Natural Steroids Research Articles

Gut Bacteria Metabolize Natural and Synthetic Steroid Hormones via the Reductive OsrABC Pathway.

Steroid hormone metabolism by the gut microbiome has multiple implications for mammalian physiology, but the underlying mechanisms and broader significance of this activity remains largely unknown. Here, we isolate a novel human gut bacterium, Clostridium steroidoreducens T strain HCS.1, that reduces cortisol, progesterone, testosterone, and related steroid hormones to 3β,5β-tetrahydrosteroid products. Through transcriptomics and heterologous enzyme profiling, we identify and biochemically characterize the C. steroidoreducens OsrABC reductive steroid hormone pathway. OsrA is a 3-oxo-Δ 1 -steroid hormone reductase that selectively targets the Δ 1 -bond present in synthetic steroid hormones, including the anti-inflammatory corticosteroids prednisolone and dexamethasone. OsrB is a promiscuous 3-oxo-Δ 4 -steroid hormone reductase that converts steroid hormones to 5β-dihydrosteroid intermediates. OsrC is a 3-oxo-5β-steroid hormone oxidoreductase that reduces 5β-intermediates to 3β,5β-tetrahydro products. We find that osrA and osrB homologs predict steroid hormone reductase activity in diverse gut bacteria and are enriched in Crohn's disease fecal metagenomes. These studies thus identify the basis of reductive steroid hormone metabolism in the gut and establish a link between inflammatory disease and microbial enzymes that deplete anti-inflammatory corticosteroids.

7395 Developmental Programming: Adverse Effects Of Prenatal Exposure To A Real-Life Environmental Chemical Mixture Via Biosolids On Ovarian Folliculogenesis In Adult Sheep

Abstract Disclosure: Y. Zhou: None. K.M. Halloran: None. M. Bellingham: None. N.P. Evans: None. R.G. Lea: None. K.D. Sinclair: None. V. Padmanabhan: None. The ovarian capacity to provide fertilizable oocytes, regulate folliculogenesis as well as activate and progress primordial follicles into preovulatory follicles are key contributing factors to female fertility and reproductive aging. In sheep, as in humans, while genetics play a role in establishing the ovarian reserve during fetal development, developmental insults such as inappropriate exposure to native steroids or environmental chemicals (ECs) can adversely impact the establishment of the ovarian reserve and, additionally can affect folliculogenesis. Considering humans are exposed to multiple ECs simultaneously which could have additive, synergistic, or antagonistic effects, real-life EC exposure models are needed to assess risks posed by EC exposure. Offspring from sheep grazed on biosolids-treated pasture offers one such real-life exposure model. Studies with day 140 fetuses found maternal exposure to a real-life EC mixture via biosolids increased the proportion of unhealthy transitory follicles (Lea et al., Sci Rep. 2016;6:22279). The present study tested if biosolids exposure during fetal life would impact folliculogenesis, follicle activation and follicle atresia during their adult life. Ovaries were derived from adult EasyCare ewes (age 31.4 ± 0.5 months) whose mothers were grazed on biosolids-treated (BTP, n=10) or inorganic fertilizer-treated (Control, n=10) pastures from preconception through to birth. Ovarian morphometry was undertaken to assess the distribution and health status of follicles. Follicular atresia was evaluated via the expression of Caspase-3, an apoptosis marker. Data analysis utilized Student's t-test for normally distributed variables and Mann-Whitney U tests for non-parametric comparisons. There were no differences in the absolute counts or the percentages of follicle classes at all stages of folliculogenesis, the density of primordial follicles in cortical tissue, or the follicular activation rate. An increase in the percentage of unhealthy activated follicles (post-primordial) was noted in the BTP group (p = 0.014), predominantly in the transitory stage (p = 0.021). Consistent with this, a higher density of Caspase-3 positive primary follicles was observed in the BTP group (p = 0.033). These findings indicate the adverse impacts of fetal exposure to an EC mixture via maternal biosolid exposure on the survival of early-stage activated follicles in adult sheep. The lack of difference in ovarian reserve between the control and BTP groups suggests compensatory mechanisms may be in place to prevent premature depletion of the ovarian reserve. Whether EC mixture exposure via biosolids also has an adverse effect on the quality of the surviving activated follicles remains to be determined. Funding source: NIH R01 ES030374. Presentation: 6/3/2024

Unraveling the role of EPHA2 in regulating migration and immunomodulation processes in cervical cancer: exploring the synergic effect of 17β-estradiol on cancer progression.

Cervical cancer remained among the most prevalent cancers in women. Erythropoietin-producing hepatocellular A2 (EPHA2) is overexpressed in many cancers, including cervical cancer, and the mechanism by which it regulates cervical cancer progression is not yet fully understood. Exosomes are extracellular vesicles that carry information in the form of biomolecules, deliver it to the recipient cell, and play a vital role in cellular communication. 17β-Estradiol is the natural female steroid hormone with the greatest estrogenic activity, and it induces cell death in cancer. In this study, we investigated the function of EPHA2 in cervical cancer migration and immunomodulation and the presence of EPHA2 in the cervical cancer serum-derived exosome. A knockdown of EPHA2 (KD-EPHA2) in cervical cancer reduces cancer cell migration by regulating the CD113/Ezrin pathway. Furthermore, EPHA2 exhibited significant involvement in immunomodulation by orchestrating IL-6-mediated signalling cascades, including the AKT-mTOR and JAK-STAT pathways. Immune infiltration analysis revealed a correlation between EPHA2 expression in cervical cancer and the infiltration of various immune cell populations. KD-EPHA2 enhances the 17β-Estradiol inhibitory effect on cell proliferation and migration during cancer progression. In summary, our study revealed that EPHA2 is overexpressed in cervical cancer and plays a vital role in cancer cell migration and immunomodulation, and 17β-Estradiol, along with KD-EPHA2, enhances the inhibitory effect on cancer cell migration and proliferation.

Tyramine Derivatives as Versatile Pharmacophores With Potent Biological Properties: Sex Hormone-Binding Globulin Inhibition, Colon Cancer Antimigration, and Antimicrobial Activity.

Guided by the idea that the presence of a heterocyclic aromatic core and tyramine moiety, under the umbrella of a single molecular scaffold could bring interesting biological properties, herein we present synthesis, characterization, with two crystal structures reported, and biological evaluation of some tyramine derivates. Cytotoxic and antimigratory potential was addressed by using a colorectal cancer cell line as a model system. Although possessing no cytotoxic effects, two compounds have shown strong antimigratory potential in low doses, with no effect on healthy MRC-5 cells. Evaluation of their antimicrobial activities suggested prominent antimicrobial activity, where Compound 4 outperformed streptomycin against Escherichia coli and Proteus mirabilis. Hormone-dependent types of cancer, such as prostate, ovary, and breast, are highly dependent on human sex hormone-binding globulin (SHBG) blood levels. A molecular docking study has shown that 1 has high affinity to bind and therefore compete with natural steroids for the SHBG steroid-binding site. DNA-binding study have shown that 4 interacts with CT-DNA in a groove-binding mode. In silico ADME/T study revealed that all compounds have suitable physicochemical properties for oral bioavailability and druglikeness, while toxicity tests for 1, 4, and 6 suggested potential for mutagenicity (4, 6), hepatotoxicity (6), and skin sensation (1).

Design, Synthesis, Anti-TMV Activity, and Structure-Activity Relationships of Seco-pregnane C21 Steroids and Their Derivatives.

