钙调神经磷酸酶信号通路的激活可减轻mdx小鼠的营养不良病理症状。
Stimulation of calcineurin signaling attenuates the dystrophic pathology in mdx mice.
作者信息
Chakkalakal Joe V, Harrison Mary-Ann, Carbonetto Salvatore, Chin Eva, Michel Robin N, Jasmin Bernard J
机构信息
Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
出版信息
Hum Mol Genet. 2004 Feb 15;13(4):379-88. doi: 10.1093/hmg/ddh037. Epub 2003 Dec 17.
Utrophin has been studied extensively in recent years in an effort to find a cure for Duchenne muscular dystrophy. In this context, we previously showed that mice expressing enhanced muscle calcineurin activity (CnA*) displayed elevated levels of utrophin around their sarcolemma. In the present study, we therefore crossed CnA* mice with mdx mice to determine the suitability of elevating calcineurin activity in preventing the dystrophic pathology. Muscles from mdx/CnA* displayed increased nuclear localization of NFATc1 and a fiber type shift towards a slower phenotype. Measurements of utrophin levels in mdx/CnA* muscles revealed an approximately 2-fold induction in utrophin expression. Consistent with this induction, we also observed that members of the dystrophin-associated protein (DAP) complex were present at the sarcolemma of mdx/CnA* mouse muscle. This restoration of the utrophin-DAP complex was accompanied by significant reductions in the extent of central nucleation and fiber size variability. Importantly, assessment of myofiber sarcolemmal damage, as monitored by the intracellular presence of IgM and albumin as well as by Evans blue uptake in vivo, revealed a net amelioration of membrane integrity. Finally, immunofluorescence experiments using Mac-1 antibodies showed a reduction in the number of infiltrating immune cells in muscles from mdx/CnA* mice. These results show that elevated calcineurin activity attenuates the dystrophic pathology and thus provides an effective target for pharmacological intervention.
近年来,为了找到杜氏肌营养不良症的治疗方法,人们对肌养蛋白进行了广泛研究。在此背景下,我们之前发现,表达增强型肌肉钙调神经磷酸酶活性(CnA*)的小鼠在其肌膜周围的肌养蛋白水平升高。因此,在本研究中,我们将CnA小鼠与mdx小鼠杂交,以确定提高钙调神经磷酸酶活性在预防营养不良病理方面的适用性。mdx/CnA小鼠的肌肉显示NFATc1的核定位增加,纤维类型向更慢的表型转变。对mdx/CnA小鼠肌肉中肌养蛋白水平的测量显示,肌养蛋白表达增加了约2倍。与这种诱导一致,我们还观察到肌营养不良蛋白相关蛋白(DAP)复合物的成员存在于mdx/CnA小鼠肌肉的肌膜上。肌养蛋白-DAP复合物的这种恢复伴随着中央成核程度和纤维大小变异性的显著降低。重要的是,通过体内IgM和白蛋白的细胞内存在以及伊文思蓝摄取监测的肌纤维肌膜损伤评估显示,膜完整性有净改善。最后,使用Mac-1抗体的免疫荧光实验表明,mdx/CnA*小鼠肌肉中浸润免疫细胞的数量减少。这些结果表明,升高的钙调神经磷酸酶活性减轻了营养不良病理,因此为药物干预提供了一个有效的靶点。