Sterol regulation of metabolism, homeostasis, and development

Additional mechanism for selective absorption of cholesterol and phytosterols

Phytosterols are structurally similar to cholesterol but they are much less absorbed (<2%) than cholesterol (>50%) in the intestine. We hypothesize that phytosterols are poor substrates of intestinal acyl-CoA: cholesterol acyltransferase 2 (ACAT2), and thus minimal phytosterol esters are formed and packed into chylomicrons, leading to their low absorption. Two isotope tracing models, including a radioactive hamster microsomal ACAT2 reaction model and a differentiated Caco-2 cell model, were established to examine the specificity of ACAT2 to various sterols, including cholesterol, sitosterol, stigmasterol, and campesterol. Both models consistently demonstrated that only cholesterol but not phytosterols could be efficiently esterified by ACAT2 in a time- and dose-dependent manner. Molecular docking further suggested that unfavorable interactions existed between ACAT2 and phytosterols. In conclusion, phytosterols are poor substrates of ACAT2 and thus minimally absorbed. This work provides a theoretical basis for the use of phytosterol-based supplements in treating dyslipidemia and preventing heart diseases.

Cannabidiol exposure during embryonic period caused serious malformation in embryos and inhibited the development of reproductive system in adult zebrafish

Cannabidiol (CBD) is a non-psychoactive component of cannabis with potential applications in biomedicine, food, and cosmetics due to its analgesic, anti-inflammatory, and anticonvulsant properties. However, increasing reports of adverse CBD exposure events underscore the necessity of evaluating its toxicity. In this study, we investigated the developmental toxicity of CBD in zebrafish during the embryonic (0-4 dpf, days post fertilization) and early larval stages (5-7 dpf). The median lethal concentration of CBD in embryos/larvae is 793.28 μg/L. CBD exhibited concentration-dependent manner (ranging from 250 to 1500 μg/L) in inducing serious malformed somatotypes, like shorter body length, pericardial cysts, vitelline cysts, spinal curvature, and smaller eyes. However, no singular deformity predominates. The 5-month-old zebrafish treated with 100 and 200 μg/L of CBD during the embryonic and early larval stages produced fewer offspring with higher natural mortality and malformation rate. Gonadal growth and gamete development were inhibited. Transcriptomic and metabolomic analyses conducted with 400 μg/L CBD on embryos/larvae from 0 to 5 dpf suggested that CBD promoted the formation and transportation of extracellular matrix components on 1 dpf, promoting abnormal cell division and migration, probably resulting in random malformed somatotypes. It inhibited optical vesicle development and photoreceptors formation on 2 and 3 dpf, resulting in damaged sight and smaller eye size. CBD also induced an integrated stress response on 4 and 5 dpf, disrupting redox, protein, and cholesterol homeostasis, contributing to cellular damage, physiological dysfunction, embryonic death, and inhibited reproductive system and ability in adult zebrafish. At the tested concentrations, CBD exhibited developmental toxicity, lethal toxicity, and reproductive inhibition in zebrafish. These findings demonstrate that CBD threatens the model aquatic animal, highlighting the need for additional toxicological evaluations of CBD before its inclusion in dietary supplements, edible food, and other products.

Unveiling the Longevity Potential of Natural Phytochemicals: A Comprehensive Review of Active Ingredients in Dietary Plants and Herbs

Ancient humans used dietary plants and herbs to treat disease and to pursue eternal life. Today, phytochemicals in dietary plants and herbs have been shown to be the active ingredients, some of which have antiaging and longevity-promoting effects. Here, we summarize 210 antiaging phytochemicals in dietary plants and herbs, systematically classify them into 8 groups. We found that all groups of phytochemicals can be categorized into six areas that regulate organism longevity: ROS levels, nutrient sensing network, mitochondria, autophagy, gut microbiota, and lipid metabolism. We review the role of these processes in aging and the molecular mechanism of the health benefits through phytochemical-mediated regulation. Among these, how phytochemicals promote longevity through the gut microbiota and lipid metabolism is rarely highlighted in the field. Our understanding of the mechanisms of phytochemicals based on the above six aspects may provide a theoretical basis for the further development of antiaging drugs and new insights into the promotion of human longevity.

Plasma Lipidomics Reveals Lipid Signatures of Early Pregnancy in Mares

Understanding the systemic biochemistry of early pregnancy in the mare is essential for developing new diagnostics and identifying causes for pregnancy loss. This study aimed to elucidate the dynamic lipidomic changes occurring during the initial stages of equine pregnancy, with a specific focus on days 7 and 14 post-ovulation. By analysing and comparing the plasma lipid profiles of pregnant and non-pregnant mares, the objective of this study was to identify potential biomarkers for pregnancy and gain insights into the biochemical adaptations essential for supporting maternal recognition of pregnancy and early embryonic development. Employing discovery lipidomics, we analysed plasma samples from pregnant and non-pregnant mares on days 7 and 14 post-conception using the SCIEX ZenoTOF 7600 system. This high-resolution mass spectrometry approach enabled us to comprehensively profile and compare the lipidomes across these critical early gestational timepoints. Our analysis revealed significant lipidomic alterations between pregnant and non-pregnant mares and between days 7 and 14 of pregnancy. Key findings include the upregulation of bile acids, sphingomyelins, phosphatidylinositols, and triglycerides in pregnant mares. These changes suggest enhanced lipid synthesis and mobilization, likely associated with the embryo's nutritional requirements and the establishment of embryo-maternal interactions. There were significant differences in lipid metabolism between pregnant and non-pregnant mares, with a notable increase in the sterol lipid BA 24:1;O5 in pregnant mares as early as day 7 of gestation, suggesting it as a sensitive biomarker for early pregnancy detection. Notably, the transition from day 7 to day 14 in pregnant mares is characterized by a shift towards lipids indicative of membrane biosynthesis, signalling activity, and preparation for implantation. The study demonstrates the profound lipidomic shifts that occur in early equine pregnancy, highlighting the critical role of lipid metabolism in supporting embryonic development. These findings provide valuable insights into the metabolic adaptations during these period and potential biomarkers for early pregnancy detection in mares.

Genome-wide scan of Flortaucipir PET levels finds JARID2 associated with cerebral tau deposition

BACKGROUND

Genetic research on Alzheimer's disease (AD) has primarily focused on amyloid-β (Aβ) pathogenesis, with fewer studies exploring tau pathology. Elucidating the genetic basis of tau pathology could identify novel pathways in AD.

METHODS

We conducted a genome-wide association study of tau standard uptake value ratios (SUVRs) from [18]F-flortaucipir positron emission tomography (PET) images to identify genetic variants underlying Tau pathology. Genetic data and tau-SUVRs from [18]F-flortaucipir PET images were acquired from the A4 (311 with preclinical AD) and ADNI (280 cognitively normal, 76 with mild cognitive impairment, and 19 AD patients) studies. Circulating plasma proteins in UK Biobank Pharma Proteomics Project (UKBPPP, N=54,129) were used to validate genetic findings. SNP genotypes were tested for association with Tau-SUVR levels adjusting for age, sex and population substructure variables. AD association of polygenic risk scores (PRS) of tau and amyloid-SUVRs were assessed. Causal effect of plasma protein levels on Tau pathology were tested using Mendelian randomization analyses.

RESULTS

GWAS of tau-SUVR revealed two significant loci: rs78636169 (P=5.76×10-10) in JARID2 and rs7292124 (P=2.20×10-8) near ISX. Gene-based analysis of tau deposition highlighted APOE (P=2.55×10-6), CTNNA3 (P=2.86×10-6) and JARID2 (P=1.23×10-4), a component of the PRC2 multi-protein complex which regulates gene expression. Mendelian randomization analysis of available circulating plasma proteins in the UK Biobank Pharma Proteomics Project (UKBPPP) identified LRRFIP1, a protein that binds with PRC2 multi-protein complex, as potentially causally linked to tau pathology. Genes associated with both amyloid and tau pathologies were enriched in endocytosis and signal transduction pathways. AD polygenic risk score (PRS) was associated with amyloid-SUVR but not with tau-SUVR. Amyloid-SUVR PRS had a notable association with AD clinical status, particularly in younger APOE-ε4 carriers, whereas tau-SUVR PRS showed a stronger association in older carriers.

