Abstract:HSP90 levels are downregulated in oligoasthenozoospermia, and its functional inhibition attenuates progesterone-mediated sperm motility and acrosome reaction.
“…As a consequence of a higher cleavage rate, a 12% increase in the number of >8 cell-embryos at Day 4 and an 8% increase in blastocyst rates were observed (GLM, p = 0.027 and p = 0.014, respectively). Cat oviductal exosomes contain proteins known to be important for fertilization, such as OVGP1 (improves sperm viability and motility in vitro ) 65 , CD9, TCP1, CCT3, CCT4, CCT7, CCT8, (important for sperm-oocyte binding) 72,73 , HSP70 (improves sperm survival in vitro ) 74 and HSP90 (mediates sperm hyperactivation and acrosome exocytosis) 21,75 . The transfer of these proteins from the oviductal EVs to the spermatozoa could explain the increased fertilization rates observed.Figure 6Effect of sperm incubation with (Sperm + EVs) or without (Sperm) oviductal extracellular vesicles (EVs) on fertilization rate (cleavage), percentage of embryos of 8 or more cells (>8-cells) and blastocyst rate (blastocyst).…”
Fertilization and early embryo development are regulated by a unique maternal-gamete/embryo cross-talk within the oviduct. Recent studies have shown that extracellular vesicles (EVs) within the oviduct play important roles in mediating this developmental process. Here, we examined the influence of oviductal EVs on sperm function in the domestic cat. We demonstrated that (1) EVs are enriched in proteins related to energy metabolism, membrane modification, and reproductive function; (2) EVs bound and fused with the membranes of the acrosome and mid piece; and (3) incubating sperm with EVs improved motility, fertilizing capacity of cat spermatozoa and prevented acrosomal exocytosis
in vitro
. These findings indicated that oviductal EVs mediate sperm function and fertilization in the cat and provides new insights to improve sperm cryopreservation and
in vitro
fertilization in the domestic and wild felids and human.
“…As a consequence of a higher cleavage rate, a 12% increase in the number of >8 cell-embryos at Day 4 and an 8% increase in blastocyst rates were observed (GLM, p = 0.027 and p = 0.014, respectively). Cat oviductal exosomes contain proteins known to be important for fertilization, such as OVGP1 (improves sperm viability and motility in vitro ) 65 , CD9, TCP1, CCT3, CCT4, CCT7, CCT8, (important for sperm-oocyte binding) 72,73 , HSP70 (improves sperm survival in vitro ) 74 and HSP90 (mediates sperm hyperactivation and acrosome exocytosis) 21,75 . The transfer of these proteins from the oviductal EVs to the spermatozoa could explain the increased fertilization rates observed.Figure 6Effect of sperm incubation with (Sperm + EVs) or without (Sperm) oviductal extracellular vesicles (EVs) on fertilization rate (cleavage), percentage of embryos of 8 or more cells (>8-cells) and blastocyst rate (blastocyst).…”
Fertilization and early embryo development are regulated by a unique maternal-gamete/embryo cross-talk within the oviduct. Recent studies have shown that extracellular vesicles (EVs) within the oviduct play important roles in mediating this developmental process. Here, we examined the influence of oviductal EVs on sperm function in the domestic cat. We demonstrated that (1) EVs are enriched in proteins related to energy metabolism, membrane modification, and reproductive function; (2) EVs bound and fused with the membranes of the acrosome and mid piece; and (3) incubating sperm with EVs improved motility, fertilizing capacity of cat spermatozoa and prevented acrosomal exocytosis
in vitro
. These findings indicated that oviductal EVs mediate sperm function and fertilization in the cat and provides new insights to improve sperm cryopreservation and
in vitro
fertilization in the domestic and wild felids and human.
“…Geldanamycin is a specific Hsp90 inhibitor that has been shown to interrupt human sperm capacitation, change protein tyrosine phosphorylation levels, and decrease hyperactivated motility and acrosome reaction. In addition, other studies have found that Hsp90 levels are downregulated in oligoasthenozoospermia and that the functional inhibition of Hsp90 can attenuate progesterone-mediated sperm motility and acrosome reaction [12,13]. However, the underlying mechanisms remain unknown.…”
Background
Heat shock protein 90 (Hsp90) is a highly abundant eukaryotic molecular chaperone that plays important roles in client protein maturation, protein folding and degradation, and signal transduction. Previously, we found that both Hsp90 and its co-chaperone cell division cycle protein 37 (Cdc37) were expressed in human sperm. Hsp90 is known to be involved in human sperm capacitation via unknown underlying mechanism(s). As Cdc37 was a kinase-specific co-chaperone of Hsp90, Hsp90 may regulate human sperm capacitation via other kinases. It has been reported that two major mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase 1/2 (Erk1/2) and p38, are expressed in human sperm in the same locations as Hsp90 and Cdc37. Phosphorylated Erk1/2 has been shown to promote sperm hyperactivated motility and acrosome reaction, while phosphorylated p38 inhibits sperm motility. Therefore, in this study we explored whether Hsp90 modulates human sperm capacitation via the Erk1/2 and p38 MAPK signaling pathways.
