Reduced PHOX2B stability causes axonal growth impairment in motor neurons with TARDBP mutations

• Published in: Stem cell reports 2021-06, Vol.16 (6), p.1527-1541
• Main Authors: Mitsuzawa, Shio, Suzuki, Naoki, Akiyama, Tetsuya, Ishikawa, Mitsuru, Sone, Takefumi, Kawada, Jiro, Funayama, Ryo, Shirota, Matsuyuki, Mitsuhashi, Hiroaki, Morimoto, Satoru, Ikeda, Kensuke, Shijo, Tomomi, Ohno, Akiyuki, Nakamura, Naoko, Ono, Hiroya, Ono, Risako, Osana, Shion, Nakagawa, Tadashi, Nishiyama, Ayumi, Izumi, Rumiko, Kaneda, Shohei, Ikeuchi, Yoshiho, Nakayama, Keiko, Fujii, Teruo, Warita, Hitoshi, Okano, Hideyuki, Aoki, Masashi
• Format: Article
• Language: English
• Subjects: amyotrophic lateral sclerosis (ALS); Amyotrophic Lateral Sclerosis - genetics; Amyotrophic Lateral Sclerosis - metabolism; Animals; Axons - metabolism; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Gene Expression Regulation; Gene Knockdown Techniques - methods; Homeodomain Proteins - genetics; Homeodomain Proteins - metabolism; human-induced pluripotent stem cell (hiPSC)-derived motor neurons; Humans; Induced Pluripotent Stem Cells - metabolism; Motor Neurons - metabolism; Mutation; neurite length; Phenotype; TAR-DNA binding protein (TARDBP); Transcription Factors - genetics; Transcription Factors - metabolism; Transcriptome; Zebrafish - metabolism
• ISSN: 2213-6711; 2213-6711
• DOI: 10.1016/j.stemcr.2021.04.021

Amyotrophic lateral sclerosis (ALS) is an adult-onset incurable motor neuron (MN) disease. The reasons for selective MN vulnerability in ALS are unknown. Axonal pathology is among the earliest signs of ALS. We searched for novel modulatory genes in human MN axon shortening affected by TARDBP mutations. In transcriptome analysis of RNA present in the axon compartment of human-derived induced pluripotent stem cell (iPSC)-derived MNs, PHOX2B (paired-like homeobox protein 2B) showed lower expression in TARDBP mutant axons, which was consistent with axon qPCR and in situ hybridization. PHOX2B mRNA stability was reduced in TARDBP mutant MNs. Furthermore, PHOX2B knockdown reduced neurite length in human MNs. Finally, phox2b knockdown in zebrafish induced short spinal axons and impaired escape response. PHOX2B is known to be highly express in other types of neurons maintained after ALS progression. Collectively, TARDBP mutations induced loss of axonal resilience, which is an important ALS-related phenotype mediated by PHOX2B downregulation. [Display omitted] •Human iPSCs were established from a familial ALS with the TARDBP p.G376D mutation•PHOX2B mRNA was identified to be decreased in TARDBP mutant MNs by RNA sequencing•PHOX2B mRNA bind to TDP-43 and its stability was reduced in TARDBP mutant MNs•PHOX2B knockdown reduced neurite length and impaired motor functions in vivo/vitro A novel modulatory gene PHOX2B decreased in human iPSC-derived MNs with TARDBP mutations and PHOX2B knockdown reduced neurite length and impaired motor functions in vivo and vitro. PHOX2B is known that highly express in other type of neurons maintained after the progression of ALS. Collectively, TARDBP mutations induced loss of axonal resilience, an important ALS-related phenotype, is mediated by PHOX2B downregulation.