Stress-induced glucocorticoids alter the Leydig cells' timing and steroidogenesis-related systems

REVERBA couples the circadian clock to Leydig cell steroidogenesis

The involvement of the molecular clock in regulating cell physiological processes on a specific time scale is a recognized concept, yet its specific impact on optimizing androgen production in Leydig cells has been unclear. This study aimed to confirm the role of the REVERBA (NR1D1) gene in controlling the transcription of key genes related to Leydig cell steroid production. We investigated daily variations by collecting Leydig cells from rats at various times within a 24-h period. Chromatin immunoprecipitation study showed a time-dependent pattern for genes linked to steroid production (Nur77, Star, Cyp11a1, and Cyp17a1), which closely matched the 24-h REVERBA levels in Leydig cells, peaking between zeitgeber time (ZT) 7-11. To understand the physiological significance of REVERBA's interaction with promoters of steroidogenesis-related genes, Leydig cells from rats at two different times (ZT7 and ZT16; chosen based on REVERBA expression levels), were treated with either an agonist (GSK4112) or an antagonist (SR8278). The results revealed that the REVERBA agonist stimulated gene transcription, while the antagonist inhibited it, but only when REVERBA was sufficiently present, indicating a reliance on REVERBA's circadian fluctuation. Moreover, this REVERBA-dependent stimulation had a clear impact on testosterone production in the culture medium, underscoring REVERBA's involvement in the circadian regulation of testosterone. This study indicates that REVERBA, in addition to being a core component of the cellular clock, plays a key role in regulating androgen production in Leydig cells by influencing the transcription of critical steroidogenesis-related genes.

Interactive metabolic signatures of testicular testosterone with bilateral adrenalectomy in mice

The hypothalamic-pituitary-adrenal (HPA) and hypothalamic-pituitary-gonadal (HPG) axes have reciprocal relationships with steroidogenesis regulation. However, the relationship between testicular steroids and defective glucocorticoid production under chronic stress remains unclear. Metabolic changes of testicular steroids in bilateral adrenalectomized (bADX) 8-week-old C57BL/6 male mice were measured using gas chromatography-mass spectrometry. Twelve weeks after surgery, testis samples were obtained from the model mice, which were divided into tap-water (n = 12) and 1% saline (n = 24) supplementation groups, and their testicular steroid levels were compared with those of sham controls (n = 11). An increased survival rate with lower testicular levels of tetrahydro-11-deoxycorticosterone was observed in the 1% saline group compared to both the tap-water (p = 0.029) and sham (p = 0.062) groups. Testicular corticosterone levels were significantly decreased in both tap-water (4.22 ± 2.73ng/g, p = 0.015) and 1% saline (3.70 ± 1.69, p = 0.002) groups compared to those in sham controls (7.41 ± 7.39). Testicular testosterone levels tended to increase in both bADX groups compared to those in the sham controls. In addition, increased metabolic ratios of testosterone to androstenedione in tap-water (2.24 ± 0.44, p < 0.05) and 1% saline (2.18 ± 0.60, p < 0.05) mice compared to sham controls (1.87 ± 0.55) suggested increased production of testicular testosterone. No significant differences in serum steroid levels were observed. Defective adrenal corticosterone secretion and increased testicular production in bADX models revealed an interactive mechanism underlying chronic stress. The present experimental evidence suggests the crosstalk between the HPA and HPG axes in homeostatic steroidogenesis.

Profound Effects of Dexamethasone on the Immunological State, Synthesis and Secretion Capacity of Human Testicular Peritubular Cells

