Undecanesulfonate is transported by uncoupling protein-1. Its inability to induce H+ uniport with reconstituted uncoupling protein-1 supports fatty acid cycling hypothesis. Rial et al. [Rial, E., Aguirregoitia, E., Jimenez-Jimenez, J., & Ledesma, A. (2004). Alkylsulfonates activate the uncoupling protein UCP1: Implications for the transport mechanism. Biochimica et Biophysica Acta, 1608, 122-130], have challenged the fatty acid cycling by observing uncoupling of brown adipose tissue mitochondria due to undecanesulfonate, interpreted as allosteric activation of uncoupling protein-1. We have estimated undecanesulfonate effects after elimination of endogenous fatty acids by carnitine cycle in the presence or absence of bovine serum albumin. We show that the undecanesulfonate effect is partly due to fatty acid release from albumin when undecanesulfonate releases bound fatty acid and partly represents a non-specific uncoupling protein-independent acceleration of respiration, since it proceeds also in rat heart mitochondria lacking uncoupling protein-1 and membrane potential is not decreased upon addition of undecanesulfonate without albumin. When the net fatty acid-induced uncoupling was assayed, the addition of undecanesulfonate even slightly inhibited the uncoupled respiration. We conclude that undecanesulfonate does not allosterically activate uncoupling protein-1 and that fatty acid cycling cannot be excluded on a basis of its non-specific effects.

• MeSH
• alkylsulfonany farmakologie   metabolismus   MeSH
• biologické modely MeSH
• biologický transport účinky léků   MeSH
• hnědá tuková tkáň metabolismus   účinky léků   MeSH
• iontové kanály MeSH
• iontový transport účinky léků   MeSH
• křečci praví MeSH
• krysa rodu rattus MeSH
• mastné kyseliny metabolismus   MeSH
• membránové potenciály účinky léků   MeSH
• membránové proteiny metabolismus   MeSH
• mitochondriální membrány fyziologie   účinky léků   MeSH
• mitochondriální proteiny MeSH
• mitochondrie metabolismus   účinky léků   MeSH
• protony MeSH
• sérový albumin hovězí farmakologie   MeSH
• spotřeba kyslíku účinky léků   MeSH
• srdeční mitochondrie metabolismus   účinky léků   MeSH
• transportní proteiny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH

Octahedral molybdenum cluster complexes have recently come forth as pertinent singlet oxygen photosensitizers towards biological applications. Still, their phototoxic efficiency in the absence of nanocarriers remains limited due to their poor cellular uptake. Here, two cationic octahedral molybdenum cluster complexes, bearing carboxylate ligands with triphenylphosphonium (1) or N-methyl pyridinium (2) mitochondria-targeting terminal functions, have been designed and synthesized. Their photophysical properties in water and in vitro biological activity were investigated in the context of blue-light photodynamic therapy of cancer and photoinactivation of bacteria. Upon blue light irradiation, complex 1 displays red luminescence with a quantum yield of 0.24 in water, whereas complex 2 is much less emissive (ΦL < 0.01). Nevertheless, both complexes efficiently produce singlet oxygen, O2(1Δg). Complex 1 is rapidly internalized into HeLa cells and accumulated in mitochondria, followed by relocation to lysosomes and clearance at longer times. In contrast, the more hydrophilic 2 is not internalized into HeLa cells, highlighting the effect of the apical ligands on the uptake properties. The treatment with 1 results in an intensive phototoxic effect under 460 nm irradiation (IC50 = 0.10 ± 0.02 μM), which exceeds by far those previously reported for octahedral cluster-based molecular photosensitizers. The ratio between phototoxicity and dark toxicity is approximately 50 and evidences a therapeutic window for the application of 1 in blue-light photodynamic therapy. Complex 1 also enters and efficiently photoinactivates Gram-positive bacteria Enterococcus faecalis and Staphylococcus aureus, documenting its suitability as a blue-light photosensitizer for antimicrobial applications.

