G-CSF Regulates the Expression of mRNA for Collagen Type VI and Collagen VI Production in Human Bone Marrow Stromal...

Bone marrow stromal cells produce several extracellular matrix molecules, which are instrumental for progenitor cell attachement, development and survival. Evidence available suggests that collagen type VI produced by marrow stroma, plays a role in progenitor cell attachment and matrix conformation. To investigate whether the steady-state level of collagen VI expression is modulated by growth factors, we analyzed the effect of G-CSF in the expression of collagen type VI mRNA and collagen VI production by human bone marrow stromal cells. Results show that G-CSF, a growth factor extensively used for the mobilization of progenitor cells, decreases the level of expression of collagen type VI mRNA, but not that of mRNA for collagen type I and fibronectin. The downregulation of collagen VI gene expression was paralleled by a decrease in the secretion and accumulation of collagen VI. Since, G-CSF does not influence the growth of stromal cells, the observed effects are not secondary to proliferative stimulation by growth factor. These results suggest that, in addition to the well established action of G-CSF on progenitor and mature cells, it also modulates via stromal cells, the expresion of a particular type of extracellular matrix component.