seco-pregnane C21 steroids exhibit high antiviral activity against the tobacco mosaic virus (TMV). However, the structural modification of seco-pregnane C21 steroids and the structure-activity relationship (SAR) of the modified compounds remain unevaluated. Hence, the present study investigated how variations in the original skeletons of natural seco-pregnane C21 steroids affect their antiviral activity. A series of glaucogenin C and A derivatives were designed and synthesized for the first time, and their anti-TMV activity was evaluated. Bioassay results showed that most of the newly designed derivatives exhibited good to excellent antiviral activity; among these derivatives, 5g, 5j, and 5l with higher antiviral activity than that of ningnanmycin emerged as new antiviral candidates. Reverse transcription-polymerase chain reaction and Western blotting assay revealed reduced levels of TMV coat protein (TMV-CP) gene transcription and TMV-CP protein expression, which confirmed the antiviral activity of these derivatives. These compounds also downregulated the expression of NtHsp70-1 and NtHsp70-061. Computational simulations indicated that 5l displayed strong van der Waals energy and electrostatic with the TMV coat protein, affording a lower binding energy (ΔGbind = -56.2 kcal/mol) compared with Ribavirin (ΔGbind = -47.6 kcal/mol). The SAR of these compounds was also evaluated, which demonstrated for the first time that substitutions at C-3 and double bonds of C-5/C-6 and C-13/C-18 are crucial for maintaining high anti-TMV activity.

Ligand-binding characteristics of CYP51 Mycobacterium tuberculosis in relation to marine steroid compounds

CYP51 steroid-14α-demethylases are members of a large superfamily of cytochrome P450 enzymes found in all kingdoms of living organisms, and catalyze the 14α-demethylation reaction of a number of natural steroids, including lanosterol, obtusifoliol, and 24,25-dihydrolanosterol. CYP51 are important components of the eukaryotic steroid biosynthetic chain, and thus represent one of the main targets for antifungal therapy. A 14α-demethylase CYP51 homologous gene has also been found in the genome of Mycobacterium tuberculosis. At the same time, M. tuberculosis lacks the de novo pathway for steroid biosynthesis. Conservation of CYP51 among the Mycobacterium genus and colocalization in the genome with 3Fe-4S ferredoxin Rv0763c, which maintains its catalytic activity in vitro, may indirectly indicate the involvement of MTCYP51 in a biochemical process important for mycobacteria. In order to characterize the specificity of the MTCYP51 active site to various compounds of isoprenoid nature, we obtained a highly purified MTCYP51 and, using spectrophotometric titration and surface plasmon resonance methods, studied the interaction of MTCYP51 with steroids from marine organisms obtained in the Pacific Institute of Bioorganic Chemistry of the Far Eastern Branch of the Russian Academy of Sciences. The investigated compounds represent a wide range of evolutionarily ancient isoprenoids. The results showed that MTCYP51 is able to bind structurally diverse steroid derivatives in the active site. The conducted studies suggest the biological role of MTCYP51 for pathogenic mycobacteria, which consists in the binding and possible metabolism of exogenous bioregulatory isoprenoids in vivo.

Ubiquity and ecological risks of conjugated steroids cannot be overlooked: First evidence from estuarine sediments

Steroids, renowned for endocrine-disrupting capabilities, have garnered significant research interest, predominantly centered on their parent forms. This study was the first to explore the composition, spatiotemporal characteristics, sources, mass inventories, and ecological risks of steroids in free and conjugated forms in estuarine sediments. Seventeen steroids were identified in sediments with the total levels of 1.3–4.3 ng/g. Most natural steroids and metabolites existed in free forms, while synthetic ones predominantly stored in conjugates. Environmental factors exerted limited impacts on steroid distribution. Raw domestic wastewater, drug consumption, and mariculture may be leading steroid sources in estuarine sediments, with total mean mass inventories of 177–219 μg/m2. The predominant contributors to the ecological risk were cortisol, prednisolone, 20α-dihydroprogesterone, 20β-dihydroprogesterone, and progesterone. This research gives the first insight into the understanding of conjugated steroids in the marine environment, and advocates for more studies on the fate and ecotoxicology of conjugated steroids.

Lack of membrane sex steroid receptors for mediating rapid endocrine responses in molluscan nervous systems.

