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Nature Chemical Biology Jan 2017Small molecules are pharmacological tools of considerable value for dissecting complex biological processes and identifying potential therapeutic interventions.... (Review)
Review
Small molecules are pharmacological tools of considerable value for dissecting complex biological processes and identifying potential therapeutic interventions. Recently, the cellular quality-control process of mitophagy has attracted considerable research interest; however, the limited availability of suitable chemical probes has restricted our understanding of the molecular mechanisms involved. Current approaches to initiate mitophagy include acute dissipation of the mitochondrial membrane potential (ΔΨ) by mitochondrial uncouplers (for example, FCCP/CCCP) and the use of antimycin A and oligomycin to impair respiration. Both approaches impair mitochondrial homeostasis and therefore limit the scope for dissection of subtle, bioenergy-related regulatory phenomena. Recently, novel mitophagy activators acting independently of the respiration collapse have been reported, offering new opportunities to understand the process and potential for therapeutic exploitation. We have summarized the current status of mitophagy modulators and analyzed the available chemical tools, commenting on their advantages, limitations and current applications.
Topics: Antimycin A; Humans; Membrane Potential, Mitochondrial; Mitochondria; Mitophagy; Molecular Structure; Oligomycins
PubMed: 28103219
DOI: 10.1038/nchembio.2287 -
Autophagy May 2023Macroautophagy/autophagy or mitophagy plays crucial roles in the maintenance of pancreatic β-cell function. PPP3/calcineurin can modulate the activity of TFEB, a master...
Macroautophagy/autophagy or mitophagy plays crucial roles in the maintenance of pancreatic β-cell function. PPP3/calcineurin can modulate the activity of TFEB, a master regulator of lysosomal biogenesis and autophagy gene expression, through dephosphorylation. We studied whether PPP3/calcineurin inhibitors can affect the mitophagy of pancreatic β-cells and pancreatic β-cell function employing FK506, an immunosuppressive drug against graft rejection. FK506 suppressed rotenone- or oligomycin+antimycin-A-induced mitophagy measured by Mito-Keima localization in acidic lysosomes or RFP-LC3 puncta colocalized with TOMM20 in INS-1 insulinoma cells. FK506 diminished nuclear translocation of TFEB after treatment with rotenone or oligomycin+antimycin A. Forced TFEB nuclear translocation by a constitutively active TFEB mutant transfection restored impaired mitophagy by FK506, suggesting the role of decreased TFEB nuclear translocation in FK506-mediated mitophagy impairment. Probably due to reduced mitophagy, recovery of mitochondrial potential or quenching of mitochondrial ROS after removal of rotenone or oligomycin+antimycin A was delayed by FK506. Mitochondrial oxygen consumption was reduced by FK506, indicating reduced mitochondrial function by FK506. Likely due to mitochondrial dysfunction, insulin release from INS-1 cells was reduced by FK506 in vitro. FK506 treatment also reduced insulin release and impaired glucose tolerance in vivo, which was associated with decreased mitophagy and mitochondrial COX activity in pancreatic islets. FK506-induced mitochondrial dysfunction and glucose intolerance were ameliorated by an autophagy enhancer activating TFEB. These results suggest that diminished mitophagy and consequent mitochondrial dysfunction of pancreatic β-cells contribute to FK506-induced β-cell dysfunction or glucose intolerance, and autophagy enhancement could be a therapeutic modality against post-transplantation diabetes mellitus caused by PPP3/calcineurin inhibitors.
Topics: Humans; Mitophagy; Autophagy; Calcineurin Inhibitors; Tacrolimus; Antimycin A; Glucose Intolerance; Rotenone; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Lysosomes; Oligomycins; Insulins
PubMed: 36217215
DOI: 10.1080/15548627.2022.2132686 -
Applied and Environmental Microbiology Apr 2022Zinc is an essential cofactor for many metal enzymes and transcription regulators. Zn availability has long been known to affect antibiotic production and morphological...
