Efficiency of the sulfate pathway in comparison to the Δ4- and Δ5-pathway of steroidogenesis in the porcine testis

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.

Sirtuin 1-mediated autophagy regulates testosterone synthesis in Leydig cells of piglets

Testosterone is secreted by Leydig cells (LCs), which play an important physiological role in preserving male secondary sex characteristics, protecting male reproductive function, and establishing the blood-testis barrier. Studies have shown that autophagy is particularly active in LCs; however, its involvement in testosterone synthesis in porcine LCs has not been fully explored. Therefore, this experiment aimed to investigate the influence of autophagy on testosterone secretion in porcine LCs and its potential regulatory mechanism. Our results demonstrated that both testicular autophagy and serum testosterone levels increased in piglets during postnatal development from 4 to 18 weeks. In addition, autophagy was found to degrade the Na+/H+ exchange regulatory factor 2 (NHERF2), leading to the up-regulation of scavenger receptor class B type 1 (SRB1). This process resulted in increased cholesterol intake and enhanced testosterone production. The observable level of sirtuin 1 (SIRT1) was directly proportional to the level of autophagy. In vitro investigations have shown that SIRT1 can affect the level of autophagy, cholesterol uptake as well as testosterone release. In conclusion, testosterone synthesis during pig development is regulated by SIRT1. SIRT1 mediates the degradation of NHERF2 through autophagy, thereby weakening its negative regulatory effect on the high-density lipoprotein receptor SRB1 in Leydig cells. This process increases cholesterol uptake and enhances testosterone synthesis.

Androgen synthesis cell-specific CREBZF deficiency alters adrenal cortex steroid secretion and develops behavioral abnormalities in adult male mice

The global challenge of male infertility is escalating, notably due to the decreased testosterone (T) synthesis in testicular Leydig cells under stress, underscoring the critical need for a more profound understanding of its regulatory mechanisms. CREBZF, a novel basic region-leucine zipper transcription factor, regulates testosterone synthesis in mouse Leydig cells in vitro; however, further validation through in vivo experiments is essential. Our study utilized Cyp17a1-Cre to knock out CREBZF in androgen-synthesis cells and explored the physiological roles of CREBZF in fertility, steroid hormone synthesis, and behaviors in adult male mice. Conditional knockout (cKO) CREBZF did not affect fertility and serum testosterone level in male mice. Primary Leydig cells isolated from CREBZF-cKO mice showed impaired testosterone secretion and decreased mRNA levels of Star, Cyp17a1, and Hsd3b1. Loss of CREBZF resulted in thickening of the adrenal cortex, especially X-zone, with elevated serum corticosterone and dehydroepiandrosterone levels and decreased serum dehydroepiandrosterone sulfate levels. Immunohistochemical staining revealed increased expression of StAR, Cyp11a1, and 17β-Hsd3 in the adrenal cortex of CREBZF-cKO mice, while the expression of AR was significantly reduced. Along with the histological changes and abnormal steroid levels in the adrenal gland, CREBZF-cKO mice showed higher anxiety-like behavior and impaired memory in the elevated plus maze and Barnes maze, respectively. In summary, CREBZF is dispensable for fertility, and CREBZF deficiency in Leydig cells promotes adrenal function in adult male mice. These results shed light on the requirement of CREBZF for fertility, adrenal steroid synthesis, and stress response in adult male mice, and contribute to understanding the crosstalk between testes and adrenal glands.

The co-expression of steroidogenic enzymes with T1R3 during testicular development in the Congjiang Xiang pig

Testosterone is a key crucial hormone synthesized by steroidogenic enzymes that initiate and maintain spermatogenesis and secondary sexual characteristics in adult males. The taste receptor family 1 subunit 3 (T1R3) is reported to be associated with male reproduction. T1R3 can regulate the expressions of steroidogenic enzymes and affect testosterone synthesis. In this study, we addressed the question of whether the expression of steroid synthase was associated with T1R3 and its downstream-tasting molecules during testicular development. The results showed an overall upward trend in testosterone and morphological development in testes from Congjiang Xiang pigs from pre-puberty to sexual maturity. Gene expression levels of testicular steroidogenic acute regulatory protein (StAR), 3β-hydroxysteroid dehydrogenase (3β-HSD), cytochrome P450c17 (CYP17A1) and 17β-hydroxysteroid dehydrogenase (17β-HSD) were increased from pre-puberty to sexual maturity. Protein expression changes of CYP17A1 and 3β-HSD were consistent with mRNA. The relative abundance of tasting molecules (TAS1R3, phospholipase Cβ2, PLCβ2) was increased from pre-puberty to puberty (P < 0.05), with no further significant changes in expression from puberty to sexual maturity. Steroidogenic enzymes (3β-HSD and CYP17A1) were strongly detected in Leydig cells from pre-puberty to sexual maturity, while tasting molecules were localized in Leydig cells and spermatogenic cells. Correlation analysis showed that the genes mentioned above (except for PLCβ2) were positively correlated with testosterone levels and morphological characteristics of the testes at different developmental stages of Congjiang Xiang pigs. These results suggest that steroidogenic enzymes regulate testosterone synthesis and testicular development, and that taste receptor T1R3, but not PLCβ2, may associate with this process.

