The Journey of the Porcine Spermatozoa from Its Origin to the Fertilization Site: The Road In Vivo vs. In Vitro
Juan Carlos Gardón, Katy Satué in Biotechnologies Applied to Animal Reproduction, 2020
It is difficult to specify the exact timing of the events that take place during the sperm capacitation process. Under in vivo conditions, sperm capacitation could last 2 or 3 hours, depending on the place of semen deposition (Hunter and Dziuk, 1968; Harrison, 1996). What seems clear is that OF modulates the rate of sperm capacitation events in vivo, and probably also when it is added to an in vitro system. Once spermatozoa are sequentially exposed to UF and OF, these fluids should be able to regulate the rate of the process (Rodriguez-Martinez, 2007). However, it has been described that in vitro capacitation is initiated within a few seconds or minutes after spermatozoa come into contact with a HCO-3-enriched capacitating medium because HCO-3 rapidly stimulates sAC (maximum within 60 s) that triggers PKA-dependent protein phosphorylation cascade (Harrison, 2004; Visconti, 2009). One of the first signals of that is the activation of spermatozoa motility, but also a scrambling of plasma membrane phospholipids that produces an increase in plasma membrane fluidity (Harrison and Miller, 2000). Significantly later, the membrane fluidity increases again but by the action of the presence of albumin in the incubation medium, which removes or redistributes the cholesterol in the spermatozoa plasma membrane (Flesch et al., 2001). Another late effect (>60 min) of HCO-3 in in vitro sperm capacitation is the activation of tyrosine kinases and the subsequent Tyr-P (Visconti, 2009).
Evaluation of sperm
David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham in Textbook of Assisted Reproductive Techniques, 2017
The acrosome is an intracellular organelle, similar to a lysosome, which forms a cap-like structure over the apical portion of the sperm nucleus (36). The acrosome contains multiple hydrolytic enzymes, including hyaluronidase, neuraminidase, proacrosin, phospholipase, and acid phosphatase, which, when released, are thought to facilitate sperm passage through the cumulus mass, and possibly the zona pellucida as well (Figure 4.4). In fact, only acrosome-reacted sperm is capable of penetrating the zona pellucida, binding to the oolemma, and fusing with the oocyte (37). Once sperm undergoes capacitation, it is capable of an acrosome reaction. This reaction is apparently triggered by fusion of the sperm plasma membrane with the outer acrosomal membrane at multiple sites, leading to diffusion of the acrosomal enzymes into the extracellular space. This leads to the dissolution of the plasma membrane and acrosome, leaving the inner acrosomal membrane exposed over the head of the sperm (Figure 4.5). Although electron microscopy has produced many elegant pictures of acrosome-intact and acrosome-reacted sperm, it is not always possible to know whether sperm that fail to exhibit an acrosome have truly acrosome reacted, or could possibly be dead. In addition, electron microscopy is not a technique that is available to all andrologists.
JAK-STAT pathway: Testicular development, spermatogenesis and fertility
Rajender Singh in Molecular Signaling in Spermatogenesis and Male Infertility, 2019
The process of capacitation takes place in the female reproductive tract, which must be triggered by molecules present in the female reproductive tract (84). IL-6, an endometrial secretion, is a well-investigated cytokine, inducing capacitation (41). IL-6 concentration is found to be higher in preovulatory periods than in the luteal phase (85), and both JAK1 and Tyk2 are known to be activated in the presence of IL-6 (86). Localization studies showing the IL-6 receptor in the tail region (41), which also has JAK2 (80), suggests JAK2 tyrosine phosphorylation. This was also supported by in vitro capacitation experiments showing maximum tyrosine phosphorylation in the tail region (80).
