SciCombinator

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Concept: Pregnenolone

219

The calcium channel of sperm (CatSper) is essential for sperm hyperactivated motility and fertility. The steroid hormone progesterone activates CatSper of human sperm via binding to the serine hydrolase ABHD2. However, steroid specificity of ABHD2 has not been evaluated. Here, we explored whether steroid hormones to which human spermatozoa are exposed in the male and female genital tract influence CatSper activation via modulation of ABHD2. The results show that testosterone, estrogen, and hydrocortisone did not alter basal CatSper currents, whereas the neurosteroid pregnenolone sulfate exerted similar effects as progesterone, likely binding to the same site. However, physiological concentrations of testosterone and hydrocortisone inhibited CatSper activation by progesterone. Additionally, testosterone antagonized the effect of pregnenolone sulfate. We have also explored whether steroid-like molecules, such as the plant triterpenoids pristimerin and lupeol, affect sperm fertility. Interestingly, both compounds competed with progesterone and pregnenolone sulfate and significantly reduced CatSper activation by either steroid. Furthermore, pristimerin and lupeol considerably diminished hyperactivation of capacitated spermatozoa. These results indicate that (i) pregnenolone sulfate together with progesterone are the main steroids that activate CatSper and (ii) pristimerin and lupeol can act as contraceptive compounds by averting sperm hyperactivation, thus preventing fertilization.

Concepts: Cholesterol, Sperm, Estrogen, Testosterone, Spermatozoon, Progesterone, Steroid, Pregnenolone

18

NMDA receptors (NMDARs) mediate fast excitatory synaptic transmission and play a critical role in synaptic plasticity associated with learning and memory. NMDAR hypoactivity has been implicated in the pathophysiology of schizophrenia, and clinical studies reveal reduced negative symptoms of schizophrenia with a dose of pregnenolone that elevates serum levels of the neuroactive steroid pregnenolone sulfate (PregS). This report describes a novel process of delayed onset potentiation whereby PregS approximately doubles the cell’s response to NMDA via a mechanism that is pharmacologically and kinetically distinct from rapid positive allosteric modulation by PregS. The number of functional cell surface NMDARs in cortical neurons increases 60 -100% within 10 min of exposure to PregS as shown by surface biotinylation and affinity purification. Delayed onset potentiation is reversible and selective for expressed receptors containing the NR2A or NR2B, but not NR2C or NR2D, subunits. Moreover, substitution of NR2B J-K helices and M4 domain with the corresponding region of NR2D ablates rapid allosteric potentiation of the NMDA response by PregS but not delayed onset potentiation. This demonstrates that the initial phase of rapid positive allosteric modulation is not a first step in NMDAR upregulation. Delayed onset potentiation by PregS occurs via a non- canonical, pertussis toxin sensitive G-protein coupled and Ca(2+) dependent mechanism that is independent of NMDAR ion channel activation. Further investigation into the sequelae for PregS stimulated trafficking of NMDARs to the neuronal cell surface may uncover a new target for the pharmacological treatment of disorders in which NMDAR hypofunction has been implicated.

Concepts: Signal transduction, Action potential, Synaptic plasticity, Long-term depression, NMDA receptor, Membrane potential, Long-term potentiation, Pregnenolone

12

Local production of neurosteroids such as progesterone and allopregnanolone confers neuroprotection in central nervous system (CNS) inflammatory diseases. The mitochondrial translocator protein (TSPO) performs a rate-limiting step in the conversion of cholesterol to pregnenolone and its steroid derivatives. Previous studies have shown that TSPO is upregulated in microglia and astroglia during neural inflammation, and radiolabelled TSPO ligands such as PK11195 have been used to image and localize injury in the CNS. Recent studies have shown that modulating TSPO activity with pharmacological ligands such as etifoxine can initiate the production of neurosteroids locally in the injured CNS. In this study, we examined the effects of etifoxine, a clinically available anxiolytic drug, in the development and progression of mouse experimental autoimmune encephalomyelitis (EAE), an experimental model for multiple sclerosis (MS). Our results showed that etifoxine attenuated EAE severity when administered before the development of clinical signs and also improved symptomatic recovery when administered at the peak of the disease. In both cases, recovery was correlated with diminished inflammatory pathology in the lumbar spinal cord. Modulation of TSPO activity by etifoxine led to less peripheral immune cell infiltration of the spinal cord, and increased oligodendroglial regeneration after inflammatory demyelination in EAE. Our results suggest that a TSPO ligand, e.g. etifoxine, could be a potential new therapeutic option for MS with benefits that could be comparable to the administration of systemic steroids but potentially avoiding the detrimental side effects of long-term direct use of steroids.

