Clinical spectrum of human STAR variants and their genotype-phenotype correlation.

Biallelic variants of steroidogenic acute regulatory protein (STAR/STARD1) may cause primary adrenal insufficiency and 46,XY disorder of sex development. STAR plays a pivotal role in transporting cholesterol into mitochondria where cholesterol serves as an essential substrate for initiating steroid biosynthesis by its conversion to pregnenolone. Generally, loss-of-function mutations of STAR cause the classic form of lipoid congenital adrenal hyperplasia (LCAH) where steroidogenesis of the adrenal cortex and the gonads is severely affected. By contrast, partial activity of STAR causes a less severe phenotype, the non-classic LCAH, which is characterized by later onset and initial manifestation with isolated adrenal insufficiency only. Disease-causing STAR variants are very rare. Numerous variants of all types have been described worldwide. Prevailing variants have been reported from Japan and Korea and in some population clusters where STAR is more common. Genotype-phenotype correlation is pretty good for STAR variants. While the exact mechanisms of cholesterol transport into mitochondria for steroidogenesis are still under investigation, the important role of STAR in this process is evident by inactivating STAR variants causing LCAH. The mechanism of disease with STAR deficiency is best described by a two-hit model: the first hit relates to impaired cholesterol import into mitochondria and thus lack of substrate for all steroid hormone biosynthesis; the second hit then relates to massive cytoplasmic lipid overload (evidenced by typically enlarged and fatty adrenal glands) leading to cell death and organ destruction. This review summarizes phenotype and genotype characteristics of human STAR variants found through the ClinVar database.

Mitochondrial dysfunction results in enhanced adrenal androgen production in H295R cells.

The role of mitochondria in steroidogenesis is well established. However, the specific effects of mitochondrial dysfunction on androgen synthesis are not fully understood. In this study, we investigate the effects of various mitochondrial and metabolic inhibitors in H295R adrenal cells and perform a comprehensive analysis of steroid and metabolite profiling. We report that mitochondrial complex I inhibition by rotenone shifts cells toward anaerobic metabolism with a concomitant hyperandrogenic phenotype characterized by rapid stimulation of dehydroepiandrosterone (DHEA, 2 h) and slower accumulation of androstenedione and testosterone (24 h). Screening of metabolic inhibitors confirmed DHEA stimulation, which included mitochondrial complex III and mitochondrial pyruvate carrier inhibition. Metabolomic studies revealed truncated tricarboxylic acid cycle with an inverse correlation between citric acid and DHEA production as a common metabolic marker of hyperandrogenic inhibitors. The current study sheds light on a direct interplay between energy metabolism and androgen biosynthesis that could be further explored to identify novel molecular targets for efficient treatment of androgen excess disorders.

Adrenal Abcg1 Controls Cholesterol Flux and Steroidogenesis.

Cholesterol is the precursor of all steroids, but how cholesterol flux is controlled in steroidogenic tissues is poorly understood. The cholesterol exporter ABCG1 is an essential component of the reverse cholesterol pathway and its global inactivation results in neutral lipid redistribution to tissue macrophages. The function of ABCG1 in steroidogenic tissues, however, has not been explored. To model this, we inactivated Abcg1 in the mouse adrenal cortex, which led to an adrenal-specific increase in transcripts involved in cholesterol uptake and de novo synthesis. Abcg1 inactivation did not affect adrenal cholesterol content, zonation, or serum lipid profile. Instead, we observed a moderate increase in corticosterone production that was not recapitulated by the inactivation of the functionally similar cholesterol exporter Abca1. Altogether, our data imply that Abcg1 controls cholesterol uptake and biosynthesis and regulates glucocorticoid production in the adrenal cortex, introducing the possibility that ABCG1 variants may account for physiological or subclinical variation in stress response.

The serum steroid signature of PCOS hints at the involvement of novel pathways for excess androgen biosynthesis.

CONTEXT: Polycystic ovary syndrome (PCOS) is defined by androgen excess and ovarian dysfunction in the absence of a specific physiological diagnosis. The best clinical marker of androgen excess is hirsutism, while the best biochemical parameter is still a matter of debate. Current consensus guidelines recommend, among other hormones, serum free testosterone as an important serum parameter to measure androgen excess. Recently, however, novel active androgens and androgen metabolic pathways have been discovered. OBJECTIVE: To assess the contribution of novel androgens and related steroid biosynthetic pathways to the serum steroid pool in PCOS women in comparison to healthy controls. DESIGN: This is a case control study, wherein PCOS was diagnosed according to the AE-PCOS 2009 criteria. Serum steroid profiling was performed by liquid chromatography high-resolution mass spectrometry. SETTING: Yeditepe University and associated clinics in Istanbul, Turkey, together with Bern University Hospital Inselspital, Bern, Switzerland. PARTICIPANTS: 42 PCOS women and 42 matched, healthy control women. MAIN OUTCOME MEASURES: Assessment of 34 steroids compartmentalized in four androgen related pathways: the classic androgen pathway, the backdoor pathway, the C11-oxy backdoor pathway, and the C11-oxy (11ß-hydroxyandrostenedione) pathway. RESULTS: Metabolites of all four pathways were identified in healthy and PCOS women. Highest concentrations were found for progesterone in controls and androstenedione in PCOS. Lowest levels were found for 11-ketotestosterone in controls compared to PCOS, and for 20α-hydroxyprogesterone in PCOS compared to controls. PCOS also had higher serum testosterone levels compared to the controls. PCOS women had overall higher levels of steroid metabolites of all four androgen pathways compared to healthy controls. CONCLUSIONS: Novel alternative pathways contribute to the androgen production in healthy and PCOS women. Hyperandrogenism in PCOS is characterized by an overall increase of serum androgens in the classic, backdoor and C11-oxy pathways. While monogenetic disorders of steroid biosynthesis can be recognized by a specific pattern in the steroid profile, no diagnostic pattern or classifier was found in the serum for PCOS.

Cholesterol Deprivation Drives DHEA Biosynthesis in Human Adrenals.

Adrenarche is an early event in sexual maturation in prepubertal children and corresponds to the postnatal development of the adrenocortical zona reticularis (zR). However, the molecular mechanisms that govern the onset and maturation of zR remain unknown. Using tissue laser microdissection combined with transcript quantification and immunodetection, we showed that the human zR receives low levels of cholesterol in comparison with other adrenal layers. To model this metabolic condition, we challenged adrenal cells in vitro using cholesterol deprivation. This resulted in reprogramming the steroidogenic pathway toward inactivation of 3-beta-hydroxysteroid dehydrogenase type 2 (HSD3B2), increased CYB5A expression, and increased biosynthesis of dehydroepiandrosterone (DHEA), 3 key features of zR maturation during adrenarche. Finally, we found that cholesterol deprivation leads to decreased transcriptional activity of POU3F2, which normally stimulates the expression of HSD3B2 by directly binding to its promoter. These findings demonstrate that cholesterol deprivation can account, at least in part, for the acquisition of a zR-like androgenic program in humans.

The role of circulating miRNAs in leptin resistance in obese children.

OBJECTIVES: Leptin resistance is one of the important causes of obesity in children. Besides known causes of leptin resistance like mutations in leptin and leptin receptor genes, overexpression of SOCS3 in arcuate nucleus is a potential cause of leptin resistance. We aimed to determine the effects of circulating miRNAs on leptin resistance in obese children by targeting SOCS3 pathway. METHODS: miRNAs potentially targeting SOCS3 were determined by using online target prediction databases. Polymorphisms in miRNA target sequences were determined by using online genome browsers. miRNA expression levels of obese (n=35) and non-obese (n=30) children were determined by qPCR method, genotyping were performed by real-time PCR method and serum leptin, leptin receptor and SOCS3 levels were measured by ELISA method. RESULTS: miRNA profiling have shown that serum miR-218-5p levels are significantly (p<0.05) increased in accordance with serum leptin levels in obese children. CONCLUSIONS: In this study we used target prediction methods for evaluating potential miRNAs which may involve in development of leptin resistance. We have shown that miR-218-5p might be taking part in leptin resistance in obese children.

Potential Protective Role of SDF-1 and CXCR4 Gene Variants in the Development of Dementia.

BACKGROUND: The aim of this study was to evaluate the role of polymorphisms of stromal cell-derived factor-1 (SDF-1) and chemokine receptor-4 (CXCR4) genes in dementia susceptibility in a Turkish population. SUBJECTS AND METHODS: The study group included 61 dementia patients, while the control group comprised 82 healthy individuals. Gene polymorphisms of SDF-1 3'A G801A (rs1801157) and CXCR4 C138T (rs2228014) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. RESULTS: A significantly reduced risk for developing dementia was found for the group bearing an A allele for SDF-1 3'A polymorphism (p=0.009; χ2=6.812; OR=0.626; 95%CI= 0.429-0.913). The frequency of the CXCR4 TT and TC genotype was significantly lower in patients with dementia compared to controls (p=0.028; χ2=5.583; OR=0.215; 95%CI=0.05-0.914); (p=0.027; χ2=4.919; OR=0.484; 95% CI=0.246-0.955). Additionally, combined genotype analysis showed that the frequency of SDF1 GA-CXCR4 CC was significantly lower in patients with dementia in comparison with those of controls (p=0.049; OR=0.560; 95% CI= 0.307±1.020). CONCLUSIONS: Our study provides new evidence that SDF1 A and CXCR4 T alleles may be associated with a decreased dementia risk. The present study is important because to our knowledge, it is the first one to be conducted in a Turkish population to date, but we believe that more patients and controls are needed to obtain statistically significant results.

