Cell death programs such as apoptosis and ferroptosis are associated with aberrant redox homeostasis linked to lipid metabolism and membrane function. Evidence for cross-talk between these programs is emerging. Here, we show that cytotoxic stress channels polyunsaturated fatty acids via lysophospholipid acyltransferase 12 into phospholipids that become susceptible to peroxidation under additional redox stress. This reprogramming is associated with altered acyl-CoA synthetase isoenzyme expression and caused by a decrease in growth factor receptor tyrosine kinase (RTK)-phosphatidylinositol-3-kinase signaling, resulting in suppressed fatty acid biosynthesis, for specific stressors via impaired Akt-SREBP1 activation. The reduced availability of de novo synthesized fatty acids favors the channeling of polyunsaturated fatty acids into phospholipids. Growth factor withdrawal by serum starvation mimics this phenotype, whereas RTK ligands counteract it. We conclude that attenuated RTK signaling during cell death initiation increases cells’ susceptibility to oxidative membrane damage at the interface of apoptosis and alternative cell death programs.

Rationale: Silybum marianum is used to protect against degenerative liver damage. The molecular mechanisms of its bioactive component, silybin, remained enigmatic, although membrane-stabilizing properties, modulation of membrane protein function, and metabolic regulation have been discussed for decades. Methods: Experiments were performed with hepatocyte cell lines and primary monocytes in vitro under both basal and stressed conditions, and in mice in vivo. Quantitative lipidomics was used to detect changes in phospholipids and triglycerides. Key findings were confirmed by Western blotting, quantitative PCR, microscopy, enzyme activity assays, metabolic flux studies, and functional relationships were investigated using selective inhibitors. Results: We show that specifically the stereoisomer silybin A decreases triglyceride levels and lipid droplet content, while enriching major phospholipid classes and maintaining a homeostatic phospholipid composition in human hepatocytes in vitro and in mouse liver in vivo under normal and pre-disease conditions. Conversely, in cell-based disease models of lipid overload and lipotoxic stress, silybin treatment primarily depletes triglycerides. Mechanistically, silymarin/silybin suppresses phospholipid-degrading enzymes, induces phospholipid biosynthesis to varying degrees depending on the conditions, and down-regulates triglyceride remodeling/biosynthesis, while inducing complex changes in sterol and fatty acid metabolism. Structure-activity relationship studies highlight the importance of the 1,4-benzodioxane ring configuration of silybin A in triglyceride reduction and the saturated 2,3-bond of the flavanonol moiety in phospholipid accumulation. Enrichment of hepatic phospholipids and intracellular membrane expansion are associated with a heightened biotransformation capacity. Conclusion: Our study deciphers the structural features of silybin contributing to hepatic lipid remodeling and suggests that silymarin/silybin protects the liver in individuals with mild metabolic dysregulation, involving a lipid class switch from triglycerides to phospholipids, whereas it may be less effective in disease states associated with severe metabolic dysregulation.

Therapy resistance and metastasis, the most fatal steps in cancer, are often triggered by a (partial) activation of the epithelial-mesenchymal transition (EMT) programme. A mesenchymal phenotype predisposes to ferroptosis, a cell death pathway exerted by an iron and oxygen-radical-mediated peroxidation of phospholipids containing polyunsaturated fatty acids. We here show that various forms of EMT activation, including TGF beta stimulation and acquired therapy resistance, increase ferroptosis susceptibility in cancer cells, which depends on the EMT transcription factor Zeb1. We demonstrate that Zeb1 increases the ratio of phospholipids containing pro-ferroptotic polyunsaturated fatty acids over cyto-protective monounsaturated fatty acids by modulating the differential expression of the underlying crucial enzymes stearoyl-Co-A desaturase 1 (SCD), fatty acid synthase (FASN), fatty acid desaturase 2 (FADS2), elongation of very long-chain fatty acid 5 (ELOVL5) and long-chain acyl-CoA synthetase 4 (ACSL4). Pharmacological inhibition of selected lipogenic enzymes (SCD and FADS2) allows the manipulation of ferroptosis sensitivity preferentially in high-Zeb1-expressing cancer cells. Our data are of potential translational relevance and suggest a combination of ferroptosis activators and SCD inhibitors for the treatment of aggressive cancers expressing high Zeb1. Schwab, Rao et al. report that Zeb1 mediates enhanced ferroptosis sensitivity in cancer cells after EMT activation, associated with altered expression of selected lipogenic enzymes and an subsequent increase in the PUFA:MUFA ratio.

Atopic dermatitis (AD) is a highly prevalent chronic skin disease. Anti-inflammatory and antipruritic emollients (emollients plus) with excellent cosmetic properties may alleviate AD-related symptoms and reduce the number of exacerbations. To screen for herbal extracts with potent anti-inflammatory and antioxidative potential in human skin cell cultures. Ginger extract and synthetic cannabidiol (CBD) were identified and combined in the cosmetic product BNO 3731, which was evaluated in a randomized clinical trial. Preclinical: anti-inflammatory effects of ginger extract, synthetic CBD and a combination thereof were evaluated in human skin cell cultures by analysing nuclear factor κB activation, release of inflammatory cytokines and endocannabinoid production. Clinical: BNO 3731 was studied in a clinical trial comprising 44 AD patients (adults and children) and compared to a benchmark product over a treatment duration of five days. Symptom severity was evaluated by objective and subjective dermatological assessments as well as physiological skin parameters. Itch intensity was assessed using a numerical rating scale (NRS-11). Preclinical: Ginger extract and synthetic CBD exhibited potent anti-inflammatory and antioxidative effects in vitro which were associated with elevated concentrations of the endocannabinoid, anandamide. Clinical: BNO 3731 significantly alleviated symptoms of AD and improved physiological skin parameters. Itch intensity decreased significantly by 55%, and in 75% of subjects, itch improved ≥2 points on the NRS-11 scale. No adverse events were reported. BNO 3731, containing a unique synergistic combination of ginger extract and synthetic CBD, is an effective and safe treatment option for dry and eczema-prone skin, providing rapid and substantial relief of pruritus.

