OBJECTIVEInteractions of cells with the extracellular matrix (ECM) are essential for cell differentiation. The authors sought to determine the roles of different ECMs in the expressions of germ cell differentiation associated genes after mouse embryonic stem cells (mESCs) differentiated into embryoid bodies (EBs).

METHODSEBs derived from mESCs were maintained in suspension for 3 days and then cultured on the plates coated with various ECMs, including fibronectin (F), laminin (L), matrigel (M), collagen (C) and nonadhensive agarose (A), respectively, for 1, 2, 3 or 4 days, followed by evaluation of the expressions of the genes associated with germ cell differentiation by RT-PCR.

RESULTSThe EBs of the F and L groups exhibited facilitated adherent differentiation. The expressions of the Blimp-1, Stella, Mvh and Stra8 genes were increased gradually in the F and L but not obviously in the M and C groups. The overall gene expressions were low in the A group, but high and then gradually decreased in the blank control group. Endogenous fibronectin, laminin and integrin beta1 were obviously expressed in the L and control groups.

CONCLUSIONLaminin /integrin beta1 signaling may play a role in regulating the differentiation of mESCs into primordial germ cells (PGCs). Exogenous laminin can facilitate the differentiation of mESC-derived EBs into PGCs by acting on the integrin beta1 subunit, while exogenous fibronectin may be involved in the regulation of the differentiation through other integrin subunit. Endogenous laminin and fibronectin secreted by EBs may also facilitate cell differentiation in the absence of exogenous ECMs.