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Pablo E. Visconti

Professor

Research areas include mammalian sperm are not able to fertilize eggs immediately after ejaculation. They acquire fertilization capacity after residing in the female tract for a finite period of time in a process known as capacitation. Our research focused on the study of sperm signaling pathways and how they regulate the sperm ability to fertilize. As part of our investigations, we have shown that capacitation is associated with the activation of protein kinase A upstream the stimulation of protein tyrosine phosphorylation. We have conducted phosphoproteomic identification of those sequences phosphorylated during capacitation. Also, our laboratory studies other signal transduction events in sperm. Among them, we evaluate changes in sperm lipids, in the sperm membrane potential, in the intracellular pH and in intracellular calcium. As part of our interest in phosphorylation pathways, we investigate protein kinases exclusively expressed in testicular germ cells and in the sperm. These kinases are essential for spermiogenesis and we hypothesized that they are targets for male contraception.

Current Research
We have recently found that increasing intracellular Ca2+ is sufficient to render the sperm fertile even when other signaling pathways such as the activation of protein kinase A or tyrosine phosphorylation are blocked. This research might be used translationally to improve in vitro fertilization protocols in humans and other species. Also at the translational level, considering that in the absence of testis-specific kinases, mice are sterile, we are conducting the search for specific inhibitors to be used as male contraceptives. At the basic levels, our laboratory is currently evaluating signaling pathways downstream the increase in intracellular Ca2+. Also, we continued with our research on phosphorylation pathways and we are currently investigating how ser/thr phosphatases are regulated as part of the acquisition of the sperm ability to fertilize.

Learn more at www.vasci.umass.edu/research-faculty/pablo-e-visconti

Academic Background:

  • PhD University of Buenos Aires, Argentina
  • Postdoctoral Training: University of Pennsylvania, Philadelphia
1: Sánchez-Cárdenas C, Montoya F, Navarrete FA, Hernández-Cruz A, Corkidi G, Visconti PE, Darszon A. Intracellular Ca2+ threshold reversibly switches flagellar beat off and on. Biol Reprod. 2018 Jun 8. doi: 10.1093/biolre/ioy132. [Epub ahead of print] PubMed PMID: 29893793.
2: Gervasi MG, Xu X, Carbajal-Gonzalez B, Buffone MG, Visconti PE, Krapf D. The actin cytoskeleton of the mouse sperm flagellum is organized in a helical structure. J Cell Sci. 2018 Jun 11;131(11). pii: jcs215897. doi: 10.1242/jcs.215897. PubMed PMID: 29739876.
3: Gervasi MG, Visconti PE. Molecular changes and signaling events occurring in spermatozoa during epididymal maturation. Andrology. 2017 Mar;5(2):204-218. doi: 10.1111/andr.12320. Review. PubMed PMID: 28297559; PubMed Central PMCID: PMC5354101.
4: Gervasi MG, Visconti PE. Chang's meaning of capacitation: A molecular perspective. Mol Reprod Dev. 2016 Oct;83(10):860-874. doi: 10.1002/mrd.22663. Review. PubMed PMID: 27256723.
5: Navarrete FA, Alvau A, Lee HC, Levin LR, Buck J, Leon PM, Santi CM, Krapf D, Mager J, Fissore RA, Salicioni AM, Darszon A, Visconti PE. Transient exposure to calcium ionophore enables in vitro fertilization in sterile mouse models. Sci Rep. 2016 Sep 15;6:33589. doi: 10.1038/srep33589. PubMed PMID: 27627854; PubMed Central PMCID: PMC5024339.
 
Contact Info

Department of Veterinary and Animal Sciences
ISB 647 W
North Pleasant Street
Amherst, MA 01003-9292

(413) 545-5565
pvisconti@vasci.umass.edu

www.vasci.umass.edu/research-faculty/pablo-e-visconti