Signatures of receptivity

Abstract

In cattle, needed increases in the reproductive efficiency depend on a greater understanding of the endocrine, cellular and molecular mechanisms that result in higher conception rates. The central thesis of this project is that there is a "molecular signature" associated with optimal conditions of maternal receptivity to the embryo. Such signature is defined by a hallmark profile of abundance of molecules of diverse biochemical nature. The main objective is to characterize and quantify the array of molecules present in maternal tissues and fluids associated with early pregnancy and receptivity. The maternal reproductive transcriptome, proteome and lipidome will be interrogated holistically by the Systems Biology approach. In Experiment 1, the composition of uterine washings, endometrial biopsies and follicular fluid harvested on Day 6 (D6) post-insemination will be associated retrospectively with the gestational success measured on D30 in the same animals. In Experiment 2, the peri-ovulatory endocrine milieu will be modulated to result in progesterone concentrations post-estrus that are greater (associated with greater fertility) or lower (reduced fertility). Molecular composition of washings and tissues of the oviduct (harvested on D4) and the endometrium (harvested on D7) will be compared between groups. Molecules showing differential abundances between experimental groups will define molecular signatures associated with the greater or smaller probability of gestational success; the placement of such molecules in the context of metabolic pathways will allow definition of mechanisms potentially controlling gestational success; moreover, such molecules may be used as markers of gestational success. New knowledge will provide background to the development of technologies. Success of the present project is guaranteed by the integrated work of specialists skillful in each analytical procedure and by the infrastructure of the collaborating institutions. (AU)