Department of Genetics and Molecular Biology, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi, 710061, People's Republic of China.
J Mol Neurosci. 2012 Sep;48(1):53-65. doi: 10.1007/s12031-012-9772-y. Epub 2012 Apr 20.
The trigeminal ganglion (TG) can express and release calcitonin gene-related peptide (CGRP), an important neuropeptide that plays a crucial role in migraine attack and cluster headache. Activation of rat TG increases CGRP expression. However, the regulatory mechanism of CGRP expression in TG neurons remains to be explored. This study aims to evaluate the involvement of mitogen-activated protein kinase (MAPK) pathways in CGRP upregulation after rat TG organ culture. Rat TG was cultured alone for 24 h or cultured in combination with MAPK inhibitors, tumor necrosis factor α (TNF-α), or interleukin 1β (IL-1β) for 24 h. CGRP protein was determined using immunohistochemistry. The mRNA levels of CGRP, TNF-α, and IL-1β were analyzed through real-time quantitative polymerase chain reaction. MAPK phosphorylation was detected via western blot. After rat TG organ culture, the expressions of CGRP, TNF-α, and IL-1β were upregulated at 24 h. The phosphorylation of extracellular signal-regulated kinases (ERK1/2), P38, and c-jun N-terminal kinases (JNK) significantly increased at 30 min compared with fresh rat TG. In addition, both CGRP expression and phosphorylation of ERK1/2, P38, and JNK were enhanced obviously after rat TG treatment with TNF-α or IL-1β compared with fresh rat TG. However, they decreased markedly after rat TG pretreatment with PD98059 (ERK1/2 inhibitor), SB203580 (P38 inhibitor), or SP600125 (JNK inhibitor) compared with rat TG co-culture with TNF-α or IL-1β. In conclusion, the elevated CGRP expression after rat TG organ culture can be regulated via MAPK pathways. The findings provide insight into the molecular mechanisms and experimental evidence for therapeutic targets of migraine.
三叉神经节 (TG) 可以表达和释放降钙素基因相关肽 (CGRP)，这是一种在偏头痛发作和丛集性头痛中起关键作用的重要神经肽。激活大鼠 TG 会增加 CGRP 的表达。然而，TG 神经元中 CGRP 表达的调节机制仍有待探索。本研究旨在评估丝裂原活化蛋白激酶 (MAPK) 途径在大鼠 TG 器官培养后 CGRP 上调中的作用。大鼠 TG 单独培养 24 小时或与 MAPK 抑制剂、肿瘤坏死因子-α (TNF-α) 或白细胞介素 1β (IL-1β) 联合培养 24 小时。采用免疫组织化学法检测 CGRP 蛋白。通过实时定量聚合酶链反应分析 CGRP、TNF-α 和 IL-1β 的 mRNA 水平。通过 Western blot 检测 MAPK 磷酸化。大鼠 TG 器官培养 24 小时后，CGRP、TNF-α 和 IL-1β 的表达均上调。与新鲜大鼠 TG 相比，细胞外信号调节激酶 (ERK1/2)、P38 和 c-jun N 末端激酶 (JNK) 的磷酸化在 30 分钟时显著增加。此外，与新鲜大鼠 TG 相比，大鼠 TG 用 TNF-α或 IL-1β处理后，CGRP 表达和 ERK1/2、P38 和 JNK 的磷酸化明显增强，而大鼠 TG 用 PD98059(ERK1/2 抑制剂)、SB203580(P38 抑制剂)或 SP600125(JNK 抑制剂)预处理后则明显降低与 TNF-α或 IL-1β共培养的 TG。综上所述，大鼠 TG 器官培养后 CGRP 表达的升高可通过 MAPK 途径调节。这些发现为偏头痛的治疗靶点提供了分子机制和实验证据。
