Steroidogenic Acute Regulatory Protein Research Articles

Ovarian multi-omics analysis reveals key rate-limiting enzymes FASN, SCD5, FADS1, 3BHSD, and STAR as potential targets for regulating kidding traits in goats

The kidding traits of goats are an important index of production. However, the molecular regulatory mechanisms of kidding traits in goats have not been fully elucidated. This study aimed to investigate the molecular regulatory network of kidding traits in goats. Multi-omics revealed the enrichment of 10 signaling pathways, with fatty acid biosynthesis, biosynthesis of unsaturated fatty acids, and steroid hormone biosynthesis pathways being closely related to reproduction. Interestingly, the key rate-limiting enzymes, fatty acid synthase (FASN), stearoyl-CoA desaturase 5 (SCD5), fatty acid desaturase 1 (FADS1), 3β-hydroxysteroid dehydrogenase/isomerase (3BHSD), and steroidogenic acute regulatory protein (STAR) enriched in these pathways regulate changes in reproduction-related metabolites. In interference experiments, it was observed that suppressing these key rate-limiting enzymes inhibited the expression of CYP19A1, ESR2, and FSHR. Furthermore, interference inhibited granulosa cell proliferation, caused cell cycle arrest, and promoted apoptosis. Thus, these results suggest that the specific markers of nanny goats with multiple kids are the key rate-limiting enzymes FASN, SCD5, FADS1, 3BHSD, and STAR. These findings may greatly enhance the understanding of regulatory mechanisms that govern goat parturition.

Myo-Inositol and D-Chiro-Inositol Reduce DHT-Stimulated Changes in the Steroidogenic Activity of Adult Granulosa Cell Tumors.

Considering the properties of myo-inositol (MI) and D-chiro-inositol (DCI), which are well known in polycystic ovary syndrome therapy, and the limitations of adult granulosa cell tumor (AGCT) treatment, especially for androgen-secreting tumors, we studied the role of MI and DCI in the androgen-rich environment of AGCTs. For this purpose, we analyzed the mRNA expression of steroidogenic genes and the secretion of progesterone (P4) and 17β-estradiol (E2) in an unstimulated and/or dihydrotestosterone (DHT)-stimulated environment under MI and DCI influence. Thus, we used the HGrC1 and KGN cell lines as in vitro models of healthy and cancerous granulosa cells. We found that DHT, the most potent androgen, increased E2 secretion and steroidogenic acute regulatory protein (StAR) and cytochrome P450 side-chain cleavage gene (CYP11A1) mRNA expression without affecting 450 aromatase (CYP19A1) in AGCTs. However, after the MI and DCI treatment of KGN cells, both compounds strongly reduced StAR and CYP11A1 expression. Interestingly, in DHT-stimulated KGN cells, only DCI alone and its cotreatment with MI reduced both CYP11A1 mRNA and E2 secretion. These findings suggest that CYP11A1 is responsible for the antiestrogenic effect of DCI in the androgen-rich environment of AGCTs. Therefore, MI and DCI could be used as effective agents in the adjuvant treatment of AGCT, but further detailed studies are needed.

Mating behaviour and cholesterol nutritional strategies promoted ovarian development of female swimming crab (Portunus trituberculatus).

Female crabs enter a stage of rapid ovarian development after mating, and cholesterol is a substrate for steroid hormone synthesis. Therefore, in this experiment, an 8-week feeding trial was conducted to investigate the effects of mating treatments (mated crab and unmated crab) and three dietary cholesterol levels (0·09 %, 0·79 % and 1·40 %) on ovarian development, cholesterol metabolism and steroid hormones metabolism of adult female swimming crab (Portunus trituberculatus). The results indicated that crabs fed the diet with 0·79 % cholesterol significantly increased gonadosomatic index (GSI) and vitellogenin (VTG) content than other treatments in the same mating status. Moreover, mated crabs had markedly increased GSI and VTG content in the ovary and hepatopancreas than unmated crabs. The histological observation found that exogenous vitellogenic oocytes appeared in the mated crabs, while previtellogenic oocytes and endogenous vitellogenic oocytes were the primary oocytes in unmated crabs. The transmission electron microscopy analysis showed that when fed diet with 0·79 % cholesterol, the unmated crabs contained more rough endoplasmic reticulum and mated crabs had higher yolk content than other treatments. Furthermore, mating treatment and dietary 0·79 % cholesterol level both promoted cholesterol deposition by up-regulation of the mRNA and protein expression levels of class B scavenger receptors 1 (Srb1), while stimulating the secretion of steroid hormones by up-regulation of the mRNA and protein expression of steroidogenic acute regulatory protein (Star). Overall, the present results indicated that mating behaviour plays a leading role in promoting ovarian development, and dietary 0·79 % cholesterol level can further promote ovarian development after mating.