Proteomics and metabolomics are essential in systems biology, and simultaneous proteo-metabolome liquid-liquid extraction (SPM-LLE) allows isolation of the metabolome and proteome from the same sample. Since the proteome is present as a pellet in SPM-LLE, it must be solubilized for quantitative proteomics. Solubilization and proteome extraction are critical factors in the information obtained at the proteome level. In this study, we investigated the performance of two surfactants (sodium deoxycholate (SDC), sodium dodecyl sulfate (SDS)) and urea in terms of proteome coverage and extraction efficiency of an interphase proteome pellet generated by methanol-chloroform based SPM-LLE. We also investigated how the performance differs when the proteome is extracted from the interphase pellet or by direct cell lysis. We quantified 12 lipids covering triglycerides and various phospholipid classes, and 25 polar metabolites covering central energy metabolism in chloroform and methanol extracts. Our study reveals that the proteome coverages between the two surfactants and urea for the SPM-LLE interphase pellet were similar, but the extraction efficiencies differed significantly. While SDS led to enrichment of basic proteins, which were mainly ribosomal and ribonuclear proteins, urea was the most efficient extraction agent for simultaneous proteo-metabolome analysis. The results of our study also show that the performance of surfactants for quantitative proteomics is better when the proteome is extracted through direct cell lysis rather than an interphase pellet. In contrast, the performance of urea for quantitative proteomics was significantly better when the proteome was extracted from an interphase pellet than by direct cell lysis. We demonstrated that urea is superior to surfactants for proteome extraction from SPM-LLE interphase pellets, with a particularly good performance for the extraction of proteins associated with metabolic pathways. Data are available via ProteomeXchange with identifier PXD027338.

Cytotoxic stress activates stress-activated kinases, initiates adaptive mechanisms, including the unfolded protein response (UPR) and autophagy, and induces programmed cell death. Fatty acid unsaturation, controlled by stearoyl-CoA desaturase (SCD)1, prevents cytotoxic stress but the mechanisms are diffuse. Here, we show that 1,2-dioleoyl- sn -glycero-3-phospho-(1’-myo-inositol) [PI(18:1/18:1)] is a SCD1-derived signaling lipid, which inhibits p38 mitogen-activated protein kinase activation, counteracts UPR, endoplasmic reticulum-associated protein degradation, and apoptosis, regulates autophagy, and maintains cell morphology and proliferation. SCD1 expression and the cellular PI(18:1/18:1) proportion decrease during the onset of cell death, thereby repressing protein phosphatase 2 A and enhancing stress signaling. This counter-regulation applies to mechanistically diverse death-inducing conditions and is found in multiple human and mouse cell lines and tissues of Scd1 -defective mice. PI(18:1/18:1) ratios reflect stress tolerance in tumorigenesis, chemoresistance, infection, high-fat diet, and immune aging. Together, PI(18:1/18:1) is a lipokine that links fatty acid unsaturation with stress responses, and its depletion evokes stress signaling.

The coronavirus disease 2019 (COVID-19) has developed into a serious pandemic with millions of cases diagnosed worldwide. To fight COVID-19 pandemic, over 100 countries instituted either a full or partial lockdown, affecting billions of people. In Tyrol, first lockdown measures were taken on 10 March 2020. On 16 March 2020, a curfew went into force which ended on 1 May 2020. On 19 March 2020, Tyrol as a whole was placed in quarantine which ended on 7 April 2020. The governmental actions helped reducing the spread of COVID-19 at the cost of significant effects on social life and behaviour. Accordingly, to provide a comprehensive picture of the population health status not only input from medical and biological sciences is required, but also from other sciences able to provide lifestyle information such as drug use. Herein, wastewater-based epidemiology was used for studying temporal trends of licit and illicit drug consumption during lockdown and quarantine in the area of the Tyrolean capital Innsbruck (174,000 inhabitants). On 35 days between 12 March 2020 and 15 April 2020, loads of 23 markers were monitored in wastewater. Loads determined on 292 days between March 2016 and January 2020 served as reference. During lockdown, changes in the consumption patterns of recreational drugs (i.e. cocaine, amphetamine, 3,4-methylenedioxymethamphetamine, methamphetamine, and alcohol) and pharmaceuticals for short-term application (i.e. acetaminophen, codeine, and trimethoprim) were detected. For illicit drugs and alcohol, it is very likely that observed changes were linked to the shutdown of the hospitality industry and event cancelation which led to a reduced demand of these compounds particularly on weekends. For the pharmaceuticals, further work will be necessary to clarify if the observed declines are indicators of improved population health or of some kind of restraining effect that reduced the number of consultations of medical doctors and pharmacies.