Transcriptomic analysis defines gestation-specific programs of fetal liver maturation in premature sheep

Abstract

Fetal liver maturation is essential for postnatal metabolic, synthetic, detoxification, and immune function. Disruption of this process by preterm birth contributes to hypoglycemia, impaired detoxification, and immune immaturity. However, the transcriptional programs associated with hepatic maturation during mid-to-late gestation remain incompletely defined. We addressed this gap using a translationally relevant ovine model. Bulk RNA sequencing was performed on ovine fetal livers collected at gestational days 100, 124, and 144 (term = 150 days). Differential expression analysis, F-test–based temporal trajectory analysis, gene set variation analysis (GSVA), and weighted gene co-expression network analysis (WGCNA) were integrated to characterize gestational transcriptional programs, pathway dynamics, and regulatory networks. Global transcriptomic profiles segregated according to gestational age. Independent gene-, pathway-, and network-level analyses demonstrated highly concordant gestational age-associated transcriptional patterns characterized by increased representation of metabolic, biosynthetic, detoxification, complement/coagulation, and mitochondrial pathways in later gestational groups, together with reduced representation of proliferative and cell cycle–related programs. Network analysis highlighted candidate regulators of hepatic developmental transcriptional programs, including STAT3, HNF4G, CEBPB, KLF6, NR3C1, RORA, NFKB1, and ATF6, associated with metabolic, immune, and stress-responsive pathways. These findings provide a systems-level transcriptomic reference of fetal liver development across gestation and a framework for investigating how perinatal conditions and therapeutic interventions influence hepatic developmental programs, which are difficult to study directly in human fetuses because of limited access to fetal liver tissue.