12547 Spatiotemporal Analysis Of Steroidogenesis Pathway Genes Expression In Mouse Fetal Leydig Cells

Abstract Disclosure: K. Jiang: Other; Self; NIH ORIP P51OD011106&S10OD028626. A. Kothandapani: None. Z. Fu: None. T.W. Kearse: None. J. Jorgensen: Grant Recipient; Self; NIH R01HD090660. Male mouse embryos experience a masculinization programming window (MPW, embryonic day, E13-16), during which a critical threshold of androgens is produced to ensure male-pattern development. Insufficient fetal androgens during the MPW leads to variations of masculinization, such as cryptorchidism and hypospadias. In rodents, fetal Leydig cells (FLC) are the primary source of androgens; however, our knowledge about their maturation and steroid synthesis regulation is limited. Hence, the objective for this research is to reveal spatiotemporal patterns of steroidogenic pathway genes in mouse fetal testes using high-resolution technologies. To understand the temporal aspect of steroidogenesis, we quantified transcript numbers of steroidogenic pathway genes via copy number qPCR from E11 to postnatal day 6 (P6). Results showed a gradual increase in transcripts as FLCs differentiate until E14, which then surge during the MPW until E16, followed by a rapid drop in expression to pre-FLC differentiation levels by the time of birth (P0). The profound changes persisted after data were normalized to FLC numbers, suggesting active stimulation and downregulation phases of transcription regulation. Next, to assess androgen output in relation to gene transcript levels, we collected testes at 24 hour intervals from E12 to P3 to measure progesterone, androstenedione, and testosterone via LC/MS/MS; results are pending. Guided by the temporal expression profile, we examined the spatial patterns of Star (steroidogenic acute regulatory protein) at the onset (E13), peak (E16), and end (P0) of steroidogenesis using single-molecule fluorescent in situ hybridization (smFISH). We were surprised to observe three different stages for Star transcription based on the subcellular localization of it: Stage I-only at gene loci in the nucleus, newly differentiated; Stage II-in both the nucleus and cytoplasm, peak activity; and Stage III-in cytoplasm only, repressed transcription. The proportion of Stage I FLC decreased over time (15% at E13, 2% at E16, and 0.4% at P0). Most (55%) FLCs at E16 were at Stage II, when testes exhibit maximum steroidogenic gene transcript numbers. Stage III FLCs dominated in P0 testes with 68% of the total FLC number, reflecting diminishing steroidogenesis. Of note, we also discovered that the global testis pattern for Star transcripts exhibited a unique pattern. At the onset of differentiation (E13), FLCs accumulated in the middle of the dorsal-ventral axis and at either pole of the anterior-posterior axis. By E16 and at P0, FLCs were evenly distributed throughout the testis. In conclusion, we observed that FLC steroidogenic pathway gene transcription is not synchronized but individual FLCs contribute to global testis androgen output as they differentiate in a coordinated pattern towards maximal output to coordinate masculinization. Presentation: 6/1/2024

12547 Spatiotemporal Analysis Of Steroidogenesis Pathway Genes Expression In Mouse Fetal Leydig Cells

Abstract Disclosure: K. Jiang: Other; Self; NIH ORIP P51OD011106&S10OD028626. A. Kothandapani: None. Z. Fu: None. T.W. Kearse: None. J. Jorgensen: Grant Recipient; Self; NIH R01HD090660. Male mouse embryos experience a masculinization programming window (MPW, embryonic day, E13-16), during which a critical threshold of androgens is produced to ensure male-pattern development. Insufficient fetal androgens during the MPW leads to variations of masculinization, such as cryptorchidism and hypospadias. In rodents, fetal Leydig cells (FLC) are the primary source of androgens; however, our knowledge about their maturation and steroid synthesis regulation is limited. Hence, the objective for this research is to reveal spatiotemporal patterns of steroidogenic pathway genes in mouse fetal testes using high-resolution technologies. To understand the temporal aspect of steroidogenesis, we quantified transcript numbers of steroidogenic pathway genes via copy number qPCR from E11 to postnatal day 6 (P6). Results showed a gradual increase in transcripts as FLCs differentiate until E14, which then surge during the MPW until E16, followed by a rapid drop in expression to pre-FLC differentiation levels by the time of birth (P0). The profound changes persisted after data were normalized to FLC numbers, suggesting active stimulation and downregulation phases of transcription regulation. Next, to assess androgen output in relation to gene transcript levels, we collected testes at 24 hour intervals from E12 to P3 to measure progesterone, androstenedione, and testosterone via LC/MS/MS; results are pending. Guided by the temporal expression profile, we examined the spatial patterns of Star (steroidogenic acute regulatory protein) at the onset (E13), peak (E16), and end (P0) of steroidogenesis using single-molecule fluorescent in situ hybridization (smFISH). We were surprised to observe three different stages for Star transcription based on the subcellular localization of it: Stage I-only at gene loci in the nucleus, newly differentiated; Stage II-in both the nucleus and cytoplasm, peak activity; and Stage III-in cytoplasm only, repressed transcription. The proportion of Stage I FLC decreased over time (15% at E13, 2% at E16, and 0.4% at P0). Most (55%) FLCs at E16 were at Stage II, when testes exhibit maximum steroidogenic gene transcript numbers. Stage III FLCs dominated in P0 testes with 68% of the total FLC number, reflecting diminishing steroidogenesis. Of note, we also discovered that the global testis pattern for Star transcripts exhibited a unique pattern. At the onset of differentiation (E13), FLCs accumulated in the middle of the dorsal-ventral axis and at either pole of the anterior-posterior axis. By E16 and at P0, FLCs were evenly distributed throughout the testis. In conclusion, we observed that FLC steroidogenic pathway gene transcription is not synchronized but individual FLCs contribute to global testis androgen output as they differentiate in a coordinated pattern towards maximal output to coordinate masculinization. Presentation: 6/1/2024

