title: Immunoreactivity for beta/A4 protein, but not for its precursor, in human chromaffin cells.
abstract: The present study was designed to establish a) whether chromaffin cells of the human adrenal medulla express immunoreactivity for beta-amyloid precursor protein (beta APP) and/or beta-amyloid protein (beta/A4); and b) whether cells expressing one or both of the above-mentioned proteins display immunoreactivity for the low- (gp75) and/or the high-affinity (gp140-trkA) nerve growth factor receptor. To identify chromaffin cells and their supporting cells, chromogranin A, neurofilament proteins, and S-100 protein were studied in parallel. Beta APP and beta/A4 immunoreactivity (IR) was observed primarily labeling two different cell populations, without colocalization: Beta APP IR was found in the adrenal cortical cells, which were mainly localized in the reticulate layer and in the blood vessel walls, whereas beta/A4 IR was observed in the chromaffin cells. Furthermore, supporting cells were also immunoreactive for beta/A4, and sympathetic ganglionic cells were immunoreactive for both beta APP and beta/A4. Interestingly, clusters of cells expressing beta/A4 IR also displayed gp 75 IR and/or gp140-trkA IR. Finally, all chromaffin cells (identified by chromogranin A IR) were immunolabeled for the 200 kDa neurofilament subunit, but not for a phosphorylated epitope of this protein. These results demonstrate the occurrence of beta/A4 IR, but not of beta APP, in the chromaffin cells of the human adrenal gland. The complementary distribution of amyloid-related proteins, and the possible involvement of neurotrophins in beta/A4 metabolism are discussed.
authors.affiliation: Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Spain.
authors.forename: V L
authors.initials: VL
authors.lastname: Alonso-Cortina
authors.forename: L O
authors.initials: LO
authors.lastname: González-Vázquez
authors.forename: A
authors.initials: A
authors.lastname: Cabal
authors.forename: I
authors.initials: I
authors.lastname: Esteban
authors.lastname: Del Valle
authors.forename: J A
authors.initials: JA
authors.lastname: Vega
mesh_terms: D000368:Aged; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D002838:Chromaffin System / Q000166:cytology / Q000378:metabolism*; D053379:Chromogranin A; D002864:Chromogranins / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D016900:Neurofilament Proteins / Q000096:biosynthesis; D009474:Neurons / Q000378:metabolism; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism; D009418:S100 Proteins / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D053379:Chromogranin A; D002864:Chromogranins; D016900:Neurofilament Proteins; D017475:Receptors, Nerve Growth Factor; D009418:S100 Proteins