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A moderate increase of hydrogen peroxide level is beneficial for spontaneous resumption of meiosis from diplotene arrest in rat oocytes cultured in vitro.

Pandey AN, Chaube SK - Biores Open Access (2014)

Bottom Line: The increased intra-oocyte H2O2 level induced Thr-14/Tyr-15 phosphorylation of CDK1, while Thr-161 phosphorylated CDK1 and cyclin B1 levels were reduced significantly.These results suggest that a decreased level of intra-oocyte cAMP is associated with an increased level of H2O2.The increased level of H2O2 was associated with high phosphorylation of Thr-14/Tyr-15 and dephosphorylation of the Thr-161 residue of CDK1 and reduced the cyclin B1 level, which eventually inactivated MPF.

View Article: PubMed Central - PubMed

Affiliation: Cell Physiology Laboratory, Department of Zoology, Banaras Hindu University , Varanasi, India .

ABSTRACT
Hydrogen peroxide (H2O2) acts as a signaling molecule and modulates various aspects of cell functions in a wide variety of cells including mammalian germ cells. We examined whether a decreased level of intra-oocyte cyclic 3',5'-adenosine monophosphate (cAMP) leads to accumulation of H2O2, and if so, whether a moderate increase of H2O2 inactivates maturation promoting factor (MPF) during spontaneous resumption of meiosis in rat oocytes cultured in vitro. Removal of cumulus cells and culture of denuded oocytes in vitro significantly decreased oocyte cAMP level and led to spontaneous meiotic resumption from diplotene arrest. The reduced oocyte cAMP level was associated with an increased oocyte H2O2 level and reduced catalase activity. Exogenous supplementation of H2O2 induced meiotic resumption from diplotene arrest in a concentration- and time-dependent manner in oocytes treated with 0.1 mM of 3-isobutyl-1-methylxanthine, while dibutyryl-cAMP and 3-t-butyl-4-hydroxyanisole inhibited the stimulatory effect of exogenous H2O2. The increased intra-oocyte H2O2 level induced Thr-14/Tyr-15 phosphorylation of CDK1, while Thr-161 phosphorylated CDK1 and cyclin B1 levels were reduced significantly. These results suggest that a decreased level of intra-oocyte cAMP is associated with an increased level of H2O2. The increased level of H2O2 was associated with high phosphorylation of Thr-14/Tyr-15 and dephosphorylation of the Thr-161 residue of CDK1 and reduced the cyclin B1 level, which eventually inactivated MPF. The MPF inactivation triggered spontaneous resumption of meiosis from diplotene arrest in rat oocytes cultured in vitro.

No MeSH data available.


Related in: MedlinePlus

Schematic hypothetical diagram showing possible involvement of cAMP and H2O2 during spontaneous meiotic resumption from diplotene arrest of rat oocyte. The decrease of intra-oocyte cAMP level results in the generation of H2O2. A rise of H2O2 induces Thr-14/Tyr-15 phosphorylated CDK1, and also reduces Thr-161 phosphorylated CDK1. Changes in the level of specific phosphorylation of CDK1 results in dissociation and degradation of cyclin B1, which finally triggers maturation promoting factor (MPF) destabilization. The destabilized MPFs lead to spontaneous meiotic resumption from diplotene arrest in rat eggs cultured in vitro.
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f10: Schematic hypothetical diagram showing possible involvement of cAMP and H2O2 during spontaneous meiotic resumption from diplotene arrest of rat oocyte. The decrease of intra-oocyte cAMP level results in the generation of H2O2. A rise of H2O2 induces Thr-14/Tyr-15 phosphorylated CDK1, and also reduces Thr-161 phosphorylated CDK1. Changes in the level of specific phosphorylation of CDK1 results in dissociation and degradation of cyclin B1, which finally triggers maturation promoting factor (MPF) destabilization. The destabilized MPFs lead to spontaneous meiotic resumption from diplotene arrest in rat eggs cultured in vitro.

Mentions: In summary, data from the present study suggest that the decrease of intra-oocyte cAMP induces the generation of H2O2, possibly by reducing catalase activity in oocytes. A moderate increase of H2O2 level induces phosphorylation of Thr-14/Tyr-15 but reduces Thr-161 phosphorylation of CDK1. Changes in the specific phosphorylation status of CDK1 triggered dissociation and degradation of cyclin B1 leading to MPF inactivation. The inactive MPF finally induces spontaneous meiotic resumption from diplotene arrest in rat oocytes cultured in vitro (Fig. 10). These data suggest that the increase of a moderate level of ROS under in vitro culture conditions could be one of the causative factors that trigger spontaneous resumption of meiosis during in vitro maturation or in vitro fertilization in several mammalian species including human.


