(Endo)cannabinoids mediate different Ca²⁺ entry mechanisms in human bronchial epithelial cells

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• 作者：Effimia Gkoumassi ; Bart G. J. Dekkers ; Melloney J. Dr枚ge ; Carolina R. S. Elzinga ; Rutger E. Hasenbosch ; Herman Meurs ; S. Adriaan Nelemans ; Martina Schmidt and Johan Zaagsma
• 关键词：(Endo)cannabinoid ; Virodhamine ; Calcium ; Transient receptor potential ; Human bronchial epithelial cells ; Arachidonic acid ; Capacitative calcium entry ; Non ; capacitative calcium entry
• 刊名：Naunyn-Schmiedeberg's Archives of Pharmacology
• 出版时间：July, 2009
• 出版年：2009
• 期刊代码：190_0028-1298
• 类别：bio
• 卷：380
• 期：1
• 页码：67-77
• 数据来源：sp

摘要

In human bronchial epithelial (16HBE14o−) cells, CB₁ and CB₂ cannabinoid receptors are present, and their activation by the endocannabinoid virodhamine and the synthetic non-selective receptor agonist CP55,940 inhibits adenylyl cyclase and cellular interleukin-8 release. Here, we analyzed changes in intracellular calcium ([Ca2+]_i) evoked by Δ9-tetrahydrocannabinol (Δ9-THC), CP55,940, and virodhamine in 16HBE14o− cells. Δ9-THC induced [Ca2+]_i increase and a large transient [Ca2+]_i mobilization, the latter probably reflecting store-depletion-driven capacitative Ca2+ entry (CCE). In contrast, CP55,940 induced a rather moderate Ca2+ influx and a sustained [Ca2+]_i mobilization. CP55,940-induced Ca2+ influx was inhibited by Ni2+, indicating CCE, possibly mediated by transient receptor potential channel TRPC1, the mRNA of which is expressed in 16HBE14o− cells. CP55,940-induced calcium alterations were mimicked by virodhamine concentrations below 30 μM. Interestingly, higher virodhamine induced an additional Ca2+ entry, insensitive to Ni2+, but sensitive to the TRPV1 antagonist capsazepine, the TRPV1-TRPV4 inhibitor ruthenium red, and the non-CCE (NCCE) inhibitors La3+ and Gd3+. Such pharmacological profile is supported by the presence of TRPV1, TRPV4, and TRPC6 mRNAs as well as TRPV1 and TRPC6 proteins in 16HBE14o− cells. Cannabinoid receptor antagonists increased virodhamine-induced Ca2+ entry. Virodhamine also enhanced arachidonic acid release, which was insensitive to cannabinoid receptor antagonism, but sensitive to the phospholipase A₂ inhibitor quinacrine, and to capsazepine. Arachidonic acid induced [Ca2+]_i increase similar to virodhamine. Collectively, these observations suggest that [Ca2+]_i alterations induced by Δ9-THC, CP55,940 and by low concentrations of virodhamine involve mobilization and subsequent CCE mechanisms, whereas such responses by high virodhamine concentrations involve NCCE pathways.