ALS-Associated KIF5A Mutations Abolish Autoinhibition Resulting in a Toxic Gain of Function [RNA-seq]

Purpose: The goal of this study was to identify gene expression changes in iMNs containing a patient KIF5a mutation compared to an isogenic control. Further, splicing changes were evaluated in the mutant vs WT sample. Methods: RNA samples were extracted and sequenced on an Illumina NovaSeq6000 instrument at the Yale Center for Genome Analysis. The sample sequence quality control check was performed using FastQc. The STAR aligner program was used for read mapping with reference file and HTSeq was used to count the reads for each transcript in strand specific mode. The Differential expression analysis was performed using the DESeq2 package to compare the gene expression profiles between wild type and mutant was performed using the Wald test to generate p-values and Log2 fold changes. The STAR aligned RNA Sequence sample bam files were used to detect differential alternative splicing events with the Multivariate Analysis of Transcript Splicing (MATS) method. Pathway analysis was performed with Metascape Results: With the RNA Sequence pipeline, we analyzed the RNA Sequence from wild-type parental line (Iso Control) and the heterozygous mutant line (KIF5AR1007K). The RNA Sequence analysis of the iMNs revealed 57 genes displaying altered expression. Using the method, Multivariate Analysis of Transcript Splicing (MATS), we identified 1,919 transcripts with altered splicing compared to the isogenic control iMNs. Of these, 1,000 exons showed decreased skipping, while 919 showed increased skipping in KIF5AR1007K lines. Pathway analysis of each of these groups suggests that this group of altered genes, as a whole, represents cytoskeletal and transport defects in the cell, both of which are hallmarks of neurodegenerative disease. mRNA profiles of DIV15 iMNs harboring a KIF5AR1007K mutation and its isogenic control