Structures of human steroidogenic cytochrome P450 17A1 with substrates

Optical annealing of peroxo-ferric intermediates in CYP17A1 and product formation

Human cytochrome P450 CYP17A1 catalyzes the hydroxylation of pregnenolone and progesterone at the C17 position, with subsequent C17-C20 bond scission, to form dehydroepiandrosterone and androstenedione respectively. The first hydroxylation reaction is faster in H2O than in D2O, while the second carbon‑carbon bond scission event demonstrates an inverse solvent isotope effect, which is more pronounced for 17-hydroxy pregnenolone. In order to better understand the cause of this difference, we compared the optical absorption spectra of oxygenated CYP17A1 with the four substrates (pregnenolone, progesterone, 17-hydroxy pregnenolone and 17-hydroxy progesterone) in both H2O and D2O. We also studied the temperature-dependent decay of the peroxo-ferric and hydroperoxo-ferric intermediates generated by cryoradiolysis of the corresponding oxygenated heme proteins at 77 K. For both pregnenolone and 17-hydroxypregnenolone, annealing of the peroxo-intermediates was observed at lower temperatures in H2O than in D2O. In contrast, no solvent isotope effect was detected when progesterone or 17-hydroxyprogesterone were used as substrates. These differences are attributed to their different positioning in the P450 active site with respect to the heme bound peroxo (Fe-OO-) moiety, which is in agreement with earlier structural and spectroscopic investigations. Analysis of the samples run in both H2O and in D2O, where 17-hydroxyprogesterone is the substrate, demonstrated significant (∼25%) yield of androstenedione product relative to the oxygenated starting material.

Explore the mechanism of Astragalus membranaceus and Poria cocos drug pair in improving immunity based on network pharmacology

The aim of this study was to investigate the key targets and molecular mechanisms of the drug pair Astragalus membranaceus and Poria cocos (HFDP) in the treatment of immunity. We utilized network pharmacology, molecular docking, and immune infiltration techniques in conjunction with data from the GEO database. Previous clinical studies have shown that HFDP has a positive impact on immune function. We first identified the active ingredients and targets of HFDP from the Traditional Chinese Medicine Systems Pharmacology database and the Swiss Target Prediction database, respectively. Next, we retrieved the differentially expressed genes (DEGs) related to immunity from the GEO databases. The intersection targets of the drugs and diseases were then analyzed using the STRING database for protein-protein interaction (PPI) network analysis, and the core targets were determined through topological analysis. Finally, the intersection genes were further analyzed using the DAVID database for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses. Subsequently, by analyzing the expression and prognostic survival of 12 core targets, 5 core target genes were identified, and molecular docking between the hub genes and immunity was performed. Finally, we used the CIBERSORT algorithm to analyze the immune infiltration of immunity genes In this study, 34 effective ingredients of HFDP, 530 target genes, and 568 differential genes were identified. GO and KEGG analysis showed that the intersection genes of HFDP targets and immunity-related genes were mainly related to complement and coagulation cascades, cytokine receptors, and retinol metabolism pathways. The molecular docking results showed that the 5 core genes had obvious affinity for the active ingredients of HFDP, which could be used as potential targets to improve the immunity of HFDP. Our findings suggest that HFDP is characterized by "multiple components, multiple targets, and multiple pathways" in regulating immunity. It may play an essential role in regulating immunity by regulating the expression and polymorphism of the central target genes ESR1, JUN, CYP3A4, CYP2C9, and SERPINE1.

In silico and in vitro assessment of drugs potentially causing adverse effects by inhibiting CYP17A1

Cytochrome P450 enzymes (CYPs) play a crucial role in the metabolism and synthesis of various compound classes. While drug-metabolizing CYP enzymes are frequently investigated as anti-targets, the inhibition of CYP enzymes involved in adrenal steroidogenesis is not well studied. The steroidogenic enzyme CYP17A1 is a dual-function enzyme catalyzing hydroxylase and lyase reactions relevant for the biosynthesis of adrenal glucocorticoids and androgens. Inhibition of CYP17A1-hydroxylase leads to pseudohyperaldosteronism with subsequent excessive mineralocorticoid receptor activation, hypertension and hypokalemia. In contrast, specific inhibition of the lyase function might be beneficial for the treatment of prostate cancer by decreasing adrenal androgen levels. This study combined in silico and in vitro methods to identify drugs inhibiting CYP17A1. The most potent CYP17A1 inhibitors identified are serdemetan, mocetinostat, nolatrexed, liarozole, and talarozole. While some of these drugs are currently under investigation for the treatment of various cancers, their potential for the treatment of prostate cancer is yet to be explored. The DrugBank database was screened for CYP17A1 inhibitors, to increase the awareness for the risk of drug-induced pseudohyperaldosteronism and to highlight drugs so far unknown for their potential to cause side effects resulting from CYP17A1 inhibition.

Characterization of the Cytochrome P450 CYP716C52 in Celastrol Biosynthesis and Its Applications in Engineered Saccharomyces cerevisiae

Celastrol is a bioactive pentacyclic triterpenoid with promising therapeutic effects that is mainly distributed in Celastraceae plants. Although some enzymes involved in the celastrol biosynthesis pathway have been reported, many biosynthetic steps remain unknown. Herein, transcriptomics and metabolic profiles of multiple species in Celastraceae were integrated to screen for cytochrome P450s (CYPs) that are closely related to celastrol biosynthesis. The CYP716 enzyme, TwCYP716C52, was found to be able to oxidize the C-2 position of polpunonic acid, a precursor of celastrol, to form the wilforic acid C. RNAi-mediated repression of TwCYP716C52 in Tripterygium wilfordii suspension cells further confirmed its involvement in celastrol biosynthesis. The C-2 catalytic mechanisms of TwCYP716C52 were further explored by using molecular docking and site-directed mutagenesis experiments. Moreover, a modular optimization strategy was used to construct an engineered yeast to produce wilforic acid C at a titer of 5.8 mg·L-1. This study elucidates the celastrol biosynthetic pathway and provides important functional genes and sufficient precursors for further enzyme discovery.

Effect of Essential Oil Components on the Activity of Steroidogenic Cytochrome P450

Endocrine-disrupting chemicals (EDCs) may impact the development of prostate cancer (PCa) by altering the steroid metabolism. Although their exact mechanism of action in controlling tumor growth is not known, EDCs may inhibit steroidogenic enzymes such as CYP17A1 or CYP19A1 which are involved in the production of androgens or estrogens. High levels of circulating androgens are linked to PCa in men and Polycystic Ovary Syndrome (PCOS) in women. Essential oils or their metabolites, like lavender oil and tea tree oil, have been reported to act as potential EDCs and contribute towards sex steroid imbalance in cases of prepubertal gynecomastia in boys and premature thelarche in girls due to the exposure to lavender-based fragrances. We screened a range of EO components to determine their effects on CYP17A1 and CYP19A1. Computational docking was performed to predict the binding of essential oils with CYP17A1 and CYP19A1. Functional assays were performed using the radiolabeled substrates or Liquid Chromatography-High-Resolution Mass Spectrometry and cell viability assays were carried out in LNCaP cells. Many of the tested compounds bind close to the active site of CYP17A1, and (+)-Cedrol had the best binding with CYP17A1 and CYP19A1. Eucalyptol, Dihydro-β-Ionone, and (-)-α-pinene showed 20% to 40% inhibition of dehydroepiandrosterone production; and some compounds also effected CYP19A1. Extensive use of these essential oils in various beauty and hygiene products is common, but only limited knowledge about their potential detrimental side effects exists. Our results suggest that prolonged exposure to some of these essential oils may result in steroid imbalances. On the other hand, due to their effect on lowering androgen output and ability to bind at the active site of steroidogenic cytochrome P450s, these compounds may provide design ideas for novel compounds against hyperandrogenic disorders such as PCa and PCOS.

Computational investigation of four isoquinoline alkaloids against polycystic ovarian syndrome

Hyperandrogenism, insulin resistance, and estrogen dominance are the prime defining traits of women with polycystic ovarian syndrome which disrupts hormonal, adrenal, or ovarian functions resulting in impaired folliculogenesis and excess androgen production. The purpose of this study is to identify an appropriate bioactive antagonistic ligand from isoquinoline alkaloids [palmatine (PAL), jatrorrhizine (JAT), magnoflorine (MAG) and berberine (BBR)] from stems of Tinospora cordifolia. Phytocomponents inhibit/prevent androgenic, estrogenic, and steroidogenic receptors, insulin binding, and resultant hyperandrogenism. Intending to develop new inhibitors for human androgen receptor (1E3G), insulin receptor (3EKK), estrogen receptor beta (1U3S), and human steroidogenic cytochromeP450 17A1 (6WR0), here we report the docking studies by employing a flexible ligand docking approach using AutodockVina 4.2.6. ADMET screened swissADME and toxicological predictions to identify novel and potent inhibitors against PCOS. Binding affinity was obtained using Schrodinger. Two ligands, mainly BER (-8.23) and PAL (-6.71) showed the best docking score against androgen receptors. A molecular docking study reveals that compounds BBR and PAL were found to be tight binder at the active site of IE3G. Molecular dynamics results suggest that BBR and PAL showed good binding stability of active site residues. The present study corroborates the molecular dynamics of the compound BBR and PAL, potent Inhibitors of IE3G, having therapeutic potential for PCOS. We project that this study's findings will be helpful in drug development efforts targeting PCOS. Hence isoquinoline alkaloids (BER& PAL) have potential roles against androgen receptors, and in specific PCOS, scientific evaluation has been put forth based on virtual screening.Communicated by Ramaswamy H. Sarma.