12674 Spatiotemporal Analysis Of Steroidogenesis Pathway Genes Expression In Mouse Fetal Leydig Cells

Abstract Disclosure: K. Jiang: Other; Self; NIH ORIP P51OD011106&S10OD028626. A. Kothandapani: None. Z. Fu: None. T.W. Kearse: None. J. Jorgensen: Grant Recipient; Self; NIH R01HD090660. Male mouse embryos experience a masculinization programming window (MPW, embryonic day, E13-16), during which a critical threshold of androgens is produced to ensure male-pattern development. Insufficient fetal androgens during the MPW leads to variations of masculinization, such as cryptorchidism and hypospadias. In rodents, fetal Leydig cells (FLC) are the primary source of androgens; however, our knowledge about their maturation and steroid synthesis regulation is limited. Hence, the objective for this research is to reveal spatiotemporal patterns of steroidogenic pathway genes in mouse fetal testes using high-resolution technologies. To understand the temporal aspect of steroidogenesis, we quantified transcript numbers of steroidogenic pathway genes via copy number qPCR from E11 to postnatal day 6 (P6). Results showed a gradual increase in transcripts as FLCs differentiate until E14, which then surge during the MPW until E16, followed by a rapid drop in expression to pre-FLC differentiation levels by the time of birth (P0). The profound changes persisted after data were normalized to FLC numbers, suggesting active stimulation and downregulation phases of transcription regulation. Next, to assess androgen output in relation to gene transcript levels, we collected testes at 24 hour intervals from E12 to P3 to measure progesterone, androstenedione, and testosterone via LC/MS/MS; results are pending. Guided by the temporal expression profile, we examined the spatial patterns of Star (steroidogenic acute regulatory protein) at the onset (E13), peak (E16), and end (P0) of steroidogenesis using single-molecule fluorescent in situ hybridization (smFISH). We were surprised to observe three different stages for Star transcription based on the subcellular localization of it: Stage I-only at gene loci in the nucleus, newly differentiated; Stage II-in both the nucleus and cytoplasm, peak activity; and Stage III-in cytoplasm only, repressed transcription. The proportion of Stage I FLC decreased over time (15% at E13, 2% at E16, and 0.4% at P0). Most (55%) FLCs at E16 were at Stage II, when testes exhibit maximum steroidogenic gene transcript numbers. Stage III FLCs dominated in P0 testes with 68% of the total FLC number, reflecting diminishing steroidogenesis. Of note, we also discovered that the global testis pattern for Star transcripts exhibited a unique pattern. At the onset of differentiation (E13), FLCs accumulated in the middle of the dorsal-ventral axis and at either pole of the anterior-posterior axis. By E16 and at P0, FLCs were evenly distributed throughout the testis. In conclusion, we observed that FLC steroidogenic pathway gene transcription is not synchronized but individual FLCs contribute to global testis androgen output as they differentiate in a coordinated pattern towards maximal output to coordinate masculinization. Presentation: 6/1/2024

12674 Spatiotemporal Analysis Of Steroidogenesis Pathway Genes Expression In Mouse Fetal Leydig Cells

Abstract Disclosure: K. Jiang: Other; Self; NIH ORIP P51OD011106&S10OD028626. A. Kothandapani: None. Z. Fu: None. T.W. Kearse: None. J. Jorgensen: Grant Recipient; Self; NIH R01HD090660. Male mouse embryos experience a masculinization programming window (MPW, embryonic day, E13-16), during which a critical threshold of androgens is produced to ensure male-pattern development. Insufficient fetal androgens during the MPW leads to variations of masculinization, such as cryptorchidism and hypospadias. In rodents, fetal Leydig cells (FLC) are the primary source of androgens; however, our knowledge about their maturation and steroid synthesis regulation is limited. Hence, the objective for this research is to reveal spatiotemporal patterns of steroidogenic pathway genes in mouse fetal testes using high-resolution technologies. To understand the temporal aspect of steroidogenesis, we quantified transcript numbers of steroidogenic pathway genes via copy number qPCR from E11 to postnatal day 6 (P6). Results showed a gradual increase in transcripts as FLCs differentiate until E14, which then surge during the MPW until E16, followed by a rapid drop in expression to pre-FLC differentiation levels by the time of birth (P0). The profound changes persisted after data were normalized to FLC numbers, suggesting active stimulation and downregulation phases of transcription regulation. Next, to assess androgen output in relation to gene transcript levels, we collected testes at 24 hour intervals from E12 to P3 to measure progesterone, androstenedione, and testosterone via LC/MS/MS; results are pending. Guided by the temporal expression profile, we examined the spatial patterns of Star (steroidogenic acute regulatory protein) at the onset (E13), peak (E16), and end (P0) of steroidogenesis using single-molecule fluorescent in situ hybridization (smFISH). We were surprised to observe three different stages for Star transcription based on the subcellular localization of it: Stage I-only at gene loci in the nucleus, newly differentiated; Stage II-in both the nucleus and cytoplasm, peak activity; and Stage III-in cytoplasm only, repressed transcription. The proportion of Stage I FLC decreased over time (15% at E13, 2% at E16, and 0.4% at P0). Most (55%) FLCs at E16 were at Stage II, when testes exhibit maximum steroidogenic gene transcript numbers. Stage III FLCs dominated in P0 testes with 68% of the total FLC number, reflecting diminishing steroidogenesis. Of note, we also discovered that the global testis pattern for Star transcripts exhibited a unique pattern. At the onset of differentiation (E13), FLCs accumulated in the middle of the dorsal-ventral axis and at either pole of the anterior-posterior axis. By E16 and at P0, FLCs were evenly distributed throughout the testis. In conclusion, we observed that FLC steroidogenic pathway gene transcription is not synchronized but individual FLCs contribute to global testis androgen output as they differentiate in a coordinated pattern towards maximal output to coordinate masculinization. Presentation: 6/1/2024

