Regional differentiation of rat cranial suture-derived dural cells is dependent on association with fusing and patent cranial sutures.

A significant body of literature supports a role for the dura mater underlying cranial sutures in the regulation of sutural fate. These studies have implicated regional differentiation of the dura mater based on association with fusing and patent rat cranial sutures. The purpose of these experiments was to isolate and characterize dural cells associated with fusing (posterior frontal) and patent (sagittal) rat cranial sutures. Six-day-old rats were killed, and the dura mater underlying the posterior frontal and sagittal sutures was harvested. Dural cells were briefly trypsinized and allowed to reach confluence. Two litters (10 animals per litter) were used for each set of experiments. Cells were harvested after the first and fifth passages for analysis of vimentin and desmoplakin expression (characteristic of human meningeal cells), cellular proliferation, density at confluence (a measure of cellular contact inhibition), and alkaline phosphatase production. In addition, bone nodule formation and collagen I production were analyzed in first passage cells. The results indicate that suture-derived dural cells can be established and that these cells coexpress vimentin and desmoplakin. In addition, it is demonstrated that first-passage sagittal suture-derived dural cells proliferate significantly faster and have decreased cellular contact inhibition than posterior frontal suture-derived cells (p < 0.01). Finally, it is shown that suture-derived dural cells have osteoblast-like properties, including alkaline phosphatase production, collagen I expression, and bone nodule formation in vitro. The possible mechanisms by which regional differentiation of suture-derived dural cells occur are discussed.