Despite the lack of endogenous synthesis and relevant nuclear receptors, several papers have been published over the decades claiming that the physiology of mollusks is affected by natural and synthetic sex steroids. With scant evidence for the existence of functional steroid nuclear receptors in mollusks, some scientists have speculated that the effects of steroids might be mediated via membrane receptors (i.e. via non-genomic/non-classical actions) -a mechanism that has been well-characterized in vertebrates. However, no study has yet investigated the ligand-binding ability of such receptor candidates in mollusks. The aim of the present study was to further trace the evolution of the endocrine system by investigating the presence of functional membrane sex steroid receptors in a mollusk, the great pond snail (Lymnaea stagnalis). We detected sequences homologous to the known vertebrate membrane sex steroid receptors in the Lymnaea transcriptome and genome data: G protein-coupled estrogen receptor-1 (GPER1); membrane progestin receptors (mPRs); G protein-coupled receptor family C group 6 member A (GPRC6A); and Zrt- and Irt-like protein 9 (ZIP9). Sequence analyses, including conserved domain analysis, phylogenetics, and transmembrane domain prediction, indicated that the mPR and ZIP9 candidates appeared to be homologs, while the GPER1 and GPRC6A candidates seemed to be non-orthologous receptors. All candidates transiently transfected into HEK293MSR cells were found to be localized at the plasma membrane, confirming that they function as membrane receptors. However, the signaling assays revealed that none of the candidates interacted with the main vertebrate steroid ligands. Our findings strongly suggest that functional membrane sex steroid receptors which would be homologous to the vertebrate ones are not present in Lymnaea. Although further experiments are required on other molluscan model species as well, we propose that both classical and non-classical sex steroid signaling for endocrine responses are specific to chordates, confirming that molluscan and vertebrate endocrine systems are fundamentally different.

Investigation of the Physiological and Post‐training Effects of Ecdysteroid Supplementation by Multivariate Analysis of the Human Serum Metabolome

ABSTRACTThis work aims to characterize the serum profile of athletes after the administration of ecdysteroids, natural steroid hormones recently reported to enhance athletic performance. The combination of mass spectrometry and chemometric tools may allow to differentiate physiological effects from post‐training and intake‐driven effects. Serum samples were collected from 46 healthy male volunteers and divided into four groups: control (two capsules/day of Peak Ecdysone without training), placebo (two capsules without ecdysteroids with training), Ec1 (two capsules/day Peak Ecdysone with training), and Ec2 (eight capsules/day Peak Ecdysone with training). Metabolic profiling was measured using a SCIEX Triple Quadrupole LC‐MS/MS system coupled with the Biocrates AbsoluteIDQ p180 kit, which allows quantitation of a large panel of metabolites that were subjected to multivariate analysis. Unsupervised analysis of the data found no significant differences between the placebo and the ecdysteroid supplementation groups. By merging Ec1 and Ec2 into a single group, coded as treated, a clear discrimination between the control and placebo groups was observed. Phosphatidylcholines were among the most significant features of ecdysteroids administration, showing a dose‐dependent effect in Ec1 and Ec2 groups. As specific metabolic phenotypes can result from years of training, the discrimination of physiological effects from those caused by the administration of banned substances can be a valuable analytical strategy for the interpretation of adverse analytical findings in the anti‐doping field.

Efficient genome engineering in Mycolicibacterium neoaurum using Cas9 from Streptococcus thermophilus.

Non-pathogenic mycobacteria, including Mycolicibacterium neoaurum, can directly utilize phytosterols for large-scale industrial production of steroid medicine intermediates due to their natural steroid metabolism pathway. The targeted genetic modification of M. neoaurum is conducive to the selection of high-yield engineering bacteria with high-value-added product, such as Pregnadien-20-carboxylic acid (PDC), which is an important precursor for synthesizing some corticosteroids. Based on heterologous type II CRISPR/sth1Cas9 system, a simple strategy was developed to genetic engineer M. neoaurum genome. Here, a customizable plasmid tool pMSC9 was constructed from pMV261 with integration of sth1Cas9 protein and corresponding sgRNA scaffold. Subsequently, the pMSC9 was inserted with spacer sequences corresponding to different targeted genes, generating editing plasmids, and then transformed into M. neoaurum. As a result, the targeted genes were introduced with DNA double stand breaks (DSBs) by CRISPR/sth1Cas9 system and then repaired by innate non-homologous end-joining (NHEJ) mechanism. Finally, editing plasmids were cured from correctly edited M. neoaurum mutants by means of no resistance cultivation, and the resulting mutant deleting the one target gene was used as the host to which another target gene could be deleted via the same process. This study demonstrated that the CRISPR/sth1Cas9 tool allowed M. neoaurum strains to be rapidly edited. And the editing mode of CRISPR/sth1Cas9 system indicated that this tool was an important supplement to the gene editing toolbox of M. neoaurum.

