Lanning C L, Wilmarth K R, Abou-Donia M B
Department of Pharmacology, Duke University Medical Center, Durham, North Carolina 27710.
Neurochem Res. 1994 Sep;19(9):1165-73. doi: 10.1007/BF00965151.
2,5-Hexanedione (2,5-HD) induces central-peripheral axonpathy characterized by the accumulation of 10-nm neurofilaments proximal to the nodes of Ranvier and a Wallerian-type degeneration. It has been postulated that neurofilament crosslinking may be involved in the production of this axonopathy. A potential initiating event in this neurotoxic process may be the direct binding of 2,5-HD to neurofilament and microtubule proteins. In this study, the in vitro binding of [14C]2,5-HD to neurofilament and microtubule proteins was examined. Neurofilament proteins isolated from rat spinal cord or microtubule proteins isolated from rat brain were incubated in the presence of 2,5-HD at concentrations ranging from 25 to 500 mM. Quantitative analysis of sodium dodecyl sulfate (SDS) polyacrylamide gels revealed a dose- and time-dependent binding of 2,5-HD to both neurofilament proteins and microtubule proteins. Expressed as pmol 2,5-HD bound per microgram protein, the observed relative binding was MAP2 > NF160 > NF200 > > NF68 > tubulin. These data demonstrate the direct binding of 2,5-HD to cytoskeletal proteins including both neurofilaments and microtubules.
2,5-己二酮（2,5-HD）可引发中枢-外周轴索性神经病，其特征为郎飞结近端10纳米神经丝的积聚以及华勒氏型变性。据推测，神经丝交联可能参与了这种轴索性神经病的发生。此神经毒性过程中一个潜在的起始事件可能是2,5-HD与神经丝和微管蛋白的直接结合。在本研究中，检测了[14C]2,5-HD与神经丝和微管蛋白的体外结合情况。将从大鼠脊髓分离的神经丝蛋白或从大鼠脑分离的微管蛋白在浓度范围为25至500 mM的2,5-HD存在下孵育。十二烷基硫酸钠（SDS）聚丙烯酰胺凝胶的定量分析显示，2,5-HD与神经丝蛋白和微管蛋白的结合呈剂量和时间依赖性。以每微克蛋白结合的2,5-HD皮摩尔数表示，观察到的相对结合情况为微管相关蛋白2（MAP2）>神经丝蛋白160（NF160）>神经丝蛋白200（NF200）>>神经丝蛋白68（NF68）>微管蛋白。这些数据证明了2,5-HD与包括神经丝和微管在内的细胞骨架蛋白的直接结合。
