Pregnenolone Research Articles

LncRNA NORFA promotes the synthesis of estradiol and inhibits the apoptosis of sow ovarian granulosa cells through SF-1/CYP11A1 axis

BackgroundBiosynthesis of 17β-estradiol (E2) is a crucial ovarian function in mammals, which is essential for follicular development and pregnancy outcome. Exploring the epigenetic regulation of E2 synthesis is beneficial for maintaining ovary health and the optimal reproductive traits. NORFA is the first validated sow fertility-associated long non-coding RNA (lncRNA). However, its role on steroidogenesis is elusive. The aim of this study is to investigate the regulation and underlying mechanism of NORFA to E2 synthesis in sow granulosa cells (GCs).ResultsThrough Pearson correlation analysis and comparative detection, we found that NORFA expression was positively correlated with the levels of pregnenolone (PREG) and E2 in follicles, which also exhibited similar alteration patterns during follicular atresia. ELISA was conducted and indicated for the first time that NORFA induced the synthesis of PREG and E2 in sow GCs in a dose- and time-dependent manner. RNA-seq, GSEA and quantitative analyses results validated that CYP11A1, the coding gene of P450SCC which is the first step rate-limiting enzyme of E2 synthesis, was a positive functional target of NORFA. Mechanistically, NORFA promotes SF-1 expression by stabilizing NR5A1 mRNA through directly interacting with its 3’-UTR, and also tethers SF-1 to shuttle into nucleus. Additionally, SF-1 in the nucleus activates CYP11A1 transcription by directly binding to its promoter, which ultimately induces E2 synthesis and inhibits GC apoptosis.ConclusionOur findings highlight that NORFA, a multifunctional lncRNA, induces E2 synthesis and inhibits GC apoptosis through the SF-1/CYP11A1 axis in a ceRNA-independent manner, which provide valuable clues and potential targets for follicular atresia inhibition and female fertility improvement.

Exercise Alleviates Fluoride-Induced Learning and Memory Impairment in Mice: Role of miR-206-3p and PREG.

Fluorosis decreases the learning and memory ability in humans and animals, while exercise can reduce the risk of cognitive decline. However, the effect of exercise on learning and memory in fluoride-exposed mice is unclear. For this purpose, in this study, mice were randomly allotted into four groups (16 mice per group, half male and half female): control group (group C), fluoride group (group F, 100mg/L sodium fluoride (NaF)), exercise group (group E, treadmill exercise), and E plus F group (group EF, treadmill exercise, and 100mg/L NaF). During 6months of exposure, exercise alleviated the NaF-induced decline in memory and learning. In addition, NaF induced injuries in mitochondria and myelin sheath ultrastructure and reduced the neurons number, while exercise restored them. Metabolomics results showed that phosphatidylethanolamine, pregnenolone (PREG), and lysophosphatidic acid (LysoPA) were altered among groups C, F, and EF. Combined with previous studies, it can be suggested that PREG might be a biomarker in response to exercise-relieving fluorine neurotoxicity. The miRNA sequencing results indicated that in the differently expressed miRNAs (DEmiRNAs), miR-206-3p, miR-96-5p, and miR-144-3p were shared in groups C, F, and EF. After the QRT-PCR validation and in vitro experiments, it was proved that miR-206-3p could reduce cell death and regulate AP-1 transcription factor subunit (JunD) and histone deacetylase 4 (HDAC4) to alleviate fluoride neurotoxicity. To sum up, the current study reveals that exercise could alleviate NaF-induced neurotoxicity by targeting miR-206-3p or PREG, which will contribute to revealing the pathogenesis and therapeutic method of fluoride neurotoxicity.

Reduced urine pregnenolone concentration after clinical response in patients with depression: An open-label short-term prospective study

