The mitochondriotropic antioxidants AntiOxBEN and AntiOxCIN are structurally-similar but differentially alter energy homeostasis in human skin fibroblasts.

Mitochondrial dysfunction and increased reactive oxygen species (ROS) generation play an import role in different human pathologies. In this context, mitochondrial targeting of potentially protective antioxidants by their coupling to the lipophilic triphenylphosphonium cation (TPP) is widely applied. Employing a six‑carbon (C) linker, we recently demonstrated that mitochondria-targeted phenolic antioxidants derived from gallic acid (AntiOxBEN) and caffeic acid (AntiOxCIN) counterbalance oxidative stress in primary human skin fibroblasts by activating ROS-protective mechanisms.

The Hypoxia Response Pathway: A Potential Intervention Target in Parkinson's Disease?

Parkinson's disease (PD) is a progressive neurodegenerative disorder for which only symptomatic treatments are available. Both preclinical and clinical studies suggest that moderate hypoxia induces evolutionarily conserved adaptive mechanisms that enhance neuronal viability and survival. Therefore, targeting the hypoxia response pathway might provide neuroprotection by ameliorating the deleterious effects of mitochondrial dysfunction and oxidative stress, which underlie neurodegeneration in PD.

Performance of TMRM and Mitotrackers in mitochondrial morphofunctional analysis of primary human skin fibroblasts.

Mitochondrial membrane potential (Δψ) and morphology are considered key readouts of mitochondrial functional state. This morphofunction can be studied using fluorescent dyes ("probes") like tetramethylrhodamine methyl ester (TMRM) and Mitotrackers (MTs). Although these dyes are broadly used, information comparing their performance in mitochondrial morphology quantification and Δψ-sensitivity in the same cell model is still scarce.

SMDT1 variants impair EMRE-mediated mitochondrial calcium uptake in patients with muscle involvement.

Ionic calcium (Ca) is a key messenger in signal transduction and its mitochondrial uptake plays an important role in cell physiology. This uptake is mediated by the mitochondrial Ca uniporter (MCU), which is regulated by EMRE (essential MCU regulator) encoded by the SMDT1 (single-pass membrane protein with aspartate rich tail 1) gene. This work presents the genetic, clinical and cellular characterization of two patients harbouring SMDT1 variants and presenting with muscle problems.

Dimethyl itaconate induces long-term innate immune responses and confers protection against infection.

Itaconate is an immunomodulatory metabolite produced by immune cells under microbial stimulation and certain pro-inflammatory conditions and triggers antioxidant and anti-inflammatory responses. We show that dimethyl itaconate, a derivative of itaconate previously linked to suppression of inflammation and widely employed as an alternative to the endogenous metabolite, can induce long-term transcriptional, epigenomic, and metabolic changes, characteristic of trained immunity. Dimethyl itaconate alters glycolytic and mitochondrial energetic metabolism, ultimately leading to increased responsiveness to microbial ligand stimulation.

In Vitro Skeletal Muscle Model of PGM1 Deficiency Reveals Altered Energy Homeostasis.

Phosphoglucomutase 1 (PGM1) is a key enzyme for the regulation of energy metabolism from glycogen and glycolysis, as it catalyzes the interconversion of glucose 1-phosphate and glucose 6-phosphate. PGM1 deficiency is an autosomal recessive disorder characterized by a highly heterogenous clinical spectrum, including hypoglycemia, cleft palate, liver dysfunction, growth delay, exercise intolerance, and dilated cardiomyopathy. Abnormal protein glycosylation has been observed in this disease.

Metabolic impact of genetic and chemical ADP/ATP carrier inhibition in renal proximal tubule epithelial cells.

Mitochondrial dysfunction is pivotal in drug-induced acute kidney injury (AKI), but the underlying mechanisms remain largely unknown. Transport proteins embedded in the mitochondrial inner membrane form a significant class of potential drug off-targets. So far, most transporter-drug interactions have been reported for the mitochondrial ADP/ATP carrier (AAC).

Stress-dependent macromolecular crowding in the mitochondrial matrix.

Macromolecules of various sizes induce crowding of the cellular environment. This crowding impacts on biochemical reactions by increasing solvent viscosity, decreasing the water-accessible volume and altering protein shape, function, and interactions. Although mitochondria represent highly protein-rich organelles, most of these proteins are somehow immobilized.

The DEAD-box RNA helicase Dhx15 controls glycolysis and arbovirus replication in Aedes aegypti mosquito cells.

