Induced multilineage differentiation of chicken embryonic germ cells via embryoid body formation.

Although the pluripotent and proliferative capacity of embryonic germ (EG) cells is thought to be equivalent to that of embryonic stem (ES) cells, there has been far less attention focused on the potential use of EG cells for applications in developing novel strategies of tissue transplantation in the treatment of degenerative diseases. In this study, EG cells were derived from primordial germ cells (PGCs) of genital ridges of 4-day-old chicken embryos. These cells satisfied the criteria previously used for defining chicken EG cells by using the expression of markers characteristic to ES cells. When injected subcutaneously, chicken EG cells could form teratomas that enable differentiation into a wide range of tissue types of all three primary cell lineages including neural cells, cartilage, forming bone, adipocytes, blood vessels, smooth muscle, and secretory epithelia in the recipients. Furthermore, cells in embryoid bodies (EBs) expressed lineage-specific markers of three germ layers and could be induced to differentiate into more advanced stages of various committed cell types, including dopamine and cholinergic neurons, astrocytes, oligodendrocytes, adipocytes, and hepatocytes, which were demonstrated by immunocytochemical staining or RT-PCR analysis. These findings support the multilineage differentiation capability of chicken pluripotent EG cells, thus confirming the presumption that chicken embryos may be used as a potential model for better understanding the mechanisms of tissue-specific differentiation and regeneration that will help to devise strategies based on the transplantation of stem cell-derived tissues for restoring function to damaged or diseased tissues.