BackgroundIdentifying biological alterations in patients with depression, particularly those that differ between responders and non-responders, is of interest to clinical practice. Biomarker candidates involve neuroactive steroids, including pregnenolone (PREG) and allopregnanolone (ALLO). However, alterations in PREG and ALLO associated with treatment response are understudied. This study's main aim was to evaluate the effects of antidepressant treatment, clinical response, and treatment duration on PREG and ALLO in depression. Materials and MethodsIn a 4-week, open-label trial, participants were allocated randomly to the venlafaxine (n = 27) or mirtazapine (n = 30) group. Urine concentrations of PREG and ALLO were assessed through gas chromatography-mass spectrometry. Participants collected night urine between 10:30 p.m. and 8:00 a.m. Two primary outcomes were analyzed. Firstly, the effect of treatment (mirtazapine or venlafaxine), clinical response (operationalized through the Hamilton Depression Rating Scale), and time (baseline compared to 28 days) on the urine concentrations of PREG or ALLO in depression. Finally, the effect of clinical response and time on the urine concentration of PREG or ALLO, independently of the antidepressant given (mirtazapine or venlafaxine). Linear mixed models were carried out. ResultsThere was no significant difference in PREG and ALLO concentrations between baseline and 28 days in responders and non-responders when investigating the venlafaxine or the mirtazapine group. However, we found a significant reduction of urine PREG concentration after 28 days of treatment in responders who received either venlafaxine or mirtazapine (estimate = −0.56; p = 0.016; 95CI [−1.003; −0.115]; Cohen’s d = −0.61). ConclusionsOur main results indicate that responders in depression show reduced urinary PREG concentrations after 4-weeks of therapy, independently of the antidepressant used. More studies are needed to confirm these findings.

The Comprehensive Steroidome in Complete TSPO/PBR Knockout Mice under Basal Conditions.

The 18 kDa translocator protein (TSPO/PBR) is a multifunctional evolutionary highly conserved outer mitochondrial membrane protein. Decades of research has reported an obligatory role of TSPO/PBR in both mitochondrial cholesterol transport and, thus, steroid production. However, the strict dependency of steroidogenesis on TSPO/PBR has remained controversial. The aim of this study was to provide insight into the steroid profile in complete C57BL/6-Tspotm1GuWu(GuwiyangWurra)-knockout male mice (TSPO-KO) under basal conditions. The steroidome in the brain, adrenal glands, testes and plasma was measured by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). We found that steroids present in wild-type (WT) mice were also detected in TSPO-KO mice, including pregnenolone (PREG), progestogens, mineralo-glucocorticosteroids and androgens. The concentrations of PREG and most metabolites were similar between genotypes, except a significant decrease in the levels of the 5α-reduced metabolites of progesterone (PROG) in adrenal glands and plasma and of the 5α-reduced metabolites of corticosterone (B) in plasma in TSPO-KO compared to WT animals, suggesting other regulatory functions for the TSPO/PBR. The expression levels of the voltage-dependent anion-selective channel (VDAC-1), CYP11A1 and 5α-reductase were not significantly different between both groups. Thus, the complete deletion of the tspo gene in male mice does not impair de novo steroidogenesis in vivo.

White Matter Microstructure Is Associated with Serum Neuroactive Steroids and Psychological Functioning.

Military service members are at increased risk for mental health issues, and comorbidity with mild traumatic brain injury (mTBI) is common. Largely overlapping symptoms between conditions suggest a shared pathophysiology. The present work investigates the associations among white matter microstructure, psychological functioning, and serum neuroactive steroids that are part of the stress-response system. Diffusion-weighted brain imaging was acquired from 163 participants (with and without military affiliation) and free-water-corrected fractional anisotropy (FAT) was extracted. Associations between serum neurosteroid levels of allopregnanolone (ALLO) and pregnenolone (PREGNE), psychological functioning, and whole-brain white matter microstructure were assessed using regression models. Moderation models tested the effect of mTBI and comorbid post-traumatic stress disorder (PTSD) and mTBI on these associations. ALLO is associated with whole-brain white matter FAT (β = 0.24, t = 3.05, p = 0.006). This association is significantly modulated by PTSD+mTBI comorbidity (β = 0.00, t = 2.50, p = 0.027), although an mTBI diagnosis alone did not significantly impact this association (p = 0.088). There was no significant association between PREGNE and FAT (p = 0.380). Importantly, lower FAT is associated with poor psychological functioning (β = -0.19, t = -2.35, p = 0.020). This study provides novel insight into a potential common pathophysiological mechanism of neurosteroid dysregulation underlying the high risk for mental health issues in military service members. Further, comorbidity of PTSD and mTBI may bring the compensatory effects of the brain's stress response to their limit. Future research is needed to investigate whether neurosteroid regulation may be a promising tool for restoring brain health and improving psychological functioning.