Abiraterone Acetate Complexes with Biometals: Synthesis, Characterization in Solid and Solution, and the Nature of Chemical Bonding

Abiraterone acetate (AbirAc) is the most used steroidal therapeutic agent for treatment of prostate cancer. The mainly hydrophobic molecular surface of AbirAc results in its poor solubility and plays an important role for retention of abiraterone in the cavity of the receptor formed by peptide chains and heme fragments. In order to evaluate the hydrolytic stability of AbirAc, to modify its solubility by formation of new solid forms and to model bonding of this medication with the heme, a series of d-metal complexes with AbirAc was obtained. AbirAc remains stable in water, acetonitrile, tetrahydrofuran, and ethanol, and readily interacts with dications as a terminal ligand to create discrete complexes, including [FePC(AbirAc)2] and [ZnTPP(AbirAc)] (H2PC = phthalocyanine and H2TPP = 5,10,15,20-tetraphenylporphyrine) models for ligand-receptor bonding. In reactions with silver(I) nitrate, AbirAc acts as a bridge ligand. Energies of chemical bonding between AbirAc and these cations vary from 97 to 235 kJ mol-1 and exceed those between metal atoms and water molecules. This can be indicative of the ability of abiraterone to replace solvent molecules in the coordination sphere of biometals in living cells, although the model [ZnTPP] complex remains stable in CDCl3, CD2Cl2, and 1,1,2,2-tetrachloroethane-d2 solvents and decomposes in polar dimethylsulfoxide-d6 and methanol-d4 solvents, as follows from the 1H DOSY spectra. Dynamics of its behavior in 1,1,2,2-tetrachloroethane-d2 were studied by ROESY and NMR spectra.

Transcriptional changes in multiple endocrine organs from lethal cases of COVID-19

Altered circulating hormone and metabolite levels have been reported during and post-COVID-19. Yet, studies of gene expression at the tissue level capable of identifying the causes of endocrine dysfunctions are lacking. Transcript levels of endocrine-specific genes were analyzed in five endocrine organs of lethal COVID-19 cases. Overall, 116 autoptic specimens from 77 individuals (50 COVID-19 cases and 27 uninfected controls) were included. Samples were tested for the SARS-CoV-2 genome. The adrenals, pancreas, ovary, thyroid, and white adipose tissue (WAT) were investigated. Transcript levels of 42 endocrine-specific and 3 interferon-stimulated genes (ISGs) were measured and compared between COVID-19 cases (virus-positive and virus-negative in each tissue) and uninfected controls. ISG transcript levels were enhanced in SARS-CoV-2-positive tissues. Endocrine-specific genes (e.g., HSD3B2, INS, IAPP, TSHR, FOXE1, LEP, and CRYGD) were deregulated in COVID-19 cases in an organ-specific manner. Transcription of organ-specific genes was suppressed in virus-positive specimens of the ovary, pancreas, and thyroid but enhanced in the adrenals. In WAT of COVID-19 cases, transcription of ISGs and leptin was enhanced independently of virus detection in tissue. Though vaccination and prior infection have a protective role against acute and long-term effects of COVID-19, clinicians must be aware that endocrine manifestations can derive from virus-induced and/or stress-induced transcriptional changes of individual endocrine genes. KEY MESSAGES: • SARS-CoV-2 can infect adipose tissue, adrenals, ovary, pancreas and thyroid. • Infection of endocrine organs induces interferon response. • Interferon response is observed in adipose tissue independently of virus presence. • Endocrine-specific genes are deregulated in an organ-specific manner in COVID-19. • Transcription of crucial genes such as INS, TSHR and LEP is altered in COVID-19.

Crosstalk between ferroptosis and steroid hormone signaling in gynecologic cancers

Ferroptosis is a novel types of regulated cell death and is widely studied in cancers and many other diseases in recent years. It is characterized by iron accumulation and intense lipid peroxidation that ultimately inducing oxidative damage. So far, signaling pathways related to ferroptosis are involved in all aspects of determining cell fate, including oxidative phosphorylation, metal-ion transport, energy metabolism and cholesterol synthesis progress, et al. Recently, accumulated studies have demonstrated that ferroptosis is associated with gynecological oncology related to steroid hormone signaling. This review trends to summarize the mechanisms and applications of ferroptosis in cancers related to estrogen and progesterone, which is expected to provide a theoretical basis for the prevention and treatment of gynecologic cancers.

Recombinant Technologies Facilitate Drug Metabolism, Pharmacokinetics, and General Biomedical Research

The development of safe and effective medications requires a profound understanding of their pharmacokinetic (PK) and pharmacodynamic properties. PK studies have been built through investigation of enzymes and transporters that drive drug absorption, distribution, metabolism, and excretion (ADME). Like many other disciplines, the study of ADME gene products and their functions has been revolutionized through the invention and widespread adoption of recombinant DNA technologies. Recombinant DNA technologies use expression vectors such as plasmids to achieve heterologous expression of a desired transgene in a specified host organism. This has enabled the purification of recombinant ADME gene products for functional and structural characterization, allowing investigators to elucidate their roles in drug metabolism and disposition. This strategy has also been used to offer recombinant or bioengineered RNA (BioRNA) agents to investigate the posttranscriptional regulation of ADME genes. Conventional research with small noncoding RNAs such as microRNAs (miRNAs) and small interfering RNAs has been dependent on synthetic RNA analogs that are known to carry a range of chemical modifications expected to improve stability and PK properties. Indeed, a novel transfer RNA fused pre-miRNA carrier-based bioengineering platform technology has been established to offer consistent and high-yield production of unparalleled BioRNA molecules from Escherichia coli fermentation. These BioRNAs are produced and processed inside living cells to better recapitulate the properties of natural RNAs, representing superior research tools to investigate regulatory mechanisms behind ADME. SIGNIFICANCE STATEMENT: This review article summarizes recombinant DNA technologies that have been an incredible boon in the study of drug metabolism and PK, providing investigators with powerful tools to express nearly any ADME gene products for functional and structural studies. It further overviews novel recombinant RNA technologies and discusses the utilities of bioengineered RNA agents for the investigation of ADME gene regulation and general biomedical research.

Non-steroidal CYP17A1 Inhibitors: Discovery and Assessment

CYP17A1 is an enzyme that plays a major role in steroidogenesis and is critically involved in the biosynthesis of steroid hormones. Therefore, it remains an attractive target in several serious hormone-dependent cancer diseases, such as prostate cancer and breast cancer. The medicinal chemistry community has been committed to the discovery and development of CYP17A1 inhibitors for many years, particularly for the treatment of castration-resistant prostate cancer. The current Perspective reflects upon the discovery and evaluation of non-steroidal CYP17A1 inhibitors from a medicinal chemistry angle. Emphasis is placed on the structural aspects of the target, key learnings from the presented chemotypes, and design guidelines for future inhibitors.

Steroid 17α-hydroxylase/17, 20-lyase (cytochrome P450 17A1)

Cytochrome P450 (P450) 17A1 plays a key role in steroidogenesis, in that this enzyme catalyzes the 17α-hydroxylation of both pregnenolone and progesterone, followed by a lyase reaction to cleave the C-20 land C-21 carbons from each steroid. The reactions are important in the production of both glucocorticoids and androgens. The enzyme is critical in humans but is also a drug target in treatment of prostate cancer. Detailed methods are described for the heterologous expression of human P450 17A1 in bacteria, purification of the recombinant enzyme, reconstitution of the enzyme system in the presence of cytochrome b5, and chromatographic procedures for sensitive analyses of reaction products. Historic assay approaches are reviewed. Some information is also provided about outstanding questions in the research field, including catalytic mechanisms and searches for selective inhibitors.

