The aim of our study was to investigate, in primary cultures of normal human lung fibroblasts, the signal transduction pathways activated by endothelin (ET)-1 and its effects on cell proliferation and interleukin-6 (IL-6) production. Cells were exposed for 2 h to ET-1 (100 nM) in the presence or absence of an overnight pretreatment with either ETA or ETB selective receptor antagonists (BQ-123 and BQ-788, respectively). After cell lysis, immunoblotting was performed using monoclonal antibodies against the phosphorylated forms of mitogen-activated protein kinases (MAPK). Cell count was performed using trypan blue staining, and IL-6 release into cell culture supernatants was assessed by ELISA. ET-1 induced a two-fold increase in the phosphorylation pattern of the c-Jun N-terminal kinase (JNK) subgroup of MAPK, enhanced by almost three-folds the total cell number (p<0.01), and also elicited a significant increase in IL-6 production (from 148 to 325 pg/ml; p<0.01). These effects were prevented by a pretreatment with either BQ-123 (300 nM) or the JNK inhibitor SP600125 (20 μM). In conclusion, our findings suggest that in human lung fibroblasts ET-1 may exert a profibrogenic action due to an ETA receptor-dependent, MAPK-mediated induction of cell proliferation and IL-6 synthesis.
Effects of endothelin-1 on MAPK activation, IL-6 production and cell proliferation in normal human lung fibroblasts
VATRELLA, Alessandro;
2004-01-01
Abstract
The aim of our study was to investigate, in primary cultures of normal human lung fibroblasts, the signal transduction pathways activated by endothelin (ET)-1 and its effects on cell proliferation and interleukin-6 (IL-6) production. Cells were exposed for 2 h to ET-1 (100 nM) in the presence or absence of an overnight pretreatment with either ETA or ETB selective receptor antagonists (BQ-123 and BQ-788, respectively). After cell lysis, immunoblotting was performed using monoclonal antibodies against the phosphorylated forms of mitogen-activated protein kinases (MAPK). Cell count was performed using trypan blue staining, and IL-6 release into cell culture supernatants was assessed by ELISA. ET-1 induced a two-fold increase in the phosphorylation pattern of the c-Jun N-terminal kinase (JNK) subgroup of MAPK, enhanced by almost three-folds the total cell number (p<0.01), and also elicited a significant increase in IL-6 production (from 148 to 325 pg/ml; p<0.01). These effects were prevented by a pretreatment with either BQ-123 (300 nM) or the JNK inhibitor SP600125 (20 μM). In conclusion, our findings suggest that in human lung fibroblasts ET-1 may exert a profibrogenic action due to an ETA receptor-dependent, MAPK-mediated induction of cell proliferation and IL-6 synthesis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
