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The Journal of Biological Chemistry Aug 2023Neurosteroids, which are steroids synthesized by the nervous system, can exert neuromodulatory and neuroprotective effects via genomic and nongenomic pathways. The...
Neurosteroids, which are steroids synthesized by the nervous system, can exert neuromodulatory and neuroprotective effects via genomic and nongenomic pathways. The neurosteroid and major steroid precursor pregnenolone has therapeutical potential in various diseases, such as psychiatric and pain disorders, and may play important roles in myelination, neuroinflammation, neurotransmission, and neuroplasticity. Although pregnenolone is synthesized by CYP11A1 in peripheral steroidogenic organs, our recent study showed that pregnenolone must be synthesized by another mitochondrial cytochrome P450 (CYP450) enzyme other than CYP11A1 in human glial cells. Therefore, we sought to identify the CYP450 responsible for pregnenolone production in the human brain. Upon screening for CYP450s expressed in the human brain that have mitochondrial localization, we identified three enzyme candidates: CYP27A1, CYP1A1, and CYP1B1. We found that inhibition of CYP27A1 through inhibitors and siRNA knockdown did not negatively affect pregnenolone synthesis in human glial cells. Meanwhile, treatment of human glial cells with CYP1A1/CYP1B1 inhibitors significantly reduced pregnenolone production in the presence of 22(R)-hydroxycholesterol. We performed siRNA knockdown of CYP1A1 or CYP1B1 in human glial cells and found that only CYP1B1 knockdown significantly decreased pregnenolone production. Furthermore, overexpression of mitochondria-targeted CYP1B1 significantly increased pregnenolone production under basal conditions and in the presence of hydroxycholesterols and low-density lipoprotein. Inhibition of CYP1A1 and/or CYP1B1 via inhibitors or siRNA knockdown did not significantly reduce pregnenolone synthesis in human adrenal cortical cells, implying that CYP1B1 is not a major pregnenolone-producing enzyme in the periphery. These data suggest that mitochondrial CYP1B1 is involved in pregnenolone synthesis in human glial cells.
Topics: Humans; Brain; Cholesterol Side-Chain Cleavage Enzyme; Cytochrome P-450 CYP1A1; Cytochrome P-450 CYP1B1; Hydroxycholesterols; Mitochondria; Neuroglia; Pregnenolone; RNA, Small Interfering; Steroids
PubMed: 37442234
DOI: 10.1016/j.jbc.2023.105035 -
Molecules (Basel, Switzerland) Sep 2013Pregnenolone sulfate is a steroid metabolite with a plethora of actions and functions. As a neurosteroid, pregnenolone sulfate modulates a variety of ion channels,... (Review)
Review
Pregnenolone sulfate is a steroid metabolite with a plethora of actions and functions. As a neurosteroid, pregnenolone sulfate modulates a variety of ion channels, transporters, and enzymes. Interestingly, as a sulfated steroid, pregnenolone sulfate is not the final- or waste-product of pregnenolone being sulfated via a phase II metabolism reaction and renally excreted, as one would presume from the pharmacology textbook knowledge. Pregnenolone sulfate is also the source and thereby the starting point for subsequent steroid synthesis pathways. Most recently, pregnenolone sulfate has been functionally "upgraded" from modulator of ion channels to an activating ion channel ligand. This review will focus on molecular aspects of the neurosteroid, pregnenolone sulfate, its metabolism, concentrations in serum and tissues and last not least will summarize the functional data.
Topics: Animals; Humans; Ligands; Pregnenolone; Receptors, GABA; Receptors, N-Methyl-D-Aspartate; Signal Transduction; Transient Receptor Potential Channels
PubMed: 24084011
DOI: 10.3390/molecules181012012 -
Journal of Neuroinflammation Dec 2023Depression is two-to-three times more frequent among women. The hypothalamus, a sexually dimorphic area, has been implicated in the pathophysiology of depression....
BACKGROUND
Depression is two-to-three times more frequent among women. The hypothalamus, a sexually dimorphic area, has been implicated in the pathophysiology of depression. Neuroinflammation-induced hypothalamic dysfunction underlies behaviors associated with depression. The lipopolysaccharide (LPS)-induced mouse model of depression has been well-validated in numerous laboratories, including our own, and is widely used to investigate the relationship between neuroinflammation and depression. However, the sex-specific differences in metabolic alterations underlying depression-associated hypothalamic neuroinflammation remain unknown.
METHODS
Here, we employed the LPS-induced mouse model of depression to investigate hypothalamic metabolic changes in both male and female mice using a metabolomics approach. Through bioinformatics analysis, we confirmed the molecular pathways and biological processes associated with the identified metabolites. Furthermore, we employed quantitative real-time PCR, enzyme-linked immunosorbent assay, western blotting, and pharmacological interventions to further elucidate the underlying mechanisms.
