Maternal-embryo exchanges: harnessing the transcriptomic data in cattle at implantation – MEETAC

Beyond its fundamental interest, understanding the implantation process is of major importance in livestock species since the peri-implantation conceptus loss account for more than 35% of the pregnancy failure. Consequently, when pregnancy does not establish properly, repeated services (artificial inseminations or embryo transfer) are required, with a negative impact on calving intervals and a significant economical loss for livestock producers. Implantation failures are diagnosed with a few biological markers (such as progesterone and pregnancy-associated proteins) that discriminate the pregnancies failures rather late. An earlier and reliable diagnosis method for such pregnancy loss is therefore a necessity and a challenge for the dairy industry and would be promoted by the in depth investigation of the maternal-conceptus dialogue. In the last decade, high throughput transcriptomic analyses have provided major advances in the understanding of the uterine physiology (mouse, human, livestock) and of the embryo development (mouse, livestock), under physiological or pathological conditions. Integrating data from both uterine and conceptus compartments simultaneously is of major importance since the establishment and the success of this dialogue require these two parts. This proposal will thus deal with bovine reproductive physiology, aiming at a comprehensive and integrative interpretation of the gene expression profiles generated on both extra-embryonic and uterine tissues during the implantation period in cattle. As in other mammalian species, such analyses (gene expression profiling, protein expression and interactions) have not been reported yet so that this proposal looks like a real challenge to move along from genes to farming reality. A back and forth analysis will thus be required, from transcript abundances to gene networks, from genes to predictive biochemical interfaces, from in silico predictions to biological validations in experimental conditions (vitro, vivo) and ultimately from these physiological conditions to farming realities of early pregnancy loss. This last point will then critically evaluate our scientific goals in the view of a “bench to litter side” integrative approach.