Department of Physiology, East Carolina University, Greenville, NC 27834, USA.
Neuroscience. 2011 Sep 8;190:386-97. doi: 10.1016/j.neuroscience.2011.06.017. Epub 2011 Jun 12.
Recently, functional and potent RNA interference (RNAi) has been reported in peripheral nerve axons transfected with short-interfering RNA (siRNA). In addition, components of RNA-induced silencing complex (RISC) have been identified in axotomized sciatic nerve fibers as well as in regenerating dorsal root ganglia (DRG) neurons in vitro. Based on these observations, and on the fact that siRNA and microRNA (miRNA) share the same effector enzymes, we hypothesized that the endogenous miRNA biosynthetic pathway would respond to peripheral nerve injury. To answer this question, we investigated changes in the expression of miRNA biosynthetic enzymes following peripheral nerve crush injury in mice. Here, we show that several pivotal miRNA biosynthetic enzymes are expressed in an injury-regulated pattern in sciatic nerve in vivo, and in DRG axons in vitro. Moreover, the sciatic nerve lesion induced expression of mRNA-processing bodies (P-bodies), which are the local foci of mRNA degradation in DRG axons. In addition, a group of injury-regulated miRNAs was identified by miRNA microarray and validated by real-time quantitative PCR (qPCR) and in situ hybridization analyses. Taken together, our data support the hypothesis that the peripheral nerve regeneration processes may be regulated by miRNA pathway.
最近，在经过短干扰 RNA（siRNA）转染的周围神经轴突中报道了功能强大的 RNA 干扰（RNAi）。此外，在轴突切断的坐骨神经纤维以及体外再生的背根神经节（DRG）神经元中，已经鉴定出 RNA 诱导沉默复合物（RISC）的成分。基于这些观察结果，以及 siRNA 和 microRNA（miRNA）共享相同的效应酶这一事实，我们假设内源性 miRNA 生物合成途径会对周围神经损伤做出反应。为了回答这个问题，我们研究了 miRNA 生物合成酶在小鼠周围神经挤压损伤后的表达变化。在这里，我们表明，几种关键的 miRNA 生物合成酶在体内坐骨神经和体外 DRG 轴突中以损伤调节的模式表达。此外，坐骨神经损伤诱导了 mRNA 处理体（P 体）的表达，P 体是 DRG 轴突中 mRNA 降解的局部焦点。此外，通过 miRNA 微阵列鉴定了一组损伤调节的 miRNA，并通过实时定量 PCR（qPCR）和原位杂交分析进行了验证。总之，我们的数据支持这样的假设，即周围神经再生过程可能受 miRNA 通路调控。