Alleviating effects of selenium on fluoride-induced testosterone synthesis disorder and reproduction toxicity in rats

Fluoride (F) exists widely in food, water and other natural resources, and can cause damage to the reproductive system of human and animals. Studies have shown that selenium (Se) is a necessary trace element to maintain the normal male reproductive system. However, it is not clear whether it can alleviate the damage of reproductive system induced by F. Hence, sodium fluoride (NaF) was administered singly in drinking water at 100 mg L−1 alone and co-administered by drinking with sodium selenite (Na2SeO3) at 0.5, 1.0, 2.0 mg L−1 for 10 consecutive weeks. The results demonstrated that the sperm deformity rate were increased significantly by F, however, it was improved significantly after the addition of 2.0 mg L−1 Na2SeO3. The contents of glutathione peroxidase 4 (GPX-4), selenoprotein P (SePP), pregnenolone (PREG), androstenedione (ASD), and testosterone (T) were reduced obviously in the F group, however, it was increased significantly after adding 0.5, 1.0 and 2.0 mg L−1 Na2SeO3. F decreased noticeably the mRNA and protein expression levels of steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side chain lyase (P450scc), 3β-hydroxysteroid dehydrogenase (3β-HSD), cytochrome P450 17α-hydroxylase (P450c17) and 17β-hydroxysteroid dehydrogenase (17β-HSD), which was increased obviously after the addition of 1.0 and 2.0 mg L−1 Na2SeO3. In summary, 2.0 mg L−1 Na2SeO3 can alleviate testosterone synthesis disorder induced by F via reducing oxidative stress, increasing the level of selenoprotein in testis and regulating the content of related hormones and enzyme activity during testosterone synthesis pathway.

Development and validation of a quantitative proton NMR method for the analysis of pregnenolone

Pregnenolone (PREG) is an endogenous steroid frequently sold as an over-the-counter dietary supplement touted to promote neurological and immunological health. While the PREG dietary supplement is added to the diet for health benefits, there are no FDA approved PREG drugs. However, compounded PREG drug products are available to U.S. patients. The FDA works with state regulatory authorities on the oversight of compounding activities, including developing 503A and 503B lists of bulk substances that compounders are permitted to use. PREG is one of the substances publicly nominated to be included on the 503B list. Compounded hormone therapies such as those using PREG are of interest given the lack of standardization in compounded drug products which may increase the possibility of underdosing, overdosing, or contamination. However, no USP monograph currently exists to evaluate the quality of PREG drug substance or product. To address knowledge gaps and assist in quality control, a simple and rapid quantitative proton nuclear magnetic resonance spectroscopy (qNMR) method for the identification and assay of PREG in different types of PREG products was developed and validated. PREG samples were characterized using 1D 1H and 2D 1H–13C HSQC NMR spectra. The qNMR assay method (taking approximately 10 min per NMR spectrum) was validated for precision, accuracy, specificity, robustness and linearity per ICH Q2(R1) guidance. The method was validated in a range from 0.032 to 3.2 mg/mL. As a proof of concept, seven PREG bulk substance samples, three tablet and two capsule PREG dietary supplements were assessed by the qNMR analytical procedure. NMR data from all tested samples met the expected criteria for identification and assay. The results demonstrate the potential of qNMR for the quality assessment of different types of PREG samples.

Do neurosteroids have impact on depression and cognitive functions in cases with acromegaly?

ObjectiveNeurosteroids (NSs) are a distinct hormone group and, they are known for their contribution into the status of mood and cognitive functions. Whether they are also involved in the mood disturbances and cognition in acromegaly is not known. Herein we aimed to evaluate the relation of mood status and cognitive functions with the NS levels in cases with acromegaly. DesignA total of 33 cases with acromegaly composed the acromegaly group (AG) and, 30 age and gender-matched cases without acromegaly composed the control group (CG). The levels of Allopregnanolone (AP), pregnenolone (PRG), 24S-hydroxycholesterol (24OHC), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androsterone (ADT), GH and IGF-1 were measured in each group. Beck Depression Inventory (BDI) was used to assess depressive symptoms, whereas an extensive neuropsychological assessment with several neurocognitive tests were carried out for each subject by an experienced psychologist. ResultsCases with acromegaly had lower 24OHC and DHEA levels (p = 0.002 and p = 0.007, respectively) in comparison to CG. Of the cognitive functions time to complete 1 s Series was significantly higher and, the scores on Switching Verbal Fluency Test, Boston Naming Test (BNT)-semantic and BNT-phonological, the highest learning point of Oktem Verbal Memory Processes Test (VMPT) were significantly lower in cases with acromegaly in comparison to those in controls (p = 0.004, p = 0.01, p < 0.001, p = 0.02 and p = 0.05, respectively). KAS-perseveration errors were higher in CG (p = 0.03). In AG the levels of AP were negatively correlated with the scores on Months backward Test (MBT), Animal Naming Test, Construction, BNT-spontaneous and positively correlated with BNT-incorrect answers; PRG was positively correlated with VMPT-retention scores, ADT was negatively correlated with MBT and 3 s Series scores, DHEAS was positively correlated with VMPT-the highest learning point whereas it was negatively correlated with MBT scores. Additionally, the scores on BDI were positively correlated with DHEA levels in AG. ConclusionCognitive changes may be encountered in acromegaly and, neurosteroids may contribute to the changes in certain cognitive functions.

