Oligomycin A-induced inhibition of mitochondrial ATP-synthase activity suppresses boar sperm motility and in vitro capacitation achievement without modifying overall sperm energy levels

Abstract

Incubation of boar spermatozoa in a capacitation medium with oligomycin A, a specific inhibitor of the F0 component of the mitochondrial ATP synthase, induced an immediate and almost complete immobilisation of cells. Oligomycin A also inhibited the ability of spermatozoa to achieve feasible in vitro capacitation (IVC), as measured through IVC-compatible changes in motility patterns, tyrosine phosphorylation levels of the acrosomal p32 protein, membrane fluidity and the ability of spermatozoa to achieve subsequent, progesterone-induced in vitro acrosome exocytosis (IVAE). Both inhibitory effects were caused without changes in the rhythm of O2 consumption, intracellular ATP levels or mitochondrial membrane potential (MMP). IVAE was accompanied by a fast and intense peak in O2 consumption and ATP levels in control spermatozoa. Oligomycin A also inhibited progesterone-induced IVAE as well as the concomitant peaks of O2 consumption and ATP levels. The effect of oligomycin on IVAE was also accompanied by concomitant alterations in the IVAE-induced changes on intracellular Ca2+ levels and MMP. Our results suggest that the oligomycin A-sensitive mitochondrial ATP-synthase activity is instrumental in the achievement of an adequate boar sperm motion pattern, IVC and IVAE. However, this effect seems not to be linked to changes in the overall maintenance of adequate energy levels in stages other than IVAE.

Label-free protein quantification in freshly ejaculated versus post-mating spermatophores of the noble crayfish Astacus astacus

“…Experimental inhibition of mitochondrial ATP synthase activity suppresses capacitation achievement in the boar spermatozoon [30]. The upregulation of these proteins in the post-mating crayfish spermatophore could be attributed to the elevation of energy demand for protein synthesis, post-translational modifications, ion transport, and other processes necessary for final maturation and capacitation of spermatozoa.…”

Current knowledge on boar sperm metabolism: Comparison with other mammalian species

“…This clearly indicates that the induction of a feasible IVAE is concomitant with a sudden activation of the mitochondrial energysynthesizing processes. Furthermore, the inhibition of the mitochondrial ATP synthase by incubation with the specific inhibitor, oligomycin A, inhibits not only the IVAE-related peak of mitochondrial energy production but also motility and the whole achievement of a feasible "in vitro" capacitation (IVC; See [55].) Remarkably, these effects are induced without significant changes in the overall ATP levels [55].…”

“…These surprising results could lead us to think that other mitochondrial functions that are concomitant to energy production could be related to the boar sperm mitochondrial-linked control of motility, IVC, and IVAE. Thus, the IVC-linked increase in the tyrosine phosphorylation levels of the p32 protein, which is a classic sign of the achievement of boar sperm IVC, is prevented by the presence of oligomycin A [55]. This seems to indicate the existence of a direct link between the ATP The serine phosphorylation levels of each spot in the miniarrays were then analyzed.…”

“…Furthermore, the inhibition of the mitochondrial ATP synthase by incubation with the specific inhibitor, oligomycin A, inhibits not only the IVAE-related peak of mitochondrial energy production but also motility and the whole achievement of a feasible "in vitro" capacitation (IVC; See [55].) Remarkably, these effects are induced without significant changes in the overall ATP levels [55]. This indicates that although the ATP synthesized in mitochondria is only a very low percentage of the total ATP production of boar spermatozoa, this small fraction is instrumental in the achievement of very important features of boar sperm function, such as maintenance of motility and the achievement of both IVC and subsequent progesterone-induced IVAE.…”

Sperm Membrane Channels, Receptors and Kinematics : Using boar spermatozoa for drug toxicity screening

“…The divalent cation Ca 2+ will activate a series of intracellular pathways mainly leading to hyperactivation and, in contact with the ZP, to AR (Darszon et al 2006). The flux through the sperm plasma membrane and hence the intracellular concentration of Ca 2+ is finely regulated (Darszon et al 2006;Yeste et al 2014). The bicarbonate concentration in SP is 10-fold higher than in the cauda (Rodríguez-Martínez et al 1990a), the molecule being primarily responsible for the activation of sperm motility (Okamura et al 1985).…”