A cell-matrix interaction regulates the undifferentiated state and self-renewal capacity of avian primordial germ cells

Primordial germ cells (PGCs) are lineage restricted precursor cells of sperm and eggs. Whilst avian PGCs from chicken can be cultured and modified to produce genome-edited chickens, the long-term culture of PGCs from other bird species has not been achieved. Here, we explored the effects of a cell-matrix interaction on the in vitro propagation of chicken PGCs. Blocking integrin signaling severely reduced the self-renewal of the PGC, indicating that a PGC-matrix interaction is an essential process for self-renewal. We investigated the properties of somatic cell differentiated PGCs and expression analyses suggested that the PGCs undergo a partial epithelial-to-mesenchymal transition caused by excess PGC-matrix interactions. Finally, we conducted a long-term culture of chicken PGCs with matrix components, resulting in significant induction of their somatic conversion. These results suggested that a high level of PGC-matrix interaction can cause somatic conversion, whilst a moderate level is essential for their proliferation. Overall, we identified a molecular aspect of self-renewal and maintaining undifferentiated states of avian PGCs.