Regulation Of Steroidogenesis Research Articles

HIF1\u03b1 is a direct regulator of steroidogenesis in the adrenal gland

Endogenous steroid hormones, especially glucocorticoids and mineralocorticoids, derive from the adrenal cortex, and drastic or sustained changes in their circulatory levels affect multiple organ systems. Although hypoxia signaling in steroidogenesis has been suggested, knowledge on the true impact of the HIFs (Hypoxia-Inducible Factors) in the adrenocortical cells of vertebrates is scant. By creating a unique set of transgenic mouse lines, we reveal a prominent role for HIF1α in the synthesis of virtually all steroids in vivo. Specifically, mice deficient in HIF1α in adrenocortical cells displayed enhanced levels of enzymes responsible for steroidogenesis and a cognate increase in circulatory steroid levels. These changes resulted in cytokine alterations and changes in the profile of circulatory mature hematopoietic cells. Conversely, HIF1α overexpression resulted in the opposite phenotype of insufficient steroid production due to impaired transcription of necessary enzymes. Based on these results, we propose HIF1α to be a vital regulator of steroidogenesis as its modulation in adrenocortical cells dramatically impacts hormone synthesis with systemic consequences. In addition, these mice can have potential clinical significances as they may serve as essential tools to understand the pathophysiology of hormone modulations in a number of diseases associated with metabolic syndrome, auto-immunity or even cancer.

Roles of NR5A1 and NR5A2 in the regulation of steroidogenesis by Clock gene and bone morphogenetic proteins by human granulosa cells.

The functional role of the transcription factors NR5A1 and NR5A2 and their interaction with Clock gene and bone morphogenetic proteins (BMPs) were investigated in human granulosa KGN cells. Treatment with BMP-15 and GDF-9 suppressed forskolin (FSK)-induced steroidogenesis as shown by the mRNA expression levels of StAR and P450scc but not the mRNA expression level of P450arom. Of interest, treatment with BMP-15 and GDF-9 also suppressed FSK-induced NR5A2 mRNA expression. Treatment with BMP-15 suppressed NR5A2 mRNA and protein expression but increased Clock mRNA and protein expression levels by granulosa cells. The mRNA expression levels of NR5A1, but not those of NR5A2, were positively correlated with the levels of Clock mRNA, while the mRNA levels of Id-1, the target gene of BMP signaling, were positively correlated with those of NR5A1 but not with those of NR5A2. It was also demonstrated that the mRNA expression levels of NR5A1 were positively correlated with those of P450arom and 3βHSD, whereas the mRNA expression level of NR5A2 was correlated with those of StAR and P450scc. Furthermore, inhibition of Clock gene expression by siRNA attenuated the expression of NR5A1, and the mRNA levels of Clock gene were significantly correlated with those of NR5A1. Collectively, the results suggested a novel mechanism by which Clock gene expression induced by BMP-15 is functionally linked to the expression of NR5A1, whereas NR5A2 expression is suppressed by BMP-15 in granulosa cells. The interaction between Clock NR5A1/NR5A2 and BMP-15 is likely to be involved in the fine-tuning of steroidogenesis by ovarian granulosa cells.

Nuclear receptors: Key regulators of somatic cell functions in the ovulatory process

The development of the ovarian follicle to its culmination by ovulation is an essential element of fertility. The final stages of ovarian follicular growth are characterized by granulosa cell proliferation and differentiation, and steroid synthesis under the influence of follicle-stimulating hormone (FSH). The result is a population of granulosa cells poised to respond to the ovulatory surge of luteinizing hormone (LH). Members of the nuclear receptor superfamily of transcription factors play indispensable roles in the regulation of these events. The key regulators of the final stages of follicular growth that precede ovulation from this family include the estrogen receptor beta (ESR2) and the androgen receptor (AR), with additional roles for others, including steroidogenic factor-1 (SF-1) and liver receptor homolog-1 (LRH-1). Following the LH surge, the mural and cumulus granulosa cells undergo rapid changes that result in expansion of the cumulus layer, and a shift in ovarian steroid hormone biosynthesis from estradiol to progesterone production. The nuclear receptor best associated with these events is LRH-1. Inadequate cumulus expansion is also observed in the absence of AR and ESR2, but not the progesterone receptor (PGR). The terminal stages of ovulation are regulated by PGR, which increases the abundance of the proteases that are directly responsible for rupture. It further regulates the prostaglandins and cytokines associated with the inflammatory-like characteristics of ovulation. LRH-1 regulates PGR, and is also a key regulator of steroidogenesis, cellular proliferation, and cellular migration, and cytoskeletal remodeling. In summary, nuclear receptors are among the panoply of transcriptional regulators with roles in ovulation, and several are necessary for normal ovarian function.