CYP19A1 May Influence Lambing Traits in Goats by Regulating the Biological Function of Granulosa Cells

Simple Summary

Aromatase (CYP19A1), a member of the cytochrome family, is widely expressed in ovarian and granulosa cells and is primarily responsible for the conversion of androgens to estrogens. Increased expression of CYP19A1 in follicular granulosa cells has implications for cell proliferation, steroid hormone secretion, and the expression of related functional indicator genes. We hypothesize that CYP19A1 may indirectly influence lambing numbers in goats by regulating follicular cell growth and development, as well as ovarian ovulation.

Abstract

Abnormal expression of CYP19A1, a gene related to steroid hormone synthesis, causes steroid hormone disruption and leads to abnormal ovulation in granulosa cells. However, the exact mechanism of CYP19A1 regulation is unclear. In this study, we confirmed the localization of CYP19A1 in goat ovarian tissues using immunohistochemistry. Subsequently, we investigated the effects of CYP19A1 on granulosa cell proliferation, steroid hormone secretion, and expression of candidate genes for multiparous traits by overexpressing and silencing CYP19A1 in goat granulosa cells (GCs). The immunohistochemistry results showed that CYP19A1 was expressed in all types of follicular, luteal, and granulosa cells, with subcellular localization results revealing that CYP19A1 protein was mainly localized in the cytoplasm and nucleus. Overexpression of CYP19A1 significantly increased the mRNA levels of CYP19A1, FSHR, and INHBA, which are candidate genes for multiple birth traits in goats. It also promoted cell proliferation, PCNA and Cyclin E mRNA levels in granulosa cells, and secretion of estrogen and progesterone. However, it inhibited the mRNA levels of STAR, CYP11A1, and 3βSHD, which are genes related to steroid synthesis. Silencing CYP19A1 expression significantly reduced CYP19A1, FSHR, and INHBA mRNA levels in granulosa cells and inhibited granulosa cell proliferation and PCNA and Cyclin E mRNA levels. It also reduced estrogen and progesterone secretion but enhanced the mRNA levels of STAR, CYP11A1, and 3βSHD. CYP19A1 potentially influenced the lambing traits in goats by affecting granulosa cell proliferation, hormone secretion, and expression of candidate genes associated with traits for multiple births.

Steroid sulfates in domestic mammals and laboratory rodents

Historically steroid sulfates have been considered predominantly as inactive metabolites. It was later discovered that by cleavage of the sulfate residue by steroid sulfatase (STS), they can be (re-)converted into active forms or into precursors for the local production of active steroids. This sulfatase pathway is now a very active field of research, which has gained considerable interest particularly in connection with the steroid metabolism of human steroid hormone-dependent cancer tissue. In comparison, there is much less information available on the occurrence of the sulfatase pathway in physiological settings, where the targeted uptake of steroid sulfates by specific transporters and their hydrolysis could serve to limit steroid effects to a subgroup of potentially steroid responsive cells. In humans, steroid sulfates of adrenal origin circulate in intriguingly high concentrations throughout most of life. Thus, ample substrate is available for the sulfatase pathway regardless of sex. However, the abundant adrenal output of steroid sulfates is a specific feature of select primates. Compared to humans, in our domestic mammals (dogs, cats, domestic ungulates) and laboratory rodents (mouse, rat) research into the biology of steroid sulfates is still in its infancy and information on the subject has so far been largely limited to punctual observations, which indicate considerable species-specific peculiarities. The aim of this overview is to provide a summary of the relevant information available in the above-mentioned species, predominantly taking into account data on concentrations of steroid sulfates in blood as well as the expression patterns and activities of relevant sulfotransferases and STS.

Steroid disulfates - Sulfation double trouble

Sulfation pathways have recently come into the focus of biomedical research. For steroid hormones and related compounds, sulfation represents an additional layer of regulation as sulfated steroids are more water-soluble and tend to be biologically less active. For steroid diols, an additional sulfation is possible, carried out by the same sulfotransferases that catalyze the first sulfation step. The steroid disulfates that are formed are the focus of this review. We discuss both their biochemical production as well as their putative biological function. Steroid disulfates have also been linked to various clinical conditions in numerous untargeted metabolomics studies. New analytical techniques exploring the biosynthetic routes of steroid disulfates have led to novel insights, changing our understanding of sulfation in human biology. They promise a bright future for research into sulfation pathways, hopefully too for the diagnosis and treatment of several associated diseases.

Do Dehydroepiandrosterone (DHEA) and Its Sulfate (DHEAS) Play a Role in the Stress Response in Domestic Animals?

In animal husbandry, stress is often associated with poor health and welfare. Stress occurs when a physiological control system detects a state of real or presumptive threat to the animal's homeostasis or a failure to control a fitness-critical variable. The definition of stress has mostly relied on glucocorticoids measurement, even though glucocorticoids represent one stress-response system, the hypothalamus-pituitary-adrenocortical axis, which is not precise enough as it is also related to metabolic regulation and activated in non-stressful situations (pleasure, excitement, and arousal). The mammal adrenal can synthesize the androgenic steroid dehydroepiandrosterone (DHEA) and its sulfate metabolite (DHEAS), which have been associated to the stress response in several studies performed mostly in humans and laboratory animals. Although the functions of these steroids are not fully understood, available data suggest their antagonistic effects on glucocorticoids and, in humans, their secretion is affected by stress. This review explores the scientific literature on DHEA and DHEAS release in domestic animals in response to stressors of different nature (inflammatory, physical, or social) and duration, and the extra-adrenal contribution to circulating DHEA. Then, the potential use of DHEA in conjunction with cortisol to improve the definition of the stress phenotype in farmed animals is discussed. Although the focus of this review is on farmed animals, examples from other species are reported when available.