Nitao, Elis Torrezan Goncalves Ramalho ORCID: 0000-0002-1841-7694 (2019). Progesterone-induced [ca2+]i oscillations and regulation of human sperm behaviour. University of Birmingham. Ph.D.
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Nitao2019PhD.pdf
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Abstract
Ca2+ signalling is crucial to modulate sperm motility and changes in the intracellular calcium concentration [Ca2+]i may underlie ‘switching’ of sperm swimming behaviour in human spermatozoa, which is important for sperm progression in the female tract. I investigated the mechanism by which progesterone induces [Ca2+]i oscillations and also investigated the role of [Ca2+]i oscillations for sperm swimming behaviour and penetration ability into mucus. Sperm were loaded with Ca2+-indicator fluo4/AM, treated with different agonists and analysed in single live-cell imaging and functional assays were also performed in free-swimming sperm. Approximately 25% of the human sperm population exhibit [Ca2+]i oscillations, independently of sperm capacitation. [Ca2+]i rise first in flagellum then spread actively to the head, apparently triggering CICR. Membrane potential (Vm), Slo3 channels and CatSper channels contribute to [Ca2+]i oscillations generation. [Ca2+]i oscillations occur in free-swimming spermatozoa and are associated with switching of sperm swimming behaviour in both low and high viscosity environments: drives velocity, sperm turning, hyperactivated motility and regulates attachment/detachment from substrate. Consistent with the involvement of CatSper in generation of [Ca2+]i oscillations, regulation of sperm swimming velocity and cell progression are dependent on CatSper channels. Additionally, sperm ability to penetrate into mucus environment is also dependent on CatSper activity.
Type of Work: | Thesis (Doctorates > Ph.D.) | |||||||||
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Award Type: | Doctorates > Ph.D. | |||||||||
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Licence: | All rights reserved | |||||||||
College/Faculty: | Colleges (2008 onwards) > College of Life & Environmental Sciences | |||||||||
School or Department: | School of Biosciences | |||||||||
Funders: | Other | |||||||||
Other Funders: | CAPES Foundation (Ministry of Education of Brazil) | |||||||||
Subjects: | Q Science > Q Science (General) Q Science > QP Physiology |
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URI: | http://etheses.bham.ac.uk/id/eprint/9261 |
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