Mitochondria extrude protons across their inner membrane to generate the mitochondrial potential (ΔΨm) and pH gradient (ΔpHm) that both power ATP synthesis. Mitochondrial uptake efflux of many ions metabolites are driven exclusively by ΔpHm, whose in situ regulation is poorly characterized. Here, we report first dynamic measurements ΔpHm living cells, using a mitochondrially targeted, pH-sensitive YFP (SypHer) combined with cytosolic indicator (5-(and 6)-carboxy-SNARF-1). The resting matrix...

Barrier integrity is central to the maintenance of healthy immunological homeostasis. Impaired skin barrier function linked with enhanced allergen sensitization and development diseases such as atopic dermatitis (AD), which can precede other allergic disorders, for example, food allergies asthma. Epidemiological evidence indicates that children suffering from have lower levels dietary fibre-derived short-chain fatty acids (SCFA). Using an experimental model AD-like inflammation, we report a...

Medium-chain triglycerides have been used as part of a ketogenic diet effective in reducing epileptic episodes. The health benefits the derived medium-chain fatty acids (MCFAs) are thought to result from stimulation liver ketogenesis providing fuel for brain. We tested whether MCFAs direct effects on energy metabolism induced pluripotent stem cell-derived human astrocytes and neurons. Using single-cell imaging, we observed an acute pronounced reduction mitochondrial electrical potential...

Mitochondria capture and subsequently release Ca(2+) ions, thereby sensing shaping cellular signals. The uniporter MCU mediates uptake, whereas NCLX (mitochondrial Na/Ca exchanger) LETM1 (leucine zipper-EF-hand-containing transmembrane protein 1) were proposed to exchange against Na(+) or H(+), respectively. Here we study the role of these ion exchangers in mitochondrial extrusion Ca(2+)-metabolic coupling. Both proteins expressed HeLa cells mitochondria. rate efflux, measured with a...

During cell activation, mitochondria play an important role in Ca2+ homoeostasis due to the presence of a fast and specific channel its inner membrane, mitochondrial uniporter. This allows buffer local cytosolic [Ca2+] changes controls intramitochondrial levels, thus modulating variety phenomena from respiratory rate apoptosis. We have described recently that SB202190, inhibitor p38 MAPK (mitogen-activated protein kinase), strongly activated show present study series natural plant...

The thiourea derivative KB-R7943, originally developed as inhibitor of the plasma membrane Na(+)/Ca(2+) exchanger, has been shown to protect against myocardial ischemia-reperfusion injury. We have studied here its effects on mitochondrial Ca(2+) fluxes.[Ca(2+)] in cytosol, mitochondria and endoplasmic reticulum (ER), potential were monitored using both luminescent (targeted aequorins) fluorescent (fura-2, tetramethylrhodamine ethyl ester) probes HeLa cells.KB-R7943 was also a potent...

Background and Purpose Quinic acid (QA) is an abundant natural compound from plant sources which may improve metabolic health. However, little attention has been paid to its effects on pancreatic beta‐cell functions, contribute the control of health by lowering blood glucose. Strategies targeting signal transduction are a new approach for diabetes treatment. This study investigated efficacy QA stimulate function basic molecular machinery metabolism–secretion coupling. Experimental Approach...

Abstract A robust and reproducible method for culturing monolayers of adherent well-spread primary islet cells on glass coverslips is required detailed imaging studies by super-resolution live-cell microscopy. Guided an observation that dispersed spread adhere well surfaces in neuronal co-culture form a monolayer connected cells, we demonstrate the absence neurons, well-defined surface coatings combined with components culture media collectively support attachment growth human or rat as...

We have previously shown that the compound CGP37157, a mitochondrial Na+/Ca2+ exchanger inhibitor, increases lifespan and improves muscle structure during aging in wild-type C. elegans nematodes. used here rotenone model of Parkinson’s disease to test ability CGP37157 rescue alterations induced by toxicant. Rotenone, respiratory chain complex I reduced worm activity, measured as mobility, pharyngeal pumping, defecation rate. It also increased ROS production, decreased membrane potential,...

