Human Pluripotent Stem Cell Based Developmental Toxicity Assays for Chemical Safety Screening and Systems Biology Data Generation

Efficient protocols to differentiate human pluripotent stem cells to various tissues in combination with -omics technologies opened up new horizons for in ...

Data Acquisition and Analysis In Brainstem Evoked Response Audiometry In Mice

Brainstem evoked response audiometry (BERA) is of central relevance in the clinical neurophysiology. As other evoked potential (EP) techniques, such as ...

University of Cologne

Pluripotent stem cells have great potential for regenerative medicine; however, their clinical use is associated with a risk of tumor formation. We utilized pluripotent cells expressing green fluorescent protein and puromycin resistance under control of the Oct4 promoter to study the persistence of potential pluripotent cells under embryoid body (EB) culture conditions, which are commonly used to obtain organotypic cells. We found that i.) OCT4-expressing cells dramatically decrease during the first week of differentiation, ii.) the number of OCT4-expressing cells recovers from day 7 on, iii.) the OCT4-expressing cells are similar to embryonic stem cells grown in the presence of leukemia inhibitory factor LIF but express several markers associated with germ cell formation, such as DAZL and STRA-8 and iv.) the persistence of potentially pluripotent cells is independent of supportive cells in EBs. Finally, OCT4-expressing cells, isolated from EBs after 2-month of culture, were further maintained under feeder-free conditions in absence of LIF and continued to express OCT4 in 95 % of the population for at least 36 days. These findings point to an alternative state of stable OCT4 expression. In the frame of the landscape model of differentiation two attractors of pluripotency might be defined based on their different characteristics.

Evidence for self-maintaining pluripotent murine stem cells in embryoid bodies.

Heart development is a complex process, tightly regulated by numerous molecular mechanisms. Key components of the regulatory network underlying heart development are transcription factors (TFs) and microRNAs (miRNAs), yet limited investigation of the role of miRNAs in heart development has taken place. Here, we report the first parallel genome-wide profiling of polyadenylated RNAs and miRNAs in a developing murine heart. These data enable us to identify dynamic activation or repression of numerous biological processes and signaling pathways. More than 200 miRNAs and 25 long non-coding RNAs were differentially expressed during embryonic heart development compared to the mature heart; most of these had not been previously associated with cardiogenesis. Integrative analysis of expression data and potential regulatory interactions suggested 28 miRNAs as novel regulators of embryonic heart development, representing a considerable expansion of the current repertoire of known cardiac miRNAs. To facilitate follow-up investigations, we constructed HeartMiR (http://heartmir.sysbiolab.eu), an open access database and interactive visualization tool for the study of gene regulation by miRNAs during heart development.

Parallel Genome-wide Profiling of Coding and Non-coding RNAs to Identify Novel Regulatory Elements in Embryonic and Maturated Heart.

Functional studies of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (hCMs) under different gravity conditions contribute to aerospace medical research. To study the effects of altered gravity on hCMs, we exposed them to acute hypergravity and microgravity phases in the presence and absence of the β-adrenoceptor isoprenalin (ISO), L-type Ca channel (LTCC) agonist Bay-K8644, or LTCC blocker nifedipine, and monitored their beating rate (BR). These logistically demanding experiments were executed during the 66th Parabolic Flight Campaign of the European Space Agency. The hCM cultures were exposed to 31 alternating hypergravity, microgravity, and hypergravity phases, each lasting 20-22 s. During the parabolic flight experiment, BR and cell viability were monitored using the xCELLigence real-time cell analyzer Cardio Instrument. Corresponding experiments were performed on the ground (1 ), using an identical set-up. Our results showed that BR continuously increased during the parabolic flight, reaching a 40% maximal increase after 15 parabolas, compared with the pre-parabolic (1 ) phase. However, in the presence of the LTCC blocker nifedipine, no change in BR was observed, even after 31 parabolas. We surmise that the parabola-mediated increase in BR was induced by the LTCC blocker. Moreover, the increase in BR induced by ISO and Bay-K8644 during the pre-parabola phase was further elevated by 20% after 25 parabolas. This additional effect reflects the positive impact of the parabolas in the absence of both agonists. Our study suggests that acute alterations of gravity significantly increase the BR of hCMs via the LTCC.

Parabolic, Flight-Induced, Acute Hypergravity and Microgravity Effects on the Beating Rate of Human Cardiomyocytes.

Induced pluripotent stem cell (iPSC)-based disease modelling and the cell replacement therapy approach have proven to be very powerful and instrumental in biomedical research and personalized regenerative medicine as evidenced in the past decade by unraveling novel pathological mechanisms of a multitude of monogenic diseases at the cellular level and the ongoing and emerging clinical trials with iPSC-derived cell products. iPSC-based disease modelling has sparked widespread enthusiasm and has presented an unprecedented opportunity in high throughput drug discovery platforms and safety pharmacology in association with three-dimensional multicellular organoids such as personalized organs-on-chips, gene/base editing, artificial intelligence and high throughput "omics" methodologies. This critical review summarizes the progress made in the past decade with the advent of iPSC discovery in biomedical applications and regenerative medicine with case examples and the current major challenges that need to be addressed to unleash the full potential of iPSCs in clinical settings and pharmacology for more effective and safer regenerative therapy.

Agapios Sachinidis

Center of Physiology and Pathophysiology,
Institute of Neurophysiology,
Faculty of Medicine,
Center of Physiology and Pathophysiology, Institute of Neurophysiology,
Institute of Neurophysiology, Faculty of Medicine

University of Cologne

Human Pluripotent Stem Cell Based Developmental Toxicity Assays for Chemical Safety Screening and Systems Biology Data Generation

Data Acquisition and Analysis In Brainstem Evoked Response Audiometry In Mice

Agapios Sachinidis

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Center of Physiology and Pathophysiology,Institute of Neurophysiology,Faculty of Medicine,Center of Physiology and Pathophysiology, Institute of Neurophysiology,Institute of Neurophysiology, Faculty of Medicine

University of Cologne

Human Pluripotent Stem Cell Based Developmental Toxicity Assays for Chemical Safety Screening and Systems Biology Data Generation

Data Acquisition and Analysis In Brainstem Evoked Response Audiometry In Mice

Center of Physiology and Pathophysiology,
Institute of Neurophysiology,
Faculty of Medicine,
Center of Physiology and Pathophysiology, Institute of Neurophysiology,
Institute of Neurophysiology, Faculty of Medicine