Steroid Sulfatase Deficiency and Androgen Activation Before and After Puberty

Revisiting X-linked congenital ichthyosis

X-linked recessive ichthyosis (XLI) is a hereditary skin disease characterized by generalized dryness and scaling of the skin, with frequent extracutaneous manifestations. It is the second most common type of ichthyosis, with a prevalence of 1/6,000 to 1/2,000 in males and without any racial or geographical differences. The causative gene for XLI is the steroid sulfatase gene (STS), located on Xp22.3. STS deficiency causes an abnormal cholesterol sulfate (CS) accumulation in the stratum corneum (SC). Excess CS induces epidermal permeability barrier dysfunction and scaling abnormalities. This review summarizes XLI's genetic, clinical, and pathological features, pathogenesis, diagnosis and differential diagnoses, and therapeutic perspectives. Further understanding the role of the STS gene pathogenic variants in XLI may contribute to a more accurate and efficient clinical diagnosis of XLI and provide novel strategies for its treatment and prenatal diagnosis.

Unraveling the molecular mechanisms of cell migration impairment and apoptosis associated with steroid sulfatase deficiency: Implications for X-linked ichthyosis

Steroid sulfatase (STS) deficiency is responsible for X-linked ichthyosis (XLI), a genetic disorder characterized by rough and dry skin caused by excessive keratinization. The impaired keratinization process leads to reduced cell mobility and increased apoptosis, which can cause an excessive buildup of the stratum corneum. In this study, we investigated the mechanisms underlying XLI and found that STS deficiency reduces cell mobility and increases apoptosis in human keratinocyte HaCaT cells. To explore these mechanisms further, RNA-sequencing was conducted on skin tissues from STS transgenic and knockout mice. Our RNA-seq results revealed that STS deficiency plays a critical role in regulating multiple signaling pathways associated with cell mobility and apoptosis, such as Wnt/β signaling and the Hippo signaling pathway. Knockdown of the STS gene using shRNA in HaCaT cells led to an upregulation of E-cadherin expression and suppression of key factors involved in epithelial-mesenchymal transition (EMT), such as N-cadherin and vimentin. Inhibition of EMT involved the Hippo signaling pathway and reduction of HIF-1α. Interestingly, inhibiting STS with shRNA increased mitochondrial respiration levels, as demonstrated by the extracellular flux oxygen consumption rate. Additionally, we observed a significant increase in ROS production in partial STS knockout cells compared to control cells. Our study demonstrated that the excessive generation of ROS caused by STS deficiency induces the expression of Bax and Bak, leading to the release of cytochrome c and subsequent cell death. Consequently, STS deficiency impairs cell mobility and promotes apoptosis, offering insights into the pathophysiological processes and potential therapeutic targets for XLI.

History of Adrenal Research: From Ancient Anatomy to Contemporary Molecular Biology

The adrenal is a small, anatomically unimposing structure that escaped scientific notice until 1564 and whose existence was doubted by many until the 18th century. Adrenal functions were inferred from the adrenal insufficiency syndrome described by Addison and from the obesity and virilization that accompanied many adrenal malignancies, but early physiologists sometimes confused the roles of the cortex and medulla. Medullary epinephrine was the first hormone to be isolated (in 1901), and numerous cortical steroids were isolated between 1930 and 1949. The treatment of arthritis, Addison's disease, and congenital adrenal hyperplasia (CAH) with cortisone in the 1950s revolutionized clinical endocrinology and steroid research. Cases of CAH had been reported in the 19th century, but a defect in 21-hydroxylation in CAH was not identified until 1957. Other forms of CAH, including deficiencies of 3β-hydroxysteroid dehydrogenase, 11β-hydroxylase, and 17α-hydroxylase were defined hormonally in the 1960s. Cytochrome P450 enzymes were described in 1962-1964, and steroid 21-hydroxylation was the first biosynthetic activity associated with a P450. Understanding of the genetic and biochemical bases of these disorders advanced rapidly from 1984 to 2004. The cloning of genes for steroidogenic enzymes and related factors revealed many mutations causing known diseases and facilitated the discovery of new disorders. Genetics and cell biology have replaced steroid chemistry as the key disciplines for understanding and teaching steroidogenesis and its disorders.

Association of dehydroepiandrosterone sulfate, birth size, adiposity and cardiometabolic risk factors in 7-year-old children

BACKGROUND

Low birth size (BS) and obesity have been associated with higher dehydroepiandrosterone sulfate (DHEAS) levels in childhood, insulin acting as a mediator, despite contradictory findings. To further explore these issues, we studied the associations between DHEAS, BS, adiposity, maternal characteristics, and cardiometabolic risk indicators, in participants of Generation XXI, a population-based birth cohort.

