Therapeutic approaches to metabolic syndrome (MetS) are numerous and may target lipoproteins, blood pressure or anthropometric indices. Peroxisome proliferator-activated receptors (PPARs) are involved in the metabolic regulation of lipid and lipoprotein levels, i.e., triglycerides (TGs), blood glucose, and abdominal adiposity. PPARs may be classified into the α, β/δ and γ subtypes. The PPAR-α agonists, mainly fibrates (including newer molecules such as pemafibrate) and omega-3 fatty acids, are powerful TG-lowering agents. They mainly affect TG catabolism and, particularly with fibrates, raise the levels of high-density lipoprotein cholesterol (HDL-C). PPAR-γ agonists, mainly glitazones, show a smaller activity on TGs but are powerful glucose-lowering agents. Newer PPAR-α/δ agonists, e.g., elafibranor, have been designed to achieve single drugs with TG-lowering and HDL-C-raising effects, in addition to the insulin-sensitizing and antihyperglycemic effects of glitazones. They also hold promise for the treatment of non-alcoholic fatty liver disease (NAFLD) which is closely associated with the MetS. The PPAR system thus offers an important hope in the management of atherogenic dyslipidemias, although concerns regarding potential adverse events such as the rise of plasma creatinine, gallstone formation, drug–drug interactions (i.e., gemfibrozil) and myopathy should also be acknowledged.

ach tissue has a specific composition of its extracellular matrix (ECM), which is associated with distinctive physical and mechanical properties. These mechanical properties are important for tissue structure, but also control cell function in physiology and disease 1,2. Cells sense the mechanical properties of the ECM through integrin receptors, and measure them by adjusting the contractility of their F-actin cytoskeleton: contractility is maximal when cells are free to spread on stiff ECM substrata, while it is progressively decreased on a soft ECM or in conditions of limited spreading 1. This is sufficient to control the switch between proliferation, differentiation and death in very diverse cell types, by regulating intracellular signalling pathways such as YAP (Yes-associated protein)/TAZ (transcriptional co-activator with PDZ-binding motif, also known as WWTR1) 3,4 and SRF (serum response factor) 5,6. In support of this model, inhibition of key players that maintain F-actin contractility including the small GTPase RHO, ROCK (RHO kinase), MLCK (myosin light chain kinase) and non-muscle myosin (NMII) induce similar responses to a soft ECM 1. Yet, which other general aspects of cell biology are regulated by mechanical cues, and through which mechanism(s), remain largely unexplored. This is especially true in the case of metabolism, a fundamental engine that is constantly remodelled to match the energetic and biosynthetic requirements of the cell, whose connections to mechanical cues are only starting to emerge 7,8. Results Actomyosin regulates lipid metabolism. To test in an unbiased manner the possibility that actomyosin contractility regulates metabolism we used global metabolomics to compare cells in conditions of high contractility (plated on plastics) with cells in conditions of low contractility, by inhibiting ROCK and MLCK. Analysis of steady-state levels of multiple metabolites indicated clear differences between controls and treated cells (Fig. 1a and Supplementary

Myelin is a membrane characterized by high lipid content to facilitate impulse propagation. Changes in myelin fatty acid (FA) composition have been associated with peripheral neuropathy, but the specific role of peripheral nerve FA synthesis in myelin formation and function is poorly understood. We have found that mice lacking sterol regulatory element-binding factor-1c (Srebf1c) have blunted peripheral nerve FA synthesis that results in development of peripheral neuropathy. Srebf1c-null mice develop Remak bundle alterations and hypermyelination of small-caliber fibers that impair nerve function. Peripheral nerves lacking Srebf1c show decreased FA synthesis and glycolytic flux, but increased FA catabolism and mitochondrial function. These metabolic alterations are the result of local accumulation of two endogenous peroxisome proliferator-activated receptor-α (Pparα) ligands, 1-palmitoyl-2-oleyl-sn-glycerol-3-phosphatidylcholine and 1-stearoyl-2-oleyl-sn-glycerol-3-phosphatidylcholine. Treatment with a Pparα antagonist rescues the neuropathy of Srebf1c-null mice. These findings reveal the importance of peripheral nerve FA synthesis to sustain myelin structure and function.