Dioscin attenuates lupus nephritis in NZB/W F1 mice by decreasing NF-κB activation and NLRP3 inflammasome.

Dioscin, a natural steroid saponin, has anticancer, anti-inflammatory, anti-hyperlipidemic, and glycemic capabilities. This study focused on dioscin roles and its related mechanisms in experimental lupus nephritis. Lupus-prone NZB/W F1 mice were intragastrically administered with dioscin, prednisone or vehicle, and kidney, urine and blood samples were harvested after the mice were sacrificed. Proteinuria, blood urea nitrogen (BUN), creatinine, anti-dsDNA, IL-1β, and IL-18 levels in serum as well as IFN-γ, IL-6, IL-17 and TNF-α levels in kidney tissues were assessed. Renal histopathology was examined through hematoxylin-eosin staining. IgG and C3 expression in kidney was evaluated using immunofluorescence staining. The number of glomerular F4/80-positive cells and NLRP3-positive cells was determined by immunohistochemical staining. The protein expression was examined by western blotting. Dioscin alleviated lupus nephritis in NZB/W F1 mice. Dioscin declined serum anti-dsDNA level, prevented deposition of immune complexes in renal glomeruli, and inhibited the inflammatory response and infiltration of macrophages into mouse kidneys. Dioscin inhibited NF-κB and NLRP3 inflammasome in NZB/W F1 mice. Dioscin ameliorates lupus nephritis through inhibition of NLRP3 inflammasome and NF-κB signaling.

Synthesis and Pharmacological Properties of Modified A- and D-Ring in Dehydroepiandrosterone (DHEA): A Review.

Dehydroepiandrosterone (3β-hydroxyandrost-5-en-17-one) (DHEA) is a naturally occurring steroid hormone primarily produced in the zona reticularis of the human adrenal glands. It serves as a crucial precursor for sex hormones, such as testosterone, estradiol, and androstenedione. Recent findings indicate that DHEA serves as the primary source of sex steroids in women during both pre- and postmenopausal stages. Additionally, a decline in DHEA levels with age is linked to various hormone-deficiency symptoms. Despite the wide array of biological activities that make DHEA a valuable polycyclic natural steroid, particularly for pharmaceutical and cosmetic applications, reports suggest that oral DHEA has limited clinical effect. Thus, A- and D-ring modified DHEA are synthesized and their biological activities are carried out by different research groups and enhanced biological activity reported in the literature. Here, in this review, we have tried to cover all of the synthetic routes and biological studies of modified A- and D-ring DHEA from 2015 to mid-2022.

Improving the Solubility and Bioavailability of Progesterone Cocrystals with Selected Carboxylic Acids.

Progesterone (PROG) is a natural steroid hormone with low solubility and high permeability that belongs to biopharmaceutics classification system class II. In this study, novel pharmaceutical cocrystals of PROG were successfully prepared by solvent evaporation or a liquid-assisted grinding process aimed at enhancing its solubility and bioavailability. The cocrystal formers selected based on crystal engineering principles were carboxylic acids, namely, 4-formylbenzeneboronic acid (BBA), isophthalic acid (IPA), and 3-nitrophthalic acid (NPA). The cocrystal structures were characterized using multiple techniques. Single-crystal X-ray diffraction results showed that the carbonyl group, acting as a hydrogen bond acceptor, was pivotal in the cocrystal network formation, with C-H···O interactions further stabilizing the crystals. The cocrystals exhibited improved solubility and dissolution profiles in vitro, with no significant changes in hygroscopicity. The parallel artificial membrane permeability assay (PAMPA) models indicated that the cocrystals retained PROG's high permeability. Pharmacokinetic studies in Sprague-Dawley rats revealed that all cocrystals increased PROG exposure, with AUC(0~∞) values for PROG-BBA, PROG-IPA, and PROG-NPA being 742.59, 1201.72 and 442.67 h·ng·mL-1, respectively. These values are substantially higher compared to free PROG, which had an AUC(0~∞) of 301.48 h·ng·mL-1. Notably, PROG-IPA provided the highest AUC improvement, indicating a significant enhancement in bioavailability. Collectively, the study concludes that the cocrystal approach is a valuable strategy for optimizing the physicochemical properties and oral bioavailability of PROG, with potential implications for the development of other poor water-soluble drugs.

