Alterations in cyclin D1 and cyclin-dependent kinase 4 expression in the amygdalae of post-traumatic stress disorder rats

The role of vitamin D3 in follicle development

Vitamin D3 plays a crucial role in female reproduction. As research progresses, the mechanisms of action of vitamin D3 on follicular development have been widely discussed. Firstly, key enzymes involved in the synthesis and metabolism of vitamin D3 have been discovered in the ovary, suggesting that vitamin D3 can be synthesized and metabolized locally within the ovary. Additionally, the detection of vitamin D3 receptors (VDR) in follicles suggests that vitamin D3 may exert its effects by binding specifically to these receptors during follicular development. Further research indicates that vitamin D3 promotes follicular growth by enhancing the development of granulosa cells (GCs) and oocytes. Currently, the mechanism of action of vitamin D3 in follicular development is becoming increasingly clear. Vitamin D3 promotes oocyte development by regulating molecules involved in meiotic arrest in oocytes. It also enhances granulosa cell proliferation by stimulating steroid hormone synthesis and cell cycle regulation. Additionally, vitamin D3 exerts anti-inflammatory effects by reducing oxidative stress and advanced glycation end-products (AGEs), mitigating the detrimental effects of inflammation on follicular development. These functions of vitamin D3 have clinical applications, such as in treating polycystic ovary syndrome (PCOS), improving female fertility, and enhancing outcomes in in vitro fertilization (IVF). This review summarizes the research progress on the role and mechanisms of vitamin D3 in follicular development and briefly summarizes its clinical applications.

Sex-Specific Role for SLIT1 in Regulating Stress Susceptibility

BACKGROUND

Major depressive disorder is a pervasive and debilitating syndrome characterized by mood disturbances, anhedonia, and alterations in cognition. While the prevalence of major depressive disorder is twice as high for women as men, little is known about the molecular mechanisms that drive sex differences in depression susceptibility.

METHODS

We discovered that SLIT1, a secreted protein essential for axonal navigation and molecular guidance during development, is downregulated in the adult ventromedial prefrontal cortex (vmPFC) of women with depression compared with healthy control subjects, but not in men with depression. This sex-specific downregulation of Slit1 was also observed in the vmPFC of mice exposed to chronic variable stress. To identify a causal, sex-specific role for SLIT1 in depression-related behavioral abnormalities, we performed knockdown (KD) of Slit1 expression in the vmPFC of male and female mice.

RESULTS

When combined with stress exposure, vmPFC Slit1 KD reflected the human condition by inducing a sex-specific increase in anxiety- and depression-related behaviors. Furthermore, we found that vmPFC Slit1 KD decreased the dendritic arborization of vmPFC pyramidal neurons and decreased the excitability of the neurons in female mice, effects not observed in males. RNA sequencing analysis of the vmPFC after Slit1 KD in female mice revealed an augmented transcriptional stress signature.

CONCLUSIONS

Together, our findings establish a crucial role for SLIT1 in regulating neurophysiological and transcriptional responses to stress within the female vmPFC and provide mechanistic insight into novel signaling pathways and molecular factors influencing sex differences in depression susceptibility.

The effect of different types of exercise training on diet-induced obesity in rats, cross-talk between cell cycle proteins and apoptosis in testis

Obesity is associated with germ cell apoptosis, spermatogenesis arrest, and testicular endocrine suppression. The aim of the present study was to investigate the crosstalk between germ cell apoptosis and cell cycle machinery in sedentary and obese rats after moderate-intensity continuous (MICT), high-intensity continuous (HICT) and High-intensity interval (HIIT) exercise trainings. Male Wistar rats (n = 30) were randomly divided into 5 groups; the control, sedentary high-fat diet (HFD)-received (HFD-sole), MICT, HICT and HIIT-induced HFD-received groups. The serum levels of LDL-C, HDL-C, triglyceride, and testosterone, mRNA and protein levels of Cyclin D1, Cdk4, p21, apoptotic cell number/mm² of testicular tissue and testicular DNA fragmentation ratio were investigated. The obese animals in HFD-sole group represented a significant (p < 0.05) reduction in serum HDL-C and testosterone levels, Cyclin D1, Cdk4 expressions, and exhibited a remarkable (p < 0.05) increment in LDL-C, triglyceride, p21 expression, apoptotic cell number and DNA fragmentation ratio versus control animals. However, the animals in MICT, HICT, HIIT groups exhibited a significant (p < 0.05) increment in serum HDL-C and testosterone, Cyclin D1 and Cdk4 expressions and showed a significant (p < 0.05) reduction in serum LDL-C and triglyceride, p21 expression, apoptotic cell number and DNA fragmentation versus the HFD-sole group. In conclusion, a crosslink between cell cycle machinery and apoptosis of germ cells was revealed in the testicles of HFD-sole animals, and MICT, HICT and HIIT could ameliorate the obesity-induced impairments, respectively. This effect may be attributed to the effect of exercise training protocols on maintaining Cyclin D1 and Cdk4 and suppressing p21 expression levels in the testicles.

Roles of vitamin D and its receptor in the proliferation and apoptosis of luteinised granulosa cells in the goat

The objective of this study was to investigate the dose-dependent effect of 1α,25-(OH)2VD3 (Vit D3) on invitro proliferation of goat luteinised granulosa cells (LGCs) and to determine the underlying mechanisms of its action by overexpressing and silencing vitamin D receptor (VDR) in LGCs. Results showed that VDR was prominently localised in GCs and theca cells (TCs) and its expression increased with follicle diameter, but was lower in atretic follicles than in healthy follicles. The proliferation rate of LGCs was significantly higher in the Vit D3-treated groups than in the control group, with the highest proliferation rate observed in the 10nM group; this was accompanied by changes in the expression of cell cycle-related genes. These data indicate that Vit D3 affects LGC proliferation in a dose-dependent manner. Contrary to the VDR knockdown effects, its overexpression upregulated and downregulated cell cycle- and apoptosis-related genes respectively; moreover, supplementation with 10nM of Vit D3 significantly enhanced these effects. These results suggest that changes in VDR expression patterns in LGCs may be associated with follicular development by regulation of cell proliferation and apoptosis. These findings will enhance the understanding of the roles of Vit D3 and VDR in goat ovarian follicular development.