Prenatal exposure to maternal stress drives sex-specific neurodevelopmental disruptions in the fetal hypothalamus

The hypothalamus plays a central role in integrating physiological stressors to maintain homeostasis, yet how fetal neurodevelopment in the hypothalamus is shaped by intrauterine maternal stress exposure remains understudied. This is especially true in the context of sex-divergent mechanisms underlying neurodevelopmental disorders (NDDs), which are increasingly being linked to perturbation of the intrauterine environment. Herein, we utilize a mouse model of prenatal maternal cold stress exposure to study the impacts on neural stem and progenitor cell (NSPC) developmental programs in the fetal hypothalamus. Pregnant mice were exposed to cold stress from embryonic day 11.5 (E11.5) to E15.5 and fetal hypothalamic NSPCs from both male and female embryos were analyzed. Maternal stress induced sex-specific effects in the fetal hypothalamus, increasing TUJ1+ neuron number in males, while enhancing neuronal dendritic arborization in females. To define underlying molecular changes, we performed single-cell RNA sequencing of hypothalamic NSPCs. Interestingly, we identified distinct baseline transcriptional profiles between male and female NSPCs and found that maternal stress shifts female NSPCs toward a more male-like transcriptional state. In females, maternal stress upregulated pathways related to GABAergic differentiation and neuronal projection morphogenesis, with these alterations maintained across more differentiated neuronal populations. Ligand-receptor analysis further indicated that maternal stress alters cell-cell communication within NSPCs, predominantly in females. Together, these findings demonstrate that prenatal maternal stress drives sex-specific alterations in hypothalamic NSPC developmental programs and suggest that disrupted intercellular signaling may contribute to underlying sex differences in social behaviors previously reported for this model (Rosin et al., 2021). SIGNIFICANCE STATEMENTPrenatal stress is a known risk factor for NDDs, but how it shapes early brain development in a sex-specific manner remains understudied. Here, we examined how maternal stress influences NSPCs in the hypothalamus, a brain region critical for regulating the stress response and homeostasis. Using mice as a model system, we found that maternal stress alters how fetal NSPCs develop into neurons in a sex-specific manner. Molecular analyses suggest that maternal stress shifts female NSPCs to become more male-like and alters cell-cell communication. This work advances our understanding of how prenatal maternal stress drives sex differences in neurodevelopmental programming and may help to begin to explain sex-biased vulnerabilities to NDDs.