METHODS

A sample of 700 children (mean age 7.1 yr) was randomly selected. Data on maternal characteristics, BS, body mass index (BMI), waist-to-height ratio, body fat (dual-energy X-ray absorptiometry), insulin, lipid profile, and high-sensitivity C-reactive protein were analyzed in relation to DHEAS.

RESULTS

DHEAS was negatively associated with BS and positively associated with all adiposity indicators, with no sex differences. DHEAS was positively associated with insulinemia independently of the child's BS or BMI. No significant association was found between DHEAS, maternal characteristics, lipid profile, or high-sensitivity C-reactive protein. Including insulin in the model did not affect the association between BS and DHEAS but reduced the magnitude of the BMI effect by 24% for boys and 30% for girls.

CONCLUSION

Higher DHEAS levels at 7 years old were associated with lower BS and higher adiposity. DHEAS levels were positively associated with insulinemia independently of BS or BMI.

IMPACT

Low birth weight and obesity have been associated with higher dehydroepiandrosterone sulfate (DHEAS) levels in prepuberty. Insulin has been suggested as a mediator, despite previous studies failing to show an association between DHEAS and insulin levels. In a randomly selected population of 700 7-year-old children from the Generation XXI birth cohort, higher DHEAS levels were associated with a lower birth size and higher adiposity, with no sex differences. DHEAS was positively related to insulinemia independently of the child's birth size or body mass index. No association was found between DHEAS and other cardiometabolic risk factors.

Sex-linked genetic mechanisms and atrial fibrillation risk

Atrial fibrillation (AF) is a cardiac condition characterised by an irregular heartbeat, atrial pathology and an elevated downstream risk of thrombosis and heart failure, as well as neurological sequelae including stroke and dementia. The prevalence and presentation of, risk factors for, and therapeutic responses to, AF differ by sex, and this sex bias may be partially explained in terms of genetics. Here, we consider four sex-linked genetic mechanisms that may influence sex-biased phenotypes related to AF and provide examples of each: X-linked gene dosage, X-linked genomic imprinting, sex-biased autosomal gene expression, and male-limited Y-linked gene expression. We highlight novel candidate risk genes and pathways that warrant further investigation in clinical and preclinical studies. Understanding the biological basis of sex differences in AF should allow better prediction of disease risk, identification of novel risk/protective factors, and the development of more effective sex-tailored interventions.

Steroid Sulfation in Adrenal Tumors

CONTEXT

The adrenal cortex produces specific steroid hormones including steroid sulfates such as dehydroepiandrosterone sulfate (DHEAS), the most abundant steroid hormone in the human circulation. Steroid sulfation involves a multistep enzyme machinery that may be impaired by inborn errors of steroid metabolism. Emerging data suggest a role of steroid sulfates in the pathophysiology of adrenal tumors and as potential biomarkers.

EVIDENCE ACQUISITION

Selective literature search using "steroid," "sulfat*," "adrenal," "transport," "mass spectrometry" and related terms in different combinations.

EVIDENCE SYNTHESIS

A recent study highlighted the tissue abundance of estrogen sulfates to be of prognostic impact in adrenocortical carcinoma tissue samples using matrix-assisted laser desorption ionization mass spectrometry imaging. General mechanisms of sulfate uptake, activation, and transfer to substrate steroids are reasonably well understood. Key aspects of this pathway, however, have not been investigated in detail in the adrenal; these include the regulation of substrate specificity and the secretion of sulfated steroids. Both for the adrenal and targeted peripheral tissues, steroid sulfates may have relevant biological actions beyond their cognate nuclear receptors after desulfation. Impaired steroid sulfation such as low DHEAS in Cushing adenomas is of diagnostic utility, but more comprehensive studies are lacking. In bioanalytics, the requirement of deconjugation for gas-chromatography/mass-spectrometry has precluded the study of steroid sulfates for a long time. This limitation may be overcome by liquid chromatography/tandem mass spectrometry.

CONCLUSIONS

A role of steroid sulfation in the pathophysiology of adrenal tumors has been suggested and a diagnostic utility of steroid sulfates as biomarkers is likely. Recent analytical developments may target sulfated steroids specifically.

