Microbial, proteomic, and metabolomic profiling of the estrous cycle in wild house miceOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study mapped how oral and vaginal microbiomes change across the estrous cycle in wild house mice. Researchers used 16S rRNA sequencing of saliva and vaginal samples. They paired microbiome data with vaginal proteomics and volatile metabolomics on a subset. The goal was to link bacteria, host proteins, and odor compounds. Cytology staged each estrous phase. Data from all three platforms were integrated to test for correlated changes between microbiome and host.
Who was studied?
The animals were wild-caught adult female house mice, Mus musculus musculus, from central Bohemia, Czechia, sampled around 2018 to 2019. They were housed individually before sampling. Oral and vaginal samples were collected repeatedly over several days to capture multiple estrous phases per female. Cytology confirmed each phase. A subset of vaginal samples spanning proestrus, estrus, and metestrus underwent proteome and metabolome analysis. This OMICs subset was small.
What were the most important findings?
The vaginal microbiome changed substantially across the cycle, while the oral microbiome stayed comparatively stable. Vaginal samples showed higher bacterial diversity and greater between-animal variation than oral samples. Oral and vaginal communities shared dominant phyla but differed at the genus level. During estrus, about half the vaginal community was dominated by two genera. Estrus vaginal fluid was rich in keratinization proteins such as Hrnr, while immune proteins that limit bacterial growth (Camp, Clu, Elane, Lyz2, Ngp) were lower. Volatile ketones, aldehydes, and esters were also detected.
What are the greatest implications of this study?
The findings suggest the reproductive cycle reshapes vaginal, but not salivary, microbiota, and that these shifts move together with host proteins and odor chemicals. Lower antimicrobial proteins during estrus may permit phase-specific bacterial growth. Because the work is observational in wild mice, it describes correlations rather than proven signaling roles. The proteome and metabolome subset was small. Still, it offers a baseline for natural mouse microbiota and hints that microbes may contribute to honest chemical signals of reproductive state.