Bovine interferon-τ stimulates the Janus kinase-signal transducer and activator of transcription pathway in bovine endometrial epithelial cells

Trophoblastic bovine interferon-tau (blFN-tau) suppresses luteolytic pulses of endometrial prostaglandin F-2 alpha (PGF(2 alpha)) at the time of maternal recognition of pregnancy. This results in maintenance of the corpus luteum in cattle. The hypothesis that effects of blFN-tau in the endometrium were through activation of the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway of signal transduction was tested. Whole cell, cytosolic, and nuclear extracts from bovine endometrial cells treated with blFN-tau were analyzed by immunoprecipitation, immunoblotting, and electrophoretic mobility shift assays in a series of dose- and time-dependency experiments. Bovine IFN-tau stimulated tyrosine phosphorylation, homo- and heterodimer formation, nuclear translocation, and DNA binding of STAT proteins 1, 2, and 3, Moreover, blFN-tau induced synthesis of interferon-regulatory factor. In conclusion, blFN-tau stimulates the JAK-STAT pathway in the bovine endometrium. It is proposed that activation of the JAK-STAT pathway is involved in regulating the antiluteolytic effects of blFN-tau.