title: Nestin-immunoreactive cells in rat pituitary are neither hormonal nor typical folliculo-stellate cells.
abstract: Nestin is an intermediate filament protein that has originally been identified as a marker of neuroepithelial stem/progenitor cells. The present study explored whether nestin immunoreactivity (nestin-ir) is present in the rat pituitary and in which cell type(s). Nestin-ir was observed in scattered cells in the anterior, intermediate, and neural lobes. Nestin-ir cells were predominantly of stellate shape and were more numerous in immature than in adult animals. Nestin-ir did not colocalize with any pituitary hormone, and did not colocalize or only very sporadically with the folliculo-stellate cell marker S100. In the intermediate lobe, nestin-ir cells contained glial fibrillary acidic protein in an age-dependent manner. Nestin-ir cells were closely associated with endothelial and fibronectin-ir cells, but did mostly not coincide. Nestin-ir was not found in alpha-smooth muscle actin-ir myofibroblasts or in microglial cells. Regardless of age, nestin-ir was detected in some unidentifiable cells that border the pituitary cleft. Nestin-ir remained present in pituitary cultured as three-dimensional aggregates. Treatment with basic fibroblast growth factor or leukemia inhibitory factor increased the number of nestin-ir cells. Starting from anterior lobe cell monolayer cultures, nestin-ir cells could be selected and propagated to a virtually pure population. These nestin-ir cells displayed remarkable motility and proliferative activity, and did not express hormones, glial fibrillary acidic protein, or S100, but contained vimentin-, fibronectin-, and alpha-smooth muscle actin-ir. In conclusion, nestin-ir is present in the pituitary in cells that are neither hormonal nor typical folliculo-stellate. The expression pattern depends on age and lobe examined. Pericapillar localization suggests a pericyte phenotype for some of them. Whether the heterogeneous nestin-ir population also contains pituitary progenitor cells remains to be explored.
authors.affiliation: Laboratory of Cell Pharmacology, Department of Molecular Cell Biology, University of Leuven, Campus Gasthuisberg, B-3000 Leuven, Belgium.
authors.forename: Olga
authors.initials: O
authors.lastname: Krylyshkina
authors.forename: Jianghai
authors.initials: J
authors.lastname: Chen
authors.forename: Liese
authors.initials: L
authors.lastname: Mebis
authors.forename: Carl
authors.initials: C
authors.lastname: Denef
authors.forename: Hugo
authors.initials: H
authors.lastname: Vankelecom
mesh_terms: D000199:Actins / Q000032:analysis; D000375:Aging; D000818:Animals; D002478:Cells, Cultured; D005260:Female; D005353:Fibronectins / Q000032:analysis; D015870:Gene Expression; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006728:Hormones / Q000032:analysis*; D007150:Immunohistochemistry; D007381:Intermediate Filament Proteins / Q000032:analysis* / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000235:genetics; D064231:Nestin; D010902:Pituitary Gland / Q000737:chemistry* / Q000166:cytology*; D010903:Pituitary Gland, Anterior / Q000737:chemistry / Q000166:cytology; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D009418:S100 Proteins / Q000032:analysis; D046509:Tissue Culture Techniques; D014746:Vimentin / Q000032:analysis
chemical_list: D000199:Actins; D005353:Fibronectins; D005904:Glial Fibrillary Acidic Protein; D006728:Hormones; D007381:Intermediate Filament Proteins; D009419:Nerve Tissue Proteins; C577486:Nes protein, rat; D064231:Nestin; D009418:S100 Proteins; D014746:Vimentin