Involvement of the JAK-STAT pathway in collagen regulation of decidual NK cells.

PROBLEM: The mechanisms underlying the regulation of decidual natural killer cells (dNKs) at the maternal-fetal interface are unclear.

METHOD OF STUDY: Primary trophoblasts (TROs), decidual stromal cells (DSCs), and dNKs were cocultured, and responses to LAIR-2 (LAIR-1 inhibitor) and P4H shRNA (collagen inhibitor) were studied.

RESULTS: Coculture of dNKs with primary TROs/DSCs resulted in downregulation of Th1 cytokine production by dNKs. These effects were abrogated by LAIR-2 and P4H shRNA. LAIR-1 binds to SHP-1, which in turn binds to JAK1 and JAK2. Further, the phosphorylation of STAT1/STAT4 and the expression of the downstream transcription factors T-bet and Helios in dNKs were decreased by collagen treatment and primary TROs/DSCs coculture.

CONCLUSION: The JAK-STAT pathway and its downstream transcription factors T-bet and Helios are involved in the regulation of dNK function by collagen/LAIR-1 interaction, and this signaling mechanism may contribute to the maintenance of immune tolerance at the maternal-fetal interface.