Project Grant F31NS147796

NUCLEAR-CYTOSKELETAL COUPLING THROUGH THE GIANT KASH PROTEIN ANC-1 MAINTAINS NEURONAL MECHANICAL INTEGRITY DURING AGING - NEURODEGENERATIVE DISEASES AFFECT 50 MILLION PEOPLE WORLDWIDE WITH DEVASTATING PERSONAL AND SOCIETAL CONSEQUENCES. DESPITE EXTENSIVE RESEARCH EFFORTS, STRATEGIES TARGETING PROTEIN AGGREGATION HAVE SHOWN LIMITED EFFICACY, HIGHLIGHTING A CRITICAL GAP IN OUR UNDERSTANDING OF FUNDAMENTAL NEURODEGENERATION MECHANISMS. MY PRELIMINARY FINDINGS SUGGEST THAT NEURONS MAINTAIN STRUCTURAL INTEGRITY THROUGH MECHANICAL SCAFFOLDING PROVIDED BY GIANT KLARSICHT/ANC- 1/SYNE HOMOLOGY (KASH) PROTEINS, WHICH CONNECT THE ENDOPLASMIC RETICULUM AND NUCLEAR ENVELOPE VIA THEIR C-TERMINUS WHILE LINKING TO THE MICROTUBULE AND ACTIN CYTOSKELETONS THROUGH THEIR ACTIN-BINDING AND KINESIN-BINDING DOMAINS. USING GENETICALLY ENCODED MULTIMERIC NANOPARTICLE (GEM)-BASED NANORHEOLOGY IN CAENORHABDITIS ELEGANS PVD NEURONS, I DEMONSTRATED THAT ANC-1, AN ORTHOLOG OF THE HUMAN GIANT KASH PROTEIN NESPRIN-1, IS CRUCIAL FOR MAINTAINING NEURONAL MECHANICAL STABILITY. LOSS OF ANC-1 LEADS TO ACCELERATED AGING, EVIDENT IN A 42% REDUCTION IN MOBILITY, A 35% DECREASE IN LIFESPAN, AND PROGRESSIVELY WORSENING DENDRITIC DEFECTS. THIS RESEARCH CARRIES SIGNIFICANT CLINICAL RELEVANCE AS MUTATIONS IN THE SYNE1 GENE THAT ENCODES NESPRIN-1 ARE IMPLICATED IN AMYOTROPHIC LATERAL SCLEROSIS AND SPINOCEREBELLAR ATAXIA. THE CENTRAL HYPOTHESIS OF THIS WORK IS THAT ANC-1 LOSS LEADS TO NEURODEGENERATION BY DISRUPTING THE CRITICAL SCAFFOLDING BETWEEN THE NUCLEUS, ENDOPLASMIC RETICULUM, AND CYTOSKELETON, INDUCING MECHANICAL INSTABILITY AND SUBSEQUENT NEURONAL DETERIORATION. TO INVESTIGATE THIS, MY RESEARCH ADDRESSES THREE SPECIFIC AIMS: (1) DEFINE HOW AGING NEURONS MAINTAIN INTERNAL STRUCTURE AND MECHANICAL STABILITY THROUGH GIANT KASH PROTEIN SCAFFOLDING; (2) DETERMINE HOW DISEASE- ASSOCIATED MUTATIONS IN THE CONSERVED ACTIN-BINDING DOMAIN OF GIANT KASH PROTEINS ALTER ACTIN INTERACTIONS AND NEURONAL MECHANICAL PROPERTIES; AND (3) INVESTIGATE THE TEMPORAL PROGRESSION OF NEURODEGENERATION AFTER GIANT KASH PROTEIN LOSS AND IDENTIFY WINDOWS WHERE INTERVENTION IS VIABLE. COMPLETION OF THIS RESEARCH WILL FUNDAMENTALLY SHIFT OUR UNDERSTANDING OF NEURODEGENERATION BY ESTABLISHING MECHANICAL INSTABILITY AS A KEY DRIVER OF NEURONAL DECLINE, IDENTIFYING MECHANICAL SIGNATURES PREDICTIVE OF NEURODEGENERATION, AND DEVELOPING A PARADIGM THAT PRIORITIZES MECHANICAL STABILITY RESTORATION OVER TARGETING PROTEIN AGGREGATION.