CONCLUSION

We identified a novel potential therapeutic target, JARID2 in the PRC2 multi-protein complex, for tau pathology. Furthermore, gene pathway analysis clarified the distinct roles of Aβ and tau in AD progression, underscoring the complexity of genetic influences across different stages of the disease.

tRNA-m1A methylation controls the infection of Magnaporthe oryzae by supporting ergosterol biosynthesis

Ergosterols are essential components of fungal plasma membranes. Inhibitors targeting ergosterol biosynthesis (ERG) genes are critical for controlling fungal pathogens, including Magnaporthe oryzae, the fungus that causes rice blast. However, the translational mechanisms governing ERG gene expression remain largely unexplored. Here, we show that the Trm6/Trm61 complex catalyzes dynamic N1-methyladenosine at position 58 (m1A58) in 51 transfer RNAs (tRNAs) of M. oryzae, significantly influencing translation at both the initiation and elongation stages. Notably, tRNA m1A58 promotes elongation speed at most cognate codons mainly by enhancing eEF1-tRNA binding rather than affecting tRNA abundance or charging. The absence of m1A58 leads to substantial decreases in the translation of ERG genes, ergosterol production, and, consequently, fungal virulence. Simultaneously targeting the Trm6/Trm61 complex and the ergosterol biosynthesis pathway markedly improves rice blast control. Our findings demonstrate an important role of m1A58-mediated translational regulation in ergosterol production and fungal infection, offering a potential strategy for fungicide development.

Lupeol improves bile acid metabolism and metabolic dysfunction-associated steatotic liver disease in mice via FXR signaling pathway and gut-liver axis

Metabolic dysfunction-associated steatotic liver disease (MASLD) has a multifactorial and complex pathogenesis. Notably, the disorder of Bile acid (BA) metabolism and lipid metabolism-induced lipotoxicity are the main risk factors of MASLD. Lupeol, traditional regional medicine from Xinjiang, has a long history of use for its anti-inflammatory, anti-tumor, and immune-modulating properties. Recent research suggests its potential as a therapeutic option for MASLD due to its proposed binding capacity to the nuclear BA receptor, Farnesoid X receptor (FXR), hence could represent a therapeutic option for MASLD. In this study, a natural triterpenoid drug lupeol improved BA metabolism and MASLD in mice through the FXR signaling pathway and the gut-liver axis. Furthermore, lupeol effectively restored gut healthiness and improved intestinal immunity, barrier integrity, and inflammation, as indicated by the reconstructed gut flora. Compared with fenofibrate (Feno), lupeol treatment significantly reduced weight gain, fat deposition, and liver injury, decreased serum total cholesterol (TC) and triglyceride (TG) levels, and alleviated hepatic steatosis and liver inflammation. BA analysis showed that lupeol treatment accelerated BA efflux and decreased uptake of BA by increasing hepatic FXR and bile salt export pump (BSEP) expression. Gut microbiota alterations could be related to enhanced fecal BA excretion in lupeol-treated mice. Therefore, consumption of lupeol may prevent HFD-induced MASLD and BA accumulation, possibly via the FXR signaling pathway and regulating the gut microbiota.

Crucial Involvement of Heme Biosynthesis in Vegetative Growth, Development, Stress Response, and Fungicide Sensitivity of Fusarium graminearum

Heme biosynthesis is a highly conserved pathway from bacteria to higher animals. Heme, which serves as a prosthetic group for various enzymes involved in multiple biochemical processes, is essential in almost all species, making heme homeostasis vital for life. However, studies on the biological functions of heme in filamentous fungi are scarce. In this study, we investigated the role of heme in Fusarium graminearum. A mutant lacking the rate-limiting enzymes in heme synthesis, coproporphyrinogen III oxidase (Cpo) or ferrochelatase (Fc), was constructed using a homologous recombination strategy. The results showed that the absence of these enzymes was lethal to F. graminearum, but the growth defect could be rescued by the addition of hemin, so we carried out further studies with the help of hemin. The results demonstrated that heme was required for the activity of FgCyp51, and its absence increased the sensitivity to tebuconazole and led to the upregulation of FgCYP51 in F. graminearum. Additionally, heme plays an indispensable role in the life cycle of F. graminearum, which is essential for vegetative growth, conidiation, external stress response (especially oxidative stress), lipid accumulation, fatty acid β-oxidation, autophagy, and virulence.

FgFAD12 Regulates Vegetative Growth, Pathogenicity and Linoleic Acid Biosynthesis in Fusarium graminearum

Polyunsaturated fatty acids (PUFAs), as important components of lipids, play indispensable roles in the development of all organisms. ∆12 fatty acid desaturase (FAD12) is a speed-determining step in the biosynthesis of PUFAs. Here, we report the characterization of FAD12 in Fusarium graminearum, which is the prevalent agent of Fusarium head blight, a destructive plant disease worldwide. The results demonstrated that deletion of the FgFAD12 gene resulted in defects in vegetative growth, conidial germination and plant pathogenesis but not sexual reproduction. A fatty acid analysis further proved that the deletion of FgFAD12 restrained the reaction of oleic acid to linoleic acid, and a large amount of oleic acid was detected in the cells. Moreover, the ∆Fgfad12 mutant showed increased resistance to osmotic stress and reduced tolerance to oxidative stress. The expression of FgFAD12 did show a temperature-dependent manner, which was not affected at a low temperature of 10 °C when compared to 25 °C. RNA-seq analysis further demonstrated that most genes enriched in fatty acid metabolism, the biosynthesis of unsaturated fatty acids, fatty acid biosynthesis, fatty acid degradation, steroid biosynthesis and fatty acid elongation pathways were significantly up-regulated in the ∆Fgfad12 mutants. Overall, our results indicate that FgFAD12 is essential for linoleic acid biosynthesis and plays an important role in the infection process of F. graminearum.

The natural polycyclic tetramate macrolactam HSAF inhibit Fusarium graminearum through altering cell membrane integrity by targeting FgORP1

Fusarium graminearum is a dominant phytopathogenic fungus causing Fusarium head blight (FHB) in cereal crops. Heat-stable antifungal factor (HSAF) is a polycyclic tetramate macrolactam (PoTeM) isolated from Lysobacter enzymogenes that exhibits strong antifungal activity against F. graminearum. HSAF significantly reduces the DON production and virulence of F. graminearum. Importantly, HSAF exhibited no cross-resistance to carbendazim, phenamacril, tebuconazole and pydiflumetofen. However, the target protein of HSAF in F. graminearum is unclear. In this study, the oxysterol-binding protein FgORP1 was identified as the potential target of HSAF using surface plasmon resonance (SPR) combined with RNA-sequence (RNA-seq). The RNA-seq results showed cell membrane and ergosterol biosynthesis were significantly impacted by HSAF in F. graminearum. Molecular docking showed that HSAF binds with arginine 1205 and glutamic acid 1212, which are located in the oxysterol-binding domain of FgORP1. The two amino acids in FgORP1 are responsible for HSAF resistance in F. graminearum though site-directed mutagenesis. Furthermore, deletion of FgORP1 led to significantly decreased sensitivity to HSAF. Additionally, FgORP1 regulates the mycelial growth, conidiation, DON production, ergosterol biosynthesis and virulence in F. graminearum. Overall, our findings revealed the mode of action of HSAF against F. graminearum, indicating that HSAF is a promising fungicide for controlling FHB.

