While bioorthogonal reactions are routinely employed in living cells and organisms, their application within individual organelles remains limited. In this review, we highlight diverse examples of bioorthogonal reactions used to investigate the roles of biomolecules and biological processes as well as advanced imaging techniques within cellular organelles. These innovations hold great promise for therapeutic interventions in personalized medicine and precision therapies. We also address existing challenges related to the selectivity and trafficking of subcellular dynamics. Organelle-targeted bioorthogonal reactions have the potential to significantly advance our understanding of cellular organization and function, provide new pathways for basic research and clinical applications, and shape the direction of cell biology and medical research.

• Klíčová slova
• Bioconjugations, Bioorthogonal reactions, Cellular organelles, Click chemistry, Targeting,
• MeSH
• biologie buňky MeSH
• organely * chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Mitochondrially targeted anticancer drugs (mitocans) that disrupt the energy-producing systems of cancer are emerging as new potential therapeutics. Mitochondrially targeted tamoxifen (MitoTam), an inhibitor of mitochondrial respiration respiratory complex I, is a first-in-class mitocan that was tested in the phase I/Ib MitoTam-01 trial of patients with metastatic cancer. MitoTam exhibited a manageable safety profile and efficacy; among 37% (14/38) of responders, the efficacy was greatest in patients with metastatic renal cell carcinoma (RCC) with a clinical benefit rate of 83% (5/6) of patients. This can be explained by the preferential accumulation of MitoTam in the kidney tissue in preclinical studies. Here we report the mechanism of action and safety profile of MitoTam in a case series of RCC patients. All six patients were males with a median age of 69 years, who had previously received at least three lines of palliative systemic therapy and suffered progressive disease before starting MitoTam. We recorded stable disease in four, partial response in one, and progressive disease (PD) in one patient. The histological subtype matched clear cell RCC (ccRCC) in the five responders and claro-cellular carcinoma with sarcomatoid features in the non-responder. The number of circulating tumor cells (CTCs) was evaluated longitudinally to monitor disease dynamics. Beside the decreased number of CTCs after MitoTam administration, we observed a significant decrease of the mitochondrial network mass in enriched CTCs. Two patients had long-term clinical responses to MitoTam, of 50 and 36 weeks. Both patients discontinued treatment due to adverse events, not PD. Two patients who completed the trial in November 2019 and May 2020 are still alive without subsequent anticancer therapy. The toxicity of MitoTam increased with the dosage but was manageable. The efficacy of MitoTam in pretreated ccRCC patients is linked to the novel mechanism of action of this first-in-class mitochondrially targeted drug.

• Klíčová slova
• MitoTam, case series, efficacy, mechanism of action, mitocans, mitochondria, mitochondrially targeted tamoxifen, phase I/Ib trial, renal cell carcinoma, safety,
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

• MeSH
• imunoterapie * MeSH
• lidé MeSH
• nádory ledvin * farmakoterapie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• dopisy MeSH
• práce podpořená grantem MeSH

The increased production of reactive oxygen species and oxidative stress are important factors contributing to the development of diseases of the cardiovascular and central nervous systems. Molecular hydrogen is recognized as an emerging therapeutic, and its positive effects in the treatment of pathologies have been documented in both experimental and clinical studies. The therapeutic potential of hydrogen is attributed to several major molecular mechanisms. This review focuses on the effects of hydrogen on the cardiovascular and central nervous systems, and summarizes current knowledge about its actions, including the regulation of redox and intracellular signaling, alterations in gene expressions, and modulation of cellular responses (e.g., autophagy, apoptosis, and tissue remodeling). We summarize the functions of hydrogen as a regulator of nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated redox signaling and the association of hydrogen with mitochondria as an important target of its therapeutic action. The antioxidant functions of hydrogen are closely associated with protein kinase signaling pathways, and we discuss possible roles of the phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) and Wnt/β-catenin pathways, which are mediated through glycogen synthase kinase 3β and its involvement in the regulation of cellular apoptosis. Additionally, current knowledge about the role of molecular hydrogen in the modulation of autophagy and matrix metalloproteinases-mediated tissue remodeling, which are other responses to cellular stress, is summarized in this review.

• Klíčová slova
• autophagy, matrix metalloproteinases, molecular hydrogen, oxidative stress,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Values of the calcium retention capacity (CRC) of rat liver mitochondria are highly dependent on the experimental conditions used. When increasing amounts of added calcium chloride are used (1.25-10 nmol), the values of the CRC increase 3-fold. When calcium is added in 75 s intervals, the CRC values increase by 30 % compared with 150 s interval additions. CRC values are not dependent on the calcium/protein ratio in the measured sample in our experimental design. We also show that a more detailed evaluation of the fluorescence curves can provide new information about mitochondrial permeability transition pore opening after calcium is added.