• MeSH
• antibakteriální látky chemická syntéza   chemie   farmakologie   MeSH
• antitumorózní látky chemická syntéza   chemie   farmakologie   MeSH
• fotochemoterapie * MeSH
• gramnegativní bakterie účinky léků   MeSH
• grampozitivní bakterie účinky léků   MeSH
• HeLa buňky MeSH
• kationty chemická syntéza   chemie   farmakologie   MeSH
• léky antitumorózní - screeningové testy MeSH
• lidé MeSH
• ligandy MeSH
• mikrobiální testy citlivosti MeSH
• mitochondrie účinky léků   MeSH
• molekulární struktura MeSH
• molybden chemie   farmakologie   MeSH
• organokovové sloučeniny chemická syntéza   chemie   farmakologie   MeSH
• proliferace buněk účinky léků   MeSH
• singletový kyslík chemie   metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Triphenylphosphonium (TPP) derivatives are commonly used to target chemical into mitochondria. We show that alkyl-TPP cause reversible, dose- and hydrophobicity-dependent alterations of mitochondrial morphology and function and a selective decrease of mitochondrial inner membrane proteins including subunits of the respiratory chain complexes, as well as components of the mitochondrial calcium uniporter complex. The treatment with alkyl-TPP resulted in the cleavage of the pro-fusion and cristae organisation regulator Optic atrophy-1. The structural and functional effects of alkyl-TPP were found to be reversible and not merely due to loss of membrane potential. A similar effect was observed with the mitochondria-targeted antioxidant MitoQ.

• MeSH
• antioxidancia * farmakologie   MeSH
• kationty metabolismus   farmakologie   MeSH
• membránové proteiny metabolismus   MeSH
• membránový potenciál mitochondrií MeSH
• mitochondriální membrány metabolismus   MeSH
• mitochondrie * metabolismus   MeSH
• organofosforové sloučeniny farmakologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Letm1 is a conserved protein in eukaryotes bearing energized mitochondria. Hemizygous deletion of its gene has been implicated in symptoms of the human disease Wolf-Hirschhorn syndrome. Studies almost exclusively performed in opisthokonts have attributed several roles to Letm1, including maintaining mitochondrial morphology, mediating either calcium or potassium/proton antiport, and facilitating mitochondrial translation. We address the ancestral function of Letm1 in the highly diverged protist and significant pathogen, Trypanosoma brucei. We demonstrate that Letm1 is involved in maintaining mitochondrial volume via potassium/proton exchange across the inner membrane. This role is essential in the vector-dwelling procyclic and mammal-infecting bloodstream stages as well as in Trypanosoma brucei evansi, a form of the latter stage lacking an organellar genome. In the pathogenic bloodstream stage, the mitochondrion consumes ATP to maintain an energized state, whereas that of T. brucei evansi also lacks a conventional proton-driven membrane potential. Thus, Letm1 performs its function in different physiological states, suggesting that ion homeostasis is among the few characterized essential pathways of the mitochondrion at this T. brucei life stage. Interestingly, Letm1 depletion in the procyclic stage can be complemented by exogenous expression of its human counterpart, highlighting the conservation of protein function between highly divergent species. Furthermore, although mitochondrial translation is affected upon Letm1 ablation, it is an indirect consequence of K(+) accumulation in the matrix.

• MeSH
• antibakteriální látky farmakologie   MeSH
• draslík metabolismus   MeSH
• fenotyp MeSH
• homeostáza MeSH
• kationty MeSH
• lidé MeSH
• membránový potenciál mitochondrií MeSH
• mitochondriální proteiny chemie   metabolismus   fyziologie   MeSH
• mitochondrie metabolismus   MeSH
• proteosyntéza MeSH
• protozoální proteiny chemie   metabolismus   fyziologie   MeSH
• průtoková cytometrie metody   MeSH
• RNA interference MeSH
• testy genetické komplementace MeSH
• Trypanosoma brucei brucei metabolismus   MeSH
• umlčování genů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The mechanism of cyanide's inhibitory effect on the mitochondrial cytochrome c oxidase (COX) as well as the conditions for its recovery have not yet been fully explained. We investigated three parameters of COX function, namely electron transport (oxygen consumption), proton transport (mitochondrial membrane potential Δψ(m)) and the enzyme affinity to oxygen (p₅₀ value) with regard to the inhibition by KCN and its reversal by pyruvate. 250 μM KCN completely inhibited both the electron and proton transport function of COX. The inhibition was reversible as demonstrated by washing of mitochondria. The addition of 60 mM pyruvate induced the maximal recovery of both parameters to 60-80% of the original values. When using low KCN concentrations of up to 5 μM, we observed a profound, 30-fold decrease of COX affinity for oxygen. Again, this decrease was completely reversed by washing mitochondria while pyruvate induced only a partial, yet significant recovery of oxygen affinity. Our results demonstrate that the inhibition of COX by cyanide is reversible and that the potential of pyruvate as a cyanide poisoning antidote is limited. Importantly, we also showed that the COX affinity for oxygen is the most sensitive indicator of cyanide toxic effects.