Sperm performance in oligoasthenoteratozoospermic patients is induced by a nutraceuticals mix, containing mainly myo-inositol
Published in Systems Biology in Reproductive Medicine, 2021
Marta Santoro, Saveria Aquila, Giampiero Russo
Our recent data suggested that sperm has the ability to modulate autonomously the energetic substrate availability on the basis of its energy needs independently from the systemic regulation (De Amicis et al. 2011; Guido et al. 2011). Our previous studies demonstrated metabolic reprogramming during the switch from uncapacitated to capacitated sperm. An Energy expenditure occurs during capacitation. Specifically, sperm glucose metabolism through the PPP is very important (Aquila et al. 2005a, 2005b). Therefore, we evaluated the action of these treatments on the activity of the G6PDH, the first enzyme of the PPP. Treatment with these substances either in vitro and in vivo was able to significantly induce the G6PDH activity on B and C samples with respect to the untreated A (Figure 5). It seems that this enzymatic activity increased to a greater extent than normal subjects in vivo and in vitro treated sperm. We also evaluated the effect of MI on G6PDH activity in normospermic men (group named, HM). Interestingly, in healthy sperm samples, the G6PDH activity is significantly increased when MI was added in vitro. These results suggest that MI also improves sperm performance in normozoospermic patients. In OAT patients samples, the enzyme activity is positively affected by MI, although to lower extent when compared to normal patient samples.
Participation of signaling proteins in sperm hyperactivation
Published in Systems Biology in Reproductive Medicine, 2022
Joaquín Cordero-Martínez, Guadalupe Elizabeth Jimenez-Gutierrez, Charmina Aguirre-Alvarado, Verónica Alacántara-Farfán, Germán Chamorro-Cevallos, Ana L. Roa-Espitia, Enrique O. Hernández-González, Lorena Rodríguez-Páez
Capacitation is influenced by the activities of a wide variety of proteins. Soluble adenylyl cyclase (sAC) strongly influences the signaling cascade that controls sperm motility (Esposito et al. 2004; Buffone et al. 2014). sAC activity is modulated by the presence of HCO3− (Xie et al. 2006; Wang D et al. 2007), and its activation leads to the production of adenosine 3′,5′-cyclic monophosphate (cAMP), which in turn modulates the sperm-specific Na+/H+ exchanger (sNHE) (Wang D et al. 2007; Touré 2019). sNHE is an integral membrane protein that regulates the Na+/H+ exchange and pHi of rodent sperms during capacitation (Chen SR, Batool, et al. 2016; Zhang et al. 2017). The t-complex protein 11 (TCP11) is yet another protein that exerts strong influence over the signaling pathway such as cAMP/PKA and tyrosine phosphorylation and sperm motility (Castaneda et al. 2020).
Effects of zinc deficiency on impaired spermatogenesis and male infertility: the role of oxidative stress, inflammation and apoptosis
Published in Human Fertility, 2020
Asghar Beigi Harchegani, Heydar Dahan, Eisa Tahmasbpour, Hamid Bakhtiari kaboutaraki, Alireza Shahriary
Zinc plays a multifaceted role in sperm function and fertility of men through various mechanisms (Figure 1). It is now considered as one of the main nutrients in the male reproductive system for proper sperm formation and motility (Khan et al., 2011). Zinc is not only a cofactor for various proteins involved in antioxidant defence, and electron transport, but also it is essential for the production, storage, secretion and function of numerous enzymes such as RNA polymerases, alcohol dehydrogenase, carbonic anhydrase (CA), alkaline phosphatase that are important in normal function of spermatozoa and prevention of sperm damage (Omu et al., 2015). Numerous studies have shown positive effects of zinc on semen quality and male factor infertility (Guzikowski et al., 2015). Zinc is necessary for testicular development and normal spermatogenesis (Colagar et al., 2009). It is also a main factor for DNA replication and packaging, DNA transcription, protein synthesis, cell proliferation, differentiation and apoptosis, which are major parts of sperm development (Chia et al., 2000; Croxford, McCormick, & Kelleher, 2011). Zinc has a regulatory function in steroid hormone synthesis as a critical step for normal spermatogenesis. It plays a regulatory role in the process of sperm capacitation and acrosome reaction (Kothari & Chaudhari, 2016). Zinc protects Leydig cells from damage due to its anti-oxidative properties (Colagar et al., 2009). As the body has no specialized zinc storage system, a daily intake of zinc is, therefore, critical for normal function of the male reproductive system.
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