Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Taiwan.
J Neurotrauma. 2009 Dec;26(12):2345-53. doi: 10.1089/neu.2009.0960.
MicroRNAs (miRNAs) are a class of highly conserved, non-coding RNAs involved in post-transcriptional gene regulation. The muscle-specific miRNAs, miR-1, miR-133a, and miR-206, are expressed in skeletal muscles and have been shown to contribute to muscle development. To profile their expression after sciatic nerve denervation and reinnervation, the soleus muscles of the rats were analyzed with quantitative real-time PCR at 1 week, 1 month, 2 months, and 4 months after the experiments. In addition, a combined approach using computational prediction by the miRanda website and the Agilent Whole Rat Genome 4 x 44 k oligo microarray experiment was performed to investigate the potential target genes of these three miRNAs in the denervated and reinnervated muscles. The results revealed that with the first downregulation of miR-1 and miR-133a within 1 month in the denervated muscle, the expression of miR-1 and miR-133 increased by approximately 2-fold at 4 months after denervation and reinnervation; on the other hand, the expression of miR-206 was significantly increased to approximately 3-fold 1 month later only following reinnervation but not following denervation, and lasted at least for 4 months. The expression pattern of miR-206 was different from that of miR-1 and miR-133a. Notably, two genes (Hnrpu and Npy) and one gene (Ptprd) were potentially regulated both in the denervated and reinnervated muscle by miR-1 and miR-133a, respectively. There were six potential target genes (Hnrpu, Lsamp, MGC108776, Mef2, Npy, and Ppfibp2) of the upregulated miR-206 in the reinnervated muscle. Among these, three (Hnrpu, Npy, and MGC108776) were potentially regulated by both miR-1 and miR-206. Because the Mef2 transcription factor was reported to promote the transformation of type II fast glycolytic fibers into type I slow oxidative fibers, the upregulation of miR-206 with decreased expression of the Mef2 transcript in the 4 month reinnervated muscle, which presented type II fiber predominance 4 months after nerve microanastomosis, might indicate the role of miR-206 in determining the fiber type after peripheral nerve regeneration.
微小 RNA（miRNAs）是一类高度保守的非编码 RNA，参与转录后基因调控。肌肉特异性 miRNAs，miR-1、miR-133a 和 miR-206，在骨骼肌中表达，并被证明有助于肌肉发育。为了分析坐骨神经切断和再支配后它们的表达情况，用定量实时 PCR 分析了实验后 1 周、1 个月、2 个月和 4 个月大鼠比目鱼肌的表达。此外，还采用了 miRanda 网站的计算预测和安捷伦全大鼠基因组 4 x 44 k oligo 微阵列实验的组合方法，研究了这三种 miRNAs 在去神经和再神经支配肌肉中的潜在靶基因。结果表明，在去神经肌肉中 miR-1 和 miR-133a 的第一个下调发生在 1 个月内，去神经和再神经支配后 4 个月 miR-1 和 miR-133 的表达增加了约 2 倍；另一方面，miR-206 的表达仅在再神经支配后 1 个月显著增加约 3 倍，而在去神经支配后则没有，并且至少持续 4 个月。miR-206 的表达模式与 miR-1 和 miR-133a 不同。值得注意的是，两个基因（Hnrpu 和 Npy）和一个基因（Ptprd）分别由 miR-1 和 miR-133a 共同调节，在去神经和再神经支配的肌肉中都是潜在的调节因子。在再神经支配的肌肉中，有六个上调的 miR-206 的潜在靶基因（Hnrpu、Lsamp、MGC108776、Mef2、Npy 和 Ppfibp2）。其中，三个（Hnrpu、Npy 和 MGC108776）受 miR-1 和 miR-206 的共同调节。因为报道称 Mef2 转录因子促进 II 型快速糖酵解纤维向 I 型缓慢氧化纤维的转化，所以在神经微吻合后 4 个月再神经支配的肌肉中，miR-206 的上调伴随着 Mef2 转录本的表达减少，而 4 个月后表现出 II 型纤维优势，这可能表明 miR-206 在决定周围神经再生后的纤维类型方面发挥作用。
