-
The Journal of Cell Biology Apr 1993The rat central nervous system (CNS) has previously been shown to synthesize pregnenolone (PREG) and convert it to progesterone (PROG) and 7 alpha-hydroxy-PREG (7...
The rat central nervous system (CNS) has previously been shown to synthesize pregnenolone (PREG) and convert it to progesterone (PROG) and 7 alpha-hydroxy-PREG (7 alpha-OH PREG). Astrocytes, which participate to the regulation of the CNS function, might be involved in the metabolism of neurosteroids. Purified type 1 astrocytes were obtained from fetal rat forebrain with the use of selective culture conditions and were identified by immunostaining with specific antibodies (GFAP+, A2B5-). They were plated at low, intermediate, or high densities (2.5-5 x 10(5), 1-2 x 10(6), or 4-8 x 10(6) cells/dish, respectively) and maintained for 21 d. They were then incubated with 14C-PREG and 14C-DHEA for 24 h and the steroids extracted from cells and media were analyzed. Most radioactive derivatives were released into incubation media. Two metabolic pathways were mainly observed. PREG and DHEA were oxidized to PROG and androstenedione (ADIONE), respectively, [3 beta-hydroxysteroid-dehydrogenase, delta 5-->4 3-ketosteroid-isomerase (3 beta-HSD) activity], and converted to 7 alpha-OH PREG and 7 alpha-OH DHEA, respectively (7 alpha-hydroxylase activity). After low density plating, the formation of PROG and ADIONE was approximately 10% of incubated radioactivity, tenfold larger than that of 7 alpha-hydroxylated metabolites. In contrast, after high density plating, low levels of PROG and ADIONE were formed, whereas the conversion to either 7 alpha-OH PREG or 7 alpha-OH DHEA was > or = 50%. The results expressed per cell indicated that the 3 beta-HSD activity was almost completely inhibited at high cell density, in contrast to the 7 alpha-hydroxylation which was maintained or increased. The pattern of steroid metabolism was related to cell density at the time of measurement and not to an early commitment of cells: when primary cultures were plated at high density (8 x 10(6) cells/dish), then subcultured after several dilutions (3-, 9-, or 27-fold), the 3 beta-HSD activity was recovered only at low density. Furthermore, when 5 x 10(5) cells were centrifuged and the resulting clusters were plated, 3 beta-HSD activity was decreased, whereas steroid 7 alpha-hydroxylation was enhanced. This implies that cell density per se, but neither cell number nor a diffusible factor(s) is involved in the regulation of steroid metabolism. We conclude that astrocytes in culture metabolize PREG and DHEA, and that the metabolic conversions and, therefore, the related enzymatic activities depend on cell-to-cell contacts.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Animals; Astrocytes; Carbon Monoxide; Cell Count; Cells, Cultured; Dehydroepiandrosterone; Female; Hydroxylation; Immunoenzyme Techniques; Kinetics; Oxidation-Reduction; Pregnancy; Pregnenolone; Rats; Rats, Sprague-Dawley
PubMed: 8458866
DOI: 10.1083/jcb.121.1.135 -
Frontiers in Endocrinology 2021Cytochrome P450s (CYPs) are an essential family of enzymes in the human body. They play a crucial role in metabolism, especially in human steroid biosynthesis. Reactions...
Cytochrome P450s (CYPs) are an essential family of enzymes in the human body. They play a crucial role in metabolism, especially in human steroid biosynthesis. Reactions catalyzed by these enzymes are highly stereo- and regio-specific. Lack or severe malfunctions of CYPs can cause severe diseases and even shorten life. Hence, investigations on metabolic reactions and structural requirements of substrates are crucial to gain further knowledge on the relevance of different enzymes in the human body functions and the origin of diseases. One key enzyme in the biosynthesis of gluco- and mineralocorticoids is CYP21A2, also known as steroid 21-hydroxylase. To investigate the steric and regional requirements of substrates for this enzyme, we performed whole-cell biotransformation assays using a strain of fission yeast recombinantly expressing CYP21A2. The progestogens progesterone, pregnenolone, and their 17α-hydroxy-derivatives were used as substrates. After incubation, samples were analyzed using gas chromatography coupled to mass spectrometry. For progesterone and 17α-hydroxyprogesterone, their corresponding 21-hydroxylated metabolites 11-deoxycorticosterone and 11-deoxycortisol were detected, while after incubation of pregnenolone and 17α-hydroxypregnenolone, no hydroxylated product was observed. Findings were confirmed with authentic reference material. Molecular docking experiments agree with these results and suggest that interaction between the 3-oxo group and arginine-234 of the enzyme is a strict requirement. The presented results demonstrate once more that the presence of an oxo-group in position 3 of the steroid is indispensable, while a 3-hydroxy group prevents hydroxylation in position C-21 by CYP21A2. This knowledge may be transferred to other CYP21A2 substrates and hence help to gain essential insights into steroid metabolism.