Concepts: Immune system, Central nervous system, Nervous system, Neuron, Multiple sclerosis, Progesterone, Steroid, Pregnenolone

9

3α-5α-Tetrahydroprogesterone, a progesterone metabolite also known as allopregnanolone, and 5α-androstane-3α,17β-diol, a testosterone metabolite also known as 3α-androstanediol, are neuroactive steroids and positive GABAA receptor allosteric modulators. Both anorexia nervosa (AN) and obesity are complicated by affective co-morbidities and hypothalamic-pituitary-gonadal dysregulation. However, it is not known whether neuroactive steroid levels are abnormal at the extremes of the weight spectrum. We hypothesized that serum allopregnanolone and 3α-androstanediol levels would be decreased in AN compared to healthy controls (HC) and negatively associated with affective symptoms throughout the weight spectrum, independent of body mass index (BMI). Thirty-six women were 1 : 1 age-matched across three groups: AN, HC, and overweight/obese (OW/OB). AN were amenorrheic; HC and OW/OB were studied in the follicular phase. Fasting serum neuroactive steroids were measured by gas chromatography/mass spectrometry. Mean Hamilton depression and anxiety scores were highest in AN (p<0.0001). Mean serum allopregnanolone was lower in AN and OW/OB than HC (AN 95.3±56.4 vs OW/OB 73.8±31.3 vs HC 199.5±167.8 pg/ml, p=0.01), despite comparable mean serum progesterone. Allopregnanolone, but not progesterone, was negatively associated with depression and anxiety symptom severity, independent of BMI. Serum 3α-androstanediol levels did not differ among groups and were not associated with depression or anxiety scores, despite a significant negative association between free testosterone levels and both anxiety and depression severity. In conclusion, women at both extremes of the weight spectrum have low mean serum allopregnanolone, which is associated with increased depression and anxiety severity, independent of BMI. Neuroactive steroids such as allopregnanolone may be potential therapeutic targets for depression and anxiety in traditionally treatment-resistant groups including AN.Neuropsychopharmacology accepted article preview online, 01 November 2017. doi:10.1038/npp.2017.269.

Concepts: Cholesterol, Estrogen, Body mass index, Testosterone, Progesterone, Steroid, Pregnenolone, Neuroactive steroid

1

Neurosteroids are both endogenous and exogenous steroids that rapidly alter neuronal excitability through interactions with ligand-gated ion channels and other cell surface receptors. They are originated from cholesterol and have important implications for schizophrenia (SZ) pathophysiology and treatment strategies. Specifically, pregnenolone (PREG), progesterone (PROG) and allopregnanolone (ALLO) exhibit similar psychotropic properties. Using enzyme immunoassay, we compared the neurosteroids in PREG downstream pathways in plasma between healthy controls (HC, n = 43) and first-episode antipsychotic-naïve patients with SZ (FEAN-SZ, n = 53) before antipsychotic drug (APD) treatment. Comparisons were also made particularly along PREG-PROG-ALLO pathway in the same FEAN-SZ patients across multiple time points following initiation of treatment for 12 months (m). Firstly, at baseline, levels of PREG were significantly higher and those of ALLO were lower in FEAN-SZ than in HC, whereas PROG, cortisol, dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) were not different. Consequently, the molar ratios of ALLO/PREG and ALLO/PROG in FEAN-SZ were significantly reduced. Secondly, in response to APD at 1 month, ALLO levels in FEAN-SZ were markedly elevated, whereas PREG and PROG levels decreased. Thirdly, among FEAN-SZ, lower levels of PROG (reflecting higher conversion to ALLO) at baseline may predict better therapeutic outcome after 1 month of APD treatment. These findings point to the perturbations of the PREG-PROG-ALLO pathway early in psychosis, and further study of this pathway may inform alternative and innovative therapeutic targets for SZ.

