AutoriPetecchia L, Sabatini F, Usai C, Carnevali S, Ognibene M, Vanni C, Eva A, Fabbri LM, Rossi GA, Ricciardolo FL
AbstractBradykinin (BK) induces fibroblast contraction but the structural changes and intracellular mechanisms involved have not been completely explored. We stimulated HFL-1 fibroblasts with BK to assess: 1) fibroblast contractility; 2) the role of alpha-smooth muscle actin (SMA) in contraction by small interfering RNA (siRNA); 3) alpha-SMA protein expression; 4) alpha-SMA and F-actin structure; 5) intracellular calcium concentration; and 6) phosphorylated myosin light-chain (pMLC) and MLC kinase (MLCK) expression. BK triggered concentration- and time-dependent fibroblast gel contraction in conjunction with alpha-SMA over expression, but not in alpha-SMA-siRNA-treated cells. BK also increased alpha-SMA(+) and F-actin(+) cell number and stress fibre polymerisation (detectable at 5-60 min). These BK-induced changes were associated with an increase in intracellular calcium concentration, which peaked within 15 s, and activation of pMLC, which was detectable at 5-60 min. No MLCK content modification was observed. The different manifestations of the BK-induced fibroblast activation were downregulated at different levels (25-100%) by HOE140, a specific BK B2 receptor (B2R) antagonist and by the Ca(2+) chelator, EGTA. Thus, BK-induced fibroblast contraction, associated with differentiation into alpha-SMA(+) myofibroblasts, is mediated through the activation of the B2R and involves the Ca(2+)/calmodulin pMLC-dependent pathway.
RivistaEuropean Respiratory Journal
Impact factor
Pagina inizio655
Pagina fine664
Autori IBFCesare USAI
Linee di Ricerca IBFMD.P01.001.001