JAK-STAT signaling regulation of chicken embryonic stem cell differentiation into male germ cells

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling is crucial in chicken germ stem cell differentiation, but its role in the regulation of germ cell differentiation is unknown. To address this, cucurbitacin I or interleukin 6 was used to inhibit or activate JAK-STAT signaling during embryonic stem cells (ESCs) differentiation. The expression of downstream JAK-STAT signaling molecules was assessed by Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR). PAS, and immunohistochemical staining of frozen sections was used to determine the appearance of primordial germ cells (PGCs) and, later, spermatogonial stem cells (SSCs) during gonadal development. Inhibition of the JAK-STAT signaling resulted in decreased expression of JAK2 and STAT3 as well as of PGCs markers; moreover, the proportion of CVH and C-KIT positive cells as well as the yield of PGCs were remarkably decreased, and the gonad was smaller than that of control samples. Conversely, activation of JAK-STAT resulted in increased expression of JAK2 and STAT3 as well as that of PGC marker CVH. In addition, the proportion of CVH and C-KIT-positive cells as well as the PGC yield was increased, and the gonad was significantly larger than that from control samples. Collectively, our results suggested that JAK-STAT effectively promoted the formation of PGCs in the genital ridge during early embryogenesis in vivo and played a positive role in the regulation of ESC to SSC differentiation in vitro, with JAK2 and STAT3 functioning as pivotal factors for intracellular signal transduction.