Physiological trade-off of marine fish under Zn deficient and excess conditions

Fish can regulate their Zn body bioaccumulation, but the mechanisms and physiological responses at the organ level are still largely unknown. In the present study, we exposed the marine seabreams under different Zn levels (deficient, optimum and excess levels) over a period of 4 weeks and examined how fish maintained its regulation of bioaccumulation with associated physiological effects at the fish intestinal organ. Our results indicated that fish intestinal organs constantly controlled the Zip family to "rob" more Zn under Zn-deficiency (with a dietary level of 7.9 mg/kg), whereas restricted the Zn efflux to preserve the intestinal function. Under Zn-excess conditions (193.3 mg/kg), the fish intestine maintained a limited Zn homeostasis (37.8-44.6 μg/mg) by initially inhibiting the influx through the Zip family receptor, but later accelerating both influx and efflux of Zn. Based on the WGCNA method, Zn deficient dietary exposure first resulted in defense response with subsequent switching to antioxidant defense. Instead, excess Zn first triggered the immunological response, but then led to physiological toxicity (abnormal in lipid metabolism). Although Zn had multiple biological functions, it was preferentially involved in lipid metabolism under different dietary Zn doses. This study provided direct evidence for Zn regulation at the organ level and detoxification mechanisms against potential environmental toxicity in fish.

Review of Eukaryote Cellular Membrane Lipid Composition, with Special Attention to the Fatty Acids

Biological membranes, primarily composed of lipids, envelop each living cell. The intricate composition and organization of membrane lipids, including the variety of fatty acids they encompass, serve a dynamic role in sustaining cellular structural integrity and functionality. Typically, modifications in lipid composition coincide with consequential alterations in universally significant signaling pathways. Exploring the various fatty acids, which serve as the foundational building blocks of membrane lipids, provides crucial insights into the underlying mechanisms governing a myriad of cellular processes, such as membrane fluidity, protein trafficking, signal transduction, intercellular communication, and the etiology of certain metabolic disorders. Furthermore, comprehending how alterations in the lipid composition, especially concerning the fatty acid profile, either contribute to or prevent the onset of pathological conditions stands as a compelling area of research. Hence, this review aims to meticulously introduce the intricacies of membrane lipids and their constituent fatty acids in a healthy organism, thereby illuminating their remarkable diversity and profound influence on cellular function. Furthermore, this review aspires to highlight some potential therapeutic targets for various pathological conditions that may be ameliorated through dietary fatty acid supplements. The initial section of this review expounds on the eukaryotic biomembranes and their complex lipids. Subsequent sections provide insights into the synthesis, membrane incorporation, and distribution of fatty acids across various fractions of membrane lipids. The last section highlights the functional significance of membrane-associated fatty acids and their innate capacity to shape the various cellular physiological responses.

Lipid metabolism reprogramming in head and neck cancer

Lipid metabolism reprogramming is one of the most prominent metabolic anomalies in cancer, wherein cancer cells undergo dysregulation of lipid metabolism to acquire adequate energy, cell membrane building blocks, as well as signaling molecules essential for cell proliferation, survival, invasion, and metastasis. These adaptations enable cancer cells to effectively respond to challenges posed by the tumor microenvironment, leading to cancer therapy resistance and poor cancer prognosis. Head and neck cancer, ranking as the seventh most prevalent cancer, exhibits numerous abnormalities in lipid metabolism. Nevertheless, the precise role of lipid metabolic rewiring in head and neck cancer remains unclear. In line with the LIPID MAPS Lipid Classification System and cancer risk factors, the present review delves into the dysregulated molecules and pathways participating in the process of lipid uptake, biosynthesis, transportation, and catabolism. We also present an overview of the latest advancements in understanding alterations in lipid metabolism and how they intersect with the carcinogenesis, development, treatment, and prognosis of head and neck cancer. By shedding light on the significance of metabolic therapy, we aspire to improve the overall prognosis and treatment outcomes of head and neck cancer patients.

Profiling lipidomic changes in dengue-resistant and dengue-susceptible strains of Colombian Aedes aegypti after dengue virus challenge

The mosquito Aedes aegypti is the primary vector for all four serotypes of dengue viruses (DENV1-4), which infect millions across the globe each year. Traditional insecticide programs have been transiently effective at minimizing cases; however, insecticide resistance and habitat expansion have caused cases of DENV to surge over the last decade. There is an urgent need to develop novel vector control measures, but these are contingent on a detailed understanding of host-parasite interactions. Here, we have utilized lipidomics to survey the profiles of naturally DENV-resistant (Cali-MIB) or susceptible (Cali-S) populations of Ae. aegypti, isolated from Cali, Colombia, when fed on blood meals containing DENV. Control insects were fed on a DENV-free blood meal. Midguts were dissected from Cali-MIB and Cali-S females at three time points post-infectious blood meal, 18, 24 and 36h, to identify changes in the lipidome at key times associated with the entry, replication and exit of DENV from midgut cells. We used principal component analysis to visualize broad patterns in lipidomic profiles between the treatment groups, and significance analysis of microarray to determine lipids that were altered in response to viral challenge. These data can be used to identify molecules or metabolic pathways particular to the susceptible or refractory phenotypes, and possibly lead to the generation of stable, DENV-resistant strains of Ae. aegypti.

Molecular characterization and transcriptional regulation analysis of the Torreya grandis squalene synthase gene involved in sitosterol biosynthesis and drought response

The kernel of Torreya grandis cv. 'Merrillii' (Cephalotaxaceae) is a rare nut with a variety of bioactive compounds and a high economic value. β-sitosterol is not only the most abundant plant sterol but also has various biological effects, such as antimicrobial, anticancer, anti-inflammatory, lipid-lowering, antioxidant, and antidiabetic activities. In this study, a squalene synthase gene from T. grandis, TgSQS, was identified and functionally characterized. TgSQS encodes a deduced protein of 410 amino acids. Prokaryotic expression of the TgSQS protein could catalyze farnesyl diphosphate to produce squalene. Transgenic Arabidopsis plants overexpressing TgSQS showed a significant increase in the content of both squalene and β-sitosterol; moreover, their drought tolerance was also stronger than that of the wild type. Transcriptome data from T. grandis seedlings showed that the expression levels of sterol biosynthesis pathway-related genes, such as HMGS, HMGR, MK, DXS, IPPI, FPPS, SQS, and DWF1, increased significantly after drought treatment. We also demonstrated that TgWRKY3 directly bound to the TgSQS promoter region and regulated its expression through a yeast one-hybrid experiment and a dual luciferase experiment. Together, these findings demonstrate that TgSQS has a positive role in β-sitosterol biosynthesis and in protecting against drought stress, emphasizing its importance as a metabolic engineering tool for the simultaneous improvement of β-sitosterol biosynthesis and drought tolerance.

Structure Elucidation and Biosynthesis of Nannosterols A and B, Myxobacterial Sterols from Nannocystis sp. MNa10993

Myxobacteria represent an underinvestigated source of chemically diverse and biologically active secondary metabolites. Here, we report the discovery, isolation, structure elucidation, and biological evaluation of two new bacterial sterols, termed nannosterols A and B (1, 2), from the terrestrial myxobacterium Nannocystis sp. (MNa10993). Nannosterols feature a cholestanol core with numerous modifications including a secondary alcohol at position C-15, a terminal vicinal diol side chain at C-24-C-25 (1, 2), and a hydroxy group at the angular methyl group at C-18 (2), which is unprecedented for bacterial sterols. Another rare chemical feature of bacterial triterpenoids is a ketone group at position C-7, which is also displayed by 1 and 2. The combined exploration based on myxobacterial high-resolution secondary metabolome data and genomic in silico investigations exposed the nannosterols as frequently produced sterols within the myxobacterial suborder of Nannocystineae. The discovery of the nannosterols provides insights into the biosynthesis of these new myxobacterial sterols, with implications in understanding the evolution of sterol production by prokaryotes.

The sphinganine C4-hydroxylase FgSur2 regulates sensitivity to azole antifungal agents and virulence of Fusarium graminearum

Lipid rafts consisting of ergosterol and sphingolipids in the lipid membrane of cells play important roles in various cellular processes. However, the functions of sphingolipids and their synthetic genes in phytopathogenic fungi have not been well understood yet. In this study, we conducted genome-wide searches and carried out systematic gene deletion analysis of the sphingolipid synthesis pathway in Fusarium graminearum, a causal agent of Fusarium head blight of wheat and other cereal crops worldwide. Mycelial growth assays showed that deletion of FgBAR1, FgLAC1, FgSUR2 or FgSCS7 resulted in markedly reduced hyphal growth. Fungicide sensitivity tests showed that the sphinganine C4-hydroxylase gene FgSUR2 deletion mutant (ΔFgSUR2) exhibited significantly increased susceptibility to azole fungicides. In addition, this mutant displayed a remarkable increase in cell membrane permeability. Importantly, ΔFgSUR2 was defective in deoxynivalenol (DON) toxisome formation, leading to dramatically decreased DON biosynthesis. Moreover, the deletion of FgSUR2 resulted in dramatically decreased virulence of the pathogen on host plants. Taken together, these results indicate that FgSUR2 plays an important role in regulating the susceptibility to azoles and virulence of F. graminearum.

