Serotonin-specific neurons differentiated from human iPSCs form distinct subtypes with synaptic protein assembly.

Human induced pluripotent stem cells (hiPSCs) have revolutionized the generation of experimental disease models, but the development of protocols for the differentiation of functionally active neuronal subtypes with defined specification is still in its infancy. While dysfunction of the brain serotonin (5-HT) system has been implicated in the etiology of various neuropsychiatric disorders, investigation of functional human 5-HT specific neurons in vitro has been restricted by technical limitations. We describe an efficient generation of functionally active neurons from hiPSCs displaying 5-HT specification by modification of a previously reported protocol. Furthermore, 5-HT specific neurons were characterized using high-end fluorescence imaging including super-resolution microscopy in combination with electrophysiological techniques. Differentiated hiPSCs synthesize 5-HT, express specific markers, such as tryptophan hydroxylase 2 and 5-HT transporter, and exhibit an electrophysiological signature characteristic of serotonergic neurons, with spontaneous rhythmic activities, broad action potentials and large afterhyperpolarization potentials. 5-HT specific neurons form synapses reflected by the expression of pre- and postsynaptic proteins, such as Bassoon and Homer. The distribution pattern of Bassoon, a marker of the active zone along the soma and extensions of neurons, indicates functionality via volume transmission. Among the high percentage of 5-HT specific neurons (~ 42%), a subpopulation of CDH13 + cells presumably designates dorsal raphe neurons. hiPSC-derived 5-HT specific neuronal cell cultures reflect the heterogeneous nature of dorsal and median raphe nuclei and may facilitate examining the association of serotonergic neuron subpopulations with neuropsychiatric disorders.

Generation of a ST3GAL3 null mutant induced pluripotent stem cell (iPSC) line (UKWMPi002-A-3) by CRISPR/Cas9 genome editing.

Fibroblasts isolated from a skin biopsy of a healthy individual were infected with Sendai virus containing the Yamanaka factors to produce transgene-free human induced pluripotent stem cells (iPSCs). CRISPR/Cas9 was used to generate an isogenic cell line carrying an inactivation of ST3GAL3, a risk gene associated with neurodevelopmental and psychiatric disorders. This ST3GAL3 null mutant (ST3GAL3-/-) iPSC line, which displays the expression of pluripotency-associated markers, the ability to differentiate into cells of the three germ layers in vitro, and a normal karyotype, is a powerful tool to investigate the impact of deficient sialylation of glycoproteins in neural development and plasticity.

Generation of multiple human iPSC lines from peripheral blood mononuclear cells of two SLC2A3 deletion and two SLC2A3 duplication carriers.

Copy number variants of SLC2A3, which encodes the glucose transporter GLUT3, are associated with several neuropsychiatric and cardiac diseases. Here, we report the successful reprogramming of peripheral blood mononuclear cells from two SLC2A3 duplication and two SLC2A3 deletion carriers and subsequent generation of two transgene-free iPSC clones per donor by Sendai viral transduction. All eight clones represent bona fide hiPSCs with high expression of pluripotency genes, ability to differentiate into cells of all three germ layers and normal karyotype. The generated cell lines will be helpful to enlighten the role of glucometabolic alterations in pathophysiological processes shared across organ boundaries.

Generation of induced pluripotent stem cell (iPSC) lines carrying a heterozygous (UKWMPi002-A-1) and null mutant knockout (UKWMPi002-A-2) of Cadherin 13 associated with neurodevelopmental disorders using CRISPR/Cas9.

Fibroblasts isolated from a skin biopsy of a healthy 46-year-old female were infected with Sendai virus containing the Yamanaka factors to produce transgene-free human induced pluripotent stem cells (iPSCs). CRISPR/Cas9 was used to generate isogenic cell lines with a gene dose-dependent deficiency of CDH13, a risk gene associated with neurodevelopmental and psychiatric disorders. Thereby, a heterozygous CDH13 knockout (CDH13+/-) and a CDH13 null mutant (CDH13-/-) iPSC line was obtained. All three lines showed expression of pluripotency-associated markers, the ability to differentiate into cells of the three germ layers in vitro, and a normal female karyotype.

A Common CDH13 Variant Is Associated with Low Agreeableness and Neural Responses to Working Memory Tasks in ADHD.

The cell-cell signaling gene CDH13 is associated with a wide spectrum of neuropsychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD), autism, and major depression. CDH13 regulates axonal outgrowth and synapse formation, substantiating its relevance for neurodevelopmental processes. Several studies support the influence of CDH13 on personality traits, behavior, and executive functions. However, evidence for functional effects of common gene variation in the CDH13 gene in humans is sparse. Therefore, we tested for association of a functional intronic CDH13 SNP rs2199430 with ADHD in a sample of 998 adult patients and 884 healthy controls. The Big Five personality traits were assessed by the NEO-PI-R questionnaire. Assuming that altered neural correlates of working memory and cognitive response inhibition show genotype-dependent alterations, task performance and electroencephalographic event-related potentials were measured by n-back and continuous performance (Go/NoGo) tasks. The rs2199430 genotype was not associated with adult ADHD on the categorical diagnosis level. However, rs2199430 was significantly associated with agreeableness, with minor G allele homozygotes scoring lower than A allele carriers. Whereas task performance was not affected by genotype, a significant heterosis effect limited to the ADHD group was identified for the n-back task. Heterozygotes (AG) exhibited significantly higher N200 amplitudes during both the 1-back and 2-back condition in the central electrode position Cz. Consequently, the common genetic variation of CDH13 is associated with personality traits and impacts neural processing during working memory tasks. Thus, CDH13 might contribute to symptomatic core dysfunctions of social and cognitive impairment in ADHD.