Zinc is an essential cofactor for many metal enzymes and transcription regulators. Zn availability has long been known to affect antibiotic production and morphological differentiation of species. However, the molecular mechanism whereby zinc regulates these processes remains unclear. We investigated the regulatory roles of the zinc-sensing regulator Zur in Streptomyces avermitilis. Our findings demonstrate that Zur plays an essential role in maintaining zinc homeostasis by repressing the expression of the zinc uptake system ZnuACB and alternative non-zinc-binding ribosomal proteins and promoting the expression of zinc exporter ZitB. Deletion of the gene resulted in decreased production of avermectin and oligomycin and delayed morphological differentiation, and these parameters were restored close to wild-type levels in a -complemented strain. Zur bound specifically to Zur box in the promoter regions of avermectin pathway-specific activator gene , oligomycin polyketide synthase gene , and filipin biosynthetic pathway-specific regulatory genes and . Analyses by reverse transcription quantitative PCR and luciferase reporter systems indicated that Zur directly activates the transcription of these genes, i.e., that Zur directly activates biosynthesis of avermectin and oligomycin. Zur positively regulated morphological development by repressing the transcription of differentiation-related genes and . Our findings, taken together, demonstrate that Zur in directly controls zinc homeostasis, biosynthesis of avermectin and oligomycin, and morphological differentiation. Biosynthesis of secondary metabolites and morphological differentiation in bacteria are affected by environmental signals. The molecular mechanisms whereby zinc availability affects secondary metabolism and morphological differentiation remain poorly understood. We identified several new target genes of the zinc response regulator Zur in Streptomyces avermitilis, the industrial producer of avermectin. Zur was found to directly and positively control avermectin production, oligomycin production, and morphological differentiation in response to extracellular Zn levels. Our findings clarify the regulatory functions of Zur in , which involve linking environmental Zn status with control of antibiotic biosynthetic pathways and morphological differentiation.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Gene Expression Regulation, Bacterial; Homeostasis; Ivermectin; Oligomycins; Secondary Metabolism; Streptomyces; Zinc
PubMed: 35323024
DOI: 10.1128/aem.00278-22 -
International Journal of Experimental... Dec 2023This study aimed to investigate the effects of mitochondrial homeostasis on lipopolysaccharide (LPS)-induced endothelial cell barrier function and the mechanisms that...
This study aimed to investigate the effects of mitochondrial homeostasis on lipopolysaccharide (LPS)-induced endothelial cell barrier function and the mechanisms that underlie these effects. Cells were treated with LPS or oligomycin (mitochondrial adenosine triphosphate synthase inhibitor) and the mitochondrial morphology, mitochondrial reactive oxygen species (mtROS), and mitochondrial membrane potential (ΔΨm) were evaluated. Moreover, the shedding of glycocalyx-heparan sulphate (HS), the levels of HS-specific degrading enzyme heparanase (HPA), and the expression of occludin and zonula occludens (ZO-1) of Tight Junctions (TJ)s, which are mediated by myosin light chain phosphorylation (p-MLC), were assessed. Examining the changes in mitochondrial homeostasis showed that adding heparinase III, which is an exogenous HPA, can destroy the integrity of glycocalyx. LPS simultaneously increased mitochondrial swelling, mtROS, and ΔΨm. Without oligomycin effects, HS, HPA levels, and p-MLC were found to be elevated, and the destruction of occludin and ZO-1 increased. Heparinase III not only damaged the glycocalyx by increasing HS shedding but also increased mitochondrial swelling and mtROS and decreased ΔΨm. Mitochondrial homeostasis is involved in LPS-induced endothelial cell barrier dysfunction by aggravating HPA and p-MLC levels. In turn, the integrated glycocalyx protects mitochondrial homeostasis.
Topics: Lipopolysaccharides; Occludin; Endothelial Cells; Tight Junctions; Oligomycins
PubMed: 37828780
DOI: 10.1111/iep.12495 -
Zhong Nan Da Xue Xue Bao. Yi Xue Ban =... Feb 2021Radiotherapy is one of the main therapies for colorectal cancer, but radioresistance often leads to radiotherapy failure. To improve the radioresistance, we explore the...
OBJECTIVES
Radiotherapy is one of the main therapies for colorectal cancer, but radioresistance often leads to radiotherapy failure. To improve the radioresistance, we explore the effect of oligomycin A, the H-ATP synthase inhibitor, on the sensitivity of HT29 colorectal cancer cells to irradiation and its underlying mechanisms.
METHODS
The effects of different concentrations of oligomycin A on the survival rate and glycolysis of HT29 colorectal cancer cells at different time points were investigated via MTT and glycolysis assay. siRNA-PFK1 was synthesized in vitro and transfected into HT29 cells. The effects of oligomycin A on radiosensitivity of HT29 colorectal cancer cells were measured via MTT and colony formation assay. Western blotting was used to detect the effect of oligomycin A on the expression of glycolytic enzyme PFK1. We compared difference between the effects of siRNA-PFK1 group and oligomycin A combined with siRNA-PFK1 group on cell survival and glycolysis. After 4 Gy X-ray irradiation, the effects of cell survival and glycolysis between the siRNA-PFK1 group and the oligomycin A combined with siRNA-PFK1 group were compared.
