Gene expression of endothelin-1 (ET-1) and release of mature peptide bu activated human neutrophils

Polymorphonuclear neutrophils (PMNs) are only regarded as being involved in the cleavage of exogenous big endothelin-1 (ET-1) to the active peptide. The aims of the present study were to investigate whether PMNs may themselves express mRNA for prepro-ET-1 (pp-ET-1, a long precursor of 212 amino acids) and to determine the capacity of several PMN stimulants to modulate mRNA expression and the release of ET-1 in culture medium. PMNs, isolated from seven healthy adult volunteers, were stimulated with lipopolysaccharide (LPS, 0.25-10 mug/ml), or LPS (1 mug/ml)+phorbol myristate acetate (PMA, 10 ng/ml) or N-formyl-L-methionyl-L- leucyl-L-phenylalanine (f-MLP, 10(-5) M) or tumour necrosis factor-alpha (TNF-alpha, 50 IU/ml). They were found to express pp-ET-1 mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, Enzyme immunoassay (EIA) revealed low levels of ET-1 in the culture supernatants of PMNs stimulated for 3 h with LPS (10 mug/ml) and with LPS + PMA. Control unstimulated PMNs did not express pp-ET-1 mRNA. The local production of ET-1 by PMNs in vivo has significant implications in inflammatory diseases. (C) 2001 Academic Press.