Department of Pharmacology & Physiology, Drexel University College of Medicine, Philadelphia, PA, USA.
Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
J Proteomics. 2020 Jan 16;211:103540. doi: 10.1016/j.jprot.2019.103540. Epub 2019 Oct 24.
Exosomes are 30-150 nm extracellular vesicles mediating intercellular communication. Disease states can alter exosome composition affecting the message carried and thereby, its functional impact. The objective of this study was to identify proteins present in these vesicles in a mouse model of neuropathic pain induced by spared nerve injury (SNI). Small extracellular vesicles (sEVs) were purified from serum four weeks after SNI surgery and the protein composition was determined using tandem mass spectrometry and cytokine array. Proteomic analysis detected 274 gene products within sEVs. Of these, 24 were unique to SNI model, 100 to sham surgery control and five to naïve control samples. In addition to commonly expressed sEVs proteins, multiple members of serpin and complement family were detected in sEVs. Cytokine profiling using a membrane-based antibody array showed significant upregulation of complement component 5a (C5a) and Intercellular Adhesion Molecule 1 (ICAM-1) in sEVs from SNI model compared to sham control. We observed a differential distribution of C5a and ICAM-1 within sEVs and serum between sham and SNI, indicating changes from local or paracrine to long distance signaling under neuropathic pain. Our studies suggest critical roles for cargo sorting of vesicular proteins in mediating signaling mechanisms underlying neuropathic pain. SIGNIFICANCE: Approximately 100 million U.S. adults are burdened by chronic pain. Neuropathic pain resulting from injury or dysfunction of the nervous system is challenging to treat. Unlike acute pain that resolves over time, chronic pain persists resulting in changes in the peripheral and central nervous system. The transport of biomolecular cargo comprised of proteins and RNAs by small extracellular vesicles (sEVs) including exosomes has been proposed to be a fundamental mode of intercellular communication. To obtain insights on the role of exosome-mediated information transfer in the context of neuropathic pain, we investigated alterations in protein composition of sEVs in a mouse model of neuropathic pain induced by spared nerve injury (SNI). Our studies using mass spectrometry and cytokine array show that sEVs from SNI model harbor unique proteins. We observed an upregulation of C5a and ICAM-1 in exosomes from SNI model compared to control. There was a differential distribution of C5a and ICAM-1 within exosomes and serum, between control and SNI suggesting a switch from local to long distance signaling. Our studies suggest critical roles for cargo sorting of vesicular proteins in mediating signaling under neuropathic pain.
外泌体是 30-150nm 的细胞外囊泡，介导细胞间通讯。疾病状态可以改变外泌体的组成，影响携带的信息，从而影响其功能。本研究的目的是在 spared nerve injury (SNI) 诱导的神经性疼痛的小鼠模型中鉴定存在于这些囊泡中的蛋白质。在 SNI 手术后 4 周，从小鼠血清中纯化小细胞外囊泡 (sEVs)，并使用串联质谱和细胞因子阵列测定其蛋白组成。蛋白质组学分析在 sEVs 中检测到 274 个基因产物。其中，24 个是 SNI 模型特有的，100 个是假手术对照的，5 个是正常对照的。除了常见的 sEVs 蛋白外，还在 sEVs 中检测到多个丝氨酸蛋白酶和补体家族成员。使用基于膜的抗体阵列进行细胞因子分析显示，与假手术对照相比，SNI 模型的 sEVs 中补体成分 5a (C5a) 和细胞间黏附分子 1 (ICAM-1) 显著上调。我们观察到 sEVs 和血清中 C5a 和 ICAM-1 在假手术和 SNI 之间的分布存在差异，表明在神经性疼痛下，信号从局部或旁分泌转变为远距离信号。我们的研究表明，囊泡蛋白的货物分拣在介导神经性疼痛的信号机制中起着关键作用。
大约有 1000 万美国成年人受到慢性疼痛的困扰。由于神经系统损伤或功能障碍引起的神经性疼痛难以治疗。与随着时间的推移而消退的急性疼痛不同，慢性疼痛持续存在，导致外周和中枢神经系统发生变化。由蛋白质和 RNA 组成的生物分子货物通过小细胞外囊泡 (sEVs) 包括外泌体的运输被认为是细胞间通讯的一种基本模式。为了深入了解外泌体介导的信息传递在神经性疼痛背景下的作用，我们研究了在 spared nerve injury (SNI) 诱导的神经性疼痛的小鼠模型中外泌体蛋白质组成的变化。我们使用质谱和细胞因子阵列的研究表明，SNI 模型的 sEVs 中含有独特的蛋白质。与对照相比，我们观察到 SNI 模型的外泌体中 C5a 和 ICAM-1 上调。C5a 和 ICAM-1 在对照和 SNI 之间的外泌体和血清中的分布存在差异，表明信号从局部到远距离发生了转变。我们的研究表明，囊泡蛋白的货物分拣在介导神经性疼痛下的信号中起着关键作用。