Topics: 17-alpha-Hydroxypregnenolone; Adrenal Cortex Hormones; Catalytic Domain; Cytochrome P-450 Enzyme System; Gas Chromatography-Mass Spectrometry; Humans; Hydroxylation; Models, Molecular; Molecular Docking Simulation; Pregnenolone; Progesterone; Schizosaccharomyces; Steroid 17-alpha-Hydroxylase; Steroid 21-Hydroxylase; Steroids; Substrate Specificity
PubMed: 34149610
DOI: 10.3389/fendo.2021.633785 -
Scientific Reports Mar 2024Pregnenolone sulfate is a steroid metabolite of the steroidogenesis precursor, pregnenolone, with similar functional properties, including immunosuppression. We recently...
Pregnenolone sulfate is a steroid metabolite of the steroidogenesis precursor, pregnenolone, with similar functional properties, including immunosuppression. We recently reported an elevation in serum levels of pregnenolone sulfate in children with malaria, contributing to an immunosuppressed state. Yet, the molecular mechanisms in which this steroid exerts its immunoregulatory functions are lacking. In this study, we examined the effects of pregnenolone sulfate on T cell viability, proliferation and transcriptome. We observed a pregnenolone sulfate dose-dependent induction of T cell death and reduction in proliferation. RNA sequencing analysis of pregnenolone sulfate-treated T cells for 2 and 24 h revealed the downregulation of pro-inflammatory genes and the upregulation of the steroid nuclear receptor superfamily, NR4A, as early-response genes. We also report a strong activation of the integrated stress response mediated by the upregulation of EIF2AK3. These results contribute to the knowledge on transcriptional regulation driving the immunoregulatory effects of pregnenolone sulfate on T cells.
Topics: Child; Humans; Pregnenolone; Up-Regulation; Steroids; T-Lymphocytes
PubMed: 38514798
DOI: 10.1038/s41598-024-57327-0 -
Cells Oct 2020Neurosteroids are steroids synthetized in the nervous system, with the first step of steroidogenesis taking place within mitochondria with the synthesis of pregnenolone....
Neurosteroids are steroids synthetized in the nervous system, with the first step of steroidogenesis taking place within mitochondria with the synthesis of pregnenolone. They exert important brain-specific functions by playing a role in neurotransmission, learning and memory processes, and neuroprotection. Here, we show for the first time that mitochondrial neurosteroidogenesis follows a circadian rhythm and correlates with the rhythmic changes in mitochondrial morphology. We used synchronized human A172 glioma cells, which are steroidogenic cells with a functional core molecular clock, to show that pregnenolone levels and translocator protein (TSPO) are controlled by the clock, probably via circadian regulation of mitochondrial fusion/fission. Key findings were recapitulated in mouse brains. We also showed that genetic or pharmacological abrogation of fusion/fission activity, as well as disturbing the core molecular clock, abolished circadian rhythms of pregnenolone and TSPO. Our findings provide new insights into the crosstalk between mitochondrial function (here, neurosteroidogenesis) and circadian cycles.
Topics: Animals; Biological Clocks; Cell Line, Tumor; Circadian Rhythm; Humans; Mice; Mitochondria; Mitochondrial Dynamics; Models, Biological; Pregnenolone; Receptors, GABA
PubMed: 33086741
DOI: 10.3390/cells9102323 -
Cell Reports Mar 2024Osteoclasts play a central role in cancer-cell-induced osteolysis, but the molecular mechanisms of osteoclast activation during bone metastasis formation are...