Prenatal androgen exposure affects ovarian lipid metabolism and steroid biosynthesis in rats.

Prenatal androgen exposure affects reproductive functions and has been proposed as an underlying cause of polycystic ovary syndrome (PCOS). In this study, we aimed to investigate the impact of prenatal androgen exposure on ovarian lipid metabolism and to deepen our understanding of steroidogenesis regulation during adulthood. Pregnant rats were hyperandrogenized with testosterone and female offspring were studied when adult. This treatment leads to two different phenotypes: irregular ovulatory and anovulatory animals. Our results showed that prenatally hyperandrogenized (PH) animals displayed altered lipid and hormonal profile together with alterations in steroidogenesis and ovarian lipid metabolism. Moreover, PH animals showed alterations in the PPARg system, impaired mRNA levels of cholesterol receptors (Ldlr and Srb1) and decreased expression of the rate-limiting enzyme of de novo cholesterol production (Hmgcr). Anovulatory PH animals presented an increase of ovarian cholesteryl esters levels and lipid peroxidation index. Together with alterations in cholesterol metabolism, we found an impairment of the steroidogenic pathway in PH animals in a phenotype-specific manner. Regarding fatty acid metabolism, our results showed, in PH animals, an altered expression of Srebp1 and Atgl, which are involved in fatty acid metabolism and triglycerides hydrolysis, respectively. In conclusion, fatty acid and cholesterol metabolism, which are key players in steroidogenesis acting as a source of energy and substrate for steroid production, were affected in animals exposed to androgens during gestation. These results suggest that prenatal androgen exposure leads to long-term effects that affect ovary lipid metabolism and ovarian steroid formation from the very first steps.

Genetic and Biochemical Markers of Ovarian Function and Their Impact on Women Reproductive Status

Endometriosis is a disease very common nowadays affecting 1-2% of the female population, by estrogen-dependent mechanism. The identification of mutations in the gene encoding for the FSH receptor (FSHR) has been reported since 1995. Physiology teaches us that follicle-stimulating hormone (FSH) is a hormone that is vital in the steroidogenesis regulation mechanisms, while FSH receptor (FSHR) activation helps to promote folliculogenesis and estrogensynthesis. Therefore, studies to show if there are any correlations between endometriosis and FSHR are acquired. Genotyping of FSHR gene polymorphisms were performed using PCR - Restriction Fragment Length Polymorphism (PCR-RFLP) analysis. We analysed a total of 78 patients, 44 infertile patients with endometriosis and 34 controls (non-infertile, pregnant patients). The endometriosis group included women with diagnosis of endo-metriosis confirmed by laparoscopy and /or laparotomy and histological evidence of disease with the endometriosis staging according to American Society for Reproductive Medicine (ASRM). Corroborated with the severity of endometriosis, A919G and A2039G tests found that 71.4% of the M (GG) results were associated with primary infertility, not statistically significant (p=0.994) and 42.9% of the total M results had moderate or severe forms of endometriosis (p = 0.185). The genetic involvement in different pathologies such as endometriosis, has yet to be understood, but knowing more about its mechanism, will help physician target the disease at a more profound level.

Ultrastructural Mechanisms of Impaired Aldosterone Synthesis in Rats Exposed to DDT during Prenatal and Postnatal Development.

The study is aimed at elucidation of ultrastructural mechanisms underlying impaired aldosterone synthesis by glomerulosa cells in Wistar rats exposed to low doses of endocrine disrupter DDT during prenatal and postnatal development. Analysis of rat zona glomerulosa histology and function during the pubertal and postpubertal periods showed that exposure to endocrine disrupter DDT disturbs its development and reduced the production of aldosterone. Electron microscopy showed that changes in the aldosterone synthesis are related to impaired reorganization of the mitochondrial apparatus, one of the leading factors in the regulation of steroidogenesis, in glomerulosa cells in DDT-exposed rats during puberty.

