Understanding somatic cell characteristics to improve embryo developmental potential in vitro

经过20多年的研究，非家种离体胚胎技术的实施进展有限。研究材料供应不足是进展缓慢的主要原因；然而，物种间的差异（如季节性、发育速度）对繁殖后代构成了挑战。此外，目前储存在世界各地生物银行的遗传物质主要由冷冻精子组成。获得和冷冻保存卵母细胞和胚胎的困难限制了这些生物库中女性遗传学的比例。我们对野牛（bison bison）的研究证实了该物种的卵母细胞处理和培养的复杂性，该物种的卵母细胞成熟度低，体外胚胎发育率低，使用标准的家养牛方案。最近，国际自然保护联盟（IUCN）呼吁将所有濒危物种的细胞储存起来，以便在遗传物质丢失之前将其保存下来。这一呼吁引起了人们对体细胞储存的兴趣，并在世界范围内启动了体细胞库。其中一个主要原因是体细胞的重编程能力及其对未来后代生产的潜在用途。我们的研究表明，样品收集和培养建立技术影响成纤维细胞的培养特性，包括染色体数目和端粒长度。此外，成纤维细胞培养的个体差异在体细胞核移植（SCNT）后的着床前胚胎发育中发挥了重要作用，尽管这些差异的原因尚未阐明。为了利用体细胞技术（如SCNT）改善胚胎的产生，有必要更好地了解供体细胞的遗传和表观遗传组成，以确定并潜在地修改调节胚胎存活的因素。我们的研究兴趣在于了解细胞因素对种间SCNT胚胎早期发育的影响，以提高其在生产遗传价值动物中的潜在应用。该研究将确定成人体细胞中可能指示SCNT成功的因素，并检查供体细胞的修饰是否可以促进适当的重编程并提高早期胚胎的活力和质量。在研究的第一阶段，木野牛供体细胞的特征将用于将细胞参数与种间SCNT成功联系起来。在第二阶段，将在SCNT之前对野牛供体细胞进行修饰，以评估其对囊胚发育的影响。这项研究将增加我们对胚胎活力和质量的细胞决定因素的理解，并为我们改善家养和非家养物种的SCNT结果提供潜在的方法。

After more than 20 years of research, there has been limited progress in the implementation of in vitro embryo technologies for non-domestic species. Insufficient supply of materials for research purposes plays a major role in the slow progress; however, species-specific differences (e.g. seasonality, rates of development) contribute to the challenges of producing offspring. In addition, genetic material currently stored in biobanks around the world consists primarily of frozen sperm. Difficulties in obtaining and cryopreserving oocytes and embryos have limited the proportion of female genetics represented in these biobanks. Our studies in bison (Bison bison) have confirmed the complexities of oocyte handling and culture in this species with low oocyte maturation and in vitro embryo development rates using standard domestic cattle protocols. A recent call to action from the International Union for the Conservation of Nature (IUCN) for the banking of cells from all threatened species to preserve genetic material before it is lost has resulted in an increased interest in somatic cell banking and the initiation of somatic cell banks around the world. One of the primary reasons is the reprogramming capability of somatic cells and their potential use for future offspring production. Our studies have shown that sample collection and culture establishment techniques influenced fibroblast culture characteristics, including chromosome number and telomere length. Furthermore, individual variability in the fibroblast cultures played a significant role in pre-implantation embryo development following somatic cell nuclear transfer (SCNT), although the reason for these differences was not elucidated. In order to improve embryo production using somatic cell-based techniques, such as SCNT, a better understanding of the genetic and epigenetic make-up of the donor cells is necessary to identify, and potentially modify, factors regulating embryo survival. Our research interest lies in understanding the influence of cellular factors on early development of interspecies SCNT embryos to improve its potential use in the production of genetically valuable animals. The proposed research will identify factors in adult somatic cells that may be indicative of SCNT success and examine whether modification of the donor cells can promote proper reprogramming and enhance early embryo viability and quality. In the first phase of the study, characterization of wood bison donor cells will be used to correlate cell parameters with interspecies SCNT success. In the second phase, modification of bison donor cells will be carried out prior to SCNT to evaluate their influence on blastocyst development. This study will increase our understanding of cellular determinants of embryo viability and quality and provide us with potential methods for improving SCNT outcomes in both domestic and non-domestic species.