Berger U V, Carter R E, McKee M, Coyle J T
Laboratory of Molecular and Developmental Neuroscience, Massachusetts General Hospital East, Charlestown 02129, USA.
J Neurocytol. 1995 Feb;24(2):99-109. doi: 10.1007/BF01181553.
N-acetylated alpha-linked acidic dipeptidase is a membrane-bound brain peptidase which cleaves the neuropeptide N-acetyl-aspartyl-glutamate to N-acetyl-aspartate and glutamate. In the present study, we have determined the localization of N-acetylated alpha-linked acidic dipeptidase in the peripheral nervous system. Using enzyme assays and immunoblotting, we demonstrate that sciatic nerve, phrenic nerve, cervical dorsal root ganglion and superior cervical ganglion contain N-acetylated alpha-linked acidic dipeptidase activity as well as an N-acetylated alpha-linked acidic dipeptidase-like protein. Furthermore, we show that N-acetylated alpha-linked acidic dipeptidase-like immunoreactivity is extensively co-localized in peripheral nerves with immunoreactivity for glial fibrillary acidic protein, a known marker for non-myelinating Schwann cells. Using electron microscopy, we demonstrate N-acetylated alpha-linked acidic dipeptidase-like immunoreactivity in cell membranes of non-myelinating Schwann cells in the superior cervical ganglion. These results show that N-acetylated alpha-linked acidic dipeptidase is expressed in the peripheral nervous system by non-myelinating Schwann cells. This cellular localization suggests that N-acetylated alpha-linked acidic dipeptidase may be involved in the signalling between axons and Schwann cells, for example during development or regeneration.
N-乙酰化α-连接酸性二肽酶是一种膜结合脑肽酶，可将神经肽N-乙酰天冬氨酰谷氨酸裂解为N-乙酰天冬氨酸和谷氨酸。在本研究中，我们确定了N-乙酰化α-连接酸性二肽酶在外周神经系统中的定位。通过酶活性测定和免疫印迹，我们证明坐骨神经、膈神经、颈背根神经节和颈上神经节含有N-乙酰化α-连接酸性二肽酶活性以及一种N-乙酰化α-连接酸性二肽酶样蛋白。此外，我们发现N-乙酰化α-连接酸性二肽酶样免疫反应性在外周神经中与胶质纤维酸性蛋白（一种已知的非髓鞘雪旺细胞标志物）的免疫反应性广泛共定位。通过电子显微镜，我们在颈上神经节的非髓鞘雪旺细胞的细胞膜中证明了N-乙酰化α-连接酸性二肽酶样免疫反应性。这些结果表明，N-乙酰化α-连接酸性二肽酶由非髓鞘雪旺细胞在外周神经系统中表达。这种细胞定位表明，N-乙酰化α-连接酸性二肽酶可能参与轴突与雪旺细胞之间的信号传导，例如在发育或再生过程中。