Suppressing the expression of steroidogenic acute regulatory protein (StAR) in the myocardium by spironolactone contributes to the improvement of right ventricular remodeling in pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a progressive condition that frequently leads to right ventricular (RV) remodeling. Aldosterone promotes vascular and RV remodeling. The upregulation of steroidogenic acute regulatory protein (StAR) stimulates aldosterone synthesis. However, the expression of StAR in the myocardium under PAH conditions remains unknown. To investigate the expression of StAR in the myocardium and its association with RV remodeling in PAH, utilizing spironolactone as a treatment. A PAH model was created using male Sprague-Dawley rats, which received a subcutaneous injection of Sugen5416 (20 mg/kg) and were exposed to hypoxia (10% O2) for 2 weeks, followed by 2 weeks of normoxia. The animals were then divided into two groups, with one group receiving spironolactone (25 mg/kg/day) for an additional 4 weeks, while the other group did not. H9c2 cells were cultured under hypoxic conditions (37 °C, 1% O2, 5% CO2) with or without spironolactone treatment. In the model rats, RV systolic pressure and the Fulton index, both of which increased upon exposure to Sugen5416 and hypoxia, significantly decreased with spironolactone treatment. In H9c2 cells, hypoxic exposure elevated aldosterone levels, while spironolactone treatment significantly suppressed aldosterone production. Suppression of StAR expression in the myocardium via spironolactone contributes to the improvement of RV remodeling in PAH. Spironolactone may offer a valuable therapeutic strategy for RV remodeling in patients with PAH.

Taste receptor T1R3 regulates testosterone synthesis via the cAMP-PKA-SP1 pathway in testicular Leydig cells

Taste receptor type 1 subunit 3 (T1R3) is a G protein-coupled receptor encoded by the TAS1R3 gene that can be specifically activated by certain sweeteners or umami agents for sweet/umami recognition. T1R3 is a potential target for regulating male reproduction. However, studies on the impact of non-nutritive sweeteners on reproduction are limited. In the present study, we evaluated the impact of the non-nutritive sweeteners (saccharin sodium, sucralose and acesulfame-K) on testosterone synthesis in testicular Leydig cells of Xiang pigs by comparing the relative abundance of mRNA transcripts and protein expression of T1R3, steroidogenic related factors, and intracellular cyclic adenosine monophosphate (cAMP), protein kinase A (PKA), as well as testosterone levels using Western blotting, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). To clarify the specific mechanism, a dual luciferase assay was used to uncover the relationship between the transcription factors and steroidogenic enzyme. The acute intratesticular injection of a typical non-nutritive sweeteners was conducted to verify this impact in mouse. The results showed that saccharin sodium not only enhanced T1R3 expression in Leydig cells of Xiang pigs, but also caused significant increases in testosterone, cAMP, PKA, phosphorylation of specificity protein 1 (p-SP1), total protein of specificity protein 1 (SP1), steroidogenic acute regulatory protein (StAR), and 3β-hydroxysteroid dehydrogenase type 1 (3β-HSD1) (P<0.05). Similarly, treatment of Leydig cells with sucralose and acesulfame-K also increased testosterone level, protein expression of T1R3, 17-α-hydroxylase/17, 20-lyase (CYP17A1), and 3β-HSD1 (P<0.05). Treatment with SQ22536 (an adenylate cyclas inhibitor) or H89 (a PKA inhibitor) significantly reduced saccharin sodium-induced protein levels of p-SP1, StAR, CYP17A1, and 3β-HSD1 (P<0.05). In addition, a dual luciferase assay further demonstrated that SP1 significantly increased the promoter activity of CYP17A1 (P<0.05). When mouse testes were injected with saccharin sodium, T1R3, p-SP1, CYP17A1, and 3β-HSD1 were upregulated, leading to a significant testicular increase in testosterone and cAMP levels (P<0.05). These results suggest a mechanism by which the taste receptor T1R3 regulates testosterone production, and this mechanism may be linked to the cAMP-PKA pathway. Understanding the interrelationship between T1R3 and the cAMP-PKA-SP1 pathway contributes to clarify the regulatory mechanisms of male reproduction.

Neuregulin 1 Signaling Attenuates Tumor Necrosis Factor α-Induced Female Rat Luteal Cell Death.

