Pregnancy specific shifts in the maternal microbiome and metabolome in the BPH5 mouse model of superimposed preeclampsia

Preeclampsia (PE) is a life-threatening hypertensive disorder of pregnancy with an incidence rate of up to 8% worldwide. However, the complete pathogenesis is still unknown. Obesity increases the risk of developing PE three-fold. To better understand the relationship of maternal risk factors, the BPH/5 mouse was described as a model of superimposed PE. Previous research demonstrated that adult BPH/5 female mice have an adverse cardiometabolic phenotype characterized by hypertension, obesity with increased white adipose tissue and dyslipidemia, exaggerated by pregnancy. We hypothesize that BPH/5 mice have gut dysbiosis characterized by changes in alpha and beta diversity of bacterial community structure as well as perturbed short chain fatty acids (SCFA) compared to controls in pregnancy. Fecal samples were used for Illumina sequencing of 16S v4 rRNA amplicons. Microbial community composition of the pregnant BPH/5 compared to C57 controls was different using PERMANOVA with Bray-Curtis dissimilarity. Alpha diversity was increased in pregnant BPH/5 dams compared to controls. Alistipes and Helicobacter were increased while Bacteroides, Lactobacillus, Parasulterrella, and Parabacteroides were decreased compared to controls. Fecal SCFAs were not different between groups, but BPH/5 serum acetic and butyric acid were decreased while isobutyric and isovaleric acid were increased specifically in pregnancy. BPH/5 pregnant colons had decreased expression of free fatty acid receptor, GPR41. In conclusion, the BPH/5 maternal fecal microbiome demonstrates microbial dysbiosis characterized by community structure and diversity changes before and after the onset of pregnancy. Gut dysbiosis may be a key mechanism linking SCFA signaling and obesity to the BPH/5 PE-like phenotype.