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Reprod Med Biol
2008 Dec 13;81:3-9. doi: 10.1007/s12522-008-0001-x.
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Inhibition of apoptosis by ascorbic and dehydroascorbic acids in Xenopus egg extracts.
Saitoh T
,
Tsuchiya Y
,
Kinoshita T
,
Itoh M
,
Yamashita S
.
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Purpose: The viability of mammalian eggs after ovulation is reported to be improved by the presence of ascorbic acid in the culture medium. However, the pro-survival mechanisms of ascorbic acid are poorly understood. The molecular pathways of apoptosis are evolutionarily conserved among animal species, and Xenopus eggs are technically and ethically more suitable for biochemical analyses than mammalian eggs. We used Xenopus egg cytoplasmic extracts to examine the direct intracellular effects of ascorbic acid.
Methods: Incubation of egg extracts for more than 4 h induces the spontaneous release of cytochrome c from mitochondria. This event triggers the activation of caspases, cleavage of substrate proteins, and execution of apoptosis. Multiple signal transduction pathways including proteolysis and protein phosphorylation are also involved in this process. We examined whether any of these events might be inhibited by the addition of ascorbic acid.
Results: Ascorbic acid showed no effect against cytochrome c release, but prevented caspase activation and substrate cleavage. Ascorbic acid also blocked the proteolysis of apoptosis inhibitor proteins and the dephosphorylation of p42 MAP kinase. However, dehydroascorbic acid (oxidized form of ascorbic acid) and acetate (unrelated acid) were equally effective, indicating that these effects were primarily due to their acidity. In addition, dehydroascorbic acid inhibited caspase activities directly in vitro.
Conclusions: The anti-apoptotic effect of ascorbic acid in Xenopus egg extracts is mainly due to cytoplasmic acidification rather than its intracellular antioxidant activity. Instead, oxidative conversion of ascorbic acid into dehydroascorbic acid may inhibit apoptosis through the inhibition of caspases.
Bode,
Spontaneous decay of oxidized ascorbic acid (dehydro-L-ascorbic acid) evaluated by high-pressure liquid chromatography.
1990, Pubmed
Bode,
Spontaneous decay of oxidized ascorbic acid (dehydro-L-ascorbic acid) evaluated by high-pressure liquid chromatography.
1990,
Pubmed
Cárcamo,
Vitamin C is a kinase inhibitor: dehydroascorbic acid inhibits IkappaBalpha kinase beta.
2004,
Pubmed
Coll,
Neutral sphingomyelinase-induced ceramide triggers germinal vesicle breakdown and oxidant-dependent apoptosis in Xenopus laevis oocytes.
2007,
Pubmed
,
Xenbase
Comizzoli,
Overcoming poor in vitro nuclear maturation and developmental competence of domestic cat oocytes during the non-breeding season.
2003,
Pubmed
Dalvit,
Effect of alpha-tocopherol and ascorbic acid on bovine oocyte in vitro maturation.
2005,
Pubmed
Daruwala,
Cloning and functional characterization of the human sodium-dependent vitamin C transporters hSVCT1 and hSVCT2.
1999,
Pubmed
,
Xenbase
Deming,
Study of apoptosis in vitro using the Xenopus egg extract reconstitution system.
2006,
Pubmed
,
Xenbase
De Tullio,
Hopes, disillusions and more hopes from vitamin C.
2004,
Pubmed
Eppig,
Conditions that affect acquisition of developmental competence by mouse oocytes in vitro: FSH, insulin, glucose and ascorbic acid.
2000,
Pubmed
Flament,
Xenopus oocyte maturation: cytoplasm alkalization is involved in germinal vesicle migration.
1996,
Pubmed
,
Xenbase
Greenwood,
XLX is an IAP family member regulated by phosphorylation during meiosis.
2007,
Pubmed
,
Xenbase
Guérin,
Oxidative stress and protection against reactive oxygen species in the pre-implantation embryo and its surroundings.
2001,
Pubmed
Holley,
Reaper eliminates IAP proteins through stimulated IAP degradation and generalized translational inhibition.
2002,
Pubmed
,
Xenbase
Nakajima,
Structure, expression, and function of the Xenopus laevis caspase family.
2000,
Pubmed
,
Xenbase
Newmeyer,
Cell-free apoptosis in Xenopus egg extracts: inhibition by Bcl-2 and requirement for an organelle fraction enriched in mitochondria.
1994,
Pubmed
,
Xenbase
Nutt,
Metabolic regulation of oocyte cell death through the CaMKII-mediated phosphorylation of caspase-2.
2005,
Pubmed
,
Xenbase
Sellier,
Intracellular acidification delays hormonal G2/M transition and inhibits G2/M transition triggered by thiophosphorylated MAPK in Xenopus oocytes.
2006,
Pubmed
,
Xenbase
Tao,
Exposure to L-ascorbic acid or alpha-tocopherol facilitates the development of porcine denuded oocytes from metaphase I to metaphase II and prevents cumulus cells from fragmentation.
2004,
Pubmed
Tarín,
Oral antioxidants counteract the negative effects of female aging on oocyte quantity and quality in the mouse.
2002,
Pubmed
Tarín,
Antioxidant therapy counteracts the disturbing effects of diamide and maternal ageing on meiotic division and chromosomal segregation in mouse oocytes.
1998,
Pubmed
Tashker,
Post-cytochrome C protection from apoptosis conferred by a MAPK pathway in Xenopus egg extracts.
2002,
Pubmed
,
Xenbase
Tatemoto,
Enhancement of developmental competence after in vitro fertilization of porcine oocytes by treatment with ascorbic acid 2-O-alpha-glucoside during in vitro maturation.
2001,
Pubmed
Tsuchiya,
p42MAPK-mediated phosphorylation of xEIAP/XLX in Xenopus cytostatic factor-arrested egg extracts.
2007,
Pubmed
,
Xenbase
Tsuchiya,
Apoptosis-inhibiting activities of BIR family proteins in Xenopus egg extracts.
2005,
Pubmed
,
Xenbase
von Ahsen,
Cell-free apoptosis in Xenopus laevis egg extracts.
2000,
Pubmed
,
Xenbase
Yaoita,
Induction of apoptosis and CPP32 expression by thyroid hormone in a myoblastic cell line derived from tadpole tail.
1997,
Pubmed
,
Xenbase