The corpus luteum (CL) is a transient ovarian endocrine structure that maintains pregnancy in primates during the first trimester and in rodents during the entire pregnancy by producing steroid hormone progesterone (P4). CL lifespan, growth, and differentiation are tightly regulated by survival and cell death signals through luteotrophic and luteolytic factors, including the epidermal growth factor (EGF)-like factor family. Neuregulin 1 (NRG1), a member of the EGF family, mediates its effect through ErbB2/3 receptors. However, the functional role of NRG1 in luteal cells (LCs) is unknown. Thus, this study investigated the role of NRG1 and its molecular mechanism of action in rat LC. Our experimental results suggest a strong positive correlation between steroidogenic acute regulatory protein (StAR) and NRG1 expression in mid-CL and serum P4 and estrogen (E2) production. In contrast, there was a decrease in StAR and NRG1 expression and P4 and E2 production with an increase in tumor necrosis factor α (TNFα) expression in regressing CL. Further in vitro studies in LCs showed that the knockdown of endogenous Nrg1 promoted the expression of proinflammatory and proapoptotic factors and decreased prosurvival factor expression. Subsequently, treatment with exogenous TNFα under these experimental conditions profoundly elevated proinflammatory and proapoptotic factors. Further analysis demonstrated that the phosphorylation status of ErbB2/3, PI3K, Ak strain transforming or protein kinase B (Akt), and ErK1/2 was significantly inhibited under these experimental conditions, whereas the treatment of TNFα further inhibited the phosphorylation of ErbB2/3, PI3K, Akt, and ErK1/2. Collectively, these studies provide new insights into the NRG1-mediated immunomodulatory and prosurvival role in LCs, which may maintain the function of CL.

Integrated stress response mediates HSP70 to inhibit testosterone synthesis in aging testicular Leydig cells

The integrated stress response (ISR) is implicated in age-related diseases, while the molecular chaperone heat shock protein 70 (HSP70) can facilitate proper protein folding. However, the regulatory mechanism of ISR in insufficient testosterone synthesis of aging Leydig cells (LCs) remains unclear. This study aims to elucidate the regulatory role of ISR in inadequate testosterone synthesis of aging LCs. We observed a positive correlation between testosterone and HSP70 levels, which were found to be decreased in elderly men. ISR was detected in testicular tissue from old mice. The expression of testosterone synthesis related protein and the content of testosterone decreased in testicular tissue of old mice. Conversely, inhibition of the integrated stress response in testicular tissue led to an increase in steroid synthase expression among old mice. Furthermore, inhibiting ISR specifically within aging LCs resulted in enhanced protein translation efficiency and increased expression levels of new HSP70 and steroidogenic acute regulatory protein (StAR). These findings suggest that ISR occurrence within aging LCs affects StAR protein expression through regulation of HSP70-mediated translation, consequently impairing testosterone synthesis.

Abstract P148: Loss of Ovarian Estrogen Downregulates Renal Steroidogenesis

Hypertension impacts half of US adults and importantly is more prevalent in men than premenopausal women. Sex hormones, particularly estrogen, have been implicated in this sex-difference. Recently we showed renal medullary estrogenic signaling via the G protein-coupled estrogen receptor 1 promotes sodium excretion in female, but not male, Sprague Dawley (SD) rats which implicates estrogen as a possible female-specific natriuretic factor. This led us to question whether the kidney could produce its own steroids, including estrogen, to respond to salt load changes locally. Evidence in cultured COS-7 and fetal kidney cells indicates the expression and activity of steroidogenic enzymes. Recently, we showed the outer medulla of the female SD rat kidney expresses key enzymes and metabolites involved in sex steroid biosynthesis. It is unknown how ovarian estrogen regulates steroidogenesis in the kidney. We hypothesize that ovarian estrogen stimulates the intrarenal capacity to biosynthesize sex steroids. To test this, we measured mRNA expression of several steroidogenic enzymes in the renal outer medulla of gonadally-intact female or ovariectomized SD rats (N=6). Cholesterol is the initial substrate for steroid synthesis. Thus, we first measured HMG-CoA reductase (HMGCR), the key synthesizing enzyme for cholesterol and steroidogenic acute regulatory protein (StAR), which helps commit cholesterol to steroid synthesis. Ovariectomy (OVX) reduced mRNA expression of both when compared to intact females (HMGCR: 63.5 ± 6.2 vs 100.0 ± 10.7 P=0.0169; StAR: 66.6 ± 12.4 vs 100.0 ± 6.4 P=0.0298). Although not significantly different, OVX seemed to reduce the expression of hydroxysteroid 3-β Dehydrogenase, which converts several intermediate steps in androgen and estrogen synthesis, compared to intact females (73.4 ± 13.3 vs 100.0 ± 9.7 P=0.1283). Hydroxysteroid 17-β Dehydrogenase (17β-HSD) 1, which converts estrone to estradiol, was unchanged in OVX compared to intact females (107.6 ± 13.2 vs 100.0 ± 10.1 P=0.6537). OVX reduced expression of 17β-HSD2 (28.34 ± 7.8 vs 100.0 ± 12.85 P=0.0008) and 17β-HSD3 (71.1 ± 7.5 vs 100.0 ± 5.7 P=0.0097) which interconvert androstenedione and testosterone compared to intact females. Combined these data suggest that ovariectomy blunts the intrarenal machinery for steroidogenesis. Additional experiments are required to test whether menopause downregulates renal sex steroid biosynthesis and predisposes postmenopausal women to hypertension.