Olive juice dry extract containing hydroxytyrosol, as a nontoxic and safe substance: Results from pre-clinical studies and review of toxicological studies

Products derived from olives, such as the raw fruit and oils, are widely consumed due to their taste, and purported nutritional/health benefits. Phenolic compounds, especially hydroxytyrosol (HT), have been proposed as one of the key substances involved in these effects. An olive juice extract, standardized to contain 20% HT ("OE20HT"), was produced to investigate its health benefits. The aim of this study was to demonstrate the genotoxic safety of this ingredient based on in vitro Ames assay and in vitro micronucleus assay. Results indicated that OE20HT was not mutagenic at concentrations of up to 5000 µg/plate, with or without metabolic activation, and was neither aneugenic nor clastogenic after 3-hour exposure at concentrations of up to 60 µg/mL with or without metabolic activation, or after 24-hour exposure at concentrations of up to 40 µg/mL. To further substantiate the safety of OE20HT following ingestion without conducting additional animal studies, a comprehensive literature review was conducted. No safety concerns were identified based on acute or sub-chronic studies in animals, including reproductive and developmental studies. These results were supported by clinical studies demonstrating the absence of adverse effects after oral supplementation with olive extracts or HT. Based on in vitro data and the literature review, the OE20HT extract is therefore considered as safe for human consumption at doses up to 2.5 mg/kg body weight/day.

Steroid hormone signaling: What we can learn from insect models

Ecdysteroids are a group of steroid hormones in arthropods with pleiotropic functions throughout their life history. Ecdysteroid research in insects has made a significant contribution to our current understanding of steroid hormone signaling in metazoans, but how far can we extrapolate our findings in insects to other systems, such as mammals? In this chapter, we compare steroid hormone signaling in insects and mammals from multiple perspectives and discuss similarities and differences between the two lineages. We also highlight a few understudied areas and remaining questions of steroid hormone biology in metazoans and propose potential future research directions.

Cannabinoids activate the insulin pathway to modulate mobilization of cholesterol in C. elegans

The nematode Caenorhabditis elegans requires exogenous cholesterol to survive and its depletion leads to early developmental arrest. Thus, tight regulation of cholesterol storage and distribution within the organism is critical. Previously, we demonstrated that the endocannabinoid (eCB) 2-arachidonoylglycerol (2-AG) plays a key role in C. elegans since it modulates sterol mobilization. However, the mechanism remains unknown. Here we show that mutations in the ocr-2 and osm-9 genes, coding for transient receptors potential V (TRPV) ion channels, dramatically reduce the effect of 2-AG in cholesterol mobilization. Through genetic analysis in combination with the rescue of larval arrest induced by sterol starvation, we found that the insulin/IGF-1signaling (IIS) pathway and UNC-31/CAPS, a calcium-activated regulator of neural dense-core vesicles release, are essential for 2-AG-mediated stimulation of cholesterol mobilization. These findings indicate that 2-AG-dependent cholesterol trafficking requires the release of insulin peptides and signaling through the DAF-2 insulin receptor. These results suggest that 2-AG acts as an endogenous modulator of TRPV signal transduction to control intracellular sterol trafficking through modulation of the IGF-1 signaling pathway

In silico Prediction and Pharmacokinetic Studies on Glucosinolates as a Potential Drug and Key Inhibitor Molecule for Lanosterol-14α- demethylase: A Fungal Membrane Biosynthesis Enzyme

BACKGROUND

Glucosinolates (β-thioglucoside-N-hydroxysulfates) are a water-soluble organic anion with sulfur- and nitrogen-containing glycosides which are found in abundance in Cruciferous plants. Ergosterol (ERG13) lanosterol-14α-demethylase protein has been targeted for inhibition studies as a key regulator enzyme of fungal membrane biosynthesis.

OBJECTIVES

To understand the molecular mechanism of inhibition of Ergosterol (ERG13) lanosterol- 14α-demethylase by various phytochemicals from brassicales, i.e., glucosinolates and their potential role as putative drug molecules.

METHODS

In this study, in silico analyses were performed to predict the molecular basis of various glucosinolates as a potential inhibitor of lanosterol-14α-demethylase protein, which is a key regulator of fungal membrane biosynthesis and its pharmacodynamics and toxicity profile. 3d structures of various glucosinolates were retrieved from PubChem, and the target protein, lanosterol-14α-demethylase (Pdb ID- 4lxj), was retrieved from the RCSB protein data bank. Molecular docking and interactions were carried out using the PyRx software using the AutoDOCK toolbar with default parameters. Dru- LiTo, ORISIS web servers were used to predict various drug likeliness predictions and Lipinski's Rule of 5, whereas admetSAR was used for prediction of toxicity, and PASS Program was used to study the antifungal and antimicrobial properties of these compounds.

RESULTS

This study shows that among the different compounds screened, gluconasturtiin, Glucotropaeolin, and Indolylmethyl-Glucosinolate showed the highest binding energies of -8.7 kcal/mol, -8.5 kcal/mol, and -8.3 kcal/mol with the lanosterol-14α-demethylase, respectively. Further all the compounds follow the Lipinski's rule as well as they are found to be non-carcinogenic and non-cytotoxic in nature. These compounds also show antifungal properties.

CONCLUSION

This study thus reveals that various glucosinolates interact with the ERG13 enzyme at various amino acid positions, which behaves as a catalytic site, thus indicates the probable mechanism of inactivation, and subsequently, these can be used as potential drug molecules. In vitro studies can be taken to further examine the utility of these compounds as antifungal agents.

Effects of impaired steryl ester biosynthesis on tomato growth and developmental processes

Steryl esters (SE) are stored in cytoplasmic lipid droplets and serve as a reservoir of sterols that helps to maintain free sterols (FS) homeostasis in cell membranes throughout plant growth and development, and provides the FS needed to meet the high demand of these key plasma membrane components during rapid plant organ growth and expansion. SE are also involved in the recycling of sterols and fatty acids released from membranes during plant tissues senescence. SE are synthesized by sterol acyltransferases, which catalyze the transfer of long-chain fatty acid groups to the hydroxyl group at C3 position of FS. Depending on the donor substrate, these enzymes are called acyl-CoA:sterol acyltransferases (ASAT), when the substrate is a long-chain acyl-CoA, and phospholipid:sterol acyltransferases (PSAT), which use a phospholipid as a donor substrate. We have recently identified and preliminary characterized the tomato (Solanum lycopersicum cv. Micro-Tom) SlASAT1 and SlPSAT1 enzymes. To gain further insight into the biological role of these enzymes and SE biosynthesis in tomato, we generated and characterized CRISPR/Cas9 single knock-out mutants lacking SlPSAT1 (slpsat1) and SlASAT1 (slasat1), as well as the double mutant slpsat1 x slasat1. Analysis of FS and SE profiles in seeds and leaves of the single and double mutants revealed a strong depletion of SE in slpsat1, that was even more pronounced in the slpsat1 x slasat1 mutant, while an increase of SE levels was observed in slasat1. Moreover, SlPSAT1 and SlASAT1 inactivation affected in different ways several important cellular and physiological processes, like leaf lipid bo1dies formation, seed germination speed, leaf senescence, and the plant size. Altogether, our results indicate that SlPSAT1 has a predominant role in tomato SE biosynthesis while SlASAT1 would mainly regulate the flux of the sterol pathway. It is also worth to mention that some of the metabolic and physiological responses in the tomato mutants lacking functional SlPSAT1 or SlASAT1 are different from those previously reported in Arabidopsis, being remarkable the synergistic effect of SlASAT1 inactivation in the absence of a functional SlPSAT1 on the early germination and premature senescence phenotypes.