Aedes aegypti mosquitoes are responsible for the transmission of arthropod-borne (arbo)viruses including dengue and chikungunya virus (CHIKV) but in contrast to human hosts, arbovirus-infected mosquitoes are able to efficiently control virus replication to sub-pathological levels. Yet, our knowledge of the molecular interactions of arboviruses with their mosquito hosts is incomplete. Here, we aimed to identify and characterize novel host genes that control arbovirus replication in Aedes mosquitoes.

The decylTPP mitochondria-targeting moiety lowers electron transport chain supercomplex levels in primary human skin fibroblasts.

Attachment of cargo molecules to lipophilic triphenylphosphonium (TPP) cations is a widely applied strategy for mitochondrial targeting. We previously demonstrated that the vitamin E-derived antioxidant Trolox increases the levels of active mitochondrial complex I (CI), the first complex of the electron transport chain (ETC), in primary human skin fibroblasts (PHSFs) of Leigh Syndrome (LS) patients with isolated CI deficiency. Primed by this finding, we here studied the cellular effects of mitochondria-targeted Trolox (MitoE10), mitochondria-targeted ubiquinone (MitoQ10) and their mitochondria-targeting moiety decylTPP (C-TPP).

Mechanisms and mathematical modeling of ROS production by the mitochondrial electron transport chain.

Reactive oxygen species (ROS) are recognized both as damaging molecules and intracellular signaling entities. In addition to its role in ATP generation, the mitochondrial electron transport chain (ETC) constitutes a relevant source of mitochondrial ROS, in particular during pathological conditions. Mitochondrial ROS homeostasis depends on species- and site-dependent ROS production, their bioreactivity, diffusion, and scavenging.

Ndufs4 knockout mouse models of Leigh syndrome: pathophysiology and intervention.

Mitochondria are small cellular constituents that generate cellular energy (ATP) by oxidative phosphorylation (OXPHOS). Dysfunction of these organelles is linked to a heterogeneous group of multisystemic disorders, including diabetes, cancer, ageing-related pathologies and rare mitochondrial diseases. With respect to the latter, mutations in subunit-encoding genes and assembly factors of the first OXPHOS complex (complex I) induce isolated complex I deficiency and Leigh syndrome.

The ketogenic diet as a therapeutic intervention strategy in mitochondrial disease.

Classical mitochondrial disease (MD) represents a group of complex metabolic syndromes primarily linked to dysfunction of the mitochondrial ATP-generating oxidative phosphorylation (OXPHOS) system. To date, effective therapies for these diseases are lacking. Here we discuss the ketogenic diet (KD), being a high-fat, moderate protein, and low carbohydrate diet, as a potential intervention strategy.

oxLDL-Induced Trained Immunity Is Dependent on Mitochondrial Metabolic Reprogramming.

Following brief exposure to endogenous atherogenic particles, such as oxidized low-density lipoprotein (oxLDL), monocytes/macrophages can adopt a long-term pro-inflammatory phenotype, which is called trained immunity. This mechanism might contribute to the chronic low-grade inflammation that characterizes atherosclerosis. In this study, we aim to elucidate immunometabolic pathways that drive oxLDL-induced trained immunity.

Live-Cell Assessment of Reactive Oxygen Species Levels Using Dihydroethidine.

Reactive oxygen species (ROS) play an important role in cellular (patho)physiology. Empirical evidence suggests that mitochondria are an important source of ROS, especially under pathological conditions. Here, we describe a method for ROS measurement using dihydroethidium (HEt) and live-cell microscopy.

Mitochondria-targeted phenolic antioxidants induce ROS-protective pathways in primary human skin fibroblasts.

Phytochemical antioxidants like gallic and caffeic acid are constituents of the normal human diet that display beneficial health effects, potentially via activating stress response pathways. Using primary human skin fibroblasts (PHSFs) as a model, we here investigated whether such pathways were induced by novel mitochondria-targeted variants of gallic acid (AntiOxBEN) and caffeic acid (AntiOxCIN). Both molecules reduced cell viability with similar kinetics and potency (72 h incubation, IC50 ~23 μM).

Energy expenditure during cell spreading influences the cellular response to matrix stiffness.

Cells respond to the mechanical properties of the extracellular matrix (ECM) through formation of focal adhesions (FAs), re-organization of the actin cytoskeleton and adjustment of cell contractility. These are energy-demanding processes, but a potential causality between mechanical cues (matrix stiffness) and cellular (energy) metabolism remains largely unexplored. Here, we cultured human mesenchymal stem cells (hMSCs) on stiff (20 kPa) or soft (1 kPa) substrate and demonstrate that cytoskeletal reorganization and FA formation spreading on stiff substrates lead to a drop in intracellular ATP levels, correlating with activation of AMP-activated protein kinase (AMPK).