Tumor necrosis factor-alpha (TNF-α) enhances functional thermal and chemical responses of TRP cation channels in human synoviocytes
Tumor necrosis factor-alpha (TNF-α) enhances functional thermal and chemical responses of TRP cation channels in human synoviocytes
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DOI：
10.1186/1744-8069-5-49
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发表时间：
2009-08-20
期刊：
影响因子：
3.3
通讯作者：
Westlund, Karin N.
中科院分区：
文献类型：
--
作者：
Kochukov, Mikhail Y.;McNearney, Terry A.;Westlund, Karin N.
背景：我们已经发现了几个TRP通道在人类滑膜细胞上的功能性表达，这在关节炎症中已知的钙依赖性增殖和分泌反应中具有重要意义。本研究进一步表征了促炎介质肿瘤坏死因子α （tnf - α, EC50 1.3221 × 10(-10)g/L）预处理后滑膜细胞TRP的表达和对热刺激和渗透刺激的激活反应。结果：携带Fura-2的人SW982滑膜细胞的荧光成像显示：(1)TRPV1激动剂辣椒素和树脂干扰素（20-40%的细胞），(2)中度和有害的温度变化，以及(3)渗透应激TRPV4激活（11.5%的细胞）引起的即时和延迟的胞质钙振荡。tnf - α预处理（1 ng/ml， 8-16小时）显著增加（加倍）辣椒素反应细胞数量和[Ca2+]i尖峰频率，并增强温度诱导的[Ca2+](i)反应的平均振幅。tnf - α预处理8,12和16小时，36或45度浴液激活诱导双峰[Ca2+](i)增加（温控室）。初始温度诱导的快速瞬态峰值和随后的缓慢上升分别反映了TRPV1和TRPV4通道的激活。只有在长时间的tnf - α暴露（12和16小时）后，才能观察到滑膜细胞的招募，并对低渗的TRPV4反应增敏（增加3-4倍）。tnf - α增加TRPV1（8小时峰值）和TRPV4（12小时峰值）免疫染色、mRNA和蛋白表达，TRPV1向膜组分转移。结论：tnf - α对滑膜细胞TRPV1和TRPV4表达和[Ca2+](i)反应的差异增强依赖于TRP刺激和暴露后的时间。随着炎症状况的持续，TRPV1和TRPV4相关性的增强将为炎症疼痛状态下滑膜细胞的病理生理反应提供钙介导的细胞信号。
Background: We have shown functional expression of several TRP channels on human synovial cells, proposing significance in known calcium dependent proliferative and secretory responses in joint inflammation. The present study further characterizes synoviocyte TRP expression and activation responses to thermal and osmotic stimuli after pre-treatment with proinflammatory mediator tumor necrosis factor alpha (TNF-alpha, EC50 1.3221 x 10(-10)g/L).Results: Fluorescent imaging of Fura-2 loaded human SW982 synoviocytes reveals immediate and delayed cytosolic calcium oscillations elicited by ( 1) TRPV1 agonists capsaicin and resiniferatoxin (20-40% of cells), ( 2) moderate and noxious temperature change, and ( 3) osmotic stress TRPV4 activation (11.5% of cells). TNF-alpha pre-treatment ( 1 ng/ml, 8-16 hr) significantly increases (doubles) capsaicin responsive cell numbers and [Ca2+]i spike frequency, as well as enhances average amplitude of temperature induced [Ca2+](i) responses. With TNF-alpha pre-treatment for 8, 12, and 16 hr, activation with 36 or 45 degree bath solution induces bimodal [Ca2+](i) increase (temperature controlled chamber). Initial temperature induced rapid transient spikes and subsequent slower rise reflect TRPV1 and TRPV4 channel activation, respectively. Only after prolonged TNF-alpha exposure ( 12 and 16 hr) is recruitment of synoviocytes observed with sensitized TRPV4 responses to hypoosmolarity (3-4 fold increase). TNF-alpha increases TRPV1 (8 hr peak) and TRPV4 (12 hr peak) immunostaining, mRNA and protein expression, with a TRPV1 shift to membrane fractions.Conclusion: TNF-alpha provides differentially enhanced synoviocyte TRPV1 and TRPV4 expression and [Ca2+](i) response dependent on the TRP stimulus and time after exposure. Augmented relevance of TRPV1 and TRPV4 as inflammatory conditions persist would provide calcium mediated cell signaling required for pathophysiological responses of synoviocytes in inflammatory pain states.