Cell synchronization by Rapamycin improves the developmental competence of buffalos (Bubalus bubalis) somatic cell nuclear transfer embryos

Enhancing the quality of inferior oocytes of buffalo for in vitro embryo production: The impact of melatonin on maturation, SCNT, and epigenetic modifications

Success of animal cloning is limited by oocyte quality, which is closely linked to reprogramming ability. The number of layers of cumulus cells is typically used to assess the quality of oocyte; a minimum of one-third of collected cumulus-oocyte complexes (COCs) are discarded as inferior oocytes because they have less cumulus cells. Melatonin, which has been recognised for its ability to sequester free radicals and perform multiple functions, has emerged as a potentially effective candidate for enhancing inferior oocytes quality and, consequently, embryo development competency. The current study investigates to improve the quality of inferior oocytes by supplementation of melatonin (10-9 M) during in vitro maturation (IVM) and subsequent cloned embryo production and its mechanism. The results indicate that melatonin supplementation significantly (p<0.05) enhances inferior oocytes maturation, reduces oxidative stress by reducing ROS levels, and improves mitochondrial function by boosting GSH levels. The melatonin treatment (10-9 M) enhances the expression of SOD, GPx1, GDF 9, BMP 15, ATPase 6, and ATPase 8 in inferior oocytes. Furthermore, melatonin treatment increases the total cell number in the treated groups, promoting cloned blastocyst formation rates derived from inferior oocytes. Furthermore, compared to the control, 10-9 M melatonin supplementation enhances H3K9ac acetylation and lowers H3K27me3 methylation in cloned blastocysts derived from inferior oocytes. In conclusion, 10-9 M melatonin supplementation during IVM increased inferior oocyte maturation and promoted cloned buffalo embryo development by lowering oxidative stress and promoting epigenetic alterations. These studies show that melatonin may improve the quality of poor oocytes and buffalo cloning.

Vitamin C down-regulates the H3K9me3-dependent heterochromatin in buffalo fibroblasts via PI3K/PDK1/SGK1/KDM4A signal axis

The success of reprogramming is dependent on the reprogramming factors enriched in the cytoplasm of recipient oocytes and the potential of donor nucleus to be reprogrammed. Histone 3 lysine 9 trimethylation (H3K9me3) was identified as a major epigenetic barrier impeding complete reprogramming. Treating donor cell with vitamin C (Vc) can enhance the developmental potential of cloned embryos, but the underlying mechanisms still need to be elucidated. In this study, we found that 20μg/mL Vc could promote proliferation and inhibit apoptosis of BFFs, as well as down-regulate the H3K9me3-dependent heterochromatin and increase chromatin accessibility. Inhibited the expression of KDM4A resulted in increasing apoptosis rate and the H3K9me3-dependent heterochromatin, which can be restored by Vc. Moreover, Vc up-regulated the expression of KDM4A through PI3K/PDK1/SGK1 pathway. Inhibiting any factor in the signal axis of this PI3K pathway not only suppressed the activity of KDM4A but also substantially increased the level of H3K9me3 modification and the expression of the HP1α protein. Finally, Vc can rescue those negative effects induced by the blocking the PI3K/PDK1/SGK1 pathway. Collectively, Vc can down-regulate the H3K9me3-dependent heterochromatin in BFFs via PI3K/PDK1/SGK1/KDM4A signal axis, suggesting that Vc can turn the chromatin status of donor cells to be reprogrammed more easily.

Molecular Mechanism of Overcoming Host Resistance by the Target of Rapamycin Gene in Leptographium qinlingensis

Leptographium qinlingensis is a fungal symbiont of the Chinese white pine beetle (Dendroctonus armandi) and a pathogen of the Chinese white pine (Pinus armandii) that must overcome the terpenoid oleoresin defenses of host trees to invade and colonize. L. qinlingensis responds to monoterpene flow with abundant mechanisms that include the decomposing and use of these compounds as a nitrogen source. Target of Rapamycin (TOR) is an evolutionarily conserved protein kinase that plays a central role in both plants and animals through integration of nutrients, energies, hormones, growth factors and environmental inputs to control proliferation, growth and metabolism in diverse multicellular organisms. In this study, in order to explore the relationship between TOR gene and carbon sources, nitrogen sources, host nutrients and host volatiles (monoterpenoids) in L. qinlingensis, we set up eight carbon source treatments, ten nitrogen source treatments, two host nutrients and six monoterpenoids (5%, 10% and 20%) treatments, and prepared different media conditions. By measuring the biomass and growth rate of mycelium, the results revealed that, on the whole, the response of L. qinlingensis to nitrogen sources was better than carbon sources, and the fungus grew well in maltose (carbon source), (NH₄)₂C₂O₄ (inorganic nitrogen source), asparagine (organic nitrogen source) and P. armandii (host nutrient) versus other treatments. Then, by analyzing the relationship between TOR expression and different nutrients, the data showed that: (i) TOR expression exhibited negative regulation in response to carbon sources and host nutrition. (ii) The treatments of nitrogen sources and terpenoids had positively regulatory effects on TOR gene; moreover, the fungus was most sensitive to β-pinene and 3-carene. In conclusion, our findings reveal that TOR in L. qinlingensis plays a key role in the utilization of host volatiles as nutrient intake, overcoming the physical and chemical host resistances and successful colonization.