Abstract P147: Inappropriate Activation of the Leptin-Aldosterone-Endothelial Mineralocorticoid Receptor Axis Promotes Salt Sensitivity of Blood Pressure in Young Female Mice

While compelling clinical evidence indicates that women are more salt-sensitive than men, the mechanisms of the onset of women’s salt-sensitive blood pressure (SSBP) remain largely elusive. Herein, we employed salt-sensitive (SS)-Balb/C and salt-resistant (SR)-C57Bl/6 mice to investigate the etiopathology of SSBP in females. We hypothesized that a high-salt diet alters the leptin-aldosterone-endothelial mineralocorticoid receptor axis (ECMR), leading to SSBP and vascular dysfunction in young SS-female mice. Eleven-week-old female mice were fed a normal (0.4%, NSD) or a high salt diet (4%, HSD) for 7-days. We implanted radiotelemeters for BP monitoring at baseline, HSD, and in response to the leptin receptor (LepR) blockade combined with HSD. Following euthanasia, mesenteric arteries are isolated to measure vascular function via wire myography. HSD elevated mean arterial pressure in Balb/C (NSD: 98.4±2.3 vs. HSD: 105.1±0.9 mmHg) but not in C57 mice (NSD: 99.3±0.9 vs. HSD: 101.3±0.5 mmHg). However, SS-Balb/C mice showed superior natriuretic function in response to salt loading experiments (NSD: 13.3% vs. HSD: 42.3%) as opposed to C57 mice (NSD: 25.8% vs. HSD: 35.1%) (N=3). HSD feeding notably blunted endothelial relaxation to acetylcholine in Balb/c (NSD: 96.5% vs. HSD: 75.4%, N=7), an effect not seen in C57. SS-Balb/C mice failed to suppress aldosterone and adrenal aldosterone synthase (CYP11B2) levels (protein and transcript) compared to C57 mice. This concomitated a 1.8-fold increase in adrenal steroidogenic acute regulatory (StAR) mRNA in SS-Balb/C mice. HSD raised CYP11B2 protein levels in the visceral adipose tissue (VAT) of Balb/C mice. Leptin regulating CYP11B2 expression; we measured fat mass, leptin, and LepR expression. HSD enhanced fat accumulation (C57: +0.7% vs. Balb/c: +26.5%, N=12), leptin levels, and LepR transcript in the adrenal and VAT only in Balb/C mice. LepR blockade reduced BP in Balb/C mice fed a HSD (HSD: 105.1±0.9 vs. HSD+Allo-aca: 100.3±1.9 mmHg). HSD elevated ECMR expression only in Balb/C mice (N=6). To test the potential role of aldosterone-mediated ECMR activation in SSBP, we employed mice with selective overexpression of MR in endothelial cells (ECMR-OE). ECMR-OE young female mice exhibited impaired endothelial function (N=7), reproducing the effects of HSD. In conclusion, SSBP involves an over-activation of the leptin-aldosterone axis in both adrenal and adipose tissue, along with an escalated ECMR expression in females.

Establishment of Star-edited Y1 cells as a novel in vitro functional assay for STAR.

Genetic variants involving steroidogenic acute regulatory protein cause lipoid congenital adrenal hyperplasia, which is characterized by impaired steroidogenesis in the adrenal glands and gonads. Functional assessment of variant STAR proteins is necessary for accurate genetic diagnosis. Ideally, steroidogenic cells should be used to assess the functionality of STAR proteins, but the presence of endogenous STARs in steroidogenic cells precludes such a method. Here, we generated Star-edited cells from steroidogenic Y1 mouse adrenocortical tumor cells by genome editing. Star-edited Y1 cells exhibited very low but measurable cAMP-dependent pregnenolone production. Furthermore, stimulation of the cAMP pathway for two weeks resulted in the formation of lipid droplets in the cytoplasm of Star-edited Y1 cells, which resembled the histology of the adrenal glands of patients with lipoid congenital adrenal hyperplasia. The steroidogenic defect of Star-edited Y1 cells can be restored by transient over-expression of mouse Star. We found that human STAR can also restore defective steroidogenesis of Star-edited Y1 cells, and were able to construct a novel in vitro system to evaluate human STAR variants. Collectively, we established Star-edited Y1 cells that retain the steroidogenic pathway downstream the Star protein. Star-edited Y1 cells recapitulate the functional and morphological changes of lipoid congenital adrenal hyperplasia, and can be used to evaluate the functionality of human STAR variants.

A STAR for the ages: a 30-year historical perspective of the role of transcription factors in the regulation of steroidogenic acute regulatory gene expression.

