Forskolin stimulates porcine sperm capacitation by increasing calcium uptake

Okamura, Nobuyuki; Tanba, Michiko; Fukuda, Atsunori; Sugita, Yoshiki; Nagai, Taku

doi:10.1016/0014-5793(93)81309-n

Cited by 19 publications

(7 citation statements)

References 17 publications

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“…4). This forskolin-mediated increase in human sperm capacitation is consistent with that reported in boar spermatozoa [32]. Since forskolin stimulates sperm membrane-bound adenylyl cyclase activity [33], it appears that the forskolin effects reported here in human spermatozoa might be mediated through adenylyl cyclase activation.…”

Section: Discussionsupporting

confidence: 87%

Cyclic Adenosine 3′,5′monophosphate-Dependent Regulation of Protein Tyrosine Phosphorylation in Relation to Human Sperm Capacitation and Motility1

Leclerc

Lamirande

Gagnon

1996

Biology of Reproduction

372

274

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The involvement of cAMP in the process of sperm capacitation has been the subject of several studies. In addition, the importance of protein-tyrosine phosphorylation in this process has been investigated, although only a few studies have been reported in the human. Since agents regulating the intracellular concentrations of cAMP affect sperm capacitation rates, the role of cAMP on the expression of phosphotyrosine-containing proteins was investigated during human sperm capacitation. Fetal cord serum ultrafiltrate, a known capacitation inducer in human spermatozoa, caused an increase in the phosphotyrosine content of 105- and 81-kDa proteins (p105 and p81), the two major phosphotyrosine-containing proteins of human spermatozoa. Similar effects were observed when spermatozoa were incubated with phosphodiesterase inhibitors or cell-permeant cAMP analogs, suggesting that cAMP is involved in these two processes. Forskolin, an adenylyl cyclase activator, also caused an increase in both sperm capacitation rates and tyrosine phosphorylation of p105 and p81, while 12-O-tetradecanoyl phorbol 13-acetate stimulated both capacitation and tyrosine phosphorylation of p105 and p81 only when spermatozoa were incubated in the presence of bicarbonate, in agreement with its reported effects on cAMP production and hamster sperm capacitation. The inhibition of these phenomena by cAMP-dependent protein kinase inhibitors, and the stimulation by protein phosphatase inhibitors, suggest that Ser/Thr protein phosphorylation plays an important role in the regulation of both sperm capacitation and protein-tyrosine phosphorylation pathways. However, observations that both calyculin A and okadaic acid stimulated sperm capacitation, whereas only calyculin A increased p105 and p81 phosphotyrosine content and sperm velocity, suggest that protein phosphatase PP1 is involved in the two latter phenomena while PP2A mediates sperm capacitation. These results suggest that divergent pathways might regulate tyrosine phosphorylation of p105 and p81 and sperm capacitation after cAMP-dependent phosphorylation of an intermediate protein.

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Section: Discussionsupporting

confidence: 87%

Cyclic Adenosine 3′,5′monophosphate-Dependent Regulation of Protein Tyrosine Phosphorylation in Relation to Human Sperm Capacitation and Motility1

Leclerc

Lamirande

Gagnon

1996

Biology of Reproduction

372

274

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“…The sperm membrane undergoes numerous modifications related to capacitation [4], including structural changes to protein-lipid organization [5,6] and plasma membrane fluidization [7][8][9]. Other molecular events that coincide with capacitation are the activation of ion channels [10] and calcium uptake [11][12][13][14], the generation of cAMP [15,16], and the production of reactive oxygen species [17,18].…”

Section: Sperm Capacitationmentioning

confidence: 99%

Capacitation Is Associated with Tyrosine Phosphorylation and Tyrosine Kinase-Like Activity of Pig Sperm Proteins1

Tardif

Dubé

Chevalier

et al. 2001

Biology of Reproduction

187

135

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Capacitation represents the final maturational steps that render mammalian sperm competent to fertilize, either in vivo or in vitro. Capacitation is defined as a series of events that enables sperm to bind the oocyte and undergo the acrosome reaction in response to the zona pellucida. Although the molecular mechanisms involved are not fully understood, sperm protein phosphorylation is associated with capacitation. The hypothesis of this study is that protein tyrosine phosphorylation and kinase activity mediate capacitation of porcine sperm. Fresh sperm were incubated in noncapacitating or capacitating media for various times. Proteins were extracted with SDS, subjected to SDS-PAGE, and immunoblotted with an antiphosphotyrosine antibody. An M(r) 32 000 tyrosine-phosphorylated protein (designated as p32) appeared only when the sperm were incubated in capacitating medium and concomitant with capacitation as assessed by the ionophore-induced acrosome reaction. The p32 was soluble in Triton X-100. Fractionation of sperm proteins with Triton X-114 demonstrated that after capacitation, this tyrosine phosphoprotein is located in both the cytosol and the membrane. Enzyme renaturation of sperm proteins was conducted in gels with or without either poly glu:tyr (a tyrosine kinase substrate) or kemptide (a protein kinase A substrate). An M(r) 32 000 enzyme with kinase behavior was observed in all gels but was preferentially phosphorylated on tyrosine, as assessed by phosphorimagery and by thin layer chromotography to identify the phosphoamino acids. Indirect immunolocalization showed that the phosphotyrosine residues redistribute to the acrosome during capacitation, which is an appropriate location for a protein involved in the acquisition of fertility.