RESULTS
Compared with the 0 μmol/L oligomycin A group, the cell survival rate of HT29 cells treated with 4 μmol/L oligomycin A was significantly increased (<0.05), and the glucose uptake, the lactic acid, and the ATP production were also significantly increased (all <0.01). After X-ray irradiation at different doses (0, 2, 4, 6, and 8 Gy), the colony formation rate and cell survival rate of the 4 μmol/L oligomycin A treated group were significantly higher than those in the 0 μmol/L oligomycin A group (both <0.01). The sensitization enhancement ratio of oligomycin A on HT29 colorectal cancer cells was 0.4886. The expression of PFK1 in the 4 μmol/L oligomycin A group was significantly higher than that in the 0 μmol/L oligomycin A group (<0.001). The glycolysis level, colony formation rate, and cell survival rate of the siRNA-PFK1 HT29 cells group were significantly lower than those in the 0 μmol/L oligomycin A group (all <0.05), while the results in the 4 μmol/L oligomycin A combined with siRNA-PFK1 group were significantly higher than those in the siRNA-PFK1 group (all <0.001). After 4 Gy X-ray irradiation, the colony formation rate and cell survival rate in the siRNA-PFK1 group were decreased compared with those in the irradiation group (<0.01 or <0.001), while the results of the 4 μmol/L oligomycin A combined with siRNA-PFK1 group were significantly higher than those in the siRNA-PFK1 group (both <0.001).
CONCLUSIONS
Oligomycin A can promote the radioresistance of HT29 colorectal cancer cells, which may be related to up-regulation of the PFK1 expression and increase of cell glycolysis.
Topics: Cell Line, Tumor; Colorectal Neoplasms; HT29 Cells; Humans; Oligomycins; Radiation Tolerance
PubMed: 33678646
DOI: 10.11817/j.issn.1672-7347.2021.200063 -
Cardiovascular Therapeutics 2008The mitochondrial F1F0 ATP synthase is responsible for the majority of ATP production in mammals and does this through a rotary catalytic mechanism. Studies show that... (Review)
Review
The mitochondrial F1F0 ATP synthase is responsible for the majority of ATP production in mammals and does this through a rotary catalytic mechanism. Studies show that the F1F0 ATP synthase can switch to an ATP hydrolase, and this occurs under conditions seen during myocardial ischemia. This ATP hydrolysis causes wasting of ATP that does not produce work. The degree of ATP inefficiently hydrolyzed during ischemia may be as high as 50-90% of the total. A naturally occurring, reversible inhibitor (IF-1) of the hydrolase activity is in the mitochondria, and it has a pH optimum of 6.8. Based on studies with the nonselective (inhibit both synthase and hydrolase activity) inhibitors aurovertin B and oligomycin B reduce the rate of ATP depletion during ischemia, showing that IF-1 does not completely block hydrolase activity. Oligomycin and aurovertin cannot be used for treating myocardial ischemia as they will reduce ATP production in healthy tissue. We generated a focused structure-activity relationship, and several compounds were identified that selectively inhibited the F1F0 ATP hydrolase activity while having no effect on synthase function. One compound, BMS-199264 had no effect on F1F0 ATP synthase function in submitochondrial particles while inhibiting hydrolase function, unlike oligomycin that inhibits both. BMS-199264 selectively inhibited ATP decline during ischemia while not affecting ATP production in normoxic and reperfused hearts. BMS-191264 also reduced cardiac necrosis and enhanced the recovery of contractile function following reperfusion. These data also suggest that the reversal of the synthase and hydrolase activities is not merely a chemical reaction run in reverse.
Topics: Animals; Aurovertins; Enzyme Inhibitors; Imidazoles; Mitochondria; Mitochondrial Proton-Translocating ATPases; Myocardial Ischemia; Oligomycins; Prokaryotic Initiation Factor-1; Proton-Translocating ATPases; Structure-Activity Relationship
PubMed: 19035880
DOI: 10.1111/j.1755-5922.2008.00065.x -
The Biochemical Journal Jun 19651. Investigation of a number of reactions involving both internal and externally added adenine nucleotides of isolated liver mitochondria has revealed that atractylate...