• MeSH
• játra metabolismus   MeSH
• krysa rodu rattus MeSH
• kyanid draselný farmakologie   MeSH
• kyselina pyrohroznová metabolismus   MeSH
• kyslík metabolismus   MeSH
• membránový potenciál mitochondrií fyziologie   MeSH
• mitochondrie metabolismus   MeSH
• potkani Wistar MeSH
• protony MeSH
• respirační komplex IV antagonisté a inhibitory   metabolismus   MeSH
• spotřeba kyslíku fyziologie   MeSH
• transport elektronů fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• biologický transport MeSH
• elektrofyziologie MeSH
• kationty dvojmocné metabolismus   MeSH
• kationty jednomocné metabolismus   MeSH
• mitochondrie fyziologie   metabolismus   MeSH
• permeabilita buněčné membrány MeSH
• Publikační typ
• přehledy MeSH

Adenine nucleotide translocase (ANT) is a well-known mitochondrial exchanger of ATP against ADP. In contrast, few studies have shown that ANT also mediates proton transport across the inner mitochondrial membrane. The results of these studies are controversial and lead to different hypotheses about molecular transport mechanisms. We hypothesized that the H+-transport mediated by ANT and uncoupling proteins (UCP) has a similar regulation pattern and can be explained by the fatty acid cycling concept. The reconstitution of purified recombinant ANT1 in the planar lipid bilayers allowed us to measure the membrane current after the direct application of transmembrane potential ΔΨ, which would correspond to the mitochondrial states III and IV. Experimental results reveal that ANT1 does not contribute to a basal proton leak. Instead, it mediates H+ transport only in the presence of long-chain fatty acids (FA), as already known for UCPs. It depends on FA chain length and saturation, implying that FA's transport is confined to the lipid-protein interface. Purine nucleotides with the preference for ATP and ADP inhibited H+ transport. Specific inhibitors of ATP/ADP transport, carboxyatractyloside or bongkrekic acid, also decreased proton transport. The H+ turnover number was calculated based on ANT1 concentration determined by fluorescence correlation spectroscopy and is equal to 14.6 ± 2.5 s-1. Molecular dynamic simulations revealed a large positively charged area at the protein/lipid interface that might facilitate FA anion's transport across the membrane. ANT's dual function-ADP/ATP and H+ transport in the presence of FA-may be important for the regulation of mitochondrial membrane potential and thus for potential-dependent processes in mitochondria. Moreover, the expansion of proton-transport modulating drug targets to ANT1 may improve the therapy of obesity, cancer, steatosis, cardiovascular and neurodegenerative diseases.

• MeSH
• iontový transport MeSH
• konformace proteinů MeSH
• mastné kyseliny metabolismus   MeSH
• membránový potenciál mitochondrií MeSH
• mitochondrie metabolismus   MeSH
• myši MeSH
• protony * MeSH
• translokátor adeninových nukleotidů 1 chemie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• cytochromy c fyziologie   MeSH
• kyslík metabolismus   MeSH
• mitochondrie enzymologie   MeSH
• protony MeSH
• respirační komplex IV analýza   fyziologie   chemie   MeSH
• transport elektronů genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• přehledy MeSH