In search of rat stem Leydig cells: Identification, isolation, and lineage-specific development (PDF)
Ge,Renshan; Dong,Qiang; Sottas,Chantal M.; Papadopoulos,Vassilios; Zirkin,Barry R.; Hardy,Matthew P.
Proceedings of the National Academy of Sciences of the United States of America 103(8): 2719-2724
Publication date: 2006
Leydig cells (LCs) are thought to differentiate from spindle-shaped precursor cells that exhibit some aspects of differentiated function, including 3ß-hydroxysteroid dehydrogenase (3ßHSD) activity. The precursor cells ultimately derive from undifferentiated stem LCs (SLCs), which are postulated to be present in testes before the onset of precursor cell differentiation. We searched for cells in the neonatal rat testis with the abilities to: (i) proliferate and expand indefinitely in vitro (self renew); (ii) differentiate (i.e., 3ßHSD and ultimately synthesize testosterone); and (iii) when transplanted into host rat testes, colonize the interstitium and subsequently differentiate in vivo. At one week postpartum, spindle-shaped cells were seen in the testicular interstitium that differed from the precursor cells in that they were 3ßHSD-negative, luteinizing hormone (LH) receptor (LHR)-negative, and platelet-derived growth factor receptor a (PDGFRa)-positive. These cells were purified from the testes of one-week-old rats. The cells contained proteins known to be involved in LC development, including GATA4, c-kit receptor, and leukemia inhibitory factor receptor. The putative SLCs expanded over the course of six months while remaining undifferentiated. When treated in media that contained thyroid hormone, insulin-like growth factor I, and LH, 40 percent of the putative SLCs came to express 3ßHSD and to synthesize testosterone. When transplanted into host rat testes from which LCs had been eliminated, the putative SLCs colonized the interstitium and subsequently expressed 3ßHSD, demonstrating their ability to differentiate in vivo. We conclude that these cells are likely to be the sought-after SLCs.