Developmental programming: Sex-specific effects of prenatal exposure to a real-life mixture of environmental chemicals on liver function and transcriptome in sheep

Soundara Viveka Thangaraj; Michelle Bellingham; Richard Lea; Neil Evans; Kevin Sinclair; Vasantha Padmanabhan

doi:10.1016/j.envpol.2025.125630

Developmental programming: Sex-specific effects of prenatal exposure to a real-life mixture of environmental chemicals on liver function and transcriptome in sheep

Environ Pollut. 2025 Jan 3:367:125630. doi: 10.1016/j.envpol.2025.125630. Online ahead of print.

Authors

Soundara Viveka Thangaraj¹, Michelle Bellingham², Richard Lea³, Neil Evans², Kevin Sinclair³, Vasantha Padmanabhan¹

Affiliations

¹ Department of Pediatrics, University of Michigan, Ann Arbor, MI, USA.
² School of Biodiversity One Health and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, UK.
³ Schools of Biosciences and Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.

PMID: 39756566
DOI: 10.1016/j.envpol.2025.125630

Abstract

Humans are chronically exposed to a mixture of environmental chemicals (ECs), many with metabolic and endocrine disrupting potential, contributing to non-communicable disease burden. Understanding the effects of chronic exposure to low-level mixtures of ECs requires an animal model that reflects real-world conditions, lags behind studies on single ECs. Biosolids, from wastewater treatment, offers a real-life model to investigate the developmental health risks from EC mixtures. Prenatal biosolids exposure studies have documented metabolic perturbations including heavier thyroid glands in male fetuses and reduced bodyweight in prepubertal male lambs followed by catchup growth. We hypothesized that maternal preconceptional and gestational exposure of sheep to biosolids programs sex-specific transcriptional and functional changes in the offspring liver. Ewes (F0) were grazed on either inorganic fertilizer (C) or biosolids-treated pastures (BTP) preconception till parturition. All lambs (n = 15/group with male n = 7/group and females n = 8/group) were raised on Control pastures until euthanasia at 9.5 weeks. Next generation sequencing of liver RNA and DESeq2 was used to identify exposure-specific differentially expressed genes (DEG) and sex-differentially expressed genes (SDG). Liver function was assessed with markers of oxidative stress, triglyceride and fibrosis markers. Control lambs exhibited 647 SDGs confirming the inherent sexual dimorphism in hepatic gene expression. A sex-stratified analysis identified 10 DEG, mostly affecting metabolism, in male and none in female lambs. Biosolids exposure diminished the sexual dimorphism in hepatic gene expression barring 41 genes, potentially due to the increase in androgenic steroids found in F0 maternal circulation. Additionally, BTP male lambs showed elevated plasma triglyceride and a trend towards increased liver triglyceride concentrations. The identified effects of prenatal exposure to low-dose mixture of ECs via biosolids, in a precocial species paralleling human developmental patterns holds translational importance for understanding the sexually dimorphic origin of non-communicable diseases.

Keywords: Biosolids; Endocrine disrupting chemicals; Liver; Sexual dimorphism.

Grants and funding

R01 ES030374/ES/NIEHS NIH HHS/United States