Expression of two temporally distinct microglia-related gene clusters after spinal cord injury
Expression of two temporally distinct microglia-related gene clusters after spinal cord injury
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作者：
Byrnes, KR;Garay, J;Faden, AI
小胶质细胞在细胞毒性和神经保护中的双重作用被认为取决于小胶质细胞相关基因的特异性、时间性表达。为了更好地阐明这一问题，我们使用高密度寡核苷酸微阵列检测大鼠脊髓损伤（SCI）后小胶质细胞基因的表达。我们比较了轻度、中度或重度SCI后病变部位以及头端和尾端区域的表达变化。使用小胶质细胞相关的锚基因，我们确定了两个集群具有不同的时间配置文件。第一种是在损伤后4小时诱导的，在4和24小时之间达到峰值，包括白细胞介素-1 β、白细胞介素-6、骨桥蛋白和钙颗粒蛋白等。第二个是在SCI后24小时诱导的，在72小时和7天之间达到峰值;它包括C1 qB，Galectin-3和p22（phox）。无论损伤严重程度如何，这两个簇显示出相似的表达谱，尽管与中度损伤相比，轻度或重度损伤中的表达略有降低。表达也下降的病变部位的吻侧和尾侧。我们在mRNA和蛋白质水平验证了所选簇成员的表达。此外，我们证明了在培养中刺激纯化的小胶质细胞诱导C1 qB，半乳糖凝集素-3和p22（phox）的表达。最后，抑制P22（phox）活性的小胶质细胞培养物中显着抑制增殖的刺激，证实该基因参与小胶质细胞活化。由于小胶质细胞相关因素已牵连在继发性损伤和恢复，识别时间上不同的集群相关的小胶质细胞激活基因可能表明这些组的因素的不同作用。(c)2005 Wiley-Liss，Inc.
The dual role of microglia in cytotoxicity and neuroprotection is believed to depend on the specific, temporal expression of microglial-related genes. To better clarify this issue, we used high-density oligonucleotide microarrays to examine microglial gene expression after spinal cord injury (SCI) in rats. We compared expression changes at the lesion site, as well as in rostral and caudal regions after mild, moderate, or severe SCI. Using microglial-associated anchor genes, we identified two clusters with different temporal profiles. The first, induced by 4 h postinjury to peak between 4 and 24 h, included interieukin-1 beta, interleukin-6, osteopontin, and calgranulin, among others. The second was induced 24 h after SCI, and peaked between 72 h and 7 days; it included C1qB, Galectin-3, and p22(phox). These two clusters showed similar expression profiles regardless of injury severity, albeit with slight decreases in expression in mild or severe injury vs. moderate injury. Expression was also decreased rostral and caudal to the lesion site. We validated the expression of selected cluster members at the mRNA and protein levels. In addition, we demonstrated that stimulation of purified microglia in culture induces expression of C1qB, Galectin-3, and p22(phox). Finally, inhibition of P22(phox) activity within microglial cultures significantly suppressed proliferation in response to stimulation, confirming that this gene is involved in microglial activation. Because microglial-related factors have been implicated both in secondary injury and recovery, identification of temporally distinct clusters of genes related to microglial activation may suggest distinct roles for these groups of factors. (c) 2005 Wiley-Liss, Inc.