Bayer School of Natural and Environmental Sciences, Duquesne University, Pittsburgh, PA, USA.
Department of Biological Sciences, Duquesne University, Pittsburgh, PA, USA.
Mol Pain. 2020 Jan-Dec;16:1744806920943309. doi: 10.1177/1744806920943309.
Chronic constriction injury of the sciatic nerve in rats causes peripheral neuropathy leading to pain-like behaviors commonly seen in humans. Neuropathy is a leading cause of neuropathic pain, which involves a complex cellular and molecular response in the peripheral nervous system with interactions between neurons, glia, and infiltrating immune cells. In this study, we utilize a nonsteroidal anti-inflammatory drug -loaded nanoemulsion to deliver the cyclooxygenase-2 inhibitor, Celecoxib, directly to circulating monocytes following nerve injury, which provides long-lasting pain relief. However, it is not fully understood how cyclooxygenase-2 inhibition in a macrophage traveling to the site of injury impacts gene expression in the dorsal root ganglia. To elucidate aspects of the molecular mechanisms underlying pain-like behavior in chronic constriction injury, as well as subsequent pain relief with treatment, we employ RNAseq transcriptome profiling of the dorsal root ganglia associated with the injured sciatic nerve in rats. Using high throughput RNA sequencing in this way provides insight into the molecular mechanisms involved in this neuroinflammatory response. We compare the transcriptome from the dorsal root ganglias of the following study groups: chronic constriction injury animals administered with cyclooxygenase-2 inhibiting celecoxib-loaded nanoemulsion, chronic constriction injury animals administered with vehicle treatment, a drug-free nanoemulsion, and a group of naïve, unoperated and untreated rats. The results show an extensive differential expression of 115 genes. Using the protein annotation through evolutionary relationship classification system, we have revealed pain-related signaling pathways and underlying biological mechanisms involved in the neuroinflammatory response. Quantitative polymerase chain reaction validation confirms expression changes for several genes. This study shows that by directly inhibiting cyclooxygenase-2 activity in infiltrating macrophages at the injured sciatic nerve, there is an associated change in the transcriptome in the cell bodies of the dorsal root ganglia.
大鼠坐骨神经慢性缩窄性损伤导致周围神经病变，引起类似人类的疼痛行为。神经病变是神经病理性疼痛的主要原因，涉及外周神经系统中神经元、神经胶质细胞和浸润免疫细胞之间的复杂细胞和分子反应。在这项研究中，我们利用载有环氧化酶-2 抑制剂塞来昔布的非甾体抗炎药纳米乳液，在神经损伤后直接将其递送至循环单核细胞，从而提供持久的镇痛作用。然而，尚不完全清楚在损伤部位迁移的巨噬细胞中环氧化酶-2 抑制如何影响背根神经节中的基因表达。为了阐明慢性缩窄性损伤中类似疼痛行为的分子机制以及随后治疗的疼痛缓解，我们采用 RNAseq 转录组谱分析与损伤的大鼠坐骨神经相关的背根神经节。通过这种高通量 RNA 测序方法，可以深入了解神经炎症反应所涉及的分子机制。我们比较了以下研究组的背根神经节转录组：给予载有环氧化酶-2 抑制剂塞来昔布的纳米乳液的慢性缩窄性损伤动物、给予载体处理的慢性缩窄性损伤动物、无药物纳米乳液和一组未经手术和未治疗的正常大鼠。结果显示 115 个基因的表达广泛差异。通过进化关系分类系统的蛋白质注释，我们揭示了与神经炎症反应相关的疼痛相关信号通路和潜在的生物学机制。定量聚合酶链反应验证证实了几个基因的表达变化。这项研究表明，通过直接抑制损伤坐骨神经处浸润巨噬细胞中的环氧化酶-2 活性，背根神经节细胞体中的转录组会发生相关变化。
