Article

Phospholipase C-ζ-induced Ca2+ oscillations cause coincident cytoplasmic movements in human oocytes that failed to fertilize after intracytoplasmic sperm injection

School of Medicine, Cardiff University, Heath Park, Cardiff, United Kingdom.
Fertility and sterility (Impact Factor: 4.59). 01/2012; 97(3):742-7. DOI: 10.1016/j.fertnstert.2011.12.013
Source: PubMed

ABSTRACT

To evaluate the imaging of cytoplasmic movements in human oocytes as a potential method to monitor the pattern of Ca(2+) oscillations during activation.
Test of a laboratory technique.
University medical school research laboratory.
Donated unfertilized human oocytes from intracytoplasmic sperm injection (ICSI) cycles.
Microinjection of oocytes with phospholipase C (PLC) zeta (ζ) cRNA and a Ca(2+)-sensitive fluorescent dye.
Simultaneous detection of oocyte cytoplasmic movements using particle image velocimetry (PIV) and of Ca(2+) oscillations using a Ca(2+)-sensitive fluorescent dye.
Microinjection of PLCζ cRNA into human oocytes that had failed to fertilize after ICSI resulted in the appearance of prolonged Ca(2+) oscillations. Each transient Ca(2+) concentration change was accompanied by a small coordinated movement of the cytoplasm that could be detected using PIV analysis.
The occurrence and frequency of cytoplasmic Ca(2+) oscillations, a critical parameter in activating human zygotes, can be monitored by PIV analysis of cytoplasmic movements. This simple method provides a novel, noninvasive approach to determine in real time the occurrence and frequency of Ca(2+) oscillations in human zygotes.

Download full-text

Full-text

Available from: Michail Nomikos
  • Source
    • ") . Such cytoplasmic flows have also been described in human 1 - cell embryos ( Swann et al . , 2012 ) , although there are still no data correlating cytoplasmic dynamics with developmental quality of the human embryos ."
    [Show abstract] [Hide abstract]
    ABSTRACT: Cleavage is a period after fertilization, when a 1-cell embryo starts developing into a multicellular organism. Due to a series of mitotic divisions, the large volume of a fertilized egg is divided into numerous smaller, nucleated cells—blastomeres. Embryos of different phyla divide according to different patterns, but molecular mechanism of these early divisions remains surprisingly conserved. In the present paper, we describe how polarity cues, cytoskeleton and cell-to-cell communication interact with each other to regulate orientation of the early embryonic division planes in model animals such as Caenorhabditis elegans, Drosophila and mouse. We focus particularly on the Par pathway and the actin-driven cytoplasmic flows that accompany it. We also describe a unique interplay between Par proteins and the Hippo pathway in cleavage mammalian embryos. Moreover, we discuss the potential meaning of polarity, cytoplasmic dynamics and cell-to-cell communication as quality biomarkers of human embryos.
    Preview · Article · Dec 2015 · Molecular Human Reproduction
    • "This pattern of localization supports the role of PLCz as the SOAF, since after the acrosome reaction, the equatorial region of the sperm membrane is exposed, adheres to and fuses with the oolemma (Barroso et al., 2009). In strong support of the role of PLCz, is the fact that mammalian oocytes can be activated following microinjection of either recombinant PLCz or complementary RNA (cRNA) encoding PLCz (Yoon et al., 2008; Swann et al., 2012; Nomikos et al., 2013b). "
    [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND Infertility affects between 10 and 16% of couples worldwide. Twenty to 30% of cases of infertility are due to a male factor, 20–35% to a female factor, and 25–40% are due to both male and female factors. In ∼10–25% of cases, the precise underlying cause remains unclear. IVF or ICSI followed by embryo transfer can be very appropriate treatment options in cases of female tubal damage, ovulatory failure or male-factor infertility. While the use of IVF has been reported to be suitable for many infertile couples, normal IVF cycles can fail in some cases. While ICSI can represent a powerful alternative in cases of IVF failure, complete fertilization failure can still occur in 1–5% of ICSI cycles. This can be due to a variety of factors and while commonly attributed to deficiency of sperm factors, it is very likely that abnormalities in crucial oocyte factors could also play a key role.
    No preview · Article · Sep 2015 · Human Reproduction Update
  • Source
    • "Another study showed that the microinjection of oocyte activation deficient spermatozoa along with exposure to calcium ionophore generated live offspring [133]. Furthermore, microinjection of oocytes, that failed to fertilize with ICSI, with PLC␨ cRNA resulted in the appearance of prolonged Ca 2+ oscillations where each transient Ca 2+ wave was accompanied by a small coordinated cytoplasmic movement [172]. These studies further solidified the idea that PLC␨ is a great candidate as a clinical therapeutic solution that could avoid potentially deleterious effects associated with AOA, which use the non-physiological stimuli. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Since the establishment of in vitro fertilization, it became evident that almost half of the couples failed to achieve fertilization and this phenomenon was attributed to a male gamete dysfunction. The adoption of assisted fertilization techniques particularly ICSI has been able to alleviate male factor infertility by granting the consistent ability of a viable spermatozoon to activate an oocyte. Single sperm injection, by pinpointing the beginning of fertilization, has been an invaluable tool in clarifying the different aspects of early fertilization and syngamy. However, even with ICSI some couples fail to fertilize due to ooplasmic dysmaturity in relation to the achieved nuclear maturation marked by the extrusion of the first polar body. More uncommon are cases where the spermatozoa partially or completely lack the specific oocyte activating factor. In this work, we review the most relevant aspects of fertilization and its failure through assisted reproductive technologies. Attempts at diagnosing and treating clinical fertilization failure are described.
    Full-text · Article · Nov 2013 · Cell calcium
Show more