SCIP/Oct‐6, Krox‐20 and desert hedgehog mRNA expression during CNS remyelination by transplanted olfactory ensheathing cells

Abstract

Olfactory ensheathing cells (OECs) are able to generate myelin sheaths following transplantation into areas of CNS demyelination that are remarkably similar to those made by Schwann cells despite their separate developmental origin. The transcriptional control of Schwann cell myelination has been well documented, but whether the same transcription factors are also expressed when OECs assume a myelinating phenotype is not known. We have addressed this question by using a transplantation approach to generate myelinating OECs and examined the expression of SCIP/Oct‐6 and Krox‐20 mRNA by in situ hybridization. We also examined the expression of desert hedgehog (Dhh), a Schwann cell derived signalling molecule responsible for regulating the development of the connective tissue elements in peripheral nerve. Our results indicate that both Krox‐20 and Dhh mRNA are strongly expressed by transplanted OECs, with SCIP mRNA present at much lower levels. The expression of Krox‐20 relative to the expression of P0 mRNA by the transplanted OECs is consistent with it playing a similar role in OEC myelination to that in Schwann cell myelination, while the expression of Dhh suggests a possible mechanism for the diverse morphologies that OECs adopt following transplantation into the damaged CNS.