Impaired neuronal activity and differential gene expression in STXBP1 encephalopathy patient iPSC-derived GABAergic neurons

Eisuke Ichise, Tomohiro Chiyonobu, Mitsuru Ishikawa, Yasuyoshi Tanaka, Mami Shibata, Takenori Tozawa, Yoshihiro Taura, Satoshi Yamashita, Michiko Yoshida, Masafumi Morimoto, Norimichi Higurashi, Toshiyuki Yamamoto, Hideyuki Okano, Shinichi Hirose

Research output: Contribution to journalArticlepeer-review

Abstract

Syntaxin-binding protein 1 (STXBP1; also called MUNC18-1), encoded by STXBP1, is an essential component of the molecular machinery that controls synaptic vesicle docking and fusion. De novo pathogenic variants of STXBP1 cause a complex set of neurological disturbances, namely STXBP1 encephalopathy (STXBP1-E) that includes epilepsy, neurodevelopmental disorders and neurodegeneration. Several animal studies have suggested the contribution of GABAergic dysfunction in STXBP1-E pathogenesis. However, the pathophysiological changes in GABAergic neurons of these patients are still poorly understood. Here, we exclusively generated GABAergic neurons from STXBP1-E patient-derived induced pluripotent stem cells (iPSCs) by transient expression of the transcription factors ASCL1 and DLX2. We also generated CRISPR/Cas9-edited isogenic iPSC-derived GABAergic (iPSC GABA) neurons as controls. We demonstrated that the reduction in STXBP1 protein levels in patient-derived iPSC GABA neurons was slight (approximately 20%) compared to the control neurons, despite a 50% reduction in STXBP1 mRNA levels. Using a microelectrode array-based assay, we found that patient-derived iPSC GABA neurons exhibited dysfunctional maturation with reduced numbers of spontaneous spikes and bursts. These findings reinforce the idea that GABAergic dysfunction is a crucial contributor to STXBP1-E pathogenesis. Moreover, gene expression analysis revealed specific dysregulation of genes previously implicated in epilepsy, neurodevelopment and neurodegeneration in patient-derived iPSC GABA neurons, namely KCNH1, KCNH5, CNN3, RASGRF1, SEMA3A, SIAH3 and INPP5F. Thus, our study provides new insights for understanding the biological processes underlying the widespread neuropathological features of STXBP1-E.

Original languageEnglish
Pages (from-to)1337-1348
Number of pages12
JournalHuman molecular genetics
Volume30
Issue number14
DOIs
Publication statusPublished - 2021 Jul 15

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Genetics(clinical)

Fingerprint

Dive into the research topics of 'Impaired neuronal activity and differential gene expression in STXBP1 encephalopathy patient iPSC-derived GABAergic neurons'. Together they form a unique fingerprint.

Cite this