Normal and Premature Adrenarche

Adrenarche is the maturational increase in adrenal androgen production that normally begins in early childhood. It results from changes in the secretory response to adrenocorticotropin (ACTH) that are best indexed by dehydroepiandrosterone sulfate (DHEAS) rise. These changes are related to the development of the zona reticularis (ZR) and its unique gene/enzyme expression pattern of low 3ß-hydroxysteroid dehydrogenase type 2 with high cytochrome b5A, sulfotransferase 2A1, and 17ß-hydroxysteroid dehydrogenase type 5. Recently 11-ketotestosterone was identified as an important bioactive adrenarchal androgen. Birth weight, body growth, obesity, and prolactin are related to ZR development. Adrenarchal androgens normally contribute to the onset of sexual pubic hair (pubarche) and sebaceous and apocrine gland development. Premature adrenarche causes ≥90% of premature pubarche (PP). Its cause is unknown. Affected children have a significantly increased growth rate with proportionate bone age advancement that typically does not compromise growth potential. Serum DHEAS and testosterone levels increase to levels normal for early female puberty. It is associated with mildly increased risks for obesity, insulin resistance, and possibly mood disorder and polycystic ovary syndrome. Between 5% and 10% of PP is due to virilizing disorders, which are usually characterized by more rapid advancement of pubarche and compromise of adult height potential than premature adrenarche. Most cases are due to nonclassic congenital adrenal hyperplasia. Algorithms are presented for the differential diagnosis of PP. This review highlights recent advances in molecular genetic and developmental biologic understanding of ZR development and insights into adrenarche emanating from mass spectrometric steroid assays.

Steroid sulfatase deficiency causes cellular senescence and abnormal differentiation by inducing Yippee-like 3 expression in human keratinocytes

Human steroid sulfatase (STS) is an enzyme that catalyzes the hydrolysis of dehydroepiandrosterone sulfate (DHEAS), estrone sulfate (E1S), and cholesterol sulfate. Abnormal expression of STS causes several diseases including colorectal, breast, and prostate cancer and refractory skin disease. In particular, accumulation of intracellular cholesterol sulfate by STS deficiency leads to a skin disorder with abnormal keratinization called X-linked ichthyosis (XLI). To determine the detailed mechanisms of XLI, we performed RNA sequencing (RNA-seq) analysis using human keratinocyte HaCaT cells treated with cholesterol and cholesterol sulfate. Of the genes with expression changes greater than 1.5-fold, Yippee-like 3 (YPEL3), a factor expected to affect cell differentiation, was found. Induction of YPEL3 causes permanent growth arrest, cellular senescence, and inhibition of metastasis in normal and tumor cells. In this study, we demonstrate that YPEL3 expression was induced by STS deficiency and, using the CRISPR/Cas9 system, a partial knock-out (STS^+/−) cell line was constructed to establish a disease model for XLI studies. Furthermore, we show that increased expression of YPEL3 in STS-deficient cell lines promoted cellular senescence and expression of keratinization-related proteins such as involucrin and loricrin. Our results suggest that upregulation of YPEL3 expression by STS deficiency may play a crucial role in inducing cellular senescence and abnormal differentiation in human keratinocytes.

Steroid sulfatase inhibitors: the current landscape

Introduction: Steroid sulfatase (STS) enzyme is responsible for transforming the inactive sulfate metabolites of steroid sex hormones into the active free steroids. Both the deficiency and the over-expression of STS are associated with the pathophysiology of certain diseases. This article provides the readership with a comprehensive review about STS enzyme and its recently reported inhibitors.Areas covered: In the present article, we reviewed the structure, location, and substrates of STS enzyme, physiological functions of STS, and disease states related to over-expression or deficiency of STS enzyme. STS inhibitors reported during the last five years (2016-present) have been reviewed as well.Expert opinion: Irosustat is the most successful STS inhibitor drug candidate so far. It is currently under investigation in clinical trials for treatment of estrogen-dependent breast cancer. Non-steroidal sulfamate is the most favorable scaffold for STS inhibitor design. They can be beneficial for the treatment of hormone-dependent cancers and neurodegenerative disorders without significant estrogenic side effects. Moreover, dual-acting molecules (inhibitors of STS + another synergistic mechanism) can be therapeutically efficient.