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“…Although there is a report that interaction between laminin, entrapped in the expanded cumuli, and specific integrins present on the sperm membrane can initiate AR [86], most evidence suggests that progesterone and zona pellucida initiate sperm acrosome reaction in vitro [87][88][89][90]. As to the mechanisms, it is suggested that increasing Ca 2+ caused by entry of Ca 2+ through sperm plasma membrane Ca 2+ channels triggers the acrosome reaction during fertilization [91,92]. In addition to Ca 2+ , sperm also requires bicarbonate for acrosome reaction [93].…”

Section: Sperm Acrosome Reactionmentioning

confidence: 99%

Molecular Mechanisms Underlying Pig Oocyte Maturation and Fertilization

Sun

Nagai

2003

Journal of Reproduction and Development

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Abstract. Since the pig is not only an important farm animal, but also a model animal for biomedical applications, the development of reproductive technologies in this species has been very important. In vitro oocyte maturation and fertilization (IVM-IVF) are basic techniques for a number of oocyte-or embryo-related technologies. The practical aspects for pig oocyte IVM-IVF have been reviewed, while the molecular mechanisms underlying oocyte meiotic maturation and fertilization have not been well summarized, although accumulating data have been obtained in recent one decade. This review will focus on what is known about the molecular mechanisms of porcine oocyte maturation and fertilization such as first meiosis resumption, meiotic spindle assembly, second meiosis metaphase (MII) arrest during oocyte maturation, sperm-egg recognition and fusion, sperm acrosome reaction, second meiosis resumption, sperm chromatin decondensation, and pronucleus formation during fertilization, as well as the establishment of polyspermy block. Key words: Pig, Oocyte, Meiosis, Fertilization, Polyspermy (J. Reprod. Dev. 49: [347][348][349][350][351][352][353][354][355][356][357][358][359] 2003) nimal reproductive technology has been very important in the last two decades, and the development of efficient procedures for assisted reproduction in livestock has generated multiple opportunities for commercialization [1]. The d e v e l o p m e n t o f e f f i c i e n t r e p r o d u c t i v e biotechnology has been increasingly required in pigs, since it is not only an important farm animal, b u t a l s o a m o d e l a n i m a l f o r b i o m e d i c a l applications, such as human disease processes, d r u g d e v e l o p m e n t, a n d h u m a n o r g a n xenotransplantation [2]. Recently, somatic cell cloned pigs have been produced [3][4][5], and the productio n of gene kno ck out pig ha s been achieved by nuclear transfer of donor cells with the modification of the α (1,3)-galactosyltrnasferase (GalT) gene [6]. However, the efficiency is still extremely low. Although several systems have been established to generate embryos in vitro, the quality of embryos produced in vitro is inferior to those produced in vivo. The major problems include improper oocyte maturation, both nucleus and cytoplasmic, and polyspermy. Despite the progress, the quality of oocytes matured in vitro, defined as the potential of that oocyte to develop into a viable offspring, is still not satisfactory, limiting the improvement of other reproductive techniques in pigs [7]. Thus, the importance of the development and identification of defined in vitro conditions for oocyte maturation and fertilization s ho u ld no t be un der es t im a t ed , s inc e m os t reproductive technologies rely on these basic techniques. The technology of pig oocyte in vitro maturation, fertilization and embryo development and related problems have been well reviewed [8-

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Forskolin stimulates porcine sperm capacitation by increasing calcium uptake

Cited by 19 publications

References 17 publications

Cyclic Adenosine 3′,5′monophosphate-Dependent Regulation of Protein Tyrosine Phosphorylation in Relation to Human Sperm Capacitation and Motility1

Cyclic Adenosine 3′,5′monophosphate-Dependent Regulation of Protein Tyrosine Phosphorylation in Relation to Human Sperm Capacitation and Motility1

Capacitation Is Associated with Tyrosine Phosphorylation and Tyrosine Kinase-Like Activity of Pig Sperm Proteins1

Molecular Mechanisms Underlying Pig Oocyte Maturation and Fertilization

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