Cacic M, Sostarić K, Weber-Schürholz S, Müthing J
Department of Chemistry and Biochemistry, School of Medicine, University of Zagreb, Croatia.
Glycoconj J. 1995 Oct;12(5):721-8. doi: 10.1007/BF00731270.
The expression of neutral glycosphingolipids (GSLs) and gangliosides was investigated in cryosections of normal mouse skeletal muscle and in muscle of mice with neuromuscular diseases using indirect immunofluorescence microscopy. Transversal and longitudinal sections were immunostained with specific polyclonal antibodies against lactosylceramide, lacto-N-neotetraosylceramide, globoside, GM3(Neu5Ac), GM3(Neu5Gc) and Gm1(Neu5Ac) as well as monoclonal anti-Forssman GSL antibody. In normal CBA/J mouse muscle (control) the main immunohistochemically detected ganglioside was GM3(Neu5Ac) followed by moderately expressed GM3(Neu5Gc) and GM1. The neutral GSLs lactosylceramide and globoside were stained with almost identical, high fluorescence intensity. Low amounts of lacto-N-neotetraosylceramide and trace quantities of Forssman GSL were immunostained. All GSLs were detected in the sarcolemma, but also in considerable amounts at the intracellular level. Mice with neuromuscular diseases were the A2G-adr mouse mutant (a model for human recessive myotonia of Becker type), the BL6-wr mutant (a model for motor neuron disease) and the BL10-mdx mouse mutant (a model for human Duchenne muscular dystrophy). No changes in GSL expression were found in the A2G-adr mouse, while muscle of the BL6-wr mouse showed increased intensity of immunofluorescence in stainings with anti-lactosylceramide and anti-GM3(Neu5Ac) antibodies. Muscle of BL10-mdx mice showed the most prominent changes in GSL expression with reduced fluorescence intensity for all antibodies. Major differences were not observed in the intensities of GSLs, but there were significant differences in the patterns of distribution on plasma membrane and at the subcellular level. The exact nature and pathogenesis of these changes should be elucidated since such investigations could furnish advances in understanding the functional role of neutral GSLs and gangliosides in normal as well as in diseased muscle.
采用间接免疫荧光显微镜技术，对正常小鼠骨骼肌冰冻切片以及患有神经肌肉疾病的小鼠肌肉中中性糖鞘脂（GSLs）和神经节苷脂的表达进行了研究。横向和纵向切片用抗乳糖基神经酰胺、乳糖 - N - 新四糖基神经酰胺、红细胞糖苷脂、GM3（Neu5Ac）、GM3（Neu5Gc）和Gm1（Neu5Ac）的特异性多克隆抗体以及抗福斯曼GSL单克隆抗体进行免疫染色。在正常CBA/J小鼠肌肉（对照）中，免疫组化检测到的主要神经节苷脂是GM3（Neu5Ac），其次是中度表达的GM3（Neu5Gc）和GM1。中性GSLs乳糖基神经酰胺和红细胞糖苷脂染色时荧光强度几乎相同且很高。低量的乳糖 - N - 新四糖基神经酰胺和微量的福斯曼GSL被免疫染色。所有GSLs在肌膜中均有检测到，但在细胞内水平也有相当数量。患有神经肌肉疾病的小鼠有A2G - adr小鼠突变体（人类贝克尔型隐性肌强直模型）、BL6 - wr突变体（运动神经元疾病模型）和BL10 - mdx小鼠突变体（人类杜兴氏肌营养不良模型）。在A2G - adr小鼠中未发现GSL表达变化，而BL6 - wr小鼠的肌肉在用抗乳糖基神经酰胺和抗GM3（Neu5Ac）抗体染色时免疫荧光强度增加。BL10 - mdx小鼠的肌肉在GSL表达上变化最为显著，所有抗体染色的荧光强度均降低。未观察到GSLs强度的主要差异，但在质膜和亚细胞水平的分布模式上存在显著差异。这些变化的确切性质和发病机制应予以阐明，因为此类研究可能有助于推进对中性GSLs和神经节苷脂在正常及患病肌肉中功能作用的理解。