• MeSH
• biologický transport MeSH
• jaterní mitochondrie metabolismus   MeSH
• játra metabolismus   MeSH
• krysa rodu Rattus MeSH
• mitochondriální membrány metabolismus   MeSH
• permeabilita MeSH
• přechodový pór mitochondriální permeability metabolismus   MeSH
• transportní proteiny mitochondriální membrány metabolismus   MeSH
• vápník metabolismus   MeSH
• výzkumný projekt MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• Názvy látek
• přechodový pór mitochondriální permeability MeSH
• transportní proteiny mitochondriální membrány MeSH
• vápník MeSH

We synthesized a mitochondria-targeted honokiol (Mito-HNK) that facilitates its mitochondrial accumulation; this dramatically increases its potency and efficacy against highly metastatic lung cancer lines in vitro, and in orthotopic lung tumor xenografts and brain metastases in vivo. Mito-HNK is >100-fold more potent than HNK in inhibiting cell proliferation, inhibiting mitochondrial complex ?, stimulating reactive oxygen species generation, oxidizing mitochondrial peroxiredoxin-3, and suppressing the phosphorylation of mitoSTAT3. Within lung cancer brain metastases in mice, Mito-HNK induced the mediators of cell death and decreased the pathways that support invasion and proliferation. In contrast, in the non-malignant stroma, Mito-HNK suppressed pathways that support metastatic lesions, including those involved in inflammation and angiogenesis. Mito-HNK showed no toxicity and targets the metabolic vulnerabilities of primary and metastatic lung cancers. Its pronounced anti-invasive and anti-metastatic effects in the brain are particularly intriguing given the paucity of treatment options for such patients either alone or in combination with standard chemotherapeutics.

• Klíčová slova
• Immunology, Medicinal and Aromatic Plants, Natural Product Chemistry,
• Publikační typ
• časopisecké články MeSH

Methyltriphenylphosphonium (TPMP) salts have been widely used to measure the mitochondrial membrane potential and the triphenylphosphonium (TPP+) moiety has been attached to many bioactive compounds including antioxidants to target them into mitochondria thanks to their high affinity to accumulate in the mitochondrial matrix. The adverse effects of these compounds on cellular metabolism have been insufficiently studied and are still poorly understood. Micromolar concentrations of TPMP cause a progressive inhibition of cellular respiration in adherent cells without a marked effect on mitochondrial coupling. In permeabilized cells the inhibition was limited to NADH-linked respiration. We found a mixed inhibition of the Krebs cycle enzyme 2-oxoglutarate dehydrogenase complex (OGDHC) with an estimated IC50 3.93 [3.70-4.17] mM, which is pharmacologically plausible since it corresponds to micromolar extracellular concentrations. Increasing the lipophilic character of the used TPP+ compound further potentiates the inhibition of OGDHC activity. This effect of TPMP on the Krebs cycle ought to be taken into account when interpreting observations on cells and mitochondria in the presence of TPP+ derivatives. Compounds based on or similar to TPP+ derivatives may also be used to alter OGDHC activity for experimental or therapeutic purposes.

• MeSH
• buněčné linie MeSH
• citrátový cyklus účinky léků   MeSH
• citrátsynthasa účinky léků   metabolismus   MeSH
• glutamátdehydrogenasa účinky léků   metabolismus   MeSH
• isocitrátdehydrogenasa účinky léků   metabolismus   MeSH
• ketoglutarátdehydrogenasový komplex antagonisté a inhibitory   metabolismus   MeSH
• kosterní svaly enzymologie   MeSH
• krysa rodu Rattus MeSH
• malátdehydrogenasa účinky léků   metabolismus   MeSH
• membránový potenciál mitochondrií účinky léků   MeSH
• oniové sloučeniny farmakologie   MeSH
• potkani Wistar MeSH
• pyruvátdehydrogenasový komplex účinky léků   metabolismus   MeSH
• svalové mitochondrie účinky léků   enzymologie   MeSH
• tritylové sloučeniny farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• citrátsynthasa MeSH
• glutamátdehydrogenasa MeSH
• isocitrátdehydrogenasa MeSH
• ketoglutarátdehydrogenasový komplex MeSH
• malátdehydrogenasa MeSH
• oniové sloučeniny MeSH
• pyruvátdehydrogenasový komplex MeSH
• triphenylmethylphosphonium MeSH Prohlížeč
• tritylové sloučeniny MeSH

Mitochondrial oxidative damage contributes to a wide range of pathologies. One therapeutic strategy to treat these disorders is targeting antioxidants to mitochondria by conjugation to the lipophilic triphenylphosphonium (TPP) cation. To date only hydrophobic antioxidants have been targeted to mitochondria; however, extending this approach to hydrophilic antioxidants offers new therapeutic and research opportunities. Here we report the development and characterization of MitoC, a mitochondria-targeted version of the hydrophilic antioxidant ascorbate. We show that MitoC can be taken up by mitochondria, despite the polarity and acidity of ascorbate, by using a sufficiently hydrophobic link to the TPP moiety. MitoC reacts with a range of reactive species, and within mitochondria is rapidly recycled back to the active ascorbate moiety by the glutathione and thioredoxin systems. Because of this accumulation and recycling MitoC is an effective antioxidant against mitochondrial lipid peroxidation and also decreases aconitase inactivation by superoxide. These findings show that the incorporation of TPP function can be used to target polar and acidic compounds to mitochondria, opening up the delivery of a wide range of bioactive compounds. Furthermore, MitoC has therapeutic potential as a new mitochondria-targeted antioxidant, and is a useful tool to explore the role(s) of ascorbate within mitochondria.

• Klíčová slova
• Ascorbic acid, Lipid peroxidation, Lipophilic cation, MitoC, MitoPerox, Mitochondria, Mitochondrial targeting,
• MeSH
• antioxidancia chemie   farmakologie   MeSH
• jaterní mitochondrie účinky léků   metabolismus   MeSH
• krysa rodu Rattus MeSH
• kyselina askorbová chemie   farmakologie   MeSH
• lékové transportní systémy metody   MeSH
• oxidace-redukce MeSH
• oxidační stres účinky léků   MeSH
• potkani Wistar MeSH
• vysokoúčinná kapalinová chromatografie MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antioxidancia MeSH
• kyselina askorbová MeSH