TY - JOUR
T1 - TRPC3 regulates release of brain-derived neurotrophic factor from human airway smooth muscle
AU - Vohra, Pawan K.
AU - Thompson, Michael A.
AU - Sathish, Venkatachalem
AU - Kiel, Alexander
AU - Jerde, Calvin
AU - Pabelick, Christina M.
AU - Singh, Brij B.
AU - Prakash, Y. S.
N1 - Funding Information:
Supported by NIH R01 grant HL088029 and HL056470 (Prakash), HL090595 (Pabelick), and DE017102 , 5P20RR017699 , and AI097532 (Singh).
PY - 2013/12
Y1 - 2013/12
N2 - Exogenous brain-derived neurotrophic factor (BDNF) enhances Ca2+ signaling and cell proliferation in human airway smooth muscle (ASM), especially with inflammation. Human ASM also expresses BDNF, raising the potential for autocrine/paracrine effects. The mechanisms by which ASM BDNF secretion occurs are not known. Transient receptor potential channels (TRPCs) regulate a variety of intracellular processes including store-operated Ca2+ entry (SOCE; including in ASM) and secretion of factors such as cytokines. In human ASM, we tested the hypothesis that TRPC3 regulates BDNF secretion. At baseline, intracellular BDNF was present, and BDNF secretion was detectable by enzyme linked immunosorbent assay (ELISA) of cell supernatants or by real-time fluorescence imaging of cells transfected with GFP-BDNF vector. Exposure to the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFα) (20ng/ml, 48h) or a mixture of allergens (ovalbumin, house dust mite, Alternaria, and Aspergillus extracts) significantly enhanced BDNF secretion and increased TRPC3 expression. TRPC3 knockdown (siRNA or inhibitor Pyr3; 10μM) blunted BDNF secretion, and prevented inflammation effects. Chelation of extracellular Ca2+ (EGTA; 1mM) or intracellular Ca2+ (BAPTA; 5μM) significantly reduced secreted BDNF, as did the knockdown of SOCE proteins STIM1 and Orai1 or plasma membrane caveolin-1. Functionally, secreted BDNF had autocrine effects suggested by phosphorylation of high-affinity tropomyosin-related kinase TrkB receptor, prevented by chelating extracellular BDNF with chimeric TrkB-Fc. These data emphasize the role of TRPC3 and Ca2+ influx in the regulation of BDNF secretion by human ASM and the enhancing effects of inflammation. Given the BDNF effects on Ca2+ and cell proliferation, BDNF secretion may contribute to altered airway structure and function in diseases such as asthma.
AB - Exogenous brain-derived neurotrophic factor (BDNF) enhances Ca2+ signaling and cell proliferation in human airway smooth muscle (ASM), especially with inflammation. Human ASM also expresses BDNF, raising the potential for autocrine/paracrine effects. The mechanisms by which ASM BDNF secretion occurs are not known. Transient receptor potential channels (TRPCs) regulate a variety of intracellular processes including store-operated Ca2+ entry (SOCE; including in ASM) and secretion of factors such as cytokines. In human ASM, we tested the hypothesis that TRPC3 regulates BDNF secretion. At baseline, intracellular BDNF was present, and BDNF secretion was detectable by enzyme linked immunosorbent assay (ELISA) of cell supernatants or by real-time fluorescence imaging of cells transfected with GFP-BDNF vector. Exposure to the pro-inflammatory cytokine tumor necrosis factor-alpha (TNFα) (20ng/ml, 48h) or a mixture of allergens (ovalbumin, house dust mite, Alternaria, and Aspergillus extracts) significantly enhanced BDNF secretion and increased TRPC3 expression. TRPC3 knockdown (siRNA or inhibitor Pyr3; 10μM) blunted BDNF secretion, and prevented inflammation effects. Chelation of extracellular Ca2+ (EGTA; 1mM) or intracellular Ca2+ (BAPTA; 5μM) significantly reduced secreted BDNF, as did the knockdown of SOCE proteins STIM1 and Orai1 or plasma membrane caveolin-1. Functionally, secreted BDNF had autocrine effects suggested by phosphorylation of high-affinity tropomyosin-related kinase TrkB receptor, prevented by chelating extracellular BDNF with chimeric TrkB-Fc. These data emphasize the role of TRPC3 and Ca2+ influx in the regulation of BDNF secretion by human ASM and the enhancing effects of inflammation. Given the BDNF effects on Ca2+ and cell proliferation, BDNF secretion may contribute to altered airway structure and function in diseases such as asthma.
KW - Asthma
KW - Inflammation
KW - Lung
KW - Neurotrophin
KW - Signaling
KW - Tropomyosin-related kinase
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U2 - 10.1016/j.bbamcr.2013.07.019
DO - 10.1016/j.bbamcr.2013.07.019
M3 - Article
C2 - 23899746
AN - SCOPUS:84882930916
SN - 0167-4889
VL - 1833
SP - 2953
EP - 2960
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
IS - 12
ER -