Regulation of Male Fertility by the Renin-Angiotensin System.

The renin-angiotensin system (RAS) is a peptidic system known mainly for its roles in the maintenance of blood pressure and electrolyte and fluid homeostasis. However, several tissues and cells have been described to possess an intrinsic RAS that acts locally through different paracrine and autocrine mechanisms. In the male reproductive system, several components of this system have been observed in various organs and tissues, such as the testes, spermatozoa and seminal fluid. Some functions attributed to this local RAS are maintenance of seminal plasma electrolytes, regulation of steroidogenesis and spermatogenesis, and sperm functions. However, their specific actions in these locations are not fully understood. Therefore, a deep knowledge of the functions of the RAS at both the testicular and seminal levels could clarify its roles in male infertility and sperm physiology, and the different RAS elements could be used to design tools enabling the diagnosis and/or treatment of male infertility.

Role of sox30 in regulating testicular steroidogenesis of common carp

Expression of transcription factors is crucial for the regulation of steroidogenesis and gonadal development in fish. SRY-related box (SOX) proteins regulate gene expression of various events related to vertebrate reproduction. This study reports the role of sox30 and its influence on sox9a/b in regulating testicular steroidogenesis of the common carp, Cyprinus carpio. Tissue distribution showed predominant expression of sox30 in gonads, while gonadal ontogeny indicated significant dimorphic expression of sox30 from 120 days post hatch. Higher sox30 transcripts during the spawning season, an elevation of sox30 after human chorionic gonadotropin induction, and 11-ketotestosterone (11-KT) treatment authenticate gonadotropin dependency. Treatment of 17α–methyl-di-hydroxy-testosterone to juvenile common carp for mono-sex induction, vis-à-vis elevated sox30 expression. Sox30 protein was detected abundantly in spermatocytes and spermatid/sperm of carp testis. Transient silencing of sox30 using small interfering RNAs decreased sox9a/b expression, lead to downregulation of certain molecule/factor, transcription factor, germ/stem cell marker, and steroidogenesis-related enzyme genes. Serum testosterone and 11-KT decreased significantly upon transient silencing of sox30, in vivo. Concomitantly, a reduction in testicular microsomal 11-β hydroxysteroid dehydrogenase activity was observed. These results demonstrate the influence of sox30 as well as sox9a/b in the regulation of testicular steroidogenesis in common carp.

A new role for 14-3-3 protein in steroidogenesis.

Steroidogenic acute regulatory protein (STARD1) is regulated by phosphorylation and 14-3-3 protein binding. STARD1 is a key player in cholesterol transport in mitochondria, and its regulation is not fully understood. Tugaeva et al. provide novel insights on the site-specific phosphorylation and subsequent 14-3-3-dependent regulation of STARD1 function. These results may help us understand the mechanism behind the regulation of steroidogenesis. Comment on: https://doi.org/10.1111/febs.15474.

Molecular basis for the recognition of steroidogenic acute regulatory protein by the 14-3-3 protein family.

Steroidogenesis in adrenals and gonads starts from cholesterol transport to mitochondria. This is mediated by the steroidogenic acute regulatory protein (STARD1), containing a mitochondrial import sequence followed by a cholesterol-binding START domain. Although mutations in this protein have been linked to lipoid congenital adrenal hyperplasia (LCAH), the mechanism of steroidogenesis regulation by STARD1 remains debatable. It has been hypothesized to involve a molten-globule structural transition and interaction with 14-3-3 proteins. In this study, we aimed to address the structural basis for the 14-3-3-STARD1 interaction. We show that, while the isolated START domain does not interact with 14-3-3, this interaction is enabled by STARD1 phosphorylation at Ser57, close to the mitochondrial peptide cleavage site. Biochemical analysis of the STARD1 affinity toward 14-3-3 and crystal structures of 14-3-3 complexes with Ser57 and Ser195 phosphopeptides suggest distinct roles of site-specific phosphorylations in recruiting 14-3-3, to modulate STARD1 activity, processing and import to the mitochondria. Phosphorylation at Ser195 creates a unique conditional site that could only bind to 14-3-3 upon partial unfolding of the START domain. Overall, our findings on the interaction between 14-3-3 and STARD1 may have potential clinical implications for patients with LCAH.

