Bovine Interferon-τ Stimulates the Janus Kinase-Signal Transducer and Activator of Transcription Pathway in Bovine Endometrial Epithelial Cells1

Abstract

Trophoblastic bovine interferon-tau (bIFN-τ) suppresses luteolytic pulses of endometrial prostaglandin F_2α (PGF_2α) at the time of maternal recognition of pregnancy. This results in maintenance of the corpus luteum in cattle. The hypothesis that effects of bIFN-τ 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 bIFN-τ were analyzed by immunoprecipitation, immunoblotting, and electrophoretic mobility shift assays in a series of dose- and time-dependency experiments. Bovine IFN-τ stimulated tyrosine phosphorylation, homo- and heterodimer formation, nuclear translocation, and DNA binding of STAT proteins 1, 2, and 3. Moreover, bIFN-τ induced synthesis of interferon-regulatory factor. In conclusion, bIFN-τ 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 bIFN-τ.