Tucholski J, Lesort M, Johnson G V
Department of Psychiatry and Behavioral Neurobiology, 1720 7th Ave. South, SC 1061, University of Alabama at Birmingham, AL 35294-0017, Birmingham, USA.
Neuroscience. 2001;102(2):481-91. doi: 10.1016/s0306-4522(00)00482-6.
Tissue transglutaminase is a normal constituent of the central and peripheral nervous systems and in rats transglutaminase activity in brain and spinal cord is highest during fetal stages when axonal outgrowth is occurring. Further, treatment of human neuroblastoma SH-SY5Y cells with retinoic acid results in the cells withdrawing from the cell cycle and extending neurites, in the same time frame that tissue transglutaminase expression significantly increases. Considering these and other previous findings, this study was carried out to determine whether tissue transglutaminase is involved in neuronal differentiation of SH-SY5Y cells. For these studies SH-SY5Y cells stably overexpressing wild-type tissue transglutaminase, an inactive tissue transglutaminase mutant (C277S) or an antisense tissue transglutaminase construct (which decreased endogenous tissue transglutaminase below detectable levels) were used. SH-SY5Y cells overexpressing wild-type tissue transglutaminase spontaneously differentiated into a neuronal phenotype when grown in low-serum media. In contrast, cells overexpressing inactive tissue transglutaminase or the antisense tissue transglutaminase continued to proliferate and exhibit a flat polygenic morphology even when maintained in low-serum conditions. In addition, increased tissue transglutaminase expression in response to retinoic acid was abolished in the antisense tissue transglutaminase cells, and antisense and mutant tissue transglutaminase expressing cells did not extend neurites in response to retinoic acid. Moreover, wild-type and inactive tissue transglutaminase exhibited differential intracellular localization. These data indicate that tissue transglutaminase is necessary and sufficient for neuronal differentiation of human neuroblastoma SH-SY5Y cells.
组织转谷氨酰胺酶是中枢和外周神经系统的正常组成部分，在大鼠中，脑和脊髓中的转谷氨酰胺酶活性在轴突生长的胎儿阶段最高。此外，用视黄酸处理人神经母细胞瘤SH-SY5Y细胞会导致细胞退出细胞周期并长出神经突，与此同时组织转谷氨酰胺酶的表达显著增加。考虑到这些及其他先前的研究结果，本研究旨在确定组织转谷氨酰胺酶是否参与SH-SY5Y细胞的神经元分化。对于这些研究，使用了稳定过表达野生型组织转谷氨酰胺酶、无活性的组织转谷氨酰胺酶突变体（C277S）或反义组织转谷氨酰胺酶构建体（其将内源性组织转谷氨酰胺酶降低到可检测水平以下）的SH-SY5Y细胞。在低血清培养基中生长时，过表达野生型组织转谷氨酰胺酶的SH-SY5Y细胞会自发分化为神经元表型。相比之下，过表达无活性组织转谷氨酰胺酶或反义组织转谷氨酰胺酶的细胞即使在低血清条件下仍继续增殖并呈现扁平的多基因形态。此外，反义组织转谷氨酰胺酶细胞中视黄酸诱导的组织转谷氨酰胺酶表达增加被消除，并且表达反义及突变组织转谷氨酰胺酶的细胞对视黄酸无神经突延伸反应。此外，野生型和无活性组织转谷氨酰胺酶表现出不同的细胞内定位。这些数据表明，组织转谷氨酰胺酶对于人神经母细胞瘤SH-SY5Y细胞的神经元分化是必要且充分的。