Pyridine-containing substrate analogs are restricted from accessing the human cytochrome P450 8B1 active site by tryptophan 281

The human oxysterol 12α-hydroxylase cytochrome P450 8B1 (CYP8B1) is a validated drug target for both type 2 diabetes and nonalcoholic fatty liver disease, but effective selective inhibitors are not yet available. Herein, steroidal substrate-mimicking compounds with a pyridine ring appended to the C12 site of metabolism were designed as inhibitors, synthesized, and evaluated in terms of their functional and structural interactions with CYP8B1. While the pyridine nitrogen was intended to coordinate the CYP8B1 active site heme iron, none of these compounds elicited shifts in the CYP8B1 Soret absorbance consistent with this type of interaction. However, when CYP8B1 was cocrystallized with the pyridine-containing compound with the 3-keto-Δ4 steroid backbone most similar to the endogenous substrate, it was apparent that this ligand was bound in a channel leading to the active site, instead of near the heme iron. Inspection of this structure suggested that tryptophan 281 directly above the heme might restrict active site binding of potential inhibitors with this design. This hypothesis was supported when a CYP8B1 W281F mutation did allow all three compounds to coordinate the heme iron as designed. These results indicated that the design of next-generation CYP8B1 inhibitors should be compatible with the low-ceiling tryptophan immediately above the heme iron.

Hydroxylation and lyase reactions of steroids catalyzed by mouse cytochrome P450 17A1 (Cyp17a1)

Cytochrome P450 17A1 (CYP17A1) catalyzes 17α-hydroxylation and 17,20-lyase reactions with steroid hormones. Mice contain an orthologous Cyp17a1 enzyme in the genome, and its amino acid sequence has high similarity with human CYP17A1. We purified recombinant mouse Cyp17a1 and characterized its oxidation reactions with progesterone and pregnenolone. The open reading frame of the mouse Cyp17a1 gene was inserted and successfully expressed in Escherichia coli and then purified using Ni²⁺-nitrilotriacetic acid (NTA) affinity column chromatography. Purified mouse Cyp17a1 displayed typical Type I binding titration spectral changes upon the addition of progesterone, 17α-OH progesterone, pregnenolone, and 17α-OH pregnenolone, with similar binding affinities to those of human CYP17A1. Catalytic activities for 17α-hydroxylation and 17,20-lyase reactions were studied using ultra-performance liquid chromatography (UPLC)-mass spectrometry analysis. Mouse Cyp17a1 showed cytochrome b₅ stimulation in catalysis. In comparison to human enzyme, much higher specificity constants (k_cat/K_m) were observed with mouse Cyp17a1. In the reactions of Δ4-steroids (progesterone and 17α-OH progesterone), the specificity constants were 2100 times higher than the human enzyme. The addition of cytochrome b₅ produced significant stimulation of 17,20-lyase activities of mouse Cyp17a1. Two Arg mutants of mouse Cyp17a1 (R347H and R358Q) displayed a larger decrease in 17,20-lyase reaction (from 17α-OH pregnenolone to dehydroepiandrosterone, DHEA) than 17α-hydroxylation, indicating that -as in human CYP17A1-these basic residues in mouse Cyp17a1 are important in interacting with the cytochrome b₅ protein in the lyase reactions.

Human cytochrome P450 17A1 structures with metabolites of prostate cancer drug abiraterone reveal substrate-binding plasticity and a second binding site

Abiraterone acetate is a first-line therapy for castration-resistant prostate cancer. This prodrug is deacetylated in vivo to abiraterone, which is a potent and specific inhibitor of cytochrome P450 17A1 (CYP17A1). CYP17A1 performs two sequential steps that are required for the biosynthesis of androgens that drive prostate cancer proliferation, analogous to estrogens in breast cancer. Abiraterone can be further metabolized in vivo on the steroid A ring to multiple metabolites that also inhibit CYP17A1. Despite its design as an active-site-directed substrate analog, abiraterone and its metabolites demonstrate mixed competitive/noncompetitive inhibition. To understand their binding, we solved the X-ray structures of CYP17A1 with three primary abiraterone metabolites. Despite different conformations of the steroid A ring and substituents, all three bound in the CYP17A1 active site with the steroid core packed against the I helix and the A ring C3 keto or hydroxyl oxygen forming a hydrogen bond with N202 similar to abiraterone itself. The structure of CYP17A1 with 3-keto, 5α-abiraterone was solved to 2.0 Å, the highest resolution to date for a CYP17A1 complex. This structure had additional electron density near the F/G loop, which is likely a second molecule of the inhibitor and which may explain the noncompetitive inhibition. Mutation of the adjacent Asn52 to Tyr positions its side chain in this space, maintains enzyme activity, and prevents binding of the peripheral ligand. Collectively, our findings provide further insight into abiraterone metabolite binding and CYP17A1 function.

Rational design of thermophilic CYP119 for progesterone hydroxylation by in silico mutagenesis and docking screening

Steroid-based chemicals can affect the metabolism, immune functions, and development of sexual characteristics. Because of these effects, steroid derivatives are widely used in the pharmaceutical industry. Progesterone is a steroid-based hormone that mainly controls the ovulation period of women but is also a precursor molecule for the synthesis of important hormones like testosterone and cortisone. Cytochrome P450 (CYP) enzymes are important for the production of hydroxyprogesterones in the industry since they can catalyze regio- and enantioselective hydroxylation reactions. Although human CYP enzymes can catalyze hydroxyprogesterone synthesis with high selectivity, these enzymes are membrane bound, which limits their application for industrial production. CYP119 is a soluble and thermophilic enzyme from the archaea Sulfolobus acidocaldarius. Even though the native substrate of the enzyme is not known, CYP119 can catalyze styrene epoxidation, lauric acid hydroxylation, and Amplex®Red peroxidation. In this work, an in silico mutagenesis approach was used to design CYP119 mutants with high progesterone affinity. Energy scores of progesterone docking simulations were used for the design and elimination of single, double, and triple mutants of CYP119. Among designed 674 mutants, five of them match the criteria for progesterone hydroxylation. The most common mutation of these five mutants, L69G mutant was analyzed using independent molecular dynamics (MD) simulations in comparison with the wild-type (WT) enzyme. L69G CYP119, was expressed and isolated from Escherichia coli; it showed 800-fold higher affinity for progesterone compared to WT CYP119. L69G CYP119 also catalyzed progesterone hydroxylation. The novel designed enzyme L69G CYP119 is a potential versatile biocatalyst for progesterone hydroxylation that is expected to be stable under industrial production conditions.

Four Decades of Cytochrome P450 2B Research: From Protein Adducts to Protein Structures and Beyond

This article features selected findings from the senior author and colleagues dating back to 1978 and covering approximately three-fourths of the 60 years since the discovery of cytochrome P450. Considering the vast number of P450 enzymes in this amazing superfamily and their importance for so many fields of science and medicine, including drug design and development, drug therapy, environmental health, and biotechnology, a comprehensive review of even a single topic is daunting. To make a meaningful contribution to the 50th anniversary of Drug Metabolism and Disposition, we trace the development of the research in a single P450 laboratory through the eyes of seven individuals with different backgrounds, perspectives, and subsequent career trajectories. All co-authors are united in their fascination for the structural basis of mammalian P450 substrate and inhibitor selectivity and using such information to improve drug design and therapy. An underlying theme is how technological advances enable scientific discoveries that were impossible and even inconceivable to prior generations. The work performed spans the continuum from: 1) purification of P450 enzymes from animal tissues to purification of expressed human P450 enzymes and their site-directed mutants from bacteria; 2) inhibition, metabolism, and spectral studies to isothermal titration calorimetry, deuterium exchange mass spectrometry, and NMR; 3) homology models based on bacterial P450 X-ray crystal structures to rabbit and human P450 structures in complex with a wide variety of ligands. Our hope is that humanizing the scientific endeavor will encourage new generations of scientists to make fundamental new discoveries in the P450 field. SIGNIFICANCE STATEMENT: The manuscript summarizes four decades of work from Dr. James Halpert's laboratory, whose investigations have shaped the cytochrome P450 field, and provides insightful perspectives of the co-authors. This work will also inspire future drug metabolism scientists to make critical new discoveries in the cytochrome P450 field.

The Role of Certain Polymorphic Variants in Genes, Previously Associated with Blood Pressure Values, with Reference to the Risk of Development of Coronary Artery Disease

The aim of the study was to analyze the effect of polymorphic variants previously associated with arterial hypertension (AH) in Genome Wide Association Studies (GWASs) in/next to genes and locuses CYP7A1 and PLEKHA7 on the development of coronary artery disease (CAD) in Bulgarian patients. A hundred and nine consecutive patients with angiographically documented CAD were studied. The genotyping was done with 7900 HT Fast Real-Time PCR (Applied Biosystems) with TaqMan® method. The control group consisted of 192 healthy population controls, selected from the bio- bank of the Molecular Medicine Center. SPSS and PLINK were used for the statistical analysis with level of significance < 0.05 and confidence interval 95%. The mean age of the studied patients was 63.71 ± 9.35 years; 35 (35%) females. Previous myocardial infarction (MI) had 38(38%); one-vessel – 39 (39%); two-vessel – 28 (28%); three-vessel disease – 34 (34%); 43 (43%) were with diabetes mellitus; 92 (92%) – with arterial hypertension (AH); 77 (77%) – with dyslipidemia; 42 (42%) were smokers; 25 (25%) were obese. We did not find any significant association between CAD and poly- morphism rs11191548 near CYP17A1 and only a tendency for genotype of rs381815 in PLEKHA7 (p = 0.06; OR 0.64; CI 0.40-1.02 for CAD) under dominant model. This is of practical importance both for studying the genetic aspects of CAD in the future and for enlargement of the current database.