RESULTS
A total of 124 and 61 differential metabolites (DMs) were detected in male and female mice with depressive-like behavior, respectively, compared to their respective sex-matched control groups. Moreover, a comparison between female and male model mice identified 37 DMs. We capitalized on biochemical clustering and functional enrichment analyses to define the major metabolic changes in these DMs. More than 55% of the DMs clustered into lipids and lipid-like molecules, and an imbalance in lipids metabolism was presented in the hypothalamus. Furthermore, steroidogenic pathway was confirmed as a potential sex-specific pathway in the hypothalamus of female mice with depression. Pregnenolone, an upstream component of the steroid hormone biosynthesis pathway, was downregulated in female mice with depressive-like phenotypes but not in males and had considerable relevance to depressive-like behaviors in females. Moreover, exogenous pregnenolone infusion reversed depressive-like behaviors in female mice with depression. The 5α-reductase type I (SRD5A1), a steroidogenic hub enzyme involved in pregnenolone metabolism, was increased in the hypothalamus of female mice with depression. Its inhibition increased hypothalamic pregnenolone levels and ameliorated depressive-like behaviors in female mice with depression.
CONCLUSIONS
Our study findings demonstrate a marked sexual dimorphism at the metabolic level in depression, particularly in hypothalamic steroidogenic metabolism, identifying a potential sex-specific pathway in female mice with depressive-like behaviors.
Topics: Humans; Mice; Male; Female; Animals; Depression; Neuroinflammatory Diseases; Lipopolysaccharides; Hypothalamus; Inflammation; Pregnenolone
PubMed: 38062440
DOI: 10.1186/s12974-023-02976-7 -
Journal of Alzheimer's Disease : JAD 2019Translocator protein 18 kDa (TSPO) is located in the mitochondrial outer membrane and plays an important role in steroidogenesis and cell survival. In the central...
Translocator protein 18 kDa (TSPO) is located in the mitochondrial outer membrane and plays an important role in steroidogenesis and cell survival. In the central nervous system (CNS), its expression is upregulated in neuropathologies such as Alzheimer's disease (AD). Previously, we demonstrated that two new TSPO ligands based on an imidazoquinazolinone termed 2a and 2b, stimulated pregnenolone synthesis and ATP production in vitro. In the present study, we compared their effects to those of TSPO ligands described in the literature (XBD173, SSR-180,575, and Ro5-4864) by profiling the mitochondrial bioenergetic phenotype before and after treatment and investigating the protective effects of these ligands after oxidative injury in a cellular model of AD overexpressing amyloid-β (Aβ). Of note, ATP levels increased with rising pregnenolone levels suggesting that the energetic performance of mitochondria is linked to an increased production of this neurosteroid via TSPO modulation. Our results further demonstrate that the TSPO ligands 2a and 2b exerted neuroprotective effects by improving mitochondrial respiration, reducing reactive oxygen species and thereby decreasing oxidative stress-induced cell death as well as lowering Aβ levels. The compounds 2a and 2b show similar or even better functional effects than those obtained with the reference TSPO ligands XBD173 and SSR-180.575. These findings indicate that the new TSPO ligands modulate mitochondrial bioenergetic phenotype and protect against oxidative injury probably through the de novo synthesis of neurosteroids, suggesting that these compounds could be potential new therapeutic tools for the treatment of neurodegenerative disease.
Topics: Cell Death; Cell Line, Tumor; Energy Metabolism; HEK293 Cells; Humans; Ligands; Mitochondria; Oxidative Stress; Pregnenolone; Quinazolinones; Reactive Oxygen Species; Receptors, GABA
PubMed: 31256132
DOI: 10.3233/JAD-190127 -
Journal of Neuroendocrinology Feb 2023Steroids and endocannabinoids are part of two modulatory systems and some evidence has shown their interconnections in several functions. Homeostasis is a common... (Review)
Review
Steroids and endocannabinoids are part of two modulatory systems and some evidence has shown their interconnections in several functions. Homeostasis is a common steady-state described in the body, which is settled by regulatory systems to counterbalance deregulated or allostatic set points towards an equilibrium. This regulation is of primary significance in the central nervous system for maintaining neuronal plasticity and preventing brain-related disorders. In this context, the recent discovery of the shutdown of the endocannabinoid system (ECS) overload by the neurosteroid pregnenolone has highlighted new endogenous mechanisms of ECS regulation related to cannabis-induced intoxication. These mechanisms involve a regulatory loop mediated by overactivation of the central type-1 cannabinoid receptor (CB1R), which triggers the production of its own regulator, pregnenolone. Therefore, this highlights a new process of regulation of steroidogenesis in the brain. Pregnenolone, long considered an inactive precursor of neurosteroids, can then act as an endogenous negative allosteric modulator of CB1R. The present review aims to shed light on a new framework for the role of ECS in the addictive characteristics of cannabis with the novel endogenous mechanism of ECS involving the neurosteroid pregnenolone. In addition, this new endogenous regulatory loop could provide a relevant therapeutic model in the current context of increasing recreational and medical use of cannabis.
