Mitochondrial oxidative phosphorylation machinery (OXPHOS) (OXPHOS)

The mitochondrial oxidative phosphorylation (OXPHOS) machinery in parasitic helminths is a vital system for energy generation, specifically adapted to the hypoxic environments of the host's body (Amino et al., 2005). While mammalian mitochondria primarily perform aerobic respiration, many helminths utilize a unique anaerobic pathway involving rhodoquinone and fumarate reductase (FRD) to maintain energy production (Kita et al., 2007). This specialized machinery, particularly Complex II acting as FRD, is a primary target for several classes of anthelmintic drugs (Mogi et al., 2009). For instance, salicylanilides like niclosamide act as uncouplers that dissipate the mitochondrial proton gradient, while other agents inhibit electron transport or specific enzymatic activities within the chain (Wojtkowiak et al., 2013). Because these anaerobic pathways are absent or significantly different in human hosts, they provide a high degree of selective toxicity. Disrupting the OXPHOS machinery leads to a rapid depletion of cellular ATP, resulting in the paralysis and eventual death of the parasite. Consequently, this system remains a cornerstone for developing treatments against various helminthic infections, including ascariasis and fascioliasis.

Other names

Mitochondrial respiratory chainElectron transport chainFumarate respiration systemHelminth mitochondrial respiratory system

Inhibition of fumarate reductase activity, uncoupling of oxidative phosphorylation by dissipating the mitochondrial proton gradient, and inhibition of electron transport through the respiratory chain complexes (Amino et al., 2005; Mogi et al., 2009).