Pathogenic mechanisms of KIF5A-associated ALS

Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disease characterized by motor neuron degeneration and has been linked to mutations in the KIF5A gene, which encodes the motor protein KIF5A. The ALS-associated KIF5A variants result in exon 27 skipping (KIF5AΔE27), generating a novel C- terminal peptide. This study comprehensively investigates the molecular mechanisms underlying KIF5AΔE27's role in ALS pathogenesis through three specific aims. Aim 1 focuses on determining the gain of function in transgenic mice expressing KIF5AΔE27. Preliminary data demonstrate early neurite aggregates and mild motor deficits in these mice, suggesting age-dependent motor deficits and pathological abnormalities. We also aim to identify age- and disease-dependent molecular pathway alterations in the spinal cord. Aim 2 delves into cargo transport deficits and altered RNA metabolism caused by KIF5AΔE27 in induced pluripotent stem cell-derived motor neurons. Our proteomic analyses have revealed a range of proteins with altered binding to KIF5AΔE27, particularly those associated with mitochondria and RNA granules. Aim 2A focuses on identifying altered cargo transport, while Aim 2B explores mRNA metabolism defects by profiling mRNA transcripts and splicing patterns. Aim 3 investigates the molecular determinants and toxicity of KIF5AΔE27 aggregates. We aim to elucidate the role of active transport processes in KIF5AΔE27 aggregation in Aim 3A, and in Aim 3B, we will explore whether these aggregates contribute to neurotoxicity while investigating their regulation by altered interacting proteins. These multidisciplinary approaches offer a comprehensive examination of KIF5AΔE27 in ALS, potentially yielding critical insights into disease mechanisms and innovative therapeutic strategies.