Sterols perform essential structural and signalling functions in living organisms. Ergosterol contributes to the fluidity, permeability, microdomain formation and functionality of proteins in the yeast membrane. In our study, desmosterol was the most successful at compensating for the lack of ergosterol in Saccharomyces cerevisiae, besides stigmasterol and sitosterol. These three sterols supported cell growth without causing severe morphological defects, unlike cholesterol, 7-dehydrocholesterol, lathosterol, cholestanol or lanosterol. Together with ergosterol, they were also able to bring the plasma membrane potential of hem1Δ cells closer to the level of the wild type. In addition, desmosterol conferred even higher thermotolerance to yeast than ergosterol. Some sterols counteracted the antifungal toxicity of polyenes, azoles and terbinafine to hem1Δ cells. Plant sterols (stigmasterol, sitosterol) and desmosterol ensured the glucose-induced activation of H+-ATPase in hem1Δ cells analogously to ergosterol, whereas cholesterol and 7-dehydrocholesterol were less effective. Exogenous ergosterol, stigmasterol, sitosterol, desmosterol and cholesterol also improved the growth of Candida glabrata and Candida albicans in the presence of inhibitory concentration of fluconazole. The proper incorporation of exogenous sterols into the membrane with minimal adverse side effects on membrane functions was mainly influenced by the structure of the sterol acyl chain, and less by their ring structures.
- Klíčová slova
- Ergosterol, H(+)-ATPase, Multidrug resistance, Plasma membrane, Yeast, diS-C(3)(3) assay,
- MeSH
- antifungální látky * farmakologie MeSH
- buněčná membrána * účinky léků metabolismus fyziologie MeSH
- desmosterol metabolismus farmakologie MeSH
- ergosterol * metabolismus farmakologie MeSH
- fungální léková rezistence * MeSH
- mikrobiální testy citlivosti MeSH
- protonové ATPasy * metabolismus MeSH
- Saccharomyces cerevisiae - proteiny metabolismus genetika MeSH
- Saccharomyces cerevisiae * účinky léků enzymologie fyziologie metabolismus MeSH
- sitosteroly metabolismus farmakologie MeSH
- steroly * metabolismus farmakologie MeSH
- stigmasterol metabolismus farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- antifungální látky * MeSH
- desmosterol MeSH
- ergosterol * MeSH
- protonové ATPasy * MeSH
- Saccharomyces cerevisiae - proteiny MeSH
- sitosteroly MeSH
- steroly * MeSH
- stigmasterol MeSH
The effectivity of utilization of exogenous sterols in the yeast Saccharomyces cerevisiae exposed to hypoxic stress is dependent on the sterol structure. The highly imported sterols include animal cholesterol or plant sitosterol, while ergosterol, typical of yeasts, is imported to a lesser extent. An elevated utilization of non-yeast sterols is associated with their high esterification and relocalization to lipid droplets (LDs). Here we present data showing that LDs and sterol esterification play a critical role in the regulation of the accumulation of non-yeast sterols in membranes. Failure to form LDs during anaerobic growth in media supplemented with cholesterol or sitosterol resulted in an extremely long lag phase, in contrast to normal growth in media with ergosterol or plant stigmasterol. Moreover, in hem1∆, which mimics anaerobiosis, neither cholesterol nor sitosterol supported the growth in an LD-less background. The incorporation of non-ergosterol sterols into the membranes affected fundamental membrane characteristics such as relative membrane potential, permeability, tolerance to osmotic stress and the formation of membrane domains. Our findings reveal that LDs assume an important role in scenarios wherein cells are dependent on the utilization of exogenous lipids, particularly under anoxia. Given the diverse lipid structures present in yeast niches, LDs fulfil a protective role, mitigating the risk of excessive accumulation of potentially toxic steroids and fatty acids in the membranes. Finally, we present a novel function for sterols in a model eukaryotic cell - alleviation of the lipotoxicity of unsaturated fatty acids.
- Klíčová slova
- Fatty acid, Lipid droplet, Lipotoxicity, Plasma membrane, Relative membrane potential, Sterol,
- MeSH
- anaerobióza MeSH
- buněčná membrána metabolismus účinky léků MeSH
- cholesterol metabolismus MeSH
- ergosterol metabolismus MeSH
- esterifikace MeSH
- fyziologický stres MeSH
- lipidová tělíska * metabolismus MeSH
- Saccharomyces cerevisiae - proteiny metabolismus genetika MeSH
- Saccharomyces cerevisiae * metabolismus růst a vývoj účinky léků MeSH
- steroly * metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- cholesterol MeSH
- ergosterol MeSH
- Saccharomyces cerevisiae - proteiny MeSH
- steroly * MeSH
Barth syndrome (BTHS) is an inherited mitochondrial disorder characterized by a decrease in total cardiolipin and the accumulation of its precursor monolysocardiolipin due to the loss of the transacylase enzyme tafazzin. However, the molecular basis of BTHS pathology is still not well understood. Here we characterize the double mutant pgc1Δtaz1Δ of Saccharomyces cerevisiae deficient in phosphatidylglycerol-specific phospholipase C and tafazzin as a new yeast model of BTHS. Unlike the taz1Δ mutant used to date, this model accumulates phosphatidylglycerol, thus better approximating the human BTHS cells. We demonstrate that increased phosphatidylglycerol in this strain leads to more pronounced mitochondrial respiratory defects and an increased incidence of aberrant mitochondria compared to the single taz1Δ mutant. We also show that the mitochondria of the pgc1Δtaz1Δ mutant exhibit a reduced rate of respiration due to decreased cytochrome c oxidase and ATP synthase activities. Finally, we determined that the mood-stabilizing anticonvulsant valproic acid has a positive effect on both lipid composition and mitochondrial function in these yeast BTHS models. Overall, our results show that the pgc1Δtaz1Δ mutant better mimics the cellular phenotype of BTHS patients than taz1Δ cells, both in terms of lipid composition and the degree of disruption of mitochondrial structure and function. This favors the new model for use in future studies.