Gut Steroids and Microbiota: Effect of Gonadectomy and Sex.

Sex steroids, derived mainly from gonads, can shape microbiota composition; however, the impact of gonadectomy and sex on steroid production in the gut (i.e., gut steroids), and its interaction with microbiota composition, needs to be clarified. In this study, steroid environment and gut steroidogenesis were analysed by liquid chromatography tandem mass spectrometry and expression analyses. Gut microbiota composition as branched- and short-chain fatty acids were determined by 16S rRNA gene sequence analysis and gas chromatography flame ionisation detection, respectively. Here, we first demonstrated that levels of pregnenolone (PREG), progesterone (PROG), and isoallopregnanolone (ISOALLO) were higher in the female rat colon, whereas the level of testosterone (T) was higher in males. Sexual dimorphism on gut steroidogenesis is also reported after gonadectomy. Sex, and more significantly, gonadectomy, affects microbiota composition. We noted that a number of taxa and inferred metabolic pathways were associated with gut steroids, such as positive associations between Blautia with T, dihydroprogesterone (DHP), and allopregnanolone (ALLO), whereas negative associations were noted between Roseburia and T, ALLO, PREG, ISOALLO, DHP, and PROG. In conclusion, this study highlights the novel sex-specific association between microbiota and gut steroids with possible relevance for the gut-brain axis.

Importance of Asparagine 202 in Manipulating Active Site Structure and Substrate Preference for Human CYP17A1.

The multifunctional cytochrome P450 17A1 (CYP17A1) plays a crucial role in human steroid hormone synthesis (UniProtKB─P05093). It first carries out standard monooxygenase chemistry, converting pregnenolone (PREG) and progesterone (PROG) into 17OH-PREG and 17OH-PROG, utilizing a "Compound I" to initiate hydrogen abstraction and radical recombination in the classic "oxygen rebound" mechanism. Additionally, these hydroxylated products also serve as substrates in a second oxidative cycle which cleaves the 17-20 carbon-carbon bond to form dehydroepiandrosterone and androstenedione, which are key precursors in the generation of powerful androgens and estrogens. Interestingly, in humans, with 17OH-PREG, this so-called lyase reaction is more efficient than with 17OH-PROG, based on Kcat/Km values. In the present work, the asparagine residue at 202 position was replaced by serine, an alteration which can affect substrate orientation and control substrate preference for the lyase reaction. First, we report studies of solvent isotope effects for the N202S CYP17A1 mutant in the presence of 17OH-PREG and 17OH-PROG, which suggest that the ferric peroxo species is the predominant catalytically active intermediate in the lyase step. This conclusion is further supported by employing a combination of cryoradiolysis and resonance Raman techniques to successfully trap and structurally characterize the key reaction intermediates, including the peroxo, the hydroperoxo, and the crucial peroxo-hemiketal intermediate. Collectively, these studies show that the mutation causes active site structural changes that alter the H-bonding interactions with the key Fe-O-O fragment and the degree of protonation of the reactive ferric peroxo intermediate, thereby impacting lyase efficiency.

Response of Sex Steroid Hormone Synthesis Substrates in Serum and Testes of Male Tilapia (Oreochromis niloticus) Exposed to Methomyl and Its Recovery Pattern

