LINGO-1 Negatively Regulates Oligodendrocyte Differentiation by Blocking the β-integrin Signaling Pathway (I10.002)

Objective: To identify how LINGO-1 (leucine-rich repeat and immunoglobulin domain-containing Nogo receptor-interacting protein-1) and anti-LINGO-1 (BIIB033) affect signaling molecules involved in oligodendrocyte differentiation, myelination and remyelination. Background: LINGO-1 is a negative regulator of oligodendrocyte differentiation, myelination and remyelination, whereas integrin signaling plays an important role in oligodendrocyte survival and differentiation. β1-integrin is known to be required for oligodendrocyte precursor cell (OPC) differentiation. Three separate experiments were performed to determine whether LINGO-1 has a role in downregulating β1-integrin, and if this relationship is affected by anti-LINGO-1. Methods: To assess OPC maturation and myelination, A2B5 + OPCs were cultured in differentiation medium containing neurotrophin-3 and ciliary neurotrophic factor for 3 days. Rat oligodendrocytes and dorsal root ganglion (DRG) neurons were purified and nerve growth factor used in the OPC/DRG co-culture to inhibit basal level myelination. Cells were lysed and Western blotting was performed using antibodies to myelin basic protein (MBP), myelin associated glycoprotein, and actin. In addition, HEK293 cells were transfected with plasmids encoding full length LINGO-1, β1 or α6 integrin. Cells were harvested after 48 hours, lysed, and analyzed by Western blotting using anti-LINGO-1, anti-β1 integrin and anti-α6 integrin antibodies. Finally, RNA was isolated from oligodendrocyte cells and quantitative reverse transcription PCR used to quantify MBP mRNA levels with β-actin used as an internal control. Results: We found that LINGO-1 binds to and down regulates β1-integrin expression. Also, anti-LINGO-1 antibody (BIIB033) enhanced oligodendrocyte differentiation by up-regulating integrin expression. Furthermore, antagonists of the integrin-signaling pathway, including a β1-integrin blocking antibody, are able to block anti-LINGO-1-induced oligodendrocyte differentiation, suggesting that LINGO-1 negatively regulates oligodendrocyte differentiation by down-regulating the β1-integrin signaling pathway. Conclusions: Our data suggest that LINGO-1 and anti-LINGO-1 affect oligodendrocyte differentiation and myelination by regulating the β1-integrin signaling pathway.Study supported by: Biogen. Disclosure: Dr. Mi holds stock and/or stock options in Biogen, which sponsored research in which Dr. Mi was involved as an investigator. Dr. Huang holds stock and/or stock options in Biogen Idec, which sponsored research in which Dr.Huang was involved as an investigator. Dr. Lee holds stock and/or stock options in Biogen, which sponsored research in which Dr. Lee was involved as an investigator. Dr. Shao holds stock and/or stock options in Biogen Idec.