Concepts: Receptor, Dehydroepiandrosterone, Progesterone, Steroid, Antipsychotic, Schizophrenia, Ligand-gated ion channel, Pregnenolone

1

Many dysfunctional and chronic pain conditions overlap. This review describes the different modes of chronic deregulation of the adaptive response to stress which may be a common factor for these conditions. Several types of dysfunction can be identified within the hypothalamo-pituitary-adrenal axis: basal hypercortisolism, hyper-reactivity, basal hypocortisolism and hypo-reactivity. Neuroactive steroid synthesis is another component of the adaptive response to stress. Dehydroepiandrosterone (DHEA) and its sulfated form DHEA-S, and progesterone and its derivatives are synthetized in cutaneous, nervous, and adipose cells. They are neuroactive factors that act locally. They may have a role in the localization of the symptoms and their levels can vary both in the central nervous system and in the periphery. Persistent changes in neuroactive steroid levels or precursors can induce localized neurodegeneration. The autonomic nervous system is another component of the stress response. Its dysfunction in chronic stress responses can be expressed by decreased basal parasympathethic activity, increased basal sympathetic activity or sympathetic hyporeactivity to a stressful stimulus. The immune and genetic systems also participate. The helper-T cells Th1 secrete pro-inflammatory cytokines such as IL-1-β, IL-2, IL-6, IL-8, IL-12, IFN-γ, and TNF-α, whereas Th2 secrete anti-inflammatory cytokines: IL-4, IL-10, IGF-10, IL-13. Chronic deregulation of the Th1/Th2 balance can occur in favor of anti- or pro-inflammatory direction, locally or systemically. Individual vulnerability to stress can be due to environmental factors but can also be genetically influenced. Genetic polymorphisms and epigenetics are the main keys to understanding the influence of genetics on the response of individuals to constraints.

Concepts: Central nervous system, Nervous system, Genetics, Gene expression, Brain, Autonomic nervous system, Sympathetic nervous system, Pregnenolone

1

Neurosteroid dehydropiandrosterone (DHEA) and its sulphate (DHEAS) are reported to have modulatory effects on neuronal excitabillity and synaptic plasticity. DHEA and DHEAS are synthesized in central and peripheral nervous system from cholesterol or steroidal precursors imported from peripheral sources. There is accumulating evidence that alterations in DHEA(S) levels may be involved in the pathophysiology of schizophrenia. The possible effects of DHEA(S) as augmentation therapy in schizophrenia, related to psychological and somatic aspects of this disease, are discussed.

Concepts: Central nervous system, Nervous system, Neuron, Brain, Neuroscience, Dehydroepiandrosterone, Dopamine, Pregnenolone

1

A 57-year-old woman presented with hirsutism, hair loss on the scalp, and deepening of her voice. Previous testing had revealed elevated total and free testosterone levels and a normal dehydroepiandrosterone sulfate level. A diagnostic procedure was performed.

Concepts: Estrogen, Testosterone, Androgen, Androstenedione, Pregnenolone, Zona reticularis

1

Recently, LC-MS/MS was stated to be the method of choice to measure sex steroids. Because information on the mutual agreement of LC-MS/MS methods is scarce, we compared 7 published LC-MS/MS methods for the simultaneous measurement of testosterone, androstenedione, and dehydroepiandrosterone (DHEA).

Concepts: Estrogen, Testosterone, Androgen, Dehydroepiandrosterone, Androstenedione, Androgens, Sex steroid, Pregnenolone

1

Observations performed in a subset of patients treated for male pattern hair loss seem to indicate that persistent sexual side effects as well as anxious/depressive symptomatology were reported even after discontinuation of finasteride treatment. Due to the capability of finasteride to block the metabolism of progesterone (PROG) and/or testosterone (T) we have evaluated, by liquid chromatography-tandem mass spectrometry, the levels of several neuroactive steroids in paired plasma and cerebrospinal fluid (CSF) samples obtained from post-finasteride patients and in healthy controls. At the examination, post-finasteride patients referred muscular stiffness, cramps, tremors and chronic fatigue in the absence of clinical evidence of any muscular disorder or strength reduction. Severity of the anxious/depressive symptoms were quite variable in their frequency, overall all the subjects had a fairly complex and constant neuropsychiatric pattern. Assessment of neuroactive steroid levels in CSF show a decrease of PROG and its metabolites, dihydroprogesterone (DHP) and tetrahydroprogesterone (THP), associated to an increase of its precursor pregnenolone (PREG). Altered levels were also observed for T and its metabolites. Thus, a significant decrease of dihydrotestosterone (DHT) associated to an increase of T as well as of 3α-diol was detected. Changes in neuroactive steroid levels also occurred in plasma. An increase of PREG, T, 3α-diol, 3β-diol and 17β-estradiol was associated to decreased levels of DHP and THP. The present observations show that altered levels of neuroactive steroids, associated to depression symptoms, are present in androgenic alopecia patients even after discontinuation of the finasteride treatment.

Concepts: Metabolism, Estrogen, Testosterone, Progesterone, Steroid, Pregnenolone, Androgenic alopecia, Neuroactive steroid