INCREASE OF TRANSCRIPTION FACTOR EB (TFEB) AND LYSOSOMES IN RAT DRG NEURONS AND THEIR TRANSPORTATION TO THE CENTRAL NERVE TERMINAL IN DORSAL HORN AFTER NERVE INJURY
INCREASE OF TRANSCRIPTION FACTOR EB (TFEB) AND LYSOSOMES IN RAT DRG NEURONS AND THEIR TRANSPORTATION TO THE CENTRAL NERVE TERMINAL IN DORSAL HORN AFTER NERVE INJURY
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DOI：
10.1016/j.neuroscience.2015.11.028
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发表时间：
2016-01-28
期刊：
影响因子：
3.3
通讯作者：
Kiyama, H.
中科院分区：
文献类型：
--
作者：
Jung, J.;Uesugi, N.;Kiyama, H.
在脊髓背角，神经损伤激活小胶质细胞，引起神经病理性疼痛。几项研究阐明了三磷酸腺苷(ATP)参与了小胶质细胞的激活。然而，三磷酸腺苷的来源和释放机制尚不清楚。最近的体外研究表明，溶酶体中的一种三磷酸腺苷标记物奎纳克林通过溶酶体的胞吐作用从背根神经节(DRG)神经元的轴突末端释放到细胞外。在这里，我们证明了一种可能性，即包括由溶酶体-胞吞作用从DRG神经元释放的包括ATP在内的溶酶体成分可能是神经损伤后背根神经节中神经胶质激活的另一个来源。大鼠L5脊神经结扎(SNL)后，控制溶酶体激活和胞吐的转录因子EB(TFEB)的mRNA在DRG中被诱导。同时，L5背根节神经元和同侧背根神经节的溶酶体蛋白、LAMP1和囊泡状核转运体(VNUT)阳性小泡均增加。神经损伤后，脑组织中奎尼卡林染色增强，并与LAMP1免疫反应阳性细胞共存。在DH中，LAMP1阳性小泡也与周围神经标记物Isolectin B4(IB4)凝集素共定位。将编码mCherry-LAMP1的腺病毒注入背根神经节，结果显示mCherry阳性的溶酶体被转运到中枢神经末梢。这些结果提示，DRG中溶酶体合成的激活，包括在DRG中的ATP包装，溶酶体的中枢运输，以及随后的溶酶体从DRG神经元的中枢神经末梢胞吐，可能是背根神经节小胶质细胞激活的部分机制。这种溶酶体介导的小胶质细胞激活机制可能为控制伤害和疼痛提供另一条线索。(C)2015年IBRO。爱思唯尔有限公司出版。保留所有权利。
In the spinal dorsal horn (DH), nerve injury activates microglia and induces neuropathic pain. Several studies clarified an involvement of adenosine triphosphate (ATP) in the microglial activation. However, the origin of ATP together with the release mechanism is unclear. Recent in vitro study revealed that an ATP marker, quinacrine, in lysosomes was released from neurite terminal of dorsal root ganglion (DRG) neurons to extracellular space via lysosomal exocytosis. Here, we demonstrate a possibility that the lysosomal ingredient including ATP released from DRG neurons by lysosomal-exocytosis is an additional source of the glial activation in DH after nerve injury. After rat L5 spinal nerve ligation (SNL), mRNA for transcription factor EB (TFEB), a transcription factor controlling lysosomal activation and exocytosis, was induced in the DRG. Simultaneously both lysosomal protein, LAMP1-and vesicular nuclear transporter (VNUT)-positive vesicles were increased in L5 DRG neurons and ipsilateral DH. The quinacrine staining in DH was increased and co-localized with LAMP1 immunoreactivity after nerve injury. In DH, LAMP1-positive vesicles were also co-localized with a peripheral nerve marker, Isolectin B4 (IB4) lectin. Injection of the adenovirus encoding mCherry-LAMP1 into DRG showed that mCherry-positive lysosomes are transported to the central nerve terminal in DH. These findings suggest that activation of lysosome synthesis including ATP packaging in DRG, the central transportation of the lysosome, and subsequent its exocytosis from the central nerve terminal of DRG neurons in response to nerve injury could be a partial mechanism for activation of microglia in DH. This lysosome-mediated microglia activation mechanism may provide another clue to control nociception and pain. (C) 2015 IBRO. Published by Elsevier Ltd. All rights reserved.