1. Investigation of a number of reactions involving both internal and externally added adenine nucleotides of isolated liver mitochondria has revealed that atractylate and oligomycin differ markedly in the site of their inhibitory action. 2. Both atractylate and oligomycin inhibited the respiratory-chain-level phosphorylation of added ADP. Neither compound inhibited the substrate-level phosphorylation of internal (endogenous) ADP or the respiration-dependent accumulation of bivalent metal ions (Ca(2+), Sr(2+) or Mn(2+)). 3. Atractylate, but not oligomycin, inhibited the substrate-level phosphorylation of externally added ADP, the ATP- and carnitine-dependent reduction of nicotinamide nucleotide by palmitate and the ATP-induced activation of succinate oxidation. 4. Oligomycin, but not atractylate, inhibited the respiratory-chain-linked phosphorylation of internal ADP, and the dephosphorylation of internal ATP that occurred on the addition of antimycin. 5. The enhancement of arsenate-stimulated respiration by ADP was prevented by atractylate added either before or after the ADP. Oligomycin abolished both the arsenate and ADP stimulation. 6. It is suggested that atractylate prevents the passage of adenine nucleotides across the mitochondrial membrane, whereas oligomycin interferes with the formation of a ;high-energy' phosphorylated intermediate.
Topics: Adenine Nucleotides; Adenosine Triphosphate; Anti-Bacterial Agents; Arsenicals; Atractyloside; Carnitine; Electron Transport; Glycosides; Metabolism; Mitochondria; Mitochondria, Liver; Oligomycins; Oxidation-Reduction; Oxidative Phosphorylation; Palmitic Acid; Pharmacology; Phosphotransferases; Poisons; Research; Succinates
PubMed: 14342506
DOI: 10.1042/bj0950707 -
Scientific Reports Aug 2022Mitochondrial dysfunction promotes cancer aggressiveness, metastasis, and resistance to therapy. Similar traits are associated with epithelial mesenchymal transition...
Mitochondrial dysfunction promotes cancer aggressiveness, metastasis, and resistance to therapy. Similar traits are associated with epithelial mesenchymal transition (EMT). We questioned whether mitochondrial dysfunction induces EMT in head and neck cancer (HNC) cell lines. We induced mitochondrial dysfunction in four HNC cell lines with carbonyl cyanide-4(trifluoromethoxy)phenylhydrazone (FCCP), a mitochondrial electron transport chain uncoupling agent, and oligomycin, a mitochondrial ATP synthase inhibitor. Extracellular flux analyses and expression of the cystine/glutamate antiporter system xc (xCT) served to confirm mitochondrial dysfunction. Expression of the EMT-related transcription factor SNAI2, the mesenchymal marker vimentin and vimentin/cytokeratin double positivity served to detect EMT. In addition, holotomographic microscopy was used to search for morphological features of EMT. Extracellular flux analysis and xCT expression confirmed that FCCP/oligomycin induced mitochondrial dysfunction in all cell lines. Across the four cell lines, mitochondrial dysfunction resulted in an increase in relative SNAI2 expression from 8.5 ± 0.8 to 12.0 ± 1.1 (mean ± SEM; p = 0.007). This effect was predominantly caused by the CAL 27 cell line (increase from 2.2 ± 0.4 to 5.5 ± 1.0; p < 0.001). Similarly, only in CAL 27 cells vimentin expression increased from 2.2 ± 0.5 × 10 to 33.2 ± 10.2 × 10 (p = 0.002) and vimentin/cytokeratin double positive cells increased from 34.7 ± 5.1 to 67.5 ± 9.8% (p = 0.003), while the other 3 cell lines did not respond with EMT (all p > 0.1). Across all cell lines, FCCP/oligomycin had no effect on EMT characteristics in holotomographic microscopy. Mitochondrial dysfunction induced EMT in 1 of 4 HNC cell lines. Given the heterogeneity of HNC, mitochondrial dysfunction may be sporadically induced by EMT, but EMT does not explain the tumor promoting effects of mitochondrial dysfunction in general.
Topics: Cadherins; Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; Cell Line, Tumor; Epithelial-Mesenchymal Transition; Head and Neck Neoplasms; Humans; Keratins; Mitochondria; Oligomycins; Vimentin
PubMed: 35918485
DOI: 10.1038/s41598-022-16829-5 -
PloS One 2020Oligomycins are macrolide antibiotics, produced by Streptomyces spp. that show antagonistic effects against several microorganisms such as bacteria, fungi, nematodes and...