Topics: Endocannabinoids; Cannabis; Neurosteroids; Brain; Pregnenolone; Receptor, Cannabinoid, CB1
PubMed: 36043319
DOI: 10.1111/jne.13191 -
British Journal of Pharmacology Oct 2023GABA receptors are regulated by numerous classes of allosteric modulators. However, regulation of receptor macroscopic desensitisation remains largely unexplored and may...
BACKGROUND AND PURPOSE
GABA receptors are regulated by numerous classes of allosteric modulators. However, regulation of receptor macroscopic desensitisation remains largely unexplored and may offer new therapeutic opportunities. Here, we report the emerging potential for modulating desensitisation with analogues of the endogenous inhibitory neurosteroid, pregnenolone sulfate.
EXPERIMENTAL APPROACH
New pregnenolone sulfate analogues were synthesised incorporating various heterocyclic substitutions located at the C-21 position on ring D. The pharmacological profiles of these compounds were assessed using electrophysiology and recombinant GABA receptors together with mutagenesis, molecular dynamics simulations, structural modelling and kinetic simulations.
KEY RESULTS
All seven analogues retained a negative allosteric modulatory capability whilst exhibiting diverse potencies. Interestingly, we observed differential effects on GABA current decay by compounds incorporating either a six- (compound 5) or five-membered heterocyclic ring (compound 6) on C-21, which was independent of their potencies as inhibitors. We propose that differences in molecular charges, and the targeted binding of analogues to specific states of the GABA receptor, are the most likely cause of the distinctive functional profiles.
CONCLUSIONS AND IMPLICATIONS
Our findings reveal that heterocyclic addition to inhibitory neurosteroids not only affected their potency and macroscopic efficacy but also affected innate receptor mechanisms that underlie desensitisation. Acute modulation of macroscopic desensitisation will determine the degree and duration of GABA inhibition, which are vital for the integration of neural circuit activity. Discovery of this form of modulation could present an opportunity for next-generation GABA receptor drug design and development.
Topics: Receptors, GABA-A; Pregnenolone; gamma-Aminobutyric Acid
PubMed: 37194503
DOI: 10.1111/bph.16143 -
Neuropharmacology Jul 2018γ-aminobutyric acid type A receptors (GABARs) are important components of the central nervous system and they are functionally tasked with controlling neuronal...
γ-aminobutyric acid type A receptors (GABARs) are important components of the central nervous system and they are functionally tasked with controlling neuronal excitability. These receptors are subject to post-translational modification and also to modulation by endogenous regulators, such as the neurosteroids. These modulators can either potentiate or inhibit GABAR function. Whilst the former class of neurosteroids are considered to bind to and act from the transmembrane domain of the receptor, the domains that are important for the inhibitory neurosteroids remain less clear. In this study, we systematically compare a panel of recombinant synaptic-type and extrasynaptic-type GABARs expressed in heterologous cell systems for their sensitivity to inhibition by the classic inhibitory neurosteroid, pregnenolone sulphate. Generally, peak GABA current responses were inhibited less compared to steady-state currents, implicating the desensitised state in inhibition. Moreover, pregnenolone sulphate inhibition increased with GABA concentration, but showed minimal voltage dependence. There was no strong dependence of inhibition on receptor subunit composition, the exception being the ρ1 receptor, which is markedly less sensitive. By using competition experiments with pregnenolone sulphate and the GABA channel blocker picrotoxinin, discrete binding sites are proposed. Furthermore, by assessing inhibition using site-directed mutagenesis and receptor chimeras comprising α, β or γ subunits with ρ1 subunits, the receptor transmembrane domains are strongly implicated in mediating inhibition and most likely the binding location for pregnenolone sulphate in GABARs. This article is part of the "Special Issue Dedicated to Norman G. Bowery".
