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Ferroptosis, an iron-dependent regulated cell death, is implicated in several diseases, including cancer and neurodegeneration. While most ferroptosis inhibitors act as radical-trapping antioxidants, direct modulation of pro-ferroptotic enzymes remains underexplored. Acyl-coenzyme A synthetase long-chain family member 4 (ACSL4), a key regulator of ferroptosis, has emerged as a promising therapeutic target. Here, we report a fragment-based screening that identified a benzofuran hit (compound 8, IC₅₀ = 33 μM), leading to the discovery of two selective ACSL4 inhibitors: compound 15b (LIBX-A402, IC₅₀ = 0.33 μM) and compound 21 (LIBX-A403, IC₅₀ = 0.049 μM). Compound 21 is the most potent ACSL4 inhibitor reported to date and shows no activity against ACSL3. Molecular modeling and mutagenesis support its binding in the ACSL4 fatty acid pocket. The strong antiferroptotic activity of both compounds in cells, together with confirmed target engagement for 21, underscores the relevance of ACSL4 as a target for ferroptosis modulation. Show less

Researchers are using new molecules, engineered immune cells and gene therapy to kill senescent cells and treat age-related diseases. Researchers are using new molecules, engineered immune cells and gene therapy to kill senescent cells and treat age-related diseases. Show less

Oxidation-reduction (redox) reactions are central to the existence of life. Reactive species of oxygen, nitrogen and sulfur mediate redox control of a wide range of essential cellular processes. Yet, excessive levels of oxidants are associated with ageing and many diseases, including cardiological and neurodegenerative diseases, and cancer. Hence, maintaining the fine-tuned steady-state balance of reactive species production and removal is essential. Here, we discuss new insights into the dynamic maintenance of redox homeostasis (that is, redox homeodynamics) and the principles underlying biological redox organization, termed the 'redox code'. We survey how redox changes result in stress responses by hormesis mechanisms, and how the lifelong cumulative exposure to environmental agents, termed the 'exposome', is communicated to cells through redox signals. Better understanding of the molecular and cellular basis of redox biology will guide novel redox medicine approaches aimed at preventing and treating diseases associated with disturbed redox regulation. Show less

Cells tend to disintegrate themselves or are forced to undergo such destructive processes in critical circumstances. This complex cellular function necessitates various mechanisms and molecular pathways in order to be executed. The very nature of cell death is essentially important and vital for maintaining homeostasis, thus any type of disturbing occurrence might lead to different sorts of diseases and dysfunctions. Cell death has various modalities and yet, every now and then, a new type of this elegant procedure gets to be discovered. The diversity of cell death compels the need for a universal organizing system in order to facilitate further studies, therapeutic strategies and the invention of new methods of research. Considering all that, we attempted to review most of the known cell death mechanisms and sort them all into one arranging system that operates under a simple but subtle decision-making (If \ Else) order as a sorting algorithm, in which it decides to place and sort an input data (a type of cell death) into its proper set, then a subset and finally a group of cell death. By proposing this algorithm, the authors hope it may solve the problems regarding newer and/or undiscovered types of cell death and facilitate research and therapeutic applications of cell death. Show less

Apoptosis is a form of regulated cell death (RCD) that involves proteases of the caspase family. Pharmacological and genetic strategies that experimentally inhibit or delay apoptosis in mammalian systems have elucidated the key contribution of this process not only to (post-)embryonic development and adult tissue homeostasis, but also to the etiology of multiple human disorders. Consistent with this notion, while defects in the molecular machinery for apoptotic cell death impair organismal development and promote oncogenesis, the unwarranted activation of apoptosis promotes cell loss and tissue damage in the context of various neurological, cardiovascular, renal, hepatic, infectious, neoplastic and inflammatory conditions. Here, the Nomenclature Committee on Cell Death (NCCD) gathered to critically summarize an abundant pre-clinical literature mechanistically linking the core apoptotic apparatus to organismal homeostasis in the context of disease. Show less