The functions of human testicular peritubular cells (HTPCs), forming a small compartment located between the seminiferous epithelium and the interstitial areas of the testis, are not fully known but go beyond intratesticular sperm transport and include immunological roles. The expression of the glucocorticoid receptor (GR) indicates that they may be regulated by glucocorticoids (GCs). Herein, we studied the consequences of the GC dexamethasone (Dex) in cultured HTPCs, which serves as a unique window into the human testis. We examined changes in cytokines, mainly by qPCR and ELISA. A holistic mass-spectrometry-based proteome analysis of cellular and secreted proteins was also performed. Dex, used in a therapeutic concentration, decreased the transcript level of proinflammatory cytokines, e.g., IL6, IL8 and MCP1. An siRNA-mediated knockdown of GR reduced the actions on IL6. Changes in IL6 were confirmed by ELISA measurements. Of note, Dex also lowered GR levels. The proteomic results revealed strong responses after 24 h (31 significantly altered cellular proteins) and more pronounced ones after 72 h of Dex exposure (30 less abundant and 42 more abundant cellular proteins). Dex also altered the composition of the secretome (33 proteins decreased, 13 increased) after 72 h. Among the regulated proteins were extracellular matrix (ECM) and basement membrane components (e.g., FBLN2, COL1A2 and COL3A1), as well as PTX3 and StAR. These results pinpoint novel, profound effects of Dex in HTPCs. If transferrable to the human testis, changes specifically in ECM and the immunological state of the testis may occur in men upon treatment with Dex for medical reasons.

Stress alters the transcriptional activity of Leydig cells dependently on the diurnal time

The increasing amount of data points to the circadian timing system as an essential part of processes regulating androgen homeostasis. However, the relationship between stress response, timekeeping-, and steroidogenesis-related systems is unexplored. Here, the stress-response of the testosterone-producing rat Leydig cells depending on the time of stressful events was studied. The study analyzes the effects of 3-hour immobilization (IMO) applied at different periods during the day. The IMO performed once (1xIMO) or repeated in 10 consecutive days (10xIMO). Both types of IMO increased corticosterone and decreased testosterone blood level. However, the effect of 10xIMO occurring in the active phase on blood testosterone was less pronounced. This is related to different sensitivity to IMO-events depending on the diurnal time. Most steroidogenesis-related genes (Lhcgr, Cyp11a1, Hsd3b1/2, Cyp17a1) were down-regulated in the inactive but unchanged or even up-regulated in the active phase of the day. Both types of IMO stimulated the expression of clock elements Bmal1/BMAL1, Per1/PER1 regardless of the day's stage and reduced Rev-erba in the inactive phase. The principal-component-analysis (PCA) confirmed a major shift, for both IMO-types, in the transcription of the genes across the passive/active stage. Further, 10xIMO changed a diurnal pattern of the glucocorticoid receptor (Nr3c1/GR) expression while the observed time-dependent IMO-response of the Leydig cells correlated with different corticosterone engagements. Altogether, the Leydig cell's stress-response depends on the daytime of the stressful event, emphasizing the importance of the circadian-system in supporting androgen homeostasis and male fertility.

Mutual Shaping of Circadian Body-Wide Synchronization by the Suprachiasmatic Nucleus and Circulating Steroids

Background

Steroids are lipid hormones that reach bodily tissues through the systemic circulation, and play a major role in reproduction, metabolism, and homeostasis. All of these functions and steroids themselves are under the regulation of the circadian timing system (CTS) and its cellular/molecular underpinnings. In health, cells throughout the body coordinate their daily activities to optimize responses to signals from the CTS and steroids. Misalignment of responses to these signals produces dysfunction and underlies many pathologies.

Questions Addressed

To explore relationships between the CTS and circulating steroids, we examine the brain clock located in the suprachiasmatic nucleus (SCN), the daily fluctuations in plasma steroids, the mechanisms producing regularly recurring fluctuations, and the actions of steroids on their receptors within the SCN. The goal is to understand the relationship between temporal control of steroid secretion and how rhythmic changes in steroids impact the SCN, which in turn modulate behavior and physiology.

Evidence Surveyed

The CTS is a multi-level organization producing recurrent feedback loops that operate on several time scales. We review the evidence showing that the CTS modulates the timing of secretions from the level of the hypothalamus to the steroidogenic gonadal and adrenal glands, and at specific sites within steroidogenic pathways. The SCN determines the timing of steroid hormones that then act on their cognate receptors within the brain clock. In addition, some compartments of the body-wide CTS are impacted by signals derived from food, stress, exercise etc. These in turn act on steroidogenesis to either align or misalign CTS oscillators. Finally this review provides a comprehensive exploration of the broad contribution of steroid receptors in the SCN and how these receptors in turn impact peripheral responses.