The response of synthetic substrates of sex steroid hormones—cholesterol (CHO), pregnenolone (PREG), and progesterone (PROG)—in the serum and testes of male tilapia (Oreochromis niloticus) to the environmental estrogen pesticide methomyl (0.2, 2, 20, and 200 μg·L−1) was evaluated using static-water contact toxicity tests. The results showed that low methomyl concentrations (0.2 and 2 μg·L−1) had no significant effects on the contents of CHO, PREG, and PROG in the serum and testes of male tilapia (p &gt; 0.05). Consequently, the concentration of 2 μg·L−1 could be used as a preliminary reference threshold for the non-effective dose of methomyl in male tilapia. Exposure to high methomyl concentrations (20 and 200 μg·L−1) significantly inhibited the levels of CHO, PREG, and PROG in the serum and testes of male tilapia (p &lt; 0.05) and showed a dose–response relationship. Sex steroid hormone synthesis substrate damage to male tilapia caused by less than 20 μg·L−1 methomyl was reversible, while the damage caused by equal to or greater than 200 μg·L−1 methomyl was irreversible when tilapia were transferred to methomyl-free water for 18 days. Thus, a concentration of 200 μg·L−1 could be used as a reference threshold for irreversible damage caused by methomyl in male tilapia.

Mechanism of the Clinically Relevant E305G Mutation in Human P450 CYP17A1.

Steroid metabolism in humans originates from cholesterol and involves several enzyme reactions including dehydrogenation, hydroxylation, and carbon-carbon bond cleavage that occur at regio- and stereo-specific points in the four-membered ring structure. Cytochrome P450s occur at critical junctions that control the production of the male sex hormones (androgens), the female hormones (estrogens) as well as the mineralocorticoids and glucocorticoids. An important branch point in human androgen production is catalyzed by cytochrome P450 CYP17A1 and involves an initial Compound I-mediated hydroxylation at the 17-position of either progesterone (PROG) or pregnenolone (PREG) to form 17-hydroxy derivatives, 17OH-PROG and 17OH-PREG, with approximately similar efficiencies. Subsequent processing of the 17-hydroxy substrates involves a C17-C20 bond scission (lyase) activity that is heavily favored for 17OH-PREG in humans. The mechanism for this lyase reaction has been debated for several decades, some workers favoring a Compound I-mediated process, with others arguing that a ferric peroxo- is the active oxidant. Mutations in CYP17A1 can have profound clinical manifestations. For example, the replacement of the glutamic acid side with a glycine chain at position 305 in the CYP17A1 structure causes a clinically relevant steroidopathy; E305G CYP17A1 displays a dramatic decrease in the production of dehydroepiandrosterone from pregnenolone but surprisingly increases the activity of the enzyme toward the formation of androstenedione from progesterone. To better understand the functional consequences of this mutation, we self-assembled wild-type and the E305G mutant of CYP17A1 into nanodiscs and examined the detailed catalytic mechanism. We measured substrate binding, spin state conversion, and solvent isotope effects in the hydroxylation and lyase pathways for these substrates. Given that, following electron transfer, the ferric peroxo- species is the common intermediate for both mechanisms, we used resonance Raman spectroscopy to monitor the positioning of important hydrogen-bonding interactions of the 17-OH group with the heme-bound peroxide. We discovered that the E305G mutation changes the orientation of the lyase substrate in the active site, which alters a critical hydrogen bonding of the 17-alcohol to the iron-bound peroxide. The observed switch in substrate specificity of the enzyme is consistent with this result if the hydrogen bonding to the proximal peroxo oxygen is necessary for a proposed nucleophilic peroxoanion-mediated mechanism for CYP17A1 in carbon-carbon bond scission.

Dehydroepiandrosterone sulfate, dehydroepiandrosterone, 5α-dihydroprogesterone and pregnenolone in women with migraine: Analysis of serum levels and correlation with age, migraine years and frequency

Migraine is a very painful, disabling and extremely common disorder among the world's adult population, especially women, and it is associated with a variety of comorbidities. Neuroactive steroids exhibit pleiotropic actions on the nervous system. Alterations in their peripheral and central levels could be involved in the pathogenesis, still not fully understood, of migraine and its comorbidities. The purpose of our exploratory study was to determine and compare the serum levels of dehydroepiandrosterone sulfate (DHEAS), dehydroepiandrosterone (DHEA), 5α-dihydroprogesterone (DHP) and pregnenolone (PREGNE) between women suffering from migraine without aura (MO group, n = 30) and age-matched non-headache women as controls (C group, n = 30). Correlations with age, migraine years and frequency were also analyzed. The patients were enrolled at a headache center; controls were patients’ contacts. Calibrators and serum samples were spiked with the internal standards (ISs) solution and treated to deplete proteins and phospholipids. The obtained extracts were evaporated to dryness, derivatized and analyzed by LC-MS/MS in multiple reaction monitoring mode. Analytes’ levels were determined by interpolation on the regression curves, generated from the analyte quantifier ion peak area to the corresponding IS. MO group presented significantly lower levels of DHEAS, DHEA and DHP compared to C group (P < 0.05, Student’t-test) and the neurosteroid levels negatively correlated with years of migraine and migraine days/3 months (P < 0.05, linear regression analysis). These results parallel to previous studies showing reduced serum levels of allopregnanolone and pregnenolone sulfate in women with migraine. The low serum levels found for both excitatory and inhibitory neurosteroids suggested that women with migraine might suffer from inadequate neuroprotection, anti-inflammation activity and pain modulation. These deficits might underlie the migraine chronification process and represent the link between migraine and its various comorbidities.

