Pathologic TDP‐43 downregulates myelin gene expression in the monkey brain

Growing evidence indicates that non‐neuronal oligodendrocyte plays an important role in Amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases. In patient's brain, the impaired myelin structure is a pathological feature with the observation of TDP‐43 in cytoplasm of oligodendrocyte. However, the mechanism underlying the gain of function by TDP‐43 in oligodendrocytes, which are vital for the axonal integrity, remains unclear. Recently, we found that the primate‐specific cleavage of truncated TDP‐43 fragments occurred in cytoplasm of monkey neural cells. This finding opened up the avenue to investigate the myelin integrity affected by pathogenic TDP‐43 in oligodendrocytes. In current study, we demonstrated that the truncated TDP‐35 in oligodendrocytes specifically, could lead to the dysfunctional demyelination in corpus callosum of monkey. As a consequence of the interaction of myelin regulatory factor with the accumulated TDP‐35 in cytoplasm, the downstream myelin‐associated genes expression was downregulated at the transcriptional level. Our study aims to investigate the potential effect on myelin structure injury, affected by the truncated TDP‐43 in oligodendrocyte, which provided the additional clues on the gain of function during the progressive pathogenesis and symptoms in TDP‐43 related diseases. A proposed model of thedemyelination by pathological TDP‐43 in oligodendrocyte. The accumulation of truncated TDP‐43 inoligodendrocyte, could interact with MyRF in the cytoplasm, preventing itsnuclear localization and affecting the expression of myelin‐associated genes, therefore led to the dysfunctional demyelination in corpuscallosum.