Contributions
Abstract: 237
Type: Oral
Abstract Category: Pathology and pathogenesis of MS - 20 Repairing mechanisms
Multiple Sclerosis (MS) is a demyelinating disease of the central nervous system (CNS). Major characteristic is a multifocal destruction of the insulating myelin sheath around the axons due to an inflammatory process. These demyelinated lesions may be remyelinated by oligodendroglial progenitor cells (OPCs). However, remyelination declines with disease progression and available MS therapies do not enhance this repair process. As it was repeatedly reported that migration as well as differentiation of OPCs are impaired in MS lesions, understanding the modulation of these characteristics is a prerequisite for identifying new targets to improve remyelination. Myelination of the peripheral nervous system is regulated by calcineurin/NFAT signalling. Nuclear factor of activated T cells (NFAT) is a family of transcription factors with five members. Four of them, NFATc1-4, are regulated by the Ca2+/calmodulin-dependent phosphatase calcineurin.
In our study we demonstrate that calcineurin regulated NFATc family members are expressed in murine and human oligodendroglial cells on mRNA and protein level. For functional analysis of NFATc inhibition in oligodendrocytes we used the small molecule VIVIT that specifically inhibits NFATc/calcineurin interaction. VIVIT treatment of primary murine OPCs resulted in an impaired differentiation and a reduced migration capacity. To investigate the effect of VIVIT on myelination we administered VIVIT to murine organotypic cerebellar slice cultures (OCSCs) at a time point when axons start to migrate into the cerebellum. Analysis of the ratio between neurofilament as an axonal marker and MBP expression revealed a reduced myelination in VIVIT treated OCSCs. Exposure of human iPS-derived oligodendrocytes (hiOL) to VIVIT led to a decreased differentiation, whereas migration capacity was increased. To further corroborate our in vitro and ex vivo data we investigated NFATc expression in MS lesions. NFATc1-4 were expressed in MS lesions, but only NFATc3 and NFATc4 were detectable in oligodendrocytes. Additionally, NFATc4 was markedly downregulated in a subset of oligodendrocytes in active MS lesions.
In summary, our data suggest that the NFATc transcription factor family is important for oligodendroglial differentiation and that reduced NFATc4 expression in MS may contribute to an impaired oligodendroglial differentiation in MS lesions. Therefore, modulation of NFATc's might be a therapeutical target to enhance remyelination in MS patients.
Disclosure:
M.E. and T.K. have a pending patent application for the oligodendroglial differentiation protocol.
All other authors: Nothing to disclose.
Abstract: 237
Type: Oral
Abstract Category: Pathology and pathogenesis of MS - 20 Repairing mechanisms
Multiple Sclerosis (MS) is a demyelinating disease of the central nervous system (CNS). Major characteristic is a multifocal destruction of the insulating myelin sheath around the axons due to an inflammatory process. These demyelinated lesions may be remyelinated by oligodendroglial progenitor cells (OPCs). However, remyelination declines with disease progression and available MS therapies do not enhance this repair process. As it was repeatedly reported that migration as well as differentiation of OPCs are impaired in MS lesions, understanding the modulation of these characteristics is a prerequisite for identifying new targets to improve remyelination. Myelination of the peripheral nervous system is regulated by calcineurin/NFAT signalling. Nuclear factor of activated T cells (NFAT) is a family of transcription factors with five members. Four of them, NFATc1-4, are regulated by the Ca2+/calmodulin-dependent phosphatase calcineurin.
In our study we demonstrate that calcineurin regulated NFATc family members are expressed in murine and human oligodendroglial cells on mRNA and protein level. For functional analysis of NFATc inhibition in oligodendrocytes we used the small molecule VIVIT that specifically inhibits NFATc/calcineurin interaction. VIVIT treatment of primary murine OPCs resulted in an impaired differentiation and a reduced migration capacity. To investigate the effect of VIVIT on myelination we administered VIVIT to murine organotypic cerebellar slice cultures (OCSCs) at a time point when axons start to migrate into the cerebellum. Analysis of the ratio between neurofilament as an axonal marker and MBP expression revealed a reduced myelination in VIVIT treated OCSCs. Exposure of human iPS-derived oligodendrocytes (hiOL) to VIVIT led to a decreased differentiation, whereas migration capacity was increased. To further corroborate our in vitro and ex vivo data we investigated NFATc expression in MS lesions. NFATc1-4 were expressed in MS lesions, but only NFATc3 and NFATc4 were detectable in oligodendrocytes. Additionally, NFATc4 was markedly downregulated in a subset of oligodendrocytes in active MS lesions.
In summary, our data suggest that the NFATc transcription factor family is important for oligodendroglial differentiation and that reduced NFATc4 expression in MS may contribute to an impaired oligodendroglial differentiation in MS lesions. Therefore, modulation of NFATc's might be a therapeutical target to enhance remyelination in MS patients.
Disclosure:
M.E. and T.K. have a pending patent application for the oligodendroglial differentiation protocol.
All other authors: Nothing to disclose.