Morgan, M. Louise; (1993) Schwann cell phenotype during peripheral nerve development and during myelination in vitro. Doctoral thesis (Ph.D), UCL (University College London).

Text Schwann_cell_phenotype_during_.pdf Download (10MB)

Abstract

The appearance of a variety of Schwann cell associated molecules has been followed during development of rat sciatic nerve. Cell surface antigens laminin, N-CAM, low affinity NGF-R, sulphatide, GAL-C, A5E3, LI and intracellular antigens vimentin, S100, GFAP and Po were examined in cells dissociated from sciatic nerves of rats aged between embryonic day 14 and adult. Changes in phenotype as early Schwann cells develop into myelin forming and non-myelin forming Schwann cells are described. Axonal control of Schwann cell phenotype was explored using an in vitro system. It is shown that the axon dependent expression of myelin proteins can be mimicked in vitro by drugs that elevate Schwann cell intracellular cAMP levels. In defined medium, the myelin specific protein Po is expressed by Schwann cells in the presence of cAMP elevating agents. Using in situ hybridisation and northern blots, the changes in levels of Po protein are shown to be the result of increased mRNA levels. The full myelin phenotype is displayed by some of these cells, with new expression of surface lipids sulphatide and GAL-C and loss of the low affinity NGF-R accompanying Po induction. Expression of the myelin phenotype is shown to occur only in the absence of cell division. Growth factors modulate the response of Schwann cells to cAMP elevation. When acidic FGF, basic FGF, GGF, PDGF or serum are present in the culture medium, cAMP elevation is followed by Schwann cell division and little or no Po elevation. On the other hand, elevation of sulphatide is less affected by the presence of growth factors since the rapid division is accompanied by a large induction in the levels of sulphatide. One of the effects of axonal signals could be to elevate Schwann cell cAMP levels, causing sulphatide expression and rapid division during embryonic development and, later, induction of myelin in non dividing cells.

Download activity - last month

Export as JSONXMLCSV

Download activity - last 12 months

Export as JSONCSVXML

Downloads by country - last 12 months

Export as XMLCSVJSON

Archive Staff Only

View Item