CHMP2B promotes CHMP7 mediated nuclear pore complex injury in sporadic ALS.

Abstract

Alterations to the composition and function of neuronal nuclear pore complexes (NPCs) have been documented in multiple neurodegenerative diseases including Amyotrophic Lateral Sclerosis (ALS). Moreover, recent work has suggested that injury to the NPC can at least in part contribute to TDP-43 loss of function and mislocalization, a pathological hallmark of ALS and related neurodegenerative diseases. Collectively, these studies highlight a role for disruptions in NPC homeostasis and surveillance as a significant pathophysiologic event in neurodegeneration. The ESCRT-III nuclear surveillance pathway plays a critical role in the surveillance and maintenance of NPCs and the surrounding nuclear environment. Importantly, pathologic alterations to this pathway and its protein constituents have been implicated in neurodegenerative diseases such as ALS. However, the mechanism by which this pathway contributes to disease associated alterations in the NPC remains unknown. Here we use an induced pluripotent stem cell (iPSC) derived neuron (iPSN) model of sALS to demonstrate that CHMP7/ESCRT-III nuclear maintenance/surveillance is overactivated in sALS neurons. This overactivation is dependent upon the ESCRT-III protein CHMP2B and sustained CHMP2B dependent "activation" is sufficient to contribute to pathologic CHMP7 nuclear accumulation and POM121 reduction. Importantly, partial knockdown of CHMP2B was sufficient to alleviate NPC injury and downstream TDP-43 dysfunction in sALS neurons thereby highlighting CHMP2B as a potential therapeutic target in disease.