Endoplasmic Reticulum (ER) Stress and Apoptosis in Parthenogenetic Porcine Embryos following Different Combination of Activation Methods

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We investigated the effects of endoplasmic reticulum (ER) stress inhibitor and antioxidant treatments during the micromanipulation of somatic cell nuclear transfer (SCNT) on in vitro development of SCNT embryos. Tauroursodeoxycholic acid (TUDCA), an ER stress inhibitor and vitamin C (Vit. C), an antioxidant, were treated by alone or in combination, then, the level of X-box binding protein 1 (Xbp1) splicing and the expressions of ER stress-associated genes, oxidative stress-related genes, and apoptotic genes were confirmed in the 1-cell and blastocyst stages. In the 1-cell stage, the levels of Xbp1 splicing were significantly decreased in TUDCA and Vit. C treatment groups compared to the control (p<0.05). In addition, the expression levels of most ER stress-associated genes and oxidative stress-related genes were significantly lower in all treatment groups than the control (p<0.05), and the transcript levels of apoptotic genes were also significantly lower in all treatment groups than the control (p<0.05). In the blastocyst stage, decreased expression of ER stress-, oxidative stress-, and apoptosis-related genes were observed only in some treatments. However, the blastocyst formation rates in TUDCA and Vit. C treatment groups (24.8% and 22.0%, respectively) and mean blastocyst cell number in all treatment groups (59.7±4.3 to 63.5±3.3) were significantly higher (p<0.05) than those of control. The results showed that the TUDCA or Vit. C treatment during micromanipulation inhibited both ER and oxidative stresses in the early stage of SCNT embryos, thereby reducing cell damage and promoting in vitro development.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Endoplasmic Reticulum (ER) Stress Inhibitor or Antioxidant Treatments during Micromanipulation Can Inhibit Both ER and Oxidative Stresses in Porcine SCNT Embryos

Park¹,

Park²,

Kim³

et al. 2020

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“…It activates apoptosis by increasing the expression of pro-apoptotic protein Bax and caspase-3 ( Song, 2012 ; Sano & Reed, 2013 ). In the previous study, ER stress and apoptosis according to the activation method of porcine parthenogenetic embryos were analyzed, and it was confirmed that ER stress generation and apoptosis were increased in the treated with A23187 ( Park et al, 2017 ).…”

Section: Discussionmentioning

confidence: 75%

“…Contrastively ER stress inhibitor decreased the expression of GRP94, ATF4 and apoptotic genes in the EC group at the 1-cell stage. It is suggested that ER stress inhibitor can reduce the ER stress and apoptosis of parthenogenetic embryos induced by A23187 ( Park et al, 2017 ).…”

Section: Discussionmentioning

confidence: 99%

“…Under ER stress conditions in SCNT embryos, embryonic metabolism degeneration and apoptosis by embryo fragmentation can occur ( Zhang et al, 2011 ; Lee et al, 2018 ). In the previous experiment, the generation of ER stress according to the activation method of embryo was confirmed, and it was occurred that the high levels of ER stress and cell damage in the treatment of Ca-ionophore (A23187) after ES ( Park et al, 2017 ).…”

Section: Introductionmentioning

confidence: 89%

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Effect of Endoplasmic Reticulum (ER) Stress Inhibitor Treatment during Parthenogenetic Activation on the Apoptosis and In Vitro Development of Parthenogenetic Porcine Embryos

Park¹,

Kim²,

Jung³

et al. 2018

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We investigate the effect of endoplasmic reticulum (ER) stress inhibitor treatment during parthenogenetic activation of oocytes on the ER stress generation, apoptosis, and in vitro development of parthenogenetic porcine embryos. Porcine in vitro matured oocytes were activated by 1) electric stimulus (E) or 2) E+10 μM Ca-ionophore (A23187) treatment (EC). Oocytes were then treated by ER stress inhibitors such as salubrinal (200 nM) and tauroursodeoxychloic acid (TUDCA, 100 μM) for 3 h prior to in vitro culture. Parthenogenetic embryos were sampled to analyze ER stress and apoptosis at the 1-cell and blastocyst stages. The x-box binding protein 1 (Xbp1) mRNA and ER stress-associated genes were analyzed by RT-PCR or RT-qPCR. Apoptotic gene expression was analyzed by RT-PCR. At the 1-cell stage, although no difference was observed in Xbp1 splicing among treatments, BiP transcription level in the E group was significantly reduced by salubrinal treatment, and GRP94 and ATF4 transcription levels in EC group were significantly reduced by all treatments (p<0.05) compared to control. In the EC group, both apoptotic genes were reduced by ER stress inhibitor treatments compared to control (p<0.05) except Caspase-3 gene by TUDCA treatment. These results suggest that the treatment of ER stress inhibitor during parthenogenetic activation can reduce ER stress, and thereby reduce apoptosis and promote in vitro development of porcine parthenogenetic embryos.

Effects of Endoplasmic Reticulum Stress Inhibitor Treatment during the Micromanipulation of Somatic Cell Nuclear Transfer in Porcine Oocytes

Park

Kim

et al. 2019

Self Cite

We examined the effects of endoplasmic reticulum (ER) stress inhibitor treatment during the micromanipulation of porcine somatic cell nuclear transfer (SCNT) on the in vitro development of SCNT embryos. ER stress inhibitors such as salubrinal (200 nM) and tauroursodeoxycholic acid (TUDCA; 100 μM) were added to the micromanipulation medium and holding medium. The expression of X-box binding protein 1 ( Xbp1 ), ER-stress-associated genes, and apoptotic genes in SCNT embryos was confirmed at the one-cell and blastocyst stages. Levels of Xbp1 splicing and expression of ER-stress-associated genes in SCNT embryos at the one-cell stage decreased significantly with TUDCA treatment ( p <0.05). The expression of ER-stress-associated genes also decreased slightly with the addition of both salubrinal and TUDCA (Sal+TUD). The expression levels of caspase-3 and Bcl2-associated Xprotein ( Bax ) mRNA were also significantly lower in the TUDCA and Sal+TUD treatments ( p <0.05). At the blastocyst stage, there were no differences in levels of Xbp1 splicing, and transcription of ER-stress-associated genes and apoptosis genes between control and treatment groups. However, the blastocyst formation rate (20.2%) and mean blastocyst cell number (63.0±7.2) were significantly higher ( p <0.05) for embryos in the TUDCA treatment compared with those for control (12.6% and 41.7±3.1, respectively). These results indicate that the addition of ER-stress inhibitors, especially TUDCA, during micromanipulation can inhibit cellular damage and enhance in vitro development of SCNT embryos by reducing stress levels in the ER.