Actin-related protein 2/3 complex-based actin polymerization is critical for male fertility

Abstract

SUMMARYThe actin-related protein 2/3 (Arp2/3) complex is critical for regulation of actin polymerization, which is associated with sperm motility and capacitation status. However, the function of the Arp2/3 complex in male fertility has not yet been fully elucidated. Therefore, this study was designed to investigate the role of the Arp2/3 complex in different processes in spermatozoa and its consequences on fertilization and early embryonic development. In this in vitro study, mouse spermatozoa were incubated with different concentrations (10, 100, and 500 lM) of CK-636, an Arp2/3 complex antagonist. Our results demonstrated that inhibition of the Arp2/ 3 complex by high concentrations (100 and 500 lM) of CK-636 induced hyper-activated motility and acrosomal reaction, whereas intracellular calcium and tyrosine phosphorylation levels in spermatozoa were inhibited. Moreover, exposure of spermatozoa to the highest concentration of CK-636 reduced fertilization and embryo development. Interestingly, fertilization was significantly increased after treatment with 100 lM CK-636, whereas embryonic development was significantly decreased. Therefore, we conclude that the Arp2/3 complex plays a decisive role in regulation of sperm function and male fertility via actin polymerization. We anticipate that the Arp2/3 complex may have clinical application as marker for male fertility and male contraceptive targeting.

Proteomic identification of cryostress in epididymal spermatozoa

“…Sperm capacitation and the acrosome reaction are closely associated with actin polymerization [63]. F-actin in the actin-related pathways plays a major role in the remodeling of actin structure, the acrosome reaction, and male fertility [64]. It is possible that the significant alterations of capacitation status in our results are related to these pathways (Fig.…”

Role of Wasp and the small GTPases RhoA, RhoB, and Cdc42 during capacitation and acrosome reaction in spermatozoa of English guinea pigs

“…Capacitation and the acrosome reaction both involve polymerization of actin, which is located in the post‐acrosomal and equatorial regions of spermatozoa (Olson and Winfrey, ; Castellani‐Ceresa et al, ; Sánchez‐Gutiérrez et al, ; Itach et al, ; Breitbart and Finkelstein, ; Lee et al, ). Indeed, F‐actin is present in the spermatozoa of different mammalian species (Flaherty et al, ).…”

Role of Actin Cytoskeleton During Mammalian Sperm Acrosomal Exocytosis

“…Evidence from different laboratories indicates that actin polymerization occurs during capacitation in several mammalian species such as boar, guinea pig, mouse, rabbit, bovine, and human sperm (Castellani-Ceresa et al 1993;Brener et al 2003;Cabello-Ag€ ueros et al 2003;Baltiérrez-Hoyos et al 2012;Romarowski et al 2015;Lee et al 2015). The increase in F-actin was observed in the sperm head as well as in the flagellum.…”

“…On the other hand, activation of PKC by phorbol myristate acetate enhanced PIP2 and F-actin formation mediated by PI4K activity, while the PI3K activity and intracellular PIP3 levels were reduced. Lee et al (2015), ChiqueteFelix et al (2009) In addition, it was recently reported that diacylglycerol stimulates acrosomal exocytosis by feeding into a PKC-and PLD1-dependent positive loop that continuously supplies phosphatidylinositol 4,5-bisphosphate (Lopez et al 2012). Roldan and Dawes (1993) suggested that PLD does not make a substantial contribution to the events leading to acrosomal exocytosis.…”

“…Recently, Lee and coworkers (Lee et al 2015) reported that inhibition of the Arp2/3 complex using high concentrations of CK-636 induced hyperactivated motility and acrosomal exocytosis. Moreover, inhibition of the Arp2/3 complex with CK-636 decreased the ratio of F-actin/G-actin in a dose-dependent manner.…”