A spatiotemporal steroidogenic regulatory network in human fetal adrenal glands and gonads

Abstract

Human fetal adrenal glands produce substantial amounts of dehydroepiandrosterone (DHEA), which is one of the most important precursors of sex hormones. However, the underlying biological mechanism remains largely unknown. Herein, we sequenced human fetal adrenal glands and gonads from 7 to 14 gestational weeks (GW) via 10× Genomics single-cell transcriptome techniques, reconstructed their location information by spatial transcriptomics. Relative to gonads, adrenal glands begin to synthesize steroids early. The coordination among steroidogenic cells and multiple non-steroidogenic cells promotes adrenal cortex construction and steroid synthesis. Notably, during the window of sexual differentiation (8–12 GW), key enzyme gene expression shifts to accelerate DHEA synthesis in males and cortisol synthesis in females. Our research highlights the robustness of the action of fetal adrenal glands on gonads to modify the process of sexual differentiation.

An integrated single-cell analysis of human adrenal cortex development

“…As 3β-hydroxysteroid dehydrogenase type 2/ HSD3B2 is effectively a gatekeeper to glucocorticoid and mineralocorticoid biosynthesis ( Figure 3D ), we investigated HSD3B2 expression across time series data. Although a potential transiently higher expression was seen at 8wpc in bulk RNA-Seq data ( Supplemental Figure 7 ), as reported previously ( 33 , 35 , 39 ), single-cell transcriptomic data showed overall greater increase in HSD3B2 across time, with the highest levels in the DZ cluster at 19wpc ( Figure 3E ). A similar graded increase in CYP21A2 (encoding 21-hydroxylase) and CYP11B1 (encoding 11β-hydroxylase type 1) was seen ( Figure 3E ).…”

“…It is well established that the FZ synthesizes and releases large amounts of DHEA(-S), due to a relative lack of the enzyme 3 β-hydroxysteroid dehydrogenase type 2 (3β-HSD2, encoded by HSD3B2 ) and likely high expression of genes encoding enzymes needed for androgen biosynthesis (i.e., CYP17A1 , POR , CYB5A ). Although a transient wave of HSD3B2 /3β-HSD2 expression has been shown at around 8–9wpc ( 33 , 35 , 39 ), evidence is still emerging as to when the necessary enzymes for glucocorticoid (e.g., cortisol) and mineralocorticoid (e.g., aldosterone) synthesis are expressed during human adrenal development, especially into the second trimester ( 34 , 35 ).…”

“…In recent years, a limited number of studies of human adrenal development or fetal adrenal steroidogenesis have been undertaken using gene expression approaches or focused reverse transcription PCR/IHC of steroid pathways ( 17 , 32 – 36 ). More recently, several studies have started to address human adrenal development or steroidogenesis using single-cell or spatial transcriptomics ( 16 , 37 – 39 ), and induced pluripotent stem cells (iPSCs) have been explored as a model of human fetal adrenal development ( 40 ). However, few data currently exist for detailed transcriptomic analysis of the human adrenal cortex at a single-cell level during the critical first half of gestation (to 20wpc) or transcriptomics linked to developmental anatomy.…”

Application of single-cell RNA sequencing on human testicular samples: a comprehensive review

“…Starting from 7-8 weeks, these somatic progenitors bifurcated into two different developmental paths, one of which is embryonic Sertoli progenitors (marked by SRY , similar to the “early supporting gonadal cells” in Garcia-Alonso et al's work 74 ) and then became fetal SC 79 . The rest path, on the contrary, led to embryonic/fetal interstitial progenitors (marked by ARX and TCF21 , also called Leydig precursor cells by Li et al 73 and called somatic progenitor by Wang et al 84 ), and finally part of the fetal interstitial progenitors became fetal Leydig cells (marked by HSD3B2 and CYP17A1 , also called differentiated LC by Li et al 73 ) 79 , 80 . During the development of prenatal interstitial/Leydig lineage, the enriched molecular pathways altered from “extracellular matrix”/ “cell adhesion” to “steroid biosynthesis”.…”

“…In fact, it was CYP17A1-negative fetal interstitial cells that might finally pass the birth and finally become the common progenitors of adult LC and PTM 79 . Regarding EC, although some studies proved the early appearance of EC in prenatal male gonad 73 , 84 , so far there have been few studies that focused on EC development. Like the previous murine studies 85 , 86 , scRNA-seq data on human the fetal testis also revealed two distinct types of macrophages in the fetal testis, of which one is named SIGLEC15 + fetal testicular macrophages (osteoclast-like) and the other is TREM2 + fetal testicular macrophages (microglia-like) 74 .…”