Expression of Hsp60 and Grp78 in the human endometrium and oviduct, and their effect on sperm functions.
BACKGROUND
Within the female genital tract, spermatozoa undergo a series of membranous and intracellular transformations to become competent at fertilizing the oocyte. In the bovine, previous studies have shown that two oviductal proteins, heat shock protein 60 (Hsp60) and glucose regulated protein 78 (Grp78), bind to spermatozoa and may be involved in this acquisition of fertilizing competence.


METHODS
Immunohistochemical studies were performed on human endometrial and oviduct tissues to localize these two chaperones in the female genital tract. Human spermatozoa were incubated under capacitating conditions in the presence or absence of recombinant Hsp60 or Grp78. Following a 4-h incubation, the effects of these proteins were evaluated on sperm acrosomal integrity, motility, protein phosphotyrosine content and free intracellular calcium concentrations.


RESULTS
Both chaperones were present in the uterus and oviduct epithelial cells and were shown to bind to human spermatozoa. Incubation with either exogenous Hsp60 or Grp78 did not affect sperm viability, motility or acrosomal integrity. Hsp60 partially prevented the increase in p81 phosphotyrosine content induced by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine and both chaperones significantly increased the sperm intracellular calcium concentration. Moreover, the progesterone-induced increase in intracellular calcium was higher when sperm were pre-treated with either Hsp60 or Grp78.


CONCLUSIONS
Our study suggests that these two proteins may affect human sperm intracellular signalling pathways and capacitation.
Lachance
Catherine
C
Département d'Obstétrique et de Gynécologie, Centre de Recherche en Biologie de la Reproduction, Université Laval, Unité de Recherche en Ontogénie et Reproduction, Centre de recherche du CHUQ (CHUL), T1-49, 2705 boul. Laurier, Québec, QC, Canada G1V 4G2.
Bailey
Janice L
JL
Leclerc
Pierre
P
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D020101:Acrosome Reaction / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D018834:Chaperonin 60 / Q000096:biosynthesis* / Q000378:metabolism; D004717:Endometrium / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D005187:Fallopian Tubes / Q000378:metabolism*; D005260:Female; D006360:Heat-Shock Proteins / Q000096:biosynthesis* / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D018832:Molecular Chaperones / Q000096:biosynthesis* / Q000378:metabolism; D019000:Phosphotyrosine / Q000096:biosynthesis; D011374:Progesterone / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D013081:Sperm Motility / Q000187:drug effects; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*; D019284:Thapsigargin / Q000494:pharmacology
D018834:Chaperonin 60; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D011994:Recombinant Proteins; D019000:Phosphotyrosine; D011374:Progesterone; D019284:Thapsigargin; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine