Programming of the preimplantation embryo by the embryokine colony stimulating factor 2.

Events in the preimplantation period can have long-term consequences that affect embryo competence to establish and maintain pregnancy and which can extend into fetal and postnatal life. One of the molecules responsible for maternal modulation of embryonic development during this time is colony stimulating factor 2, also termed granulocyte-macrophage colony stimulating factor. This cytokine is produced by the oviduct and endometrium and can act on the preimplantation embryo to improve competence of the embryo to establish pregnancy and develop to term. Actions of CSF2 on the embryo include changes in gene expression (particularly for genes related to apoptosis and differentiation), inhibition of apoptosis, and an increase in numbers of cells in the inner cell mass. Female embryos respond to CSF2 differently than male embryos. Alterations in maternal environment during the preimplantation period can affect subsequent development in a sex-specific manner and CSF2 may be one of the maternal signals responsible for this phenomenon.