A spatiotemporal regulatory network for steroidogenesis of human fetal adrenal glands and gonads

Human fetal adrenal glands are huge endocrine organ, produce prodigious quantities of dehydroepiandrosterone and its sulfate (DHEA/DHEAS), which is the most prominent precursor for steroid hormones, adrenal gonads dysfunction leads to states of virilization or effemination. However, for a long time the function of fetal adrenal in initial sex differentiation is unclear. Herein, we draw out a single-cell transcriptional landscape of human fetal adrenals and gonad from 6 to 14 gestational weeks (GW). We found that the adrenal glands begin to express CYP17A1 steroid-related enzyme much early than testis, subsequent testis steroid express pattern support de novo or halfway testosterone synthesis. Excepted steroidogenic cell, notably, the immune cells or neurocyte shows steroid metabolism or regulation ability, such as CD5L+ macrophage interacted with steroidogenic cell and SRD5A1+ AKR1C2+ chromaffin cells synthesis active testosterone DHT through backdoor pathway. Sex different were found at adrenal glands and gonad development: there is a small HSD3B2 peak occurs only in female adrenal glands around 10-12 GW within the time window of sex differentiation. SST expression levels or SST+ cells quantity in adrenal glands and gonads are different in two gender. Our research indicates that a sex different in spatial and temporal disparities steroidogenic regulatory networks in adrenal glands and gonads, facilitating further exploration of development and physiology of human adrenal glands. Overall design: Adrenal and gonad samples from 6-14 GW human fetuses were used for single cell RNA sequencing by 10X Genomics