Role of transient receptor potential C3 in TNF-alpha-enhanced calcium influx in human airway myocytes.
Previous studies have suggested that the proinflammatory cytokine, TNF-alpha, contributes to airway hyperresponsivness by altering airway smooth muscle (ASM) Ca(2+) responses to agonist stimulation. The present study examined the effects of TNF-alpha on Ca(2+) influx pathways in cultured human ASM cells (HASMCs). Proteins encoded by the transient receptor potential (TRP) gene family function as channels through which receptor-operated and store-operated Ca(2+) entry (SOCE) occur. In the present study, the presence of TRPC1, TRPC3, TRPC4, TRPC5, and TRPC6 mRNA and protein expression was confirmed in cultured HASMCs using RT-PCR and Western blot analysis. TNF-alpha treatment significantly increased TRPC3 mRNA and protein levels in HASMCs as well as SOCE. TNF-alpha treatment also increased both the peak and plateau intracellular Ca(2+) concentration responses in HASMCs elicited by acetylcholine and bradykinin. The effects of TNF-alpha treatment on SOCE and agonist-induced intracellular Ca(2+) concentration responses were attenuated using small interfering RNA transfection, which knocked down TRPC3 expression. Thus, in inflammatory airway diseases, TNF-alpha treatment may result in increased myocyte activation due to altered Ca(2+) influx pathways. These results suggest that TRPC3 may be an important therapeutic target in inflammatory airway diseases such as asthma and chronic obstructive pulmonary disease.
White
Thomas A
TA
Depertment of Allergy and Immunology, College of Medicine, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
Xue
Ailing
A
Chini
Eduardo N
EN
Thompson
Michael
M
Sieck
Gary C
GC
Wylam
Mark E
ME
D001980:Bronchi / Q000166:cytology*; D002118:Calcium / Q000819:agonists / Q000378:metabolism*; D002478:Cells, Cultured; D006801:Humans; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000187:drug effects*; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D050052:TRPC Cation Channels / Q000235:genetics / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D012333:RNA, Messenger; D034741:RNA, Small Interfering; D050052:TRPC Cation Channels; D014409:Tumor Necrosis Factor-alpha; D002118:Calcium