Osteoclasts play a central role in cancer-cell-induced osteolysis, but the molecular mechanisms of osteoclast activation during bone metastasis formation are incompletely understood. By performing RNA sequencing on a mouse breast carcinoma cell line with higher bone-metastatic potential, here we identify the enzyme CYP11A1 strongly upregulated in osteotropic tumor cells. Genetic deletion of Cyp11a1 in tumor cells leads to a decreased number of bone metastases but does not alter primary tumor growth and lung metastasis formation in mice. The product of CYP11A1 activity, pregnenolone, increases the number and function of mouse and human osteoclasts in vitro but does not alter osteoclast-specific gene expression. Instead, tumor-derived pregnenolone strongly enhances the fusion of pre-osteoclasts via prolyl 4-hydroxylase subunit beta (P4HB), identified as a potential interaction partner of pregnenolone. Taken together, our results demonstrate that Cyp11a1-expressing tumor cells produce pregnenolone, which is capable of promoting bone metastasis formation and osteoclast development via P4HB.
Topics: Humans; Female; Osteogenesis; Cholesterol Side-Chain Cleavage Enzyme; Cell Line, Tumor; Bone Neoplasms; Osteoclasts; Pregnenolone; Breast Neoplasms; Cell Differentiation
PubMed: 38489269
DOI: 10.1016/j.celrep.2024.113936 -
The Journal of Biological Chemistry Jul 2022Neurosteroids, modulators of neuronal and glial cell functions, are synthesized in the nervous system from cholesterol. In peripheral steroidogenic tissues, cholesterol...
Neurosteroids, modulators of neuronal and glial cell functions, are synthesized in the nervous system from cholesterol. In peripheral steroidogenic tissues, cholesterol is converted to the major steroid precursor pregnenolone by the CYP11A1 enzyme. Although pregnenolone is one of the most abundant neurosteroids in the brain, expression of CYP11A1 is difficult to detect. We found that human glial cells produced pregnenolone, detectable by mass spectrometry and ELISA, despite the absence of observable immunoreactive CYP11A1 protein. Unlike testicular and adrenal cortical cells, pregnenolone production in glial cells was not inhibited by CYP11A1 inhibitors DL-aminoglutethimide and ketoconazole. Furthermore, addition of hydroxycholesterols increased pregnenolone synthesis, suggesting desmolase activity that was not blocked by DL-aminoglutethimide or ketoconazole. We explored three different possibilities for an alternative pathway for glial cell pregnenolone synthesis: (1) regulation by reactive oxygen species, (2) metabolism via a different CYP11A1 isoform, and (3) metabolism via another CYP450 enzyme. First, we found oxidants and antioxidants had no significant effects on pregnenolone synthesis, suggesting it is not regulated by reactive oxygen species. Second, overexpression of CYP11A1 isoform b did not alter synthesis, indicating use of another CYP11A1 isoform is unlikely. Finally, we show nitric oxide and iron chelators deferoxamine and deferiprone significantly inhibited pregnenolone production, indicating involvement of another CYP450 enzyme. Ultimately, knockdown of endoplasmic reticulum cofactor NADPH-cytochrome P450 reductase had no effect, while knockdown of mitochondrial CYP450 cofactor ferredoxin reductase inhibited pregnenolone production. These data suggest that pregnenolone is synthesized by a mitochondrial cytochrome P450 enzyme other than CYP11A1 in human glial cells.
Topics: Aminoglutethimide; Cholesterol; Cholesterol Side-Chain Cleavage Enzyme; Humans; Ketoconazole; Neuroglia; Neurosteroids; Pregnenolone; Reactive Oxygen Species
PubMed: 35688208
DOI: 10.1016/j.jbc.2022.102110 -
International Journal of Molecular... Dec 2022CDKL5 deficiency disorder (CDD) is an X-linked neurodevelopmental disorder characterised by early-onset drug-resistant epilepsy and impaired cognitive and motor skills....
CDKL5 deficiency disorder (CDD) is an X-linked neurodevelopmental disorder characterised by early-onset drug-resistant epilepsy and impaired cognitive and motor skills. CDD is caused by mutations in cyclin-dependent kinase-like 5 (CDKL5), which plays a well-known role in regulating excitatory neurotransmission, while its effect on neuronal inhibition has been poorly investigated. We explored the potential role of CDKL5 in the inhibitory compartment in -KO male mice and primary hippocampal neurons and found that CDKL5 interacts with gephyrin and collybistin, two crucial organisers of the inhibitory postsynaptic sites. Through molecular and electrophysiological approaches, we demonstrated that CDKL5 loss causes a reduced number of gephyrin puncta and surface exposed γ subunit-containing GABA receptors, impacting the frequency of miniature inhibitory postsynaptic currents, which we ascribe to a postsynaptic function of CDKL5. In line with previous data showing that CDKL5 loss impacts microtubule (MT) dynamics, we showed that treatment with pregnenolone-methyl-ether (PME), which promotes MT dynamics, rescues the above defects. The impact of CDKL5 deficiency on inhibitory neurotransmission might explain the presence of drug-resistant epilepsy and cognitive defects in CDD patients. Moreover, our results may pave the way for drug-based therapies that could bypass the need for CDKL5 and provide effective therapeutic strategies for CDD patients.