Very High Dehydroepiandrosterone Sulfate (DHEAS) in Serum of an Overweight Female Adolescent Without a Tumor

Introduction: An increase of serum dehydroepiandrosterone (DHEA) sulfate (DHEAS) is observed in premature adrenarche and congenital adrenal hyperplasia. Very high DHEAS levels are typical for adrenal tumors. Approximately 74% of DHEAS is hydrolyzed to DHEA by the steroid sulfatase (STS). The reverse reaction is DHEA sulfation. Besides these two enzyme reactions, the DHEAS transported through the cell membrane is important for its distribution and excretion. Case Presentation: We present a female adolescent with overweight and a very high DHEAS. The presence of a DHEAS-producing tumor was rejected using ultrasonography, Magnetic Resonance Tomography (MRT), and dexamethasone suppression. STS deficiency was suspected. Sequence analysis revealed a heterozygous nonsense mutation which predicts a truncation of the carboxyl region of the STS that is implicated in substrate binding. No partial gene deletion outside exon 5 was detected by multiplex ligation-dependent probe amplification. The bioassay revealed normal enzyme activity in the patient's leukocytes. A defect of transporter proteins was suggested. Both efflux [multidrug-resistance protein (MRP)2 and breast cancer-resistance protein (BCRP)] and uptake [organic anion-transporting polypeptide (OATP) and organic anion transporter (OAT) carriers] transporters were studied. Sequence analysis of exons revealed a heterozygous Q141K variant for BCRP. Conclusions: A novel heterozygous nonsense mutation in the STS gene and a known heterozygous missense variant in the BCRP gene were found. The heterozygous nonsense mutation in the STS gene is not supposed to be responsible for STS deficiency. The BCRP variant is associated with reduced efflux transport activity only in its homozygous state. The combination of the two heterozygous mutations could possibly explain the observed high levels of DHEAS and other sulfated steroids.

Association between mercury in cord serum and sex-specific DNA methylation in cord tissues

Prenatal exposure to mercury in utero causes abnormal foetal growth and adverse outcomes. DNA methylation is currently considered a possible mechanism through which this occurs. However, few studies have investigated the association between prenatal exposure to mercury and DNA methylation in detail. This study aimed to clarify the relationship between prenatal exposure to total mercury (Hg) and DNA methylation and its associations with sex-specific characteristics in male and female offspring. In a birth cohort study known as the Chiba study of Mother and Child Health, the DNA methylation status in cord tissue and Hg concentrations in cord serum were examined. A total of 67 participants (27 males and 40 females) were analysed based on Spearman's correlations, adjusted by a false discovery rate of the sex of each offspring. Only one methylated locus was positively correlated with Hg concentrations in cord serum in male offspring, but not in female offspring, and was annotated to the haloacid dehalogenase-like hydrolase domain-containing protein 1 (HDHD1) gene on chromosome X. This locus was located in the intron of the HDHD1 gene body and is a binding site for the zinc finger protein CCCTC-binding factor. One of the other loci, located in HDHD1, was highly methylated in the group with higher mercury concentrations, and this locus was in the gene body of HDHD1. Our results suggest that prenatal exposure to Hg might affect the epigenetic status of male foetuses.

Medical and neurobehavioural phenotypes in carriers of X-linked ichthyosis-associated genetic deletions in the UK Biobank

BACKGROUND

X-linked ichthyosis (XLI) is an uncommon dermatological condition resulting from a deficiency of the enzyme steroid sulfatase (STS), often caused by X-linked deletions spanning STS. Some medical comorbidities have been identified in XLI cases, but small samples of relatively young patients has limited this. STS is highly expressed in subcortical brain structures, and males with XLI and female deletion carriers appear at increased risk of developmental/mood disorders and associated traits; the neurocognitive basis of these findings has not been examined.

METHODS

Using the UK Biobank resource, comprising participants aged 40-69 years recruited from the general UK population, we compared multiple medical/neurobehavioural phenotypes in males (n=86) and females (n=312) carrying genetic deletions spanning STS (0.8-2.5 Mb) (cases) to male (n=190 577) and female (n=227 862) non-carrier controls.

RESULTS

We identified an elevated rate of atrial fibrillation/flutter in male deletion carriers (10.5% vs 2.7% in male controls, Benjamini-Hochberg corrected p=0.009), and increased rates of mental distress (p=0.003), irritability (p<0.001) and depressive-anxiety traits (p<0.05) in male deletion carriers relative to male controls completing the Mental Health Questionnaire. While academic attainment was unaffected, male and female deletion carriers exhibited impaired performance on the Fluid Intelligence Test (Cohen's d≤0.05, corrected p<0.1). Neuroanatomical analysis in female deletion carriers indicated reduced right putamen and left nucleus accumbens volumes (Cohen's d≤0.26, corrected p<0.1).

CONCLUSION

Adult males with XLI disease-causing deletions are apparently at increased risk of cardiac arrhythmias and self-reported mood problems; altered basal ganglia structure may underlie altered function and XLI-associated psychiatric/behavioural phenotypes. These results provide information for genetic counselling of deletion-carrying individuals and reinforce the need for multidisciplinary medical care.

