Neisseria gonorrhoeae Survival during Primary Human Cervical Epithelial Cell Infection Requires Nitric Oxide and Is Augmented by Progesterone

Abstract

Neisseria gonorrhoeae is an obligate human pathogen that causes gonorrhea. We have shown previously that complement receptor 3 and Akt kinase play important roles in mediating cervical infection. At present, there are limited data to indicate how hormonally induced changes to the mucosal epithelia of the female genital tract mediate the course of gonococcal disease. Hence, I have expanded upon previous work to investigate the interaction of gonococci with primary human cervical epithelial (pex) cells under the variable estrogen and progesterone concentrations likely to be encountered in vivo throughout the female menstrual cycle. My data indicated that the ability of gonococci to survive and to replicate within pex cells was increased under progesterone-predominant conditions. Using bacterial survival, immunological, and kinase assays, I show that progesterone functioned in an additive manner with gonococcal phospholipase D to augment Akt kinase activity. This, in turn, resulted in a parallel increase in nitric oxide synthase expression. Nitric oxide production by pex cells was dependent upon Akt activity and was increased under progesterone-predominant conditions. Whereas both inducible and endothelial nitric oxide synthase contributed to nitric oxide production, only inducible nitric oxide synthase activity promoted gonococcal survival within pex cells. Collectively, these data provide the first clues as to how steroid hormones potentially modulate the course of gonococcal disease in women. In addition, these data demonstrate that host-derived nitric oxide likely is not protective against gonococci, in vivo; rather, nitric oxide may be required to sustain cervical bacterial disease.