Aster-B coordinates with Arf1 to regulate mitochondrial cholesterol transport

ObjectiveCholesterol plays a pivotal role in mitochondrial steroidogenesis, membrane structure, and respiration. Mitochondrial membranes are intrinsically low in cholesterol content and therefore must be replenished with cholesterol from other subcellular membranes. However, the molecular mechanisms underlying mitochondrial cholesterol transport remains poorly understood. The Aster-B gene encodes a cholesterol binding protein recently implicated in cholesterol trafficking from the plasma membrane to the endoplasmic reticulum (ER). In this study, we investigated the function and underlying mechanism of Aster-B in mediating mitochondrial cholesterol transport. MethodsCRISPR/Cas9 gene editing was carried out to generate cell lines deficient in Aster-B expression. The effect of Aster-B deficiency on mitochondrial cholesterol transport was examined by both confocal imaging analysis and biochemical assays. Deletion mutational analysis was also carried out to identify the function of a putative mitochondrial targeting sequence (MTS) at the N-terminus of Aster-B for its role in targeting Aster-B to mitochondria and in mediating mitochondrial cholesterol trafficking. ResultsAblation of Aster-B impaired cholesterol transport from the ER to mitochondria, leading to a significant decrease in mitochondrial cholesterol content. Aster-B is also required for mitochondrial transport of fatty acids derived from hydrolysis of cholesterol esters. A putative MTS at the N-terminus of Aster-B mediates the mitochondrial cholesterol uptake. Deletion of the MTS or ablation of Arf1 GTPase which is required for mitochondrial translocation of ER proteins prevented mitochondrial cholesterol transport, leading to mitochondrial dysfunction. ConclusionsWe identified Aster-B as a key regulator of cholesterol transport from the ER to mitochondria. Aster-B also coordinates mitochondrial cholesterol trafficking with uptake of fatty acids derived from cholesterol esters, implicating the Aster-B protein as a novel regulator of steroidogenesis.

Growth differentiation factor 9 (gdf9) and bone morphogenetic protein 15 (bmp15) are potential intraovarian regulators of steroidogenesis in Japanese flounder (Paralichthys olivaceus)

Members of transforming growth factor-β (TGF-β) superfamily are vital regulators during the development of fish ovary. However, its intraovarian functions in teleost are still unclear. As members of the TGF-β superfamily, gdf9 and bmp15 are necessary for follicle formation and granulosa cell proliferation. Here in Japanese flounder, quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH) analysis showed that gdf9 and bmp15 were mainly expressed in oogonia and oocytes, whereas weakly expressed in non-ovarian tissues. Overexpression of single gdf9 and the co-overexpression with bmp15 could up-regulate the expression of most steroidogenic genes, while the overexpression of single bmp15 could down-regulate the expression of most steroidogenic genes. These findings demonstrate that single gdf9 and the combination with bmp15 may act as “activator”, while single bmp15 may act as “inhibitor” in the process of steroidogenesis in flounder. This was also verified in negative feedback regulation of gdf9 and bmp15 during hormone treatment. High concentration of human chorionic gonadotropin (hCG) could down-regulate gdf9 and up-regulate bmp15, which were beneficial for the homeostasis of hCG hormone. Besides, knockdown of either gdf9 or bmp15 could significantly down-regulate most steroidogenic genes. This indicated that heterodimer of GDF9:BMP15 might be the most bioactive ligand in gonad development of flounder. Taken together, our study provided a novel recognition that gdf9 and bmp15 could regulate steroidogenesis in teleost through mechanism different from that in mammals.

Is there an impact of the COVID-19 pandemic on male fertility? The ACE2 connection.

