Eur J Anat, 5 (1): 1-9 (2001)

Intermediate filament proteins in developing and adult human dorsal root and sympathetic ganglia

Jose S., Germana G.P., Vazquez M.T., Naves F.J., Esteban I., Vega J.A.

Departamento de Morfologia Celular, Facultad de Medicina, C/ Julían Claveria, s/n, 33006-Oviedo, Spain

ABSTRACT Neuronal maturation in the central nervous system, as well as in some cells deriving from neural crest, is accompanied by a swich in the expression of cytoskeletal intermediate filament proteins. Whether this occurs in humans and the exact timing of this change in human dorsal root and sympathetic ganglia are matters still open to debate. The present study was designed to analyze these issues in human embryos (estimated gestational age -e.g.a.- ranging between 6 and 12 weeks), as well as the possible co-expression of more than one intermediate filament protein in both embryos and adults. A panel of commercially available antibodies against vimentin, glial fibrillary acidic protein and neurofilament proteins was used. Glial fibrillary acidic protein was consistently absent in both developing and adult dorsal root or sympathetic ganglia. Conversely, embryonic neurons, satellite glial cells and Schwann cells displayed vimentin immunoreactivity. The number of vimentin immunoreactive neurons decreased progressively, and it was absent from neurons by 12 weeks e.g.a., while it persisted in satellite glial and Schwann cells. By adulthood, the pattern of distribution was identical. The occurrence of neurofilament proteins in peripheral neurons was a regular feature from early developmental stages to adulthood, and a time-dependent increase in the percentage of neurons containing phosphorylated neurofilaments was observed. The present results demonstrate that developing human dorsal root and sympathetic ganglion neurons co-express vimentin and neurofilaments for a short time, but that the intermediate filaments for mature neurons are neurofilaments. Our findings also show that co-expression or a switch in the expression of intermediate filament proteins do not occur in satellite glial cells or Schwann cells, which normally contain vimentin and not glial fibrillary acidic protein.

Keywords: intermediate filament protein, vimentin, adult, article, cytoskeleton, embryo, human, human tissue, immunohistochemistry, intermediate filament, nerve cell, nervous system development, protein expression, spinal ganglion, sympathetic ganglion