• Spatial and single-cell transcriptomics revealed seven neuron subtypes in human SCN • A conserved regulatory axis of LHX1-RORB organizes SCN function across species • Human SCN has undergone marked reorganization of its neuropeptide signaling system • AVP/NMS neurons in human SCN are the potential substrates for morningness chronotype Spatial and single-cell transcriptomics revealed seven neuron subtypes in human SCN A conserved regulatory axis of LHX1-RORB organizes SCN function across species Human SCN has undergone marked reorganization of its neuropeptide signaling system AVP/NMS neurons in human SCN are the potential substrates for morningness chronotype The suprachiasmatic nucleus (SCN) is considered the master pacemaker of the circadian clock in mammals, but our current knowledge of the SCN is mostly based on rodent studies. Here, we report a comprehensive molecular and cellular atlas for the adult human SCN by spatial transcriptomics, single-nucleus RNA sequencing, and deep-learning-based histological analysis. We identified seven human SCN neuron subtypes with specific transcriptomes and spatial distributions. Comparison of humans, mice, and non-human primates revealed the conserved functional segregation within the SCN regulated by LIM homeobox 1 (LHX1) and RAR-related orphan receptor B (RORB). Furthermore, our results suggested that the human SCN has undergone marked reorganization of its neuropeptide signaling network. Finally, integrative analysis of human SCN transcriptomes and genome-wide association studies (GWASs) identified arginine vasopressin ( AVP)/ neuromedin S ( NMS) subtype as the potential neuronal correlate for morningness chronotype. Thus, our spatial and single-cell transcriptomic atlas of the human SCN provided a basis for the understanding of neural and molecular mechanisms of the human circadian clock.
Yang et al. (2026) studied this question.