CORTICOSTEROID-INDUCED EXPRESSION OF MICROBIAL VIRULENCE CAN ENHANCE THE DEVELOPMENT OF HOST INFECTIOUS DISEASE

Corticosteroids regulate a number of physiological processes and are synthetic analogs of the natural steroid hormones produced by the adrenal cortex. As drugs, corticosteroids are non-inflammatory and are used for the treatment of plethora of conditions which include arthritis, kidney, skin, lungs or thyroid disorders, for the treatment and relief of symptoms of allergies and symptoms of some gastrointestinal disorders. In addition, glucocorticoids can regulate the effects of inflammatory disorders, including sepsis, autoimmune diseases, and allergies. These conditions are potentially fatal. Consequently, this drug class is among the most commonly prescribed globally. One representative of corticosteroid class of drugs is dexamethasone which is used to treat allergies, adrenal problems, arthritis, asthma, diseases of blood or bone marrow, inflammation, kidney diseases, different types of skin conditions, and episodes of multiple sclerosis. Virulence factors help bacteria colonize the host at the level of the cell. In their nature, these factors are secretory, associated with the membrane or present in the cytosol. Secretory factors allow bacterium to circumvent the host immune response, while membrane factors aid bacterium in adhesion to the host cell. Finally, cytosol factors help bacteria adapt metabolically, physiologically, and morphologically to their changing environment. One such factor is aspartyl proteinase, a protein that degrades other proteins and is a virulence factor in many pathogens playing a role in the host invasion process. Another important virulence factor is the ability to form biofilms, which can render bacteria resistant to antimicrobials. Despite the widespread use of corticosteroids, including dexamethasone, little is known about their possible influence on the expression of virulence factors such as aspartyl proteinase. If such a connection is to exist the use of corticosteroids could elicit pathogenesis in certain microbes. In the here-presented study we wanted to investigate the effects of dexamethasone on the growth, expression of aspartyl proteinase and biofilm formation in three E. coli strains that were previously isolated from patients suffering from urinary tract infection. To this aim, we amended the growth media with 0.5 mg/mL dexamethasone. Bacterial growth was measured over the period of 24 hours and the effect of dexamethasone was established at different time points. Administration of 0.5 mg/mL glucocorticoid drug dexamethasone did not significantly affect bacterial growth. However, it resulted in an increase in concentration of secreted E. coli virulence factor aspartyl proteinase, which increased up to 2.6-fold for some E. coli strains. In addition, we noted the increased biofilm formation in to three out of four studied strains. This study indicates dexamethasone as a possible trigger molecule for the expression of virulence factor aspartyl proteinase in E. coli.

P03 Anti-ageing effects of oestetrol on the skin: protection from cellular senescence and restoration of dermal architecture

