Kristjan Jessen

Biography

We are interested in Schwann cells, the glial cells of peripheral nerves. These cells provide signals, which during development are required for neuronal survival, and which are essential for the integrity of peripheral nerves in the adult. They also make myelin-sheaths around axons that are needed for the normal conduction of nerve impulses. In damaged nerves, Schwann cells guide re-growing axons and make nerve repair possible.
Schwann cells show a striking ability to de-differentiate. This happens for instance when nerves are injured and it is phenotypic plasticity that generates an environment that supports axon growth and nerve regeneration. But Schwann cell de-differentiation and de-myelination is also a major problem in the common inherited and acquired peripheral neuropathies.
The work of the laboratory addresses a group of interlocking issues in Schwann cell biology.
(i) Early Schwann cell development and the biology of the Schwann Cell Precursor
(ii) Control of myelination,
(iii) The response of Schwann cells to injury and genetic disease, including the process of de-myelination and control of axon re-growth and nerve repair.

To learn about these events, we study molecular signalling in neural crest cells and between neurones and glia, examine how transcription factors control differentiation programmes and analyse intracellular signalling cascades that regulate survival, proliferation, myelination and demyelination. We use cells from rats, and normal and transgenic and knockout mice, and a variety of molecular, biochemical, cell biological and cell culture techniques.

Keywords: Axon regeneration, Demyelination, Development, Differentiation, Myelin, Regeneration, Remyelination, Repair, Wallerian degeneration

Conditions: Charcot-Marie-Tooth disease, Chronic inflammatory demyelinating polyneuropathy, Guillain-Barré syndrome, Gliomas, Neuropathy, Neurofibromatosis

Methods: Cell culture, Cell transplantation, Confocal microscopy, Electron Microscopy, fluorescence microscopy techniques, Gene expression profiling – tissue level, Genetic manipulation (including knockout/knockin) , Image analysis, Immunohistochemistry, Neuroanatomical approaches , Transgenic mice, Viral vectors