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In the last decades, lysosomes and mitochondria were considered distinct and physically separated organelles involved in different cellular functions. While lysosomes were thought to exclusively be the rubbish dump of the cell involved in the degradation of proteins and other cell compartments, mitochondria were considered solely involved in the oxidation of energy substrate to get ATP, together with other minor duties. Nowadays, our view of these organelles is profoundly changed since studies demonstrated that mitochondria and lysosome are mutually functional, maintaining proper cell homeostasis. Furthermore, the onset of neurodegenerative diseases (i.e., Parkinson's disease, Alzheimer's disease, lysosomal storage disorders, and amyotrophic lateral

Accumulation of DNA lesions causing transcription stress is associated with natural and accelerated aging and culminates with profound metabolic alterations. Our understanding of the mechanisms governing metabolic redesign upon genomic instability, however, is highly rudimentary. Using Ercc1-defective mice and Xpg knock-out mice, we demonstrate that combined defects in transcription-coupled DNA repair (TCR) and in nucleotide excision repair (NER) directly affect bioenergetics due to declined transcription, leading to increased ATP levels. This in turn inhibits glycolysis allosterically and favors glucose rerouting through the pentose phosphate shunt, eventually enhancing production of NADPH-reducing equivalents. In NER/TCR-defective mutants, augmented NADPH is not counterbalanced by increased production of pro-oxidants and thus pentose phosphate potentiation culminates in an over-reduced redox state. Skin fibroblasts from the TCR disease Cockayne syndrome confirm results in animal models. Overall, these findings unravel a mechanism connecting DNA damage and transcriptional stress to metabolic redesign and protective antioxidant defenses.

ADAM10 is the α-secretase that cleaves amyloid-β protein precursor in the non-amyloidogenic pathway in Alzheimer's disease (AD) and is known to be regulated by different microRNAs (miRNAs), which are post-transcriptional regulators related to several biological and pathological processes, including AD. Here we proposed to explore and validate miRNAs that have direct or indirect relations to the AD pathophysiology and ADAM10 gene. Approximately 700 miRNAs were analyzed and 21 differentially expressed miRNAs were validated in a sample of 21 AD subjects and 17 cognitively healthy matched controls. SH-SY5Y cells were transfected with miR-144-5p, miR-221, and miR-374 mimics and inhibitors, and ADAM10 protein levels were evaluated. miR-144-5p, miR-221, and miR-374 were downregulated in AD. The overexpression of miR-221 in SH-SY5Y cells resulted in ADAM10 reduction and its inhibition in ADAM10 increased. These findings show that miR-221 can be a new potential therapeutic target for increasing ADAM10 levels in AD. In addition, these results can contribute to the better understanding of ADAM10 post-transcriptional regulation.

Melanoma is an aggressive tumor with still poor therapy outcomes. δ-tocotrienol (δ-TT) is a vitamin E derivative displaying potent anti-cancer properties. Previously, we demonstrated that δ-TT triggers apoptosis in human melanoma cells. Here, we investigated whether it might also activate paraptosis, a non-canonical programmed cell death. In accordance with the main paraptotic features, δ-TT was shown to promote cytoplasmic vacuolization, associated with endoplasmic reticulum/mitochondrial dilation and protein synthesis, as well as MAPK activation in A375 and BLM cell lines. Moreover, treated cells exhibited a significant reduced expression of OXPHOS complex I and a marked decrease in oxygen consumption and mitochondrial membrane potential, culminating in decreased ATP synthesis and AMPK phosphorylation. This mitochondrial dysfunction resulted in ROS overproduction, found to be responsible for paraptosis induction. Additionally, δ-TT caused Ca2+ homeostasis disruption, with endoplasmic reticulum-derived ions accumulating in mitochondria and activating the paraptotic signaling. Interestingly, by using both IP3R and VDAC inhibitors, a close cause-effect relationship between mitochondrial Ca2+ overload and ROS generation was evidenced. Collectively, these results provide novel insights into δ-TT anti-melanoma activity, highlighting its ability to induce mitochondrial dysfunction-mediated paraptosis. Graphic Abstract δ-tocotrienol induces paraptotic cell death in human melanoma cells, causing endoplasmic reticulum dilation and mitochondrial swelling. These alterations induce an impairment of mitochondrial function, ROS production and calcium overload.