TY - JOUR
T1 - A novel Ca2+ influx pathway activated by mechanical stretch in human airway smooth muscle cells
AU - Ito, Satoru
AU - Kume, Hiroaki
AU - Naruse, Keiji
AU - Kondo, Masashi
AU - Takeda, Naoya
AU - Iwata, Susumu
AU - Hasegawa, Yoshinori
AU - Sokabe, Masahiro
PY - 2008/4/1
Y1 - 2008/4/1
N2 - In response to mechanical stretch, airway smooth muscle exhibits various cellular functions such as contraction, proliferation, and cytoskeletal remodeling, all of which are implicated in the pathophysiology of asthma. We tested the hypothesis that mechanical stretch of airway smooth muscle cells increases intracellular Ca2+ concentration ([Ca2+] i) by activating stretch-activated (SA) nonselective cation channels. A single uniaxial stretch (3 s) was given to human bronchial smooth muscle cells cultured on an elastic silicone membrane. After the mechanical stretch, a transient increase in [Ca2+]i was observed. The [Ca 2+]i increase was significantly dependent on stretch amplitude. The augmented [Ca2+]i due to stretch was completely abolished by removal of extracellular Ca2+ and was markedly attenuated by an application of Gd3+, an inhibitor of SA channels, or ruthenium red, a transient receptor potential vanilloid (TRPV) inhibitor. In contrast, the stretch-induced rises of [Ca2+] i were not altered by other Ca2+ channel inhibitors such as nifedipine, BTP-2, and SKF-96365. Moreover, the [Ca2+]i increases were not affected by indomethacin, a cyclooxygenase inhibitor, U-73122, a phospholipase C inhibitor, or xestospongin C, an inhibitor of the inositol-trisphosphate receptor. These findings demonstrate that a novel Ca 2+ influx pathway activated by mechanical stretch, possibly through the Ca2+-permeable SA channel activated directly by stretch rather than by indirect mechanisms via intracellular messenger production, is involved in human airway smooth muscle cells. A molecular candidate for the putative SA channel may be one of the members of the TRPV channel family. Thus, abnormal Ca2+ homeostasis in response to excessive mechanical strain would contribute to the pathogenesis of asthma.
AB - In response to mechanical stretch, airway smooth muscle exhibits various cellular functions such as contraction, proliferation, and cytoskeletal remodeling, all of which are implicated in the pathophysiology of asthma. We tested the hypothesis that mechanical stretch of airway smooth muscle cells increases intracellular Ca2+ concentration ([Ca2+] i) by activating stretch-activated (SA) nonselective cation channels. A single uniaxial stretch (3 s) was given to human bronchial smooth muscle cells cultured on an elastic silicone membrane. After the mechanical stretch, a transient increase in [Ca2+]i was observed. The [Ca 2+]i increase was significantly dependent on stretch amplitude. The augmented [Ca2+]i due to stretch was completely abolished by removal of extracellular Ca2+ and was markedly attenuated by an application of Gd3+, an inhibitor of SA channels, or ruthenium red, a transient receptor potential vanilloid (TRPV) inhibitor. In contrast, the stretch-induced rises of [Ca2+] i were not altered by other Ca2+ channel inhibitors such as nifedipine, BTP-2, and SKF-96365. Moreover, the [Ca2+]i increases were not affected by indomethacin, a cyclooxygenase inhibitor, U-73122, a phospholipase C inhibitor, or xestospongin C, an inhibitor of the inositol-trisphosphate receptor. These findings demonstrate that a novel Ca 2+ influx pathway activated by mechanical stretch, possibly through the Ca2+-permeable SA channel activated directly by stretch rather than by indirect mechanisms via intracellular messenger production, is involved in human airway smooth muscle cells. A molecular candidate for the putative SA channel may be one of the members of the TRPV channel family. Thus, abnormal Ca2+ homeostasis in response to excessive mechanical strain would contribute to the pathogenesis of asthma.
KW - Ca channels
KW - Mechanical stress
KW - Mechanotransduction
KW - Transient receptor potential
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U2 - 10.1165/rcmb.2007-0259OC
DO - 10.1165/rcmb.2007-0259OC
M3 - Article
C2 - 17975175
AN - SCOPUS:41449112978
SN - 1044-1549
VL - 38
SP - 407
EP - 413
JO - American Journal of Respiratory Cell and Molecular Biology
JF - American Journal of Respiratory Cell and Molecular Biology
IS - 4
ER -