Abstract Introduction and aims Skin is a major endocrine organ, undergoing profound structural and functional alterations in response to hormonal changes. Postmenopause, the rapid decline in circulating 17β-oestradiol (E2) leads to skin ageing, while exogenous E2 administration restores skin function, promoting the regenerative capacity of aged skin. Nevertheless, the risk of off-target effects limits the clinical use of E2 for skin indications. Oestetrol (E4), a natural oestrogenic steroid currently undergoing clinical trials as a hormone replacement therapy, presents a favourable safety profile and could be a suitable alternative to E2. However, as no studies have investigated the effects E4 on skin ageing, the aim of this study was to evaluate the potential of E4 to overcome effects of skin ageing. Methods Micro-osmotic pumps were subcutaneously implanted into 14-month-old female mice, allowing sustained systemic delivery of E2 or E4 over 3 weeks. Reversal of skin ageing was assessed via noninvasive skin parameter testing, histological analysis and biomechanics. Aged human dermal fibroblasts were treated with E4 to measure effects on the extracellular matrix deposition (ECM) in vitro. Finally, human keratinocytes were treated with E4 prior to inducing senescence to assess potential protective effects against skin ageing. Readouts included senescence-associated beta galactosidase staining, immunofluorescence and quantitative polymerase chain reaction. Results Systemic administration of E4 reversed multiple characteristics of skin ageing. E4 treatment significantly increased skin hydration, stimulated collagen deposition and elevated elastic fibre synthesis. These structural changes improved the biomechanical function of skin, increasing breaking strength and elasticity. In vitro studies confirmed direct anti-ageing activity on multiple cell types. E4 substantially increased ECM deposition in aged human dermal fibroblasts and protected against senescence induction in human keratinocytes. Conclusions Collectively, these preclinical data demonstrate significant beneficial effects of E4 on aged skin, strongly supporting future clinical evaluation of E4 to alleviate the effects of skin ageing following menopause.

Brassinosteroids: Relevant Evidence Related to Mitigation of Abiotic and Biotic Stresses in Plants

Extreme events of climate change are increasing, such as droughts and heat waves, causing limitations on growth and yield in relevant food crops, as well as threatening global food security. Brassinosteroids (BRs) are natural or synthetic steroids with significant properties that promote plant growth and development. In the current world scenario, research and solutions that can improve plant tolerance to climate change are strategic to ensure food security. The distinctiveness and novelty of this review lie in its comprehensive and detailed approach to the role of BRs in plants under biotic and abiotic stresses. We consolidate information on the action mechanisms on specific organs, providing detailed experimental conclusions of these plant growth regulators, including also commercial products and concentrations tested aiming to mitigate the adverse effects of the stresses. This practical approach highlights the potential of BRs in agriculture and plant protection against stresses. Additionally, our review presents results with plant models and essential food crops, focusing on multidisciplinary approaches and using physiological, biochemical, nutritional, anatomical and agronomic tools to explain the mechanisms of action of brassinosteroids in plants exposed to abiotic and biotic stresses.

Cardiac glycosides inhibit early and late vaccinia virus protein expression.

Cardiac glycosides (CGs) are natural steroid glycosides, which act as inhibitors of the cellular sodium-potassium ATPase pump. Although traditionally considered toxic to human cells, CGs are widely used as drugs for the treatment of cardiovascular-related medical conditions. More recently, CGs have been explored as potential anti-viral drugs and inhibit replication of a range of RNA and DNA viruses. Previously, a compound screen identified CGs that inhibited vaccinia virus (VACV) infection. However, no further investigation of the inhibitory potential of these compounds was performed, nor was there investigation of the stage(s) of the poxvirus lifecycle they impacted. Here, we investigated the anti-poxvirus activity of a broad panel of CGs. We found that all CGs tested were potent inhibitors of VACV replication. Our virological experiments showed that CGs did not impact virus infectivity, binding, or entry. Rather, experiments using recombinant viruses expressing reporter proteins controlled by VACV promoters and arabinoside release assays demonstrated that CGs inhibited early and late VACV protein expression at different concentrations. Lack of virus assembly in the presence of CGs was confirmed using electron microscopy. Thus, we expand our understanding of compounds with anti-poxvirus activity and highlight a yet unrecognized mechanism by which poxvirus replication can be inhibited.

Synthesis of Bufadienolide Cinobufagin via Late-Stage Singlet Oxygen Oxidation/Rearrangement Approach.