Steroid Metabolome Analysis in Disorders of Adrenal Steroid Biosynthesis and Metabolism

Steroid biosynthesis and metabolism are reflected by the serum steroid metabolome and, in even more detail, by the 24-hour urine steroid metabolome, which can provide unique insights into alterations of steroid flow and output indicative of underlying conditions. Mass spectrometry-based steroid metabolome profiling has allowed for the identification of unique multisteroid signatures associated with disorders of steroid biosynthesis and metabolism that can be used for personalized approaches to diagnosis, differential diagnosis, and prognostic prediction. Additionally, steroid metabolome analysis has been used successfully as a discovery tool, for the identification of novel steroidogenic disorders and pathways as well as revealing insights into the pathophysiology of adrenal disease. Increased availability and technological advances in mass spectrometry-based methodologies have refocused attention on steroid metabolome profiling and facilitated the development of high-throughput steroid profiling methods soon to reach clinical practice. Furthermore, steroid metabolomics, the combination of mass spectrometry-based steroid analysis with machine learning-based approaches, has facilitated the development of powerful customized diagnostic approaches. In this review, we provide a comprehensive up-to-date overview of the utility of steroid metabolome analysis for the diagnosis and management of inborn disorders of steroidogenesis and autonomous adrenal steroid excess in the context of adrenal tumors.

Sulfation pathways from red to green

Sulfur is present in the amino acids cysteine and methionine and in a large range of essential coenzymes and cofactors and is therefore essential for all organisms. It is also a constituent of sulfate esters in proteins, carbohydrates, and numerous cellular metabolites. The sulfation and desulfation reactions modifying a variety of different substrates are commonly known as sulfation pathways. Although relatively little is known about the function of most sulfated metabolites, the synthesis of activated sulfate used in sulfation pathways is essential in both animal and plant kingdoms. In humans, mutations in the genes encoding the sulfation pathway enzymes underlie a number of developmental aberrations, and in flies and worms, their loss-of-function is fatal. In plants, a lower capacity for synthesizing activated sulfate for sulfation reactions results in dwarfism, and a complete loss of activated sulfate synthesis is also lethal. Here, we review the similarities and differences in sulfation pathways and associated processes in animals and plants, and we point out how they diverge from bacteria and yeast. We highlight the open questions concerning localization, regulation, and importance of sulfation pathways in both kingdoms and the ways in which findings from these "red" and "green" experimental systems may help reciprocally address questions specific to each of the systems.

Higher steroid sulfation is linked to successful weight loss in obese children

Objective Little information is available on the steroid sulfates profile in obese children. Therefore, we examined whether sulfated steroids are linked with weight status and associated comorbidities in obese children. Methods We analyzed 66 obese children (mean age 10.5 ± 2.5 years, 57.6% female, 53.9% prepubertal, mean BMI 27.0 ± 4.6 kg/m2, 50% with BMI-SDS reduction >0.5, 50% without BMI-SDS reduction) who participated in an outpatient 1-year intervention program based on exercise, behavior and nutrition therapy. We measured intact sulfated steroids (cholesterol sulfate (CS), pregnenolone sulfate (PregS), 17αOH pregnenolone sulfate (17OH-PregS), 16αOH dehydroepiandrosterone sulfate (16OH-DHEAS), DHEAS, androstenediol-3-sulfate, androsterone sulfate and epiandrosterone sulfate) by LC-MS/MS, and insulin resistance index HOMA, lipids, blood pressure at baseline and 1 year later. Results All sulfated steroids except 17OH-PregS, 16OH-DHEAS, androsterone sulfate and epiandrosterone sulfate were higher in boys compared to girls. Concentrations of CS before intervention were higher in children who lost weight. After 1 year of treatment, both groups showed increased levels of DHEAS, 16OH-DHEAS and androstenediol-3-sulfate, but PregS was only increased in children with weight loss. None of the steroid sulfates was significantly related to cardiovascular risk factors or HOMA except 17OH-PregS, which was associated with systolic blood pressure both in cross-sectional (β-coefficient: 0.09 ± 0.07, P = 0.020) and longitudinal analyses (β-coefficient: 0.06 ± 0.04, P = 0.013) in multiple linear regression analyses. Conclusions Since higher steroid sulfation capacity was associated with successful weight intervention in children disruption of sulfation may be associated with difficulties to lose weight. Future studies are necessary to prove this hypothesis.

