Sex-Dependent Relationships Between PFAS and Placental Transcriptomics Identified by Weighted Gene Co-Expression Analysis

Background Per– and polyfluoroalkyl substances (PFAS) are environmental toxicants associated with adverse neonatal outcomes. The exact mechanisms by which PFAS impairs neonatal health are undefined, but the placenta is a likely target.

We applied a systems biology approach to identify placental RNA co-expression modules (gene sets) associated with PFAS exposure and birth weight.

Placental tissue samples (n = 147) from the GLOWING study underwent RNA-sequencing, and PFAS concentrations were quantified using liquid chromatography-tandem mass spectrometry. We constructed a weighted gene co-expression network using Spearman correlations across 15,028 transcripts, identifying 20 gene modules. Linear regression models were used to examine associations between PFAS and module eigengenes, adjusting for potential confounders. Effect modification by fetal sex was also tested.

One module showed a negative association with perfluorononanoic acid (PFNA; β = – 0.012, q = 0.009). This association was sex-specific, with the sexes exhibiting varied PFAS associations but similar directional effects. Genes within the PFNA-associated module were involved in histone modification (q ≤ 0.05) and were enriched for targets of the Vitamin D Receptor (VDR), a transcription factor previously linked to PFAS.

Our research indicates that prenatal exposure to PFNA influences placental gene expression differently based on sex, which may affect insulin growth factor signaling and histone modification. The presence of VDR in this module and the transcription enrichment analysis align with previous findings regarding PFAS and VDR interactions. This module related to PFNA could shed light on the molecular pathways connecting PFAS exposure to health outcomes in neonates. Competing Interest Statement The authors have declared no competing interest. Funding Statement This work was supported by funding from the National Institute of Environmental Health Sciences, NIH/NIEHS [R01 ES032176; MPIs: Andres, Everson, & Pearson], NIH/NIEHS [R01 ES036986; MPIs: Andres & Everson], the HERCULES Center [P30 ES019776; MPIs: Everson, Barr], the UK-CARES Center [P30 ES026529; CoI: Pearson], and a NIEHS training grant [5T32ES012870] which supports CP. KS is supported by USDA ARS CRIS 3093-51000-001-00D. Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the views of NIH or the USDA. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Ethics Committee/IRB of Emory University gave ethical approval for this work. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Footnotes Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper Funding statement: This work was supported by funding from the National Institute of Environmental Health Sciences, NIH/NIEHS [R01 ES032176; MPIs: Andres, Everson, & Pearson], NIH/NIEHS [R01 ES036986; MPIs: Andres & Everson], the HERCULES Center [P30 ES019776; MPIs: Everson, Barr], the UK-CARES Center [P30 ES026529; CoI: Pearson], and a NIEHS training grant [5T32ES012870] which supports CP. KS is supported by USDA ARS CRIS 3093-51000-001-00D. Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the views of NIH or the USDA Data Availability All data produced in the present study are available upon reasonable request to the authors.