RRM1, RRM2 and ERCC2 Gene Polymorphisms in Coronary Artery Disease.

BACKGROUND/AIM: Coronary artery disease (CAD) is a chronic inflammatory disease seen as formation of atherosclerotic plaques (atheroma) in coronary arteries. Recent published papers show that DNA damage and repair mechanisms play a crucial role on the development and severity of atheromas. In this study, we investigated nucleotide excision repair (NER) pathway-related gene polymorphisms in atherosclerosis. XPD, encoded by ERCC2 gene, is an ATP-depended helicase enzyme involved in the NER pathway. Ribonucleotide reductase (RR) is a tetra meric enzyme, synthesizing deoxyribonucleotides from ribonucleotides for DNA synthesis. RR is encoded by the RRM1 and RRM2 genes, which are two subunits of RR enzyme. MATERIALS AND METHODS: DNA samples isolated from peripheral blood were genotyped with real-time polymerase chain reaction (RT-PCR) for RRM1 (rs12806698), RRM2(rs6859180) and ERCC2 (rs13181) genes. RESULTS: The frequency of the RRM1 AC heterozygote genotype was found to be significantly lower (odds ratio (OR)=0.369, 95% confidence interval (CI)=0.179-0.760; p=0.006), whereas the CC homozygote genotype was found to be significantly higher in patients compared to controls (OR=7.636, 95% CI=2.747-21.229; p=0.000). In addition, the RRM1 A allele was higher in control group (p=0.000, OR=0.131 95%CI=0.047-0.364). For the ERCC2 gene, GG genotype was significantly higher in control group (p=0.017, OR=0.387, 95%CI=0.175-0.152) and TT genotype (p=0.021) was higher in CAD group. TT genotype had a ~3-fold increased risk (OR=3.615, 95%CI=1.148-11.380) for CAD. Carrying T allele appears to be a risk factor for CAD (p=0.017, OR=2.586, 95%CI=1.173-5.699), while the G allele might be a risk-reducing factor (p=0.021, OR=0.277, 95%CI=0.088-0.871) for CAD. CONCLUSION: RRM1 and ERCC gene polymorphisms, having homozygous mutant genotype, might be a risk factor for CAD. RRM1 and ERCC wild type alleles are risk-reducing factor for CAD. Also, carrying RRM1 A allele might have a protective effect for smokers.

Apolipoprotein E Genotypes in Patients with Prostate Cancer.

BACKGROUND: Apolipoprotein E (ApoE) is a potential inhibitor of cell proliferation, immune regulation and modulation of cell growth and differentiation; it also has a substantial role in antioxidant activity. ApoE has a potential role in prostate cancer progression. MATERIALS AND METHODS: ApoE genotyping was performed using real-time polymerase chain reaction (RT-PCR) for blood samples from a group of patients with prostate cancer (n=68) and a control group (n=78). RESULTS: The frequency of the E3/E3 genotype was significantly higher in patients compared to controls (p=0.004). E3/E3 genotype carriers were 3.6-fold more likely to be patients than controls (odds ratio=3.67, 95% confidence interval=1.451-9.155; p=0.004). Additionally, the patients with E3/E3 genotype had significantly higher Gleason score (p=0.017), and more patients with this genotype had a Gleason score higher than 7 (p=0.007). Individuals carrying the E4 allele were significantly more common in the control group (p=0.006). The frequency of the E3/E4 genotype was found to be significantly higher in controls compared to patients (p=0.007), and patients were significantly less likely to have this genotype than controls (odds ratio=0.89, 95% confidence interval=0.833-0.967, p=0.007). Individuals carrying the E2/E3 genotype had a significantly lower Gleason score (p=0.049)-all of the patients with this genotype had a Gleason score lower than 7 (p=0.024). CONCLUSION: E3/E3 genotype may be a potential risk factor for prostate cancer and high Gleason scoring. The E4 allele maybe a risk-reducing factor for prostate cancer.

Investigation of Interleukin-1ß Polymorphisms in Prostate Cancer.

BACKGROUND: Cytokine-mediated immune and inflammatory responses are considered to play an important role in the pathogenesis of prostate cancer. The present study investigated certain interleukin-1ß (IL1ß) polymorphisms and their association with prostate cancer. MATERIALS AND METHODS: Genotyping of the IL1B-31(rs 1143627 G>A) and IL1B-511(rs 16944 A