Proteomic Characterization
of Histotroph during the
Preimplantation Phase of the Estrous Cycle in Cattle
- Publication date
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Abstract
Uterine secretions, or histotroph, are a critical component
for
early embryo survival, functioning as the sole supply of vitamins,
minerals, enzymes, and other myriad of nutrients required by the developing
conceptus before implantation. Histotroph is therefore a promising
source for biomarkers of uterine function and for enhancing our understanding
of the environment supporting early embryo development and survival.
Utilizing label-free liquid chromatography–tandem mass spectrometry
(LC–MS/MS) shotgun proteomics, we characterized the uterine
proteome at two key preimplantation stages of the estrous cycle in
high fertility cattle. We identified 300 proteins on Day 7 and 510
proteins on Day 13 including 281 proteins shared between days. Five
proteins were more abundant (<i>P</i> < 0.05) on Day
7 compared with Day 13 and included novel histotroph proteins cytokeratin
10 and stathmin. Twenty-nine proteins were more abundant (<i>P</i> < 0.05) including 13 unique on Day 13 compared with
Day 7 and included previously identified legumain, metalloprotease
inhibitor-2, and novel histotroph proteins chromogranin A and pyridoxal
kinase. Functional analysis of the 34 differentially expressed proteins
(including 14 novel to histotroph) revealed distinct biological roles
putatively involved in early pregnancy, including remodelling of the
uterine environment in preparation for implantation; nutrient metabolism;
embryo growth, development and protection; maintenance of uterine
health; and maternal immune modulation. This study is the first reported
LC–MS/MS based global proteomic characterization of the uterine
environment in any domesticated species before implantation and provides
novel information on the temporal alterations in histotroph composition
during critical stages for early embryo development and uterine function
during the early establishment of pregnancy