GC/MS in Recent Years Has Defined the Normal and Clinically Disordered Steroidome: Will It Soon Be Surpassed by LC/Tandem MS in This Role?

Gas chromatography/mass spectrometry (GC/MS) has been used for steroid analysis since the 1960s. The advent of protective derivatization, capillary columns, and inexpensive electron ionization bench-top single quadrupole soon made it the method of choice for studying disorders of steroid synthesis and metabolism. However, the lengthy sample workup prevented GC/MS from becoming routine for steroid hormone measurement, which was dominated by radioimmunoassay. It was the emergence of liquid chromatography/tandem MS (LC/MS/MS) that sparked a renewed interest in GC/MS for the multicomponent analysis of steroids. GC/MS is excellent at providing an integrated picture of a person's steroid metabolome, or steroidome, as we term it. We review the recent work on newly described disorders and discuss the technical advances such as GC coupling to triple quadrupole and ion trap analyzers, two-dimensional GC/MS, and alternative ionization and detection systems such as atmospheric pressure chemical ionization (APCI) and time of flight. We believe that no novel GC/MS-based technique has the power of GC(electron ionization)/MS/MS as a "discovery tool," although APCI might provide ultimate sensitivity, which might be required in tissue steroidomics. Finally, we discuss the role of LC/MS/MS in steroidomics. This remains a challenge but offers shorter analysis times and advantages in the detection and discovery of steroids with a known structure. We describe recent advances in LC/MS steroidomics of hydrolyzed and intact steroid conjugates and suggest the technique is catching up with GC/MS in this area. However, in the end, both techniques will likely remain complementary and both should be available in advanced analytical laboratories.

SULFATION PATHWAYS: The steroid sulfate axis and its relationship to maternal behaviour and mental health

Steroid hormones can exist in functionally dissociable sulfated and non-sulfated (free) forms and can exert profound effects on numerous aspects of mammalian physiology; the ratio of free-to-sulfated steroids is governed by the antagonistic actions of steroid sulfatase (STS) and sulfotransferase (SULT) enzymes. Here, I examine evidence from human and animal model studies, which suggests that STS and its major substrate (dehydroepiandrosterone sulfate, DHEAS) and product (DHEA) can influence brain function, behaviour and mental health, before summarising how the activity of this axis varies throughout mammalian pregnancy and the postpartum period. I then consider how the steroid sulfate axis might impact upon normal maternal behaviour and how its dysfunction might contribute towards risk of postpartum psychiatric illness. Understanding the biological substrates underlying normal and abnormal maternal behaviour will be important for maximising the wellbeing of new mothers and their offspring.

SULFATION PATHWAYS: Insights into steroid sulfation and desulfation pathways

Sulfation and desulfation pathways represent highly dynamic ways of shuttling, repressing and re-activating steroid hormones, thus controlling their immense biological potency at the very heart of endocrinology. This theme currently experiences growing research interest from various sides, including, but not limited to, novel insights about phospho-adenosine-5'-phosphosulfate synthase and sulfotransferase function and regulation, novel analytics for steroid conjugate detection and quantification. Within this review, we will also define how sulfation pathways are ripe for drug development strategies, which have translational potential to treat a number of conditions, including chronic inflammatory diseases and steroid-dependent cancers.

GC/MS in Recent Years Has Defined the Normal and Clinically Disordered Steroidome: Will It Soon Be Surpassed by LC/Tandem MS in This Role?

Gas chromatography/mass spectrometry (GC/MS) has been used for steroid analysis since the 1960s. The advent of protective derivatization, capillary columns, and inexpensive electron ionization bench-top single quadrupole soon made it the method of choice for studying disorders of steroid synthesis and metabolism. However, the lengthy sample workup prevented GC/MS from becoming routine for steroid hormone measurement, which was dominated by radioimmunoassay. It was the emergence of liquid chromatography/tandem MS (LC/MS/MS) that sparked a renewed interest in GC/MS for the multicomponent analysis of steroids. GC/MS is excellent at providing an integrated picture of a person's steroid metabolome, or steroidome, as we term it. We review the recent work on newly described disorders and discuss the technical advances such as GC coupling to triple quadrupole and ion trap analyzers, two-dimensional GC/MS, and alternative ionization and detection systems such as atmospheric pressure chemical ionization (APCI) and time of flight. We believe that no novel GC/MS-based technique has the power of GC(electron ionization)/MS/MS as a “discovery tool,” although APCI might provide ultimate sensitivity, which might be required in tissue steroidomics. Finally, we discuss the role of LC/MS/MS in steroidomics. This remains a challenge but offers shorter analysis times and advantages in the detection and discovery of steroids with a known structure. We describe recent advances in LC/MS steroidomics of hydrolyzed and intact steroid conjugates and suggest the technique is catching up with GC/MS in this area. However, in the end, both techniques will likely remain complementary and both should be available in advanced analytical laboratories.