Follicle isolation methods reveal plasticity of granulosa cell steroidogenic capacity during mouse in vitro follicle growth

Follicles are the functional unit of the ovary and several methods have been developed to grow follicles ex vivo, which recapitulate key events of oogenesis and folliculogenesis. Enzymatic digestion protocols are often used to increase the yield of follicles from the ovary. However, the impact of these protocols on the outermost theca and granulosa cells, and thereby follicle function, is not well defined. To investigate the impact of enzymatic digestion on follicle function, we collected preantral follicles from CD1 mice either by enzymatic digestion (Enzy-FL) or mechanical isolation (Mech-FL) and compared follicle growth, steroidogenesis and cell differentiation within an encapsulated in vitro follicle growth system which maintains the 3D architecture of the oocyte and its surrounding somatic cells. Follicles were encapsulated in 0.5% alginate and cultured for 8 days. Compared with Enzy-FL, Mech-FL grew more rapidly and produced significantly higher levels of androstenedione, estradiol and progesterone. The expression of theca-interstitial cell marker genes, Cyp17a1, which encodes 17-hydroxylase/17, 20-lyase and catalyzes the hydroxylation of pregnenolone and progesterone to 17-hydroxypregnenolone and 17-hydroxyprogesterone, and the conversion of these products into dehydroepiandrosterone and androstenedione, and Star, which encodes a transport protein essential for cholesterol entry into mitochondria, were also higher in Mech-FL than in Enzy-FL. Mech-FL maintained an intact theca-interstitial layer on the outer edge of the follicle that phenocopied in vivo patterns as confirmed by alkaline phosphatase staining, whereas theca-interstitial cells were absent from Enzy-FL from the onset of culture. Therefore, preservation of the theca cell layer at the onset of culture better supports follicle growth and function. Interestingly, granulosa cells in the outermost layers of Enzy-FL expressed CYP17A1 by Day 4 of culture while maintaining inhibin α-subunit expression and a cuboidal nucleus. Thus, in the absence of theca-interstitial cells, granulosa cells have the potential to differentiate into androgen-producing cells. This work may have implications for human follicle culture, where enzymatic isolation is required owing to the density of the ovarian cortex.

Arthrospira platensis nanoparticles defeat against diabetes-induced testicular injury in rat targeting, oxidative, apoptotic, and steroidogenesis pathways

Varieties of studies have been used to investigate the health benefits of Spirulina (Arthrospira platensis); however, more research is needed to examine if its nano form may be utilized to treat or prevent several chronic diseases. So, we designed this study to explore the effect and the cellular intracellular mechanisms by which Arthrospira platensis Nanoparticles (NSP) alleviates the testicular injury induced by diabetes in male Wistar rats. Eighty Wistar male rats (n = 80) were randomly allocated into eight groups. Group 1 is untreated rats (control), Group 2 including STZ-induced diabetic rats with 65 mg/kg body weight STZ (STZ-diabetic), Group 3-5: including diabetic rats treated with NSP1, NSP2, and NSP3 at 0.25, 0.5, and 1 mg/kg body weight, respectively, once daily orally by the aid of gastric gavage for 12 consecutive weeks and groups 6-8 include normal rats received NSP (0.25, 0.5, and 1 mg/kg body weight once daily orally. The identical volume of normal saline was injected into both control and diabetic rats. After 12 weeks of diabetes induction, the rats were killed. According to our findings, NSP administration to diabetic rats enhances the total body weight and the weight of testes and accessory glands; in addition, NSP significantly reduced nitric oxide and malondialdehyde in testicular tissue improved sperm parameters. Intriguingly, it raises testicular GSH and SOD activity by a significant amount (p < 0.05). As well, Oral administration of NSP to diabetic rats resulted in a decrease in the blood glucose levels, HA1C, induced in the diabetic group, which overcame the diabetic complications NSP caused down-regulation of apoptotic genes with upregulation of BCL-2 mRNA expression (p < 0.05) and prominent up-regulation of steroidogenesis genes expression level in testes in comparison to the diabetic rats which resulted in improving the decreased levels of testosterone hormone, FSH, and LH induced by diabetes. In the same way, our histopathological findings support our biochemical and molecular findings; in conclusion, NSP exerted a protective effect against reproductive dysfunction induced by diabetes not only through its high antioxidant and hypoglycemic action but also through its down-regulation of Apoptotic genes and up-regulation of steroidogenesis regulatory genes expression level in diabetic testes.

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.

Mulberrin inhibits Botrytis cinerea for strawberry storage by interfering with the bioactivity of 14α-demethylase (CYP51)

Currently, chemical agents hold great promise in preventing and combating Botrytis cinerea. However, the antifungal mechanism of some agents for B. cinerea remains rather vague, imposing restrictions on the research and development of novel antifungal inhibitors. In this work, we discovered that mulberrin (MBN), a natural compound from the root bark of Ramulus Mori, with an IC₅₀ of 1.38 μM together, demonstrated marked anti-14α-demethylase (CYP51) activity through high throughput virtual screening and in vitro bioactivity assay. The computational biology results demonstrated that MBN and its derivatives were bound to the catalytic activity region of CYP51, but only MBN could form a strong π-cation interaction with the Fe ion of heme in CYP51 via the 2-methylpent-2-ene moiety at atom C9. MBN had a stronger binding free energy than the other three compounds with CYP51, implying that the 2-methylpent-2-ene moiety at atom C9 is a critical pharmacophore for CYP51 inhibitors. Subsequently, through an antifungal test, MBN demonstrated excellent anti-B. cinerea activity by inhibiting CYP51 activity. The EC₅₀ values of MBN toward hyphal growth and spore germination in B. cinerea were 17.27 and 9.56 μg mL^-1, respectively. The bioactivity loss of CYP51 by direct interaction with MBN induced the increase of cell membrane permeability, membrane destruction, and cell death. Meanwhile, in the B. cinerea infection model, MBN significantly prolonged the preservation of strawberries by preventing B. cinerea from infecting strawberries and could be used as a potential natural preserving agent for storing fruits.

Oviducal gland transcriptomics of Octopus maya through physiological stages and the negative effects of temperature on fertilization

Background

Elevated temperatures reduce fertilization and egg-laying rates in the octopus species. However, the molecular mechanisms that control the onset of fertilization and egg-laying in the octopus' oviducal gland are still unclear; and the effect of temperature on the expression of key reproductive genes is unknown. This study aims to better understand the molecular bases of octopus fertilization and egg-laying, and how they are affected by elevated temperatures.

Method

RNA-seq of oviducal glands was performed for samples before, during, and after fertilization and their transcriptomic profiles were compared. Also, at the fertilization stage, the optimal and thermal-stress conditions were contrasted. Expression levels of key reproductive genes were validated via RT-qPCR.

Results

In mated females before egg-laying, genes required for the synthesis of spermine, spermidine, which may prevent premature fertilization, and the myomodulin neuropeptide were upregulated. Among the genes with higher expression at the fertilization stage, we found those encoding the receptors of serotonin, dopamine, and progesterone; genes involved in the assembly and motility of the sperm flagellum; genes that participate in the interaction between male and female gametes; and genes associated with the synthesis of eggshell mucoproteins. At temperatures above the optimal range for reproduction, mated females reduced the fertilization rate. This response coincided with the upregulation of myomodulin and APGW-amide neuropeptides. Also, genes associated with fertilization like LGALS3, VWC2, and Pcsk1 were downregulated at elevated temperatures. Similarly, in senescent females, genes involved in fertilization were downregulated but those involved in the metabolism of steroid hormones like SRD5A1 were highly expressed.

Full-Length Transcriptome Sequences Provide Insight Into Hermaphroditism of Freshwater Pearl Mussel Hyriopsis schlegelii

The freshwater mussel Hyriopsis schlegelii is a cultured bivalve in China, and the quality of the pearls produced is affected by the type of gonads. However, because of the lack of a published genome and the complexity of sex determination, research on sex reversal and development of this species is limited. In this study, Illumina RNA-seq and PacBio Isoform Sequencing (Iso-Seq) were combined to analyze the gonads of H. schlegelii. A total of 201,481 high-quality transcripts were generated. The study identified 7,922 differentially expressed genes in three comparison group (females versus males, hermaphrodites versus females, and hermaphrodites versus males). Twenty-four genes were identified as potential sex-related genes, including sox9 and wnt4 involved in sex determination, and vtg, cyp17a1 and 17β-hsd2 involved in gonadal development. We also speculated a possible pathways for the formation of hermaphroditism in H. schlegelii. The data provide a clear view of the transcriptome for H. schlegelii gonads and will be valuable in elucidating the mechanisms of gonad development.