Rational development of mycobacteria cell factory for advancing the steroid biomanufacturing

Steroidal resource occupies a vital proportion in the pharmaceutical industry attributing to their important therapeutic effects on fertility, anti-inflammatory and antiviral activities. Currently, microbial transformation from phytosterol has become the dominant strategy of steroidal drug intermediate synthesis that bypasses the traditional chemical route. Mycobacterium sp. serve as the main industrial microbial strains that are capable of introducing selective functional modifications of steroidal intermediate, which has become an indispensable platform for steroid biomanufacturing. By reviewing the progress in past two decades, the present paper concentrates mainly on the microbial rational modification aspects that include metabolic pathway editing, key enzymes engineering, material transport pathway reinforcement, toxic metabolic intermediates removal and byproduct reconciliation. In addition, progress on omics analysis and direct genetic manipulation are summarized and classified that may help reform the industrial hosts with more efficiency. The paper provides an insightful present for steroid biomanufacturing especially on the current trends and prospects of mycobacteria.

Bioactivity of mefentrifluconazole against different Fusarium spp

Emergence and development of resistance to 14α-demethylase inhibitors (DMIs) have become a critical issue in both agriculture and medical fields. Mefentrifluconazole, the first isopropanol triazole fungicide belonging to a new subclass of DMIs, has been proposed to show high activity, minimal adverse side effects, and inconsistent cross resistance with other DMIs due to its high structural flexibility. In this study, mefentrifluconazole showed disparate inhibitory activity against the mycelium growth of seven tested Fusarium species. The most sensitive species included F. oxysporum, F. proliferatum, F. commuae, and F. fujikuroi, followed by F. equiseti and F. graminearum, while F. solani was most insensitive. Consistently, mefentrifluconazole presented the strongest inhibiting effects on conidium germination, cell membrane integrity, and ergosterol biosynthesis in F. fujikuroi, followed by F. graminearum, while F. solani ranked last. Further results indicated that all F. fujikuroi isolates causing rice bakanae disease (RBD) were sensitive to mefentrifluconazole regardless of their resistance to prochloraz, tebuconazole, carbendazim, and phenamacril. Additionally, the inoculation tests found that mefentrifluconazole presented a better protective efficacy on rice seedlings when applied 12 h before the F. fujikuroi inoculation, compared to applied 12 h post the inoculation. Overall, this study demonstrated the various bioactivity of mefentrifluconazole combating Fusarium spp. and put new insights into RBD management as well as the applications of DMIs.

An unprecedented ergostane with a 6/6/5 tricyclic 13(14 → 8)abeo-8,14-seco skeleton from Talaromyces adpressus

Talasterone A (1), an unprecedented 6/6/5 tricyclic 13(14 → 8)abeo-8,14-seco-ergostane steroid, together with two known congeners dankasterone B (2) and (14β,22E)-9,14-dihydroxyergosta-4,7,22-triene-3,6-dione (3), were characterized from Talaromyces adpressus. The structure of 1 with absolute configuration was elucidated based on NMR spectroscopic data and ECD calculation. Compound 2 belongs to a class of unconventional 13(14 → 8)abeo-ergostanes, which have been renewed via the 1,2-migration of C-13-C-14 bond to C-8. In addition, compound 1 represents the first example of ergostane with a tricyclic 13(14 → 8)abeo-8,14-seco-ergostane skeleton. The proposed biosynthetic pathway was established with the support of the coisolation of the known congeners from the producing organism. It is especially noteworthy that compound 1 exhibited potent anti-inflammatory activity with an IC₅₀ value of 8.73 ± 0.66 μM, inhibiting the NF-κB pathway and thus reducing the production of proinflammatory cytokines.

Recent progress in strategies for steroid production in yeasts

As essential structural molecules of fungal cell membrane, ergosterol is not only an important component of fungal growth and stress-resistance but also a key precursor for manufacturing steroid drugs of pharmaceutical or agricultural significance. So far, ergosterol biosynthesis in yeast has been elucidated elaborately, and efforts have been made to increase ergosterol production through regulation of ergosterol metabolism and storage. Furthermore, the same intermediates shared by yeasts and animals or plants make the construction of heterologous sterol pathways in yeast a promising approach to synthesize valuable steroids, such as phytosteroids and animal steroid hormones. During these challenging processes, several obstacles have arisen and been combated with great endeavors. This paper reviews recent research progress of yeast metabolic engineering for improving the production of ergosterol and heterologous steroids. The remaining tactics are also discussed.

Biosynthesis and the Roles of Plant Sterols in Development and Stress Responses

Plant sterols are important components of the cell membrane and lipid rafts, which play a crucial role in various physiological and biochemical processes during development and stress resistance in plants. In recent years, many studies in higher plants have been reported in the biosynthesis pathway of plant sterols, whereas the knowledge about the regulation and accumulation of sterols is not well understood. In this review, we summarize and discuss the recent findings in the field of plant sterols, including their biosynthesis, regulation, functions, as well as the mechanism involved in abiotic stress responses. These studies provide better knowledge on the synthesis and regulation of sterols, and the review also aimed to provide new insights for the global role of sterols, which is liable to benefit future research on the development and abiotic stress tolerance in plant.

Identification of Inhibitors of Cholesterol Transport Proteins Through the Synthesis of a Diverse, Sterol-Inspired Compound Collection

Cholesterol transport proteins regulate a vast array of cellular processes including lipid metabolism, vesicular and non-vesicular trafficking, organelle contact sites, and autophagy. Despite their undoubted importance, the identification of selective modulators of this class of proteins has been challenging due to the structural similarities in the cholesterol-binding site. Herein we report a general strategy for the identification of selective inhibitors of cholesterol transport proteins via the synthesis of a diverse sterol-inspired compound collection. Fusion of a primary sterol fragment to an array of secondary privileged scaffolds led to the identification of potent and selective inhibitors of the cholesterol transport protein Aster-C, which displayed a surprising preference for the unnatural-sterol AB-ring stereochemistry and new inhibitors of Aster-A. We propose that this strategy can and should be applied to any therapeutically relevant sterol-binding protein.

An Immunomodulatory Transcriptional Signature Associated With Persistent Listeria Infection in Hepatocytes

Listeria monocytogenes causes severe foodborne illness in pregnant women and immunocompromised individuals. After the intestinal phase of infection, the liver plays a central role in the clearance of this pathogen through its important functions in immunity. However, recent evidence suggests that during long-term infection of hepatocytes, a subpopulation of Listeria may escape eradication by entering a persistence phase in intracellular vacuoles. Here, we examine whether this long-term infection alters hepatocyte defense pathways, which may be instrumental for bacterial persistence. We first optimized cell models of persistent infection in human hepatocyte cell lines HepG2 and Huh7 and primary mouse hepatocytes (PMH). In these cells, Listeria efficiently entered the persistence phase after three days of infection, while inducing a potent interferon response, of type I in PMH and type III in HepG2, while Huh7 remained unresponsive. RNA-sequencing analysis identified a common signature of long-term Listeria infection characterized by the overexpression of a set of genes involved in antiviral immunity and the under-expression of many acute phase protein (APP) genes, particularly involved in the complement and coagulation systems. Infection also altered the expression of cholesterol metabolism-associated genes in HepG2 and Huh7 cells. The decrease in APP transcripts was correlated with lower protein abundance in the secretome of infected cells, as shown by proteomics, and also occurred in the presence of APP inducers (IL-6 or IL-1β). Collectively, these results reveal that long-term infection with Listeria profoundly deregulates the innate immune functions of hepatocytes, which could generate an environment favorable to the establishment of persistent infection.