The steroidogenic acute regulatory (STAR) protein is an essential cholesterol transporter that shuttles cholesterol from the outer to the inner mitochondrial membrane in the major steroidogenic endocrine organs. It is a key player in the acute regulation of steroid hormone biosynthesis in response to tropic hormone stimulation. Its discovery 30 years ago sparked immediate interest in understanding how STAR action is controlled. Since increased STAR gene expression is a classic feature of the acute regulation of steroidogenesis, a special emphasis was placed on defining the transcriptional regulatory mechanisms that underlie its rapid induction in response to tropic hormone stimulation. These mechanisms include the effects of enhancers, the regulation of chromatin accessibility, the impact of epigenetic factors, and the role of transcription factors. Over the past three decades, understanding the transcription factors that regulate STAR gene expression has been the subject of more than 170 independent scientific publications, making it one of, and if not the best, studied genes in the steroidogenic pathway. This intense research effort has led to the identification of dozens of transcription factors and their related binding sites in STAR 5' flanking (promoter) sequences across multiple species. STAR gene transcription appears to be complex in that a large number of transcription factors have been proposed to interact with either isolated or overlapping regulatory sequences that are tightly clustered over a relatively short promoter region upstream of the STAR transcription start site. Many of these transcription factors appear to work in unique combinatorial codes and are impacted by diverse hormonal and intracellular signaling pathways. This review provides a retrospective overview of the transcription factors proposed to regulate both basal and acute (hormonal) STAR gene expression, and how insights in this area have evolved over the past 30 years.

Sudachitin Alleviates Paraquat Instigated Testicular Toxicity in Albino Rats via Regulating Nrf-2/Keap-1, Inflammatory, Steroidogenic, and Histological Profile.

Paraquat (PQ) is a noxious herbicide which adversely affects the vital organs including male reproductive system. Sudachitin (SCN) is a naturally occurring flavonoid that demonstrates a wide range of biological potentials. The current study was designed to investigate the alleviative potential of SCN to avert PQ-induced testicular toxicity in rats. Forty-eight male rats (Rattus norvegicus) were apportioned into four groups including control, PQ (5 mg/kg), PQ + SCN (5 mg/kg + 30 mg/kg), and SCN (30 mg/kg) only treated group. Our findings elucidated that PQ treatment reduced the expression of nuclear factor erythroid 2-related factor 2 (Nrf-2) and its antioxidant genes as well as the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GSR) and glutathione peroxidase (GPx), while elevating the levels of reactive oxygen species (ROS), and malondialdehyde (MDA). Furthermore, PQ intoxication upregulated the expressions of Keap-1 while downregulating the expression of 3-beta hydroxysteroid dehydrogenase (3β-HSD), 17-beta hydroxysteroid dehydrogenase (17β-HSD), and steroidogenic acute regulatory protein (StAR). Moreover, sperm anomalies were increased following the exposure to PQ. Besides, PQ exposure decreased the levels of plasma testosterone, luteinizing hormone (LH), and follicle stimulating hormone (FSH) while increasing the levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), nuclear factor-kappa B (NF-κB), interleukin-1beta (IL-1β), and cyclooxygenase-2 (COX-2). Additionally, PQ treatment escalated the expressions of cysteinyl aspartate-specific proteases-3 (Caspase-3) and Bcl-2-associated X-protein (Bax) while downregulating the expressions of B-cell lymphoma-2 (Bcl-2). Furthermore, PQ exposure disrupted the normal architecture of testicular tissues. However, SCN treatment remarkably protected the testicular tissues via regulating the aforementioned disruptions owing to its antioxidant, anti-inflammatory, and androgenic potential.

Juglanin cures polyethylene microplastics-induced testicular damage in rats

The current research was planned to evaluate the ameliorative role of juglanin (Jug) against polyethylene microplastics (PEMP) prompted testicular impairments. 48 rats were allocated in 4 groups: control, PEMP exposed, Jug + PEMP co-administrated and Jug supplemented group. The activities of antioxidant enzyme, inflammatory markers level, hormonal level, the expressions of steroidogenic enzymes, pro-apoptotic and anti-apoptotic protein were assessed after the 56 days of the trial. PEMP intoxication significantly disturbed Nrf-2/Keap-1 pathway and the biochemical profile of rats. However, the administration of Jug markedly increased Nrf-2 and anti-oxidant enzymes expressions, besides decreased the Keap-1 expression. Jug administration also increased Catalase (CAT), super oxide dismutase (SOD) glutathione reductase (GPx), glutathione peroxidase (GSR) and Hemeoxygenase-1 (HO-1) activities. On the other hand, the levels of reactive oxygen species (ROS) and malondialdehyde (MDA) were decreased following Jug administration. Moreover, Jug administration decreased the levels of inflammatory markers. Additionally, Jug administration increased luteinizing hormone (LH), testosterone, follicle-stimulating hormone (FSH) levels and steroidogenic enzymes expression including 17β-hydroxysteroid dehydrogenase (17β-HSD), steroidogenic acute regulatory protein (StAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) expressions. Jug administration decreased Caspase-3 and Bax expressions, while increasing Bcl-2 expression. Therefore, the current findings suggested that Jug can remarkably alleviate PEMP induced testicular damage due to its therapeutical potentials.

Cordycepin suppresses steroidogenic acute regulatory protein expression by reducing SP1 in human granulosa-lutein cells.

