## Abstract Insulin‐like growth factor 1 (IGF‐1) is a growth and survival factor for oligodendrocyte lineage cells and promotes myelination. We demonstrate that IGF‐binding protein 6 (IGFBP‐6) is expressed and localized to the Golgi complex in rat oligodendrocyte precursor (O2A) cells. IGFBP‐6 mRNA
Insulin-like growth factor binding proteins-1 and -2 differentially inhibit rat oligodendrocyte precursor cell survival and differentiation in vitro
✍ Scribed by Nicole M. Kühl; Jacques De Keyser; Hans De Vries; Dick Hoekstra
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 310 KB
- Volume
- 69
- Category
- Article
- ISSN
- 0360-4012
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✦ Synopsis
Insulin-like growth factor-1 (IGF-1) is a growth and survival factor for oligodendrocyte lineage cells and induces myelination. Its actions are modulated by IGF binding proteins (IGFBPs) that are present in the extracellular fluids or on the cell surface. Additionally, IGFBPs are also known to exert actions that are independent of IGF-1. We studied whether IGF-binding proteins (IGFBPs)-1 and -2 modulate rat oligodendrocyte precursor (O2A) cell survival and differentiation in vitro both in the absence and presence of exogenously added IGF-1. The data reveal that IGFBP-1 and -2 reduced O2A cell survival in the absence and presence of exogenously added IGF-1. The effects of IGFBP-1 on cell survival in the presence of exogenously added IGF-1 were IGF-1-dependent, whereas IGFBP-2 displayed both IGF-1-dependent and IGF-1-independent effects. Furthermore, IGFBP-1 and -2 inhibited O2A cell differentiation in the presence of IGF-1 as reflected by decreased expression levels of two myelin proteins, CNPase (2',3'-cyclic nucleotide 3'-phosphohydrolase) and MAG (myelin associated glycoprotein). Analysis of medium samples revealed that O2A cells do not secrete proteases that degrade these IGFBPs. Taken together the data show that IGFBP-1 and -2 are negative effectors of oligodendrocyte survival and differentiation. Accordingly, the role of IGFBPs should be explicitly taken into account when investigating IGF-1 effects on oligodendrocytes, especially in the context of therapeutic purposes.
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