Metabolomic and transcriptomic responses of mouse testis to the dextran sulfate sodium induced colitis

Inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis, are widespread in developed countries and gradually increasing in developing countries. Evidences showed that man with CD has a decrease of serum testosterone, but how IBD take effects on testicular testosterone synthesis is not well elucidated. To investigate the effects of IBD on testis, we analyzed testicular metabolome and transcriptome data of the dextran sulfate sodium (DSS) induced IBD mice. As a result, metabolomic data showed that DSS indeed induced androgen decrease in mouse testis. Correspondingly, androgen synthesis associated genes, especially Lhcgr, were down-regulated in DSS testis. From the metabolomic data, we found vitamin intake associated metabolites vitamin B2 and pyridoxamine were significantly decreased, whereas fatty acid metabolism associated molecules N-lauroylglycine and N-decanoylglycine were increased in DSS testis. In addition, we found 8-hydroxy-deoxyguanosine, a DNA oxidative damage marker, and 8-oxoguanine, a molecule responsible for DNA damage repair, were also changed in DSS testis. Simultaneously, our data also showed that DSS up-regulated the expression of meiosis initiation associated gene Stra8 and oxygen transport associated genes in testis. In summary, these results depicted the complex effects of colitis on testis. These metabolites and transcripts changed in DSS testis could be used as potential targets for IBD treatment or symptom relieve.

Hexaconazole exposure ravages biosynthesis pathway of steroid hormones: revealed by molecular dynamics and interaction

Widespread application of hexaconazole for agriculture purpose poses a threat to human health by disrupting normal endocrine homeostasis. To avoid adverse health effects on human, it is crucial to identify the effects of hexaconazole on key enzymes responsible for steroidal hormone synthesis. In view of this, present study was conducted to investigate the interaction mechanisms of hexaconazole with key enzymes in comparison with their food drug administration (FDA) approved inhibitor by molecular docking and molecular dynamics simulations. Results indicate that hexaconazole contacts with the active site of the key enzymes required for steroidal hormonal synthesis. Results pertaining to root-mean-square deviation, root-mean-square calculation, radius of gyration, hydrogen bonding and solvent accessible surface area exhibited that the interaction pattern and stability of interaction of hexaconazole was similar to enzyme specific inhibitor. In addition, ligand and enzyme complex interaction energy of hexaconazole was almost similar to key enzyme and FDA-approved enzyme specific inhibitor complex. This study offers a molecular level of understanding of hexaconazole with different enzymes required for steroidal hormonal synthesis. Findings of the study clearly suggest that hexaconazole has efficacy to stably interact with various enzyme required to progress the pathway of hormonal synthesis. If incessant exposure of hexaconazole occurs during agricultural work it may lead to ravage hormonal synthesis or potent endocrine disruption. The result of binding energy and complex interaction energy is depicted in the graphical abstract.

Synthesis and Structure–Activity Relationships of Novel Non-Steroidal CYP17A1 Inhibitors as Potential Prostate Cancer Agents

Twenty new compounds, targeting CYP17A1, were synthesized, based on our previous work on a benzimidazole scaffold, and their biological activity evaluated. Inhibition of CYP17A1 is an important modality in the treatment of prostate cancer, which remains the most abundant cancer type in men. The biological assessment included CYP17A1 hydroxylase and lyase inhibition, CYP3A4 and P450 oxidoreductase (POR) inhibition, as well as antiproliferative activity in PC3 prostate cancer cells. The most potent compounds were selected for further analyses including in silico modeling. This combined effort resulted in a compound (comp 2, IC₅₀ 1.2 µM, in CYP17A1) with a potency comparable to abiraterone and selectivity towards the other targets tested. In addition, the data provided an understanding of the structure–activity relationship of this novel non-steroidal compound class.

Diverse reactions catalyzed by cytochrome P450 and biosynthesis of steroid hormone

Steroid hormones modulate numerous physiological processes in various higher organisms. Research on the physiology, biosynthesis, and metabolic degradation of steroid hormones is crucial for developing drugs, agrochemicals, and anthelmintics. Most steroid hormone biosynthetic pathways, excluding those in insects, have been elucidated, and the roles of several cytochrome P450s (CYPs, P450s), heme (iron protoporphyrin IX)-containing monooxygenases, have been identified. Specifically, P450s of the animal steroid hormone biosynthetic pathways and their three dimensional structures and reaction mechanisms have been extensively studied; however, the mechanisms of several uncommon P450 reactions involved in animal steroid hormone biosynthesis and structures and reaction mechanisms of various P450s involved in plant and insect steroid hormone biosynthesis remain unclear. Recently, we determined the crystal structure of P450 responsible for the first and rate-determining step in brassinosteroids biosynthesis and clarified the regio- and stereo-selectivity in the hydroxylation reaction mechanism. In this review, we have outlined the general catalytic cycle, reaction mechanism, and structure of P450s. Additionally, we have described the recent advances in research on the reaction mechanisms of steroid hormone biosynthesis-related P450s, some of which catalyze unusual P450 reactions including C–C bond cleavage reactions by utilizing either a heme–peroxo anion species or compound I as an active oxidizing species. This review article is an extended version of the Japanese article, Structure and mechanism of cytochrome P450s involved in steroid hormone biosynthesis, published in SEIBUTSU BUTSURI Vol. 61, p. 189–191 (2021).

Inhibition of Cytochrome P450 Enzymes by Drugs-Molecular Basis and Practical Applications

Drug-drug interactions are a major cause of hospitalization and deaths related to drug use. A large fraction of these is due to inhibition of enzymes involved in drug metabolism and transport, particularly cytochrome P450 (P450) enzymes. Understanding basic mechanisms of enzyme inhibition is important, particularly in terms of reversibility and the use of the appropriate parameters. In addition to drug-drug interactions, issues have involved interactions of drugs with foods and natural products related to P450 enzymes. Predicting drug-drug interactions is a major effort in drug development in the pharmaceutical industry and regulatory agencies. With appropriate in vitro experiments, it is possible to stratify clinical drug-drug interaction studies. A better understanding of drug interactions and training of physicians and pharmacists has developed. Finally, some P450s have been the targets of drugs in some cancers and other disease states.

Single-cell transcriptome analysis identifies a unique tumor cell type producing multiple hormones in ectopic ACTH and CRH secreting pheochromocytoma

Ectopic Cushing’s syndrome due to ectopic ACTH&CRH-secreting by pheochromocytoma is extremely rare and can be fatal if not properly diagnosed. It remains unclear whether a unique cell type is responsible for multiple hormones secreting. In this work, we performed single-cell RNA sequencing to three different anatomic tumor tissues and one peritumoral tissue based on a rare case with ectopic ACTH&CRH-secreting pheochromocytoma. And in addition to that, three adrenal tumor specimens from common pheochromocytoma and adrenocortical adenomas were also involved in the comparison of tumor cellular heterogeneity. A total of 16 cell types in the tumor microenvironment were identified by unbiased cell clustering of single-cell transcriptomic profiles from all specimens. Notably, we identified a novel multi-functionally chromaffin-like cell type with high expression of both POMC (the precursor of ACTH) and CRH, called ACTH+&CRH + pheochromocyte. We hypothesized that the molecular mechanism of the rare case harbor Cushing’s syndrome is due to the identified novel tumor cell type, that is, the secretion of ACTH had a direct effect on the adrenal gland to produce cortisol, while the secretion of CRH can indirectly stimulate the secretion of ACTH from the anterior pituitary. Besides, a new potential marker (GAL) co-expressed with ACTH and CRH might be involved in the regulation of ACTH secretion. The immunohistochemistry results confirmed its multi-functionally chromaffin-like properties with positive staining for CRH, POMC, ACTH, GAL, TH, and CgA. Our findings also proved to some extent the heterogeneity of endothelial and immune microenvironment in different adrenal tumor subtypes.

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.