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institutes of Health (NIH) Introduction The prevalence of obesity continues to rise to unprecedented levels, and with it, a corresponding increase in the incidence of cardiovascular disease (CVD). While obesity is indeed accepted as one of the most prominent risk factors for CVD, the precise molecular mechanisms by which aberrant metabolism is linked to cardiovascular function remain incompletely understood. One prevailing hypothesis is that overproduction of reactive oxygen species (ROS) from increased metabolism significantly contributes to endothelial dysfunction, which precedes many cardiovascular events such as atherosclerosis and stroke. Purpose In this study, we hypothesized that a receptor for advanced glycation end products, Galectin-3 (GAL3), acts as a metabolic sensor and regulates endothelial ROS production in obesity. Methods Obese db/db mice were crossed with mice lacking GAL3, and endothelial gene expression, microvascular reactivity, and ROS production were assessed. Results We demonstrate that NADPH Oxidase I (NOX1), the predominant source of endothelial superoxide production, is down-regulated by GAL3 deletion, thereby rescuing endothelial function and ameliorating endothelial ROS production in obesity. Furthermore, we demonstrate that GAL3-mediated NOX1 over-expression is amenable to improvements in metabolic status, such as lowering blood glucose with metformin, improving glucose handling by augmenting muscle mass, or improving insulin signaling through deletion of Protein Tyrosine Phosphatase 1B (PTP1B). Conclusion Taken together, these data demonstrate that the overproduction of superoxide by endothelial NOX1 is regulated by the metabolic sensor GAL3 in obesity, leading to endothelial dysfunction and CVD. This pathway presents an attractive target for therapeutic intervention to break the link between aberrant metabolism in obesity and its corresponding vascular pathologies. Show less

The methylation of arginine residues regulates gene expression, DNA repair, growth factor signalling and liquid–liquid phase separation. Targeting this modification can thus be therapeutically relevant and inhibitors of arginine methylation are being tested in clinical trials, especially for neurodegenerative diseases and cancer. Show less

AIMS: Gastro-resistant dimethyl fumarate (DMF) is an oral therapeutic indicated for the treatment of relapsing multiple sclerosis. Recent data suggest that a primary pharmacodynamic response to DMF treatment is activation of the nuclear factor (erythroid-derived 2)-like 2 (NRF2) pathway; however, the gene targets modulated downstream of NRF2 that contribute to DMF-dependent effects are poorly understood. RESULTS: Using wild-type and NRF2 knockout mice, we characterized DMF transcriptional responses throughout the brain and periphery to understand DMF effects in vivo and to explore the necessity of NRF2 in this process. Our findings identified tissue-specific expression of NRF2 target genes as well as NRF2-dependent and -independent gene regulation after DMF administration. Furthermore, using gene ontology, we identified common biological pathways that may be regulated by DMF and contribute to in vivo functional effects. INNOVATION: Together, these data suggest that DMF modulates transcription through multiple pathways, which has implications for the cytoprotective, immunomodulatory, and clinical properties of DMF. CONCLUSION: These findings provide further understanding of the DMF mechanism of action and propose potential therapeutic targets that warrant further investigation for treating neurodegenerative diseases. Antioxid. Redox Signal. 24, 1058-1071. Show less

The specific autophagic elimination of mitochondria (mitophagy) plays the role of quality control for this organelle. Deregulation of mitophagy leads to an increased number of damaged mitochondria and triggers cell death. The deterioration of mitophagy has been hypothesized to underlie the pathogenesis of several neurodegenerative diseases, most notably Parkinson disease. Although some of the biochemical and molecular mechanisms of mitochondrial quality control are described in detail, physiological or pathological triggers of mitophagy are still not fully characterized. Here we show that the induction of mitophagy by the mitochondrial uncoupler FCCP is independent of the effect of mitochondrial membrane potential but dependent on acidification of the cytosol by FCCP. The ionophore nigericin also reduces cytosolic pH and induces PINK1/PARKIN-dependent and -independent mitophagy. The increase of intracellular pH with monensin suppresses the effects of FCCP and nigericin on mitochondrial degradation. Thus, a change in intracellular pH is a regulator of mitochondrial quality control. Show less

The regulation of hydrogen ion concentration (pH) is fundamental to cell viability, metabolism, and enzymatic function. Within the nervous system, the control of pH is also involved in diverse and dynamic processes including development, synaptic transmission, and the control of network excitability. As pH affects neuronal activity, and can also itself be altered by neuronal activity, the existence of tools to accurately measure hydrogen ion fluctuations is important for understanding the role pH plays under physiological and pathological conditions. Outside of their use as a marker of synaptic release, genetically encoded pH sensors have not been utilized to study hydrogen ion fluxes associated with network activity. By combining whole-cell patch clamp with simultaneous two-photon or confocal imaging, we quantified the amplitude and time course of neuronal, intracellular, acidic transients evoked by epileptiform activity in two separate in vitro models of temporal lobe epilepsy. In doing so, we demonstrate the suitability of three genetically encoded pH sensors: deGFP4, E(2)GFP, and Cl-sensor for investigating activity-dependent pH changes at the level of single neurons. Show less