title: N-acetylated alpha-linked acidic dipeptidase is expressed by non-myelinating Schwann cells in the peripheral nervous system.
abstract: 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.
authors.affiliation: Laboratory of Molecular and Developmental Neuroscience, Massachusetts General Hospital East, Charlestown 02129, USA.
authors.forename: U V
authors.initials: UV
authors.lastname: Berger
authors.forename: R E
authors.initials: RE
authors.lastname: Carter
authors.forename: M
authors.initials: M
authors.lastname: McKee
authors.forename: J T
authors.initials: JT
authors.lastname: Coyle
mesh_terms: D000818:Animals; D004150:Dipeptidases / Q000032:analysis*; D005455:Fluorescent Antibody Technique; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D043425:Glutamate Carboxypeptidase II; D006168:Guinea Pigs; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D017933:Peripheral Nervous System / Q000201:enzymology* / Q000648:ultrastructure; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D012583:Schwann Cells / Q000737:chemistry / Q000201:enzymology*
chemical_list: D005904:Glial Fibrillary Acidic Protein; D004150:Dipeptidases; D043425:Glutamate Carboxypeptidase II