CRISPR genome editing based isogenic induced pluripotent stem cell system for schizophrenia disease modeling
János M. Réthelyi1, 2, 1, Edit Hathy1, 2, Hella Gyergyák3, Tamás Arányi3, Ágota Apáti3, Dávid Szüts3
Background: Schizophrenia (SCZ) is a severe neuropsychiatric disorder of complex etiology. De novo mutations (DNMs) represent a recently described source of genetic variation in the background of SCZ. In most cases their biological significance remains unclear. The aim of this study was to investigate the biological significance of DNMs in SCZ by combining induced pluripotent stem cell (IPSC) based disease modeling and CRISPR based genome editing. Methods: To this end we selected a SCZ case-parent trio, where the affected patient carries a potentially disease causing DNM. Based on exome sequencing studies we chose a patient harboring a zinc finger MYND domain-containing protein 11 (ZMYND11) 1495C>T nonsense DNM resulting in a R399X stop codon. ZMYND11 encodes a chromatin reader protein associated with CNS function. First we introduced monoallelic or biallelic frameshift mutations into a control wild type IPSC line using CRISPR non-homologous end joining. Next IPSC lines were generated from each member of the case-parent trio. The investigated ZMYND11 mutation was corrected using CRISPR homology-directed repair in the affected IPSC line. These isogenic IPSC lines were taken forward to neuronal differentiation experiments, in which neuronal progenitor cells (NPCs) and mature neurons were differentiated. Results: In ongoing experiments we are investigating morphological, functional and molecular differences in our isogenic system to establish the biological significance of the investigated mutation. RNASeq analyses showed massive upregulation of neuronal differentiation genes in the mutant cell lines, and downregulation of cell adhesion genes. Conclusions: This approach can shed light on the molecular disease pathways underlying schizophrenia. Keywords: schizophrenia, disease modeling, induced pluripotent stem cells, genome editing, CRISPR, isogenic system Funding: This study is funded by the Richter Gedeon Pharmaceuticals Téma Pályázat Grant to DSz and the National Brain Research Program (Grant NAP-B KTIA_NAP_13-2014-0011 to JR). References: Kálmán S, Hathy E, Réthelyi JM: A Dishful of a Troubled Mind: Induced Pluripotent Stem Cells in Psychiatric Research. Stem Cells International, vol. 2016, Article ID 7909176, 21 pages, 2016.