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.
Depertment of Allergy and Immunology, College of Medicine, Mayo Clinic and Foundation, Rochester, MN 55905, USA.
Thomas A
TA
White
Ailing
A
Xue
Eduardo N
EN
Chini
Michael
M
Thompson
Gary C
GC
Sieck
Mark E
ME
Wylam
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