Identification of Rat Testicular Leydig Precursor Cells by Single-Cell-RNA-Sequence Analysis

• DOI: 10.3389/fcell.2022.805249
• Publication Date: 2022-02-15T06:48:13Z
• Authors: Xiaoju Guan; Panpan Chen; Minpeng Ji; Xin Wen; Dan Chen; Xingyi Zhao; Fu Huang; Jiexia Wang; Jingjing Shao; Jiajia Xie; Xingxing Zhao; Fenfen Chen; Jing Tian; Han Lin; Barry R. Zirkin; Ping Duan; Zhijian Su; Haolin Chen
• Keywords: CD90; 0301 basic medicine; Cell and Developmental Biology; 03 medical and health sciences; Leydig cell; ScRNA-seq; QH301-705.5; stem Leydig cell; rat; testis; Biology (General)

Stem Leydig cells (SLCs) play a critical role in the development and maintenance of the adult Leydig cell (ALC) population. SLCs also are present in the adult testis. Their identification, characteristics, and regulation in the adult testis remain uncertain. Using single-cell RNA-seq, we found that the mesenchymal stromal population may be involved in ALC regeneration. Upon ALC elimination, a fraction of stromal cells begins to proliferate while a different fraction begins to differentiate to ALCs. Transcriptomic analysis identified five stromal clusters that can be classified into two major groups representing proliferation and differentiation populations. The proliferating group represents stem cells expressing high levels of CD90, Nes, Lum, Fn and Gap43. The differentiating group represents a progenitor stage that is ready to form ALCs, and specifically expresses Vtn, Rasl11a, Id1 and Egr2. The observation that the actively dividing cells after ALC loss were not those that formed ALCs suggests that stem cell proliferation and differentiation are regulated separately, and that the maintenance of the stromal stem cell pool occurs at the population level. The study also identified specific markers for the major interstitial cell groups and potential paracrine factors involved in the regulation of SLCs. Our data suggest a new theory about SLC identity, proliferation, differentiation, and regulation.