RNA-binding proteins in ALS and FTD: from pathogenic mechanisms to therapeutic insights.

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are devastating neurodegenerative disorders with overlapping clinical, genetic and pathological features. A large body of evidence highlights the critical role of RNA-binding proteins (RBPs) - in particular TAR DNA-binding protein 43 (TDP-43) and Fused in sarcoma (FUS) - in the pathogenesis of these diseases. These RBPs normally regulate various key aspects of RNA metabolism in the nervous system (by assembling into transient biomolecular condensates), but undergo cytoplasmic mislocalization and pathological aggregation in ALS and FTD. Furthermore, emerging evidence suggests that RBP-containing aggregates may propagate through the nervous system in a prion-like manner, driving the progression of these neurodegenerative diseases. In this review, we summarize the genetic and neuropathological findings that establish RBP dysfunction as a central theme in ALS and FTD, and discuss the role of disease-associated RBPs in health and disease. Furthermore, we review emerging evidence regarding the prion-like properties of RBP pathology, and explore the downstream mechanisms that drive neurodegeneration. By unraveling the complex role of RBPs in ALS and FTD, we ultimately aim to provide insights into potential avenues for therapeutic intervention in these incurable disorders.