TY - JOUR
T1 - Mechanisms of bradykinin-induced contraction in human fetal lung fibroblasts
AU - Petecchia, L.
AU - Sabatini, F.
AU - Usai, C.
AU - Carnevali, S.
AU - Ognibene, M.
AU - Vanni, C.
AU - Eva, A.
AU - Fabbri, L. M.
AU - Rossi, G. A.
AU - Ricciardolo, F. L M
PY - 2010/9
Y1 - 2010/9
N2 - Bradykinin (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 α-smooth muscle actin (SMA) in contraction by small interfering RNA (siRNA); 3) α-SMA protein expression; 4) α-SMA and F-actin structure; 5) intracellular calcium concentration ([Ca 2+]i); and 6) phosphorylated myosin light-chain (pMLC) and MLC kinase (MLCK) expression. BK triggered concentration- and time-dependent fibroblast gel contraction in conjunction with α-SMA over expression, but not in α-SMA-siRNA-treated cells. BK also increased α-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 [Ca2+]i, 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 Ca2+ chelator, EGTA. Thus, BK-induced fibroblast contraction, associated with differentiation into α-SMA+ myofibroblasts, is mediated through the activation of the B2R and involves the Ca2+/calmodulin pMLC-dependent pathway. Copyright
AB - Bradykinin (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 α-smooth muscle actin (SMA) in contraction by small interfering RNA (siRNA); 3) α-SMA protein expression; 4) α-SMA and F-actin structure; 5) intracellular calcium concentration ([Ca 2+]i); and 6) phosphorylated myosin light-chain (pMLC) and MLC kinase (MLCK) expression. BK triggered concentration- and time-dependent fibroblast gel contraction in conjunction with α-SMA over expression, but not in α-SMA-siRNA-treated cells. BK also increased α-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 [Ca2+]i, 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 Ca2+ chelator, EGTA. Thus, BK-induced fibroblast contraction, associated with differentiation into α-SMA+ myofibroblasts, is mediated through the activation of the B2R and involves the Ca2+/calmodulin pMLC-dependent pathway. Copyright
KW - α-smooth muscle actin
KW - Calcium
KW - Contraction
KW - Fibroblasts
KW - Myosin phosphorylation
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U2 - 10.1183/09031936.00112209
DO - 10.1183/09031936.00112209
M3 - Article
C2 - 20351037
AN - SCOPUS:77956597088
VL - 36
SP - 655
EP - 664
JO - European Journal of Respiratory Diseases
JF - European Journal of Respiratory Diseases
SN - 0903-1936
IS - 3
ER -