TY - JOUR
T1 - Caveolin-1 in cytokine-induced enhancement of intracellular Ca 2+ in human airway smooth muscle
AU - Sathish, Venkatachalem
AU - Abcejo, Amard J.
AU - Vanoosten, Sarah Kay
AU - Thompson, Michael A.
AU - Prakash, Y. S.
AU - Pabelick, Christina M.
PY - 2011/10
Y1 - 2011/10
N2 - Diseases such as asthma are characterized by airway hyperresponsiveness. Enhanced airway smooth muscle (ASM) intracellular Ca 2+ ([Ca 2+] i) response to agonist stimulation leading to increased airway constriction has been suggested to contribute to airway hyperresponsiveness. Caveolae are flask-shaped plasma membrane invaginations that express the scaffolding protein caveolin and contain multiple proteins important in [Ca 2+] i signaling (e.g., agonist receptors, ion channels). We recently demonstrated that caveolae and caveolin-1 are important in [Ca 2+] i regulation in human ASM. Proinflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-13 modulate [Ca 2+] i in ASM. We hypothesized that cytokine upregulation of caveolar signaling in ASM contributes to enhanced agonist-induced [Ca 2+] i in inflammation. Enzymatically dissociated human ASM cells were exposed to medium (control), 20 ng/ml TNF-α, or 50 ng/ml IL-13 for 24 h. Caveolae-enriched membrane fractions displayed substantial increase in caveolin-1 and -2 expressions by TNF-α and IL-13. Transfection with caveolin-1-mRed DNA substantially accelerated and increased plasma membrane caveolin-1 expression by TNF-α and to a lesser extent by IL-13. Caveolin-1 enhancement was inhibited by nuclear factor-κB and mitogen-activated protein kinase inhibitors. In fura 2-loaded ASM cells, [Ca 2+] i responses to 1μ M ACh, 10 μM histamine, or 10 nM bradykinin were all exaggerated by TNF-α as well as IL-13 exposure. However, disruption of caveolae using caveolin- 1 suppression via small-interfering RNA resulted in significant blunting of agonist-induced [Ca 2+] i responses of vehicle and TNF-α- exposed cells. These functional data were correlated to the presence of TNFR 1 receptor (but not the IL-4/IL-13 receptor) within caveolae. Overall, these results indicate that caveolin-1 plays an important role in airway inflammation by modulating the effect of specific cytokines on [Ca 2+] i.
AB - Diseases such as asthma are characterized by airway hyperresponsiveness. Enhanced airway smooth muscle (ASM) intracellular Ca 2+ ([Ca 2+] i) response to agonist stimulation leading to increased airway constriction has been suggested to contribute to airway hyperresponsiveness. Caveolae are flask-shaped plasma membrane invaginations that express the scaffolding protein caveolin and contain multiple proteins important in [Ca 2+] i signaling (e.g., agonist receptors, ion channels). We recently demonstrated that caveolae and caveolin-1 are important in [Ca 2+] i regulation in human ASM. Proinflammatory cytokines such as tumor necrosis factor (TNF)-α and interleukin (IL)-13 modulate [Ca 2+] i in ASM. We hypothesized that cytokine upregulation of caveolar signaling in ASM contributes to enhanced agonist-induced [Ca 2+] i in inflammation. Enzymatically dissociated human ASM cells were exposed to medium (control), 20 ng/ml TNF-α, or 50 ng/ml IL-13 for 24 h. Caveolae-enriched membrane fractions displayed substantial increase in caveolin-1 and -2 expressions by TNF-α and IL-13. Transfection with caveolin-1-mRed DNA substantially accelerated and increased plasma membrane caveolin-1 expression by TNF-α and to a lesser extent by IL-13. Caveolin-1 enhancement was inhibited by nuclear factor-κB and mitogen-activated protein kinase inhibitors. In fura 2-loaded ASM cells, [Ca 2+] i responses to 1μ M ACh, 10 μM histamine, or 10 nM bradykinin were all exaggerated by TNF-α as well as IL-13 exposure. However, disruption of caveolae using caveolin- 1 suppression via small-interfering RNA resulted in significant blunting of agonist-induced [Ca 2+] i responses of vehicle and TNF-α- exposed cells. These functional data were correlated to the presence of TNFR 1 receptor (but not the IL-4/IL-13 receptor) within caveolae. Overall, these results indicate that caveolin-1 plays an important role in airway inflammation by modulating the effect of specific cytokines on [Ca 2+] i.
KW - Asthma
KW - Caveolae
KW - Cytokine
KW - Inflammation
KW - Lipid raft
KW - Lung
KW - Mitogenactivated protein kinase
KW - Nuclear factor-κB
KW - Small-interfering ribonucleic acid
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UR - http://www.scopus.com/inward/citedby.url?scp=80053344464&partnerID=8YFLogxK
U2 - 10.1152/ajplung.00019.2011
DO - 10.1152/ajplung.00019.2011
M3 - Article
C2 - 21803870
AN - SCOPUS:80053344464
SN - 1040-0605
VL - 301
SP - L607-L614
JO - American Journal of Physiology - Lung Cellular and Molecular Physiology
JF - American Journal of Physiology - Lung Cellular and Molecular Physiology
IS - 4
ER -