Conclusion

The hypothesis emerging from the recognition of steroid receptors in the SCN is that mutual shaping of responses occurs between the brain clock and fluctuating plasma steroid levels.

Spermatozoal Mitochondrial Dynamics Markers and Other Functionality-Related Signaling Molecules Exert Circadian-like Response to Repeated Stress of Whole Organism

In the search for the possible role of the mitochondrial dynamics markers in spermatozoa adaptation, an in vivo approach was designed to mimic situations in which human populations are exposed to 3 h of repeated psychological stress (the most common stress in human society) at different time points during the day (24 h). The hormones (stress hormone corticosterone and testosterone), the number and the functionality of spermatozoa (response to acrosome-reaction-inducer progesterone), as well as the transcriptional profiles of 22 mitochondrial dynamics and function markers and 22 signaling molecules regulating both mitochondrial dynamics and spermatozoa number and functionality were followed at three time points (ZT3, ZT11, and ZT23). The results show that repeated stress significantly decreased the number and functionality of spermatozoa at all time points. In the same samples, the transcriptional profiles of 91% (20/22) of mitochondrial dynamics and functionality markers and 86% (19/22) of signaling molecules were disturbed after repeated stress. It is important to point out that similar molecular changes in transcriptional profiles were observed at ZT3 and ZT23, but the opposite was observed at ZT11, suggesting the circadian nature of the adaptive response. The results of PCA analysis show the significant separation of repeated stress effects during the inactive/light and active/dark phases of the day, suggesting the circadian timing of molecular adaptations.

Spermatozoa Develop Molecular Machinery to Recover From Acute Stress

This study was designed to search for the possible mechanism(s) of male (in/sub)fertility by following the molecular response of spermatozoa on acute psychological stress (the most common stress in human society) and on a 20-h time-dependent recovery period. To mimic in vivo acute stress, the rats were exposed to immobilization once every 3 h. The recovery periods were as follows: 0 (immediately after stress and 3 h after the light is on-ZT3), 8 (ZT11), 14 (ZT17), and 20 (ZT23) h after stress. Results showed that acute stress provoked effects evident 20 h after the end of the stress period. Numbers of spermatozoa declined at ZT17 and ZT23, while functionality decreased at ZT3 and ZT11, but recovered at ZT17 and ZT23. Transcriptional profiles of 91% (20/22) of tracked mitochondrial dynamics and functionality markers and 91% (20/22) of signaling molecules regulating both mitochondrial dynamics and spermatozoa number/functionality were disturbed after acute stress and during the recovery period. Most of the changes presented as increased transcription or protein expression at ZT23. The results of the principal component analysis (PCA) showed the clear separation of acute stress recovery effects during active/dark and inactive/light phases. The physiological relevance of these results is the recovered positive-acrosome-reaction, suggesting that molecular events are an adaptive mechanism, regulated by acute stress response signaling. The results of the PCA confirmed the separation of the effects of acute stress recovery on gene expression related to mitochondrial dynamics, cAMP, and MAPK signaling. The transcriptional patterns were different during the active and inactive phases. Most of the transcripts were highly expressed during the active phase, which is expected given that stress occurred at the beginning of the inactive phase. To the best of our knowledge, our results provide a completely new view and the first presentation of the markers of mitochondrial dynamics network in spermatozoa and their correlation with signaling molecules regulating both mitochondrial dynamics and spermatozoa number and functionality during recovery from acute stress. Moreover, the interactions between the proteins important for spermatozoa homeostasis and functionality (MFN2 and PRKA catalytic subunit, MFN2 and p38MAPK) are shown for the first time. Since the existing literature suggests the importance of semen quality and male fertility not only as the fundamental marker of reproductive health but also as the fundamental biomarkers of overall health and harbingers for the development of comorbidity and mortality, we anticipate our result to be a starting point for more investigations considering the mitochondrial dynamics markers or their transcriptional profiles as possible predictors of (in/sub)fertility.