Ventrally emigrating neural tube cells differentiate into vascular smooth muscle cells.

A multipotential cell population originating in the ventral part of the hindbrain neural tube, the ventrally emigrating neural tube cells (VENT cells), has recently been shown to migrate into the craniofacial mesenchyme. Because vascular smooth muscle cells develop from this mesenchyme, we sought to determine if the VENT cells contributed to their differentiation. VENT cells were tagged with replication-deficient retroviral vector with LacZ by microinjection into the lumen of the rostral hindbrain of chick embryos on day 2. Embryos were processed for the detection of LacZ positive cells on day 7. LacZ-positive cells were present in the wall of craniofacial arteries and veins. Immunostaining with the smooth muscle alpha-actin confirmed the labeled cells to be smooth muscle cells. It is concluded that some vascular smooth muscle cells differentiate from neural tube cells. the developmental and functional significance of which remains to be established.