Up-regulation of mRNA for matrix metalloproteinases-9 and-14 in advanced lesions of demyelinating canine distemper leukoencephalitis
Up-regulation of mRNA for matrix metalloproteinases-9 and-14 in advanced lesions of demyelinating canine distemper leukoencephalitis
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DOI：
10.1007/s00401-005-1055-z
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发表时间：
2005-10-01
影响因子：
12.7
通讯作者：
Baumgärtner, W
中科院分区：
文献类型：
--
作者：
Gröters, S;Alldinger, S;Baumgärtner, W
基质金属蛋白酶（MMP）包括蛋白水解锌和钙依赖性酶家族，其能够破坏血脑屏障并介导细胞外基质和髓鞘组分的破坏。MMP还参与促进白细胞迁移到中枢神经系统的炎症部位。为了确定自发性脱髓鞘性犬瘟热脑炎犬中MMP-9、MMP-14和金属蛋白酶组织抑制剂（TIMP-1）的细胞定位和mRNA含量，采用特异性洋地黄毒苷标记的RNA探针通过原位杂交研究了福尔马林固定的石蜡包埋的小脑。此外，进行免疫组织化学以表征脱髓鞘性白质脑炎的不同类型斑块。免疫组化和原位杂交检测病毒抗原和mRNA。健康对照犬在不同数量的神经元、星形胶质细胞、小胶质细胞和少突胶质细胞中显示MMP-9、MMP-14和TIMP-1的mRNA的弱信号。在犬瘟热犬的小脑中，观察到MMP-9、MMP-14和TIMP-1 mRNA表达细胞的数量和染色强度均显著增加，主要见于亚急性炎性病变和慢性斑块。表达MMP-9和MMP-14 mRNA的细胞数量比表达TIMP-1 mRNA的细胞增加约2 - 3倍，而单个细胞的染色强度相似。在早期病变中，特别是星形胶质细胞和活化的巨噬细胞/小胶质细胞显示MMP和TIMP-1的阳性信号，而在老年病变中，活化的小胶质细胞/巨噬细胞和浸润的淋巴细胞代表MMP-9，MMP-14和TIMP-1 mRNA合成的主要来源，如双标记技术所揭示的。总之，MMP mRNA表达细胞的比例较高的增加可能表明MMP/TIMP失衡作为脱髓鞘犬瘟热白质脑炎病变开始和进展的原因。
Matrix metalloproteinases (MMPs) comprise a family of proteolytic zinc- and calcium-dependent enzymes that are capable of disrupting the blood-brain barrier and mediating the destruction of extracellular matrix and myelin components. MMPs are also involved in facilitating leukocyte migration into inflammatory sites of the central nervous system. To determine the cellular localization and the amount of mRNA for MMP-9, MMP-14 and a tissue inhibitor of metalloproteinases (TIMP-1) in dogs with spontaneous demyelinating distemper encephalitis, formalin-fixed paraffin-embedded cerebella were investigated by in situ hybridization using specific digoxigenin-labeled RNA probes. Additionally, immunohistochemistry was performed to characterize the different types of plaques of demyelinating leukoencephalitis. Furthermore, virus antigen and mRNA were detected by immunohistochemistry and in situ hybridization. Healthy control dogs revealed a weak signal for mRNA for MMP-9, MMP-14, and TIMP-1 in various numbers of neurons, astrocytes, microglial cells and oligodendrocytes. In the cerebella of dogs with distemper, a strong increase of both number and staining intensity of MMP-9, MMP-14, and TIMP-1 mRNA-expressing cells, mainly in subacute inflammatory lesions and chronic plaques, was observed. The number of cells expressing mRNA for MMP-9 and MMP-14 increased about two- to threefold compared to TIMP-1 mRNA-expressing cells, whereas staining intensity of individual cells was similar. In early lesions, especially astrocytes and activated macrophages/microglial cells displayed a positive signal for MMPs and TIMP-1, whereas in older lesions activated microglia/macrophages and infiltrating lymphocytes represented the main source for MMP-9, MMP-14, and TIMP-1 mRNA synthesis as revealed by double-labeling techniques. In summary, the proportionally higher increase of MMP mRNA-expressing cells might indicate an MMP/TIMP imbalance as a cause for lesion initiation and progression in demyelinating canine distemper leukoencephalitis.