Effects of fluorine substitution on substrate conversion by cytochromes P450 17A1 and 21A2

Cytochromes P450 17A1 (CYP7A1) and 21A2 (CYP21A2) catalyze key reactions in the production of steroid hormones, including mineralocorticoids, glucocorticoids, and androgens. With the ultimate goal of designing probes that are selectively metabolized to each of these steroid types, fluorinated derivatives of the endogenous substrates, pregnenolone and progesterone, were prepared to study the effects on CYP17A1 and CYP21A2 activity. In the functional assays, the hydroxylase reactions catalysed by each of these enzymes were blocked when fluorine was introduced at the site of metabolism (positions 17 and 21 of the steroid core, respectively). CYP17A1, furthermore, performed the 17,20-lyase reaction on substrates with a fluorine installed at the 21-position. Importantly, none of the substitutions examined herein prevented compound entry into the active sites of either CYP17A1 or CYP21A2 as demonstrated by spectral binding assays. Taken together, the results suggest that fluorine might be used to redirect the metabolic pathways of pregnenolone and progesterone to specific types of steroids.

Stepwise binding of inhibitors to human cytochrome P450 17A1 and rapid kinetics of inhibition of androgen biosynthesis

Cytochrome P450 (P450) 17A1 catalyzes the 17α-hydroxylation of progesterone and pregnenolone as well as the subsequent lyase cleavage of both products to generate androgens. However, the selective inhibition of the lyase reactions, particularly with 17α-hydroxy pregnenolone, remains a challenge for the treatment of prostate cancer. Here, we considered the mechanisms of inhibition of drugs that have been developed to inhibit P450 17A1, including ketoconazole, seviteronel, orteronel, and abiraterone, the only approved inhibitor used for prostate cancer therapy, as well as clotrimazole, known to inhibit P450 17A1. All five compounds bound to P450 17A1 in a multistep process, as observed spectrally, over a period of 10 to 30 s. However, no lags were observed for the onset of inhibition in rapid-quench experiments with any of these five compounds. Furthermore, the addition of substrate to inhibitor–P450 17A1 complexes led to an immediate formation of product, without a lag that could be attributed to conformational changes. Although abiraterone has been previously described as showing slow-onset inhibition (t_1/2 = 30 min), we observed rapid and strong inhibition. These results are in contrast to inhibitors of P450 3A4, an enzyme with a larger active site in which complete inhibition is not observed with ketoconazole and clotrimazole until the changes are completed. Overall, our results indicate that both P450 17A1 reactions—17α-hydroxylation and lyase activity—are inhibited by the initial binding of any of these inhibitors, even though subsequent conformational changes occur.

Steroidogenic cytochrome P450 17A1 structure and function

Cytochrome P450 17A1 (CYP17A1) is a critical steroidogenic enzyme, essential for producing glucocorticoids and sex hormones. This review discusses the complex activity of CYP17A1, looking at its role in both the classical and backdoor steroidogenic pathways and the complex chemistry it carries out to perform both a hydroxylation reaction and a carbon-carbon cleavage, or lyase reaction. Functional and structural investigations have informed our knowledge of these two reactions. This review focuses on a few specific aspects of this discussion: the identities of reaction intermediates, the coordination of hydroxylation and lyase reactions, the effects of cytochrome b5, and conformational selection. These discussions improve understanding of CYP17A1 in a physiological setting, where CYP17A1 is implicated in a variety of steroidogenic diseases. This information can be used to improve ways in which CYP17A1 can be effectively modulated to treat diseases such as prostate and breast cancer, Cushing's syndrome, and glioblastoma.

The cytochrome P450 (CYP) superfamily in cnidarians

The cytochrome P450 (CYP) superfamily is a diverse and important enzyme family, playing a central role in chemical defense and in synthesis and metabolism of major biological signaling molecules. The CYPomes of four cnidarian genomes (Hydra vulgaris, Acropora digitifera, Aurelia aurita, Nematostella vectensis) were annotated; phylogenetic analyses determined the evolutionary relationships amongst the sequences and with existing metazoan CYPs. 155 functional CYPs were identified and 90 fragments. Genes were from 24 new CYP families and several new subfamilies; genes were in 9 of the 12 established metazoan CYP clans. All species had large expansions of clan 2 diversity, with H. vulgaris having reduced diversity for both clan 3 and mitochondrial clan. We identified potential candidates for xenobiotic metabolism and steroidogenesis. That each genome contained multiple, novel CYP families may reflect the large evolutionary distance within the cnidarians, unique physiology in the cnidarian classes, and/or different ecology of the individual species.

Computing Metal-Binding Proteins for Therapeutic Benefit

Over one third of biomolecules rely on metal ions to exert their cellular functions. Metal ions can play a structural role by stabilizing the structure of biomolecules, a functional role by promoting a wide variety of biochemical reactions, and a regulatory role by acting as messengers upon binding to proteins regulating cellular metal-homeostasis. These diverse roles in biology ascribe critical implications to metal-binding proteins in the onset of many diseases. Hence, it is of utmost importance to exhaustively unlock the different mechanistic facets of metal-binding proteins and to harness this knowledge to rationally devise novel therapeutic strategies to prevent or cure pathological states associated with metal-dependent cellular dysfunctions. In this compendium, we illustrate how the use of a computational arsenal based on docking, classical, and quantum-classical molecular dynamics simulations can contribute to extricate the minutiae of the catalytic, transport, and inhibition mechanisms of metal-binding proteins at the atomic level. This knowledge represents a fertile ground and an essential prerequisite for selectively targeting metal-binding proteins with small-molecule inhibitors aiming to (i) abrogate deregulated metal-dependent (mis)functions or (ii) leverage metal-dyshomeostasis to selectively trigger harmful cells death.

Analysis of astaxanthin molecular targets based on network pharmacological strategies

In order to further explore the potential pharmacological activity of astaxanthin (AST), network pharmacological approaches were employed in this work to systematically investigate its affinity targets, perturbed signaling pathways, and related disease applications. First, potential targets were captured based on AST chemical structure information. Enrichment analysis was then performed using bioinformatics tools to predict the biological processes and diseases in which AST targets are involved. The results suggest that AST is involved in steroid hormone metabolism, and the regulation of glucocorticoids may be one of the potential mechanisms of its known therapeutic effects on depression and insulin resistance. Molecular docking experiments confirmed that AST can form stable binding to several key nodes (SRD5A2, STS, AKR1C2, HSD11B1, and CYP17A1) in steroid hormone biosynthesis. More importantly, the molecular targets of AST were the most significantly associated with endometriosis. Functionally, grouped analysis of key therapeutic nodes was carried out by establishing the interaction network between drug targets and disease targets. While exerting inflammatory effects, the regulation of estrogen and other semiochemicals by targeting steroid metabolism may be the biological basis for the potential treatment of endometriosis with AST. This work provides a theoretical basis for further exploring the pharmacological mechanisms of AST and development of new therapeutic applications. PRACTICAL APPLICATIONS: In this study, systematic pharmacological methods were used to identify the potential therapeutic effects and associated mechanisms of astaxanthin, providing a bioinformatics basis for further exploration of astaxanthin's new pharmacological properties in foods.

Substrate-Specific Allosteric Effects on the Enhancement of CYP17A1 Lyase Efficiency by Cytochrome b5

CYP17A1 is an essential human steroidogenic enzyme, which catalyzes two sequential reactions leading to the formation of androstenedione from progesterone and dehydroepiandrosterone from pregnenolone. The second reaction is the C17-C20 bond scission, which is strongly dependent on the presence of cytochrome b₅ and displays a heretofore unexplained more pronounced acceleration when 17OH-progesteone (17OH-PROG) is a substrate. The origin of the stimulating effect of cytochrome b₅ on C-C bond scission catalyzed by CYP17A1 is still debated as mostly due to either the acceleration of the electron transfer to the P450 oxy complex or allosteric effects of cytochrome b₅ favoring active site conformations that promote lyase activity. Using resonance Raman spectroscopy, we compared the effect of Mn-substituted cytochrome b₅ (Mn-Cytb₅) on the oxy complex of CYP17A1 with both proteins co-incorporated in lipid nanodiscs. For CYP17A1 with 17OH-PROG, a characteristic shift of the Fe-O mode is observed in the presence of Mn-b₅, indicating reorientation of a hydrogen bond between the 17OH group of the substrate from the terminal to the proximal oxygen atom of the Fe-O-O moiety, a configuration favorable for the lyase catalysis. For 17OH-pregnenolone, no such shift is observed, the favorable H-bonding orientation being present even without Mn-Cytb₅. These new data provide a precise allosteric interpretation for the more pronounced acceleration seen for the 17OH-PROG substrate.