Therapeutic potential of pregnenolone and pregnenolone methyl ether on depressive and CDKL5 deficiency disorders: Focus on microtubule targeting.

Pregnenolone methyl‐ether (PME) is a synthetic derivative of the endogenous neuroactive steroid pregnenolone (PREG), which is an important modulator of several brain functions. In addition to being the precursor of steroids, PREG acts directly on various targets including microtubules (MTs), the functioning of which is fundamental for the development and homeostasis of nervous system. The coordination of MT dynamics is supported by a plethora of MT‐associated proteins (MAPs) and by a specific MT code that is defined by the post‐translational modifications of tubulin. Defects associated with MAPs or tubulin post‐translational modifications are linked to different neurological pathologies including mood and neurodevelopmental disorders. In this review, we describe the beneficial effect of PME in major depressive disorders (MDDs) and in CDKL5 deficiency disorder (CDD), two pathologies that are joint by defective MT dynamics. Growing evidence indeed suggests that PME, as well as PREG, is able to positively affect the MT‐binding of MAP2 and the plus‐end tracking protein CLIP170 that are both found to be deregulated in the above mentioned pathologies. Furthermore, PME influences the state of MT acetylation, the deregulation of which is often associated with neurological abnormalities including MDDs. By contrast to PREG, PME is not metabolised into other downstream molecules with specific biological properties, an aspect that makes this compound more suitable for therapeutic strategies. Thus, through the analysis of MDDs and CDD, this work focuses attention on the possible use of PME for neuronal pathologies associated with MT defects.

A preliminary study on the mechanism of the neurosteroid-mediated ionotropic receptor dysfunction in neurodevelopmental toxicity induced by decabromodiphenyl ether

The mechanism of neurodevelopmental toxicity of decabromodiphenyl ether (BDE209) remains unclear. Recent evidence suggests that neurosteroids disorders play a vital role in BDE209 induced-neurodevelopmental toxicity. To explore the mechanism of it, pregnant ICR mice were orally gavaged with 0, 225, and 900 mg kg−1 BDE209 for about 42 days. Spatial learning and memory abilities of offspring were tested on postnatal day (PND) 21. Offspring were euthanized at PND26, the neuronal structure, neurosteroids level, and related proteins including neurosteroids synthase, ionotropic receptors and cAMP-response element binding protein (CREB) pathway were evaluated, as well as Ca2+ concentration and the mitochondrial membrane potential (Mmp). Our results showed that BDE209 impaired learning and memory abilities and disrupted neuronal structure. Meanwhile, BDE209 decreased the pregnenolone (PREG), dehydroepiandrosterone (DHEA), progesterone (PROG) and allopregnanolone (ALLO) levels in the serum and brain, as well as the mRNA and protein levels of cholesterol-side-chain cleavage enzyme (P450scc), steroid 17α-hy-droxylase (P450C17), 3β-hydroxysteroid dehydrogenase (3β-HSD) and steroid 5α-reductase of type I (5α-R) in the hippocampi. Also, BDE209 suppressed mRNA and protein levels of NR1, NR2A and NR2B subunits of the N-methyl-D-aspartic acid receptor (NMDAR) and α1 subunit of the Gamma-amino butyric acid A receptor (GABAAR), but increased the levels of β2 and γ2 subunits of the GABAAR in the hippocampi. Moreover, BDE209 increased the Ca2+ concentration and phosphorylation extracellular regulated protein kinases (P-ERK) 1/2 level, but decreased the P-CREB and Mmp level in the hippocampi. These results indicate that BDE209 exposure during pregnancy and lactation is possible to affect learning and memory formation of offspring by the neurosteroid-mediated ionotropic receptors dysfunction.

