Colsch Benoit, Jackson Shelley N, Dutta Sucharita, Woods Amina S
Structural Biology Unit, Cellular Neurobiology Section, NIDA IRP, NIH, Baltimore, Maryland 21224, United States.
ACS Chem Neurosci. 2011 Feb 21;2(4):213-222. doi: 10.1021/cn100096h.
Gangliosides are amphiphilic molecules found in the outer layer of plasma membranes of all vertebrate cells. They play a major role in cell recognition and signaling and are involved in diseases affecting the central nervous system (CNS). We are reporting the differential distribution of ganglioside species in the rat brain's cerebrum, based on their ceramide associated core, and for the first time the presence of acetylation detected by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, which was used to map and image gangliosides with detailed structural information and histological accuracy. In the hippocampus, localization of the major species GM1, GD1, O-acetylGD1, GT1, and O-acetylGT1 depends on the sphingoïd base (d18:1 sphingosine or d20:1 eïcosasphingosine) in the molecular layer of the dentate gyrus (ML), which is made up of three distinct layers, the inner molecular layer (IML), which contains sphingosine exclusively, and the middle molecular layer (MML) and the outer molecular layer (OML) where eïcosasphingosine is the only sphingoïd base. These results demonstrate that there is a different distribution of gangliosides in neuronal axons and dendrites depending on the ceramide core of each layer. GM3, GM2, GD3, and GD2 contain sphingosine predominantly and are mainly present in body cell layers, which are made up of the pyramidal cell layer (Py) and the granular layer of the dentate gyrus (GL), in contrast with GQ1 and the O-acetylated forms of GD1, GT1, and GQ1 gangliosides, which contain both sphingoïd bases. However their distribution is based on the sialylated and acetylated oligosaccharide chains in the neuronal cell bodies.
神经节苷脂是一类两亲性分子，存在于所有脊椎动物细胞的质膜外层。它们在细胞识别和信号传导中起主要作用，并与影响中枢神经系统（CNS）的疾病有关。我们报告了基于其神经酰胺相关核心的神经节苷脂种类在大鼠大脑皮层中的差异分布，并且首次通过基质辅助激光解吸/电离（MALDI）质谱法检测到乙酰化的存在，该方法用于绘制具有详细结构信息和组织学准确性的神经节苷脂图谱并成像。在海马体中，主要种类GM1、GD1、O - 乙酰基GD1、GT1和O - 乙酰基GT1的定位取决于齿状回分子层（ML）中的鞘氨醇碱基（d18:1鞘氨醇或d20:1二十碳鞘氨醇），该分子层由三个不同的层组成，即仅含有鞘氨醇的内分子层（IML），以及以二十碳鞘氨醇为唯一鞘氨醇碱基的中分子层（MML）和外分子层（OML）。这些结果表明，根据每层的神经酰胺核心，神经节苷脂在神经元轴突和树突中的分布不同。GM3、GM2、GD3和GD2主要含有鞘氨醇，主要存在于体细胞层，体细胞层由锥体细胞层（Py）和齿状回颗粒层（GL）组成，这与含有两种鞘氨醇碱基的GQ1以及GD1、GT1和GQ1神经节苷脂的O - 乙酰化形式形成对比。然而，它们的分布基于神经元细胞体中的唾液酸化和乙酰化寡糖链。
