Department of Surgery, Hebei Medical University, Shijiazhuang, Hebei 050017, China.
Chin Med J (Engl). 2012 Jun;125(11):2019-24.
Activation of c-Jun NH(2)-terminal kinase (JNK) has been implicated in neuron apoptosis as well as autophagy in response to various stressors after traumatic brain injury (TBI). However, the underlying molecular pathway remains unclear. Our study assessed whether JNK-mediated p53 phosphorylation might be an important mechanism for enhancing neuron autophagy in response to TBI.
A total of 186 male Sprague-Dawley (SD) rats (300 - 350 g) were used in this study. By randomized block method rats were randomly divided into four groups: sham-operated (n = 46), TBI (n = 60), TBI + dimethyl sulfoxide (DMSO) (n = 40), and TBI + SP600125 (n = 40). JNK was treated with SP600125, a specific JNK inhibitor. JNK, p-P53, Beclin-1, damage-regulated autophagy modulator (DRAM) and p-bcl-2 were evaluated by Western blotting analysis. The cellular localization and expression of Beclin-1 and DRAM was observed by immunofluorescence and immunohistochemistry, and the expression of Beclin-1-Bcl-2/Bcl-xL complexes was evaluated by immunoprecipitation. Multiple-group comparisons were conducted using analysis of variance (ANOVA). P values of less than 0.05 were considered statistically significant.
It was observed that the expression of JNK, p-P53, Beclin-1, DRAM and p-bcl-2 was increasing after TBI, and the expression of Beclin-1 and DRAM was mainly located in the cytoplasm of neurons. But these were significantly inhibited in SP600125 group compared with sham group and TBI + SP600125 group (P < 0.05). The expression of Beclin-1-Bcl-2/Bcl-xL complexes was reduced after TBI.
JNK-mediated p53 phosphorylation might be an important mechanism for enhancing neuron autophagy in response to TBI.
c-Jun NH(2)-末端激酶（JNK）的激活已被牵涉到神经元凋亡以及自噬中，这是对创伤性脑损伤（TBI）后各种应激源的反应。然而，潜在的分子途径尚不清楚。我们的研究评估了 JNK 介导的 p53 磷酸化是否可能是增强神经元自噬对 TBI 反应的重要机制。
本研究共使用了 186 只雄性 Sprague-Dawley（SD）大鼠（300-350g）。通过随机区组法，大鼠被随机分为四组：假手术组（n=46）、TBI 组（n=60）、TBI+二甲基亚砜（DMSO）组（n=40）和 TBI+SP600125 组（n=40）。用 JNK 的特异性抑制剂 SP600125 处理 JNK。通过 Western blot 分析评估 JNK、p-P53、Beclin-1、损伤调节自噬调节剂（DRAM）和 p-bcl-2。通过免疫荧光和免疫组化观察 Beclin-1 和 DRAM 的细胞定位和表达，并通过免疫沉淀评估 Beclin-1-Bcl-2/Bcl-xL 复合物的表达。采用方差分析（ANOVA）进行多组比较。P 值小于 0.05 被认为具有统计学意义。
观察到 TBI 后 JNK、p-P53、Beclin-1、DRAM 和 p-bcl-2 的表达增加，Beclin-1 和 DRAM 的表达主要位于神经元的细胞质中。但与假手术组和 TBI+SP600125 组相比，SP600125 组的表达明显受到抑制（P<0.05）。TBI 后 Beclin-1-Bcl-2/Bcl-xL 复合物的表达减少。
JNK 介导的 p53 磷酸化可能是增强神经元自噬对 TBI 反应的重要机制。