Inverse association of certain seminal phthalate metabolites with semen quality may be mediated by androgen synthesis: A cross-sectional study from the South China

BackgroundSeveral in vitro and in vivo studies have demonstrated the effects of phthalates on androgen synthesis, and the adverse outcomes of phthalate exposure on male reproductive function have been reported. However, the direct relationship among these three factors remains unknown. ObjectiveTo explore the potential roles of steroids involved in androgen synthesis in the association between phthalate exposure and semen quality. MethodsEighteen phthalate metabolites (mPAEs) and nine steroids were analyzed in semen samples of 403 male participants aged 18–54 years from a hospital in Shenzhen, China. The associations across phthalate metabolites, steroids, and eleven semen quality parameters were evaluated by multivariate linear regression and logistical regression models. The potential contributions of steroids to the associations between phthalate metabolites and semen quality outcomes were explored by mediation effect analysis. ResultsIn this cross-sectional study, mono-n-butyl phthalate (MnBP) was inversely associated with nine continuous semen quality parameters in a dose-dependent manner (all p for trend < 0.05). Positive associations were observed between MnBP tertiles and androstenedione (ADD) and pregnenolone (PGL), of which only ADD was significantly associated with sperm quality (i.e., motility, p < 0.05). The estimated average mediated effects of seminal ADD on the associations between MnBP and lower sperm motility parameters (i.e., total motility, TR; progressive motility, PR; curvi-linear velocity, VCL) were 6.4–11.9% (all p < 0.05). The potential mediated effects of ADD on the increasing risks of TR (9.8%) and PR (8.5%) abnormalities induced by MnBP exposure were also observed in logistical regression analysis. ConclusionOur results indicated that androgen synthesis in reproductive system may be potentially affected by phthalate exposure, thereby resulting in reduced sperm motility in adult men. Further studies are needed to understand the actual roles and underlying mechanism of action of androstenedione on these associations.

P450 CYP17A1 Variant with a Disordered Proton Shuttle Assembly Retains Peroxo-Mediated Lyase Efficiency.

Human cytochrome P450 CYP17A1 first catalyzes hydroxylation at the C17 position of either pregnenolone (PREG) or progesterone (PROG), and a subsequent C17 -C20 bond scission to produce dehydroepiandrosterone (DHEA) or androstenedione (AD). In the T306A mutant, replacement of the Threonine 306 alcohol functionality, essential for efficient proton delivery in the hydroxylase reaction, has only a small effect on the lyase activity. In this work, resonance Raman spectroscopy is employed to provide crucial structural insight, confirming that this mutant, with its disordered proton shuttle, fails to generate essential hydroxylase pathway intermediates, accounting for the loss in hydroxylase efficiency. Significantly, a corresponding spectroscopic study with the susceptible lyase substrate, 17-OH PREG, not only reveals an initially trapped peroxo-iron intermediate experiencing an H-bond interaction of the 17-OH group with the proximal oxygen of the Fe-Op -Ot fragment, facilitating peroxo- attack on the C20 carbon, but also unequivocally shows the presence of the subsequent hemiketal intermediate of the lyase reaction.

Effects of a High-Protein Diet on Cardiometabolic Health, Vascular Function, and Endocannabinoids-A PREVIEW Study.

An unfavorable lipid profile and being overweight are known mediators in the development of cardiovascular disease (CVD) risk. The effect of diet, particularly high in protein, remains under discussion. Therefore, this study examines the effects of a high-protein (HP) diet on cardiometabolic health and vascular function (i.e., endothelial function, arterial stiffness, and retinal microvascular structure), and the possible association with plasma endocannabinoids and endocannabinoid-related compounds in overweight participants. Thirty-eight participants (64.5 ± 5.9 (mean ± SD) years; body mass index (BMI) 28.9 ± 4.0 kg/m2) were measured for 48 h in a respiration chamber after body-weight maintenance for approximately 34 months following weight reduction. Diets with either a HP (n = 20) or moderate protein (MP; n = 18) content (25%/45%/30% vs. 15%/55%/30% protein/carbohydrate/fat) were provided in energy balance. Validated markers for cardiometabolic health (i.e., office blood pressure (BP) and serum lipoprotein concentrations) and vascular function (i.e., brachial artery flow-mediated vasodilation, pulse wave analysis and velocity, and retinal microvascular calibers) were measured before and after those 48 h. Additionally, 24 h ambulatory BP, plasma anandamide (AEA), 2-arachidonoylglycerol (2-AG), oleoylethanolamide (OEA), palmitoylethanolamide (PEA), and pregnenolone (PREG) were analyzed throughout the day. Office and ambulatory BP, serum lipoprotein concentrations, and vascular function markers were not different between the groups. Only heart rate (HR) was higher in the HP group. HR was positively associated with OEA, while OEA and PEA were also positively associated with total cholesterol (TC) and low-density lipoprotein (LDL) cholesterol concentrations. Vascular function markers were not associated with endocannabinoids (or endocannabinoid-related substances). In conclusion, the HP diet did not affect cardiometabolic health and vascular function in overweight participants after completing a weight-loss intervention. Furthermore, our data indicate a possible association between OEA and PEA with TC and LDL cholesterol.

