Tumor necrosis factor alpha and interleukin-1beta stimulate the expression of cyclooxygenase II but do not alter prostaglandin E2 receptor mRNA levels in cultured dorsal root ganglia cells.
Tumor necrosis factor alpha and interleukin-1beta stimulate the expression of cyclooxygenase II but do not alter prostaglandin E2 receptor mRNA levels in cultured dorsal root ganglia cells.
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发表时间：
2005
期刊：
影响因子：
7.4
通讯作者：
J. Fehrenbacher;T. Burkey;G. Nicol;M. Vasko
中科院分区：
文献类型：
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作者：
J. Fehrenbacher;T. Burkey;G. Nicol;M. Vasko
肿瘤坏死因子α（TNF α）和白细胞介素1 β（IL-1 β）是能够改变感觉神经元敏感性的促炎细胞因子。由于IL-1 β和TNF α引起的致敏作用可通过抑制诱导酶环氧化酶-II（考克斯-2）而被阻断，因此我们检测了这些细胞因子是否可增加背根神经节（DRG）培养物中考克斯-2的表达。用IL-1 β或TNF α处理细胞培养物可增加免疫反应性考克斯-2，通过免疫印迹法测定，呈时间和浓度依赖性。用10 ng/ml IL-1 β或50 ng/ml TNF α预处理24 h，分别使考克斯-2表达增加50倍和8倍于基础水平。免疫组织化学证实了考克斯-2样免疫反应性在培养的神经元和非神经元细胞中的存在。IL-1受体拮抗剂的加入阻断了IL-1 β对考克斯-2表达的诱导，但没有改变TNF α刺激的考克斯-2的增加，表明TNF α的机制不限于增加IL-1 β的表达。考克斯-2的基础表达和TNF α诱导的表达不依赖于生长培养基中NGF的存在。IL-1 β和TNF α处理2-4 h可使前列腺素E2（PGE 2）的产生增加2-4倍，而考克斯-2抑制剂NS-398预处理可阻断该作用。将培养物暴露于PGE 2、IL-1 β或TNF α 24 h未改变PGE 2受体（EP）mRNA水平。这些结果表明，TNF α和IL-1 β诱导培养的DRG细胞中考克斯-2而非EP受体的功能性表达，并提示，马槟榔碱诱导的感觉神经元敏化继发于前列腺素产生，而非EP受体的改变。
Tumor necrosis factor alpha (TNFalpha) and interleukin 1beta (IL-1beta) are pro-inflammatory cytokines capable of altering the sensitivity of sensory neurons. Because sensitization elicited by IL-1beta and TNFalpha is blocked by inhibition of the inducible enzyme, cyclooxygenase-II (COX-2), we examined whether these cytokines could increase COX-2 expression in dorsal root ganglion (DRG) cultures. Treatment of cell cultures with either IL-1beta or TNFalpha increases immunoreactive COX-2, as measured by immunoblotting, in a time- and concentration-dependent manner. A 24-h pretreatment with 10 ng/ml IL-1beta or 50 ng/ml TNFalpha augmented COX-2 expression 50- and 8-fold over basal levels, respectively. Immunohistochemistry established the presence of COX-2-like immunoreactivity in both neuronal and non-neuronal cells in culture. The addition of IL-1 receptor antagonist blocked the induction of COX-2 expression by IL-1beta, but did not alter TNFalpha-stimulated increases in COX-2, indicating that the mechanism of TNFalpha is not limited to increasing the expression of IL-1beta. The basal and TNFalpha-induced expression of COX-2 was not dependent on the presence of NGF in the growth media. IL-1beta and TNFalpha treatment for 24 h enhanced prostaglandin E2 (PGE2) production 2-4-fold, which was blocked by pretreatment with the COX-2 inhibitor, NS-398. Exposing cultures to PGE2, IL-1beta, or TNFalpha for 24 h did not alter PGE2 receptor (EP) mRNA levels. These results indicate that TNFalpha and IL-1beta induce the functional expression of COX-2 but not EP receptors in DRG cells in culture and suggest that cytokine-induced sensitization of sensory neurons is secondary to prostaglandin production and not alterations in EP receptors.