The binuclear cyclopalladated complex CP2 is targeting ubiquinol-cytochrome c reductase (complex III) of Leishmania amazonensis
Year: 2024
Type: article
Abstract: Leishmaniasis is a neglected disease that remains with a limited number of drugs available for chemotherapy and has an increased drug resistance that affects treatment outcomes. Metal-based drugs such as cyclopalladated complex [Pd(dmba)(μ-N 3 )] 2 ( CP2 ), a Leishmania topoisomerase IB inhibitor involved in calcium dysregulation and mitochondrial dysfunction of the parasite, had been an alternative to outline the appearance of chemoresistance. To identify new molecular targets and point out possible resistance mechanisms, a CP2 -resistant Leishmania amazonensis ( LaR ) was selected by stepwise exposure to increasing drug pressure until a line capable of growth in 13.3 μM CP2 . LaR IC 50 value was 52.4 μM (4-fold higher than L. amazonensis –wild type, La ). LaR promastigotes were cross-resistant to other DNA topoisomerase I inhibitors (camptothecin) and more susceptible to anti-leishmanial drugs pentamidine and miltefosine. A protective effect on cell viability was observed by pretreating the parasite with Ca 2+ channel blockers followed by CP2 in La but not in LaR . Analyses of the cell viability of La and LaR using electron transport chain (ETC) inhibitors demonstrated that La is more sensitive than LaR . The studies of mitochondrial oxygen consumption demonstrated that LaR is less susceptible to complex III (ubiquinol-cytochrome c reductase – CcR) inhibitor, antimycin A (AA). CcR activities of La and LaR were equal for both strains in the absence of CP2 and significantly decreased, 69 % for La and 51 % for LaR , in the presence of CP2 . This resistance is attributed to overexpression of CcR, confirmed by the RT-qPCR. CcR inhibition by CP2 leads the parasite to increase the reactive oxygen species (ROS) production, principally in La. Therefore, in this work, we suggested that CcR is the main target of CP2 in the mitochondria, acting to inhibit mitochondria respiratory, and the LaR mutant has increased activity of CcR, which reduces the formation of ROS. • [Pd(dmba)(μ-N 3 )] 2 ( CP2 ) had been an alternative to outline the appearance of chemoresistance against L. amazonensis. • Cytochrome c reductase is the main target of CP2 in the mitochondria of the Leishmania parasites. • Resistance of L. amazonensis to CP2 is not associated with increased drug efflux but attributed to complex III overexpression. • CP2 -resistant L. amazonensis is deficient in mitochondrial Ca 2+ uptake and develops a protective effect from oxidative stress.
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: gold
Estimated APC paid: $2,700
Funders: Rutgers, The State University of New Jersey, Fundação de Amparo à Pesquisa do Estado de São Paulo, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Financiadora de Estudos e Projetos, Universidade Estadual Paulista, National Institutes of Health, National Institute of Allergy and Infectious Diseases
Awards: G1183939403, G1291480379, G2117669404, G295657101, G3524400595, Improving antimicrobial photodynamic therapy for infectious disease associating peptide aurein 1.2, CMV Vectored Herpes Simplex Vaccine, G4267633134, Antimicrobial photodynamic therapy by continuous and switched mode irradiation against Enterococcus faecalis and Cutibacterium acnes, G5067324287, G6596168048, Therapeutics for leishmaniasis: from screening to the study of mechanisms of action, a contribution to the discovery of new antileishmanial molecules, G7131723528
OpenAlex ID: W4405586275