Obstructive sleep apnea syndrome, characterized by repetitive episodes of tissue hypoxia, is associated with several metabolic impairments. Role of fatty acids and lipids attracts attention in its pathogenesis for their metabolic effects. Parallelly, hypoxia-induced activation of reverse tricarboxylic acid cycle (rTCA) with reductive glutamine metabolism provides precursor molecules for de novo lipogenesis. Gas-permeable cultureware was used to culture L6-myotubes in chronic hypoxia (12%, 4% and 1% O2) with 13C labelled glutamine and inhibitors of glutamine uptake or rTCA-mediated lipogenesis. We investigated changes in lipidomic profile, 13C appearance in rTCA-related metabolites, gene and protein expression of rTCA-related proteins and glutamine transporters, glucose uptake and lactate production. Lipid content increased by 308% at 1% O2, predominantly composed of saturated fatty acids, while triacylglyceroles containing unsaturated fatty acids and membrane lipids (phosphatidylcholines, phosphatidylethanolamines, phosphatidylinositol) decreased by 20-70%. rTCA labelling of malate, citrate and 2-hydroxyglutarate increased by 4.7-fold, 2.2-fold and 1.9-fold in 1% O2, respectively. ATP-dependent citrate lyase inhibition in 1% O2 decreased lipid amount by 23% and increased intensity of triacylglyceroles containing unsaturated fatty acids by 56-80%. Lactate production increased with hypoxia. Glucose uptake dropped by 75% with progression of hypoxia from 4% to 1% O2. Protein expression remained unchanged. Altogether, hypoxia modified cell metabolism leading to lipid composition alteration and rTCA activation.

• Klíčová slova
• L6 myotubes, glutamin, hypoxia, lipids, obstructive sleep apnea, reverse TCA,
• MeSH
• citrátový cyklus * genetika   MeSH
• hypoxie metabolismus   MeSH
• kosterní svalová vlákna metabolismus   MeSH
• lidé MeSH
• mastné kyseliny * metabolismus   MeSH
• nenasycené mastné kyseliny metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• mastné kyseliny * MeSH
• nenasycené mastné kyseliny MeSH

Antidepressants, in particular tricyclic ones (TCA), and inhibitors of monoaminooxidase (IMAO) exert a number of undesirable cardiovascular effects. TCA and IMAO frequently cause postural hypotension (PH). IMAO administration is associated with the risk of hypertensive crisis. TCA raises the heart rate and can cause abnormalities in the conduction of the cardiac excitation. TCA are contraindicated after myocardial infarction and are the cause of death after overdosage. When PH is undesirable, in hypertension and cardiac insufficiency the following safe antidepressants are recommended: nortriptyline, mianserine, trazodone and viloxazine. In abnormalities of conduction of the cardiac excitation and after myocardial infarction only mianserine, trazodione and viloxazine are recommended. With regard to cardiovascular toxicity, antidepressants from the series of selective inhibitors of serotonin reabsorption are very promising: fluvoxamine, fluoxetine, citalopram, paroxetine and sertraline. The same applies also to the reversible IMAO type A moclobemide.

• MeSH
• antidepresiva škodlivé účinky   MeSH
• hemodynamika účinky léků   MeSH
• kardiovaskulární nemoci chemicky indukované   patofyziologie   MeSH
• lidé MeSH
• srdeční frekvence účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• anglický abstrakt MeSH
• časopisecké články MeSH
• Názvy látek
• antidepresiva MeSH

A commercially available porous silica rod column was used as a separation tool for the sequential injection analysis (SIA). A porous solid monolithic column showed high performance at a low pressure, allowing sequential injection analysis to be used for the first time for separation in HPLC fashion. In this contribution, we tried to demonstrate a new separation concept with SIA manifold for the simultaneous determination of four different compounds (methylparaben (MP), propylparaben (PP), triamcinolone acetonide (TCA) and internal standard ketoprofen (KP)) in a pharmaceutical triamcinolon cream 0.1% formulation. A Chromolith Flash RP-18e, 25 mm x 4.6 mm column with a 10 mm pre-column (Merck, Germany) and a FIAlab 3000 system (USA) with an 8-port selection valve and 10 ml syringe were used for sequential injection chromatographic separations in our study. The mobile phase used was acetonitrile-methanol-water (35:5:65, v/v/v) + 0.05% nonylamine, pH 2.5, flow rate 0.6 ml min(-1). The analysis time was <6 min. A novel sequential injection chromatography (SIC) technique with UV spectrophotometric detection was optimised and validated.