Mycolicibacterium cell factory for the production of steroid-based drug intermediates

Steroid-based drugs have been developed as the second largest medical category in pharmaceutics. The well-established route of steroid industry includes two steps: the conversion of natural products with a steroid framework to steroid-based drug intermediates and the synthesis of varied steroid-based drugs from steroid-based drug intermediates. The biosynthesis of steroid-based drug intermediates from phytosterols by Mycolicibacterium cell factories bypasses the potential undersupply of diosgenin in the traditional steroid chemical industry. Moreover, the biosynthesis route shows advantages on multiple steroid-based drug intermediate products, more ecofriendly processes, and consecutive reactions carried out in one operation step and in one pot. Androsta-4-ene-3,17-dione (AD), androsta-1,4-diene-3,17-dione (ADD) and 9-hydroxyandrostra-4-ene-3,17-dione (9-OH-AD) are the representative steroid-based drug intermediates synthesized by mycolicibacteria. Other steroid metabolites of mycolicibacteria, like 4-androstene-17β-ol-3-one (TS), 22-hydroxy-23,24-bisnorchol-4-ene-3-one (4-HBC), 22-hydroxy-23,24-bisnorchol-1,4-diene-3-one (1,4-HBC), 9,22-dihydroxy-23,24-bisnorchol-4-ene-3-one (9-OH-HBC), 3aα-H-4α-(3'-propionic acid)-7aβ-methylhexahydro-1,5-indanedione (HIP) and 3aα-H-4α-(3'-propionic acid)-5α-hydroxy-7aβ-methylhexahydro-1-indanone-δ-lactone (HIL), also show values as steroid-based drug intermediates. To improve the bio-production efficiency of the steroid-based drug intermediates, mycolicibacterial strains and biotransformation processes have been continuously studied in the past decades. Many mycolicibacteria that accumulate steroid drug intermediates have been isolated, and subsequently optimized by conventional mutagenesis and genetic engineering. Especially, with the clarification of the mycolicibacterial steroid metabolic pathway and the developments on gene editing technologies, rational design is becoming an important measure for the construction and optimization of engineered mycolicibacteria strains that produce steroid-based drug intermediates. Hence, by reviewing researches in the past two decades, this article updates the overall process of steroid metabolism in mycolicibacteria and provides comprehensive schemes for the rational construction of mycolicibacterial strains that accumulate steroid-based drug intermediates. In addition, the special strategies for the bioconversion of highly hydrophobic steroid in aqueous media are discussed as well.

Chronic tissue inflammation and metabolic disease

In this review, Lee and Olefsky discuss the characteristics of chronic inflammation in the major metabolic tissues and how obesity triggers these events, including a focus on the role of adipose tissue hypoxia and macrophage-derived exosomes.

Obesity is the most common cause of insulin resistance, and the current obesity epidemic is driving a parallel rise in the incidence of T2DM. It is now widely recognized that chronic, subacute tissue inflammation is a major etiologic component of the pathogenesis of insulin resistance and metabolic dysfunction in obesity. Here, we summarize recent advances in our understanding of immunometabolism. We discuss the characteristics of chronic inflammation in the major metabolic tissues and how obesity triggers these events, including a focus on the role of adipose tissue hypoxia and macrophage-derived exosomes. Last, we also review current and potential new therapeutic strategies based on immunomodulation.

Barcode sequencing and a high-throughput assay for chronological lifespan uncover ageing-associated genes in fission yeast

Ageing-related processes are largely conserved, with simple organisms remaining the main platform to discover and dissect new ageing-associated genes. Yeasts provide potent model systems to study cellular ageing owing their amenability to systematic functional assays under controlled conditions. Even with yeast cells, however, ageing assays can be laborious and resource-intensive. Here we present improved experimental and computational methods to study chronological lifespan in Schizosaccharomyces pombe. We decoded the barcodes for 3206 mutants of the latest gene-deletion library, enabling the parallel profiling of ~700 additional mutants compared to previous screens. We then applied a refined method of barcode sequencing (Bar-seq), addressing technical and statistical issues raised by persisting DNA in dead cells and sampling bottlenecks in aged cultures, to screen for mutants showing altered lifespan during stationary phase. This screen identified 341 long-lived mutants and 1246 short-lived mutants which point to many previously unknown ageing-associated genes, including 46 conserved but entirely uncharacterized genes. The ageing-associated genes showed coherent enrichments in processes also associated with human ageing, particularly with respect to ageing in non-proliferative brain cells. We also developed an automated colony-forming unit assay to facilitate medium- to high-throughput chronological-lifespan studies by saving time and resources compared to the traditional assay. Results from the Bar-seq screen showed good agreement with this new assay. This study provides an effective methodological platform and identifies many new ageing-associated genes as a framework for analysing cellular ageing in yeast and beyond.

Dooming Phagocyte Responses: Inflammatory Effects of Endogenous Oxidized Phospholipids

Endogenous oxidized phospholipids are produced during tissue stress and are responsible for sustaining inflammatory responses in immune as well as non-immune cells. Their local and systemic production and accumulation is associated with the etiology and progression of several inflammatory diseases, but the molecular mechanisms that underlie the biological activities of these oxidized phospholipids remain elusive. Increasing evidence highlights the ability of these stress mediators to modulate cellular metabolism and pro-inflammatory signaling in phagocytes, such as macrophages and dendritic cells, and to alter the activation and polarization of these cells. Because these immune cells serve a key role in maintaining tissue homeostasis and organ function, understanding how endogenous oxidized lipids reshape phagocyte biology and function is vital for designing clinical tools and interventions for preventing, slowing down, or resolving chronic inflammatory disorders that are driven by phagocyte dysfunction. Here, we discuss the metabolic and signaling processes elicited by endogenous oxidized lipids and outline new hypotheses and models to elucidate the impact of these lipids on phagocytes and inflammation.

Cholesterol Metabolites 25-Hydroxycholesterol and 25-Hydroxycholesterol 3-Sulfate Are Potent Paired Regulators: From Discovery to Clinical Usage

Oxysterols have long been believed to be ligands of nuclear receptors such as liver × receptor (LXR), and they play an important role in lipid homeostasis and in the immune system, where they are involved in both transcriptional and posttranscriptional mechanisms. However, they are increasingly associated with a wide variety of other, sometimes surprising, cell functions. Oxysterols have also been implicated in several diseases such as metabolic syndrome. Oxysterols can be sulfated, and the sulfated oxysterols act in different directions: they decrease lipid biosynthesis, suppress inflammatory responses, and promote cell survival. Our recent reports have shown that oxysterol and oxysterol sulfates are paired epigenetic regulators, agonists, and antagonists of DNA methyltransferases, indicating that their function of global regulation is through epigenetic modification. In this review, we explore our latest research of 25-hydroxycholesterol and 25-hydroxycholesterol 3-sulfate in a novel regulatory mechanism and evaluate the current evidence for these roles.

Targeting metabolic pathways for extension of lifespan and healthspan across multiple species

Metabolism plays a significant role in the regulation of aging at different levels, and metabolic reprogramming represents a major driving force in aging. Metabolic reprogramming leads to impaired organismal fitness, an age-dependent increase in susceptibility to diseases, decreased ability to mount a stress response, and increased frailty. The complexity of age-dependent metabolic reprogramming comes from the multitude of levels on which metabolic changes can be connected to aging and regulation of lifespan. This is further complicated by the different metabolic requirements of various tissues, cross-organ communication via metabolite secretion, and direct effects of metabolites on epigenetic state and redox regulation; however, not all of these changes are causative to aging. Studies in yeast, flies, worms, and mice have played a crucial role in identifying mechanistic links between observed changes in various metabolic traits and their effects on lifespan. Here, we review how changes in the organismal and organ-specific metabolome are associated with aging and how targeting of any one of over a hundred different targets in specific metabolic pathways can extend lifespan. An important corollary is that restriction or supplementation of different metabolites can change activity of these metabolic pathways in ways that improve healthspan and extend lifespan in different organisms. Due to the high levels of conservation of metabolism in general, translating findings from model systems to human beings will allow for the development of effective strategies for human health- and lifespan extension.