The viral pandemic of the coronavirus disease 2019 (COVID-19), generated by a novel mutated severe acute respiratory syndrome coronavirus (SARS-CoV-2), has become a serious worldwide public health emergency, evolving exponentially. While the main organ targeted in this disease is the lungs, other vital organs, such as the heart and kidney, may be implicated. The main host receptor of the SARS-CoV-2 is angiotensin converting enzyme 2 (ACE2), a major component of the renin-angiotensin-aldosterone system (RAAS). The ACE2 is also involved in testicular male regulation of steroidogenesis and spermatogenesis. As the SARS-CoV-2 may have the potential to infect the testis via ACE2 and adversely affect male reproductive system, it is essential to commence with targeted studies to learn from the current pandemic, with the possibility of preemptive intervention, depending on the findings and time course of the continuing pandemic.

SUN-719 The Impact of FOXA3 on Testicular Steroidogenesis

The Forkhead box(Fox) transcription factors are evolutionarily conserved in organisms and regulate diverse biological processes during development as well as adult life. Among the Fox family, FoxA subfamily members Foxa1-3 have been termed `pioneer’ transcription factors as they bind both nucleosome-bound and nucleosome-free DNA targets with the same recognition site. Foxa3 is the only member of FoxA subfamily that is expressed in both male and female gonads. In the testis, Foxa3 is expressed in spermatids and interstitial Leydig cells. We focused our study to elucidate the role of FOXA3 in Leydig cells and its impact on testicular steroidogenesis. Expression of FOXA3 dramatically decreased in mouse Leydig cells during testicular development. In addition, the time-dependent expression of FOXA3 showed an opposite pattern to that of steroidogenic genes in cAMP-induced primary Leydig cells. Meanwhile, Nur77 is among the prime regulators of steroidogenesis in the testicular Leydig cells. Overexpression of FOXA3 in MA-10 cells (mouse Leydig tumor cell line) repressed the cAMP-induced Nur77 promoter activity, which further resulted in the reduced activity of Nur77-target steroidogenic gene promoters (StAR, CYP17A1and 3β-HSD). Similar to above results, the expression of Nur77 and its target genes,StAR, 3β-HSD and CYP11A1, were repressed by adenovirus-mediated overexpression of FOXA3 in mouse primary Leydig cells, although the expression of CYP17A1, another steroidogenic gene, was differentially affected. These results suggest that FOXA3 locally regulates the expression of steroidogenic genes through Nur77 during testicular development.

Temporal changes in the corpus luteum during early pregnancy reveal regulation of pathways that enhance steroidogenesis and suppress luteolytic mechanisms†.

Although rescue of the corpus luteum (CL) is required for pregnancy, luteal function during maternal recognition of pregnancy remains largely unexplored. CL were collected from pregnant cattle on days 14, 17, 20, and 23, to encompass the maternal recognition of pregnancy period. Next-generation sequencing was used to profile mRNA abundance during this time, while tandem mass spectrometry and nanostring technology were used to profile proteins and miRNA, respectively. A total of 1157 mRNA were differentially abundant, while 27 miRNA changed, and 29 proteins tended to change. mRNA that increased were regulators of interferon signaling and DNA repair, while those that decreased were associated with luteolytic processes, such as calcium signaling and matrix metallopeptidase (MMP) signaling, indicating inhibition of these processes. One of these, MMP12, was regulated by prostaglandin F2A in vitro. mRNA that were maximally abundant on day 20 were primarily associated with immune processes. Two of these, C-C motif chemokine ligand 1 and NFKB inhibitor alpha, were regulated by interferon tau in vitro. MiRNA that increased were predicted to inhibit phosphatidylinositol signaling, while those that decreased may be negative regulators of steroidogenesis. One protein that was greater on day 20 than on day 14 was aldehyde dehydrogenase 1 family member A1 (ALDH1A1), which synthesizes retinoic acid. Pharmacological inhibition of this enzyme, or of retinoic acid receptor signaling, led to suppression of progesterone production in vitro. Overall, these data indicate that there are changes in the CL of pregnancy that are important for continued luteal function.