Topics: Animals; Binding Sites; Cell Line; Humans; Membrane Potentials; Mice; Neurotransmitter Agents; Pentobarbital; Picrotoxin; Pregnenolone; Protein Domains; Receptors, GABA-A; Recombinant Proteins
PubMed: 29447845
DOI: 10.1016/j.neuropharm.2018.02.008 -
Pharmacology & Therapeutics Oct 2007Neurosteroids are a relatively new class of neuroactive compounds brought to prominence in the past 2 decades. Despite knowing of their presence in the nervous system of... (Review)
Review
Neurosteroids are a relatively new class of neuroactive compounds brought to prominence in the past 2 decades. Despite knowing of their presence in the nervous system of various species for over 20 years and knowing of their functions as GABA(A) and N-methyl-d-aspartate (NMDA) ligands, new and unexpected functions of these compounds are continuously being identified. Absence or reduced concentrations of neurosteroids during development and in adults may be associated with neurodevelopmental, psychiatric, or behavioral disorders. Treatment with physiologic or pharmacologic concentrations of these compounds may also promote neurogenesis, neuronal survival, myelination, increased memory, and reduced neurotoxicity. This review highlights what is currently known about the neurodevelopmental functions and mechanisms of action of 4 distinct neurosteroids: pregnenolone, progesterone, allopregnanolone, and dehydroepiandrosterone (DHEA).
Topics: Animals; Central Nervous System; Dehydroepiandrosterone; Humans; Pregnanolone; Pregnenolone; Progesterone; Steroids; Synaptic Transmission
PubMed: 17651807
DOI: 10.1016/j.pharmthera.2007.04.011 -
Environment International Jul 2022Hormones play critical roles in facilitating pregnancy progression and the onset of parturition. Several classes of environmental contaminants, including fine...
Hormones play critical roles in facilitating pregnancy progression and the onset of parturition. Several classes of environmental contaminants, including fine particulate matter (PM) and ambient temperature, have been shown to alter hormone biosynthesis or activity. However, epidemiologic research has not considered PM in relation to a broader range of steroid hormones, particularly in pregnant women. Using metabolomics data collected within 20-40 weeks of gestation in an ethnically diverse pregnancy cohort study, we identified 42 steroid hormones that we grouped into five classes (pregnenolone, androgens, estrogens, progestin, and corticosteroids) based on their biosynthesis type. We found that exposure to PM during the pre-conception and early prenatal periods was associated with higher maternal androgen concentrations in late pregnancy. We also detected a positive association between early pregnancy PM exposure and maternal pregnenolone levels and a marginal positive association between early pregnancy PM exposure and progestin levels. When considering each hormone metabolite individually, we found positive associations between early pregnancy PM exposure and five steroids, two of which survived multiple comparison testing: 11beta-hydroxyandrosterone glucuronide (a pregnenolone steroid) and adrosteroneglucuronide (a progestin steroid). None of the steroid classes were statistically significant associated with ambient temperature. In sex-stratified analyses, we did not detect any sex differences in our associations. This is the first study showing that exposure to fine particulate matter during the pre-conception and early prenatal periods can lead to altered steroid adaptation during the state of pregnancy, which has been shown to have potential consequences on maternal and child health.
Topics: Air Pollutants; Air Pollution; Child; Cohort Studies; Female; Humans; Male; Maternal Exposure; Particulate Matter; Pregnancy; Pregnenolone; Progestins; Steroids; Temperature
PubMed: 35700570
DOI: 10.1016/j.envint.2022.107320 -
British Journal of Anaesthesia Mar 1997We have studied the interaction of pregnenolone sulphate and pregnenolone with 5 beta-pregnanolone- and hexobarbitone-induced anaesthesia in male rats using an EEG...
We have studied the interaction of pregnenolone sulphate and pregnenolone with 5 beta-pregnanolone- and hexobarbitone-induced anaesthesia in male rats using an EEG threshold method. Burst suppression of the EEG of 1 s or more ("silent second" (SS)), was used as a criterion of deep anaesthesia. The effects of the steroid solvents albumin and beta-cyclodextrin were assessed by dose-response curves. Despite a significant increase in hexobarbitone threshold dose in relation to increased doses of albumin, there was no correlation between albumin dose and hexobarbitone concentrations in serum, fat and brain tissues. There was no significant difference in threshold concentrations of hexobarbitone between controls given albumin and those pretreated with pregnenolone. In subsequent experiments, 20% beta-cyclodextrin was used as steroid solvent and its volume was maintained at less than 3.0 ml kg-1 during pretreatment. Neither pregnenolone sulphate nor pregnenolone significantly altered the potency of 5 beta-pregnanolone for induction of anaesthesia. Furthermore, there was no interaction of pregnenolone sulphate and pregnenolone on induction of anaesthesia when hexobarbitone was used for anaesthesia.
Topics: Albumins; Anesthetics, Intravenous; Animals; Dose-Response Relationship, Drug; Drug Interactions; Electroencephalography; Hexobarbital; Male; Pregnanolone; Pregnenolone; Rats; Rats, Sprague-Dawley
PubMed: 9135318
DOI: 10.1093/bja/78.3.328