Role of Endocannabinoids in Energy-Balance Regulation in Participants in the Postobese State-a PREVIEW Study.

ContextEndocannabinoids are suggested to play a role in energy balance regulation.ObjectiveWe aimed to investigate associations of endocannabinoid concentrations during the day with energy balance and adiposity and interactions with 2 diets differing in protein content in participants in the postobese phase with prediabetes.Design and ParticipantsParticipants (n = 38) were individually fed in energy balance with a medium protein (MP: 15:55:30% of energy from protein:carbohydrate:fat) or high-protein diet (HP: 25:45:30% energy from P:C:F) for 48 hours in a respiration chamber.Main Outcome MeasuresAssociations between energy balance, energy expenditure, respiratory quotient, and endocannabinoid concentrations during the day were assessed.ResultsPlasma-concentrations of anandamide (AEA), oleoylethanolamide (OEA), palmitoyethanolamide (PEA), and pregnenolone (PREG) significantly decreased during the day. This decrease was inversely related to body mass index (AEA) or body fat (%) (PEA; OEA). The lowest RQ value, before lunch, was inversely associated with concentrations of AEA and PEA before lunch. Area under the curve (AUC) of concentrations of AEA, 2-AG, PEA, and OEA were positively related to body fat% (P < .05).The HP and MP groups showed no differences in concentrations of AEA, OEA, PEA, and PREG, but the AUC of 2-arachidonoylglycerol (2-AG) was significantly higher in the HP vs the MP group.ConclusionsIn energy balance, only the endocannabinoid 2-AG changed in relation to protein level of the diet, whereas the endocannabinoid AEA and endocannabinoid-related compounds OEA and PEA reflected the gradual energy intake matching energy expenditure during the day.

Serum Neurosteroid Levels Are Associated With Cortical Thickness in Individuals Diagnosed With Posttraumatic Stress Disorder and History of Mild Traumatic Brain Injury.

Posttraumatic stress disorder (PTSD) co-occurring with mild traumatic brain injury (mTBI) is common in veterans. Worse clinical outcome in those with PTSD has been associated with decreased serum neurosteroid levels. Furthermore, decreased cortical thickness has been associated with both PTSD and mTBI. However, it is not known whether decreased neurosteroids are associated with decreased cortical thickness in PTSD co-occurring with mTBI. This study included 141 individuals divided into the following groups: (a) mTBI group (n = 32 [10 female, 22 male] veterans with a history of mTBI); (b) PTSD + mTBI group (n = 41 [6 female, 35 male] veterans with current PTSD with a history of mTBI); and (c) control group (n = 68 [35 female, 33 male] control participants), which were acquired through the Injury and Traumatic Stress (INTRuST) Clinical Consortium. Subjects underwent clinical assessment, magnetic resonance imaging at 3 T, and serum neurosteroid quantifications of allopregnanolone (ALLO) and pregnenolone (PREGN). Group differences in cortical thickness and associations between serum neurosteroid levels and cortical thickness were investigated. Cortical thickness was decreased in the PTSD + mTBI group compared with the other groups. In the PTSD + mTBI group, decreased cortical thickness was also associated with lower serum ALLO (right superior frontal cortex) and lower serum PREGN (left middle temporal and right orbitofrontal cortex). Cortical thickness in the middle temporal and orbitofrontal cortex was associated with PTSD symptom severity. There were no significant associations between neurosteroids and cortical thickness in the mTBI or control groups. Decreased cortical thickness in individuals with PTSD + mTBI is associated with decreased serum neurosteroid levels and greater PTSD symptom severity. Causality is unclear. However, future studies might investigate whether treatment with neurosteroids could counteract stress-induced neural atrophy in PTSD + mTBI by potentially preserving cortical thickness.