Abiraterone and D4, 3-keto Abiraterone binding to CYP17A1, a structural comparison study by molecular dynamic simulation

The importance of computer-aided drug design and development is clear nowadays. These approaches smooth the way of designing some efficient candidates based on drugs in use. At this place, we studied the mechanism of D4-abiraterone (D4A), the active metabolite of Abiraterone (Abi), binding to CYP17A1 compared with Abi. The molecular dynamics simulation results reveal that the metabolite, which lacks the key 3β-OH group, has a varied H-bond forming pattern. The critical H-bond between 3β-OH of Abi with Asn_202 turns to 3 Keto-O of D4A with Arg_239 in the substrate-binding site. This interaction causes a remarkable distance of 0.63 nm between D4A nitrogen and Fe in heme, which reduces its 17,20 lyase selectivity. The D4A keto moiety presents an immense number of H-bond with surrounding solvent molecules compared with the Abi hydroxyl group. As a result, D4A develops a weaker H-bond network with the enzyme. Otherwise, the heterocyclic nature of inhibitors helps for noticeable van der Waals interaction formation with CYP17A1. However, Abi stabilized position in the binding site helps more van der Waals interactions deposition than D4A. These results convinced the importance of the conserved H-bond for acquiring the proper position by the substrate or inhibitor in the binding site.

Charge density analysis of abiraterone acetate

A high-resolution single-crystal X-ray diffraction study of abiraterone acetate (1) has been carried out. The charge density distribution in the crystal of this anticancer drug is reconstructed from experimental data. The nature and the contributions of various intermolecular interactions to the total crystal energy are studied by means of the quantum theory `Atoms-in-Molecules', a non-covalent interactions method and energy framework plots. In general, dispersion C-H...H-C and C-H...π interactions play the main role in crystal packing of 1. The Voronoi tessellation analysis of 1 confirmed that contribution of hydrophobic and hydrophilic interactions to the molecular surface is close to their contribution to the total crystal energy. Similar analysis of abiraterone complexes with the cytochrome P450 family demonstrated that contribution of the C-H...H-C and C-H...π interactions to the molecular surface of the drug remains unchanged to fit the binding pocket, despite the presence of water and heme molecules, and hydrophilic groups within the pocket.

Transcriptomic and biochemical effects of pycnogenol in ameliorating heat stress-related oxidative alterations in rats

BACKGROUND

Heat stress is a condition that is due to extreme heat exposure. It occurs when the body cannot keep its temperature healthy in response to a hot climate and associated with oxidative stress. Testicular hyperthermia can induce apoptosis of sperm cells, affect sperm production and decrease sperm concentration, leading to sperm disorder, for this reason, we examined the protective impact of pycnogenol that it has a wide range of biological benefits, including antioxidant, anti-inflammatory and anti-cancer activities against the oxidative alterations that happen in testicular and brain tissues due to heat stress in rats.

STUDY DESIGN

Forty-eight Wistar male rats, approximately around 6 weeks age were allocated randomly into four groups (12 in each) of control, HS (subjected to heat stress and supplemented orally with 50 mg of pycnogenol/kg b. w./day dissolved in saline for 21 days), and pycnogenol (rats supplemented orally with 50 mg of pycnogenol/kg b. w./day dissolved in saline for 21 days).

RESULTS

Data revealed a promising role of pycnogenol as an antioxidant, natural product to successfully reverse the heat-induced oxidative alterations in testicular and brain tissues of rats through significant upregulation of superoxide dismutase-2, catalase, reduced glutathione, and anti-apoptotic gene, while downregulating pro-apoptotic, and heat shock protein70. Pycnogenol treatment also reversed the reproductive hormone level and spermatogenesis to their normal values.

CONCLUSION

Pycnogenol as a natural protective supplement could recover these heat stress-induced oxidative changes in testes and hypothalamus.

Comparative Dynamics and Functional Mechanisms of the CYP17A1 Tunnels Regulated by Ligand Binding

As an important member of cytochrome P450 (CYP) enzymes, CYP17A1 is a dual-function monooxygenase with a critical role in the synthesis of many human steroid hormones, making it an attractive therapeutic target. The emerging structural information about CYP17A1 and the growing number of inhibitors for these enzymes call for a systematic strategy to delineate and classify mechanisms of ligand transport through tunnels that control catalytic activity. In this work, we applied an integrated computational strategy to different CYP17A1 systems with a panel of ligands to systematically study at the atomic level the mechanism of ligand-binding and tunneling dynamics. Atomistic simulations and binding free energy computations identify the dynamics of dominant tunnels and characterize energetic properties of critical residues responsible for ligand binding. The common transporting pathways including S, 3, and 2c tunnels were identified in CYP17A1 binding systems, while the 2c tunnel is a newly formed pathway upon ligand binding. We employed and integrated several computational approaches including the analysis of functional motions and sequence conservation, atomistic modeling of dynamic residue interaction networks, and perturbation response scanning analysis to dissect ligand tunneling mechanisms. The results revealed the hinge-binding and sliding motions as main functional modes of the tunnel dynamic, and a group of mediating residues as key regulators of tunnel conformational dynamics and allosteric communications. We have also examined and quantified the mutational effects on the tunnel composition, conformational dynamics, and long-range allosteric behavior. The results of this investigation are fully consistent with the experimental data, providing novel rationale to the experiments and offering valuable insights into the relationships between the structure and function of the channel networks and a robust atomistic model of activation mechanisms and allosteric interactions in CYP enzymes.

Slow-, Tight-Binding Inhibition of CYP17A1 by Abiraterone Redefines Its Kinetic Selectivity and Dosing Regimen

Substantial evidence underscores the clinical efficacy of inhibiting CYP17A1-mediated androgen biosynthesis by abiraterone for treatment of prostate oncology. Previous structural analysis and in vitro assays revealed inconsistencies surrounding the nature and potency of CYP17A1 inhibition by abiraterone. Here, we establish that abiraterone is a slow-, tight-binding inhibitor of CYP17A1, with initial weak binding preceding the subsequent slow isomerization to a high-affinity CYP17A1-abiraterone complex. The in vitro inhibition constant of the final high-affinity CYP17A1-abiraterone complex ( ( K _i * = 0.39 nM )yielded a binding free energy of -12.8 kcal/mol that was quantitatively consistent with the in silico prediction of -14.5 kcal/mol. Prolonged suppression of dehydroepiandrosterone (DHEA) concentrations observed in VCaP cells after abiraterone washout corroborated its protracted CYP17A1 engagement. Molecular dynamics simulations illuminated potential structural determinants underlying the rapid reversible binding characterizing the two-step induced-fit model. Given the extended residence time (42 hours) of abiraterone within the CYP17A1 active site, in silico simulations demonstrated sustained target engagement even when most abiraterone has been eliminated systemically. Subsequent pharmacokinetic-pharmacodynamic (PK-PD) modeling linking time-dependent CYP17A1 occupancy to in vitro steroidogenic dynamics predicted comparable suppression of downstream DHEA-sulfate at both 1000- and 500-mg doses of abiraterone acetate. This enabled mechanistic rationalization of a clinically reported PK-PD disconnect, in which equipotent reduction of downstream plasma DHEA-sulfate levels was achieved despite a lower systemic exposure of abiraterone. Our novel findings provide the impetus for re-evaluating the current dosing paradigm of abiraterone with the aim of preserving PD efficacy while mitigating its dose-dependent adverse effects and financial burden. SIGNIFICANCE STATEMENT: With the advent of novel molecularly targeted anticancer modalities, it is becoming increasingly evident that optimal dose selection must necessarily be predicated on mechanistic characterization of the relationships between target exposure, drug-target interactions, and pharmacodynamic endpoints. Nevertheless, efficacy has always been perceived as being exclusively synonymous with affinity-based measurements of drug-target binding. This work demonstrates how elucidating the slow-, tight-binding inhibition of CYP17A1 by abiraterone via in vitro and in silico analyses was pivotal in establishing the role of kinetic selectivity in mediating time-dependent CYP17A1 engagement and eventually downstream efficacy outcomes.

CYP17A1 Polymorphisms Are Linked to the Risk of Coronary Heart Disease in a Case-Control Study

BACKGROUND

Cytochrome P450 17A1 (CYP17A1) catalyzes the formation and metabolism of steroid hormones and is required for cortisol and androgens. There is increasing evidence that CYP17A1 plays an important role in the development of coronary heart disease (CHD). However, the association of CYP17A1 polymorphisms and CHD susceptibility is still not clear.

METHODS

We conducted a case-control study with 396 CHD cases and 461 healthy controls from Hainan province, China. Using the Agena MassARRAY platform, we genotyped 4 genetic variants (rs3740397, rs1004467, rs4919687, and rs3781286) in CYP17A1. Logistic regression analysis was used to assess the association of CYP17A1 polymorphisms with CHD risk by odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

It showed that A allele of CYP17A1 rs4919687 carried with a 1.59-fold increased risk of CHD (OR = 1.59; 95% CI = 1.26-1.99; P < 0.001). Also, rs4919687 was significantly associated with CHD risk under various models (homozygote: OR = 3.60; 95% CI = 1.64-7.83; P = 0.001; dominant: OR = 1.51; 95% CI = 1.06-2.13; P = 0.021; recessive: OR = 3.28; 95% CI = 1.51-7.14; P = 0.003; additive: OR = 1.56; 95% CI = 1.17-2.07; P = 0.002). Moreover, analysis showed that Ars1004467 Ars4919687 haplotype was a protective factor of CHD (OR = 0.64; 95% CI = 0.48-0.86; P = 0.002).

