Integrated single-cell analyses decode the developmental landscape of the human fetal spine

The spine has essential roles in supporting body weight, and safely passaging the neural elements between the body and the brain. In this study, we used integrated single-cell RNA sequencing and single-cell transposase-accessible chromatin sequencing analyses to reveal the cellular heterogeneity, linage, and transcriptional regulatory network of the developing human spine. We found that EPYC+HAPLN1+ fibroblasts with stem cell characteristics could differentiate into chondrocytes by highly expressing the chondrogenic markers ACAN and COL2A1. Neurons could originate from neuroendocrine cells, and MEIS2 may be an essential transcription factor that promotes spinal neural progenitor cells to selectively differentiate into neurons during early gestation. Furthermore, the interaction of NRP2_SEMA3C and CD74_APP between macrophages and neurons may be essential for spinal cord development. Our integrated map provides a blueprint for understanding human spine development in the early- and midgestational stages at single-cell resolution and offers a tool for investigating related diseases.