A moderate increase of hydrogen peroxide level is beneficial for spontaneous resumption of meiosis from diplotene arrest in rat oocytes cultured in vitro.

Pandey AN, Chaube SK - Biores Open Access (2014)

Schematic hypothetical diagram showing possible involvement of cAMP and H2O2 during spontaneous meiotic resumption from diplotene arrest of rat oocyte. The decrease of intra-oocyte cAMP level results in the generation of H2O2. A rise of H2O2 induces Thr-14/Tyr-15 phosphorylated CDK1, and also reduces Thr-161 phosphorylated CDK1. Changes in the level of specific phosphorylation of CDK1 results in dissociation and degradation of cyclin B1, which finally triggers maturation promoting factor (MPF) destabilization. The destabilized MPFs lead to spontaneous meiotic resumption from diplotene arrest in rat eggs cultured in vitro.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4120648&req=5

f10: Schematic hypothetical diagram showing possible involvement of cAMP and H2O2 during spontaneous meiotic resumption from diplotene arrest of rat oocyte. The decrease of intra-oocyte cAMP level results in the generation of H2O2. A rise of H2O2 induces Thr-14/Tyr-15 phosphorylated CDK1, and also reduces Thr-161 phosphorylated CDK1. Changes in the level of specific phosphorylation of CDK1 results in dissociation and degradation of cyclin B1, which finally triggers maturation promoting factor (MPF) destabilization. The destabilized MPFs lead to spontaneous meiotic resumption from diplotene arrest in rat eggs cultured in vitro.
Mentions: In summary, data from the present study suggest that the decrease of intra-oocyte cAMP induces the generation of H2O2, possibly by reducing catalase activity in oocytes. A moderate increase of H2O2 level induces phosphorylation of Thr-14/Tyr-15 but reduces Thr-161 phosphorylation of CDK1. Changes in the specific phosphorylation status of CDK1 triggered dissociation and degradation of cyclin B1 leading to MPF inactivation. The inactive MPF finally induces spontaneous meiotic resumption from diplotene arrest in rat oocytes cultured in vitro (Fig. 10). These data suggest that the increase of a moderate level of ROS under in vitro culture conditions could be one of the causative factors that trigger spontaneous resumption of meiosis during in vitro maturation or in vitro fertilization in several mammalian species including human.

Bottom Line: The increased intra-oocyte H2O2 level induced Thr-14/Tyr-15 phosphorylation of CDK1, while Thr-161 phosphorylated CDK1 and cyclin B1 levels were reduced significantly.These results suggest that a decreased level of intra-oocyte cAMP is associated with an increased level of H2O2.The increased level of H2O2 was associated with high phosphorylation of Thr-14/Tyr-15 and dephosphorylation of the Thr-161 residue of CDK1 and reduced the cyclin B1 level, which eventually inactivated MPF.

View Article: PubMed Central - PubMed

Affiliation: Cell Physiology Laboratory, Department of Zoology, Banaras Hindu University , Varanasi, India .

ABSTRACT
Hydrogen peroxide (H2O2) acts as a signaling molecule and modulates various aspects of cell functions in a wide variety of cells including mammalian germ cells. We examined whether a decreased level of intra-oocyte cyclic 3',5'-adenosine monophosphate (cAMP) leads to accumulation of H2O2, and if so, whether a moderate increase of H2O2 inactivates maturation promoting factor (MPF) during spontaneous resumption of meiosis in rat oocytes cultured in vitro. Removal of cumulus cells and culture of denuded oocytes in vitro significantly decreased oocyte cAMP level and led to spontaneous meiotic resumption from diplotene arrest. The reduced oocyte cAMP level was associated with an increased oocyte H2O2 level and reduced catalase activity. Exogenous supplementation of H2O2 induced meiotic resumption from diplotene arrest in a concentration- and time-dependent manner in oocytes treated with 0.1 mM of 3-isobutyl-1-methylxanthine, while dibutyryl-cAMP and 3-t-butyl-4-hydroxyanisole inhibited the stimulatory effect of exogenous H2O2. The increased intra-oocyte H2O2 level induced Thr-14/Tyr-15 phosphorylation of CDK1, while Thr-161 phosphorylated CDK1 and cyclin B1 levels were reduced significantly. These results suggest that a decreased level of intra-oocyte cAMP is associated with an increased level of H2O2. The increased level of H2O2 was associated with high phosphorylation of Thr-14/Tyr-15 and dephosphorylation of the Thr-161 residue of CDK1 and reduced the cyclin B1 level, which eventually inactivated MPF. The MPF inactivation triggered spontaneous resumption of meiosis from diplotene arrest in rat oocytes cultured in vitro.

No MeSH data available.


Related in: MedlinePlus