Nerve Growth Factor neutralization promotes oligodendrogenesis by increasing miR-219a-5p levels

Alterations of the crosstalk between the nervous and immune systems may underlie the inflammatory and neurodegenerative changes characterizing Multiple Sclerosis (MS). Among the molecules that actively interconnect these two systems is the Nerve Growth Factor (NGF), involved in both regulating inflammation and in brain homeostasis. Additionally, NGF is known to modulate oligodendrogenesis and reduce myelination, further suggesting an involvement of NGF in MS ethiology. In this study, we find that NGF regulates oligodendrogenesis by modulating the levels of miR-219a-5p, a well-known positive regulator of oligodendrocyte (OL) differentiation. We utilized a transgenic NGF-deprivation mouse model, AD11, in which postnatal expression of an anti-NGF antibody leads to NGF neutralization and progressive neurodegeneration. Notably, we find that these mice also display increased myelination. A microRNA profiling of AD11 brain samples (hippocampus) by Agilent microarray analysis revealed that NGF deprivation leads to an increase of miR-219a-5p levels and a downregulation of its predicted targets, compared to AD11-VH control mice. The AD11-VH controls are transgenic mice where only the heavy chain of the transgenic antibody is expressed, while in AD11 mice express the whole functional antibody (heavy + light chain) A transcriptomic profile of microRNA genes was obtained from the brain hippocampus of transgenic anti-NGF AD11 mice and control mice, at 1 month of age. A total of n=8 samples were analyzed by Agilent microarray: n=4 AD11 samples and n=4 control samples.