This manuscript describes a concise synthesis of cinobufagin, a natural steroid of the bufadienolide family, from readily available dehydroepiandrosterone (DHEA), as well as its α5-epimer derived from 3-epi-andosterone. This synthesis features expedient installation of the 17β-pyrone moiety with the 14β,15β-epoxide and the 16β-acetoxy group using a photochemical regioselective singlet oxygen [4 + 2] cycloaddition followed by CoTPP-promoted in situ endoperoxide rearrangement to provide a 14β,16β-bis-epoxide in 64% yield with a 1.6:1 d.r. This β,β-bis-epoxide intermediate was subsequently subjected to a regioselective scandium(III) trifluoromethanesulfonate catalyzed House-Meinwald rearrangement to establish the 17β-configuration. The synthesis of cinobufagin is achieved in 12 steps (LLS) and 7.6% overall yield, and we demonstrate that it could be used as a platform for the subsequent medicinal chemistry exploration of cinobufagin analogs such as cinobufagin 5α-epimer.

Dioscin alleviates aplastic anemia through regulatory T cells promotion

ABSTRACT Objectives: Aplastic anemia (AA) is one of the immune-mediated bone marrow failure disorders caused by multiple factors, including the inability of CD4 + CD25 + regulatory T cells (Tregs) to negatively regulate cytotoxic T lymphocytes (CTLs). Dioscin is a natural steroid saponin that has a similar structure to steroid hormones. The purpose of this study is to look into the effect of Dioscin on the functions of CD4 + CD25+ Tregs in the AA mouse model and explore its underlying mechanism. Methods: To begin with, bone marrow failure was induced through total body irradiation and allogeneic lymphocyte infusion using male Balb/c mice. After 14 consecutive days of Dioscin orally administrated, the AA mouse model was tested for complete blood counts, HE Staining of the femur, Foxp3, IL-10 and TGF-β. Then CD4 + CD25+ Tregs were isolated from splenic lymphocytes of the AA mouse model, Tregs and the biomarkers and cytokines of Tregs were measured after 24 h of Dioscin intervention treatment in vitro. Results: Dioscin promotes the expression of Foxp3, IL-10, IL-35 and TGF-β, indicating its Tregs-promoting properties. Mechanistically, the administration of Dioscin resulted in the alteration of CD152, CD357, Perforin and CD73 on the surface of Tregs, and restored the expression of Foxp3. Conclusion: Dioscin markedly attenuated bone marrow failure, and promoted Tregs differentiation, suggesting the maintenance of theimmune balance effect of Dioscin. Dioscin attenuates pancytopenia and bone marrow failure via its Tregs promotion properties.

Polyphyllin Ⅲ regulates EMT of lung cancer cells through GSK-3β/β-catenin pathway.

Some studies have found that the application of traditional Chinese medicine in the treatment of lung cancer has achieved satisfying results. Polyphyllin Ⅲ (PP Ⅲ) is a natural steroid saponin from P. polyphylla var. yunnanensis, and its analogs have played a wide role in anticancer research. This study aimed to investigate the effect of PP Ⅲ on the development of lung cancer and its molecular mechanism. A549 and NCI-H1299 cell lines were treated with PP Ⅲ in gradient concentration to detect the IC50 of the cells, and the optimal concentration was selected for subsequent experiments. The effects of PP III treatment on lung cancer were investigated in vitro and in vivo. In vitro experiments, it was found that the proliferation, invasion, migration, and colony formation ability of cancer cells were significantly reduced after PP III treatment, while accompanied by a large number of cell apoptosis. Further detection showed that N-cadherin was significantly decreased, E-cadherin was increased, and Snail and Twist were decreased in A549 cells and NCI-H1299 cells, respectively. In addition, GSK-3β expression was increased, while β-catenin expression was reduced with PP III treatment. In the mouse model, it was demonstrated that the volume of transplanted tumors was significantly reduced after PP Ⅲ treatment. PP Ⅲ has the capacity to inhibit the progression of lung cancer and regulate epithelial-mesenchymal transition through the GSK-3β/β-catenin pathway to suppress the malignant behavior of cancer cells. The application of PP Ⅲ is expected to be an effective method for the treatment of lung cancer.