- Klíčová slova
- Barth syndrome, mitochondria, phosphatidylglycerol, tafazzin, valproic acid,
- MeSH
- acyltransferasy metabolismus MeSH
- Barthův syndrom * metabolismus MeSH
- fenotyp MeSH
- fosfatidylglyceroly * antagonisté a inhibitory metabolismus MeSH
- kardiolipiny * genetika metabolismus MeSH
- lidé MeSH
- Saccharomyces cerevisiae metabolismus MeSH
- transkripční faktory metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- acyltransferasy MeSH
- fosfatidylglyceroly * MeSH
- kardiolipiny * MeSH
- TAFAZZIN protein, human MeSH Prohlížeč
- transkripční faktory MeSH
Squalene is a naturally occurring triterpene with wide industrial applications. Due to limited natural resources, production of this valuable lipid in yeast is of high commercial relevance. Typically low levels of squalene in yeast can be significantly increased by specific cultivation conditions or genetic modifications. Under normal conditions, excess squalene is stored in lipid droplets (LD), while in a Saccharomyces cerevisiae mutant unable to form LD it is distributed to cellular membranes. We present here the evidence that squalene accumulation in this LD-less mutant treated with squalene monooxygenase inhibitor terbinafine induces growth defects and loss of viability. We show that plasma membrane malfunction is involved in squalene toxicity. We have found that subinhibitory concentrations of terbinafine increased the sensitivity of LD-less mutant to several membrane-active substances. Furthermore, squalene accumulation in terbinafine-treated LD-less cells disturbed the maintenance of membrane potential and increased plasma membrane permeability to rhodamine 6G. LD-less cells treated with terbinafine showed also high sensitivity to osmotic stress. To confirm the causal relationship between squalene accumulation, loss of viability and impaired plasma membrane functions we treated LD-less cells simultaneously with terbinafine and squalene synthase inhibitor zaragozic acid. Reduction of squalene levels by zaragozic acid improved cell growth and viability and decreased plasma membrane permeability to rhodamine 6G in terbinafine-treated LD-less cells. Our results support the hypothesis that plasma membrane malfunction is involved in the mechanisms of squalene lipotoxicity in yeast cells with defective lipid storage.
- Klíčová slova
- lipid droplet, lipotoxicity, plasma membrane, squalene, yeast,
- MeSH
- buněčná membrána patologie MeSH
- lipidová tělíska chemie MeSH
- permeabilita buněčné membrány MeSH
- rhodaminy farmakologie MeSH
- Saccharomyces cerevisiae účinky léků genetika MeSH
- skvalen toxicita MeSH
- terbinafin farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- rhodamine 6G MeSH Prohlížeč
- rhodaminy MeSH
- skvalen MeSH
- terbinafin MeSH
Naturally occurring antimicrobial peptides and their synthetic analogues are promising candidates for new antifungal drugs. We focused on three groups of peptides isolated from the venom of bees and their synthetic analogues (lasioglossins, halictines and hylanines), which all rapidly permeabilised the plasma membrane. We compared peptides' potency against six pathogenic Candida species (C. albicans, C. glabrata, C. parapsilosis, C. tropicalis, C. krusei and C. dubliniensis) and the non-pathogenic model yeast Saccharomyces cerevisiae. Their activity was independent of the presence of the multidrug-resistant pumps of C. glabrata but was influenced by the lipid composition of cell plasma membranes. Although the direct interaction of the peptides with ergosterol was negligible in comparison with amphotericin B, the diminished ergosterol content after terbinafine pretreatment resulted in an increased resistance of C. glabrata to the peptides. The tested peptides strongly interacted with phosphatidylglycerol, phosphatidic acid and cardiolipin and partly with phosphatidylinositol and phosphatidylethanolamine. The interactions between predominantly anionic phospholipids and cationic peptides indicated a mainly electrostatic binding of peptides to the membranes. The results obtained also pointed to a considerable role of the components of lipid rafts (composed from sphingolipids and ergosterol) in the interaction of yeast cells with the peptides.
- Klíčová slova
- Antimicrobial peptides, Candida, diS-C3(3) assay, membrane lipids, membrane potential, yeast,
- MeSH
- antifungální látky farmakologie MeSH
- buněčná membrána účinky léků MeSH
- Candida účinky léků MeSH
- ergosterol metabolismus MeSH
- fungální léková rezistence účinky léků MeSH
- hmyz metabolismus MeSH
- membránové lipidy metabolismus MeSH
- mikrobiální testy citlivosti metody MeSH
- peptidy farmakologie MeSH
- Saccharomyces cerevisiae účinky léků MeSH
- včelí jedy farmakologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- antifungální látky MeSH
- ergosterol MeSH
- membránové lipidy MeSH
- peptidy MeSH
- včelí jedy MeSH