Effect of Korean Red Ginseng on Cholesterol Metabolites in Postmenopausal Women with Hypercholesterolemia: A Pilot Randomized Controlled Trial

Korean red ginseng (KRG) is known to exert beneficial effects on cardiovascular health. Meanwhile, reduced estrogen at menopause has been shown to have various adverse impacts on cardiovascular risk factors, including blood lipids. The aim of this pilot study was to investigate the effect of KRG on cholesterol metabolites, which are surrogate markers of cholesterol absorption and biosynthesis, in postmenopausal women with hypercholesterolemia. The present study is an exploratory study which used data from a 4-week, double-blinded, placebo-controlled clinical pilot study in 68 postmenopausal women with hypercholesterolemia. Patients received KRG (2 g) or placebo (2 g) once daily. The primary endpoints were changes in the levels of nine sterols. Serum sterols were analyzed using liquid chromatography-mass spectrometry (LC-MS)/MS analysis. Among the sterols, reduction in cholesterol level were significantly larger in the KRG group than in the placebo group (the changes: −148.3 ± 261.1 nmol/mL in the ginseng group vs. −23.0 ± 220.5 nmol/mL in the placebo group, p = 0.039). Additionally, changes in 7-hydroxycholesterol (7-OHC) were significantly larger in the KRG group than in the placebo group (the changes: −0.05 ± 0.09 nmol/mL in the ginseng group vs. −0.002 ± 0.1 nmol/mL in the placebo group, p = 0.047). Oxysterols, cholesterol derivates, have been known to play a role in chronic inflammation diseases such as cardiovascular diseases. KRG improves sterol metabolism by decreasing cholesterol and 7-OHC levels in postmenopausal women with hypercholesterolemia.

Multi-dimensional characterization and identification of sterols in untargeted LC-MS analysis using all ion fragmentation technology

Sterols are an important type of lipids, and play many important roles in physiological and pathological processes. However, comprehensive analysis of sterols especially identification of unknown sterols is challenging. In this work, LC-MS with all ion fragmentation (AIF) technology was developed for untargeted analysis of sterols in biological samples. AIF technology provided holistic and multi-dimensional characterization for both knowns and unknowns sterols, including accurate m/z, isotope pattern, retention time (RT), and co-eluted peak profiles between MS1 and MS2 ions in one analysis. We further developed an analysis strategy by integrating the multi-dimensional properties to support unambiguous identification of sterols, including distinguishing sterol isomers. The developed strategy enabled to identify a total of 23 sterols in mouse samples, and quantified 19 sterols in mouse liver tissues. More importantly, we demonstrated that AIF based multi-dimensional analysis provided a possibility to identify sterols without chemical standards and facilitated to discover novel compounds with sterol-like structures in biological samples. In summary, we employed the LC-MS based AIF technology to develop multi-dimensional characterization and identification of both known and unknown sterols in complex biological samples. The comprehensive analysis of sterols facilitates to provide molecular insights to many physiological and pathological activities in biology.

The Molecular Language of the Cnidarian-Dinoflagellate Symbiosis

The cnidarian-dinoflagellate symbiosis is of huge importance as it underpins the success of coral reefs, yet we know very little about how the host cnidarian and its dinoflagellate endosymbionts communicate with each other to form a functionally integrated unit. Here, we review the current knowledge of interpartner molecular signaling in this symbiosis, with an emphasis on lipids, glycans, reactive species, biogenic volatiles, and noncoding RNA. We draw upon evidence of these compounds from recent omics-based studies of cnidarian-dinoflagellate symbiosis and discuss the signaling roles that they play in other, better-studied symbioses. We then consider how improved knowledge of interpartner signaling might be used to develop solutions to the coral reef crisis by, for example, engineering more thermally resistant corals.

The bacterial quorum sensing signal DSF hijacks Arabidopsis thaliana sterol biosynthesis to suppress plant innate immunity

Quorum sensing (QS) is a recognized phenomenon that is crucial for regulating population-related behaviors in bacteria. However, the direct specific effect of QS molecules on host biology is largely understudied. In this work, we show that the QS molecule DSF (cis-11-methyl-dodecenoic acid) produced by Xanthomonas campestris pv. campestris can suppress pathogen-associated molecular pattern-triggered immunity (PTI) in Arabidopsis thaliana, mediated by flagellin-induced activation of flagellin receptor FLS2. The DSF-mediated attenuation of innate immunity results from the alteration of FLS2 nanoclusters and endocytic internalization of plasma membrane FLS2. DSF altered the lipid profile of Arabidopsis, with a particular increase in the phytosterol species, which impairs the general endocytosis pathway mediated by clathrin and FLS2 nano-clustering on the plasma membrane. The DSF effect on receptor dynamics and host immune responses could be entirely reversed by sterol removal. Together, our results highlighted the importance of sterol homeostasis to plasma membrane organization and demonstrate a novel mechanism by which pathogenic bacteria use their communicating molecule to manipulate pathogen-associated molecular pattern-triggered host immunity.

The bacterial quorum sensing signal DSF hijacks Arabidopsis thaliana sterol biosynthesis to suppress plant innate immunity

Quorum sensing (QS) is a recognized phenomenon that is crucial for regulating population-related behaviors in bacteria. However, the direct specific effect of QS molecules on host biology is largely understudied. In this work, we show that the QS molecule DSF (cis-11-methyl-dodecenoic acid) produced by Xanthomonas campestris pv. campestris can suppress pathogen-associated molecular pattern-triggered immunity (PTI) in Arabidopsis thaliana, mediated by flagellin-induced activation of flagellin receptor FLS2. The DSF-mediated attenuation of innate immunity results from the alteration of FLS2 nanoclusters and endocytic internalization of plasma membrane FLS2. DSF altered the lipid profile of Arabidopsis, with a particular increase in the phytosterol species, which impairs the general endocytosis pathway mediated by clathrin and FLS2 nano-clustering on the plasma membrane. The DSF effect on receptor dynamics and host immune responses could be entirely reversed by sterol removal. Together, our results highlighted the importance of sterol homeostasis to plasma membrane organization and demonstrate a novel mechanism by which pathogenic bacteria use their communicating molecule to manipulate pathogen-associated molecular pattern-triggered host immunity.

Regulation of cellular sterol homeostasis by the oxygen responsive noncoding RNA lincNORS

We hereby provide the initial portrait of lincNORS, a spliced lincRNA generated by the MIR193BHG locus, entirely distinct from the previously described miR-193b-365a tandem. While inducible by low O₂ in a variety of cells and associated with hypoxia in vivo, our studies show that lincNORS is subject to multiple regulatory inputs, including estrogen signals. Biochemically, this lincRNA fine-tunes cellular sterol/steroid biosynthesis by repressing the expression of multiple pathway components. Mechanistically, the function of lincNORS requires the presence of RALY, an RNA-binding protein recently found to be implicated in cholesterol homeostasis. We also noticed the proximity between this locus and naturally occurring genetic variations highly significant for sterol/steroid-related phenotypes, in particular the age of sexual maturation. An integrative analysis of these variants provided a more formal link between these phenotypes and lincNORS, further strengthening the case for its biological relevance.

Gender Differential Transcriptome in Gastric and Thyroid Cancers

Cancer has an important and considerable gender differential susceptibility confirmed by several epidemiological studies. Gastric (GC) and thyroid cancer (TC) are examples of malignancies with a higher incidence in males and females, respectively. Beyond environmental predisposing factors, it is expected that gender-specific gene deregulation contributes to this differential incidence. We performed a detailed characterization of the transcriptomic differences between genders in normal and tumor tissues from stomach and thyroid using Genotype-Tissue Expression (GTEx) and The Cancer Genome Atlas (TCGA) data. We found hundreds of sex-biased genes (SBGs). Most of the SBGs shared by normal and tumor belong to sexual chromosomes, while the normal and tumor-specific tend to be found in the autosomes. Expression of several cancer-associated genes is also found to differ between sexes in both types of tissue. Thousands of differentially expressed genes (DEGs) between paired tumor-normal tissues were identified in GC and TC. For both cancers, in the most susceptible gender, the DEGs were mostly under-expressed in the tumor tissue, with an enrichment for tumor-suppressor genes (TSGs). Moreover, we found gene networks preferentially associated to males in GC and to females in TC and correlated with cancer histological subtypes. Our results shed light on the molecular differences and commonalities between genders and provide novel insights in the differential risk underlying these cancers.

