Multicellular state transitions and signaling rewiring during the proestrus-to-estrus switch in the porcine ovary

The porcine ovary undergoes rapid multicellular remodeling during the transition from proestrus to estrus, but the cell type–specific transcriptional programs associated with this process remain incompletely defined. Here, we aimed to resolve stage-dependent cellular states and intercellular signaling events in the porcine ovary across proestrus and estrus at single-cell resolution. We generated a stage-resolved single-nucleus RNA sequencing atlas of porcine ovaries spanning proestrus and estrus. Integrative analyses of granulosa cell heterogeneity, metabolic pathway activity, and inferred metabolic flux highlighted ERBB4 and the glutamine transporter SLC1A5 as candidate stage-associated factors during the proestrus-to-estrus transition. By combining cell type–specific differential expression profiling with intercellular communication network analysis across major ovarian somatic compartments, we further identified TGF-β signaling as a candidate intercellular signaling pathway associated with the transition. Together, these data delineate coordinated transcriptional, metabolic, and microenvironmental changes during the proestrus-to-estrus switch. This study provides a high-resolution cellular resource for the porcine ovary across proestrus and estrus and proposes ERBB4 , SLC1A5 , and TGF-β pathway components as candidate molecular features associated with estrus-related ovarian changes. These findings may support improved estrus detection, earlier recognition of reproductive disorders, and more precise reproductive management in swine production systems.