Pancreatic β-cells secrete insulin to lower blood glucose, following a meal. Maintenance of β-cell function is essential preventing type 2 diabetes. In pancreatic β-cells, mitochondrial matrix calcium an activating signal for secretion. Recently, the molecular identity uniporter (MCU), transporter that mediates uptake, was revealed. Its role in transduction modulation clarified, opening new perspectives intervention. Here, we investigated effects Ca2+-targeted nutritional intervention...

Abstract The secretory granules constitute one of the less well‐known compartments in terms Ca 2+ dynamics. They contain large amounts total , but free intragranular [Ca ] ([Ca SG ), mechanisms for uptake and release from their physiological significance regarding exocytosis are still matters debate. We used present work an aequorin chimera targeted to investigate homeostasis bovine adrenal chromaffin cells. found that most intracellular is a compartment with 50–100 μ m . accumulation into...

Abstract Aims/hypothesis In islets from individuals with type 2 diabetes and in exposed to chronic elevated glucose, mitochondrial energy metabolism is impaired. Here, we studied early metabolic changes adaptations human beta cells during glucose stress. Methods Respiration cytosolic ATP were measured islet cell clusters after culture for 4 days 11.1 mmol/l glucose. Metabolomics was applied analyse intracellular metabolite as a result of stress conditions. Alterations function followed using...

Mitochondrial dysfunction induces a strong adaptive retrograde signaling response; however, many of the downstream effectors this response remain to be discovered. Here, we studied shared transcriptional responses three different mitochondrial respiratory chain inhibitors in human primary skin fibroblasts using QuantSeq 3'-RNA-sequencing. We found that genes involved mevalonate pathway were concurrently downregulated, irrespective complex affected. Targeted metabolomics demonstrated impaired...

Ca(2+) uptake by mitochondria is a key element in the control of cellular homeostasis and Ca(2+)-dependent phenomena. It has been known for many years that this mediated mitochondrial uniporter, specific channel inner membrane. We have shown previously strongly activated series natural phytoestrogenic flavonoids. show here several agonists antagonists estrogen receptors (ERs) also modulate activity uniporter. The alpha-ER agonist 4,4',4''-(4-propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol (PPT)...

The recent availability of activators the mitochondrial Ca 2+ uniporter allows direct testing influence uptake on overall homeostasis cell. We show here that activation by 4,4′,4″‐(4‐propyl‐[1H]‐pyrazole‐1,3,5‐triyl)trisphenol (PPT) or kaempferol stimulates histamine‐induced release from endoplasmic reticulum (ER) and this effect is enhanced if Na + –Ca exchanger simultaneously inhibited with CGP37157. This suggests both mitochondria control ability local microdomains to produce feedback...

Article7 February 2017Open Access Transparent process L-OPA1 regulates mitoflash biogenesis independently from membrane fusion Manon Rosselin Department of Cell Physiology and Metabolism, University Geneva, Switzerland Search for more papers by this author Jaime Santo-Domingo Nestlé Institute Health Sciences SA, EPFL Innovation Park, Lausanne, Flavien Bermont Marta Giacomello Biology, Padova, Italy Nicolas Demaurex Corresponding Author [email protected] orcid.org/0000-0002-9933-6772...

In pancreatic β-cells, mitochondria generate signals that promote insulin granule exocytosis. Here we study how lysine acetylation of mitochondrial proteins mechanistically affects metabolism-secretion coupling in insulin-secreting cells. Using mass spectrometry-based proteomics, identified sites rat insulinoma cell line clone 1E cells lacking the deacetylase sirtuin-3 (SIRT3), several matrix are hyperacetylated. Disruption SIRT3 gene has a deleterious effect on energy metabolism and Ca2+...

Regulation of mitochondrial redox balance is emerging as a key event for cell signaling in both physiological and pathological conditions. However, the link between state modulation these conditions remains poorly defined. Here, we discovered that activation evolutionary conserved calcium uniporter (MCU) modulates state. By using mitochondria-targeted sensors genetic MCU-ablated models, provide evidence causality MCU net reduction (but not cytosolic) Redox redox-sensitive groups via...

Securin and separase play a key role in sister chromatid separation during anaphase. However, growing body of evidence suggests that addition to regulating chromosome segregation, securin display functions implicated membrane traffic Caenorhabditis elegans Drosophila. Here we show mammalian cells both associate with membranes depletion either protein causes robust swelling the trans-Golgi network (TGN) along appearance large endocytic vesicles perinuclear region. These changes are...