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Verdaguer IB, Crispim M, Zafra CA, Sussmann RAC, Buriticá NL, Melo HR, Azevedo MF, Almeida FG, Kimura EA, Katzin AM. Exploring Ubiquinone Biosynthesis Inhibition as a Strategy for Improving Atovaquone Efficacy in Malaria. Antimicrob Agents Chemother 2021; 65:e01516-20. [PMID: 33495230 DOI: 10.1128/AAC.01516-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 01/16/2021] [Indexed: 11/20/2022] Open
Abstract
Atovaquone (AV) acts on the malaria parasite by competing with ubiquinol (UQH2) for its union to the mitochondrial bc1 complex, preventing the ubiquinone-8 and ubiquinone-9 (UQ-8 and UQ-9) redox recycling, which is a necessary step in pyrimidine biosynthesis. This study focused on UQ biosynthesis in Plasmodium falciparum and adopted proof-of-concept research to better elucidate the mechanism of action of AV and improve its efficacy. Initially, UQ biosynthesis was evaluated using several radioactive precursors and chromatographic techniques. This methodology was suitable for studying the biosynthesis of both UQ homologs and its redox state. Additionally, the composition of UQ was investigated in parasites cultivated at different oxygen saturations or in the presence of AV. AV affected the redox states of both UQ-8 and UQ-9 homologs by increasing the levels of the respective reduced forms. Conversely, low-oxygen environments specifically inhibited UQ-9 biosynthesis and increased the antimalarial efficacy of AV. These findings encouraged us to investigate the biological importance and the potential of UQ biosynthesis as a drug target based on its inhibition by 4-nitrobenzoate (4-NB), a 4-hydroxybenzoate (4-HB) analog. 4-NB effectively inhibits UQ biosynthesis and enhances the effects of AV on parasitic growth and respiration rate. Although 4-NB itself exhibits poor antimalarial activity, its 50% inhibitory concentration (IC50) value increased significantly in the presence of a soluble UQ analog, p-aminobenzoic acid (pABA), or 4-HB. These results indicate the potential of AV combined with 4-NB as a novel therapy for malaria and other diseases caused by AV-sensitive pathogens.
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Liparulo I, Bergamini C, Bortolus M, Calonghi N, Gasparre G, Kurelac I, Masin L, Rizzardi N, Rugolo M, Wang W, Aleo SJ, Kiwan A, Torri C, Zanna C, Fato R. Coenzyme Q biosynthesis inhibition induces HIF-1α stabilization and metabolic switch toward glycolysis. FEBS J 2020; 288:1956-1974. [PMID: 32898935 DOI: 10.1111/febs.15561] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 07/16/2020] [Accepted: 09/03/2020] [Indexed: 12/28/2022]
Abstract
Coenzyme Q10 (CoQ, ubiquinone) is a redox-active lipid endogenously synthesized by the cells. The final stage of CoQ biosynthesis is performed at the mitochondrial level by the 'complex Q', where coq2 is responsible for the prenylation of the benzoquinone ring of the molecule. We report that the competitive coq2 inhibitor 4-nitrobenzoate (4-NB) decreased the cellular CoQ content and caused severe impairment of mitochondrial function in the T67 human glioma cell line. In parallel with the reduction in CoQ biosynthesis, the cholesterol level increased, leading to significant perturbation of the plasma membrane physicochemical properties. We show that 4-NB treatment did not significantly affect the cell viability, because of an adaptive metabolic rewiring toward glycolysis. Hypoxia-inducible factor 1α (HIF-1α) stabilization was detected in 4-NB-treated cells, possibly due to the contribution of both reduction in intracellular oxygen tension and ROS overproduction. Exogenous CoQ supplementation partially recovered cholesterol content, HIF-1α degradation, and ROS production, whereas only weakly improved the bioenergetic impairment induced by the CoQ depletion. Our data provide new insights on the effect of CoQ depletion and contribute to shed light on the pathogenic mechanisms of ubiquinone deficiency syndrome.
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Affiliation(s)
- Irene Liparulo
- Department of Pharmacy and Biotechnology-FABIT, University of Bologna, Italy
| | - Christian Bergamini
- Department of Pharmacy and Biotechnology-FABIT, University of Bologna, Italy
| | | | - Natalia Calonghi
- Department of Pharmacy and Biotechnology-FABIT, University of Bologna, Italy
| | - Giuseppe Gasparre
- Department of Medical and Surgical Sciences - DIMEC, University of Bologna, Italy
| | - Ivana Kurelac
- Department of Medical and Surgical Sciences - DIMEC, University of Bologna, Italy
| | - Luca Masin
- Department of Pharmacy and Biotechnology-FABIT, University of Bologna, Italy
| | - Nicola Rizzardi
- Department of Pharmacy and Biotechnology-FABIT, University of Bologna, Italy
| | - Michela Rugolo
- Department of Pharmacy and Biotechnology-FABIT, University of Bologna, Italy
| | - Wenping Wang
- Department of Pharmacy and Biotechnology-FABIT, University of Bologna, Italy
| | - Serena J Aleo
- Department of Pharmacy and Biotechnology-FABIT, University of Bologna, Italy
| | - Alisar Kiwan
- Department of Chemistry 'Giacomo Ciamician', University of Bologna, Italy
| | - Cristian Torri
- Department of Chemistry 'Giacomo Ciamician', University of Bologna, Italy
| | - Claudia Zanna
- Department of Pharmacy and Biotechnology-FABIT, University of Bologna, Italy
| | - Romana Fato
- Department of Pharmacy and Biotechnology-FABIT, University of Bologna, Italy
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Abstract
Arthrobacter sp. SPG utilized 2-nitrobenzoate as its sole source of carbon and energy and degraded it with accumulation of stoichiometric amounts of nitrite ions. Salicylate and catechol were detected as metabolites of the 2-nitrobenzoate degradation using high performance liquid chromatography and gas chromatography-mass spectrometry. Enzyme activities for 2-nitrobenzoate-2-monooxygenase, salicylate hydroxylase, and catechol-1,2-dioxygenase were detected in the crude extracts of the 2-nitrobenzoate-induced cells of strain SPG. The 2-nitrobenzoate-monooxygenase activity resulted in formation of salicylate and nitrite from 2-nitrobenzoate, whereas salicylate hydroxylase catalyzed the conversion of salicylate to catechol. The ring-cleaving enzyme, catechol-1,2-dioxygenase cleaved catechol to cis,cis-muconic acid. Cells of strain SPG were able to degrade 2-nitrobenzoate in sterile as well as non-sterile soil microcosms. The results of microcosm studies showed that strain SPG degraded more than 90% of 2-nitrobenzoate within 10-12 days. This study clearly shows that Arthrobacter sp. SPG degraded 2-nitrobenzoate via a new pathway with formation of salicylate and catechol as metabolites. Arthrobacter sp. SPG may be used for bioremediation of 2-nitrobenzoate-contaminated sites due to its ability to degrade 2-nitrobenzoate in soil.
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Affiliation(s)
- Pankaj K Arora
- School of Biotechnology, Yeungnam University Gyeongsan, South Korea
| | - Ashutosh Sharma
- Escuela de Ingenieria en Alimentos, Biotecnologia y Agronomia, Instituto Tecnológico y de Estudios Superiores de Monterrey San Pablo, Mexico
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