NAD+ Boosts Brain Autophagy Through RNA Splicing to Clear Alzheimer's Proteins

This groundbreaking research reveals how NAD+ supplementation combats neurodegeneration through a previously unknown mechanism linking metabolism, RNA processing, and cellular cleanup systems. The discovery addresses a critical gap in understanding how metabolic restoration translates into improved brain function during aging.

Using cross-species analyses in C. elegans, mice, and human samples, researchers found that NAD+ supplementation corrects hundreds of age- and Alzheimer's-associated RNA splicing errors. Most notably, NAD+ restores balanced expression of EVA1C protein isoforms, which are dramatically reduced in early Alzheimer's disease stages.

The study demonstrates that EVA1C acts as a crucial translator between RNA splicing fidelity and protein homeostasis. Different EVA1C isoforms interact with chaperone proteins BAG1 and HSPA/HSP70, which regulate both autophagy and proteasome systems. NAD+ supplementation strengthens these interactions, creating a cascade: NAD+ restoration → corrected RNA splicing → EVA1C rebalancing → enhanced chaperone networks → improved autophagy of misfolded tau proteins.

Functional experiments confirmed EVA1C's essential role - knocking down this protein completely abolished the memory improvements seen with NAD+ supplementation in tauopathy models. This establishes EVA1C as a critical mediator of NAD+'s neuroprotective effects.

The findings reveal that metabolism and RNA splicing operate as synchronized layers of the same protein quality control network. Age-related NAD+ decline disrupts this coordination, weakening both RNA processing and cellular cleanup systems, predisposing neurons to tau aggregation and degeneration. This work expands autophagy regulation concepts and suggests combined metabolic and autophagy-targeted interventions could reinforce neuronal homeostasis during aging.