RNA G-quadruplexes mediated protein aggregation in neurodegenerative diseases.

RNA G-quadruplexes (rG4s) are stable secondary structures formed by guanine-rich RNA sequences that have emerged as critical regulators of RNA metabolism. The rG4s are widespread in both coding and noncoding RNAs and have been implicated in regulating multiple post-transcriptional processes, including RNA stability, splicing, polyadenylation, nuclear export, localization, and translation. Recent findings reveal that rG4s play pathological roles in neurodegenerative diseases (NDs), including Alzheimer's disease (AD) and Parkinson's disease (PD). The rG4s function in stress granule dynamics, aberrant phase separation, and the nucleation of pathological protein assemblies, which is implicated in protein co-aggregation and pathological protein aggregation in NDs. Here, we provide an integrated synthesis of how rG4s influence protein aggregation through biophysical, cellular, and molecular mechanisms, with particular emphasis on rG4-driven perturbations of phase separation and aggregation pathways. The rG4s relevant disease pathogenesis, biomarker development, and therapeutic interventions in NDs are discussed. Furthermore, we highlight emerging translational opportunities, including the potential of rG4-targeting small molecules such as 5-aminolevulinic acid (5-ALA) and other modulators, which may open new avenues for combating neurodegeneration.