Methods
Human sperm was treated with the Hsp90-specific inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) during capacitation. Computer-assisted sperm analyzer (CASA) was used to detect sperm motility and hyperactivation. The sperm acrosome reaction was analyzed by using fluorescein isothiocyanate-conjugated Pisum sativum agglutinin (PSA-FITC) staining. The interactions between Hsp90, Cdc37, Erk1/2 and p38 were assessed using co-immunoprecipitation (Co-IP) experiments. Western blotting analysis was used to evaluate the levels of protein expression and phosphorylation.
Results
Human sperm hyperactivation and acrosome reaction were inhibited by 17-AAG, suggesting that Hsp90 is involved in human sperm capacitation. In addition, Co-IP experiments revealed that 17-AAG reduced the interaction between Hsp90 and Cdc37, leading to the dissociation of Erk1/2 from the Hsp90-Cdc37 protein complex. Western blotting analysis revealed that levels of Erk1/2 and its phosphorylated form were subsequently decreased. Decreasing of Hsp90-Cdc37 complex also affected the interaction between Hsp90 and p38. Nevertheless, p38 dissociated from the Hsp90 protein complex and was activated by autophosphorylation.
Conclusions
Taken together, our findings indicate that Hsp90 is involved in human sperm hyperactivation and acrosome reaction. In particular, Hsp90 and its co-chaperone Cdc37 form a protein complex with Erk1/2 and p38 to regulate their kinase activity. These results suggest that Hsp90 regulates human sperm capacitation via the Erk1/2 and p38 MAPK signaling pathways.
“…Geldanamycin is a speci c Hsp90 inhibitor that has been shown to interrupt human sperm capacitation, change protein tyrosine phosphorylation levels, and decrease hyperactivated motility and acrosome reaction. In addition, other studies have found that Hsp90 levels are downregulated in oligoasthenozoospermia and that the functional inhibition of Hsp90 can attenuate progesterone-mediated sperm motility and acrosome reaction (12,13). However, the underlying mechanisms remain unknown.…”
Background: Heat shock protein 90 (Hsp90) is a highly abundant eukaryotic molecular chaperone that plays important roles in client protein maturation, protein folding and degradation, and signal transduction. Previously, we found that both Hsp90 and its co-chaperone cell division cycle protein 37 (Cdc37) were expressed in human sperm. Hsp90 is known to be involved in human sperm capacitation via unknown underlying mechanism(s). As Cdc37 was a kinase-specific co-chaperone of Hsp90, Hsp90 may regulate human sperm capacitation via other kinases. It has been reported that two major mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase 1/2 (Erk1/2) and p38, are expressed in human sperm in the same locations as Hsp90 and Cdc37. Phosphorylated Erk1/2 has been shown to promote sperm hyperactivated motility and acrosome reaction, while phosphorylated p38 inhibits sperm motility. Therefore, in this study we explored whether Hsp90 modulates human sperm capacitation via the Erk1/2 and p38 MAPK signaling pathways. Methods: Human sperm was treated with the Hsp90-specific inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) during capacitation. Computer-assisted sperm analyzer (CASA) was used to detect sperm motility and hyperactivation. The sperm acrosome reaction was analyzed by using fluorescein isothiocyanate-conjugated Pisum sativum agglutinin (PSA-FITC) staining. The interactions between Hsp90, Cdc37, Erk1/2 and p38 were assessed using co-immunoprecipitation (Co-IP) experiments. Western blotting analysis was used to evaluate the levels of protein expression and phosphorylation. Results: Human sperm hyperactivation and acrosome reaction were inhibited by 17-AAG, suggesting that Hsp90 is involved in human sperm capacitation. In addition, Co-IP experiments revealed that 17-AAG reduced the interaction between Hsp90 and Cdc37, leading to the dissociation of Erk1/2 from the Hsp90-Cdc37 protein complex. Western blotting analysis revealed that levels of Erk1/2 and its phosphorylated form were subsequently decreased. Decreasing of Hsp90-Cdc37 complex also affected the interaction between Hsp90 and p38. Nevertheless, p38 dissociated from the Hsp90 protein complex and was activated by autophosphorylation. Conclusions: Taken together, our findings indicate that Hsp90 is involved in human sperm hyperactivation and acrosome reaction. In particular, Hsp90 and its co-chaperone Cdc37 form a protein complex with Erk1/2 and p38 to regulate their kinase activity. These results suggest that Hsp90 regulates human sperm capacitation via the Erk1/2 and p38 MAPK signaling pathways.
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