Effect of metformin on testicular expression and localization of leptin receptor and levels of leptin in the diabetic mice

Diabetes mellitus impairs testicular activity and leads to infertility. Leptin is one of the endogenous regulators of the male reproductive functions, but the role of leptin and its receptor (LEPR/Ob-R) in the control of testosterone production and testicular proliferation has not been investigated so far, especially in the Type 1 diabetes mellitus (DM1). Metformin is an anti-hyperglycemic drug which is beneficial for treating the both DM2 and DM1. The aim of this work was to study the possible role of leptin and Ob-R in the regulation of steroidogenesis and proliferation in the testes of mice with streptozotocin-induced DM1 (75 mg/kg/day, 4 days) and to estimate the restoring effect of metformin treatment (500 mg/kg, 2 weeks) on the diabetic testes. In the diabetic testes, the plasma and intratesticular leptin levels and plasma testosterone levels were reduced and completely restored by metformin treatment. Metformin also restored the expression of the steroidogenic transport protein steroidogenic acute regulatory protein reduced in DM1. In the diabetic testes, the expression of Ob-R was downregulated and the immunolocalization of Ob-R showed weak staining in the Leydig cells, the primary spermatocytes and the round spermatids. The germ cell proliferation was also reduced in DM1, as noticed with proliferating cell nuclear antigen (PCNA) expression. Metformin increased the Ob-R expression and immunostaining in the different cell types and improved the PCNA expression. Thus, DM1 impairs the testicular steroidogenesis and proliferation by inhibiting the leptin signaling, causing a decrease in leptin levels and Ob-R expression in the testes of diabetic mice, while metformin improves the leptin signaling and restores testosterone production and testicular proliferation.

Functions of Lysosomes in Mammalian Female Reproductive System

The lysosome is the most acidic membrane-bound intracellular organelle. Lysosomal acidity is primarily maintained by vacuolar H+-ATPase (V-ATPase) and counter ion channels. There are >60 hydrolytic enzymes in the lysosome for its fundamental digestive role. Lysosomes also play important roles in endocytosis, exocytosis, autophagy, and cell death. Studies that have implicated roles of lysosomes in the female reproductive system are reviewed here. In the ovary, lysosomes are implicated in the preparation of free cholesterol for steroidogenesis and degradation of regulators of steroidogenesis, regulation of follicular atresia, follicle rupture during ovulation, luteal cell survival, and luteal regression. In the oviduct, lysosomes are involved in endocytosis of both serum and oviductal luminal components. In the uterus during the menstrual/estrous cycle, lysosomes are associated with endometrial secretion, apoptosis, and menstruation. In the uterus during early pregnancy, lysosomes are involved in the temporal and directional changes of endocytosis, uterine epithelial acidification upon embryo implantation initiation, and embryo-maternal mutual communications via extracellular vesicles. In the placenta, lysosomes are implicated in nutrient transport and placental separation from the uterus for parturition. In the mammary gland, lysosomes are important for mammary gland development and involution. These findings suggest/demonstrate functions of lysosomes in multiple processes of female reproduction, from ovulation to ovarian steroidogenesis for pregnancy maintenance, and from essential in utero nurturing of developing embryos/fetuses via embryo/fetal-maternal communications, to optional postpartum nurturing of newborns via lactation. Future studies using genetically or modified animal models and pharmacological approaches will provide novel insights into the functions and mechanisms of lysosomes in the mammalian female reproductive system.

Взаимосвязь между уровнями адипокинов, их соотношением в фолликулярной жидкости и результативностью экстракорпорального оплодотворения у женщин с нормальной и повышенной массой тела

Adipokines produced by adipose tissue are involved in the regulation of steroidogenesis and folliculogenesis and affect embryo implantation and endometrial receptivity. As a result, the adipokine levels and their ratio in the follicular fluid can be used to evaluate the effectiveness of the in vitro fertilization (IVF). The aim was to study the effect of the leptin, adiponectin and ghrelin levels and their ratios in the follicular fluid of women with the normal and increased body weight on the effectiveness and outcome of IVF. We studied women with normal body weight who became pregnant (PN, n = 7) or who did not become pregnant (nPN, n = 14) as a result of IVF, and overweight women (BMI > 25 kg/m2), who became pregnant (PO, n = 5) and not pregnant (nPO, n = 19) after IVF. In the PN group, the level of leptin in the follicular fluid was higher than in the nPN group (p < 0.05). In the PO and nPO groups, it did not differ, but was higher than in the groups with normal body weight. In the PN group, the ghrelin level was lower than in the nPN group (p < 0.05), while in the PO and nPO groups it was comparable. The leptin/adiponectin ratio in the PN group was higher than in the nPN group (7.05±0.84 versus 2.97±0.44, p < 0.05), but lower than in the PO (13.80±2.28) and nPO (11.28±1.03) groups. The leptin/ghrelin ratio in the PN group was also higher than in the nPN group (18.46±4.20 vs. 4.07±0.68, p < 0.05), but lower than in the PO (37.46±21.59) and nPO (25.17±3.97) groups. The prognostic significance of the leptin/ghrelin ratio was 25.13 (CI 1.24-509.15, p = 0.035). The adiponectin levels and the adiponectin/ghrelin ratio in the investigated groups did not differ. Thus, the prognostic significance of the leptin and ghrelin levels and the leptin/ghrelin and leptin/adiponectin ratios in the follicular fluid is due to the patient’s body weight and metabolic status. The concentration of leptin and the ratio of leptin/ghrelin in the follicular fluid can be considered as valuable markers for assessing the success of IVF in women with normal body weight.

The role of miRNAs in regulating adrenal and gonadal steroidogenesis.

miRNAs are endogenous noncoding single-stranded small RNAs of ~22 nucleotides in length that post-transcriptionally repress the expression of their various target genes. They contribute to the regulation of a variety of physiologic processes including embryonic development, differentiation and proliferation, apoptosis, metabolism, hemostasis and inflammation. In addition, aberrant miRNA expression is implicated in the pathogenesis of numerous diseases including cancer, hepatitis, cardiovascular diseases and metabolic diseases. Steroid hormones regulate virtually every aspect of metabolism, and acute and chronic steroid hormone biosynthesis is primarily regulated by tissue-specific trophic hormones involving transcriptional and translational events. In addition, it is becoming increasingly clear that steroidogenic pathways are also subject to post-transcriptional and post-translational regulations including processes such as phosphorylation/dephosphorylation, protein‒protein interactions and regulation by specific miRNAs, although the latter is in its infancy state. Here, we summarize the recent advances in miRNA-mediated regulation of steroidogenesis with emphasis on adrenal and gonadal steroidogenesis.

Identification of Sec23ip, Part of 14-3-3γ Protein Network, as a Regulator of Acute Steroidogenesis in MA-10 Leydig Cells.

Testosterone production occurs in the Leydig cells of the testes and is essential for virilization, development, reproduction, and quality of life. Although the steroidogenic proteins involved in cholesterol conversion to testosterone (T) are well characterized, the causes of reduced T during fetal, neonatal, and adult life remain uncertain. It is well established that normal cellular function is achieved through fine-tuning of multiple rather than single protein networks. Our objective was to use mass spectrometry (MS)-based proteomics to identify which cellular pathways, other than the steroidogenic machinery, influence testosterone production in MA-10 mouse tumor Leydig cells. The 14-3-3 family of scaffolds mediate protein-protein interactions facilitating the crosstalk between protein networks. We previously showed that in MA-10 cells, 14-3-3γ is a critical regulator of steroidogenesis. Therefore, identifying proteins that interact with 14-3-3γ during steroidogenesis could provide clues into the other networks involved. Using liquid chromatography (LC)-MS, we identified 688 proteins that interact with 14-3-3γ and thus potentially impact MA-10 cell steroidogenesis. The identified proteins belong to multiple protein networks, including endoplasmic reticulum-Golgi cargo sorting and vesicle biogenesis, micro ribonucleic acid-induced gene silencing, inflammation, and vesicle trafficking, to name a few. We found that silencing one of the candidates, Sec23ip, a protein known to be involved in vesicle trafficking, resulted in decreased steroidogenesis. We further showed that in Sec23ip-silenced MA-10 cells, cholesterol mobilization from the cytoplasmic membrane to mitochondria is impaired. Taken together these data suggest that Sec23ip is involved in cholesterol trafficking to supply cholesterol for acute steroidogenesis through its interactions with 14-3-3γ.