Sertoli cells are the source of stem cell factor for spermatogenesis.

Several cell types have been proposed to create the required microenvironment for spermatogenesis. However, expression patterns of the key growth factors produced by these somatic cells have not been systematically studied and no such factor has been conditionally deleted from its primary source(s), raising the question of which cell type(s) are the physiological sources of these growth factors. Here, using single-cell RNA sequencing and a series of fluorescent reporter mice, we found that stem cell factor (Scf), one of the essential growth factors for spermatogenesis, was broadly expressed in testicular stromal cells, including Sertoli, endothelial, Leydig, smooth muscle and Tcf21-CreER+ stromal cells.

Perivenous Stellate Cells Are the Main Source of Myofibroblasts and Cancer-Associated Fibroblasts Formed After Chronic Liver Injuries.

Background And Aims: Studies of the identity and pathophysiology of fibrogenic HSCs have been hampered by a lack of genetic tools that permit specific and inducible fate-mapping of these cells in vivo. Here, by single-cell RNA sequencing of nonparenchymal cells from mouse liver, we identified transcription factor 21 (Tcf21) as a unique marker that restricted its expression to quiescent HSCs.

Approach And Results: Tracing Tcf21 cells by Tcf21-CreER (Cre-Estrogen Receptor fusion protein under the control of Tcf21 gene promoter) targeted ~10% of all HSCs, most of which were located at periportal and pericentral zones.

Luteinizing hormone signaling restricts hematopoietic stem cell expansion during puberty.

The number and self-renewal capacity of hematopoietic stem cells (HSCs) are tightly regulated at different developmental stages. Many pathways have been implicated in regulating HSC development in cell autonomous manners; however, it remains unclear how HSCs sense and integrate developmental cues. In this study, we identified an extrinsic mechanism by which HSC number and functions are regulated during mouse puberty.