Pulmonary fibroblasts are affected by notch ligands in vitro

The Notch signaling pathway is an essential pathway concerning cell communication. It plays an important role in adult tissue homeostasis and development – in particular cell fate, death and proliferation. As known so far, this signaling pathway is often implicated in the development of many diseases, like e.g. cancer or pulmonary fibrosis. The aim of this study was to illustrate the role of the Notch signaling pathway in the proliferation of human pulmonary fibroblasts with regard to the idiopathic pulmonary fibrosis.

Human pulmonary fibroblasts were seeded onto a 96-well plate and synchronised via cell-starving for 48 hours. After cell-starving, cells were stimulated by two of the five transmembrane ligands of the Notch pathway: Jagged 1 and Delta-like 4 for 24 hours. Cells were stimulated with different concentrations of the ligands [5 µg/ml, 1 µg/ml, 100 ng/ml, 10 ng/ml, 1 ng/ml, 0,1 ng/ml]. As a positive control Fibroblast Growth Factor [100 ng/ml] was used. The proliferation was measured via MTT-Assay at 570nm.

The Notch ligands Jagged-1 and DLL-4 significantly stimulate proliferation of human pulmonary fibroblasts. The effect is comparable with the maximal stimulation of proliferation elicited by the well-known growth factor FGF [100 ng/ml]. ADAM-17 and γ-secretase abolished this effect showing involvement of the Notch receptors.

Consequently the proliferation of the human pulmonary fibroblasts can be stimulated by the Notch ligands Jagged-1 and Delta-like-4 which may be important for the treatment of the idiopathic pulmonary fibrosis.