TY - JOUR
T1 - Mitochondrial complex III in larval stage of Echinococcus multilocularis as a potential chemotherapeutic target and in vivo efficacy of atovaquone against primary hydatid cysts
AU - Enkai, Shigehiro
AU - Inaoka, Daniel Ken
AU - Kouguchi, Hirokazu
AU - Irie, Takao
AU - Yagi, Kinpei
AU - Kita, Kiyoshi
N1 - Publisher Copyright:
© 2019 The Authors
PY - 2020/4
Y1 - 2020/4
N2 - Echinococcus multilocularis employs aerobic and anaerobic respiration pathways for its survival in the specialized environment of the host. Under anaerobic conditions, fumarate respiration has been identified as a promising target for drug development against E. multilocularis larvae, although the relevance of oxidative phosphorylation in its survival remains unclear. Here, we focused on the inhibition of mitochondrial cytochrome bc1 complex (complex III) and evaluated aerobic respiratory activity using mitochondrial fractions from E. multilocularis protoscoleces. An enzymatic assay revealed that the mitochondrial fractions possessed NADH-cytochrome c reductase (mitochondrial complexes I and III) and succinate-cytochrome c reductase (mitochondrial complexes II and III) activities in the aerobic pathway. Enzymatic analysis showed that atovaquone, a commercially available anti-malarial drug, inhibited mitochondrial complex III at 1.5 nM (IC50). In addition, culture experiments revealed the ability of atovaquone to kill protoscoleces under aerobic conditions, but not under anaerobic conditions, indicating that protoscoleces altered their respiration system to oxidative phosphorylation or fumarate respiration depending on the oxygen supply. Furthermore, combined administration of atovaquone with atpenin A5, a quinone binding site inhibitor of complex II, completely killed protoscoleces in the culture. Thus, inhibition of both complex II and complex III was essential for strong antiparasitic effect on E. multilocularis. Additionally, we demonstrated that oral administration of atovaquone significantly reduced primary alveolar hydatid cyst development in the mouse liver, compared with the untreated control, indicating that complex III is a promising target for development of anti-echinococcal drug.
AB - Echinococcus multilocularis employs aerobic and anaerobic respiration pathways for its survival in the specialized environment of the host. Under anaerobic conditions, fumarate respiration has been identified as a promising target for drug development against E. multilocularis larvae, although the relevance of oxidative phosphorylation in its survival remains unclear. Here, we focused on the inhibition of mitochondrial cytochrome bc1 complex (complex III) and evaluated aerobic respiratory activity using mitochondrial fractions from E. multilocularis protoscoleces. An enzymatic assay revealed that the mitochondrial fractions possessed NADH-cytochrome c reductase (mitochondrial complexes I and III) and succinate-cytochrome c reductase (mitochondrial complexes II and III) activities in the aerobic pathway. Enzymatic analysis showed that atovaquone, a commercially available anti-malarial drug, inhibited mitochondrial complex III at 1.5 nM (IC50). In addition, culture experiments revealed the ability of atovaquone to kill protoscoleces under aerobic conditions, but not under anaerobic conditions, indicating that protoscoleces altered their respiration system to oxidative phosphorylation or fumarate respiration depending on the oxygen supply. Furthermore, combined administration of atovaquone with atpenin A5, a quinone binding site inhibitor of complex II, completely killed protoscoleces in the culture. Thus, inhibition of both complex II and complex III was essential for strong antiparasitic effect on E. multilocularis. Additionally, we demonstrated that oral administration of atovaquone significantly reduced primary alveolar hydatid cyst development in the mouse liver, compared with the untreated control, indicating that complex III is a promising target for development of anti-echinococcal drug.
KW - Atovaquone
KW - Drug target
KW - Echinococcus multilocularis
KW - Fumarate respiration
KW - Mitochondrial complex III
KW - Oxidative phosphorylation
UR - http://www.scopus.com/inward/record.url?scp=85074715242&partnerID=8YFLogxK
U2 - 10.1016/j.parint.2019.102004
DO - 10.1016/j.parint.2019.102004
M3 - 記事
C2 - 31678356
AN - SCOPUS:85074715242
SN - 1383-5769
VL - 75
JO - Parasitology International
JF - Parasitology International
M1 - 102004
ER -