Astrocytes produce CNTF during the remyelination phase of viral-induced spinal cord demyelination to stimulate FGF-2 production

Abstract

Multiple sclerosis is characterized by multiple lesions with selective loss of myelin and oligodendrocytes, leading to deficits of sensation and movement, as well as cognitive disabilities. Consequently, a major research endeavor is to identify strategies to enhance oligodendrocyte regeneration and remyelination. FGF-2 is a potent mitogen for OPCs, and it is induced in astrocytes in animal models of demyelinating diseases in conjunction with successful remyelination. However, the factors responsible for inducing FGF-2 after demyelination in astrocytes are unknown. Here we show that CNTF mRNA and protein increase coincident with spinal cord remyelination in mice recovering from MHV-induced demyelination. We identify CNTF within astrocytes surrounding and within remyelinating lesions, and show that CNTF increases FGF-2 ligand and receptor mRNAs in spinal cord after direct application. Furthermore, we show that CNTF increases FGF-2 mRNA approximately 2.5-fold in cultured mouse spinal cord astrocytes. Altogether, these results strongly implicate CNTF as an important cytokine in demyelinating disease and as an upstream regulator of FGF-2 production in astrocytes during early remyelination.