Mendoza, N. | Search bioRxiv

bioRxiv2022

Impact of pregravid obesity on anti-microbial fetal monocyte response

Maternal pre-pregnancy (pregravid) obesity is associated with adverse outcomes for both mother and offspring. Amongst the complications for the offspring is increased susceptibility and severity of neonatal infections necessitating admission to the intensive care unit, notably bacterial sepsis and enterocolitis. Previous studies have reported aberrant responses to LPS and polyclonal stimulation by umbilical cord blood monocytes that were mediated by alterations in the epigenome. In this study, we show that pregravid obesity dysregulates umbilical cord blood monocyte responses to bacterial and viral pathogens. Specifically, interferon-stimulated gene expression and inflammatory responses to E. coli and respiratory syncytial virus (RSV) were significantly dampened. Although upstream signaling events were comparable, translocation of the key transcription factor NF-{kappa}B and chromatin accessibility at pro- inflammatory gene promoters following TLR stimulation was significantly attenuated. Using a rhesus macaque model of western style diet induced obesity, we further demonstrate that this defect is detected in fetal peripheral monocytes and tissue-resident macrophages during gestation. Collectively, these data indicate that maternal obesity and high-fat diet present metabolic, signaling, and epigenetic impediments to pathogen recognition in fetal innate immune cells that result in a state of immune paralysis during gestation and at birth.

immunology↗

bioRxiv2020

Functional and genomic adaptations of blood monocytes to pregravid obesity during pregnancy

Pre-pregnancy obesity is associated with several adverse maternal health outcomes, notably increased risk of infection as well as the incidence of gestational diabetes, preeclampsia, and preterm birth. However, the mechanisms by which pregravid obesity disrupts the pregnancy associated "immune clock" are still unknown. To address this question, we collected blood samples from women during the first and third trimesters and determined the impact of both pregnancy and pregravid obesity on circulating immune mediators, immune cell subset frequencies, and peripheral immune responses. While regardless of BMI, pregnancy was associated with an elevation in both Th1 and Th2 cytokines, pregravid obesity was associated with a dysregulation in circulating myeloid factors at term. Moreover, pregnancy in lean subjects was associated with enhanced monocyte activation, augmented chromatin accessibility at inflammatory loci, and heightened responses to LPS. Pregravid obesity disrupted this trajectory and was accompanied by a lack of transcriptional and epigenetic changes and alterations in metabolic status strongly suggesting a skewing towards immunotolerance. These findings provide novel insight into the increased susceptibility to infections observed with obesity during pregnancy. SUMMARYA healthy pregnancy is associated with progressive innate immune activation. Maternal factors such as obesity compromise this myeloid cell activation trajectory at genomic, epigenomic, functional, and metabolic levels, resulting in stagnant immune responses, suggestive of a state of tolerance.

immunology↗