CHARACTERIZATION OF MITOCHONDRIAL ACTIVITY DURING MURINE SPERM CAPACITATION

CUASNICU P S; GIACCAGLI MM; COHEN DJ; GOMEZ ELIAS M; DA ROS VG

Congreso; Reunión anual de Sociedades de Biociencias.; 2019

CHARACTERIZATION OF MITOCHONDRIAL ACTIVITY DURING MURINE SPERM CAPACITATIONMilagros GIACCAGLI | Matías GOMEZ ELIAS | Patricia Sara CUASNICU | Debora Juana COHEN | Vanina Gabriela DA ROS INSTITUTO DE BIOLOGÍA Y MEDICINA EXPERIMENTAL (IBYME)Mammalian sperm need undergo a capacitation process in the female reproductive tract to acquire the ability to fertilize an egg. Overall, capacitation involves a series of structural and functional changes in sperm including membrane modifications, modulation of enzyme activities and protein phosphorylation. All these changes require an adequate supply of energy and, therefore, imply a fine energy administration. However, the energy sources and the molecular mechanisms of this regulation are still poorly understood. Based on this, the aim of this study was to determine the relevance of mitochondrial activity on mouse sperm capacitation. For this purpose, changes in mitochondrial membrane potential (MMP) were measured in live sperm during capacitation by flow cytometry using the probe TMRE. Results showed that only live sperm exhibited high MMP and, moreover, the percentage of sperm with high MMP increased during capacitation. When sperm were treated with increasing concentrations of the mitochondrial uncoupler CCCP during capacitation, there was a decrease in the percentage of cells with high MMP with no effects on sperm viability. Interestingly, we also observed a decrease in the average fluorescence intensity of sperm with high MMP compared to the control group. Next, we evaluated the need of capacitation for MMP increase by inhibiting the activity of PKA, a signaling molecule critical for this process. We observed that the percentage of sperm with high MMP did not increase in the presence of the PKA inhibitor H89. We next evaluated motility and MMP by fluorescence microscopy and observed that whereas motile sperm exhibited high MMP, cells with low MMP were immotile. In addition, treatment with CCCP produced a decrease in motility. In summary, we show, for the first time, that MMP increases during mouse sperm capacitation and that mitochondrial activity could be associated with the maintenance of sperm motility during this process.