Topics: Male; Mice; Animals; Neurosteroids; Pregnenolone; Spasms, Infantile; Ethers; Mice, Knockout; Protein Serine-Threonine Kinases
PubMed: 36613509
DOI: 10.3390/ijms24010068 -
Cell Reports May 2014Recent papers from Mahata et al. and Bereshchenko et al. reveal how steroids steer immune responses by tipping T helper (Th) subset balances and activities. Pregnenolone...
Recent papers from Mahata et al. and Bereshchenko et al. reveal how steroids steer immune responses by tipping T helper (Th) subset balances and activities. Pregnenolone produced by Th2 cells mediates immunosuppressive responses, and glucocorticoids stimulate regulatory T cell development via the induction of GILZ expression.
Topics: Animals; Glucocorticoids; Humans; Pregnenolone; RNA; T-Lymphocytes, Regulatory; Th1 Cells; Th2 Cells; Transcription Factors; Transforming Growth Factor beta
PubMed: 24856295
DOI: 10.1016/j.celrep.2014.04.041 -
Journal of Lipid Research Dec 2009Pregnenolone (PREG) and dehydroepiandrosterone (DHEA), and their respective sulfated forms PREGS and DHEAS, were among the first steroids to be identified in rodent...
Pregnenolone (PREG) and dehydroepiandrosterone (DHEA), and their respective sulfated forms PREGS and DHEAS, were among the first steroids to be identified in rodent brain. However, unreliable steroid isolation and solvolysis procedures resulted in errors, particularly in the case of brain steroid sulfates analyzed by radioimmunology or GC-MS of liberated free steroids. By using a solid-phase extraction recycling/elution procedure, allowing the strict separation of sulfated, free, and fatty acid esters of PREG and DHEA, PREGS and DHEAS, unlike free PREG, were not detected in rat and mouse brain and plasma. Conversely, considerable amounts of PREG and DHEA were released from unknown precursor(s) present in the lipoidal fraction, distinct from fatty acid ester conjugates. Chromatographic and mass spectrometric studies of the nature of the precursor(s) showed that autoxidation of brain cholesterol (CHOL) was responsible for the release of PREG and DHEA from the lipoidal fraction. When inappropriate protocols were used, CHOL was also the precursor of PREG and DHEA obtained from the fraction assumed to contain sulfated steroids. In contrast, free PREG was definitely confirmed as an endogenous steroid in rat brain. Our study shows that an early removal of CHOL from brain extracts coupled to well-validated extraction and fractionation procedures are prerequisites for reliable measurements of free and conjugated PREG and DHEA by GC-MS or other indirect methods.
Topics: Animals; Brain; Brain Chemistry; Cholesterol; Dehydroepiandrosterone; Male; Mice; Oxidation-Reduction; Pregnenolone; Rats; Rats, Sprague-Dawley
PubMed: 19506304
DOI: 10.1194/jlr.M900162-JLR200 -
Pharmacological Reports : PR 2006Neurosteroids are a group of steroid hormones synthesized by the brain in the presence of steroidogenic enzymes. Specific neurosteroids modulate function of several... (Review)
Review
Neurosteroids are a group of steroid hormones synthesized by the brain in the presence of steroidogenic enzymes. Specific neurosteroids modulate function of several receptors, and also regulate growth of neurons, myelinization and synaptogenesis in the central nervous system. Some neurosteroids have been shown to display neuroprotective properties, which may have important implications for their potential use in the treatment of various neuropathologies such as: age-dependent dementia, stroke, epilepsy, spinal cord injury, Alzheimer's disease (AD), Parkinson's disease (PD) and Niemann-Pick type C disease (NP-C). This paper focuses on neuroprotection afforded by neurosteroids.
Topics: Alzheimer Disease; Animals; Dehydroepiandrosterone Sulfate; GABA Modulators; Humans; Neuroprotective Agents; Niemann-Pick Disease, Type C; Parkinson Disease; Pregnenolone; Progesterone; Steroids
PubMed: 16845207
DOI: No ID Found