Dominov Janice A, Kravetz Amanda J, Ardelt Magdalena, Kostek Christine A, Beermann Mary Lou, Miller Jeffrey B
Boston Biomedical Research Institute, 64 Grove Street, Watertown, MA 02472, USA.
Hum Mol Genet. 2005 Apr 15;14(8):1029-40. doi: 10.1093/hmg/ddi095. Epub 2005 Mar 9.
To examine the role of apoptosis in neuromuscular disease progression, we have determined whether pathogenesis in dystrophin-deficient (mdx) and laminin alpha2-deficient (Lama2-null) mice is ameliorated by overexpression of the anti-apoptosis protein BCL2 in diseased muscles. The mdx mice are a model for the human disease, Duchenne muscular dystrophy (DMD), and the Lama2-null mice are a model for human congenital muscular dystrophy type 1A (MDC1A). For these studies, we generated transgenic mice that overexpressed human BCL2 under control of muscle-specific MyoD or MRF4 promoter fragments. We then used cross-breeding to introduce the transgenes into diseased mdx or Lama2-null mice. In mdx mice, we found that overexpression of BCL2 failed to produce any significant differences in muscle pathology. In contrast, in the Lama2-null mice, we found that muscle-specific expression of BCL2 led to a several-fold increase in lifespan and an increased growth rate. Thus, BCL2-mediated apoptosis appears to play a significant role in pathogenesis of laminin alpha2 deficiency, but not of dystrophin deficiency, suggesting that therapies designed to ameliorate disease by inhibition of apoptosis are more likely to succeed in MDC1A than in DMD.
为了研究细胞凋亡在神经肌肉疾病进展中的作用,我们确定了在患病肌肉中过表达抗凋亡蛋白BCL2是否能改善肌营养不良蛋白缺陷(mdx)小鼠和层粘连蛋白α2缺陷(Lama2基因敲除)小鼠的发病机制。mdx小鼠是人类杜氏肌营养不良症(DMD)的模型,而Lama2基因敲除小鼠是人类1A型先天性肌营养不良症(MDC1A)的模型。在这些研究中,我们构建了在肌肉特异性MyoD或MRF4启动子片段控制下过表达人BCL2的转基因小鼠。然后通过杂交将转基因导入患病的mdx或Lama2基因敲除小鼠中。在mdx小鼠中,我们发现BCL2的过表达在肌肉病理学上未产生任何显著差异。相反,在Lama2基因敲除小鼠中,我们发现BCL2的肌肉特异性表达使寿命延长了几倍,并提高了生长速率。因此,BCL2介导的细胞凋亡似乎在层粘连蛋白α2缺乏的发病机制中起重要作用,但在肌营养不良蛋白缺乏的发病机制中不起作用,这表明旨在通过抑制细胞凋亡来改善疾病的疗法在MDC1A中比在DMD中更有可能成功。