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 underly ing cranial sutures in the regulation of sutural fate. These studies have i mplicated regional differentiation of the dura mater based on association w ith fusing and patent rat cranial sutures. The pur-pose of these experiment s was to isolate and characterize dural cells associated with fusing (poste rior frontal) and patent (sagittal) rat cranial sutures. Six-day-old rats w ere killed, and the dura mater underlying the posterior frontal and sagitta l sutures was harvested. Dural cells were briefly trypsinized and allowed t o 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 hum an meningeal cells), cellular proliferation, density at confluence (a measu re of cellular contact inhibition), and alkaline phosphatase production. Iu , addition, bone nodule formation and collagen I production were analyzed i n 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-derive d 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 p roperties, including alkaline phosphatase production, collagen I expression , and bone nodule formation in vitro. The possible mechanisms by which regi onal differentiation of suture-derived dural cells occur are discussed.