Visit us at booth B06:11 and mark your itinerary to see these posters presentations:
Assessing Functional Effects of a KCNT1 Mutation Associated with Epilepsy Using Human iPSC-derived Neurons
(Wed, Jun 24 | 6:30 – 8:30 pm | Poster W-1330)
Authors: Hussey D, Mangan K, McLachlan M, Burke T, Meline B, McMahon C, Carlson C, DeLaura S, Jones E
The sodium-activated potassium channel Slack encoded by the gene KCNT1 is expressed in neurons throughout the brain, including the frontal cortex, and mediates a sodium-sensitive potassium current (IKNa). This outward current regulates neuronal excitability and determines how neurons respond to repeated high frequency stimulations, both of which are aspects of memory and learning. Mutations in KCNT1 and alterations to the IKNa current have patho-physiological consequences. Recent studies have described the emerging role of KCNT1 channels in cognitive deficits, and role of KCNT1 mutations in clinically distinct forms of severe early onset “childhood” epilepsies. The development of better therapies for neurological disorders has been hindered by limited access to clinically-meaningful cell for research and drug development. The advent of induced pluripotent stem (iPS) cell technology provides a platform to facilitate increased understanding of disease mechanisms in a physiologically-relevant human cell type. We have leveraged this technology to generate human neurons cells carrying the KCNT1P924L mutation and assessed the function effect of the mutation on physiology. To introduce the P924L allele, we genetically engineered a “control” iPS cell line from an apparently healthy female donor with no family history of neurological disorders and generated highly pure (>95% TUJ1-positive), and terminally differentiated cortical neurons from the KCNT1 P924L and isogenic control iPS cell lines. Here, we present data from the functional comparison of these human neurons (wild-type vs. KCNT1 P924L mutant), with a specific focus on the electrophysiological analysis using multi-electrode array (MEA). The ability to engineer isogenic wild type and disease associated alleles by genome editing human iPS cells gives researchers unprecedented access to models for neurological disorders. Our ability to produce pure populations of sub-type specific human neurons is revolutionizing our approach to studying diseases in vitro, and is opening new avenues to develop treatment for central nervous system diseases.
iPSC-derived Cardiomyocytes Produced from a Donor Carrying the MYH7-R403Q Exhibit Features of Hypertrophic Cardiomyopathy In Vitro
(Thur, Jun 25 | 6:00 – 8:00 pm | Poster T-1332)
Authors: Jones E, Hussey D, McLachlan M, Burke T, Carlson C, Anson B
Hypertrophic cardiomyopathy (HCM) is a common genetic heart condition affecting approximately 1 in 500 individuals, where the heart muscle becomes thick and blood flow is restricted. The condition is characterized by a thickening of the ventricular wall as a result of enlarged cardiac myocytes, changes in blood pressure due to restricted blood flow, and arrhythmias. The most prevalent form of familial HCM arises from a missense mutation in the gene encoding the beta-myosin heavy chain protein, resulting in a change of amino acid 403, from Arg-to-Gln (MYH7-R403Q). The study of diseases affecting cardiomyocytes has been advanced by the advent of stem cell technology which has enabled the production of stem cell-derived cardiomyocytes in sufficient quantities to facilitate large scale in vitro research. Further advances in stem cell technology enabled the production of human induced pluripotent stem (iPS) cells from any individual, apparently healthy normal as well as affected individuals, prompting production of large collections of iPS cells. Cardiomyocytes (CM) can be produced from any iPS cell in a collection and used to gain a better understanding of mechanisms involved in complex heart disease. Here we describe the study of iPS cell-derived CM from normal and MYH7-R403Q. Hypertrophy can be induced in normal human donor iPS cell-derived CM with exposure to Endothelin-1 (ET-1). HCM-induced CMs exhibit classic hallmarks of cardiac hypertrophy including up-regulation of fetal genes, cytoskeletal rearrangements, and an increase in cardiomyocyte size. We show that induced and inherited HCM in iPS cell-derived CM have common features. CMs differentiated from MYH7-R403Q iPS cells exhibit cardiac morphology, and showed autonomous contractile activity similar to the control iPS cell-derived CM. MYH7-R403Q CM and ET-1 induced HCM in normal CM have similar basal gene expression. ET-1 induction increases BNP expression in both control and MYH7-R403Q cardiomyocytes, but basal BNP levels are higher in MYH7-R403Q cardiomyocytes. These data show the progression of HCM characteristics in MYH7-R403Q cardiomyocytes and underscore the advantages of modeling cardiovascular disease with iPS cell technology.
The Utility of Induced Pluripotent Stem Cell (iPSC)-derived Cardiomyocytes and Hepatocytes as an In Vitro Human Model System for High Content Screening of Complex Chemical Substances
(Thur, Jun 25 | 6:00 – 8:00 pm | Poster T-1287)
Authors: Sirenko O, Grimm F, Iwata Y, Crittenden C, Rusyn I, Cromwell E, Lange S
In vitro model-based testing is part of routine safety evaluation of drugs and chemicals. Usually, screening is performed with pure compounds. In addition, chemical structure-based similarity “read across” is widely used for predictive safety assessments of non-pharmaceutical chemicals in regulatory submissions, especially in Europe. While either biological or chemical characterization of the potential human health hazard is sensible for chemically-characterized compounds, it is not applicable to assess the hazard of mixtures or complex substances (e.g., petroleum products). Thus, we suggest that safety evaluation centered on similarities in biological responses, i.e. a biological data-based read across, may represent a feasible alternative. In this work we tested a hypothesis that induced pluripotent stem cell (iPSC)-derived cardiomyocytes and hepatocytes represent a relevant in vitro model system that is applicable for high-content, multidimensional toxicity screening and biological read across of chemically complex substances. We selected 26 petroleum products from six distinct categories: SRGO (Straight Run Gas Oils), OGO (Other Gas Oils), VHGO (Vacuum & Hydrotreated Gas Oils), Bitumens, RAE (Residual Aromatic Extracts), and HFO (Heavy Fuel Oils). iPSC-derived cardiomyocytes and hepatocytes were exposed to a DMSO-based extract dilution series in logarithmical order over five logs for up to 48 hours. The cardiomyocyte-derived phenotypes included the measurement of effects on contractility, beating pattern and amplitude, as well as cell viability,morphology and mitochondria integrity measured through high-content live cell imaging. For hepatocytes we determined changes in cell viability, morphology, and mitochondria integrity by live and fixed cell imaging. Quantitative data were then used as high-dimensional “biological” data inputs for evaluation of the similarities and differences both within and across different substance categories. Our data clearly indicate cell- and substance group-specific effects. Collectively, our work demonstrates that iPSC- derived cardiomyocytes and hepatocytes are useful in vitro human model systems for high-content screening of complex chemical substances.