Preterm birth (PTB) is a leading worldwide cause of morbidity and mortality in infants. Maternal inflammation induced by microbial infection is a critical predisposing factor for PTB. However, biological processes associated with competency of pathogens, including viruses, to induce PTB or sensitize for secondary bacterial infection–driven PTB are unknown. We show that pathogen/pathogen-associated molecular pattern–driven activation of type I IFN/IFN receptor (IFNAR) was sufficient to prime for systemic and uterine proinflammatory chemokine and cytokine production and induction of PTB. Similarly, treatment with recombinant type I IFNs recapitulated such effects by exacerbating proinflammatory cytokine production and reducing the dose of secondary inflammatory challenge required for induction of PTB. Inflammatory challenge–driven induction of PTB was eliminated by defects in type I IFN, TLR, or IL-6 responsiveness, whereas the sequence of type I IFN sensing by IFNAR on hematopoietic cells was essential for regulation of proinflammatory cytokine production. Importantly, we also show that type I IFN priming effects are conserved from mice to nonhuman primates and humans, and expression of both type I IFNs and proinflammatory cytokines is upregulated in human PTB. Thus, activation of the type I IFN/IFNAR axis in pregnancy primes for inflammation-driven PTB and provides an actionable biomarker and therapeutic target for mitigating PTB risk.
Monica Cappelletti, Pietro Presicce, Matthew J. Lawson, Vandana Chaturvedi, Traci E. Stankiewicz, Simone Vanoni, Isaac T.W. Harley, Jaclyn W. McAlees, Daniel A. Giles, Maria E. Moreno-Fernandez, Cesar M. Rueda, Paranth Senthamaraikannan, Xiaofei Sun, Rebekah Karns, Kasper Hoebe, Edith M. Janssen, Christopher L. Karp, David A. Hildeman, Simon P. Hogan, Suhas G. Kallapur, Claire A. Chougnet, Sing Sing Way, Senad Divanovic