Oligomycins are macrolide antibiotics, produced by Streptomyces spp. that show antagonistic effects against several microorganisms such as bacteria, fungi, nematodes and the oomycete Plasmopara viticola. Conidiogenesis, germination of conidia and formation of appressoria are determining factors pertaining to pathogenicity and successful diseases cycles of filamentous fungal phytopathogens. The goal of this research was to evaluate the in vitro suppressive effects of two oligomycins, oligomycin B and F along with a commercial fungicide Nativo® 75WG on hyphal growth, conidiogenesis, conidial germination, and appressorial formation of the wheat blast fungus, Magnaporthe oryzae Triticum (MoT) pathotype. We also determined the efficacy of these two oligomycins and the fungicide product in vivo in suppressing wheat blast with a detached leaf assay. Both oligomycins suppressed the growth of MoT mycelium in a dose dependent manner. Between the two natural products, oligomycin F provided higher inhibition of MoT hyphal growth compared to oligomycin B with a minimum inhibitory concentration of 0.005 and 0.05 μg/disk, respectively. The application of the compounds completely halted conidial formation of the MoT mycelium in agar medium. Further bioassays showed that these compounds significantly inhibited MoT conidia germination and induced lysis. The compounds also caused abnormal germ tube formation and suppressed appressorial formation of germinated spores. Interestingly, the application of these macrolides significantly inhibited wheat blast on detached leaves of wheat. This is the first report on the inhibition of mycelial growth, conidiogenesis, germination of conidia, deleterious morphological changes in germinated conidia, and suppression of blast disease of wheat by oligomycins from Streptomyces spp. Further study is needed to unravel the precise mode of action of these natural compounds and consider them as biopesticides for controlling wheat blast.
Topics: Biological Control Agents; Edible Grain; Food Microbiology; Fungicides, Industrial; Hyphae; Magnaporthe; Mycelium; Oligomycins; Plant Diseases; Spores, Fungal; Triticum
PubMed: 32804955
DOI: 10.1371/journal.pone.0233665 -
Cells Feb 2021Hepatocellular carcinoma (HCC) that is triggered by metabolic defects is one of the most malignant liver cancers. A much higher incidence of HCC among men than women...
Hepatocellular carcinoma (HCC) that is triggered by metabolic defects is one of the most malignant liver cancers. A much higher incidence of HCC among men than women suggests the protective roles of estrogen in HCC development and progression. To begin to understand the mechanisms involving estrogenic metabolic effects, we compared cell number, viability, cytotoxicity, and apoptosis among HCC-derived HepG2 cells that were treated with different concentrations of 2-deoxy-d-glucose (2-DG) that blocks glucose metabolism, oxamate that inhibits lactate dehydrogenase and glycolysis, or oligomycin that blocks ATP synthesis and mitochondrial oxidative phosphorylation. We confirmed that HepG2 cells primarily utilized glycolysis followed by lactate fermentation, instead of mitochondrial oxidative phosphorylation, for cell growth. We hypothesized that estrogen altered energy metabolism via its receptors to carry out its anticancer effects in HepG2 cells. We treated cells with 17β-estradiol (E2), 1,3,5-tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole (PPT) an estrogen receptor (ER) α (ERα) agonist, or 2,3-bis(4-hydroxyphenyl)-propionitrile (DPN), an ERβ agonist. We then used transcriptomic and metabolomic analyses and identified differentially expressed genes and unique metabolite fingerprints that are produced by each treatment. We further performed integrated multi-omics analysis, and identified key genes and metabolites in the gene-metabolite interaction contributed by E2 and ER agonists. This integrated transcriptomic and metabolomic study suggested that estrogen acts on estrogen receptors to suppress liver cancer cell growth via altering metabolism. This is the first exploratory study that comprehensively investigated estrogen and its receptors, and their roles in regulating gene expression, metabolites, metabolic pathways, and gene-metabolite interaction in HCC cells using bioinformatic tools. Overall, this study provides potential therapeutic targets for future HCC treatment.
Topics: Cell Count; Cell Proliferation; Deoxyglucose; Estradiol; Estrogens; Gene Expression Regulation, Neoplastic; Hep G2 Cells; Humans; Liver Neoplasms; Metabolic Networks and Pathways; Metabolome; Metabolomics; Nitriles; Oligomycins; Pyrazoles; Receptors, Estrogen; Transcriptome
PubMed: 33672651
DOI: 10.3390/cells10020455