Monogenic Disorders of Adrenal Steroidogenesis

Disorders of adrenal steroidogenesis comprise autosomal recessive conditions affecting steroidogenic enzymes of the adrenal cortex. Those are located within the 3 major branches of the steroidogenic machinery involved in the production of mineralocorticoids, glucocorticoids, and androgens. This mini review describes the principles of adrenal steroidogenesis, including the newly appreciated 11-oxygenated androgen pathway. This is followed by a description of pathophysiology, biochemistry, and clinical implications of steroidogenic disorders, including mutations affecting cholesterol import and steroid synthesis, the latter comprising both mutations affecting steroidogenic enzymes and co-factors required for efficient catalysis. A good understanding of adrenal steroidogenic pathways and their regulation is crucial as the basis for sound management of these disorders, which in the majority present in early childhood.

Intracrine androgen biosynthesis, metabolism and action revisited

Androgens play an important role in metabolic homeostasis and reproductive health in both men and women. Androgen signalling is dependent on androgen receptor activation, mostly by testosterone and 5α-dihydrotestosterone. However, the intracellular or intracrine activation of C19 androgen precursors to active androgens in peripheral target tissues of androgen action is of equal importance. Intracrine androgen synthesis is often not reflected by circulating androgens but rather by androgen metabolites and conjugates. In this review we provide an overview of human C19 steroid biosynthesis including the production of 11-oxygenated androgens, their transport in circulation and uptake into peripheral tissues. We conceptualise the mechanisms of intracrinology and review the intracrine pathways of activation and inactivation in selected human tissues. The contribution of liver and kidney as organs driving androgen inactivation and renal excretion are also highlighted. Finally, the importance of quantifying androgen metabolites and conjugates to assess intracrine androgen production is discussed.

Clinical significance of 11-oxygenated androgens

PURPOSE OF REVIEW

The adrenal gland is considered a source of weak androgens, such as dehydroepiandrosterone, dehydroepiandrosterone sulfate, and androstenedione. Emerging evidence proposes a set of 11-oxygenated 19-carbon (11oxC19) adrenal-derived steroids as clinically important androgens. Such steroids include 11β-hydroxyandrostenedione, 11-ketoandrostenedione, 11β-hydroxytestosterone, and 11-ketotestosterone. The present review will discuss the synthesis, androgenic activity, and clinical implications of the 11oxC19 steroids.

RECENT FINDINGS

The clinical relevance of the 11oxC19 steroids resides in two key characteristics: the synthesis of all 11oxC19 originates predominantly in the adrenal cortex, and 11-ketotestosterone and its 5α-reduced metabolite, 11-ketodihydrotestosterone are potent agonists of the human androgen receptor, similar to the classic androgens testosterone and dihydrotestosterone, respectively. Recent studies have demonstrated higher than normal circulating levels of 11oxC19 steroids in patients with 21-hydroxylase deficiency and in polycystic ovary syndrome. The 11oxC19 steroids are also thought to contribute to castration-resistant prostate cancer progression. In addition, the 11oxC19 steroids might have clinical implications in adrenarche and postmenopausal women.

SUMMARY

Future prospective studies are needed to establish the clinical utility of the 11oxC19 steroids for individualized patient care. Preliminary data suggest that these biomarkers hold promise to improve the evaluation and management of androgen excess disorders.

Polymorphisms of STS gene and SULT2A1 gene and neurosteroid levels in Han Chinese boys with attention-deficit/hyperactivity disorder: an exploratory investigation

This study examined the relationships among polymorphisms of the STS gene and SULT2A1 gene, dehydroepiandrosterone (DHEA) and its sulfated form (DHEA-S), and characteristics of attention-deficit/hyperactivity disorder (ADHD). We used cheek swabs to obtain the genomic DNA of 200 ADHD male probands (mean age: 8.7 years), 192 patients’ mothers and 157 patients’ fathers. Three SNPs in the STS gene (rs6639786, rs2270112, and rs17268988) and one SNP in the SULT2A1 gene (rs182420) were genotyped. Saliva samples were collected from the ADHD patients to analyze DHEA and DHEA-S levels. The behavioral symptoms were evaluated with the Swanson, Nolan, and Pelham, and Version IV Scale for ADHD (SNAP-IV), and the neuropsychological function was assessed using the Conners’ Continuous Performance Tests (CPT). We found the C allele of rs2270112 within the STS gene to be over-transmitted in males with ADHD. Polymorphisms of rs182420 within the SULT2A1 gene were not associated with ADHD. In addition, the C allele carriers of rs2270112 demonstrated significantly higher DHEA-S levels than the G allele carriers. Levels of DHEA were positively correlated with attention as measured by the CPT. These findings support a potential role in the underlying biological pathogenesis of ADHD with regard to STS polymorphisms and neurosteroid levels.

