Interleukin-6 Is an Essential Determinant of On-Time Parturition in the Mouse

• Published in: Endocrinology (Philadelphia) Vol. 151; no. 8; pp. 3996 - 4006
• Main Authors: Robertson, Sarah A, Christiaens, Inge, Dorian, Camilla L, Zaragoza, Dean B, Care, Alison S, Banks, Anke M, Olson, David M
• Format: Journal Article
• Language: English
• Published: United States Endocrine Society 01.08.2010
• Subjects: Animals; Animals, Newborn; Female; Gene Expression - drug effects; Gestational Age; Interleukin-6 - genetics; Interleukin-6 - metabolism; Interleukin-6 - pharmacology; Interleukin-6 - physiology; Lipopolysaccharides - pharmacology; Mice; Mice, Inbred C57BL; Mice, Knockout; Obstetric Labor, Premature - chemically induced; Obstetric Labor, Premature - genetics; Parturition - drug effects; Parturition - genetics; Pregnancy; Term Birth - drug effects; Term Birth - genetics; Time Factors; Uterine Contraction - drug effects; Uterine Contraction - genetics; Uterine Contraction - metabolism
• ISSN: 0013-7227; 1945-7170
• DOI: 10.1210/en.2010-0063

IL-6 abundance in amniotic fluid and uterine tissues increases in late gestation or with infection-associated preterm labor. A role in regulation of labor onset is suggested by observations that IL-6 increases expression of genes controlling prostaglandin synthesis and signaling in isolated uterine cells, but whether IL-6 is essential for normal parturition is unknown. To evaluate the physiological role of IL-6 in parturition in mice, we investigated the effect of Il6 null mutation on the timing of parturition and expression of genes associated with uterine activation. Il6 null mutant mice delivered 24 h later than wild-type mice, although circulating progesterone fell similarly in both genotypes during the prepartal period. Il6 null mutant mice were also refractory to low doses of lipopolysaccharide sufficient to induce preterm delivery in wild-type mice. The characteristic late-gestation elevation in uterine expression of Oxtr mRNA encoding oxytocin receptor, and peripartal increases in Ptgfr and Ptgs2 mRNAs regulating prostaglandin synthesis and signaling were delayed by 24 h in Il6 null mutant mice. Conversely, Ptger4 mRNA encoding the prostaglandin E receptor-4 was abnormally elevated in late-gestation in Il6 null mutant mice. Administration of recombinant IL-6 from d 11.5 postcoitum until term restored the normal timing of delivery and normalized Ptger4 mRNA expression in late gestation. We conclude that IL-6 has a key role in controlling the progression of events culminating in parturition and that it acts downstream of luteolysis in the uterus to regulate genes involved in the prostaglandin-mediated uterine activation cascade. The androgen receptor cofactor p44/WDR77 regulates expression of androgen receptor-target genes and is essential for the full differentiation of mouse prostate epithelial cells.