CRISPR/Cas9 knockout of human arylamine N-acetyltransferase 1 in MDA-MB-231 breast cancer cells suggests a role in cellular metabolism

Human arylamine N-acetyltransferase 1 (NAT1), present in all tissues, is classically described as a phase-II xenobiotic metabolizing enzyme but can also catalyze the hydrolysis of acetyl-Coenzyme A (acetyl-CoA) in the absence of an arylamine substrate using folate as a cofactor. NAT1 activity varies inter-individually and has been shown to be overexpressed in estrogen receptor-positive (ER+) breast cancers. NAT1 has also been implicated in breast cancer progression however the exact role of NAT1 remains unknown. The objective of this study was to evaluate the effect of varying levels of NAT1 N-acetylation activity in MDA-MB-231 breast cancer cells on global cellular metabolism and to probe for unknown endogenous NAT1 substrates. Global, untargeted metabolomics was conducted via ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) on MDA-MB-231 breast cancer cell lines constructed with siRNA and CRISPR/Cas9 technologies to vary only in NAT1 N-acetylation activity. Many metabolites were differentially abundant in NAT1-modified cell lines compared to the Scrambled parental cell line. N-acetylasparagine and N-acetylputrescine abundances were strongly positively correlated (r = 0.986 and r = 0.944, respectively) with NAT1 N-acetylation activity whereas saccharopine abundance was strongly inversely correlated (r = −0.876). Two of the most striking observations were a reduction in de novo pyrimidine biosynthesis and defective β-oxidation of fatty acids in the absence of NAT1. We have shown that NAT1 expression differentially affects cellular metabolism dependent on the level of expression. Our results support the hypothesis that NAT1 is not just a xenobiotic metabolizing enzyme and may have a role in endogenous cellular metabolism.

Effect of compromised liver function and acute kidney injury on the pharmacokinetics of thymoquinone in a rat model

The current research explored the effect of hepatic and renal dysfunctions on the pharmacokinetics of thymoquinone (TQ) in a rat model.An acute kidney injury was induced using gentamicin and a liver damage was elicited using a single dose of d-galactosamine. For the pharmacokinetic studies, TQ was administered as IV injection or and PO route to rats.The concentrations of TQ and pharmacokinetic parameters were calculated using a non-compartmental analysis. The systemic clearance (Cl) of TQ after IV dosing was slightly reduced in the liver dysfunction group compared to healthy controls (p = 0.0013). Similarly, the estimated volume of distribution at steady state (Vss) was marginally decreased (p = 0.001). However, in rats with acute kidney injury exhibited a larger Vss as opposed to normal renal function (511.28 ± 21.03 ml/kg vs. 442.25 ± 31.43 ml/kg; p = 0.0001). Whereas oral Cl and terminal volume of distribution (Vz) of TQ were reduced by ∼50% in the liver dysfunction group (p = 0.0001). These changes were associated with more systemic exposure as measured by AUC_0-∞ in rats with compromised liver functions. The estimated plasma protein binding TQ was 99.84 ± 0.03% in healthy controls, 97.05 ± 0.57% with kidney injury rats, and 95.75 ± 0.64% in liver dysfunctionThe findings of the present study suggest that liver dysfunction could potentially modify the disposition of TQ administered orally, and therefore, a smaller maintenance dose is probably required to avoid accumulation.

Triglyceride deficiency and diacylglycerol kinase1 activity lead to the upregulation of mevalonate pathway in yeast: A study for the development of potential yeast platform for improved production of triterpenoid

Besides energy storage and membrane biogenesis, lipids are known for their numerous biological functions. The two essential lipids, diacylglycerol (DG) and phosphatidic acid (PA), are shown to be associated with cell signalling processes. In this study, we examined whether triglyceride-deficient yeast mutants (tgΔ), dga1Δ and dga1Δlro1Δ, may play an important role in mevalonate (MEV) pathway regulation. Our metabolite analyses revealed that tgΔ cells showed high levels of squalene (SQ) and ergosterol (ERG), which are key indicators of MEV pathway activity. In addition, gene expression studies indicated that the MEV pathway genes in tgΔ cells were significantly upregulated. Interestingly, tgΔ cells exhibited high diacylglycerol kinase1 (DGK1) expression. Furthermore, DGK1 overexpression in WT and tgΔ phenotypes causes a substantial elevation in SQ and ERG levels, and we also found a significant increase in transcript levels of MEV pathway genes, confirming the new role of DGK1 in MEV pathway regulation. This suggests that high DG phosphorylation activity increases the PA pool that may induce the upregulation of MEV pathway in tgΔ cells. The induced MEV pathway is one of the key strategies in the field of synthetic biology for improved production of terpenoids in yeast. Thus, to examine whether increased endogenous MEV pathway flux can be redirected to triterpenoid, β-Amyrin synthase gene was heterologously expressed in DGK1 overexpressing tgΔ cells that led to significant production of β-Amyrin, a natural triterpenoid. In conclusion, our findings provide a novel strategy to increase MEV pathway precursors by modulating endogenous signal lipids for improved production of terpenoids.

Relationship Between the Gastrointestinal Side Effects of an Anti-Hypertensive Medication and Changes in the Serum Lipid Metabolome

An earlier study using a rat model system indicated that the active ingredients contained in the anti-hypertensive medication amlodipine (AMD) appeared to induce various bowel problems, including constipation and inflammation. A probiotic blend was found to alleviate intestinal complications caused by the medicine. To gain more extensive insight into the beneficial effects of the probiotic blend, we investigated the changes in metabolite levels using a non-targeted metabolic approach with ultra-performance liquid chromatography-quadrupole/time-of-fligh (UPLC-q/TOF) mass spectrometry. Analysis of lipid metabolites revealed that rats that received AMD had a different metabolome profile compared with control rats and rats that received AMD plus the probiotic blend. In the AMD-administered group, serum levels of phosphatidylcholines, lysophosphatidylcholines, sphingomyelins, triglycerides with large numbers of double bonds, cholesterols, sterol derivatives, and cholesterol esters (all p < 0.05) were increased compared with those of the control group and the group that received AMD plus the probiotic blend. The AMD-administered group also exhibited significantly decreased levels of triglycerides with small numbers of double bonds (all p < 0.05). These results support our hypothesis that AMD-induced compositional changes in the gut microbiota are a causal factor in inflammation.

Steryl Ester Formation and Accumulation in Steroid-Degrading Bacteria

Steryl esters (SEs) are important storage compounds in many eukaryotes and are often prominent components of intracellular lipid droplets. Here, we demonstrate that selected Actino- and Proteobacteria growing on sterols are also able to synthesize SEs and to sequester them in cytoplasmic lipid droplets. We found cholesteryl ester (CE) formation in members of the actinobacterial genera Rhodococcus, Mycobacterium, and Amycolatopsis, as well as several members of the proteobacterial Cellvibrionales order. CEs maximally accumulated under nitrogen-limiting conditions, suggesting that steryl ester formation plays a crucial role for storing excess energy and carbon under adverse conditions. Rhodococcus jostii RHA1 was able to synthesize phytosteryl and cholesteryl esters, the latter reaching up to 7% of its cellular dry weight and 69% of its lipid droplets. Purified lipid droplets from RHA1 contained CEs, free cholesterol, and triacylglycerols. In addition, we found formation of CEs in Mycobacterium tuberculosis when it was grown with cholesterol plus an additional fatty acid substrate. This study provides a basis for the application of bacterial whole-cell systems in the biotechnological production of SEs for use in functional foods and cosmetics.IMPORTANCE Oleaginous bacteria exhibit great potential for the production of high-value neutral lipids, such as triacylglycerols and wax esters. This study describes the formation of steryl esters (SEs) as neutral lipid storage compounds in sterol-degrading oleaginous bacteria, providing a basis for biotechnological production of SEs using bacterial systems with potential applications in the functional food, nutraceutical, and cosmetic industries. We found cholesteryl ester (CE) formation in several sterol-degrading Actino- and Proteobacteria under nitrogen-limiting conditions, suggesting an important role of this process in storing energy and carbon under adverse conditions. In addition, Mycobacterium tuberculosis grown on cholesterol accumulated CEs in the presence of an additional fatty acid substrate.