Cordycepin (COR), a compound derived from Cordyceps, is recognized as an adenosine analog with numerous beneficial effects on human health. However, its impact on steroidogenic acute regulatory protein (STAR) expression in ovarian granulosa cells is not well understood. This study demonstrates that COR downregulates STAR expression by reducing the expression of the SP1 transcription factor. Cordycepin (COR), a pure compound of Cordyceps, is known as an adenosine analog that exerts many beneficial effects on human health. The steroidogenesis mediated by ovarian granulosa cells is pivotal in maintaining normal female reproductive function. The steroidogenic acute regulatory protein (STAR) regulates the rate-limiting step in steroidogenesis. COR has been shown to stimulate STAR expression in mouse Leydig cells, the steroidogenic cells in the testes. However, the effect of COR on STAR expression in ovarian granulosa cells remains undetermined. In the present study, we show that treatment with COR downregulates STAR expression in a steroidogenic human granulosa-like tumor cell line, KGN, and primary culture of human granulosa-lutein (hGL) cells obtained from patients undergoing in vitro fertilization. We used specific adenosine receptor (AR) antagonists, and our results reveal that the inhibitory effect of COR on STAR expression is mediated by AR-A1, AR-A2A, and AR-A3. In both KGN and primary hGL cells, COR activates ERK1/2 and AKT signaling pathways, but only activation of ERK1/2 is required for the COR-induced downregulation of STAR expression. In addition, our results demonstrate that COR downregulates STAR expression by reducing the expression of the SP1 transcription factor. These results provide a better understanding of the biological function of COR on STAR expression in the ovary, which may lead to the development of alternative therapeutic approaches for female reproductive disorders.

Acetylation of Steroidogenic Acute Regulatory Protein Sensitizes 17β-Estradiol Regulation in Hormone-Sensitive Breast Cancer Cells.

An imbalance in estrogen signaling is a critical event in breast tumorigenesis. The majority of breast cancers (BCs) are hormone-sensitive; they majorly express the estrogen receptor (ER+) and are activated by 17β-estradiol (E2). The steroidogenic acute regulatory protein (StAR) mediates the rate-limiting step in steroid biosynthesis. The dysregulation of the epigenetic machinery, modulating E2 levels, is a primary occurrence for promoting breast tumorigenesis. StAR expression, concomitant with E2 synthesis, was reported to be aberrantly high in human and mouse hormone-dependent BC cells compared with their non-cancerous counterparts. However, the mechanism of action of StAR remains poorly understood. We discovered StAR as an acetylated protein and have identified a number of lysine (K) residues that are putatively acetylated in malignant and non-malignant breast cells, using LC-MS/MS (liquid chromatography-tandem mass spectrometry), suggesting they differently influence E2 synthesis in mammary tissue. The treatment of hormone-sensitive MCF7 cells with a variety of histone deacetylase inhibitors (HDACIs), at therapeutically and clinically relevant doses, identified a few additional StAR acetylated lysine residues. Among a total of fourteen StAR acetylomes undergoing acetylation and deacetylation, K111 and K253 were frequently recognized either endogenously or in response to HDACIs. Site-directed mutagenesis studies of these two StAR acetylomes, pertaining to K111Q and K253Q acetylation mimetic states, resulted in increases in E2 levels in ER+ MCF7 and triple negative MB-231 BC cells, compared with their values seen with human StAR. Conversely, these cells carrying K111R and K253R deacetylation mutants diminished E2 biosynthesis. These findings provide novel and mechanistic insights into intra-tumoral E2 regulation by elucidating the functional importance of this uncovered StAR post-translational modification (PTM), involving acetylation and deacetylation events, underscoring the potential of StAR as a therapeutic target for hormone-sensitive BC.

Hexavalent chromium reduces testosterone levels by impairing lipophagy and disrupting lipid metabolism homeostasis: Based on a metabolomic analysis

Hexavalent chromium (Cr(VI)) causes testicular damage and reduces testosterone secretion. Testosterone synthesis relies on cholesterol as a raw material, and its availability can be affected by lipophagy. However, the role of lipophagy in Cr(VI)-induced testicular damage and reduced testosterone secretion remains unclear. In this study, we investigated the effect of Cr(VI) on lipid metabolism and lipophagy in the testes of ICR mice. Forty mice were randomly divided into four groups and exposed to different doses of Cr(VI) (0, 75, 100, 125 mg/kg) for thirty days. Cr(VI) increased the rate of sperm abnormalities, decreased testosterone level, and decreased the levels of testosterone synthesis-related proteins, namely steroidogenic acute regulatory (StAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) proteins. Through metabolomic analysis, Oil Red O staining, and biochemical indicator (triglyceride and total cholesterol) analysis, Cr(VI) was found to disrupt testicular lipid metabolism. Further investigation revealed that Cr(VI) inhibited the AMP-activated protein kinase (AMPK)/sterol regulatory element-binding protein 1 (SREBP1) pathway, elevated levels of the autophagy-related proteins microtubule-associated protein 1 light chain 3B (LC3B) and sequestosome 1 (SQSTM1)/P62 and lipophagy-related proteins Rab7 and Rab10, while increasing colocalization of LC3B and Perilipin2. These findings suggest that Cr(VI) exposure leads to abnormal lipid metabolism in the testes by suppressing the AMPK/SREBP1 pathway and disrupting lipophagy, ultimately reducing testosterone level and inducing testicular damage.