To investigate factors that can jeopardize pregnancy success in cattle, researchers at the University of São Paulo (USP) in Brazil used a kind of chip to mimic the environment of the endometrium, the tissue that lines the inside of the uterus.
The study was conducted by biologist Tiago Henrique Camara de Bem, a postdoctoral fellow at the University of São Paulo's School of Animal Science and Food Engineering (FZEA-USP), in collaboration with four researchers at the University of Leeds in the UK. Their findings are reported in an article in the journal Endocrinology.
The researchers focused on analyzing alterations in levels of insulin and glucose in maternal epithelial and stromal cells, and the possible consequences for initial development of the pregnancy. Epithelial cells are the most external in the endometrium. They interface with the lumen and are in direct contact with the embryo. Stromal cells are further inside, acting as support cells that guide epithelial cell growth, differentiation and development, among other functions.
The group discovered that high levels of glucose altered 21 protein-encoding genes in epithelial cells and 191 in stromal cells, as well as triggering quantitative changes in the protein secretome (proteins secreted in the culture medium, which in this case mimicked the endometrial fluid). "As we changed the amount of glucose and insulin in the culture medium, stressing the cells, we were able to switch genes on or off, determining whether they were or weren't expressed," Camara de Bem said.
Changes in insulin levels altered the quantitative secretion of 196 proteins but resulted in limited alteration of gene transcription. "The key factor may be the protein composition of the uterine fluid, in which these cells secrete protein into the embryo," he explained. "We found this group of proteins to be associated with signaling pathways that play an important role in early pregnancy success in cattle, relating to metabolism, cellular matrix and other factors. All these discoveries evidence a mechanism whereby maternal glucose and insulin alterations can affect uterine functioning."
Camara de Bem was supported by FAPESP via a postdoctoral fellowship for a project conducted at…