Reduction of nitric oxide level leads to spontaneous resumption of meiosis in diplotene-arrested rat oocytes culturedin vitro

Abstract

The present study was aimed to investigate whether a decrease of nitric oxide (NO) level is beneficial for sponateous resumptiom of meiosis in diplotene-arrested oocytes cultured in vitro. For this purpose, diplotene-arrested oocytes were collected from ovary of immature female rats after a single subcutaneous injection of 20 IU pregnant mare's serum gonadotropins (PMSG) for 48 h. In vitro effects of S-nitroso-l-acetyl penicillamine (SNAP; an NO donor) and aminoguanidine (AG; an inducible NOS [iNOS] inhibitor), intracellular NO, cyclic guanosine monophosphate (cGMP), Cdc25B, Thr-14/Tyr-15 and Thr-161 phosphorylated cyclindependent kinase-1 (CDK1), and cyclin B1 levels were analyzed. The SNAP inhibited spontaneous meiotic resumption form diplotene arrest in a concentration-dependent manner, while AG-induced meiotic resumption form diplotene in 0.1 mmol/L 3-isobutyl-1-methylxanthine (IBMX)-treated oocytes in a concentration-dependent manner. The intracellular NO as well as cGMP levels were decreased significantly during spontaneous meiotic resumption from diplotene arrest. The reduction of Cdc25B expression level was associated with the accumulation of Thr-14/Tyr-15 phosphorylated CDK1 level. However, Thr-161 phosphorylated CDK1 as well as cyclin B1 levels were reduced significantly during meiotic resumption from diplotene arrest. Taken together, these data suggest that the inhibition of iNOS expression leads to a decrease of NO and cGMP levels thereby decreasing Cdc25B level. The reduced CDC25 B level leads to accumulation of Thr-14/Tyr-15 phosphorylated CDK1 level. As a result, Thr-161 phosphorylated CDK1 as well as cyclin B1 levels are decreased leading to maturation-promoting factor (MPF) inactivation. The inactive MPF finally induced meiotic resumption from diplotene stage in rat oocytes cultured in vitro.

Maturation promoting factor destabilization mediates human chorionic gonadotropin induced meiotic resumption in rat oocytes

“…These results suggest the hCG surge modulated specific phosphorylation status of Cdk1 and increased Cdk1 activity during meiotic exit from diplotene as well as M‐II arrest. Similarly, changes in specific phosphorylation status of Cdk1 and involvement of Cdk1 activity have been reported during meiotic resumption from diplotene arrest in rat (Pandey & Chaube ; Tiwari & Chaube ), mouse (Solc et al . ; Adhikari et al .…”

Calcium Signaling During Meiotic Cell Cycle Regulation and Apoptosis in Mammalian Oocytes

“…Pituitary gonadotropins surge disrupt gap junctions and thereby cumulus‐oocyte communications resulting interruption in supply of several signal molecules and inhibitory factors to the oocyte leading to meiotic resumption from diplotene arrest (Zhang and Fissore, ; Tiwari and Chaube, ). The physical removal of encircling granulosa cells also disrupt the supply of various signal molecules and inhibitory factors from granulosa cells to the oocyte causing spontaneous meiotic resumption from diplotene arrest under in vitro culture conditions (Pandey et al, ; Hwang and Cheon, ; Pandey and Chaube, , ; Prasad et al, ; Tiwari et al, ).…”

“…The CaMKII activates Wee 1 that destabilizes MPF by inducing phosphorylation of Thr14/Tyr15 of Cdk1 (a catalytic unit of MPF) and triggers degradation of cyclin B1 (a regulatory subunit of MPF) (Fan et al, ; Yoo and Smith, ). The destabilized MPF and/or Cdk1 activity triggers meiotic resumption from diplotene arrest in rat oocytes (Pandey and Chaube, , ; Prasad et al, ; Tiwari and Chaube, ) (Fig. ).…”

Nitric Oxide Modulates Postnatal Bone Marrow-Derived Mesenchymal Stem Cell Migration

“…In the presence of NO, cell division is inhibited in both the SN-1 and SN-2 groups. This would suggest that NO may have direct effect on the ability of the cell to form a functional mitotic or meiotic spindles (Gelaude et al, 2015), may suppress actin mediated cytokinesis or enter cell division cycle (Phung et al, 2006; Pandey et al, 2010; Pandey and Chaube, 2015). These observations suggest that NO may more specifically affect cytoskeletal proteins that are associated with cell division.…”