The effects of antibodies to heat shock protein 70 in fertilization and embryo development

Abstract

The role of heat shock proteins in shielding organisms from environmental stress is illustrated by the large-scale synthesis of these proteins by the organisms studied to date. However, recent evidence also suggests an important role for heat shock proteins in fertilization and early development of mammalian embryos. We found that the presence of anti-HSP70 antibody significantly reduced tight binding of spermatozoa to the zona pellucida of bovine oocytes and interrupted completion of meiosis II and pronuclear formation. Furthermore, the presence of anti-HSP70 in culture medium from day 3 to day 9 of development increased apoptosis and significantly reduced the number of embryos reaching the blastocyst stage. We further observed that the proportion of apoptotic cells in bovine blastocysts was significantly lower after in-vitro culture with a prior exposure to increased temperature. However, nuclear localization of the p53 protein, which is thought to be essential for the up-regulation of genes involved in apoptosis and cell cycle arrest, was detected in the majority of nuclei in blastocysts exposed to increased temperature, whereas in their untreated (control) counterparts, p53 protein was only detected in the cytoplasm. The decrease in apoptosis after exposure of blastocysts to increased temperature may be attributed to cell cycle arrest resulting from nuclear localization of the p53 protein and/or to an increase in heat shock protein synthesis. We propose that HSP70 plays a critical role in fertilization and early embryonic development.

Increased apoptosis in bovine blastocysts exposed to high levels of IGF1 is not associated with downregulation of the IGF1 receptor

“…This positive effect of IGF1 at physiological concentrations is probably related to improved glucose uptake via its own receptor (Pantaleon & Kaye 1996) and could be due in part to a better modulation of IGF1 binding via higher expression of IGBPB3 observed in this and other studies (Prelle et al 2001, Block et al 2008. The lower protein expression of TP53 in the supraphysiological IGF1 group was rather surprising since activation of TP53 is considered indicative of embryonic demise (Keim et al 2001, Matwee et al 2001. However, recent data suggest that TP53 does not act merely as a death signal, but rather as a modulator of damage responses to ensure successful development (Toyoshima 2009).…”

Hyaluronan and hyaluronidase, which is better for embryo development?

“…It is also an active component of the ewe oviduct that is required for maintenance of sperm viability (Lloyd, et al 2009). The presence of anti-HSP70 in culture medium from day 3 to day 9 of development increased apoptosis in bovine embryos and significantly reduced the number of embryos reaching the blastocyst stage (Matwee, et al 2001) illustrating its importance during this period. Therefore, the increased HSP70 expression in ovine oviducts as reported in the present study may mediate its positive effects on blastocyst rate and increased cell numbers.…”

Expressions of miR-15a and its target gene HSPA1B in the spermatozoa of patients with varicocele

“…The stage-specific expression pattern displayed by HSPs during spermatogenesis indicates that HSPs are involved in germ cell development (Feng et al 2001, Huo et al 2004, Asquith et al 2005, Terada et al 2005, Held et al 2006, Adly et al 2008, Walsh et al 2008, Lachance et al 2010, Ji et al 2012. In addition, HSPA1B has been implicated in fertilization and embryo development (Neuer et al 2000, Matwee et al 2001. It can protect embryos from hyperthermia-induced congenital defects, possibly through reducing hyperthermia-induced apoptosis (Barrier et al 2009).…”