Moreover, Egr 1 compound libraries siRNA also blocked the NE induced PlGF secretion in medium of BEAS 2B and AEC II. Moreover, NE increased the PlGF e pression in endothelial cell but not in fibroblast cell. Taken together, other than natural activity of proteolysis, NE increased the PlGF e pressions and promoted PlGF secretion. PlGF induced apoptosis in LE Cells via JNK and PKC signaling pathways A previous study indicated that 100 ng ml PlGF induced MLE 15 cell apoptosis with an unknown mechanism. It has been previously demonstrated that PlGF increased apoptosis in MLE 15 cells and BEAS 2B via JNK and p38 mitogen activated protein kinase signaling pathways. In order to confirm and e plore the mechanisms underlying PlGF induced LE cells apoptosis, BEAS 2B and AEC II were treated with 100 ng ml recombinant PlGF for 24 h.

Although the results of Western blot analysis revealed that PlGF didnt activate p38 MAPK significantly, PlGF induced a prolonged and enhanced phosphorylation of JNK and PKC in AEC II. PlGF also activated PKC pathways in BEAS 2B. Blockade of JNK or PKC signaling by JNK inhibitor, SP600125, or transfection with PKC siRNA had no effect on PlGF activated PKC or JNK, suggesting no crosstalk between PlGF activated JNK and PKC signaling pathways. Further evaluating the roles of JNK and PKC in PlGF induced apoptosis, BEAS 2B and AEC II were pre treated with JNK inhibitor or transfected with PKC siRNA to block the PlGF down stream signaling pathways, then treated with 0 100 ng ml PlGF for 24 h.

Results of flow cytometry assay and TUNEL assay indicated that first, e ogenous PlGF dose dependently increased BEAS 2B and AEC II apoptotic levels and second, the JNK and PKC signaling pathways played crucial roles Batimastat in PlGF stimulated LE cell apoptosis. The impact of NE induced endogenous PlGF on NE induced LE cell apoptosis was further evaluated in normal human bronchial epithelial cells with serum free medium, which was the applicable condition for NE digestion. This study also further proved that NE caused NHBE apoptosis and blocked endogenous PlGF signaling by VEGFR1 neutralized antibody, which attenuated the NE induced NHBE apoptosis and NE activated JNK and PKC signaling pathways. Intra tracheal instillation of NE increased PlGF e pression and secretion and activated downstream JNK and PKC signaling pathways The role of PlGF in NE induced LE cells apoptosis and emphysema was further confirmed in an animal model.

Wild type and PlGF KO mice were intra tracheally treated with saline or 400 mU ml NE weekly for one month. The pathology of the NE treated mice showed elevated PlGF e selleck chemical pression in alveolar epithelial cell and adjacent endothelial cells than controls. Moreover, NE treated mice displayed more phosphorylated JNK and PKC levels than the control mice. In contrast, ablation of PlGF limited the e pression of PlGF and blocked the NE instillation induced activation of JNK and PKC.