• MeSH
• oxid křemičitý chemie   MeSH
• spektrofotometrie ultrafialová MeSH
• vysokoúčinná kapalinová chromatografie metody   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• oxid křemičitý MeSH

Metabolic dysfunction mutations can impair energy sensing and cause cancer. Loss of function of the mitochondrial tricarboxylic acid (TCA) cycle enzyme subunit succinate dehydrogenase B (SDHB) results in various forms of cancer typified by pheochromocytoma (PC). Here we delineate a signaling cascade where the loss of SDHB induces the Warburg effect, triggers dysregulation of [Ca2+]i, and aberrantly activates calpain and protein kinase Cdk5, through conversion of its cofactor from p35 to p25. Consequently, aberrant Cdk5 initiates a phospho-signaling cascade where GSK3 inhibition inactivates energy sensing by AMP kinase through dephosphorylation of the AMP kinase γ subunit, PRKAG2. Overexpression of p25-GFP in mouse adrenal chromaffin cells also elicits this phosphorylation signaling and causes PC. A potent Cdk5 inhibitor, MRT3-007, reverses this phospho-cascade, invoking a senescence-like phenotype. This therapeutic approach halted tumor progression in vivo. Thus, we reveal an important mechanistic feature of metabolic sensing and demonstrate that its dysregulation underlies tumor progression in PC and likely other cancers.

• Klíčová slova
• AMPK, CP: Cancer, CP: Metabolism, Cdk5, PRKAG2, SDHB, Warburg effect, cancer bioenergetics, neuroendocrine tumor, p53, pheochromocytoma, senescence,
• MeSH
• adenylátkinasa * metabolismus   MeSH
• cyklin-dependentní kinasa 5 metabolismus   MeSH
• energetický metabolismus MeSH
• fosforylace MeSH
• kinasa 3 glykogensynthasy metabolismus   MeSH
• myši MeSH
• neuroendokrinní karcinom * MeSH
• sukcináty MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, N.I.H., Intramural MeSH
• Názvy látek
• adenylátkinasa * MeSH
• cyklin-dependentní kinasa 5 MeSH
• kinasa 3 glykogensynthasy MeSH
• sukcináty MeSH

OBJECTIVE: Redox signaling mediated by reversible oxidative cysteine thiol modifications is crucial for driving cellular adaptation to dynamic environmental changes, maintaining homeostasis, and ensuring proper function. This is particularly critical in pancreatic β-cells, which are highly metabolically active and play a specialized role in whole organism glucose homeostasis. Glucose stimulation in β-cells triggers signals leading to insulin secretion, including changes in ATP/ADP ratio and intracellular calcium levels. Additionally, lipid metabolism and reactive oxygen species (ROS) signaling are essential for β-cell function and health. METHODS: We employed IodoTMT isobaric labeling combined with tandem mass spectrometry to elucidate redox signaling pathways in pancreatic β-cells. RESULTS: Glucose stimulation significantly increases ROS levels in β-cells, leading to targeted reversible oxidation of proteins involved in key metabolic pathways such as glycolysis, the tricarboxylic acid (TCA) cycle, pyruvate metabolism, oxidative phosphorylation, protein processing in the endoplasmic reticulum (ER), and insulin secretion. Furthermore, the glucose-induced increase in reversible cysteine oxidation correlates with the presence of other post-translational modifications, including acetylation and phosphorylation. CONCLUSIONS: Proper functioning of pancreatic β-cell metabolism relies on fine-tuned regulation, achieved through a sophisticated system of diverse post-translational modifications that modulate protein functions. Our findings demonstrate that glucose induces the production of ROS in pancreatic β-cells, leading to targeted reversible oxidative modifications of proteins. Furthermore, protein activity is modulated by acetylation and phosphorylation, highlighting the complexity of the regulatory mechanisms in β-cell function.

• Klíčová slova
• Glucose, Pancreatic β-cells, Posttranslational modifications, ROS, Redox proteomics, Redox signaling,
• MeSH
• beta-buňky * metabolismus   účinky léků   MeSH
• fyziologická adaptace fyziologie   MeSH
• glukosa * metabolismus   MeSH
• lidé MeSH
• myši MeSH
• oxidace-redukce * MeSH
• posttranslační úpravy proteinů MeSH
• reaktivní formy kyslíku * metabolismus   MeSH
• sekrece inzulinu účinky léků   fyziologie   MeSH
• signální transdukce * fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukosa * MeSH
• reaktivní formy kyslíku * MeSH