (6.84 h, SD = 1.00) slept shorter than males (6.94 h, SD = 1.09). The only parallel between sexes was that both female and male students with 3-5 times weekly breakfast were less likely to have short sleep duration. Adjusting for depressive symptoms in the following step eliminated the association between anxiety symptoms and short sleep duration in the model for female students. Female-specific associated factors with short sleep duration were age, grade, academic pressure, weekly physical exercise, depressive symptoms. Male-specific characteristics were current smoking tobacco cigarette, self-perceived health, duration of daily Internet use. CONCLUSION: Characteristic profiles of sleep duration differed between female and male university students; only a few male-specific factors were identified. Psychological guidance and education courses as well as other interventions to improve university students' sleep and related health should be designed and implemented based on sex differences.

Childhood trauma and suicidal ideation among Chinese university students: the mediating effect of Internet addiction and school bullying victimisation.

AIMS: The factors associated with suicidal ideation among adolescents have been extensively characterised, but the mechanisms underlying the complexities of the relationship between experiences of childhood trauma and suicidal ideation have been less studied. This study examined the direct effect of childhood trauma on suicidal ideation on the one hand and whether school bullying victimisation and Internet addiction mediate the association between childhood trauma and suicidal ideation on the other hand. METHODS: This school-based mental health survey was carried out in Qinghai Province in Northwest China in December 2019. We employed standardised questionnaires to collect sociodemographic and target mental health outcomes. Hierarchical multiple logistic regression and structural equation modelling were performed for the data analyses. RESULTS: This study included 5864 university students. The prevalence of lifetime suicidal ideation and Internet addiction were 34.7% and 21.4%, respectively. Overall, 16.4% and 11.4% of participants reported experiences of childhood trauma and school bullying victimisation, respectively. There were direct effects of childhood trauma, school bullying victimisation and Internet addiction on suicidal ideation. The total effect of childhood trauma on suicidal ideation was 0.201 (p < 0.001). School bullying victimisation and Internet addiction mediated the relationship between childhood trauma and suicidal ideation. Internet addiction played a mediating role between school bullying and suicidal ideation. CONCLUSIONS: Childhood trauma had both direct and indirect effects on suicidal ideation; these effects were mediated by school bullying victimisation and Internet addiction in Chinese university students. Elucidating these relationships will therefore be useful in developing and implementing more targeted interventions and strategies to improve the mental well-being of Chinese university students.

MiR-140 targets RAP2A to enable the proliferation of insulin-treated ovarian granulosa cells.

BACKGROUND: We elucidated the role of specific MicroRNAs (miRNAs) in the development of polycystic ovary syndrome (PCOS) and explained the changes in the proliferation of granulosa cells. Excised ovarian cortex specimens were collected for miRNA profiling analysis (n = 20 PCOS females and 5 non-PCOS females). Insulin-treated ovarian granulosa cells isolated from mice were used for mechanical studies. RESULTS: High miR-140 expression was observed in PCOS samples and insulin-treated granulosa cells compared to that in non-PCOS and unstimulated cells, respectively. However, the Ras-related protein Rap-2a precursor (RAP2A) was downregulated in in PCOS. MTT assay and EdU staining showed that an miR-140 inhibitor attenuated viability in insulin-treated granulosa cells; cell viability increased with miR-140 overexpression. Reduced expression of miR-140 and the expression of the miR-140 mimic resulted in marked cell apoptosis, as evidenced by the results of PI flow cytometry and Annexin V-FITC; miR-140 overexpression results in downregulated RAP2A expression, and the miR-140 mimic directly bound to the RAP2A 3'-UTR, causing increase in RAP2A levels in insulin-treated granulosa cells; RNA-mediated silencing of RAP2A in insulin-treated granulosa cells restored cell proliferation and apoptosis to normal levels. Phosphorylated AKT was found to be negatively regulated through cross-talk between miR-140 and RAP2A. CONCLUSIONS: In conclusion, PCOS ovarian cortex specimens and insulin-treated granulosa cells showed elevated expression of miR-140, which could lead to increased proliferation and reduced apoptosis of cells by targeting RAP2A. This study may pave the way for future research on the properties of granulosa cells in PCOS.

Establishment of a feeder and serum-free culture system for human embryonic stem cells.

Stem cells are an immortal cell population capable of self-renewal; they are essential for human development and ageing and are a major focus of research in regenerative medicine. Despite considerable progress in differentiation of stem cells in vitro, culture conditions require further optimization to maximize the potential for multicellular differentiation during expansion. The aim of this study was to develop a feeder-free, serum-free culture method for human embryonic stem cells (hESCs), to establish optimal conditions for hESC proliferation, and to determine the biological characteristics of the resulting hESCs. The H9 hESC line was cultured using a homemade serum-free, feeder-free culture system, and growth was observed. The expression of pluripotency proteins (OCT4, NANOG, SOX2, LIN28, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81) in hESCs was determined by immunofluorescence and western blotting. The mRNA expression levels of genes encoding nestin, brachyury and α-fetoprotein in differentiated H9 cells were determined by RT-PCR. The newly developed culture system resulted in classical hESC colonies that were round or elliptical in shape, with clear and neat boundaries. The expression of pluripotency proteins was increased, and the genes encoding nestin, brachyury, and α-fetoprotein were expressed in H9 cells, suggesting that the cells maintained in vitro differentiation capacity. Our culture system containing a unique set of components, with animal-derived substances, maintained the self-renewal potential and pluripotency of H9 cells for eight passages. Further optimization of this system may expand the clinical application of hESCs.

Comparison of Sleep Disturbances Between Older Nursing Home Residents in High- and Low-Altitude Areas.

BACKGROUND AND OBJECTIVE: This study compared sleep disturbances between older adults living in nursing home located in high- and low-altitude areas and explored the association between sleep disturbances and quality of life (QoL). METHOD: In total, 207 participants living in a high-altitude area and 437 participants in a low-altitude area were included. Sleep disturbances (ie, difficulty in initiating sleep, difficulty in maintaining sleep, and early morning awakening) were measured using standardized questions. The independent demographic and clinical correlates of sleep disturbances in high-altitude area were examined using multiple logistic regression analyses. Each type of sleep disturbance was entered as the dependent variable separately, while those with significant group differences in the univariate analyses (ie, male gender, married status, age and depressive symptoms) were entered as independent variables. RESULTS: The prevalence of any type of sleep disturbances in the whole sample was 26.09%, with 41.54% in the high-altitude area and 18.76% in the low-altitude area. Physical, psychological, social, and environmental QoL domains were negatively associated with sleep disturbances in high-altitude area. Multiple logistic regression analyses revealed that male gender and married status were less likely to have sleep disturbances, while those with more severe depressive symptoms were more likely to have sleep disturbances in high-altitude area. CONCLUSION: Sleep disturbance is common among older nursing home residents in high-altitude areas. Considering the negative impact of sleep disturbance on QoL, regular screening and treatment strategies need to be developed directly for this population.