Metabolite expression profiles of vaginal microbial organisms associated with inflammation-induced preterm birth.

Purpose/aims: This studentship will further explore intriguing observations from a recently concluded studentship and MRC DPFS-funded study that identified unique microbial and metabolite signature profiles of cohorts of pregnant women at varying risk of spontaneous preterm birth. Using female genital tract cell lines as well as primary cells obtained from women, metabolite responses and profiles to common vaginal pathogenic (associated with preterm birth, PTB) and commensal (maintains the healthy vaginal milieu) bacteria will be established in order to clarify how they promote cervico-vaginal health (biosis) or infection/inflammation (dysbiosis), particularly in respect of the mechanisms of inflammation-associated preterm birth during human pregnancy, and its prediction.

Background: Changes in vaginal microbiota that are associated with preterm birth (PTB) leave specific microfloral and metabolite fingerprints that can be detected in the cervicovaginal fluid (CVF) using microbiomics and metabolomics techniques. We have recently characterized and validated the CVF metabolite profile of pregnant women presenting with symptoms of threatened preterm labor (PTL), as well as asymptomatic women at risk of preterm birth by both 1H-nuclear magnetic resonance spectroscopy (NMR) and enzyme-based spectrophotometry. We have also determined their predictive capacity for PTB, singly, and in combination, with current clinical screening tools - cervicovaginal fetal fibronectin (FFN) and ultrasound cervical length (CL)[PMID: 27777928; PMID: 27065760]. For instance, we reported and validated that acetate integrals were higher in women destined to deliver preterm, and within 2 weeks of the index assessment, than those who delivered at term. We have also recently shown that specific vaginal microbial community state types are associated with differing expression levels of some study metabolites, as well as with preterm birth. This studentship will seek to explore in greater detail the differences in metabolite expression levels and patterns between different vaginal microbes, commensals which promote vaginal health (eg lactobacillus) and those which are associated with vaginosis (eg bacterial vaginosis organisms), sepsis and inflammation.

The student will carry out in vitro co-culture (infection) experiments - employing commercially available commensal and infective bacteria and vaginal epithelial, cervical epithelial and HeLa cell lines, employing well described protocols employed within the group. The student will acquire skills in cell culture, GC mass spectrometry, spectrophotometry, H-Nuclear Magnetic Resonance spectroscopy, next-generation 16s pyrosequencing microbiome profiling, as well as relevant molecular biological techniques. The project experiments will shed light on mechanisms of microbial metabolism in the female reproductive tract, and may uncover new potential biomarkers of vaginal infection and inflammation-associated preterm birth. Several publication and presentation outputs are envisaged and the student will be encouraged and supported to achieve these aims.