Determination of 17OHPreg and DHEAS by LC-MS/MS: Impact of Age, Sex, Pubertal Stage, and BMI on the Δ5 Steroid Pathway

BACKGROUND

Dehydroepiandrosterone sulfate (DHEAS) and 17-hydroxypregnenolone (17OHPreg) are important for understanding the Δ5 pathway (e.g., in adrenarche and obesity). Although mass spectrometry has become the state-of-the-art method for quantifying steroids, there are few comprehensive age-, sex-, and pubertal stage-specific reference ranges for children.

AIMS

To develop a sensitive and reliable ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for simultaneous quantification of DHEAS and 17OHPreg and to establish entire age-, sex- and pubertal stage-specific reference ranges in children.

METHODS

A total of 684 children, 453 (243 female, 210 male) with normal body mass index (BMI; <90th) and 231 (132 female, 99 male) obese subjects (>97th), were categorized into 11 age groups, and age- and Tanner stage (PH)-specific reference ranges were determined.

RESULTS

The limit of detection was 0.05 nmol/L for 17OHPreg and 0.5 nmol/L for DHEAS. Levels of both steroids declined after the neonatal period. Comparisons with RIA assays (Siemens, Munich, Germany) (DHEAS) and an in-house kit (17OHPreg) revealed 0.95 and 0.93, respectively, as coefficients of determination. Although DHEAS-generally higher in boys-increased continuously starting at 3 to 6 years, 17OHPreg remained largely constant. In obese patients, both were significantly elevated, also in part after alignment to Tanner stages (PH).

CONCLUSIONS

UPLC-MS/MS is sensitive and reliable for quantifying DHEAS and 17OHPreg. Our data support differential maturation of CYP17 during adrenarche with successively increasing 17,20-lyase activity but largely constant 17α-hydroxylation activity. Endocrine interpretation of 17OHPreg and DHEAS must consider differential patterns for age, sex, pubertal stage, and BMI.

Role of steroid sulfatase in steroid homeostasis and characterization of the sulfated steroid pathway: Evidence from steroid sulfatase deficiency

The impact of steroid sulfatase (STS) activity in the circulating levels of both sulfated and unconjugated steroids is only partially known. In addition, the sulfated steroid pathway, a parallel pathway to the one for unconjugated steroids, which uses the same enzymes, has never been characterized in detail before. Patients with steroid sulfatase deficiency (STSD) are unable to enzymatically convert sulfated steroids into their unconjugated forms, and are a good model to elucidate how STS affects steroid biosynthesis and to study the metabolism of sulfated steroids. We quantified unconjugated and sulfated steroids in STSD serum, and compared these results with data obtained from serum of healthy controls. Most sulfated steroids were increased in STSD. However, androstenediol-3-sulfate and epiandrosterone sulfate showed similar levels in both groups, and the concentrations of androsterone sulfate were notably lower. Hydroxylated forms of DHEAS and of pregnenolone sulfate were found to be increased in STSD, suggesting a mechanism to improve the excretion of sulfated steroids. STSD testosterone concentrations were normal, but cholesterol and DHEA were significantly decreased. Additionally, serum bile acids were three-fold higher in STSD. Correlations between concentrations of steroids in each group indicate that 17α-hydroxy-pregnenolone-3-sulfate in men is mainly biosynthesized from the precursor pregnenolone sulfate and androstenediol-3-sulfate from DHEAS. These findings confirm the coexistence of two steroidogenic pathways: one for unconjugated steroids and another one for sulfated steroids. Each pathway is responsible for the synthesis of specific steroids. The equal levels of testosterone, and the reduced level of unconjugated precursors in STSD, support that testosterone is primarily synthesized from sulfated steroids. In consequence, testosterone synthesis in STSD relies on an enzyme with sulfatase activity other than STS. This study reveals that STS is a key player of steroid biosynthesis regulating the availability of circulating cholesterol.