CONCLUSIONS

Our study suggests that CYP17A1 polymorphisms are associated with CHD susceptibility in the Hainan Han Chinese population.

Alternative modes of O2 activation in P450 and NOS enzymes are clarified by DFT modeling and resonance Raman spectroscopy

The functions of heme proteins are modulated by hydrogen bonds (H-bonds) directed at the heme-bound ligands by protein residues. When the gaseous ligands CO, NO, or O2 are bound, their activity is strongly influenced by H-bonds to their atoms. These H-bonds produce characteristic changes in the vibrational frequencies of the heme adduct, which can be monitored by resonance Raman spectroscopy and interpreted with density functional theory (DFT) computations. When the protein employs a cysteinate proximal ligand, bound O2 becomes particularly reactive, the course of the reaction being controlled by H-bonding and proton delivery. In this work, DFT modeling is used to examine the effects of H-bonding to either the terminal (Ot) or proximate (Op) atom of methylthiolate-Fe(II)porphine-O2, as well as to the thiolate S atom. H-bonds to Op produce a positive linear correlation between ν(Fe - O) and ν(O - O), because they increase the sp2 character of Op, weakening both the Fe - O and O - O bonds. H-bonds to Ot produce a negative correlation, because they increase Fe backbonding, strengthening the Fe - O but weakening the O - O bond. Available experimental data accommodate well to the computed pattern. In particular, this correspondence supports the interpretation of cytochrome P450 data by Kincaid and Sligar [M. Gregory, P.J. Mak, S.G. Sligar, J.R. Kincaid, Angew. Chem. Int. Ed. 125 (2013) 5450-5453], involving steering between hydroxylation and lyase reaction channels by differential H-bonds. Similar channeling between the first and second steps of the nitric oxide synthase reaction is likely.

CYP17A1 exhibits 17αhydroxylase/17,20-lyase activity towards 11β-hydroxyprogesterone and 11-ketoprogesterone metabolites in the C11-oxy backdoor pathway

Cytochrome P450 17α-hydroxylase/17,20-lyase (CYP17A1) plays a pivotal role in the regulation of adrenal and gonadal steroid hormone biosynthesis. More recent studies highlighted the enzyme's role in the backdoor pathway leading to androgen production. Increased CYP17A1 activity in endocrine disorders and diseases are associated with elevated C₂₁ and C₁₉ steroids which include 17α-hydroxyprogesterone and androgens, as well as C11-oxy C₂₁ and C11-oxy C₁₉ steroids. We previously reported that 11β-hydroxyprogesterone (11OHP4), 21-deoxycortisol (21dF) and their keto derivatives are converted by 5α-reductases and hydroxysteroid dehydrogenases yielding C₁₉ steroids in the backdoor pathway. In this study the 17α-hydroxylase and 17,20-lyase activity of CYP17A1 towards the unconventional C11-oxy C₂₁ steroid substrates and their 5α- and 3α,5α-reduced metabolites was investigated in transfected HEK-293 cells. CYP17A1 catalysed the 17α-hydroxylation of 11OHP4 to 21dF and 11-ketoprogesterone (11KP4) to 21-deoxycortisone (21dE) with negligible hydroxylation of their 5α-reduced metabolites while no lyase activity was detected. The 3α,5α-reduced C11-oxy C₂₁ steroids-5α-pregnan-3α,11β-diol-20-one (3,11diOH-DHP4) and 5α-pregnan-3α-ol-11,20-dione (alfaxalone) were rapidly hydroxylated to 5α-pregnan-3α,11β,17α-triol-20-one (11OH-Pdiol) and 5α-pregnan-3α,17α-diol-11,20-dione (11K-Pdiol), with the lyase activity subsequently catalysing to conversion to the C11-oxy C₁₉ steroids, 11β-hydroxyandrosterone and 11-ketoandrosterone, respectively. Docking of 11OHP4, 11KP4 and the 5α-reduced metabolites, 5α-pregnan-11β-ol-3,20-dione (11OH-DHP4) and 5α-pregnan-3,11,20-trione (11K-DHP4) with human CYP17A1 showed minimal changes in the orientation of these C11-oxy C₂₁ steroids in the active pocket when compared with the binding of progesterone suggesting the 17,20-lyase is impaired by the C11-hydroxyl and keto moieties. The structurally similar 3,11diOH-DHP4 and alfaxalone showed a greater distance between C17 and the heme group compared to the natural substrate, 17α-hydroxypregnenolone potentially allowing more orientational freedom and facilitating the conversion of the C11-oxy C₂₁ to C11-oxy C₁₉ steroids. In summary, our in vitro assays showed that while CYP17A1 readily hydroxylated 11OHP4 and 11KP4, the enzyme was unable to catalyse the 17,20-lyase reaction of these C11-oxy C₂₁ steroid products. Although CYP17A1 exhibited no catalytic activity towards the 5α-reduced intermediates, once the C4-C5 double bond and the keto group at C3 were reduced, both the hydroxylation and lyase reactions proceeded efficiently. These findings show that the C11-oxy C₂₁ steroids could potentially contribute to the androgen pool in tissue expressing steroidogenic enzymes in the backdoor pathway.

Pregnenolonyl-α-glucoside exhibits marked anti-cancer and CYP17A1 enzymatic inhibitory activities

We report here that pregnenolonyl-α-glucoside (2), a steryl glycoside synthesized directly from pregnenolone and glucose via a consecutive multienzyme-catalyzed process, exhibits marked dose-dependent cytotoxic activity against HT29, AGS, and ES-2 cells with IC50 values of 23.5 to 50.9 μM. An in vitro CYP17A1 binding pattern assay and protein-ligand docking model support that 2, like abiraterone, binds in the active site heme iron pocket of CYP17A1.

The Biosynthesis of Enzymatically Oxidized Lipids

Enzymatically oxidized lipids are a specific group of biomolecules that function as key signaling mediators and hormones, regulating various cellular and physiological processes from metabolism and cell death to inflammation and the immune response. They are broadly categorized as either polyunsaturated fatty acid (PUFA) containing (free acid oxygenated PUFA "oxylipins", endocannabinoids, oxidized phospholipids) or cholesterol derivatives (oxysterols, steroid hormones, and bile acids). Their biosynthesis is accomplished by families of enzymes that include lipoxygenases (LOX), cyclooxygenases (COX), cytochrome P450s (CYP), and aldo-keto reductases (AKR). In contrast, non-enzymatically oxidized lipids are produced by uncontrolled oxidation and are broadly considered to be harmful. Here, we provide an overview of the biochemistry and enzymology of LOXs, COXs, CYPs, and AKRs in humans. Next, we present biosynthetic pathways for oxylipins, oxidized phospholipids, oxysterols, bile acids and steroid hormones. Last, we address gaps in knowledge and suggest directions for future work.

Prospective computational design and in vitro bio-analytical tests of new chemical entities as potential selective CYP17A1 lyase inhibitors

The development and advancement of prostate cancer (PCa) into stage 4, where it metastasize, is a major problem mostly in elder males. The growth of PCa cells is stirred up by androgens and androgen receptor (AR). Therefore, therapeutic strategies such as blocking androgens synthesis and inhibiting AR binding have been explored in recent years. However, recently approved drugs (or in clinical phase) failed in improving the expected survival rates for this metastatic-castration resistant prostate cancer (mCRPC) patients. The selective CYP17A1 inhibition of 17,20-lyase route has emerged as a novel strategy. Such inhibition blocks the production of androgens everywhere they are found in the body. In this work, a three dimensional-quantitative structure activity relationship (3D-QSAR) pharmacophore model is developed on a diverse set of non-steroidal inhibitors of CYP17A1 enzyme. Highly active compounds are selected to define a six-point pharmacophore hypothesis with a unique geometrical arrangement fitting the following description: two hydrogen bond acceptors (A), two hydrogen bond donors (D) and two aromatic rings (R). The QSAR model showed adequate predictive statistics. The 3D-QSAR model is further used for database virtual screening of potential inhibitory hit structures. Density functional theory (DFT) optimization provides the electronic properties explaining the reactivity of the hits. Docking simulations discovers hydrogen bonding and hydrophobic interactions as responsible for the binding affinities of hits to the CYP17A1 Protein Data Bank structure. 13 hits from the database search (including five derivatives) are then synthesized in the laboratory as different scaffolds. Ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) in vitro experiments reveals three new chemical entities (NCEs) with half maximal inhibitory concentration (IC₅₀) values against the lyase route at mid-micromolar range with favorable selectivity to the lyase over the hydroxylase route (one of them with null hydroxylase inhibition). Thus, prospective computational design has enabled the design of potential lead lyase-selective inhibitors for further studies.